GB1446460A - Electric changeover switch device - Google Patents

Abstract

1446460 Selector switch SAN-ESU TOKO Inc 5 Nov 1973 [11 Nov 1972] 51280/73 Heading H1N A changeover switch has three main fixed contacts 11a, 11b, 11c and two auxiliary fixed contacts 12a, 12b and two respective moving contacts 13, 16, mounted on a rectilinearly reciprocable slide member (15) the arrangement being such that as the slide 15 moves from one end position to the other, the main moving contact 13 bridges the centre main fixed contact and alternatively one or other outer main fixed contact 11b, 11c one pair being unbridged before the other pair is bridged, and the auxiliary moving contact 16 bridges the two auxiliary contacts 12a, 12b during the changeover periods, from immediately before break to immediately after make of the main contacts, the contacts 12a, 12b being unbridged on full making of the main contacts. Further sets of main contacts may be provided along the switch and sets of main and auxiliary contacts may be provided on opposite sides of the casing, as in Fig. 2. Terminal tags (Fig. 1, not shown) extend out of the casing to facilitate fixing, together with other switches, on a printed circuit board (Fig. 7, not shown). The auxiliary contacts 12a, 12b may have a greater width (in the direction of reciprocation of slide 15) than the spacing between the main contacts 11a, 11b, 11c. If the auxiliary contacts are narrower than this, the corresponding moving contact 16 has an appropriately wider contact surface (Fig. 5, not shown). To prevent bounce of the moving contact 16, auxiliary contacts 12a, 12b may be levelled on adjacent sides (Fig. 8a, not shown) or an idle contact (22, Fig. 8b, not shown) or a casing extension (10a, Fig. 8c, not shown) may be provided.