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Патент USA US3053413

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Sept. Il, 1962
FileaJune 24. 1959
'7 Sheets-Sheet 1
A rroAwe-rs
Sept. 1l, 1962
Filed June 24, 1959
'7 Sheets-Sheet 2
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SePt- 11, 1962>
Filed June 24, 1959
'7 Sheets-Sheet 3
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Sept'. 1‘1', T962?
Filed June 24', 1959
7 Sheets-Sheet 4
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Sept. l1, 1962
Filed June 24, 1959
7 Sheets-Sheet 5
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By ¿on/Alea A. ron/¿fs
Sept. 1l, 1962
Filed June 24, 1959
7 Sheets-Sheet 6
Sept 11, 1962`
1 3,053,402
United States Patent Oiiìce
Patented Sept. 11, 1962
the stack as the elevator lowers the bottom case to the
conveyor with the cycle repeating until all of the cases
of the stack have been deposited by the elevator on
the «conveyor and discharged from the machine.
Another object of the invention is the lprovi-sion of
an 'article handling machine which is selectively operable
Robert J. Russell, Northl'ield, Mass., Joseph F. Cella,
Brouxville, N.Y., and Edward A. Towles, Northamp
ton, Mass., assignors to Cella Machinery Inc., New
York, N.Y., a corporation of New York
to stack cases at one time and unstack cases at another
Filed .lune 24, 1959, Ser. No. 822,602
4 Claims. (Cl. 214-6)
time, with whichever operation desired beingsele'cted by
the machine attendant. While hereinafter the :invention
This invention relates to machines for stacking and/ or 10 is described `and claimed in connection with case stack
ing and un-stacking, it should be understood that the word
unstacking articles such as boxes, milk cases, or the like.
case is used broadly to describe boxes, crates, and the
The invention as disclosed herein is adapted to receive
successive articles to be stacked from a line of such arti
Other objects, advantages, and meritorious features
cles moving along on a conveyor, Istack the articles, and
will more fully appear from the specification, claims,
discharge the stack from the machine. In the alternative,
and accompanying drawings wherein: A g
a machine embodying the invention as disclosed herein
FIG. 1 is a top view of a mach-ine embodying the
is adapted to receive successive stacks of articles from a
line -of such stacks moving on a conveyor and unstack
FIG. 2 is va cross sectional view taken on' the line 2-2
each stack, discharging the unstacked »articles from the
A primary object of the invention is the provision of
a stacking and/or unstacking machine which is fully auto
matic in oper-ation, is oñ small, compact size in relation
to the operation it performs and the articles it handles,
of FIG. l;
behind the other on a conveyor which runs through the 30
control `system ofthe machine, FIG. 7 relating primarily
to that ‘portion of the system which is operative when
FIG. 3 is a cross sectional view taken on the line
3_3 of FIG. 2;
FIG. 4 is a cross sectional view taken on the line 4-4
of FIG. 3;
FIG. 5 is a schematic view showing the relative posi
which may be fabricated at a low cost, and installed with 25
tions between cases during the stacking operation;
a minimum of disturbance of the article conveyors with
FIG. 6 is -a schematic view showing the relative posi
which it is to be associated.
tions of cases during an unstacking operation;
Another object of the invention is the provision of a
FIGS. 7 and 8 are schematic views of the electrical
machine which will stack boxes or cases moving one
machine by picking successive cases upwardly off the
conveyor to place each case so removed beneath a case
case stacking is selected, and FIG. 8 relating to that por
previously removed until a stack of `determined height
tion of the system which is operative when unstacking is
has been accumulated, and thereafter place the stack
back on the conveyor from which the cases were originally
The machine described herein is particularly well suit
ed for the stacking or unstacking of milk bottle cases and
drawn so that the stack may be discharged from the
when used as a stacker in a dairy, is positioned over a
Another object of the invention is the provision of
an unstacking machine adapted to receive successive stacks
case conveyor carrying ñlled cases away from the
machine which deposits the milk bottles in the cases. In
Iol‘î boxes or cases from la conveyor running through the 40 the event the machine is to be used as an unstacker, it is
positioned over the case conveyor somewhere ahead of
the station at which the empty bottles are removed from
most case of the stack land place it on the same conveyor
the cases, or in the event of the cases being used for
by which the stack entered the machine so that the case
packing paper cartons of milk and where the cases are
may be discharged from the machine, and automatically
repeat the operation until -all of the cases of successive 45 returned empty to the dairy, the machine would be posi
machine and which will successively remove the lower
stacks have been discharged from the machine.
