A key for use in a cylinder lock with a rotatable key plug having an elongated key blade with a relatively wide lower portion and a relatively narrow upper portion. A step-like transition region between the wider lower portion and the narrow upper portion. The key blade includes a longitudinal profile groove located adjacent to the step-like transition region that extends along at least a portion of the length of the blade. An inner wall of groove is substantially parallel to a side surface of the lower portion of the key blade. The longitudinal profile groove includes an undercut portion adjacent to and inside a ridge portion of the key blade. The outside of ridge portion forms a part of the side surface of the blade in the relatively wide lower portion up to the step-like transition region and the inside of ridge portion facing inner wall of the groove.

Some embodiments include a lock cylinder comprising: a plug assembly having a front portion and a back portion; a housing shell within which the plug assembly is rotatably disposed, wherein the housing shell includes a notch; wherein the back portion of the plug assembly comprises: a locking pin that is movably disposed, and wherein the locking pin is configured to prevent a rotation of the plug assembly when the locking pin is engaged in the notch and prevented from retracting by a multi-stable mechanism; and the multi-stable mechanism having at least two stable configurations corresponding to respectively to a locked state and an unlocked state, wherein the multi-stable mechanism can maintain the stable configurations without consuming energy; wherein, at a first stable configuration, the multi-stable mechanism prevents the locking pin from retracting, and, at a second stable configuration, the multi-stable mechanism enables the locking pin to retract.

An exemplary lock cylinder includes a shell, a plug positioned in the shell, and a locking assembly. The locking assembly is configured to prevent rotation of the plug when no key is inserted, and to permit rotation of the plug upon insertion of any of a plurality of keys having different bitting profiles. The locking assembly may further be configured to prevent key extraction when the plug is in a rotated position.

An exemplary lock cylinder includes a shell, a plug positioned in the shell, and a locking assembly. The locking assembly is configured to prevent rotation of the plug when no key is inserted, and to permit rotation of the plug upon insertion of any of a plurality of keys having different bitting profiles. The locking assembly may further be configured to prevent key extraction when the plug is in a rotated position.

A rekeyable lock cylinder includes a plug body with a keyway opening along a longitudinal axis and a multiple of channels transverse to the axis. A rekeying feature located adjacent to the keyway opening.

A key for use in a cylinder lock with a rotatable key plug having an elongated key blade with a relatively wide lower portion and a relatively narrow upper portion. A step-like transition region between the wider lower portion and the narrow upper portion. The key blade includes a longitudinal profile groove located adjacent to the step-like transition region that extends along at least a portion of the length of the blade. An inner wall of groove is substantially parallel to a side surface of the lower portion of the key blade. The longitudinal profile groove includes an undercut portion adjacent to and inside a ridge portion of the key blade. The outside of ridge portion forms apart of the side surface of the blade in the relatively wide lower portion up to the step-like transition region and the inside of ridge portion facing inner wall of the groove.

Some embodiments include a lock cylinder comprising: a plug assembly having a front portion and a back portion; a housing shell within which the plug assembly is rotatably disposed, wherein the housing shell includes a notch; wherein the back portion of the plug assembly comprises: a locking pin that is movably disposed, and wherein the locking pin is configured to prevent a rotation of the plug assembly when the locking pin is engaged in the notch and prevented from retracting by a multi-stable mechanism; and the multi-stable mechanism having at least two stable configurations corresponding to respectively to a locked state and an unlocked state, wherein the multi-stable mechanism can maintain the stable configurations without consuming energy; wherein, at a first stable configuration, the multi-stable mechanism prevents the locking pin from retracting, and, at a second stable configuration, the multi-stable mechanism enables the locking pin to retract.

A key for use in a cylinder lock with a rotatable key plug having a profiled keyway. The key comprises an elongated, substantially flay key blade (120; 120) having a longitudinal profile groove (122; 122) extending along at least a portion of the length of the key blade. The groove has an undercut portion (129) adjacent to a ridge portion (128, 128), the outside of which forms part of a side surface (123; 123) of the key blade. The undercut portion (129; 129) of the groove is expanded, at its innermost part adjacent to and inside said ridge portion, into a longitudinally extending pocket (135; 135).

Some embodiments include a lock cylinder comprising: a plug assembly having a front portion and a back portion; a housing shell within which the plug assembly is rotatably disposed, wherein the housing shell includes a notch; wherein the back portion of the plug assembly comprises: a locking pin that is movably disposed, and wherein the locking pin is configured to prevent a rotation of the plug assembly when the locking pin is engaged in the notch and prevented from retracting by a multi-stable mechanism; and the multi-stable mechanism having at least two stable configurations corresponding to respectively to a locked state and an unlocked state, wherein the multi-stable mechanism can maintain the stable configurations without consuming energy; wherein, at a first stable configuration, the multi-stable mechanism prevents the locking pin from retracting, and, at a second stable configuration, the multi-stable mechanism enables the locking pin to retract.