Patent ID: 7685854

Claim:
An axial spring balancing pin tumbler lock comprising: a shell having a through hole, a main bore defined on the rear end and a plurality of first pin bores defined annularly and evenly on the bottom surface of the main bore; a plug having a through aperture and a key bore coaxially defined on the front end, whereas a plurality of third pin bores being defined on the front end with same depth of the key bore and arranged such that each one of the third pin bores extends coaxially with one of corresponding first pin bores in the shell; whereas a plurality of second pin bores being defined annularly and evenly on the rear end and arranged such that each one of the second pin bores is radially and inwardly eccentric to its corresponding third pin bore; whereas each one of the second pin bores radially and axially overlapping the key bore and one of the corresponding third pin bores simultaneously; whereas the plug being disposed into the main bore of the shell; a spindle having a short axial groove defined on the front end and being fixedly engaged with the through aperture in the plug; a plurality of first coiled compression springs and first pins being disposed into the first pin bores in the shell; a plurality of second pins and second coiled compression springs being disposed into the second pin bores in the plug; a plurality of third pins being disposed into the third pin bores in the plug.