Another object of the invention is the provision of a
tioned ahead of the case washing machine. Where the
machine is to be used in a dual capacity, i.e., at one time
case »stacking machine which includes »a reciprocating
case elevator operable to raise successive cases olf of
as a stacker and at :another time as an unstacker, the
a case conveyor and place them on cooperating case sup
conveyor system with which it is associated will have a
50 single conveyor common to the machine which is capable
of operation in opposite directions and during operation
porting means which supports each case spaced above
the conveyor a distance exceeding the height of the foil
in one direction will deliver stacks of cases to the machine
lowing case, with `the means for supporting the cases above
for unstacking, and when operated in the other direction
will deliver single cases` to the machine for stacking.
The machine disclosed herein stacks and unstacks
cases so supported on the folowing case as the same is 55
cases from the bottom. In other words, rather than plac
raised by the elevator, and with such supporting means
ing successive cases one on top of the other as would
being extensible to support the last raised case and those
resting thereupon to all-ow the elevator to return to a
normally »be done by hand in building a stack, this
the conveyor being automatically retracted to place the
lowered position preparatory to raising the next following
Another object of the invention is the provision of
a case unstacking machine which includes ‘an elevator for
raising `a stack of cases oiï of a case conveyor with a
case holding `device operable -synchronously with the ele
machine places successive cases one beneath the other
60 to Ibuild the stack. In unstacking, the machine with
draws successi-ve cases from the bottom of a stack rather
than withdrawing the cases from the top of the Stack.
The unstacking operation is essentially merely the reverse
of the stacking operation with certain variations,
vator to support the stack of cases above the lowermost 65
The machine as disclosed herein has been designed for
case and hold ysuch stack elevated as lthe elevator moves
use with what is termed an “in-floor” conveyor, which
downwardly to place the lowermost case lon the conveyor,
type of conveyor is coming into widespread use in the
dairy industry. The machine is simply placed in the door
through which the in-floor conveyor travels with provi
previously unstacked case- has been discharged from the 70 sion being made to allow the case lifting fingers of the
machine to allow the elevator to lower the stack the
case elevator to drop below the case supporting surf-ace
height of the bottom case and thereafter again support
of the conveyor.
and which stack holding device will release the stack when
the elevator returns upwardly from the conveyor after a
A typical installation for handling conventional milk
bottle cases of a size approximately 14" long by 111/2"
wide, would occupy a space roughly 3'4” square centered
are again extended, the elevator reverses its travel, and
during descent places the case on the supports and con
tinues back down to its starting position to repeat the
over the case conveyor and with the height of the machine
being substantially equal the height of the stack of cases
to be handled. The machine, generally indicated at 20,
The elevator comprises a pair of identical mechanisms
on opposite sides of the conveyor 22 and disposed between
the uprights of the frame. Each such mechanism includes
»a pair of vertical rods 96 and 98 for one mechanism, and
100 and 102 for the other. Hereafter a description of
is adapted to rest on the floor over which the cases are
conveyed by the case conveyor 22. The case conveyor
serves to deliver cases to and discharge cases from the
machine, and is a conventional double chain conveyor. 10 one such mechanism will sullice for both. The rods are
mounted on the upright frame members in blocks 99
The cases rest on the chains and as the chains move, the
and 101 secured to the frame members and to opposite ends
cases are frictionally carried therewith. The machine has
of the rods. &lpported for vertically slidable movement
a frame comprising, as best shown in FIGS. l and 2,
on the rods is an elevator carriage which includes a pair of
four upright channel members 24, 26, 28, `and 30, which
are secured by angle plates 32, 34, 36, and 38 to a pair
of lloor plates 40 and 42 disposed on opposite sides of
vertical members 104 and 106 having rod bearings 108,
110, 112, and 114 secured thereto and received upon the
rods, with a horizontal cross member 116 extending be
tween and secured to the upper ends of members 104 and
106. Secured to the lower end of the carriage and specili
like 44. Disposed at opposite sides of the conveyor 22
and carried by this frame is the vertically shiftable case 20 cally to the lower ends of members 104 and 106 are the
elevating and lowering mechanism indicated generally at
elevator lingers 118 and 120 which, as will be noted with
respect to linger 118 in FIG. 3, extend beneath the path of
46, as well as the case retaining mechanism which includes
travel of a case on conveyor 22.
