US3381828A - Filled-bag stacking palletizer - Google Patents

Description

'7 Sheets-Sheet 1 Filed Feb. 7, 1966 NGE y 1968 R. T. SHEEHAN 3,381,828

FILLEDBAG STACKING PALLETIZER y 1968 R. T. SHEEHAN 3,381,828

FILLED-BAG STACKING PALLETIZER Filed Feb. '7, 1966 7 Sheets-Sheet 1 INVENTOR ROBERT T. SHEEHAN ATTORNEYS R. T. SHEEHAN May 7, 1968 FILLED-BAG STACKING PALLET [ZI'JR 7 Sheets-Sheet 4 Filed Feb.

R. T. SHEEHAN May 7, i968 FILLED-BAG STACKING PALLETIZER 3N @mm Q 01 Filed Feb.

ay 7, 1968 R. T. SHEEHAN 3,381,328

FILLED-BAG STACKING PALLETIZER Filed Feb. 7, 1966 7 Sheets-Sheet 6 FIG.I5 I

/6 ATTORNEYS R. T. SHEEHAN May 7, 1968 F BAG STACKING PALLETIZER ILLED- 7 Sheets-Sheet 7 Filed Feb. 7, 1966 ON 0E INVENTOR ROBERT T. SHEEHAN ATTORNEYS Unit ABSTRACT OF THE DISCLOSURE This automatic filled-bag-stacking palletizer automatically receives filled bags from a bag feeding conveyor coupled thereto and deposits and stacks the filled bags on a turntable in one of a number of predetermined patterns in successive tiers of three, four or five bag patterns. When the pallet has been fully loaded, a pallet dispenser then automatically pushes an empty pallet onto the turntable while causing the empty pallet to simultaneously ejected the loaded pallet onto the loaded pallet receiver. The stacking conveyor is also mounted on an elevator which raises and lowers it to different levels of stacking.

During the stacking operation, the stacking conveyor is automatically shifted relatively to the turntable both horizontally by laterally reciprocating the carriage on which the stacking conveyor is mounted and vertically by the elevator into successive parallel positions in timed relationship with the rotation of the turntable step-by-step through 90-degree intervals. The elevator is optionally provided with means for reciprocating the stacking conveyor longitudinally to extend and retract the stacking conveyor in order to stack the bags in an oblong pattern upon an oblong pallet when it is desired to use an oblong pallet.

In the accompanying drawings:

FIGURE 1 is a diagrammatic top plan view of an automatic filled-bag palletizer, according to the invention, with the hydraulic piping omitted for simplicatiOn, after having stacked bags to an odd-numbered tier of a stack of bags in a four-bag pattern;

FIGURE 2 is a top plan view of a pallet loaded to an even-numbered tier of a four-bag pattern;

FIGURES 3 and 4 are top plan views of pallets loaded with bags stacked to even-numbered tiers of three-bag and five-bag patterns, respectively;

FIGURE 5 is a vertical section, mainly in side elevation, of the feeding, stacking and turntable units, taken along the line 5-5 in FIGURE 1;

FIGURE 6 is a diagrammatic front elevation of the automatic bag palletizer shown in FIGURE 1, looking in the direction of the arrows 6-6 therein;

FIGURE 7 is a side elevation, partly broken away, of the elevating stacking conveyor carriage with the stacking conveyor shown in its lowermost position in dotted lines upon a larger scale than is shown in the central portion of FIGURE 5;

FIGURE 8 is a rear elevation of the stacking conveyor carriage shown in FIGURE 7, with the stacking conveyor shown in dotted lines;

FIGURE 9 is a side elevation of the boom conveyor, with the housing thereof removed, as shown in dotted lines in FIGURE 7, with the adjacent portions of the carriage shown in dotted lines;

FIGURE 10 is a top plan view of the stacking conveyor shown in FIGURE 9;

FIGURES l1 and 12 are rear and front ing in the direction of the arrows 11-11 and respectively in FIGURE 9;

FIGURE 13 is a top plan view of the turntable unit which carries the pallets and receives the filed bags from the stacking conveyor;

elevations look- States Patent 0 FIGURE 14 is a front elevation of the turntable units, looking in the direction of the arrows 14-14 in FIG- URE 13;

FIGURE 15 is a fragmentary side elevation f a spring-mounted yielding roller;

FIGURE 16 is a vertical section taken along the line 16-16 in FIGURE 15;

FIGURE 17 is a side elevation, partly in section, of the pallet ejector in the pallet dispenser of FIGURES 1 and 6, with the central portion omitted to conserve space and enable a showing of the parts on a large scale;

FIGURE 18 is a top plan view of the pallet ejector shown in FIGURE 17;

FIGURE 19 is a cross-section, upon an enlarged scale, taken along the line 19-19 in FIGURE 17; and

FIGURE 20 is a diagrammatic view of the hydraulic circuit for the automatic bag palletizer with the valveactuating solenoids and electric pump-driving motor.

General arrangement Briefly summarized (FIGURES 1 and 6), the automatic filled bag palletizer, generally designated 20, of the present invention includes a bag feeding conveyor 22 which receives the filled bags B from a fixed filling station 24, such as from a bag filling machine, and delivers them bag by bag to the inlet end of a stacking conveyor 26 coupled therewith. The stacking conveyor 26 conveys and flattens the filled bags and drops them one-by-one upon a turntable unit 28 which rotates in timed relationship therewith after the stacking conveyor 26 has moved stepby-step horizontally and vertically, as indicated by its dotted line positions in FIGURES 1 and 6. The bags B are deposited upon empty pallets P from a pallet dispenser 30 which also operated in timed relationship to the previously-mentioned units 26 and 28 and which at thes ame time causes the feeding of each empty pallet P to eject a loaded and stacked pallet S with its load of bags B onto a loaded pallet receiver 32, whence the loaded stacked pallets S are removed by conventional fork-lift trucks, one of which is indicated diagrammatically at T, and conveyed either to transport vehicles (not shown) or to storage places in a warehouse.

