| 摘要 |
A magnetically locked fluid valve having a particular utility in a fire hydrant to prevent unauthorized usage thereof. The fire hydrant includes an operating nut mounted on top of one end of a hydrant actuator shaft, and a magnetic lock is located in immediate proximity thereto. A shaped magnet is adapted to be placed around the actuator shaft adjacent to the magnetic lock, after which a wrench can be applied to the operating nut to control operation of the fire hydrant. The magnetic lock includes magnetic tumblers which are shifted in position in response to placement of the magnet on the actuator shaft. The actuator shaft includes an upper section coupled to the operating nut and a lower section coupled to the hydrant valve. The magnetic lock is positioned between the upper and lower shaft sections, and the upper shaft section is freely rotatable relative to the lower section when the magnet is removed, but is locked relative thereto when the magnet is positioned thereon.
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