GB2300412A - Sheet handling - Google Patents

Abstract

Sheet handling apparatus 10 comprises structure 14 with rollers 15 positionable on rails 36 relative to a sheet cleaning device 30 and having a frame 16 which can receive a stack 22 of sheets 11 (e.g. corrugated board) on pallet 21. Sheets 11 are fed in succession from the top of the stack by pivotable roll 26 into the cleaning device 30. A rotatable stop 40 prevents the next-to-top-most sheet being fed. The frame 14 is raised step-by-step in response to photocell 24 which detects the presence or absence of a top-most sheet. The sheets 11 pass from the device 30 to an infeed mechanism 12 of a sheet handling machine 13.

Description

SHIZT HANDUNG APPARATUS THIS INVENTION relates to sheet handling apparatus.

According to this invention sheet handling apparatus comprises means for feeding sheets in succession from a stack through a sheet surface cleaning device.

The sheets may be fed from the top of the stack.

There may be roller means for feeding the top-most sheets in succession from the stack.

There may be means for raising the stack step by step.

The stack may be raised in response to means for sensing the location of the top-most sheet in the stack.

The stack may be on a removable support.

There may be structure for carrying the support, the structure comprising rolls for use in removal of the support.

There may be stop means for resisting feeding of the next-to-top-most sheet in the stack.

The sheets may pass from the cleaning device to an infeed mechanism of a sheet-handling machine; the infeed mechanism may comprise a hopper or stack of sheets.

The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying schematic drawings, in which: Fig. 1 is a side view of a sheet feed apparatus; and Fig. 2 is an enlarged view of part of Fig. 1.

A sheet feed apparatus 10 is arranged for feeding successive sheets 11 to a feed hopper 12 at the input end of a printing machine 13. The apparatus 10 is primarily for use in feeding flat sheets 11 of corrugated fibre board, but can be used for other forms of fairly thick sheets.

The apparatus 10 comprises a frame structure 14 mounted on spaced pairs of wheels 15 (only two shown) and is provided with a sub-frame 16 carrying a horizontal set of rotatable parallel conveyor rolls 17.

The sub-frame 16 is slidably mounted in the frame 14 for up and down movement (arrow A) under the control of a motor 18.

For example the motor 18 may operate a chain and pinion mechanism shown schematically at 19.

In the down position of the sub-frame 16 the rolls 17 are in line with conveyor rolls 20 on which a pallet 21 carrying a stack 22 of sheets 11 is moved on the rolls 20 onto rolls 17 (arrow B).

A manual control 23 then operates motor 18 to raise the sub-frame 16 until a photocell 24 mounted on frame 14 detects the presence at the appropriate height of the top-most sheet 1 1a in the stack 22. The photocell 24 is connected to a solenoid valve 25 operatively associated with motor 18. A feed roll 26 rotates (arrow C) to feed the top-most sheet 1 la horizontally off the stack 22 towards the machine 13, the photocell 24 detects the absence of a sheet 11 and the valve 25 energises the motor 18 to raise the subframe 16 until the now top-most sheet is engaged by roll 26 to be fed forwards in turn. The stack is thus raised step-by-step. In this way, all the sheets 11 in the stack 22 are friction fed in succession by roll 26.

When the sub-frame 16 reaches a predetermined upper position detected by a photocell 24a, the motor 18 is energised in response to the photocell 24a to lower the sub-frame 16 to its down position at which the pallet 21 can be removed on rolls 20 and replaced with a fresh pallet 21 and stack 22 and the feed sequence is then repeated.

The fibre board sheets 11 by the nature of the material of which they are made carry loose surface fibres which are required to be removed before printing of high quality graphics in machine 13.

The surface fibres are removed in a cleaning head 30 having upper and lower parts 30a, 30b. The cleaning head 30 may use air pressure and vacuum to remove surface fibres and debris from the upper and lower surfaces of the sheets, for example, a cleaning head as supplied by Predictive Maintenance Company Limited of Eldwick, Bingley.