The filled bags B are also flattened while being conveyed within the stacking conveyor 26, so that as many as eight tiers of bags 13 may be accommodated on a single pallet P without toppling, and, furthermore, so that loaded stacked pallets S may in turn be stacked one upon another within the warehouse, thereby conserving storage space and reducing the cost of storage. In the warehouse, as many as four loaded stacked six-tier pallets can be placed on top of one another up to an overall height of 16 feet by a suificiently high loading fork lift truck. The hydraulic pressure fluid by which the various units are actuated is supplied from a hydraulic power unit, generally designated 34. In the central portion of FIGURE 1, the order of stacking of the bags B is indicated by their numbers B-l, 3-2, 13-3 and 13-4. It will be observed from FIGURES l to 4 inclusive that the bags B are stacked in diiferent sequences in even-numbered and odd-numbered tiers so that the bags of one tier overlap the junctions of bags of adjacent tiers in order to prevent slippage and consequent toppling.

Bag-feeding conveyor The bag-feeding conveyor 22 (FIGURE 5) is movably mounted upon a platform which in turn is mounted on the floor 42 of the building in which the stacking and palletizing operations are taking place. The bag-feeding conveyor 22 includes a step-ladder-shaped A frame 44 on the bottom of which are mounted swivel casters 46 and on the top of which a lower pivot bearing 48 is mounted. The latter through a pivot shaft 50 cooperates with an upper pivot bearing 52 mounted on the bottom of the upper end of the feeding conveyor housing 54. Mounted upon and journaled in the housing 54 at opposite lower corners thereof are idler and drive pulleys 56 and 58 respectively carrying a conveyor belt 60 of flexible material, such as rubber. The upper and lower courses of the conveyor belt 60 are supported by idler rollers 62 and 64 respectively. The drive pulley 58 is driven by a belt 66 from a motive pulley 68 driven by a rotary hydraulic motor 70. Pivoted at 69 to the opposite side Walls of the housing 54 are swinging bag guide plates 71 connected to adjustment rods 73 slidable in spacedly-drilled guide sleeve 75 welded to the side walls of the housing 54 and adapted to receive angle-locking pins 77. Secured as by welding to and depending from the housing 54 at its lower forward corner beneath the drive pulley 58 is an upper pivot bracket 72 which is drilled centrally to receive a pivot pin 74.

Palletizing stacking conveyor The pivot pin 74 extends downwardly through one of a series of longitudinally-spaced holes 80 in a bearing plate 81 mounted on a lower pivot bracket 82 projecting rearwardly from the lower rearward corner of the supporting frame 84 (FIGURES 9 and of a bag-depositing boom conveyor, generally designated 86, forming a part of the stacking conveyor 26. As previously stated, the boom conveyor 86 is raised and lowered in order to perform its function of depositing the filled bags B upon the turntable unit 28, and, for rectangular or Oblong pallets, also reciprocates longitudinally, as in stacking bags in the five-bag pattern of FIGURE 4. As a consequence, as explained more fully below in the descritpion of the operation of the invention, the frame 44 of the bagfeeding conveyor 22 is moved back and forth as well as rotated through a partial revolution in response to the motions of the boom conveyor 86. The latter also tilts the housing 54 around the pivot shaft 50 as it rises and falls, thereby maintaining the lower forward end of the feeding conveyor 22 constantly in close proximity to the rearward end of the boom conveyor 86. The supporting frame 84 includes parallel longitudinal inverted T-members 87 composed of angle bars secured back to back and upon which it rests (FIGURE 11).

Deferring for the moment the detailed description of the boom conveyor 86, it will be observed from FIG- URES 5, 7 and 8 that the boom conveyor 86 is supported and moved upward and downward as well as forward and rearward upon a tower-like carriage 88 which in turn is mounted for lateral hor' ontal travel up n parallel channel V-tracks 90 mounted on and secured to the floor 42. For this purpose, the bottom of the frame 92 carries grooved wheels 94 which ride on and move laterally along the tracks 90. The tracks 90 are interconnected at their opposite ends and intermediately by cross members 96. The cross members 96 at their midpoints are interconnected by a channel member 98 (FIG URE 7).

Mounted on the channel member 98 is a cylinder 100 of a reciprocatory hydraulic carriage motor 102 containing the piston head (not shown) of a piston 104. The piston 104 carries a clevis 106 pivoted at 108 to a depending bracket 110 which in turn is secured to the under side of the bottom of the frame 92 of the carriage 88. As a consequence, admission of pressure fluid alternately to one end of the cylinder 100 and its release from the opposite end causes the piston 104 and consequently the carriage 88 to move back and forth laterally relatively to the tracks 90. Secured to the tracks 90 (FIGURE 7) are upstanding brackets 112 carrying holddown rollers 114 engaging holddown roller tracks 116 secured to the base of the frame 92 (FIGURE 8). These holddown rollers 114, as their name indicates, hold down the carriage 88 and prevent it from jumping its tracks 90 as it moves to and fro along them.

The frame 92 of the carriage 88 includes four inwardly-facing vertical channel guide posts 116 (FIG- URES 7 and 8), opposite pairs being interconnected by longitudinal cross members 118. Bolted to the right-hand pair of cross members 118, looking from the rear in FIGURE 7, is the cylinder 120 of a vertical reciprocatory hydraulic lift motor 122, the piston 124 of which (FIGURE 7) is pivoted at 126 to a cross bar 128, the opposite ends of which are welded or otherwise secured to vertical channel slides 129 which are slidable in the right-hand pair of channel guide posts 116. Midway between the left-hand pair of posts 116 there is mounted the cylinder 130 of a vertical reciprocatory hydraulic motor 132, the lower end of which is pivotally mounted at 134 on the frame 92. The hydraulic motor 132 is, except for this pivotal self-aligning mounting of the lower end of its cylinder 130, otherwise of the same construc tion and has the same connections as the hydraulic motor 122, and its piston (not shown) corresponding to the piston 124, is similarly pivoted to a cross bar (not shown) similar to the cross bar 128, similarly secured to vertical channel slides like the slides 129 but which are Slidable in the left-hand pair of channel guide posts 116.

