GB808458A - Improvements in snap-action electric switches - Google Patents

Abstract

808,458. Snap-action switches. ALBERT, P. L. L. Jan. 7, 1957 [Jan. 6, 1956], No. 586/57. Class 38 (5). In a switch operable by successive similar operations of a push button, the latter bears on one or other of two surfaces on an intermediate member which is adapted to turn about a pivot which is in turn adapted to swing about a fixed axis, a dead centre spring being attached at one end to the intermediate member and at the other end to a pivoted contact adapted to swing between two fixed contacts. In one form, Fig. 1, the movable contact 4 is U-shaped and is pivoted by knife edges 5, the spring 13 being hooked in an aperture 14 at one end and in the bottom 15 of a cut-out in the intermediate member 12. The latter is pivoted by a knife edge 11 on a U-shaped control member 7 itself pivoted at 8, the pivots 5 and 8 being formed in a part attached to a terminal 1. Assuming the switch to be in the position shown, depression of push button 21 causes the intermediate member to tilt about the pivot 11 to carry the spring across dead centre and change contact 4 over from terminal 2 to terminal 3. After release of the button, the member 12 tilts back slightly to bring edge 11 and points 14, 15 into line and then the member 7 itself swings clockwise about the pivot 8 so that the parts are arranged in the opposite position to that shown, ready for the next operation. In Fig. 3, the intermediate member 31 pivots about a spindle 32 in arcuate slots 33 in the walls of a U-shaped member 30, the arrangement being such that after the contacts have changed over and the push button has been released, the spindle 32 moves to the opposite end of slots 33. In a further arrangement, Fig. 6, the tension spring 13 is replaced by a compression spring 40, and the spindle 32 is located against the upper edges of apertures 47 in the member 30.