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Патент USA US3099883

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Aug. 6, 1963
w. E. BRAINARD ETAL.
3,099,873
SHUTTLE OPERATED TAPE coNTRoLLED MACHINE Toor.
Filed Nov. 28, 1958
6 Sheets-Sheet l
Aug. 6, 1963
3,099,873
» w.E.BRA1NARD ETAL
SHUTTLE OPERATED TAPE CONTROLLED MACHINE TOOL
Filed Nov. 28, 1958
6 Sheets-Sheet 2
INVENTORS
82W
Àug' 6, 1963
w. E. BRAINARD ETAL
3,099,873
SHUTTLE OPERATED TAPE coNTRoLLEn MACHINE TooL
Filed Nov. 28, 1958
6 Sheets-Sheet 5
4455
bmìßäNlnh
INVENTORS
Aug. 6, 1963
3,099,873
W‘ E. BRAINARD ETAL
SHUTTLE OPERATED TAPE CONTROLLED MACHINE TOOL
Filed NOV. 28, 1958
6 Sheets-Sheet 4
C
Z7
Dm@
Aug. 6, 1963
w. E. BRAINARD ETAL
3,099,873
SHUTTLE: OPERATED TAPE coNTRoLLED MACHINE Toor.
Filed Nov. 28, 195s
»
è sheets-sheet 5
IN VEN TORS
¿da flaca ê, 5rd f'ward
Kenneth ß. Werner
Aug. 6, 1963
w.E.BRA1NARD ETAL
3,099,873
SHUTTLE OPERATED TAPE coNTRoLLED MACHINE Toor.
Filed Nov. 2s, 195e
e sheets-sheet e
582965
\
INVENTORS
Í\
‘Y1
Q
.MEM
United States
atent ’
1
3,099,373
SHUTTLE OPERATED TAPE CONTROLLED
MACHINE TOOL
Waliaee E. Brainerd, Milwaukee, and Kenneth R. Merner,
Greendale, Wis., assignors to Kearney & Trecker Cor
poration, West Allis, Wis., a corporation of Wisconsin
Filed Nov. 2S, 195€, Ser. No. '777,122
24 Claims. (Cl. 29-26)
ice
3,'ü-99ß73
Patented Aug. 6, 1963
2
chine operations on a particular group of workpieces
comprising one lot. Another disadvantage is that after
setting up the machine to receive a particular workpiece,
and inserting the tape appropriate for that workpiece, it
is uneconomical to remove the tape and change Ithe
machine settings until a complete lot of workpieces had
been completed.
Tlhc usual prior art transfer machines, on the other
hand, comprise a plurality of different spaced apart work
This invention relates generally to automatic control 10 ing stations, with a transfer arrangement for sequentially
systems for machine tools, and more particularly to a
machine tool incorporating a Work carrying shuttle mech
anism and an associated numerical control system so
interconnected las to render the machine operable to per
advancing a workpiece from station to station, in .a man'
ner that a plurality of different required machining opera
tions can be performed. Such machines usually are set
up in advance to perform a plurality of different machin
form different programs of machining operations upon 15 ing operations upon extremely large lots of workpieces.
Furthermore, machines of this class are normally ex
correspondingly different w-orkpieces presented to the
tremely complex and expensive, incorporating in addition
working station in intermixed sequence.
to automatic transfer devices, automatic holding and posi
The prior art teaches both the »application of a program
tioning mechanisms to completely remove the necessity
or tape control system to ya single machine having one
working station, as well as the application of a conven 20 for manual adjustment or control during a sequence of
tional sequencing type control system adapted to effect
machining operations. Although transfer machines are
ing operations upon a particular workpiece. Obviously,
any of the working stations is reduced to an absolute
sometimes adapted to be adjusted for receiving workpieces
a plurality of machining operations on a workpiece in
of `different 4configuration at the completion of one pro
a transfer machine having a plurality of different work
duction run, this is not normally the case. in spite of
ing stations. In tape control as applied to a single ma
chine, it is possible to utilize either punched or magnetic 25 the fact that transfer machines are usually limited to ex
tremely large lots of workpieces, the principal advantage
tape to predeterminately program a plurality of machine
is, of course, the fact that nonproductive or idle time at
movements for performing a plurality of desired machin
minimum. To achieve .all of rthese advantages, however,
manual or Semi-automatic control of machine move 30 it has been customary to design transfer machines for
performing a plurali-ty of different machining operations
ments and placed a machining cycle comprising a plu
this type of machine control obviated the necessity for
rality of diiîerent positioning and machining operations
under control of a punched or magnetic tape. The utili
zation of tape control in the machine arts obviously rep
resented a considerable advancement in the art of ma
chining metal workpieces to predetermined configura
tions. One principal advantage was the complete elimi
on a particular workpiece.
In the event the transfer ma
chine incorporated adjustment for receiving different
workpieces, such workpieces usually had common char
35 acteristics and differed only in dimensions.
A principal object of the invention «is l‘to provide an irn
pi'oved machine tool -control system.
Another- object >of the invention is to provide an im
nation of any manual control or adjustments during a
preselected program of machine operations. Another ad 40 proved shut'tle type transfer mechanism.
Another object of the invention is to provide an im
vantage was the suit-ability of utilizing tape control for
proved shuttle transfer mechanism in combination with
relatively small lot production, thereby gaining a few of
an improved index table.
the advantages of automation in small lot machining op
Another object of the invention is to provide an im
erations. After one lot of workpieces have been com
proved system for activating a numerically controlled
pleted, another tape could be operatively associated with
machine tool and comprising .a plurality of separate pro
the control system for performing operations upon a dif
gram controllers selectively connectable to control ma
ferent lot of workpieces. Tape control, as applied to a
chine operation.
single machine, therefore reduced the principal manual
Another object of this invention is to provide a greatly
operations performed by an operator to inserting a new
tape in the machine control system at the start of machin 50 improved control system for a machine tool having a
single working station in combination with a cooperat
ing a different lot of workpieces, and making whatever
ing shuttle transfer mechanism so interconnected in the
additional machine operation adjustments that were re
machine tool system as -to effect alternate advancement
quired lat that time. One disadvantage of this arrange
of differently configured workpieces into the single oper
ment, however, is the fact that the operator necessarily
ating station, together with means for activating the con
had to manually remove one workpiece after a machining
trol sy'stem for performing 4an appropriate program of
program had been completed, and susbtitute the next
machining operations upon whichever of the workpieces
workpiece prior to star-ting the machine for the next pro
is in the operating station.
gram cycle. In the ycase of relatively small, and simple
Another object of this invention is to provide a machine
Workpieces, this presented no problem as the machine is
tool
and associated control system in Which a single tool
idle for a relatively slight time during manual removal 60
carrying spindle is operative to perform machining opera
of one workpiece and placement of the next workpiece
tions for a
of time during any operating period.
in the operating station. In the case of more complex
Another object of the invention is to provide a control
workpieces, however, considerable time is necessarily re
system for a machine tool `organization adapted to re
quired vfor 4the removal of a completed work-piece 'and re
ceive a 'wide variety of workpieces, means for performing
placement with Va new workpiece prior to the next ma 65 a plurality of preselected programs of machining opera
chine program. During the time required for setting up
tions upon different kinds of workpieces, and shuttle type
the next workpiece on the machine table, a single machine
transfer means for sequentially advancing different kinds
could he idled for a considerable period of time per
of workpieces -into the machine operating station, together
forming a repetitive program on complex Workpieces in
with means `for automatically connecting the machine to
the same lot. Therefore, a machine could be idle or 70 be operated through a particular program of machining
non-productive durin-g approximately 50% of the total
operations appropriate ¿for the workpiece that is then
time required for performing repetitive programs of ma
advanced into the operating station.
3
3,099,873
Another object of the invention is to provide an im
proved macthine -tool organization and control system
ers that are individually and selectively connectable to
effect a predetermined program of machine movements
incorporating means for successively performing different
for, in turn, effecting a predetermined program of machin
programs of machining operations upon correspondingly
ing operations upon a workpiece carried by the work sup
diiferent‘ .Workpieces alternately advanced into a single 5 port. A shuttle type transfer mechanism is provided to ad
machine working station, whereby ‘a single machine tool
vance one work carrying pallet from the working station to
may be utilized to perform a plurality of dìiferent pro
an unloading station, and simultaneously therewith, ad
grams of machining operations upon an intermixed se
quence of workpieces successively advanced into the Work
vance a different work carrying pallet from a different un
loading station into the machine operating station.A By
10 means of this arrangement, differently configured Work
ing station.V
Another object of the invention is toprovide an im
pieces, having different dimensions and machining re
proved shuttle mechanism having two spaced apart un
quirements, may be alternately moved into the operating
loading stations, together with means for transferring a
station upon the worktable. Simultaneously with the
completed workpiece from a machine operating station to
movement of a different pallet and its associated work
one unloading station, and simultaneously therewith trans 15 piece into the working station, secondary control means
ferring an uncompleted workpiece from yanother unload
are operative to connect a particular one of the tape read
ing station to the machine operating station.
ers for actuating the numerical control system in ac
Another object of the .invention is to provide a mach-ine
cordance with the machining requirements of the work
tool having a relatively movable tool support and co
piece then advanced into the operating station. Power
operating work support connectable 4to be controlled for 20 driven shuttle transfer means are selectively »actuatable
a predetermined program of relative work support and
tool support movements by a selected one of a plurality
to initiate ka shuttle movement, with the subsequent tape
reader switching being performed automatically to initiate
of alternatelyconnectable numerical tape control systems.
the required program of machining opera-tions upon the
Another object of the invention is to provide a machine
workpiece corresponding to the requirements of that par
tool in combination with a plurality of different preset 25 ticular program. In the interval that one workpiece is be
table program control systems respectively connectable
ing machined in the operating station, the other pallet,
to operate -the machine for performing a predetermined
sequence of machining operations upon Ia workpiece re
which has been moved into an unloading station, is re
loaded with an uncompleted workpiece in preparation for
the next, alternate program of machining movements.
A further object of the invention is to provide the great 30 By means of this arrangement, -it will be apparent that the
ly improved effects of transfer machine operation in a
tool spindle is operative to perform its primary function
single machine tool provided with a single |working station
of machining a workpiece for a maximum of time during
and a single cooperatively disposed tool carrying spindle.
each operating period. For example, this invention pro
A further object of the invention is to provide in a
vides 'a practical and operative means for effectively utiliz
machine tool having a bodily movable tool support and a 35 ing the tool spindle for performing machining operations
quiring that particular program of operations.
cooperatively disposed bodily movable work support; a
approximately ninety (90) percent of the time. In average
plurality of power driven translators connected to eiîect
single machine tools well known in the prior art, by com
bodily movement of the work support and tool support in
parison, effective tool utilization is usually considerably
combination with a plurality of different prese-ttab‘le con
f less than ñfty (50) percent of the total machine operating
trol systems alternately connectable to effect selected op 40 time. In other words, a much greater percentage of time
eration of the power driven translators for effecting dif
has been heretofore required for initially setting up a
ferent predetermined programs of movement of the tool
machine to accommodate a differently configured work
support and work support, in a manner that the machine
piece; for unloading one completed workpiece from the
is operable to receive differently configured Workpieces
requiring different programs of machining operations.
machine operating station; and for properly mounting
the next uncompleted workpiece in the work operating
A still further object of the‘invention is to provide
a machine tool organization that is automatically opera
tive to perform different selected programs of machining
station las a prerequisite for starting the spindle to per
form the next series of machining operations.
In a modified form of the invention, a tool storage
operations upon different workpieces alternately advanced
drum including Ia tool change mechanism is carried in
into the machine operating station.
50 operative relationship with the single, power driven tool
A still further object of the invention is to provide
spindle, and is operative to automatically withdraw one
a machine tool organization including a cooperatively dis
tool from the spindle, and reinsert a different preselected
posed work support and tool support in combina-tion with
tool in the spindle, laccording to the requirement of the
an associated control system that is automatically opera
machining program. Thus, diiferent Itools can lbe selected
tive to control machine movements for a plurality of dif
55 for insertion into the tool spindle in la manner that dif
ferent programs of predetermined cooperating move
ments, and including feedback control means operative to
modify the operation of the control system.
According to this invention, a machine tool having
a bodily movable tool support and a cooperatively dis 60
ferent kinds of machining operations may tbe effectively
incorporated in the program of machining operations on
either of the differently configured workpieces alternately
presented to the Working station.