Each of the cross bars 128 carries two pairs of spaced depending ears 136 between each of which is rotatably mounted a sprocket 138. Trained over each sprocket 138 is a sprocket chain 140, the outer end of which is anchored to one of the uppermost cross members 118. The opposite ends of the sprocket chains 140 are anchored to a vertically-movable elevator frame 142 (FIGURE 8) which is likewise guided for vertical motion between the vertical channel posts 116. As a consequence, when hydraulic pressure fluid is admitted to the lower ends of the cylinders 122 and 132, and discharged from the upper ends thereof, the pistons 124, cross bars 128 and sprockets 138 are pushed upward, thereby pulling the sprockets chains 140 upward and moving the elevator frame 142 upward, guided by the channel slides 129 within the channel posts 116. By this arrangement, the elevator frame 142 is made to rise higher than the posts 116, and twice the length of stroke of the pistons 124.

Boom conveyor Longitudinally slidably mounted upon the elevator frame 142 for forward and rearward motion relatively thereto are the inverted T-members 87 of the supporting frame 84 of the bag-depositing boom conveyor 86, which has an enclosing housing 144 composed of top, bottom and side plates (FIGURE 5). Such motion is brought about by a horizontal reciprocatory hydraulic boom conveyor motor 146 (FIGURES 9 and 10'), the rearward end of the cylinder of which is pivotally mounted at 148 on the elevator frame 142, whereas the forward end of the piston thereof is pivotally connected at 150 to the bottom of the boom conveyor housing 144. By supplying hydraulic pressure fluid to one end of the hydraulic motor 146 and discharging it from the other end, the boom conveyor 86 may be caused to move longitudinally forward and rearward relatively to the elevator frame 142. This longitudinal motion, however, is ordinarily inactive when the machine 20 is stacking bags B in a square pattern upon a square pallet, as in FIGURES 1 to 3 inclusive, and is brought into play when stacking an oblong pattern of bags upon an oblong pallet, such as the five-bag pattern shown in FIGURE 4.

The support frame 84 of the boom conveyor 86 consists of an elongated open-centered ca ge-like framework of steel angle members and channel members, including the parallel inverted T members 87, and has a longitudinallyelongated opening 152 in the forward lower end thereof (FIGURE 9) for the ejection of the bags B upon the pallet P. Also mounted forwardly and rearwardly of the opening 152 are two laterally-extending longitudinallyspaced facing channel guide members 154 which slidably support the bag release gates described below.

Rotatably mounted on the rearward end of the boom conveyor supporting frame 84 is a lower conveyor belt drive shaft 156 carrying a lower conveyor belt drive pulley 157 and a rearward driving drum 158 over which is trained a lower endless conveyor belt 160. The latter at its forward end is trained around an idler drum 162 which is rotatably mounted on the shaft 164 adjustably secured to the framework 84 for belt-tightening purposes. Intermediately, the upper course of the lower conveyor belt is supported by longitudinally-spaced parallel upper rollers 166, the lower course being supported by similar rollers 168 arranged in staggered relationship to the upper rollers 166 (FIGURE 9).

Rotatably mounted on top of the boom conveyor supporting frame 84 is an upper conveyor driving drum 170 on a shaft 172 carrying an upper conveyor belt drive sprocket 774 (FIGURE 9). Also rotatably mounted on the top of the frame 84 is an idler sprocket 176. Trained around the drive sprockets 157 and 174 and the idler sprocket 176 and also around a power output sprocket 178 is a sprocket chain 180. The power output sprocket 178 is keyed or otherwise drivingly secured to the output shaft 180 of a speed reducer 182 which, as shown in FIGURE 9, is driven by a rotary hydraulic motor 134 through a v V-belt 185 (FIGURE 11).

Rotatably mounted near the forward end of the boom conveyor supporting frame 84 is an idler drum 188 (FIG- URE 9), and between it and the conveyor driving drum 170 are rotatably mounted thrust rollers 190 disposed on longitudinally-spaced parallel axes of rotation. Trained around the drums 170 and 188 and beneath the thrust rollers 190 is an upper endless conveyor belt 192 spaced vertically away from the lower conveyor belt 160' so as to provide a bag passageway 194 therebetween.

Also mounted on top of the boom conveyor supporting frame 84 is an inverted U-shaped auxiliary frame 196 within which is mounted a vertically-movable slide 198. Rotatably mounted on the lower end of the slide 198 is a belt flattening roller or drum 2011. The slide 198 is moved upward or downward vertically in its auxiliary frame 196 by screw shafts 2112 threadedly engaging the top of the auxiliary frame 196 and carrying hand cranks 204.

Mounted in longitudinally-spaced parallel relationship on the opposite sides of the boom conveyor supporting frame 84 are bushings 206 (FIGURES l0 and 11). Slidably mounted within the bushings 206 are stub shafts 208, the inner ends of which, within the housing 144, are connected to flexible elongated narrow bag guide plates 210. The rearward ends of the guide plates 210 r are flared outwardly at 212 to facilitate entry of the bag. Consequently, by moving the shafts 2118 inward or outward within their respective bushings 2116, the bag guide plates 210 may be brought closer together or moved farther apart in accordance with the size of the bags being stacked at that particular time. The bushings 206 are provided with holes 214 to receive angle pins 216, the shanks of which pass downward through aligned holes in the shafts 208 for locking the latter in their adjusted positions.

Mounted on top of the forward end of the boom con veyor frame 84 (FIGURE 10) is a reciprocatory gateoperating hydraulic motor or cylinder 218, the piston 220 of which carries a cross head 222 to which are self-aligningly pivoted the inner ends of links 224, the outer ends of which are self-aligningly pivoted to the ends of yokes 226 loosely and rotatably mounted on parallel shafts 228, the outer ends of which are connected to the upper ends of bent or bellcrank levers 230 pivotally mounted on brackets 232 welded or otherwise secured to the top of the boom conveyor frame 84.

