US3525443A - Counting and stacking apparatus - Google Patents

Description

Aug. 25', 1970 J. B. POMARA, JR coun'rme AND STACKING APPARATUS s Sheets-Sheet 1 Filed June 10. 1968 INVENTOR. Johnny B. Pomaru,Jr. BY +.W$=M

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Aug. 25, 1970 J. B. POMARA, JR

COUNTING AND STACKING AYPARATUS 3 Sheets-Sheet 2 Filed June 10, 1968 mum Fig.5

INVENTOR. Johnny B. Pamoro,Jr. BY

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coummc' AND STACKING AI'PPARATUS 1 68 Filed June 10 9 s Sheets-Sheet s v N F,

INVENTOR.

Johnny B1.Pq moro,Jr.

BY wmkm ATTORNEY United States Patent Office 3,525,443 Patented Aug. 25, 1970 3,525,443 COUNTING AND STACKIN G APPARATUS Johnny B. Pomara, Jr., Dallas, Tex., assignor of fifty percent to El Chico Corporation, Dallas, Tex., a corporation of Texas Continuation-impart of application Ser. No. 657,244, July 31, 1967. This application June 10, 1968, Ser. No.

Int. Cl. B65g 57/06 US. Cl. 214-6 4 Claims ABSTRACT OF THE DISCLOSURE Apparatus for counting and stacking substantially flat articles including a stacking conveyor, a stacking plate, a stacking guide, stack support and discharge plates, and a discharge conveyor. The stacking conveyor deposits each article on the stacking plate which immediately retracts dropping the article downwardly to the support and discharge plates which retract when a desired predetermined number of articles are stacked dropping the stack to the discharge conveyor.

This application is a continuation-in-part of an application entitled Counting and Stacking Apparatus filed by Johnny B. Pomara, Jr. on July 31, 1967, Ser. No. 657,244.

This invention relates to counting and stacking apparatus and particularly a system for counting and stacking substantially flat articles.

It is an object of the invention to provide new and improved apparatus for use in a packaging system for counting and stacking in vertically aligned relationship a predetermined number of substantially flat articles and discharging each stack toward a packaging station for placement in containers. The apparatus is especially adapted to counting and stacking of food products such as tortillas.

It is another object of the invention to provide apparatus of the character described wherein each stack of articles handled by the apparatus contains a predetermined number of such articles which number is variable by adjustment of counting and control means included in the apparatus.

It is still another object of the invention to provide apparatus of the character described which is especially adapted to handling soft, flexible, substantially flat articles with a minimum of folding and wrinkling.

It is another object of the invention to provide apparatus of the character described which includes stack supporting and discharge plate means movable between stack supporting and stack discharging positions.

It is a further object of the invention to provide counting and stacking apparatus of the character described including stacking plate means which momentarily supports and guides each stacked article between stacking conveyor and stack support and discharge plates below the stacking plate.

It is a still further object of the invention to provide apparatus of the character described which in its preferred form includes a stacking conveyor, stacking plate for receiving each article to be stacked from the stacking conveyor and momentarily supporting and discharging the article downwardly responsive to engagement of a trigger-like lever by each article as it moves to the stacking plate, a stacking guide for guiding and holding a stack of such articles in vertical aligned relationship, stack support and discharge plates means below the stacking guide and movable between stack supporting and stack discharging positions, for supporting the articles in stacked array, and a discharge conveyor for receiving each stack of articles for movement to a packaging station.

Additional objects and advantages of the invention will be readily apparent from reading the following description of apparatus constructed in accordance with the invention and by reference to the accompanying drawings thereof, wherein:

FIG. 1 is a side view in elevation of counting and stacking apparatus embodying the invention showing the stacking and the stack support and discharge plates at closed positions;

FIG. 2 is a top plan view of the apparatus of FIG. 1;

FIG. 3 is a top plan view of a portion of the apparatus of FIG. 1 as viewed from a plane generally along the line 3-3 of FIG. 1 illustrating the stack support and discharge plates at closed positions;

FIG. 4 is an enlarged fragmentary side view of a portion of the apparatus showing the stacking plate open or retracted for dropping a single article to the stack support and discharge plates which are at closed stack supporting positions;

FIG. 5 is a fragmentary side view partially in section, similar to FIG. 4, showing the stack support and discharge plates retracted or open for releasing a stack downwardly to the discharge conveyor and the stacking plate partially returned toward its closed position;

FIG. 6 is an enlarged fragmentary top view of the apparatus showing particularly the air spray system and the stacking plate at its closed position; and

FIG. 7 is a schematic circuit diagram of the electrical and air control and operating systems of the counting and stacking apparatus.

