Shaving System

Abstract

A shaving system comprises a leading blade member having a cutting edge and a following blade member having a cutting edge. The cutting edges are supported in spaced parallel relation to one another by structure which extends along substantially the entire lengths of the leading and following blade members and a guard structure is disposed forwardly of the leading cutting edge. The guard structure is disposed relative to the leading cutting edge to define a leading edge tangent angle in the range of 20.degree.-32.degree. and a span (S.sub.L) in the range of 0.030-0.080 inch, the following cutting edge is rearwardly offset from the leading cutting edge to define a span (S.sub.F) in the range of 0.030-0.080 inch, and each cutting edge has an exposure in the range of from -0.002 inch to +0.004 inch.

Description

SUMMARY OF INVENTION

This invention relates to shaving systems and is directed more particularly to a shaving system that includes a plurality of cutting edges.

It is a principal object of this invention to provide a novel and improved shaving system which provides both a close and a safe shave. A further object of the invention is to provide such a system in which a plurality of cutting edges are fixed in position with respect to one another and with respect to a cooperating guard structure to define a desired geometrical relationship between various components of the system.

It has long been desirable in the shaving field to provide a shaving system which provides both a very close shave and a safe shave, i.e., a shave with minimal risk of nicks and cuts. Such a shaving system to be practical must be capable of manufacture by mass production techniques and should be easy to use and effective in a wide range of shaving environments.

It has been discovered that a plural cutting edge shaving system in which certain critical geometrical relationships are observed provides superior shaving characteristics. Such a shaving system includes two cutting edges disposed parallel to one another and in spaced relation to provide leading and following cutting edges so that both cutting edges are successively active with respect to the hair elements being cut during a single shaving stroke. The cutting edges are supported in spaced parallel relation to one another by structure which extends along substantially the entire lengths of the blade members that define those cutting edges. A guard structure is disposed in fixed relation to the cutting edges to define in part the desired geometrical relationship. Significant components of that geometrical relationship include "blade tangent angle," "exposure," and "span." "Blade tangent angle" is defined as the angle between the bisector of the included angle of the cutting edge and a line from the cutting edge tangent to the skin engaging surface immediately forward of that cutting edge. "Exposure" is defined as the distance (measured perpendicularly to a reference plane defined by skin engaging surfaces immediately in front of and behind the cutting edge) from the cutting edge to that plane, the exposure being considered positive when the cutting edge is located on the outer (skin) side of that plane and being considered negative when the cutting edge is further from the skin than that plane. "Span" is defined as the distance between the cutting edge and the skin engaging surface forward of that cutting edge.

In a shaving system in accordance with the invention, the leading cutting edge of the shaving system has a blade tangent angle in the range of 20.degree.-32.degree., an exposure in the range of -0.002 to +0.004 inch and a span in the range of 0.030-0.080 inch, while the following cutting edge has an exposure in the range of -0.002 to +0.004 inch and a span in the range of 0.030-0.080 inch.

In a preferred embodiment the leading cutting edge of the shaving system has a blade tangent angle of 26.degree..+-.1.5.degree., an exposure of 0.0015.+-.0.0015 inch and a span of 0.059.+-.0.004 inch, while the following cutting edge has an exposure of 0.0015.+-.0.0015 inch and a span of 0.062.+-.0.004 inch. The leading and following cutting members are planar blade members and the bodies of the blade members are disposed parallel to one another. Cooperating guard and cap structures are molded of plastic material and the cap, base and spacer members and two blade elements are secured together in fixed geometrical relationship to define a blade unit which is releasably attached to a handle component. The spacer member includes a plurality of forwardly extending spaced fingers. Slots in the blades, in cooperation with the fingers and with slots in the base member, provide flow passages adjacent the shaving zone. The handle has an elongated, slightly tapered grip, the upper end of which is angularly offset and defines an extension portion. A transversely extending blade unit coupling structure is disposed at the outer end of the offset extension portion. The blade unit, when secured to the coupling structure, has its guard surface spaced about 0.6 inch forward of the most closely adjacent surface of the elongated grip portion and the reference line tangent to the guard surface that defines the leading blade tangent angle is disposed at an angle of about 39.degree. to the axis of the elongated grip portion.

