GB2055666A

GB2055666A - Improvements in or relating to apparatus for positioning sheet material

Info

Publication number: GB2055666A
Application number: GB7927844A
Authority: GB
Original assignee: Billows L K
Current assignee: Billows L K
Priority date: 1979-08-10
Filing date: 1979-08-10
Publication date: 1981-03-11
Also published as: DE3029681A1

Abstract

Apparatus for positioning sheet material on a support table 16 prior to making holes in the sheet material by punching or drilling operations comprises a support shaft 2, at least one location block 9, 10, lockable to the shaft, arranged to slide along the shaft, and a wedge- shaped sheet location member 13 for each location block. Each location block has a slot 12 for accommodating the wedge-shaped sheet location member. The apparatus may include a clamping device 1, 6 by means of which it is attachable to the support table. <IMAGE>

Description

SPECIFICATION Improvements in or relating to apparatus for positioning sheet material This invention relates to apparatus for positioning sheet material.

It is sometimes required to make holes in sheet material and prior to making the holes the sheet material must be in a particular position to ensure that the holes are themselves correctly located on the sheet. For example, when making holes in printing plates, films, paper and other sheet material used in the printing, graphic arts, printed circuit board, map-making, drawing, art reproduction and other industries, the sheet material must be so located that the holes appear on a required location with respect to the edges of the sheet material. In many cases, two holes are required and these have to be equi-spaced from the centre line of the sheet.

The sheet material is usually placed on a table which supports the material in a position inclined to the vertical. Along the lower edge of the table is a mechanism for perforating the material usually in the form of hand- or power-operated punches. The material is placed on the lathe with one edge abutting a stop or stops forming part of the mechanism.

The sheet is then centralised and the holes punched.

The accurate location of the holes depends upon the accuracy of centralisation and a number of devices have been proposed for facilitating the centralisation of the sheet.

For example, the perforating mechanism may be fitted with a linear scale that extends over the support table. A block slidably mounted upon the scale can be clamped into a desired position along the scale depending upon the sheet size. Alternatively, the block may be fixed to the scale both being slidably mounted on the mechanism or on the table.

After the block has been set to a required position, the sheet is placed with one edge abutting the stop or stops and an adjacent edge touching the stop.

The position of the sliding block and/or scale is determined by a simple calculation.

This technique requires only simple apparatus but for each different size of sheet a calculation is required and this and the accurate setting of the block and/or scale are sources of error.

Another form of positioning apparatus uses two movable stop blocks one on each side of the support table. The blocks are movable and are linked together so that when one block is moved the other moves by an equal amount in the opposite direction i.e. both blocks move either towards or away from the centre line of the sheet material.

Because of the equal and opposite movements of the stop blocks no calculations are required but the apparatus is relatively complicated and therefore expensive. Moreover, the blocks have to be moved away from a sheet after the latter has been perforated to allow removal of the sheet from the support table.

A further form of positioning apparatus has arms that extend sideways over the table from the punching apparatus. Several "fingers" are pivotally mounted upon each bar at different fixed axial positions thereon depending upon the range of sheet sizes that the apparatus is designed to accommodate. To position a particular size of sheet, the two fingers appropriate to that size are pivoted over into contact with the surface of the support table with sheet located between them with its edges touching the fingers.

This further form of positioning apparatus is of simple construction and requires no calculations but it is possible for the sheet being positioned to slide between a finger and the table surface.

It is an object of the present invention to provide sheet positioning apparatus that is simple to operate and is less subject to errors than previously proposed apparatus.

According to the present invention apparatus for positioning sheet material comprises a support shaft, at least one location block movable along the shaft, means for locking the or each block to the shaft, a sheet locating member, the or each block being adapted to receive the location member contacting part at least of a surface on the block facing, in use, a support surface on which a sheet to be perforated will be mounted.

The apparatus may include a clamping device for clamping it to a support table.

In one embodiment of the apparatus the or each location block is slotted, the location member being receivable in the slot which incorporates the surface.

The location member or the slot may be of wedge-shaped configuration such that when the location member is moved into the slot, the location member also moves towards the support surface on which the sheet will be positioned prior to punching.

The support shaft may be of non-circular cross-section in a plane transverse to its length.

By way of example only, an embodiment of the invention suitable for use with a foil and plate punch will now be described in greater detail with reference to the accompanying drawings of which: Figure 1 is a side view of the embodiment, Figure 2 is a view from underneath, and Figure 3 is an end view.

