US3451521A

US3451521A - Apparatus for transferring stacks of sheet material including folded paper handkerchiefs and the like

Info

Publication number: US3451521A
Authority: US
Inventors: Jurgen Fehst; Wilhelm Kurten; Herbert Schettlinger
Original assignee: HOBEMA MAS FAB
Current assignee: HOBEMA MAS FAB
Priority date: 1965-08-13
Filing date: 1966-08-15
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24
Also published as: DE1436961A1; BE684933A; DE1436961B2; DE1436961C3

Description

June 24, 1969 J. FEHST ET AL 3,451,521 APPARATUS FOR TRANSFERRING STACKS OF SHEET MATERIAL INCLUDING FOLDED PAPER HANDKEHCHIEFS AND THE LIKE Filed Aug. 15, 1966 Sheet 4 June 24, 1969 J. HSYT ET AL 3,451,521

RIN

APPARATUS FOR TRANSFER TACKS OF SHEET MATERIAL INCLUDING FOLDED PAPER HANDKERCHIEFS AND THE LIKE Filed Aug. 15, 1966 Sheet 3 of 2 United States Patent US. Cl. 19824 11 Claims ABSTRACT OF THE DISCLOSURE An apparatus for transferring stacks of sheet material from a stacking means to a receiving conveyor.

This invention relates in general to sheet material handling machinery, and more particularly to an apparatus for transferring stacks of sheet material, such as folded paper handkerchiefs and the like, from a stacking means to a receiving conveyor.

In general, the apparatus of the invention can be used with any stacking means, such as for example a folding machine of the type commonly used for folding paper handkerchiefs and napkins, or in fact any type which stacks the material sheets one against the other into stacked groups that are delivered in succession upright on their lower edges from the stacking means advancing along a path extending in the direction of stacking, and which arranges the sheets in each stack to define a common sheet edge profile in which the edge of the first sheet of each stack is displaced further transversely with respect to the delivery path than the similar edge of any other sheet in the same stack. Such displacement of the first sheet in each stack enables the individual stacks delivered consecutively to be conveniently distinguished from one another. A stacking machine which provides any other suitable or equivalent means for distinguishing individual stacked groups of sheet material from one another when they are fed out in a continuous train emerging from the delivery point of the machine, can of course be used.

Essentially, the apparatus of the invention can be considered as the combination of a guide means, a transfer carrier means, and a retaining finger means. The guide means in the instant invention extends from the stacking means, or more specifically from the delivery point of the stacking means, to the conveyor which is to receive the individual stacks of sheet material, and said guide means is disposed to receive such stacks delivered by the stacking means and to guide their advancement to the conveyor. The transfer carrier means is disposed at the conveyor end of the guide means and executes repeated movement relative thereto between one position in which it receives each successive stack upon arrival at the conveyor end of the guide means, and another position in which the transfer carrier means deposits the stacks thus received, one at a time, upon the conveyor. The retaining finger means is also located at the conveyor end of the guide means and is arranged to execute repeated movements relative thereto in synchronism with the movement of the transfer carrier means. The retaining finger means moves between a position of engagement with the first sheet of the leading stack approaching the conveyor end of the guide means to retain such stack on the guide means until the transfer carrier means has deposited a previously received stack upon the conveyor and returns to its stackreceiving position, upon which event the retaining finger Patented June 24, 1969 "ice means moves to a disengaged position to release the leading stack upon arrival of the conveyor end of the guide means for reception by the transfer carrier means in its stack-receiving position. For continuous, cyclical operation, the retaining finger means is disposed for return movement into its engagement position after releasing each stack, one at a time, to the transfer carrier means, and thereby engages the first sheet of the next stack to retain it upon the guide means until the transfer carrier means again returns to the stack-receiving position.

