Improvements to key-operated pin tumbler locks
AssigneesUAP Limited, Martin Pink
InventorMartin Pink
Life of this patent
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Abstract
A key-operated pin tumbler lock has a shell in which is rotatably disposed a plug that defines a keyway and a plurality of bores. The bores communicate with the keyway through the plug and in a locked position of the lock communicate with corresponding bores formed in the shell. A plurality of spring-loaded pin stacks are located within the bores and are moveable within the bores against the spring-loading by a key inserted in the keyway into a position wherein the plug can be rotated relative to the shell. A stop means is provided in one of the bores and is adapted to engage the pin stack which is located therein such that a key pin of the stack is prevented from penetrating into the plug to a level reached by key pins of the other pin stacks.
Claims18
A key-operated pin tumbler lock comprising
- a shell;
- a plug rotatably disposed relative to the shell and defining a keyway and a plurality of bores that communicate with the keyway through the plug and that, in a locked position of the lock, communicate with corresponding bores formed in the shell;
- a plurality of spring-loaded pin stacks that are located within all bar one of the bores and that are moveable within the bores against the spring-loading by a key inserted in the keyway into a position wherein the plug can be rotated relative to the shell;
- a first additional pin stack that is located in said one bore;
- and
- a stop means provided in said one bore and adapted to engage the additional pin stack which is located therein such that a key pin of the stack is prevented from penetrating into the plug to a level reached by key pins of the other pin stacks.
A key adapted to lock and to unlock a key-operated pin tumbler lock comprising a blade defining a plurality of notches that each have a depth randomly selected from a bitting range, and wherein the blade comprises an unnotched portion at a position that would otherwise be notched as one of said plurality of notches forming part of said bitting range.
Dependencies are inferred from the claim text.