Referring to the drawings, a counting and stacking system 20' constructed in accordance with the invention includes a stacking conveyor 21, a stacking guide 22, a stacking plate 23, and stack support and discharge plates 24 and 25. A cooling conveyor 30 and a discharge conveyor 31 are shown for moving units to be counted and stacked to the system and for removing each stack of counted units from the system to a remote location, such as a packaging station, not shown. Units being handled by the apparatus, such as the circular units 32, are fed into the system on the cooling conveyor 30 at the upper end of which each unit is deposited on a line-up slide 33 which guides them to and deposits them on the stacking conveyor 21. The conveyor 21 propels each unit onto the top face of the stacking plate which retracts to drop each unit downwardly in the stacking guide 22 to the stack support and discharge plates 24 and 25. When the desired predetermined number of units has been deposited and stacked in aligned relationship on the plates 24 and 25 the plates are rapidly retracted or opened away from each other dropping a stack 32a of the units to the discharge conveyor 31 which moves the stack in the direction of the arrow 34 away from the counting and stacking system toward additional process apparatus such as a packaging station, not shown. The counting and stacking system, particularly when handling tortillas, is generally located between ovens in which the tortillas are cooked and a packaging station at which they are placed in containers for shipment.

The cooling conveyor 30 is a suitable conventional conveyor having legs 35 and 40 of suitable length to provide the desired height and slope to the conveyor. The legs 35 and 40 are provided with adjustable foot members 35a and 40a respectively, to permit minor height and attitude adjustments to the conveyor. The supporting structure for the endless flexible belt 41 of the conveyor 30 includes side beams 42 which hold suitable belt supporting rollers 43 mounted on end bearings 44. The belt is driven by suitable conventional power means, not shown.

The discharge conveyor 31 is also a conventional conveyor including a flexible endless belt 45, supported on spaced end rollers 50 and 51 which are mounted between parallel, spaced, side beams 52. The roller 50 is supported on bearings 53 which are each movable in an H-frame 54 by adjustment of a screw 55 to maintain the proper tension in the conveyor belt. The roller 51 is supported on bearings 60 and is connected at one end with a gear 62 driven by a chain 63 extending to a prime mover, such as an electric motor, not shown, for operating the conveyor. The discharge conveyor is mounted on spaced legs 64 secured along their upper ends to the beams 52 and supported at their lower ends on adjustable foot members 65. The legs 64 are connected and braced by horizontally extending lower side members 70 which also support portions of the controls for the system as explained in detail below. Upper horizontal side braces 71 extend between the legs 64 and the legs 40 of the conveyor 30.

The line-up slide 33 which guides each item from the conveyor 30 to the stacking conveyor 32 includes a main panel or bottom 80 providing a top sliding surface 81 between side upturned flange or edge portions 82 which aid in guiding the items down the slide and prevent sliding ofl? the slide laterally. The slide is slightly wider at the top end than at the bottom end to permit some tolerance in the positioning of the items on the conveyor 30 so that if they are displaced laterally on the conveyor to one side or the other of the center of the slide, they still generally will be fed into the slide at its upper end. The more narrow lower end of the slide, however, causes each item to be properly centrally positioned along the centerline of the stacking conveyor. The top surface of the slide preferably is coated with a suitable material such as a plastic sold under the trademark Teflon to enhance the sliding characteristics of the surface so that each item properly accelerates down the slide and does not tend to stick on the surface of the slide. The slide is supported on frame members 83 which are mounted on the ends of side plates 82 of the stacking conveyor 21.

The stacking conveyor 21 has an endless flexible belt 85 movably supported on spaced end rollers 90 and 91 which are mounted on bearings 90a and 910, respectively, secured to the side plates 84 of the conveyor. The side plates are suitably supported from integral brackets 92 and 93 which extend to and are connected with the side plates 52 of the discharge conveyor. The conveyor belt 85 comprises a suitable flexible wire mesh material which provides maximum cooling of food items as they move from the slide toward the stacking plate and guide.

The stacking guide 22 is a U-shaped member having leg portions extending toward the stacking conveyor and secured along inwardly turned leg-end flanges 100, FIG. 6, to a cross member 101 extending between the side plates 84 of the stacking conveyor. The stacking guide defines a vertical opening or passage 22a slightly larger than the items being stacked in it. Each item passes into the upper end of the opening from the stacking conveyor and is confined in the opening in stacked array on the plates 24 and 25 until released by opening the plates apart. The stacking guide has a horizontal slot 102 opening toward the stacking plate 23 and positioned and of suflicient height to freely receive the horizontally moving stacking plate to permit the plate to move between the closed positions of FIGS. 1, 2, and 6 and the open position of FIG. 4. Guide blocks 103 and 104 are mounted in spaced relationship along the outside surface of the bight of the U-shaped stacking guide above and below the slot 103 to guide the stacking plate back into the slot as it moves from its maximum open position of FIG. 4 back toward its closed position as in FIG. 5. The guide blocks minimize the possibility of the stacking plate becoming misaligned from the mouth of the slot when at its maximum open or retracted position due to possible vertical deflection which in the absence of the guide blocks might cause the plate to miss the slot and jam against the outer surface of the stacking guide. The guide blocks thus allow complete withdrawal of the stacking plate from the opening 22a through the stacking guide. Similarly the guide blocks 105 and are secured adjacent to the lower edge of the stacking guide to prevent jamming of either of the plates 24 and 25 against the stacking guide in the event of upward deflection of the plates and thus allow complete withdrawal of the plates from below the lower open end of the stacking guide so that a stack 32a of items in the guide on the plates 24 and 25 may drop downwardly without interference from either of the plates. The stacking guide insures substantial vertical alignment of the stacked items on the stack support and discharge plates.

