US3702696A

US3702696A - Apparatus for folding and stacking flexible sheets

Info

Publication number: US3702696A
Application number: US116438A
Authority: US
Inventors: Richard K Teed
Original assignee: Riegel Textile Corp
Current assignee: MOUNT VERNON MILLS Inc A CORP OF
Priority date: 1971-02-18
Filing date: 1971-02-18
Publication date: 1972-11-14
Anticipated expiration: 1989-11-14

Abstract

AN APPARATUS FOR SEQUENTIALLY FOLDING AND STACKING INDIVIDUALLY RECEIVED SHEETS OF A FLEXIBLE MATERIAL TO PREPARE COUNTED STACKS OF THE FOLDED SHEETS FOR SUBSEQUENT PACKAGING. THE ILLUSTRATED EMBODIMENT OF THE APPARATUS INCLUDES MEANS FOR CONVEYING THE INDIVIDUAL SHEETS ALONG A PATH OF TRAVEL, FIRST TRANSVERSE FOLDING MEANS POSITIONED INTERMEDIATE THE PATH OF TRAVEL FOR FOLDING EACH SHEET UPON ITSELF ALONG A TRANSVERSE FOLD LINE, SECOND TRANSVERSE FOLDING MEANS POSITIONED INTERMEDIATE THE PATH OF TRAVEL AND SUBSEQUENT TO THE FIRST FOLDING MEANS FOR IMPARTING A SECOND TRANSVERSE FOLD, AND LONGITUDINAL FOLDING MEANS ADJACENT THE TERMINAL END OF THE PATH OF TRAVEL FOR IMPARTING A LONGITUDIANL FOLD. THE THUS FOLDED SHEETS ARE THEN DELIVERED TO A PLATFORM WHICH SEQUENCES DOWNWARDLY UPON RECEIVING EACH FOLDED SHEET SUCH THAT THE LEVEL AT WHICH THE FOLDED SHEETS ARE RECEIVED ON THE PLATFORM REMAINS SUBSTANTIALLY CONSTANT. WHEN THE PLATFORM REACHES ITS LOWEST POSITION A DELIVERY BELT IS ACUATED TO REMOVE THE STACK OF FOLDED SHEETS FROM THE PLATFORM AND TRANSPORT THE SAME TO A PACKAGING STATION.

Description

Nov. 14,1972 R. K. TEED 3,702,696

APPARATUS FOR FOLDING AND STAGKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 1 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 2 Nov. 14, 1972 v R. K. TEED 3,702,695

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 5 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 4 R. K. TEED Nov. 14,1972

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 5 R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 6 Nov. 14, 1972 I T D 3,702,695

APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 7 III i 0 Z" 'J) HZ @Z) 58 LOG-1C RELAY Moouue Loam: \"\ooul e R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS FiledFeb. 18, 1971 9 Sheets-Sheet 8 momsow ma :mmmma R. K. TEED Nov. 14, 1972 APPARATUS FOR FOLDING AND STACKING FLEXIBLE SHEETS Filed Feb. 18, 1971 9 Sheets-Sheet 9 wdammwua United States Patent Oflice 3,702,696 Patented Nov. 14, 1972 US. Cl. 270-66 9 Claims ABSTRACT OF THE DISCLOSURE An apparatus for sequentially folding and stacking individually received sheets of a flexible material to prepare counted stacks of the folded sheets for subsequent packaging. The illustrated embodiment of the apparatus includes means for conveying the individual sheets along a path of travel, first transverse folding means positioned intermediate the path of travel for folding each sheet upon itself along a transverse fold line, second transverse folding means positioned intermediate the path of travel and subsequent to the first folding means for imparting a second transverse fold, and longitudinal folding means adjacent the terminal end of the path of travel for imparting a longitudinal fold. The thus folded sheets are then delivered to a platform which sequences downwardly upon receiving each folded sheet such that the level at which the folded sheets are received on the platform remains substantially constant. When the platform reaches its lowest position a delivery belt is actuated to remove the stack of folded sheets from the platform and transport the same to a packaging station.

The present invention relates to an apparatus for automatically processing individual pieces of relatively limp sheet material such as lightweight blankets, towels, diapers and the like. More particularly, the apparatus is adapted to sequentially fold a plurality of flexible sheets along two perpendicular fold lines, and to pile the folded sheets in stacks containing a predetermined number.