Before starting a relatively continuous shuttle type
posed selectively indexable work support is provided with
program of machining operations, the tool storage drum
power driven translators responsive to a numerical con
is provided with a plurality of different cutting -tools -ap
trol system. The numerical control system is operative
propriate for one workpiece, and a plurality of other cut
to4 selectively activate the various power driven transla
ting tools appropriate for lthe alternately presented work
tors for effecting a selected predetermined program of 65 piece. Thus, with the »tool storage drum and -tool changer
positioning and velocity controlled bodily movements of
opera-tively associated with lthe tool spindle, each of the
the cooperating work support and to-ol support. Position
diüerently conñgured workpieces ‘alternately 4advanced
indicating means associated with each of the axes of
into the machine operating station may be completely
movement of the bodily movable tool support and work
machined Without manually interchanging tools, or chang
support, as well as veloci-ty indicating means associated 70 ing the machine set up. 'Iîhe tool storage drum, for eX
with these members and a power driven rotatable tool
ample, is adapted to support a plurality of different cut
spindle are connected to modify the operation of the
ting tools, such as drills, taps, and face mills of Varying
numerical control system in accordance with the input re
sizes that may be required for performing a particular
quirements. For activating the numerical control sys
series of machining operations upon either of the dif
tem, there are provided a plurality of different tape read 75 ferently configured workpieces. In eñìect, with the tool
‘3,099,873
5
storage drum and tool changer operatively interconnect
ing in the numerical control system for the machine, the
single spindle machine tool embodying the novel features
of this invention is adapted 4to perform a plurality of dif
6
lied form of the invention, illustrating -a selectively index
able tool storagedrum and tool change mechanism op
eratively Iassociated with a xsingle power driven »tool spin
d-le;
FIG. 13 is an enlarged fragmentary exploded perspec
Iferent machining operations that would be comparable u.
tive view of the tool change mechanism and associated
to machining operations normally performed in a multi
tool supporting spindle, «and illustrating al-l of the various
spindle transfer machine. Thus, the single machine tool,
with the novel features illustrated by the preferred em
movements necessary to effect a required tool change
cycle;
bodiments fully disclosed in this application, is opera
FIG. 14 is a schematic view of a hydraulic control cir
tively adapted to provide the economies normally as 10
cuit operative to effect a tool change cycle; and,
sociated with transfer machine «operation into relatively
small lot production that has heretofore been most effec
-tively accomplished by a plurality of different, single
purpose machine tools.
The foregoing and other objects of the invention, which
FIG. 15 isa diagrammatic view of an electrical control
circuit yfor actuating the tool change mechanism.
Referring to the drawings, and particularly to FIGS. 1,
4 and l9, there is shown a machine tool of the bed type
incorporating a preferred embodiment of the invention,
and that is operable to perform a plurality of machining
operations such ‘as drilling, tapping, boring and face mill
exemplifying embodiments, depicted in and described in
ing.
The machine tool illustrated in FIG. l comprises
connection with the accompanying drawings in which:
FIGURE l is a view in perspective of a machine tool 20 essentially la rearwardly extending supporting frame or
bed 18, having formed on its upper rearward portion a
embodying the principles of this invention, and showing
pair
of Aspaced -apart way surfaces 19 and 20 disposed to
a pair of work supporting pallets in combination with -a
slidably ’support ian upwardly extending vertical column
novel shuttle type transfer mechanism;
21 for longitudinal movement. The column 21 is in
FIG. 2 is an enlarged fragmentary view in transverse
vertical section through a portion of the table supporting 25 tegrally formed with a laterally extending base section 22,
Iand is provided on its underside with way surfaces com
base, index table, and one of the work carrying pallets,
plementary to Ithe way surfaces 19 and 20. A vertically
and being taken generally along the ‘line 2-2 in FIG. 5;
movable saddle 26 is provided with vertically extending
FIG. 3 is an enlarged fragmentary view in perspective
way surfaces (not shown) ioperative to engage way sur
showing the index table drive #gear and the cooperating
will become more fully apparent from the following de
tailed speciñcation, may be achieved by means of the
clutch element for retaining the worktable in a selective 30 faces 27 and 28 presented by the column 21. I-n a similar
manner, -a spindle supporting head 29 provided with way
index position;
surfaces 30 is guided -by `complementary way surfaces pre
FIG. 4 is an enlarged fragmentary view, partly in front
sented by .the saddle 26 for transverse adjustment of a
elevation, and partly in longitudinal vertical section of
power driven tool spindle 34 that is journalled for rota
the table and the rightward portion of the shuttle mech
anism, with certain parts broken away to illustrate the 35 tion «ab‘out'a horizontal axis. The usual gibs (not shown)
are operatively disposed to retain the spindle head 29‘,
shuttle drive for one shuttle ßbar;
the saddle 26, and the `column 21 in slidable engagement
FIG. 5 is -an enlarged Áfragmentary plan view of the
with their .respectively -associated supporting members in
rightward portion of the shuttle mechanism, showing one
well known manner. By means of this arrangement, it
of the pallets moved into an operating station upon the
rotary table, and the other of the pallets being retained 40 will be readily apparent that the power driven tool spin
dle 34 is carried for bodily movement in three mutually
in the unloading station;
perpendicular planes, indicated in the drawing -as the X
FIG. 6 is an enlarged Ifragmentary plan view of the
axis, Y axis, and Z
rotary table constituting the operating station, together
As shown in FIG. 1 and as schematically represented
with that portion of the shuttle mechanism spaced left
45 in the block diagram, FIG. 11, power for driving the tool
wardly `from the rotary table;
spindle 34 -is derived from a reversible motor 3S. From
FIG. 7 is an enlarged fragmentary view in transverse
the motor 35, power is transmitted via lgears 36, 37, and
vertical section, taken generally along the lines 7-7 in
thence through a variable speed transmission 38 to rotate
FIG. 4, and showing the roller means for guiding the
shuttle bar during longitudinal movement together with
a gear 41 connected directly to drive a gear 42 secured
of one of the pallet engaging fingers, together with its
supporting bodily movable lshuttle bar, and showing the
cooperating cam actuated iinger re-tracting mechanism;
mechanisms respectively `operable to effect movement of
the column 21, saddle 26, and spindle head 29. As
shown in FIGS. 1 and 1l, the output shaft of the motor
50 to the rotatable tool spindle 34. Power for effecting
the associated drive means for effecting movement;
bodily movement of the tool spindle 34 along the X,
FIG. 8 is an enlarged fragmentary, detailed view illus
Y or Z axes, is supplied by reversible drive motors 45, 46
trating the operating position of one of the pallet engag
and 47 respectively. Each of the motors 45, 46 and 47
ing fingers Itogether with an associ-ated shuttle bar and be
is of the reversible variable speed type, and each of
ing taken generally 4along the line 8_8 in FIG. 5;
FIG. 8A is an enlarged fragmentary view in perspective 55 them is connected to act-nate screw and nut translating
45 is connected to rotate a feed screw 49 having op
FIG. 9 is ian enlarged diagrammatic view illustrating
the indexing and clamping mechanism for «the rotary ta 60 erative engagement with a feed nut 50 lixedly secured
to the underside of the column 21. The shaft of the
ble, as well las 'the clamping mechanism for the pallet
motor 46 is connected to rotate a screw 52 that engages
clamp, in combination with the associated actuating hy
draulic circuit;
FIG. 10 is ìa line diagram `of a control circuit for effect
ing a shuttle »transfer movement, together with the asso
a feed nut 53 carried by the saddle 26. In =a similar man
ner, the motor 47 is operative to rotate a feed screw 55
65 that is engaged by a feed nut 56 secured to the inner
portion of the spindle head 29. By means of this arrange
ment, selective energination of the motors 45, 46 or 47
operates to effect a lcorresponding bodily rectilinear move
a required one of the tape readers to actuate the numerical
ment of the power driven tool spindle 34 along either
control system;
FIG. 11 is a diagrammatic block diagram of a pre 70 the X, Y, or Z axes. Likewise, coordinate energization
of ftwo or more of the driving motors 45, 46 and 47 will
ferred form of numerical control system for effecting
operate fto effect bodily movement of the tool spindle 34
machine movements in combination with diagrammatic
along a resultant path of travel determined by the velocity
representations of the power driven translators for effect
of each of the slides along its separate axis. Normally,
ing the various member movements;
FIG. 12 is a fragmentary perspective view of a modi 75 simultaneous energization of two or more of the motors
ciated actuating means for clamping and unclamping a
pallet to the table, las well »as operatively interconnecting
7
3,099,873
8
is eiîected only for the purpose of moving the toolY
a new workpiece is secured to that’pallet. Therefore, the
power driven tool spindle 34 is operative to perform cut
ting or machining operations continuously, excepting for
spindle 34 to a predetermined position as a prerequisite
to operating aselected one of these motors for effecting a
required work engaging machining operation.
a slight time interval required to effect a shuttle or trans
As will hereinafter Ibe more fully explained, the tape
fer movement of the pallets, .i.e., movement of one pallet
into the working station upon the table 53 and corre
control system schematically shown in F‘IG. 11, is pro
vided with two separate tape readers 51 and 52 and that.
are alternately and operatively connectedv to activate the
sponding movement of the other pallet from the working
station to one or another of the unloading stations 57
or 58. Likewise, in either case, the control tapes (not
motors automatically for moving the `tool spindle through
-two diiferent predetermined programs of successive ma
chining cycles. Each of the machining cycles comprise
10 shown) respectively advanced relative to the tape readers
51 or 52 must provide a program of machining operations
two principal sequential components of movement, i.e. a
required by workpieces advanced into the working station
positioning component and an actual workpiece engaging
cutting component during which a `cutting tool is moved
by the Vpallets 54 :or 55' respectively.
Irrespective of whether the machine is utilized to per
from a particular preselected position to perform a se~ 15 form successive different programs of machining opera
lected machining operation. In some cases, of course, two
tions upon an intermixed sequence ofy workpieces, or
machining operations may be effected from the same
successive programs of identical machining operations
preselected position. Even in such cases, however, a
upon a sequence of like workpieces, the tool spindle 34
machining cycle includes a signal for coniirminlg the previ
is operative to perform its primary function of machining
ous preselected position immediately prior to the next 20 workpieces for a maximum of time during each operating
machining component of movement.
period. In other words the tool spindle is continuously
VFor supporting a workpiece during a machining opera
operable to machine an intermixed sequence of work
ltion, there is provided a rotary table 53 journalled for
pieces for approximately ninety (90) percent of the time.
rotation »about a vertical axis within the central forward
This invention completely »obviates lost productive time
portion of the frame 18, as shown in FIGS. l and 9. 25 of the tool spindle that is normally necessary in changing
As will hereinafter be more fully explained, the rotary
the machine set up or manually changing tapes whenever
table 53 is selectively rotatable from a home position,
diíerent workpieces are to be machined upon the same
represented in FIG. l, to V'one of a plurality of index sta
machine. It likewise provides a relatively continuous
tions in a manner that machining operations may be per~
output of two ydifferent kinds of workpieces from a single
formed upon a plurality of different faces of a workpiece
(not shown) carried thereby. In 'order Ito actually sup
30 machine. Thus, in industries requiring relatively small
lots of production, the necessity of stockpiling or carrying
in inventory completely machined lots of workpieces is
reduced considerably. Heretofore, it has been customary
port and secure a workpiece to the indexable table 53,
there are provided two work carrying pallets 54 »and 55.
As shown in FIG. l, the work pallet 54 is represented as
being moved into an operating station above «the work
table 53, and the pallet 55 has been moved to a load
ing and unloading station 57 that is spaced rightwardly
from the worktable. During machine operation, and
35
to set up a machine for one kind of workpiece and ma
chine a complete “lot” of 10 to 50 workpieces of that
particular type. Next, the machine set up was changed
to accommodate a different lot of workpieces and «another
“lot” of l0 to 50 workpieces of that type of workpieces
While a selected program of predetermined machining
machined and placed in inventory. Subsequently, work
operations is being performed upon one workpiece car 40 pieces were withdrawn from inventory for use in assem
ried by the pallet 54, a different completely machined
bly operations. Obviously, in such well known prior
workpiece isremoved from the pallet 55, and another
manufacturing
processes, relatively large quantities of
uncompleted workpiece of that configuration is secured
completed workpieces were necessarily carried in inven
to the pallet 55 by the machine operator. Thus, unload 45 tory, with the inventory being replenished by similar size
ing and loading of the pallet 55 is effected in the loading
“lots” of the same type workpiece being machined with a
station 57.
single machine set up.
