CA-3177496-C - CUTTING BLADE AND HAIR REMOVAL DEVICE

CA3177496CCA 3177496 CCA3177496 CCA 3177496CCA-3177496-C

Abstract

The present invention relates to a cutting blade (I) having a first face (2), a second face (3) opposed to the first face and different from the first face as well as a cutting edge (4) at the intersection of the first face and the second face. The first face comprises a first surface (9) and a primary bevel (7) with a first wedge angle (θ1) between the first surface and the primary bevel. The second face comprises a secondary bevel (5) and a tertiary bevel (6) with a second wedge angle (θ2) between the first surface on the first face and the secondary bevel and a third wedge angle (θ3) between the first surface on the first face and the tertiary bevel. Moreover, the present invention relates to a hair removal device comprising this cutting blade.

Inventors

Peter Gluche
Ralph Gretzschel
Michael Mertens

Assignees

THE GILLETTE COMPANY LLC
GFD GESELLSCHAFT FUR DIAMANTPRODUKTE MBH

Dates

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

Claims (1)

18 CLAIMS 1. A cutting blade having a first face, a second face opposed to the first face and different from the first face as well as a cutting edge at the in5 tersection of the first face and the second face, wherein • the first face comprises a first surface and a primary bevel with • the primary bevel extending from the cutting edge to the first surface, • a first intersecting line connecting the primary bevel 10 and the first surface and • a first wedge angle 1 between an imaginary extension of the first surface and the primary bevel and • the second face comprises a secondary bevel and a tertiary bevel with 15 • the secondary bevel extending from the cutting edge to the tertiary bevel, • a second intersecting line connecting the secondary bevel and the tertiary bevel, • a second wedge angle 2 between the first surface and 20 the secondary bevel and • a third wedge angle 3 between the first surface and the tertiary bevel wherein 1 > 2 and 2 < 3. 25 2. The cutting blade of claim 1, characterized in that the first wedge angle 1 ranges from 5° to 75°. 19 3. The cutting blade of claim 1 or claim 2, wherein the first wedge angle 1 ranges from 10° to 60°. 4. The cutting blade according to any one of claims 1-3, wherein the first wedge 1 ranges from 15° to 46°. 5 5. The cutting blade according to any one of claims 1-4, wherein the first wedge angle 1 ranges from 20° to 45°. 6. The cutting blade according to any one of claims 1-5, wherein the second wedge angle 2 ranges from -5° to 40°. 7. The cutting blade according to any one of claims 1-6, wherein the sec10 ond wedge angle 2 ranges from 0° to 30°. 8. The cutting blade according to any one of claims 1-7, wherein the second wedge angle 2 ranges from 5° to 25°. 9. The cutting blade according to any one of claims 1-8, wherein the third wedge angle 3 ranges from 1° to 60°. 15 10. The cutting blade according to any one of claims 1-9, wherein the third wedge angle 3 ranges from 10° to 55°. 11. The cutting blade according to any one of claims 1-10, wherein the third wedge angle 3 ranges from 19° to 46°. 12. The cutting blade according to any one of claims 1-11, wherein the 20 third wedge angle 3 is 45°. 13. The cutting blade according to any one of claims 1-12, characterized in that the primary bevel has a length d1 being a dimension projected onto the imaginary extension of the first surface taken from the cutting edge to the first intersecting line from 0.1 to 7 µm. 25 14. The cutting blade of claim 13, wherein d1 is from 0.5 to 5 µm. 15. The cutting blade of claim 13 or claim 14, wherein d1 is from 1 to 3 µm. 16. The cutting blade of any one of claims 1 to 15, characterized in that a dimension projected onto the first surface and/or the imaginary extension of the first surface taken from the cut5 ting edge to the second intersecting line has a length d2 which ranges from 1 to 150 µm. 17. The cutting blade of claim 16, wherein d2 ranges from 5 to 100 µm. 18. The cutting blade of claim 16 or claim 17, wherein d2 ranges from 10 to 75 µm. 10 19. The cutting blade according to any one of claims 16-18, wherein d2 ranges from 15 to 50 µm. 20. The cutting blade according to any one of claims 1-19, characterized in that the cutting blade comprises or consisting of a blade body consisting of a first material or comprises or consists of a 15 blade body comprising or consisting of a first material and a second material joined with the first material. 21. The cutting blade of claim 20, characterized in that the first material comprises or consists of a material selected from the group consisting of 20 • metals, • ceramics comprising at least one element selected from the group consisting of carbon, nitrogen, boron, oxygen and combinations thereof, • glass ceramics, 25 • composite materials made from ceramic materials in a metallic matrix, • hard metals, 21 • silicon or germanium, • single crystalline materials, • glass or sapphire, • polycrystalline or amorphous silicon or germanium, 5 • mono- or polycrystalline diamond, diamond like carbon (DLC), adamantine carbon and • combinations thereof. 