Folding machines for paper handkerchiefs and other such articles, as paper napkins and the like, are often equipped with a device which counts olf the folded pieces and stacks them in packs containing the specified number of pieces. As a rule, the stacks are then picked up by hand and the packs are placed into boxes in which they are brought to the packaging machine. To enable the operator who performs this work to grasp the counted packs easily, it is in the prior art to set one pack of counted pieces somewhat higher, and the next pack somewhat lower, alternately, so that the operator can conveniently grasp one pack after the other. It is also in the prior art to set the first piece in a pack somewhat higher, while from the second piece to the last they all remain in the lower position. In this case, too, the operator can easily pick the individual packs from the stack. These arrangements, however, are not suitable for automatically performing the transfer of the packs from the stack to a conveyor or gathering device. In an automatic transfer operation, the packs have to be so arranged that a sensing means can reliably catch the front side of each pack. If the packs are arranged alternately higher and lower as in the prior art, such a sensing means can easily catch the front side of the higher-set pack, but not so readily the front side of the next, lower-set pack. Also, in apparatus in which only the first piece of each pack is set higher, the beginning of the pack cannot be reliably detected, because the single, elevated folded paper handkerchief or paper napkin is too compliant, so that it can be bent over even by the light contact pressure of the sensing means and the sensing means can slip off it.

According to the invention, this problem is solved in that the first piece in the pack is raised the highest, and the height to which the succeeding pieces are raised diminishes down to the last piece. The upper side of the stack thereby takes on the shape of saw teeth, and the sensing means can always catch the front side of each pack, and there is no danger that, due to the compliance of the individual pieces, the sensing means could slip off, because the front piece is well supported by the following pieces. It is not necessary that the height by which the individual pieces are elevated diminish uniformly from the first to the last piece; particularly when the packs contain fairly large numbers of pieces, the lowest position in which the packs lie on the path of the stack could also be reached before the last piece: for example, in the case of packs of 10 pieces, it could be reached by the 4th or 5th piece, so that the 5 to 6 pieces following could lie on the surface bearing the stack and in this manner the stack would be guided more securely.

At the point of transfer from the stack to the conveyor, a finger can expediently be provided, which applies itself each time to the elevated first piece of the pack, releases the first pack for transfer, and again applies itself to the elevated first piece of the next pack following. This release of the first pack in the stack by the finger takes place while a transfer box is located in front of the stack, so that, when the finger is withdrawn, the stack train can advance by about the thickness of one pack, while the transfer box pivots to the conveyor as soon as th; finger has again caught the elevated first piece of the next pack following. After the transfer box has pivoted into the dumping position, a pusher can shove the pack onto a conveying means, which leads the counted packs directly to the packaging machine. In this manner, not only is human labor saved, but the handkerchiefs, napkins or the like are untouched by human hand between the folding and packing operation. This is particuarly important in the case of material that has been sterilized.

In folding machinery of this kind, trouble can c casionally be caused if the thickness of the material being processed in the folding machine is not entirely uniform from batch to batch and within each batch, so that the pressure which the folded packs in the stack exert on the retaining finger varies considerably though the number of packs may be the same, thereby rendering the perfect operation of the transfer device doubtful. The invention further solves the problem of controlling the machine automatically in such a manner that the pressure exerted on the finger by the packs in the stack is always of the same magnitude, regardless of the thickness of the material being processed. This requires that, in the case of thicker material, the number of packs between the folding machine and the transfer point is diminished, and in the case of thinner material, this number is increased.

This problem is solved according to the invention in that the shaft of the finger of the transfer device is connected through an elastic coupling with the drive, and the magnitude of the pivoting of the finger shaft against the drive shaft influences through a controlling device the operating speed of the transfer device or of the folding device, as the case may be. The elastic coupling in other words constitutes a torque meter, and the measured torque, which is an index of the pressure exerted on the finger by the packs compressed by the finger, is kept at a desired value by the variation of the operating speed. Any torque measuring means of the prior art can be used to measure the torque. An especially simple and expedient device for the measurement of the torque is obtained by providing on the finger shaft an arm which, when it deviates from its predetermined setting, i.e., in the event of excessively great or excessively slight stack counterpressure, interrupts one of two light beams which by means of photosensitive elements, e.g., photoelectric cells, act upon switching devices.

