GB2147570A - Stacking sheets and stack handling - Google Patents

Abstract

Sheet material from a mechanism (2,4) is delivered successively in substantially the same plane to form a stack (10,12) with the sheets thereof ordered in the same sequence as their delivery, the sheets being passed along a path (100) to a receiving tray or track (14) and the speed of such passage reduced in at least one stage (96,98) in the path to cause successive sheets to overlap prior to receipt in the tray where the stack is completed. Reducing stages (96,98) can be located at the inlet to and/or in the path (100), and may comprise roller devices (96,98,116) arranged successively in the path with means (108) for driving the downstream device (98) at a speed lower than that of the upstream device (96). In another aspect the invention contemplates the simultaneous formation of adjacent stacks (10,12) in which sheets are delivered in substantially parallel streams and then passed along divergent paths to receiving means. In at least one of the paths a skew roller device (96,98,116) is disposed to laterally deflect sheets as they pass therethrough to determine such divergence. <IMAGE>

Description

SPECIFICATION Paper handling machines This invention relates to paper handling machines and especially to such machines in which successive sheets of paper or equivalent material are stacked. The sheets are typically successively cut from a roll or other continuous length, such as fan fold paper, and the resultant stacks can be bound in a subsequent process. Machines of this type have a particular use in the production of bound pads, cheque books and the like, and the present invention can be used to direct advantage in the production of cheque books or similar such volumes where serialized information is to be printed on successive pages or sheets.

In a number of printing processes, such as the printing of cheque books and paper money, a plurality of pages (cheque or notes) are printed simultaneously on a single sheet of material or a single length of material from a roll thereof. The sheet or length is then cut to separate the individual portions which must then be collated into stacks with the portions in order therein. The present invention is directed at machines in which successive portions are printed on a length of material and cut seriatim therefrom.

Successive lengths of material discharged from a cutting mechanism, particularly when the cut length is short; e.g. less than 10 cms are difficult to handle, and the problem of stacking then with assurance that they are in the order in which they are cut is a substantial problem. According to one aspect of the present invention, cut lengths are carried from the cutting mechanism to a receiving tray in such a manner that their speed of movement is reduced at at least one stage. This speed reduction causes an overlap between contiguous cut lengths which, by appropriate arrangement of the carrying apparatus, can ensure that one cut length will always lie underneath the next, or vice versa.

A typical machine according to the above aspect of the invention has two pairs of roller devices through which the cut lengths successively pass after discharge from the cutting mechanism. The first device is driven at a speed compatible with that of the cutter, and the second at a lower speed. The cut lengths overlap between the devices and are discharged from the second device into a tray where they stack in the order in which they overlap between the devices. The overlap may be predetermined by a slight misalignment of the paths through the roller devices dictated for example by the orientation of the devices themselves, or the deployment of suitable deflectors therebetween.Surprisingly, we have found that the speed of the first roller device may be greater than that of the cutter, thereby minimizing the risk of accumulation of cut portions at the cutting mechanism, although it is normally less, causing overlapping to initiate at the first roller device. Once "overlap" has been created, by suitable means as referred to abover, further such means are not needed at a later stage. Further, if a speed reduction is effected at the first roller device stage, the second device can sometimes be dispensed with, and then cut lengths discharged directly from the first roller device into the receiving tray.

Two or more sequences of pages or portions may be printed simultaneously side by side on a length of sheet material, which sequences can be stacked separately. In such cases, the sheet material must be not only cut transversely to sever cut lengths therefrom, but also slit longitudinally to separate the sequences. In order to facilitate this separation, the invention in another aspect is directed at a deflector which receives one of two or more substantially parallel streams of cut lengths from the cutting mechanism, and delivers it along the path distinctly spaced from the other or others.To this end, a feed deflector according to the invention comprises a skew roller device in which at least one first roller is aligned with its axis perpendicular to the initial feed direction, and at least one second roller forming a nip with the first roller but with its axis inclined to that of the first roller in the plane of the feed at direction. One of the rollers, normally the first, is driven, and usually the driven roller is disposed below the feed path. The orientation of the first roller minimizes the twisting of the cut lengths, and the inclined action of the second causes a lateral shifting. The resulting spaced paths can therefore also be substantially parallel.