The positioning apparatus comprises a main support member 1 which supports in cantilever manner a support shaft 2, the end of the shaft 2 being detachably secured in the mem ber.1 by means of a locking screw 3.

The member 1 is "gapped" at 4, the view end of the gap being recessed at 5. A movable "jaw" 6 is positioned in the gap and is mounted upon adjusting screws 7.

The shaft 2 is of non-circular cross-section in a plane transverse to its length, having a flat 8. Slidably mounted upon the shaft are location blocks 9, 10, the flat 8 giving radial orientation of the blocks. Each block has a clamping screw 11 by means of which the block can be fixed to the shaft 2 at a desired position along the length of the latter.

The blocks 9, 10 are of generally rectangular form which seen in plan, side view and elevation and under-surface of each is slotted as at 1 2. The slots are sized to receive a location member 1 3 having one inclined surface 1 4. The location member is chained to the main support member 1 by a chain 1 5 of length sufficient to enable the member to be inserted into a location block regardless of the position of the latter along the length of the shaft 2.

Before use, the apparatus is clamped to a support board 1 6 forming part of a support table, the edge of the board 1 6 being inserted into the gap 4 and the screws 7 adjusted to grip the movable jaw 6 as shown in Fig. 1.

The jaw 6 spreads the clamping force exerted by the screws 7 and thus reduces the possibility of damage to the board. The recess 5 accommodates "edging" 1 7 around the board. Care is taken to ensure that the edge of the board abuts the inner face of the gap 4.

To position a sheet to be perforated, it is necessary merely to select the location block for the sheet size and slide the location member 1 3 into the slot 1 2 of the selected block.

As the member 1 3 moves into the slot, the inclined surface 14 moves towards and then into contact with the surface of the support board 1 6. The member 1 3 finally wedges in place between the surface of the board 1 6 and the edge 1 8 of the slot 1 2. The wedging action is assisted by the normally inclined orientation of the board.

The sheet to be positioned is now placed on the support board and moved into edge contact with the location member 1 3. The member 1 3 is in firm contact with the surface of the board 1 6 so that there is no possibility of the sheet sliding between the member 1 3 and the surface of the board.

After punching the sheet can be removed from the board without any re-adjustment of the position of the respective location block or member.

It will be appreciated that it may be necessary to use two or more sets of apparatus to accommodate sheets whose sizes are such that the difference in size is less than the thickness of a location block. Such extra set or sets of apparatus can conveniently be clamped to the support board in adjacent positions.

It will be appreciated that the location member could have parallel edges with the inclined surface being the inner face of the slot.

Claims

1. Apparatus for positioning sheet material, comprising (i) a support shaft, (ii) at least one location block movable along the shaft, (iii) means for locking the or each block to the shaft, and (iv) a sheet locating member, the or each block being adapted to receive the location member contacting part at least of a surface on the block facing, in use, a support surface on which a sheet to be perforated will be mounted.

2. Apparatus for positioning sheet material as claimed in claim 1, wherein the support shaft is of non-circular cross-section in a plane transverse to its length.

3. Apparatus for positioning sheet material as claimed in claim 2, wherein the support shaft includes a flat surface extending over its length.

4. Apparatus for positioning sheet material as claimed in any one of claims 1 to 3, wherein the or each location block is slotted, the location member being receivable in the slot which incorporates the said surface which, in use, faces the support surface on which a sheet to be perforated will be mounted.

5. Apparatus for positioning sheet material as claimed in claim 4, wherein the location member and slot are so arranged that when the location member is moved into the slot the location member also moves towards the said support surface.

6. Apparatus for positioning sheet material as claimed in claim 5, wherein the location member is of wedge-shaped configuration.

7. Apparatus for positioning sheet material as claimed in any one of claims 1 to 6, and including a clamping device for clamping it to a support table.

8. Apparatus for positioning sheet material as claimed in claim 7, wherein the clamping device is arranged to support the support shaft in cantilever manner.

9. Apparatus for positioning sheet material as claimed in claim 7 or claim 8, wherein the clamping device includes a gap arranged to receive an edge portion of a support board which provides the support surface on which a sheet to be perforated will be mounted.

1 0. Apparatus for positioning sheet material as claimed in claim 9, wherein the gap includes a recess arranged to accommodate a support board with a thickened edge.

11. Apparatus for positioning sheet material as claimed in claim 9 or 10, wherein the clamping device includes a flat movable jaw arranged to vary the gap in the clamping device.

1 2. Apparatus for positioning sheet material substantially as herein described with reference to and as illustrated by the accompanying drawings.