Pivotally connected to the lower ends of the bent levers 230 are brackets 234 which are welded or otherwise fixedly secured to the outer ends of oppositely-moving gates 236. Rotatably mounted on the inner corners of the gates 236 are rollers 238 (FIGURES 9 and 12) which roll back and forth in the channel guide members 154 as the gates 236 are opened and closed by the swinging of the bent levers 230 in response to the reciprocation of the piston 220 and cross head 222 of the hydraulic motor or cylinder 218. The upper brackets 232 and lower brackets 234 are interconnected by shafts 240 and 242 respectively which the bent levers 231 pivotally engage (FIGURE 9). Sufiicient clearances are provided between the outer portions of the gates 236 and the boom conveyor frame 84 to permit such outer portions to rise without interference as they are pulled outward and upward by the lower arms of the bent levers 230. Pivotally mounted as at 244 on the upper outer end of the boom conveyor frame 84 (FIGURE 9) is a swinging depending plate 246 which operates a limit switch 248 mounted on the end of the frame 84 when a bag B of the conveyed and stacked material collides with the swinging plate 246 before being dumped by the opening of the gates 236 in response to the action of the limit switch 248.

Pallet-receiving turntable unit The turntable unit 28 (FIGURES 12 to 15 inclusive) is mounted in front of the boom conveyor 86 and below the opening 152 therein. It consists of a supporting base 250- which in turn is bolted or otherwise secured to the floor 42 (FIGURE 13). The supporting base 250 is preferably of hollow steel construction. Mounted at 90-degree inter vals around the top of the base 256 are wheel forks 252 rotatably supporting the axles 254 of wheels 256. Also rotatably supported within the base 250 is a rotary vertical shaft 258 placed at the center of a hollow inverted cupshaped turntable 260 having a circular top wall 261 and a depending cylindrical side wall 263. The shaft 258 is seated in a socket 262 in a block 264 bolted or otherwise secured to the under side of the top wall 261 of the turntable 260. Secured to and rising from the top of the turntable 260 are two pairs of elongated parallel plates, namely a pair of outer plates 266 and a pair of inner plates 268, the latter having flared outer ends 270. The outer and inner parallel plates 266 and 268 are drilled at closely-spaced intervals to receive the axles of multiple rollers 272 arranged in two sets spaced apart from one another by the inner plates 268.

Mounted at one end of the pathway plates 273 between the inner plates 268 is a spring-loaded roller unit 274 (FIGURES 13, 14 and 15) arranged to project slightly above the level of the tops of the rollers 272. The roller unit 274 consists of a roller 276 loosely and rotatably mounted upon a shaft 278, to the opposite ends of which are bolted angle plates 28% movable up and down in cupshaped retainers 282 and urged upward by helical compression springs 284. A slotted guide plate 286 is mounted on the opposite side of the spring 284 from the retainer 282. As a consequence of this construction, the roller 276 is urged upward to a level limited by the top wall of the retainers 272 and is yieldable when subjected to a heavy weight, such as a loaded pallet. Mounted on the top wall 261 of the turntable 260' outwardly from the springloaded roller 274 is a helper roller 288 rotatably supported by brackets 290.

The turntable 260 is rotated by a turntable driving unit, generally designated 292 (FIGURE 1). The turntable driving unit 292 is mounted upon a base 294 secured to the floor 42 adjacent the periphery of the turntable 260 and includes a drive Wheel 296 mounted on a shaft 298 journaled in a vertical housing 299 in the base 294 and having a sprocket 360 keyed thereto. The sprocket 300 is driven by a sprocket chain 302 from a sprocket 304 mounted on the output shaft 396 of a speed reducer 308, the input shaft 310 of which is coupled to the motor shaft 312 of a rotary hydraulic motor 314.

Empty pallet dispenser Stacked empty pallets P are fed to the turntable 260 of the turntable unit 28 by the pallet dispenser 30 located beside it (FIGURES 1, 6, 17 and 18). The pallet dispenser 30 includes a base framework 320 including a bed frame portion 322 and elevated roller supporting frames 324 spaced above the bed frame portion 322 on opposite sides thereof. Mounted with their axes of rotation in longitudinally-spaced relationship on the elevated frame portion 324 are two sets of parallel rollers 326 which are freely rotatable. The pallet dispenser 30 also has a front wall 328 facing the turntable unit 28 and having, adjacent the level of the rollers 326, a horizontally-elongated opening 330 slightly greater than the width and height of a pallet P so as to enable a single pallet P to be ejected through the opening 330 while the front wall 328 above the opening 330 restrains the pallets in the remainder of the stack of pallets above the pallet being ejected.

Also rising from the base framework 320 is a rear wall 332, and extending between the front wall 328 and rear wall 332 is an adjustable side wall 334. The latter is movable toward and away from the sets of rollers 326 in order to adjust the pallet dispenser 30 to accommodate different sizes and shapes of pallets. The forward and rearward walls 328 and 332 and the side walls 334 are provided with slanting braces 336, 338 and 340 respectively, the latter being secured at the lower rearward ends to bottom members 342. The rear wall 334, with its braces 340 and bottom members 342, may be slid backward and forward along the base frame 320 and bolted into its adjusted position in suitable located bolt holes (not shown) in the base frame 320.

Mounted on the bed frame portion 322 of the base frame 320 by means of cross channel members 344 (FIG- URE 17) by brackets 346, and between inwardly-facing longitudinal side members 347 is a reciprocatory doubleacting hydraulic pallet motor 348 forming the motive portion of a pallet ejector, generally designated 350. Reciprocably mounted in the cylinder 352 of the hydraulic motor 348 is the head (not shown) of a piston 354. Mounted on the threaded forward end of the piston 354 is a T-shaped cross head 356 (FIGURES 18 and 19), the longitudinal portion of which is drilled horizontally to receive a pivot shaft 358 upon which sprockets 360 are rotatably mounted on opposite sides of the cross head 356 for travel back and forth therewith. Mounted on the forward end of the cross head 356 is a transverse channel bar 362, to the middle of which is secured an angle bracket 364 rotatably supporting a roller 366 at the level of the pathway plate 273 so as to roll therealong when the piston 354 and cross head 356 move outward on their forward stroke, as explained below in the description of the operation of the invention.

