US2593307A

US2593307A - Safety razor

Info

Publication number: US2593307A
Application number: US88155A
Authority: US
Inventors: Jacobsen Edwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-04-18
Filing date: 1949-04-18
Publication date: 1952-04-15
Anticipated expiration: 1969-04-15

Description

April 15, 1952 E. JACOBSEN 2,593,307

SAFETY RAZOR Filed April 18, 1949 2 SHEETS-SHEET l 8 Z l G f Z JNVENTOR. faw/rvdqaoeazw,

Patented Apr. 15, 1952 UNITED STATES PATENT OFFICE This invention relates to safety razors, and is 1 Claim. (CI. 30-52) particularly concerned with means for provid- I ing a tension on the blade of the razor when the blade is disposed in operative relation to the guard and head of the razor.

This application is a companion application to my previously filed applications entitled Safety Razors, Serial Nos. 715,325, now abandoned, and 723,355, filed December 10, 1946, and January 21, 1947, respectively, and partakes of the objects and advantages of the inventions set forth therein. The primary concern of my prior inventions and of the invention of the present application is to provide for a tension of the fibers of the metal blade in a direction normal to the cutting edge thereof. I have found that whilea simple transverse tension applied to the bladewhile disposed in a plane surface is advantageous, the shaving operation is enhanced by disposing the blade in an arcuate plane during the shaving operation. In my previous application Serial No. 723,355 a stressing of the blade while disposed in a desired arcuate plane was provided for by the use of a perforated blade, the perforations of which were engaged by tensioning projections. It is among the objects of the present invention to provide for the tensioning of a razor blade in a direction normal to the cutting edge thereof without requiring any perforations of the blade and without the use of projecting tensioning means which engage such perforations. In the present invention tensioning of the blade is provided for by a novel and improved coaction between the substantially conventional safety razor head and equally substantially conventional guard, both of which cooperate with the blade to tension the same transversely while providing a desirable transverse curvature for the blade during the shaving operation. By virtue of the present invention it is possible to provide the desired tension and curvature without resorting to perforations of the blade and without requiring the use of tensioning projections on either the head or the guard. It is thus an important feature of the present invention to provide for the desired tension and curvature of the blade in a safety razor of conventional design.

The blade of the present invention is char-'.

acterizedby the provision of a shoulder adjacent the cutting edge which is engageable by theouter edge of the head and/or the guard so as to apply an outward tension to the blade adjacent. its cutting edge. When such a blade is disposed between the conforming concave and convex surfaces of a conventional pair of cooperating heads and guards it will be stressed in tension normal to the cutting edge, and will at the same time be flexed into the desired transverse curvature.

In the preferred form of the invention here shown as illustrative of the basic inventive concept, the head is shown as having normal transverse curvatures in excess of the normal curvature of the cooperating surface of the guard. Upon the application of pressure for drawing the head towards the guard there will be a sliding action of the head edge with respect to the guard,

.1 and such sliding movement is utilized in applying the transverse tension to the blade. .The blade of the present form of the invention is provided with a shoulder extending parallel to the cutting edge of the blade. The location of the shoulder with respect to the edge of the head is such that the edge of the head will engage the shoulder of the blade to apply the stressing tension thereto as an incident to the tightening of the head against the guard. In the preferred form of the invention here shown the blade is shown as provided with shoulders on opposite edges of the blade, so that a transverse tension is applied by the elongation of the distance between the opposite edges of the head resulting from the flexing of the head to conform to the curvature of the guard. The present embodiment of the invention further provides parallel opposite shoulders adjacent each cutting edge of the blade so that the outward stretching of the blade to apply the desired tension. is the result of the action of both the head and the guard. 7 It will be understood of course that the invention is not limited to the exact structure here shown by way of illustration. The principles of the present invention will be equally applicable to a blade having a single cutting edge and the shoulders may be applied to either the tophead engaging surface of the blade or to the lower guard engaging surface only. Y

With the above scope of the present invention in mind, reference to the accompanying draw-' ings may be had, in which:

Figure 1 is a vertical transverse section of my preferred form, of the invention showing the parts assembled in operative position.

Fig. 2 is a similar view showing the parts assembled prior to the applicationof tension.

Fig. 3 is a side elevation .ofa modified form of razor embodying the present invention. v Fig. 4 is a top plan view of the blade of the present invention for use with the head and guard of Figs. 1 and 2.

Fig. 5 is a detailed section taken on line 5--5 Of Fig. l.

Fig. 6 is a top plan view of a blade designed for use in the razor of Fig. 3.

Fig. 7 is a top plan view illustrating a modified form of shoulder for use in the blades of Figs. 4 and 6.

Fig. 8 is a detailed section taken on the lines 8-8 of Fig. 7.

Referring more particularly to the drawing, the numeral l indicates the blade, which in the form of the invention here illustrated is a double edged blade formed of thin flexible steel. In conformity with conventional practice the blade is of substantially rectangular form, each elongated side edge being formed with a cutting edge 2. As hereinbefore suggested, the invention is in no way limited to the exact shape and configuration of the blade here depicted. Obviously, other blade shapes may be used in applying the present invention of other types of safety razors. In that form of the invention shown in Figs. 1 to 6, in-

. elusive, the central body of the blade is of uniform thickness while the edges are of greater thickness, forming a shoulder 3 which extends along each side of the blade parallel to the cutting edge 2. In this form of the invention the body of the blade is of uniform minimum thickness while the edge portions are extended outwardly from the body on both sides and at both edges. The shoulder 3 formed by the thickened edge portion of the blade is an abrupt shoulder, its inner surface lying at an angle normal to the plane of the body portion of the blade.

