US2732204A

US2732204A - Sheet stack feeding mechanism

Info

Publication number: US2732204A
Authority: US
Publication date: 1956-01-24
Anticipated expiration: 1973-01-24

Description

Jan. 24, 1956 L- C. PEARCE SHEET STACK FEEDING MECHANISM l2 Sheets-Sheet 1 Original Filed 001;. 10, 1950 laws 61 1 6/7266 flffUQ/VEf-(S' L INVENTOR.

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Jan. 24, 1956 L. c. PEARCE 2,732,204

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SHEET STACK FEEDING MECHANISM Original Filed Oct. 10} 1950 12 Sheets-Sheet '7 INVENTOR. 3 laws 6! PEQQCE Jan. 24, 1956 L. c. PEARCE 2,732,204

SHEET STACK FEEDING MECHANISM Original Filed Oct. 10, 1950 12 Sheets-Sheet 8 INVENTOR. [540/5 62 1059966 WWW Jan. 24, 1956 L. C. PEARCE 2,732,204

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\ SHEET STACK FEEDING MECHANISM Original Filed Oct. 10, 1950 12 Sheets-Sheet 12 INVENTOR. (sea/s C. 1 6/7866 United States Patent SHEET STACK FEEDING MECHANISM Lewis C. Pearce, Berea, Ohio, assignor to Pearce Development Company, Cleveland, Ohio, a corporation Original application October 10, 1950, Serial No. 189,362,

now Patent No. 2,589,428, dated March 18, 1952. Divided and this application January 11, 1952, Serial No. 266,074

'7 Claims. (Cl. 271-62) This invention relates to a sheet stack feeding mechanism and particularly to a sheet stackfeeding mechanism especially adapted for but not limited to incorporation in a collating machine. The present application is a division of my copending application for Collating Machine, Serial No. 189,362, filed October 10, 1950, now Patent No. 2,589,428, which is directed toward, the collating machine as a whole.

A main object of the present invention is to provide a sheet stack feeding mechanism by which a stack of sheets can be automatically elevated during a collating operation to maintain the top of the stack at a substantially constant level to provide a supply of sheets for a sheet removal mechanism.

Another object of the present invention is to provide a sheet stack feeding mechanism as above described in which there is a mechanism for successively removing sheets from the stack, another mechanism for raising the stack of sheets at a rate greater than that at which the sheets are removed, and a third mechanism responsive to movement of thesheet removing mechanism for intermittently interrupting operation of the sheet raising mechanism to maintain the top of the stack at a substantially constant level.

A further object of the present invention is to provide a sheet stack feeding mechanism as above described, in which the raising mechanism is inactivated whenever'the top of the stack rises beyond a predetermined level or drops below a second and lower predetermined level.

A still further object of the present invention is to provide a sheet feeding mechanism including two sheet stack elevators arranged to be alternately automatically driven and to by-pass one another enabling a stack of sheets to be replenished. t

An additional object of the present invention is to provide a sheet feeding mechanism as described in the immediately-above paragraph in which there are manually controlled means for operating the inactivated elevator to enable it to be lowered and raised relative to the active elevator, and in whichthere is a mechanism for positively preventing operation of the manually controlled means in the direction which would cause movement of the elevators in opposition to that caused by the automatic mechanism.

Various other objects of the present invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

Fig. l is a schematic view in side elevation showing a four station collating machine, at which stations are located the stacked supply of papers or paper sheets to be fed upwardly and collated, Fig. 1 graphically illustrating the manner of collating the sheets by the machine.

Fig. 2 is afragmentary view in perspective showing the main drive mechanism of the machine and the manner of its connection with the cam shaft of the machine.

Fig. 3 is a view in side elevation of the machine with a part thereof broken away showing thatside of the machine which is opposite the cam shaft side, which will be 2,732,204 Patented Jan. 24, 1956 termed hereinafter as the work side of the machine as distinguished from the cam shaft or gear side of the machine.

Fig. 4 is an enlarged fragmentary view in section showing the manner of closing the signaling circuit and opening the main motorfdrive circuit if a jam occurs at the top of a stack of sheets.

Fig. 5 is a fragmentary view illustrating the sheet pick up and transfer mechanism.

Fig. 6 is a diagrammatic view .showing the paper height ice , sensing means and the electric circuit in conjunction therewith.

Fig. 7 is a fragmentary view in transverse section disclosing the rack for raising the stacks of sheets and also showing certain features of a vacuum and air pressure control for the pick up and transfer mechanism.

Fig. 8 is a fragmentary. view of the same mechanism partly in section and taken at right angles to the view in Fig. 7, the section being taken along line 8-8 of Fig. 7.

Fig. 9 is a fragmentary view in vertical transverse section through the machine taken along line 9-9 of Fig. 3.

Fig. 10 is a view in transverse section taken at an elevation just below that illustrated in Fig. 9 and taken on line 10-10 of Fig. 3.

Fig. 11 is a schematic and diagrammatic view illustrating the stack feeding, elevating and drive mechanisms, both manual and automatic.

Fig. 12 is a fragmentary view in side elevation taken at one station of the machine and showing certain features of the drive mechanism for feeding and elevating the stacks.

Fig. 13 is a fragmentary view in section through certain of the gear and clutch mechanisms incorporated in the stack feeding and elevating drive.

Fig. 14 is a view in transverse section through the clutch mechanism incorporated in the drive of the stack feeding and elevating mechanism, and taken on line 14-14 of Fig. 13. I

v Fig. 15 is a view in transverse sectionwith parts thereof broken away to show the one-way clutch mechanism illustrated in Fig. 13, and is taken on line 15-15 of Fig. 13.

Fig. 16 is an exploded view in perspective illustrating a portion of the control mechanism for opening motor circuits at the upper and lower ends of the travel of the elevators.

Fig. 17 is a fragmentary view in plan section taken on line 17-17 of Fig. 12.