The plural edge shaving system of the invention provides excellent shaving characteristics, the resulting shave being both extremely smooth and extremely close. While the involved shaving action is not fully understood, there appears to be a dynamic interaction of the plural cutting edges with the hairs being cut during the shaving operation with resulting comfortable, convenient, safe and efficient shaving in a low blade tangent angle, low exposure geometry. The shaving system provides this improved dynamic interaction while facilitating flow of debris resulting from the shaving operation away from the shaving zone. The preferred blade unit and handle configuration provides a balanced and easy to use precision shaving device capable of economic manufacture on a volume production basis.

Other objects, features and advantages of the invention will be seen as the following description of a particular embodiment progresses, in conjunction with the drawings in which:

FIG. 1 is a side view of a razor assembly incorporating a shaving system in accordance with the invention;

FIG. 2 is a perspective view of the razor assembly shown in FIG. 1;

FIG. 3 is a front view of the razor assembly shown in FIG. 1;

FIG. 4 is an exploded perspective view of components of the blade unit employed in the razor assembly as shown in FIG. 1; and

FIG. 5 is an enlarged view of a portion of the blade unit employed in the embodiment shown in FIG. 1 and illustrates certain geometric relationships .

DESCRIPTION OF PARTICULAR EMBODIMENT

The razor assembly shown in FIGS. 1 and 2 includes a handle component 10 and a blade unit component 12. The handle component has a grip portion 14 molded of high impact polystyrene that is 4 1/4 inches long and of generally square cross-section and that slightly tapers towards its upper end. Grooves 16 along a portion of the length of grip 14 facilitates its handling by the user. A continuation of the grip in the form of neck portion 18 extends forwardly and upwardly from the upper end at an angle of 120.degree. to the axis of grip 14. Secured at its outer end is a plated brass transversely extending coupling structure 20 that has two outwardly directed rail members 22, the upper surfaces of which define a reference plane 24 perpendicular to the axis of neck portion 18. The reference plane 24 is spaced a distance H of 0.55 inch from the junction of neck portion 18 with the rear surface of the grip portion 14. A laterally extending slot 26 is formed in the base of coupling structure 20 on either side of the connection to neck portion 18. Spring plate 28 functions as a resilient latch member and cooperates with the rails 22 of the coupling structure 20 to secure the blade unit 12 on the handle 10.

The cooperating blade unit 12 includes a base or platform member 30 molded of high impact polystyrene that includes integral coupling groove structure 32 in which the rails 22 are received and a transversely extending guard structure 34. On the upper surface of the base platform structure are disposed a steel leading blade element 36 and a steel following blade element 38 which are maintained in spaced relation by aluminum spacer member 40. The blade elements and spacer member are secured to the base member by cap member 42 also molded of high impact polystyrene. The blade elements 36, 38 are disposed parallel to one another in this embodiment and, when the blade unit 12 is attached to handle 10, at an angle of 35.degree. to the reference plane 24 defined by the upper surfaces of the rails 22, and at an angle of 65.degree. to the axis of the handle.

The surface of guard structure 34 extends about 0.23 inch above the reference plane 24 and is offset about 0.6 inch from the front surface of the upper end of the grip portion 14.

A front view of components of the shaving system is shown in FIG. 3.

