Abstract: Roller cone drilling wherein the bit optimization process equalizes the downforce (axial force) for the cones (as nearly as possible, subject to other design constraints). Bit performance is significantly enhanced by equalizing downforce.

Abstract: A rotary cone drill bit is provided with at least one cutter cone assembly having a machined cutting structure which will maintain an effective cutting profile despite abrasion, erosion and/or wear of the associated cutting elements. The machined cutting structure may be formed on a generally cone shaped blank by a series of lathe turns and/or plunge cuts. The cutting elements may be formed with an aggressive cutting profile. For one application, the crest of each cutting element has the general configuration of an ogee curve. A layer of hardfacing material may be applied over all or selected portions of the machined cutting structure.

Abstract: An apparatus for processing a graphics request stream begins processing subsequent vertex data while processing previous vertex data. To that end, the apparatus has a vertex assembler having an input for receiving graphics requests, and a processor (coupled to the vertex assembler) for processing received graphics requests. The processor provides a headstart signal to the vertex assembler to indicate that the processor is processing a new graphics request. Upon receipt of the headstart signal, the vertex assembler causes the processor to restart processing of the new graphics request if the new request is determined to have not been properly assembled.

Abstract: A converter for reducing the amplitude of a DC input signal includes first and second switches that each are coupled between an input port for receiving the input signal, and voltage reducing circuitry for reducing the amplitude of the input signal. The two switches are configured so that at least one of the switches is open at all times, thus reducing the heat generated by either one of the switches. This consequently reduces the need for heat dissipation devices such as, for example, conventional heat sinks. Moreover, the two switches each may be smaller than that which would be used if a single switch were used since their duty cycles are much smaller than that of such single switch. The converter further includes an output port coupled to the voltage reducing circuitry for providing an output signal having an amplitude that is less than that of the input signal.

Abstract: A graphics processor for processing vertices of a polygon includes an input for receiving an instruction for processing a given vertex, memory for storing a first lookup table and a second lookup table, and an interpolation engine that, responsive to receipt of the instruction from the input, selects one of the lookup tables, determines table output from the one of the lookup tables, and produces an output value based upon the table output and data relating to the given vertex. Each of the first and second lookup tables may correspond to a selected function and contains table output as a function of an input value. The input value corresponds to data relating to the given vertex.

Abstract: An insert is provided for a rock bit for drilling bore holes in the ground and other downhole tools. The cutting portion of the inserts consist of encrusted cubic boron nitride pellets, tungsten carbide particles and a binder material which are fused together to form a unitary body. The cubic boron nitride particles of the fused insert are cubic in structure and substantially free of heat degradation and resultant hexagonal crystalline structure in response to fusing the elements together in a single step of simultaneously heating and compacting the elements.

Abstract: A process for monitoring the state of microcrystalline change of solid materials, by observing the frequency of a load-pull oscillator which is RF-coupled to the material under test (preferably by a simple single-ended RF probe). Areas where this technique is of particular interest are in monitoring the curing of shaped aerodynamic composite materials, and in monitoring the curing of concrete and cement compositions.

Abstract: A graphics processing chip which uses a deep pipeline of multiple asynchronous units to achieve a high net throughput in 3D rendering. Preferably reads and writes to a local buffer are provided by separate stages of the pipeline. Preferably some of the individual units include parallel paths internally. Preferably some of the individual units are connected to look ahead by more than one stage, to keep the pipeline filled while minimizing the use of expensive deep FIFOs.

Abstract: A wear resistant cutter insert structure and method include a stud having at least one face. A primary tapered ridge and at least one secondary tapered ridge extending from the primary tapered ridge are formed in the face. A layer of abrasive material is disposed over the face covering the primary and secondary tapered ridges.

Abstract: Hardfacing to protect wear surfaces of drill bits and other downhole tools having coated cubic boron nitride particles or coated particles of other ceramic, superabrasive or superhard materials dispersed within and bonded to a matrix deposit. The coating on the ceramic particles or particles of other hard materials may be formed from materials and alloys such as tungsten carbide, and tungsten carbide/cobalt and cermets such as metal carbides and metal nitrides. The coated particles are preferably sintered and have a generally spherical shape. The coated particles are pre-mixed with selected materials such that welding and cooling will form both metallurgical bonds and mechanical bonds within the solidified matrix deposit. A welding rod may be prepared by placing a mixture of selected hard particles such as coated cubic boron nitride particles, hard particles such as tungsten carbide/cobalt, and loose filler material into a steel tube.

Abstract: A clip or protrusion which is built into the mechanism of a parking meter allows the mechanism to be attached outside the meter housing in an upright position so that it can be evaluated and simple repairs can be performed quickly without dropping the mechanism onto the pavement. By designing the clip with tapered notches, the mechanism can be attached to various thicknesses or styles of meter housings.