Fig. 18 is an electrical. diagram showing the arrangement for inactivating or de-energizing the main motor upon jamming-or other conditions in the machine.

The collating machine in which my invention is incorporated contemplates the provision of a plurality of stations at each of which-is located a stacked supply of pages or paper sheets to be collated. These stations are labeled in Fig. 1 of the drawings as stations numbers 1, 2, 3 and 4. In the present instance I have illustrated the machine as including four of such stations, but it is to be understood, however, that this number may be such as desired andmay be greater or less than four. Regardless of the-number of the stations, the machine, except for length, remains the same in'the principal aspects of 1 its construction and mode of operation.

Overlying the stack feedingmechanisms and the stacks of paper sheets therein and extending longitudinally of the machine in proper vertical register with the stacks of paper sheets at the stations 1, 2, 3 and 4 is a gripper carrier indicated in Fig. 1 by the numeral 5. This gripper carrier includes two endless sprocket chains 6 disposed in a vertical plane and in parallelism at a spaced distance apart, as illustrated in Pig. 2 of the drawings.

By reference to this figure, it will be seen that the endless chains 6 are each arranged at the interior sides of side frame members 7 which form a fixed part of the structural rigid frame of the machine. The endless chains 6 of the carrier engage sprockets 8 fixed on a transverse horizontal drive shaft 9 suitably journaled in the frame members 7. This drive shaft 9 is fitted with a fixed pulley 10 connected by V-belts 11 toa drive pulley 12 on a motor driven shaft 14. Obviously, the drive shaft 14 may be driven to result in the proper speed for the machine, which speed will depend to some measure upon its size, the product being handled and the output or capacity desired.

Also driven from the shaft 9 through a gear train, ineluding spur gears 15, an idler shaft 16, miter gears 17 and spur gears 18, is a first cam shaft 19 and a second cam shaft 20. These cam shafts are suitably journalled on the structural frame A of the machine, of which the frame members 7 heretofore referred to are an integral part.

It should be stated that the driving of the machine is located at the delivery end of the machine as illustrated in Fig. 3 of the drawings.

At the end of the machine opposite its drive end there is a horizontal transverse idler shaft 9a which is in horizontal alignment with the shaft 9 with its axis in parallelism therewith. The idler shaft 9a is fitted with sprockets complementary to the sprocketss on the shaft 9 and are similarly engaged with the endless sprocket chains 6 for obvious reasons.

Through the medium of the mechanism heretofore described, when the drive shaft 14 is placed in operation, the chains 6 of the gripper carrier 5 will be driven at the same desired speed in the same direction, and the direction of the drive is such that the bottom flights of the endless chains 6 will travel toward the delivery end of the machine, as illustrated in Fig. 1.

The gripper carrier 5 also includes a plurality of sets of sheet or page grippers B to K, inclusive, as shown in Fig. 1. Each set comprises a number of grippers corresponding to the number of stations 1 to 4, to-wit 4. The number of sets B to K of grippers and the relative spacing thereof on the carrier 5 is such as to enable continuous operation of the carrier mechanism ata constant speed. The spacing of the sets B to K, inclusive, on the gripper carrier 5 and the synchronous operation of the grippers thereof is such as to enable the top sheet on each of the four stacks to be removed during one cycle of operation of the auxiliary mechanism and each by one of the grippers of four different successive sets of the gripper members.

The synchronous drive of the gripper carrier and the page or paper sheet conditioning mechanism associated with the grippers (all operated in synchronism by the cam shafts) is such that there is a sufficient time interval permitted between successive gripping operations at each station to enable the sheet conditioning mechanism thereat to properly condition a sheet for gripping. It should be pointed out that the operation of the grippers in gripping a sheet and the. operation of the sheet conditioning mechanism essential to present and position a sheet for gripping at each station, requires one revolution of the cam shafts, and that is what has been meant heretofore by the term cycle of operation of the cam shafts.

When each set of grippers moves from the station 4 to the delivery endof the machine, it has gripped and collated sheets from the four stations in superimposed shingled relationship, as is illustrated in Fig. 1, and as the grippers pass a releasing station (which is just prior to the point at which the straight line bottom flight of the chains terminates and the chains commence to climb on the sprockets), the grippers are automatically opened by a stationary cam 21 to release the sheets. At this time the sheets overlie a moving conveyor 22, the upper flight of which is traveling in the same direction and at approximately the same speed as the lower flight of the chains 6, so that the collated set of superposed sheets delivered by the grippers will deposit upon the conveyor 22 in approximately the same shingled relationship that they were assembled in by the gripper sets. From this point the sheets may be glued and padded and other operations may be performed thereon such as desired, it being the ultimate purpose of the present machine to collate sheets from the four stations and deliver them in collated condition to the conveyor 22 in shingled or padded relationship as described.

At each station, there is a pick-up and transfer mechanism for picking up sheets from the stack and positioning them for gripping by the grippers. Referring to Figs. 3 and 5, it can be seen that there are fixed frame members 55 and 57 pivotally supporting pick-up arms 61 operable to pick up sheets by being pivoted toward and away from the sheets and by being connected to a source of vacuum through a tubular shaft 67 connected by a hose to a control valve 72 which is in turn connected by a conduit 73 to a manifold 116, which is connected to a source of vacuum (see Figs. 7 and 8). Pick-up arm 61 has a nozzle 68 adapted to engage the upper surface of the sheets on the stack. Valve 72 is adapted to be opened at proper intervals by a cam 74 (see Fig. 8) provided on cam shaft 20. To separate the sheets during the picking up operation, an air blast separating mechanism generally entitled 76 (see Fig. 5) is provided and is connected to a source of air under pressure through a valve which is connected by a conduit 87 to an air pressure manifold 117. Valve 85 is adapted to be actuated by a cam 84 fixed to cam shaft 20.