The stacking plate 23 is mounted on the end of a piston rod connected with a piston 120a in a double acting air cylinder 121 for supporting and moving the stacking plate between its open and closed positions. The air cylinder is secured through a fitting 122 at one end connected on an L-shaped bracket 123 having an up turned end portion 124 secured with the end of the cylinder near the stacking plate to provide vertical support and stability to the cylinder. The bracket 123 is supported on a mount 124 which spans the discharge conveyor and has vertical legs 125 extending dowwardly and connected with the side plates 52 of the discharge conveyor. The piston rod 120 of the air cylinder 121 is extended and retracted for closing and opening the stacking plate 23, or for moving the stacking plate between its stacking and release positions, responsive to air pressure supplied to opposite ends of the cylinder by lines and 131 which are connected with an electrically operated air valve 132 communicating through a line 132a with a tank 133 from which air under pressure is selectively supplied through the valve for extending and retracting the air cylinder piston rod.

The movement of the stacking plate 23 is controlled by a hair-like lever or feeler 134 supported from and actuating a micro-switch 135 which simultaneously controls operation of the air cylinder 121 and an air head which supplies jets of air downwardly against each item on the stacking plate 23 as the plate is retracted so that the item is forced rapidly and evenly downwardly to its stacked relationship on the plates 24 and 25. The microswitch and air head are both supported over the open upper end of the stacking guide 22 from a cross angle bar 141 secured at opposite ends to the side plates 84 of the stacking conveyor. The micro-switch is connected to the vertical side surface of a bracket 142 which is suitably secured as by welding at one end to the cross bar 141. The air head is supported from the bracket 142 by a clamp 143 secured to the bracket and to a supporting supply line 144 connected with the air head. The air head includes a cross connection 145 secured to identical valves each of which supplies, supports, and controls air flow to a downwardly projecting jet tube or nozzle 151. The three nozzles used in this particular form of air head are spaced to distribute downwardly flowing air from the nozzles over the top surface area of the items handled by the apparatus so that there is a substantial balance of air pressure against each item forcing each item downwardly from the stacking plate when it is rapidly withdrawn responsive to the movement of the lever 134 on the micro-switch.

The air supply line 144 leading to the air head 140 is connected through an electrically operated air valve 152 into the air tank 133. The lever 134 on the microswitch extends downwardly to a substantial depth within the stacking guide 22 to insure that when an item to be stacked is launched from the stacking conveyor into the stacking guide the lever is contacted by the item. An elongate slot 23a, FIG. 6, is provided in the stacking plate 23 opening toward the lever 134 and positioned in the plate to receive the lever as the plate moves toward and away from its closed position. As shown in FIGS. 1 and 5 the lower end of the lever extends somewhat below the stacking plate. The slot 23a is of sufiicient width and length to preclude any interference between the lever and the plate so that any normal flexing of the lever during operating of the apparatus either by way of vibration or by engagement by the items being stacked, will not cause the lever to jam or otherwise interfere with the stacking plate. The stacking plate freely moves over and is retracted from the lever during its horizontal movements between its fully closed position shown in FIGS. 1 and 6 and its fully retracted position of FIG. 4. The lever 134 is flexible and somewhat fragile so that it is easily deflected upwardly by an item, such as a tortilla, projected downwardly and outwardly against its lower surface from the stacking conveyor.

The stack support and discharge plates 24 and 25 are operably supported from identical double acting air cylinders 160 and 161, respectively, for moving the stacking plates between stack supporting and stack discharging positions. The cylinder 160 supports the stacking plate 24 on a piston rod 162 connected with a piston 163 which is displaced between end positions by air under pressure selectively supplied to opposite ends of the cylinder through lines 164 and 165, respectively, which are connected with an electrically operated control valve 170 for supplying air from the air tank 133 to the air cylinder to move the plate 24 in both opening and closing directions. The air cylinder 160 is secured by bracket 166 on a cross member 167 which spans the discharge conveyor belt and has vertical leg portions 168 secured to the side beams 52 of the discharge conveyor. Similarly, the stacking plate 25 is supported on piston rod 171 of the air cylinder 161. A piston 172 connected with the piston rod 171 is similarly displaced in opposite directions by air selectively supplied from the valve 170 to the air cylinder 161 through lines 173 and 174 connected between the valve and the air cylinder. The air cylinder 161 is secured on a bracket 175 mounted on a lateral support 180 also spanning the discharge conveyor belt and having leg end portions 181 connected with the side beams 52 of the discharge conveyor.