Bolted or otherwise secured to the opposite ends of the transverse channel bar 362 are two elongated longitudinally-extending channel draw bars 368 (FIGURE 18) arranged in laterally-spaced parallel relationship on opposite sides of the hydraulic motor 250. Rotatably mounted at intervals along the side members 347 by brackets 370 secured thereto are horizontal guide rollers 372 rotatably on vertical axes and adapted to engage the outer sides of the draw bars 368 through openings 374 in the side members 347. The channel draw bars 368 are supported for longitudinal reciprocation upon longitudinallyspaced pairs of rollers 376 (FIGURE 19) mounted at intervals on horizontal axles 378 supported by the side members 347 on the inner faces thereof.

Mounted for longitudinal travel along and relatively to the channel draw bars 368 (FIGURE 19) is a pallet ejector carriage, generally designated 380, which is provided at the four corners of its base with wheels 382 rotatable on horizontal axes and rolling along the inner sides of the channel draw bars 368. The carriage 380 in the upper portion of its frame 384 is provided with a horizontal pivot shaft 386 upon which are pivoted laterallyspaced ears 388 welded or otherwise secured to the forward face of a swinging pallet pusher plate 390. The pallet pusher plate 390 during the forward stroke of the carriage 380 remains in an upright position against a back stop 392 on the carriage frame 384. On the rearward stroke of the carriage 380, the pusher plate 390 swings downward and forward to pass beneath the stack of empty pallets and springs upward when it passes beyond the lowermost pallet, as explained below.

Anchored as at 394 near the forward upper corners of the carriage frame 384 are two parallel forward sprocket chains 396 which pass over and around the sprockets 360 on the cross head 356 to fixed anchorages 398 (FIGURE 17) on the forward channel member 344. From a fixed anchorage 400 on the same forward channel member 344, a pair of parallel rearward sprocket chains 402 extend rearwardly around sprockets 404 rotatably mounted on the inner sides of the channel draw bars 368. The rearward ends of the rearward chains 402 are secured to rearward anchorages 406 on the rearward ends of the carriage frame 384 (FIGURE 17). Mounted on the side members 347 beneath the sprockets 404 are rollers 408. As a consequence, when hydraulic pressure fluid is supplied to the rearward end of the hydraulic cylinder 352 and exhausted from the forward end thereof through suitable ports (not shown), the piston 354 moves forward, carrying with it the cross head 356 and its sprockets 360 which thereby roll along and pull forward the forward sprocket chain 396, causing the carriage wheels 382 to roll along the channel draw bars 368 While the draw bars 368 themselves are being pulled forward through their connections to the forward end of the cross head 356. In so doing, the pusher plate 390 pushes a pallet onto the turntable 260. At the same time, the rearward sprocket chains 402 travel around the sprockets 404 as the carriage 380 moves forward relatively to the channel draw bars 368 as these in turn move forward relatively to the side members 347. When the hydraulic fluid to the cylinder 352 is reversed, the opposite or retraction motion of the carriage 380 is effected, and the pallet pusher plate swings downward while passing beneath the stack of pallets. Meanwhile, the roller 366 travels along the turntable pathway plate 273 (FIGURE 17) during both the forward and return strokes of the piston 354 of the hydraulic motor 348. By this arrangement, the pusher plate 390 is caused to travel twice the length of stroke of the piston 354.

Loaded pallet receiver The loaded pallet receiver 32 (FIGURES l and 6) is in the form of an elevated roller platform 410 formed of channel members supported on a framework 412, and carrying elongated closely-spaced parallel rollers 414. As explained below in connection with the operation of the invention, the ejection of an empty pallet P from the pallet dispenser 30 simultaneously pushes a loaded pallet from the turntable 260 onto the roller platform 410, where it is picked up by a conventional fork lift truck T (FIG- URE 1) and by it conveyed to a transported vehicle, such. as a freight car, trailer or truck, or to a storage position, as in a warehouse. If there is a loaded pallet already on the roller platform 410, it is pushed therealong by the arriving loaded pallet which in turn is being pushed by the empty pallet being dispensed from the pallet dispenser 30.

Hydraulic system The various motions of the automatic bag palletizer 20 are brought about by a hydraulic system, generally designated 420, shown in FIGURE 20, and supplied with hydraulic pressure fiuid from the hydraulic power unit 34 shown diagrammatically in FIGURE 1. The hydraulic power unit 34 includes a hydraulic fluid tank 422 from which a suction line 424 proceeds through a strainer 426 to the intake of a constant delivery rotary hydraulic pump 428 driven by an electric motor 430 through a coupling 431. The outlet of the hydraulic pump 428 discharges hydraulic pressure fluid into a pressure-fluid supply line 432 for the remainder of the hydraulic circuit 420 and a hydraulic fluid return line 434 carries hydraulic fluid from the remainder of the hydraulic circuit 420 back to the tank 422 by way of a filter 435. The pressure fluid supply line 432 runs to the inlet ports of eight conventional solenoidally-operated four- way control valves 436, 438,

440, 442, 444, 446, 448 and 450, all of which are operated in both directions by solenoids and centered by springs to neutral or no-delivery positions except the valve 444 which in one direction is spring-operated. These four-way valves are conventional, available on the open market and their details are beyond the scope of the present invention. In the apparatus as actually constructed, the lines 432 and 434 are connected to manifolds, which have been omitted to simplify the disclosure.

