Patent ID: 8869660

Claim:
A clamping structure for a wrench, wherein the clamping structure is located in an offset ring of the wrench, and comprises: a plurality of grooves disposed equidistantly in the Whet ring; and an inner surface located between two grooves, the inner surface comprising, in an order from the grooves to a center of the inner surface: two inclined planes, wherein an angle between a hypothesized extension line of one of the inclined planes and a hypothesized central line of one of the grooves is 40 degrees-50 degrees; two convex arcs connected to the inclined planes, wherein the two convex arcs has two top points respectively, and a distance between the two top points is one half of a length of the inner surface; two concave arcs connected to the inclined planes; and a middle salient connecting one of the concave arcs to the other of the concave arcs.