GB1425403A - Electric switch assembly - Google Patents

Abstract

1425403 Snap action switches MATSUSHITA ELECTRIC WORKS Ltd 27 April 1973 [28 April 1972 and 22 June 1972] 20193/73 Heading H1N The component parts, Fig. 3, for assembly into an insulating housing to form a pushbutton type microswitch, Fig. 2, comprise a composite actuating member 12, a support and terminal member 6, a spring 21 and two fixed terminal members 2, 4 with respective fixed contacts 3, 5. The actuating member 12 has an end portion for operating engagement by a push button 25, another end portion with movable contacts 13, 14 forming normally closed/normally open changeover with the fixed contacts 3, 5 respectively, and a central resilient portion 16 which projects from the push button end portion towards the contact end portion which has at its free end two resilient branched portions 18, 19 and a hole 17. On the underside of the support member 6 is a peg 26 which passes through the hole 17 of the actuating member 12 and the two members are secured by rivetting to give a fixed point d. The spring 21 has a slot 24 which engages a projection 15 on the actuating member and two extensions 23, 23<SP>1</SP> which are inserted in aligned notches 20, 10 & 20<SP>1</SP>, 10<SP>1</SP> respectively to form an engaging point c. On depression of the button 25 and ignoring the effect of the resilient branched portions 18, 19 the reference line a b is caused to traverse the spring stress line c d representing the line of action of spring 21 and the contacts change over with a snap action in a conventional manner (Figs 4A, B, C, not shown), there being a component force FH relating to contact pressure in both contact positions. Additionally however the branched portions 18, 19 flex to move the engaging point c so that the angle # between the actuating member 12 and the line of action of spring 21 is increased thereby increasing the component force FH as compared with the conventional arrangement denoted by dashed notation in Figs 5A, 5B (not shown).