CA-3178852-C - CUTTING BLADE AND HAIR REMOVAL DEVICE

CA3178852CCA 3178852 CCA3178852 CCA 3178852CCA-3178852-C

Abstract

The present invention relates to a cutting blade (1) having an asymmetric cross-sectional shape with 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 wherein the first face comprises a surface and the second face comprises a primary bevel (5), a secondary bevel (6) and a tertiary bevel (7) with a first wedge angle (θ1) between the surface on the first face and the primary bevel, a second wedge angle (θ2) between the surface on the first face and the secondary bevel and a third wedge angle (θ3) between the 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. 5 10 15 20 25 30 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 in tersection of the first face and the second face, wherein • the first face comprises a first surface and • the second face comprises a primary bevel, a secondary bevel and a tertiary bevel with • the primary bevel extending from the cutting edge to the secondary bevel, • the secondary bevel extending from the primary bevel to the tertiary bevel, • a first intersecting line (10) connecting the primary bevel and the secondary bevel, • a second intersecting line connecting the secondary bevel and the tertiary bevel, • a first wedge angle 1 between the first surface and the primary bevel, • a second wedge angle 2 between the first surface and the secondary bevel, • a third wedge angle 3 between the first surface and the tertiary bevel, • the primary bevel having a length d1 being the dimen sion projected onto the first surface and/or an imagi nary extension of the first surface taken from the cut ting edge to the first intersecting line from 0.1 to 7 µm, • a length d2 being the dimension projected onto the first surface taken from the cutting edge to the second inter secting line from 1 to 150 µm, wherein 1 > 2 and 2 < 3. 19 2. 3. 5 10 15 20 25 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. The cutting blade according to claim 1, wherein the first wedge angle 1 ranges from 5° to 75°. The cutting blade according to claim 1 or 2, wherein the first wedge angle 1 ranges from 10° to 60°. The cutting blade according to any one of claims 1 to 3, wherein the first wedge angle 1 ranges from 15° to 46°. The cutting blade according to any one of claims 1 to 4, wherein the first wedge angle 1 ranges from 20° to 45°. The cutting blade according to any one of claims 1 to 5, wherein the second wedge angle 2 ranges from -5° to 40°. The cutting blade according to any one of claims 1 to 6, wherein the second wedge angle 2 ranges from 0° to 30°. The cutting blade according to any one of claims 1 to 7, wherein the second wedge angle 2 ranges from 5° to 25°. The cutting blade according to any one of claims 1 to 8, wherein the third wedge angle 3 ranges from 1° to 60°. The cutting blade according to any one of claims 1 to 9, wherein the third wedge angle 3 ranges from 10° to 55°. The cutting blade according to any one of claims 1 to 10, wherein the third wedge angle 3 ranges from 19° to 46°. The cutting blade according to any one of claims 1 to 11, wherein the third wedge angle 3 is 45°. The cutting blade according to any one of claims 1 to 12, wherein the primary bevel has a length d1 being the dimension projected onto the first surface and/or the imaginary extension of the first surface taken from the cutting edge to the first intersecting line from 0.5 to 5 µm. The cutting blade according to claim 13, wherein the length d1 1 to 3 µm. 20 15. 5 10 15 20 25 16. 17. 18. 19. The cutting blade according to any one of claims 1 to 14, wherein the dimension projected onto the first surface and/or the imaginary exten sion of the first surface taken from the cutting edge to the second in tersecting line has a length d2 which ranges from 5 to 100 µm. The cutting blade according to claim 15, wherein the length d2 ranges from 10 to 75 µm. The cutting blade according to claim 15, wherein the length d2 ranges from 15 to 50 µm. The cutting blade according to any one of claims 1 to 17, wherein the cutting blade comprises or consists of a blade body consisting of a first material or comprises or consists of a blade body comprising or con sisting of a first material and a second material joined with the first material. The cutting blade according to claim 18, wherein the first material comprises or consists of a material selected from the group consisting of • metals, • ceramics comprising at least one element selected from the group consisting of carbon, nitrogen, boron, oxygen and combi nations thereof, • glass ceramics, • composite materials made from ceramic materials in a metallic matrix, • hard metals, • silicon or germanium, • single crystalline materials, • glass or sapphire, 21 • polycrystalline or amorphous silicon or germanium, • mono- or polycrystalline diamond, diamond like carbon (DLC), adamantine carbon and • combinations thereof. 5 10 15 20 25 20. 21. 22. 23. 24. 25. 26. 27. 28. The cutting blade according to claim 19, wherein the metal is at least one of titanium, nickel, chromium, niobium, tungsten, tantalum, mo lybdenum, vanadium, platinum, germanium, iron, and alloys thereof. The cutting blade according to claim 19, wherein the metal is steel. The cutting blade according to any one of claims 19 to 21, wherein the ceramics comprise at least one of silicon carbide, zirconium oxide, alu minum oxide, silicon nitride, boron nitride, tantalum nitride, TiAlN, TiCN, and TiB2. The cutting blade according to any one of claims 19 to 22, wherein the glass ceramics are aluminum-containing glass-ceramics. The cutting blade according to any one of claims 19 to 23, wherein the hard metals are sintered carbide hard metals. The cutting blade according to claim 24, wherein the sintered carbide hard metals are tungsten carbide or titanium carbide bonded with co balt or nickel. The cutting blade according to any one of claims 19 to 25, wherein a crystalline plane of the silicon or the germanium is parallel to the sec ond face. The cutting blade according to any one of claims 19 to 26, wherein a wafer orientation of the silicon or the germanium is <100>, <110>, <111>, or <211>. The cutting blade according to any one of claims 18 to 27, wherein the second material comprises or consists of a material selected from the group consisting of 22 • oxides, nitrides, carbides, borides, • boron aluminum magnesium, • carbon, and • combinations thereof. 5 10 15 20 25 29. 30. 31. 32. 33. 34. 35. The cutting blade according to claim 28, wherein the oxides, the ni trides, the carbides, and the borides are at least one of aluminum ni tride, chromium nitride, titanium nitride, titanium carbon nitride, tita nium aluminum nitride, and cubic boron nitride. The cutting blade according to claim 28 or 29, wherein the carbon is at least one of diamond, poly-crystalline diamond, nano-crystalline dia mond, and diamond like carbon (DLC). The cutting blade according to any one of claims 18 to 30, wherein the second material fulfills at least one of the following 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. The cutting blade according to claim 31, wherein the thickness is 2 to 15 µm. The cutting blade according to claim 31, wherein the thickness is 3 to 12 µm. The cutting blade according to any one of claims 31 to 33, wherein the modulus of elasticity is less than 900 GPa. The cutting blade according to any one of claims 31 to 33, wherein the modulus of elasticity is less than 750 GPa. 23 36. 37. 5 10 15 20 25 38. 39. 40. 41. 42. 43. 44. 45. The cutting blade according to any one of claims 31 to 33, wherein the modulus of elasticity is less than 500 GPa. The cutting blade according to any one of claims 31 to 36, wherein the transverse rupture stress σ0 is at least 2.5 GPa. The cutting blade according to any one of claims 31 to 36, wherein the transverse rupture stress σ0 is at least 5 GPa. The cutting blade according to any one of claims 18 to 38, wherein the second material comprises or consists of nano-crystalline diamond and fulfills at least one of the following properties: • 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. The cutting blade according to claim 39, wherein the average surface roughness RRMS is less than 50 nm. The cutting blade according to claim 39, wherein the average surface roughness RRMS is less than 20 nm. The cutting blade according to any one of claims 39 to 41, wherein the average grain size d50 of the nano-crystalline diamond is from 5 to 90 nm. The cutting blade according to any one of claims 39 to 41, wherein the average grain size d50 of the nano-crystalline diamond is from 7 to 30 nm. The cutting blade according to any one of claims 39 to 41, wherein the average grain size d50 of the nano-crystalline diamond is from 10 to 20 nm. The cutting blade according to any one of claims 18 to 44, wherein the first material and/or the second material are coated at least in regions with a low-friction material. 24 46. 5 10 15 20 47. 48. 49. 50. 51. 52. 53. The cutting blade according to claim 45, wherein the low-friction mate rial is selected from the group consisting of fluoropolymers, parylene, polyvinylpyrrolidone, polyethylene, polypropylene, polymethyl meth acrylate, graphite, diamond-like carbon (DLC) and combinations thereof. The cutting blade according to any one of claims 18 to 46, wherein the first intersecting line is shaped within the second material. The cutting blade according to any one of claims 18 to 47, wherein the second intersecting line is arranged at a boundary surface of the first material and the second material. The cutting blade according to any one of claims 18 to 48, wherein the cutting edge has a tip radius of less than 200 nm. The cutting blade according to claim 49, wherein the tip radius is less than 100 nm. The cutting blade according to claim 49, wherein the tip radius is less than 50 nm. The cutting blade according to any one of claims 18 to 51, wherein the first face comprises a first surface which is planar. The cutting blade according to any one of claims 18 to 52, wherein the first face further comprises a quaternary bevel extending from the cut ting edge to the first surface.

