GB1130161A - Improvements relating to automatic control mechanism - Google Patents

Abstract

1,130,161. Time switches. HOOVER Ltd. 17 Jan., 1966 [22 Jan., 1965], No. 2959/65. Heading H1N. In an automatic control mechanism including a programme cam (20), (Fig. 3, not shown), a stepping mechanism (Fig. 3, not shown), and a timing mechanism, Fig. 2, including a timing cam 44 movable against a return spring 63 to successively actuate timing contacts 70-75 via a cam follower 69, the cam 44 is driven by a gear 43 through a torsion spring 85 which is first strained and then released so that cam 44 actuates its timing contacts with a snap-action at the end of each timed interval. Cam 44 has spaced stop shoulders 101-105 engaged by a fixed pawl 100, and gear 43 has a cam surface (90) with spaced cam rises 91-95 which move the pawl 100 clear of each stop shoulder at the end of each timed interval. A release can (54) rocks a lever (65), (Fig. 1, not shown) to disengage a pinion 42 from the timing gear 43 to allow gear 43, with cam 44, to be returned by spring 63 to its initial position. This position is determined by a spring-urged movable buffer stop (131) which is engageable by a detent 86 of cam 44, which detent passes through an arcuate slot 87 of gear 43 (see also Figs. 8-10, not shown), unless a cam (61) moves the stop (131) clear of the detent.