GB1429768A - Snap-action electric switch - Google Patents

Abstract

1429768 Retractive switches; snap-action BURGESS MICRO SWITCH CO Ltd 5 Sept 1973 [9 June 1972] 27145/72 Heading H1N In the snap-acting switch of Fig. 1, a first movable contact arm 6 pivoted to an anchor member 2 and carrying a contact 20 normally engaged with a terminal arm 22 is held in this, rest, position by a spring 14 and an electrical circuit is provided through to terminal arm 4 of the anchor member 2. A second movable contact arm 24 of resilient strip material 28 having one end 30 riveted or welded to a terminal arm 26 carries a contact 32 and is biased downwardly into the rest position shown in which its free end 40 abuts the lower surface of a groove 38 in an insulating member 36 which depends from the contact 20. An actuator button 18 engages the spring 14 intermediate of the end 16 and the turned up legs 12 of the anchor member 2, and on deflection of the spring to an overcentre position the contact arm 6 is displaced with a snap-action to disengage contact 20 which, through its linkage to the second arm 24 through the insulating member 36, then causes this second arm to flex so that its contact 32 engages a further terminal arm 34 and thereby provides a second independent electrical circuit through the switch. In an alternative arrangement of Fig. 1 the free end 40 of the second contact arm 24 may be biased upwardly to its rest position in which case the two contact arms 6, 24 are displaced together throughout the snap-action. In another embodiment (Fig. 2, not shown) the insulating member 36 is dispensed with and the second contact arm 24 carries an insulating block 42 biased into engagement with contact 20 of the first contact arm. All contacts return to the rest position shown on release of the actuator button 18.