US2193264A - Stacking mechanism - Google Patents

Description

March 12, 1940. BASHQRE 2,193,264

STACKING MECHANISM Filed Aug. 11, 1937 5 Sheets-Sheet l /NVN7'OR QU/NTER E. BASHORE 2A RR/QKECH, P05 75 6: HARRIS A TTORNEYS.

March 12, 1940. Q. E. BASHORE STACKING MECHANISM Filed Aug. 11, 1937 3 Sheets-Sheet 2 -/N l/E N TOR O U/N TER E. 5A5 H ORE HA RR/S, K/EC/i Fos TER iHARR/s ATTORNEKS.

March 12, 1940. Q. E. BASHORE 2,193,264

STACKING MECHANISM Filed Aug. 11, 1937 3 Sheets-Sheet 5 me 45 a 0 96 l/vvs/vroR QU/NTER BASHORE Y 7g AMER/s, KIECH, F05 TER &HARR/s ATTORNEY 6.

. Pumas Mar. 12, 1940 UNITED STATES PATENT OFFICE Application August 11,

18 Claims.

My invention relates to devices for handling objects, such as boxes and trays, and is particularly directed to devices for conveying, elevating,

and stacking such objects. Since my invention a is peculiarly applicable with outstanding advantages to means specialized for stacking boxes and the like, the present disclosure will be directed primarily to a stacker, but it is to be understood that the principles of my invention may be incilisl'ggl'ated in a wide range of conveyor mecha- One object of my invention is to provide a novel form of carrier means with means associated therewith to provide for positive engagement of the carrier with a box at a receiving station.

Another object of my invention is to provide a carrier that will engage both the bottom and the sides of a box. More specifically, one oi'my objects is to provide an automatically operative box clamp that will adjust itseli. to boxes of various sizes within a substantial range oi dimensions. In this aspect of my invention it is my purpose further to provide a clamp actuated by the weight of the box engaged therewith, whereby the force of the clamping action will vary with the load being transported.

A further object of my invention is to provide means cooperative with a carrier to disengage from the carrier the lowermost box of a stack without the necessity of a pit in the floor at the stack or the necessity of mechanism on the floor to provide for such disengagement. More speciflcally, it is my object to provide for the purpose oi disengaging the bottommost box of a stacker, a means supported by the frame of the conveyor and entirely independent of the floor under the conveyor, whereby my invention may be constructed as a portable stacker. In carrying out these objects, I have the further object of providing automatic means to support temporarily at a level above the floor the first deposited box of a stack to permit disengagement oi the carrier means from said box.

A further object of my invention is to provide a novel arrangement for a conveyor chain in which the rim oi. a sprocket wheel constitutes part of the guide means for carriers mounted on the chain.

Another object of my invention is to provide a feed conveyor for a stacker that is synchronized with the stacker mechanism.

A still further object of my invention is to provide a feed conveyor i'or astacker that will fer elongated boxes or the like laterally irom a 1937, 38131 No. 158543 (UL 214-6) longitudinal conveyor to the receiving station of the stacker.

Further objects and advantages of my inventioii will be apparent in the following detailed description of a preferred form of my invention.

In the drawings, which are to be taken as illustrative only of my invention, a

Fig. 1 is a side elevation of a portable stacker constructed in accordance with the teachings of my invention 1 Fig. 2 is a rear view of the stacker shown in Fig. 3 is a duplicate of a portion of Fig. 2 showing parts in difierent positions;

Fig. 4 is a horizontal section taken as indicated by the line 44 of Fig. 1;

Fig. 5 is a face view somewhat enlarged of one of the carriers or box-engaging means incorporated in my mechanism, the carrier being in boxengaging position; 20

Fig. 6 is a side elevation of-the carrier shown in Fig. 5;

Fig. 7 is a vertical section through the carrier shown in Figs. 5 and 6, the section being taken with the carrier in retracted position; 25

Fig. 8 is a schematic view showing the electric circuit for automatic control of the stacker;

Fig. 9 is a face view of a modified form of carrier that may be employed in my stacker; and

Fig. 10 is a side elevation of the carrier shown in Fi 9.

