Cartridges Having Tandemly Mounted Cutting Edges On Two Sides Thereof

Abstract

The specific disclosure provides a bonded blade cartridge having two double edge blades separated by a spacer rigidly secured between a cap member and a blade seat member. Transverse center portions of the lower surfaces of the cap member and of the spacer are curved to a greater degree than respective corresponding transverse center portions of the upper surfaces of the spacer and of the blade seat member. The greater degree of curvature of the lower surface of the spacer ensures that the bottom blade cutting edges are in proper abutting engagement with upwardly extending blade stops on the blade seat member. The greater degree of curvature in the lower surface of the cap member ensures that the cutting edges of the top blade are in proper abutting engagement with upwardly extending blade stops formed on the spacer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to safety razors of a type having at least two blades permanently bonded in a disposable cartridge. More particularly, the present invention relates to cartridge structure for tandemly aligning the cutting edges of a plurality of double edge blades.

2. Description of the Prior Art

Disposable cartridges are known in which at least one blade is permanently secured in or between molded plastic material shaped to leave a cutting edge or edges exposed and to form a guard surface in front of the cutting edge or edges. The cartridge is detachably secured to a handle and is discarded when the cutting edges are no longer useful.

U.S. Pat. No. 2,741,839 provides a safety razor in which equally dimensioned double edge blades are flexed to provide tandemly arranged cutting edges at opposite sides of the razor. The tandemly mounted blades of U.S. Pat. No. 2,741,839 are positioned upwardly and rearwardly with respect to guard bar surfaces by locating the blades on centrally located razor pins.

SUMMARY OF THE INVENTION

An advantage of bonded blade cartridges is that it is possible to optimize the shaving angles defined by the relationship between the cutting edges and the guard bar surfaces to minimize the possibility of nicks and cuts and to maximize shaving efficiency.

In accordance with the present invention, there is provided a disposable razor blade cartridge comprising a plurality of double edge blades rigidly secured between an upper member and a blade seat member. A spacer is provided between opposing side surfaces of the blade. The blade seat member and the spacer have upwardly extending blade stop members at the outer four corners thereof. Each blade cutting edge is brought into abutting engagement with a respective set of blade stop members to provide a pre-determined orientation with respect to a guard bar surface. Lower curved surfaces of the upper member and of the spacer have transverse center portions which are curved to a greater extent than opposing transverse center portions of the upper surfaces of the spacer and of the blade seat member to provide transverse gaps in the cartridge. The transverse gaps ensure that the cutting edges of the blades are properly positioned in abutting engagement with the blade stops.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a specific embodiment of the present invention showing a disposable cartridge and a holder therefor;

FIG. 2 is an exploded perspective view of the disposable cartridge shown in FIG. 1;

FIG. 3 is a bottom plan view of a cartridge cap member;

FIG. 4 is a cross-sectional view of the cartridge shown in FIG. 1;

FIG. 5 is an exploded view of a portion of FIG. 4;

FIG. 6 is another cross-sectional view of a cartridge showing another embodiment of the present invention; and

FIG. 7 is an exploded view of a portion of FIG. 6.

DESCRIPTION OF SPECIFIC EMBODIMENTS

FIG. 1 shows in an exploded view a cartridge 10 and a cartridge holder 12. The cartridge 10 has a pair of double edge blades 26, 30 bonded permanently between an upper member or cap 24 and a blade seat member 20. The blades 26, 30 are maintained in a separated state by a spacer 22. The spacer 22 has a plurality of teeth 28 protruding a slight distance in front of the cutting edges of the top blade 26.

The blade seat member 20 has a guard bar 32 postioned on opposite longitudinal ends thereof. The guard bars 32 are spaced from the body portion of the blade seat member 20 by a plurality of ribs 33 to provide flow channels 34 between the guard bars 32 and the blade seat member 20. The flow channels 34 provide a path for shaving residue from the cutting edges of the bottom blade 30 downwardly between the guard bars 32 and the blade seat member 20.

The holder 12 includes a handle 13 to which a frame member 14 is secured. A generally U-shaped channel member 16 and a spring member 17 are secured to the upper portion of the frame member 14. The upper part of the U-shaped channel member 16 has rearwardly and forwardly extending flange portions 15 for sliding engagement in a T-shaped channel 18 transversely formed in the bottom of the blade seat member 20.

