Mechanical/electronic lock and key therefor

An electrically operated lock cylinder blocking arrangement, comprising:

• a lock cylinder installed into a lock unit having electronic access control components requiring power, and the cylinder having a rotatable plug attached to a movable rear piece that interacts with a latch or bolt of the lock unit when a key is inserted into a keyway of the plug and the plug is rotated,
• a retractable blocking element positioned in a recess of a cylinder shell of the lock cylinder for reciprocal movement toward and away from the cylinder plug, between a first, blocking position and a second, retracted position, the blocking element having a long dimension oriented generally parallel to the length of the plug, and the plug having a groove within which the blocking element engages when in said first, blocking position, with spring means urging the blocking member toward the first, blocking position,
• the cylinder including at least one slidable wafer within the cylinder, with an opening or recess in the wafer near one end, and a motor or solenoid having a moveable member with two positions, a first position extending into the opening of the wafer and preventing sliding movement of the wafer and a second position retracted from the wafer opening allowing sliding movement of the wafer, and including a wafer spring urging the slidable wafer toward an unblocking position to which the wafer is slidable when the movable member of the motor or solenoid is retracted, and the wafer having a second end which interacts with the retractable blocking element such that the retractable blocking element can only retract from said groove and from said first, blocking position when the wafer is in said unblocking position, and
• the wafer and the direction of its sliding movement being such that a premature twisting of a key in the cylinder plug, tending to cam the retractable blocking element outwardly from said groove, causing a force on the wafer, will not push the wafer against said moveable member of the motor or solenoid, thus not jamming the movable member.