Abstract: A current limiting system for a circuit limits current flow through the system. The current limiting system comprises at least one main switch comprising first and second main switch contacts and a contactor connecting the first and second main switch contacts; at least one current limiting device and at least one solid-state switch, which are mechanically unconnected to the main switch, and the at least one current limiting device and least one solid-state switch are arranged in series on a series side of the circuit; the at least one main switch is on a main switch side of the circuit arranged in parallel with the series side; a control that senses a predetermined condition of the circuit, and operably connected with the at least one solid state switch to open and it. Under normal operating conditions, most current flows through the at least one main switch side. When the predetermined condition causes the main switch to open, and the resistance increases in a main switch side.

Abstract: An AC contactor having a high recovery voltage strength includes a contact assembly and a high recovery voltage gas system coupled to the contact assembly. The contact assembly includes two contact pads per electrical phase, with one of the contact pads being attached to a positioning device that selectively disposes the contact pad between a closed circuit position and an open circuit position. The high recovery voltage gas system includes a thermal gas evolving medium for introducing a high recovery voltage strength gas into the gap between the contact pads, which gas has a high glow discharge cathode voltage fall value, as determined for silver-based contacts, of not less than about 300 volts, and typically greater than about 500 volts. The high recovery voltage strength gas typically comprises carbon monoxide, carbon dioxide, water vapor, or the like. The thermal gas evolving medium typically is as a Group IA carbonate (e.g., sodium bicarbonate), and is disposed in the contact assembly.

Abstract: An improved x-ray system/tube comprising an enclosure having oil contained therein, an oil pump, for circulating oil within the system, at least one cooling structure operatively connected to the enclosure and the oil pump, for cooling the oil, an x-ray tube, operatively positioned inside the enclosure for generating and directing x-rays toward a target, the x-ray tube comprising: a glass envelope, a cathode, operatively positioned in the glass envelope, an anode assembly including a rotor and a stator, operatively positioned relative to the rotor, a target, operatively positioned relative to the cathode and operatively connected to the anode assembly, for directing x-rays out of the system, and bearing structure having opposing surfaces and lubricant means having debris therein, operatively connected to the anode assembly, for enabling the target to rotate at a high rate and at a low resistance, the bearing structure including means for capturing the debris such that bearing performance is maintained at or n

Abstract: An improved high performance x-ray tube having a rotating graphite anode therein and method of preparation thereof. The surface of a graphite anode body is oxidized in air for removing the surface damage caused during the machining of the anode body. The anode body is provided with a diffusion barrier layer of rhenium contiguously disposed on the substantially damage free surface of the anode body. An anode target layer is then deposited on top of the barrier layer.

Abstract: An improved high performance x-ray tube rotating having a graphite anode therein and method of preparation thereof. A graphite anode body is provided with a microcracked contiguously disposed diffusion barrier layer of rhenium on the surface of the anode body. An anode target layer is then deposited on top of the barrier layer.

Abstract: A method and apparatus for parting a deck of amorphous alloy ribbons in one operation is disclosed. Force is applied to a deck of ribbons to place it under tension. A localized zone in the deck is compressed and rapidly heated to the softening temperature of the amorphous alloy. The deck separates along a seam within the zone due to the tensile force and localized rapid heating. A high quality edge is produced where the separated ribbon edges are free of burrs, meltbeads or substantial cracking and chipping.

Abstract: For shear-cutting a stack of thin sheets of amorphous steel along a cutting plane that extends transversely of the stack, we utilize apparatus that comprises two blades that are positioned at the start of a cutting operation on opposite sides of the stack. Each of the blades has a first surface for engaging one side of the stack and a second surface extending transversely of the first surface and generally parallel to said cutting plane and intersecting the first surface at a corner. The first surface of each blade is disposed at a predetermined rake angle with respect to a reference plane extending through a point on the corner of the blade and normal to said cutting plane. By making the sum of these rake angles of a negative value and beween 5 and 35 degrees, we are able to substantially improve the wear resistance of the blades and lengthen their working life.

Abstract: Sharp tools have different cutting characteristics from dull or worn tools. Among these differences is that a wear land develops on the cutting tool so that more of the cutting tool comes into contact with the workpiece during the cutting process. The increased contact area between the tool and workpiece forces more energy to be consumed by the cutting machine in making a cut because more energy is expended in non-productive work. Indications of an increase in non-productive work are the increased power or force necessary to operate a spindle in lathes, milling machines, etc., and the increased energy in cutting vibrations in a low frequency range emitted during the cutting process. Another indication of decreased efficiency of the cutting process is the decreased energy in cutting vibrations in a high frequency range emitted during the cutting process.

