| 摘要 |
A housing supports a seismically responsive switch mechanism having an annular contact ring defining a center aperture within which a contact weight is resiliently supported by a flexible spring rod. A silicon-controlled rectifier is operatively coupled to a DC power input and power output coupling to provide electrical power coupling therebetween when the silicon-controlled rectifier is triggered. The trigger voltage for the silicon-controlled rectifier is provided by a circuit path which includes the annular ring and contact weight. The contact weight defines a frusto-conical outer surface and a ring positioning apparatus supports the ring at different positions with respect to the contact weight to provide different distances between the contact weight and the ring. In one embodiment, the ring positioning apparatus includes a rotatable shaft and a gear coupling which drives a threaded support to raise or lower the contact ring with respect to the contact weight. In an alternate embodiment, the ring is supported by a vertically movable shaft. In a still further alternate embodiment, a pair of seismically responsive switch mechanisms are selectable using a selector switch.
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