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Патент USA US3060655

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Oct. 30, 1962
3,060,647
A. H. DALL ETAL
PHASE-OUT DEVICE FOR GRINDING MACHINE
Filed March 31, 1961
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Oct. 30, 1962
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A. H. DALL ETAL
PHASE-OUT DEVICE FOR GRINDING MACHINE
Filed March 31, 1961
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Oct. 30, 1962
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Filed March 31, 1961
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Oct. 30, 1962
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PHASE-OUT DEVICE FOR GRINDING MACHINE
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Filed March 51, 1961
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Oct. 30, 1962
3,060,647
A. H. DALL ETAL
PHASE-OUT DEVICE FOR GRINDING MACHINE
Filed March 31, 1961
8 Sheets-Sheet 8
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United States Patent () ”
3,060,647
Patented Oct. 30, 1962
2
R
apparent from the following description, the invention
3,060,647
PHASE-OUT DEVICE FOR GRINDING MACHINE
Albert H. Dali and George L. Grove, Cincinnati, Ohio,
assignors to The Cincinnati Milling Machine Co., Cin
cinnati, Ohio, a corporation of Ohio
Filed Mar. 31, 1961, Ser. No. 99,797
9 Claims. (Cl. 51-165)
includes certain novel features of construction and com
binations of parts, the essential elements of which are set
forth in the appended claims, and a preferred form or
embodiment of which will hereinafter be described with
reference to the drawings which accompany and form
a part of this speci?cation.
In the drawings:
FIG. 1 is a front view of a grinding machine incorpo
This invention relates to a wheel truing mechanism 10 rating the teachings of the present invention.
for use with precision grinding machines, and, more par
ticularly, to an apparatus for keeping the wheel truing
tool in phase with the wear compensating mechanism of
the grinding machine so that after a truing operation,
the location of the grinding wheel relative to the work
supporting means will be such as to cause the machine
to grind parts of the correct diameter.
An important feature of present day precision grinding
FIG. 2 is a cross-sectional view taken along the line
2-2 in FIG. 6.
FIG. 3 is a transverse section through the truing tool
for the grinding wheel.
FIG. 4 is a detailed view, partially in cross section,
showing the feed mechanism for the truing tool.
FIG. 5 is a diagrammatic view of the hydraulic circuit
of the wheel truing apparatus.
FIG. 6 is a front elevation of a portion of the machine
machine resides in the automatic truing apparatus which
maintains a sharp, accurate cutting face on the grinding 20 shown in ‘FIG. 1 with parts broken away to show the
internal construction.
wheels of such machines. In keeping with the trend to
FIG. 7 is a diagrammatic view of the hydraulic circuit
ward more and more automated equipment, it is now
for the wheel slide feed mechanism.
common practice to provide automatic controls for such
FIG. 8 is a cross-sectional view taken along the line
machines which will cause the automatic grinding process
to be stopped after a predetermined number of parts have 25 S—8 in FIG. 6.
FIG. 9 is a cross-sectional view taken along the line
been ground and thereupon initiate truing of the grind
9—9 in FIG. 6.
ing wheel. After the wheel has been trued, the automatic
FIGS. 10a and 10b constitute a wiring diagram of the
grinding process once again will be resumed and the
electrical control circuits for the machine shown herein.
parts will continue to be ground until the next wheel
FIG. 11 is a schematic view illustrating the principle
truing operation is initiated. The point where the grind
of operation of the phase-out mechanism.
ing cycle stops and the truing cycle begins is ordinarily
In the detailed speci?cation to follow, similar refer
signaled by a counter which is preset in accordance with: p
ence characters designate similar or identical elements
the number of parts to be ground between truing cycles.
and portions throughout the speci?cation and throughout
When the predetermined number of parts have been
ground, a signal from the counter stops the grinding proc 35 the different views of the drawings.
ess and starts the automatic truing cycle.
On each pass
In FIG. 1 is shown a centerless grinding machine of
of the truing tool across the grinding wheel, a predeter-.» ‘
a known type to which the new phase-out device has been
mined amount of material is removed therefrom and the
diameter of the wheel is thereby reduced. Accordingly, a
applied. It will be appreciated, however, as the descrip
tion proceeds, that the present invention might equally
compensating mechanism is ordinarily provided to cause 40 well be applied to other known forms of grinders of
either centerless or center type construction. As shown
the grinding wheel to be moved toward the work through
a distance equal to the amount of material removed from‘ ~ in FIG. 1, the grinder is provided with a base 12 upon
which is journaled a grinding wheel 13 enclosed within
the wheel so that when the grinding operation is resumed,
a wheel guard 14. The grinding wheel is arranged to
the parts will be ground to the correct diameter. At the
conclusion of the truing cycle, a signal is given to restart 45 be driven by a motor (not shown) also supported on the
base 12. A regulating wheel 15 is supported for rota
the grinding process. This otherwise straight forward
procedure is complicated, however, by the fact that it is‘ - tion about its axis on a wheel slide ‘16 which is mounted
for sliding movement on a lower slide 17. This slide has
usually necessary to compensate for wheel wear between
secured thereto a work-rest blade 18 which serves as a
truing cycles in order to prevent over-size parts. In other
words, the wheel slide is moved independently of the 50 support for a workpiece 19 disposed between the grind
ing wheel 13 and the regulating wheel 15. A drive motor
truing tool during the grinding process so that the tool
(not shown) is provided for driving the regulating wheel
and slide tend to get “out of phase” and cause the ma
15 in a known manner.
chine to produce undersized parts when grinding is re
For set up purposes the wheel slide is provided with
sumed. The purpose of the present invention is to pro
vide a simple and practical device for bringing the truing 55 a handwheel 21 which is adapted to rotate a nut ro
tatably journaled in the slide and meshing with a feed
tool and wheel slide back into phase during the automatic
truing cycle whereby parts of the correct diameter will . screw. This mechanism is fully explained and described
in U.S. Patent No. 2,709,877 to which reference may be
be ground by the machine after the wheel has been
had for a complete disclosure of this portion of the
trued.