It is therefore, an object of the invention to provide an apparatus for transferring stacks of sheet material from a stacking means to a receiving conveyor.

Another object of the invention is to provide an apparatus as aforesaid which features a guide means for guiding the advancement of sheet material stacks, delivered in a consecutive train by the stacking means, to a point of transfer onto the receiving conveyor by a transfer carrier.

A further object of the invention is to provide an apparatus as aforesaid in which the stacks arriving in succession at the transfer point on the guide means are transferred one at a time onto the receiving conveyor by the transfer carrier.

A further object of the invention is to provide an apparatus as aforesaid in which all the stacks travelling on the guide means, except the one being transferred onto the conveyor, are positively retained upon the guide means until they, each in turn are transferred onto the conveyor.

A further object of the invention is to provide an apparatus as aforesaid which features a retaining means that operates in synchronism with the transfer carrier to re lease one stack at a time thereto and retain all other stacks on the guide means.

A further object of the invention is to provide an apparatus as aforesaid wherein the operation of the transfer carrier can be synchronized with the stack delivery rate of the stacking means.

A further object of the invention is to provide an apparatus as aforesaid wherein the rate of stack delivery of the stacking means can be regulated by sensing the force required to retain a column of stacks on the guide means against the influence of advancing forces resulting from the delivery of additional stacks to the column by the stacking means.

Still another and further object of the invention is to provide an apparatus as aforesaid wherein the stack column retaining force is converted into an electrical signal which can be utilized to regulate the stack delivery rate of the stacking means.

Other and further objects and advantages of the invention will become apparent from the following detailed description and accompanying drawings in which:

FIG. 1 is a schematic elevation view of a stack transferring apparatus according to a preferred embodiment of the invention which is adapted to transfer onto a typical conveyor, stacks of folded paper handkerchiefs received from a handkerchief folding machine.

FIG. 2 is a schematic perspective view of the working portion of a stack transferring apparatus according to another embodiment of the invention which can be used in conjunction with the folding machine illustrated in FIG. 1, and which features means for controlling the operating speed of such folding machine in accordance with the force exerted against the retaining means by the column of handkerchief stacks delivered by the folding machine. i

In FIG. 1, a paper web 1 which is to be foldedinto paper handkerchiefs, is fed to a folding apparatus 2 of a conventional type, in which the web 1 is folded lengthwise by the apparatus 2, and is laid in a fanfold manner and cut by a stacking apparatus 3. Guiding rolls 4 are placed ahead of rollers provided in the apparatus 2, and their height is varied, as indicated schematically by .a lever 5 which is moved by a cam 6, such that the rolls 4 also raise and lower accordingly the web 1 being fed to the folding apparatus 2. Cam 6 is so arranged that, during the folding of ten handkerchiefs, rolls 4 and with them the lengthwise folded web 7 are slowly lowered from their highest position, and, after the folding of the tenth handkerchief, rapidly return to the uppermost starting position. In this manner it is brought about that, in the stacks 8 of folded handkerchiefs leaving the folding and cutting apparatus 3, the handkerchiefs or the like are arranged for a common edgewise profile of sawtooth form as represented, in such a manner that the first handkerchief of each stack 8 projects above the preceeding handkerchiefs and is supported by the handkerchiefs that follow it, advancing in succession along a guide means 31.