There is a second nozzle entitled 88 which is a transfer nozzle and which is adapted to further raise or lift the topmost sheet to a position where it can be gripped. Nozzle 88 is adapted to be connected to a source of vacuum by a conduit (not shown) connected to a valve (see Figs. 7 and 8), which is connected to vacuum manifold 116 by a conduit 101. Valve 100 is adapted to be controlled by a cam 102 provided on cam shaft 20. The timing of the operations of the valves disclosed in Figs. 7 and 8 is such that after the nozzle 68 has picked up a sheet, vacuum is supplied to the transfer nozzle and thereafter nozzle 68 is cut off from the source of vacuum while the transfer nozzle remains connected to the source of vacuum. During the transfer operation a blast of air is supplied to the separating mechanism to force all sheets except the topmost sheet back toward the stack. The construction and operation of this pickup and transfer mechanism is fully set out in the copcnding application previously identified.

In order to enable any station to be shut down. a valve 118 (see Fig. 7) is provided in the vacuum line and adapted to be operated by a shaft 119 (see Fig. 9) having a handle 120 by which it may be operated. The shaft 119 carries a bevel gear 121 meshing with a bevel gear 123 driving a shaft 122 connected to valve 118 through a gear 124 (compare Figs. 7 and 9).

As previously pointed out, each station is provided with a mechanism for receiving stacks of paper and for feeding that paper stack vertically in synchronism with the operation of the other mechanism of the machine in order to maintain the top sheet of the stack in proper position relative to the pick-up, sheet spreading and sheet transfer mechanisms of that station. This is in order that the topmost sheet may be picked up and conditioned to be grasped by the grippers as they come into operation in proper synchronism with those. mechanisms. Naturally. if the top of the stack isv properly relatively positioned with respect to those mechanisms, it will be properly positioned with respect to the gripper mechanisms.

Inasmuch as the stack receiving means at each station is identical and inasmuch as the stack feeding and elevating mechanism is precisely alike, but one will be described.

Reference being had to the drawings, particularly to Figs. 3, l2 and 17, it will be there seen that at each station there is provided a pair of rigid side frame bars 130 and 131 defining the front and back ends of the magazine within which is contained the paper stacks. The frame bar 130 is stationarily fixed to the frame of the machine, while the frame bar 131 is pivoted at its upper end as at 132 to the frame of the machine, and detachably connected at its lower end as at 133 to the frame of the machine. The detachable connection enables the lower end of the frame bar 131 to be adjusted longitudinally of the machine, as illustrated in Figs. 12 and 13. The reason for this adjustment will be explained hereinafter, but, in general, the purpose thereof is to accommodate stacks of paper sheets which may be thicker at one end, for any reason such as a folded condition, than the other. It is desired to point out that the frame bars 130 and 131 are at an inclination relative to the vertical, although they are in parallelism with respect to each other, except when adjustment is made for the purposes just described. The purpose of the inclination is to maintain the elevator platforms 134 at a slight angle to the horizontal so that the paper stack will by gravity seek to maintain the forward edges of the paper in the stack in exact register against vertical guide bars 135 arranged vertically of the frame at spaced intervals between the sides of the frame, or between the frame bar 130 and a back gage grid 136. This latter is adjustably supported at the side of the machine opposite the frame bars 130 and 131 in parallelism with the sides of the machine. By adjusting this gage grid 136 transversely of the machine, the machine may be used to accommodate paper sheets of varying widths. The vertical guide bars 135 are rigid with respect to the frame of the machine and present a plane gaging surface against which the edges of the paper of the stack may bear to maintain the sheets in proper register.

Thus, hereinafter when referring to the elevator platforms 134 as being horizontal, it will he meant that they are substantially horizontal but tilted at an angle to the horizontal, and when it is referred to the vertical movement thereof, will be meant substantially vertical but actually in a direction slightly inclined to the vertical.

Thus, it will be seen that the framebars 130, 131, the guide bars 135, and the gage grid 136 constitute a magazine in which the paper stacks are contained. It should be pointed out that there are two elevator platforms 134 at each station in each magazine for vertical movement with respect thereto. It should also be pointed out that there is a separate drive mechanism for raising and lowering the elevator platforms 134within the magazine for a purpose and in a manner which will be described. Actually, each platform 134 is removably insertable into the magazine and is removably supported upon feed nuts adjacent their four corners, by means of which they are elevated and lowered in the magazine. This is to enable a stack of paper to be inserted into the magazine and stacked on the platform. 7 Likewise, as will be hereafter pointed out, it is intended that as the uppermost elevator platform 134 is fed upwardly automatically when the machine is in operation, the lower elevator platform 134 may be lowered, charged with paper sheets and independently elevated at a relatively high rate of speed until it abuts against the bottom of the upper stack so as to maintain the stack supply of paper sufiicient at-all times to keep the machine in continuous operation.

When the upper end of the lower portion of the stack is elevated up to abutment with the lower end of the upper portion of the stack in a magazine, the thin elevator platform 134 interposed therebetween may be pulled 6 out, thus replenishing the stack without interrupting the operation of the machine.

There is a driving mechanism for the elevator and feed mechanisms of each magazine at each station, and that mechanism is more clearly disclosed in Figs. 9 and 10. Reference being had to these figures, it will be seen that each magazine is provided with two sets of feed screws 137 and 138, four to each set, vertically arranged in parallelism with the gage bars at the forward and rear ends of the magazine, but, as illustrated in Fig. 17, offset slightly with respect to the guide bars 135 in order that they will not contact the paper. Each set of these feed screws is arranged in two pairs, one pair at each end of the magazine. There is a pair of feed shafts 137 at each end of the magazine and a pair of feed shafts 138 at each end of the magazine.

