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Publication numberUS3866763 A
Publication typeGrant
Publication dateFeb 18, 1975
Filing dateJul 12, 1972
Priority dateJul 12, 1972
Publication numberUS 3866763 A, US 3866763A, US-A-3866763, US3866763 A, US3866763A
InventorsFrank P Alduk
Original AssigneeFrank P Alduk
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic case stacker
US 3866763 A
Abstract
A case or carton-stacking machine is provided where one article after another is carried at properly-spaced intervals by an endless conveyor onto a vertically-movable plate that is raised and lowered by a ram or air cylinder and piston. When a carton is carried to a selected position in the apparatus, it triggers the operation of a ram that raises the article above opposed supporting dogs which then move into position below the article to keep it elevated while the ram returns to its lower level. When the next case or carton then strikes the trigger, the ram operates to raise the second one up under the first so that two articles are then supported, one above the other, on the dogs. This cycle repeats until the stack reaches a predetermined height when the dogs are held out of stack-supporting position and the stack is lowered with the ram until it rests on the endless conveyor and is removed. Provision is also made for removing the stack while it is supported on the dogs when the stack is to be removed at a level above the conveyor level. For stacking cartons with cover flaps, a coverflap-closing unit is attached to the stacker.
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United States Patent [1 1 Alduk [4 1 Feb. 18, 1975 1 AUTOMATIC CASE STACKER Frank P. Alduk, 1 16 Guadalcanal Rd., New Castle, Pa. 16105 [76] Inventor:

[52] US. Cl. 214/6 BA [51] Int. Cl. t B65g 37/30 [58] Field of Search 214/6 BA, 6 P

[56] References Cited UNITED STATES PATENTS 2,857,040 10/1958 Campbell 214/6 BA X 2,904,941 9/1959 Midnight 214/6 BA X 3,039,624 6/1962 Campbell 214/6 BA 3,053,402 9/1962 Russell et a1. 214/6 BA 3,057,486 10/1962 Moulthrop et al. 214/6 BA 3,126,104 3/1964 Haselton et al. 214/6 BA 3,305,104 2/1967 Hogan et al. 214/6 BA 3,519,144 7/1970 Calistrat 214/6 BA 3,570,209 3/1971 Salwasser 214/6 BA 3,643,817 2/1972 Rose .i 214/6 BA Primary ExaminerRobert J, Spar Assistant Examiner-Leslie .I. Paperner Attorney, Agent, or FirmParmelee, Miller, Welsh & Kratz [5 7] ABSTRACT A case or carton-stacking machine is provided where one article after another is carried at properly-spaced intervals by an endless conveyor onto a verticallymovable plate that is raised and lowered by a ram or air cylinder and piston. When a carton is carried to a selected position in the apparatus, it triggers the operation of a ram that raises the article above opposed supporting dogs which then move into position below the article to keep it elevated while the ram returns to its lower level. When the next case or carton then strikes the trigger, the ram operates to raise the second one up under the first so that two articles are then supported, one above the other, on the dogs. This cycle repeats until the stack reaches a predetermined height when the dogs are held out of stack-supporting position and the stack is lowered with the ram until it rests on the endless conveyor and is removed. 'Provision is also made for removing the stack while it is supported on the dogs when the stack is to be removed at a level above the conveyor level. For stacking cartons with cover flaps, a coverflap-closing unit is attached to the stacker.

17 Claims, 15 Drawing Figures v I PATENTEUFEBI 81975 sum 1 OF 5 m9?" 3 PATENTED a SHEET am: 3.866 76 PATENTEB m1 81975 sum a 05 5 PATENTEU FEB] 8 75 SHEET t [IF .5

AUTOMATIC CASE ST ACKER This invention is for a machine for automatically stacking single units, such as cases, cartons, boxes, or packages of various kinds one on top of another to facilitate handling or conserve space and thereby avoid much of the manual labor heretofore required in stacking the units.

A machine of the general type to which the present invention relates is disclosed in U.S. Pat. No. 2,857,040 to W. S. Campbell, granted Oct. 21, I958 for an Automatic Case Stacker, but which, so far as I am aware, was never developed into a commercial machine, and which appears to be impractical.

The present invention provides a machine to which units to be stacked are delivered in succession by conveying means where they are admitted one at a time to a mechanism that raises them one under another until a stack of the desired height has been formed. When this height is reached, the entire stack is then normally conveyed to the discharge end of the machine. As each unit is raised up, supporting dogs at each side of the machine move from the path of the ascending unit. As the air cylinder or ram which lifts the unit lowers, these dogs move into a position where the units are supported on the dogs while the lifting means descends to receive the next unit. When the stack has reached the selected height, these dogs may be held out of stacksupporting position so that the whole stack is lowered onto the conveying means which thereupon carries the stack to the discharge end of the machine. However the machine may be selectively modified so the dogs support the completed stack and the stack is removed from the machine at a level higher than the said conveying means.

Unlike the machine shown in said Campbell patent, the ram always operates on the same cycle, whether it is raising the first unit of a stack or the last. Also unlike said patent the supporting dogs are mechanically moved to and held in an inoperative position when the stack is being lowered to the conveying means. Accidental premature operation of the ram cannot take place. Readily-made adjustments enable one machine to stack units over a wide range of sizes, so that a custom-built machine is not required for each size of unit. As above indicated, the one standard machine can be quickly adapted to deliver the stack of units at a level higher than the conveyor that brings the individual units to the stacker, and completed stacks may be selectively removed from either end or either side of the machine.

The machine may also have a carton flap-closing attachment whereby it may accept for stacking those cartons in which some or all of the cover flaps are only partly closed.