The transfer point, i.e. Where the stacks 8 are transferred to a receiving conveyor 15, is located at the right end of guide means 31. A pivoting finger 9 rests against the front side of the leading stack 8a. A lever 11 is swung by a rod 10, which is driven synchronously with the stacking apparatus 3, and the transfer carrier 13 is thereby swung up into the position indicated by the broken line. As soon .as the transfer carrier 13 has reached this stack-receiving position, a spring 12 pushes finger 9 up, so that the slightly compressed lead stack 8a expands due to its elasticity and enters into the transfer carrier 13. When the lever 11 returns, first the finger 9 is moved back into its position of rest and applies itself to the front side of the first, elevated folded sheet piece in the pack next following which then becomes the lead stack 8a, then the transfer carrier 13 pivots into the transfer position drawn in solid lines, and a pusher 14 pushes the stack in transfer carrier 13 into the receiver of conveying means 15 located directly in front of the transfer point, and the conveyor 15 carries the stacks to a packaging machine (not shown). This basic process is repeated in synchronism with the folding and stacking devices 2 and 3, the conveyor 15 being expediently likewise driven step.- wise in synchronism therewith.

In the apparatus of FIG. 2, the folded handkerchiefs are arranged to form a sawtooth profile column of stacks 8, as in the apparatus of FIG. 1, and the finger 9 applies itself to the front side of the foremost stack. The transfer of the stacks 8 is again performed in succession, as in the apparatus of FIG. 1, in that a transfer carrier such as a transfer fork 13 is swung upward, then the finger 9 performs a swinging movement in the direction of the arrow 18, thereby releasing the foremost stack 8a, so that it can enter into the transfer fork 13', and the finger then returns to its position of rest and applies itself to the front side of the next following stack 8. The shaft 19 on which the finger 9 is fastened is connected by a schematically indicated elastic coupling 20 to the drive shaft 21. On the shaft 19 there is furthermore fastened an arm 22, which is best made spatular in shape at its free end. This spatular extremity of arm 22 moves between two

photoelectric cell systems

23 and 24. In the proper position, i.e., when the retaining pressure of finger 9 against the stacks 8 has the value which it is intended to have, the lever 22 is between the

photoelectric cell sysytems

23 and 24, so that neither of the two light beams is interrupted. If a section of thicker web 1 material is to be processed, so that the pressure of the stacks 8 against finger 9 increases, finger 9 is driven by the stack column advancing force against the resisting force of the elastic coupling 20, rightwards in the direction of movement of the stacks 8, .and lever 22 tilts accordingly towards photoelectric cell system 23. If the light beam in this system is interrupted during the measurement, a regulator 25, which is indicated only schematically, will increase the operating speed of the transfer device 13 in accordance with the operating speed of the stacking machine 3, so that more stacks are transferred per unit of time than are supplied to take their place in the column on the guide means 31. The number of stacks 8 in the column then decreases and the pressure against finger 9 diminishes. If the pressure against finger 9 becomes too slight, finger 9 will be rotated leftward under the effect of the elastic coupling 20, and lever 22 will approach photoelectric cell system 24. If system 24 is interrupted by the spatula portion of lever 22, regulator 26 will bring about a reduction of the operating speed of the transfer apparatus 13', so that the number of stacks 8 in the column will increase, until the pressure of the stacks 8 against finger 9 has reached the proper value.

Instead of varying the operating speed of the transfer apparatus 13, it can be kept constant and the operating speed of the stacking apparatus 3 can be varied, since the ratio of the two operating speeds to one another is the only thing that has to be varied in order to achieve the aim of varying the number of stacks 8 between the stacking machine 3 and the transfer apparatus 13. By this controlled variation in the number of stacks 8 present in the column on guide means 31, the pressure of the stacks 8 against finger 9 cannot increase to the extent that finger 9 is no longer capable of holding back the stacks 8 or releases more than one stack 8 at a time, and the stack column pressure is always maintained sufiiciently high to assure faultless feeding and uniform transfer.

