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Gilette Tech

PatentUS2270388

InventionSafety Razor

FiledTuesday, 9th August 1938

PublishedTuesday, 20th January 1942

InventorSamuel C. Stampleman

OwnerGillette Safety Razor Company

LanguageEnglish

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A PDF version of the original patent can be found here.

Patented Jan. 20, 1942 2,270,388
United States Patent Office
2,270,388 Safety Razor Samuel C. Stampleman, Cohasset, Mass., assignor to Gillette Safety Razor Company, Boston, Mass., a corporation of Delaware Application August 9, 1938. Serial No. 223,893 5 Claims. (Cl. 30—72)

This invention relates to safety razors of the type in which a thin flexible blade is clamped for support between cap and guard members. The present invention relates more particularly to the structure of these members and its general object is to provide a construction in which sheet metal may be utilized as distinguished from the solid swaged or machined constructions heretofore used.

The cap and guard members are relied upon not only for shaping and supporting the thin flexible cutting blade when it is clamped between them for shaving but they determine also the edge exposure of the razor. This is a critical dimension since too great edge exposure renders the razor dangerous and too little exposure renders it uncomfortable and inefficient in shaving. The tolerance limits for edge exposure are in the order of .001 to .002 and it is, consequently, important that the cap and guard should be manufactured with considerable accuracy, and should be of sufficiently rigid construction to maintain their shape without variation during the life of the razor. On account of these considerations it has been the practice heretofore to fashion the cap and guard members from solid stock as by swaging or machining bar stock. Sheet metal has not heretofore been considered entirely satisfactory as a material for these uses. I have discovered, however, that by providing a suitable stiffening configuration I am able to construct from sheet metal of uniform thickness blade-supporting members which answer all the exacting requirements of the razor industry.

As illustrating one useful application of my invention, I have herein shown a safety razor having a sheet metal guard member which is stiffened by the walls of an elongated depression moulded or otherwise formed in the body of the blank and serving to stiffen it in a marked degree against being deformed either longitudinally or transversely. As preferred and as herein shown the depression is made diamond-shaped and utilized for the additional function of receiving the blade-locating rib of the cap. The walls of the recess, moreover, are arranged to converge and are slotted at their end portions to engage the ends of the rib of the cap and so position the cap accurately in the razor assembly.

As a further and optional feature of the invention I propose to supply a face-engaging portion of the guard with transverse grooves or scorings tending to oppose longitudinal slipping of the razor on the face of the user, so obviating or largely reducing a movement of the razor which is likely to result in cutting the user.

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 view in perspective of the complete safety razor.

Fig. 2 is a plan view of the cap member.

Fig. 3 is a view of the cap in longitudinal section on the line 3—3 of Fig. 2.

Fig. 4 is a view of the cap in cross section on the line 4—4 of Fig. 2.

Fig. 5 is a plan view of the guard with its outer face exposed.

Fig. 6 is a plan view of the guard with its inner face exposed.

Fig. 7 is a view of the guard in longitudinal section on the line 7—7, of Fig. 5.

Fig. 8 is a view of the guard in central cross section.

Fig. 9 is a view of the guard in cross section on the line 9—9 of Fig. 5.

Figures 10 and 11 are respective views in cross section and in longitudinal section of the safety razor.

Fig. 12 is a view of the blade, and

Fig. 13 is a cross-sectional view of one side of the safety razor on the line 9—9 of Fig. 5, but on a greatly enlarged scale.

In the safety razor selected to illustrate my invention the cap 10 is rectangular in outline and presents an inner concave blade-engaging surface. The outer surface of the cap is convex and the cap as a whole tapers transversely to­ ward both its marginal edges. It is provided with a central threaded stud 11 and with a centrally disposed elongated upstanding rib 12, designed to engage a slot in the blade and so locate the blade accurately upon the cap. The illustrated razor is designed for use with double edge blades, such for example as the blade 23 shown in Fig. 12. This blade has an elongated slot 24 which fits upon the rib 12 of the cap and is also provided with corner notches. The cap has reinforcing corner lugs 13 which occupy the corner notches of the blade when all parts of the razor are assembled. The cap above described is of more or less conventional design and is not in itself a part of the present invention. While it may be constructed of sheet metal it is not so shown herein.