After a program of machining operations has been
Utilization of the present invention greatly reduces the
performed on a workpiece carried by the pallet 54, both
necessity for maintaining an inventory of completely
of the pallets 54 and 55 are caused to be moved left 50 machined parts. By providing an output of diñîerent com
Wardly, the pallet 54 being moved into a leftwardly
pletely machined workpieces from the same machine, the
spaced unloading station 58 and the pallet 5S carrying
process of machining and subsequent assembly can be
a new workpiece being moved into operating position
maintained on a relatively continuous basis, with inter
upon the rotary table 53. A principal advantage of the
vening inventory being eliminated or reduced to an ab
present invention is the fact that workpieces requiring 55 solute minimum. Although the embodiment of the inven
different programs of machining operations may be placed
upon the pallets 54 and 55 respectively. The various
movable machine members are automatically operative to
tion in this disclosure illustrates two pallets -and an asso
ciated machine controlled for sequentially producing two
workpieces, the inventive concept of intermixing work
perform two completely `different programs of machining
pieces from Ia single machine is deemed to include any
operations, in accordance with the particular workpiece 60 practical
larger number of pallets and workpieces.
and pallet that is moved into an operating position upon
To guide 4and support the work pallet 55 for movement
the rotary ltable 53. rIhus, the machine is operable to
from the Worktable 53 to the unloading station 57, the
perform two different programs of machining operations
frame 13 is provided with spaced apart Way surfaces 6i)
upon an intermixed sequence of workpieces alternately
Iand `61. In a similar man-ner, the pallet 54 is guided for
advanced by sequential movement of the pallets 54 and 65 leftward
movement to the unloading station S8 upon way
55 into the operating station upon the rotary table 53
surfaces 62 and 63 integrally formed with the supporting
at the completion of each machining program upon the
frame 18. Both of the pallets 54 and 55 are provided
preceding workpiece.
with complementary way -surfaces respectively disposed
In addiion, it will be apparent that workpieces of like
to engage the left frame Way surfaces 62, 63 and the right
configuration and requiring identical programs of ma 70
frame way surfaces 6G» and 61. As a prerequisite to ef
chining operations may be sequentially moved into the
fecting shuttle or transfer movement of a pallet in`either
working station by the pallets 54 and 55. In either case,
direction, it is necessary that a clamp element 65 carried
one of the pallets 54 or 55 is moved into the working
by the «rotary table 53 for vertical movement is in upper,
station upon the table 53, while the other of the pallets is
unclamped position in a manner that spaced apart Way
in one of the unloading stations, 57 or 58, Aat which time 75 surfaces 67, 68, integrally formed lwith the clamp element
3,099,873
9
are aligned with the cooperating frame way Surfaces 62,
63 and 60, 61.
The condition illustrated in FIG. l occurs immediately
prior to a leftward shuttle movement of the pallet 54
to the unloading station 5S and a corresponding left
Ward movement of the pallet 55 into an operating sta
tion upon the clamp element ways 67, 68 above the
rotary table 53. As there shown, the worktable 53 has
been indexably returned to its home position in which
the ways `67 and 68 are longitudinally aligned with the
frame ways, and the -clamp element 66 elevated up
more clearly in the transverse sectional view, FIG. 7, in
which the laterally extending cam engaging pin 98 is
shown as being carried by a vertical support plate 106
secured at its lower end to the frame 1-8. As further
indicated in FIG. 7, the >guide rollers 89 and `90 are re
spectively provided with inwardly tapered, frusto-.coni
cally shaped opposite ends in a manner to engage the
‘opposite circular sides of the semicircular shuttle trans
»fer bar y88. To prevent rotational movement of the
shuttle «bar 88, the opposite side faces of a lgear rack
10S yfixedly secured to the underside thereof, are engaged
into horizontal alignment with the cooperating frame
by the opposed, horizontally formed faces of vguide shoes
109 and 110 respectively. The guide shoes 109 and y11€)
treme leftward parked position. Each pair of the spaced
/1-8. In addition to ycarrying the guide shoes, the support
wardly to move the upper surfaces of the ways 67, `68
are secured to the inner ends of transverse support plates
ways. Likewise, a longitudinally movable transfer bar 72
Supported for reciprocalble movement in `outer rollers 73 15 112 and; 113, the outer ends of which are ñxedly se
:cured to the vertically extending side walls of the frame
and spaced apart inner rollers 74 is retained in an ex
plates 112 and 113 likewise lconstitute a supporting base
for the guide roller shafts `89 and 90 respectively, and
77, 78 `fixedly secured to the supporting frame 18. When 20 the vertical support plate 106. Inasmu-ch as all of the
guide rollers 89 and l90, spaced along the frame 18 in
ever the left transfer bar 72 is in its extreme leftward
opposed pairs as shown in FIG. 5, are supported in
position, as shown in FIGS. l and 6, a pair of pivotably
generally similar fashion, the description pertaining to
mounted transfer fingers v82 and 83 are urged into down
FIG. 7 is deemed sufficient to `describe this entire ar
ward, fully retracted position -ïby means of inwardly ex
tending cam actuating pins 84 and `S5 that are fixedly 25 rangement with one exception. As shown ‘in FIG. 5,
the lcam engaging pin 99 is secured to the upper end off
secured to the frame 18. Thus, with the transfer bar
a ver-tical support plate 107 extending upwardly from the
72 in extreme leftward position, the transfer fingers `S2
transverse plate 112 and operates to engage a laterally
and 83 are fully retracted to permit a leftward move
extending cam plate -11'7 secured to the outer «face of
ment of the work supporting pallet 54 from the operat
ing station to the unloading station 5S upon the left frame 30 the rear pallet engaging, shuttle finger 97. Thus, dur
ing a leftward shuttle movement of the 1bar y88, `the lat
ways 62 and l63.
erally extending pin ‘98 associated with the forward trans
The transfer `bar 72 is in the same horizontal plane,
fer finger 96 will not interfere with the oppositely ex
although spaced apart laterally »from a transfer bar 8d,
tending cam plate 117.
which is guided for reciprocable transfer movement from
For effecting reciprocable transfer movement of the
a rightward parked Iposition, shown in FIGS. 4 and 35
shuttle tbar `8S, as shown in FIGS. 4 and 7, the -gear rack
5, by means of a plurality of outer rollers `S9 and eo
1% «fixedly secured to the underside of the bar ‘8S is
operating inner rollers 9G. Each of the opposed spaced
engaged by a gear 1118 carried by a horizontal shaft
apart transfer rollers 89, 99 is journalled to rotate about
apart rollers 73, 74 are respectively journalled to rotate
about corresponding pairs of upwardly extending shafts
corresponding pairs lof vertically disposed shafts 93 and 40 119 journalled at its opposite ends within bearings (not
shown) carried by the opposite walls of Iframe 18. Power
94 secured to the rightward portion `of the supporting
frame 18.
Prior to initiating a leftward shuttle move
[for rotating the »gear 118 t-o effect the required reciproca
Jble shuttle movement of the bar y88 is derived from a
ment, the transfer bar 8S is in an extreme rightwar-d
reversible hydraulic motor 120 secured to the outer front
position in a manner that transfer fingers 96 and v97 piv
otably secured thereto are in downwardly retracted po 45 wall of the frame 1S and connected to rotate the shaft 119'.
in a similar manner, as shown in FIGS. l, 6 and 9,
sui-on.
power for effecting reciprocable movement of the shuttle
Whenever the transfer bar S8 is moved to an extreme
lbar 72 is derived from another hydraulic motor 122 se
Iightward position, the transfer fingers 96 and 97 are
cured to the outer front wall of the frame 18. The mo
retained in downwardly retracted position =by means of
inwardly extending, horizontally disposed cam actuating 50 tor 122 ‘operates to rotate ~a pinion 123 having meshing
engagement with a longitudinally extending gear rack
pins 9g and 99 fixedly secured to the rightward portion
121i-, FIG. 9, scoured to the underside of the shuttle bar
of the frame 18. inasmuch as each lof the transfer iin
72. The arrangement for restraining the shuttle bar 72
gers 96, 97 associated with the transfer bar ‘83, as well
`against rotation; 'rotatably supporting the guide rollers 7 3,
as the retractable transfer Ifingers 82, `S3 associated with
the transfer bar 72 operate in identical fashion7 it is 55 74; and, effecting movement of the transverse fingers 82,
83 to downward retracted position is generally similar
deemed necessary to ‘describe in detail Áthe operation of
to that hereinbefore described with reference to FlGS.
only one of these fingers, as shown in FIGS. 8 and 8A.
4, 7 and S. It should -be noted, however, that the opp-o
As there indicated, the transfer ñnger 96 is disposed
sitely disposed, inwardly extending cam engaging pins 84
within a vertical slot or pocket 1112 formed toward the
leftward end of the transfer bar y83. A horizontal pin 60 Iand vS5, FIG. A6, operate to engage opposite‘ly extending
103 extending through the slotted end Iof the bar '88 piv
ota‘bly supports the retractable transfer finger 96 in a
manner that a compression spring 164 «disposed within
cam flanges 127, 128 respectively secured to the opposite
side faces of the pivotable transfer fingers `S2 and 83.
This is necessary, as hereinbe-fore explained with refer
ence to the guide bar 88, in yorder that the laterally ex
tending
pin 85 will not interfere with the cam plate y127
normally urge the -finger 96 upwardly. Upward move 65
secured to `the leftward transfer finger 82 during a full
ment of the ñnger 96 is limited by engagement of the
rightward transfer movement of the bar 72.
rightward underside thereof with the lower wall of the
inasmuch as the operating cycles for the shuttle bars
slot. As the transfer bar SS is moved to its extreme,
a 4circular vertical recess formed in the finger operates to
rightward parked position, a laterally extending cam plate
72 and `Sti» Iare identical, it is deemed necessary to de
105 secured to the side face of the finger 96 is engaged 70 scribe only one complete `operating cycle for the shuttle
bar S8 for illustnative purposes. I-t will be apparent that
by the inwardly extending :cani actuating pin 98. The
the bars 72 and 3S are alternatively operable in accord
pin 98 engages the cam plate 10S to urge the transfer
ance with the position sof the work carrying pallets 54
finger 96 downwardly into retracted position within the
and 5S respectively. In other words, whenever the pal
pocket 102 in opposition to the spring 104.
The «fully retracted position of the finger 96 is shown 75 lets 54, 55 are positioned as shown in lFIG. 5, the trans
3,099,873
11
fer ihar '8S is caused to move leftwardly to in turn move
both of the pallets to the positions indicated in FIG. 6.
At the completion lof a pro-gram of machining operations
upon a workpiece carried by the pallet 55, FIG. 6, the
shuttle bar 72 is rthen caused to move rightwardly for
moving the pallet '55 to the unloading station 57 and re
turning the pallet 54, with a different workpiece secured
thereto, into an operating position above the indexab-le
work supporting table.
To initiate a 'leftward shuttle movement, the motor 120
is energized «to effect >counterclockwise rotation of the
gear 118 for in turn effecting leitwa'rd longitudinal move
ment of the rack 168 and shuttle .bar 88, as shown in
FIGS. 4 land 7. As the cam plates 165 and 11'7 are moved
out of engagement with the iixedly positioned lateral pins
98 and 99, during leñtward movement, the pivot-able lin
gers 96 and 97 are resiliently biased upwardly to their
pallet engaging positions, FIG. 1. During continued leit
ward movement of the bar >83, the lingers 96, 97 engage
the rightward side faces of the pallets 54, 55 respectively
to effect a leftward transfer movement.
Whenever the worktable is in its home position and the
clamp member 66 elevated to a disengaged position as
12
a hydraulic control circuit, as schematically represented
in FIG. 9. The hydraulic control system is operable to
efl’ect the required vertical movement of the ‘clamp ele
ment 66, as well :as effecting the required vertical move
«ment of the ysupporting rotatable table 53 relative to the
supporting frame. Vertical movement lof the table 53 is
necessary to disengage the table from one angularly
clamped, indexed position las a prerequisite to effecting
the required rotational movement of the «table to its next
selected index position. The structure and mode of op
eration of both the vertically movable clamp element 66
and cooperatively movable work supporting table 53 is
more >fully shown and disclosed in United States Patent,
Serial No. 3,054,333, issued to Wallace E. Brainard.
