GB1415855A - Snap-action electric switches - Google Patents

Abstract

1415855 Retractive switches; contact arms BURGESS MICRO SWITCH CO Ltd 9 Feb 1973 [13 March 1972] 11633/72 Heading H1N A snap-action switch, Fig. 3, includes a movable contact arm 6, such as Fig. 1 or 2, which is pivoted at one end to an anchor terminal 4 and has a plurality of elements at its other end adapted for make or break with fixed contact members 22, 24 upon depression of an actuator button 20 which deflects a tension spring 12 to give a retractive changeover snap action. The elements at the free end of the arm may be formed by photographic etching and may be offset to opposed sides of the central plane of the arm by bowing, typically as Fig. 2, or bending (Fig. 5, not shown) and such offsets may be variously arranged including one (Fig. 6, not shown) in which the outward extent of the offset is greatest at the central element and reduces towards the side edges. The free ends of the fixed contacts co-operating with the multielements of the contact arm may also be shaped in a prescribed manner with the object of improving conductivity and lessening contact bounce e.g. by being bent down so as to provide edge engagement with the elements. In another embodiment (Fig. 4, not shown) the elements are coplanar with the contact arm and the associated fixed contacts have their ends pre-shaped, generally convex towards the arm, with partspherical, or V-shape sections.