Accordingly, it is an object of the present invention 60 mechanism.
After a predetermined number of workpieces have been
to provide a new and improved phase-out device for pre
ground by the machine, it is necessary to true the grind
cision grinding machine.
ing wheel and, for this purpose, a truing mechanism 22
Another object of the invention is to provide a simple
has been provided. This mechanism, which is supported
mechanical device for bringing the truing tool of a grind
ing machine back into phase with the wheel slide during 65 on a bracket 23 mounted on the base of the machine,
is fully automatic in operation and may be of the type
the course of an automatic truing cycle.
disclosed in U.S. Patent No. 2,937,639 to which reference
Another object of the invention is to provide a new
is made for a detailed disclosure thereof. In the present
coarse-?ne compensating mechanism for grinding ma
drawings only so much of the automatic truing mecha
chines in which the amount of coarse compensation given
the wheel slide is in complementary relationship to the 70 nism is shown as is necessary for a complete understand
ing of the present invention. In using this mechanism,
number of ?ne compensations introduced therein.
the operator determines the number of truing passes to
With these and other objects in view, which will become
8,060,647
3
Li.
be made by the truing tool across the face of the grind
a return line 61. The motor 35 will thereby be rotated
in a direction to drive the carriage away from home posi
ing wheel and sets this number on a dial 24 of a counter
25 contained in an electrical cabinet 26. The automatic
truing cycle may then be initiated by depressing a Truing
Start push button SP3 to cause the diamond tipped truing
tool to traverse back and forth across the grinding wheel
13 with automatic advance of the diamond on each pass
until the selected number of passes have been made. In
tion, i.e., the position in which a dog 64 (FIG. 3) secured
to an elongated bar 65 mounted on the carriage 32 is
in contact with the arm '66 of a limit switch 31.3. This
limit switch and a companion limit switch 2LS are mounted
in a housing 67 attached to the wheel guard 14.
Referring again to FIG. 5, if solenoid 4SOL is ener
the present disclosure, the counter usually provided for
gized in place of solenoid 3SOL, the spool 52 will be
counting the number of workpieces ground between truing 10 shifted to the right and cause spool 56 to be shifted
operations has not been shown though it will be appre
ciated that a signal from such a counter might be utilized
in accordance with the prior art teachings instead of the
push button SPB.
to the
motor
motor
in the
left thereby connecting a pressure port 68 to the
line 45 and connecting the return port 60 to the
line 46. This will cause the motor 35 to rotate
opposite direction and move the carriage from a
Referring now to FIG. 3 of the drawings, the diamond 15 reversal position, as represented by engagement of a dog
is suitably mounted on the forward end of a truing bar
69 (FIG. 3) with the arm 70 of limit switch ZLS, toward
30 which is supported for longitudinal sliding movement
home position. The return line 61 is connected by a line
Within a tubular housing 31 by means of suitable bearing
73 with a pressure reducing valve 74. This valve con
surfaces provided at the ends of the housing. The hous
tains a sliding plunger 75 having a transverse bore 76
ing, in turn, is mounted for longitudinal shifting move 20 and a longitudinal bore 77 communicatively connected
ment within a traversing carriage 32 by means of balls
therewith. The bore 77 extends to the bottom of the
33 running in tracks provided on the housing 31 and
plunger 75 and transmits ?uid to a chamber 78 provided
on the carriage 32.
in the bottom of the valve. The pressure of the ?uid
Traversing movement of the carriage 32 on the bracket
in the chamber 78 will tend to raise the plunger against
23 is eifected by means of a lead screw 34 (FIG. 5) which 25 the urgency of a compression spring 79, this upward move
is driven by a hydraulic motor 35 and meshes with a nut
ment of the plunger tending to cut off the port to which
in the carriage.
The advance of the truing tool toward the grinding
wheel prior to each truing pass is effected by means of
a feed screw 36 which, when rotated, causes feeding move
ment of the truing bar 30 (FIG. 3) relative to the hous
ing 31. For the purposes of the present invention, the
housing 31 may be considered as ?xed with respect to
the carriage 32. The means for advancing the truing bar
the line 73 is connected. Accordingly, the plunger will
be stabilized when the pressure in the chamber 78 equals
the pressure acting on the top of the plunger. Since the
30 downward force acting on the plunger is constant, the
pressure in chamber 78 will also remain constant and a
constant pressure will thereby be maintained at the outlet
port 88. This port is connected by a line 81 with a
rate valve 82 which may be adjusted by rotating a knob
by means of the feed screw 36 will hereinafter be de 35 83 to vary the amount of oil permitted to ?ow through
scribed.
an outlet port 84 on the valve. This port is connected
The hydraulic circuit for effecting traversing movement
by a line 85 with a relief valve 86 which is connected to
of the carriage 32 is shown in FIG. 5 of the drawings.
the exhaust line 44. The pressure in the line 85 will
As illustrated therein, hydraulic ?uid is delivered to a
thereby be maintained constant in accordance with the
pressure line 40‘ by a pump 41 driven by an electric 40 setting of the relief valve 86. Hence, ?uid admitted to
motor (not shown). The pump draws ?uid out of a
the top of the pressure reducing valve 74 through a line
reservoir 42 and delivers it to the pressure line 40 at
87 will also be maintained constant. The pressure thus
a constant pressure determined by the setting of a relief
provided on top of the plunger 75 will be added to that
valve ‘43 which discharges excess ?uid back into the re
of the spring 79 and will improve the linearity of the
servoir 42. An exhaust line 44 returns ?uid to the reser 45 valve 74. Hence, by manipulation of knob 83 of rate
voir from the various hydraulic components contained in
valve 82, the feed rate of the truing tool across the grind
the circuit.
ing wheel may be adjusted as desired.
