GB2147569A - Stack handling control - Google Patents

Abstract

A paper handling machine, particularly for stacking and delivering formed stacks ready for binding, comprises a stacking station (3) which forms stacks, (10,12) normally two simultaneously, on a track (14), a conveyor for advancing formed stacks (10,12) to a takeoff point, the conveyor comprising a chain (24), normally in endless form, having fingers (26,28) extending therefrom to engage stacks (10,12), and means (30,32) for selectively preventing such engagement by at lean one finger (26) whereby the chain (24) is operable to advance stacks (10,12) on the track (14) in accordance with a predetermined programme. Alignment of the edges of sheets in each stack (10,12) may be effected by side walls, (16,18) at least one of which (16) may be vibrated. <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.

As stacks of sheet portions are formed they must be removed from the stacking station and conveyed to a binder. In an automated process stack formation, conveying and binding can be synchronized to ensure most efficient operation of the system as a whole. The present invention is concerned especially with the problem of handling the formed stacks as they are carried from the stacking station to the binder.

Each formed stack will require the edges of the component sheet portions to be aligned before it is ready for binding. To accomplish this, according to the invention each stack is conveyed from the stacking station along a path having converging side walls up to a stop. The converging side walls draw one opposed pair of edges (normally the longer edges) of the sheet portions into alignment, and engagement with the stop to align one other edge. One of the side walls is usually parallel to the path, the other urging the sheet portions thereagainst. To enhance the alignment at least one of the walls can be vibrated, as can the stop, thereby assisting in the dissipation of static charges that can build up on the sheet portions.The vibration of the or each wall is preferably pivotal about an axis located at the downstream or distal end of the path, and the mean wall spacing can be made variable to accomodate different sized stacks.

As the stacks are conveyed along the path they are normally supported on a stationary track, the conveyor comprising a chain running beneath the track with fingers attached thereto which extend upwards either through or on either side of the track to engage behind a formed stack. A pair of fingers is usually provided for each stack. In this way the fingers co-operate with the stop to accomplish endwise alignment of the sheet portions in the stacks.

If the conveyor mechanism operates continuously, synchronization of the various steps in the process is difficult, and endwise alignment of the formed stacks tends to be unpredictable. In another aspect of the invention, the conveyor operates in steps, to move formed stacks sequentially from the stacking station to the take-off point for the binder. The use of fingers is especially beneficial in this respect, because it further enhances endwise alignment as each stack is effectively stationary against the stop which, if vibrating, cooperates with the respective finger(s) to align the ends. A degree of resilience is preferably incorporated in the finger(s) or its (their) mounting on the chain to avoid damage at the rearwards end of a stack at this point.

In some stacking machines, two stacks are formed simultaneously side by side at this stacking station. The presents a problem for the conveyor mechanism which must be able to remove two formed stacks from the stacking station, while only delivering one to the take-off point for the binder. To meet this difficulty, the invention in a further aspect contemplates an arrangement in which the conveyor can operate in alternate one- and two-step advances two steps to remove formed stacks from the stacking station, and one step to advance an adjacent stack to the take-off point. During the one step advance means are provided to ensure that the stacks being formed at the stacking station are not moved, but all in transit from the station to the take-off point shift one step, thus creating a space between the stacking station and the last stack to leave the station.The succeeding two-step advance then removes two stacks from the station, but delivers only one to the take-off point as the "space" created between pairs of formed stacks is absorbed.

Where the conveyor is of the chain/finger type described above, the fingers are arranged in groups spaced along the chain, each group having a finger or fingers for engaging two stacks formed in the stacking station. The groups are spaced along the chain by substantially two stack lengths. The formed finger or fingers are arranged to pivot below the second or trailing stack being formed in the station or be otherwise rendered inoperative during an one-step advance, but rendered operative again behind the first or leading stack for the subsequent two-step advance. A camming mechanism is described herein for effecting this disengagment of the leading finger or fingers, but other techniques may be em ployed.

At the take-off point each stack is removed along a path to the binder substantially perpendicular to the formation path from the stacking station. To shift each stack from the formation path to a binder conveyor, the invention further provides a device with reciprocating fingers the movement of which corresponds to the delivery of formed stacks at the take-off point. During a forward stroke, the fingers move a leading stack from a rest position to the binder conveyor while shifting a formed stack from the take-off point to the rest position.Both fingers or sets of fingers are adapted to pivot on the return stroke to avoid interference with the leading and formed stacks and at least the take-off finger or fingers for shifting the formed stack cooperate with separate components of the device to pivot without making any contact with the stack which is being delivered along the formation path and of which the component sheet portions are being aligned against the stop. The take-off finger or fingers are preferably pivotable between two extreme positions at which they are in stable equilibrium, and flipped between operative and inoperative position at respective ends of the stroke of the device.

Operation of the stacking station, the formation path conveyor and the take-off device is conveniently controlled by a computer and, as the critical stage is usually the take-off point, operation is dictated by the presence or absence of a stack at the take-off point monitored by a sensor. As soon as the take-off point is clear, the formation conveyor is advanced. Where two stacks are formed simultaneously at the stacking station, advance is by one or two steps, and stack formation is initiated at the end of each two step advance.