In the drawings showing a preferred embodiment of my invention with certain modifications to be used where the operation makes it desirable to do so:

FIG. 1 is a side elevation of the machine;

FIG. 2 is an end elevation from the receiving end of the machine with the restraining device removed and certain parts broken away for illustration with a cast, shown in broken lines, in position for the starting of a stack of cases;

FIG. 3 is a view similar to FIG. 2 showing the case of FIG. 2 elevated;

FIG. 4 shows a plan view of the bed of the machine, the view being a horizontal section in the plane of line IVIV of FIG. 2;

FIGS. 5, 6, 7, 8 and 9 represent somewhat schematically the progressive operation of the machine in forming a stack of three cases or cartons following the operations shown in FIGS. 1 and 2;

FIG. '10 is a view similar to FIG. 2 but on a smaller scale showing a modification in which the case is removed from the apparatus at a level above the case conveyor and in a direction at right angles to said conveyor;

FIG. II is a fragmentary detail view of one of the case-supporting dogs and its operating mechanism;

FIG. 12 is a view similar to FIG. 11 of a modified case-supporting dog;

FIG. 13 is a fragmentary side elevation similar to FIG. 1 showing in outline a conventional carton flapclosing arrangement;

FIG. 14 is a fragmentary side elevation of one side of the stacker of FIG. 13 with a roller instead of a weight for pressing down on the completed stack; and

FIG. 15 is a schematic diagram of one air systemfor operating the apparatus shown in FIGS. 1 to 11.

In the drawings, 2 designates generally a rigid frame formed largely of hollow square tubing or other struc tural sections 3 substantially coextensive with the length of the machine. For purposes of this description, and as here illustrated, the left end of the machine is the entering or receiving end and the right end the discharge or delivery end. Also, while the machine is here described as a case stacker," the term case is used in a general sense to include not only cases in which bottled carbonated or other beverages are contained, but boxes, cartons, packages or other units of various shapes suitable for handling in a stack, one on top of another, and cartons which may be closed or have partially-open flaps that are required to be closed. Also a stack may comprise two or more articles placed one on top of another, or two articles entering the machine side-by-side or end-to-end as a single unit and stacked pair-on-pair in this relation.

At the left or entering end of the machine there is a transverse shaft 4 with spaced sprocket wheels 5 thereon and the opposite end there is a similar shaft 6 with sprocket wheels 7 thereon. Spaced endless tread type conveyor chains 8 pass around these sprockets, one near each side of the horizontal center line of the machine. The shaft 6 is motor-driven, as indicated by the motor 9 and sprocket chain 10, this chain passing around sprocket wheel 11 on the shaft 6. Being thus driven, the upper reaches of the conveyor chains are taut and any slack is in the lower or return reaches, as indicated in the drawings. Also, as indicated in the drawings, there is a longitudinally-extending supporting rail, not numbered, under the upper reach of each conveyor chain, as is usual with conveyors of this type. The width between the two conveyor chains 8 is fixed, but there is a guide bar 12 adjustably supported above and along the outer side of each conveyor chain 8 for adjustment toward and away from each other to accommodate, center and guide units of different widths. To provide such adjustment, each bar 12 has at least two rigid supporting arms 13 fixed thereto and extending laterally therefrom toward the outer side of the frame which is nearest the bar 12. Each arm passes through a support 14 and is slidably fixed in place by a set screw, as indicated at in FIG. 1. The supports 14 near each end of the machine are fixed on a transverse bar 16 and releasably held in place by a set screw 17. Thus bars 12 may be adjusted toward and away from the center of the machine by loosening set screws 15 and sliding the rigid lateral arms in their respective support members 14.

As best seen in FIGS. 2, 3 and 4 there are continuous support plates 18 along the outside edge of the top reach of each conveyor chain 8 and the proximal side rail 3, the surface of which is close to but slightly below the level of the conveyors. There are two similar short plates, 19a and 19b between the two conveyors at opposite ends of the machine, but which have their confronting ends spaced from each other for the purpose hereinafter described.

Over the mid-section of the supporting frame 2 there is a vertically-elongated structural frame, designated generally as 20, having a pair of upright columns 21 facing toward the left or receiving end of the frame and a pair of similar columns 22 facing toward the right or discharge end. These columns extend up from and are secured to the horizontal side rails 3 of the machine frame. The tops of the columns of each pair, such as the pair of columns 21, are connected by transverse rigid sections 23 and each pair of columns on the same side of the machine, comprising one column 21 and one column 22 are connected at the top by a longitudinallyextending rigid section 24.

The columns 21 and 22 are each provided with a series of closely-spaced holes 25 therethrough extending in the direction of the length of the machine, or what may be termed a fore-and-aft direction, the holes on each column or post being level with corresponding holes on the other three columns or posts.

In the area between the spaced ends of the plates 19a and 19b, which is the area centered beneath the upright frame just described, there is an inverted U-shaped structure 30 (see FIG. 1) with a flat top or platform 31 that is normally level with plates 19a and 19b and with depending legs 32. As seen in FIG. 4 the flat top 31 substantially fills the space, with adequate working clearance, between the spaced ends of plates 19a and 19b. This structure 30 is fixed to the top of a fluid pressure ram or piston rod 33 of a fluid pressure cylinder and piston unit 34 so that the plate or top portion 31 can be raised from its normal position to a level as shown in FIG. 3 where the piston rod is fully extended.