The guard member 14, herein shown as designed to cooperate with the cap 10, is, however, of novel construction. It is formed from sheet metal of uniform thickness and its transverse contour is convex so that a blade clamped between it and the concave blade-engaging surface of the cap will be held in a condition of transverse curvature. The guard is also rectangular in outline, being somewhat wider than the cap. The guard has a flat body portion which merges outwardly on both sides into concave intermediate zones or sections 15. Each of these concave sections is provided, for the sake of lightness, with a pair of elongated recesses 16, spaced from each other and from the ends of the guard. Each of the concave zones 15 in turn merges into an unperforated downturned flange 17. The juncture between the concave sections 15 and the downturned flanges 17 comprise outwardly convex longitudinal shoulders and in these shoulders are placed a series of transverse corrugations or scored lines 18. The scoring 18 is located upon the guard immediately beyond the cutting edge of the razor blade and contacts the face of the user with a tendency to prevent slipping of the razor in a direction parallel to the blade edge.

The guard member 14 is also provided with a large centrally disposed diamond-shaped depression 19 defined by upstanding walls which have the effect of stiffening the guard against bending longitudinally or transversely. The edge walls of the depressions act in effect as reinforcing ribs for the sheet metal of the guard, and are extremely effective in stiffening the guard member, causing it to maintain its shape in use and preventing distortion even if dropped. The walls of the depression converge symmetrically toward opposite ends of the guard. A central hole 20 for the reception of the threaded shank 11 of the cap is provided in the bottom wall of the depression 19. The walls of the depression are, moreover, slotted where they converge at each end or vertex to receive and fit upon the ends of the rib 12 of the cap and so locate the cap positively in shaving relation with respect to the guard.

The thin flexible sheet steel blade 23 used in the razor has already been referred to. A blade of conventional shape is shown in Fig. 12 but any blade perforated to fit accurately upon the rib 12 or to engage its ends would be suitable for use in the described assembly. The razor includes a handle 25 internally threaded to receive the threaded stem 11 on the cap and rotatable to clamp the cap and guard members with the blade 23 between them.

It will be understood that the cap and guard members determine by their edges the edge exposure of the blade as suggested in Fig. 13. They must between them be capable of exerting sufficient clamping pressure upon the blade to hold it securely in the proper predetermined shaving position and to support the blade on both sides adjacent to its shaving edges. The cap 10 above described is naturally rigid on account of its solid construction and the sheet metal guard 14 by reason of its configuration has sufficient rigidity imparted to it for a satisfactory performance of its functions. A flat sheet metal member would not be rigid enough to serve the purpose of the novel guard herein disclosed and it would have to be further weakened by slotting to receive the rib 12. In accordance with my invention, however, the metal displaced to make room for the rib is utilized to stiffen the guard and so three functions are served by a single expedient, that is, by displacing metal to form the diamond-shaped depression 19, space is provided for the rib of the cap, upstanding walls are formed which provide stiffness to the whole structure of the guard itself and upright slots are provided by which the cap is located by the fitting of its rib 12 into the slots.

While I have shown my invention as embodied in the guard member, it would be within the scope of the invention to construct the cap of sheet metal and stiffen it by a walled depression within the terms of the appended claims.

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

1. A safety razor comprising cap and guard members, one having a projecting blade-locating rib and the other comprising a sheet metal body having a depression in its blade-engaging face defined by relatively thin, sheet metal side walls which stiffen the guard against bending and converge toward both ends of the guard into engagement with the rib of the other member for accurately locating the same.

2. A safety razor comprising a cap having a projecting blade-locating rib, and a sheet metal guard member having an elongated shallow dome moulded therein and providing a recess for receiving the rib of the cap with clearance throughout the major portion of its length and surrounding sheet metal walls which stiffen the guard member against bending and converge substantially into engagement with the ends of the rib of the cap.

3. A safety razor comprising a cap having a concave blade-engaging face with a projecting rib therein, and a sheet metal guard having a convex blade-engaging face in which is moulded a diamond-shaped depression having guard stiffening walls of sheet metal which engage said rib at its ends to locate the cap and diverge toward the center of the guard into spaced relation with respect to said rib.

4. A safety razor having, in combination, a ribbed cap, and a sheet metal guard having a depression therein formed by endwise converging walls of sheet metal, the vertices of said walls being slotted to provide rib-engaging stops for locating the cap by fitting the ends of the rib while the body of the depression receives the intermediate portion of the rib with clearance.

5. In a safety razor, a ribbed cap and a guard of pressed sheet metal having a transversely convex blade-shaping face, downturned marginal flanges, a central perforation, and a diamond-shaped rib-receiving depression sunk symmetrically in its major axis with its widest part enclosing said depression and its ends provided with slots extending through the walls of the depression and into the surrounding metal of the guard, for locating the cap by engaging the ends of its rib.

Samuel C. Stampleman.