Impression-resistant lock
OwnerRichard Hucknallinventor
Life of this patent
Estimating the term…
Abstract
A cylinder lock wherein both cylinder and plug are radially bored to receive pin-pairs of specific design. A pin freeze element is positioned for movement within the plug in a direction substantially orthogonal to the axis of the plug bores. The interface between the pin freeze element and the pins includes incremental notches of matching configuration such that when the plug is turned, the pin freeze element engages the pins locking them from reciprocal movement. The mating surfaces of the pin freeze element and pins must be in registration for the plug to turn at all and they must be in perfect registration and properly aligned for the lock to open.
Claims15
A cylinder lock comprising a cylinder and a key plug mounted for rotation therein, a key slot in said plug and a radial plug bore extending from said key slot to the periphery of said plug, a radial cylinder bore extending within said cylinder and positioned for axial alignment with said plug bore in the locked state of said cylinder lock, driver and tumbler pins mounted for reciprocal movement within said bores, a pin freeze element mounted within said plug for reciprocating motion along an axis substantially orthogonal to and intersecting the axis of said plug bore, the adjacent surfaces of said tumbler pin and said pin freeze element being adapted to engage and prevenbt reciprocation of said tumbler pin, means biasing said pin freeze element out of engagement with said tumbler pin, and means for selectively engaging said pin freeze element and said tumbler pin when said key plug is rotated.
A cylinder lock comprising a cylinder and a key plug mounted for rotation therein, a key slot in said plug and a radial plug bore extending from said key slot to the periphery of said plug, a radial cylinder bore extending within said cylinder and positioned for axial alignment with said plug bore in the locked state of said cylinder lock, driver and tumbler pins mounted for reciprocal movement within said bores, a pin freeze element mounted within said plug for reciprocating motion along an axis substantially orthogonal to and intersecting the axis of said plug bore, means for selectively engaging said pin freeze element and said tumbler pin when said key plug is rotated, the lower portion of said tumbler pin and the proximate portion of said pin freeze element being provided with cooperating grooves, said pin freeze element being biased away from said tumbler pin and projecting into a camming slot in said cylinder, the grooves in said tumbler pin and said pin freeze element being adapted to engage whenever said key plug is rotated, the respective lengths of said driver and tumbler pins being selected to position the parting line therebetween along the shear line between the key plug and cylinder when a proper key is inserted in said key slot.
Dependencies are inferred from the claim text.