US3863340A

US3863340A - Plural edge shaving system

Info

Publication number: US3863340A
Application number: US287513A
Authority: US
Inventors: Roger L Perry
Original assignee: Gillette Co LLC
Current assignee: Gillette Co LLC
Priority date: 1972-09-08
Filing date: 1972-09-08
Publication date: 1975-02-04
Anticipated expiration: 1992-02-04
Also published as: BR7306936D0; CA1003628A; BE804415A; ZA735905B

Abstract

A plural edge structure for use in shaving includes leading and following members, each of which has two flat faces and a straight sharpened cutting edge parallel to the faces. The two members are permanently secured together with their second faces contiguous, and with their cutting edges parallel to one another and in a plane inclined to the second faces.

Description

United States Patent 1191 Perry 1 Feb. 4, 1975 PLURAL EDGE SHAVING SYSTEM [75] Inventor: Roger L. Perry, Lynnfield Center,

Mass.

[73] Assignee: The Gillette Company, Boston,

Mass.

[22] Filed: Sept. 8, 1972 211 Appl. No.: 287,513

[52] U.S. Cl. 30/346.58, 30/50 [51] Int. Cl B26b 21/54, B26b 21/22 [58] Field of Search 30/32, 50, 346.5, 346.55,

[56] References Cited UNITED STATES PATENTS 2,151,265 3/1939 Clausen 30/34658 X 2,319,980 5/1943 Des Jardins 30/50 X 2,715,267 8/1955 Force 30/50 3,262,206 7/1966 Tomek 30/34659 3,514,856 6/1970 Camp 30/346.55 X 3,786,563 1/1974 Dorion 30/50 FORElGN PATENTS OR APPLICATIONS 478,290 2/1953 Italy 30/346,57 739,501 1/1933 France 30/34655 1,039,546 5/1953 France 30/50 973,077 9/1950 France 30/50 Primary ExaminerAl Lawrence Smith Assistant Examiner-Gary L. Smith [57] ABSTRACT A plural edge structure for use in shaving includes leading and following members, each of which has two flat faces and a straight sharpened cutting edge parallel to the faces. The two members are permanently secured together with their second faces contiguous, and with their cutting edges parallel to one another and in a plane inclined to the second faces.

9 Claims, 4 Drawing Figures I PLURAL EDGE SI'IAVING SYSTEM BACKGROUND OF THE INVENTION This invention relates to shaving and more particularly to plural edge razors used in shaving.

It is known that a plural cutting edge shaving system can provide superior shaving characteristics. Such a shaving system includes at least two cutting edges disposed parallel to one another in spaced relation to provide leading and following cutting edges so that both cutting edges are in contact with the face and are successively active with respect to the hair elements being cut during a single shaving stroke.

The relationships of the parts of a shaving structure are conveniently discussed in terms of certain parameters defined as follows. The blade tangent angle of an edge is the angle between the plane bisecting the two planes defining the edge and the plane through the edge and tangent to the skin engaging surface next forward of the edge. The portion of the bisecting plane external to the material of the edge and the portion of the tangent plane forward of the edge are conventionally used in defining the angle so that a blade tangent angle less than 90 is obtained in any practical shaving geometry. The span of an edge is the distance from the edge to the next forward skin engaging surface measured in the plane through the edge and tangent to the next forward skin engaging surface. The exposure of an edge is the distance of the edge from a plane tangent to both the next forward and the next rearward skin engaging surfaces. The exposure may be positive or negative and is reckoned positive when the edge lies on the skinward side of the doubly tangent plane.

In a plural edge shaving structure having, for example, two edges, the leading edge will be itself the skin engaging surface next forward of the following edge, so that its position will in part determine the blade tangent angle and the exposure of the following edge. Further, the following edge will itself be the next rearward skin engaging surface of the leading edge, so that its position will in part determine the exposure of the leading edge.

It will therefore be readily appreciated that the several geometric parameters discussed above are interrelated, and in devising a plural edge shaving structure it is necessary to consider the interrelationship in order to advantageously combine the optimum values of the several parameters.

It has been found advantageous in a shaving structure to establish a blade tangent angle in the range to 32. With a blade tangent angle less than 20 the edge slides over the face slicing only a portion of the beard hair, while an angle greater than 32 produces a harsh, uncomfortable shave. It has also been found that in a plural edge shaving structure it is advantageous for producing a clean confortable shave to establish for a following edge a span in the range of 0.03 inch to 0.08 inch. It has further been found that cleanest and most comfortable shaving is obtained when the exposure of each cutting edge is in a range of 0.002 inch to +0004 inch.

