| 摘要 |
<p>1,251,958. Snap-action switches. JOSEPH LUCAS (INDUSTRIES) Ltd. 4 Feb., 1969 [16 Feb., 1968], No. 7640/68. Heading H1N. An electrical switch comprises a hollow casing 11 including a base 12, fixed contacts 14 on base 12, a movable contact 17 mounted for sliding movements relative to base 12, detent means acting between casing 11 and movable contact 17 for locating it relative to base 12 in the operating positions of the switch, an operating member 27 pivotally engaged with casing 11, means on operating member 27 for releasing the detent means during movement of the operating member, and resilient means 34, 35 acting between operating member 27 and movable contact 17, the resilient means being stressed during movement of operating member 27 and serving to move movable contact 17 when the detent means is released. The detent means comprises a roller 23 resting at its centre in a slot 22 in slider 16 which carries movable contact 17, passing through windows 29 in two arms 28 of operating member 27 and resting at its ends in depressions 21a, 21b, 21c, Fig. 5 (not shown) in the side walls of casing 11. It is stated that in the position shown movable contact 17 bridges some fixed contacts 14 which are not shown. If operating member 27 is pivoted clockwise cam surfaces 31 on the inside edges of windows 29 move roller 23 upwards until it is clear of the depressions when resilient fingers 35 on member 27 force slider 11 to the left until spring 33 urges roller 23 into the next depression. When member 27 is moved anticlockwise, slider 11 moves to the right. Casing 11, slider 16 and member 27 are of moulded synthetic resin.</p> |
