EP0327065A3 - Rotation operating device of variable resistor - Google Patents

Abstract

A rotation operating device of a variable resistor comprises; a knob (3, 31) to apply a rotating force from the outside; intermediate gears (26) to transfer the rotating force of the knob to a sliding contact of a variable resistor 5); a ring member (4); an intermediate rotating body (2); and a supporting body (1) to support them. A circular supporting concave portion (13) is formed on the supporting member. An annular groove (16) having both ends is formed on the bottom surface of the supporting concave portion. The both ends of the annular groove serves as stoppers (17). The knob has a gear (32) in its lower portion. The ring member is rotatably supported into the supporting concave portion and has a gear (41) formed on its upper inner peripheral surface and has a lower inner peripheral surface (42). The intermediate rotating body has on its upper surface a position indicating portion (24) which can be seen from the outside and has shafts (24, 25) to rotatably support the intermediate gear so as to be come into engagement with the gear of the knob and with the gear of the ring member. Further, an outer peripheral surface (27) of the intermediate rotating body is come into frictional contact with a lower inner peripheral surface (42) of the ring member. A projecting portion (23) adapted to be movably fitted into the annular groove is formed on the lower surface of the rotating body. The intermediate rotating body is in engagement with the sliding contact of the variable resistor at the center of the lower surface.