Whenever the clamp element 66 is urged downwardly
to clamp a pallet, such as the pallet 54' in FIG. 9, to the
table 5'3, the table may be elevated to unclamped posi
tion, permitting energization of a drive motor 15-1 for
rotating the table to its next selected index position at
which time it is reclamped to the bed. As shownin
FIGS. 2, 9 and 1'1, the motor 151 is connected to rotate
a vertically journalled shaft 152 carrying a pinion 153
having meshing engagement with a ring gear 154 inte
grally formed with the inner hub of the Worktable 53.
direction, :a plurality of guide »rollers carried by the 25 Upon arrival of the table 53 at its next selected index
clamp member `66 for rotation about vertical axes are
position, the motor 151 is de-energized and the entire
properly aligned with .the various guide rollers carried by
table together with the pallet clamped thereto is moved
the frame 1-8. As shown in FlGS. 2 and 5, guide rollers
downwardly into clamped engagement with the support
130 to 133 inclusive are rotatably supported by four
ing frame 18. For retaining the table 53 in clamped
separate vertical shafts 134, 135, 136 and 137 spaced 30 engagement with the supporting frame 18, there is pro
equidistant from the axis of rotation of the table and
vided a disengageable coupling 156. To this end, the
being secured at their lower ends tothe clamp element 66.
central hub 150 of the table is provided on its lower face
Thus, during continued leftward movement of the guide
with circumferentially spaced, radially formed angular
har 88, the forward end thereof is supported iby 'being en
clutch teeth 157 disposed to have meshing engagement
required for the start «of a transfer movement in either
gaged between the outer roller 138' and the center rollers 35 with complementary clutch teeth 158 integrally formed
13‘1, :133. Upon further leftward movement, the left
Iwardly moving transfer bar 88 is engaged between one
of the rollers 74 and a cooperatively disposed roller 141,
toward the central portion of the frame 1-8. Movement
of the table 53 together with its supporting hub 150 down
wardly operates to urge the clutch teeth 157 into tight
as shown in FIG. 6. Leftward movement of the guide
meshing engagement with the ñxed clutch teeth 158, thus
-bar 88 continues until the pallet 55 is properly positioned 40 retaining
the table in a selected position of angular adjust
rover the rotary ta'ble 53 and the pallet 54 is moved into
ment, as well as positioning it in a plane perpendicular
the #left unloading station 58. As this occurs, the extreme
leftward end of the rack i108 secured to the underside of
fthe bar 88 enga-ges the actuating plunger of a limit switch
142 that is operatively connected to effect reversed rota
tion of the motor 120, as sho-wn in FIGS. 6 and 9.
Thereby, 'the motor 120 operates to rotate the pinion 118
to the axis of table rotation.
To support the table 53 for both rotatable and vertical
axial movement, the inner portion of the hub 150 is rotat
ably journalled about a sleeve bearing 1160 integrally
formed toward the upper end of an axially movable
tubular support element 161.
_
in a clockwise direction :for immediately returning the
'I‘he tubular support element 161 is restrained against
guide bar A88 rto its extreme rightward, parked position in
which the pallet engaging finge-rs 96, 97 are retained in 50 rotation and guided for vertical slidable movement
a vertically bored opening 162 constituting a circular
downwardly retracted position, as liereinbefore ex
b_earmg surface and being formed within the central por
plained. Upon -arrival of the guide bar in rightward
tion of the frame 18. At its lower end, the tubular ele
parked position, the rightward end of the rack 108 se
ment 161 is secured to a transverse plate 163 having
cured to the Ibar engages an actuating plunger associated
with another limit switch 145, which is connected upon 55 secured'to its opposite upper faces a pair of vertically
upstandmg cylinders 164 and 165. Stationary, vertically
actuation to effect de-energizati-on of the motor 12B.
disposed piston rods 169
In a similar manner, upon a rightward shuttle move
ment of the Work carrying pallets, a yreverse limit switch
147, FIG. 5, is positioned to be actuated Iby .the rack (not
_
and 170 secured -at their upper
ends directly to the stationary frame 18 are provided-at
the1r lower ends with stationary pistons 171 and 172 re
shown) secured to Íthe underside of the transfer .bar 72. 60 spectively carried for slidable movement within the co
operating spaced apart cylinders 164 and 165. By means
Actuati‘on of the switch 147, upon return arrival of the
pallets 54, 55 to the positions show-n in FIG. 5, operates
to effect reversed rotation of «the motor 1122 for returning
the guide bar 72 to its extreme left-ward parked position,
shown in FIG. 6. As this Ioccurs, and 'with the pallet en
gaging lingers :82, `83 pivotably moved to downward re
tracted position, a limit switch 148 is actuated to stop
rotation of the motor `1-22. for retaining the guide bar 72
of this arrangement, it will be apparent that the tubular
support 161, transverse plate 163, together with the cylin
ders 164 and 165 are vertically movable relative to the
statlonary pistons 171 and 172 respectively carried for
slldable movement within the cooperating spaced apart
cylinders 164 and 165. It will be apparent, likewise, that
the tubular element 161 and transverse plate 163 are con
strained against rotational movement. Switches 173 and
movement :of the other guide bar 88, FIG. 5.
70 174 are actuated upon vertical movement of the tubular
In order -to effect fthe required ‘alternate actuation of
member 161 and support plate 163. Whenever the table
the shuttle transfer bars 72 and 88 in properly coordinated
53 is elevated to its disengaged position, ‘as shown in FIG.
relationship with movement of the clamp element 66 to
9, the -leftward end of the support plate actuates switch
upper disengaged position at the completion of a pro
173. In a similar manner, upon movement of the table
in parked position during a later, subsequent shuttle cycle
gram ‘of machining operations, FIG. l, there is provided 75 53 and tubular support member `161 to downward clamped
’3,099,873
13
position with the radial clutch teeth 1'57 engaging the
complementary clutch teeth '158, the suppont plate 163
actuates switch 174.
-For effecting vertical movement of the table 53, the
cylinders 164 and 165 are connected to be hydraulically
actuated relative to the stationary pistons 171 and 172.
To accomplish this, the hydraulic circuit is activated by
energizing a motor »177 by means of a control circuit
shown) in well known manner. The motor 177 is
nected to drive a pump 178 connected to withdraw
from a sump i179 and transmit fluid under pressure
central portion of the tubular support member 161. Thus,
movement lof the piston 219 within the cylinder 220 ef
fects a corresponding movement of the pivotably intencon
nected rods 217 »and 214 to etïect the required vertical
movement of the clamp element 66. Inasmuch as the
Worktable locating pins are utilized to initially position the
(not
pallet, the piston 219 is ñrst urged downwardly under a
con
ñuid 10 low clamping pressure with a subsequent high clamping
pressure being applied for retaining the pallet 54 in tight
to a
main pressure supply line 180. From the pressure supply
line 180, the flow of iìuid continues via a predeterminately
adjusted throttle control valve to abranch-line 183 connect
ed to an inlet port formed in a control valve 185.
14
cured to a piston 219 constrained ñor slidable movement
a cooperating cylinder 220 formed within the lower
engagement with the table 53 during machining «opera
tions. To accomplished this, pressure fluid from the main
Ihigh pressure supply line 18€) is connected via »a throttle
With a 15 control valve 221 to a pressure differential valve 222 which
ends of the cylinders 164 and 165 respectively. Admis
is operative in a well known manner to supply hydraulic
iluid at the required reduced pressure to a branch line
223. inasmuch as the pressure differential valve 222 oper
iates to reduce the pressure »and volume of fluid to the line
223, the valve is connected to return a predetermined
quantity off diuid to the sump 179 via a by-pass line 224.
downward clamping movement is eíîected by energizing
reduced clamping pressure is being applied to the piston
198 in the rightwardly displaced valve spool 187 to the
233 in resiliently biased leftward position.
spring 186 urging an axially slidable valve spool 187 left
wardly, as shown in FIG. 9, pressure fluid is transmitted
from the control valve 185 :through a drilled line Aformed
in the valve spool 187 to a hydraulic |line 190 connected
at its opposite ends to supply pressure iluid to the upper
'Ilo effect downward clamping movement of the pallet 54,
sion of pressure fluid to Ithe upper ends of the cylinders
a valve spool 226 of `a clamp ‘control value 227 is normally
164, 165 from the line 190, in turn, operates to effect
urged to its extreme rightward position by means of Ia
upward movement of the worktable 53 to its disengaged
or unclamped position. At the same time, fluid -is ex 25 solenoid 228.
With the valve spool 226 moved rightwardly, as shown
hausted from the lower ends of the cylinders 164 and
in FIG. 9, the iiow loif fluid under reduced .pressure contin
165 by a line 191, connected via a drilled line 192 formed
ues 'from the line 223 via a drilled line in the valve spool
in the leftwardly moved valve spool 187, and thence via
to `a line 231 connected directly to the upper end of the
exhaust lines 193 and 194 to the sump 179.
At the completion of a selected table indexing move 30 cylinder 220, thus urging the piston 219 and pallet clamp
66 downwardly under low clamping pressure. Whenever
ment in response to controlled energization of motor 151,
219 the flow `of fluid ¿from «line 231 through a branch iline
a solenoid 195 to effect rightward movement of the valve
232 is prevented Iby ia leftwardly displaced valve spool 233
spool 187. As this occurs, iluid is exhausted from the
upper ends of the cylinders 164 and 165 by means of 35 of a lhigh pressure clamp valve 234. During low pressure
clamping, «a spring 235 operates to retain the valve spool
'the line 190; which is then connected via a drilled line
As soon as the pallet is properly located upon the table
53 in response to low pressure clamping, solenoid 228 iS
line 199 in the valve spool to the line 191 for supplying 40 de-energized and ia solenoid 238 associated with the valve
234 is energized to eiîect rightward movement of the valve
pressure fluid to the lower end of the cylinders 164 and
spool 233. Upon movement «of the valve spool L233 to its
165. Pressure fluid admitted to the cylinders below the
rightward position, ñuid under normally high pressure is
pistons 171, 172 eiîects downward movement of the table
transmitted fnom the main supply line 180 via a branch
53 thereby urging clutch teeth 157 into meshing engage
ment with clutch teeth 153 in fthe selected index position, 45 line 239, -and thence through a drilled line 240 formed iu
exhaust line 193. At the same time, iluid under pressure
is transmitted from the hydraulic line 183 vi-a a drilled
the rightwardly displaced valve spool 233 to the »branch
line 232, connected directly to the clamp supply line 231.
Thereupon, the piston 219 is urged ydownwardly under
To properly locate a pallet as it is urged into down
full clamping pressure to securely retain the pallet iu
ward clamping engagement with the table 53, as shown
in FIGS. 2, 5 and `9, the upper surface of the worktable 50 engagement with the supporting table 53 during subsequent
machining operations.
53 is provided with four Írusto-conically shaped locating
irrespective of whether the pallet is urged downwardly
pins 202 to 2615 inclusive. The tapered locating pins 202
eiîecting both a slight angular final positioning movement
and retaining the table in its selected indexed position.
under low or Ihigh clamping pressure, fluid is exhausted
to 205 inclusive are respectively disposed to cooperate
from the lower end of the cylinder 220 via a line 242 and
with four complementary tapered recesses formed in the
lower faces of linwardly extending ñanges 2118 and 2G19 55 thence through a drilled line in the rightward-ly moved
valve spool 226 that is connected to the exhaust line 1-93,
secured to the opposite side walls of the pallet. Two of
194.
the tapered pallet recesses i211 and 212 are clearly shown
To unclamp a pallet, .and elevate the clamp element
in FIG. 2, in a position to engage the cooperatively dis
66 to upward position dor the next shuttle movement, a
posed tapered table locating pins 202 and 293. As the
pallet 54 is urged downwardly into clamped engagement 60 solenoid 243 associated with the contro-l valve 227 is ener
gized. The valve spool 226 is urged leftwardly in re
with the table, the four locating pins carried by the table
sponse to energization of the solenoid 243 to connect the
engage the cooperating :tapered recesses presented in the
pressure supply line 223 via a cannelure 244 to the line
pallet to properly locate and support the pallet relative
to the table 53 and the cooperating tool spindle 34.
242. Fluid pressure ‘admitted to the lower end of the
As schematically represented in FIG. 9, the clamp ele 65 cylinder 220 effects upward movement orf the piston 219
ment 66 has been urged downwardly from its transfer
with a corresponding upward movement of the clamp1
position to securely clamp the cooperating pallet 54 to the
element 66 to align the way «surfaces presented thereby
table 53. To accomplish the required vertical pallet move
:?or a subsequent shuttle movement. With the pistou
ment, the underside of the clamp element 66 is secured to
moved upwardly, ñuid is exhausted from the upper end
the upper end of an axially movable support rod 214. The 70 of the cylinder 220 via the line 231 »and thence through
rod 214 is guided for vertical axial movement fby means «orf
a valve spool cannelure 245 to the exhaust line 193. Move
a bored opening formed in a transverse bearing plate 215
ment of the piston 219 upwardly causes a dog carried by
secured within the upper end of the tubular support mem
a lower extension of the piston rod 2-17 to actuate la switch
ber 161. The upper clamp rod 214 is secured by means
247.
