GB2119769A

GB2119769A - A method of separating the individual printed sheets of a stream of overlapping sheets

Info

Publication number: GB2119769A
Application number: GB08311669A
Authority: GB
Inventors: Hans Muller
Original assignee: Grapha Holding AG
Current assignee: Grapha Holding AG
Priority date: 1982-05-05
Filing date: 1983-04-28
Publication date: 1983-11-23
Also published as: GB2119769B; JPH046632B2; DE3315489A1; JPS58202233A; CH656596A5; GB8311669D0

Abstract

A method for separating the printed sheets of a stream of overlapping sheets comprises subdividing said stream into partial streams and feeding the partial streams to a separating device such as, for example, a gripper drum (15). Each partial stream is guided to a temporary storage section (4, 5) and is then guided back therefrom to the separating device (15) whilst still in the form of a partial stream. Then, at each engaging or gripping cycle of the separating device (15), successive printed sheets are engaged and drawn from the partial stream. The feed speed of the partial stream of sheets to the separating device (15) and the operating speed of the separating device (15) are so arranged that, at each gripping cycle, the next printed sheet in succession reaches the separating device (15). <IMAGE>

Description

SPECIFICATION A method of separating the individual printed sheets of a stream of overlapping sheets The present invention relates to a method of separating the individual printed sheets of a stream of overlapping sheets, and more particularly to such a method in which a feeder stream of sheets is subdivided into partial streams and the partial streams are fed to a separating device such as a gripper drum.

In known methods of this kind, the partial streams are conducted into the magazines of feeders of gathering or in-setting machines, and the individual printed sheets are stacked there one above the other. Then the lowest sheet in each case is engaged at the magazine by a separating device such as a gripper drum, drawn from the magazine and thrown on to a conveyor.

A disadvantage of such a method is that the capacity of the magazines is relatively small, which means that, whether manual or automatic operation is used, careful supervision of the content of the magazines and frequent filling-up of' the magazines are needed. In such cases many personnel are needed if operation is manual, whereas, in the case of automatic monitoring and resupplying, a plurality of waiting sections and switch points for the sheets are required.

If it is desired to increase the capacity of the magazines special apparatus is required such as described for example in Swiss patent no.

518176.

It would be desirable to improve the method of the kind initially specified so as to make it possible to increase considerably the storage capacity of the magazines without measures which would involve much financial outlay.

According to the present invention there is provided a method of separating the individual printed sheets of a stream of overlapping sheets comprising the steps of dividing said stream into partial streams of overlapping sheets, guiding each partial stream into a temporary storage section and then guiding said partial stream, still with the sheets thereof overlapping, from said temporary storage section towards qseparating device, the feed speed of the partial stream towards the separating device and the speed of operation of said separating device being so arranged that consecutive sheets of the partial stream arrive at the separating device during consecutive cycles of the separating device whereby successive sheets of said partial stream are engaged by the separating device on successive cycles of said device.

Preferably a partial stream is guided onto a belt and wound therewith onto an associated hub, the belt comprising said temporary storage section.

Conveniently, prior to being guided into the temporary storage section, the pitch of the sheets of the partial stream of overlapping sheets is adjusted to be uniform along the length of the partial stream.

By way of example only, the invention will now be described in greater detail with reference to the accompanying drawings in which: Fig. 1 is a side view of apparatus for performing the method according to the invention, showing a partial stream being wound up, Fig. 2 is the same view of the apparatus of Fig.

1 when unwinding the partial stream, and Fig. 3 shows a variant of details of Fig. 2.

Referring to the drawings, a hub 4 driven by a motor 3 via a friction clutch 2 is rotatably mounted in a housing comprising two parallel plates 1 secured to one another. An elastomeric belt 5 is adapted to be wound on to the hub 4 from a belt supply reel 6 also mounted in the housing, and unwound again. The belt 5 is guided over guide pulleys 7 to 9, forming an entry section 10 from the guide pulley 9 to the roll wound on the hub 4.

As well as the hub 4, the motor 3 drives the belt reel 6 via a clutch 11, and the guide pulley 8.

For winding a partial stream onto the hub 4, a feed belt 12 is arranged at the upstream end of the entry section 10, said feed belt 12 being driven by the motor 3 at the same speed as the belt 5. The partial stream arriving on the feed belt 12, in which a printed sheet is overlapped by the next following sheet, passes beneath an equalising device 1 3 such as is described in Swiss Patent Application No. 9139/80-4. The device 13 sets a uniform interval or pitch for the individual sheets of the partial stream over the entire length of the stream.

When the partial stream of sheets has been fully wound onto the hub 4 by means of the belt 5 it can be forwarded for separation into individual sheets by arranging a discharge belt 14 adjacent the guide pulley 9 downstream of the entry section 10 of the belt 5, said belt 14 being adapted to be driven by the motor 3. A gripper drum 1 5 situated downstream of said discharge belt 14 is also driven by said motor 3. The partial stream is transferred from the belt 5, which has acted as a buffer or temporary storage section, onto the discharge belt 14, where the printed sheets arrive in succession at the region of action of the gripper drum 1 5, are drawn off thereby, and are thrown into the collecting duct 1 6 of a gathering machine.

The speeds of the belt 5, the discharge belt 14 and the gripper drum 1 5 are so arranged relative to one another that, at each gripping cycle of the gripper drum 1 5, a printed sheet always arrives into its effective region of action. Because of the action of the equalising device 1 3, the belt 5 together with the discharge belt 14 and the gripper drum 1 5 can be driven at a uniform speed.

If the intervals at which the sheets of the partial stream are arranged were not uniform, it would be necessary to monitor the intervals on the discharge belt 14 by means of sensors (not shown) and to drive said belt 14 at varying speeds so that it co-operates continuously with the gripperdrum 15.

As Fig. 3 shows, the gripper drum 1 5 can co-operate with a spreading drum 17, for opening the arriving printed sheets and throwing them on to a collecting chain 1 8 of a gathering machine.

Claims

1. A method of separating the individual printed sheets of a stream of overlapping sheets comprising the steps of dividing said stream into partial streams of overlapping sheets, guiding each partial stream into a temporary storage section and then guiding said partial stream, still with the sheets thereof overlapping, from said temporary storage section towards a separating device, the feed speed of the partial stream towards the separating device and the speed of operation of said separating device being so arranged that consecutive sheets of the partial stream arrive at the separating device during consecutive cycles of the separating device whereby successive sheets of said partial stream are engaged by the separating device-on successive cycles of said device.

2. A method as claimed in claim 1 in which a partial stream is guided onto a belt and wound therewith onto an associated hub, the belt comprising said temporary storage section.

3. A method as claimed in claim 1 or claim 2 in which, prior to being guided into the temporary storage section, the pitch of the sheets of the partial stream of overlapping sheets is adjusted to be uniform along the length of the partial stream.

4. A method of separating the individual sheets of a stream of overlapping sheets substantially as described with reference to the accompanying drawings.