초록 ▼

A lock for locking closed a housing for an alarm pull station includes a lock cam and a lock cylinder assembly. The lock cylinder assembly includes: a lock actuation cylinder having a keyhole exposed on a front side of the housing and a key actuation socket in registry with the keyhole, and a tumble

A lock for locking closed a housing for an alarm pull station includes a lock cam and a lock cylinder assembly. The lock cylinder assembly includes: a lock actuation cylinder having a keyhole exposed on a front side of the housing and a key actuation socket in registry with the keyhole, and a tumbler plate movable transversely through the lock actuation cylinder and interposed between the keyhole and the socket. The tumbler plate includes a bore which is out of registry with the keyhole and movable into registry with the keyhole by a key pushed into the keyhole. The lock actuation cylinder is rotatable by an Allen wrench key fit into the socket. The lock actuation cylinder is surrounded by a lock body which is fixed to the housing. The tumbler plate is biased to be engaged into a slot in the lock body and is moveable transversely by the key to disengage the lock body. The lock actuation cylinder rotates the lock cam for locking the base plate to the cover. The lock cylinder assembly allows opening of the housing using a commonly available Allen wrench but prevents visual inspection of the key socket, through the keyhole, to ascertain the correct size key.

대표청구항 ▼

[ The invention claimed is:] [1.]1. A pull station for an alarm, comprising:a housing including a base plate and a cover overlying said base plate;a handle mounted for movement with respect to said housing;an alarm switch within said housing which is activated by movement of said handle to place the

[ The invention claimed is:] [1.]1. A pull station for an alarm, comprising:a housing including a base plate and a cover overlying said base plate;a handle mounted for movement with respect to said housing;an alarm switch within said housing which is activated by movement of said handle to place the pull station in an alarm mode;a latch activated by movement of said handle to move to a latched position to prevent reverse movement of said handle;a lock carried by said cover and arranged to lock said cover to said base plate, wherein said lock comprises a lock cam and a lock cylinder assembly, the lock cylinder assembly havinga lock actuation cylinder having a keyhole at one end thereof and a key actuation socket in registry with said keyhole, said lock actuation cylinder rotatable by a key having a polygonal cross section fit into said socket, said lock actuation cylinder fixed for rotation with said lock cam for locking said base plate to said cover; anda tumbler plate movable with respect to said lock actuation cylinder and interposed between said keyhole and said key actuation socket, and having a bore which is out of registry with said keyhole and movable into registry by a key pushed into said keyhole.