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US 5,615,566 AGranted
Cylinder lock and key
OwnerGreg N. Brandtinventor
Life of this patent
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Abstract
An improved security cylinder lock and key for operating the cylinder lock are disclosed. The cylinder lock has conventional tumbler locking structure and a secondary locking bar that operates independently of the tumblers. The secondary locking bar prevents operation of the cylinder lock until a properly configured key is placed in the keyway of the cylinder lock.
Claims8
A cylinder lock comprising:
- an elongated lock shell having opposed axial front and rear ends and a hollow plug-receiving chamber extending therebetween, said rear end including a notch formed therein;
- an elongated cylinder plug rotatably received within said plug-receiving chamber, said plug including
- opposed axial front and rear ends and a hollow keyway extending therebetween for receiving a key blade, and
- a hollow slot radially spaced from and extending parallel to said keyway, said slot having an opening adjacent said plug rear end, said opening being in alignment with said lock shell notch when said cylinder plug has not been rotated within said plug-receiving chamber, said slot further having a side opening in communication with said keyway;
- and
- an elongated locking bar reciprocally mounted in said hollow slot, said locking bar including
- a first end extending from said slot opening and normally received within said lock shell notch for preventing rotation of said cylinder plug within said plug-receiving chamber, and
- a second end axially opposed from said first end and including a protruding portion protruding into a portion of said keyway, wherein the insertion of a key having a protruding surface on one side thereof in said keyway enrages said protruding portion of said locking bar and shifts said locking bar towards said cylinder plug rear end so that said first end of said locking bar is shifted out of said notch for permitting rotation of said cylinder plug within said plug-receiving chamber.
5 more elements
A locking apparatus comprising:
- a cylinder lock including a keyway, a set of tumblers, an elongated hollow slot radially spaced from and extending parallel to the keyway and a secondary locking bar reciprocally mounted in the slot;
- and
- a key for operating said cylinder lock, said key including a bow, and an elongated key blade, said key blade including
- a proximal end attached to one end of said bow,
- a distal end,
- a pair of opposed edges extending between said proximal and distal ends, and
- a pair of side margins interconnecting said edges,
- one of said side margins including a protruding surface extending therefrom for engaging said locking bar of said cylinder lock and shifting said locking bar in said slot when said key is inserted in said keyway of said cylinder lock.
5 more elements
Dependencies are inferred from the claim text.