From the boom lift control valve 440, service lines 452 and 454, including flexible hoses, run to opposite ends of the reciprocating boom lift motors or cylinders 122 and 132 by way of conventional flow control valves 456 including check valve and throttle valves for speed regulation. Also included in the lines 452 are pilot check valves 458 which automatically close to prevent sagging of the boom when the valve 440 is shifted to its neutral position, but which are Opened forcibly by pressure fluid through lines 460 connected to the line 454 during the retraction strokes of the cylinders 122 and 132 in lowering the boom conveyor 86. From the boom extension cylinder control valve 442, service lines 462 and 464, including flexible hoses, run to opposite ends of the horizontal reciprocatory hydraulic boom motor or cylinder 146. The line 464 contains a conventional needle valve 466 for piston speed regulation. From the boom gate cylinder control valve 444, service lines 468 and 470 run to opposite ends of the reciprocatory hydraulic gate-operating motor or cylinder 218, the lines 468 and 470 containing flow control valves 472 similar to the flow control valves 456.

From the pallet dispenser cylinder control valve 446, service lines 474 and 476 run to opposite ends of the reciprocatory hydraulic pallet dispensing motor or cylinder 348, these lines containing flow control valves 478 identical with the flow control valves 456. From the boom carriage cylinder control valve 448, service lines 480 and 482 run to the opposite ends of the reciprocatory hydraulic carriage motor or cylinder 102, these lines also containing flow control valves 484 identical with the flow control valves 456. From the turntable motor control valve 450, service lines 486 and 488 run to the hydraulic fluid supply and exhaust ports of the rotary hydraulic turntable motor 284. The line 436 contain a conventional needle valve 490 for motor speed regulation, whereas the line 483 contains a conventional decleration valve 492 including a check valve 494 and a restriction valve 496 operatively connected to a conventional slow-down governor 498 for retarding the motion of the turntable 260 as it nears each of its stopping points.

From the feeding conveyor motor control valve 436,

service lines 560 and 502 run to the hydraulic fluid supply and exhaust ports of the rotary hydraulic bag-feeding conveyor belt motor 70, the line 502 containing a conventional needle valve 504 for motor speed regulation. Similarly, from the boom conveyor motor control valve 438, service lines 506 and 508 run to the hydraulic fluid supply and exhaust ports of the rotary hydraulic boom conveyor belt motor 182, the line 508 containing a conventional needle valve 510 for motor speed regulation. In order to indicate the pressure in the pressure fluid supply line 432, a branch line 512 leads from the line 432 to a conventional pressure gauge 514 by way of a conventional gauge isolator 516.

Since the hydraulic circuit of FIGURE 20 shows that the various control valves are operated by solenoids, it will be evident that the energization of these solenoids to shift the various valve members, such as piston valve members, in one direction or the other, requires an electric circuit. In the automatic bag palletizer 20 as actually constructed, such an electric circuit has been provided, with the energization of the various solenoids controlled by limit switches and, in the actual stacking operation of each tier of bags, by a stepping switch or relay which closes a circuit to shift the boom conveyor 86 to the next higher level when a tier of bags has been laid, in cooperation with the location of the turntable unit 28. The same circuit contains a limit switch which shuts down the apparatus when the supply of empty pallets in the pallet dispenser 30 becomes depleted to the point where there would be no pallet available for ejection on the turntable unit 28 to receive the bags dropping from the boom conveyor 86. Furthermore, for the stacking of bags upon an oblong pallet, as in the five-bag pattern of FIGURE 4, additional switches come into operation for actuating the control valve 442 which controls the actuation of the boom cylinder or reciprocatory motor 146.

The electrical circuit referred to above for actuating the various elements of the hydraulic circuit 420 of FIG- URE 20 is unavoidably complicated and, in order to simplify the disclosure, has been omitted. It will be evident that the various switches for controlling the various control valves 440 to 450 could be actuated in timed relationship, For the purpose of simplifying the explanation of the operation of the invention, such manual switch operation, in cooperation with the automatic closing and opening of the limit switches mentioned above, will be assumed.

Operation In the operation of the invention, let it be assumed that a supply of empty pallets P has been piled in a stack upon the rollers 326 of the elevated frames 324 (FIG- URES 1 and 6) and that a four-bag pattern of bags B is to be stacked. The operator starts the electric motor 430 to place the hydraulic pump 428 in operation (FIGURE 20) so as to supply hydraulic pressure fluid, such as hydraulic oil under pressure, to the pressure fluid supply line 432 and thence to the various control valves 438 to 450. When their respective control valves 436 and 438 are suitably shifted, pressure fluid is supplied to the hydraulic motors 70 and 182 of the feeding conveyor 22 and stacking conveyor 26 respectively. Let it further be assumed that the solenoid control valve 448 has been momentarily energized to cause the carriage motor or cylinder 102 to shift the carriage 88 laterally so as to position the boom conveyor opening 152 directly over the pallet P on the turntable 260.

Bags B to be stacked are then fed one by one to the outer end of the feeding conveyor 22, the endless conveyor belt 60 of which carries the bags B downward and at its inner end deposits them upon the lower endless conveyor belt 16%) of the boom conveyor 86 of the stacking conveyor 26. The motion of the upper course of the conveyor belt carries each bag B beneath the upper con veyor belt 192, the lower course of which converges toward the upper course of the lower belt 160. As each bag passes into the decreasing space between these conveyor belts, as regulated by the adjustment of the pressure roller 200 (FIGURE 12), it is subjected to a flattening action by the compression exerted upon it by the two belts. This flattening action is of importance because it enables many more tiers of bags to be stacked one on top of the other without lateral sliding than with ordinary bags which slide because of their naturally rounded shape when not subjected to such flattening action.

