GB1339666A - Time switches - Google Patents

Abstract

1339666 Time switches AMF Inc 19 April 1972 [4 May 1971] 13064/71 Heading H1N A setting mechanism for a time switch comprises a differential mechanism including a driven gear-wheel 26, a setting gear-wheel 15, coaxial with said driven gear-wheel and normally held stationary but rotatable to set a desired switch-operation time, and a pinion 19 in mesh with both the driven and setting gearwheels, said pinion being rotatable on a shaft 21 which is free to move about the axis of the wheels along a circular path in a plane between the driven and setting gear-wheels, said shaft serving to actuate, directly or indirectly, switch contacts. As shown the driven gear-wheel 26 has double contrate teeth and a second setting wheel 29 and pinion 27 are provided. A hexagonal shaft 10 rotates wheel 26 once in twelve hours and an indicating dial 11 may have a pin (44, Fig. 2, not shown) to step a small Geneva wheel (42) indicating A.M. and P.M. alternately. Each pinion shaft 21 and 30 has an associated projection 23 and 32 which steps a respective star wheel switching cam 24 and 33 once in twelve hours to actuate contacts-not shown. Wheels 15 and 29 are restrained in their set positions by means not shown. In another embodiment (Fig. 3, not shown) four differential mechanisms are mounted on a common shaft rotating once in twenty-four hours and each pinion (49) moves two projections (58, 59 and 60, 61) acting on respective staggered arms of a double star wheel (56, 57) to actuate change-over contacts (72, 73, 78) four times a day. The projections 23, 32 are provided with slots to avoid jamming with the star wheels. The setting gears may be moulded with contrate teeth on both sides (as in Fig. 3, not shown) to avoid having to provide special left and right hand setting wheels.