My invention includes a substantially rectangular frame, within which is incorporated a pair of continuous conveyor chains 20 having pairs of carriers 2|, the chains and carriers being adapted to transport boxes 22 or the like from a receiving station generally designated R to a terminal or stacking station generally designated T. To provide for picking up boxes, the path of movement of the carriers 2| is upward past the receiving station R, and to provide for stacking boxes at the terminal station T, the path of approach thereto is downward. The terminal or stacking station in the arrangement to be described is simply the floor on which the stacker stands, but those skilled in the art will readily understand that the terminal or stacking station may be a truck or other transportation device.

A frame to support the conveyor chains and to accommodate mechanism for the various movements required may be constructed with four vertical corner members 24, two of the corner members on eachside of the machine being associated with one of the conveyor chains 20, and being interconnected across the frame by diagonal braces 25, an upper cross bar 28, and a lower cross bar 21.

Since it is contemplated that each corner frame member 24 will serve as guide means for one of the chains 28, the corner member may comprise a pair of spaced guide rails consisting of an inner channel-iron 28 and an outer channel-iron 28, the two channels in back-to-back disposition being interjoined at the top by a short section of channel 30 and interjoined at the bottom by a similar section of channel 3|, the joints involved being formed by welding. At the bottom of the frame, each of the corner frame members 24 may be mounted as by bolts 82 to a pedestal 33, and the two pedestals on each side of the frame interconnected by a cross member 84. In the portable type of stacker shown in Figs. 1 to 4, each of the pedestals 33 is provided with a suitable caster 35.

At each side of the frame near the top is a bearing 36 mounted on a cross member 81 interconnecting the corner members 24, in which hearing is journaled a shaft 38 carrying a large sprocket wheel 39 on each side of the frame. Each of the wheels 39 is aligned with the two corner members 24 on each side of the machine and is dimensioned to carry the conveyor chain 28 from the front corner member to the corresponding rear corner member. A feature of my invention in the preferred form is that each of the wheels 39 is substantially tangential to the inner guide rails 28 so that across the top of the frame each wheel takes the place of said inner guide rails in cooperating with an outer guide rail in the form of an arcuate channel 48 interconnecting the two outer channels 29 of the corner members 24. On each side of the machine the two channels 29 and the interconnecting channel 40 may be formed from one piece. To lend rigidity to the structure, the guide rails 48 may be interconnected by a suitable vertical yoke 42 at the top, and each guide rail 40 may be further braced by a horizontal yoke 43 at each side of the frame.

Each of the conveyor chains 28 passes upward through the forward corner frame members 24 between the guide rails 28 and 29, then moves in an arcuate path across the top of the frame between the rim of a sprocket wheel 39 and a guide rail 40, and then passes downward through a rear corner frame member 24 between the guide rails 28 and 29. Near the bottom of each of the corner frame members 24, each conveyor chain 29 makes a 90 turn around a sprocket 44 on a shaft 45 that is journaled in a bearing 45 mounted on a pedestal 33. From a sprocket 44 each conveyor chain 2|] travels forward to make a 90 turn around a second sprocket 41 carried by a stub shaft 48, the stub shaft being Journaled in a suitable bearing 49 mounted on a forward pedestal 33.

In the construction shown in. the drawings, the frame is further braced by a pair of horizontal cross members 50 interconnecting the lower cross bars 21 and a second pair of horizontal cross members 52 interconnecting the upper cross bars 28.

I prefer to incorporate in the frame means to stabilize a box in the upward movement from the receiving station R, such means being, for example, a pair of vertical angle-irons 58 supported by arms 54 extending forward from one of the upper cross members 52 and supported also by arms 55 extending forward from one of the lower cross members 50. For a purpose to be later explained, I contemplate mounting a switch. 58 on one of the angle-irons 53, the switch being provided with a switch-operating arm 51 extending forward in a position to be actuated by contact with 'boxes moving upward from the receiving station R. To lend rigidity to the assemblage, diagonal braces 58 may interconnect the two pairs of arms 54 and 55.

In like manner, to provide means for stabilizing the boxes in their downward movement at the rear of themachine, as well as to provide means to align the boxes accurately for stacking, I prefer to incorporate in my structure a pair of angle-iron guides 59 turned to receive the boxes between rearward extending guide flanges 50. The upper ends 52 of the guides 59 are bent inward to receive downwardly moving boxes, and one of the angleiron guides may be provided with a second switch 88 having an operating arm 54 disposed to be actuated by downward moving boxes. The two angle-iron guides 59 are shown mounted on short bars 85 extending rearward from the lower cross member 58 and also supported by short bars 58 extending rearward from the rear upper cross member 52, and are suitably braced by diagonal members 81.

