CA-3177495-C - SHAVING DEVICE

CA3177495CCA 3177495 CCA3177495 CCA 3177495CCA-3177495-C

Abstract

The present invention relates to a shaving device for shaving a skin surface comprising a housing with a skin contacting surface and at least one cutting blade mounted in the housing, wherein the at least one cutting blade has an asymmetric cross-sectional shape with a first face, a second face opposed to the first face as well as a cutting edge at the intersection of the first face and the second face.

Inventors

Peter Gluche
Ralph Gretzschel
Michael Mertens
Matthias Gester

Assignees

THE GILLETTE COMPANY LLC

Dates

Publication Date: 20260505
Application Date: 20210408
Priority Date: 20200416

Claims (5)

24 CLAIMS 1. A shaving device for shaving a skin surface comprising • a housing with a skin contacting surface and 5 • at least one cutting blade mounted in the housing, wherein the at least one cutting blade has an asymmetric cross-sectional shape with a first face, a second face opposed to the first face as well as a cutting edge at the intersection of the first face and the second face, wherein 10 • the first face comprises a first surface and • the second face comprises a primary bevel having a straight or convex cross-sectional shape and a secondary bevel having a straight or concave cross-sectional shape with 15 • the primary bevel extending from the cutting edge to the secondary bevel, wherein a first intersecting line connects the straight or convex primary bevel with the straight or concave secondary bevel, • the primary bevel has a length d1 being the dimen20 sion projected onto the first surface taken from the cutting edge to the first intersecting line, the length d1 ranges from 0.1 to 7 µm, • the primary bevel and the secondary bevel together have a length d2 being the dimension projected 25 onto the first surface taken from the cutting edge to a distal end of the secondary bevel, the length d2 ranges from 1 to 100 µm, • a first wedge angle 1 between the first surface and the primary bevel or between the first surface and 30 the tangent of the primary bevel through the cutting edge, • a second wedge angle 2 between the first surface and the secondary bevel or between the first surface and the tangent of the secondary bevel through the first intersecting line, and 5 wherein the at least one cutting blade is mounted in the housing that • a clearance angle α between the skin contacting surface and a clearance face which is the primary bevel or the first surface is ≤ 11°, • an effective cutting angle ε between the skin contacting surface and a bisecting line of the first wedge angle 1 is ≥ 10° and 10 • 1 > 2.
2. The shaving device of claim 1, wherein the clearance angel α is ≤ 5°.
3. The shaving device of claim 1, wherein the clearance angel α is ≤ 1°.
4. The shaving device of claim 1, wherein the clearance angel α is ≤ 0°. 5. The shaving device of claim 1, wherein the clearance angel α is from 15 -1° to -5°. 6. The shaving device of any one of claims 1 to 5, wherein the effective cutting angle first wedge angle ε is ≥ 15°. 7. The shaving device of any one of claims 1 to 5, wherein the effective cutting angle first wedge angle ε is ≥ 20°. 20 8. The shaving device of any one of claims 1 to 7, wherein 1 ranges from 5° to 75°. 9. The shaving device of any one of claims 1 to 7, wherein 1 ranges from 10° to 60°. 10. The shaving device of any one of claims 1 to 7, wherein 1 ranges from 25 20° to 45°. 11. The shaving device of any one of claims 1 to 10, the second wedge angle 2 ranges from - 5° to 60°. 26 12. The shaving device of any one of claims 1 to 10, wherein the second wedge angle 2 ranges from 0° to 45°. 13. The shaving device of any one of claims 1 to 10, wherein the second wedge angle 2 ranges 5° to 25°. 5 14. The shaving device of any one of claims 8 to 13, wherein the length d1 is from 0.5 to 5 µm. 15. The shaving device of claim 14, wherein the length d1 is from 1 to 3 µm. 16. The shaving device of any one of claims 8 to 15, wherein the length d2 10 ranges from 5 to 100 µm. 17. The shaving device of claim 16, wherein the length d2 ranges from 10 to 75 µm. 18. The shaving device of claim 16, wherein the length d2 ranges from 15 to 50 µm. 15 19. The shaving device of any one of claims 16 to 18, characterized in that the second face further comprises a straight or concave tertiary bevel with • a second intersecting line connecting the straight or concave secondary bevel with the straight or concave tertiary bevel, 20 • the tertiary bevel extending from the second intersecting line rearward, • a third wedge angle 3 between the first surface and the tertiary bevel or its tangent through the second intersecting line. 25 20. The shaving device of claim 19, wherein the third wedge angle 3 ranges from 1° to 60°. 21. The shaving device of claim 19, wherein the third wedge angle 3 ranges from 10° to 55°. 22. The shaving device of claim 19, wherein the third wedge angle 3 ranges from 30° to 46°. 27 23. The shaving device of claim 19, wherein the third wedge angle 3 is 45°. 24. The shaving device of any one of claims 1 to 23, 5 characterized in that the cutting blade comprises or consists of a blade body consisting of a first material. 25. The shaving device of any one of claims 1 to 23, characterized in that the cutting blade comprises or consists of a blade body comprising or consisting of a first material and a second material 10 joined with the first material. 