In the manufacture of many textile products, it is conventional to cut individual articles from a continuous length of textile material, and to separately process each article, such as by stitching along the four edges. At the conclusion of the required manufacturing operations, the machine sequentially delivers the finished articles to a delivery table or the like, where the products are picked up and folded by hand and placed in separate stacks of a predetermined number suitable for final packaging. A machine of this general type is described in copending application, 'Ser. No. 853,255, filed Aug. 26, 1969, now US. Pat. No. 3,580,198, issued May 25, 1971, and which is assigned to the assignee of the present invention.

It will be readily appreciated that the efiiciency of automatic processing machines of the above type is severely limited by the required manual folding and stacking operations. In particular, these manual operations are too slow for high volume production, and are incapable of providing identically folded articles in a neat stack. In addition, the use of manual labor signiflcantly increases the cost of the process.

Accordingly, it is an object of the present invention to provide an apparatus for efficiently and automatically folding and stacking flexible sheets of the described type, and wherein the above noted disadvantages of the manual operations are eliminated.

It is a more particular object of the present invention to provide an apparatus which is adapted to automatically fold flexible sheets along at least one transverse fold line, as well as along a longitudinal fold line, and to prepare and deliver counted stacks of the folded sheets for packaging.

These and other objects and advantages of the present invention are achieved in the embodiment illustrated herein by the provision of an apparatus which includes conveyor means for conveying the individual sheets along a path of travel, and transverse folding means positioned intermediate the path of travel for sequentially folding each sheet along a transverse fold line. A longitudinally disposed rod is positioned adjacent the terminal end of the conveyor means and is programmed to lift each transversely folded sheet and fold the same along the longitudinal fold line formed by the rod. The rod then transports the folded sheets to a platform which is adapted to sequentially receive the sheets to form a vertical stack. The platform is designed to be lowered an increment approximately equal to the thickness of a folded sheet upon receipt of each sheet from the longitudinal rod, and to cooperate with a conveyor upon receiving a predetermined number of sheets for removal of the stack from the platform.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is a schematic illustration of the folding and stacking apparatus of the present invention;

FIG. 2 is a schematic illustration of the folding portion of the apparatus shown in FIG. 1, and particularly illustrating the drive arrangement for the various conveyor rollers;

FIG. 3 is a fragmentary side view, partly sectioned, of the one-way clutch for actuating the final delivery belts, and taken substantially along the line 3-3 of FIG. 1;

FIG. 4 is a top plan view of the transfer mechanism and stacking apparatus of the present invention;

FIG. 5 is a side view, partly sectioned, illustrating the details of the transfer mechanism;

FIG. 6 is a sectional view taken substantially along the line 6-6 of FIG. 4 and illustrating the platform at its elevated position;

FIG. 7 is a sectional view corresponding to the lefthand portion of FIG. 6 with the delivery belts being omitted for purposes of clarity;

FIG. 8 is an end view facing opposite the view in FIG. 7 and illustrating the platform at its lowered position;

FIG. 9 is a schematic illustration of the first and second transverse folding stations of the present invention;

FIG. 10 is a schematic diagram of the electrical control system for the transverse folding stations illustrated in FIG. 9;

FIG. 11 is a schematic wiring diagram for the longitudinal folding and transfer mechanism; and

FIG. 12 is a schematic wiring diagram for the platform indexing and the delivery belt actuating mechanisms.

Referring more specifically to the drawings, the overall features of the invention will first be described with reference to FIG. 1. In particular, the apparatus includes conveyor means 20 including an endless conveyor belt 21 for conveying individual sheets 22 of a flexible textile material or the like along a first path of travel defined by the belt 21 from an adjacent fabricating or treating apparatus (not shown) such as the one described in the above-identified copending application. First transverse folding means 24 is positioned along the first path of travel ahd beneath the discharge end of the belt 21, and is adapted to sequentially fold each sheet upon itself along a first transverse fold line.

Conveyor means 20 further includes a second endless conveyor belt 28 for conveying the transversely folded sheet from the folding means 24 along a second path of travel defined by the belt 28. Second transverse folding means 30 is disposed below the discharge end of the belt 28 and is adapted to again fold each sheet upon itself to impart a second transverse fold therein. A third endless conveyor belt 34 is provided for conveying the twice folding sheet from the second folding means 30 along a third path of travel defined by the belt 34 to a terminal end 35.

