| 摘要 |
<p>A key-operated pin tumbler lock comprises a shell (20) in which is rotatably disposed a plug (21) that defines a keyway (23) and a plurality of bores (24). The bores communicate with the keyway (23) through the plug (21) and in a locked position of the lock communicate with corresponding bores formed in the shell (21). A plurality of spring-loaded pin stacks (25) are located within the bores (24) and are moveable within the bores (24) against the spring-loading (31) by a key (40) inserted in the keyway (23) into a position wherein the plug (21) can be rotated relative to the shell (20). A stop means (32) is provided in one (26) of the bores and is adapted to engage the pin stack (27) which is located therein such that a key pin (34) of the stack (27) is prevented from penetrating into the plug (21) to a level reached by key pins (29) of the other pin stacks (25). Such a lock is significantly less susceptible of being opened by a lock bumping technique than a conventional key- operated pin tumbler lock. Preferably, the plurality of spring-loaded pin stacks (25) each have a height randomly selected from a bitting range, and a second additional pin stack (53) is provided in the lock that has a height greater than the greatest height of said bitting range. A key adapted to lock and to unlock said key-operated pin tumbler lock is also provided.</p> |
