Matsushita Electric Works, Ltd.

Other

Osaka Prefecture

Tadashi Hamada

Shuji Yamada

Shigetoshi Sakon

Shinji Fujimoto

Junji Imai

Toshio Ikuta

Eiji Tsuji

Tomoyuki Mizukoshi

Hiroshi Yamada

Fumio Iwane

Masao Tanahashi

Shunsuke Komori

Hiroaki Yoshida

Masakatsu Araki

Hiroyuki Kameoka

Hajime Kojima

Takashi Kozai

Masaaki Satou

A razor blade is provided, which achieves improved safety in use and reduced cutting resistance to an object to be cut such as beard and hair, as compared with conventional razor blades. This razor blade can be obtained by using, as a silicon thin sheet, a single crystal silicon material such as Si wafer or a polycrystalline silicon material including relatively large silicon crystal grains, forming at least one opening in the silicon thin sheet by chemical etching, and forming a cutting edge made of silicon single crystal by ion beam etching without machining such that the cutting edge projects into the opening and has a nose radius of 0.5 &#x3bc;m or less, and preferably 0.1 &#x3bc;m or less.

Razor blade

An inner cutter for a dry shaver has a plurality of bladessupported on a baseand is driven in hair-shearing engagement with an outer cutterfor cutting the hairs. The bladesare arranged in parallel with each other and are each provided on opposite sides at its top with cutting edges. The cutting edgeis defined between the top face of the blade and a rake fadeon the underside of the blade. The rake faceis inclined with respect to the top face at an angle of &#x3b1; (&#xb0;), while the cutting edge is rounded at its tip to have a curvature radius R (&#x3bc;m) which satisfies a relation that R&#x2267;&#x2212;0.067&#xb7;&#x3b1;+4.7. With this result, the cutting resistance for cutting the hair can be lowered below a load necessary for bending the hair. Thus, the blade of the inner cutter can itself cut the hair without bending the hair, giving a flat cutting plane finish and enabling a close shave only with a fewer shaving strokes.

Electric razor inner blade unit

A blade of an electric shaver is disclosed. The blade includes an interior blade detachably attached to a drive element of the electric shaver via an interior blade pushing-up means. The interior blade includes a horizontal surface, a vertical surface, and a relief surface provided between the horizontal surface and the vertical surface, and is elastically pushed upward by the interior blade pushing-up means. The blade further includes a sheet-shaped exterior blade having a plurality of blade apertures. A bottom surface of the exterior blade is elastically contacted with the horizontal surface of the interior blade by a pushing force of the interior blade pushing-up means. Upon driving the drive element, the interior blade is moved laterally such that the horizontal surface of the interior blade rubs against the bottom surface of the exterior blade, and hair introduced into the blade aperture of the exterior blade is held between the horizontal surface of the interior blade and the exterior blade in accordance with a lateral movement of the interior blade and cut by an edge of the exterior blade.

Blade of electric shaver, method for shaving by using the same, and electric shaver having the same

An intermetallic-compound coated stainless steel having excellent rigidity, toughness, wear resistance and corrosion resistance comprises a substrate of a martensite stainless steel having a Vickers hardness of 400 or more, and a hard film having a bottom surface adhered to the substrate and an exposed top surface. The hard film has an outermost layer made of a compound selected from the group consisting of a Ti&mdash;Ni intermetallic compound, Ti&mdash;Fe intermetallic compound, and a mixture of the Ti&mdash;Ni intermetallic compound and a Ti&mdash;Cu intermetallic compound. The coated stainless steel can be produced by cladding an outer sheet made of Ti or a Ti alloy to a martensite stainless steel sheet directly or through an intermediate sheet made of Ni, Fe or a Ni&mdash;Cu alloy, heating the laminate at a temperature of 900&deg; C. to 1150&deg; C. for 30 seconds to 5 minutes, and then cooling the heated laminate at a cooling rate of 1&deg; C./sec or more.