In the operation of the machine it is expected that the conveyor chains will carry a case or other unit onto the flat plate 31 at which time pressure air will be admitted to a cylinder 34 to raise the unit up between opposed supporting dogs which permit upward movement of said unit but support it in an elevated position when the support 31 is again lowered. The next unit in turn will be lifted in the same way contacting the under side of the first one, and the two will be lifted together until the second unit is also clear above the supporting clogs, when the ram will lower and the two units, with the first resting on the second, are then both supported by the dogs. Suppose a stack threecases high is to be formed, the third unit will be raised under the first two and all three will then lift together, but the first unit, on top, will now be raised to a level where it triggers a release to keep the supporting dogs inactive and the stack of three units will be lowered with the ram to the conveyor which will carry the stack to the discharge end of the machine and the next stack of three will start to form. The mechanisms for doing this will now be described.

CASE FEEDING AND LIFTING When a case, carton or other package unit to be stacked is delivered from a feed conveyor as indicated or other supply means at the left end of the machine onto the receiving end of the conveyor of the stacker, other parts of the machine must be in a position to take care of it. Therefore the plate 19a has on opening therethrough through which a stop-member may be projected from a non-obstructing level below the plate 19a to a position above said plate midway between the two conveyor chains where it will restrain a case, carton, or other object from further travel even though the conveyor chains continue to operate. The stop member 40 is mounted on and moved up and down by a doubleacting cylinder and piston unit 41 which is preferably air-operated. The introduction of air into the bottom of the cylinder raises the stop and admission of air to the top of the cylinder lowers the stop.

To properly space the carton or other unit and prevent one from continuing to move until the previous one has been taken care of, a flag switch or trigger 42 is positioned along the plate 19a a few inches beyond the stop 40, so arranged that when the leading end of the case strikes it, an air valve will be operated to admit pressure air to the lower end of cylinder 41 to raise the stop 40 to block the travel of a succeeding unit.

A case which has passed the stop 40 is carried by the conveyor onto the plate 31 at the top of the ram cylinder 34. At the end of plate 34 there is a stop member 43 generally similar to stop 40 which is raised and lowered through an opening in plate 19b by an air cylinder and piston unit 44, but unlike stop 40, stop 43 is normally raised to case-obstructing position. Admission of air to the top of the cylinder of the unit 44 lowers the stop and to the bottom of said cylinder the stop 43 is raised to the stop position.

The stop member 43 has an air valve, trigger,- or other self-closing flag switch 45 on that face which confronts the leading end of an advancing unit, and when a unit has moved sufficiently far over plate 31 its forward or leading end will strike this member 45, so that in addition to the unit being stopped from further travel, pressure air will be supplied to the lower end of the ram or lifting cylinder 34 to lift the unit. There is an abutment or finger 46 on one leg 32 of the inverted U-shaped structure 30. At 47 there is a fixed upright channel on which are upper and lower limit switches or valves 48 and 49 respectively, 48 being arranged to be engaged by this finger. The upper valve 48 is adjustable up and down on the upright 47. When the finger 46 strikes this switch, the upward movement of the ram is stopped and its downward travel initiated.

Lower switch 49 is positioned to be tripped on the down stroke of the ram, near the lower limit of its travel, and its function is to effect the lowering of the stop 40 so that the next unit can be carried into position over the ram when the ram is back down to its lower limit of travel. While it might be arranged that finger 46 also trips valve 49, this operation is preferably effected by valve operator 50 on the leg 32 below the finger 46, and hence trip the valve 49 a little sooner so that the next unit may actually start to move toward the ram a little sooner on the down stroke of the ram. Valve operator 50 is designed with a finger arranged to ride past switch 49 on the upstroke and trip the valve only on the down stroke. By adjusting the position of the limit switch 48 the stroke of the ram may be decreased or increased as required for high or low cases or other units.

THE LIFTED UNIT SUPPORTS OR DOGS When a case or other unit has been lifted by the upward movement of the ram, it must be removed from the plate 31 and supported at an elevated level until a stack is formed. This is accomplished by shelf-like supporting dogs selectively fixed at the desired elevation on the upright frame 20, one at each side of the machine. The higher the cases or other units, the higher are the dogs set above the conveyors. Also there are guides above these dogs at each side of the machine for keeping the cases centered one above the other and stabilizing the stack as it is being formed.

As shown in FIGS. 1, 2, 3 and 11, these dogs each comprise a metal tilt plate 60 welded to the under side of a rock shaft 61 so that each may swing in a vertical arc. Each plate is unbalanced on the shaft 61 with the unbalanced overhanging end projecting laterally toward the longitudinal center line of the machine. The rock-shaft is supported at each end in a bearing 64, the bearing at one end being carried on a supporting plate 65 and at the other end on a similar plate 66. The plate 65 for each dog is supported on one of the upright columns 21, one at one side of the machine and one at the other. Similarly plates 66 are bolted to their respective columns 22. The bolts 67 pass through selected holes 25 in the columns on which the plates are mounted so that all four supporting plates are at the same level, and the bolts pass through elongate slots 68 in the respective plates 65 and 66 so that the two plates 65 may be adjusted toward and away from each other and the plates 66 are similarly adjustable. The tilt plates or dogs 60 are restrained from dropping below a horizontal position by an angular bracket 69 on the plates 65. Each of said plates 60 has notches 70 in that edge which is toward the center of the machine to clear the guide bars which are hereinafter described.

With this arrangement the dogs 60 at each side of the machine can be adjusted vertically as required by the height of the units and toward and away from each other and symmetrically with respect to the longitudinal axis of the machine as required by the width of the units.