the supporting mechanism 48 and the case holding or
The elevator lingers are raised and lowered by a fluid
clamping mechanism ‘50, the latter being operative only
during unstacking.
25 pressure cylinder 122 which acts upon the elevator car
riage. Cylinder 122 is secured at the lower end to the
Tie plates 52 are secured to uprights 24 and 26 as
lloor plate 42, and at the upper end has a piston rod 124
shown in FIGS. 1 and 2, and a similar tie plate, not
connected to the cross piece 116 of the carriage. Upon
shown, rigidilies uprights 28 and 30. Another tie plate 54
the case conveyor 22. The lloor plates may in turn be
secured to the floor of the building as by bolts or the
pressurization of the cylinder at the lower end the lingers
extends across conveyor 22 spaced thereabove so as not
to interfere with case travel on the conveyor and is 30 are raised, While pressurization at the opposite end causes
secured between and to the upper ends of uprights 26
and 30 to tie the upper ends of the framework on op
posite sides of the conveyor together.
Assuming the machine is to be used for stacking cases,
the lingers to be lowered. The complemental elevator
fingers 118a and 120a on the opposite side of the case con
veyor cooperate with lingers 118 and 120 to raise cases
off the conveyor or replace elevated cases on the conveyor.
The lingers come up simultaneously beneath the bottom
of the cases to raise them from the conveyor.
the direction of arrow S in FIG. 1, one behind the other.
The case supports 48, which hold the previously raised
As the leading case passes between uprights 26 and 30
and its leading edge is about one-half the way through
cases elevated as succeeding cases are brought up to be
stacked beneath those held by the supports, comprise the
the machine, it strikes the arm 56 of switch LS-l, which
in turn activates lluid pressure cylinder 58 to withhold 40 aforementioned four lingers 86, 86,1, 88, and 88a, which
the advance of those cases following the leading case.
are mounted for extensible and retractible movement with
two of the fingers disposed on each side of the conveyor
Cylinder 58 is pivotally connected at 60 to a bracket 62
22 and yat a height thereabove so that they will clear the
secured to upright 30 and at the opposite end has a pis
top of the highest case which may be stacked or unstacked
ton rod pivotally connected at 64 to a case stop 66, in
turn pivotally supported by a bracket 68 secured to up 45 by the machine. A description of one pair of lingers as
shown in FIGS. 3 and 4 will suffice for both pairs. The
right 30. As LS-l is tripped, it causes pressurization of
fingers are carried by sleeve bearings 126 and 128 slid
cylinder 58 to pivot the stop 66 from the solid to the
ably mounted on rods 130 and 132, which are carried at
phantom outline position in which the stop presses against
opposite ends by vertical plates 134 and 136 upstanding
the case next following the leading case and withholds
its movement.
