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 tool break detection system has an automatic gain control to adjust the analog signal channel gain and hold the cutting vibration signal at a desired average level. The AGC time constant is long enough that the detection of abrupt tool breaks and sudden large signal level transistions by the digital signature recognition logic is unaffected. However, the gradual decrease in signal level produced by a crumbly-type break would be removed by AGC action. In a system with a hardware AGC, crossing a high gain threshold resets gain to a low value and the resulting abrupt and persisting change in signal level is detected by the abrupt tool break logic. Another embodiment uses the gain command output by a software AGC and generates a break detected signal directly, without resetting the gain command, as gain rises above a high gain alarm level which is recalculated at the start of each cut.

Abstract: The initial contact of a rotating milling tool to a workpiece is detected in the presence of spurious noise spikes by digitally processing samples of a preprocessed vibration signal concurrently through basic tool touch detection logic and milling tool touch detection enhancement logic, and generating a touch indication if either logic set is satisfied. The basic logic detects a continuously increasing signal level higher than a threshold set above background noise. The milling logic detects an above-threshold signal sample and sets up an acceptance window about the expected time of contact of the next cutter. Tool touch is declared when an above-threshold signal occurs during the window; the milling logic is reset by a noise spike in the interval before the window starts. The basic logic detects tool touch in a dense spiky noise situation.

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: In some machining conditions the background noise in an acoustic cutting tool break detection system is a low mean level with fairly dense high amplitude noise spikes. A common tool break vibration signature is the sudden appearance of a dense spiky noise. Digital signal pattern recognition logic uses an up/down counter to reject the noise on the basis of its lower spike density while alarming on such a tool break signature. Preprocessed vibration signal samples are tested against a detection threshold and an alarm generated if those whose amplitude is above the threshold amplitude exceeds those below by a preset count.

Abstract: Vibrations at the cutting tool-workpiece interface are sensed and the accelerometer output is preprocessed to yield a cutting noise vibration signal. Digital analysis of the sampled signal is performed to detect a gradual cutting noise signal level decrease tool break signature, either continuously decreasing or decreasing in a series of small abrupt steps. A tool break alarm is generated, without false alarming on metal-to-air tool path transitions, as the mean cutting noise signal level falls below an upper check limit and, after a preset time has elapsed, crosses a lower check limit.

Abstract: A Machine Tool Monitor detects the sudden increase in vibration signal level when a slowly advancing cutting tool first touches the workpiece. The delay to a tool touch decision is reduced while still avoiding false alarms on high amplitude single-peaked and multi-peaked noise spikes. Samples of the preprocessed analog vibration signal that are above a low threshold level are analyzed by digital tool touch detection logic. The signal slope polarity is determined by comparison of a new sample to the tracking mean, or by sample-to-sample amplitude comparisons, and presented to an up/down counter. A tool touch alarm is generated when the positive slope counts exceed the negative slope counts by a preset number slightly greater than occur in a time period from the start of a noise spike until its peak amplitude is passed.

Abstract: An AC voltage regulator maintains a predetermined, desired output voltage despite changes in the input voltage, the load, or other operating conditions. The regulator generates an AC reference voltage signal of the same frequency and in phase with the input voltage, and having an amplitude proportional to the predetermined, desired output voltage. The AC reference voltage signal is compared instantaneously to a portion of the actual output voltage to determine an error between the actual output voltage and the predetermined, desired output voltage. The error is instantaneously corrected by altering the actual output voltage to conform to the predetermined, desired output voltage.

Abstract: A highly maneuverable water craft for recreational enthusiasts with two hydraulically controlled and driven reversible propellers directionally fixed to a toroidal peripheral hull section which encircles a thinner interior platform section. The toroidal exterior hull provides stability for the platform in water, allowing the water craft to quickly spin, translate, stop and start. The directionally fixed propellers are not impacted by translation or spin and provide rugged and simplified construction. Placement of two fixed reversible propellers on the peripheral hull section provides maximum turning torque and allows elimination of a rudder or directional actuators. Control is provided by a novel pilot actuator and four-way valves assembly. Bumper strips, propeller guards, handholds and deadman switches can be provided for safety in handling this extremely maneuverable water craft.