Between the feed shafts 137 and 138 of each pair is a key bar 139. On each feed shaft is a non-rotatable feed nut 140, which feed nuts so engage the key bars 139 as to render said feed nutsnon-rotatable but enable them to travel longitudinally with relation to the feed shafts upon rotation of the latter. In that there is a feed nut on each of the feed screws 137, there will be one thereof located adjacent each corner of the magazine which will move in unison to support the platform 134 at the proper inclination with respect to the gage bars 135. The feed nuts 140 of the feed screws 138 will be similarly located adjacent the corners of the magazine for similar reasons and purposes.

The feed nuts 140 are each provided at their upper ends with elevator platform supporting pawls 141 which will bear the weight of the platform and the paper imposed thereon, but may pivot to an unobstructing position, as shown in Fig. 11, when they pass downwardly by a stack of paper.

All four of the shafts 137 are driven in unison and all four of the shafts 138 are driven in unison but independently of the shafts 137. Which set of feed screws it is desired to operate may be selectively determined. Assuming. for the purpose of illustration, that there is a supply of paper on an elevator platform 134 in proper position relative to the remainder of the operating mechanism of the machine, and that the machine is in operation and further assuming that the upper elevator platform 134 supporting the uppermost stack in the magazine is being operated by the four feed shafts 138, the drive may be explained most clearly from Fig. 11 taken in conjunction with Figs. 12 to 15.

Fig. 11 diagrammatically illustrates the automatic elevating drive. This drive includes a cam 142 on the cam shaft 20 of the machine. During each cycle of operation of the cam shaft 20, which is one complete revolution, one collating operation is accomplished. During the cycle the cam 142 depresses a reciprocable rack 143 vertically reciprocable on the frame, as clearly illustrated in Figs. 7 and 8. The teeth of this rack are engaged with a pinion 144 on a stub shaft 145. This stub shaft, through the medium of a pair of spur gears 146, drives a countershaft 147 by means of a one-way ratchet clutch 148, so that each time the cam shaft goes through one cycle of revolution, the shaft 147 is rotated one increment of rotation, always, of course, in the same direction. This rotation of shaft 147 is imparted from a pinion 149 thereon through gears 150 and 151 to two drive take-01f shafts 152 and 153. Rotatably mounted on the drive take-off shaft 152 is a sprocket 154, and rotatably mounted on the drive take-off shaft 153 is a sprocket 155. Each take-off shaft 152 and 153 is provided with an overrunning clutch 156 and 157, which may be manually operated by reciprocation of manually operable control shafts 158 and 159 to selectively render the clutches 157 and 156 effective or ineffective in clutching the respective sprockets 154 and to the drive take-01f shafts 152 and 153.

The sprocket 154 on the take-off shaft 152 is connected by an endless sprocket chain 160 to a sprocket 161 on a shaft 162. This. shaft is fitted with helical gears 163 mesh.- ing with helical gears 164 on the other pair of feed screws 137 at the opposite end of the magazine. Therefore, as the drive take-01f shaft 152 is constantly driven when. the clutch 157 thereof is engaged, an intermittent drive will be transmitted through the sprocket chain 160 and the shafts 162 and 16211 to drive the four feed screws 137 simultaneously.

Normally, the sprocket 165 and. the sprocket 161 are of the same number of teeth so that both ends of the elevator platform supported by the feed screws thereon move on the same lineal rate. However, in the event that the sheets of paper to be collated are thicker at one end than the other and originally the stack is inclined a greater amount than is normal, the ratio between the sprockets 161 and 165 may be changed so as to compensate for this dilference inthe sheet thickness and inclination and thereby properly present the sheets for collation at the top of. the stack. Such an arrangement is shown in broken lines in Fig. 12. Of course, adjustment of the frame bar 131 longitudinally would change the distances between the shafts 162 and 162a, placing a slack in the chain 160. This may be compensated for by adjustment of the position of a tightener sprocket 167.

Similarly, the sprocket 155 of the drive take-off shaft 153 is provided with an endless sprocket chain 168 which meshes with a. sprocket 169 on a shaft 170 and a sprocket 171 on a shaft 172, and thence with a sprocket pinion 173. The shafts 170 and 172 are fitted with helical gears 174 meshing with helical gears 175 on the. four feed. screws 138. The operation of this drive circuit is the same as that described in connection with the drive take-oh shaft 152 with the exception, of course, that it drives the second set of feed screws 138.

Similarly, this drive of the feed screws 138 may be adjusted by changingthe ratio of the sprockets 171 and 169 and adjustment by a tightener sprocket 176 to similarly provide a differential in drive in opposite ends of the platform for the same purpose as that just described.

The amount of the increment of feed or rate of feed upwardly of the elevators may be adjusted by adjusting the effective length. of the stroke of the reciprocable rack 143. This-adjustment is shown in Figs. 7 and 8, where it will be seen that the rack isprovided with an abutment 177 to engage an adjusting screw 178 which is stationarily fixed to the frame. By adjusting the adjustment screw 17 8 downwardly, the upward stroke of the rack 143 is limited so that the effective stroke imparted thereto by the cam 142 will be shortened. If considerably thicker sheet material is to be collated so that the upward'feed will not be rapid enough within the limits of the cam 142, the ratio of the gears 146 may be changed so that a greater increment of movement will be imparted to the shaft 147 duringeach effective stroke of the rack 143.

It should be stated here that it is not intended that the elevator be moved an increment every time a sheet of: paper is moved-from the stack, because this would require an extraordinarily fine adjustment. It is intended that the upward feed of the elevators in increments be at a rate greater than the rate of the takeoff at the stack, in that there is a'certain tolerance allotted within which'the pick-up nozzle 63 will operate. Therefore, it is intended to elevate the stack to the upper limits of the tolerence and then cease. the upward feed of the elevator until the stack is used up to approximately the lower limit of the tolerance of the nozzle 68.

This is accomplished by automatically latching the rack 143 out of engagement with the cam 142, when the stack has been fed to the. upper limit of tolerance, and automatically releasing the. rack for operation to recommence the upwardfeed whenthe top of the stack has been used up. to. the lower limit of the tolerance. For this purpose I provide an electrical control, as shown particularly in Figs. 6, 7 and 8 of the-drawing.

