Cylinder lock

A locking mechanism for use in a lock assembly including a lock body having an inner surface defining a bore having a longitudinal axis and a longitudinal slot extending along at least a portion of the inner surface, and a key plug defining a keyway extending longitudinally from one end and a plurality of longitudinally spaced pin bores extending from the outer surface of the key plug and opening into the keyway, the key plug rotatably disposed in the bore of the lock body, the locking mechanism comprising:

• a plurality of pins having a recess formed therein, each of the plurality of pins adapted to be disposed in one of the plurality of pin bores in the key plug for reciprocal and rotational movement about an axis;
• an elongated spring member for simultaneously engaging and biasing the plurality of pins toward the keyway, the spring member adapted to be disposed in a longitudinal slot defined in the outer surface of the key plug contiguous with the plurality of pin bores;
• a locking bar adapted to be disposed in the groove in the key plug for movement between a first position where the locking bar is adapted to be received in the slot in the lock body and a second position where at least a portion of the locking bar is received in the recesses in the plurality of pins, the locking bar prevented from moving to the second position unless the plurality of pins are in a predetermined position where the recesses are aligned for receiving the at least a portion of the locking bar;
• and
• means for biasing the locking bar to the first position,
• wherein upon insertion of a proper key in the keyway the plurality of pins are moved axially or rotated about their axes for aligning the recesses in the plurality of pins with the locking bar so the key can rotate the key plug and the locking bar cams against the slot in the lock body to move the projections on the locking bar into the recesses to allow rotation of the key plug.