50 from and secured to the iloor plate 42. A cross member
138 extends between and is secured to the lingers behind
The leading case continues to travel until it comes into
the sleeve bearings to prevent revolution of the lingers
abutment with the extended case locators 74 and 76. The
on the rods. The fingers are disposed just beyond the
case locators are a pair of abutments or stops, one at
edges of vertical plate 134 and reciprocate from a re
each side of the path of case travel, which are extensibly
tracted position shown on both sides of conveyor 22 at
and retractibly carried by bearings 78 and 80 secured to
86 and 86„ in FIG. 6 and an extended case supporting
uprights 28 and 32, and are actuated for such movement
position shown at 86 and 86„ in FIG. 5. A lluid pressure
by fluid pressure cylinders 82 and 84, also mounted in
cylinder 139 suitably supported Áat one end on an angle
any convenient fashion on uprights 28 and 32. As will
member 141, secured to vertical plate 136, and having a
`hereafter appear, these locators remain in the extended
position during the stacking operation and retract to let a 60 piston rod 140 connected to cross member 138, is opera«
tive to extend and retract the pair of lingers 86 and 88,
stack pass out of the machine on conveyor 22 at the end
while a similar cylinder is operative to accomplish the
of the stacking operation.
same with the other pair of lingers 88 and 88a.
When the case actuates switch LS-l, such switch ini
Considering FIGS. 3 and 5, the sequence of operations
` tiates a time delay relay 'fR-1, which relay measures a
determined interval of time suñ‘icient to allow the case 65 in stacking cases may be readily comprehended. Assum
ing a case C-2 is supported by the supporting lingers, of
to reach the locators 74 and 76 and then causes the case
v which two are shown in FIG, S at 86 and 86a, and another
elevator 46 to start its rising oper-ation to lift the case off
the cases C enter the machine on the case conveyor 22 in
the conveyor to a height above that of the following cases.
The case elevator includes four case lifting lingers indi
cated at 118, 118„ 120, and 120,1, and hereinafter more
fully described. As the case rises, case supports 86, 86a,
case rests on the case conveyor 22 and is in abutment
with the locators 74 and 76, which are in the extended
position shown in phantom outline, as mentioned here
before the case has actuated LS-l and after a short time
delay the elevator starts its upward movement raising the
elevator lingers, of which two are shown at 120 and 120,...
thereon to be placed on the ascending case and to allow
The lingers pick case C~1 off the conveyor and raise it
the ascending case to pass by the supports. When the
ascending case reaches a position above the supports, they 75 toward the position occupied by case C-2. lust before
88, and 88a above it retract, allowing any cases supported
the upper edge of case C-l strikes the Icase supports 86
yand 86a, switch LS-3, mounted on the upright frame
«member 30, is actuated by an adjustable trip 142 mounted
on the elevator member 104. Actuation of switch LS-3
causes the case supports 86 and 86a to be retracted to the
position shown `in FIG. 6. Because case C-1 is moving
rapidly upwardly and the supports are withdrawn from
beneath case C-2 when only substantially one-half inch
turn valves. The solenoids for the operation of such valves
are shown in FIGS. 7 and 8 as at 164 for the' solenoid
that controls the valve which, in turn, controls“ the exten
sion and retraction ofthe case locators 74 and 76. Each
solenoid operated valve, uponv energization of its' respec
tive solenoid, serves to admit fluid pressure to' the as
sociated cylinder to cause extension of the piston rody of
the cylinder, and upon de-energization of the s'olen‘oidthe
valve is spring-returned to a position redirecting lñuid
only slightly, perhaps one-quarter inch, before it seats l0 pressure to thev associated cylinder to cause retraction of
upon case `C-1. With case C-2 now stacked on case
the piston rod associated therewith'. The circuits shown
\C--1, both cases are elevated through the remainder of
in =FIGS. 7 and 8 include the limits »switches _LS-1, LSV-4,
the stroke of cylinder 122. At the top `of the stroke of
etc., hereinabove mentioned. LS-1, shown' in FIG. 7, is
or less exists between the two cases, case `C-2 will `drop
cylinder` 122, and assuming a full stack has not been
accumulated», switch LS-4 is contacted by an adjustable
trip 144 mounted on the elevator carriage and this reversely
pressurizes the cylinders 139 to extend the case supports
86, 86a, 88 »and 88a. When the case supports yare extend
ed, switch LS-7, mounted on the bracket 141 and having
provided with two throw arms, one being indicatedÍ at
LS-la and the other at LS-lb. LS--lEL is a norm-ally open
throw which is closed by a case entering the machine and
contacting the arm 56. LS-lb is a normally closed throw
which is opened by a case entering the machine and strik
ing the actuating' arm S6. It will be noted that whether
a switch arm in contact with the cross member 138 w-hen 20 the throws or switches are normally open or' normally
the supports are retracted, is actuated to cause the elevator
to lower cases C-l and C-2 to the supports, upon which
they are placed as the elevator returns to its starting posi
tion shown at 120 and 120,l in FIG. 5.