The take-off device and sensor can be used also where only a single stack is formed in one stage at the stacking station.

It will be appreciated that the various aspects of the invention can be adapted for use with a stacking station at which any reasonable number of stacks are formed in a single stage. The conveyor advance steps and stack engagement sequence will require synchronization, but the necessary modifications to accommodate stacking stations other than those specifically contemplated herein can be readily made, primarily by adapting the form of the conveyor.

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 an 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 which the formation and delivery of cut lengths is halted. A track conveyor system then operates to shift the formed stacks from stacking station 3 along track 14. For this exercise the track conveyor moves two "steps" to shift both stacks 1 0, 1 2 from the stacking station 3. Immediately the stacks 10, 1 2 are clear of the stacking station 3, formation and delivery of fresh stacks 10', 12' commences. This position is shown in Fig. 1. As the stacks 10, 1 2 move along the track 14 a vibrating wall 16 urges the pages of the cheque book against fixed wall 18 to align their longitudinal edges. At the end of the track 14 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 perpendicular 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 12" 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 1 4 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 secure 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 alterations 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 1 6 and 1 8 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 14 to urge stacks against the fixed wall 1 8. The convergance 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 th 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 1 2" 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 anticlockwise 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 110. 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 116 (Fig.

8-only three are shown) by a bolt 118. 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 122, 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 is 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 or 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 O-ring 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 116.

The inclination of the blocks with respect to the beams 11 2 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 112, 114 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 the 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 differen tial between the guillotine discharge the 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 116 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 11 6. 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 59 filed today and directed to different aspects of the machine described herein.

Claims (14)

1. A paper handling machine for delivering formed stacks of sheet seriatim to a takeoff point, which machine comprises a track; a stacking station for forming at least two adjacent stacks on the track; a track conveyor having a chain running adjacent the track with fingers extending therefrom and into the path of stacks on the track to engage sides of such tracks; means for driving the chain along the track; and means for selectively preventing operative engagement of at least one finger with a said stack during movement of the chain to move stacks along the track in accordance with a predetermined programme to said take-off point.

2. A machine according to Clairn 1 wherein said at least one finger is pivotally mounted on the chain, said preventing means comprising a cam mechanism for pivoting such finger out of a stack-engaging orientation.

3. A machine according to Claim 1 or Claim 2 wherein the track comprises spaced rails, the chain runs below the track, and the fingers extend upwardly therefrom between the rails.

4. A machine according to any preceding Claim wherein the chain is continuous.

5. A machine according to Claim 4 wherein the driving means is operable to drive the chain intermittentiy in stages, and wherein the driving means and the selective preventing means are synchronised with the operation of the stacking station to provide a regular delivery of said stacks at the take-off point.

6. A machine according to Claim 5 wherein the drive means is operable to advance the chain different distances in successive stages according to the demand at the take-off point, and the formation of stacks at the stacking station.

7. A paper handling machine for delivering formed stacks of sheets seriatim to a takeoff point, which mechanism comprises a track; a stacking mechanism for forming stacks on the track; and a track conveyor for advancing formed stacks along the track from the stacking mechanism to the take-off point, the track passing between converging side walls for progressively engaging the edges of sheets in said stacks during their passage along the track, and means being provided for vibrating at least one of the side walls to facilitate alignment of such edges.

8. A machine according to Claim 7 wherein one of the side walls is fixed, and extends parallel to the track.

9. A machine according to Claim 7 or Claim 8 wherein said at least one side wall is mounted for pivotal vibration about an axis located substantially at the take-off point.

10. A machine according to any of Claims 7 to 9 including a stop on the track at the take-off point to which said stacks are to be delivered, means being provided for vibrating the stop to enhance alignment of the ends of a so delivered stack.

11. A machine according to any of Claims 7 to 10 wherein the track conveyor comprises a chain running beneath the track with fingers attached thereto which extend upwards to engage a rearward end of a said stack, which fingers incorporate resilience to minimize damage caused to a said stack as it reaches the take-off point.

12. A paper handling machine according to any preceding Claim including a binder having a binder conveyor; and a take-off mechanism extending from the take-off point to the binder conveyor.

1 3. A machine according to Claim 1 2 wherein the take-off mechanism comprises a beam mounted for reciprocal movement and having a pair of depending fingers for engaging and transferring said stacks from the takeoff point to the binder conveyor.

14. A machine according to Claim 1 2 or Claim 1 3 wherein the take-off mechanism operates to transfer two said stacks simultaneously; a forward stack from a waiting position to the binder conveyor, and a rearward said stack from the take-off point to the waiting position.

1 5. A machine according to any of Claims 1 2 to 14 including a computer for controlling the operation of the stacking mechanism, the track conveyor, and the take-off mechanism in accordance with the demand of the binder.

1 6. A paper handling machine substantially as described herein with reference to the accompanying drawings.