Conversely, whenever the piston rod 217 is urged
75
of a pivotal coupling 216 to la piston rod 217 that is se~
3,099,873
15
downwardly to clamp the pallet to the table, las shown
in FIG. 9, a switch 248 is actuated.
At the completion of one program of machining opera
tions, a shuttle cycle can be initiated provding the table
53 has lbeen indexablly returned to its home position and
clamped; and providing the pallet clamp element 66 is
elevated to properly align the clamp ways with the c0
operating table ways. Assuming that this has been done,
leftvward reciprocable movement of the bar 88 With an
automatic return to its rightward parked position is ac~
oomplis‘hed by a control valve 249 which is interconnected
in the hydraulic control circuit shown in FIG. 9. In a
similar manner, in the event a rightward shuttle cycle is
required, a contnol valve 250 is operative to eiîect re
16
spool 263 is urged leftwardly to connect the pressure
supply line 180 to conduit 266 »for eíhecting counterclock~
wise rotation of the motor l122. Thereupon, the rack .124,
and bar 72 are moved in a leftward direction, with left
ward movement being stopped `in a parked position upon
actuation of the limit switch .148. The limit switch 148,
in turn, is connected to effect the required de-energization
of solenoid 269, permitting return movement of the valve
spool 263 to a resiliently biased neutral position inter
10 rupting the flow of pressure ñuid to either of the supply
conduits 264 or 266. ’
,
-One of the principal advantages of this invention is
the fact that either the tape reader 51 or the tape reader
52 is selectively connectable to actuate the numerical
quired operation of the hydraulic motor 122 for moving 15 control system diagrammatically illustrated in lFIG. lil,
the shuttle bar 72. Als Will hereinafter 1be more fully
for effecting a predetermined program of machining cycles
explained with reference to the electrical control circuit,
upon a particular workpiece. For example, as herein
FIG. 10, and block diagram, FIG. 1l, selected actuation
before explained, the tape reader 51 is connected to effect
of one vor another 'of the valves 249 and 250 is accom
a program of machining operations upon a workpiece
panied by la switching function for operatively connecting 20 carried by the pallet 54, FIG. l. After a workpiece car
one or another :of the tape readers 51 for 52 to control
riedfby the pallet 54 has been completely machined ac
machine movement for effecting a predetermined program
cording to information provided by the tape reader 51, a
of machining cycles in accordance with the actual work
diñ‘erently conñgured workpiece supported by the pallet
piece and pallet being moved into the operating station
55 is then moved into operating position upon the rotary
upon the indexable wlorktable 53.
25 table as the pallet 54 is moved leftwardly into the un
Upon energization of a solenoid 253 associated |with the
loading station. As a concomitant to movement of the
valve 249, a valve spool 254 is urged leftwardly, thereby
connecting the high pressure line 180 to supply ñuid to
pallet 55 and its associated workpiece into the operating
station, the tape reader 51, FIG. 1l, is disconnected from
a motor supply conduit 255. Pressure from the supply
the numerical control system and the tape reader 52 con
conduit 25S eifects the required counterclockwise rotation 30 nected to actuate the numerical control system for a
different predetermined program of machining operations,
of the motor 120 to eiïect leftward movement of the rack
according to the requirements of the workpiece carried
108 and shuttle bar 88. Whenever the motor 1120 is being
by the pallet 55. This novel arrangement for operatively
rotated in a counterclockwise direction, fluid is exhausted
interconnecting a particular tape reader capable of supply
therefrom via a conduit 256, and thence through a drilled
line in the leftwardly displaced valve spool 254 to the 35 ing coded yinformation according to the requirements of
-a particular associated workpiece provides a practical
main exhaust line 194. At the completion of a leftward
means for machining alternate workpieces within the
shuttle stroke of the bar y83, reverse limit switch 142 is
range of machine capacity.
actuated to elfect de-energization of thefsolenoid 253 and
Although the inventive concept is represented by a pre
energization of a solenoid 258 associated with the control
val-ve 249. ‘Energization of the solenoid 258, in turn, 40 ferred embodiment including the various structural views
effects rightward movement of the valve spool 254 to
and the schematic block diagram shown in lFIG. 1K1, an
other principal advantage of the invention is that all of
connect the main pressure supply line 180 via a drilled
valve spool line 259 to the motor supply conduit 256.
the components diagram-matically illustrated in FIG. l1
are commercially available and do not have to be spe
Pressure from the rline 256 effects clockwise rotation of
the rnotor 120 for returning the shuttle bar 88 to its 45 cially designed or manufactured to attain the greatly im
extreme right-ward parked position, the return dìow of
proved new results occurring from the practice of this
invention.
iluid from the motor 120 then being transmitted via a
The tape reader 51 is adapted to transmit digital infor
line 25S and a drilled line in the rightwardly displaced
valve spool 254 to the main exhaust line 194. Upon ar
mation yfrom moving tape (not shown) of the well known
rival of the shuttle bar 8S in its extreme rightward parked 50 punched type. =In this preferred embodiment of the in~
position, switch 145 is actuated to ell'ect de-energization
vention, the tape reader is provided with a plurality of
switches operative in `a binary code form by means of
of the solenoid 258 permitting resiliently biased return of
switch plungers engaging appropriately spaced holes in
the valve spool 254 to a central neutral position for inter
the punched tape, as the tape is mechanically advanced
Y rupting the transmission of pressure fluid or exhaust ñuid
to the motor supply lines 256, 255. The Iusual adjustable 55 relative to the reader. These readers are similar to read
ers used in conventional oñìce equipment. The punched
throttle control Valves (not shown) may be operatively
tape is the endless type and, Iirrespective of length, will be
interconnected in the motor supply lines 256 and 255 re
spectively.
_
A rightward shuttle movement of the bar 72 may be
disposed loosely in a plurality of superimposed loops with
in a carrier described commercially as a tumble-box.
`effected in a similar manner by energizing a solenoid 262 60 Thus, it is unnecessary to provide reversal of the tape
:for elïecting rightward movement of a valve spool 263
:associated with the control valve '250. Upon rightward
:movement of the valve spool .263, pressure fluid is trans
.-mitted `from the main supply line 1,80', lvia a drilled line '
spools at the completion of one pro-gram of machine
operations.
A n’
As shown in FIG. 11, tape readers 51 and 52 Iarér‘inter
connected in parallel between an energized input con
:in the valve spool to a motor supply line 2'64 for effecting 65 ductor 275 and a conductor 276 connectable to activate a
the necessary clockwise rotation ofthe motor 122 to move
code converter 277 that is operative, in turn, to convert
the shuttle bar 72 in a rightward direction. Fluid is ex
.information from the tape code’ to ‘deci-mal code; and in
hausted v-ia a line 266 connected via a valve spool line
well known manner, store this information in alternately
268 of the rightwardly moved valve spool to the exhaust
used registers in the form of sine-cosine voltage ratios for
-70 predeterminedly selected point to point positioning and
lines 193 and 194.
Reverse movement of the shuttle bar 72 upon comple
linear voltage ratios for velocity control. In addition to
tion of a rightward shuttle movement is effected by ac
converting and storing infomation for the X, Y andZ
tuation of the switch 147 connected to eifect de-energiza
axes, the code converter 277 is also operative to store
tion of the solenoid 262 and, simultaneously therewith,
energization of a solenoid 269. As this occurs, the valve
information in binary code form relative to the required
speed of the spindle 34; the selected indexed position of
3,099,873
17
the rotatable work supporting table 53; and, ‘as will here
inafter be more fully explained, for tool selection in a
modified form of the invention.
From the code converter 277, machine operating input
information is transmitted to a common trunk line 279
containing .a plurality of branch conductors connected to
different error operators.
To simplify the description, the five branch conductors
and error operators have been respectively designated by
common numerals 280 »and 281, each being followed by
an `appropriate letter suiiix to indicate the particular move
ment lbeing controlled. For example, the error operator
281X is operative -in well known manner to receive feed
back information via the lines ZSZX land 283X, respec
tively being operatively connected to supply feedback in 15
formation as to the position of the column 21 yalong the
X axis, and to supply information as to the velocity of the
column 21 as it -is being moved along the X saxis. To
provide accurate position feedback information, the line
18
402, the iive «branch conductors `designated by the common
numeral 402 being in turn connected to a trunk line 404
respectively connected to the tape readers 51 and 52.
Thus, whenever a particular series of programmed move
ments is completed, the error operators 281 are operable
via the trunk line 404 to provide Ia signal to whichever of
the tape readers 51 or S2 is connected to activate the sys
tem. The signal from the trunk line 404 provides a signal
to the tape readers for proceeding with the next block of
information »on whichever of the tapes is connected to
effect machine movements, this infomation then being
stored in properly decoded form in the code converter
277 for the next programmed series of machine move
ments.
In la similar manner, the live servo-amplifiers 292X,
Y, Z, S, ‘and T respectively are connected via branch con
ductors ito 1a common energized line `406. A disconnect
switch 407 is selectively movable to closed position in
a manner to transmit current from energized input line
282X «is connected to ia position indicator or reading head 20 409, 410 to «the 4lines 406 land 275 respectively.
As hereinbefore explained, the various 'elements des
287K which is secured to the column 21, as shown in
ignated lby common numerals in the block diagram, FIG.
FIGS. l ‘and ll. The reading head 287X is carried Áfor
lil, ‘are operative in similar manner toi perform identical
movement relative to la cooperating scale ZSSX which is
functions, «although the placement of various of these
secured directly to the frame ‘and connected to be ener
gized by means of conductors (not shown). The coop 25 ele-ments is slightly different in the associated machine
structure, .depending upon the particular structural com
erative coaction between the reading head 287X and the
ponent .it is associated with, the X axis, Y iaxis, Z axis,
scale ZSSX provides an accurate feedback signal to indi
spindle velocity, or table movement. For example, to
cate the exact position of the column along the «frame as
indicate ythe exact ver-tical position of the saddle 26, as
it is moved along the X axis. The ‘cooperating reading
head 2S7X and scale ZSSX are schematically represent-a 30 shown in FIG. l, the position indicator or reader 287Y
is `secured to the saddle 26 in !a manner to cooperate with
tive of well known commercially available units that are
the scale ZSSY which is secured :to «a vertical side face of
operative in the manner described.
the column 21. Likewise, »as shown in FIG. l, the posi
In a similar manner, to provide feedback information
»tion indicating head 2S7Z is secured directly to the trans
as to the velocity of the moving column 21 along the
cooperating frame, the line 283K is connected to receive 35 versely movable spindle head 29 in a manner to cooperate
with the horizontally Idisposed scale 288Z secured to a
information from a tachorneter 290X which is connected
side face of the saddle 26. As shown in FIGS. l, 2 and
to be driven by movement of the column 21. The error
operator ZSIX operates to produce voltage proportional to
5, the position indicating reading head 287T is secured
directly to the rotatable index table -53 in a manner to
the magnitude of the error, as well as polarity indicating
the direction of position error. The voltage ratios and 40 Acooperate with a circular position indicating scale 28'8T
that is secured to the central portion [of the machine frame
binary numbers stored 4in the code converter 277, irrespec
11S.
tive of whether they are operative to obtain position or
It will likewise be ‘apparent that the power translator
velocity input signals, yare compared to the corresponding
294T yassociated with the index table 53, is .constituted by
voltage ratios and binary numbers from the feedback con
ductors connected to the error operator ZSIX, with motion 45 «a gear drive, instead of ia screw «and nut mechanism as
shown for lthe X, Y »and Z axes. Further, the power trans
being stopped upon the occurrence of coincidence between
iator 294s associated with the drive for the spindle 34 is
the feedback supply and the code converter information.
constituted by interconnected gears iand the speed «trans
From the error operator 281X, command control infor
mission 38. inasmuch as the spindle 34
controlled
mation is transmitted to »actuate a servo-amplifier 292K
which is directly connected to accurately control the 50 ‘only for speed rate, no positioning feedback control is
velocity Vand extent of »movement of ia reversible power
actuator 293X. The power actuator 2'93X may comprise
either »a valve controlled hydraulically operated servo
motor (not shown) or 'an electric motor 45, as represented
necessary, rand none is shown in FIG. 11. The indexable
rtable 53, on the lother hand, requires »only ia point 4to point
positioning control from the position indicating head
287T via lthe feedback line 283T »to the error operator
in the drawings, which is `directly connected to drive the 55 281T. In the embodiment of the invention shown, no
velocity control is necessary for .the Worktabl'e 53 «as it
column moving translating screw 49. Thus, in the pre
is advanced -from selected index position to the next
ferred embodiment illustrated »in the drawings, the servo
required position.
ampliiier 292X is operative to cont-rol movement of the
As 'a prerequisite to effecting numerically controlled
motor 45 through armature or iield supply in well known
manner. The general arrangement for effecting move 60 indexable movement `of the table 53, it is necessary that
the table be first elevated to ra disengaged position. To
ment of »the column 211along the X axis is similar to that
«accomplish this, the tape signal for indexing is preceded
utilized for effecting required movement of the saddle 26
by yan unclamp signal fed into .the code converter 277, and
along the X axis, -spindle head 29 along the Z axis, velocity
thence transmitted via the trunk line 279 -to energize a
of the spindle 34 and positioning movement of the index
relay coil l4M, yas shown in FIG. ll. The relay coil 414
able rotary table 53.
is interconnected between the common signal supply con
As schematically represented in block diagram form, in
ductor 279 «and the energized 'line 406. Upon ener-gina.