As mentioned above, the feed screw 34 which traverses
The hydraulic circuit includes a rapid traverse valve
the carriage 32 back and forth with respect to the grind
90 which is effective, when operated, to bypass the rate
ing wheel 13, is driven by a hydraulic motor 35. This 50 valve and connect the return line 61 directly to the ex
motor is connected by hydraulic lines 45 and 46 to a
haust line 44-. This valve is provided with a spool 91
reversing valve 47. This valve is operated by a solenoid
which is normally held in its left hand position as shown
valve 48 which valves ?uid under pressure to the ends
in FIG. 5 by a compression spring 92. In this position
of the reversing valve through lines 49 and 50 thereby
of the spool, a line 93 connected to the return line 61
shifting the spool of the latter valve in one direction or 55 is blocked by a land on the spool. However, when a
the other.
solenoid SSOL is energized, the spool 91 will be moved
The pilot valve 48 contains a spool 52 which is held
to the right against the urgency of spring 92 and the line
in a centered position within the valve body by means of
93 will be communicatively connected with the exhaust
compression springs 53 and centralizing washers 54. The
line 44 thereby bypassing the rate valve and permitting
valve is provided with a centrally disposed pressure port 60 the motor 35 to run at full speed.
which is connected to the pressure line 40, and with a
Automatic advance of the truing bar 30 is effected by
pair of exhaust ports located on opposite sides of the
means of a pawl and ratchet mechanism illustrated in
pressure port which are connected with the exhaust line
FIG. 4 of the drawings. As therein shown, a piston 95
44 through a check valve 55. Hence, when the solenoid
is slidably received within a cylinder 96 provided in the
3SOL is energized, the spool 52 will be shifted to the 65 base portion 97 of a housing 98 secured to the outer end
left, as viewed in FIG. 5, thereby connecting the line
of the truing bar 30. As shown in FIG. 4, the right hand
49 with the pressure line 40, and the line 50 with the
end of the cylinder 96 is closed by a cap 99 while the left
exhaust line 44. This will cause pressure to be applied
hand end of the cylinder is closed by a bushing 100‘ which
to the left hand end of the reversing valve 47 and will
is adjustably secured to the housing 98 by cap screws
connect the right hand end of this valve to exhaust. As 70 101 and set screws 102. The bushing 100 is provided
a result, a spool 56 which is normally held in a centered
position by compression springs 57 and centralizing wash
ers ‘58, will be shifted to the right thereby connecting a
‘pressure port '59 with the motor line 46, and connecting
with an axial bore for receiving the stem 103 of a dia
mond advance selector knob 104 which may be turned
to any one of four positions to select different amounts
of diamond advance.
As shown in FIG. 4, the right
the motor line 45 with a port 60 which is connected to 75 hand end of the stem 103 serves as a stop to limit left hand
‘3,060,647
5
movement of the piston 95 while the cap 99 serves as
a stop to limit right hand movement of the piston within
the cylinder. The piston is bored to receive a compres
sion spring 105 which presses on the end of the stem 103
and thereby urges a pin 106 projecting radially from the
stem into engagement with the inner edge of the bushing
1110. The edge of the bushing is provided with four
notches 107 of varying depth for receiving the pin 106.
Hence, by pressing in on the knob 104 and turning the
same, any one of the notches 107 may be selected to
receive the pin 1116, thereby providing four different de
grees of adjustment of the inner end of the stem 86
relative to the left hand end of piston 95.
Thus, four different strokes of movement are permitted
the piston, which strokes are effected under hydraulic
pressure controlled by a valve located in the bottom por
tion 97 of the housing 98. This valve includes a spool
110 which is slidably received in a cylindrical bore pro
vided in the base portion 97 and which is urged toward
6
the knob 123 is turned 180 degrees, the lug 124- Will ele
vate the pawl and disengage it from the teeth of the ratchet
wheel 117. At the same time, the upper edge of the pawl
will engage the plunger of a limit switch \1LS mounted
on a bracket in the top of the housing 98 and, through
means shown in the wiring diagram in FIGS. 10a and
10b, will disable the automatic truing control circuit.
In setting up the machine for a particular grinding op
eration, the wheel slide 16 is clamped to the lower slide 17
by tightening a clamp 21} (FIG. 1) on the side of the
wheel slide. At the same time, a clamp 27 is loosened to
permit the lower slide to move with respect to the base
12. The hand wheel 21 is then turned to feed the wheel
slide 16 and lower slide 117 as a unit along the feed screw
until the workrest blade 18 is brought into the proper
position. The clamp 27 is then tightened and the clamp
29 is loosened to permit the desired setting of the regu
lating wheel independently of the workrest blade 18. A
clamp 128 (FIG. 1) is then tightened to clamp the nut
the right ‘by a compression spring 111. The spool is 20 with respect to the wheel slide 16 as explained in US.
Patent No. 2,709,877 to thereby enable feeding move
thereby maintained with its right hand end bearing against
ment of the wheel slide to be effected by rotation of the
the inner edge of a bushing 112 located in the end of the
feed screw.
cylindrical bore. An intermediate portion of the bore is
As shown in FIG. 6, the machine is preferably provided
connected by a channel 113 with the right hand end
with a walking beam type of infeed mechanism as dis
of the cylinder ‘96. When the spool 1:19 is in the position
closed in US. Patent ‘No. 2,718,101. As shown herein,
shown in FIG. 4, this channel is communicatively con
the walking beam 129 is connected by pivot pins 1.130 and
nected with the exhaust line 44 (FIG. 5), thereby per
131 to a sleeve 134, the corresponding parts in US. Patent
mitting the spring 105 to move the piston 95 to the limit
No. 2,718,101 being numbered 29, 30, 31 and 34. vIn that
of its movement in the right hand direction. However,
patent however the sleeve is pinned to the feed screw here
when solenoid 6SOL is energized, a plunger 114 passing
in numbered 135, whereas in the present machine the
hrough a bore in the bushing 1112 will be projected out
sleeve is journaled for rotation on the feed screw by
wardly against the right hand end of the spool 110 and
means of a thrust bearing 136 and a combined radial and
‘shift the latter to the left against the force of the spring
thrust bearing 137. These bearings are interposed be
111. With the spool in this position, the channel ‘113 will
tween the feed screw 135 and the sleeve 134 and are held
be communicatively connected with the pressure line 40
(FIG. 5) whereby hydraulic fluid under pressure will be
admitted to the right hand end of the cylinder 96 thereby
driving the piston 95 to the left. When the solenoid is
deenergized, the spring 111 will return the spool to the
in place between a nut i138 threaded on the feed screw and
a shoulder >137 likewise provided on the feed screw.
