Diamond cutter rock bit with penetration limiting

Abstract From the Canadian patent

A rock bit for recovering core samples is described along with variations for drilling oil wells or the like. In each of these embodiments a plurality of diamond cutters are mounted on the bit body for cutting rock by a shearing action. Each diamond cutter is in the form of a thin diamond plate bonded to a carbide slug that is inserted into the bit body. Means are also provided for limiting the depth of penetration of the diamond cutters into the rock formation being drilled preferably in the form of rolling cone cutters having a plurality of carbide inserts protruding from Their surfaces. The protrusion of the carbide inserts from the surface of the cutter cones is less than the length of …