LOCKING CYLINDER

The invention relates to a locking cylinder comprising a cylinder core that is rotatably mounted in the locking cylinder housing, core and housing pins, which can be displaced by a mechanically coded key into a position of alignment on the separation plane of locking cylinder housing and cylinder core, thus permitting the rotation of the cylinder core, in addition to an electric/electronic blocking device, which is located in the locking cylinder housing and can be controlled by an electronic coding of the key. The blocking device has an actuating element (15) that can be displaced by the rotation of the cylinder core in the locking cylinder housing. Said element co-operates with a spring element (14), which in turn is connected to a blocking element (13). To achieve the blocking position, said blocking element can be pressed into a recess on the inner periphery of the locking cylinder housing by the spring force, thus overlapping the separation plane of locking cylinder housing and cylinder core. In this blocking position, the blocking element (13) is prevented from moving out of the blocking position by an adjusting element (9) that forms part of the electric/electronic blocking device.