GB2130510A

GB2130510A - Razor blade production

Info

Publication number: GB2130510A
Application number: GB08233561A
Authority: GB
Inventors: John W R Hallewell
Original assignee: Toolmasters Ltd
Current assignee: Toolmasters Ltd
Priority date: 1982-11-24
Filing date: 1982-11-24
Publication date: 1984-06-06
Also published as: GB2130510B

Abstract

A method of production of single edged razor blades from double edged blade strip stock 2, rather than from the conventional narrower single edged blade stock, by forming in the strip not only the usual central slots 6 but also, flanking and parallel to each central slot 6, a pair of auxiliary slots 8, cropping the stamped strip as at 14 to form individual double edged blades 4, and then forming single edged blades 16 therefrom by cutting away the end portions 20 of the slots 8 or the end portions 18 of slots 6 and 8. <IMAGE>

Description

SPECIFICATION Razor blade production This invention relates to the production of single edged razor blades from strip stock of a width suited for the production of conventional double edged razor blades.

Double edged razor blades are conventionally made from steel strip 22.4 mm wide which is initially fed from the coil through a stamping tool in a power press wherein the strip is perforated as required; the perforations in particular include or consist of longitudinally spaced axial slots, one for each eventual individual blade, these slots being used for positive location of the longitudinally advancing strip in subsequent treatment steps, and of course locating the individual blades for use in razors.The perforated strip is then usually re-coiled, fed from the coil through heat-treatment and then re-coiled before being fed from the coil through sharpening apparatus which sharpens the two lateral edges of the strip; the resulting double edge strip is then cropped to length, i.e. cut between adjacent axial slots to form individual double edged blades which are then stacked and which may then be surface coated in the stack.

Single edged blades for use in bonded blade cartridges, are ideally made in similar fashion from strip 17 to 18 mm wide, the double edged blades initially produced being cut centrally to provide two sets of singled edged blades.

In many cases, however, the blade manufacturer has insufficient demand for single edged blades to justify dedicating a production line solely for their manufacture. Furthermore, excessive downtime and undue expense is involved in interrupting double edged blade production and re-setting the line for the occasional run with narrower strip for the production of single edged blades. Accordingly, single edged blades are frequently made from the same wider strip as used for the double edged blades,but this involves the step of cutting the single edged blades from along the whole length of either side of the initially produced double edged blades, this being a difficult and expensive operation.

The present invention overcomes the latter problem and facilities the production of single edged blades from conventional double edged blade strip stock by forming during the strip perforation stage auxiliary pairs of slots flanking and parallel to the said axial slots, there being one such pair for each said axial slot and the outermost boundary of each auxiliary slot corresponding to and extending substantially the length of the unsharpened longitudinal margin of the corresponding eventual single edged blade. The strip perforated in this way can then be treated and cropped in conventional manner to yield double edged blades, following which it is necessary only to cut through the ends of the auxiliary (or auxiliary and axial) slots to yield the required single edged blades.This final cutting is conveniently effected (usually on a stack of the initially produced double edged blades) by means of an abrasive wheel cut-off machine.

The invention is illustrated, by way of example only, by the following description to be taken in conjunction with the accompanying drawing, in which the single Figure is a plan view of steel strip after perforation according to the invention and indicating where the metal is cropped to form individual double edged blades and then cut away to provide the required single edged blades.

The single Fig. of the drawing shows part of a continuous strip 2 of steel 22.4 mm wide, the drawing being to scale. The strip has been perforated by stamping tools in a power press to form therein, within each length 4 corresponding to an eventual individual double edged blade, an axial slot 6 flanked by parallel auxiliary slots 8 and, between slots 8 and the strip edges 10, respective lines of holes 12. Axial slot 6 serves for location of the strip during subsequent conventional treatment of the strip in the initial production of double edged blades, and the holes 12 serve for location of the corresponding individual single edged blades when they are mounted in or on a moulded plastics razor head cartridge.The perforated strip as illustrated in the Figure is treated conventionally as previously described, e.g. recoiled, uncoiled and heat-treated, recoiled, uncoiled and sharpened along both edges 10, and then cropped along lines 14 to yield individual double edged blades 4 which are stacked and then, if desired, surface coated (e.g. with polytetrafluoroethylene) in the stack. To produce single edged blades 16 it is only necessary to remove the end portions 18 indicated by cross-hatching, or if desired just the smaller individual portions 20 at the ends of slots 8; this is usually done by means of an abrasive wheel cut-off acting on the double edged blades in the stack.

This procedure is much easier and cheaper and more reliable than the general prior practice of initially forming the double edged blades without the auxiliary slots 8 and then cutting the whole length of this blade along lines corresponding to the outermost edges of the slots 8.

In a modified procedure according to the invention, axial slot 6 and its auxiliary slots 8 are replaced by a single wide slot extending the full width between the outermost edges of slots 8, portions 18 of the initially produced double edged blades and then being removed as before to give the single edged blades 16.

This however is a less satisfactory operation and involved some re-setting of the normal production line for two edged blades in order to accommodate the wider slot.

The invention resides not only in the indicated method, but also in the apparatus or plant for carrying it out - and in particular the stamping equipment for forming in the strip stock the central and flanking longitudinal slots (as at 6 and 8 in the drawing) or the mentioned alternative wide central longitudinal slots.

Claims

1. A method of making single edged razor blade which comprises making double edged blades each having an auxiliary pair of slots flanking and parallel to the central slot and cutting through or away the ends of the auxiliary slots.

2. A method according to claim 1 wherein the said cutting is effected on a stack of the initially produced double edged blades.

3. A method according to claim 1 or 2 wherein the double edged blades are surface coated.

4. A method according to any of claims 1 to 3 wherein the ends of the central and auxiliary slots are cut away.

5. A method of making single edged razor blades from double edged blade strip stock, the method being substantially as hereinbefore described.

6. Razor blade stamping equipment for forming in double edged blade strip stock the central slot for each blade and, parallel to and flanking each central slot, an auxiliary pair of slots.

7. A method of making single edged razor blades which comprises making double edged blades each having a central slot of such width that its longitudinal flanking portions are of only single edged blade width, and cutting through or away the ends of the central slots.

8. Razor blade stamping equipment for forming in double edged blade strip stock central slots of such width as to leave flanking portions of only single edged blade width.