Tool for drilling bore holes and earth formations in which a bit body matrix, including tungsten carbide, has a plurality of carriers secured thereto, to each of which a cutting element is secured by soldering, after the body matrix has been produced, to avoid subjecting the diamond material embodied in the cutting element to the high temperatures required to produce the matrix body, which would have deleterious effects on the diamond. Each carrier has great rigidity and is provided with a plane surface confronted by the plane back surface of the cutting element to provide a desired narrow solder gap between the cutting element and carrier of uniform width, into which the solder is deposited to adhere the cutting element and carrier together, with the load being transmitted directly from the cutter element to the rigid carrier.
A replaceable stud cutter for use in matrix drag bit is provided by furnacing a ductile metallic receptacle within the body of the drag bit as it is fabricated. The metal receptacle is characterized by having a receiving cavity defined therein and by including various mechanisms such as grooves or flares which facilitate retention of the metallic receptacle within the matrix body. The lowermost portion of the receptacle within the matrix body may also be shaped or tapered to allow dense packing of the receptacle adjacent to other receptacles along a given radial line on the bit face. A replaceable cutter is brazed, adhesively bonded and/or mechanically locked within the receiving cavity defined in the metal receptacle. When the replaceable cutter becomes worn through normal use, the mechanical locking elements can be drilled out, the brazing melted or adhesive dissolved to allow insertion of a new replacement cutter without causing any damage or alteration either to the receptacle, matrix body or bit face.
The body of a rotary drill bit is formed from a matrix formed by a powder metallurgy process, and a plurality of cutting elements are mounted on the bit body, each cutting element being in the form of a disc of superhard material which is thermally stable at the temperature of formation of the matrix. The front surface of each cutting element is engaged by a holding structure on the bit body in front of the cutting element, the arrangement of the holding structure being such that the resistance provided by the holding structure to forward deflection of the portion of the cutting element opposite the cutting edge is less than the resistance to rearward deflection provided by the surface behind the cutting edge. Bending stresses imparted to the cutting element by rearward deflection thereof in the vicinity of the cutting edge are thereby reduced.
A new and improved drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face, preferably at an angle of about 10.degree.-25.degree. relative to the longitudinal axis of the body, and consist of a passage in the bit body and a removable and interchangeable nozzle member. The nozzle member is secured in place either by peripheral grooves and snap rings or aligned smaller passages in the nozzle member and the bit body having a retaining pin positioned therein. The cutting face preferably has a plurality of recesses therein which receive, by an interference fit, a plurality of cutting elements of the type known as STRATAPAX, consisting of a cylindrical stud having an angular supporting surface with a cutting disc bonded thereon consisting of sintered carbide having a cutting surface of polycrystalline diamond. The studs of the cutting element may have a groove along one side which aligns with a small recess along the side of the cutting element recess to receive a metal pin operable to secure the cutting element in place and against twisting. Additionally, an offset counterbore may be provided at the top of the cutting element recesses which provide for stress relief of the cutting elements during cutting operation.
4373593 - Drill bit - Owned by Christensen, Inc. (Salt Lake City, UT) [*] Notice:The portion of the term of this patent subsequent to February 24, 1998 has been disclaimed.
A rotary boring bit for boreholes comprises a body provided on its outer periphery with cutting members (6) consisting of a cutting portion (8) and a supporting portion (7), each cutting member being formed as a segment of a sintered body (1) having a core (3) of cutting material encased by a shell (2).
A cutting member for rotary drill bits for deep-well drilling in ground formations consists of a carrier member (1) with a supporting surface (3) and a supporting member (4) of hard metal rigidly connected to this at its back and with a cutting layer (5) of polycrystalline synthetic diamond material. The supporting member (4) together with its cutting layer (5) is cut out of a circular cylindrical shaped body or made as a segment and together with its cutting layer occupies only a portion of the supporting surface (3) of the carrier member (1), the remaining supporting surface being occupied by a supplementary member (6) of hard metal or other high-strength substances. With regard to the cutting performance and effect, the same requirements are met as with a circular diamond cutting plate while at the same time considerable savings are achieved in valuable diamond material.
