EMPLOYEE WAS PREPARING TO REMOVE UPPER SEGMENT BOLTS ON D10 DOZER WHILE POSITIONING AN AIR TORQUE WRENCH SOCKET ONTO ONE OF THE BOLTS WITH HIS LT. HAND, THE TORQUE WRENCH TRIGGER INADVERTENTLY STRUCK THE SEGMENT CAUSING THE WRENCH TO TURN ON. FINGERS WERE PINCHED BETWEEN THE TORQUE WRENCH BRACE & THE MACHINE SPROKET.