GB983572A - Improvements in or relating to electric timer switches - Google Patents

Abstract

983,572. Time switches. CONTROLS CO. OF AMERICA. Aug. 11, 1961 [March 6, 1961], No. 29071/61. Heading H2B. The starting position of a rotary timer is set by manual rotation of a switch cam-shaft 20 until a spring-loaded stop pin 32 enters a selected hole 60 in a plate 62; the shaft is them pushed axially to disengage the pin from the plate and to close the supply switch 26 to a synchronous motor 16 which drives the camshaft for the selected programme. The pin 32 is carried on a disc 28 and co-operates with one of a number of holes 60 on a laterally movable plate 62. The plate 62 is moved by depressing a selected one of the push-buttons 75, each of which moves the plate 62 a different distance such that a different hole 60 lies in the path of revolution of the pin 32. When a button 75 is depressed a tongue 82 (Fig. 6) engages an associated cam slope (Fig. 9, not shown), in a plate 86 which is thus moved a specific distance laterally and a rack thereon turns a gear 87 rigid with gear 91 to move a rack 94 and plate 62 through an amplified distance. Plate 62 is accurately located by a tongue 96 entering an associated notch 98. Only one notch 98 can be aligned with a tongue 96 at a time and hence simultaneous operation by more than one button 75 is prevented. The push-button assembly is provided with the usual plate (Fig. 9, not shown), for latching a depressed button and releasing the previously depressed button. The initial movement of this latch plate retracts the stop-pin 32 (so that it will not interfere with the setting movement of plate 62) by camming rearwardly a retractor 44 (Figs. 6 and 7), pivoted at 46 on disc 28, its free end engaging a collar integral with pin 32. Axial movement inward of shaft 20 after rotation to the start position also depresses retractor 44. At the end of a selected programme one of the tabs 30 or disc 28 will be aligned with a cam 45 on the mounting plate (Fig. 7) and any attempt to rotate shaft 20 causes the tab to ride up on the cam, forcing the shaft outward, thereby ensuring that switch 26 is opened.