GB1321888A - Electrical control devices - Google Patents

Abstract

1321888 Snap-action switches; ohmic resistors CTS CORP 3 July 1970 [3 July 1969] 32469/70 Headings H1N and HIS An electric switch comprises one or more bridging roller contacts 63, 64, Fig. 3, engageable across contact pairs 77a, 81a under the action of springs 62 which deflect angularly (cf "off" position shown in Fig. 8) to assist the snapaction movement of the roller contacts when the actuator 67 moves across the over-centre position. The arrangement is also stated to produce a rolling and wiping movement off the contacts. In the particular arrangement shown the rollers are engaged at two points only by the end coil 62b of each spring whereby the end coil is free to deflect angularly with respect to its normal plane at right angles to the longitudinal axis of the spring. The arrangement also permits the rollers to take up any misalignment of the contact pairs 77a or 81a and reduces contact bounce. The actuator cam 67 is of insulating material and is coupled to a shaft 43 via a headed end 56 on the shaft engageable in a slot of the cam 67. The shaft is also rotatable and keyed to a rheostat actuator 42. In a modification an actuator shaft 96, Fig. 12, is releasably coupled by a headed end 106 to engage in notches 104 of resilient arms 98, 99 of the camming actuator member 95. Alternatively the actuator shaft (117), Fig. 14 (not shown), may be of nylon and integral with the cam actuator (116a).