One form of deflector device has a plurality of second rollers housed in a roller block which is pivotable about an axis perpendicular to the feed path. Two second rollers are rotatable about a common axis such that upon pivoting of the block, said common axis will traverse that of the first. A preferred deflector device has a pair of elongate first rollers extending beneath the feed path substantially perpendicular thereto, and a block housing two pairs of second rollers, each pair being mounted for rotation about a common axis as described above. The block is pivotable about an axis disposed substantially centrally between said common axes and the axes of the first rollers.

The first roller or rollers of the deflector device will normally be sufficiently long to extend the full width of the feed path, and are usually formed with a polished surface. The second rollers will be of much shorter axial length, and have a rougher or friction surface to effect the lateral shift of the cut lengths.

Typically, the second rollers have a natural or synthetic rubber surface, and may comprise O-rings. Thus, the second rollers may take the form of wheels.

A plurality of deflector devices may be disposed in series to act on a stream of cut lengths to effect the necessary displacement, and where there are two streams, one or more deflectors may act on each stream to displace them away from each other. With three streams deflectors may act on the outer two to result in three spaced streams, and it will be appreciated that this aspect of the invention may be applied to any reasonable number of streams by varying the displacement effected on each.

it will also be appreciated that the two aspects of the invention may be combined to produce a plurality of spaced ordered stacks of cut lengths, by driving the deflector device(s) at different speeds from each other and/or the cutting mechanism to achieve the desired overlap between successive cut lengths.

A cheque book assembly machine embodying the present invention will now be described by way of example and with reference to the accompany schematic drawings wherein: Figures 1 and 2 are plan views of the machine at two stages in its operation; Figure 3 shows the format of cheques printed on a portion of fan fold feed paper; Figure 4 is an enlarged elevation of the track conveyor mechanism at the stacking station; Figure 5 is an enlarged section taken on line V-V of Fig. 1 showing the vibrating step at the end of the track conveyor:: Figure 6 is an enlarged section taken on line VI-VI of Fig. 1 showing the wall vibrating mechanism; Figure 7 is en enlarged section taken on the line VII-VII of Fig. 2 showing the take-off mechanism for feeding forms stacks to a binding mechanism; Figure 8 is enlarged partial plan view of the deflector mechanism which serves to separate the feeds of cut lengths of paper from guillotine 2 in Fig. 1 (only components over the paper feed level are shown); Figure 9 is an enlarged sectional elevation showing the feed path of the paper under the components shown in Fig. 8; and Figure 10 shows the drive mechanism for deflector mechanism of Figs. 8 and 9.

Figs. 1 and 2 each show the machine in one of two operating positions. Paper is fed to opposite sides of the machine from two sources and delivered respectively to automatic guillotines 2, 4 at a stacking station 3.

Guillotine 2 receives laser printed paper from a roll which forms the cover and non-serialized sheet components of the cheque book; guillotine 4 receives computer printed paper from a fan fold source which forms the cheques (and cheque-stubs if included). The manner in which the fan fold paper is printed is shown in Fig. 3 when a first series A of cheques are printed on the right hand side and shown and a second series B on the left. The guillotine 4 slits the paper along line 6 and cyclically cuts the papers at lines 8, for eventual formation into stacks 10 and 12 as shown. The laser printed paper is printed in a similar format and a computer (not shown) dictates the operation of the automatic guillotines to sequentially feed the requisite pages to a central track 14.

In passage from the guillotines 2, 4 the respective series are deflected along divergent feed paths to form spaced stacks 10, 1 2 on the track 14. Thus, each stacking operation forms two stacks at the completion of wh;ch the formation and delivery of cut lengths is haited. A track conveyor system then operates to shift the formed stacks from stacking station 3 along track 1 4. For this exercise the track conveyor moves two "steps" to shift both stacks 10, 1 2 from the stacking station 3. Immediateiy the stacks 10, 12 are clear of the stacking station 3, formation and delivery of fresh stacks 1 0', 12' commences. This position is shown in Fig. 1.As the stacks 1 0, 1 2 move along the track 14 a vibrating wall 1 6 urges the pages of the cheque book against fixed wall 1 8 to align their longitudinal edges. At the end of the track 1 4 each stack abuts against a vibrating stop 20 to align the transverse edges. The stack is then ready to transfer to a binder along a perpendicuiar conveyor (not shown) in the direction indicated by arrow 22.

