Positioning structure of the transmission device of a screw fastening apparatus

A positioning structure of the transmission device of a screw fastening device having a securing seat, a screwing rod, a mobile seat, a positioner, and a transmission device mounted within the mobile seat, characterized in that the transmission device includes a stopping circular block, gear body and a braking body, the stopping block has a center hole thereon for the insertion of the shaft of the braking body and one lateral circular face thereof has a slanting protruded block for the engagement with a plurality of recesses of the gear body, and between another lateral circular face and the inner face of the mobile seat, an elastic rim is provided, and the end face of the circular block is a guiding block having a screw hole for a rotating bolt to lock to, the circular block rotates together with the screw bolt so as to rotate the gear body and the gear body is H-shaped having two lateral sides provided with a plurality of teeth to move screws, and the center of the gear body has a hole for the insertion of the shaft of the braking body and one lateral side is provided with slanting holes arranged in a circle, the slanting holes is adapted for the protruded block on the braking block, the other lateral face of the gear body is provided with a plurality of engaging holes arranged in a circle, one side of the braking body has a square seat plate corresponding to the square plate, and one side of the seat plate is protruded with a shaft and the end head of the shaft is circular, on the seat plate a plurality of engaging blocks are provided and the engaging block is corresponding to the engaging hole of the gear block and the lateral side of the seat plate, corresponding to the center of the shaft is a slot for the urging of a spring, and the other end of the spring urges the square plate, and the shaft passes through the hole of the gear, the hole of the stopping block and the elastic rim then to the hole of the mobile seat, thereby when the mobile seat moves, the bolt is delivered to the arch-shaped path to drive the stopping block in clockwise direction, and the protruded block is moved away from the slanting hole until the block is corresponding to another slanting hole and the front end of the securing seat urges the shaft and the braking body moves by the spring and the engaging block and the engaging hole are dislocated, when the securing seat moves forward from the mobile seat, the slanting circular end head will not urge by the end face of the securing seat to protrude outside the hole of the mobile seat, and the rotating bolt moves forward with the mobile seat and restores at the arch-shaped slot and drive the stopping block to rotate counter clockwise, and the stopping block drives the gear body to rotate counter-clockwise and screws will be moved in sequence until the engaging hole of the gear body and the engaging block of the seat plates are in engagement, and the gear body is stopped at the engaging block so as to prevent the screw from shaking until the screw is firmly moved to the screw slot at the mobile seat and is fully stopped.