Means 40 is provided for longitudinally folding the individual sheets as they arrive at the end 35, and includes a longitudinally disposed rod 42 which is initially positioned below the terminal end 35. The rod 42 is sequentially actuated to lift each transversely folded sheet from the conveyor belt 34, to fold the same upon itself along a longitudinal fold line formed by the rod, and to transport the folded sheet transversely from the third path of travel and deposit the same onto the platform means 44 to form a stack thereon. Platform means 44 includes the platform 46, and means including the piston 48 and pneumatic cylinder 49 (FIG. 12) for vertically translating the platform 46 between an elevated and a lowered position. Delivery belts 50 are provided for removing a stack of a predetermined number of folded sheets from the platform 46 and delivering the same in condition for packagmg.

All of the above generally described features and the more specifically described features below are suitably mounted on a common interconnected frame 164. The frame 164 has been shown in part only in the drawing for simplicity of illustration and it is to be understood that this frame carries all of the elements of the apparatus of this invention.

To now describe the various features of the present invention more specifically, FIGS. 1 and 9 illustrate the conveyor means 20 which includes the horizontal endless belt 21 which is driven at a constant speed by a conventional motor (not shown). As shown in FIG. 1, the belt 21 is longitudinally split into two spaced segments such that a vertical beam of light may be passed therethrough for the purposes hereinafter stated. The belt 21 is disposed about the end roller 54 to define a discharge end such that the leading portion of the sheet 22 which is being fed along the upper surface of the belt will drape vertically downwardly into a position to be engaged by the first folding means 24 as seen in FIG. 1.

The first folding means 24 includes a conventional photoelectric proximity sensor 56 for detecting the presence or absence of a sheet on the belt 21. A transverse bar 58 is disposed below the discharge end of the belt 21 and is longitudinally translatable by a cam 60 and follower 62 such that the bar 58 is advanced longitudinally beyond the end of the belt 21 to engage a sheet at its approximate mid-portion when the sensor 56 detects the trailing edge of a sheet 22. A pair of cooperating

nip rollers

64 and 65 are aligned with the bar such that the advance of the bar will direct a sheet into the nip of the rollers. The rollers are rotated at a constant speed in opposite directions by an arrangement hereinafter described, such that the sheet will be drawn through the rollers and thus folded upon itself.

An upper endless conveyor belt 68 is disposed about the rollers 64 and 70, and immediately above the endless conveyor belt 28 which in turn is disposed about the

rollers

65 and 72. Viewing FIG. 2, it will be observed that the belts 28 and 68 are driven at corresponding speeds in opposite directions by a drive train which includes an electric motor 74, reduction gear box 75, main drive shaft 76, drive chain 77, idler shaft 78, drive chain 79, shaft 80 mounting roller 65, shaft 81 carrying gear 82, and shaft 83 carrying cooperating gear 84 and roller 70. The far end of shaft 83 mounts a drive chain 85 for rotating shaft 86 mounting roller 64. As will be apparent, the transversely folded sheet 22 passing through the nip

rollers

64 and 65 will be conveyed between the belts 28 and 68,

and the leading end thereof will subsequently pass over the roller 72 and drape vertically downwardly into a position to be engaged by the second folding means 30. As seen in FIG. 1, the belts 28 and 68 are also longitudinally slit into two spaced segments to permit observation of the sheets 22 from above.

The second folding means 30 includes a photoelectric proximity sensor 90 positioned to detect the presence or absence of a sheet being conveyed between the belts 28 and 68, and a transverse bar 92 disposed below the roller 72. The bar 92 is longitudinally translatable by the cam 94 and follower 95 in a manner similar to the advance of bar 58, and a pair of cooperating

niprollers

96 and 97 are aligned with the bar to receive and fold the sheet in a manner equivalent to that described above with respect to folding means 24.