The stacking plates 24 and 25 with their related air cylinder units are positioned such that the adjacent end edges of the plates are closely spaced from each other when the plates are at closed stack supporting positions as shown in FIG. 4 so that a stack on the plates is substantially equally supported by both of the plates. The stroke of each of the air cylinder pistons is of a length to retract each of the plates to an open position at which the adjacent end edges of the plates are clear of the lower open end of the stacking guide 22 to allow a stack to be freely discharged downwardly from the guide as evident in FIG. 5. The plates 24 and 25 are substantially in the same plane and remain in such plane during their horizontal movement between open and closed positions. The plates are retracted so rapidly that a stack supported on them is released to drop in a horizontal position to the discharge conveyor belt.

A counting switch 224 is supported from a bracket 225 secured with the bracket 123 below the stacking plate 23. The counting switch has a lever 230 engageable by the stacking plate 23 each time the plate retracts for dropping an item downwardly as illustrated in FIG. 4. When the stacking plate is returned to its fully closed position as in FIGS. 1 and 6 the counting switch is released by the stacking plate. The counting switch is interconnected with a counter unit 273 and a time delay relay 274 for operation of the stacking and discharge plates when a desired predetermined number of items have been stacked on the plate.

The electrical and air systems circuitry for controlling the operation of the counting and stacking apparatus are illustrated schematically in FIG. 7. For purposes of clarity the electrical conductors of FIG. 7 are not all shown in all of the other figures of the drawings. It is to be understood, however, that electrical conductors and air lines as shown in FIG. 7 are interconnected between the various electrical and air components of the apparatus for supplying air under pressure to the various air cylinders and properly timing the operations of the cylinders. The circuitry controls the movement of the stacking plate 23, the air flow from the air head 140, and the opening and closing of the stack support and discharge plates 24 and 25 in accordance with a desired program for which the adjustable control components of the system are set. One suitable counter 273 is a Cycle-Flex counter, series HZl, manufactured by Bliss-Eagle Signal, a division of E. W. Bliss Company, Davenport, Iowa. The time delay relay 274 may be a model 10337Hl92A, 60 cycle, made by Cutler-Hammer, Inc.

The counter 273 includes a counting assembly 280 having a stepping motor which advances one step each time it is deeuergized. The stepping motor is mechanically coupled with a solenoid actuated clutch 281 having a solenoid coil 281a which, when energized as described below, causes the counting assembly to reset to zero preparatory to starting the next counting cycle. The counting assembly is coupled with a switch 282 included in the counter which when closed connects the counting switch 224 in a circuit with the counting assembly 280. The counting assembly is also coupled with a switch 283 included in the counter which energizes the time delay relay 274. The time delay relay includes a solenoid coil 284 which when energized causes its contacts 285 and 290 to close to energize both the solenoid 281a of the clutch 281 of the counter and a solenoid coil 271a of the air valve 170. The time delay relay includes a bellows, not shown, having an air bleed hole which allows air to be drawn into and expelled from the bellows at an adjustable rate to control the expansion and contraction of the bellows which is moved in one direction by the coil 284 when energized. The coil 284 moves the bellows and closes the contacts 285 and 290 with the rate of air flow through the bleed hole in the bellows con trolling the return rate of movement of the bellows in the opposite direction for opening the contacts 285 and 290 after a predetermined time delay controlled by the bellows. The counter 273, the time delay relay 274, and the air valve 170 are connected with main line conductors 291 and 292 extending to a suitable volt, 60 cycle, power supply 292a, as explained in more detail below.

One side of the counting switch 224 is connected to the main line conductor 292 by a conductor 293. The other side of the counting switch is connected by a conductor 294 to one side of the switch 282 in the counter unit 273. The other side of the switch 282 is connected by a conductor 295 to one side of the motor of the counting assembly 280'the other side of which is connected by conductors 300 and 301 to the other main line conductor 291. One side of the clutch solenoid 281a is connected by the conductor 291 to the conductor 30.1 and the other side of the clutch solenoid is connected by a conductor 302 to one side of the contact 285 of the time delay relay 274. The other side of this contact 285 is connected by a conductor 303 to the main line 292. The time delay relay winding 284 is connectable across the main line conductors by way of the conductor 304, the switch 283 of the counter and the conductors 305 and 310. When energized the winding 284 causes both the contacts 285 and 290 to move to close position.

The solenoid 271a of the air valve 170 is connected on one side with the main line conductor 292 through the conductor 311, the contact 290, and the conductor 312. The other side of the solenoid 271a is connected with the main line conductor 291 by the conductor 313 so that closure of the contact 290 energizes the solenoid.

The micro-switch 135 which controls the operation of the stacking plate 23 and the air head 140 is connected on one side to the main line conductor 291 and on the other side to conductors 314 and 314 leading to the solenoid coil 132a of the air valve 132 for the stacking plate and the solenoid 152a of the air valve 152 for the air head 140, respectively. The other sides of the solenoid coils 132a and 152a are connected with the main line conductor 292 by conductors 320 and 321, respectively, so that when the switch 135 is closed by the lever 134 the solenoids for both the air valve for the stacking plate and the air head over the stacking plate are energized.

