GB1079522A - Improvements in or relating to timer-controlled electric switches - Google Patents

Abstract

1,079,522. Time switches. ENGEL & GIBBS Ltd. July 9, 1965 [May 5, 1964], No. 18689/64. Heading H2B. Adjustable tappets 28a, 29a and 30a, 31a driven by a synchronous motor (14) (Fig. 2, not shown) act on a nylon cradle 33 pivoted at 47 on a base-plate 18 so as to move a mercury switch (32, Fig. 1, not shown) embedded therein in clear silicon rubber (34), alternately on and off. A spring 35 urges the cradle 33 to the " off " position (Fig. 4, not shown) and the " on " tappets 28a and 30a engage an upstanding projection 46 at respective preset times to pivot the cradle into the position shown, where it is retained by the nose 42 of a pawl 38 urged by spring 40 to overlie a projection 44 on cradle 33. The " off " tappets 29a and 31a engage a part 43 of pawl 38 to release the cradle suddenly at respective preset times. A pin 49 projects forwardly from cradle 33 through a slot in a transparent cover (12, Fig. 2, not shown) for manual actuation of the switch. A day-omission star wheel 51 is stepped by " off " tappet 31a (which is longer than tappet 29a for this purpose) and screws 54 may be inserted in selected ones of seven tapped holes 53 to engage the tip 56 of pawl 38 such that the switch cannot be retained closed on the selected days.