US2364236A

US2364236A - Safety razor blade

Info

Publication number: US2364236A
Application number: US523005A
Authority: US
Inventors: Muros Joseph
Original assignee: Gillette Safety Razor Co
Current assignee: Gillette Co LLC
Priority date: 1944-02-19
Filing date: 1944-02-19
Publication date: 1944-12-05
Anticipated expiration: 1961-12-05

Description

Dec. 5, 1944.

J. MUROS SAFETY RAZOR BLADE Filed Feb. 19, 1944 JO/J e 01: Mara/.1, INVENTOR.

Patented Dec. 5, 1944 SAFETY RAZOR- BLADE Joseph Muros, Cambridge, Mass., assignor to Gillette Safety Razor Company, Boston, Mass., a corporation of Delaware Application February 19, 1944, Serial No. 523,005

Claims.

This invention relates to safety razor blades and consists in an improved blade of the thin, flexible, open-end type.

Open-end razor blades, that is to say, blades having two sharpened side-portions connected at one end only by a transverse flexible hinge portion, have the advantage that they may be presented in shaving position by endwise movements between the blade-clamping members of the safety razor and are thus adapted for use in safety razors wherein the blade-clamping members are permanently connected by means permitting only a limited separation. Blades of this type may, of course, be used like any other blades in razors wherein the cap and guard members are not permanently connected.

It has been appreciated for some time that in safety razors wherein the blade is transversely It should be understood that in deflecting the hinge portion of the blade it is desirable to maintain to some degree at least the resilient characteristics of the tempered steel from which the blade is formed. Desirable results are secured,

flexed when it is clamped in shaving position, as

in the Gillette type of safety razor, the two side portions of an open-end blade and the shaving edges thereof are sometimes deflected out of their normal relations. While the two sharpened longitudinal edges may be disposed accurately in parallel relation when the blade is initially formed, it sometimes happens that when the blade is flexed the two edges are found to diverge toward the open end of the blade. This is partly due to the fact that the transverse hinge portion at the solid end of the blade has a restraining effect on the two side portions which is entirely absent at the open end of the blade. This difference in structure and behavior and possibly other reasons result at times in a departure from parallelism of the two sharpened cutting edges of the blade. Such variation detracts from the precision of the assembled razor, producing variations in the degree of edge exposure of the blade and may even result in a dangerous degree of edge exposure.

I have discovered that the structure and performance of open-end blades may be improved by initially compensating for the possible divergence of the blade edges occurring when the blade is transversely flexed. I have further discovered that this may be done by permanently deflecting the hinge portion at one end of the blade through a small angle from the plane of the blade. By thus shaping the blade and preferably by causing the deflected hinge portion to be demarked or set off from the body of the blade by lines inclined to the axis of the blade, I impart to the blade a pronounced tendency in its side portions to approach each other or converge at the open end of the blade when the however, even if the hinge portion is annealed to som extent.

The line of deflection of the hinge, or rather the deflected area of the hinge, is determined by lines converging inwardly toward the major axis of the blade. For example, these lines of demarcation may make an angle of to to the major axis of the blade and within reasonable limits the more these lines of demarcation depart from a position the more pronounced is the effect of the deflected hinge portion when the blade is flexed.

The hinge portion has been described as being permanently deflected from the plane of the blade through a small angle and by this is meant an angle in the order of 3 to 6. Such an angle is hardly detectable in the blade. It temporarily disappears when the blade is subjected to normal pressure in a stack of blades and does not in any way interfere with mechanically handling the blades or discharging them from a blade magazine.

.Another advantage incident to the blade of my invention is that it provides the user with a convenient expedient for securing either a normal shave or a close shave with a fully clamped razor. Ordinarily the blade will be presented to the razor with its hinge deflected in the same sense in which the blade is to be transversely flexed, that is to say, if the blade is to be flexed to present an upwardly convex face, the blade will be presented so that the hinge portion is deflected downwardly, and under these circumstances the side portions of the blade will tend to converge or approach each other as already explained. On the other hand by presenting the blade with its hinge deflected in an opposite sense from that in which the blade is to be deflected the step of deflecting the blade will cause the side portions thereof to diverge or separate, and this, of course, will increase the edge exposure of the blade edge and give the user a close shave.