As can be appreciated from the foregoing description of the invention, the transferring apparatus of the invention contemplates a stacking means, such as the handkerchief folding apparatus 3, which stacks material sheets, such as folded handkerchiefs, one against the other into stacked groups 8 that are delivered in succession upright on their lower edges advancing along a path extending in the direction of stacking defined by the guide means 31. To distinguish one stack 8 from another adjoining stack 8, the stacking means 3 arranges the sheets in each stack 8 so as to define a common edge profile, preferably the sawtoothed profile illustrted in FIGS. 1 and 2, wherein the edge of the first sheet of each stack 8 is displaced further transversely to the delivery path than the similar edge of any other sheet in the same stack 8. This allows the retaining finger 9 to clear the remaining sheets of a lead pack 8a which has just passed into the

transfer carrier

13, 13 when said retaining finger 9 is returned to its engagement position to hold back the following stack 8. It should be noted that while FIGS. 1 and 2 illustrate stacks 8 in which the sheets have been displaced upwardly so that their upper edges define a sawtooth profile, the transfer apparatus of the invention could just as well be adapted for operation with a stacking means (not shown) which stacked groups of sheets displaced laterally so that their lateral edges defined a sawtoothed profile. In such case, the retaining finger 9 would be merely arranged to swing in a generally horizontal plane instead of the vertical plane shown in FIGS. 1 and 2. It therefore can be said, that in the preferred embodiment of the invention, the retaining finger 9 pivots about an axis which is generally parallel to the sheet edges which define the sawtooth profile, such axis being also generally transverse rather than parallel to the direction in which the stacks 8 advance on the guide means 31.

Although FIGS. 1 and 2 specifically illustrate transfer carriers 13, 13' which move pivotally with respect to the guide means 31, and pivot about axes generally parallel to the retaining finger 9 pivot axes and perpendicular to the direction of stack 8 advancement, the invention is not necessarily restricted to such specific type of transfer carrier 13, 13'. In general, any transfer carrier means can be used which is capable of repeated movement relative to the guide means between one position to receive each successive stack 8 upon arrival at the conveyor end of the guide means 31, and another position to deposit stacks 8 thus received, one at a time, upon the conveyor 15.

The retaining finger means used in the invention, essentially must be capable of repeated movement relative to the guide means in synchronism with the movement of the transfer carrier means, and must travel between a position of engagement with the first sheet of the leading stack 8a approaching the conveyor end of the giude means 31, remain in such position of engagement to retain the leading stack 8a on the guide means 31 until the transfer carrier means 13, 13' has deposited a previously received stack upon the conveyor 15 and returned to its stackreceiving position. When the transfer carrier 13, 13' is in its stack-receiving position, the retaining finger means must temporarily travel to its disengaged position to release the van leading stack to the transfer carrier 13, 13', and then return to its engaged position to retain the next leading stack. Such return movement of the retaining finger 9 can of course be accomplished by any conventional mechanical means, such as for example a spring 41 as illustrated in FIG. 1. Likewise, a spring 42 can be used to accomplish or to aid returning the transfer carrier 13 to its stack-receiving position.

FIG. 1 illustrated a linkage means including the levers 10 and 11, and the finger-like spring 12, which is driven in synchronism with the stack delivery rate of the folding machine 3, and which is connected to drive the transfer carrier 13 in synchronism with the output of said folding machine 3. Here the spring 12 and crank arm 43 connected to retaining finger 9 define an intermittent motion transmission means, which by reason of spring 12 being mounted to the rocking lever 11, is driven in synchronism with the movement of the transfer carrier 13, and such intermittent motion transmission means can be considered as being coupled to the finger 9 to rotatably drive same whenever the spring 12 pushes against the crank 43. Thus, a cyclical intermittent swinging movement will be imparted to the finger 9 to swing it into its engagement position and into its disengaged position.