As explained in US. Patent No. 2,718,101 the walking
beam operates to bodily move the feed screw in an axial
position shown in FIG. 4 thereby again connecting the 40 direction to effect rapid traverse movement of the wheel
right hand end of the cylinder 96 with the exhaust line
44 whereupon the spring 105 will return the piston to the
position shown. As heretofore mentioned, the stroke
of the piston is determined by the setting of the selector
knob 104 so that different degrees of diamond advance
may be obtained.
The upper edge of the piston 95 is provided with rack
teeth which mesh with the teeth of a spur gear 115, the
upper portion of which is removed to provide a seat for a
block 116 which is screwed fast to the gear. Situated
slide for infeed movement of the regulating wheel with
respect to the workpieces being ground.
Since in the present embodiment, the feed screw 135 is
journaled for rotation with respect to the walking beam
129, it is desirable for setup purposes to provide a clamp
screw 139 threaded into a tapped hole in pivot pin 130‘ for
preventing rotation of the lead screw when the clamp
screw is tightened. This is for the purpose of preventing
rotation of the feed screw when the handwheel 21 is
manipulated to rotate the nut during the setup of the ma
adjacent the gear 115, which is freely rotatable on the
chine. In the following description of the compensating
feed screw 36, is a ratchet wheel 117 which is pinned
to the screw 36. The wheel ‘117 is arranged to be driven
by a pawl 118 which is pivoted on a stud 119 carried by
the block 116. The pawl is urged in a clockwise direc
feed mechanism for the wheel slide 16 it will be assumed
that the machine has been properly setup and that the
tion about the stud 119 by a compression spring 120' in
terposed between the block and the pawl thereby engaging
the pawl with the teeth of the ratchet wheel 117. Hence,
128 (FIG. 1) has been tightened to prevent rotation of
when the piston 95 is driven to the left as viewed in FIG.
clamp screw 139 has been loosened so as to permit rotation
of the feed screw. It will also ‘be assumed that the clamp
the nut in the wheel slide whereby rotation of the feed
screw will effect feeding movement of the slide.
Secured to the right hand end of the base 12 is a sub
4 thereby turning the gear 115 clockwise, the pawl 118 60 frame 142 (FIG. 6) which supports the compensating
will turn the ratchet wheel 1'17 and the lead screw 36
in a similar direction. When the piston 95 returns to
the right, thereby driving the gear 115 in a counterclock
wise direction, the pawl 118 will ratchet over the teeth
of the wheel 117 and the feed screw 36 will remain sta 65
tionary. Depending on the setting of the selector knob
104», the ratchet wheel will be advanced through a dis
tance of l, 2, 3, or 4 teeth thereof and cause correspond
feed mechanism hereinafter to be described. The right
hand end of the feed screw 135 extends into the subframe
where it is ?tted with a spur gear 143.
This gear is se
curely fastened to the end of the feed screw and is pro
vided with a hub ‘144 having ?nished end face 145. This
face is adapted to abut against a ?nished surface 141 pro
vided on the right hand end of the base 12. The gear
143 meshes with a pinion 1146 formed on a shaft 147
which is journaled for rotation in the subframe by anti
ing amounts of diamond advance.
To permit manual operation of the feed screw 36 in 70 friction bearings 148 and 149. Secured to the shaft 147
either direction by a handwheel (not shown), an Auto
Manual selector knob 123 is provided on the side of the
housing 98. This knob is adapted to rotate a hub 124
by a pin 150 is a ?ne ratchet wheel \151 provided with a
large number of ratchet teeth 152 (see also FIG. 9). Co
operating with the ratchet teeth 152 are pawls 153
154 (FIG. 6) which are pivoted on a screw 155
.
carrying an eccentrically mounted lug 125 ‘which lies be~
neath the right hand end of the pawl 118. Hence, when 75 9) carried by an arm 156. The arm 156 is journaléibh the
3,060,647
7
8
shaft 147 by antifriction bearings 157 and is provided with
The hydraulic control circuits for the plungers 190 and
a lateral extension 158 which supports a pair of compres
sion springs 159 acting on the free ends of pawls 153 and
154. The pawls are thereby resiliently urged toward the
191 are shown in FIG. 7 of the drawings. In this circuit
the pressure and exhaust lines 40 and 44 are understood
to be connected to the corresponding lines shown in
periphery of the ratchet wheel 151 so as to maintain an
FIG. 5. Operation of the plunger 190 for the ?ne ratchet
advancing tooth 1160 on each of the pawls in engagement
with the ratchet teeth 152. A pair of retaining pawls 161
wheel 151 is controlled by a solenoid valve 214 while
operation of the plunger 191 for the coarse ratchet wheel
pivoted on a bracket 162 extending from the frame 142
168 is controlled by a solenoid valve 215. The valves are
are urged by compression springs 163 into engagement
?tted with spools 216 and 217, respectively, which are
with the teeth of ratchet wheel 151 to resiliently hold the 10 urged toward the left by compression springs 218 and
ratchet wheel in the position to which it is moved by the
219. When the spool 216 is in the position shown in
pawls 153 and 154 and to prevent retrograde movement
FIG. 7, ?uid under pressure is delivered from line 40
of the wheel.