With reference to FIG. 2, the cap member 24 has a longitudinally upwardly curved lower surface 68, and a plurality of transversely spaced posts 36 extending downwardly from the lower surface 68 (FIG. 3). The posts 36 extend through a slot 38 in the top blade 26, apertures 44 in the spacer 22, a slot 38' in the bottom blade 30 and apertures 54 in the blade seat member 20. As shown in FIG. 4, the bottom portions of the posts 36 are staked, for example, by ultrasonic, mechanical or heat energy, to deform the lower ends and thereby bond the components of the cartridge 10 together.

Each of the blades 26, 30 has two transverse rows of perforations 40, 42; 40,' 42' formed therethrough. Shaving residue generated between the cutting edges of the blades 26, 30 passes between the teeth 28 formed on the spacer and down through the apertures 56, 58 formed in the blade seat member 20.

Upwardly extending top blade stop members 46, 48, 50, 51 are provided on the outer four corners of the spacer 22 for abutting engagement with the cutting edges of the top blade 26. Similarly, the blade seat member 20 has upwardly extending bottom blade stop members 60, 62, 64, 66 at the outer four corners thereof for abutting engagement with the cutting edges of the bottom blade 30.

An upper surface 45 of the spacer 22 is longitudinally upwardly curved and has a pre-determined radius of curvature. The lower surface 68 of the cap member 24 has a tansverse center portion 68' with a radius of curvature less than the pre-determined radius of curvature of the spacer upper surface 45. Similarly, an upper surface 67 of the blade seat member 20 has a predetermined radius of curvature, and a lower surface 53 of the spacer has a transverse center portion 53,' which portion has a radius of curvature less than that of the blade seat upper surface 67. As shown in FIG. 4, the smaller radius of curvature in the transverse center portions 68', 53' provides transverse gaps 70, 72 between the cap member 24 and the top blade 26 and between the spacer 22 and the bottom blade 30.

The transverse gaps 70, 72 compensate for manufacturing tolerances in the formation of the components of the cartridge 10 which may be in the order of 0.002 - 0.003 inch. The compensation is accomplished by absorbing the tolerances in the gaps 70, 72 after the blade edges are in an abutting engagement with respective pairs of stops 48, 50; 46, 51; 62, 64; 60, 66 on the spacer 22 and the blade seat member 20. In this manner, the relationship between the cutting edges and the guard bar 32 on each side of the cartridge 10 is pre-determined by the relative positions of the blade stops on the spacer 22 and the blade seat member 20.

In the embodiments shown, the length and width dimensions of the blades 26, 30 are identical. The FIG. 4 embodiment provides for the radius of curvature of the spacer upper surface 45 to be less than the radius of curvature of the blade seat upper surface 67. This differnence in radii of curvature narrows the assembled distance between the cutting edges of the top blade 26 to less than the distance between the cutting edges of the bottom blade 30 such that the blades are tandemly mounted in the cartridge 10. As clearly shown in FIG. 5, this configuration situates the cutting edges of the top blade 26 to a cutting angle with respect to the guard bar 32 which is less than the cutting angle of the edges of the bottom blade 30.

The embodiment of FIGS. 6 and 7 is a modification of the embodiment of FIGS. 4 and 5 to equalize the cutting angles of the top and bottom blades. The components of the embodiment of FIGS. 6 and 7 which are identified by primed numerals indicate functional correspondence with components of the embodiment of FIGS. 4 and 5. However, the top blade 26' is reversed curved at 74 and 76 to orientate the outer ends of the top blade 26' parallelly with the outer ends of the bottom blade 30'.

The cap member 24, the spacer 22 and the blade seat member 20 can each be formed of molded plastic, or can be composed of other suitable materials such as metal.

It is also contemplated that the top blade 26 can have an unassembled cutting edge-to-cutting edge distance less than that of the bottom blade 30. In this embodiment, the radii of curvature of the upper surfaces of the spacer 22 and blade seat member 20 are equal to provide equivalent blade edge cutting angles with respect to the guard bars 32.

Claims

What is claimed is:

