High security removable core cylinder lock

A removable core cylinder lock, comprising:

• a lock core having a keyway, a plurality of pin tumbler bores aligned with the keyway and a fence recess adjacent the bores;
• a lock housing having a longitudinal cavity for slideably receiving the core therein, a locking recess formed in a wall of the cavity, and a transverse retaining surface;
• a tumbler pin disposed in each of the bores and biased toward the keyway;
• a transverse opening formed in each tumbler pin and adapted to be aligned with the fence recess when properly positioned by a key inserted in the keyway;
• an outwardly biased fence disposed in the fence recess having an outer locking surface engageable in the locking recess and at least one inward projection receivable in a tumbler opening;
• a normally outwardly biased retainer disposed in the fence recess having an outer member engageable with the retaining surface and at least one inward projection receivable in a tumbler opening;
• means for inwardly biasing the retainer;
• wherein the core is in a locked position with respect to the housing by interengagement between the fence and the locking recess;
• wherein the core is operable in an unlocked, unremovable mode by insertion of a proper operating key in the keyway to selectively position the pin tumblers for aligning each inward projection of the fence with a respective pin tumbler opening without alignment of each inward projection of the retainer with a respective pin tumbler opening, so that the fence is inwardly slideable for disengagement of the locking surface from the locking recess upon rotation of the core with respect to the housing and the outer member of the retainer is maintained in slideable engagement with the retaining surface to keep the core in the housing;
• wherein the core is operable in a removal mode by insertion of a proper removal key to position the pin tumblers for aligning each inward projection of the fence and of the retainer with a respective pin tumbler opening so that the fence and retainer are inwardly slideable upon rotation of the core with respect to the housing for disengaging the locking surface from the locking recess and the retainer from the retaining surface to allow removal of the core from the cavity.

A removable core cylinder lock, comprising:

• a lock core having a keyway, a plurality of pin tumbler bores aligned with the keyway, a longitudinal fence recess and a transverse retainer recess adjacent the bores;
• a lock housing having a longitudinal cavity for slideably receiving the core therein, a longitudinal locking recess formed in a wall of the cavity opposite the fence recess, and a transverse retaining endwall adjacent the retainer recess;
• a tumbler pin disposed in each of the bores and biased toward the keyway;
• a transverse opening formed in each tumbler pin and adapted to be aligned with the fence recess when properly positioned by a key inserted in the keyway;
• an outwardly biased fence disposed in the fence recess having an outer locking surface engageable in the locking recess and at least one inward projection receivable in a tumbler opening;
• a normally outwardly biased retainer disposed in the retainer recess having an inner arm carrying an inward projection receivable in a tumbler opening, an outer arm engageable with the housing endwall, a member rigidly connecting the inner and outer arms and a central channel;
• a finger formed on the fence and received in the retainer channel adjacent the outer arm and outwardly supporting the retainer;
• a spring between the finger and the inner arm inwardly biasing the retainer;
• wherein the core is in a locked position with respect to the housing by interengagement between the retainer and the housing endwall;
• wherein the core is operable in an unlocked, unremovable mode by insertion of a proper operating key in the keyway to selectively position the pin tumblers for aligning each inward projection of the fence with a respective pin tumbler opening without alignment of the inward projection of the retainer with a respective pin tumbler opening, so that the fence is inwardly slideable for disengagement of the locking surface from the locking recess upon rotation of the core with respect to the housing and the outer arm of the retainer is maintained in slideable engagement with the housing endwall to keep the core in the housing;
• wherein the core is operable in a removal mode by insertion of a proper removal key to position the pin tumblers for aligning each inward projection of the fence and of the retainer with a respective pin tumbler opening so that the fence and retainer are inwardly slideable upon rotation of the core with respect to the housing for disengaging the locking surface from the locking recess and the retainer from the housing endwall to allow removal of the core from the cavity.