In FIG. 2, the elastic coupling element 20 exemplifies a generalized torque sensing means which is coupled to the finger 9 drive shaft 19 so as to sense the torque transmitted therethrough which maintains the finger 9 in its position of engagement with the leading stack 8a against the influence of forces exerted on the finger 9 by the leading stack 8a which forces tend to urge the finger 9 toward its disengaged position. The light beam interrupter lever 22, the

photoelectric cell systems

23 and 24, and the

regulators

25 and 26 represent a generalized signal generating means which is responsive to the torque sensed by the element 20 to generate a control signal corresponding to such torque and which control signal can be utilized for regulating the stack transfer rate of the transfer carrier 13 in relation to the stack delivery rate of the stacking means 3 so as to correspondingly regulate the number of stacks 8 accumulated on the guide means 31 and thus regulate the forces which are exerted on the finger 9 by the leading stack 8a.

While the particular type of photoelectric signal generating means shown in FIG. 2 provides a discrete, dualsignal control output, other types of signal generating means can be used in conjunction with specialized requirements. For example, the torque-indicating lever 22 can be coupled to drive the arm of a potentiometer (not shown) excited 'by an electrical voltage source so as to provide at such arm terminal an electrical voltage signal which is an analog of the retaining finger 9 stack force condition.

The photoelectric signal generating means of FIG. 2 provides an upper limit stack force sensing photoelectric cell system 23, and a lower limit stack force sensing photoelectric cell system 24, which when their individual light beams are interrupted by lever 22, respectively generate electrical control signals to increase the stack transfer rate of the transfer carrier 13' and thereby reduce the number of stacks 8 accumulated on the guide means 31, or to decrease the stack transfer rate and thereby increase the number of stacks 8- accumulated at a given time. In general, for a fixed length guide means 31, the stack column forces acting against the retaining finger 9 will rise with the number of stacks 8 accumulated, and vice versa.

It should be noted that the number of stacks 8 accumulated on the guide means 31 depends on both the stack delivery rate of the stacking means 3 and the stack transfer rate of the transfer carrier 13'. Where these two rates are simultaneously equal, the average number of accumulated stacks 8 will remain constant. The number of accumulated stacks 8 can be reduced by raising the stack transfer rate above the stack delivery rate, and conversely, the number of accumulated stacks 8 can be increased by lowering the stack transfer rate below the stack delivery rate. Therefore, to maintain the stack column forces Within a predetermined range either the stack delivery rate or the stack transfer rate can be held constant while the other rate is adjusted through the application of a control signal derived from the operation of the torque sensing element 20.

From the foregoing, it can be appreciated by the artisan that the invention is susceptible of numerous obvious modifications and variations to suit the needs of a particular application. However, the invention is intended to be limited only by the following claims in which We have endeavored to claim all inherent novelty.

What is claimed is:

1. An apparatus for transferring stacks of sheet material from a stacking means to a receiving conveyor, said stacking means being a type which stacks the material sheets one against the other into stacked groups that are delivered in succession upright on their lower edges from the stacking means advancing along a path extending in the direction of stacking, with the sheets in each stack being arranged to define a common edge profile in which the edge of the first sheet of each stack is displaced further transversely to the delivery path than the similar edge of any other sheet in the same stack, which comprises a guide means extending from the stacking means to the conveyor and disposed to receive such stacks delivered by the stacking means and to guide approaching the conveyor end of the guide means until their advancement to the conveyor, a transfer carrier means disposed at the conveyor end of said guide means and for repeated movement relative thereto between a position to receive each successive stack upon arrival at the conveyor end of the guide means and a position to deposit the stacks thus received, one at a time, upon the conveyor, a retaining finger means disposed at the conveyor end of said guide means and for repeated movement relative thereto in synchronism with the movement of the transfer carrier means between a position of engagement with the first sheet of the leading stack approaching the conveyor end of the guide means to retain said stack on the guide means until the transfer carrier means has deposited a previously received stack upon the conveyor and returned to its stackreceiving position, and a disengaged position to release said leading stack upon arrival at the conveyor end of the guide means for reception by the transfer carrier means when same is in its stack-receiving position, said retaining finger means being disposed for return movement into its engagement position after releasing each stack, one at a time to the transfer carrier means, to engage the first sheet of the next stack to retain same upon the guide means until the transfer carrier means returns to its stack-receiving position, a drive means disposed between said stacking means and the conveyor end of said guide means to synchronize the repeated movement of said transfer carrier means relative to said stacking means in conjunction with the repeated movement of said retaining finger means, and, a pressure regulating means disposed between said stacking means and the conveyor end of said guide means to regulate the operating speed of said transfer carrier means and said retaining finger means with repeated movement relative thereto in synchronism with said stacking means for the control of variation in quantity of stacks, from varying gauge of different sheet material.