1. A disposable razor blade cartridge comprising, in combination:

a blade seat member comprising a guard surface on each one of two opposite sides of said seat member, a pair of spaced first blade stop surfaces extending upwardly and rearwardly of opposite ends of each one of the guard surfaces, and an upwardly curved upper surface extending between each of the pairs of first blade stop surfaces,

a first double cutting edge blade located on said blade seat upper surface with each one of the cutting edges thereof abutting a respective one of the pairs of first blade stop surfaces, each one of the first blade cutting edges being spaced upwardly and rearwardly from a respective one of the guard surfaces,

a spacer located on said first blade, said spacer comprising a pair of spaced second blade stop surfaces extending upwardly and rearwardly of each one of the first blade cutting edges, an upwardly curved lower surface having the transverse outer portions thereof in abutting engagement with said first blade and a transverse center portion spaced upwardly from said first blade, and an upwardly curved upper surface extending between each of the pairs of second blade stop surfaces,

a second double cutting edge blade located on said spacer upper surface with each one of the cutting edges thereof abutting a respective one of the pairs of second blade stop surfaces, each one of the second blade cutting edges being spaced upwardly and rearwardly from a respective one of the first blade cutting edges,

an upper member comprising an upwardly curved lower surface having the transverse outer portions thereof in abutting engagement with said second blade and a transverse center portion spaced upwardly from said second blade, and

means for rigidly maintaining said first blade, said spacer and said second blade between said blade seat member and said upper member.

2. The cartridge of claim 1 further comprising means for releasably engaging a handle.

3. The cartridge of claim 1 wherein said first and second blades have identical length and width dimensions.

4. The cartridge of claim 1 wherein said maintaining means comprises a plurality of posts extending downwardly from said upper member, and wherein said second blade, said spacer, said first blade and said blade seat member have apertures for the passage of said posts therethrough, said posts being deformed at the lower ends thereof to prevent removal from said apertures.

5. The cartridge of claim 3 wherein said upper surface of said spacer and said lower surface of said upper member are curved to a greater degree than said upper surface of said blade seat and said lower surface of said spacer to decrease the distance between the cutting edges of said second blade to less than the distance between the cutting edges of said first blade.

6. The cartridge of claim 5 wherein said first blade has a pre-determined cutting angle, and wherein the outer ends of said upper surface of said spacer and said lower surface of said upper member are reversed curved to provide a second blade cutting angle corresponding to said pre-determined cutting angle.

7. The cartridge of claim 1 wherein said upper surface of said blade seat member has a first pre-determined radius of curvature along at least a transverse center portion thereof, and said transverse center portion of said spacer lower surface has a radius of curvature less than said first pre-determined radius of curvature, and wherin said upper surface of said spacer has a second pre-determined radius of curvature along at least a transverse center portion thereof, and said transverse center portion of said lower surface of said upper member has a radius of curvature less than said second pre-determined radius of curvature.

8. The cartridge of claim 7 wherein said first predetermined radius of curvature is greater than said second pre-determined radius of curvature.

9. The cartridge of claim 7 wherin the length of said second blade between the cutting edges thereof is less than the length of said first blade between the cutting edges thereof.

10. The cartridge of claim 9 wherin said first predetermined radius of curvature is equal to said second predetermined radius of curvature.

11. A disposable razor blade cartridge comprising, in combination:

a blade seat member comprising a guard surface on each one of two opposite sides of said seat member, a pair of spaced first blade stop surfaces extending upwardly and rearwardly of opposite ends of each one of the guard surfaces, and an upwardly curved upper surface extending between each of the pairs of first blade stop surfaces,

a first double cutting edge blade located on said blade seat upper surface with each one of the cutting edges thereof abutting a respective one of the pairs of first blade stop surfaces, each one of the first blade cutting edges being spaced upwardly and rearwardly from a respective one of the guard surfaces,

a spacer located on said first blade, said spacer comprising a pair of spaced second blade stop surfaces extending upwardly and rearwardly of each one of the first blade cutting edges, an upwardly curved lower surface having the transverse outer portions thereof in abutting engagement with said first blade and a transverse center portion spaced upwardly from said first blade, and an upwardly curved upper surface extending between each of the pairs of second blade stop surfaces,

a second double cutting edge blade located on said spacer upper surface with each one of the cutting edges thereof abutting a respective one of the pairs of second blade stop surfaces, each one of the second blade cutting edges being spaced upwardly and rearwardly from a respective one of the first blade cutting edges,

an upper member comprising an upwardly curved lower surface having the transverse outer portions thereof in abutting engagement with said second blade and a transverse center portion spaced upwardly from said second blade, and

means interconnecting said blade seat member and said upper member for rigidly maintaining said first blade, said spacer and said second blade between said blade seat member and said upper member,

said upper surface of said blade seat member having a first pre-determined radius of curvature along at least a transverse center portion thereof, and said transverse center portion of said spacer lower surface having a radius of curvature less than said first predetermined radius of curvature, and

said upper surface of said spacer having a second pre-determined radius of curvature along at least a transverse center portion thereof, and said transverse center portion of said lower surface of said upper member having a radius of curvature less than said second pre-determined radius of curvature.