The control arrangement for selectively longitudinally translating the transverse bar 58 of the first transverse folding means 24 includes a shaft 100 (FIG. 2) carrying an identically configured cam 60' on the far side of the belt 21. The shaft 100 is connected to the main drive shaft 76 through a brake 102 and clutch 104, and a drive chain 106. Thus when the brake 102 is disengaged and the clutch 104 engaged, shaft 100 will be rotated by the shaft 76, but when the brake is engaged and the clutch disengaged, the shaft 100 will remain stationary. The followers 62 and 62' associated with the cams 60 and 60' each comprise a longitudinally disposed rod mounting the bar 58 at the forward end thereof, and suitable guide blocks 109 serve to guide the follower rods in the longitudinal direction. Viewing FIG. 9 it will be observed that the cams 60 and 60' include an internal cam surface 111 for guiding the followers 62 and 62', and an external cam surface 112 controlling actuation of a switch 114.

The second folding means 30 includes a similar control arrangement which includes earns 94 and 94 carried by shaft 116 on opposite sides of the belt 28, with the shaft 116 being connected to the main drive shaft 76 through a brake 118, clutch 119, and drive chain 120. The followers 95 and 95' include longitudinal rods which in turn mount the bar 92, and the cams 94 and 94' include an internal cam surface 124 for guiding the followers 95 and 95', and an external cam surface 125 for controlling actuation of a switch 126.

A suitable electrical circuit for selectively actuating the first and second folding means 24 and 30 is illustrated schematically in FIG. 10. The circuit is of a conventional design we'll known to those skilled in the art, and includes a photoelectric relay 128, such as Model TR4-3 manufactured by Farmer Electric Products Company, Inc. of Natic k, Mass., which is associated with the sensor 56 and is adapted to latch in its relay upon a signal from the sensor indicating that the trailing edge of the sheet 22 is passing beneath it on the belt 21. The brake 10-2 is thereby released and clutch 104 engaged to cause the shaft 100 to rotate clockwise as seen in FIG. 10. The shaft rotates until the raised portion of the cam 60 trips switch 114 to drop out the relay 128. The cam then coasts until switch 114 drops off the raised portion to engage the brake 102, wherein the system is ready-for the next cycle.

A similar photoelectric relay is associated with the sensor 90 of the second folding means 30. -In this case however, a timer 131, such as model 120T manufactured by Farmer Electric, is positioned to trip the relay 130 a preselected time interval after the sensor 90 detects the trailing edge of the folded sheet. The relay acts to rotate the shaft 116 of cam 94 and trip the switch 126 in a manner similar to that described above with reference to the first folding means 24. In addition, a pair of manual override switches 132 and 133 are provided for each of the folding means to permit manual resetting of the associated relay circuits.

After the sheets 22 are twice folded in the manner described above, they are conveyed along the upper surface of belt 34 to the terminal end at 35. The belt 34 is disposed about the lower nip roller 97 and a terminal roller 136, and it will be seen that the belt is longitudinally split into two spaced segments for the purposes to become apparent. The belt 34 cooperates with an overlying belt 138 disposed between the upper nip rollers 96 and roller 139, and the two belts are connected to the main drive shaft 76 by an arrangement including the clutch 140, and

drive chains

142 and 143 connecting shaft 144. The shaft 144 extends through the belt 34, and carries drive chains 145 and 146 on the far side as seen in FIG. 2 for rotating shafts 147 and 148 respectively carrying

rollers

97 and 136, and it will be seen that the belt is longitudinally split which mates with the gear 150 of shaft 152 to turn the roller 139. The far end of shaft 152 carries a drive chain 154 interconnecting the shaft 156 which mounts nip roller 96. A brake 158 is mounted on shaft 148 such that when the brake is engaged and the clutch 140 disengaged, the

belts

34 and 138 may be held stationary, and when the brake is disengaged and the clutch engaged, the two belts are rotated at corresponding speeds. A switch 160 is positioned below the terminal end 35 of the conveyor means 20 as seen in FIG. 1, with the switch including an upwardly directed actuating arm 161 extending through the opening between the belt segments so as to be contacted by a folded sheet being conveyed along the belt 34.

The longitudinal folding means 40 includes a frame 164- positioned adjacent the terminal end 35, with the frame mounting a carrier 165 which is longitudinally translatable along the rods 166 and 167. The carrier is translated by movement of the piston 168 in the pneumatic cylinder 169 which is secured to the frame, with the piston being connected to the carrier by the cord and pulley arrangement 170 as seen in FIG. 1. Thus, when the piston 168 is translated in one direction, the carrier 165 is translated in the opposite direction.