The bags, thus flattened, are carried forward to a position above the opening 152 (FIGURE 9) where each bag encounters the swinging plate 246 (FIGURE 9) which shifts the limit switch 248. This in turn energizes the solenoid of the control valve 444 which immediately actuates the hydraulic reciprocatory gate motor or cylinder 218 to slide open the gates 236. The bag then drops through the opening 152 onto a pallet P on the turntable 260 (FIGURE 1), at the same time releasing the limit switch which immediately tie-energizes the solenoid of the gate control valve 444, the spring of which at once shifts the valve member to its reversed position and causesthe gate motor or cylinder 218 to close the gates 236. The gates 236, however, are maintained in an open position by a timer (not shown) to delay the closing thereof until the bag B has been deposited upon the pallet P on the turntable 260, The same action halts the feeder conveyor motor 70 to prevent piling up of bags within the boom conveyor 86 and also to initiate and permit the turntable control valve 450 to be energized long enough to cause the rotary hydraulic motor 284 to rotate the turntable 260 clockwise through a 90-degree angle or quarter revolution. As the turntable 260 nears its halting point, its speed is retarded by the slowdown governor 498 to cause deceleration and thereby prevent the bag or bags B already on the pallet from being shifted by reason of their momentum.

As soon as the turntable 250 of the turntable unit 28 has rotated through this quarter revolution, the solenoid of the turntable motor control valve 450 is de-energized, causing the valve 450 to shift to its neutral position, halting the turntable 260. The timer then energizes the feeding conveyor motor 70 to feed another bag B into the boom conveyor 86, where, as before, it is flattened, conveyed to a position over the gates 236 above the opening 152, and the limit switch operated by the newly-arriving bag to again open the gates and deposit the second bag upon the pallet in the second position at right angles to the first bag (FIGURE 1). The timer just mentioned also delays the operation of the feeding conveyor 22 and stacking conveyor 26 until the turntable has been able to rotate 90 degrees at a time to each of its indexed positions. At the same time, the dropping of each bag actuates a stepping switch (not shown) which counts off the number of bags deposited upon the pallet P in each tier.

The action of the feeding conveyor 22, stacking conveyor 26 and turntable unit 28 continues in the abovedescribed manner until four bags have been deposited upon the pallet P of the turntable unit 28, whereupon the stepping switch energizes the control valve 448 of the boom conveyor carriage motor or cylinder 102 and also the control valve 440 of the lift motors or cylinders 122 and 132, thereby causing the carriage motor 102 to move the carriage 88 laterally along its tracks 90 and at the same time move the elevator frame 142 and boom conveyor 86 upward to the next bag tier level shown in dotted lines at 86 in FIGURES 1 and 6. The foregoing cycle of operations then repeats itself, again depositing four bags in succession, one after another, to form a second tier, but with the bags B of the second tier overlapping the bags B of the first tier, as shown by the contrasting positions of the bags in FIGURES 1 and 2. This overlapping of the bags in effect ties the successive tiers of bags together by their weight and frictional engagement, thereby preventing sliding relatively to one another while the flattening action to which they are subjected in passing through the 'boom conveyor 86 also increases the area of contact between the bags and further aids in preventing slippage.

The turntable 260 of the turntable unit 28 moves through a quarter revolution after the deposit of each bag, and the boom conveyor 86 of the stacking conveyor 26 moves laterally and upward at the completion of stacking of each tier of bags B, thus oscillating between the solid line and dotted line positions of the boom conveyor 86 shown in FIGURES 1 and 6, but continuing upward on successively heightened levels.

As the boom conveyor 86 rises from tier to tier, it trips a dog at each tier which actuates a stepping switch (not shown). The latter halts the action of the boom conveyor 86 of the stacking conveyor 26 when the prescribed number of tiers of bags B has been laid. Meanwhile, as the carriage 88 shifts back an forth and the boom conveyor 86 rises, the outlet of the feeding conveyor 22 follows the motions of the inlet of the boom conveyor 86 through the pivotal connection 74 between it and the boom conveyor 86 and by the swinging of its tower frame 44 upon the platform 40 upon its caster wheels 46.

When the boom conveyor 86 has laid the uppermost tier of the prescribed number of tiers upon the pal-let P on the turntable 260, the electrical circuit energizes the solenoid of the pallet ejector control valve 446 to admit pressure fluid through the line 474 (FIGURE 20), to the rearward end of the pallet motor or cylinder 348 while discharging fluid through the line 476 from the forward end thereof. This action causes the piston 354, cross head 356, rotor 366 and pallet ejector carriage 380 to move forward (FIGURES 6 and 17), pushing an empty pallet P off the bottom of the stack of pallets forwardly over the turntable 260. At the same time, the empty pallet P pushes the loaded pallet L off the turntable 260 onto the receiving platform 32 (FIGURE 6) whence it is removed by a fork lift truck T and conveyed to its place of disposal, such as to a transport vehicle.

As the empty pallet P reaches its proper position upon the turntable 260, the ejector carriage 380 actuates a limit switch (not shown) which reverses the energization of the pallet motor control valve 446 and causes the retraction of the piston 354 and carriage 380. As the pivoted pallet ejector plate 390 swings beneath the stack of empty pellets in the pallet dispenser 30, it swings downward around its pivot shaft in a clockwise direction (FIGURE 17) until it passes beyond the rearward edge of the lowermost pallet P, whereupon it swings upward against the stop member 392 into its vertical position, ready to eject the next pallet P off the bottom of the stack onto the turntable 260 in the manner described above, when called for at the completion of stacking the prescribed number of tiers of bags B upon the previously ejected pallet P on the turntable 260.

At the conclusion of the ejection of the loaded pallet P by the next succeeding empty pallet P, the electric circuit energizes the stacking conveyor carriage motor control valve 448 and boom conveyor control valve 440 to reverse them, causing the carriage 88 to return laterally and the boom conveyor 86 to descend to their respective starting positions by the reverse action of the carriage motor 102 and the lift motors 122 and 132. The cycle of operations then repeats itself in the manner described above until the prescribed number of tiers of bags have been deposited upon the pallet P on the turntable 260 and ejection again occurs by the advancing of a new empty pallet P onto the turntable 260, as described above.

To stack a three-bag pattern (FIGURE 3), a slightly oblong pallet P is required instead of the square pallet P employed for stacking the four-bag pattern described above and shown in FIGURES l, 2, 5 and 6, which did not require the operation of the boom motor control valve 442 and boom motor 146. In the stacking of a three-bag pattern, therefore, the boom cylinder control valve 442 is energized to operate the boom motor 146 so as to extend the boom conveyor 86 longitudinally during the stacking of each tier of three bags B in order to compensate for the elongation of the pallet and bag pattern.

