GB1210771A - Improvements in electrical switches - Google Patents

Abstract

1,210,771. Mechanical switches. W. SIEGRIST and F. SIEGRIST [trading as SIBALCO, W. SIEGRIST & Co.]. 17 June, 1969 [29 June, 1968], No. 30601/69. Heading H1N. A miniature switch comprises a printedcircuit board carrying a permanent magnet, a ferromagnetic spring blade and a ball situated intermediate the fixed and of the spring blade and the magnet, the arrangement being such that pressure on the ball from movable operating means urges the spring blade away from the magnet to actuate moving contacts on the blade with a snap action. Three main embodiments are described wherein the operating means is, respectively, a retractive push-button (Fig. 1), a push-pull button (Fig. 2, not shown) or a rotary knob (Fig. 5, not shown). In Fig. 1 a printed-circuit board 15 is secured in a cylindrical housing 11 by semi-cylindrical members 16, 17 and carries a lamp 34 a blade spring 35 secured by rivet 42, a permanent magnet 44, and a ball 45. The blade 35 acts as armature to magnet 44 and has contacts 36, 37 co-operating with contacts 40, 41. on board 15. A sleeve 25, provided with a cam 26, is movable against a spring 24 by another sleeve 27 having a translucent push-button top 30 which, when depressed, results in cam 26 forcing the ball 45 against blade 35 which is snapped away from magnet 44 to open contacts 36, 40 and close contacts 37, 41. Connections to contacts and the lamp 34 are brought out at the lower protruding end of board 15. In the modification of Fig. 2 (not shown) the sleeve 25 is dispensed with and an aperture in the upper sleeve acts directly on a larger ball (76) in this embodiment the spring 24 is replaced by a spring (69) in the button head, which spring also holds the lamp against contacts on the top end of the printedcircuit board. The button may be retained in the depressed condition by an annular external ridge (90) around the upper sleeve which interacts with a snap ring (68) accommodated in a groove on the inside of the mounting flange of the cylindrical housing. In the embodiment of Fig. 5 (not shown) the upper sleeve has no axial movement but is rotated by a knob to cam the ball (76) out of an aperture (94) to actuate the blade 35; another aperture in the sleeve but of smaller diameter than aperture (94) may receive the ball to locate an angular "operated" position of the sleeve while maintaining blade 35 away from the magnet, or the rotation of the sleeve may be limited by lugs extending therefrom and interacting with shoulders (95, Fig. 6, not shown) on a fixed sleeve (58) inside the housing.