In that form of the invention shown in Figs. 1 and 2 the central portion of the blade body is formed with an aperture 4 by which the blade I is centered between the guard 5 and the head 6. The razor of Figs. 1 and 2 is shown as having a conventional internally threaded handle 1 which threadedly engages an externally threaded central stud 8 carried by the head 6. As illustrated in Fig. 2 the head 6 has a normal concave-convex curvature and is formed to be sprung from such normal curvature to lie against the guard with a modified curvature of the same type as shown in Fig. 1. Conventional heads for razors of this type are now formed with a slight degree of flexibility which may be adequate for the present purpose; however, in the present case it is deemed preferable to provide a greater degree of flexibility by the provision of undercut circular recesses to facilitate the springing action of the head.

It, will also be noted from Fig. 2 that the guard 5 is formed with a more modified concavo-oonvex curvature disposed opposite to the curvature'of the head 6. The guard 5 is, like the head 6, adapted to flex under the application of pressure and such flexing is facilitatedby the undercut relief recesses as shown. The blade engaging edges of the guard 5 are indicated by the numeral l0 and are disposed in opposite parallel relation to blade engaging edges 9 of the head 6. As shown in Fig. 2 the edges 9 and I0 lie in parallel superposed relation when the head and guard are in their normal unstressed relation. In such position the blade lies between the guard and head, thejcutting edge of the blade extending in parallel relation'b'eyond the edges 9 and It. 'In such position the shoulders 3 are also positionedbeyond and parallel to the edges 9 and ID.

In securing the parts for the shaving operation the internal threads of the handle 'Iengage the threads of the stud 8 and rotation of the handle will draw the head down against'the guard whereby both guard and head will be .fiexed wardlyfwith the said edge portions disposeolii'i'a from their normal extreme curvature as shown in Fig. 2 to their more extended position as shown in Fig. 1. During such drawing together of the guard and head it will be seen that in modifying the curvature thereof the distance separating the parallel edges 9 and the distance separating the parallel edges I!) will be increased. In other words, the chords subtending the arcs of curvature will lengthen. In such lengthening of the chords the edges 9 and ill will be moved outwardly to engage the shoulders 3 (as shown in Fig. 1), thus stressing the blade in transverse tension normal to the cutting edges 2 thereof.

'Since the pre-set normal curvature of the head is greater than that of the guard the final relation of the guard and head is with a slight curvature, which curvature will be imparted to the blade to provide for its desired curvature as an incident to'the stressing of the blade.

In that form of the invention as shown in Fig. 3 the head I3 is drawn down against the guard [2 by means of a stirrup bar M. The normal curvatures of the head and guard are as indicated in Fig. 2", and the modification of such curvatures performs the same stressing of the blade as mentioned in connection with Fig. 1. However, with the use of an external securing member, such as the stirrup l4, no central aligning aperture of the blade is required. The blade suitable for use in the razor of Fig. 3 is indicated in Fig. 6 the shoulders 3 of which perform in the same manner as the shoulders 3 of the blade used in Figs. 1 and 2 and disclosed in Figs. 4 and 5.

A modified form of blade for use in either form of razor is indicated in Figs. 7 and'8. ,Inthat form of the blade of the present invention the shoulder 3 parallel to the edge 2 is formed by means of a groove H parallel to the edge and shoulder. By the use of the blade of Figs. '7 and 8 no thickening of the blade edges as shown in Fig. 5 is required and the shoulder 3 may be rolled into the blade edge in an economical fashion. It will be obvious that in the operation of the invention the shoulder 3 of the blade of Figs. 7 and 8 will function in like manner to provide tensioning of the blade as an incident to;

the clamping and transverse. curving thereof. From the foregoing it will be seen that the present invention provides a new and improved razor and a new and improved blade for use in such razor or for use in conventional razors now on the market. By the use of the present invention the blade will be retained in desired transverse curvature while subjected to the desired transverse stressing of the blade .fibers in a direction normal to the cutting edge of the blade. Numerous changes and modifications of the invention may be resorted to without departing from the invention as outlined in the appended claim.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A razor and blade assembly comprising: a blade having a pair of cutting edges along parallel edges, and shoulders adjacent said cutting edges on both upper and lower faces of said" blade, a razor guard member on'which said blade is adapted to be laid with edge portions of said guard engaging and supporting said blade-just inwardly from said shoulders, said guard being of a resilient character and normally springing upplane above the central portion of said guard which connects said edge portions, a resilient arcuate head having wing portions which nor- 5 mally incline downwardly at a substantial angle from the middle connecting portion of said head, means forjmounting said head on said guard with said blade resting on said guard edge portions and with said head wing portions engaging said blade atgfpoints inwardly from said shoulders, said mounting means being adapted to draw said head downwardly relative to said guard thereby compressing said blade between said guard edge portions and said head wing portions and flexing said guard; said blades, and said head so as to shift saidedge portions and said wing portions lateraliy towards and into contact with said shouldersfiwhile arching said guard and said blade transversely and pressurably applying said guard 15 edge portions and said head wing portions outwardly against said blade shoulders to apply ten- 6 sion to said blade and stress the blade in a direction normal to saidoutting edges throughout the length of the latterQ EDWIN JACOBSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED S 'ITATES PATENTS Number Name Date 1,489,419 Beechlyn Apr. 8, 1924 1,600,922 Berger: Sept. 21, 1926 1,886,238 Sonny'- Nov. 1, 1932 2,128,772 Green Aug. 30, 1938 2,241,986 Driess May 13, 1941 2,314,564 Testi Mar. 23, 1943 2,321,350

Ardner June 8, 1943