To provide means for hanging each of the carriers 2! on conveyor chains 20, a suitable stub shaft 68 is incorporated in the chain structure as a link pin thereof, the stub shaft being provided with a retaining nut 89 at each end. In my preferred construction the stub shaft 68 carries an.

outer disc 18 and an inner disc 1i that slide respectively on the outer faces and inner faces of the guide rails 28 and 29. In the construction shown, the outer disc 18 embraces a bushing 12 and the inner disc 1| embraces a bushing 13 on the shaft.

A carrier body 14 having lateral wings 15 and, by preference, spaced vertical flanges 16, is pivotally suspended from the stub shaft 68 by means of a suitable anti-friction bearing 11. Hingedly mounted on the lower end of the carrier body 14 by means including a pin 18 and lugs 19 integral with the carrier body, is a box-engaging member 88 in the form of a plate preferably having laterally extending wings 82 and having its outer end 83 curved, as shown. The box-engaging member 88 has its axis of pivotal movement outside the path of boxes handled by the mechanism, and is adapted to move between a position clearing the boxes shown in Fig. '1 to a position to engage the:

bottom of a box, as indicated in Fig. 6.

Within the scope of my conception, any suitable means may be employed to limit the downward rotation of the box-engaging member 88 at the box-engaging position. In the preferred form of my invention shown in the drawings, the downward movement of the box-engaging member is limited by operative connection with a box-clamping means generally designated by the numeral 84, by virtue of which connection the weight of a box on the box-engaging member 80 actuates the clamping means 84 and, reciprocally, the clamping means 84 limits the movement of the box-engaging member.

The drawings indicate one manner in which such inter-relationship may be had. The clamping means 84 comprises a pair of clamp members 85 hingedly connected at their tops by a pin 86 to a plate 81 that functions as a link, the plate in turn being hingedly connected by a transverse pin 88 carried by the carrier body 14. The bottom ends of the clamp members 85 are pivotally connected by a pin 89 to a crosshead 90 that is slidingly mounted on a vertical guide rod 9|, the guide rod-extending between a boss 92 and a lug areas 93 and being secured by nuts 04 on opposite sides of the lug. The box-engaging member 00 is connected to the crosshead 00 by a pair of links 90 that are pivotally connected at their'upper ends to the pin 89 and are pivotally connected at their lower ends to a pin 90 carried by a lug 01 on the box-engaging member 00. It is apparent that, by virtue of the arrangement described, when the member moves down into box-supporting position the clamping means 04- also moves'into operative position.

In the preferred form of my invention, yielding means is provided to keep the clamp members and the box-engaging member 00 normally out of operative position, such means being shown in the drawings as a helical expansile spring 98 embracing the guide rod 0|, a nut 09 on the guide rod being provided to adjust the pressure of the spring. To provide for temporarily opening the boxengaging member" to an operative position to pick up a box, I contemplate providing means associated with the receiving station R to cooperate with the carrier, such as a pair of rollers I00 mounted on standards I02. When a carrier moves upward toward the receiving station R, the wings 15 of the carrier body contact one side of the two rollers I00, and the wings 82 of the box-engaging member 80 contact the other side, the wings 02 being moved outward by a cam action to place. the box-engaging member 80 in box-engaging position, as shown in Fig. 6. If a box is at the receiving station, as indicated at I03 in Fig. 6, the box-engaging members 80 of the two carriers 2| on opposite sides of the machine will come into supporting engagement with the bottom of the box and the weight of the box will cause the clamping means 84 to engage opposite ends of the box. 7

When a pair of carriers 2I pick up a box at the receiving station, the weight tends to rock the inner end of the stub shaft 68 downward, and the upper edge of the disc I0 and the lower edge of the disc II may, in consequence, be pressed against the faces of the guide rails 20 and 29. Asthe carriers move across the top of the frame, the two discs in the same manner will press against the guide rail 40 and the rim of the wheel 39. I have found that although there is relative movement between the wheel 39 and the guide rail 40, the two discs 12 and I3 do not tend to rotate as the carriers move in the arcuate path across'the top of the frame.

