Patent ID: 7146885

Claim:
An adjustment mechanism mountable in a joining portion of a handle of a tool and a shank of multi-sided section thereof for releasably locking the shank in any one of a plurality of positions relative to the handle, comprising: a sleeve forwardly extended from the handle, the sleeve including a multi-sided bore of staged, a front flared end, an externally threaded section around the flared end, and an inner portion with reduced diameter, the bore of the sleeve being in communication with an internal bore of the handle; a resilient member having its rear end contacted a slope of the bore of the sleeve; a shell including two opposite slots formed on its outer surface and being in communication with its inside, and two bars provided in the slots, the shell having its rear end contacted a front end of the resilient member; and a nut threadedly secured to the externally threaded section of the sleeve, wherein the shank is inserted through the nut, the shell, the resilient member, and the bore of the sleeve to have its rear end slidably fastened in the bore of the handle with outer portions of the bars being in contact with internal faces of the flared end, and inner portions of the bars being in contact with faces of the shank, whereby pulling the shank forward will move the bars outward forward along the flared end to expand the resilient member for extending the shank; and stopping sliding the shank will lockingly engage the shank; pushing the shank rearward will move the bars inward rearward along the flared end to compress the resilient member for retracting the shank, and stopping sliding the shank will lockingly engage the shank; and loosening the nut will move the shell forward and expand the resilient member until the shank is free to slide with the bars disposed at a mouth of the flared end and disengaged from the shank.