to a line 220 while the exhaust line 44 is connected to a
Secured to the right hand end of shaft 147 (FIG. 6)
line 221. Hence, fluid under pressure is delivered to the
by a key and a retaining nut 167 is a coarse ratchet wheel
space between the left hand end of plunger 190 and the
168. As shown in FIG. 8 this wheel is provided with
adjustable plug 196 so as to maintain the plunger in its
ratchet teeth 169 which are considerably fewer in num~
right hand position. When the solenoid ISOL is ener
her than the teeth on the ?ne ratchet wheel previously
gized, the spool 216 will be moved to the right against
described. The teeth 169 are adapted to be engaged by
the urgency of spring 218 thereby causing ?uid under
an inserted tooth 170 provided in a pawl 1'71 pivoted on a 20 pressure to be applied to the line 221 and line 220 to be
screw 172 carried by an arm 173. As shown in FIG. 6,
connected to exhaust. Hence, the plunger 190 will be
the arm 173 is journaled for rotation on the shaft 147 by
moved to the left to the extent permitted by the setting
antifriction bearings 174 and is provided with a lateral
extension 175 supporting a compression spring 176 which
presses against the free end of pawl 171 and resiliently
urges the tooth 170 into engagement with the teeth 169.
Also cooperating with the teeth 169 of the coarse ratchet
of the stem 202 and the ratchet wheel 151 will be ad
vanced by the pawls 153, 154. When solenoid ISOL is
dienergized, the spool 216 will be returned to the position
shown in FIG. 7 by spring 218 and the plunger 190 will
be returned to its initial position thereby returning the
wheel 168 is a sensing pawl 179 pivoted on a screw 13%.
feed pawls to their starting positions.
The pawl is provided with an inserted tooth 181 which
In a similar manner, when the coarse solenoid 2SOL is
is urged into contact with the teeth 169 by a compression 30 energized, the spool 217 will be ‘moved toward the right
spring 182. On the opposite side of its pivot, the pawl
against the urgency of the spring 219 and cause ?uid
is provided with an adjustment screw 183 which is adapted
under pressure to be applied to a cylinder line 224 while
to cooperate with the operating plunger of a limit switch
a line 225 will be connected to the exhaust line 44. Hence,
4L5 carried by a bracket ‘184 secured to the frame 142.
the plunger 191 will be moved toward the left against
The ratio of the lever arms of the pawl 179 is such that
the urgency of the compression spring 193 to the extent
a small movement imparted to the pawl by the inclined
permitted by the setting of the stern 207. The pawl arm
surface of a tooth 169 is ampli?ed into a much larger
173 will thereby be rotated clockwise and cause the coarse
movement of the screw 183. The screw 18?: is adjusted
ratchet wheel 168 to be given a step of advancing move
until it just operates the limit switch 4LS with the tooth
ment by the pawl 171. When the solenoid 2SOL is de
181 located in the bottom of a tooth space as shown in 40 energized, the spool 217 will be returned to the position
FIG. 8. The setting should be such that even a slight
shown in FIG. 7 as will also the plunger 191 and the feed
movement of the tooth 181 up the inclined face of a
pawl 171. In order to prevent overthrow of the coarse
tooth 169 will release the limit switch.
ratchet wheel 168 on the advancing stroke, a check valve
The pawl arms 156 and 173 are provided with down
226 and resistance 227 are inserted in parallel in the
wardly projecting teeth 136 (FIG. 2) and 187 (FIG. 9),
line 225 as shown. Hence, when pressure is applied to
respectively, which engage in notches 188' and 189 formed
the right hand end of the plunger 191, ?uid exhausting
in a ?ne plunger 190 and a coarse plunger 191.
The
plunger 190 (FIG. 2) operates in a cylinder 192 formed
in the frame 142. Likewise, the plunger 191 operates
in a cylinder 193 also formed in the frame 142.
The
plunger 190 is urged toward the right against a sealing
plug 194 by a compression spring 195 which is com
pressed between the plunger and adjustable sealing plug
196. In a similar manner, the plunger 191 (FIG. 9) is
urged toward the right‘ against the end of a sealing plug
197 by a compression spring 198 which is compressed
between the plunger and an adjustable sealing plug 199.
As shown in FIG. 2, left hand movement of the plug 196
is prevented by a stern 202 of a setting knob 204. The
stem 202 is slidable within a bushing 203 secured to the
frame 142 and carries a radially extending pin 205 which
is adapted to engage in any one of four notches pro
vided on the end of a sleeve 206 ?tted in the bushing 203.
These notches are of different depth so as to permit vary
ing degrees of movement of the plunger 190 to the left
against the urgency of its spring 195.
Similarly, left hand movement of the adjustable plug
199 is limited by the stem 207 of a setting knob 209. The
from the left hand side of the plunger through line 225
will be prevented from passing through the check valve
226 and forced to ?ow through the resistance 227 on its
way to the exhaust line 44. This will slow the movement
of the plunger and prevent overthrow. When the sole
noid ZSOL is deenergized, pressure from line 40 will be
applied to the line 225 and will be permitted to ?ow un
impeded through the check valve 226 on the return stroke
of the pawl 171.
To facilitate setting of the stems 202 and 207, a pres
sure release button 230 is provided. This button is con
nected to the spool 231 of a valve 232 to which the pres
sure and exhaust lines 40 and 44 are connected as shown.
