| 摘要 |
A trip valve operator for actuating quarter turn valves comprises a return actuator, multi-stage leverage means for reducing the trigger load, a trigger, and one or more sensors or other trip actuators. The multi-stage leverage means comprises pivotally connected levers in series which form a compact mechanism, variously taking the form of four bar linkage or concatenated four bar linkage, that produces high leverage and low frictional holding torques at the reset position for reliable triggering, and that accommodates quarter turn actuation and can be single action reset. The operating areas of the successive stages of leverage overlap. Other multi-stage leverage means includes a leveraging release lever in which the short leverage arm has a land which lies in a radial plane with respect to the mounting pivot thereof for engaging a previous stage of leverage. Reset is provided by arm means which re-engage near the reset position. The trip valve operator can include by-pass means comprising a two degree of freedom linkage or a floating lever. An omnidirectional, switched resonating seismic sensor and transducer is combined with the trip valve operator to form a seismic sensitive valve. The sensor comprises a mass element which can move in a horizontal plane, an omnidirectional spring network, a two degree of freedom ball bearing having means for preserving the alignment thereof, and a sliding frictional damper. The transducer converts the two degree of freedom motion of the mass element into a trigger throw and comprises a conical cam and a follower.
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