US2045184A - Safety razor blade - Google Patents

Description

SAFETY RAZOR BLADE Filed March '7, 1934 A TTORNEY Patented June 23, 1936 UNITED STATES SAFETY RAZOR BLADE Henry J. Gaisman, Hartsdale, N. Y., assignor to Gillette Safety Razor Company, Boston, Mass, a corporation of Delaware Application March 7, 1934, Serial No. 714,462

4 Claims.

This invention relates to safety razors of the type in which a thin flexible blade is removably secured in a holder comprising blade-clamping members which are shaped to impart a pronounced transverse curvature to the blade and support it for shaving upon opposite sides of its cutting edge. More particularly the invention consists in a novel safety razor blade characterized by one or more transverse corrugations therein tending to stiffen the blade against transverse flexing and to reinforce it against breakage.

The Gillette razor exemplifies one type of razor in which the blade of my invention may be used with advantage and for convenience the invention will be described in its application to blades of that make. In such safety razors it is customary to regulate the degree of edge exposure of the blade by varying the clamping pressure thereon, that is to say, when the blade is fully flexed and the clamping members firmly engaged with the blade its edge exposure is at a minimum. When the user desires to increase the edge exposure this may be done by slightly releasing the clamping members and permitting the blade to approach slightly its normal flat condition. Under the latter circumstances it sometimes happens that the pressure of the flexed blade upon the clamping members is insufficient to prevent relative toand-fro movement thereof with the result that the shaving edge of the razor tends to chatter and this of course is to the great discomfort of the user. In accordance with the present invention I propose to stiffen the blade in its transverse flexing by providing one or more corrugations extending transversely of the body of the blade and, while still resilient as a whole, tending in -a pronounced degree to stiffen the blade transversely. When such a blade is used in a razor wherein the clamping pressure has been relaxed sufficiently to increase substantially the edge exposure of the blade, the flexed blade will exert pressure adequate to maintain the clamping members firmly against displacement and so obviate the possibility of blade chattering.

My invention may be applied with particular advantage to flexible blades provided with internal apertures or slots for the purpose of registering them accurately upon blade-locating projections in the razor or of providing flexing hinges in the blade distinct from the cutting edge portions thereof. Such apertures tend, of course, to increase the flexibility of the blade and where a blade is provided with anelongated blade-locating slot in its major axis the stifiness of the blade is very substantially reduced and the flexing pressure in the safety razor is so'small as toinvite chattering of the blade. Such a blade may be advantageously provided with transverse corrugations located beyond the ends of the blade-' locating aperture, and thereby rendered as stiff or stiffer than anintegral blade of the same thickness of steel.

An important advantage incident'to the construction of my inventionis that the transverse corrugations serve the additional function of safeguarding the blade and reinforcing it against breakage in general and against longitudinal cracking in particular. In this instance too, my invention may be applied with particular advantage to a blade equipped with an elongated bladelocating aperture, since in such a blade the ef-. fective area of steel liable to fracture is reduced nearly to the limit of safety.

These and other features of my 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 blade constructed in accordance with my invention;

Fig. 2 is a view in longitudinal section on the line 2-2 of Fig. 1;

Fig. 3 is a similar view of a blade of somewhat modified construction;

Fig. 4 is a plan view of a blade having a modified form of transverse corrugation;

Fig. 5 is a view in longitudinal cross-section of the blade shown in Fig. 4 on the line 5-5; and

Fig. 6 is a view in perspective of a safety razor having a blade clamped in position of transverse curvature for shaving, a portion of the cap being shown as broken away.

It will be understood that my invention may be incorporated in any safety razor blade of the thin flexible type above discussed. The blade l0 shown in Fig. l is one example of such blade which is now being manufactured under commercial conditions. It has a thin flexible steel body 0.006" or more in thickness and is sharpened at both longitudinal edges for cutting. It is provided at each corner with a reentrant recess and these define in the blade elongated unsharpened end portions [2. The blade is also provided with an internal aperture in the shape of an elongated slot M having spaced transverse enlargements and shaped to fit accurately upon the bladelocating projections of the razor in which it is intended for use.

As shown in Figs. 1 and 2 the end portions ll of the blade are provided with shallow transverse corrugations I6. These corrugations are located symmetrically in the blade intersecting its major axis in the space between the ends of the bladelocating slot I4 and the outer edges of the blade and extending continuously across each end portion. As shown in Figs. 1 and 2 the corrugations I6 are both concave upwardly but if desired they may be oppositely arranged as shown in Fig. 3 wherein one corrugation I6 is concave upwardly and the other corrugation I8 is concave downwardly.

It will be seen that the reentrant corner recesses of the blade and the internal aperture or slot I4 define the end portions I2 which constitute substantially flexing hinges located entirely beyond the cutting edges of the blade. When the blade is clamped in the safety razor the bending stresses are accordingly concentrated in these flexing hinges. The eifect of the transverse corrugations I6 is to stiffen the hinges in their transverse bending without at all preventing such bending. The corrugations have the further effect of tending to reinforce that portion of the blade which is most likely to fracture, that is to say the portion of the blade between the ends of the aperture or slot I4 and the outer edges of the elongated end portions I2.

In Figs. 4 and 5 is shown another blade 20 having end portions 22 and a blade-locating aperture 24 of the shape already described. This blade is provided with transverse corrugations 26 in its flexing hinges or end portions 22 which are similar to those already described except that they do not extend entirely across the end portions 22 but terminate within the boundaries thereof. The corrugations 26 are shown in Figs. 4 and 5 as being both upwardly concave but may be formed in opposite directions if desired.

In Fig. 6 is shown a safety razor of the Gillettetype comprising a cap 30 and a guard 32 with cooperating faces shaped to engage the blade I0 and impart a transverse curvature thereto and to support the flexed blade on both sides of its cutting edge. In this view the flexed condition of the blade and particularly of its flexing hinge portion I2 with its corrugation I6 is well shown. The cap 30 and guard 32 are held together by a threaded stud which extends from the cap into the handle member 34. For minimum edge exposure the handle is fully tightened, but in order to secure an increased edge exposure the cap and guard may be permitted to separate slightly. It is under these conditions that the stilf characteristics of my novel blade are to be particularly and favorably observed in a stable and chatter-free razor assembly.

Having thus disclosed my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. A flexible, normally flat, safety razor blade having a blade-locating slot therein terminating short of the ends of the blade, and transversely disposed resilient corrugations of less length than the blade width located respectively between each end of the slot and the end of the razor blade.

2. A thin, flexible, normally flat, safety razor blade having reentrant recesses in its corners which define centrally disposed unsharpened end portions, and an elongated internal aperture terminating short of said end portions and forming therein flexing hinges in the blade, said hinges having resilient transversely disposed corrugations therein stiffening the blade in transverse flexing.

3. A normally flat safety razor blade having cutting edges, a blade-locating aperture substantially as long as its cutting edges and elongated end portions constituting flexing hinges located entirely beyond the ends of its cutting edges, said flexing hinges being stifiened in flexing by resilient corrugations located therein transversely of the blade.

4. A flexible double edged safety razor blade having a centrally disposed slot at least as long as the cutting edges of the blade and flexing hinges located beyond the ends of the slot, whereby the cutting edge portions of the blade are relieved of stress when the blade is flexed, and a transverse resilient corrugation in each of the hinges for increasing the resilient resistance of the hinges to flexing.

HENRY J. GAISMAN.

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