Patent ID: 7185713

Claim:
An air-driven screwdriver for hole drilling, bolt tightening and thread tapping comprising: a pistol type body; a motor assembly; an inner gear assembly; a chuck; and a chamber which houses the motor section, the inner gear assembly and the chuck, wherein the motor section comprises a case for receiving a rotor, the rotor being encircled with a plurality of radiant blades, the motor section comprising at a front end, a securing sleeve, a bearing c ring and a square drive linked with the rotor, the motor section comprising, at the rear end, upper and lower turn tables including an air valve, a punch, a cap, a spring and an outer cap, wherein the chuck comprises a central passage with one end to link to a connecting shaft and the other end to receive a tool tip, wherein the inner gear assembly contains an inner threaded torque cylinder including two pairs of round gear disk and a start gear linked with a drive gear, at the front end of the torque cylinder a cam seat being located and formed in three set-in layers, a first layer, a second layer and a third layer, wherein on the second layer, several recesses are located to receive catching balls sealed by a ring, a torque spring and a torque adjusting ring to set up the torque required, wherein the cam seat has the connecting shaft linked to the chuck to complete the power chain.