FIG. 11, the power ‘actuator 293)( is vconnected to drive a
tion of 'the relay 414 in response to the appropriate input
translating mechanism 294X, which, in turn, is directly
signal, .the normally closed contact bars, as shown in
connected to a load 295X, in lthis case represented by
the :column 21. Actually, the translating mechanism 294K 70 FIG. l0 thereof »are moved to open position. Inasmuch
las the normally closed contact bars are interconnected
is represented as the cooperating screw 49 and nut 50, a1
in series between the solenoid 195 connected to energized
though any suitable equivalent may be utilized yfor these
particular elements.
conductor `417 ,and ia conductor I418 connected to ener
gized conductor 419, movement of the contact bars to
Each of the iive error operators designated by the com
mon numeral 231, is connected via a branch conductor 75 open position eñects de-energization of the solenoid 195.
19
3,099,873
20
Thereupon, fas show-n in FIG. 9, the valve spool 187 as
sociated with ltable clamp valve 1‘85 vis lbiased leftwardly
_connecting .the main pressure supply line 183 to the upper
ends of cylinders .164 ‘and 165 to eiiect upward movement
of the table 53 to disengaged position. As this occurs,
the lower support plate 163 `engages the »actuating plunger
of
switch 173, urging a normally open contact bar
into closed position, Ias shown in FIG. lll. Upon clos-ure
of fthe switch l173, the indexing control circuit from
reader 51 to the conductor 276.
associated switch contact bar to .closed position and to
the fbranch supply conductor 28M` in ‘a manner to trans
pallet 54 into the operating station, the unlatching coil
are operative to complete a circuit from'the tape reader
52 to the input conductor 276. At the same time, the
normally open contact bars 4261; are in open position
to preclude transmission of an operating signal 'from tape
To provide the operating conditions illustrated in FIG.
11, it will be assumed that the work supporting pallet 54
has been advanced into the operating station for the next
program of machining operations requiring connection of
supply conductor 279 ¿s .completed by movement of the 10 the tape reader 52. Concomitantly with advancement of
mit `the appropriate index movement signal «to the error
operator 281T. In response to the index signal, the drive
motor 151 Vis yenergized to effect a requisite rotational
movement of the .table 53 to its next selected index
position.
Upon »the arrival of the table 53 in selected position, a
positioning feedback signal from the reading head 287T
427, FIG. 10, is energized to return the contact bars
426L to open position and the contact bars 426U to nor
mally closed position. As the work pallet is then clamped
tothe surface of the Worktable 5G, FIG. 9, in response
to downward movement of the clamp actuating rod 214,
a pressure switch 430 is actuated to elîect closure of the
normally open contact bars associated with the switch
:is transmitted via feedback conductor 283T to the error 20 430, FIG. :11. As soon as the contact hars of the pres
sure switch 43(1are moved to closed position, an operat
operator 281T. Likewise, inasmuch las the table has com
ing circuit is completed from the energized input conduc
pleted its movement to the selected index position, the
tor 276 to activate the code converter 277, FIG. l1.
relay coil 414 is =de-ener»gized to effect return movement
Thus, actuation of the pressure switch 430 effects a ñnal
of the contact bars, FIG. 10, to their normally closed posi
tion, thus re-establishing lan energized circuit from con 25 operative connection which permits ‘automatic starting of
the tape reader 52 for activating the code converter 277
ductor 419 to energize the solenoid 195. Energization of
- to initiate the next program of machining operations re
solenoid 195, as hereinbefore explained, elïects rightward
quired by a workpiece carried yby the work supporting
movement of valve spool .187, FIG. 9, to reconnect .the
pallet '54. At the same time, coils 422 and Í423 are acti
main pressure supply ‘line 183 4to the hydraulic line 191
for effecting downward movement of the table 53 into 30 vated to control movement of the associated contact bars,
FIG. 10, as hereinbefore explained.
properly :clamped position upon the supporting frame 13.
In a similar manner, whenever the pallet 54 is moved
it will be apparent that the »table 53 can be repetitively
into the unloading station and pallet 55 is moved into the
advanced to fdiñïerent indexed positions in coordinated re
lationship .with vother required movements of the major
movable members in response to program input informa
rtion. Thus, for example, the table 53 may Ibe selectively
indexed to each of four different index stations, in each
of which a =diiîerent program of machining operations may
be automatically performed upon the particular face of
operating station, the latching coil 426 associated with
relay 425 is energized to »open contact bars 426U and
close the contact bars -42‘6L, thereby establishing an op
erative connection from tape reader 51 to the input con
ductor 275. Upon subsequent movement or“ the pallet
5S into clamped engagement upon the work supporting
the workpiece that is positioned -in operative relationship 40 table 53, the pressure switch 430 is again actuated to
eiîect closure `of the associated contact bars to connect
relative to the main tool spindle, 34, as shown in FIG. .1.
conductor 276 `for activating the code converter 277,
By means of interspersing idiiîerent degrees of indexing
thereby initiating the next program of machining opera
movement, in predetermined relationship to other ma
tions upon a workpiece carried ëby pallet 55.
chine movements, i-t will :be ‘apparent that an extremely
Wide variety of machining operations may be performed 45 The control circuit diagrammatically illustrated in FIG.
10 is operative to elïect alternative advancement of a
upon any workpiece that is advanced into the operating
work supporting pallet, 54 or 55, into the machine op
station by either the Work supporting pallet 54 or ‘55.
erating station, and simultaneously therewith, effect an
Whenever the machine is operating to» perform a pro
operative connection of one or «another of the tape
gram of machining operations in response to either the
tape reader,r51 or 52, signals are transmitted from the 50 readers, 51 yor 52, to initiate the next required program
of machining operations. The arrangement is such that
tape to the codeconverter 277 which is then operative to
separate single push button controls are respectively op
de-energize a relay 422 and energize a relay coil 423, as
erative to eiîect a required shuttle transfer movement of
shown in FIG. 11. Both of the relay coils 422 and 423
one or another of the pallets, with all subsequent move
are interconnected between conductors emanating from
the code converter 277 Y and conductors connected to the 55 ment of the shuttle bar, clamping of the work pallet, and
initiation of the appropriate tape reader controlled pro
energized line 406. As soon as a particular program of
machining operations is initiated, relay 423 is energized
gram of machining operations proceeding sequentially
and automatically in response to the single push -button
control. Likewise, at the start of a particular program
sociated therewith, PIG. 10, to open position. At the
same time, :de-energization of the relay coil 422 effects 60 of machining operations, one orV another of indicator
lights `44:8 or 449 is energized to signal the operator that
movement of normally yopen contact Ibars associated there
a program of machining operations upon a workpiece in
with to open position. Conversely, at the completion of
the operation has been completed, and the circuit can be
a particular program of machining Ioperations, signals are
transmitted to the code converter 277 which is then op
conditioned :for advancing the next uncompleted work
erative to effect energization of relay '422, relay 423y be
piece into the operating station =for a ditferent machining
ing retained in energized condition. Thereupon, the con
program. Thus, it will lbe apparent that machining op
tact bars associated with relay 422, FIG. 10, are moved
erations may be performed in relatively continuous fash
to closed position to condition the control circuit for a
ion upon workpieoes alternatively advanced into the op
subsequent machine program.
erating station, with a minimum of time being required
For connecting the required tape reader, 51 or 52, to 70 between programs upon the alternately presented work
control machine movements there is provided a latching
pieces. Therefore, for all practical purposes, it can be
type relay 425, FIGS. 10 and 11, that is operative to ef
said that the machine tool spindle is relatively continu
fect simultaneous movement of normally open contact
ously operable since unloading of a completed workpiece
bars 426L and normally closed contact bars 426U. As
and loading of an uncompleted workpiece is accomplished
_shown'in FIG. 111, the normally closed contact bars 426U 75 -in one tot `the unloading stations 57 or 58.
to effect movement of normally closed Contact bars as
3,099,873
The machine control system is so arranged that, at the
start of a working day, a selected one of the pallets, 54
or 55, may be advanced into the working station to begin
a series 4of machining operations upon a selected work
piece. At the completion of work on Ithe previous day,
it is contemplated that whichever of the pallets remains
in the operating station may be manually moved to its
associated unloading station. Manual movement of an
unloaded pallet lfrom the operating station to an unload
ing station would mean that Iboth of the pallets 54, 55
are in the unloading stations 5S, 57 yrespectively at the
start of the next working day. Thus, the starting shuttle
movement, after both pallets have been loaded with the
required workpieces, provides lfor moving only one of the
pallets into the operating station. For example, referring
to FIG. l, it Iwill now .be assumed that pallet 54 has been
moved manually to the unloading station 55, and pallet
55 is in the unloading station 57. The next shuttle move
22
to energize a relay 454. Energization of relay 454 also
eiiects movement of normally closed contact bars 454N
to open position, thus de-energizing high pressure clamp
ing solenoid 23S and low pressure clamping solenoid 22S.
Simultaneously, another circuit is completed via a branch
conductor I455 to energize the pallet unclamping solenoid
243, thus effecting movement of the pallet clamp 66
upwardly to a shuttle transfer position. Energization
oi the relay 454 eliects closure of contact bars 454M to
complete a holding circuit from the energized line 419
to a branch conductor 458 connected to the conductor
452 to retain the relay 454 in energized position during
the shuttle advancement.
Likewise, relay contact bars
454G are moved to closed position to establish a circuit
to conductor 456, and thence via closed contact bars 445G
to energize a shuttle start relay '460. Energization of the
relay 46d likewise effects closure of normally open con
tact bars 459i’ for activating the shuttle movement, which
then occurs, immediately upon movement of the pallet
nient then would provide yfor moving the pallet 54 from
clamp 66 to upper unclamped position eiîecting closure
unloading station 53 into the operating station 59, with 20
of switch 247.
pallet 55 being retained in unloading station 5’7 as shown
Closure of switch 1247 in turn completes a circuit from
in FIG. 1. All subsequent shuttle movements, after the
the energized line 419 through closed contact bars I'174P,
single starting movement, provide dior simultaneous ad
which are actuated to closed position whenever the table
vancement of `both pallets 54, 55 in coordinated relation
is in clamped engagement upon the support, and thence
ship with activation of the associated numerical control
through switch contact -bar 247, closed contact bars 460P
system, as hereinbefore explained.
and normally closed contact bars `444P to a conductor
To accomplish this, as shown .in the circuit diagram
459. From the conductor 459, the circuit continues
FIG. l0, there «are provided three separate push button
through the normally closed contact bar 1471’ of reverse
switches 434, 435 and 436 respectively. Whenever both
switch `147 to elîect energization of solenoid 262. As
30
of the pallets are in unloading stations, momentarily de
hereinbefore explained «with reference to FIG. 9, enengiza
pressing push button switch 434 conditions the circuit for
tion of solenoid 262 effects rightward movement of the
advancing the single pallet 54 into the operating station.
rack 124 and transfer bar 72 to effect a rightward move
With the circuit conditioned for advancing pallet 54 into
ment of the pallet 54 into operating position upon the
the operating station 59, momentarily depressing the cycle
worktable.
start switch 436 effects the initial, single shuttle movement
of pallet 54, with pallet 55 being retained in its unloading
Upon arrival ofthe pallet `54 in operating position upon
the index table, the rightward end of the rack ‘124 engages
station. After the machine has been started, as described,
the switch 147 to eiîect 4a reversal of movement of the
depressing .the push button switch 435 elîects a simultane
transfer bar 72. Activation of switch 147 effects move
ous shuttle movement of -both pallets, pallet 54 being
ment of contact bar 147P to open position thus de-ener
moved into unloading station 53 and pallet 55 being 40 »gizing the solenoid 262, and likewise effects closure of con
moved into ope-rating station 59. in other words, depress
tact lbar -147Q t-o elîect an immediate energization of the
ing the cycle start switch 436 to edect a single pallet
shuttle reverse solenoid 269 which «is operative to return
shuttle movement conditions the circuit for simultaneous
the bar to extreme left-ward parked position. This circuit
shuttle movement of both pallets, the direction of transfer
is completed ’from energized line 419, closed contact bar
Ithen being determined by depressing either the push but 45 ‘17d-P, closed switch contact bar 247 to a conductor 461
ton `»42,35 or the push button 436 as required.
and a conductor `452. Since switch 148 had been deactu
Power Íor energizing the circuit shown in FIG. l0 is
ated upon rightward movement of the shuttle 72 from
derived from a pair of energized line conductors 439, 449
parked position, the circuit continues from energized line
connected v-ia a disconnect switch 441 to energize line
462, closed contact bar =148Q of the deactuated switch
conductors V417, 419 respectively. With line conductors 50 148 to a conductor 463.