The carrier 165 includes a longitudinal shaft 172 rotatably mounting a gear 174 and interconnected lever arm 175. A side arm 176 on the carrier mounts a pneumatic cylinder 178 having a piston 179 (FIG. 11), and a gear rack 180 is connected to the piston and translatable therewith. The rack 180 operatively engages the gear 174, and thus movement of the piston 179 in the cylinder 178 will cause the rack to be translated and the gear 174 and lever arm 175 to rotate through the are indicated in dashed lines in FIG. 1. The remote end of the lever arm 175 mounts the rod 42 which is initially positioned to extend longitudinally into the opening between the segments of the belt 34, but somewhat beneath the upper surface thereof. It should also be noted that two

switches

182 and 183 are carried by the frame 164 adjacent the periphery of the gear 174, with the gear 174 including an actuating arm 184 positioned to actuate the switch 182 approximately midway through the arcuate translation of the rod 42. The switch 183 is actuated by the arm 184 when the rod 42 reaches its terminal position adjacent the platform means 44. In addition, three switches numbered 185, 186, and 187 are carried by the frame in position to be contacted by the carrier 165 as it is translated rearwardly along the rods 166 and 167. The function of these switches will be further explained below.

As seen in FIGS. 4 and 5, the rod 42 is hollow and includes a plurality of radially directed openings 189. A vacuum line 190 extends along the length of the lever arm 175 and communicates with the hollow rod such that the vacuum, in the line 190 evacuates the hollow core of the rod and causes air to be drawn inwardly through the radial openings for the purposes hereinafter described. A conven tional vacuum transducer 192 which converts air pressure to vacuum is used to control the flow of air through the line 190.

A suitable electrical control arrangement for actuating the above-described longitudinal folding means 40 is illustrated schematically in FIG. 11. As will be apparent from a study of this illustration, the arrival of a folded sheet 2 2 at the terminal end 35 actuates the switch 160 which in turn closes the solenoids 195 and 196. Solenoid 195 closes the solenoid 198 and also controls the timer 200 which is designed to shut down the apparatus if a jam up or stoppage occurs. More particularly, if the switch stays closed longer than a preselected interval set on the timer 200, the power is cut to the holding coil 205 which stops the motor 74 and thus the entire apparatus. Corrective ac tion is then necessary to restart the machine. Solenoid 198 actuates the counter 201 and turns on the air valve 203 connecting pressure source 202 to the transducer 192, and also actuates the solenoid 204. The closing of solenoid 196 opens the line to the solenoid 206 of the carriage pneumatic valve 207, and engages the brake 158 and disengages the clutch 140 to thereby terminate movement of the

belts

34 and 138.

The closing of solenoid 204 actuates the solenoid 208 of the pneumatic valve 210 which directs the pneumatic pressure into the cylinder 178 to translate the piston 179 toward the left as seen in FIG. 11. This in turn draws the rack 180 across the gear 174 to arcuately translate the lever arm 175 and rod 42. During movement of the lever arm and rod, the switch 182 is opened to release the holding circuit to solenoid 195. When the arm reaches its terminal point, the switch 183 moves from contact 211 to contact 212 to release the holding circuit to solenoid 198 and thereby turn off the air passing through the valve 203. Closing contact 212 actuates the solenoid 213 which in turn actuates solenoid 214 controlling the pneumatic valve 207 connected to cylinder 169. This in turn causes the carrier to be translated rearwardly or toward the right as seen schematically in FIG. 11, and upon reaching its most rearward position, the switch 185 is closed and switches 186 and 187 are opened. Switch 186 releases solenoid 204 to thereby close solenoid 215 and rotate the lever arm through a reverse arc. The opening of switch 187 releases the solenoid 2113 to return the carrier to its original position by actuating solenoid 206. The closing of normally open switch controls the movement of the platform means 44 as hereinafter described. To complete the description of the circuit shown in FIG. 11, it will be noted that there is a manual restart switch 216 and an off-on switch 217.

The structural details of the platform means 44 for receiving the folded sheets are best illustrated in FIGS. 6-8 and 12. Generally, the platform means includes the platform 46 which is adapted to receive and support the folded sheets 22. The platform is in turn supported by the vertically translatable support rod 218 which is connected to the piston 48 in the cylinder 49. The cylinder 49 is operatively connected through the valve 220 to the pressure source 202 such that upon opening the valve 220 the platform is lifted to its elevated position.