Additional details of the blade unit 12 may be seen with reference to the exploded view of FIG. 4. The base member 30 includes a planar support surface 50 in which are formed a series of four securing apertures 52 and a series of four drain slots 54. There is an upwardly extending vertical surface 56 at the rear of platform 50 in which are disposed two recesses 58 and a downwardly extending vertical surface 60 at the front of platform 50. A recess 62 is formed at either end of platform 50 and end wall structures 64 extend downwardly and forwardly from either end of platform surface 50. Guard structure 34 extends between the forward extending portions of the end walls 64 and in spaced relation from front wall 60 of base 30. Spaced webs 66, which extend forwardly from wall 60 to the guard member 34, increase the rigidity of that guard member and define drain recesses between surface 60 and the guard. At either end of the guard member is an upwardly projecting vertical reference surface 68. Extending downwardly from the lower end of the base member 30 at the front and rear thereof are projections which include inwardly extending flanges 70 at their outer ends that define with the lower surface of the base two parallel opposed grooves which are adapted to receive the rails 22 of the handle component to secure the blade unit 12 to that handle. Spring plate 28 engages a notch in the forward flange 70 to latch the blade unit against transverse movement.

Each blade element 36, 38 has parallel front and rear edges, the front edge of each blade element being sharpened to define a cutting edge 80. Formed in each blade member are series of four axially extending slots 82 and four irregularly shaped apertures 84. The forward edges 86 of apertures 84 are straight and of the same length as slots 82 while the rear edges 88 of apertures 84 have a curvature corresponding to the curvature of the securing apertures 52 in base member 30.

Spacer 40, interposed between the blade elements, has a length of 1 1/2 inches, a width of 0.24 inch and a thickness of 0.020 inch. Formed in the forward edge of spacer 40 are a series of recesses 98, each of which is 0.080 inch deep and about one-eighth inch long. These recesses define a series of spaced forwardly directed fingers 100, each of which is 0.056 inch in width. Each of the fingers 100 culminates in an 0.020 inch wide tip 102 which terminates the inclined side wall surfaces 104, 106 which extend rearwardly and diverge towards the main body of the spacer member 40 and also are inclined vertically so that the top surface 108 of each finger is smaller than the corresponding bottom surface of that finger. The spacer is further provided with holes 110 that are alignable with the holes 52 at the base member and the holes 84 in the blade elements. Recesses 112 in the rear edge of spacer 40 are alignable with the recesses 58 in the base member.

Cap member 42 molded of high impact polystyrene includes a transversely extending portion 118 disposed between end wall portions 120, 122. Pins 124 extend downwardly from the transversely extending portion 118 and are alignable with the holes 52, 84 and 110 in the base, blades and spacer members, respectively. The pins are hollow at their free ends to facilitate cold heading. The top surface 126 of portion 118 is inclined at an angle of 73.degree. to the axis of pins 124 and the top surfaces of end walls 120, 122 project above surface 126 and are inclined at an angle of 70.degree. to the axes of pins 124. The end walls 120, 122 also extend beyond the forward edge of the cap surface 126 and each includes an exterior vertical reference surface 130 that is adapted to engage the reference surface 68 on base member 30 and interior vertical reference surfaces 134 and 136 which are used for locating the blade members 36, 38 relative to one another and to the guard structure 34 in the assembled blade unit. An elongated recess 138 defined by transverse portion 118 and the end wall portions 120, 120 receives the wall surface 56 of the base member 30.

In assembly, the base 30, blade elements 36, 38, spacer 40 and cap member 42 are disposed in aligned relation with pins 124 extending through the corresponding holes 52, 84 and 110. The components are loosely held in stacked relation under light pressure and suitable means such as a jet of air or a mechanical tool applies force through the openings defined by recesses 58 and cooperating portions of cap 42 to urge the two blade members 36, 38 forwardly against stop surfaces 134, 136, respectively. The assembly is then clamped firmly together and the free ends of the pins 124 are expanded in a cold heading operation to secure the components of the blade unit firmly together.