The spool 231 is normally urged toward the left by a
compression spring 233 so that the spool prevents ?uid
under pressure in the line 40 from ?owing out through
the exhaust line 44. However, when the button 230 is
held depressed against the urgency of spring 233, the
line 40 will be communicatively connected with the line
44 thereby dropping the pressure in the system to a point
where the knobs 204 and 209‘ may easily be pressed in
wardly against the urgency of springs 195 and 198 and
stem 207 is slidably received in a bushing 208 secured to
rotated to the position desired.
the frame 142 and carries a radially extending pin 210 70
The mode of operation of the mechanism thus far
which is adapted to cooperate with any one of four cir
described is as follows: Fine compensation for wheel wear
cumferentially spaced notches in the end of a sleeve 211
occurring during the grinding process is effected by ad
?tted in the bushing 208. These notches are of varying
vancement of the ?ne ratchet wheel 151 under the con
depth to permit different‘ degrees of movement of the
trol of the solenoid operated valve 214. As the grind—
plunger-“191 to the left.
ing wheel wears and the parts being ground tend to be
3,060,647
9
come oversize, the solenoid 1801. is energized by the
operator to give the pawl arm 156 a feeding movement
thereby advancing the ratchet wheel 151 and the feed
screw 135 of the grinding machine infeed mechanism.
When the knob 204 (FIG. 7) is adjusted for the smallest
possible increment of wheel wear compensation, the stroke
permitted the plunger 1% is such as to move the pawl
tooth 160 through a distance equal to one-half of a
tooth space. For this purpose the pawls 153 and 154
10
access to the end of the shaft 147. By then removing the
nut 167, the ratchet wheel 168 may be removed and
another wheel inserted in its place. With the substitution
of a new coarse ratchet wheel 168 on the shaft 147,
the stroke adjustment knob 204 for the ?ne plunger 190
(FIG. 2) may be set to provide for the appropriate size
stroke of the arm 156 to effect an advance of the coarse
ratchet wheel through one tooth space for each ten os
cillations of the ?ne pawl arm. For example, the strokes
(FIG. 6) are offset from one another by a distance equal 10 of this arm may include, in addition to the stroke equal
to one-half of a tooth space as previously mentioned,
to one half of a tooth space so that on successive strokes
strokes equivalent to one, one and a half and two tooth
of advancing movement of the pawl arm 156, alternate
spaces.
pawls will be operative to advance the ratchet wheel
Referring now to the electrical control circuits for the
through a distance equal to one half of a tooth space.
The retaining pawls 161 are also offset from one another 15 ‘automatic truing and phase out mechanisms as shown in
by a distance equal to one-half of a tooth space so that one
of these pawls will always drop behind a ratchet tooth
upon a half-step advance of the ratchet wheel.
In the case of the coarse ratchet wheel 168 which is
secured to the shaft 147 and moves as a unit with the
?ne ratchet wheel 151, this wheel may, for example, be
provided with only one ?fth as many ratchet teeth as the
wheel 151. Hence, ten oscillations of the ?ne ratchet
the wiring diagram (FIGS. 10a and 10b), energy for the
circuits is provided from a source 236 which is connected
to a pair of conductors 237 and 238 across which the
various energizing circuits are connected.
A series of
reference numbers is provided along the left hand margin
of the wiring diagram to indicate the lines of the diagram
on which the various contacts and components appear.
In the right hand margin of the diagram are provided
legends for indicating the functions performed by the
arm 156 will be required to advance the coarse ratchet
wheel 168 through a distance of one tooth space. The 25 solenoids, relays, etc. The. numbers following the leg
ends refer to the lines of the diagram in which the relay
Wheel slide compensation effected by a movement of the
contacts are found, the underscored numbers designating
coarse ratchet wheel through a distance of one tooth space
normally closed contacts.
To condition the grinding machine for operation a
under the control of solenoid 6SOL. It will thus be ap 30 Master Start pushbutton 2P3 (line 11) is depressed there
by energizing the relay 2M which starts the hydraulic
preciated that for each advance of the ?ne ratchet wheel
pump motor to provide operating pressure for the hydrau
through a distance of one half tooth space, the coarse
lic circuits. When the relay 2M is energized, its contacts
ratchet wheel will be advanced through a distance equal
is desirably made equal to the advance of the truing dia
mond each time the plunger 95 (FIG. 4) is reciprocated
to one tenth of a tooth space.
Hence, if after a wheel
in line 12 are closed around the pushbutton switch 2PB
truing cycle has been effected, a total of, for example, 35 thereby maintaining the relay energized after the push
button is released. The relay may be deenergized to
four ?ne compensations are entered under the control
stop the motor by depressing the Master Stop pushbutton
of solenoid ISOL, then the tooth 170 of the coarse feed
lPB which breaks the circuit through the relay and stops
pawl 171 will have moved four tenths of the way up the
the motor. Although not shown in the present wiring
inclined face of a tooth 169 as illustrated in FIG. 11.
diagram, corresponding starting circuits may be provided
If, now, a truing operation is initiated, the diamond will,
for the other prime movers of the grinding machine.
due to the amount of wheel wear occurring during the
To start an automatic truing cycle, the Truing Start
grinding operation, remove only six tenths of the normal
pushbutton SPB in line 15 is depressed thereby energiz
amount of material from the surface of the grinding wheel
ing a clutch coil 240 of the counter 25 (FIG. 1). The
since no provision is made for incrementally advancing
the diamond to compensate for wheel wear. Hence, in 45 clutch coil is maintained energized by the cont-acts 7CR
(line 16) of a relay 7CR (line 28) which is energized by
order to maintain the wheel slide in phase with the dia
closure of contacts COB-1. The contacts COB—1 are
mond, it is desirable that the wheel slide be advanced
provided in the counter 25 and remain closed so long as
only to an extent corresponding to the amount of ma
the clutch coil 240 is energized.
terial which will be removed by the diamond on its ?rst
As heretofore indicated, the counter 25 controls the
pass across the wheel. Hence, if a coarse compensation 50
number of passes of the truing tool across the face of
of the wheel slide is now entered by energization of sole~
the grinding wheel. The counter per se forms no part
noid 2SOL, the coarse pawl arm 173 will be oscillated
of the present invention and may comprise a known type
but the coarse ratchet wheel 168 will be advanced through
of unit which is capable of being preset to count 3. pre
a distance of only six-tenths of a tooth space. This re
sults from the fact that four-tenths of the movement of 55 determined number of electrical impulses and provide a
. suitable signal when the count is completed. One form
the pawl tooth 170‘ will be lost motion. In other words,
of counter which is suitable for the present purpose and
the pawl will move idly until it engages the tooth and
which is commercially available is the reset type of counter
advances it through the ?nal six-tenths of the stroke of
the pawl.