Means are further provided for sequentially lowering the platform from its elevated position to its lowered position such that the platform is lowered an increment approximately equal to the thickness of a folded sheet upon receipt of each sheet to thereby form a vertical stack of sheets on the platform having a consistent elevation approximately equal to that of the platform at its elevated position. To accomplish this purpose, a pair of oppositely directed

racks

221 and 222 are secured to the support rod 218, with each of the racks mounting nine vertically spaced

teeth

223 and 224 respectively. It will be noted that the teeth on the two racks are vertically olfset from each other such that the teeth on one rack are positioned at a level intermediate the teeth on the opposite rack.

A double pole switch 226 is mounted adjacent the rack 222 and includes an actuating arm 227 which is adapted to ride along the teeth 224. A second double pole switch 230 is positioned adjacent the rack 221, and includes a similar actuating arm 231. As will be apparent from FIGS. 6-8, the

switches

226 and 230 will close one pole when the arm is laterally lifted by one of the teeth, and will close the opposite pole when the lever arm is positioned intermediate two teeth. By design, these two switches will be actuated in an alternate fashion.

A pair of pneumatically actuated slide arms 234 and 235 are also mounted adjacent the two racks with the slide arm 234 adapted to be translated into operative engagement with one of the teeth 224, and the slide arm 235 adapted to operatively engage one of the teeth 223. The two slide arms 234 and 235 are controlled by the valves 238 and 239 respectively, and it will be observed in FIG. 12 that both of the arms are spring-biased in a direction away from the racks such that they will engage the associated teeth only when the valve is connected to the pressure source 202.

The illustrated apparatus further includes means for removing the stack of folded sheets from the platform 46 upon the platform reaching its lowered position. In this regard, it will be noted that the platform includes a number of spaced parallel slots 242 extending in a longitudinal direction through the platform, note FIG. 4. A plurality of spaced parallel conveyor belts 50 are positioned below the platform at an elevation slightly above that of the platform at its lowered position with each of the belts 50 adapted to communicate with one of the platform slots 242. Thus as the platform reaches its lowered position, the stack of sheets 22 positioned thereon will be substantially supported by the belts 50.

The belts 50 are selectively actuated upon the platform reaching its lowered position to withdraw the stack of sheets therefrom in the manner best illustrated in FIG. 1. For this purpose, a pneumatic cylinder 244 is mounted adjacent the delivery belts 50 and includes a following rack 246 which engages the one-way clutch 248, shown in detail in FIG. 3. The rack further carries an actuating arm 259 adapted to contact switch 260 when in its withdrawn position, and to contact switch 261 when in its extended position.

The clutch 248 is carried by the shaft 250 for actuating the sprocket and drive chain 252. The drive chain 252 is in turn connected to the shafts 253 and 254 which carry a forward roller 256 and a rear roller 257 respectively. As best seen in FIG. 1, actuation of the pneumatic cylinder 244 causes the rack 246 to translate toward the right, which in turn acts through the clutch 248 to rotate the

rollers

256 and 257 and thus the delivery belts 50. When the rack 246 wthdraws to its original position, the clutch 248 serves to prevent reverse rotation of these members.

The operation of the platform means 44 will be more fully understood by reference to the exemplary circuit illustrated in FIG. 12. The circuit includes switch 185 which, as explained above, is closed when the carrier 165 is withdrawn to its rearward position. The closing of switch 185 directs current through

switches

226 and 230 to the solenoids 265 and 266 which respectively advances the slide arm 234 into engagement with the teeth 224 and withdraws the slide arm 235 from the teeth 223. Thus the rod 218 is dropped a distance equal to one-half the spacing between the adjacent teeth on the racks. Upon the next closing of the switch 185, the

switches

226 and 230 will be positioned on the opposite poles as shown in FIG. 12 by reason of the fact that the rod 218 has dropped an increment equal to one-half the distance between adjacent teeth. Thus the solenoids 268 and 269 will be actuated, and the side arms will return to their original positions. This causes the rod 218 to drop a second increment.

