GB1515247A - Electric snap action switch - Google Patents

Abstract

1515247 Snap-action switches ITT INDUSTRIES Inc 13 July 1976 [16 July 1975] 29113/76 Heading H1N A snap-action switch comprises an arched sheet metal contact 1, Fig. 1, which when depressed centrally, snaps about a line transversely of the arch axis and engages contact springs 22, 32 in the form of cantilever wires or sheet metal strips. The contact 1 is engaged by a domed membrane actuator 51 and may have a recess 11 in the contact region. A terminal tag 12 at the end of the contact 1 engages in a recess 67 in the switch base 6 for pressure contact with a U-shaped terminal wire 4. Both contact springs 22, 32 also have integral terminal ends 2, 3, for extension through slots 63, 64 in the base 6 and retention by the cover 8 when fitted as by deforming extensions 68 on the base 6 over holes 82 on the cover. The contact springs 22, 32 may extend freely across the base 6 or may be engaged under stops (69), Fig. 3 (not shown) to provide a pre-tension. In a modification the contact wires may be replaced by strip metal contacts (24, 34), Fig. 6 (not shown), with integral terminals and the arched sheet metal contact may also have integral terminal lugs. In a further embodiment the contact 1 may be arranged to initially engage an additional contact 23, Fig. 5, at its end remote from the fixed connection to its end terminal 33 and engages a projection 70 when depressed by the actuator 5 so that it lifts off the contact 23. The arrangement is such that the normally closed contact at terminal end 23 opens prior to the circuit being closed between the central contacts 22, 32.