Abstract: A cutting tool is monitored on-line by measuring the heat generation rate at the cutting edge and relating this to the condition of the cutting edge. A flow of fluid coolant contacts the back surface of the cutting tool and the coolant temperature rise is measured during the machining process. The temperature difference and its rate of rise or fall is a direct indication of the heat generation rate and is related to tool conditions such as excessive and rapid wear and breakage. In the case of inserts, coolant channels are formed in the reusable seat, and tool holder channels provide for flow of coolant to the seat.

Abstract: High-strength, fine-grain, multi-phase substantially crystalline sintered ceramic bodies are produced by a process comprising the steps of cold pressing, followed by sintering at a high temperature, of a mixture of different powdered ceramic materials containing non-inhibitory components and a source of inhibitory components that can chemically interact at elevated temperatures generate gases which hinder densification or form phases undesirable for sintering provided that there is also included in the mixture an amount of a source of a component co-reactive with the gases produced by the inhibitory components at elevated temperature to achieve efficient densification and retention of properties in the sintered body.

Abstract: A Machine Tool Monitor detects significant cutting tool breakage and the first contact of an advancing tool to a workpiece, and does this by monitoring vibration signals produced by the machining of parts and interpreting patterns in these signals. Information from the part program improves the performance of the detector and optimizes it for the cutting conditions called for by the machine tool control. The analog channel gain of the monitor is adjusted and parameters controlling the digital pattern recognition logic are selected using part program information on machining parameters. The tool touch or tool break detection mode is selected by the part program.

Abstract: Substantial cutting condition changes that occur gradually, as opposed to the more usual sudden large change, are detected by setting upper and lower cutting noise mean level thresholds. When the mean cutting noise exceeds the upper threshold or stays below the lower threshold for a preset number of signal samples, a tool break alarm is generated. Techniques are given to reduce false alarms at the start and end of the cut and on runout on initial rough surface cuts. The system comprises an accelerometer or other sensor whose signal is preprocessed to attenuate lower frequency machinery noise and detect the signal energy in a band below 100 KHz, then sampled, and the digitized signal samples analyzed by pattern recognition logic.

Abstract: A system and method for monitoring vibrations of a cutting tool produced by tool break events, and for interpreting them to detect tool breaks of sufficient magnitude to endanger the machined part. The signal generated by a sensor such as an accelerometer is preprocessed to attenuate low frequency machining noise and detect the energy in a higher frequency band, then sampled, and the digitized signal samples analyzed by tool break detection logic. This logic is triggered by a positive-going signal transient, and prevents false alarms on minor tool break events that do not mar the workpiece and on noise from other sources.

Abstract: This tool break detection system relies on monitoring changes in the cutting noise itself, rather than detecting the tool fracture acoustic signal. A broken tool capable of damaging the workpiece is detected, and tool break events that do not affect cutting conditions are ignored. The signal from a sensor such as an accelerometer is preprocessed to attenuate low frequency machinery noise and detect the signal energy in a band below 100 KHz, then sampled, and the digitized signal samples analyzed by pattern recognition logic. Runout false alarms during rough surface cutting are prevented; after detection of an abrupt increase or decrease in signal level, the confirmation period to test for a persistent shift in mean level is set longer than the workpiece revolution period.

Abstract: A system and method for monitoring vibrations of a machine tool metal-cutting tool insert and interpreting them to promptly detect the initial touch to the workpiece and signal the tool to stop advancing before marring the surface. The signal generated by a sensor such as an accelerometer is preprocessed to eliminate lower frequency machine noise and detect the energy in a higher frequency band, then sampled and analyzed by digital circuitry. In order to avoid false alarms on high amplitude spiky noise pulses generated by traverse operation of the machine tool, the tool touch alarm is delayed longer than the maximum duration of the noise pulses. Two techniques are given to ignore the noise spikes while still detecting the tool touch signal.

Abstract: A self-sharpening refractory metal cutting tool presenting an overhanging cutting portion, i.e. a flange, or ledge, of width equal to (or slightly greater than) the depth of the cut to be taken and maximum thickness equal to tolerable tool flank wear is disclosed. This tool construction has special utility in a novel high-speed cutting method in which only the tool flange does the cutting in which operation the flange is worn away with the wear progressing lengthwise of the flange during which time the flange sequentially performs a roughing cut and then a finishing cut in a single pass.

Abstract: A particulate mixture of ceramic powder, boron and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with boron producing a polycrystalline microcomposite comprised of a continuous phase of the boride of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.

Abstract: A particulate mixture of ceramic powder, free carbon and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with carbon producing a polycrystalline microcomposite comprised of a continuous phase of the carbide of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.

Abstract: A particulate mixture of ceramic powder, free carbon and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with carbon producing a polycrystalline microcomposite comprised of a continuous phase of the carbide of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.

Abstract: A particulate mixture of ceramic powder, boron and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with boron producing a polycrystalline microcomposite comprised of a continuous phase of the boride of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.