Reference. being had to those figures, particularly Fig.

til)

6,. it. will. be. seen that on the cam shaft 20 is a cam 179 which engages a. switchv actuating arm 180' to close a switch 181 during that portionof the operation of the pick-up nozzle 68 when. the nozzle is at approximately the top of the stack. When the cam179 closes the switch, this conditions the circuit for closing in the event that the height of the. paper is either at or above the upper limit of tolerance, or at or below the lower limit of its tolerance. If the top of the paper stack is at the upper limit of tolerance, anozzle arm 108 secured at one end to tube 67 on arm 61 will contact a contact arm 113 and complete a. circuit through switch 181, and thence through a relay 182 which, when energized, will close the switches 183'- and 184. The closing. of switch 183 maintains a ciosed circuit. through the relay 182 maintaining the same energized-v to maintain the switch 184 closed, regardless of the opening of the switch 181 or the arm 108 moving outof contact with the arm 113'.

The closing of the switch. 184; and maintaining. it closed, closes a latchingv circuit through a solenoid 185. When this solenoid is energized, it. actuates a keeper 1-86 and moves it into latching position with respect to a latch plate 187 on the rack 143, which engagement maintains the rack. out of operative engagement with the cam 142, thus stopping tliepaper upward feed. The pick-up nozzle 68 then continues topick up paper off the stack until the lower limit of tolerance is reached, at which time the are through which the arm 108 swings will be sutficiently increased to-swing the arm 113 about its pivot a distance moving the switch. actuating armv 188v the distance required to open the switch. 189. When the switch 189 is opened, it opens the circuit of the. relay 182, opening the switches 183 and 184. Opening ofv the switch 184 deenergizes the solenoid 185, causing. the keeper 186 to move out of engagement with the keeper plate 137, releasing. the rack 143 so that it will again commence to be operated by the cam 142. and commence the upward feed of the paper, as previously described.

The rack latching circuit will then be ineffective to again operate the latching means until the top of the stack has again risen to a point where the movement of arm 108 has been so diminished that it will not move the arm 113 a distance suflicient to actuate the switch arm 188 to open the micro-switch 189. However, when the upper tolerance is again reached, which will be at the time when the arm 113. will be so actuated by arm 108 that the contact arm 188 will not move a sufficient distance to open the switch 189, then contact of the arm 108 with arm 113 at the proper period of the cam operation 179 will again close the circuit through the relay 182, the switches 183, 184 closing the circuit through the solenoid and again latching. the rack against movement.

Thus,.it is secnthatby proper timing of the cams 179, the range of tolerance between uppermost and lowermost positions of. the stack top. may be determined and the stack of sheets. automatically operated to keep the paper properly positioned in the manner just previously set forth.

For the purpose of stopping the machine and indicating trouble at a particular station, when there is over upward travel of a stack or jamming on top the stack, I have provided a mechanism shown in Figs. 3 and 4. This mechanism includes a longitudinal bar 223 at each side of each. magazineat the top thereof, as illustrated in Fig. 3. Extending. transversely of the machine and connected at its ends to these'bars 223 is a rigid jamsensing bar 224. The forward ends of thc levers 223 are pivoted to the frame member 130 at 225. At their rear ends, these levers each extend into a socket 22.6 (see Fig. 4). and are: spring-loaded to normally project centrally within. the socket, however, this end of the. bar 223 is permitted. a limited. amountof upward and downward movement. The amount ofzupward movement permitted, as showninFig, 4,1.is sufficient for itto. engage. acontact 227 insulated from the frame and interposed in the sens- .9 ing circuit shown in Fig. 18. A similar contact 228 similarly insulated from the frame is positioned a spaced distance below the normal position of the bar, but in such position that it may be contacted thereby if the bar is depressed. Naturally, if the bar engages either of the contacts 225 or 227, the sensing circuit shown in Fig. 18 will be grounded and thus complete a circuit through a bulb 52 and a relay 53, to open the circuit of the main drive motor 54.

It is seen that if the stack overfeeds upwardly for some reason, it will engage the jam-sensing bar 224 and elevate the members 223 to contact the contacts 227 and elfect closing of the sensing circuit.

If for some reason a jamming occurs in the machine, causing depression of the jam-sensing bar 224, a similar result will be eifected.

In addition to the functions of thejam-sensing bars 224 just described, these bars serve as additional safety devices for manual emergency stopping of the entire machine. For example, if, because of necessity, the machine operator desires to stop the machine operation without taking the time to reach the control button, the operator may, if he is at any point along the work side of the machine, reach for any one of these jam-sensing bars 224 and move it either downwardly or upwardly, and thereby immediately cease the operation of the machine.

1 have also provided a manually controlled mechanism for selectively operating the two sets of feed screws 137 and 138. The rate at which the manually controlled drive operates the feed screws 137 and 138 is much greater than that at which they are operated by the automatic feed heretofore described. The selective manually controlled drive includes a pair of reversible electric motors 190 and t 191 (see Fig. 11), the drive shafts of which are directly connected to the shafts 192 and 193 of the sprocket pinions 166 and 173 which are in mesh with the sprocket chains 166 and 168. 7

As previously stated, only one set of the feed screws 137 and 138 is used at a time and driven automatically to feed the stack of sheets upwardly. Therefore, if desired, the other set of feed screws may be driven in either direction through the proper sprocket pinion 166 or 173 by the proper motor 190 or 191.

The circuit of the motor 190 includes a reversing switch 194 which is provided with a switch actuator 195 which, upon rotation in one direction, will close the switch 194 to drive the motor 190 in one direction, and, upon rotation in the opposite direction, will close the switch and reverse the circuit of the motor and drive it in the opposite direction, there, of course, being a neutral position of the switch. The actuator 195 is actuated by rotation of the manual control shaft 159. The second motor 191 is provided with a similar switch 196 having an actuator 197 similarly operated by the manual control shaft 158.