The air valve 132 has a movable valve member 132k provided with an air supply passage network .1320 which connects the air supply tank 133 with the air line 130 at one end position of the valve member and connects the air supply tank with the other air line 131 at the other end position of the valve member. The valve member has exhaust passages 132d and 132a which selectively communicate with the air lines 130 and 131, respectively, and corresponding exhaust ports in the air valve cylinder for exhausting one end of the air cylinder 121 while air under pressure is supplied through the valve 132 to the other end of the cylinder. For example, in the position illustrated in FIG. 7 the end of the air cylinder 121 nearest the stacking plate 23 is exhausted through the line 131 and the exhaust passage 1322 while air under pressure is supplied to the other end of the air cylinder from the supply tank through the flow passage network 1320 and the air line 130 for holding the stacking plate 23 at its closed position at which the piston rod 120 is fully extended. The piston rod is retracted and the stacking plate moved to its open position by shifting the valve member 132b to its other end position at which air under pressure is supplied to the line 131 through the air flow network 1320 while air is exhausted from the air cylinder 121 through the air line .130 and the exhaust flow passage 132d in the valve member.

Air is supplied to the stacking and discharge plate air cylinders 160 and 161 through the air valve 170 which has a movable valve member 170a having an air supply passage network 17% and exhaust passages 1700 and 17011. Air is supplied to the far or outward ends of the air cylinders 160 and .161 through the air lines 164 and 174 which connect with a line 166 leading to the valve 170 so that when the valve member 170a is in the position shown in FIG. 7 air is supplied from the air tank 133 through the flow passage network 17% to the line 166 and connecting lines 164 and 174 to the far ends of the air cylinders 160 and 161 forcing the pistons 163 and 172 toward each other and holding the stacking plates 24 and 25 at their closed adjacent positions. At this position of the air valve member the near or inward ends of the air cylinders 160 and 161 are vented to the atmosphere through the air lines 165 and 173 which connect with a line 167 to the air valve which vents the line 167 to the atmosphere through the passage 1700! of the valve member 170a. When the air valve member 170a is shifted by its solenoid coil 271a to its other end position the supply tank is communicated through the flow passage network 17% with the line 167 and the connecting lines 165 and 173 applying air under pressure into the near ends of the air cylinders 160 and 161 and venting the outward ends of the air cylinders to the atmosphere through the line 164, 174, and .166, and through the air valve member exhaust passage 1700. At this position of the air valve the pistons 163 and 172 are moved apart thereby retracting the piston rods 162 and 171 shifting the plates 24 and 25 apart to their open positions.

The air head 140 communicates with the air supply tank 133 through the line 144 and the air valve 152 which has a valve member 1521) movable by the solenoid 152a. The valve member has an air supply passage 152a for communicating the air tank with the line 144 at one position of the valve member and a vent passage 152d which vents the air head system at the other position of the valve member, as shown in FIG. 7.

The various switches, contacts, air valves, and the like are normally positioned as illustrated in FIG. 7. The clutch 281 of the counter 273 and the time delay relay 274 are not activated and the solenoids of the air valves 132 and 170 are all deenergized since the switch 283 is open. With the switch 283 open, the relay winding 284 is not energized so that the contacts 285 and 290 of the time delay relay are at open positions. With the contacts 285 and 290 open no power is supplied to the solenoid 281a of the counter and the solenoid of the air valve 170. With the air valve solenoid 271a deenergized its valve member 170a is positioned as shown in FIG. 7 so that the air pressure in the opposite ends of the pistons 1'60 and 161 maintain the plates 24 and 25 at their closed, stack receiving positions. Similarly, with the switch 135 open the solenoids 132a and 152a of the air valves 132 and 152, respectively, are deenergized and their valve memhers are positioned as illustrated so that the stacking plate 23 is held at its closed position and no air is supplied through the air valve 152 to the air head 140 above the stacking plate.

As each article processed by the apparatus is launched from the stacking conveyor belt into the stacking guide 22 onto the stacking plate, the micro-switch lever 134 is contacted by the item and raised thereby closing the micro-switch 135 energizing the solenoid 132a of the air valve 132 for the stacking plate 23 and the solenoid 152a of the air valve 152 for the air head 140. The air valve member 132a is shifted to its other end position supplying air to the air cylinder 121 through the line 131 moving the stacking plate from the closed position of FIGS. 1 and 2 to the open position of FIG. 4. Simultaneously with the opening of the stacking plate the solenoid of the air valve 152 shifts the valve member 152b to supply air through the nozzles 151 providing a high velocity air blast downwardly against the top face of the item on the stacking plate so that as the stacking plate is rapidly retracted or withdrawn from beneath the item the air blast forces the item downwardly increasing its velocity over the normal falling rate of the item after the stacking plate is withdrawn from beneath it. The item drops downwardly within the stacking guide 22 to the stack support and discharge plates 24 and 25. As the stacking plate 23 is retracted to the position of FIG. 4 the lower surface of the plate engages the lever 230 on the counting switch 224 closing the switch and energizing the motor of the counting assembly 280 so that when the counting switch is released by return of the stacking plate to its closed position opening the circuit through the counting switch and the assembly 280, the counting device advances one step.

