| 摘要 |
1435492 Snap-action switches; actuating devices for switches J A CRABTREE & CO Ltd 9 May 1973 [17 May 1972] 23172/72 Heading H1N In a rocker operated switch in which a moving contact 23 is operated by a spring-loaded plunger in a bore in the rocker 13, the crosssectional dimensions of the plunger and bore in the plane of movement of the rocker allow an increment of angular movement of the plunger additive to that of the rocker during operation of the switch. As shown, moving contact 23 pivots on dimples 27a and the plunger terminates in a point 17a. The greater angular movement of the plunger is achieved by the plunger being of constant cross-section along its length and the bore widening towards its mouth, e.g. it may be of tapered oval shape. In the closed position shown, end 17a rests on contact 23 on one side of dimples 27a and the plunger is against the side of the bore. As rocker 13 is moved clockwise it pushes the plunger so that end 17a moves along contact 23 until it is over dimples 27a. Further movement of rocket 13 pushes end 17a along contact 23 until end 17a moves past dimples 27a and the spring loading the plunger snaps constact 23 open from fixed contact 20 and the plunger moves against the opposite side of the bore. Further movement of rocker 13 allows the spring in the bore to urge end 17a further down contact 23. Thus the plunger travels a greater angular distance than the rocket 13. The bore may be of constant cross-section and the plunger tapered, or both may be of constant cross-section with a lateral clearance, the spring loading the plunger being centred by a peg on the blind end of the bore. The rest of the switch is as that described in Specification 921,819. |
