GB2170484A

GB2170484A - Sheet feeding mechanism

Info

Publication number: GB2170484A
Application number: GB08530908A
Authority: GB
Inventors: Denis Percy Crane
Original assignee: Ofrex Group Holdings PLC
Current assignee: Ofrex Group Holdings PLC
Priority date: 1985-02-01
Filing date: 1985-12-16
Publication date: 1986-08-06
Also published as: GB2170484B; GB8530908D0; GB8502572D0

Abstract

A continuous feeding belt having an upper stretch (16) inclined to the horizontal, feeds sheets from an open bottom container (18) above it. A friction plate (22) mounted above the feeding belt restrains the uppermost of a plurality of sheets of paper, thereby reducing tendency of sheet fed to jam in the gap (20). The mechanism may be used with a document shredding machine. <IMAGE>

Description

SPECIFICATION Sheet Feeding Mechanism Description of Invention This invention is concerned with improvemerits relating to sheet feeding mechanism.

Difficulty is encountered in feeding sheet material from a stack thereof, particularly where it is desired to feed more than one sheet at a time, and/or where it is desired that the mechanism used is simple in its construction and relatively inexpensive.

For example in the feeding of documentary sheet material (such as paper) from a stack thereof to a shredding machine, the number of sheets which it may be desired to feed at a time will be dependent upon the capacity of the shredding machine which is being used. For example, single sheet feeding will lead to an under-utilisation of the shredding machine, whilst if the number of sheets which are fed exceeds above a certain value, the shredding machine will tend to jam.

In general it is also desired that the sheet material be fed from the bottom of a stack, where the sheet material being continuously added to the stack.

Difficulties are encountered in conventional feeding mechanisms for such operations, either in their capability of varying the rate at which the sheet material is fed from the stack (which may be necessary if the feeding mechanism is to be used with shredding machines of different capacities), or in tendency for the sheet material to become jammed.

According to this invention there is provided a sheet feeding mechanism comprising a container into which sheet material may be placed, the container having an open bottom, a feeding belt extending across the open bottom of the container, a gap being provided between the container and the belt on the lowermost side of the container, through which gap a plurality of sheets of the material may be fed simultaneously by the belt, and a control device adapted frictionally to engage the uppermost of such plurality of sheets to restrain feeding movement of said uppermost sheet.

Preferably the control device comprises a plate, the coefficient of friction of which is greater than that of the sheet material being fed. Thus there is a greater tendency for a sheet beneath said uppermost sheet to slide in a feeding movement, than such uppermost sheet to slide.

The friction plate may extend a short distance across the uppermost sheet, but preferably the friction plate extends a sufficient distance such as to engage a substantial part of the width of an uppermost sheet of material, but may if desired be provided by two or more smaller plates, adapted to engage said uppermost sheet at intervals across the width thereof.

The friction plate is preferably urged towards the feeding belt, such as by gravity, and conveniently the friction plate is pivotally mounted at a part thereof adjacent to the gap between the container and the feeding belt, and from its pivotal mounting is inclined downwardly towards the feeding belt, so as to engage such uppermost sheet at a position spaced from said gap.

In this manner the friction plate may be lifted by a plurality of sheets being fed simultaneously through the gap, the weight of the friction plate acting on said uppermost sheet restraining feeding movement of said uppermost sheet as hereinbefore described.

Preferably however the degree of upward movement of the friction plate away from the feeding belt is limited, such as by an adjustment device, thus limiting the number of sheets which may be fed between the friction plate and the belt, as may be determined by prevailing requirements.

According to this invention there is also provided a document shredding machine comprising sheet feeding mechanism of the kind set out in the last preceding paragraph but five, which is adapted to feed a plurality of sheets simultaneously into the nip of the shredding machine.

According to this invention there is also provided a method of feeding sheet material from a stack of sheet material, in which the stack is caused to engage an inclined feeding belt, the feeding belt being operative to feed a plurality of sheets simultaneously through a small gap, and wherein an uppermost sheet of said plurality is frictionally restrained from moving in the direction of feed.

According to this invention there is also provided a method of shredding sheet material, in which a plurality of sheets of documentary material are fed from a stack thereof as set out in the last preceding paragraph, and into the nip of a document shredding machine.

There will now be given a detailed description to be read with reference to the accompanying drawings, of a sheet feeding mechanism which is a preferred embodiment of this invention, and which has been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings: Figure 1 is perspective view of the preferred embodiment; and Figure 2 is a schematic vertical section view of the preferred embodiment.

The feeding mechanism which is a preferred embodiment of this invention comprises a housing having two end casings 6 and 8, the end casing 8 housing an electric motor (not shown) which drives a primary drive wheel 10 (Figure 2).