manufactured by the Eagle Signal Corp. and known as
enable the advance of the coarse ratchet wheel 168 to cor
the mechanism of the counter will be advanced one step
Since the wheel truing mechanism of the present ma 60 Model No. HZ50A6. When the clutch coil of this count
er is energized, the device is conditioned for counting and
chine is provided with four degrees of diamond advance,
each time a count coil 241 is energized and deenergized,
as controlled by the knob 104 (FIG. 4), it is desirable to
respond therewith. As previously described, the ad
until the desired count has ‘been effected. Thereupon
the wheels is provided with a tooth spacing correspond
ing to one of the four strokes of movement given to the
pawl 171 by its arm 173. To permit interchange of the
closed and relay 6CR will be energized upon closure of
contacts 7CR in line 27. Hence, the normally open con
tacts 6CR in line 14 will be closed and the count coil 241
coarse ratchet wheels, the frame 142 is provided with a
will be energized so as to condition the counter to count
cover 235 (FIG. 6) which may be removed to provide
the ?rst pass of the truing tool across the grinding wheel.
vance of the plunger 191 may be adjusted to four dif 65 the contacts COB—-1 will open thereby deenergizing re
lay 7CR and dropping out the clutch coil 240 to ter
ferent degrees of movement by appropriate setting of the
minate the counting operation and reset the counter.
knob 209. Each adjustment of the knob 209 is there
Assuming that the carriage 32 is in its home position
fore made to correspond with one of the adjustments of the
with the limit switch 3L8 held operated ‘by dog 64 (FIG.
diamond advance knob 104 and a set of four coarse ratch
et wheels 168 is provided with each machine. Each of 70 3), the contacts 3LS (FIG. 10a) in line 27 will be held
3,060,647
13
1
‘
total amount of ?ne compensation entered by pushbutton
10PB during the grinding operation. As previously ex
plained, this will bring the wheel slide into phase with the
truing tool Since the advance of the slide will be equal
to the material removed from the wheel on the ?rst pass
of the tool. In this connection it will be recalled that
the amount of material removed from the wheel on the
?rst truing pass is equal the total advance of the truing
14
may be resorted to without departing from the boundaries
of the invention as de?ned by the claims which follow.
What is claimed is:
.
l. A device for bringing a wheel slide of a grinding
machine into phase with a tool rfor truing a grinding
wheel thereof after one or more ?ne incremental move
ments of the wheel slide independently of the truing tool
comprising, selectively operable means to give the wheel
slide a ?ne increment of advancing movement to com
10 pensate for wear of the grinding wheel during grinding
operations, means to traverse the truing tool across the
After the advance of the coarse ratchet Wheel by pawl
tool minus the amount of ?ne compensation of the wheel
slide during the grinding operation.
171, the limit switch 4LS will be operated by pawl 179
(FIG. 8) dropping into the bottom of the next tooth
grinding wheel, means to give the truing tool an incre
ment of movement towards the grinding wheel on each
traverse of the tool across the wheel, actuating means to
space. Hence, the contacts 4LS in line 41 will close and,
since contacts ISCR in this line are now closed, the relays 15 give the wheel slide a coarse increment of advancing
movement each time the truing tool is advanced toward
3TR and 4TR will be energized. The contacts 3TR in
the grinding wheel, said coarse increment of movement
line 33 will be closed but this is of no consequence since
being equal to the incremental advance of the truing
the delay contacts 2TR in line 34 are still closed. The
tool, and means to mechanically sense the amount of
contacts 4TR in line 37 will open and deenergize relay
13CR thereby permitting the pawl 171 to return to its 20 incremental movement given to the wheel slide by said
selectively operable means and to reduce the coarse
initial position. Also, the contacts 3TR in line 39 will
increment of movement given to the wheel slide by said
time open and drop out relays ISCR, STR, and 4TR.
actuating means by a corresponding amount to thereby
Thereby, the contacts 3TR in line 33 will open and per
bring the wheel slide into phase with the truing tool.
mit relay IZCR to drop out. The contacts 4TR in line
2. The device of claim 1 wherein said mechanical
37 will time close but this will be without eifect since 25
sensing means includes a lost-motion connection between
relay 120R has now dropped out and opened its con
said actuating means and the wheel slide.
tacts in line 37. Also, the contacts 3TR in line 39 will
3. The device of claim 2 wherein said lost-motion
close and prepare relay 150R for energization on the next
connection is variable in accordance with the amount of
operation of limit switch 4LS.
When the carriage 32 moves out at the reversal posi 30 incremental movement given to the wheel Slide by said
selectively operable means.
tion toward the home position, the timer relay 2TR will
4. A device for bringing a wheel slide of a grinding
again be energized and will again drop out after the car
machine into phase with a tool for truing a grinding
riage returns home. Accordingly, the truing tool will
wheel thereof after one or more ?ne incremental move
again be advanced and the wheel slide will be given an
ments of the wheel slide independently of the truing tool
35
increment of coarse compensation equal to the amount
comprising, selectively operable means to give the wheel
of diamond advance at the home position. The result
slide a ?ne increment of advancing movement to com
ing operation of limit switch 4LS will cause energization
pensate for wear of the grinding wheel during grinding
of relays 15CR, 3TR and 4TR in the same manner as
operations, automatic means for truing the grinding
described above.
