GB1237627A - Improvements relating to electrically driven dry shavers - Google Patents

Abstract

1,237,627. Dry shavers. GILLETTE INDUSTRIES Ltd. 17 March, 1970 [26 March, 1969], No. 15849/69. Heading B4B. [Also in Division H2] An electrically-driven dry shaver comprises a cutter holder 3 mounted for rectilinear reciprocating movement, the drive means for the cutter holder comprising a stationary permanent magnet system 5a, an electric coil 8b disposed in the magnetic field of that system and secured to the cutter holder for rectilinear reciprocation therewith, and means for supplying alternating electric current to the coil in order to drive the cutter holder in opposite directions alternately by the direct application of electromagnetic forces. As shown in Fig. 1 a pair of permanent magnets 5a, 5b are each secured, e.g. by adhesive, to shells 11a, 11b which are held between the halves 1, 2 of a casing made from, e.g., nylon. Washers 12 are press-fitted into each shell in order to provide air gaps 13a, 13b; the magnets are magnetized in an axial manner. Driving coils 8a, 8b are mounted on the cutter holder 3 so as to move within the air gaps under the action of springs 6, 7, the holder being slidable on a rod 4 fixed to the casing half 1. The casing contains a rechargeable battery 15, a switch 16 and a transistor oscillator and amplifier 17. In modifications, the springs 6, 7 may be replaced by annular diaphragms (Fig. 3) or leaf springs (Figs. 4 and 5). The permanent magnets may be of rectangular cross-section (Fig. 7). The shaver may also be adapted to operate from main voltage through a step-down transformer.