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US 4,535,546 AGranted
Locksmith tool apparatus for determining length of locking elements in locks
AssigneeNone recorded
InventorRodney D. Smith
Life of this patent
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AssigneeNone recorded
InventorRodney D. Smith
Estimating the term…
Locksmith tool apparatus determines the length of a locking element in a lock by engaging a locking element inside a lock and by moving the element to compress a compression spring to a known minimum length and by measuring the distance moved. By subtracting the distance the element is moved from known dimensions, the length of the locking element is determined.
Locksmith tool apparatus usable with a lock having a key way, a tumbler pin, a driver pin, and a compression spring biasing the driver pin and the tumbler pin, comprising, in combination:
Locksmith tool apparatus usable in a lock having a plurality of tumbler pins, driver pins, compression springs, and a key way communicating with the tumbler pins, and each compression spring biases a driver pin and a tumbler pin against the key way, comprising, in combination:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Skeleton keys; Devices for picking locks; Other devices for similar purposes ; Means to open locks not otherwise provided for, e.g. lock pullers:…
Measuring instruments characterised by the use of mechanical techniques: plug gauges for internal dimensions with engaging surfaces which are at a…
Measuring arrangements characterised by the use of mechanical techniques: for measuring length, width or thickness
Keys: picking
Term ended 27 Feb 2004 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
This invention relates to locksmith apparatus and, more particularly, to locksmith apparatus for determining the length of lock pins for expediting the cutting of keys when a key to be duplicated is not available.
2. Description of the Prior Art
FIG. 1 is a view in partial section of a lock with the apparatus of the present invention shown in fragmentary view, being inserted into the lock.
FIG. 2 is a view in partial section of the apparatus of FIG. 1, taken generally along line 2--2 of FIG. 1.
FIG. 3 is a side view, with portions in partial section, of the apparatus of the present invention.
FIG. 1 is a side view in partial section through a cylinder lock 8. The cylinder lock 8 includes a housing 10. In the lower part of the housing 10 is a cylindrical bore 12. Within the bore 12 is a rotating lock cylinder or plug 60. The lock cylinder or plug 60 includes a key way 62. A portion of a locksmith tool 100 of the present invention is shown extending partially into the key way 62.
FIG. 2 is a view in partial section of the lock housing 10 and the rotating lock cylinder or plug 60 taken generally along line 2--2 of FIG. 1. FIG. 3 is a side view, with a portion in partial section, of the locksmith tool apparatus 100 of the present invention. FIG. 4 is a view in partial section of a portion of the lock housing 10 and the rotating lock cylinder or plug 60, with a portion of the locksmith tool apparatus 100 extending into the key way 62, and illustrating the operation of the tool 100. FIG. 5 is an enlarged fragmentary view of a portion of the tool 100. For the following discussion, reference will be made to FIGS. 1, 2, 3, 4, and 5.
The lock housing 10 of the lock 8 includes five pin cylinders. The pin cylinders are aligned and are spaced apart substantially equally in the housing 10 and the rotating lock cylinder or plug 60. The cylinders include a first cylinder 14, a second cylinder 16, a third cylinder 18, a fourth cylinder 20, and a fifth cylinder 22. Tumbler pin locks typically have five or six or more pin cylinders, with a pair of pins being disposed in each of the pin cylinders. The lock 8 illustrated and discussed herein is shown having five cylinders and accordingly five upper or driver pins and five lower or tumbler pins.