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: This computer architecture is optimized for computing the state transitions of a controller, whereas conventional computers are optimized for data manipulation. The concurrent processor for control efficiently implements both the continuous and discrete control functions and has a processing element with two parts, the continuous and discrete processing elements. An arbitrary number of processing elements in a linear array have nearest-neighbor communications, and a general purpose microprocessor is provided to interact with them. Continuous states are computed concurrently and there is provision for interaction between continuous and discrete controls.

Abstract: A servo amplification system is created particularly for heavy construction equipment, but has a general utility that is much broader. The system utilizes a hydraulic analog system with a separate subsystem for each dimension of motion. The operator moves the operative element, such as the backhoe bucket, of the analog replica which ordinarily would be situated in the cab of the backhoe or other piece of equipment. A small hydraulic cylinder operative in response to movement at each articulated connection of the backhoe operates a pilot valve which controls a pilot piston mechanically linked to the drive valve of the drive cylinder of the corresponding articulation in the actual backhoe. A feedback system comprising a mechanical link from the actual drive piston to a feedback cylinder and piston delivers hydraulic fluid back to the inlets of the pilot valve in such a way as to cancel the pilot orders from the initial control cylinder.

Abstract: In a cooking oven which is cleaned by pyrolyzation of soil within the oven cavity and has a smoke eliminator duct extending through the oven wall, with a smoke eliminator heater disposed adjacent to the duct inlet, a reducing gas sensor is mounted either adjacent to the oven end of the smoke eliminator duct or within the smoke eliminator duct near its discharge end. An electrical relay or microcomputer control is coupled between the gas sensor and the heater to initially heat the oven interior and to later deenergize the heater when the reducing gas sensor output indicates a desired oven condition. The oven heaters are temporarily deenergized when the gas sensor output indicate a smoke eliminator overload. If the gas sensor is mounted in the smoke eliminator duct, the smoke eliminator heater may be deenergized toward the end of the cleaning cycle, so that the effluent is not affected by the smoke eliminator heater before reaching the gas sensor.

Abstract: A portable hand held battery operated flashlight having mounted thereon, a magnetic compass which receives illumination from the flashlight or which may have its own illuminating means. The compass is mounted such that compass readings may be taken by the holder of the flashlight whenever the flashlight is illuminated.

Abstract: A servo amplification system is created particularly for heavy construction equipment, but has a general utility that is much broader. The system utilizes a hydraulic analog system with a separate subsystem for each dimension of motion. The operator moves the operative element, such as the backhoe bucket, of the analog replica which ordinarily would be situated in the cab of the backhoe or other piece of equipment. A small hydraulic cylinder operative in response to movement at each articulated connection of the backhoe operates a pilot valve which controls a pilot piston mechanically linked to the drive valve of the drive cylinder of the corresponding articulation in the actual backhoe. A feedback system comprising a mechanical link from the actual drive piston to a feedback cylinder and piston delivers hydraulic fluid back to the inlets of the pilot valve in such a way as to cancel the pilot orders from the initial control cylinder.

Abstract: A cavity, such as an oven cavity, is heated by at least one monolithic integrated heat source, each fabricated by depositing a layer of resistive material on a substrate of non-conducting, or insulating, material. A pair of spaced-apart conductive elements contact opposite ends of the resistance sheet to enable a flow of current through the sheet thereby producing substantially uniform heating over the entire area covered by the resistive sheet.

Abstract: A B-scan ultrasonic imager such as a single-sector scanner has a dynamic aperture and focus control to attain improved lateral resolution especially at ranges less than the maximum array aperture. As the range from which echoes are being received propagates out, the array aperture during each echo reception period is increased by steps by switching in more elements of the total transducer array. At least one adjustment of receiving channel time delays is made to dynamically focus the echoes at different focal points.