26. The shaving device of claim 24 or 25, characterized in that the first material comprises or consists of a material selected from the group consisting of • metals, 15 • ceramics comprising at least one element selected from the group consisting of carbon, nitrogen, boron, oxygen and combinations thereof, • glass ceramics, • composite materials made from ceramic materials in a metallic 20 matrix, • hard metals, • silicon or germanium, • single crystalline materials, • glass or sapphire, 25 • polycrystalline or amorphous silicon or germanium, • mono- or polycrystalline diamond, diamond like carbon (DLC), adamantine carbon and • combinations thereof. 28 27. The shaving device of claim 26, wherein the metal is at least one of titanium, nickel, chromium, niobium, tungsten, tantalum, molybdenum, vanadium, platinum, germanium, iron, and alloys thereof. 28. The shaving device of claim 26, wherein the metal is steel. 29. The shaving device of any one of claims 26 to 28, wherein the ceramics comprise at least one of silicon carbide, zirconium oxide, aluminum oxide, sili10 con nitride, boron nitride, tantalum nitride, TiAlN, TiCN, and TiB2. 30. The shaving device of any one of claims 26 to 29, wherein the glass ceramics are aluminum-containing glass-ceramics. 31. The shaving device of any one of claims 26 to 30, wherein the hard 15 metals are sintered carbide hard metals. 32. The shaving device of claim 31, wherein the hard metals are tungsten carbide or titanium carbide bonded with cobalt or nickel. 33. The shaving device of any one of claim 26 to 32, wherein a crystalline plane of the silicon or the germanium is parallel to the second face. 20 34. The shaving device of any one of claims 26 to 33, wherein a wafer orientation of the silicon or the germanium is <100>, <110>, <111> or <211>. 35. The shaving device of claim 25, characterized in that the second material comprises or consists of a 25 material selected from the group consisting of • oxides, nitrides, carbides, and borides, • boron aluminum magnesium • carbon, and • combinations thereof. 29 36. The shaving device of claim 35, wherein the oxides, nitrides, carbides, borides, are at least one of aluminum nitride, chromium nitride, titanium nitride, titanium carbon nitride, titanium aluminum nitride, cubic boron nitride. 5 37. The shaving device of claim 35 or 36, wherein the carbon is at least one of diamond, poly-crystalline diamond, nano-crystalline diamond, and diamond like carbon (DLC). 38. The shaving device of any one of claims 25 and 35 to 37, characterized in that the second material fulfills at least one of the fol10 lowing properties: • a thickness of 0.15 to 20 µm, • a modulus of elasticity of less than 1200 GPa, • a transverse rupture stress σ0 of at least 1 GPa, • a hardness of at least 20 GPa. 15 39. The shaving device of claim 38, wherein the thickness is 2 to 15 µm. 40. The shaving device of claim 38, wherein the thickness is 3 to 12 µm. 41. The shaving device of any one of claims 38 to 40, wherein the modulus of elasticity is less than 900 GPa. 42. The shaving device of any one of claims 38 to 40, wherein the modulus 20 of elasticity is less than 750 GPa. 43. The shaving device of any one of claims 38 to 40, wherein the modulus of elasticity is less than 500 GPa. 44. The shaving device of any one of claims 38 to 43, wherein the transverse rupture stress σ0 is at least 2.
5 GPa. 25 45. The shaving device of any one of claims 38 to 43, wherein the transverse rupture stress σ0 is at least 5 GPa. 46. The shaving device of any one of claims 25 and 35 to 45, characterized in that the second material comprises or consists of nano-crystalline diamond and fulfills at least one of the following properties: 5 • an average surface roughness RRMS of less than 100 nm, • an average grain size d50 of the nano-crystalline diamond of 1 to 100 nm. 47. The shaving device of claim 46, wherein the average surface roughness RRMS is less 50 nm. 10 48. The shaving device of claim 46, wherein the average surface roughness RRMS is less 20 nm. 49. The shaving device of any one of claims 46 to 48, wherein the average grain size d50 of the nano-crystalline diamond is from 5 to 90 nm. 50. The shaving device of any one of claims 46 to 48, wherein the average 15 grain size d50 of the nano-crystalline diamond is from 7 to 30 nm. 51. The shaving device of any one of claims 46 to 48, wherein the average grain size d50 of the nano-crystalline diamond is from 10 to 20 nm. 52. The shaving device of any one of claims 25 and 35 to 51, characterized in that the first material and/or the second material are 20 coated at least in regions with a low-friction material. 53. The shaving device of claim 52, wherein the low-friction material is selected from the group consisting of fluoropolymer materials, parylene, polyvinylpyrrolidone, polyethylene, polypropylene, polymethyl methacrylate, graphite, diamond-like carbon (DLC) and combinations 25 thereof. 54. The shaving device of any one of claims 25 and 35 to 53, characterized in that the first intersecting line is shaped within the second material. 31 55. The shaving device of any one of claims 1 to 54, characterized in that the cutting edge has a tip radius of less than 200 nm. 56. The shaving device of claim 55, wherein the tip radius is less than 100 5 nm. 57. The shaving device of claim 55, wherein the tip radius is less than 50 nm.

