US3735486A

US3735486A - Razor blade with integrated supplemental guard

Info

Publication number: US3735486A
Application number: US00131020A
Authority: US
Inventors: F Risher
Original assignee: Individual
Current assignee: Bank of Virginia
Priority date: 1971-04-05
Filing date: 1971-04-05
Publication date: 1973-05-29
Anticipated expiration: 1990-05-29

Abstract

A razor blade including a supplemental guard in the form of an integral bead positioned in closely spaced, parallel relation to the cutting edge for coaction with the conventional razor guard to provide rigid skin bearing surfaces bridging the cutting edge. The purpose of the coacting structure is to provide a two point bearing surface, bridging the cutting edge, to thus decrease the instantaneous angle of attack made by the cutting edge with respect to the skin surface as the same is deformed by passage of the conventional razor guard thereacross.

Description

United States Patent 1191 Risher RAZOR BLADE WITH INTEGRATED SUPPLEMENTAL GUARD Frederick L. Risher, P. O. Box 1887, Laurel, Miss. 39440 Filed: Apr. 5, 1971 Appl. No.: 131,020

Inventor:

US. Cl. ..30/78, 30/342, 30/346.58 Int. Cl ..B26b 21/16, B26b 21/54 Field of Search "30/342, 65, 78,

References Cited UNITED STATES PATENTS Merriclt ..30/346.58 x Clausen ....30/346.58 X

O'Connor ..30/78 1451 May 29, 1973 693,524 2/1902 Korn ..30/346.55 X

Primary Examiner-Othell M. Simpson Assistant Examiner-Gary L. Smith Altorney-Colton & Stone [57] ABSTRACT A razor blade including a supplemental guard in the form of an integral bead positioned in closely spaced, parallel relation to the cutting edge for coaction with the conventional razor guard to provide rigid skin bearing surfaces bridging the cutting edge. The purpose of the coacting structure is to provide a two point bearing surface, bridging the cutting edge, to thus decrease the instantaneous angle of attack made by the cutting edge with respect to the skin surface as the same is deformed by passage of the conventional razor guard thereacross.

4 Claims, 6 Drawing Figures PATENTEDNAYZQIQB 3,735,486

SHEET 1 OF 2 FIG. 5

INVENTOR PRIOR ART FREDERICK L. RISHER A'rronmsvg PATENTEDMYZE! I915 7 35,486

SHEET 2 0F 2 5 INVENTOR FREDERICK L. RISHER ATTORNEYS.

RAZOR BLE WITH 1i SUPPLEMENTAL GUARD BACKGROUND OF THE INVENTION Notwithstanding the highly competitive nature of the razor industry and the vast sums spent on research and advertising; the operating characteristics of present day safety razors are virtually identical with those of their predecessors. Although the safety razor has virtually eliminated any risk of serious injury one of its basic design parameters, which is the razor guard or soap bar, has, since the original safety razor development, been largely responsible for the minor skin abrasions and/or nicks which are commonly experienced by even the most experienced shavers. This is due to the fact that the depression of the skin by the razor guard inherently produces a skin roll which follows the guard in its movement across the skin. This skin roll is, of course, flattened out by engagement with the cutting edge of the razor blade as the shaving action occurs. It will thus be appreciated that the shaving action does not occur along a substantially smooth surface but, rather, at the base of the moving skin roll produced by the razor guard. The instantaneous angle of attack defined between the cutting edge of the razor blade and the moving skin surface during a shaving operation is thus quite large as opposed to a theoretical angle of attack which would exist if the skin were an inflexible surface so that the aforementioned skin roll were not produced as a function of a shaving operation.

It is important to note the two, perhaps somewhat subtle, distinctions inhering from the aforementioned skin roll effect and their manner of contributing, independently, to skin abrasions and nicks. The first is the use of the sharp cutting edge to act not only as a shaving edge but, also, as a skin bearing surface to the necessary extent that the same acts to smooth out or flatten the moving skin roll. The cutting edge may thus be considered as akin to a change direction pulley about which the deformed skin surface is deflected as the transition from a rolling to a flattened surface occurs. The blade edge pressure is thus both excessive and improperly applied since the desiderata for a proper shaving operation include a movement of the cutting edge parallel to the skin surface so that the skin surface is not deflected about the cutting edge in the nature of a flexible surface entrained about a change direction pulley. An at least subconscious recognition of this fact is apparent to any shaver who has ever stretched the skin to permit the application of a greater shaving pressure while, concomitantly, reducing the likelihood of skin damage.