Above the dogs and their supporting plates there are four other plates 71, one on each of the posts or columns 21 and each of the posts or columns 22. These plates are bolted to their respective posts for vertical adjustment by selection of the proper holes 25 and have elongate horizontal slots 72 therein for adjustment toward and away from each other. The two support plates 71 at each side of the machine are joined by a connecting rail 73 parallel with the longitudinal axis of the machine. Each connecting rail in turn carries two vertical parallel guide bars 74 with outwardly-flared lower terminal portions 75. These bars center and stabilize the stack as it is being formed, as hereinafter more fully appears. In the drawing, for purpose of illustration, they are illustrated above their normal level, since, at the normal level the notches 70 are provided in the dogs to clear the lower ends of these rods when the dogs swing up.

When a case is lifted by support 31 and ram 32 it pushes up against the overhanging edges of the two dogs or hinged plates 60, swinging them in a vertical arc upwardly, but their edges bear against the sides of the case, since they are overbalanced or biased to return to the horizontal position. When the case clears the upper edges of the dogs they swing down to a horizontal position but they are so spaced that they do not project inwardly toward the longitudinal center of the machine far enough that they can project under the plate 31; in fact the legs 32 are guards against any such possibility. At this time the ram reverses and as it lowers, the dogs, projecting under the edges of the case, will support the case against further downward travel.

When a second case follows, it will be pushed up in like manner, lifting with it the first case, and as the ram lowers, the first case will be on top of the second one and the second one will be supported on the dogs. This stacking by adding one beneath those above will be repeated until a stack of the desired height, stabilized between the guide bars 74, has been reached. The guide bars can be adjusted as needed to meet the dimensions of the cases or other units.

STACK REMOVAL Let it be supposed, for example, that the stacks are to each be three units high. As indicated in'FIG. 6, the first two units will be supported on the dogs as above described and indicated C and C The third unit, C is carried by the conveyors directly beneath these two, where it will be raised by the ram in the manner described until it, too, is above the top edges of the dogs 60. By this time, the total stack of three units will be so high that C will strike and lift the terminal of a rod 81 adjustably fixed to and depending from a lever 82. The lever 82 extends outwardly from a pivoted cam disk 84 fixed for selective vertical adjustment on one of the upright columns 22. As the terminal 80 pushes up on rod 81 the disk 84 will rotate, the direction of rotation being indicated as clockwise by the arrow in FIG. 2. The cam element 85 on the periphery of this disk will operate air valve or switch 86.

It will be noted, and as best seen in FIG. 10, that each one of the two mounting plates 65 has a horizontallypositioned air cylinder fixed thereto with a pistonoperated piston rod 91 having a free terminal element 92 thereon. Air pipes 93 and 94 supply pressure air to move this piston to the right or left, respectively, as viewed in FIG. 10.

At the instant valve 86 is tripped by the raising of lever 82, pressure will be supplied by such action of the valve 86 through pipe 93 to move the piston of cylinder 90 toward the right, as here shown, pushing the terminal 92 against the edge of plate 60 below the pivot shaft 61 to move the plate 60 to a position where it is entirely clear of contact with the units in a stack and hold it nearly vertical so that it cannot fall back to the loadsupporting position. It should be kept in mind that there is such a mechanism on each of the two mounting plates 65, both controlled by the one valve 86. With the dogs 60 thus held in an inoperative position the stack of three cases will be lowered with the lowering of the ram-supported plate 31.

When the valve 86 is tripped, it will also supply pressure air to the top of cylinder 44 to lower the stop 43 to its inoperative position so that as the bottom of the stack comes to rest on the conveyor chains 8 the stack will be carried by the conveyors toward the delivery or discharge end of the machine. Since the finished stack is moved out of the upright frame by the same conveyors that advance a new case for the start of the next stack, there is no problem of the likelihood of a new case being moved into position to start the next stack until the completed stack is sufficiently clear of the upright structure 20. There is another switch or air valve 100 similar to 42 below the plate 19b and located a short distance beyond the stop 43. It is arranged to be engaged by the leading edge of the stack. When this valve is operated the stop 43 will be raised, and the two cylinders 90 will be operated to withdraw the terminals 92 of the piston rods 91 from contact with their respective dogs 60 so that by their over-balance, they will drop to their horizontal position. The lever 82 with its rod 81 and terminal 80, being weight-biased, will swing back to its normal position shown in FIG. 2 where a fixed supporting pin 81a prevents it from dropping below a predetermined level. These operations, having all taken place, the machine will be ready to start the next stack when the next unit, which may have already cleared stop 40, reaches stop 43 with its trip valve 45.

It should be noted that the dogs 60as seen for example in FIG. 2must be above the level of the top of unit C sothat the unit'may travel under them to engage trip valve 45. Hence vertical adjustment of the dogs to clear higher cases or cartons, or whatever is being stacked is important. If, however, these plates were at a fixed height above the highest unit so that any case of a lower size could pass under it, there would not only be lost motion, slowing the cycle for lower cartons, but whereas it may be practical to form a stack which is only three cases high with boxes or cartons, it may be desirable to stack seven or eight shallow wide boxes. Adjustment of the elements for various heights and widths therefore increases substantially the utility of the machine and decreases cost, since a customer can order a machine from stock and not require a custom-built machine for his particular size of unit, and if he has a run of one size and then another, he can quickly adjust his machine to the requirements of the different sizes of units.

The air system for effecting the various operations is conventional and comprises standard equipment which is well known to those skilled in systems of this kind. FIG. 15, for purpose of illustration, shows schematically a simplified circuit for the machine described. Referring to FIG. there are three main four-way sliding valve units 105, 106, and 107 to which pressure air, regulated and controlled as usual, is supplied from a source (not shown) through pipe 108, and branches 109, 110 and 111 respectively.