Abstract: The present application discloses a metal-to-metal antifuse with an amorphous carbon dielectric which provides a very high resistance off state and can be programmed at voltages compatible with deep submicron devices. Furthermore, the programmed filament achieves low resistance with low programming current while maintaining a high level of stability.

Abstract: A method and apparatus are provided for use in fabricating rotary cone drill bits from multiple drill bit segments. Each drill bit segment (40) preferably includes a first portion (50) with mating surfaces (61, 62) designed to be aligned with mating surfaces (61, 62) of other drill bit segments (40) and a second portion (80) which includes a support arm (90) with a cutter cone assembly (100) rotatably mounted thereon. A recess (70) having a generally spherical surface is formed within the first portion (50) of each drill bit segment (40) such that when the respective drill bit segments (40) are aligned with each other, the spherical recesses (70) cooperate with each other to define a generally spherical cavity. A ball (72) is disposed within the resulting spherical cavity when the drill bit segments are joined with each other to form the bit body (42) for the resulting rotary cone drill bit (20).

Abstract: A rendering processor with texture processing capability, in which textures are retrieved from local storage as n.times.n patches. By retrieving a multi-pixel patch on each memory read, the frequency of memory accesses and page breaks in particular are reduced, resulting in a lower memory access time overhead.

Abstract: The improved insert for a ground engaging tool, with a plurality of sockets for receiving a respective insert comprises a body having first and second portions and first and second zones. The first zone may consist of tungsten carbide and metallic cobalt, with preselected dimensions adapted for press fitting within a respective socket of the ground engaging tool. The second body portion may define an earth engaging portion. The second zone may consist of encrusted diamond pellets, tungsten carbide and metallic cobalt, fused together. The first and second zones may be fused together with the first zone being substantially free of encrusted diamond pellets.

Abstract: A novel and improved roller cone drill bit and method of design are disclosed. A roller cone drill bit for drilling through subterranean formations having an upper connection for attachment to a drill string, and a plurality cutting structures rotatably mounted on arms extending downward from the connection. A number of teeth are located in generally concentric rows on each cutting structure. The actual trajectory by which the teeth engage the formation is mathematically determined. A straight-line trajectory is calculated based on the actual trajectory. The teeth are positioned in the cutting structures such each tooth having a designed engagement surface is oriented perpendicular to the calculated straight-line trajectory.

Abstract: A relief valve for use in roller cone drilling bits of the sealed bearing type and other types of sealed fluid systems. The relief valve includes a valve body arranged to fit into the lubricating system of the bit and an elastomeric valve member having a flow port therein that is normally closed. The valve member includes a flexible lip defining the port that is arranged to permit flow in one direction through the port to relieve pressure above a predetermined value while preventing flow therethrough in the opposite direction.

Abstract: A non-plugging nozzle and self-cleaning drilling tool incorporating the nozzle is provided. The nozzle has a body that defines a central passageway extending axially from the top to the bottom of the body. The central passageway defines an inlet orifice at the top and an exit orifice at the bottom. A side passageway extends through the side wall of the nozzle and communicates with a cylindrical portion of the central passageway, the intersection of which defines a side inlet orifice that is substantially square. Because the intersection is substantially square, particles may not become trapped within the nozzle and plug the side passageway. When incorporated into a drilling tool, particularly a polycrystalline diamond compact (PDC) bit, the drilling tool becomes self cleaning. The side passageway of the nozzle is directed at the voids formed in the cutting face of the drilling tool creating a cross flow through the voids and preventing accumulation and balling therein.

Abstract: A sense and protection circuit against short circuits for digital outputs, comprising a logic gating circuit of the exclusive OR type (EX1) which has a first input terminal connected to a signal input node (IN) and an output terminal which is connected to an input terminal of a signal level shifter output stage (B). A second logic gating circuit of the exclusive OR type (EX2) has a first input terminal connected to the input node (IN) and a second input terminal connected, through an inverting circuit (IN1), to an output terminal (OUT) of the output stage (B). A second input terminal of the first logic gate circuit is coupled to an output terminal of the second logic gate circuit through a comparator circuit (SCH1) and a delay circuit means (C,R,D).

Abstract: An electronic driver circuit for low-impedance loads, being of a type which comprises an input terminal (IN) to which a voltage signal (Vin) is applied for alternate transfer to an output, and a plurality of output terminals (OUTi), each connected to a corresponding electric load (2), further comprises, between the input terminal and the output terminals, a single operational amplifier (3) having multiple output stages (7), one for each output terminal (OUTi). The operational amplifier (3) is of the single-ended or fully differential multistage type and allows each load to be driven alternately by activation of the corresponding output stage (7i).