Patent ID: 8336346

Claim:
A lock comprising: a lock body; a key; a key mass rigidly coupled to the lock body, the key mass including a first key mass bore, a keyway in communication with the first key mass bore and having a hole into which the key is insertable, and at least first and second key mass segments arranged one behind the other along the keyway such that a key inserted in the hole of the keyway passes sequentially into the first and second key mass segments; a spring mass movable relative to the key mass, the spring mass including a first spring mass bore; a stopper coupled to the spring mass and movable thereby between a locked position and an unlocked position of the lock; a first key mass pin mounted for reciprocation in the first key mass bore; and a first spring mass pin mounted for reciprocation in the first spring mass bore, wherein the keyway is configured to receive the key first through the first key mass segment and then into the second key mass segment, the received key being operable to motivate the first key mass pin between first and second positions corresponding respectively to the locked and unlocked positions of the lock, at least one of the first spring mass pin or first key mass pin interfering with the relative motion in the first position and not interfering with the relative motion in the second position, and wherein the first and second key mass segments are either unattached to one another or attached to one another sufficiently weakly such that a force applied to the first key mass segment capable of breaking one or more key mass bins or spring mass pins is not transferred to the second key mass segment.