The second distinction, that of excessive blade angle, is perhaps more apparent. Assuming, for purposes of illustration, a substantially inflexible shaving surface; then the angle of attack made by the cutting edge with respect to the skin surface as would be determined by the fixed mechanical positionment of the blade and razor guard would approach the ideal condition. Stated difl'erently, present day safety razor manufacturers design the razor guard and blade positioning mechanism so that the most favorable blade angle of attack is positively defined with respect to predetermined conditions such as a specified blade pressure and an assumed angle at which the razor handle is held. It is obvious that there are as many ways to hold a razor and as many pressures to be applied as there are shavers. Consequently, the magnitude of the skin roll which is a function of applied pressure and the individual skin surface cannot be ascertained in advance or compensated for by decreasing the blade angle positionment in the razor. An excessive blade angle is, of course, a primary cause of nicks and minor skin abrasions. This, too, is reflected in the common practice of stretching the skin while shaving. The stretching action achieves the desired effect by providing a second area of skin depression which coacts with the razor guard to provide skin depression areas bridging the cutting edge to thus smooth out the skin surface therebetween and reduce the skin roll following the razor guard so that a reduced blade angle is defined with respect to the skin surface.

Although the problem can be avoided by shaving with a very light touch so that the skin surface is only slightly deformed; as a practical matter this is not done by the general shaving public for a number or reasons which include a psychological belief that a smooth shave cannot be obtained without exerting substantial pressure.

Previous attempts to incorporate some type of a guard with the blade itself have failed to recognize that a guard, integrated with the blade, may be used to coact with the conventional razor guard but, rather, have attempted to rely on either the blade guards, per se, as in U. S. Pat. No. 1,918,856 or an arrangement such as shown in 'U. S. Pat. Nos. 3,505,734 and 3,555,682 wherein the blade cutting edge is, itself, partially covered with a plurality of guard elements thus effectively reducing shaving efficiency as compared with a bare blade.

SUMMARY OF THE INVENTION The basic concept of the invention is to provide a skin bearing surface immediately adjacent the juncture of the blade bevel and the honed portion thereof which will cooperate with a conventional razor guard to provide spaced, non-cutting skin bearing surfaces bridging the blade cutting edge to reduce the skin roll in advance thereof. A reduction of the skin roll thus reduces the likelihood of injury by deflection of the skin approximately about the cutting edge and, also, reduces the angle of attack made by the blade with respect to the skin at the base of the skin roll. The effect may be readily observed by depressing a portion of the skin with one finger and moving the same across the skin surface. The skin roll that follows the moving finger is seen to be quite substantial. If a second finger then be used to depress an adjacent area of the skin and both fingers be moved across the skin surface, it will be observed that the magnitude of'skin roll is greatly reduced for the obvious reason that the flexible surface, depressed at two points, tends to follow a straight line between the lower points of the depressions.

The desired result is achieved by the positionment of a smallbead just rearwardly of the blade cutting edge when considered in the direction of blade movement during a shaving operation. The bead acts as a skin bearing surface on the blade so that the skin surface is deformed about this bead rather than the cutting edge. Additionally, the bead coacts with the razor guard to decrease the skin roll following the razor guard irrespective of the pressure applied at the razor handle. The bead is very small, in the nature of a few thousandths of an inch in height, and is desirably positioned at the juncture of the beveled blade surface and the further beveled surface created by the honing of the cutting edge. It is particularly important that the bead be very small and positioned immediately adjacent the cutting edge of the razor blade for a variety of reasons. Two of the more important of these reasons is to insure that the blade will not require design changes in present methods of packaging exemplified by injector cartridges or conventional blade pack dispensers, and to assure the compatability of the blades with existent safety razors. Thus, when a bead guard having a height of 0.002 inch, for example, is positioned at the juncture of the blade bevel and honed surface it is apparent that the same number of single edge blades, as usual, may be packaged in and dispensed from a conventional injector cartridge. The fact that the area immediately adjacent the blade cutting edge is virtually immune to design changes among the various safety razor manufacturers insures that the blade will be suitable for use with any razor employing the various conventional blade designs, such as a single edge, double edge or injector type to which the invention is applied.