The above operation continues until the racks reach the position shown in FIG. 8 wherein the platform 46 is ready to receive the last folded sheet. In this configuration, the followers 227 and 231 are both above the last tooth of the associated rack, and thus when the last sheet is received the subsequent electrical impulse will retract both slides 234 and 235 and the racks will drop to permit the arm 273 to close switch 272. Closing switch 272 directs current through the normally closed switch 260 to solenoid 275, which in turn closes solenoid 277 controlling the valve 278 to cylinder 244. The switch 260 is opened upon movement of the arm 259 on rack 246, but the solenoid 275 remains closed by reason of the holding circuit through switch 261. When the rack 246 reaches its outer limit, pole 280 of switch 261 is opened to release the holding circuit to solenoid 275 and thus permit the return of the rack. Simultaneously, the pole 281 of switch 261 is closed to actuate the solenoid 282. This in turn closes the solenoid 284 which opens the valve 20 to lift the platform upwardly to its elevated position. When the elevated position is reached, the lower pole 287 of switch 288 opens to release the solenoid 282, and the upper pole 289 is closed to energize the solenoid 269 to slide in the arm 235 under the lowest tooth on rack 221. A manual override switch is provided at 290 to re-set the stacker when desired.

It is believed that the overall operation of the apparatus will be apparent from the above detailed description. To briefly summarize its operation however, the flexible sheets to be folded and stacked are individually positioned on the belt 21 and conveyed along the upper surface thereof until the leading edge of the sheet is draped over the end defined by the roller 54. By design, the sensor 56 is positioned to sense the trailing edge of the sheet when the mid-portion thereof is opposite the transverse bar 58. Thus, translation of the bar 58 causes the mid-portion 0f the sheet to be inserted between the oppositely rotating nip

rollers

64 and 65. The folded sheet is then conveyed along the belt 28 and the folding process is repeated by the second folding means 30. In this case however, the sensor is positioned to sense the trailing edge prior to the mid-portion reaching the bar 92, with the timer 131 (FIG. 10) being programmed to delay actuation of the bar until the mid-portion is reached.

As the twice folded sheets approach the terminal end 35 of conveyor means 20, the switch is closed. This actuates the circuit shown in FIG. 11, and results in the rod 42, which is initially positioned .below the terminal end, to be translated through a first are extending to a second position immediately overlying the platform 46. Concurrently, air valve 203 will be opened to actuate the transducer 192 and create a vacuum in rod 42 to thereby facilitate the accurate folding of the sheet on the rod. The vacuum is released by switch 182.as the sheet is being placed on the platform 46. When the rod is longitudinally withdrawn from its position over the platform, the rod is translated through a reverse are which is substantially equivalent to the first arc. Finally, the rod is longitudinally advanced to its original position immediately beneath the terminal end 35. Thus the rod 42 will be seen to lift each transversely folded sheet from the conveyor 34, fold the same along the longitudinal fold line formed by the rod, and transport the folded sheet away from the terminal end 35 and onto the platform 46.

As each sheet is deposited on the platform 46, the platform will be lowered a distance equal to one-half the spacing between the teeth on the

racks

222 and 221, which by design will be approximately equal to the thickness of the folded sheet. Thus each sheet will be deposited at approximately the same elevation. When the desired number of sheets has been received, the platform will drop to its lowered position such that the sheets are substantially resting on the belts 50 which extend through the slots 242 in the platform 46. The belts 50 are then actuated to withdraw the sheets from the platform to a position where they may be removed for subsequent packaging. The platform 46 then returns to its elevated position and is ready to receive the next sheet. Thus the entire operation of the machine is automatic and continuous, and no manual attention is required.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

What is claimed is:

1. An apparatus for sequentially folding and stacking a plurality of flexible sheets comprising frame means,

conveyor means carried by said frame means for conveying individual sheets along a path of travel to a terminal end thereof,

transverse folding means carried by said frame means and positioned intermediate the length of said couveyor means for sequentially folding each sheet upon itself along a transverse fold line as the sheet is conveyed by said conveyor means,

longitudinal folding means carried by said frame means and positioned adjacent the terminal end of said conveyor means and including a longitudinally disposed rod for lifting each transversely folded sheet from said conveyor means, for folding the same along a longitudinal fold line formed by said rod, and for transporting the folded sheet away from said conveyor means, and

platform means carried by said frame means and positioned adjacent said longitudinal folding means for sequentially receiving the folded sheets from said longitudinal folding means to form a vertical stack thereof.