22. The cutting blade of claim 21, wherein the metal is at least one of titanium, nickel, chromium, niobium, tungsten, tantalum, molybdenum, 10 vanadium, platinum, germanium, iron, and alloys thereof. 23. The cutting blade of claim 21, wherein the metal is steel. 24. The cutting blade according to any one of claims 21-23, wherein the ceramic comprises at least one of silicon carbide, zirconium oxide, aluminum oxide, silicon nitride, boron nitride, tantalum nitride, TiAlN, 15 TiCN, and TiB2. 25. The cutting blade according to any one of claims 21-24, wherein the glass ceramic is an aluminum-containing glass-ceramics. 26. The cutting blade according to any one of claims 21-25, wherein the hard metal is sintered carbide hard metal. 20 27. The cutting blade of claim 26, wherein the hard metal is tungsten carbide or titanium carbide bonded with cobalt or nickel. 28. The cutting blade according to any one of claims 21-27, wherein the silicon or germanium has a crystalline plane parallel to the second face, wafer orientation <100>, <110>, <111> or <211>. 25 29. The cutting blade according to any one of claims 20-28, characterized in that the material of the second material comprises or 22 consists of a material selected from the group consisting of • oxides, nitrides, carbides, borides, • boron aluminium magnesium, • carbon, and 5 • combinations thereof. 30. The cutting blade of claim 29, wherein the nitrides are at least one of aluminum nitride, chromium nitride, titanium nitride, titanium carbon nitride, titanium aluminum nitride, and cubic boron nitride. 31. The cutting blade of claim 29 or claim 30, wherein the carbon is at 10 least one of diamond, poly-crystalline diamond, nano-crystalline diamond, and diamond like carbon (DLC). 32. The cutting blade according to any one of claims 20-31, characterized in that the second material fulfills at least one of the following properties: 15 • 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, and • a hardness of at least 20 GPa. 33. The cutting blade of claim 32, wherein the thickness is from 2 to 15 20 µm. 34. The cutting blade of claim 32 or claim 33, wherein the thickness is from 3 to 12 µm. 35. The cutting blade according to any one of claims 32-34, wherein the modulus of elasticity is less than 900 GPa. 23 36. The cutting blade according to any one of claims 32-35, wherein the modulus of elasticity is less than 750 GPa. 37. The cutting blade according to any one of claims 32-36, wherein the transverse rupture stress σ0 is at least 2.5 GPa. 5 38. The cutting blade according to any one of claims 32-37, wherein the transverse rupture stress σ0 is at least 5 GPa. 39. The cutting blade according to any one of claims 20-38, characterized in that the material of the second material is nanocrystalline diamond and fulfills at least one of the following properties: 10 • 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. 40. The cutting blade of claim 39, wherein the average surface roughness RRMS is less than 50 nm. 15 41. The cutting blade of claim 39 or claim 40, wherein the average surface roughness RRMS is less than 20 nm. 42. The cutting blade according to any one of claims 39-41, wherein the average grain size d50 of the nano-crystalline diamond is from 5 to 90 nm. 20 43. The cutting blade according to any one of claims 39-42, wherein the average grain size d50 of the nano-crystalline diamond is from 7 to 30 nm. 44. The cutting blade according to any one of claims 39-43, wherein the average grain size d50 of the nano-crystalline diamond is from 10 to 20 nm. 25 45. The cutting blade according to any one of claims 20-44, characterized in that the first material and/or the second material are coated at least in regions with a low-friction material. 24 46. The cutting blade of claim 45, wherein the low-friction material is selected from the group consisting of fluoropolymers, parylene, polyvinylpyrrolidone, polyethylene, polypropylene, polymethyl methacrylate, graphite, diamond-like carbon (DLC) and combinations thereof. 5 47. The cutting blade according to any one of claims 20-46, characterized in that the first intersecting line is shaped within the second material. 48. The cutting blade according to any one of claims 20-47, characterized in that the second intersecting line is arranged at a 10 boundary surface of the first material and the second material. 49. The cutting blade according to any one of claims 20-48, characterized in that the cutting edge has a tip radius of less than 200 nm. 50. The cutting blade of claim 49, wherein the tip radius is less than 100 15 nm. 51. The cutting blade of claim 49 or claim 50, wherein the tip radius is less than 50nm. 52. The cutting blade according to any one of claims 20-51, characterized in that the secondary bevel comprises a further beveled 20 region extending from the cutting edge to a third intersecting line connecting the secondary bevel and the beveled region. 53. The cutting blade of claim 52, wherein the beveled region has a fourth wedge angle 4 between the first surface and the beveled region. 54. The cutting blade of claim 52 or 53, wherein the beveled region is 25 shaped in the second material.

