US Patent 6891458 Electronic cam assembly

A lock may be constructed with a locking mechanism that uses either a cam assembly with a cylinder plug perforated by a centrally positioned keyway or a cylinder plug. The locking mechanism may be equipped with a dual armature solenoid. With the dual action solenoid constructed with a single wire coil, the distal ends of coaxially aligned armatures engage opposite axially aligned detents to maintain the lock in its locked state, while application of a potential difference across the coil draws both armatures away from their corresponding detents and toward the bore of the coil, thereby placing the lock into its unlocked state.