Abstract: A torque augmentor operatively associated with the cylinder assembly and the plug assembly of a pin tumbler lock cylinder increases the threshold torque required to rotate the plug assembly in the cylinder assembly, thereby hampering an attacker's “feel” for the relationship of the cylinder pins to the shear line, and of the plug assembly to the cylinder. One embodiment of the pick-resistant lock cylinder includes a spring-biased ball normally disposed across the shear line. Another embodiment has a cam normally biased into engagement with a cam follower, the cam being disposed on one of the cylinder assembly and the plug assembly, and the cam follower being disposed on the other. Another embodiment includes an hourglass-shaped false shear line creator operatively associated with the cylinder assembly and plug assembly. The coaction of the torque augmentor and false shear line creator of the lock cylinder of the present invention also hampers an attack by bumping.

Abstract: A rekeyable lock cylinder includes a cylinder body and a plug assembly, which includes key followers normally biased for linear movement into a home position. Locking bar interfaces in the plug assembly are rotatably connected to respective key followers for simultaneous linear movement with the key followers, and are movable from a non-rotatable to a rotatable position within the plug assembly. Each interface defines a plurality of angularly-spaced unlocking cavities alignable with a locking bar operatively associated with the cylinder body and plug assembly. When the user causes the interface to move into the rotatable position, it can be rotated to re-align any or all of the unlocking cavities with the locking bar. Inasmuch as each unlocking cavity is also associated with a particular elevation of the interface's respective key follower, re-aligning one or more such cavities resets the respective elevations of the key followers so that they can accept only a different valid key.

Abstract: A torque augmentor operatively associated with the cylinder assembly and the plug assembly of a pin tumbler lock cylinder increases the threshold torque required to rotate the plug assembly in the cylinder assembly, thereby hampering an attacker's “feel” for the relationship of the cylinder pins to the shear line, and of the plug assembly to the cylinder. One embodiment of the pick-resistant lock cylinder includes a spring-biased ball normally disposed across the shear line. Another embodiment has a cam normally biased into engagement with a cam follower, the cam being disposed on one of the cylinder assembly and the plug assembly, and the cam follower being disposed on the other. Another embodiment includes an hourglass-shaped false shear line creator operatively associated with the cylinder assembly and plug assembly. The coaction of the torque augmentor and false shear line creator of the lock cylinder of the present invention also hampers an attack by bumping.

Abstract: A rekeyable lock cylinder includes a cylinder body and a plug assembly, which includes key followers normally biased for linear movement into a home position. Locking bar interfaces in the plug assembly are rotatably connected to respective key followers for simultaneous linear movement with the key followers, and are movable from a non-rotatable to a rotatable position within the plug assembly. Each interface defines a plurality of angularly-spaced unlocking cavities alignable with a locking bar operatively associated with the cylinder body and plug assembly. When the user causes the interface to move into the rotatable position, it can be rotated to re-align any or all of the unlocking cavities with the locking bar. Inasmuch as each unlocking cavity is also associated with a particular elevation of the interface's respective key follower, re-aligning one or more such cavities resets the respective elevations of the key followers so that they can accept only a different valid key.