The first valve supplies the air to cylinder 41 for rais-' ing and lowering the stop 40. When valve 42 is momentarily depressed, pressure is relieved in pipe 42a causing the valve element of unit 105 to move to a position where pressure air is supplied through pipe 41a to raise the stop while pressure in the top of the cylinder 41 is relieved through pipe 41b. When valve 49, operated as the ram reaches its lowermost position is tripped, relieving pressure in this line, valve 105 moves in the reverse direction to supply pressure air to the top of cylinder 41 through pipe 41b and relieve pressure at the lower end of said cylinder through pipe 41a.

The second valve 106 directs the flow of air to operate the ram. When valve 45 on stop 43 is tripped, it releases pressure in line 45a, causing valve 106 to move to a position where pressure air is supplied through pipe 340 to the lower end of cylinder 34 to lift the ram, and air from the top of the cylinder will be exhausted through line 34b. When the ram has lifted to trip valve 48, valve 106 will be shifted to reverse this flow and lower the ram.

Valve 107 does two things. It supplies air to cylinder 44 to move stop 43 up and down and to the cylinder that control the hold and release of the dogs. When stack height limit switch 86 is tripped, valve 107 is operated to supply pressure air through pipe 93a to pipes 93 to actuate the dog-holding devices 92 to operative or hold position. It also supplies air through pipe 44a to lower the stop 43.

When switch is tripped, valve 107 reverses the pressure air which is directed through pipe 44b to cylinder 44 to raise stop 43. At the same time pressure air is supplied through pipe 94a to pipe 94 to the ends of cylinder 90 to retract the dog-holding terminals to the position where dogs 60 can drop to their horizontal position.

In some instances the trip valves may be electric switches that would electrically operate the air valves or solenoids to accomplish the functions of airoperated mechanisms, as is also well known in the art. horizontally-movable Instead of using hinged dogs as shown in detail in FIG. 11, it may be desirable in some cases to use horizontally-sliding dogs, as shown in FIG. 12 which illustrates one end of one of a pair of such dogs. There is a supporting plate 65 similar to plate 65 in FIG. 11. Each supporting plate has a pair of vertically-spaced ears 110 which slidably support one end of a horizontallydog 111. There is an air cylinder 112 similar to air cylinders 90 with air pipes at each end similar to cylinder 90. The piston rod 113 of the piston in cylinder 112 is connected at 114 to the dog 111 for reciprocating said dog horizontally.

The function of the sliding dogs 111 is generally the same as the function of dogs 60, but the air valving is such that when the trip 45 is activated, the cylinders 112 will be operated to withdraw the dogs from the path of the upwardly-rising plate 31 with the case which is on it, thereby allowing this case to be moved to a level above the dogs. When air valve 48 is tripped, the dogs on opposite sides of the machine will slide toward each other by reverse operation of cylinder 112 and its several counterparts, but not sufficiently for the dogs to interfere with the downward travel of the ramsupported plate or platform 31. In brief, the sliding dogs operate each time a case is raised, but when the height valve 86 is tripped, the dogs will not move inwardly to package-supporting position until the trigger 45 is next operated for the start ofa new stack. One advantage of this arrangement over the hinged dogs of FIG. 11 is that each case does not need to be lifted as high where the dog slides horizontally.

In some instances it may be desirable to remove the stack at a level above the level of the case conveyor chains 8, either in the same direction as that in which the chains are moving, or in the reverse direction or to one side or the other at 90 to the direction in which said conveyors travel. In FIG. 10 this is illustrated with the stack removal being onto a stack removal conveyor 115 at the left side of the machine as here diagrammed. For this purpose the upwardly-swinging hinged dogs 60 are at right angles to the position shown in FIGS. 1 to 3. There is a pusher plate 1 16 operated by a fluid pressure cylinder-piston unit 117 which is normally in a retracted position at the right of the vertical frame at a level clear of the top of dogs 60 when they are in the horizontal position and which is short enough, or otherwise so arranged, that the pusher plate in its retracted position does not interfere with the upward swinging of the dogs 60 or upward travel of each case as it is raised by the ram in the manner heretofore described. The cylinders 90 to momentarily hold the plates vertical as the stack is clearing the frame are not required in this instance, but when the stack height switch 86 is tripped, as heretofore described, it will effect the operation of the pusher plate by operating cylinder-piston unit 117 to drive the pusher to the left as here illustrated to discharge the stack onto stack-removal conveyor 115. In this instance there may be a flag switch 118 positioned to be operated by the emerging stack to take the place of flag switch 100 on plate 19b.

If the stack is to be discharged to the right of the upright frame 20 instead of the left, the parts above described are simply shifted 180, but if the stack is to be removed in the direction of the travel of the conveyor chains or opposite thereto but at the higher level, the dogs extend in the same direction as shown in FIGS. 1 to 3 but the pusher arrangement, flag switch 118 and conveyor 115 will be disposed lengthwise of the machine but elevated above the conveyor chain 8 the required'height.

