US Patent 7178811 Chuck capable of drawing in and pushing out collet

A chuck is composed of a collet sleeve, a sliding member, at least one linkage member, a collet, and a driving member. The collet sleeve includes an axial hole running therethrough and at least one opening in communication with the axial hole. The sliding member is slidably received in the axial hole of the collet sleeve. The linkage member is inserted through the opening of the collet sleeve and connected to the sliding member. The collet is inserted into the axial hole of the collet sleeve and connected to the sliding member. The driving member drives the linkage member and the sliding member to move for drawing in and pushing out the collet with respect to the collet sleeve.