closed :isv indicated by whether the throw arm' is above
or below the circuit line in which the switch is sche
matically shown as connected. _
Circuits 7 and 8 include a plurality of relays, the sole
As cases C-1 and >@-2 are now carried by the supports, 25 noids for which are enclosed in circles and give “CR”
another case may enter the machine for stacking. As the
designations. The respective slave switches' which are
elevator reaches the bottom 4of its movement, it trips switch
controlled by relay solenoids are also given “CR” desig
LS-S mounted on the ñoor plate 42, which in turn reversely
pressurizes case stop cylinder 58 to retract the stop 66
away from the case it is holding, allowing such case to en
ter the machine and trip switch LS~1 to repeat the above
the particular relay solenoid which controls it. As'there
described cycle.
As the stack of cases increases in height through repeti
tion of the cycles, the machine automatically stops the
stacking after a determined number of cases have been
stacked, and the stack is thereafter sent out of the machine
on conveyor 22.
Secured to the machine -frame are a
pair of case stacking guides 150 and 152, each generally
L-shaped in cross section and which extend beyond the
nations followed by a number identifying the switch with
may be a number of enslaved switches controlled' by a
single relay solenoid, the various switches controlled b_y
`anypar'ticular relay solenoid are identified successively
Vby alphabetical sub-scripts. . The' circuitry »oïf FIG.y 7
also includes‘a time`> delay type of relay indicated at TR-l
which, upon energization for a determined time interval,
will cause its enslaved switch 'PRK-‘1.a -to be closed. Upon
deenergization of TR-l, switch TR-là will open. Certain
of the relay switches, such as CRAGD, `are normally closed,
i.e., are closed when the controlling relay solenoid is de
height to which the cases are to be stacked. Mounted at 40 energized, While relay Switches such #as CR-fl,a are nor
the upper end of one of the guides is switch LS-6, the ac
mally open and tare closed only when the relay Vsole'noids
tuating arm 154 of which is contacted by the top case of
actuating such switches are energized. Ay further de
the sta-ck as the elevator is raising the entire stack to
scription of the circuit of FIG. 7 is believed unnecessary
place it on the case supports. Upon actuation of LS-6,
as the operation of the machine can be traced through the
cylinder 122 is reversely pressurized and instead of con 45 circuit.
tinuing to raise the stack, the elevator returns it to con
The structure of the machine thus far described is suf
veyor 22 to be carried thereby out of the machine. LS-6
ficient to stack cases entering the indexing station and
also serves to reversely pressurize cylinders 82 and 84 of
release successive stacks from the station for discharge
the case locators, causing retraction of the locators out of
therefrom on the case conveyor 22. With certain addi
the path of the stack so that the stack may leave the ma 50 tions to the structure described, the machine may be made
chine. As the stack leaves the machine and clears the lo
to unstack cases. Reference has heretofore been made
cators 74 and 76, it trips switch LS-S, which causes pres
to the unstackirig circuit (FIG. 8) which would be op
surization of cylinders 82 and 34 to extend the locators
erative during unstacking. With the exception of LS-3,
and reversely pressurize cylinder 58 to allow the next case
the same limit switches are used during unstacking as
to enter the machine so the stacking cycles may continue.