Extending between the end casings 6 and 8 are three elongate shafts 11, 12 and 13, around which a continuous feeding belt 16 extends.

A drive belt 17 extends around the primary drive wheel 10, and around the shafts 11 and 12, whereby the feeding belt 16 may be caused to move in the direction of the arrow shown in Figure 2.

The upper reach of the feeding belt extends generally within the range 30 to 60 , preferably about 45" to the horizontal, and mounted above said upper reach is a three-sided container or hopper 18, which is open at the top and rear to enable sheet material to be stacked therein, and which is open at the bottom to allow the sheet material to rest on the feeding belt 16.

Between the front face 19 of the hopper and the feeding belt, on the lowermost side, a small gap 20 extends generally the full width of the hopper, allowing when the feeding belt is driven, a plurality of sheets of paper to be fed from the hopper.

The feeding mechanism also comprises a control device afforded by a friction plate 22 which is mounted over the stretch of the feeding belt immediately below the gap 20. The friction plate 22 extends the full width of the hopper, and is pivotally mounted at a point adjacent to the gap, and swings under the action of its own weight towards the belt 16. The coefficient of friction of the plate 22 with the paper being fed is greater than that of the paper-to-paper coefficient, and is conveniently provided by fine carborundum, or by a sheet of fine emery paper secured (such as by adhesive) to a metal backing plate.The effect of the friction plate is to restrain or retard movement of the uppermost of a plurality of sheets of paper fed through the gap by the belt, to reduce the tendency of further sheets of paper being fed into the gap and hence jamming of the machine. The effect of feeding movement of the plurality of sheets is to tend to lift the friction plate 22 with the paper being fed about its pivotal axis away from the belt, the extend of such movement conveniently being limited by a screw-thread adjustment device 26. In this manner, the number of sheets which are allowed to be fed at a time from the stack within the hopper may be restricted to the maximum number permitted for use simultaneously with a document shredding machine.

Whilst in the preferred embodiment the friction plate 22 extends the full width of the hopper, and the uppermost surface of the uppermost sheet of a plurality of sheets fed through the gap 20 by the friction belt, if desired two smaller friction plates may be utilised, which are so positioned as to engage the uppermost sheet at positions spaced across the width thereof.

If desired the side walls of the hopper may be moulded for relative separative movement, to enable the width of the hopper to be adjusted as may be desired.

The sheet feeding mechanism above described may be used with any convenient document shredding machine, such as that disclosed in the specification of our U.K. Patent No. 1572157, which combination is also an embodiment of this invention.

Claims

1. A sheet feeding mechanism comprising a container into which sheet material may be placed, the container having an open bottom, a feeding belt extending across the open bottom of the container, a gap being provided between the container and the belt on the lowermost side of the container, through which gap a plurality of sheets of the material may be fed simultaneously by the belt, and a control device adapted frictionally to engage the uppermost of such plurality of sheets to restrain feeding movement of said uppermost sheet.

2. A sheet feeding mechanism according to Claim 1 wherein the control device comprises a plate, the coefficient of friction of which is greater than that of the sheet material being fed.

3. A sheet feeding mechanism according to Claim 2 wherein the friction plate extends a sufficient distance across the gap such as to engage a substantial part of the width of the uppermost sheet of material.

4. A sheet feeding mechanism according to one of Claims 2 and 3 wherein the friction plate is urged towards the feeding belt.

5. A sheet feeding mechanism according to any one of Claims 3, 2, and 4 wherein the friction plate is pivotal mounted adjacent to the gap between the container and the feeding belt, and from its pivotally mounting is inclined downwardly towards the feeding belt, so as to engage an uppermost sheet at a position spaced from said gap.

6. A sheet feeding mechanism according to any one of Claims 2 to 5 wherein the degree of upward movement of the friction plate away from the feeding belt is limited by an adjustment device.

7. A document shredding machine comprising a sheet feeding mechanism according to any one of the preceding claims, which is adapted to feed a plurality of sheets simultaneously into the nip of the shredding machine.

8. A method of feeding sheet material from a stack of sheet material, in which the stack is caused to engage a feeding belt, the feeding belt being operative to feed a plurality of sheets through a small gap, and wherein an uppermost sheet of said plurality is frictionally restrained from moving in the direction of feed.

9. A method of shredding sheet material, in which a plurality of sheets of documentary material are fed from a stack thereof by a method according to Claim 8, and into the nip of a document shredding machine.

10. A sheet feeding mechanism constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

11. A document shredding machine comprising sheet feeding mechanism constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

12. A method of feeding sheet material from a stack of sheet material, when carried out substantially as hereinbefore described with reference to the accompanying drawings.

13. Any novel feature of novel combination of features hereinabove described and/or shown in the accompanying drawings.