| 摘要 |
646,342. Press-button retractive switches; mechanical switches, without quick-action. THORNYCROFT & CO., Ltd., J. I., and CLARKE, F. M. Oct. 25, 1948, No. 27683. [Class 38(v)]. A plunger - operated switch is made water-tight by a flexible sealing member 7 comprising a tubular part 7a which closely embraces the plunger 4 and an enlarged part 7c ending in a thickened rim 7d clamped to the cover 6 of the switch by a ring 8. The plunger 4 has an extension 4f carrying a conical insulating member 4d normally lying between spring contacts 2b and a conducting member 4b which is adapted to bridge contacts 2b when the plunger is pushed in, in which position the sealing member 7 is partially telescoped. The switch may be held " on " by shaping the contact 4b concavely, as shown, or may be made retractive by making the contact 4b of conical shape. Fig. 4 (not shown). The terminals 3c are separated by an extension 1e of the casing.
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