The stacking of a five-bag pattern (FIGURE 4) also requires an elongated or oblong pallet P and likewise requires the energization of the boom motor control valve 442 to cause the boom motor 146 to move the boom conveyor 86 longitudinally and likewise compensate for the elongation of the pattern of bags being stacked.

For clearness of disclosure of the invention, in FIG- URE 1 the hydraulic power unit 34 and the turntable driving unit 292 are shown as moved out into the space between the pallet dispenser 30 and the stacking conveyor 26. In the apparatus 20 as actually constructed, in order to conserve fioor space, the units 34 and 292 are mounted between the pallet dispensing unit 30.

What I claim is:

1. A filled-bag palletizer, comprising a bag stacker including a laterally-disposed rectilinear guideway, a laterally-movable bag stacker carriage mounted for reciprocation laterally along said guideway,

a bag-stacking conveyor elevator mounted on said carriage for motion upward and downward relatively thereto,

a bag-depositing conveyor mounted on said elevator at right angles to said guideway and having a bag outlet,

'3. pallet-receiving turntable mounted for rotation in a substantially fixed location at a substantially constant level and disposed beneath said outlet of said bagdepositing conveyor in bag-receiving relationship therewith,

power-operated means for reciprocating said carriage to and fro along said guideway laterally of said bagdepositing conveyor,

power-operated means for moving said bag-stacking conveyor elevator upward relatively to said carriage,

power-operated means for rotating said turntable to bring successive sectors thereof into registry with said outlet,

and a prime mover for actuating said means.

2. A filled-bag palletizer, according to claim 1, wherein said carriage-reciprocating means includes a hydraulic cylinder with a reciprocatory piston operatively connected to said carriage for reciprocation thereof relatively to said guideway and wherein said prime mover includes a motordriven hydraulic pump hydraulically connected to said cylinder for hydraulic actuation of said piston.

3. A filled-bag palletizer, according to claim 1, wherein said bag-depositing conveyor includes an elongated frame disposed substantially horizontally on said elevator and a substantially horizontal bag-depositing endless conveyor belt mounted longitudinally on said frame.

4. A filled-bag palletizer, according to claim 1, wherein there is provided a bag-feeding conveyor having an outlet coupled to said bag-depositing conveyor and movable laterally to and fro with said carriage and stacking conveyor.

5. A filled-bag palletizer, according to claim 3, wherein said bag-depositing conveyor includes adjustable bag guides disposed longitudinally of said frame in spaced parallel relationship relatively thereto and movably mounted within said frame on opposite sides of said lower endless conveyor belt, and also includes means for moving said bag guides toward and away from one another whereby to vary the separation thereof.

6. A filled-bag palletizer, according to claim 1, wherein said elevator includes an elongated longitudinal rectilinear guide structure mounted for upward and downward travel therewith, wherein said bag-depositing conveyor is movably mounted on said guide structure for longitudinal travel relatively to said elevator toward and away from said turntable, and wherein power-operated means is mounted on said elevator and operatively connected to said bag-depositing conveyor for effecting longitudinal travel thereof relatively to said guide structure.

7. A filled-bag palletizer, according to claim 1, wherein an empty-pallet dispenser is disposed in a fixed location adjacent said fixed location of said turntable with a pallet-supporting surface disposed at substantially the same level as the top surface of said turntable and has means thereon for storing a stack of empty pallets and also has a power-operated empty-pallet ejector disposed beneath said pallet-storing means and movable toward and away from said turntable in pallet-supplying rela tionship therewith.

8. A filled-bag palletizer, according to claim 7, wherein said turntable has a diametral passageway disposed beneath the top surface thereof, wherein said empty-pallet dispenser includes a fluid-pressure cylinder disposed beneath said empty pallet-storing means in alignment with said passageway in one position of rotation of said tumtable and having a reciprocable piston with a wheel rotatably mounted on the outer end thereof, wherein said pallet-storing means has a guideway disposed parallel to said cylinder with a tilting pallet pusher slidable therealong, and wherein an elongated flexible motion-transmitting member is anchored at one end to said palletstoring means and extends over said wheel to a connection with said pallet pusher.

9. A filled-bag palletizer, according to claim 4, wherein said bag-feeding conveyor has its forward end portion pivoted to said bag-depositing conveyor and has its rearward end portion swingable in response to the motion of said carriage and bag-depositing conveyor.

10. A filled-bag palletizer, according to claim 9, wherein an upstanding supporting structure is pivotally connected to the rearward end portion of said bag-feeding conveyor and has caster wheels thereon permitting free sliding and swinging motion thereof in response to the lateral reciprocation of said carriage and the upward and downward motion of said bag-depositing conveyor.

11. A filled-bag palletizer, according to claim 6, wherein there is provided a bag-feeding conveyor having an outlet disposed adjacent the inlet of said bag-depositing conveyor and having its forward portion pivotally coupled to said bag-depositing conveyor, and wherein an upstanding supporting structure is pivotally connected to the rearward end portion of said bag-feeding conveyor and has caster wheels thereon permitting free sliding and swinging motion thereof in response to the lateral reciprocation of said carriage and the upward and downward motion and longitudinal travel of said bag-depositing conveyor.

References Cited UNITED STATES PATENTS 2,675,928 4/ 1954 Slater 214-6 2,907,447 10/ 1959 Ofiutt et al 198-165 2,977,002 3/1961 Asp 214-6 3,143,222 8/1964 Caskie 214-6 3,170,564 2/1965 Gatto 198-165 3,223,253 12/1965 Garbe et al 214-6 3,291,010 12/1966 Williamson 214-6 FOREIGN PATENTS 827,324 2/1960 Great Britain. 116,200 1/ 1959 Russia.

GERALD M. FORLENZA, Primary Examiner. I. E. OLDS, R. J. SPAR, Assistant Examiners.

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