A feature of my invention is the conception that a pair of carriers of the type described may be disengaged from the first of a series of boxes to be stacked by simply providing means for temporarily supporting such box above the floor level at the terminal station, such supporting means being adapted to automatically descend to the floor level by the time the stack of boxes is completed. The automatic supporting means may be separate from the frame and rest on the floor itself, but since in some uses my device will be portable, I prefer to incorporate the temporary supporting means in the framework in a manner, for example, that will now be described.

At the rear of the frame, a platform, which may be in the form of an open frame I04, is carried by two vertical rods I05 slidingly mounted in suitable apertures in the rear cross members 50 providedwith stop pins I06. To preserve vertical alignment of the slide rods I05 a yoke I0! is mounted on the underside of the cross member 00 to likewise slidingly embrace the rod, the yoke being braced by diagonal members Illa (Fig. 1). To cushion the downward movement of the platform I 04, I provide helical expansile springs I00 embracing the rods I05 between the stop pins I06 and the cross member 00, and a second pair of similar springs I09, embracing the rods between the platform I04 and the yoke Ill, serve to cushion upward movements of the platform.

A feature of my invention is that the desired automatic action of the platform I04 may be achieved by simply providing a yielding means of suiiicient strengthto support onebox but of insufllcient strength to support a completed stack of boxes. To provide smoothness of operation, I prefer to employ an arrangement in which the force exerted by the yielding means increases at substantially less than the rate at which the platform I04 is depressed. I

In the drawings, two support springs III are connected attheir upper ends to an anchor member II2 pivoted on a rod III, the rod in turn being supported by a plate II4 carried by the diagonals 50 and a plate I I0 carried by the diagonals 61. The lower ends of the support springs III are connected to a second anchor IIO pivotally mounted on a plate I II, which plate functions, in effect, as a bell-crank. The plate III is pivotally mounted on a standard II8 extending upward from the cross member 50 and is operatively connected with the platform I04 by a connecting rod Hi, the rod engaging a pin I20 on the plate I" and a pin I2I in a lug I22 on the platform I04. The position of the supporting platform I04 and the associated mechanism, when the first box I23 of 'a'series of boxes is deposited on the platform, may be understood by reference to Fig. 3. It is apparent that when the platform is depressed to the floor level by the weight of additional boxes, as indicated by the dotted lines, the tension of the springs III will not be increased in proportion to the downward movement of the platform.

The portable box stacker of the form shown in Figs. 1 to 4 incorporates a box feeding means at the front in the form of a conveyor adapted to move boxes to the receiving station R and against the vertical members 53. Since the operation of the conveyor should be synchronized with the movements of the carriers 2| to avoid movement of boxes against the edges of the boxengaging members 80, some provision should be made in the construction of the feed conveyor to control automatically the movement of boxes into the receiving station R. A suggested construction for such a feed conveyor is shown in Figs. 1 and 4. I

The feed conveyor includes an upper rectangular frame generally designated I24 and a lower rectangular frame generally designated I25. The upper frame I24 comprises two parallel angleiron frame members I20 connected at their outer pedestals 33. The outer end of the lower frame I25 is reinforced by a pair of diagonal braces I34 extending upward from the forward pedestal members 03, and the lower frame may reinforce the upper frame I24 by virtue of a pair of short connecting members I35 extending upward from the rear cross member I30 to support the upper frame members I26.

The upper frame I24 carries a series of idler rollers I36 having trunnions journaled in upward extending flanges I31 of the angles I26, and also carries a driven roller I38 keyed to a shaft I39 journaled in bearings I40, a driven roller I42 key'ed to a shaft I43 journaled in bearings I44, and a third driven roller I45 keyed to a shaft I46 journaled in bearings I41, the bearings I40, I44 and I41 being mounted on the horizontal flanges I48 of the angle frame members I26. It is contemplated that the power driven rollers I38, I42, and I45 will be spaced to provide for continuous propulsion of a box along the extent of the feed conveyor to the receiving station R.

