GB984791A - Improvements in dry shavers - Google Patents

Abstract

984,791. Dry shavers. NEEDLE INDUSTRIES Ltd. June 30, 1961 [June 30, 1960], No. 22860/60. Heading B4B. In a dry shaver comprising an apertured guard plate 10 and a motor-driven cutter member 14 which includes at least one cutting blade 16 in the form of a concave shell or ring having a curved cutting edge 29 defined by the meeting at an acute angle of the outer face 28 of the shell and a contact face 27, the blade being biased by a spring 25 to urge the contact face against the inner face 13 of the guard plate and being moved along a predetermined orbital path when the cutter member is driven, the guard plate and the blade are thin-walled so that, due to low inertia, the blade can follow deflections of the guard plate resulting from contact with the skin and the blade, mounted on a carrier forming part of the cutter member by fastening means which prevent separation of the blade and carrier but allow the blade to rotate and rock relatively to the carrier, remains in contact with the inner face of the guard member during deflection thereof. The guard plate is of plain carbon or alloy steel and has apertures 37 which diverge towards the outer face 11 so that skin protrudes thereinto, the walls 38 of the apertures being frusto-conical, concave or convex. The cutter member comprises a carrier 15 detachably mounted on a drive spindle 17 and having high carbon or alloy steel cutting blades, of thickness of between 0À003 and 0À005 inch, each secured thereon by a hollow spigot 30 formed integral with the carrier and through which passes a shank having heads 33, 34 which are spaced to allow rocking and floating of the blades. The blades are pressed from sheet steel and have a narrow face 28a making a steeper angle with the plane of the guard plate than the outer surface 28. The contact surface 27 is preferably lapped on a spherical abrasive surface to form a sharp cutting edge 29. Apertures 36 are provided for the escape of cut hair. In use, the blades rotate on their axes due to friction to provide constant lapping and in modifications with no apertures 36 cut hair escapes between the trailing edge of the blade and the guard plate. In further modifications, the generatrix of the blade is curved and the outline elliptical or fluted, the inner and outer walls of the blade are not parallel, the centre of gravity is offset from the axis 26, and the blades move in different orbits, or the trailing edge of the blade is formed by a stabilizing pad. According to the Provisional Specification, the carrier member is retained on the drive spindle by an elastic, synthetic resin plug having a shank entering a bore in the spindle, the spindle has a cut-away portion forming a part of non- circular section in driving engagement with the carrier and of greater axial length than the thickness of the carrier, and the carrier is in the form of a spider carrying more than two blades and has apertures in which the apices of the blades seat. Specification 984,793 is referred to.