As the item drops downwardly to the stack support and discharge plates, the lever 134 returns downwardly opening the micro-switch 135 deenergizing the solenoids 132a and 152a and returning the valve member of the air valve 132 to its normal position to supply air to the cylinder 121 through the line moving the stacking plate back to its normal closed position in the stacking guide. The deenergizing of the solenoid 152a returns the air valve 152 to the position shown in FIG. 7 shutting off the downward air flow from the nozzles 151. As the stacking plate 23 returns to its closed position the counting switch lever 230 on the micro-switch 224 is released opening the switch and the circuit through the switch and the assembly 280 so that the counting device in the counter 27 3 advances one step.

The supplying of the items to be counted and stacked on the stacking conveyor continues with each item being dropped downwardly one at a time by the retraction of the stacking plate 23 until the desired number of items for which the counter is set has been deposited by the stacking plate on the stack support and discharge plates 24 and 25. At that time the counting assembly 280 moves the switch 282 to its open position and momentarily closes the switch 283 connecting the relay winding 284 across the main line conductors. This momentary energizing of the winding 284 closes the contacts 285 and 290 connecting the solenoid 281a of the clutch 281 and the solenoid 271a of the air valve 170 across the main line. Energizing the solenoid 271a shifts the air valve 170 to its other end position for supplying air to the inward or near ends of the air cylinders 160 and 161 thereby closing the air cylinders and moving the stack support and discharge plates 24 and 25 apart from each other to their open positions dropping the stack downwardly from the stacking guide to the discharge conveyor below the stacking guide and plates. FIG. 5 illustrates the position of the stack support and discharge plates at their fully opened positions for releasing a stack downwardly from the plates. Since the stacking plate 23 operates responsive to the lever 134 and independently of the counter, the plate 23 returns to closed position after dropping each item; and thus when the plates 24 and 25 are open to drop a counted stack, the plate 23 generally will be already returning to closed position as in FIG. 5.

The air cylinders remain closed with the stacking plates open so long as the solenoid coil 271a of the air valve 170 is energized. The closing of the switch 283 only momentarily energizes the relay winding 284 which is then immediately deenergized. The contacts 285 and 290, however, are held at their closed positions by the bellows of the relay with the rate of air flow through the bellows controlling the opening of the contacts. The time delay relay 274 is adjusted to hold the contacts 289 and 290 closed for a sufficient length of time for the complete stack of items to drop downwardly from the open stack support plates to the discharge conveyor below. The closed contact 285 maintains the solenoid 281a of the clutch 281 energized to cause the counter to reset to zero for beginning the next counting sequence. While the clutch is so energized for the counter to reset itself to zero, opening and closing of the counting switch 284 has no effect on the counter. This period of time is, however, extremely short and less than the time of arrival of subsequent or following items from the stacking conveyor so that the counter is reset for counting between the last item of one stack and the first of the next stack. When the predetermined time for which the time delay relay has been set has expired, the contacts 285 and 290 of the relay are reopened, deenergizing the clutch solenoid 281, and the air valve solenoid 170a so that the air valve member 17011 of the air valve is returned to its other end position for supplying air to the opposite ends of the air cylinders 160 and 161 extending the pistons to their open positions and thus returning the plates 24 and 25 to their stack supporting closed positions. Simultaneously, the deenergizing of the clutch solenoid releases the clutch allowing the counter to start a new counting sequence. Thus, the system begins another sequence of counting a predetermined number of the items stacking them and depositing them on the discharge conveyor.

The counting and stacking system is particularly well suited to the handling of tortillas, which are a Mexican food product in the form of a thin unleavened cake which may be served either in a soft flexible form or a hard brittle toasted form. The counting and stacking apparatus is especially efiective in packaging the soft flexible form of the tortilla. Tortillas are generally cooked in a conveyortype oven, not shown, in which they are moved on a conveyor spaced one from the other in a line along a belt type conveyor. The tortillas are moved from the oven on a suitable cooling conveyor which may comprise the conveyor 30 a portion of which is shown in FIGS. 1 and 2. The cooling conveyor allows the tortillas to cool to the desired degree and feeds them to the counting and stacking apparatus 20. The cooling conveyor delivers the line of the tortillas 32 one at a time to the upper end of the conveyor where they are discharged downwardly onto the upper end of the slide 33 which delivers the tortillas in sequential aligned relationship to the stacking conveyor 84. The wide upper end of the slide permits some misalignment of the tortillas on the cooling conveyor while the narrow lower end of the slide assures alignment of the tortillas on the stacking conveyor with the stacking guide 22 The line of tortillas is conveyed along the belt of the stacking conveyor to the opposite end of the conveyor where each tortilla is launched or projected outwardly and downwardly from the conveyor into the stacking guide 22 where the tortilla strikes the stacking plate 23 and engages the microswitch lever 134 which sets in motion the previously described electrical and air control system for retracting the stacking plate and initiating the downward air blast from the air head 140. The tortilla momentarily comes to rest on the stacking plate for a sufficiently brief time to orient it at a substantial horizontal position, immediately following which the stacking plate is rapidly retracted from beneath the tortilla and air is blown downwardly from the nozzles 151 to push the tortilla downwardly to the stack support plates 24 and 25. Partial confinement of air within the stacking guide below the dropping tortilla provides a cushioning etfect which eases the tortilla onto the previously stacked one minimizing damage, wrinkling, and other possible deformations of the tortilla. When the desired number for which the counter has been set has been delivered to and dropped by the stacking plate and arranged in stacked form within the stacking guide on the stack support plates, the stack support plates are rapidly retracted to their open positions allowing the stack of tortillas to drop downwardly to the discharge conveyor belt 31 which moves the stack in the direction of the arrow 34 for further processing such as packing in boxes and the like. The complete sequences of operation of the stacking plate 23 and the stack support and discharge plates 24 and 25 are completely repeated for each stack of tortillas arranged and discharged to the discharge conveyor. If, for example, each stack of tortillas contains twelve tortillas, the stacking plate 23 and the air head operate twelve times for each stack, the plate withdrawing and the air head blowing downwardly each time a tortilla is deposited in the stacking guide, while the stack support and discharge plates 24 and 25 move to their open positions once for each stack of twelve tortillas as the stack is released to the discharge conveyor.