2. The apparatus according to claim 1 wherein said retaining finger means includes a finger member disposed for pivotal movement relative to the guide means about an axis generally transverse to the path of stack advancement thereupon, said finger mmeber being pivotable toward the guide means into a position of engagement with the first sheet of the leading stack to retain same on the guide means, and pivotable away from the guide means into a disengaged position to release the leading stack for reception by the transfer carrier means.

3. The apparatus according to claim 1 wherein said retaining finger means includes a drive shaft disposed for limited bi-directional rotation about its longitudinal axis, and a finger member connected to said drive shaft and extending transversely outward with respect to the rotation axis thereof to swing with the rotation of said shaft, said shaft being disposed for rotation in synchronism with the movement of the transfer carrier means to swing the finger member toward the guide means and into a position of engagement with the first sheet of the leading stack to retain same on the guide means when the transfer carrier means is moved out of its stack-receiving position, and to swing the finger member away from the guide means and into a disengaged position to release the leading stack for reception by the transfer carrier means when same is in its stack-receiving position.

4. The apparatus according to claim 3 including a linkage means dirven in synchronism with the stack delivery rate of said stacking means, said linkage means being operatively connected to said transfer carrier means to drive same in synchronism with said stacking means, and intermittent motion transmission means driven in synchronism with the movement of said transfer carrier means and coupled to said finger member drive shaft to rotatably drive same to impart a cyclical intermittent swinging movement to said finger member wherein said finger member is swung into its engagement position and remains there in engagement with the first sheet of the leading stack thereby retaining same on the guide means until the transfer carrier means assumes its stackreceiving position, and upon such occurrence, said finger member is swung temporarily into its disengaged position to release said leading stack for reception by the transfer carrier means and then returned to its engagement position awaiting the return of the transfer carrier means to its stack-receiving position.

5. The apparatus according to claim 3 including torque sensing means coupled to said finger member drive shaft to sense the torque transmitted therethrough to maintain said finger member in its position of engagement with the leading stack against the influence of forces exerted on the finger member -by said leading stack tending to urge the finger member toward its disengaged position, and signal generating means responsive to the torque sensed by said torque sensing means to generate a control signal corresponding to said torque for regulating the stack transfer rate of the transfer carrier means in relation to the stack delivery rate of the stacking means to correspondingly regulate the number of stacks accumulated on the guide means and thereby regulate the forces exerted on the finger member by the leading stack.

6. The apparatus according to claim 5 wherein said torque sensing means includes an elastic torsion member coupled to said finger member drive shaft to sense the torque transmitted therethrough, and responsive to said torque to execute an angular displacement proportional to the magnitude thereof, and a lever connected to said torsion member to execute an amplified angular movement in accordance with the angular displacement of said torsion member, and wherein said signal generating means is responsive to the angular movement of said lever to generate a control signal corresponding to the torque, and hence the magnitude of the leading stack forces represented by each angular movement.

7. The apparatus according to claim 6 wherein said signal generating means includes a pair of photoelectric cells and a light source means disposed to direct a beam of light incident upon each photoelectric cell, said photoelectric cells being each arranged at characteristic spaced apart locations along and in front of the movement path of said lever with respect to the light source means for interruption of their respective incident light beams by the lever when said lever moves into a position of registry with one of said photoelectric cells, one of said photoelectric cells being disposed at a location along the lever movement path corresponding to a lower limit leading stack force, and the other photoelectric cell being disposed at a location along said path corresponding to an upper limit leading stack force to generate respective electrical signals upon light beam interruption characteristic of such leading stack force conditions.

