PATENT SPECIFICATION

Application Date: Dec. 1, 1931. No, 33,273/31. Complete Accepted: Oct. 6, 1932.

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COMPLETE SPECIFICATION. Improvements in Safety Razor Blades

381,391

I, Adolf Lübbeutsmeier, of 15, Sternstrasse, Barmen, Germany, of German nationality, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement :—

This invention relates to a flexible leaf blade for safety razors. Such blades are clamped for use in a frame. By tightening up an abutment to a greater or less extent by means of the handle of the razor, the blade is pressed more or less firmly against the comb or guard of the razor. Under these circumstances, the cutting edges of the blade are at a greater or less distance from the comb according to the degree of bending of the blade.

If the abutment is firmly tightened up, the cutting edges bear comparatively closely on the guard. In such a case shaving is particularly safe, since the blade is firmly clamped in the razor frame, and the user will not cut himself. There is, however, the disadvantage that the blade does not catch the hair particularly well. If on the other hand the abutment is moved away from the guard, the cutting edges of the blade rise off the guard in consequence of the elastic properties of the blade. In this case the blade catches the beard particularly well. There is, however, the disadvantage that the blade is liable to exit into the skin, since it vibrates during the shaving.

In the course of manufacture the blades are stamped out of a long steel strip, or broken after the hardening of this strip at a so-called breaking mark. Since the steel strip is produced by rolling, the fibres of the metal extend in the longitudinal direction in the strip, and therefore in the blades made therefrom, and the stiffness of the blade in the transverse direction is comparatively small.

According to the invention these disadvantages are obviated by producing small shallow indentations throughout substantially the entire surface of the blade by hammering or by pressure. This provides the blade with a fibrous structure which is to an appreciable extent transverse to the longitudinal fibres produced by rolling, with the result that the blade can be firmly clamped between the parts of the razor frame, with the cutting edge far enough away from the guard comb to enable the individual hairs to be reliably seized, the razor blade being so well stiffened in the transverse direction that even in the event of it not bearing completely upon the comb it is not so liable to vibrate, and therefore to cut into the skin.

It has already been proposed to provide stamped points projecting from one side of a safety razor blade in or near its longitudinal central axis for the purpose of holding fast the central portion of the blade, and to emboss safety razor blades, to enable them to be secured firmly to holders provided with corresponding recesses or projections, and it has been noted that the embossing serves to strengthen the blade.

Longitudinal, transverse or oblique ridges, grooves and corrugations have been adopted for the purpose of acting as guiding means and also of enabling razor blades to be made thinner than would otherwise be possible.

It has also been proposed to provide shallow transverse grooves or channels throughout one or both surfaces of a razor blades, starting behind the cutting edges, to permit the hair and soap to move away clear of the cutting edges.

Relatively large shallow transverse undulations or part-spherical humps have been provided in safety razor blades for the purpose of enabling the cutting edges to be placed in a state of longitudinal tension by gripping the blade in the holder.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which

Figure 1 is a view of a razor blade according to the invention,

Figure 2 is a section on the line II—II in Fig. 1 on a greatly enlarged scale,

Figure 3 is a view of another form of construction of the razor blade according to the invention, and

Figure 4 is a section on the line IV—IV in Fig. 3.

According to the invention a flexible leaf blade b is stiffened by hammering or pressing throughout the entire rectangular area extending across the blade from one cutting edge to the other in such a way that small shallow indentations are produced on one side, and corresponding convexities a on the other. At c is indicated how the indentations are separated from one another by clear boundary lines. Such a blade is immediately ready for use in shaving, and has the advantage hereinbefore indicated that the blade can be firmly clamped between the parts of the razor frame, but nevertheless cuts satisfactorily, and no vibrations of the blade take place.

In a further particularly advantageous constructional form the indentations and the projections a are partly eliminated again by pressure or rolling, as indicated at a′. At c′ it will be seen how the lines of separation originally pressed out have been flattened so that they no longer stand out so sharply. Owing to the partial elimination of the projections a, and the flattening of the lines of separation c, a further stiffening of the blade in the transverse direction is produced.

Since the blade according to the invention is more resistant to fracture it is possible to manufacture it from a cheaper material, which otherwise could not be employed at all for the manufacture of razor blades of such a high quality. In this way it is possible to reduce the price of a razor blade. A further advantage resides in the fact that the hardness can be increased, by a lower starting temperature for example, without running any risk of the blade breaking. Owing to the greater hardness, however, a better cutting power and a longer cutting life of the blade are obtained, or in other words an improvement in the cutting properties of the blade.

The invention is of course not restricted to blades with fastening holes of the kind illustrated, but can also be employed with particular advantage in the case of those so-called long-hole blades, in which either the fastening holes are connected by means of a slot occupying the entire central portion, or in which, instead of the fastening holes, a slot extending over the central portion of the blade is provided, or in which this slot extends even beyond the region of the outer fastening holes. In such blades with an elongated hole the space e of the blade, located between the outer ends of the slot and the end edge d, is also preferably provided with such pressed or hammered elements, for the purpose of yielding good transverse stiffness of the blade just in the comparatively narrow portion of the blade by which the halves of the blade are held together.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:—

1. A flexible leaf blade for safety razors, characterised by the feature that substantially the whole area of the blade between the cutting edges is stiffened and improved in quality by small shallow indentations produced by hammering or by pressure.

2. A razor blade as claimed in claim 1, characterised by the feature that the pressed indentations or hammer marks are partially eliminated by pressure or rolling, and the blade material thereby further consolidated.

3. A flexible razor blade substantially as hereinbefore described with reference to the accompanying drawings.

Dated this 1st day of December, 1931.

Marks & Clerk.