GB2132544A

GB2132544A - Improvements in or relating to press knives

Info

Publication number: GB2132544A
Application number: GB08331814A
Authority: GB
Inventors: Michael Steadman; Ronald Herbert Luck
Original assignee: JOHNSON HAYNES PRESS KNIVES LI
Current assignee: JOHNSON HAYNES PRESS KNIVES LI
Priority date: 1982-12-21
Filing date: 1983-11-29
Publication date: 1984-07-11
Also published as: GB8331814D0; GB2132544B

Abstract

A press knife for cutting sheet material, comprising a continuous length of blade (2) in the shape of a desired outline to be cut in sheet material and having at least one continuous cutting edge (4) (Fig. 4) and preferably two, said knife also having at least one elongate reinforcing member (6) extending transversely of the knife and linking one portion of the blade with a generally oppositely disposed portion. The knife is provided with two support plates (8) shaped to fit within the perimeter of the continuous blade (2) and arranged so that the reinforcing member (6) lies between the plates (8), and at least one marking strip (14) received in a slot (12) (Fig. 3) of one plate (8) and in a congruently disposed slot (12) in the second plate so as to bridge the two plates and retain them in position with respect to the blade. <IMAGE>

Description

SPECIFICATION Improvements in or relating to press knives The invention is concerned with improvements in or relating to press knives.

It is well known to cut sheet material, for example leather or poromeric plastics material for use in the manufacture of footwear, by laying the material upon the bed of a press of a suitable type and placing a press knife, usually referred to as a clicking knife, on the surface material prior to applying pressure from a press head to force the edges of the knife through the material. The press head may be operated hydraulically or by any suitable power means.

Where the material is to be used in the manufacture of footwear, it is conventional practice to cut portions of the footwear uppers, such as vamps and quarters, from the sheet using a clicking knife, and then to apply to the surface of the cut upper portion a pattern of marking, either by indentation or by transfer of a suitable marking medium, for example ink, to act as a guide for subsequent assembly of the upper portion to other upper portions by means of stitching or welding.

It is an object of the invention to provide a press knife which is capable of cutting and marking portions of sheet material in a single operation.

The invention therefore provides a press knife comprising a continuous length of blade adapted to define a desired shape to be cut from sheet material and having at least one continuous cutting edge, said knife also having at least one elongate reinforcing member exfending transversely of the knife and linking one portion of the blade with a generally oppositely disposed portion thereof, wherein there are provided two support plates shaped to fit with( the perimeter of the continuo.us blade and arranged so that the reinforcing member lies between said plates, and at least one marking strip adapted to be received in a slot of one plate and in a congruently disposed slot in the second plate so as to bridge the two plates and retain them in position with respect to the blade.

It will be understood that there may be one marking strip disposed at a location between two elongate reinforcing members in order to obtain the necessary retention, or where there is only one reinforcing member, there may be at least two marking strips, one on each side of the reinforcing member. Within practical limits, there may, of course, be any desired number of marking strips or reinforcing members.

The marking strip(s) may be formed from a continuous length of any suitable strip material and have a constant cross section which may conveniently be provided with a first shoulder portion at a marginal portion of the strip and bearing a marking edge, and a second shoulder portion spaced slightly inwardly of the first shoulder portion by an amount approximately equal to the thickness of the support plate so that lip portions of the slot formed therein are received between the two shoulder portions of the strip.

Conveniently, the blade has two cutting edges to ensure that when the upper portions of a pair of shoes are cut, there is exact mirror-image identity between the corresponding portions of the left and of the right shoe. Thus the marking strip will have two marking edges and four shoulder portions.

There will now be described an example of a press knife according to the invention. It will be understood that the description which is to be read with reference to the drawings is given by way of example only and not by way of limitation.

In the drawings: Figure 1 is a plan view of a press knife according to the invention; Figure 2 is a cross-section on line Il-Il of Figure 1; Figure 3 is an enlarged fragmentary view of Figure 2; Figure 4 is a perspective view of the knife; Figure 5 is a portion of marking strip.

The press knife to be described comprises a continuous length of steel blade 2 having two cutting edges 4. It is thus suitable for cutting two mirror-image quarters. Two elongate reinforcing members 6 each span two opposed portions of the blade.

Two support plates 8, cut from any suitable stiff board or in the present example from polypropylene sheet, are received within the perimeter of the blade so as to fit closely thereto, leaving a gap 10 for ease of handling the knife, for example receiving a storage rod or hook. Each plate bears a plurality of slots 12 (Figure 3) forming a pattern. The reinforcing members 6 lies between the two plates 8, which are retained in position by means of a plurality of marking strips 14 cut to length to be received with the slots 1 2 of the support plates.

The marking strip of the present example is formed from a strip of stiffly rigid polyvinylchloride (P.V.C.) having a constant cross-section and is provided with two marking edges 1 6 more clearly shown in Figure 5. Each edge 1 6 is formed on a shoulder portion 1 8 of the strip cross section and inwardly of shoulder portion 1 8 is provided a second shoulder portion 20 at a distance corresponding to the thickness of the support plates 8. The depth of the strip from one edge 1 6 to the opposite edge 1 6 is slightly less than the depth of the blade so that when the knife is used the blade will penetrate the leather or plastics material whereas the marking strip is only required to form a mark or indentation in the surface thereof.

Thus the marking strips 14 are thus held captive in their correct position within the perimeter of the blade by spanning the support plates 8 and trapping the reinforcing member 6 therebetween.

While the example above describes a marking strip which is of P.V.C., it will be understood that any suitable material may be selected, for example nylon, or metal such as aluminium.

Various modifications may be made within the scope of the invention as defined by the following

Claims

claims. CLAIMS

1. A press knife comprising a continuous length of blade adapted to define a desired shape to be cut from sheet material and having at least one continuous cutting edge, said knife also having at least one elongate reinforcing member extending transversely of the knife and linking one portion of the blade with a generally oppositely disposed portion thereof, wherein there are provided two support plates shaped to fit within the perimeter of the continuous blade and arranged so that the reinforcing member lies between said plates, and at least one marking strip adapted to be received in a slot of one plate and in a congruently disposed slot in the second plate so as to bridge the two plates and retain them in position with respect to the blade.

2. A press knife as claimed in claim 1 wherein there is one marking strip disposed at a location between two elongate reinforcing members.

3. A press knife as claimed in claim 1 where there is one elongate reinforcing member disposed at a location between two marking strips.

4. A press knife as claimed in any one of the preceding claims wherein the or each marking strip has a cross section provided with a first shoulder portion bearing a marking edge, and a second shoulder portion spaced slightly inwardly of the first shoulder portion by an amount approximately equal to the thickness of the support plate so that lip portions of the slot formed therein are received between the two shoulder portions of the strip.

5. A press knife as claimed in claim 4 wherein the blade has two cutting edges and the or each marking strip has two marking edges, each borne on one of two first shoulder portions, said first shoulder portions being provided on opposite marginal portions of the strip.

6. A press knife as claimed in claim 5, wherein the depth of the blade between cutting edges is greater than the depth of the strip between the two marking edges thereof to permit the cutting edges to penetrate sheet material to be cut while the marking strip contacts the sheet material only to mark it.

7. A press knife as claimed in any one of the preceding claims, wherein edges of the two support plates are received within the blade perimeter to fit closely thereto except for one region in which an edge of each plate is spaced from the blade to form a gap into which a storage rod or hook is receivable.

8. A press knife constructed and arranged substantially as hereinbefore described with reference to and as shown in the drawings.