US Patent 7003993 Electrified cylindrical lock

An electrified cylindrical lock having a reversible solenoid that can be easily changed over between fail safe and fail secure. The solenoid includes a coil and an armature that may be assembled for an active push or an active pull of a latch member. The latch member locks or unlocks the lock. The coil has a front end and a rear end. The front coil end always faces toward the latch member and the rear end always faces away from the latch member. The armature includes a magnetic slug. The slug is disposed at the rear coil end for the active push mode or disposed at the front coil end for the active pull mode.