It is obvious that the basic principle, per se, would be applicable if the bead were positioned further away from the cutting edge or even on a parallel surface portion of the blade body if the bead were made quite large. This is, however, impractical for the reasons stated. Thus, in order to assure that the blades may be stacked in face-to-face engagement and dispensed from a conventional dispenser; the presence of the bead should not increase the overall blade thickness. In the case of an injector blade, a single bead need be applied to only one side thereof since there is only one choice of blade orientation in the razor. Four separate beads would, of course, be applied to a double edge razor blade to assure the proper positionment of a bead irrespective of the manner in which the double edge razor blade is oriented in the razor.

Furthermore, the bead should be positioned immediately adjacent the cutting edge to insure that the skin deflection is assumed primarily by the bead rather than the cutting edge and to create a minimal distance between the skin bearing surfaces bridging the cutting edge to assure that the magnitude of the skin roll will be minimal.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an injector type blade showing the preferred bead guard positionment;

FIG. 2 is a cross-sectional view taken through a conventional injector razor showing the blade of FIG. 1 in place and the handle thereof broken away;

FIG. 3 is an enlarged schematic illustration of the manner in which the skin surface is deformed during a shaving operation using a conventional unbeaded blade;

FIG. 4 is an enlarged schematic illustration similar to that of FIG. 3 illustrating the manner in which the skin surface is deformed during a shaving operation using the bead guarded blade of the present invention;

FIG. 5 is a greatly enlarged combined schematic illustration of FIGS. 3 and 4; and

FIG. 6 is a cross-sectional view of a conventional double edge razor incorporating a plurality of bead guards.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention is illustrated in FIG. 1 as comprising an injector blade 10 including the conventional opposed beveled surfaces 12 merging with opposed honed surfaces 14 and terminating in a cutting edge 16. A guard in the form of a bead 18, having an arcuate skin engaging surface, is positioned in closely spaced parallel relation to the cutting edge 16 as by being integrated with the blade along a juncture line between a beveled surface 12 and a honed surface 14. The spacing between bead guard 18 and cutting edge 16 is defined by the tangency of the arcuate skin engaging surface on the bead guard to a plane 42 (FIG. 4) passing substantially through the cutting edge 16. The bead guard position may be more specifically defined as immediately adjacent the cutting edge by imposing a limitation that the acute angle formed between plane 42 and bisector 22 (FIG. 5) of the honed cutting surfaces exceeds that acute angle between bisector 22 and the plane of adjacent honed cutting surface 14. It will be apparent that this angular relationship would not be maintained as the bead guard is moved rearwardly to the parallel blade surfaces 20. In a preferred form of the invention, the bead 18 is a suitable metal wire which is integrated with the blade in any desired manner such as by electron beam or ultrasonic welding. Alternatively, the bead guard could be comprised of a plastic wire or many spaced dots of metal or plastic which would, efiectively, form a virtually continuous bead.

The dimensions of the bead guard 18 are quite small as will be apparent from an inspection of FIG. 2 and does not extend outwardly beyond the confines of those parallel planes defined by the parallel surfaces 20 of blade 10. Typically, the bead height, as measured perpendicular to the bisector 22 of the honed cutting surfaces 14, does not exceed about 0.002 inch. This dimensional consideration is important from the standpoint of adaptability to conventional packaging techniques and particularly wherein the blades are normally stacked in face-to-face engagement.

The manner in which bead guard 18 cooperates with the conventional razor guard or soap bar 24 of a conventional injector razor 26 to decrease the likelihood of nicks and skin abrasions will be apparent from a comparative inspection of FIGS. 3-5. In FIG. 3 is schematically illustrated the manner in which a typical skin surface is deformed during a shaving operation employing a conventional injector razor 26 and a conventional unbeaded injector blade 28. As pressure is applied to the razor and the same is moved along the skin surface 30 with the blade angle at approximately 30 to the undeflected skin surface; the razor guard 24 depresses the skin as at 32 to create a skin roll 34 which follows razor guard 24 in its passage across the skin surface. The skin roll 34 is thus in advance of the blade and is flattened out by engagement with the cutting edge 36 and the under honed surface 38 thereof. Because of the fact that cutting edge 36 engages the skin surface at the base of skin roll 34, the shaving action is, in effect, taking place in the skin valley 40 which defines a large angle of attack with respect to the blade edge 36.