BD16 3HE, England, but other forms of cleaning head can be used.

Upper and lower soft touch rolls 31, 32 receive the sheets 11 from the roll 26 and convey the sheets 11 through the head 30 to further soft touch feed rolls 31a, 32a.

The rolls 31, 32 and 31a, 32a maintain sheet flatness.

Rolls 32 and 32a are driven.

The rolls 31, 32 are positioned to receive the leading end of a sheet 11 before the trailing end has left roll 26. Roll 26 is driven by a suitable motor and is pivotally carried on arm 35 Fig. 2 for movement (arrow D) so that if the roll 26 is raised from the stack 22, feeding stops.

The frame 14 can be moved on rails 36 to adjust the distance between rolls 31, 32 and roll 26 to accommodate stacks 22 of sheets of different lengths.

A stop 40 mounted for rotation is provided between roll 26 and rolls 31, 32 so that if the next-to-top sheet 1 lib is fed forwards with the topmost sheet, the sheet 1 1b engages the stop 40.

When the top-most sheet 11 leaves the head 30 the stop 40 rotates (arrow E) to release sheet 1 1b for forward movement into the nip between rolls 31, 32.

The machine 13 has an input feed device (not shown) of known kind which feeds in succession the bottom sheet in the stack 12a in the hopper 12, the stack 12a being steadily replenished at the top. The stack 12a is sufficient in numbers so that there is no interruption in feed into machine 13 during changing of pallet 21.

The apparatus thus provides a means of automatically detaching sheets from a palletised stack of corrugated sheets and to pass sheets singly through a cleaning head, which applies air pressure and vacuum to remove the fibres and debris from both the upper and lower surfaces of the sheet. The sheets having been passed through the cleaning head are then conveyed into a lead edge feeder of a printing machine, for final processing into printed corrugated fibre board cartons.

The top sheet pull roll apparatus provides a continuous automatic single sheet stream into the combined cleaning head assembly, without the need for manual feeding and pile maintenance of the host machine hopper 12.

The sheets 11 need not be of corrugated fibre board but could be of other material e.g. plastics.

In a modified arrangement means other than friction rolls can be used to remove the sheets from the stack e.g. means using suction.

The machine 13 need not be a printing machine but could for example be a box-making machine or a cutting machine.

The above arrangements are to be contrasted with apparatus for loading hopper 12 in which a stack with sheets vertical is tipped so that the sheets are progressively inclined to the horizontal and are partly spread and removed manually to top-up the stack in the hopper 12; such apparatus occupies considerable floor space and does not incorporate a sheet cleaning device.

Claims (12)

cLA

1. Sheet handling apparatus comprising feed means for feeding sheets in succession from a stack through a sheet surface cleaning device.

2. Apparatus as claimed in Claim 1, in which the sheets are fed from the top of the stack.

3. Apparatus as claimed in Claim 2, comprising roller means for feeding the top-most sheets in succession from the stack.

4. Apparatus as claimed in Claim 1 or claim 2, comprising stop means for resisting feeding of the next-to-top-most sheet in the stack.

5. Apparatus as claimed in any preceding claim, comprising means for raising the stack step-by-step.

6. Apparatus as claimed in Claim 5, comprising means for raising one responsive to means for sensing the location of the tomost sheet in the stack.

7. Apparatus as claimed in any preceding claim, comprising structure for carrying the support, the structures comprising rolls for use in removal of the support.

8. Apparatus as claimed in any preceding claim, in which the sheets pass from the cleaning device to an infeed mechanism of a sheet-handling machine.

9. Apparatus as claimed in Claim 8, in which the infeed mechanism comprises a hopper.

10. Apparatus as claimed in Claim 8, in which the infeed mechanism comprises a stack of sheets.

11. Apparatus as claimed in any preceding claim, in which the sheet surface cleaning device has input feed means, and the sheet is engaged by the input feed means whilst engaged by the feed means.

12. Sheet handling apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.