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US 3,985,010 AGranted
Method and apparatus for decoding twisting tumbler lock and twisting tumbler lock resistant thereto
AssigneeLock Technology, Inc.
InventorRobert A. Idoni
Life of this patent
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AssigneeLock Technology, Inc.
InventorRobert A. Idoni
Estimating the term…
Method and apparatus for decoding twisting tumbler lock of the type wherein side bar is sole locking element and normally bridges shear plane unless radial apertures in twisting tumblers are all in vertical and horizontal register with complementary side bar protrusions. Decoding apparatus comprises three devices each with a blade insertable in keyway and having upwardly and rearwardly sloping front surface angulated at one of three angles to which tumblers must be twisted for horizontal registration of apertures. Each blade has indicia for indicating that front surface is at particular tumbler and further has indicia for determining amount of elevation of tumbler resulting from camming action between chisel shaped tumbler bottom and blade front surface when blade is advanced from initial engagement with tumbler to elevate tumbler. Method includes step of torquing blade during advancement to bias side bar toward tumblers and thus force protrusion into associated tumbler aperture when aperture registers with protrusion. This movement causes small but detectable resistance to further advancement and, thus, yields positive indication of registration. As angle of front surface is known and required tumbler elevation is known, tumbler is decoded. By repeating process with all tumblers, lock is decoded.
In a method of decoding a twisting tumbler lock of the type including a cylinder shell, a key plug rotatably mounted in said cylinder shell and having a longitudinally extending keyway therein, a plurality of transversely extending longitudinally spaced tumblers slidably and rotatably mounted in said key plug, each of said tumblers having a chisel shaped bottom disposed in said keyway and a radially extending aperture in the periphery thereof located at one of a predetermined number of different angles to the axis of said chisel shaped bottom and at one of a predetermined number of different distances from said bottom, and a longitudinally extending transversely movable side bar having a plurality of protrusions, one for each tumbler, movable into said tumbler apertures, means for biasing said side bar into bridging relation with the shear plane of said lock, said side bar being permitted to move out of said bridging relation when all of said tumbler apertures are in horizontal and vertical register with said side bar protrusions, said apertures being horizontally registered with their associated protrusions when the chisel shaped bottom of said tumbler engages a key bit surface angulated at a preselected one of said predetermined angles and being vertically registered when said tumbler bottoms engage bits of predetermined depths of cut, said method comprising the steps of:
Apparatus for decoding a twisting tumbler lock of the type including a cylinder shell, a key plug rotatably mounted in said cylinder shell and having a longitudinally extending keyway therein, a plurality of transversely extending longitudinally spaced tumblers slidably and rotatably mounted in said key plug, each of said tumblers having a chisel shaped bottom disposed in said keyway and a radially extending aperture in the periphery thereof located at one of a predetermined number of difangles to the axis of said chisel shaped bottom and at one of a predetermined number of different distances from said bottom, and a longitudinally extending transversely movable side bar having a plurality of protrusions, one for each tumbler, movable into said tumbler apertures, means for biasing said side bar into bridging relation with the shear plane of said lock, said side bar being permitted to move out of said bridging relation when all of said tumbler apertures are in horizontal and vertical register with said side bar protrusions, said apertures being horizontally registered with their associated protrusions when the chisel shaped bottom of said tumbler engages a key bit surface angulated at a preselected one of said predetermined angles and being vertically registered when said tumbler bottoms engage bits of predetermined depths of cut, said apparatus comprising a number of devices corresponding to the number of different angles said radial apertures are disposed to said chisel shaped bottoms, each of said devices including:
Dependencies are inferred from the claim text.