Referring to the condition shown in Fig. 11, if it is desired to add to the paper supply in the magazine by moving of additional paper upwardly and adding it to the bottom thereof, the feed nuts 140 of the set of the feed screws 137 then not in use may be lowered to their lowermost limit by selective operation of the proper motor 190 to effect this operation. The paper is then stacked on the elevator platform 134 so lowered and the circuit of the motor 190 reversed and closed so that the newly added portion of the stack will be rapidly elevated until it abuts against the bottom of the portion of the stack then in use, at which time the motor 199 circuit is opened. The elevator platform 134 interposed in the stack is then removed. This imposes the weight of the entire stack on the elevator platform 134 just elevated.

Immediately that the interposed elevator platform 134 is removed and the weight of the stack is imposed on the other elevator platform 134 just elevated by the manually controlled feed just described, the automatic drive is switched from the set of feed screws 138 to the set 137 by manually releasing the clutch 156 by game 10 shifting the manual control shaft 159 endwise outwardly and manually engaging the clutch 157 by shifting the manual control shaft 158 cndwise inwardly.

The clutches 156 and 157 are of the overrunning type as illustrated in Figs. 13 and 14.

Each of the clutches 156 and 157 are identical in construction so a description of one thereof suflices for both. They are of more or less conventional design and include a ratchet 198 and a pivotal pawl 199 having a disengaging pin 200. When the pawl 199 is engaged .'ith the clutch part coupled to the sprocket 155, a drive is effected from the shaft 153 to the sprocket. When the pawl 199 is disengaged from the ratchet, no drive is elfected. The pawl 199 is normally engaged with the ratchet, but may be disengaged therefrom by movement of the shiftable clutch part 201 which is fastened to the control shaft 159. When the shifting clutch part 201 is shifted into register with the pawl pin 200, it moves the same and the ratchet radially outward out of mesh with the ratchet, thus disengaging the clutch.

It will be noticed that the control shafts 158 and 159 are secured in the shiftable clutch part 201 of the respective clutches, which clutch parts each have an axially projecting key 202 reciprocable in a diametrical slot in the end of switch actuators 195 and 197.

It is seen by this that regardless of whether the clutches 156 and 157 are engaged or not, rotation of the control shafts 158 and 159 will actuate the switches of the motors 190 and 191.

I have provided means for preventing motor-driven rotation of the pinions 166 and 173 driven by the motors 199 and 191 counter to the direction of the sprocket chains with which said pinions 166 and 173 are in mesh. Such means is effective only when the sprocket chains are eflecting an automatic drive of the stack feeding mechanism. I accomplish this by providing a stop lug 203 on each shiftable clutch part 201 (see Figs. 13

. and 14), which stop lug, when the clutch. is engaged by shifting the associated manual control shaft axially inwardly, will register with a fixed stop abutment 204 on the frame so that the control shaft 159, due to its connection with the shifting clutch part 21?], can only be rotated in one direction.

For example, assuming that the clutch 156 is engaged as is shown in Fig. 13, the lug 283 on the shifting clutch part 291, as shown in Fig. 14, would prevent the shaft 159 from turning the switch actuator 195 in a direction driving its associated motor 191 in a direction causing the latter to drive the pinion 173 in a direction counter to that in which it would be normally driven in automatic drive by the sprocket chain 168. The manual control shaft can, however, be turned in the opposite direction driving the motor 191 to cause rotation of the pinion 173 in the same direction as the sprocket chain 168, causing overrunning of the clutch 156.

Referring again to Fig. 11, after the automatic drive has been transferred from the set of feed screws 138 to the set 137, as just previously described, the feed nuts 14%) may be run down on the feed screws 138 by operation of the motor 191, as previously described. During this operation the feed nuts 140 must pass downwardly along the sides of the stack, and this is the reason for the provision of the pivotal elevator platform holding pawls 141, as previously described. Due to the fact that these pawls are pivoted, they readily pivot to unobstructing positions during the downward movement of the feed nuts 140.

I have incorporated within the machine a means which is operated by the feed nuts when they reach the uppermost and lowermost limits of their travel to automatically open the circuits of the motors and 191 in the event such circuits are closed, so as to prevent jamming or breakage of the parts. This mechanism is most clearly illustrated in Figs. 9, 10 and 16 of the drawings, and comprises at the lower end of the machine a lower feeler lever 211 pivoted to the frame as at 212 and adapted to be engaged by the feed. nuts 140 when the feed nuts reach the lower limit of their travel on their feed screws. For this purpose, the inner end of feeler lever 211 is positioned intermediate feed screws 137 and 138, being one of each of the two sets of feed screws 137 and 138, lever 211 being adapted to be engaged by a nut 140 of either of the feed screws above designated when such nut reaches the lower limit of its travel on one of the identified feed screws. The outer end of feeler lever 211 is connected to a lower vertical slidebar 213 which projects upwardly (see Fig. with its upper end reciprocably projecting into a U-shaped guide 214.

There is an upper feeler lever (not shown) but similar in construction to the lower feeler lever 211 and which is also pivoted to a fixed part of the frame. The inner end of the upper feeler lever is adapted to engage the feed nuts of the two sets of feed screws 137 and 138 as such nuts reach the top limit of their travel on such feed screws. The opposite end of the upper feeler lever is pivoted to the upper end of an upper vertical slidebar 298, such bar being shown in Figs. 9 and 16, the lower end of which bar as shown in Fig. 16 projects into and is reciprocably mounted in a U-shaped guide 209 fixed to a bracket 210 rigidly connected to the frame of the machine. Oscillation of the upper feeler lever results in reciprocation of the lower end of the upper slidebar 208 within the slide guide 209, and similarly oscillation of the lower feeler lever 211 results in vertical reciprocation of the lower slide bar 213 and causes vertical reciprocation of the upper end of said slide bar 2130 in the lower slide guide 214.