Stainless steel coated with intermetallic compound and process for producing the same

A ferrous alloy is formed with a Fe--Cr stainless steel having a Vickers hardness of 400 or more as a substrate and a Fe--Al diffusion layer having a thickness of 2 to 50 .mu.m. The diffusion layer contains at least 90 vol % of an intermetallic compound of Al and Fe relative to a total volume of the diffusion layer. The Al content included within a depth of at least 2 .mu.m of the diffusion layer is 35 to 65% by weight based upon total weight of a region of the diffusion layer ranging up to the thickness of at least 2 .mu.m. It is preferred to use as the substrate a precipitation-hardening stainless steel comprising 66 to 81.9 wt % of Fe, 15 to 20 wt % of Cr, 3 to 13 wt % of Ni, and one element selected from 3 to 6 wt % of Cu, 0.5 to 2 wt % of Al, and 0.01 to 0.2 wt % of a total of C and N, or a high carbon stainless steel comprising 73 to 89.9 wt % of Fe, 10 to 19 wt % of Cr, 0.1 to 1.2 wt % of C, and less than 3 wt % of Ni. The ferrous alloy may be used for sliding parts such as gears or bearings, and blades of electric shavers or hair clippers.

Ferrous alloy with Fe-Al diffusion layer and method of making the same

A cutting device for an electric shaver comprising an outer cutter and a plurality inner blades that are made of a ferrous alloy comprising a substrate of an Fe-Cr stainless steel and a hardened layer of improved hardness and wear resistance. The substrate has a Vickers hardness of 400 or more. The hardened layer has a Vickers hardness of at least 700 and a thickness of 2 to 15 .mu.m. In particular, it is preferred that the hardened layer is a diffusion layer comprising at least 90 vol % of intermetallic compounds of Al and Fe relative to a total volume of the diffusion layer, and Al content included within a depth of at least 2 .mu.m of the diffusion layer is 35 to 65% by weight based upon total weight of a region of the diffusion layer ranging up to the thickness of at least 2 .mu.m. When the ferrous alloy is polished to form the outer cutter and inner blades, it is possible to provide sharp cutting edges of the outer cutter and inner blades, while preventing the occurrence of burrs or micro-chippings at the cutting edges.

Cutter combination for an electric shaver

Fe-Cr-Ni-Al ferritic alloy capable of forming hot oxidation/corrosion resistive aluminum oxide scale in the surface thereof by exposure to oxidation environments at elevated temperatures. Due to the ferritic structure, the aluminum oxide scale is formed uniformly and densely to improve scale adherence, or prevent scale flaking. The mechanical properties of the ferritic alloy is considerably improved by incorporation of controlled amounts of Cr, Ni, and Al relative to each other, which are added to precipitate minute Ni-Al intermetallic compounds in the alloy matrix while retaining the ferritic structure. Such minute Ni-Al intermetallic compounds are thought to be responsible for improved mechanical properties, including high temperature strength, tensile strength, hardness and the like. Whereby, the alloy combine excellent hot oxidation/corrosion resistance and improved mechanical properties.

Process of preparing Fe-Cr-Ni-Al ferritic alloys

A ferritic alloy with a wear resistive oxide scale is obtained through the steps of pressing a ferritic alloy powder containing aluminum into a powder compact of a desired configuration, sintering the powder compact in a non-oxidizing atmosphere to provide a resulting sintered product, and heat-treating the sintered product in an oxidizing gas atmosphere in order to precipitate in the surface thereof alumina in the form of an alumina scale as the wear resistive oxide scale which is responsible for improved surface hardness or wear resistance. Due to the inherent porous nature of the sintered product, the oxidizing gas can readily penetrate deep into the surface of sintered product to facilitate the oxidization of the product surface into the alumina scale, in addition to that the oxidization depth can be controlled such as by the density of the product, which makes it possible to readily control the thickness of the alumina scale. The resulting alumina scale has an improved scale adherence due to the ferritic structure of the alloy.

Growing community of inventors

Sakai, Japan

Tadashi Hamada