Patent ID: 7487698

Claim:
A fastening member fastening apparatus in which a fastening member is positioned with respect to a fastened member so as to fasten the fastening member to the fastened member, comprising: a rotary axle body being rotatable through a drive source; a forwardly and backwardly movable socket being connected with a tip end of said rotary axle body to fit the fastening member thereon; and a guide mechanism having a plurality of claw members which are opened and closed in accordance with the forward and backward movement of said socket, wherein said fastening member and said socket are completely encompassed by said guide mechanism when said guide mechanism is closed, and wherein a tip end of said closed guide mechanism is inserted into a hole of the fastened member so as to position and fasten the fastening member fitted on said socket with respect to the fastened member, wherein said rotary axle body is provided with an air cylinder which comprises: a cylinder formed with a first hollow chamber and a second hollow chamber, a first piston connected with rear ends of said claw members and arranged to be slidable within said first hollow chamber, and a second piston arranged to be slidable within said second hollow chamber which is in communication with said first hollow chamber through a through bore when said first piston is positioned in the rearward of said first hollow chamber, wherein the forward and backward movement of said socket is carried out by the operation of the second piston, and wherein the opening and closing movement of said guide mechanism is carried out by the operation of the first piston.