The means for controlling the movement of boxes to the receiving station in synchronism with the movement of the carriers 2I may be in the form of a stop arranged for cyclic operation to arrest and release boxesperiodically at some point on the feed conveyor. For example, the drawings show a pair of stops I49 on opposite sides of the conveyor positioned to engage the overhanging portions of boxes placed on the conveyor in lateral disposition for movement laterally towards the receiving station R. The stops I49 have studded engagement surfaces I50 and are pivotally mounted on standards I52 that extend upward from the forward cross members I29 of the lower frame I25. To provide for periodically raising the engagement surfaces I50 above the level of the rollers of the conveyor, I incorporate in the construction of each of the stops I49 a suitable cam member I53 positioned to be lifted periodically by a complementary roller I54, the roller being carried by a rotating arm I55 keyed to a shaft I56 that is journaled in bearings I51 on the lower frame I25.

naled in bearings I61 mounted on pairs of arms I68 at each side of the machine, as shown in Fi 4.

For the purpose of actuating the two conveyor chains 20, the countershaft I66 is operatively connected with the two stub shafts 45 at the rear of the machine that carry the rear conveyor sprockets 44, the required operative connections being provided by sprockets I69 on opposite ends of the countershaft I66 and sprocket chains I10 extending from the sprockets I69 to larger sprocket wheels I12 mounted on each of the stub shafts 45.

From a third sprocket I13, keyed to the countershaft I66,.a drive chain I14 extends forward to engage a sprocket I15 keyed to a countershaft I16, which countershaft is journaled in two bearings I11 on the lower frame members I28, and is also journaled in a third bearing I18 mounted on the previously mentioned arm I3I extending forward from the stacker frame. The shaft I 56 carrying the rollers that operate the stops I49 is driven from the countershaft I16 through. a sprocket I on the shaft I16, a sprocket chain I82, and a sprocket I83 on the'shaft I56. The

roller I88 may be driven from the shaft I56 through a sprocket I84, a chain I85, and 'a sprocket I86. A sprocket I81 on the shaft I18 drives a sprocket I88 on the shaft I46 through a sprocket chain I80, thus actuating the roller I45.

' The remaining drive roller I42 is actuated from the shaft I46 through a sprocket I92, a drive chain I93 and a sprocket I94.

The operation of my stacker will be readily understood from the foregoing description. If the stacker is of the portable type, it may be freely moved to positions of most effectiveness, for

instance, the stacker may be readily placed on a the second power-driven roller I42 which in turn tends to move the box into contact with the rear roller I45, which roller delivers the box to the receiving station R. At the receiving station the box is supported by the power-driven roller I45 and the idler roller I36.

The stops I50 periodically rise and fall to cause boxes to move into the receiving station R as fast as carriers 2| lift the boxes from the receiving station. Arriving at the receiving station R, each box is stopped by the two vertical angles 53 and brought into the desired alignment by the action of the driven roller I45 in continuing to urge the box against the vertical angles. While the box is being held at the receiving station R a pair of carriers move upward past the receiving station and are opened by the rollers I00 into box-engaging positions, whereupon the box-engaging members 80 of the two carriers take up the weight'of the box and bring the two clamping means 84 into operation against the opposite ends of the box.

The carriers move the box upward over the wheels 39 and then downward between the guide flanges .60, to the terminal station T. During these movements the carriers have inherent stability by virtue of the fact that the centers of both the carriers and the boxes are below the axes of the two stub shafts 68.

The first box to reach the yielding platform I04 is supported thereon at sufficient elevation to permit the carriers to become completely disengaged from the bottom of the first box. As subsequent boxes are piled on the first box, the platform I04 drops to the floor.

A feature of my invention is that the bent configuration of the box-engaging members 80 permits the box-engaging members to slide smoothly from between boxes when a box is deposited on another box at the receiving station. The deposited box is finally released to drop only approximately the thickness of the curved end of the box-engaging member.

The two switches 56 and 63 heretofore described represent means I prefer to incorporate in my stacker to stopthe movements of the mechanism automatically when a complete stack is formed at the terminal station T. The principles of such control may be understood by reference to Fig. 8. In the circuit for the motor I58 that is controlled by a master switch I91, I place the two heretofore mentioned switches 56 and 63 in parallel. If the stacker is constructed to form stacks of six boxes each, the switch 63 will be so positioned that the sixth or uppermost 75 encambox I98 will hold the switch lever 84 depressed, thereby holding the switch '3 open. Current will continue to be supplied to the motor I" through the switch 56, but when a box I moving upward opens the switch 56 by actuating the lever 51, as shown in Figs. 1 and 8, the motor lil will be de-energized and will remain de-energized une til the stack of boxes at the receiving station is removed to permit the switch .63 to close.

