Patent ID: 8262095

Claim:
An improved chuck having one end coupling with a fabrication machine through a holding member and the other end holding a fabrication tool, comprising: a coupling structure which has one end forming a first screwing portion and the other end coupling with at least a fastening member; a grip means which has one end forming a second screwing portion engageable with the first screwing portion and the other end having a plurality of spaced grip jaws to form a tool holding space, the grip means being elastic and inclined outwards; and a shank which has a through hole to hold the coupling structure and the grip means, the through hole having one end fastened to the holding member and an internal side to form compact holding of the grip means to allow an opening of the through hole to firmly hold the fabrication tool, the through hole being formed at an internal diameter gradually expanded from the center thereof towards the opening; wherein when the fastening member is coupled with a fixture to anchor the coupling structure, the shank is turnable to drive the grip means so that the first screwing portion and the second screwing portion are moved relative to each other, and the grip means is movable in the direction of the through hole such that the grip jaws are expanded or contracted to release or grip the fabrication tool.