«are used during stacking but the circuitry in which the
FIGS. 7 and 8 are schematic views of the electrical
switches are operated differs as will be evident from a
control system of the machine with FIG. 7 relating pri
consideration of FIGS. 7 and 8. Certain additional limit
marily to the circuitry of such system operative when
switches are provided when the machine is to be used for
case stacking is selected. FIG. 8 shows the circuitry =opunstacking. It will be apparent that if the machine is to
erative when unstacking is selected. A selector switch 160,
be a dual purpose machine, i.e., one which will both stack
when moved to the position shown in FIG. 7, will energize
and unstack, the additional switches necessary for the
the circuit of YFIG. 8 for unstacking operation of the
machine, and when moved to the right to the phantom
outline position shown, will de-energize the circuit of
FIG. 8 and energize that portion of the circuit of FIG. 7
below the switch for stacking operation of the machine.
As mentioned hereinabove the elevator, case locators,
case stop, and case retaining mechanism are operated by
ñuid pressure. Such pressure is derived from a suitable
unstacking operation would «be permanently a part of the
machine and while they would be actuated during cer
tain phases of the stacking operation, would have no
effect on the stacking operation.
In FIG. 1 la case stop similar to the case stop 58 here
tofore described is secured to the right-«hand end of the
machine `for the purpose of preventing or allowing entry
of stacks of cases moving on conveyor 22 toward the
pump driven by an electric motor schematically indicated 70 machine. Such case stop is of identical construction to
at 162 lin FIG. 7. Suitable iluid pressure lines extend
that of the one heretofore described and therefore a
from the pump driven by electric motor 162 tothe various
further description is believed unnecessary.
cylinders herebefore mentioned which actuate the case
One additional structural addition to the stacking ma
elevator, etc. Disposed in the pressure lines between the
chine to adapt it for unstackingis the case clamping
pump and the cylinders are solenoid operated spring re 75 mechanism 50 shown in FIGS. 3 and 4. Such mech
anism includes a pair of clamping pads ‘166 and 168, one
extension or retraction of the supporting lingers 86 and
disposed at each side of -a stack of cases in the machine
disposed between them. Such case gripping clamps are
86a. These fingers now extend beneath case C-2 to sup
port it and when they are vfully extended, serve to close
LS-7, which in turn causes the de-energization of the
Yoperable synchronously with the operation of the oase
supporting finger mechanism 48 during unstacking op
and 168.
and extensible and retractable to grip or release a case
case clamp solenoid causing retraction of the pads 166
As the first case to be unstacked leaves the
machine and strikes arm 192 of LS-lt), it closes LS-lt),
and 1.840„ in turn causing the elevator to re-ascend. The
elevator lifts case C-2 upwardly oif the supporting fingers
duplicate of that supporting the pad 168, a description of
10 86 and 36„ and when the elevator reaches the top of its
the mechanism for pad 166 will suíiice for both.
stroke, LS-ßla and LS-fi,J are closed reversing the move
As shown in FIGS. 3 and 4, pad 166 is carried by a
ment of the elevator and the cycle repeats.
pair of push rods 17 0 and 172, which yare received within
When the last case of the stack is lowered to the con
rod supporting blocks or the like 174 and 176, which are
eration in a manner hereinafter described. Because the
clamping pad 166 is carried by mechanism which is a
mounted on a plate 178 which extends across the top of
and is secured to the uprights 134 and 136. A hydraulic
cylinder 180 is mounted on plate 178 with the piston rod
182 thereof connected to the push rods by a cross mem
veyor 22 for discharge from the machine, as no case will
then be in contact with switch arm `19t), circuit 8 is set
up for the reception of the next stack of cases though the
case stop 66a does not retract until the last case of the
previously unstacked stack of cases clears out of the ma
ber 184. Upon pressurization of cylinder 180 in one di
chine and strikes arm 192 of switch LS-lti. At this point
rection, the push rods and consequently the pad 166 will
be extended while upon reverse pressurization, the pad 20 the afore-described cycle will repeat.