Arranged between the slide guides 209 and 214 in side by side relationship therein with their upper ends reciprocably mounted in the upper slide 209 and their lower ends reciprocably mounted in the lower slide guide 214 is a pair of rack bars 215 and 216 which may independently reciprocate to a limited extent in said guides. The rack bar 215 has a segmental rack 217 formed thereon, and the rack bar 216 has a rack segment 218 formed thereon. The rack segment 217 is in mesh with the pinion 219 formed on the shifting clutch part 201 of the clutch 157 (see Figs. 11 and 13). The rack segment 218 is similarly in mesh with the pinion 220 on the shiftable clutch part 201 of the clutch 156. This is so that rotation of the manually controlled shafts 1.58 and 159 to operate the switch actuators 195 will affect the position of the rack segments 217 and 218 and the position of the rack bars 215 and 216 on which they are mounted.

It is intended that downward movement of the upper bar slide caused by upward engagement of the inner end of the upper feeler lever by a feed nut 140 will shift the proper rack segment downwardly to a point turning its meshed pinion to a position placing the associated switch actuator in neutral position. For example, in the event that one of the manually controlled shafts, say 159, is

turned to operate the switch actuator 195 to place the motor 191 in operation, running the feed nuts 140 of the set of feed screws upwardly without any paper being in the machine, when the feed nuts 140 reach the upper limit of their travel, one of the feed nuts will engage the inner end of the upper feeler lever and move the same upwardly. However, at the time that the control shaft 159 and its actuator 195 was rotated to effect closing of the switch, it conditioned the rack bar 216 through the rack 218 by moving it upwardly into engagement with the lower end of the upper slide bar 208, so that any downward movement of the upper slide bar would immediately move the rack bar 216 downwardly, and through the rack segment 218 turn the pinion 220 an amount turning the switch actuator of motor 191 to return the switch of that-motor to neutral position. Consequently, the upward movement of the inner end of the upper feeler lever which is translated into downward movement of the slide bar 208 will effect this operation of opening the motor circuit, when the feed nut reaches the upper limit of its travel.

The operation of the lower feeler lever by a feed nut similarly cuts out the motor. For example, should the manually controlled shaft 159 be turned in a direction closing the circuit of the motor 191 to move the feed nuts downwardly, when the feed nuts reach the lower limit of their travel, they will engage the inner end of the lower feeler lever 211 and move that inner end downwardly. At the time that the manually controlled shaft 159 was rotated to close the switch of the motor 191, it likewise, through the pinion 220 and the rack segment218, shifted the rack bar 216 downwardly so that upon upward movement of the lower slide bar 213 conditioned by engagement of a feed nut with the inner end of the feeler lever 211, the rack bar 216 would be moved upwardly to normal position, effecting turning movement of the switch actuator 195 through the rack segment 218 and the pinion 220 to place the switch of the motor 191 in neutral position, automatically cutting out the motor drive.

Exactly the same operation is effected when the other set of feed screws is operated by its motor through the medium of the control shaft 158, and it is believed that the two operations being identical, there is no necessity for repeating the cut-out operation.

It is believed understood, of course, that the automatic cut-out mechanism just described is provided at each station in that each station is provided with its independent motors 190 and 191.

I have also made provision for opening the circuit of the main shaft drive and to illuminate the out of order signal at a station when the feed nuts 140, when under automatic operation (such as might be the case when the machine runs out of paper), over travel upwardly or reach the upper limit of their travel on the feed screws. This is accomplished through the means of the upper slide bar 208 by forming a switch actuator lug 221 (see Figs. 12, 16 and 18). When the feed nuts 140 over travel upwardly while under automatic operation, no cut-out can be effected by operation of the rack bars 215 and 216 by the upper slide bar 208 because the circuits of the motors 190 and 191 are already open. Consequently, it is necessary to provide the auxiliary means which includes the lug 221, which will engage a contact 222 insulated from the machine and ground the sensing circuit heretofore described, closing a circuit through the indicator bulb 52, through the relay 53, opening the circuit of the main motor 54 of the main drive of the machine.

In the specification as well as in the claims, the machine is described as assembling a plurality of paper sheets such as printed forms, pamphlet pages, and like material. Actually, this machine will operate upon and collate such material as signatures, folded forms, groups of individual sheets held together by adhesive, wire stitching or sewing. Also, it will gather and collate individual elements of the completed sets in varying sizes; that is, the various sheets or folded forms or similar sets fed from each magazine do not need to be uniform in relationship to each other. Certain of the elements fed from their respective stations can be longer or shorter in either or both dimensions than certain other elements, and in fact no two need to be of the same size. Moreover, the individual elements gathered, whether single sheets or folded forms, need not have square corners or straight edges. It is desirable, of course, that the leading edge to be grasped by the grippers shall be straight, but the other edges may be die-cut to irregular outlines.

I also desire to point out that the machine will operate on elements formed of material other than paper; for example, thin plastic or metal sheets which are either rigid or semirigid, and I, therefore, desire to point out that in the claims herein the words sheet and sheets shall include single sheets of any material or signatures or bound groups of individual sheets.

13 H a I I also desire to point out that the machine Jhasthe additional feature that the uppermost sheet in each station is lifted from the stack and conveyed to the gripper with a motion and through a path of travel which avoids scuffing, thereby making the machine entirely practical to assemble and collate sheetscontaining spot carbon or having a sheet of carbon already aifixed to it. Obvously, the next lower sheet in the pile will not be scuffed or marred by the movement of the top sheet into the grippers, nor will the sheet removed be drawn over the next succeeding one on the stack, so that high gloss work can be handled with perfect safety.