The track conveyor is operated to advance alternately by one and two "steps". As shown in Fig. 1 one "step" advance is required to shift the stack 12" to the end of the track 14 against stop 20, while two "steps" are required to shift freshly formed stacks from the station 3 as described above. A part of the track conveyor is shown in Fig. 4 and comprises a chain 24 running below the track 14 with fingers 26, 28 which extend upwards on either side of the track 1 2. The chain 24 is driven by an adjustable step-drive motor through a gearbox. As such, such an arrangement is well known and is not described in detail herein. The fingers 26, 28 are arranged in groups of four; a forward pair 26 and a rearward pair 28, for simultaneously engaging the back edge of a stack 10, 12, and the rearward pair 28 of one group is spaced from the forward pair 26 of the next group by twice its distance from the forward pair 26 of its own group. The forward pair of fingers 26 in each group are pivotally mounted on the chain 24 and have rollers 30 at their lower end. A cam plate 32 is located under stack 12' in the stacking station 3, and engages rollers 30 prior to the fingers engaging the stack 12'. This causes the fingers 26 to pivot below the stack 12' as the chain 24 moves through the step shown in Fig. 3, and the cam plate 32 releases the fingers 26 beyond the stack 1 2 so they rise again for engagement with stack 10'.Thus, from the position shown in Fig. 1, after removal of stack 10" for binding, the track conveyor advances one "step" to bring stack 1 2" against the stop 20 while the fingers 26 pivot below the stack 12'. At the same time the fingers 26 and 28 behind stacks 10 and 1 2 are both operative and advance the stacks 10 and 1 2 to the position shown in Fig. 2.

The next advance of the track conveyor is by two steps. After removal of stack 12" for binding two steps are required to bring stack 10 against the stop 20. All the fingers 26 and 28 are operative so at the same time, formed stacks 10' and 12' are removed from the stacking station 3. The capacity of the binder is generally slower than that of the stacking station, and the operation of the track conveyor can therefore be controlled in response to the presence or absence of a stack on the track 14 against the stop 20. This is sensed by photo-electric cell 34. When a stack is removed for binding the cell 34 emits a signal which provokes an one- or two-step advance of the track conveyor.

The operation of the machine described above is adapted for the simultaneous formation of two stacks 10, 1 2 and for their transport away from the stacking station 3 for binding. It can though, be easily adapted to single stack formation where, for example a large size cheque book is to be formed, or for some other reason only a single series of documents is to be assembled. By lowering the cam plate 32 and thereby maintaining the forward fingers always operative, each movement of the track conveyor will shift a stack in front of the fingers 26 and the fingers 28 are redundant. The movement of the chain 24 is correspondingly adjusted to advance only in two "step" movements synchronized with stack formation and removal for binding. The cam plate 32 is mounted on pins 36 and inclined slots 38 for easy switching between operative and inoperative positions.Each slot 38 is L-shaped to ensure that the cam plate 32 is secured in its operative position.

The movement of the track conveyor (chain 24) and operation of the guillotines 2, 4 and the binding feed 22 is controlled by a computer (not shown). Sensors on the chain 24 and detectors on the machine frame monitor the movement of the track conveyor and suitable programmes direct the operation of the guillotine to produce the required sequence of pages in the stacks. The machine is thus extremely versatile, and adapted to assemble variety of different products with minimal alteration being required.

Fig. 5 shows in section the vibrating stop 20 at the end of the track conveyor. The stop 20 is adjustably mounted on a plate 40 and secured in a chosen position by locking screw 42 in slot 44. The plate 40 is supported on slides 46 which run on rods 48. A block 50 couples the plate 40 or slides 46 to a bracket 52 by means of a resilient joint 54. The bracket 52 is oscillated by a rotating cam 56 driven by an electric motor 58 secured to machine frame member 60.