417, 419 energized, switch 434 is momentarily depressed
inasmuch as the shuttle reverse switch 147 is activated
`to complete a circuit via a conductor 443, normally closed
only momentarily to eiîect reversal, it will be 4apparent
contact bars 444A of a pallet reverse control relay 444
that the contact bars 147i?, 147Q associated therewith
to energize the coil of a relay 445. Energization of the
are immediately returned to the position indicated in FIG.
55
coil `445 completes a holding circuit from energized con
l0, once reversal has been started. Therefore, to elïect
ductor »419 via the upper closed contact bars 445B of
continued reverse movement of ,the bar Ito parked posi
relay l445 to the conductor 443. At the same time, lower
tion, `a shunt circuit is immediately established from ener
contact bars 445C of energized relay 445 are moved to
gized conductors 462 »and 463, closed contact lbar 44411,
open position to interrupt a circuit from energized con
and a conductor 465 to a conductor 466 for energizing
ductor 419 to a conductor 447, thereby de-energizing the 60 the relay r444 connected at its opposite terminal to ener
shuttle signal light 44S. Energization of the relay 445
likewise operates to urge contact bars 445G in closed posi
tion, and contact bars 445K in closed position during the
particular program cycle being initiated.
gized conductor 417.
Energizing relay 444, in turn,
elîeots movement of normally closed contact bar 444A
to open position to interrupt the initial control circuit,
thereby elfecting de-energization of the relay 445, »inter
To actually start the single shuttle movement, after ef 65 nupting the holding circuit »through contact bars 445B and
fecting energization of relay 445, the cycle star-t switch 436
permitting movement of contact bars 445C to normally
is momentarily depressed to complete a circuit from en
closed position. Indicator light 448 remains de-energized,
ergized line 415, normally closed contact bars of the relay
however, because normally closed contact bars 426C are
423, and thence via a conductor 451 and .through the
closed contact -bars y445K of energized relay 445 to a con 70 moved .to open position whenever the latch relay is held
open. To connect the appropriate tape reader for con
ductor `452. From the conductor 452, the circuit con
trolling the machining program, normally open contact
tinues through contact bars 457 which `are moved to
bars 4441 'are moved -to closed position -thus completing a
closed position by a cam (not shown) operable to in
circuit from energized line 419 to energize ‘the coil 426
dicate movement of the table to its home position; and
thence through normally closed contact bars 444K, 453K 75 of latching relay 425. Relay coil 426 operates to urge
3,099,873
23
24
normally open contact bars 4261;' to closed position com
54, and the code converter 277 operative to eiîect ener
pleting a circuit to energize signal light 449.l Energiza
tion of latching coil 426 effec-ts closure of contact bars
426L, FIG. 1l, Ifor connecting tape reader 51 to conduc
closure of the associated contact Ibars in line K, FIG. l0.
tor 276. Likewise, energization of relay 444 eiîects move
ment of normally closed contact Ibars 4441’ to open posi
-tion thus, precluding energization of shuttle solenoid 262
upon return movement of contact bar 147P to closed
giza-tion of the tape completed relay `422, thereby effecting
This condition existing, with :an uncompleted workpiece
loaded on the pallet 55, push button 435 is momentarily
depressed to complete a circuit from energized line 419
to energize the relay 473 having its opposite terminal
connected to the energized line `417. Conversely, in the.
event push button 435 is depressed during ‘a machine pro
position after reversed movement has been initiated.
Likewise, to continue reversal of shuttle bar movement, 10 gram to condition the :circuit for transfer, shuttle move
ment takes place automatically at the completion of the
energization of relay 444 effects closure of normally open
contact 'bars 444k completing -a shunt control circuit
program upon closure of contact bars 422, line K.
Energization of the relay `473 eiîects `closure of nor
from conductor 462 through the closed contact Ibars 444K
mally open contact Ibars 473B Iassociated therewith and
to conductors 464 and 465, thus retaining solenoid 269
and the relay 444 energized until the «transfer #bar 72 is 15 movement of normally closed contact bars ‘4731? to open
position. Closure of contact -bars 473B completes a hold
returned to its extreme leftward parked position.
ing circuit via the normally closed contact bars 453D
Upon arrival of the transfer Vbar 72 in its extreme lett
rto retain the relay 473 in energized condition. Likewise,
Ward position, switch 148 is again actuated to eiÍect move
energization of the rel-ay 473> eiîects closure of normally
ment of contact bar 148Q to upper open position, thus
open contact Ibars 473L to complete a circuit for ener
interrupting the circuit to solenoid 269 and relay 444
gizing «the shuttle start relay 454. This circuit is com
which Iare then tie-energized; the upper normally open con
tact `bar 148N associated with reverse shuttle switch 148 , pleted from energized conductor 419, via closed contact
'bars of energized relay 422, conductor 451, closed con
is urged into closed position completing a circuit from
-tact 'bars 473L, to the conductor 452. From the con
energized cond-uctor 419 to `a conductor 468.
During this initial single shuttle movement, the right 25 du-ctor1452 the circuit continues as hereinbefore explained
to energize the relay 454 and, simultaneously therewith,
transfer bar 88 is retained in extreme rightward parked
elfect energization of the pallet uncl-amping solenoid 243.
position to maintain the switch 145 actuated. Therefore,
Simultaneously with the energization of pallet unclamp-V
the circuit continues from conductor 468 via closed con
ing solenoid 243, normally closed contact bars 454N are
tact bar 145N to a conductor »469, land thence via nor
mally closed contact »bars 454N, through the normally 30 moved to open posi-tion lto interrupt the circuit to the
closed Contact I‘bar of deactuated switch 248 -to a con
pallet clamp solenoids 228, 233.
ductor 471 connected to effect energization of fthe low
Upon arrival of the pallet clamp 66 in upper un
clamped position, switch 247 is actuated to closed posi
tion, completing a circuit from energized conductor 419
pressure pallet clamping solenoid 228. As soon as the
pallet clamp 66 and pallet 54 are urged downwardly
under low clamping pressure in response to energization
of solenoid 228, las hereinbefore explained, switch 248
is actuated to upper closed position, thus yeifeoting ener
gization ofthe high pressure pallet clamping solenoid 238.
.
via the closed contact bars 174P to the conductor 461.
As this condition is being established, energization of
relay 454 effects closure of contact bars 454G to com
plete an energized circuit to conductor 475, which con
tinues via closed contact bars 426B and closed contact
Upon movement of contact bars 444I to closed posi
tion upon energization of relay 444, ya circuit is com 40 bars of energized relay coil `426 and thence through
closed contact bars 473H of energized relay 473y to
pleted from the energized conductor 419 to energize the
energize a shuttle start relay y477. Thereupon, contact
latching coil 426 of the latching relay 425, to effect move
bars 4778 are moved to closed position, completing a
ment of contact -bars 426U, FIG. ll, to open position
circuit from energized conductor 461, and thence via
and closure of contact bars 426L for connecting tape
reader 51 to conductor 276. Upon lfull pressure clamping 45 closed contact bar 4538 through the normally closed
contact bar 142S of reverse switch 142 to energize the
of the pallet 54 to the Worktable, pressure switch 430
left shuttle solenoid 253. Upon leftward movement of
is actuated to yeiiïect yclosure of the normally open contact
the associated shuttle bar, switch 145 is deactuated, per
Ibars associated therewith to closed position thus activat
mitting movement of contact bar 145T to move to closed
ing the code converter 277 for initiating a program of
ymachining operations.
50 position.
Upon arrival of the pallet 55 in operative re
lationship above the work-table 53, reverse switch 142
is momentarily actuated to move contact bar 1425 up
wardly to de-energize solenoid 253. At the same time,lower contact bar `142'1‘ is momentarily closed to corn
accordance with the particular pallet that is in the operat
ing' station -upon fthe worktable. For example, with 55 plete a circuit from closed contact bar 1451' through
closed contact bar 142T to conductors 478 and 479,
pallet 54 in operative position Iupon the worktable, push
for energizing reverse shuttle solenoid 25S and control
button switch `435 is operative to elîect a simultaneous
relay 453. Energization of relay 453 eñects movement
shuttle movement of the pallet 54 -to the unloading sta
of normally closed Contact bar 4538 to open position
tion and the pallet 55 in-to operating station. This is due
.to the fact -that the contact Ibars `associated with -tape 60 to prevent the re-energization of shuttle solenoid 253;
and, closure of contact bars 453U for establishing a
completed relay 422 are moved to energized closed posi
holding circuit to conductors 478, 479 and relay 453
tion upon the completion of a particular program of
until return rightward movement of the shuttle bar is
machining operations. Inasmuch as the control circuit
completed.
vfor effecting a leftward shuttle movement of pallet 54
65
Upon arrival of the shuttle bar 88 in its extreme,
and pallet 55 -is generally similar to that for elfecting
rightward parked position switch 145 is again actuated,
rightward movement of the pallet, it is not deemed neces
causing contact bar 145T to be moved to open position
sary to describe in detail the complete operation of the
thus
eiîecting de-energization of solenoid 258 and relay
control circuit for effecting a leftward shuttle movement.
453. Actuation of switch 145 likewise effects closure
However, it may -be :advantageous to explain Ithe operation
70 of the contact bar 145N to re-establish a circuit from
.of the shuttle initiating switches 434 and 435 after the
Yenergized conductor 419 to elîect sequential energization
cycle start switch 436 has ‘been depressed to initiate the
of the low pressure pallet clamping solenoid 228 and
single pallet shuttle movement at the start of a day.
238 as hereinbefore explained.
It will now be assumed that a machining program has
Whenever the pallet 55 is moved into ‘operating posi
After the initial, single shuttle movement has been com
pleted, the machine is conditioned for automatic opera
tion, at the completion of each machining program, in
been completed upon a workpiece carried by the pallet
tion upon the worktable 53, tape reader 52 is operatively
3,099,873
25
connected to conductor 276, FIG. 11.
This is accom
plished upon energization of relay 453 which effects
closure of contact bars 453i completing a circuit from
conductor 419 to energize the unlatching coil 427 of
relay 425, which effects return movement of normally
closed contact bars 426U to the position illustrated in
FIG. l1. As hereinbefore explained with reference to
shuttle movement of pallet S4 into the operating station,
clamping of the pallet 5S in like manner effects actuation
of pressure actuated switch 430 to effect closure of the l0
associated contact bars completing a circuit from con
ductor 276 to activate the code converter 277 for effect
26
ment, the cutting tool TSftB shown as being carried by
the spindle 34M in FIG. 12, will be transferred to the
pivotable tool storage holder S63, and the tool T54A will
be transferred into an operating position in the tool spm
le 34M in position for the next machining operation.
Likewise, at the completion of a tool changing move
ment, the tool holder 503 and tool change mechanism
504A are pivotably returned to parked position in a man
ner that the drum 502 may be indexably rotated to
properly position the next required tool adjacent the tool
change station. All tools are retained in releasable col
let holders of uniform diameter that are in turn releasa
bly retained in an associated tool storage socket 503 by
a detent (not shown). To simplify the description,
mechanism is operatively associated with the machine 15 reference numerals identify a tool and an associated col
let holder.
tool spindle, and is adapted to remove a tool carried by
The actual mode of operation and structural arrange
the spindle, replacing it with a different selected tool
ment of the parts required for effecting a tool change
according to the requirements of a particular program
cycle is illustrated in schematic form in FIG. 13. The
of machining operations. The tool change mechanism
is similar in general function and mode of operation to 20 various movable parts there shown are likewise presented
in coordinated relationship with the necessary power
the tool change mechanism fully disclosed and claimed
actuators and hydraulic circuit for effecting the com
in United States Patent No. 3,052,011, issued to Wallace
plete required sequence of movements constituting a tool
E. Brainard, John A. 'Hansen, Robert K. Sedgwick,
ing the next program of machining operations.
