Patent ID: 8366339
Filing Date: 2013-02-05
Classification: F16C,F16D,Y10T

Abstract:
1. A two-section tool joint comprising: a support member including a first end and an opposing second end, wherein a polygonal ball knob having a plurality of sides is disposed adjacent said first end; an acting head including a receiving chamber disposed in an upper end thereof, wherein said polygonal ball knob is received in said receiving chamber, and wherein a plurality of raised rims are arranged circumferentially on an inner side wall of the receiving chamber, and wherein the number of said plurality of raised rim corresponds to the number of sides of said polygonal ball knob; and a limiting structure seated within the inner side wall of the receiving chamber adjacent the upper end of the acting head, wherein said limiting structure retains the ball knob of the support member within the receiving chamber in such a manner that the support member is moveable between a first position, in which the support member is fixedly engaged with the acting head, and a second position, in which the support member can swing relative to the acting head by pivoting about the ball knob; wherein the raised rims are longitudinally defined on said inner side wall of the receiving chamber, and each raised rim comprises a convex arc contacting surface engaging with a corresponding side of said ball knob so that the support member and the acting head are rotationally locked; wherein any two adjacent convex arc contacting surfaces are separated and connected by a concave arc surface, whereby the concave arc surfaces are formed longitudinally in the inner side wall of the receiving chamber; wherein each convex arc contacting surface defines a center point and a radius of curvature, such that the plurality of convex arc contacting surfaces define a plurality of circles arranged circumferentially about the acting head, each circle having the same center point and radius as a respective one of the plurality of convex arc contacting surfaces, and wherein in a lateral cross-section view, no two adjacent circles intersect.