The rates of speed of the various conveyors are coordinated with the control system of the apparatus so that the process beginning with the supply of tortillas on the cooling conveyor through the removal of the stacks by the discharge conveyor proceeds in a systematic time sequence without the overlapping of stacks and other related problems. The counter 273 may, of course, be adjusted within certain limits to provide stacks of any desired number within the structural limitations of the apparatus which includes such factors as the height of the stack support plates above the discharge conveyor.

The counting and stacking apparatus has been illustrated and described in terms of a single unit. Multiple units in side-'by-side relationship may be used to process several rows of items disposed in generally parallel relationship. For example, where a tortilla oven utilizes a conveyor carrying three rows of tortillas the counting and stacking apparatus may provide for simultaneously counting and stacking items in each of the rows of tortillas as they are delivered by the cooling conveyor to the apparatus. Such 1 1 a multiple application requires a separate line-up slide and separate assemblies of a stacking plate, a stacking guide, and stack support and discharge plates with related control systems for each line of tortillas handled. A single stacking conveyor and a single discharge conveyor may, however, be combined with the stacking and counting apparatus with three rows of tortillas arranged side-byside on the stacking conveyor and three rows of stacked tortillas arranged side-by-side moved away on the discharge conveyor. Also, a single air supply may be used for furnishing air to the three separate control systems of the three separate counting and stacking arrangements.

Other modifications within the scope of the invention will be obvious to those skilled in the art, such, for example, the use of a single stack support and discharge plate in lieu of the preferred oppositely moving pair of discharge plates described and illustrated herein. Obviously, such a single plate must be larger, will involve movement of more mass, and would require more rapid movement to properly release a stack to the discharge conveyor without affecting the horizontal position of the stack as it is dropped.

It will now be seen that a new and improved system for counting and stacking has been described and illustrated. It will also be seen that the apparatus is particularly adapted to the handling of substantially flat items and especially such items as food products such as tortillas of the soft variety. It will be further seen that the system arranges a desired number of items in stacked aligned relationship and moves each stack to a location for further processing, such as packing in containers and the like. It will also be seen that the counting and stacking apparatus includes a stacking conveyor, a stacking plate for lining up and dropping each handled item into stacked relationship below the stacking plate, stack support and discharge plates below the stacking plate for holding each stack of items until the stack comprises the desired number and then discharging the stack to a discharge conveyor below the stack support and discharge plates for movement to a location for a further processing, such as packing in containers. In its preferred arrangement the counting and stacking apparatus is used with a supply conveyor which in the case of tortilla handling is a cooling conveyor from a cooking oven and a line-up slide for delivering the items from the supply conveyor to the stacking conveyor of the apparatus so that the items are properly aligned on the stacking conveyor for deposit on the stacking plate.

The foregoing description of the invention is explanatory only and changes in the details of the construction illustrated may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. Apparatus for counting and stacking a plurality of substantially flat flexible articles comprising: supply means for feeding said articles into said apparatus comprising an endless belt-type conveyor for depositing said articles one at a time into said apparatus; stacking means comprising a substantially horizontal plate rapidly reciprocable along a straight line in the direction of movement of said endless belt-type conveyor to individually receive each of said articles from the discharge end of said conveyor, to momentarily support each of said articles, and to release each of said articles to drop downwardly to a stacked relationship below said plate, said plate being disposed immediately adjacent to the discharge end Of said endless belt-type conveyor at a first position for receiving and supporting each of said articles individually and being movable away from said discharge end of said conveyor to a second article release position spaced from said discharge end of said conveyor and returnable along said line to said first position; stack support and discharge means comprising a horizontally recip'rocable plate for receiving said articles from said stacking means, holding said articles in stacked relation-v ship, and discharging said articles in said stacked relation ship when a desired predetermined number of said articles are stacked thereon; a stacking guide disposed between said stacking means and said stack support and discharge means for engagement by edges of said articles for maintaining substantially vertical alignment of said articles and holding said stacked articles in place on said stack support and discharge means; air means supported above said stacking means for discharging an air stream downwardly against each article on said stacking means as said stacking means moves from said first article supporting position to said second article release position; a discharge conveyor for receiving each stack of articles from said stack support and discharge means and moving said stack toward a location for further processing; and counting means operatively associated with said stacking means and said stack support and discharge means and actuated by movement of said stacking plate for controlling the operation of said stacking means and said stack support and discharge means when a predetermined number of said articles is deposited on said stack support and discharge means by said stacking means.