The walls 16 and 18 bounding the track 14 converge towards its distal end to align the longitudinal edges of the stacks as they move along the track. To facilitate this alignment the wall 1 6 is vibrated in the plane of the track 1 4 to urge stacks against the fixed wall 1 8. The convergence of the walls is preserved by pivotting the wall 1 6 about a fixed pin (not shown) at the distal end. The vibrating mechanism is shown in Fig. 6 and, in a similar manner as the mechanism of Fig. 5 is driven by a motor 62 rotating a cam 64 to oscillate a bracket 66 coupled to the wall 1 6 by a resilient joint 68.The taper defined by the walls 1 6 and 1 8 is variable to accomodate different sized stacks and the spacing at the distal end of the track 1 4 can correspond closely to the actual transverse dimensions of each cut length in the stack.

Fig. 6 also shows the chain 24 on a central guide roller 86 therefor, and a cover 88 for the track 14 and adjacent components of the machine. A slide guide 90 is suspended from the cover 88 to hold down the stacks 10(12).

At the base of the roller 86 a sensor 92 is shown attached to the chain 24, passing a detector 94. This enables the position and hence the movement of the chain 24 to be monitored.

The take-off mechanism for formed stacks to the binder is shown in Fig. 7. This mechanism has two pairs of fingers 70 and 72 depending from a beam 74. In response to a signal from the binder the beam 74 is moved in the direction of arrow 22 to shift a stack (stack 10" is indicated) onto the binder conveyor (not shown), and simultaneously shifting a stack at the end of the track 1 4 (stack 12" is indicated) to the position previously occupied by stack 10". On the return stroke fingers 70 freely pivots over stack 12", now repositioned, and then falls back to the position illustrated, against pin 76. In order to avoid interference between the finger 72 and a fresh stack (10) reaching the end of the track 14, the finger 72 is also pivotally mounted on a pin 78. It is held in the position shown by an over-centre spring 80.At the end of the forward stroke the extended toe 82 of the finger 72 hits a trip 84 which turns the finger 72 in an anti-clockwise direction as shown. As a consequence the line of action of the spring switches from urging the finger 72 clockwise to anti-clockwise, and the finger rotates and lifts above the level of the stack.

At the end of the return stroke, the toe 82 strikes the frame member 86 to flip it back into an operative orientation.

Figs 8, 9 and 10 show the deflector mechanism for separating the series A and series B sheets as they are discharged from guillotine 2. A similar mechanism serves the same function in separating the feeds from guillotine 4. As shown in Fig. 9, the support for both feed paths is defined by two pairs of rollers 96, 98 and intervening guide plates 100. Each roller 96, 98 extends parallel to the track 14 and is driven by belts 102, 104, 106 from a dual speed drive pulley 108 of an electric motor 11 0. The rollers 96 are driven faster than rollers 98 by virtue of the dual pulley 108. Extending over each pair of rollers 96, 98 is a beam 112, 114 from which which are located four blocks 11 6 (Fig.

only three are shown) by a bolt 11 8.

Each block 11 6 carries four rollers or wheels 1 20 comprising rubber O-rings mounted on rotatable rims. The wheels 1 20 are arranged in pairs, each pair being freely rotatable about a common axis 1 22, 1 24 as shown towards the forward and rearward ends of the blocks 11 6, but with the respective common axes parallel. The blocks are arranged with the axes 122, 1 24 inclined in the plane of the feed paths to the axes of the rollers 96, 98 such that each wheel 1 20 to skew relative to its adjacent roller 96, 98 with which it forms a nip through which cut lengths of paper must pass.The angle of inclination is set by the respective bolt 11 8 in the beam 112, 114 and is variable, but lockable. The blocks 11 6 are supported by the wheels 1 20 is the rollers (96, 98); the bolts 11 8 only determine their orientation. This is achieved by a sliding joint 1 26 which after locking, prevents rotation of the respective block about the axis of bolt 118, but permits the block to rise and fall freely with respect to the beam 11 2 or 114.