SUMMARY OF THE INVENTION Objects of the present invention include establishing and permanently maintaining advantageous geometric relationships between the edges of a plural edge shaving structure. reducing the cost of such a structure, and providing such a structure that is easily handled and dispensed using conventional shaving equipment. The invention features a plural edge structure including a leading blade member and a following blade member, each member having the form of a plate bounded by first and second flat faces, and each member having a straight, sharpened cutting edge thereon parallel to the faces. The two members are permanently affixed with their cutting edges positioned parallel to each other and in a plane inclined to the second faces. A particular embodiment features two members which have unsymmetrical edges thereon and have passages therethrough to facilitate removal of shaving debris from the cutting edge and are permanently affixed to each other as by spot welding to maintain the distance between the edges at a value in the range 0.03 inch to 0.08 inch and the blade tangent angle of the following edge at a value in the range 20 to 32. Other objects, features and advantages will appear from the description below of a particular embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I shows a shaving system including a blade holder and a blade dispenser and employing a plural blade structure according to the invention;

FIG. 2 shows in plan view the blade structure used in the shaving system of FIG. 1;

FIG. 3 shows a cross sectional view of the structure shown in FIG. 2, the cross section being taken along the line 3-3 of FIG. 2; and

FIG. 4 shows in cross section a portion of the shaving system to reveal details in the vicinity of the cutting edges, the cross section being taken along the line 4-4 shown in FIG. 1.

DESCRIPTION OF A PARTICULAR EMBODIMENT Shaving system 10, shown in FIG. 1, includes blade holder 12 and blade dispenser M. A plural edge structure I6 according to the invention is conveniently supported in holder 12 for shaving. Replacement blade structures are stored in and dispensed from holder l4 in a manner well understood by most men as well as those specially skilled in the art of shaving equipment. As shown particularly in FIGS. 2 and 3, blade structure 16 is made up of two

identical members

18 and 20. Member 18 has the general form of a thin plate several times longer than it is wide, bounded by flat

parallel faces

22, 24. (In a particular embodiment dimensions are L495 inch X 0.288 inch 0.006 inch.) A sharp cutting edge 26 is formed along one of the longer sides of member 18. Edge 26 is unsymmetrically formed with respect to a median plane through the plate so that it is parallel to faces 22 and 24 but closer to face 24 than to face 22. In the particular embodiment, edge 26 is 0.00l inch from face 24 and 0.005 inch from face 22. As shown particularly in FIG. 4, planes defining edge 26 are oriented at different angles to face 24 so that the bisector plane 42 bisecting edge 26 is inclined to face 24 at an angle of 4", the sense of the angle being such that the bisector 42 diverges from face 24 in the skinward direction. A number of debris removal slots 28 pierce blade member 18 as does elongated slot 30 used to facilitate holding of the structure in holder 12. Blade member 20, with

faces

32 and 34 and edge 36, is identical in all respects with blade member 18, and in particular, edge 36 is parallel to

faces

32 and 34 while lying closer to face 34, and bisector plane 44 associated with edge 36 is inclined to face 32.

Members

18 and 20 are permanently affixed to each other by spot welds 38, to form plural edge structure 16, the position of the members relative to each other being staggered and such that faces 22 and 32 are contiguous and

edges

26 and 36 are permanently maintained parallel to each other at a distance of 0.03l inches and in plane 40 inclined at an angle of l9 to contiguous

flat faces

22 and 32. Member 18, with its edge 26, thus becomes the leading member in structure 16 while member 20, with its edge 36, becomes the following member. The angle between bisector plane 44 of edge 36 and plane 40, containing both edges, is the blade tangent angle of the following edge and in the described structure has the value 23. As shown particularly in H6. 4, blade structure 16 is held in holder 12 with the two

edges

26 and 36 intermediate between forward face guard element 50 and cap element 52. The span S1 of leading edge 26 is established by the position of structure 16 in holder 12. The span S2 of trailing edge 36 is established by blade structure 16 without reference to the holder, the value being 0.031 inch.

It may be noted that by forming the cutting edges unsymmetrically with respect to the median plane of each blade member a lesser total thickness of metal is required for a given edge separation than if the edges were formed on the median plane. This results in an economy of metal use and also facillitates fitting the plural edge structure compactly into holders originally designed for holding single edge structures. The inclination of the bisector angle of the edges to the plane of the blade member facillitates positioning the blade members so that both edges can have both an advantageous exposure and an advantageous blade tangent angle. The permanent affixing of the blade members is advantageous in that it simplifies handling and dispensing of the shaving structure and ensures that the desired relationship between the edges is not impared. ln manufacturing, the blade members are advantageously stamped and sharpened before being joined together. The use of identical members may be advantageous in simplifying manufacturing operations.

While a particular embodiment has been shown and described, it will be understood that various modifications can be made without departing from the spirit and scope of the invention. For example blade members of other or different thicknesses may be used; the blade members may be secured together in a variety of ways including the use of suitable bonding agents to maintain the established geometry; and/or the blade edge may be sharpened to other or different configurations. Therefore, it is not intended that the invention be limited to the disclosed embodiment or to details thereof but departures may be made therefrom within the spirit scope of the invention.

