| 摘要 |
An article anti-theft device has a pair of hinged components that are detachably clamped together about a shaft of an article intended to be protected. The shaft is clamped between the two components with a selected one of the components having a resiliently mounted elongated prong insertably received within the other component and is held thereto by a ball clutch mechanism which includes a tapered housing with an internal tapered wall surface enclosing a plug member having at least two balls carried in opposing seats in the tapered housing and the plug member and a coaxial passageway insertably receives the elongated prong. The plug member is resiliently biased to a first position by an expansion spring causing the balls to bear against the tapered inner wall of the housing, restricting the passageway. When the prong occupies the passageway, the balls are forced outwardly as the plug member moves to compress the spring. The widened mouth of the housing permits the balls to expand and does not place any restriction on the prong. Should the first component with the prong be withdrawn by unauthorized personnel, the plug member will be pushed into the tapered recess of the housing by expansion of the spring and the balls will contract and restrict the prong of the first component, so as to hold the pair of components together. Both components are attached to hinged, mated halves of a clamp member having an open-ended passageway for receiving a shaft of an article to be protected. An electronic transmitter or radiation sensor is carried on the clamp member response to attempted theft in cooperation with a surveillance system.
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