Patent ID: 7383975

Claim:
A friction stir welding tool comprising; (1) an integral pin and shoulder, (a) a pin portion designed that plunges into at least one workpiece to perform a friction stir welding operation on the at least one workpiece, (b) a shoulder portion including a working surface designed that engages at least one surface of the at least one workpiece, wherein (i) the pin portion includes a proximal end of the pin portion being contiguous with the working surface of the shoulder portion, (ii) a distal end opposite the proximal end, and (iii) a tension member engagement feature in proximity of the distal end; (2) a tool body defining a cavity therein, the cavity for receiving at least a portion of the shoulder portion of the integral pin and shoulder, the tool body further including a shank for engagement with a friction stir welding machine; (3) a tension member having (i) a distal end with an engagement feature complimentary to the tension member engagement feature of the pin portion and (ii) a proximal end with an engagement feature, wherein, the proximal end extends out of the tool body when the tension member is disposed within the integral pin-shoulder and the distal end engagement feature of the tension member is engaged with the tension member engagement feature of the pin portion; and (4) an adjustable tension member engagement device to adjustably engage the proximal end of the tension member to impose a predetermined inward axial force upon the tension member engagement feature of the pin portion and the tool body, thereby placing the pin portion in substantial compression between the distal end and the proximal end of the pin portion.