With the present mechanism there is a possibility, if 40 wheel including means to traverse the truing tool back
and forth across the face of the grinding wheel and
the operator is not otherwise instructed, that the number
means to impart to the truing tool an increment of
of ?ne compensations entered by the pushbutton 10PB
movement toward the grinding wheel on each pass of
may exceed the number of steps of the ?ne ratchet wheel
the tool thereacross, actuating means to give the wheel
per tooth of the coarse ratchet wheel. In this case,
when the sensing pawl 179 drops into the bottom of a 45 slide a coarse increment of advancing movement each
time the truing tool is advanced toward the grinding
tooth space on the coarse ratchet wheel, the timer relay
wheel, said coarse increment of movement being equal
3TR will be energized and close its contacts in line 33.
to the incremental advance of the truing tool, and means
Diamond advance relay 12CR will thereby be energized
effective on the ?rst pass of the truing tool across the
and cause advance of the truing tool toward the grind
face of the grinding wheel to mechanically sense the
ing wheel. Since the amount of material worn from the
wheel is equal to one coarse compensation which is
50 total amount of incremental movement given to the
equal to the amount of diamond advance, the diamond
will again be in position to take a full cut when trav
reduce the coarse increment of movement given to the
wheel slide by said selectively operable means and to
wheel slide by said actuating means by a corresponding
Energization of relay 12CR will cause its contacts 55 amount to thereby bring the wheel slide into phase with
the truing tool.
12CR in line 37 to close but relay 13CR will not be
5. The device of claim 4 including means to cause
energized since the contacts 4TR (line 37) of timer relay
said imparting means to give the truing tool an incre
4TR are now open. This results from the energization
ment of movement toward the grinding wheel whenever
of this relay simultaneously with relay 3TR. After a
predetermined time delay, contacts 3TR in line 39 will 60 the movement of the wheel slide by said selectively
operable means is equal to a coarse increment of move
open and deenergize relay 15CR. Contacts 15CR in
ment thereof, and means rendered effective by said last
line 41 will open and drop out relays 3TR and 4TR.
named means to prevent the actuating means from giving
Thus, relay 12CR will be deenergized and open its con
the wheel slide a coarse increment of advancing move
tacts in line 37 before the contacts 4TR in this line time
closed. Hence, relay 13CR will not be energized and no 65 ment whereby the wheel slide and truing tool will be
maintained in phase.
coarse compensation of the wheel slide will take place.
6. A device for bringing a Wheel slide of a grinding
Accordingly, the wheel slide and diamond will again be
machine into phase with a tool for truing a grinding
in phase with one another just as they were at the end
ersed across the wheel.
of the previous truing cycle.
wheel thereof after one or more ?ne incremental move
bodiment thereof and certain speci?c terms and language
have accordingly been used herein. It is to be under
slide a ?ne increment of advancing movement to com
In the foregoing description, the invention has been 70 ments of the wheel slide independently of the truing tool
comprising, selectively operable means to give the wheel
described in connection with one possible form or em
pensate for wear of the grinding wheel during grinding
operations, means to impart to the truing tool an incre
stood, however, that the present disclosure is illustrative
rather than restrictive and that changes and modi?cations 75 ment of movement toward the grinding wheel, actuating
3,060,647
15
means to give the wheel slide a coarse increment of ad
vancing movement each time the truing tool is advanced
toward the grinding wheel, said coarse increment of
movement being equal to the incremental advance of the
truing tool, means to cause said imparting means to give
the truing tool an increment of movement toward the
16
of advancing movement whereby, upon operation of said
coarse feed pawl, the wheel slide will be advanced a dis~
tance corresponding to the distance represented by one
tooth space on said coarse ratchet wheel minus the number
of ?ne increments of movement given the wheel slide by
said selectively operable means subsequent to the next
grinding wheel Whenever movement of the wheel slide
due to repeated operation of said selectively operable
preceding operation of said coarse feed pawl.
means is equal to a coarse increment of movement
to the truing tool during wheel truing operations an in
crement of movement toward the grinding wheel equal to
the distance moved by the wheel slide when the coarse
thereof, and means rendered effective by said last-men
tioned means to prevent said actuating means ‘from giv
ing the wheel slide a coarse increment of advancing
movement whereby the wheel slide and truing tool will
be maintained in phase.
8. The device of claim 7 including means to impart
ratchet wheel is moved through a distance of one tooth
space, and means rendered effective by said imparting
means to cause said actuating means to give said coarse
7. A device for bringing a wheel slide of a grinding 15 feed pawl a stroke of movement on each advance of the
truing tool.
machine into phase with a tool for truing a grinding
wheel thereof after one or more ?ne incremental move
9. The device of claim 8 including means to cause
ments of the wheel slide independently of the truing
said imparting means to give the truing tool an increment
of movement toward the grinding wheel whenever the
tool comprising, a ?ne ratchet Wheel, a coarse ratchet
movement of the wheel slide by said selectively operable
wheel connected to said ?ne ratchet Wheel for rotation
in synchronism therewith, the number of teeth on the
?ne ratchet wheel being equal to the number of teeth
on the coarse ratchet wheel multiplied by a Whole num
ber, feed means for advancing or retracting the wheel
slide, means operatively connecting said ratchet wheels to
said feed means, a feed pawl cooperating with said ?ne
ratchet wheel, selectively operable means to oscillate
said pawl through a ?xed stroke to give the wheel slide
a ?ne increment of advancing movement, a coarse feed
pawl cooperating with said coarse ratchet wheel, and 30
actuating means to oscillate said coarse feed pawl through
a ?xed stroke equal to one tooth space of said coarse
ratchet Wheel to give the wheel slide a coarse increment
means is equal to a coarse increment of movement
thereof, and means rendered effective by last said-men
tioned means to prevent the actuating means from giv
ing the wheel slide a coarse increment of advancing
movement whereby the wheel slide and truing tool will
be maintained in phase.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,709,877
Dall et al. ____________ .. June 7, 1955
2,718,101
2,882,649
Stuckey et al __________ _._ Sept. 20, 1955
Grove ______________ __ Apr. 21, 1959
2,937,639
Grove _______________ __ May 24, 1960
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