8. The apparatus according to claim 7 wherein said signal generating means includes a regulator means coupled to the output of each photoelectric cell and responsive to the electrical signal thereof to generate a control signal to increase the stack transfer rate of said transfer carrier means in response to the electrical signal of the upper limit leading stack force sensing photoelectric cell to thereby reduce the number of stacks accumulated on said guide means and thus reduce the magnitude of the leading stack forces below said upper limit value, and to generate a control signal to decrease the stack transfer rate of said transfer carrier means in response to the electrical signal of the lower limit leading stack force sensing photoelectric cell to thereby increase the number of stacks accumulated on the guide means and thus increases the magnitude of the leading stack forces above said lower limit value.

9. The apparatus according to claim 1 including an ejector means operable in synchronism with said transfer carrier means to eject the stack received thereby onto the conveyor when said transfer carrier means is in its stackdepositing position.

10. The apparatus according to claim 1 wherein said transfer carrier means is disposed for pivotal movement relative to said guide means about an axis oriented transversely with respect to the stack advancement path defined thereby.

11. An apparatus for transferring stacks of sheet material to a receiving conveyor which comprises a means of supplying material from continuous rolls containing sheet material, a folding means, a stacking level guide means to adjust the height at which the means of supplying material from said supply means is variably fed to said folding means, a folding and cutting means, a stacking means to stack the material sheets fed at a varying level of height by said stacking level guide means to said folding and cutting means, said stacking means being of a type which stacks the material sheets one against another into stacked groups that are delivered in successio-n upright on their lower edges from the stacking means advancing along a path extending in the direction of stacking, with the sheets in each stack being arranged by said stacking level guide means to define a common edge profiling which the edge of the first sheet of each stack is displaced further transversely to the delivery path than the similar edge of any other sheet in the same stack, a guide means extending from the stacking means to the conveyor and disposed to receive such stacks delivered by the stacking means and to guide their advancement to the conveyor, a transfer carrier means disposed at the conveyor end of said guide means and for repeated movement relative thereto between a position to receive each successive stack upon arrival at the conveyor end of the guide means and a position to deposit the stacks thus received, one at a time, upon the conveyor, a retaining finger means disposed at the conveyor end of said guide means and for repeated movement relative thereto in synchronism with the movement of the transfer carrier means between a position of engagement with the first sheet of the leading stack approaching the conveyor end of the guide means to retain said stack on the guide means until transfer carrier means has deposited a previously received stack upon the conveyor and returned to its stack receiving, and a disengaged position to release said leading stack upon arrival at the conveyor end of the guide means for reception by the transfer carrier means when the same is in its stack receiving position, said retaining finger means disposed for return movement into its engagement position after releasing each stack, one at a time to the transfer carrier means, to engage the first sheet of the next stack to retain same upon the guide means until the transfer carrier means returns to its stack receiving position, a drive means disposed between said stacking means and the conveyor end of said guide means to synchronize the repeated movement of said transfer carrier means relative to said stacking means in conjunction with the repeated movement of said retaining finger means, and, a pressure regulating means disposed between said stacking means and the conveyor end of said guide means to regulate the operating speed of said transfer carrier means and said retaining finger means with repeated movement relative thereto in synchronism with said stacking means for the control of variation in quantity of stacks from varying gauge of different sheet material.

RICHARD E. AEGERTER, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,451,521 June 24, 1969 Jurgen Fehst et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 6 and 7,

"HobemaMaschinenfabrik" should read Hobema-Maschinenfabrik Hermann H. Raths Column 7, line 73, cancel "approaching the conveyor end of the guide means until".

Signed and sealed this 21st day of April 19 0.

(SEAL) Attest:

Edward M. F letcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.