GB888755A - Improvements relating to push-button electric switches - Google Patents

Abstract

888,755. Switches held set and freed mechanically. JELSON ELECTRIC Ltd., and MOULSON, J. P. July 25, 1960 [Aug. 22, 1959], No. 28778/59. Class 38 (5). A push-button switch of the type having spring-loaded " on " and " off " buttons in which the ''on'' button is latched when depressed, is arranged so that the " on " button normally positively holds contacts open, allowing them to close when it is depressed, while the " off " button not only releases the latch but also positively opens the contacts. " On " and " off " buttons 5 and 6 respectively are arranged between a cover plate 2 and insulating base 1, as shown, and are urged outwardly by springs 11 and 12 respectively. A bell-crank latch member having arms 23 and 24 is pivoted at 25 in brackets 27 depending from plate 2, and carries an insulating stud 29 to engage a transverse spring blade 21 carrying a contact 20 (Fig. 4). Blade 21 urges contact 20 towards a fixed contact 19 mounted on an arm 18 having a terminal tag 17. The blade 21 is provided with a corresponding terminal tag on the opposite side of the base 1. The latch arm 23 is forked to embrace the shank 8 of " off " button 6 and apertured to allow the shank 7 of " on " button 5 to pass freely therethrough. The latch arm 24 normally rests against the lower part 14 of the shank 7 (Fig. 2) and holds the blade 21 depressed so that contacts 19, 20 are maintained open. When button 5 is depressed the end of arm 24 moves on to the shoulder 16 of shank 7, thereby latching the button 5 (Fig. 3, not shown) and allowing blade 21 to rise, closing contacts 19 and 20 (Fig. 5, not shown). When the "off" button 6 is depressed its shoulder 28 engages the forked end of arm 23 to pivot arm 24 clear of shoulder 16, releasing button 5, while the stud 29 positively opens contacts 19 and 20.