In many places where a stacking machine of this kind is needed, cartons to be stacked are delivered to the machine with en and side flaps incompletely closed, and if they were moved toward the stacking area in this condition the flaps, especially the side flaps, would jam against the dogs 60 or 111, as the case may be, and possibly cause damage to the cartons, or the machine or the product in the cartons. With hinged dogs 60 the first such carton might hinge the dogs upwardly, but after one carton was then supported on the dogs, the second carton could not enter. To prevent this, the vertical structure 20 may also support a carton flap-closing unit of any preferred or conventional form as indicated in FIG. 13. Here the carton-closing device is indicated generally as 120. It is adjustably secured to the frame 20 on that side of the frame. which faces the oncoming traffic. It has the conventional guide member 121 that presses down the small inside flap at the front of the carton. There is a cylinder-powered flap-folding element 122 on a lever 123 that is swung in an are about pivot 124 by a pressure cylinder-piston unit 125 on a bracket 126. It swings in between the two partially open side flaps of the carton and depresses the end flap of the carton at the trailing end of the carton. Two fixed curved shoes or guides 127, only one of which is seen in the drawings, are positioned to depress the two side flaps, in a manner well understood in the art and hold them down, overlapping the end flaps until the carton moves under the dogs 60, or 111 in position to be lifted.

Also the flap-closing device 120 will have associated therewith glue applicators (not shown) for applying glue to the top of the end flaps so that the side flaps will be glued shut as they are folded down, or glue may be so applied before the cartons are delivered to the stacker. Also, it may often be desired to glue one unit in a stack on top of another by a severable glue. In this case glue is not applied to the outside of the side flaps of the first carton in a stack, but would be applied to the tops of the succeeding cartons of the same stack so that as each succeeding carton was pressed against the bottom of the carton above, the two cartons would be glued together. This involves only conventional glue applicators.

For applying pressure to the'flaps after they have been glued, and to cartons in the stack if the cartons in the stack are glued to one another, there is a floating weight in the frame 20 suspended from one or more guide rods 131 slidable through the top of the frame, with a limiting nut or other abutment 132 at its upper end to limit its downward movement. As each carton is lifted the top carton presses against the weight 130 and lifts it and then as the weight follows the completed or incompleted stack down it continues to exert pressure. Only a brief time is required for the glue to set.

In place of the floating weight just described, there may be a pressure roller 135 on the frame 20 at the outgoing side beneath which the stack, as it leaves the frame 20 must pass and be momentarily pressed between the roller at the top and the conveyor and table structure at the bottom. The flap-folding arrangement of FIG. 13 would of course be used along with some kind of gluing applicators, as previously described in FIG. 13. With the arrangement shown in either FIGS. 13 or 14, the conveyor chains may require upstanding flights on the conveyor chains to positively push the cartons under the flap-closing device, in which case the trigger 45 stops the conveyor belts and 49 starts them. In this case stop 40 may not be necessary.

While case or like stackers of this general type have heretofore been proposed, the present invention embodies certain novel concepts in a relatively inexpensive machine. One is the ready adjustability of the machine to stacking cases or cartons of different widths and different heights. The location of the switches 48 and 49 to be operated by the inverted U-shape frame 30 with switch 48 being adjustable up or down to regulate the travel of the ram and the frame to suit the thickness of the cases being stacked assures that this switch or valve cannot be accidentally tripped. The machine is unique in that the lowermost carton in the stack is lifted by the ram the same distance as each of the other cartons in the stack. This avoids the necessity of providing for a shorter stroke or different cycle of the ram when the stack has reached its full height, and whether the hinged dogs 60 or the sliding dogs 111 are used, these dogs are held clear of the sides of the stack when the stack is moved out of the frame 20 to the discharge end of the machine. Moreover this same facility enables the stack to be removed at a level above the level of conveyor chains 8 so that one machine, with little expense, such as the addition of the pusher arrangement of FIG. 10 can be adapted to various plant environments or requirements, providing great versatility without each machine being custom-built for the shop in which it is to be used. By providing the carton flap-closing unit immediately in advance of the stacking mechanism a further important utility is provided. The floating weight arrangement of FIG. 13 or the pressure roller of FIG. 14 is of considerable importance where carton flaps are to be glued, or the cartons in a stack glued together. The pneumatic circuitry and valves are standard equipment, as are the cylinderpiston units so that the machine can be assembled from standard structural sections and off-the-shelf parts with very little machine work being required. By having parallel conveyor chains with the supporting plates 18, 19a and 19b, together with adjustable guide bars 12, two smaller units may be stacked side-by-side as a single unit, and at other times two smaller units may be placed in abutting end-to-end position and stacked as a single unit. Also, while in the specific examples here used the stack comprises more than two units, in many instances a stack will be but two units high.

I claim:

1. Apparatus for arranging similar units into vertical stacks of predetermined height comprising:

a. a supporting frame with parallel sides and with a horizontally-extending conveyor means thereon comprising two parallel endless conveyors, one near each side of the frame with a space between them, the frame and conveyor having a receiving end onto which units to be stacked are placed in succession and a delivery end opposite the receiving end,

b. elevator means on the frame intermediate the two ends thereof and positioned in the space between the two endless conveyors, said elevator means having a platform which has a lower position over which units to be stacked are carried in succession by the conveyor means arranged to elevate each unit in turn to a selected uniform level above the conveyor means, with each succeeding unit after the first in a stack being raised underneath the one ahead until the stack comprises a predetermined number of units and is of a predetermined height, the elevator comprising also a fluid pressureoperated ram on which the platform is fixed and by which it is moved vertically,

c. said frame having upwardly-extending frame members at each side thereof between which the elevator lifts the units to form a stack, the side frame members each having a unit-supporting dog thereon with the dog on one side being directly opposite the one on the other side, said dogs being movable in a vertical arc between a position where they are clear of the upward travel of the elevator platform but project under a unit raised above the level thereof by said platform to a position entirely clear of any contact with the units, there being horizontally-acting cylinder and piston units arranged to move and hold said dogs in position where they are entirely clear of any contact with the units and effecting their return to a position where they may extend under a unit that has been elevated by the platform,

d. fluid pressure-actuated means controlled by the height of the stack of units above said dogs for selectively holding said dogs out of unit-contacting position whereby the completed stack may then be lowered into said conveyor means to be carried thereby to the delivery end of the conveyor.

