US2362498A - Safety razor blade - Google Patents

Description

Nov. 14, 1944. J u os 2,362,498

SAFETY RAZOR BLADE Filed Jan. 5, 1944 Patented Nov. 14, 1944 SAFETY RAZOR BLADE Joseph Muros, Cambridge, Mass. assignor to Gillette Safety Razor Company, Boston, Mass., a

corporation of Delaware AppllcationJanuary 5, 1944, Serial No. 517,093

6 Claims.

This invention consists in improvements in safety razor blades of the open-end type, that is to say, blades having two side portions separated by a longitudinal slot opening through one end of the blade and connected by a solid hinge portion at the other end of the blade. In one aspect the invention consists in an open-end blade preformed so that its side portions are maintained in the angular relation best adapting them for use in safety razors of the well-known Gillette type wherein cooperating blade-clamping members transversely flex and hold the blade for shaving.

Open-end blades have the advantage that they are adapted for use both in safety razors in which the blade-clamping members are wholly detachable and in safety razors where the blade-clamping members are connected for limited separation only. When used in razors of the latter type an open-end blade may be slipped endwise into shaving position between the cooperating bladeclamping members of the razor while the latter remain connected and are therefore not susceptible to displacement or loss as loose parts.

Heretofore it has been found that open-end blades tend to spring apart at their open end or fail to draw in at their open-end to the same extent that they do at their closed end. The result is that in using open-end blades heretofore constructed uneven edge exposure is likely to occur when the blade is clamped in shaving position. This variation is sometimes sufficient to cause the outer corners of the blade to be dangerous to the user and in any case it detracts from the safety razor as an instrument of precision and causes different shaving action to occur at difierent places along the sharpened edges of the blade.

The variations in edge exposure above discussed are obviated and certain important advantages achieved by constructing an open-end blade in accordance with the present invention, that is to say, by including therein a hinge portion connecting the two side portions of the blade at one end thereof and disposed as a flange extending in a plane substantially at right angles to the major axis of the blade. Preferably and as herein shown the flange constituting the hinge portion may be annealed and softened so that it may be flexed without danger of cracking, while the remainder of the blade is tempered and hardened for cutting and so made somewhat more brittle in character.

Another feature of the invention consists in imparting to the upstanding flange of the hinge a concavity in its outer face. The vertex or fold line of the flange and the flange itself are bowed and given an outward concavity and at the same time the free ends of the side portions of the blade are thrown slightly toward each other. The flanged formation of the blade holds them in'that relationship and resiliently opposes any spreading tendency of the free ends of the blade from any cause whatever. The complete blade is thus given a cross-sectional contour of substantially the same shape as that of the blade-clamping faces in the razor in which it is to be used. The flange provides a convenient handle for presenting the blade to the razor and for withdrawing it therefrom. It tends at all times to hold the blade with its free ends slightly contracted so that in presenting the blade to the razor the gauging edges of the side portions may be sprung apart to receive the rib or other bladelocating projections of the razor and these edges are then maintained in gauged position throughout the shaving operation. Thus, in general, I have compensated for all the usual tendencies which might otherwise cause spreading apart of the ends of the blade and insure parallel relation of its shaving edges when clamped in shaving position.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawing, in which:

Fig. 1 is a plan view of a flat blade blank on an enlarged scale;

Fig. 2 is a view in perspective of the blade on the same enlarged scale complete and ready for insertion in a razor; and

Fig. 3 is a plan view on the same scale showing the blade in position upon the cap member of a safety razor.

The blade as shown in Fig. 1 is first outlined in thin sheet steel between .003 and .007" in thickness. It comprises two similar side portions I0 and I I, each having outer sharpened cutting edges I 2 and separated by a central longitudinal slot 53. The slot I 3 opens out through the right-hand end of the blade as shown in Fig. 1 and is provided with a central circular enlargement IQ for the passage of the stem of the cap. The blade is provided with reentrant recesses in all four corners, two of which define an elongated unsharpvmay of the blade which includes the two side the fold line or vertex 16 of the flange I is slightly curved so that the outer face of the flange is outwardly concave. The effect of forming the flange in this manner is to throw the side portions In and H of the blade into angular relation, that is to say, to cause them to converge toward each other in an obtuse angle symmetrically with respect to the axis of the slot l3, and also the free ends of the side portions are thrown toward each' other so that they exhibit a slight longitudinal convergence. They are, of course, resiliently maintained in this pre-formed condition.

In Fig. 3 the blade is shown as placed upon the concave face of the cap member 20 of a safety razor of the Gillette" type. The cap member is rectangular in outline and provided with a pair of short blade-locating ribs 2| in the major axis of its concave face. It has also a threaded stem 22 arranged to pass through the circular enlargement ll of the blade and a corresponding aperture in the guard member, and to make threaded engagement with the handle of the razor. The stem is undercut adjacent to the face of the cap to accommodate the width of the slot I3 in the blade. A reinforcing lug 23 is provided in each corner of the cap and these are spaced so as to afford clearance for the corners of the blade. The lugs 23 are of slight thickness so that the blade may be presented freely by endwise movement, that is to say, the blade-locating ribs 2| are embraced by the slot". and the end of the blade may be advanced in the undercut portions of the stem 22 continuing to advance until it reaches the symemtrical position shown in Fig. 3. In this movement the inner gauging edges of the side portions l0 and i I hug the outer gauging faces of the blade-locating ribs 2| so that when the blade the convex and concave faces of the cooperating blade-clamping members. It will be further noted that the overall length of the blade is such that its free ends lie wholly within the right-hand end of the cap 20 where they are safe from contact with the fingers of the user during the blade-clamping operation.

From the foregoing description it will be apparent that by pre-forming the open-end blade so that its shape in transverse section remains substantially unchanged in the blade-clamping operation, I have eliminated the tendency to spread that has been heretofore introduced when the blade has been transversely flexed from flat condition for the first timewhen it is clamped in the razor. Further, by imparting an initial convergence to the side portions. which is resiliently maintained in the finished blade, I have provided a force in the blade itself tending to oppose spread from any other cause.

Having thus disclosed my invention and described in detail one preferred embodiment thereof I claim as new and desire to secure by Letters Patent:

1. An open-end blade comprising side portions of similar shape separated by a central longitudinal slot opening through one end of the blade, and a hinge portion connecting the side portions at the other end of the blade and disposed in a plane at substantially right angles to the axis of said longitudinal slot.

2. An open-end blade comprising elongated side portions sharpened at their outer edges and separated by a central longitudinal slot opening through one end of the blade, and a, transverse upstanding flange at the other end of the blade connecting said side portions and maintaining them in angular relation to each other.

3. An open-end blade comprising sharpened side portions separated by a centra1 longitudinal slot opening through one end of the blade, and an upstanding flange at the other end of the blade extending partially across the ends of the side portions and maintaining them in positions oppositely inclined from said central slot.

4. An open-end blade comprising sharpened side portions separated by a central longitudinal slot opening through one end of the blade, and an upstanding transverse flange at the other end of the blade into which the said slot extends.

5. An open-end blade comprising side portions sharpened at their outer edges and spaced apart by a central longitudinal slot opening through one end of the blade, and an upstanding transverse flange at the other end of the blade connecting the side portions thereof and outwardly concave about an upright axis.

6. An open-end blade comprising side portions sharpened at their outer edges and spaced apart by a central longitudinal slot and a transverse flange erected at the closed end of the blade, holding the side portions at a convergent angle to each other with respect to the axis of the slot and resiliently maintaining the free ends of the side aortiors closer together than the connected ends ereo JOSEPH MUROS.

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