From the above description it is now apparent that the
>and push rods will be retracted. The pad moves between
machine disclosed herein can be used for either stacking
the solid outline position shown in FIGS. 3 and 5 and
or unstacking of cases simply by the selective positioning
‘the phantom outline position bearing against a case as
of switch »160 in the control system and by selecting the
shown in FIG. 5 or the solid outline position shown in
FIG. 6. Also included in the machine when adapted 25 direction of movement of the case conveyor 22. It will
be noted that when a stack of cases enters the machine,
'for unstacking are limit switches LS-9 and LS-dt).
Switch LS-9 is mounted on a cross member 188 which
extends between and is secured to the bearing blocks -174
those cases above the lowermost case `will come into con
tact with the stacking guides l159 and 152 which, in this
'and 176. The switch has Ian actuating arm 190` which ex
event, serve as case stack locators and interrupt the travel
the unstacking operation and in this respect is similar in
cycled during unstacking, the machine will cause unstack~
ing of stacks of cases of varying heights anywhere from
tends above the pad 166 to a point where it may be con 30 of the stack of cases through the machine. The time
delay cycle of time delay relay 'IR-2 may be so adjusted
tacted and shifted by a oase disposed between the clamps
that substantially at the same instant that a stack of cases
166 and 168. Whenever a case is disposed between the
entering the machine `cornes into abutment with guides
clamps, switch LS-9 will be actuated. LS-9 is schemati
150 and 152, the elevator will be caused to ascend to lift
cally shown in the circuit of FIG. 8. Switch LS-10 is
the stack olf of the conveyor. It will also be noted that
disposed at the left-hand end of the machine to sense the
because of the particular way in which the machine is
discharge of successive cases from the machine during
»function to switch LS-8 heretofore mentioned in con
-two or more cases in height. In the event that a single
nectíon with the stacking operation. LS-10 includes two
case should enter the machine when the machine is op
throw arms 11S-10a and 11S-«10b as shown in FIG. 8, both
erating to unstack cases, such single case will pass di
of which are closed by a case leaving the machine and
rectly through the machine without hindrance.
contacting the switch actuating arm 192.
What we claim is:
The unstacking cycle of the machine occurs as follows.
1. A case unstacking machine comprising, in combina
Stacks of cases enter the machine successively on the case
conveyor `22, the latter being operated in the direction of 45 tion: an indexing station, a case conveyor running through
an arrow U shown in FIG. l. The selector switch in the
the station, case stop means at the upstream side of said
station relative to the movement of the case conveyor,
'case locating means in the station for interrupting move
control system is shifted to the solid outline position
shown in FIG. 7 de-energizin-g the circuit of FIG. 7 be
ment of a stack of cases entering the station on the con
low the switch and energizing the circuit of FIG. 8. As
the locators 46 are in the retracted position, the leading 50 veyor, a vertically reciprocable case elevator operable
between a stack receiving position in the station and a
stack entering the machine will contact switch arm 56 to
stack elevated position above the conveyor, stack retain~
actuate LS-l which, in turn, will energize the case stop
ing mechanism disposed above the conveyor for receiv
solenoid to extend the stop 66„ to prevent the next fol
ing and holding a stack of cases raised therefrom by the
lowing stack from interfering with the leading stack in
said retaining mechanism operable to hold that
the machine. As the leading stack moves »farther into
case superjacent the case supported by the elevator dur
the machine, one of the cases will strike the actuating
ing lowering of the supported case to the conveyor and
arm 190 of LS-9 serving to energize relay CR-10 in turn
responsive to the return of the elevator to a position sup
closing relay switch Clt-10a to energize time delay relay
porting such superjacent case to release such superjaccnt
TR-‘L Upon expiration of a determined time interval,
case for lowering to the conveyor and hold the next super
TR-l will close enslaved switch TR-la to energize the
jacent case as the stack is lowered on the elevator toward
case elevation solenoid and cause the case elevator fingers
the conveyor, and said case-retaining mechanism compris
120 and `128 to lift the stack out of the indexing station.