2. Apparatus as defined in claim 1 in which said means for holding the dogs out of unit-contacting position is rendered inoperative and a pusher means is arranged to slide each completed stack while it is supported on said dogs at an elevation above the level of the conveyor means.

3. Apparatus as defined in claim 2 where the dogs are crosswise of the conveyor means and said pusher is arranged to push the completed stack to one side of the supporting frame in a direction transverse to the direc-v tion of travel of the conveyor means.

4. Apparatus as defined in claim 1 in which said dogs each comprise a pivoted plate biased to swing to a horizontal unit-supporting position but is free to swing upwardly by contact with a unit being lifted by said elevating means, and wherein means is provided for restraining each of said dogs so biased from swinging down to the horizontal unit-supporting position, the apparatus having means actuated by contact with the stack only when the stack has reached a predetermined height for operating said restraining means to keep the dogs from swinging down to load-supporting position whereby the completed stack may then be lowered past said dogs onto the conveyor means to be carried thereby to the delivery end of the conveyor, and other means effective upon travel of the completed stack toward said delivery end for releasing said dog-restraining means whereby the dogs are restored to a free-swinging condition for the forming of the next stack.

5. Apparatus as defined in claim 1 in which the dogs and the horizontally-disposed cylinder and piston units for the respective dogs are mounted for adjustment horizontally toward and away from each other and vertically with respect to the conveyor to thereby accommodate units of different widths and different heights, the frame having transversely-adjustable longitudinally-extending guide rails at each side thereof, the adjustment of which enables units of a preselected width to be kept centered over the elevator platform.

6. The apparatus defined in claim 1 wherein said elevator platform has a depending leg element thereon which has a laterally-projecting flag switch-engaging means thereon, and a pair of vertically-spaced flag switches positioned on the frame to be operated by the movement of the projection on said leg past said switches, the upper flag switch being arranged to reverse the travel of the ram when it has reached the predetermined level above the conveyor and the lower one of which is arranged to operate a control means for passing the units one at a time to the elevator, said upper flag switch comprising the only ram-operated means for reversing the travel of the ram.

7. Apparatus as defined in claim 6 wherein the upper flag switch is vertically adjustable in the frame to adjust the extent of up and down travel of the ram.

8. Apparatus as defined in claim 1 wherein said conveying means comprises a pair of parallel endless chain conveyors driven together as a unit but spaced from each other and from the sides of the frame and there is a vertical frame structure extending upwardly from the sides of the supporting frame at each side of said unit-elevating means, the opposed dogs being supported on said vertical frame structure at each side of the frame, and means on said vertical frame structure projecting toward the receiving end of the conveyor means for folding down all the flaps of a unit which is a carton to a level below the level of the dogs so that the unit may be conveyed under said dogs onto the elevating means.

9. Apparatus as defined in claim 8 in which the dogs are vertically adjustable on the vertical frame structure and the flap closure is also vertically adjustable.

10. Apparatus as defined in claim 8 wherein the vertical frame structure has a weight slidably suspended from the top thereof in position to be engaged and lifted by the stack as it is being progressively formed and thereby exert a pressure on the closed carton flaps to hold them down while glue may be setting or if one carton is being glued atop another.

11. Apparatus as defined in claim 1 wherein said vertically-extending side frames also support means extending toward the receiving end arranged to fold down the flaps of a unit where such unit is a carton with flaps incompletely closed to an extent where the flaps will be at a level below the dogs when the unit moves into position over the elevator platform.

12. Apparatus for arranging similar units into vertical stacks of predetermined height comprising:

a. a supporting frame with parallel sides and with a horizontally-extending conveyor means thereon comprising two parallel endless conveyors, one near each side of the frame with a space between them, the frame and conveyor having a receiving end onto which units to be stacked are placed in succession and a delivery end opposite the receiving end,

b. an elevator on the frame intermediate the two ends thereof and positioned in the space between the two endless conveyors, said elevator having a platform which has a lower position over which units to be stacked are carried in succession by the conveyor means and arranged to elevate each unit in turn to a selected uniform height above the conveyor with each succeeding unit in the stack after the first one being raised underneath the preceding one until the stack comprises a predetermined number of units and is of a predetermined height, the elevator comprising also a fluid pressureoperated ram on which the platform is fixed and by which it is moved vertically,

c. a vertically-movable stop means normally positioned to stop each unit as it moves in position over the elevator to be lifted, said stop means being movable from said normal position to a position out of the plane of travel of a unit supported on the conveyor means, said stop means having a first trip means thereon arranged to be operated when the stop means is in normal position by a unit which is carried by the conveyor means contacts it, said trip means being arranged to energize the ram to effect the raising of the elevator,

d. elevator control means arranged to always reverse the upward travel of the elevator at the same preselected level comprising a second trip means on the frame below the elevator, and means on the elevator below the platform for operating said second trip means on the upward travel of the elevator to thereby effect the lowering of the elevator back to said lower position, said second trip means comprising the only means responsive to the travel of the elevator including any stack which it lifts for reversing the travel of the elevator,