Description

1 Shaving device The present invention relates to a shaving device for shaving a skin surface comprising a housing with a skin contacting surface and at least one cutting blade mounted in the housing, wherein the at least one cutting blade has an asymmetric cross-sectional shape with a first face, a second face opposed to the first face as well as a cutting edge at the intersection of the first face and the second face. The following definitions are used in the present application: • the rake face is the surface of a cutting blade over which the cut hair slides that is removed in the cutting process • the clearance face is the surface of a cutting tool that passes over the skin; the angle between the clearance face and the contacting surface to the skin is the clearance angle a • The cutting bevel of a cutting blade is enclosed by the rake face and the clearance face and denoted by the bevel angle 8 2 • The cutting edge is the line of intersection of the rake face and the clearance face In the prior art, the arrangement of the blades within a shaving device has been focused on multi-blade razors. US 3,863,340 teaches a plural edge razor with a lead blade member and a following blade member, wherein the members have unsymmetrical edges hereon and have passages therethrough to facilitate removal of shaving debris from the cutting edge. US 6,655,030 describes a shaving head with at least a first and second cutting member arranged behind and spaced apart from the first cutting member wherein the cutting angle between the skin contacting surface and the second cutting member is equal or higher than the cutting angle between the skin contacting surface of the first cutting member. US 3,842,499 refers to a razor blade assembly with one or more groups of multiple cutting elements wherein the group of cutting elements comprises at least two blades with one blade being chisel shaped. This allows a favorable geometry for tandem blade shaving operations. The dimensions of shaving blade edge profiles and their arrangement in a shaving device are interdependent and are typically optimized to cut hair efficiently. This comprises the following 3 parameters: 1. a small tip radius of the cutting edge for ease of penetration, 2. a small wedge angle 8 of the cutting blade for low cutting force and 3. a large effective cutting angle E of the blade within the shaving device, i.e. its housing, to avoid the hair rotating or sliding away before it is cut and resulting in efficient hair removal. These definitions and parameters are illustrated in the figures of the present application. The first two parameters result in a comfortable shave without tugging on the 3 hairs while they are cut. However, the small tip radius of the edge together with a large blade mounting angle, i.e. the clearance angle a, creates a significant pressure onto the skin surface, which is uncomfortable and may even lead to skin being cut. Reducing the effective cutting angle E improves the safety during shaving. However, in this case conventional symmetric wedge-shaped blades tend to ride over the hair without penetrating and cutting through. During shaving the rake face interacts with the hair and is primarily responsible for the hair cutting performance while the clearance face interacts with the skin and is primarily responsible for the safety of the skin. For optimizing the performance of shaving, it is required to increase the safety of a shaving blade by mounting the blade at a small blade mounting angle, i.e. the clearance angle a, so that the skin facing side of the cutting blade ( clearance face) lies flat on the skin (low clearance angle) and then modify the blade edge profile so that the cutting efficiency of hairs is not compromised by this small clearance angle a. This means the clearance angle a should be as small as possible to ensure skin safety and the effective cutting angle E should be as large as possible to efficiently cut through the hair. Hence the clearance angle a plays the role of the safety angle and the effective cutting angle E plays the role of the efficiency angle. The clearance angle a and the effective cutting angle E are related by E =a+ 8/2 Hence, minimizing the clearance angle a while maintaining an effective cutting angle E of around 22° as has been used in shaving devices successfully for a long time, requires an increase of the cutting bevel angle 8. However, the force to cut through a hair is determined by the thickness of the cutting blade near to the cutting edge and this thickness increases when the bevel angle 8 of the cutting bevel is increased. Hence, increasing the bevel angle 8 to maintain the cutting angle E while reducing the clearance angle a creates a new problem of increasing cutting force and decreasing the shaving comfort due to tugging on the hair, and hence the bevel angle 8 plays the role of the comfort angle. ) . first face a second face as well as a cutting edge at the intersection of the first face