Abstract: Dual functioning seals for use in forming a lubricant seal in a rotary rock bit comprise an annular elastomeric seal body having a dynamic seal surface for sealing against a dynamic surface and a static seal surface for sealing against a static surface. The seal body has an asymmetric axial cross-sectional geometry the dynamic seal surface having a greater radius of curvature than that of the static seal surface. The dynamic and static seal surfaces are formed from different elastomeric materials, and the dynamic seal surface is formed from an elastomeric material that is harder and more wear resistant than the elastomeric material used to form the static seal surface. A rotary rock bit seal constructed in this manner is well adapted to accommodate the different operating conditions and sealing requirements that exist both at the dynamic and static surfaces of the seal to ensure optimal seal performance and, thereby enhance the service life of the rock bit.

Abstract: A rotary cone bit for drilling bore holes in earth formations whose body has a thread pin end and a dome end from which extend three legs. A cutter cone is rotatably mounted to each leg and is radially oriented about the bit's central axis. Each cutter cone has a gage row of cutting elements extending from the cone surface nearest the mouth and a nose row extending nearest the cone's apex. A center jet for emitting fluid or mud is located on the dome. The jet has a converging nozzle with an exit orifice which extends below a predefined horizontal plane intersected by the cones or cutting elements. The exit orifice has a constant diameter for a length at least equal to its diameter for reducing the diffusion of the fluid or mud flow emitted. Fluid or mud emitted from the center jet travels substantially uninterrupted within a cylindrical space between the cones which is not invaded by any cutting element.

Abstract: Dual functioning seals for use in forming a lubricant seal in a rotary rock bit comprise an annular elastomeric seal body having a dynamic seal surface for sealing against a dynamic surface and a static seal surface for sealing against a static surface. The seal body has an asymmetric axial cross-sectional geometry the dynamic seal surface having a greater radius of curvature than that of the static seal surface. The dynamic and static seal surfaces are formed from different elastomeric materials, and the dynamic seal surface is formed from an elastomeric material that is harder and more wear resistant than the elastomeric material used to form the static seal surface. A rotary rock bit seal constructed in this manner is well adapted to accommodate the different operating conditions and sealing requirements that exist both at the dynamic and static surfaces of the seal to ensure optimal seal performance and, thereby enhance the service life of the rock bit.

Abstract: An improved polycrystalline diamond composite ("PDC") cutter comprises a single or a plurality of secondary PDC cutting surfaces in addition to a primary PDC cutting surface. The two cutting surfaces are spaced apart, resulting in enhanced cutter efficiency and useful life. The primary PDC cutting surface is a polycrystalline diamond layer on an exposed end face of the cutter. A secondary cutting surface is formed by a polycrystalline diamond layer embedded within the body of the cutter. The secondary cutting surface can have a larger diameter than the primary cutting surface so that the forward end of the cutter parallels rock formation during drilling and both cutting surfaces engage the rock formation.

Abstract: A nozzle retention receptacle for rotary cone rock bits consists of a nozzle retention receptacle body forming a fluid passage therethrough. The body forms a first upstream entrance end that forms part of a wall of a plenum formed within a rock bit body and a second downstream exit end. The upstream end further forms a mounting interface that circumvents a fluid entrance port to the passage in the nozzle retention receptacle. The port communicates with the fluid plenum in the bit body. The body of the rock bit further forms a nozzle retention receptacle mounting interface that is common to the mounting interface formed by the nozzle retention receptacle.

Abstract: A nozzle sleeve for the retention of replaceable fluid nozzles for rock bits is disclosed. The sleeve is secured within the body of the rock bit. A first upstream end of the sleeve communicates with a fluid plenum formed by the bit body. A second downstream end of this sleeve is adapted to receive the fluid nozzles. An elliptical fluid entrance is formed at the first upstream end of the nozzle sleeve. The elliptical fluid inlet formed by the sleeve serves to increase the flow of fluid to the nozzles, reduce turbulence of the fluid and substantially reduce the erosive effects associated with high fluid velocities and turbulent flow.

Abstract: A composite mini-extended nozzle is disclosed that is designed to both resist erosion and be strong enough to withstand the shock of a downhole drilling environment. In addition, means are provided to shroud at least a portion of the extended nozzle to further protect a portion of the nozzle nearest the exit plane from downhole obstructions. A combination of materials used to form the nozzle may include a matrix of tungsten carbides with suitable binder joined to an outer metal jacket nozzle body. A third ceramic matrix material may be utilized to line or partially line an interior passage formed by the mini-extended nozzle and a reduced in diameter portion of the nozzle design may include a built-in fracture plane in the unlikely event the end of the nozzle hits an obstruction. The extended portion of the nozzle will shear off along this fracture plane thereby preventing a nozzle washout that likely would result in a trip out of the hole to repair the resultant damage to the rock bit.

Abstract: A chisel type insert is disclosed having a contoured surface in which the vertical lines located on the surface are bowed outwardly in a convex manner thereby eliminating blend radii from the cutting tip and the high stress concentrations associated therewith.

Abstract: A rotary cone rock bit for drilling boreholes in an earthen formation is disclosed. One or more rotary cones are rotatively retained on a journal bearing connected to the rock bit. These rotary cones form a circumferential heel row with extended ultra hard shaped cutters spaced within the heel row. Each of the shaped cutters form a cutting surface that extends above the heel row or is angled with respect to the formation to maintain the cutters in compression while the cutters shear a borehole wall. The shaped cutters serve to maintain the borehole diameter.

Abstract: A rotary cone rock bit for drilling boreholes in an earthen formation is disclosed. One or more rotary cones are rotatively retained on a journal bearing connected to the rock bit. These rotary cones form a circumferential heel row with extended ultra hard shaped cutters spaced within the heel row. Each of the shaped cutters form cutting edges that shear a borehole wall formed by the formation as the rotary cone rotates against a bottom of the borehole formed by the formation. The shaped cutters serve to maintain the borehole diameter and to divert formation debris away from bearing surfaces formed between the rotary cone and the journal bearing.

Abstract: A tungsten carbide chisel insert for rock bits is disclosed having a cylindrical base section and a cutting tip section, the top of the tip section having an elongated crest, the remainder of the cutting tip section below the crest is a contoured surface formed having cross-sections being shaped as to provide for better overall performance.

Abstract: A chisel gage insert is disclosed having a larger nose radius at the outer end of the insert crest than at the inner end thereby providing more mass on the portion of the insert that contacts the borehole sidewall. The rounded crest also blends with the convex surfaces of the insert extension so as not to have any non-tangential intersections.

Abstract: A chisel insert for rolling cone rock bits is disclosed in which the crest of the insert has a "dog bone" shape by being rounded with the crest ends flaring out to a larger dimension than the middle thereof. The crest is also convex upwardly along its median line thereby making a shorter moment arm at the ends of the crest.

Abstract: A nozzle sleeve for the retention of replaceable fluid nozzles for rock bits is disclosed. The sleeve is secured within the body of the rock bit. A first upstream end of the sleeve communicates with a fluid plenum formed by the bit body. A second downstream end of this sleeve is adapted to receive the fluid nozzles. An elliptical fluid entrance is formed at the first upstream end of the nozzle sleeve. The elliptical fluid inlet formed by the sleeve serves to increase the flow of fluid to the nozzles, reduce turbulence of the fluid and substantially reduce the erosive effects associated with high fluid velocities and turbulent flow.