Barrel lock with deterrent ring and key therefor

Abstract

A barrel lock and a key for locking and unlocking the barrel lock. The lock has a hollow barrel with a plunger that reciprocates within the bore of the barrel. The plunger is urged forwardly by a bottom spring, and a deterrent ring is urged forwardly against the plunger by a top spring. The plunger has a shallow axial blind bore at its rear end and the deterrent ring has a central aperture, the diameter of the plunger bore being larger than the diameter of the ring aperture. The key has four elongated outer expanding fingers and an inner expander rod. The expanding fingers are sized and shaped so that they can pass entirely through the central aperture of the deterrent ring. When the the key is inserted into the barrel lock and the key handle is operated, the fingers radially expand and grip the inner surface of the lock plunger blind bore. As the handle is operated further, the expanding fingers longitudinally retract and draw the plunger rearwardly permitting the lock to unlock. If an unauthorized key or nail is inserted into the barrel lock, the bottom spring holds the plunger in its forward locking position as the unauthorized key or nail pulls the deterrent ring rearwardly, preventing the lock from unlocking.