| 摘要 |
A latching solenoid is provided which has first and second coils having a central axial opening arranged to produce oppositely polarized first and second magnetic fields along the axial opening. A paramagnetic path is provided from the central opening around the outside of the coils and back to the central opening, with this path having a first gap within the central opening. A plunger is spring biased within this central opening to close the first gap upon activation of the first coil in opposition to the spring. The paramagnetic path includes at least a portion of paramagnetic material, preferably a cylindrical outer housing, which, upon activation of the first coil to develop the first magnetic field, forms a temporary permanent magnet of sufficient strength to maintain the plunger, in opposition to the spring, in closed position upon deactivation of the first coil and which, upon activation of the second coil to develop the second magnetic field is demagnetized sufficiently to permit the first spring to bias the plunger in position to open the first gap. Preferably, a second plunger is provided around the outside of the solenoid adjacent a circumferential second gap, with this second plunger spring biased in an open position and arranged to move in sympathy with movement of the first plunger.
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