| 摘要 |
A magnetic proximity sensing apparatus for sensing ferro-magnetic objects is especially well adapted for use with fluid cylinders having pistons formed from magnetically attracted material. The apparatus includes a magnetic actuator responsive to the proximity of the fluid cylinder piston or other ferro-magnetic object which closes a switch and enables electrical circuitry for controlling fluid valves or other apparatus. A reed switch mounted within a hollow, cylindrical, permanent magnet has a separate pole piece secured at one end of the reed switch. The proximity of a ferro-magnetic object changes the flux within the magnet, closing the reed switch. The circuitry is solid state and includes a silicon controlled rectifier acting as a gated switch for completing the circuit.
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