Abstract

A drill chuck is disclosed with a pair of jaws and a pair of jaw guiding base plates for centering and holding a drill bit. The chuck comprises a cylindrical housing for the pair of base plates in which the jaws are functionally located. Internal channels and platforms of the above plates guidedly control the movement of the pair of jaws and support a manual adjusting mechanism. The configuration of each of the jaws is such that two rows of triangular spaced apart teeth furnish an adjustable drill receiving opening, or corridor, which is constantly a square for the full range of opening adjustments. Shoulder extensions of the jaws are guidedly located in "V" shaped channels of the base plates. Dowel pins couple an adjusting mechanism to the jaws for guided movement. The adjusting mechanism includes a wedge-shaped body coupled to the dowel pins and a shaft having a left-hand threaded portion threadedly secured to the wedge body and a right-hand threaded portion threadedly retaining a jam nut and an adjusting knob. The nut is frictionally secured within cavities of the base plates. Rotation of the adjusting knob causes the movement of the left and right-hand portions of the shaft through the wedge body and the jam nut for controlling the opening and closing of the jaw opening, or corridor, for centering and holding a drill.