As illustrative of the fact that my carrier construction may be radically modified without departure from the principles involved, I show in Figs. 9 and 10 a simplified construction in which the clamping means as well as the particular yielding means of the carriers previously described are omitted. In this simplified carrier, a carrier body 200 may consist of a flat plate mounted on the previously described stub shaft 69 associated with one of the conveyor chains 20. A box-engaging member "I is hingedly mounted on the face of the body 200 by a suitable pin 202 extending through lugs 203 integral with the body. A short extension 204 of the boxengaging member extends below the pin 20! to limit the downward rotation of the box-engaging member by contact with the face of the carrier body 200, as may be understood by reference to Fig. 10. The box-engaging members of a pair of carriers tend to maintain their boxengaging positions throughout the closed paths ofthe carriers. Preferably, to insure such tendency I provide a leaf spring 205 to press against extension 204 of the box-engaging means. When one box is deposited on top of another box in the making of a stack, the box-engaging members 2M are moved outward by contact with the lower boxes of the stack.

My detailed description of one illustrative form of my invention will suggest to those skilled in the art a wide range of modifications and changes that do not depart from the spirit of my conception. I specifically reserve the right to all such changes and modifications that properly fall within the scope of my appended claims.

I claim as my invention:

1. In a conveyor for transportation to a terminal station in a downward path of .approach, a box-engaging means for use in stacking boxes and the like, said means comprising: a pair of members pivoted at axes spaced from. opposite sides of a proposed stack and dimensioned to a porting position to minimize the prying eifecton .weight of the box will actuate the clamping means; and yielding means to hold the clamping means open when no box is supported by said bottom-engaging means.

4. In mechanism of the class described, means for carrying boxes and the like, said means including: clamping means adapted to move from retracted disposition into engagement with opposite faces of a box and vice versa; box-engaging means movable from retracted disposition into supporting engagement with the bottom of the box, said engaging means being operatively connected with said clamping means; yielding means tending to hold both said means retracted; and means for moving said engaging means into position to engage a box.

5. In mechanism to transport boxes and the like froma receiving station to a terminal station, the combination of: clamping means adapted to engage opposite faces of a box; a box-engaging' means movable between a lower position of engagement with the bottom of a first box and an upper position to clear the box, said means being operativelyconnected with said clamping means whereby the weight of a box will actuate the clamping means; means to move said clamping means and box-engaging means from the receiving station to the terminal station; yielding means normally to hold said box-engaging means in its upper position; means associated with the receiving station to temporarily force said box-engaging means to a box-engaging position; and supporting means at the terminal station adapted to hold the first of a series of boxes at an, elevated position to release saidclamp and box-engaging means, said supporting means being adapted to descend as subsequent boxes are deposited thereon.

6. A stacker for boxes and the like adapted to form a stack at a stacking station, said stacker having in combination: a pluralityof box-engaging means adapted to support a. box from tnebottom; means for moving said engaging means successively toward said stacking station with a downward approach; and means to temporarily support the first of a series of boxes at an elevated position above the stacking station long enough to release the box from the engaging means associated therewith and thereafter to lower said first box to said stacking station, the succeeding engaging means being adapted to be released automaticallyby movement against preceding boxes of said series at said stacking station.

7. In mechanism to transport boxes and the like from a receiving station to a terminal station, the combination of: a clamping means adapted to engage opposite faces of a box; a boxenga ing means movable between a lower position of engagement with the bottom of a first box and an upper position to clear the box, said means being operatively connected with said clamping means whereby the weight of a box will actuate the clamping means; means to move said clampingand box-engaging means from the receiving station to the terminal station; and supporting means at the terminal station adapted to hold the first of a series of boxes at an elevated position to release said clamp and box-engaging means, said supporting means being adapted to descend as subsequent boxes are deposited thereon.