These and other features of the invention will be Fig. 1 is a plan view of the blade on an enlarged scale;

Fig. 2 is a view in side elevation;

Fig. 3 is a view in perspective showing the blade as flexed upon the guard member of a safety razor: and

Fig. 4 is a similar view showing the blade in inverted position as compared to Fig. 3.

The invention as herein shown is embodied in a blade of the Well-known Gillette type but it is not by any means restricted in its application to that or to any particular type of blade but, with suitable modifications, may be embodied in any thin, flexible, open-end blade.

The blade herein shown is generallyrectangular in outline, having reentrant corner recesses an opposite sense from that in which flexing of the blade upon the guard member is to take place.

Under these conditions it will be found that when the blade is flexed a tendency is imparted to its side portions to diverge or to separate at the open end of the blade. This tendency, kept within bounds, isuseful in providing the user with means for securing a close shave as a result of increased edge exposure but alwayswith the blade securely clamped in the razor. Heretofore, the only convenient way of securing an edge exposure greater than normal has been to release the clamping pressure on the blade, and while this is effective for the desired purpose, it necessitates the risk of shaving with a razor in which the head is.not reliably clamped and maintained in definite angularrelation.

The slot l3 terminates at its inner end in a curved enlargement I 4 which defines the inner boundary of the hinge portion I 2. The hinge portion is set off from the body of the blade by two outwardly diverging lines 15 which run from the end of the enlargement [4 to the reentrant recesses at that end of the blade. The deflection of the hinge l2 on the lines [5' is in the order of 3 to 6 and, as already stated, it is important to maintain the tempered resiliency of the deflected hinge.

In Fig. 3 is shown the guard or blade-supporting member 20 of a safety razor having an upwardly convex surface on which the blade is supported and over which it is transversely flexed as it would be when clamped in the complete razor. This figure also shows in dotted lines a blade-locating rib l8 which is ordinarily a part of the cap member of the razor and which serves to locate the blade accurately in shaving position. When the blade of my invention" is flexed as suggested I in Fig. 3, the side portions I0 and II tend .to converge on approach each other at the open end of the blade. Thi converging tendency may be arrested by the rib l8 which thus acts as a positive stop and may be shapedso as to arrest the side portions of the blade in gauged relation in which their sharpened edges lie exactly parallel. It Will be understood that the converging tendency thus imparted to the side portions Ill and II of the blade completely compensates for any tendency of the side portions of the blade to spread from any cause whatever, and insures the user of an accurate shaving instrument having a uniform degree of edge exposure throughout its entire length.

In Fig. 4-the blade is shown in a reverse position upon the guard member 20, that is to say, the hinge portion I2 isdeflected upwardly and in The blade of my invention may be produced on process of manufacture bythe additional step of engaging the hinge portion of the finished blade between heated plates and imparting the desired deflection to the heated portion. This step may be carried out rapidly and conveniently without impairing the temper andresiliency of the hinge portion to any unsuitable degree.

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

1. An open-end'blade for safety razors, having side portions and. a solid, flexible transverse hinge at one end, the side portions being spaced apart at the other end of the blade and having sharpened outer edges, the outer end of said solid hinge being permanently deflected from the plane of the blade through a small angle.

2. An open-end flexible blade for safety razors, having a solid hinge portion at one end permanently deflected from the plane-of the blade through a small angle, and spaced side portions projecting from the hinge portion with parallel sharpened edges and tending to converge or diverge at their outer ends when the blade as a whole is flexed transversely.

3. An open-end flexible blade for safety razors, having spaced side-portions, a solid flexible hinge set off from the side portions bylines-inclined to the axis of the blade and permanentlydefiected from the plane of the blade through a small angle. 4. lAn open-end blade for safety razors, having a thin, flexible body divided into similar. side portions-by a medial slot; and a transversehinge at one end'of the blade definedby lines'converging inwardly, andperrnanently deflected'through an angle'of less than 6 to-the plane of the blade.

5. An open-end blade forsafetyrazors, having a thin flexible body generallyrectangular-inoutline, and elongated unsharpened"endportions-clefined by reentrant corner recesses, the body of the blade being" divided by a medial slot into two similar edge-bearing side portions, and apermanently deflected hinge portion connecting the side portions-at one end of the blade;- and being corner recesses tothesaid medial slot.

Y JOSEPH MURO'S. Y