2. The apparatus as defined in claim 1 wherein said platform means includes a horizontal platform, and means for vertically translating said platform between an elevated position and a lowered position and including means for lowering said platform an increment approximately equal to the thickness of a folded sheet upon receipt of each sheet from said longitudinal folding means to thereby form a vertical stack of folded sheets on said platform having a consistent elevation approximately equal to that of the platform at its elevated position.

3. The apparatus as defined in claim 2 further including means for removing the stack of folded sheets from said platform upon said platform reaching its lowered position.

4. The apparatus as defined in claim 3 wherein said means for removing the stack of folded sheets includes spaced parallel slots extending through and defined by said platform, a plurality of spaced parallel conveyor belts positioned generally below said platform at an elevation slightly above that of the platform at its lowered position with each of said belts adapted to communicate with one of said platform slots, and means for selectively actuating said conveyor belts upon said platform reaching its lowered position to withdraw the stacked sheets therefrom.

5. The apparatus as defined in claim 2 wherein said longitudinal folding means further includes means for sequentially translating said rod through a first are extending from a first position below the terminal end of said conveyor means to a second position adjacent said platform, for longitudinally withdrawing said rod from said second position, for translating said rod through a reverse are equivalent to said first arc, and for longitudinally advancing said first rod to said first position.

6. The apparatus as defined in claim 5 wherein said rod includes vacuum means for facilitating accurate folding of the sheet on the rod.

7. The apparatus as defined in claim 1 wherein said conveyor means includes a horizontal endless belt defining a discharge end, and said transverse folding means includes a transverse bar mounted immediately below said discharge end of said endless belt,

a cooperating pair of nip rollers longitudinally aligned 10 with said transverse bar and also forming a part of said conveyor means,

means for rotating said nip rollers in opposite directions, and means for selectively longitudinally translating said transverse bar to closely approach said nip rollers whereby a sheet having ends and dropping vertically downwardly from said discharge end may be engaged intermediate its ends by said transverse bar and drawn between said nip rollers to fold the same therebetween. 8. The apparatus as defined in claim 7 wherein said means for selectively longitudinally translating said tran verse bar includes a photoelectric proximity sensor positioned to sense the presence or absence of ,a sheet on said endless belt and rotatable cam means operatively controlled by said sensor for advancing and retracting said transverse bar.

9. An apparatus for sequentially folding and stacking a plurality of flexible sheets comprising frame means, conveyor means carried by said frame means for conveying individual sheets along a path of travel to a terminal end thereof,

first transverse folding means carried by said frame means and positioned intermediate the length of said conveyor means for sequentially folding each sheet upon itself along a first transverse fold line as the sheet is conveyed by said conveyor means, second transverse folding means carried by said frame means and positioned intermediate the length of said conveyor means and subsequent to said first trans verse folding means for sequentially folding each sheet upon itself along a second transverse fold line as the sheet is conveyed by said conveyor means,

longitudinal folding means carried by said frame means and positioned adjacent the terminal end of said conveyor means and including a longitudinally disposed rod for lifting each transversely folded sheet from said conveyor means, for folding the same upon itself along a longitudinal fold line formed by said rod, and for transporting the folded sheet transyersely from said conveyor means, and

References Cited UNITED STATES PATENTS 1,673,064 6/1928 Dexter 270-62 2,054,426 9/1936 Kahn 270-83 2,145,592 1/ 1939 Folger 270-83 2,942,874 6/1960 Hajos 270-83 3,190,640 6/1965 Sjostrom 270-66 3,260,518 7/1966 Kamberg et a1 270-62 3,361,424 1/1968 Kamberg 270-66 3,363,897 1/ 1968 Northern et al. 270-84 3,602,494 8/ 1971 Holmes 270-31 FOREIGN PATENTS 1,093,691 12/1967 Great Britain.

RUSSELL R. KINSEY, Primary Examiner US. Cl. X.R. 270-86 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 702, 696 Dated November 14, 1972 lnventofls) I Richard K. Teed It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 12, and it will be seen that the belt is longitudinally split" should be A gear 149 is mounted on the near end of shaft 144 Column 8, line 9, "20" should be 220 Signed and sealed this 13th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1050 (10-69] USCOMM DC 6o375 p69 u.s. GOVERNMENT r-mm'mc OFFICE 1969 O366'H4