8. In mechanism to transport-boxes and the like from a receiving station to a stacking station, the combination of a pair of spaced carriers adapted to engage the bottom of a box at the receiving station; means to move the carriers simultaneously in paths approaching the stacking station downwardly without passing below the stacking station; and supporting means substantially wholly above the stacking station positioned in the path of the box intermediate'the paths of the carriers, said supporting means being adapted to hold a first box at an elevated position to cause disengagement of said carriers from said first box and then to drop to said stacking station when subsequent boxes are deposited on the first box.

9. In mechanism to transport boxes and the like from a receiving station to a stacking station, the combination of a pair of spaced carriers adapted to engage the bottom of a box at the receiving station; means to move the carriers simultaneously in paths approaching the stacking station downwardly; and yielding supporting means substantially wholly above the stacking station in the path of the box adapted to support a single box above the stacking station but to yield to the weight of a plurality of boxes whereby the first box deposited in the forming of a stack will pause in its downward movement at a position above the stacking station to permit disengagement from the box of said carriers.

10. In mechanism of the class described for automatically picking up boxes and the like at a receiving station and depositing same at a terminal station, the combination of: carrier means adapted to move upward in a path adjacent said receiving station and subsequently to move downwardly to said terminal station; a box-supporting member pivotally mounted on said carrier means to swing laterally between an upper position to clear said stations and a lower position to engage and support a box from below; means to limit the downward movement of said member at said lower position; yielding means urging said member toward said upper position; and means to move said member to said lower position temporarily in opposition to said yielding means as the member approaches said receiving station.

11. A mechanism of the character described for stacking boxes and the like at a terminal station, said mechanism having: conveyor means adapted to move in downward paths past opposite sides of said terminal station; a pair of members carried by said conveyor means to move simultaneously past said terminal station, each of said members being pivoted to rotate from an upper position laterally downward into the range of a bottom of a box to support the box; andmeans to limit the downward rotation of each of said members, said members being free to rotate whereby said members are rotated out of boxengaging position when moved against a box at the receiving station, said limiting means being adapted to stop said members at box-supporting positions that are upwardly inclined to minimize the prying action on the supported box when the members are rotated out of engagement therewith at the receiving station.

12. A mechanism as set forth in claim 11 in which said members are of bent configuration to further minimize said prying action.

13. A mechanism as set forth in claim 11 in which said members have curved supporting surfaces'to minimize the prying action.

14. An apparatus of the class described for successively picking up boxes and the like at a receiving station substantially above floor level and stacking the boxes at approximately floor level at a stacking station, said apparatus having: box-engagingmeans movable in a closed path upward past said receiving station and downward toward said stacking station, the closed path being wholly above floor level; and supporting means at the stacking station adapted to receive and support the first box of a stack at a position spaced substantially above floor level to free said box-engaging means from said first box before thevbox-engaging means reaches the lower limit of said closed path, said supporting means being adapted to drop to approximately floor level for a completed stack, said box-engaging means being movable out of box-engaging position by downward movement against a stacked box. I

15. An apparatus as set forth in claim 14 in which said supporting means automatically drops during the period in which a stack is being formed.

16. An apparatus as set forth in claim 14 in which yielding means holds said supporting means at the position spaced substantially above floor level, said yielding means exerting suillcient force to withstand the weight of one box but not sufficient force to withstand the weight of a completed stack whereby the supporting means will descend automatically as a stack is completed.

17. An apparatus as set forth in claim 14 in which said box-engaging means'is adapted to swing upward out of box-engaging position whereby a box at the stacking station will serve as a cam to move saidbox-engaging means out of box-engaging position.

18. An apparatus as set forth in claim 14 in which said box-engaging means is adapted to swing upward out of box-engaging position whereby a box at the stacking station will serve as a cam to move said box-engaging means out of box-engaging position, and in which yielding means urges said box-engaging means toward its upper position to prevent contact of the boxengaging means with the stacked boxes after the box-engaging means releases a box to the stack.

19. An apparatus as set forth in claim 14 in which said box-engaging means is adaptedto swing upward out of box-engaging position whereby a box at the stacking station will serve as a cam to move said box-engaging means out of box-engaging position, and in which said boxengaging means is of bent configuration to minimize the prying action thereof on a box being released by said cam action.

. QUIN'I'ER E. BASHORE.

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