The primary purpose of the invention is to reduce the magnitude of the skin roll 34 under any given shaving condition to thereby decrease the angle of attack made by the blade with respect to the skin surface and to minimize the role of the blade cutting edge as a skin bearing and deflecting surface. This is accomplished by the positionment of the bead guard 18 just rearwardly of the cutting edge 16 as shown in FIG. 4. The bead guard 1d cooperates with razor guard 24 to provide spaced skin bearing surfaces bridging the blade edge 16 to thereby reduce the magnitude of the skin roll as compared with that created under similar shaving conditions with an unbeaded blade This reduction in magnitude of the skin roll decreases the blade angle of attack and at least partially relieves the blade edge from its role as that skin engaging element about which the skin surface must deflect in order to transition from the skin roll to a substantially flat surface.

The effect is produced in a manner analogous to a manual stretching of the skin during a shaving operation. Thus, as will be noted from FIG. 4, a plane 42 joining the lower skin engaging surfaces of the bead guard 18 and razor guard 24 should pass substantially through or just below the cutting edge 16 so that the skin is depressed both fore and aft of the cutting edge. Because of the loose and flexible nature of the skin, that skin area between these spaced skin bearing surfaces does not follow the straight line path of plane 42 joining their lower surfaces but it tends to do so thus substantially reducing the overall magnitude of the skin roll. The comparative result is depicted in FIG. 5 wherein the reduced skin roll is indicated in solid line at 43 as contrasted with the phantom line showing of the skin deflection using an unbeaded blade.

The application of the invention to a double edge razor blade 44 is illustrated in FIG. 6 wherein four distinct bead guards 46 are applied at the four distinct line junctures 48 between the beveled and honed

surfaces

50, 52, respectively. It will be noted that the presence of bead guards 46 do not increase the overall thickness of the blade as defined by the separation of the parallel surfaces 54 comprising the major portion of the blade body.

I claim:

I. In a razor blade having tapered surface means terminating at an angle defining a cutting edge at the apex thereof, the improvement comprising; bead guard means integrated with at least one of said surface means extending in spaced parallel relation to said cutting edge; said bead guard means being substantially coextensive in length with said cutting edge; and said bead guard means including arcuate skin engaging surface means; said spaced relation of said bead guard means relative to said cutting edge being defined by the tangency of said arcuate surface means to a plane passing substantially through said cutting edge; and said plane defining an acute angle with the bisector of said angle which exceeds an acute angle defined between the plane of said surface means and said bisector.

2. In a razor blade having tapered surface means terminating at an angle defining a cutting edge at the apex thereof, the improvement comprising bead guard means integrated with at least one of said surface means extending in spaced parallel relation to said cutting edge; said razor blade including parallel surfaces defining a maximum blade thickness; and said bead guard means lying substantially between parallel planes coplanar with said parallel surfaces.

3. In a razor blade having tapered surface means terminating at an angle defining a cutting edge at the apex thereof, the improvement comprising; bead guard means integrated with at least one of said surface means extending in spaced parallel relation to said cutting edge and positionally defined by intersection with a plane passing through said apex whose angular relationship with the bisector of said angle exceeds the internal angular relationship'of said bisector with one of said surfaces.

4. In combination with a safety razor including a razor guard having a skin engaging surface; a razor blade having bead guard means integrated therewith and extending outwardly from tapered surface means thereon; and the cutting edge of said blade terminating substantially at the plane passing through an outermost porn'on of said bead guard means and an outermost skin engagable surface of said razor guard.

Claims

1. In a razor blade having tapered surface means terminating at an angle defining a cutting edge at the apex thereof, the improvement comprising; bead guard means integrated with at least one of said surface means extending in spaced parallel relation to said cutting edge; said bead guard means being substantially coextensive in length with said cutting edge; and said bead guard means including arcuate skin engaging surface means; said spaced relation of said bead guard means relative to said cutting edge being defined by the tangency of said arcuate surface means to a plane passing substantially through said cutting edge; and said plane defining an acute angle with the bisector of said angle which exceeds an acute angle defined between the plane of said surface means and said bisector.

3. In a razor blade having tapered surface means terminating at an angle defining a cutting edge at the apex thereof, the improvement comprising; bead guard means integrated with at least one of said surface means extending in spaced parallel relation to said cutting edge and positionally defined by intersection with a plane passing through said apex whose angular relationship with the bisector of said angle exceeds the internal angular relationship of said bisector with one of said surfaces.

4. In combination with a safety razor including a razor guard having a skin engaging surface; a razor blade having bead guard means integrated therewith and extending outwardly from tapered surface means thereon; and the cutting edge of said blade terminating substantially at the plane passing through an outermost portion of said bead guard means and an outermost skin engagable surface of said razor guard.