| 摘要 |
An operator is slidably mounted in a guide tube and resiliently biased toward actuated position. A plurality of balls are received within radial bores in the operator which open to an axial bore. A control rod is moved within the bore to force the balls outwardly of the radial bores and into engagement with a radial shoulder of a support to retain the operator in nonactuated position. A seismic mass seats on the support and mounts a permanent magnet. The mass controls the movement of the pin out of the axial bore of the operator. The magnetic flux between the magnet and support maintains the seismic mass in seated position. An acceleration pulse of predetermined amplitude and time applied to the seismic mass tilts the mass relative to the support to move the pin out of the axial bore of the operator. When the pin is moved outwardly of the axial bore by tilting of the seismic mass, the balls are released from engagement with the support shoulder for movement within the radial bores and movement with the operator to actuated position. A manual member is movable between a first position wherein it blocks tilting movement of the seismic mass and a second position wherein it it permits such movement. In the first position the manual member completes a circuit across a source of power and a light indicating that the sensor is in inoperative condition. In the second position, the manual member does not complete the circuit.
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