In the assembled blade unit, as indicated in FIG. 5, the cutting edge 80 of the leading blade 36 extends over the recesses between forward wall 60 and the guard member 34, while the cutting edge 80 of the following blade 38 is located above the recesses 98 between fingers 100 of spacer 40 so that paths are provided for communication through the slots 82 and the forward ends of apertures 84 in the leading blade 36 and the slots 54 in the base member 30. These passages facilitate the flow away from the shaving zone of lather and debris resulting from the shaving operation.

Features of the resulting geometry in this blade unit are also illustrated in FIG. 5. With reference to that figure, a first reference line 150 extends from the cutting edge 80.sub.F of following blade 38 to skin engaging point 152 on guard 34 and the perpendicular distance E.sub.L that the cutting edge 80.sub.L of the leading blade 36 projects beyond that line is the "exposure" of that blade. A similar reference line 154 extends from the cutting edge 80.sub.L of the leading blade 36 to skin engaging point 156 on surface 126 of cap 42 and the perpendicular distance E.sub.F that the cutting edge 80.sub.F of the following blade 38 projects beyond from that line is the "exposure" of the following blade. Another relationship useful in defining shaving geometry is "blade tangent angle," which for leading blade 36 is the angle between line 158 (a reference line which bisects the included angle of the cutting edge 80.sub.L of the leading blade 36) and the line 160 that extends from cutting edge 80.sub.L of blade 36 to a skin engaging point on guard member 34 (the latter point being slightly offset from point 152). A further relationship of interest is "span," the distance between the cutting edge and the nearest skin engaging point forward of that edge. Span for the leading cutting edge 80.sub.L is denominated S.sub.L and is the distance between edge 80.sub.L and a skin engaging point on guard 34 while the span S.sub.F, for the trailing blade 38 is the distance between its sharpened edge and the sharpened edge of the leading blade 36.

The blade unit in the illustrated embodiment has a blade tangent angle A.sub.L for leading blade 36 of 26.degree., a blade tangent angle A.sub.F for following blade 38 of 22.degree.50'; exposures E.sub.L and E.sub.F each of 0.0015 inch; S.sub.L of 0.059 inch; and S.sub.F of about 0.062 inch.

It will be understood that the system may take many forms other than that of the particular above-described embodiment. For example, in alternative constructions more than two blades may be provided. Also, the plane of one or more of the following blades may be set at a different angle than the leading blade. The blade unit geometry may be used with various handle configurations. While there are advantages to the replaceable blade unit feature, it will be apparent that the shaving system may be incorporated in a device in which the handle is integral with the blade unit.

Therefore while a particular embodiment of the invention has been shown and described, it is to be understood that these and various other modifications thereof will be apparent to those skilled in the art and therefore it is not intended that the invention be limited to the disclosed embodiment or to details thereof and departures may be made therefrom within the spirit and scope of the invention as defined in the claims.

Claims

What is claimed is:

1. A shaving system comprising a leading blade member having a planar body and a cutting edge, a following blade member having a planar body and a cutting edge, said blade members being permanently secured together in fixed geometrical relationship, a guard structure disposed forwardly of the cutting edge of said leading blade member, and blade member support structure including a cap member disposed rearwardly of said following cutting edge and a base member having a front wall surface, said guard structure extending parallel to said front wall surface but spaced therefrom to form a slot therebetween, said cap and base members engaging the bodies of said leading and following blade members and including means along substantially the entire length of said leading and following blade members for rigidly supporting said cutting edges in spaced, parallel relation to one another,

said guard structure being disposed relative to said leading cutting edge to define a leading edge tangent angle in the range of 20.degree.-32.degree. and a span (S.sub.L) in the range of 0.03-0.08 inch,

said following cutting edge being rearwardly offset from said leading cutting edge to define a span (S.sub.F) in the range of 0.03-0.08 inch, and

each cutting edge having an exposure of 0.0015 .+-.0.0015 inch.

2. The system as claimed in claim 1 wherein the tangent angle of said following edge is less than said leading edge tangent angle.