COMBINED ELECTRICAL SWITCH AND VARIABLE RESISTOR

摘要

1308443 Variable resistors JOSEPH LUCAS (INDUSTRIES) Ltd 11 June 1970 [7 July 1969] 34130/69 Heading H1S A combined switch and variable resistor comprises a (synthetic resin) casing 11 of rectangular cross-section, a plunger 14 rotatable and axially movable with respect to the casing and carrying a printed circuit board 22 mounted for rotation therewith, and a member 16 mounted for axial movement only with the plunger. Printed circuit board 22 held against axial movement by flanges 28 has printed thereon a resistance path which is engaged by wiper contacts 24 fixed in the casing and connected to terminals. A spring 27 mounted inside the casing engages depressions (25, 26) (Fig. 3, not shown) in the board 22 to define stable rotational positions of the board. The switch comprises a contact 17, spring-mounted on member 16 and movable therewith to engage fixed contacts 18 secured on the casing and connected to terminals. Balls 21 spring-loaded on member 16 engage recesses 19 in side walls 11a, 11b of the casing to retain the member in the desired axial position. Rotation of the plunger thus changes the resistance and axial movement operates the switch.