Lock assembly for a personal computer system enclosure

An electronic device and lock assembly comprising:

• a cover containing said device, said cover having an opening into which a lock is held in a normal position by a fracture ring;
• said opening in said cover having a recess for receiving a positioning portion of said fracture ring;
• said positioning portion of said fracture ring being attached to a lock holding portion of said fracture ring by a reduced cross section, said reduced cross section providing a breaking portion which breaks when excessive torque is applied to said lock, said positioning portion having a plurality of lobes, each of said lobes extending radially from an outer perimeter of said fracture ring and each lobe having said breaking portion;
• said opening in said cover having a rebated area which is concentric with said opening and allows said fracture ring and said lock to move to a position in said opening when said fracture ring has been broken so as to make it apparent to an observer that said breaking portion has been broken.

A lockable computer comprising:

• an opening in said computer for receiving a lock housing, said lock housing having a cylindrical opening;
• a lock cylinder rotatable in said cylindrical opening of said housing, said lock cylinder having locking elements engaging said cylinder and said housing to hold said cylinder from rotation in said housing and to allow rotation in said housing only when a proper key is inserted into said cylinder;
• a frangible ring having a computer engaging part and a housing engaging part to hold said housing in a substantially central position in said opening in said computer;
• said frangible ring having a weakened computer engaging part which breaks when excessive torque is applied to an improper key in said cylinder allowing said housing to rotate with said cylinder to unlock said computer without said proper key, said computer engaging part having a plurality of lobes, each lobe having a reduced cross section designed to break when excessive torque is applied to said improper key;
• said opening in said computer having a rebated area which allows said frangible ring and said lock to move to a position in said opening when said frangible ring has been broken so as to make it apparent to an observer that said computer engaging part has been broken;
• said opening in said computer having a plurality of recesses, at least three of said lobes being seated in three of said recesses to hold said frangible ring out away from said rebated area so as to allow said lock to tip out of axial alignment providing a visual indication that said lock has been forced.