Electromechanical cylinder lock

Abstract

An electromechanical cylinder lock includes an outer lock shell and a rotatable lock barrel located therein which is controlled by dual locking features. A side bar or fence selectively blocks and permits rotation of the barrel with respect to the shell in response to insertion of a key into a keyway in the barrel. A slider bar is movable between a blocking position in which the side bar is prevented from permitting rotation of the barrel, and an unblocking position in which the side bar permits rotation of the barrel. Alternately, a blocking mechanism is provided to block motion of tumbler pins in the cylinder lock. A shape memory alloy actuator, such as a wire made of nitinol, disposed in the barrel is activated by an electric current in response to determination by an electronic control device whether an attempt to open the lock is authorized. Thermal interlock protection from external heating of the lock is also provided.

1 . An electromechanical lock cylinder, comprising:
 an outer shell having a bore formed therein and a cavity extending from the bore into the shell;   a barrel disposed within the bore in the shell and being rotatable relative thereto;   a side bar cooperating between the shell and the barrel for selectively permitting and blocking rotation of the barrel with respect to the shell, the side bar having a first portion engaging the barrel and a second portion removably received in the cavity in the shell, the side bar being movable relative to the barrel and the shell;   a blocking mechanism, located in said barrel, positionable in a blocking position in contact with the side bar, which position blocks retraction of the side bar from the cavity in the shell, and thereby prevents rotation of said barrel, and also positionable in an unblocking position relative to the side bar, which permits the side bar to be retracted from the cavity in the shell to allow the barrel to be rotated with respect to the shell;   an electrically activated drive mechanism cooperating with the blocking mechanism to selectively move the blocking mechanism from the blocking position to the unblocking position in which the side bar moves out of the cavity upon rotation of the barrel; and   control means for activating the electrically activated drive mechanism in response to an authorized attempt to operate the lock cylinder.