In a modified form of the invention, a tool change
change.
Charles B. Sipek and Hans J. Baechle, and entitled,
As shown in FIG. 13, the tool storage drum 502 is
“Machine Tool With A Mechanical Cutting Tool 25
journalled to rotate about a horizontally disposed shaft
Changer.” In the present invention, the structural ar
508 secured to the spindle head 29M. A ring gear 509
rangement and general principles of operation of the tool
carried within the tool storage drum 502 is engaged by
change mechanism are fully illustrated in simplified form
a pinion '510 secured to a shaft 512 driven by reversible
in FIGS. 12, 13, 14 and 15, the latter illustrating the
operative interconnection of the tool change mechanism 30 motor 513i. Energization of the motor 5.13 thus oper
ates to effect a selective indexable movement of the
in the numerical control system which is alternatively
tool storage drum 502 for positioning one or another of
operative in conjunction with the shuttle mechanism.
the tools carried thereby adjacent the tool change sta
inasmuch as the present invention is not directed to the
tion. To effect final positioning of the tool storage drum
tool change mechanism per se, a greatly simplified elec
tro-hydraulic control system is shown. This control, 35 502, as well as retain it in a selected index position,
there is provided an axially movable tapered index
FIGS. l13 and 14, is operative to effect a sequential oper
plunger 515 secured to a piston 516 constrained for
ation of the tool change mechanism which is illustrated
slidable movement within a hydraulic cylinder '517. As
as being capable of all essential movements in accord
shown in FIG. 13, hydraulic fluid admitted via the line
ance with the principles fully described in the afore
40 S18 is operative to urge the piston 516 inwardly to re
mentioned U.S. Patent 3,052,011.
tain the plunger 515 in engagement with an index notch
As shown in FIG. 12, a modiñed form of spindle
519, the particular engaged position shown being adapted
head 29M is slidably carried by the vertically movable
to retain the tubular storage socket 503 in proper posi
saddle 26 for selective movement relative thereto along
tion for a tool change movement.
the Z axis. A rotatable tool spindle 34M is thus carried
After the tool storage drum 502 is moved to a selected
for selective movement along three mutually perpen
position, initiation of a tool change cycle iirst causes the
dicular planes relative to the indexable worktable 53,
tool holder 503 and the tool change mechanism 504A
FIG. 1. As shown in FIG. l2, a selectively indexable
to pivot outwardly 90° to properly align the tool holder
tool storage drum 502 is rotatably supported by the
S03 in parallelism with the tool spindle 34M.
spindle head 29M. The tool storage drum 502 is pro
Pressure fluid for activating the plunger piston 516 is
vided with a plurality of pivotably mounted tool holders 50
or sockets 503, which are respectively shown in THG. 12
as carrying a plurality of diñerent types of cutting tools.
derived from a sump `521, being withdrawn by a pump
change movement, the tool T54A as well as the mech
a return line 531 connected by a valve spool groove to
522 connected to be driven by a motor 523` that is con
nected in well known manner to be energized by an elec
To facilitate the description, the tools carried by the
tric circuit (not shown). From the pump 522, the ñow
storage drum are identified by the reference numerals
T54 and T55 respectively, i.e. all tools to be used upon 55 of pressure fluid continues to a main pressure line 524
constituting a source of hydraulic pressure ñuid for all
the workpiece carried by the pallet 54 carrying the com
of
the solenoid controlled valves shown in FIG. 13. With
mon numeral 54 and all tools associated with the work
the index plunger 515 engaged, the valve 528 is actuated
piece carried by the pallet 55 carrying that common
as shown, the valve spool 529 being urged leftwardly
numeral. Prior to effecting an actual tool change, the
storage drum 502 is selectively indexed to position the 60 by a compression spring 530. With this condition exist
ing, fluid under pressure is transmitted from the supply
next required tool, in this case TS‘i-A, adjacent a tool
line 524 via a cannelure formed in the valve spool 529
change station. Next, in predetermined coordinated re
to the line `518 connected to effect inward movement of
lationship with the machining program then in progress,
the piston 516. At the same time, pressure fluid is ex
the tool change mechanism 504A is selectively activated to
effect the required tool change. At the start of the tool 65 hausted from the opposite inner end of the cylinder by
a main exhaust line 532. connected to return fluid to
anism 504A is pivoted from a phantom line position,
the sump 521. Prior to effecting a selected index move
shown in FIG. 12, outwardly to the actual tool change
ment of the tool storage drum 502, it is necessary to
positions shown in full line in FIG. l2. As this occurs,
the tool TSßiA is aligned in axial parallelism with the 70 energize a solenoid S33 effecting rightward movement
of the Valve spool '529 in opposition to the spring 530.
tool T5413 then carried by the tool spindle. To effect the
Upon rightward movement of the valve spool 529, the
actual tool change movement, the mechanism 504A is
pressure supply line 524 is connected via a valve spool
provided with a tool change arm ‘504 that is carried for
groove 535 to the line S31 thus effecting outward move
both pivotable and axial movement about a horizontal
axis. At the completion of a required tool change move 75 ment of the piston 516 to withdraw the index plunger
3,099,873
2?
515 from engagement with one or another of the notches
519. Upon outward movement of the piston 516, pres
sure fluid is then exhausted via the line 51S, connected
by a valve spool groove 536 to the main eúaust line 532,
Upon the admission of hydraulic pressure iiuid from
line 545 to the cylinder 546, a piston 547 is urged left
wardly to effect corresponding leftward movement of
piston rod 548, provided on its inner side with rack teeth
(not shown).
Leftward movement of the piston rod
rack 548 effects clockwise rotation of a cooperatively
meshing rotatable pinion '549 connected to effect simul
taneous rightward movement of an axially slidable rack
550. Since lthe tool holder 503 is pivotably supported
by a radially extending arm 551 carried by the tool
storage drum 502, the tool holder is pivoted outwardly
to the position shown in FIG. 13 upon rightward move
ment of the rack 550.
Y
Clockwise rotation of pinion 549, upon leftward move
ment of piston 547, effects a corresponding clockwise
rotation of shaft 552 and a pinion 553. The upper pin
ion 553 engages a gear segment 554 provided with a
laterally extending arm 555- that is pivotably secured to
a lever arm 556. At its opposite end the lever arm 5'56
opposition »to reduced pressure flow via line 583. Pres
sure fluid 'from line 583, however, continues through a
port formed in the lower Wall 58S of .the hollow piston
`577 and ñows into the lower end of an inner cylinder
586 formed within the piston 577. As lthis happens,
pressure ñuid introduced in the lower end of cylinder 586
urges a piston 589 upwardly to its limit of movement in
the cooperating cylinder 586. Upward movement of the
piston '589 displaces fluid vi-a a line 590 which is con
nected by a groove 5911 Iformed in a valve spool 592 of a
valve 593 to a main exhaust line 532.
Upward movement of piston 589 effects corresponding
upward movement :of a piston rod 595 and a rack S96.
Upward movement tof the rack 596 effects rotation of an
intcrmeshing pinion 597 in a clockwise direction, effect
ing like rotation of a spline shañt 598 secured thereto
and a sequence control cam 599.
The spline shaft 598
engages an internally splined tubular sleeve 602 that is
journalled to rotate within a horizontally disposed cylin
drical opening provided lin a .fforwand extension 603 inte
grally formed with the rotatable tubular support mem
Ibcr '560. At its forward end, the internally splined
y sleeve 602 is secured to the central portion of the tool
is secured to a pivot pin S59 extending upwardly from
change arm 504. Initial `rotation of the tool change
a main Vtubular support 560. Thus, clockwise rotation 25 arm 504, in a clockwise direction, in response to move
of pinion 553 effects counterclockwise rotation of seg
ment of piston 589 is arranged to be suñicient to etîect
ment 554 which, in turn, operates to urge lever arm
an operative engagement of the tool change arm wit-h
556 leftwardly to rotate the entire tubular support 560
tool holders kTS‘EA and T54B respectively carried lby
outwardly 90°. The tubular support 560 is rotatably
the tool storage socket 503 and the tool spindle 34M.
journalled at its opposite ends about concentric axes by 30 The original positions in which `the tool holders T54A
coacting portions of the spindle head 29M.
and T54B are positioned at the time they are respectively
The action of the reciprocable racks 548, 550 in ef
engaged by 90° movement of the tool change arm 505,
fecting pivotable movement of the toool Astorage socket
are indicated in FIG. 12.
503 may be better illustrated by reference to tool holder
To support each tool, both during withdrawal and a
503A, FIG. 13, which is shown in its normal parked
subsequent tool change movement, the tool change arm
position, i.e. with the tool axis parallel to the axis of
`§04- is provided at its opposite ends with circular open
the shaft 508. As there indicated, each of the tool hold
ings 506 and 507 that are open, in opposite directions,
ers, such .as 503A, is provided on its periphery with
to eiïect engagement with the tool holders for the tools
cams 561 and 562 respectively. The rearward cam 561
T54A and T54B respectively. For retaining the tool
is engaged by the rightwardly moving rack y550 to elïect 40 holder rtightly during a change movement, each of the
outward pivotable movement of the tool storage socket
openings is provided with a spring »biased roller detent
503; and, the forward cam 562 is engaged upon right
603 as indicated in íFIG. 13. ’I'he detent 603 is disposed
ward movement of the piston rod rack 548, whenever
to move radially with respect to the axis of the tool sup
the tool is returned to its storage position. At the com
ported Within the circular opening 506. In a similar
pletion of an outward pivotable movement of the tool 45 manner, the circular opening 507 formed at the opposite
change arm support 560 and tool storage socket 503,
end of the tool change arm 504 is likewise provided with
ñuid is exhausted from the opposite end of the cylinder
a spring =biased idetent (not- shown).
.
.546 via a return line 565 connected by a valve spool
»Only two of the complete sequence of events required
groove to the main exhaust line S32. To simplify the
in a tool chan-ge are shown in FIG. 13. The tool change
description, al1 necessary movements accompanying a 50 arm 504 is shown in a rvertical, parked or Zero (0°) posi
tool change will be described in the sequence in which
tion. Next, in phantom lines, the arm is represented in
_they occur.
its outer position, after a 270° rotation to position the
Upon arrival of the tool change »arm in outward posi
tools for reinsertion.
,
'
'
tion, an abutment 565 secured to the arm 556 actuates a
Intermediate the parked position indicated in FIG. 13
normally open switch 566 to initiate the next movement. 55 and the phantom line position, two additional move
Energization >of the switch 566 `operates to eiîect ener
ments are required. During the original 90° of clock
gization of-a pair of solenoids 568 and '569 respectively
associated with control valves 570 and '571 respectively.
Energization of solenoid ‘569 eíîects rightward movement
of a valve spool 573, thereby connecting the main pres
sure supply -line 524 via a valve spool :groove 574 to a
supply line 575 connected at its opposite end to supply
pressure iiuid to a cylinder 576.
With pressure ñuid ad
mitted within Icylinder Á576, a .slidable hollow piston 577
is retained in `downward position -within the cooperating
cylinder. At the same time, energization of solenoid
568 eíîects rightward movement of valve spool 581 ,to
connect the main pressure »supply line 524 Ivia 4a valve
wise rotational movement of the tool arm 504, the actuaft
in-g roller of a normally open switch 612 -is engaged by
a dwell portion 613 of the control cam 599 which is
rotating in a clockwise direction.
Upon arrival of the
cam `599 and tool arm 504 in the 90° position, »the actuat
ing roller of switch 612 is engaged by the enlarged pe
riphery or land 614 `of the cam 599. Actuation of switch
612 to closed position upon arrival of the arm 50‘4 in
the 90° position, in turn; operates to eñect unclamping
movement of a clamp mechanism 617 and forward move
ment of the tool change arm 504. The clamp mecha
nism 617 is provided with a horizontal slot, and a tapered
forward =end 618 disposed to coact with a complementary
spool groove 582 to -a supply -line ‘583.
A regulating valve ‘534 in .the line ‘58,3 is operative to 70 taper presente-d within the forward end of the tool spindle
reduce the pressure through -the line Which -is connected
34M. Thus, upon forward movement of «the clamp
to a port ¿formed in the lower end of the Wall ‘for the
mechanism, `a tool is unclamped from engagement with
enlarged cylinder S76. With pressure »from line 575
the tool spindle 34M. Conversely, upon being urged
admitted to the upper end of the cylinder 576, however,
rearwardly, the tapered ‘forward shoulder `61,8 is en
vthe piston V577 is retained in its downward position in 75 gaged Iby the complementary spindle taper in a manner
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