ing case-supporting fingers extensible and retractable ad~
When the elevator reaches the top of its stroke, it closes
jacent a stack of cases to extend beneath the lowermost
switch LS-4 which, in turn, `causes the elevator to de
case of the stack to support the stack, and further com
scend. During descent of the elevator and when case
prising case-gripping pads on opposite sides of a stack of
VC-2 has reached substantially the position shown in FIG.
cases and operable synchronously with the supporting
5 during descent of lthe stack, switch LS-11 is closed
fingers to grip a case prior to the extension of the sup
energizing the clamp solenoid causing fluid pressure to be
porting fingers therebeneath and release the case upon ex
directed to cylinders 180 of both clamping mechanisms
tension of the lingers therebeneath.
to cause extension of the clamps and gripping of case C-2.
2. A case unstacking machine comprising, in combina
With case C-2 clamped and with the elevator continuing
to descend, case C-1 will continue to descend and will
be placed on conveyor 22 for discharge yfrom Vthe machine.
tion: a case indexing station, a case conveyor running
through the station, case stack retaining mechanism dis
posed above the station and including case supporting
When the elevator bottoms, it closes switch LS-S, which
serves to energize the case support solenoid controlling 75 means and case clamping means, said case supporting
ed, to the presence of the elevator at a stack-lowering
position, to cause said ñrst case-supporting means of the
case-retaining mechanism to release the lowest case of
the stack and cause the second case-supporting means to
grip the sides of the superjacent case as the lower case
descends on the elevator toward the conveyor, and re
sponsive to a determined descend of the elevator sepa
rating the case thereon from the case gripped by the re
taining mechanism to cause said first supporting means to
shift beneath the gripped case to support it.
4. The invention as defined in claim 3 characterized
means including extensible and retractable case support
ing elements at opposite Sides of a stack of cases spaced
above the station and shiftable from a retracted position
to an extended position beneath the stack to support the
stack thereon when in the extended position, said clamp
ing means disposed above the case supporting means to
grip the sides of a case disposed immediately above the
case supporting elements, said clamping means responsive
to descent of the elevator to clamp that case superjacent
the case on the elevator and responsive to an extension
of said case supporting elements beneath the clamped case
to release the clamping of the case, and said case sup
porting means responsive to the presence of the elevator
in a stack supporting position beneath a stack Supported
thereby to shift from the extended to the retracted posi
3. A machine for stacking or unstacking cases or the
in that when case stacking is selected, said control system
is operative to cause release of a case held by said re
taining mechanism independently of contact of the case
on the elevator with such retaining mechanism as the case
on the elevator approaches the case held by said retain
ing mechanism.
like comprising, in combination: a case conveyor; a case
elevator for raising cases from or lowering cases to the
conveyor; case-retaining mechanism for holding a case 20
spaced above the conveyor and including ñrst case-sup
porting means shiftable to and from case-supporting posi
tions beneath a case spaced above the conveyor, and `sec
ond case-supporting means operable to grip or release the
sides of a case spaced above the conveyor; a selective con
trol system for stacking or unstacking operation of the
machine and operatively connected to the elevator and
retaining mechanism and responsive, when case stacking
is selected, to case-elevating movement of said elevator
References Cited in the ñle of this patent
Rapisarda ____________ __ Jan. 21,
Neja ________________ __ Apr. 24,
Verrinder et al ________ __ Aug. 31,
Campbell ____________ __ Oct. 21,
Lyon _______________ __ May 5,
Hallenius ____________ __ Apr. 5,
Layott et al ___________ __ May 24,
Burt _________________ __ Aug. 22,
Belgium ______________ __ July 15, 1954
France ______________ __ Nov. l2, 1957
with a case thereon to cause release of a case held by 30
the retaining mechanism as the case on the elevator ap
proaches the held case, to allow stacking of the cases; and
said control system responsive, ¿when unstacking is select
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