Description

1 Cutting Blade and hair removal device The present invention relates to a cutting blade having an asymmetric crosssectional shape with a first face, a second face opposed to the first face and different from the first face as well as a cutting edge wherein the first face comprises a surface and the second face comprises a primary bevel, a secondary bevel and a tertiary bevel with a first wedge angle 81 between the surface on the first face and the primary bevel, a second wedge angle 82 between the surface on the first face and the secondary bevel and a third wedge angle 83 between the 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 2 • 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 respect to razor blades, the design of the cutting blade has to 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. 3 US 3,292,478 describes a cutting die knife for textiles, leather and similar sheet materials wherein the knife has suitably inclined surfaces on both sides with the consequence that the cutting edge is not positioned centrally between the side surfaces and the knife has an asymmetric shape. US 3,514,856 refers to a razor blade construction having defined angular and dimensional limits of the converting surfaces from the cutting edge and an effective recessed portion immediately adjacent thereto from proved cutting ease and shaving comfort. There is a continuing desire to reduce the force needed to cut an object, since this requires less energy and creates less wear of the cutting edge. In the context of shaving, cutting hairs at lower forces results in less pulling on the hairs and hence less discomfort. A reduction of the cutting force is achieved by reducing the angle of the wedgeshaped cutting tool. However, making the edge sharper also makes it more fragile and despite the application of hard coatings, the durability of conventional steel razor blades is still limited today. The present invention therefore addresses the mentioned drawbacks in the prior art and to provide cutting blades with a design which allow at the same time, a high comfort during the cutting process, i.e. a low cutting force, and a high durability, i.e. a low fragility of the blade. The term "comprising" in the claims and in the description of this application has the meaning that further components are not excluded. Within the scope of the present invention, the term "consisting of' should be understood as preferred embodiment of the term "comprising". If it is defined that a group "comprises" at least a specific number of components, this should also be understood such that a group is disclosed which "consists" preferably of these components. ) . jected onto the first surface and/or the imaginary extension of the first surface taken from the cutting edge to the first intersecting line from 0.1 to 7 μm, 6 second wedge angle 82. The third wedge angle 83 represents the splittin