In operation a cut length of paper 1 28 at the entrance to the deflector enters the first skew nip between a wheel 120' and roller 96.

The rubber bring engages the paper and drives it along a divergent path parallel to its plan of rotation while the paper slides on the polished chrome surface of roller 96. The wheels 1 20 make substantially point contact with the paper resulting in a relatively high contact friction while there is only low friction contact with the layer polished roller surface.

The wheels on common axes can be coupled to ensure that both the first wheel 120' and the roller 96 drive the paper initially. Surprisingly, the orientation of each cut length of paper does not alter greatly during passage through the deflector, and is discharged only with a lateral shift, even after passage under both pairs of blocks 11 6.

The inclination of the blocks with respect to the beams 112 can be different from that with respect to beam 114, the latter normally being greater. We have found this provides maximum separation with minimum stress on the paper itself. Typical angles of inclination are 3" to 5" with respect to beam 112 and 4" to 6" with respect to beam 114. The difference can be predetermined by connecting the blocks between the beams 11 2, 11 4 by a rigid bar, or an adjustable mechanism if additional versatility is needed.

Only a single (upstream) block 11 6 is shown in Fig. 9. If sufficient deflection can be achieved in a single roller pass. then the second (downstream) set of blocks 11 6 can be dispensed with.

Cut lengths of papers 1 28 are received by the deflector over the first guide plate 100 as shown in Fig. 9 The rollers 96 are driven at a feed speed lower than the discharge speed from the guillotine 2 or 4 so that a subsequent length is approaching the first nip before the previous length has passed through it. The first nip urges the trailing edge of a length against the first guide plate and thus advancing subsequent length overlaps the trailing edge of the previous length. Because the rollers 98 rotate slower than the rollers 96 the degree of overlap is increased under the downstream blocks It is appreciated that the overlap effect is cumulative, but as the stacking process is not continuous as the feed is interrupted during and after the formation of a stack or stacks, for interleaving pages from the other guillotine and stack removal.Thus, by selection of an appropriate speed differential between the guillotine discharge the rollers 96 a satisfactory overlap rate can be established for a stack of given size and composition.

It is to be understood that the overlapping technique can be adopted without the deflector mechanism, and vice versa. As with the deflector, the downstream rollers 98 and blocks 11 6 may be dispensed with if sufficient overlap is achieved at the upstream roller section (96). The deflector is of course unnecessary when the feed sheet has only a single series of units printed, but this does not necessitate removal or replacement of the skew roller blocks 116. The angle of inclination with the beams can merely be reduced to zero and a straight, non-deflected feed is the result.

The machine described herein is adapted for high speed operation, the formation of a stack or stacks at the stacking station taking of the order of five (5) seconds. The speed differential between the rollers 96 and 98 to achieve overlapping as described can be around 50%; typical speeds being 500 r.p.m.

for rollers 96 and 300 r.p.m. for rollers 98. A similar differential can be adopted between the guillotine delivery speed and the first roller set (96) if desired.

Reference is directed to our co-pending Application No. 83241 58 filed today and directed to different aspects of the machine described herein.

Claims (26)

1. A method of forming a stack of sheet material wherein sheets are passed along a feed path to a receiving tray, the speed of passage being reduced in at least one stage in the path to cause successive sheets to overlap prior to receipt in the tray where the stack is completed.

2. A method according to Claim 1 wherein the speed of passage of the sheets is reduced in two stages in the path.

3. A method according to Claim 1 or Claim 2 wherein the path includes a delivery point to which sheets are continuously fed at a constant first speed, and wherein the sheets are removed from the delivery point along the path at a constant second speed lower than the first speed in a first reducing stage.

4. A method according to Claim 2 and Claim 3 wherein sheets are removed from the first stage at a constant third speed lower than the second speed in a second reducing stage.

5. A method according to any preceding Claim wherein the sheets are moved along the path by means of rollers forming part of the path.

