Patent ID: 8863624

Claim:
A torque wrench with functional lock, comprising: a hollow main shaft, provided with a first and a second end, while the outer periphery of the second end is axially provided with plural locating grooves; a tool member, inserted into the first end of the hollow main shaft; an adjustable grip, provided with an adjustment screw member screwed to the second end of the hollow main shaft; a torque-adjustment elastic member, disposed inside the hollow main shaft and stopped against one end of the adjustment screw member; a clutch device, disposed between the torque-adjustment elastic member and the tool member, and pushable by the torque-adjustment elastic member between an engaged position and a disengaged position; a functional lock, disposed on the outer periphery of the second end of the hollow main shaft, axially moves between a locked position and an unlocked position along the hollow main shaft, and further comprising a metal locking ring mounted in between the second end of the hollow main shaft and the adjustable grip, with a containing groove disposed on one end of an inner side wall of the locking ring and a pushing face axially extending on one side of the containing groove; a compression spring, disposed between the locking ring and the adjustable grip and permanently pushing the locking ring; an annular groove, disposed on the other end of the inner wall of the locking ring; a C-clasp made of metal, disposed on one end of the adjustable grip for being optionally coupled with the annular groove; at least a through hole, disposed on the periphery of the adjustable grip; and at least a metal positioning ball, disposed in the through hole, wherein when the functional lock is in the locked position, the positioning ball is pushed by the pushing face to resist against the locating groove for limiting the rotation of the adjustable grip against the hollow main shaft, and when the functional lock is in the unlocked position, the C-clasp is coupled with the annular groove, enabling the positioning ball to move between the containing groove and the locating groove, whereby the adjustable grip is allowed to rotate against the hollow main shaft, while a percussion sound is produced when the locking ring is switched between the locked position and the unlocked position.