e. said frame having upwardly-extending frame members at each side thereof between which the elevator lifts the units to form a stack, the upwardlyextending side frame members each having a unitsupporting dog thereon pivoted to swing in a vertical arc with the opposing dogs positioned to clear the path of travel of the elevator platform but to be engaged and swung upwardly from a horizontal position toward a vertical position by contact with a unit being lifted by the elevator, said dogs each being biased to swing back to a horizontal position where they each project under a unit after the elevator platform has moved to a level above the tops of the supporting dogs, whereby the dogs support the bottom of each unit in turn as it is lifted by the elevator and the elevator then descends,

f. a second trip means in position to be engaged by the top of the stack as the last unit is lifted into place and arranged (l) to move said verticallymovable stop and its said first trip out of unitobstructing position, and (2) move and hold said dogs in a nearly vertical position clear of contact with the units of the stack and prevent their moving to a horizontal load-supporting position whereby the stack of units may then be lowered by the elevator platform onto the conveyor means to be carried without obstruction from said stop toward said delivery end, and

i g. means in the path of travel of the stack between the vertically-movable stop and the delivery end of the conveyor for restoring said stop with its first trip means into unit-obstructing position and simultaneously release said dogs whereby they may return to their horizontal position.

13. Apparatus as defined in claim 12 for arranging similar units into a vertical stack of predetermined height wherein each said vertically-swinging dog is moved to the nearly vertical position out of contact with the units and its return to a horizontal position is effected through a horizontally-disposed fluid pressure cylinder and piston unit fixed to the upwardlyextending frame members adjacent the dog which it moves with a piston rod operatively engaging the dog.

14. Apparatus as defined in claim 12 for arranging similar units into a vertical stack in which said vertically-swinging dogs and their respective cylinder and piston units are mounted on mounting members which are adjustable vertically and horizontally on their respectively vertically-extending frame members whereby the dogs may be adjusted to clear the tops of the units as they are carried by the conveyor to position over the elevator.

15. Apparatus as defined in claim 12 wherein said trip means on the frame below the elevator platform is vertically adjustable to adjust the vertical travel of the elevator relative to the height at which said dogs are positioned.

16. Apparatus as defined in claim 12 for arranging similar units into a vertical stack of predetermined height wherein there is a second vertically-movable stop means between the receiving end of the conveyor and the elevator movable betweena raised position where it obstructs the travel of a unit into position over the elevator to a lowered position clear of the travel of th units, the fluid pressure cylinder for raising and lowering the stop, a fluid pressure valve between the stop and the elevator arranged to be operated by the travel of a unit between the stop and the elevator to actuate said fluid pressure cylinder to raise the stop, and a second trip means on the frame arranged to be engaged by said means below the elevator to actuate said fluid pressure cylinder to lower the stop means as the elevator reaches its lowermost position.

17. Apparatus for arranging units into vertical stacks of predetermined height comprising:

a. a supporting frame with parallel sides and with a horizontally-extending conveyor means thereon, the conveyor means comprising two spaced parallel endless conveyors with means for continuously driving them in unison, the conveyor and frame having a receiving end onto which units to be stacked are placed and a delivery end opposite the receiving end,

b. an elevator located intermediate the said two ends and positioned between the two endless conveyors,

c. a first vertically-movable stop between the receiving end of the conveyor and the elevator for selectively controlling the movement of units by the conveyor means into position over the elevator,

d. a second vertically-movable stop means adjacent the elevator for stopping each unit as it is moved by the conveyor means over the elevator,

the frame having upwardly-extending guiding frame structures, one at each side thereof in transverse alignment with the elevator, each such upwardly-extending frame structure having a supporting plate thereon movable between a verticallyextending position where it is clear of any contact with the load at all and a horizontally-extending position where each projects under a unit which has been raised by the elevator to then be supported when the elevator descends, the plates at the two sides acting together to support the units of an incomplete stack as each unit is added,

. the elevator comprising a platform and a fluidpressure cylinder and piston below the platform for raising and lowering it, the first and second stops each having its own fluid pressure-operated cylinder and piston for raising and lowering it, each of said plates having its own fluid pressure-operated cylinder and piston unit for operating it, and

g. a first fluid pressure trip valve on the frame below the elevator and fluid pressure circuit controlled thereby arranged to be tripped by the elevator as it reaches its lower limit of travel for lowering saidfirst stop, a second fluid pressure trip valve between said first stop and the elevator and fluid pressure circuit controlled by it arranged to raise said first stop by supplying pressure to the cylinder and piston unit for that stop to effect the raising thereof when a unit moves past it toward the elevator; a third trip valve on said second stop arranged to be contacted and operated by a unit moving on said conveyor into position over the elevator and an associated fluid pressure circuit controlled thereby to effect operation of the elevator fluid pressure cylinder and piston to effect the raising of said elevator, a fourth trip valve on the frame under the elevator and associated fluid pressure circuits arranged to be operated by the upwardly-moving elevator to reverse the fluid pressure to the elevator operating cylinder and cause the elevator to lower, a fifth trip valve and associated fluid pressure circuit arranged to be operated by a stack of predetermined height for simultaneously supplying fluid pressure to the cylinders which operate the supporting plates to move them out of unit contacting position and at the same time supply fluid pressure to the cylinder and piston unit for lowering said second stop, and finally a sixth trip valve on the frame spaced toward the delivery end of the conveyor beyond the second stop and associated fluid pressure circuits for simultaneously operating the cylinder and piston units for the supporting plates in the reverse direction to restore them to unit-supporting position and at the same time effect the raising of said second stop.

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Classifications
U.S. Classification414/790.1, 414/900, 414/790.3, 414/906, 414/795.3
International ClassificationB65G57/30
Cooperative ClassificationY10S414/119, B65G57/302, Y10S414/114
European ClassificationB65G57/30B2