From the foregoing, it is obvious that I have provided an exceedingly simple and reliable stack feeding mechanism by which a stack of sheets can be fed upwardly and replenished while the machine is running. Furthermore, automatic means are provided for stopping the operation of the sheet stack feeding mechanism whenever a jamming or like condition occurs.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A sheet stack feeding mechanism, comprising guides for guiding a stack of sheets, means movable toward and away from the top of the stack for successively removing sheets from the stack, means for raising the stack of sheets at a rate greater than that at which the sheets are removed, means responsive to movement of the firstnamed means below a predetermined level of the top of the stack for initiating operation of the second-named means, and for interrupting operation of the secondnamed means when the first-named means is prevented from moving below said level to thereby maintain the top of the stack at a substantially constant level, and means responsive to elevation of the top of the stack above a predetermined level or below a predetermined level for stopping operation of said stack feeding mechamsm.

2. A sheet stack feeding mechanism for feeding sheets singly to a machine, comprising guides for guiding a stack of sheets, means for successively removing sheets from the stack, means for raising the stack of sheets at a rate greater than that at which the sheets are removed, the last-named means comprising a rack, means for reciprocating the rack, an elevator for raising the stack, a drive from the rack to the elevator including an overrunning clutch, means responsive to movement of the first-named means for intermittently interrupting the operation of the rack to maintain the top of the stack at a substantially constant level, and means responsive to elevation of the top of the stack above a pretermined level or below a lower predetermined level for stopping operation of said machine.

3. A sheet stack feeding mechanism, comprising guides for guiding a stack of sheets, an elevator for raising the stack, a'reciprocable rack, a driving connection between the rack and the elevator including an overrunning clutch to provide a one-way drive from the rack to the elevator for raising the stack, a shaft for shifting the clutch into and out of engagement and being rotatable relative to the clutch, a reversible motor for driving the elevator, a switch for the motor operated by rotation of the shaft in one direction to energize the motor for driving the elevator upwardly and operated by rotation of the shaft in the opposite direction to energize the motor for driving the elevator downwardly, said shaft having a neutral position in which said motor is de-energized, and means for preventing rotation of the shaft in said opposite direction whenever the shaft is shifted to engage the clutch.

4. A sheet stack feeding mechanism, comprising guides for guiding] a stack of sheets, an'elevator for" raising the stack, means for driving the elevator upwardly including a clutch, a shaft for shifting the clutch into and out of engagement and being rotatable relative to the ciutch, reversible motor for driving the elevator, a switch for the motor operated by rotation of the shaft in one direction to energize the motor for driving the elevator upwardly and operated by rotation of the shaft in the opposite direction to energize the motor for driving the elevator downwardly, said shaft having a neutral position in which said motor is de-energized and means for preventing r0 tation of the shaft in said opposite direction whenever the shaft is shifted to engage the clutch.

5. A sheet stack feeding mechanism, comprising guides for guiding a stack of sheets, an elevator for raising the stack, means for driving the elevator upwardly including a clutch, a shaft for shifting the clutch into and out of engagement and being rotatable relative to the clutch, a reversible motor for driving the elevator, a switch for the motor operated by rotation of the shaft in one direction to energize the motor for driving the elevator upwardly and operated by rotation of the shaft in the opposite direction to energize the motor for driving the elevator downwardly, said shaft having a neutral position in which said motor is de-energized, means for preventing rotation of the shaft in said opposite direction whenever the shaft is shifted to engage the clutch, and means for inactivating the first-named means whenever the top of the stack rises beyond a predetermined level or falls below another lower predetermined level.

6. A sheet stack feeding mechanism for feeding sheets singly to a machine, comprising guides for guiding a stack of sheets, a first set of feed screws having feed nuts and being rotatable to drive the nuts upwardly or downwardly, a second set of feed screws having feed nuts and being rotatable to drive the nuts upwardly or downwardly, the second-named nuts being arranged to bypass the first-named nuts, a removable platform for each set of feed nuts whereby a reduced stack of sheets can be replenished by placing a new stack of sheets on the platform of the lower inactive feed nuts and raising the platform thereof to run the new stack of sheets against the upper platform, then removing the upper platform and running the upper feed nuts downwardly to a position to receive a new stack, means for driving the feed nuts, and means for inactivating the driving means of said machine whenever the top of the stack rises beyond a predetermined level or falls below another lower predetermined level.

7. A sheet stack feeding mechanism, comprising guides for guiding a stack of sheets, a first set of feed screws having feed nuts and being rotatable to drive the nuts upwardly or downwardly, a second set of feed screws having feed nuts and being rotatable to drive the nuts upwardly or downwardly, the second-named nuts being arranged to by-pass the first-named nuts, a removable platform for each set of feed nuts whereby a reduced stack of sheets can be replenished by placing a new stack of sheets on the platform of the lower inactive feed nuts and raising the platform thereof to run the new stack of sheets against the upper platform, then removing the upper platform and running the upper feed nuts downwardly to a position to receive a new stack, means for driving the feed nuts, including a driving connection to each set of feed screws with each driving connection including a clutch, a shaft for each clutch for shifting said clutch into and out of engagement and being rotatable relative to said clutch, a reversible motor for each set of feed screws for driving the same independent of the driving means, a switch for each motor operated by rotation of the associated shaft in one direction to energize said motor for driving the associated feed screws for raising the platform thereon and operated oppositely upon reverse rotation of said shaft for causing lowering of said platform, each shaft having a 15 neutral positipn in which the associated motor is deenergized, and mean; 01 eaeh shaft for preventing rdtation thereof in opposite direction when the 'shaft is shifted to engage the associated clutch.

Referenes Cited if: he file bf this patent UNITED STATES PATENTS 998,961 Dexter July 25, 1911 1 6 Hoyt Jan. 11, 1916 Iqhrisbn May 12, 19 31 Babici Jilne 6, 1939 G'oebel Dec. 26, 1939 Foweralker June 18, 1940 FOREIGN PATENTS Great Britain Dec, 23;" 1947 Great Britain July 22, 1948