GB2240078A

GB2240078A - Conveying stacks to strapping area

Info

Publication number: GB2240078A
Application number: GB9001085A
Authority: GB
Inventors: Clive Brooks
Original assignee: MIRROR GROUP NEWSPAPERS LIMITE
Current assignee: MIRROR GROUP NEWSPAPERS LIMITE
Priority date: 1990-01-17
Filing date: 1990-01-17
Publication date: 1991-07-24
Anticipated expiration: 2010-01-17
Also published as: GB9001085D0; GB2240078B; WO1991010592A1; EP0511242A1; AU7054591A

Abstract

A conveying device for use in a post press system of a newspaper printing works between twin outputs (14) from a newspaper stacking system (4) and the input to a strapping system (8) takes the form of a twin shuttle unit (2). The shuttle unit has a pair of buckets (26, 28) which each reciprocate between a respective station (20, 22) aligned with one of the outputs of the stacking system and an intermediate station (24) aligned with the input to the strapping system. Each bucket is a generally U-shaped member on the base of which the stack is supported. The side walls of the U-shaped members support the sides of the stack. The stack is fed from a bucket at the intermediate station (24) by means of a pusher unit (36).

Description

CONVEYING DEVICE The present invention relates to a conveying device in the form of a twin shuttle unit for use as an interface between a stacking system which produce stacks of newspapers and a strapping system which wraps and straps those stacks in a post press system of a newspaper printing works.

In one existing stacking system, produced by Fe rag AG Foerder-und Verarbeitungssysteme of CH-8340 Hinwil, Switzerland, loose unwrapped stacks of newspapers are presented alternately at twin cell outputs of the stacking system. These loose stacks must then be conveyed to the machines of the strapping system. An existing bundle merging unit (Ferag Type PZF) conveys the loose stacks alternately from each output of the stacking system to the input of a transfer unit to an underwrapper which is the first machine of the strapping system, comprises two curved belt caterpillar conveyors which converge at the input. These curved conveyors have proved unsatisfactory in practice. The technical problems are outlined below.

Firstly, the belt caterpillar conveyors drive the stacks from below. The stacks consist of folded newspapers stacked one on top of another. In many cases the newspapers have been stuffed with various inserts such as magazines and advertising material. This results in the newspapers varying in thickness over their width and tends to increase the instability of the stack. Driving such a stack from below produces shear forces on the stack causing shingling during transport along the conveyor. This means that the structure of the stack is unacceptably degraded for input to the underwrapper of the strapping system.

Secondly, the unstable stacks caused by inserts in the newspaper are prone to being thrown off the conveyer altogether during their passage along the curved path.

These technical problems have existed for some time and there is a long felt want for a satisfactory conveying device to act as a shuttle unit between the twin outputs of a stacking system and the single input of a strapping system.

The present invention seeks to solve these technical problems by providing a conveying device or shuttle unit as defined in any of the appended claims.

The advantage of a shuttle unit in accordance with the invention is that 'buckets' support the stack throughout its transport between the two systems preventing both shingling and the stack being thrown out of the system altogether as previously occurred. In this way the inherent instability of the stack caused by the inserts is controlled.

Other advantageous features of the invention are defined in the claims.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is an isometric view of a shuttle unit in accordance with the invention; and Figure 2 is a plan view showing the shuttle unit interposed between the twin cell outputs of a stacking system and an input to a strapping system.

A shuttle unit 2 is shown interposed between a twin cell output from a FERAG stacking system 4 and a transfer unit 6 providing the input to the strapping system 8 which comprises a duplex underwrapper 10 and a strapping machine 12.

Each of the twin outputs 14 from the strapping system is equipped with a pusher unit 16. The ram of the pusher unit 16 moves from the position shown in solid lines in Figure 2 to the position 16' shown in chain lines in that figure to move a stack of newspapers out of the system. In the arrangement illustrated the stacks are fed into the shuttle unit 2 over a short stretch of driven conveyor 18. The pusher units 16 and conveyor 18 at the two outputs operate alternately so that when one pusher unit is extended to output a stack of newspapers, the other is retracted and ready to receive a fresh stack for output.