What is claimed is:

l. A plural edge structure for use in shaving, including a leading member and a following member, each of said members having the form of a plate bounded by first and second flat faces, and each said member having two intersecting facets that define a straight, sharpened cutting edge thereon parallel to said faces, each said cutting edge being offset outwardly from the center of the member at least about one-third the distance from the center of the member to its said first face so that it is positioned closer to the first than to the second of said faces, each of said facets being inclined with respect to the immediately adjacent face of the blade member and said two facets defining a bisector plane, said leading and following members being permanently affixed together with their respective second faces con tiguous and with said cutting edges fixed in position parallel to each other in a plane inclined to said second faces in position to maintain a fixed distance perpendicular to said second faces of less than 0.02 inch between said cutting edge of said leading member and said cutting edge of said following member, a span between said cutting edge of said leading member and said cutting edge of said following member in the range of 0.03 inch to 0.08 inch and the angle between the bisector plane of the cutting edge of said following member and said plane containing both edges at a fixed value in the range of 20-32.

2. A structure as claimed in claim 1, said members being spot welded together.

3. A structure as claimed in claim 1, at least said lead ing member having passages vicinity of said cutting edges.

4. A structure as claimed in claim 1, at least one of said members having an edge with a bisecting plane inclined to the second face of the associated member and with said members being affixed with the bisecting planes of said edges inclined to one another and diverging from one another in the direction away from the bodies of said members.

5. A structure as claimed in claim 1 wherein said members are identical to one another.

6. A plural edge razor blade structure for use with a conventional razor having cap and guard structure, and blade structure being insertable into said razor between said cap and guard structure and including a leading rigid blade member and a following rigid blade member, said blade members being identical to one another and each of said members having the form of a plate bounded by first and second flat parallel faces, and each member having two intersecting facets that define a straight, sharpened cutting edge thereon parallel to said faces, each said cutting edge being offset outwardly from the member at least about one-third the distance from the center of the member to its said first face so that it is positioned closer to the first than to the second of said faces, each of said facets being inclined with respect to the immediately adjacent face of the blade member and said two facets defining a bisector plane, said leadingand following members being permanently affixed together with their respective second faces contiguous and with said cutting edges fixed in position parallel to each other in a plane inclined to said second faces in position to maintain a fixed distance perpendicular to said second faces of less than 0.02 inch between said cutting edge of said leading member and said cutting edge of said following member, a span between said cutting edge of said leading member and said cutting edge of said following member in the range of 0.03 inch to 0.08 inch and the angle between the bisector plane of the cutting edge of said following member and said plane containing both edges at a fixed value in the range of 2032.

7. A structure as claimed in claim 6, each of said members having an edge with a bisecting plane inclined to the second face of the associated member and said members being affixed to one another with the bisecting planes of said edges inclined to one another and diverging from one another in the direction away from the bodies of said members.

8. A structure as claimed in claim 7, said members being spot welded together.

9. A structure as claimed in claim 8, each of said members having passages penetrating therethrough for removal of shaving debris from the vicinity of the cutting edge.

0 I i U l

Claims

1. A plural edge structure for use in shaving, including a leading member and a following member, each of said members having the form of a plate bounded by first and second flat faces, and each said member having two intersecting facets that define a straight, sharpened cutting edge thereon parallel to said faces, each said cutting edge being offset outwardly from the center of the member at least about one-third the distance from the center of the member to its said first face so that it is positioned closer to the first than to the second of said faces, each of said facets being inclined with respect to the immediately adjacent face of the blade member and said two facets defining a bisector plane, said leading and following members being permanently affixed together with their respective second faces contiguous and with said cutting edges fixed in position parallel to each other in a plane inclined to said second faces in position to maintain a fixed distance perpendicular to said second faces of less than 0.02 inch between said cutting edge of said leading member and said cutting edge of said following member, a spAn between said cutting edge of said leading member and said cutting edge of said following member in the range of 0.03 inch to 0.08 inch and the angle between the bisector plane of the cutting edge of said following member and said plane containing both edges at a fixed value in the range of 20*-32*.

2. A structure as claimed in claim 1, said members being spot welded together.

3. A structure as claimed in claim 1, at least said leading member having passages vicinity of said cutting edges.

6. A plural edge razor blade structure for use with a conventional razor having cap and guard structure, and blade structure being insertable into said razor between said cap and guard structure and including a leading rigid blade member and a following rigid blade member, said blade members being identical to one another and each of said members having the form of a plate bounded by first and second flat parallel faces, and each member having two intersecting facets that define a straight, sharpened cutting edge thereon parallel to said faces, each said cutting edge being offset outwardly from the member at least about one-third the distance from the center of the member to its said first face so that it is positioned closer to the first than to the second of said faces, each of said facets being inclined with respect to the immediately adjacent face of the blade member and said two facets defining a bisector plane, said leading and following members being permanently affixed together with their respective second faces contiguous and with said cutting edges fixed in position parallel to each other in a plane inclined to said second faces in position to maintain a fixed distance perpendicular to said second faces of less than 0.02 inch between said cutting edge of said leading member and said cutting edge of said following member, a span between said cutting edge of said leading member and said cutting edge of said following member in the range of 0.03 inch to 0.08 inch and the angle between the bisector plane of the cutting edge of said following member and said plane containing both edges at a fixed value in the range of 20*-32*.

8. A structure as claimed in claim 7, said members being spot welded together.