6. A method according to Claim 5 wherein the sheets are urged against the rollers in said at least one stage.

7. A method according to Claim 6 wherein the sheets are urged against the rollers by wheels whose axes are inclined relative to the respective rollers whereby the sheets are shifted laterally with respect to the rollers as they pass thereover.

8. A method of forming a stack of sheets substantially as herein described with reference to the accompanying drawings.

9. Apparatus for forming a stack of sheet material comprising a delivery point for receiving sheets at one end of a feed path for directing such sheets from the delivery point to a receiving tray at the other end of the path; and means disposed in the path for reducing the speed of passage of such sheets along the path in at least one reducing stage to cause successive sheets to overlap prior to receipt in the tray.

1 0. Apparatus according to Claim 9 including two said reducing stages.

11. Apparatus according to Claim 9 or Claim 10 wherein said at least one reducing stage comprises first and second roller devices arranged successively in the path, the-apparatus including means for driving the first device at a first speed and the second device at a second speed lower than said first speed.

1 2. Apparatus according to Claim 11 wherein the driving means comprises a dual speed drive pulley coupled respectively to the devices.

1 3. Apparatus according to any of Claims 9 to 1 2 including a reducing stage at said one end of the path comprising means for deliver ing sheets to the delivery point at a constant delivery speed; and a roller device for feeding such sheets along the path from the delivery point at a removing speed lower than said delivery speed.

14. Apparatus according to any of Claims 11 to 1 3 wherein said at least one reducing stage includes means for displacing a downstream sheet from the plane of a succeeding sheet to determine said overlap.

1 5. Apparatus according to any of Claims 9 to 14 wherein said at least one reducing stage comprises first rollers disposed in the path and a roller block over the path with second rollers thereon which with the first rollers define nips through which sheets pass on the path, means being provided for controlling the rotational speed of the first and second rollers relative to the input speed of sheets to said stage.

1 6. Apparatus according to Claim 1 5 wherein the first rollers substantially traverse the path and the second rollers are wheels, the coefficient of friction of the wheels with respect to said sheets being greater than that of the rollers.

1 7. Apparatus according to Claim 1 5 or Claim 1 6 wherein the block is mounted for pivotal movement about an axis perpendicular to the plane of the path to permit the second roller axis to be inclined relative to that of the first rollers, whereby a sheet passing under a so pivoted block is laterally deflected.

1 8. Apparatus for forming a stack of sheet material substantially as described herein with reference to Figs. 8 to 10 of the accompanying drawings.

1 9. A method of simultaneously forming a plurality of stacks of sheet material wherein sheets are delivered in substantially parallel streams and passed along adjacent and divergent feed paths to receiving means, in at least one of which paths a skew roller device deflects sheets in passage from a line parallel to the delivery streams.

20. A method of simultaneously forming a plurality of stacks of sheet material substantially as described herein with reference to the accompanying drawings.

21. Apparatus for simultaneously forming a plurality of stacks of sheet material comprising adjacent delivery points located respectively at one end of adjacent and divergent feed paths; receiving means at the other end of the feed paths; and a skew roller device in at least one of the paths for laterally deflecting sheets in said path from a line parallel to another path.

22. Apparatus according to Claim 21 wherein the skew roller device comprises first rollers mounted on parallel axes in the floor of the paths; and a roller block over said at least one path with second rollers thereon, the axes of the second rollers being inclined relaive to those of the first rollers in plane parallel to said path.

23. Apparatus according to Claim 22 wherein the second rollers are wheels, the coefficient of friction of the wheels with respect to said sheets being greater than that of the rollers.

24. Apparatus according to Claim 22 or Claim 23 wherein the block is mounted for pivotal movement about an axis perpendicular to the plane of the path, and means are provided for setting the orientation of the block to determine said inclination of the second roller axes relative to those of the first rollers.

25. Apparatus according to any of Claims 22 to 24 wherein the block is supported directly by the second rollers on the path.

26. Apparatus for simultaneously forming a plurality of stacks of sheet material substantially as described herein with reference to Figs. 8 to 10 of the accompanying drawings.