The shuttle unit 2 comprises two outer stations 20, 22 each aligned with a respective one of the twin outputs 14 from the stacking system 4. The shuttle unit also has an intermediate station 24 which is aligned with the input passage of the transfer unit 6 of the strapping system. Two buckets 26, 28 are provided. Each bucket 26, 28 comprises a generally U-shaped member sized to receive a stack of newspapers supported on the base of the U with the sides of the stack, transverse to its direction of movement through the strapping system, supported by the side walls of the U-shaped bucket. Spring-loaded retaining lips 30 are provided at the ends of the side walls remote from the stacking system output 14. As shown in Figure 2 these lips are held against their spring-loading by a wall 32 of the shuttle unit at the outer stations 20, 22.When the bucket is moved to the intermediate station 24, the absence of a front wall at that station allows the spring loaded lips 30 to move outwardly as shown by the arrows 34 so that a stack S can be pushed out of the bucket onto the conveyor belt of the transfer unit 6 which feeds the stack into the underwrapper 10 of the strapping system 8. The lips 30 preferably extend along the full height of the edge of the side walls of the bucket to retain the stack S securely in position within the bucket until the stack is to be moved out of the shuttle unit 2. This prevents any shingling occurring.

A pusher unit 36 with ram 38 is provided in order to push a stack S from a bucket at the intermediate station 24 onto the conveyor belt of transfer unit 6 at the input of the strapping system 8.

The buckets 26,28 are moved laterally between the stations by pneumatic or mechanical means. Any known type of reciprocating drive can be used for this purpose. The control for the drive must be such that a bucket is at a receiving outer station 20,22 when a stack is ready to be fed out from the aligned output of the stacking system. At this time the other bucket will be at the intermediate station as shown in Figure 2. An electronic control circuit may be utilised to ensure the required synchronism of this drive with the drivers of the stacking and, if necessary, strapping systems. A suitable input signal for the electronic control circuit can be taken from the ram of the pusher unit 16 of the associated stacking system output.The signal which causes the ram to retract after feeding a stack into the bucket can also be used to actuate the lateral drive for transferring that bucket sideways to the intermediate station 24. An appropriate delay after that actuating signal an actuating signal may be provided to the ram 38 which pushes the stack out of the intermediate station 24 onto the belt of the transfer unit. Once that step is completed the drive for the bucket must move it laterally towards its outer station to allow the bucket from the other station to move into position. It is within the skill of those familiar with electronic timing control circuits to achieve the required synchronisation between the drives to the two buckets and the ram pusher unit 36 using the control signals generated from the stacking system and any appropriate circuit may be employed. Alternatively the required synchronism could be achieved by mechanical means.

While on the belt of the transfer unit 6, the stack S is also supported and driven by means of vertical feed rollers 40 on either side of the stack. These provide additional guidance to the stack on its path into and through the strapping system, which is of otherwise conventional design. The system illustrated diagrammatically here is based on the strapping system manufactured by Pakseal Industries Limited of Cordwallis Industrial Estate, Maidenhead, Berks SL6 7DB.

Claims

1. A twin shuttle unit for conveying loose stacks of newspapers or the like from twin outputs of a stacking system to a single input of a strapping system, characterized in that the shuttle unit comprises three laterally aligned stations, the outer stations each being alignable with a respective output from the stacking system and the intermediate station being alignable with the input to the strapping.system; two buckets each sized to receive a stack and support the base and sides thereof; drive means for moving the buckets alternately between an outer station and the intermediate station; and means for driving a stack from a bucket at the intermediate station into the input of the strapping system.

2. A shuttle unit according to claim 1, wherein each bucket comprises a U-shaped member sized to support a stack on its base with side walls of the U-shaped member supporting the sides of the stack.

3. A shuttle unit according to claim 2, wherein lip means are fitted to the vertical edges of the side walls at an exit end of the bucket in order to retain a stack within the bucket, said lips being movable at the intermediate station into a position out of engagement with the stack to allow the stack to exit the bucket.

4. A shuttle unit according to claim 3, where in the lip means are spring loaded into a position out of engagement with the stack and are held in engagement with the stack by a wall at the outer station.

5. A shuttle unit according to any one of the preceding claims, wherein the means for driving a stack out of the central station comprises a reciprocating pusher unit.

6. A conveying device comprising a pair of buckets which are alternately, reciprocally movable from a respective station at which a bucket is aligned with one of twin outputs of a stacking system in order to receive a stack therefrom, and a common intermediate station aligned with the input to a strapping system, each bucket comprising means for supporting the lower and side faces of the stack parallel with the direction of movement of the stack into the strapping system.

7. A shuttle unit or device in accordance with any one of the preceding claims, further comprising vertical, driven feed rollers aligned with the side edges of the stack as it leaves the bucket at the central station in order to guide the stack into the strapping system.

8. A conveying device substantially as herein described with reference to the accompanying drawings.