Description

Cutting Blade and hair removal device The present invention relates to a cutting blade having a first face, a second face opposed to the first face and different from the first face as well as a cutting edge at the intersection of the first face and the second face. The first face comprises a first surface and a primary bevel with a first wedge angle 81 between the first surface and the primary bevel. The second face comprises a secondary bevel and a tertiary bevel with a second wedge angle 82 between the first surface on the first face and the secondary bevel and a third wedge angle 83 between the first surface on the first face and the tertiary bevel. Moreover, the present invention relates to a hair removal device comprising this cutting blade. 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 1 • The cutting bevel of a cutting blade is enclosed by the rake face and the clearance face and denoted by the bevel angle 8 • The cutting edge is the line of intersection of the rake face and the clearance face Cutting blades, in particular razor blades, are typically made out of a suitable substrate material such as stainless steel in which a symmetric wedge-shaped cutting edge is formed. With respectto razor blades, the design of the cutting blade must be optimized to find the best compromise between the sharpness of the blade and the mechanical strength and hence durability of the cutting edge. The fabrication of conventional stainless steel razor blades involves a hardening treatment of the steel substrates before the blade is sharpened from both sides to form a symmetric cutting edge usually by grinding the hardened steel substrate. A further coating may be applied to the steel blade after sharpening to optimize the mechanical properties of the blades. Hard coating materials such as diamond, amorphous diamond, diamond-like carbon (DLC), nitrides, carbides, or oxides are suitable to improve the mechanical strength of the cutting edge. Thus, the harder the cutting edge material, the longer the edge holding property and in consequence the less wear is expected. Other coatings may be applied to increase the corrosion resistance or reduce the blade friction. Most blades in the prior art are focused on blades with a symmetric blade body. However, some approaches exist where blades with an asymmetric blade are taught. In US 3,606,682, a razor blade with improved cutting ease and shaving comfort is described. The blade has a recessed portion adjacent to the cutting edge which allows an improved shaving comfort. This effect is shown for symmetric and asymmetric blade bodies. 2 . Date Reçue/Data Recieved 2024-06-19 According to the present invention a cutting blade is provided having a first face and a second face which is opposed to the first face and different from the first face as well as a cutting edge wherein • the first face comprises a first surface and a primary bevel with • the primary bevel extending from the cutting edge to the first surface, • a first intersecting edge connecting the primary bevel and the first surface and • a first wedge angle 81 between an imaginary extension of the first surface (9') and the primary bevel and • the second face comprises a secondary bevel and a tertiary bevel with • the secondary bevel extending from the cutting edge to the tertiary bevel, • a second intersecting edge connecting the secondary bevel and the tertiary bevel, • a second wedge angle 82 between first surface and the secondary bevel and • a third wedge angle 83 between the first surface and the tertiary bevel It was surprisingly found that a cutting blade with the best compromise between closeness to the surface and safety during cutting while also having a very stable cutting edge together with a very good cutting performance can be provided when the wedge angles fulfill the following conditions: The cutting blades according to the present invention have low cutting force due to a thin secondary bevel with a low wedge angle. The cutting blades according to the present invention are strengthened by adding a primary bevel with a primary wedge angle which is greater than the secondary wedge angle. The primary bevel with the first wedge angle 81 has therefore the function to stabilize the cutting edge mechanically against damage from the cutting operation which allows a slim blade body in the area of the 4 secondary bevel without affecting the cutting performance of the blade. Moreover, the primary bevel with the wedge angle 81 allows to lift the cutting edge from the surface which reduces the risk of injuring the surface and thereby increasing the safety of the cutting operation. The primary bevel with