Chuck device

A chuck device in which a plurality of claws inserted into a hole provided at an end of a body are opened, closed and slid by the rotation of a rotary sleeve and a tool is clamped by means of the claws, wherein an annular ratchet wheel is provided on the body, an annular nut member to be engaged with the claws and to be rotated together with the rotary sleeve is fitted in the body inside of the rotary sleeve, a retainer spring member detachably retained with a tooth of the ratchet wheel is arranged outside of the ratchet wheel, the retainer spring member is composed of two spring members, one of the retainer spring members is adapted to function the retention effect with the ratchet wheel, other retainer spring member keeps a position of the retainer spring member by maintaining the position of the rotary sleeve , the retainer spring members are arranged to rotate around the ratchet wheel in accordance with the rotation of the nut member, the retainer spring members are mounted on the nut member by convex/concave engagement means, a retainer portion keeps a condition that the ratchet wheel and the retainer spring member are retained to each other and a condition that the engagement between the ratchet wheel and the retainer spring member is released, the retainer portion is disposed between the body and the rotary sleeve and defined by the retainer spring member and an inner surface of the rotary member, the body is made of light material selected from the group essentially consisting of aluminum and aluminum alloy, and a coating that is hard and has a low frictional coefficient as much as possible is applied to a surface of said body and an inner surface of said hole.