2. Apparatus for counting and stacking soft tortilla food products comprising: a sloping line-up slide for receiving randomly positioned tortillas at an upper end thereof from a cooling conveyor and discharging said tortillas in aligned positions at a lower end thereof; an endless belt-type feeding and stacking conveyor at said lower end of said slide for receiving each tortilla from said slide and moving said tortilla to and discharging said tortilla from the end of said conveyor opposite said slide; a substantially horizontally positioned rapidly reciprocable stacking plate movable along the same straight line of direction as said feeding and stacking conveyor and closely spaced from and below the discharge end of said stacking conveyor below the carrying plane surface of said conveyor, said stacking plate being adapted to be horizontally moved from a first tortilla receiving position closely spaced from said feeding and stacking conveyor where it is normally located in a direction away from said conveyor to a second tortilla release position distantly spaced from said conveyor whereby a tortilla momentarily supported on said stacking plate is released for dropping downwardly to a stacked relationship below said plate, said stacking plate being adapted to be rapidly retracted from said first position to said second position and being surfaced such that the rapid removal of said plate strips a tortilla supported on said plate such that the horizontal position of said tortilla is unaffected by the withdrawal of said plate whereby said tortilla is dropped in a substantially horizontal position into said stacked relationship below said plate; a stack support and discharge plate disposed in a substantially horizontal position below said stacking plate and adapted to horizontally reciprocate in the same direction as said stacking plate between a first stack supporting position below said first position of said stacking plate and a second stack discharge position spaced therefrom for releasing a stack of tortillas supported thereon to permit said stack to drop downwardly therefrom; a stacking guide supported between said stacking plate and said stack support and discharge plate engageable by edges of said tortillas for holding a stack of tortillas in substantially vertical aligned stacked relationship on said stack support and discharge plate; a discharge conveyor disposed below said stack .support and discharge plate for receiving each stack of tortillas released by said plate and moving said stack away from said apparatus toward a packaging station; switch means associated with said stacking plate including an actuating feeler disposed over said stacking plate within the line of trajectory of a tortilla propelled from the discharge end of said feeding and stacking conveyor onto said stacking plate whereby each said tortilla engages said feeler to effect retraction of said stacking plate when said tortilla is supported on the top surface of said stacking plate for moving said stacking plate to said second position to release said tortilla for dropping downwardly in said stacking guide to said stack support and discharge plate; and counting means responsive to said switch means and adapted to effect retraction of said stack support and discharge plate to said second stack release position when a predetermined number of tortillas are released to stacked position on said stack support and discharge plate by said stacking plate.

3. A tortilla counting and stacking apparatus as defined in claim 2 wherein said stacking plate is provided with a longitudinal slot extending in the direction of movement of said plate and open at one end through the edge of said plate toward the discharge end of said feeding and stacking conveyor, and said actuating feeler of said switch means is disposed through said slot of said stacking plate when said stacking plate is at said first tortilla receiving position closely spaced from said discharge end of said feeding and stacking conveyor whereby said feeler is engaged by each tortilla propelled from said feeding and stacking conveyor onto the top surface of said stacking plate.

4. A tortilla counting and stacking apparatus as defined in claim 3 wherein said stacking plate has a smooth top supporting surface to provide maximum stripping action between each tortilla supported on said plate when said plate is'retracted to said second position.

References Cited UNITED STATES PATENTS 1,563,071 11/ 1925 Brecknell.

2,191,881 2/ 1940 Erikson et a1. 271-88 2,492,024 12/ 1949 McWilliams.

2,697,388 12/ 1954 Hansen et a1.

3,054,516 9/1962 Joa.

3,231,100 1/1966 Faeber.

3,233,891 2/1966 Denton et a1. 271-88 X 3,291,010 12/1966 Williamson.

3,392,853 7/1968 Mitchell et a1.

3,393,645 7/1968 Mason.

3,412,875 11/1968 Weir.

1,826,379 10/1931 Birkmeyer et a1. 19845 X 2,596,228 5/1952 Fletcher 19845 X 2,637,450 5/ 1953 Eshelman.

3,3,66,25 3 1/ 1968 Walchhiiter.

GERALD M. FORLENZA, Primary Examiner R. J. SPAR, Assistant Examiner US. Cl. X.R. 19845; 27168

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