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Patent

Magnetostrictive linear position detector with reflection termination

TL;DR: A magnetostrictive linear displacement detector with increased position resolution was proposed in this paper, where the displacement is determined from the interval of time between the detection of the torsional motion traveling directly from the magnet and the detection reflected from the reflection termination.
Abstract: A magnetostrictive linear displacement detector with increased position resolution includes a magnetostrictive wire anchored at opposite head and foot ends with a reflection termination at the foot end and a damping termination at the head end. A return wire is connected to the foot end of the magnetostrictive wire. The magnetostrictive wire is electrically excited at its head end. A variable position to be detected is represented by a magnet disposed for displacement along the magnetostrictive wire. A torsional motion sensor at the head end generates an electrical indication of the torsional motion within the magnetostrictive wire induced by passage of the electrical excitation by the position of the magnet. The displacement is determined from the interval of time between the detection of the torsional motion traveling directly from the magnet and the detection of the torsional motion reflected from the reflection termination. The reflection termination preferably consists of a brass cylindrical torus having a hole through which said magnetostrictive wire is passed and attached via a set screw. In an alternative embodiment the magnetostrictive wire is torsionally excited and the responses are detected electrically.
Citations
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Patent
29 Dec 2000
TL;DR: In this paper, an integrated vehicle ride height system control system was proposed for use with a motor vehicle having at least one fluid-pressurized height adjusting member having first and second separable components.
Abstract: The present invention is intended for use with a motor vehicle having at least one fluid-pressurized height adjusting member having first and second separable components. Apparatus constructed in accordance with the invention includes an integrated vehicle ride height system control system. The control system includes an electronic output drive signal circuit and input signal interpretation circuit to electronically interface with at least one position sensor. The position sensor provides output signals related to extent of separation of said first and second separable components of the fluid pressurized height adjusting member.

85 citations

Patent
20 Jul 1992
TL;DR: In this article, a position detection probe has a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot as a position detector, compensation for thermal expansion and thermal change of propagation velocity is made based on the property of the total propagation time along the wire length being a unique function of temperature.
Abstract: In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made based on the property of the total propagation time along the wire length being a unique function of temperature and calibrating the probe at different temperatures to yield either equations or look up tables of true positions as functions of the total propagation time and the position detection parameter. By mapping wire characteristics at a plurality of magnet positions and temperatures to construct look up tables, wire nonlinearities as well as thermal effects can be compensated for.

46 citations

Patent
17 Apr 1991
TL;DR: In this paper, a magnetic sight gage sensor comprises a sensor for determining the liquid level in a process vessel utilizing a magnetic float on the interior of a tube or sight glass, which is made of a non-magnetic material in order to allow transmission of the magnetic field from the float to the transducers.
Abstract: A magnetic sight gage sensor comprises a sensor for determining the liquid level in a process vessel utilizing a magnetic float on the interior of a tube. The tube is connected at different levels to a process vessel and contains a liquid that is maintained at the same level as the liquid inside the process vessel. A magnetostrictive displacement transducer is coupled to the tube or sight glass on the exterior of such glass, so it is out of the process fluid. The transducer provides signals indicating the position of the float relative to a reference position on the transducer. The tube or sight glass is made of a non-magnetic material in order to allow transmission of the magnetic field from the float to the transducer.

39 citations

Patent
18 Feb 1993
TL;DR: In this article, a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot-end termination as a position detector, is made by measuring the wire resistance and calculating a compensation from the resistance.
Abstract: In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot end termination as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made by measuring the wire resistance and calculating a compensation from the resistance. The probe is excited by an electrical pulse having a known current. The voltage across the wire is measured at a time when the current has stabilized to a precise value, and resistance is determined from the current and voltage.

38 citations

Patent
14 Mar 1994
TL;DR: In this article, a magnetostrictive liquid level probe in a double-walled liquid container develops liquid level data and external sensors in the space between the walls respond to the presence of liquid leaked into the space from inside or outside the container.
Abstract: A magnetostrictive liquid level probe in a double-walled liquid container develops liquid level data and external sensors in the space between the walls respond to the presence of liquid leaked into the space from inside or outside the container. Other sensors external of the liquid level probe may sense other conditions. The probe electronics determines binary states of the external sensors and digitally encodes the states for inclusion in data transmission of the liquid level information to a remote controller via a two-wire transmission line. One embodiment develops pulses spaced as a digital function of the sensor states and includes liquid level data between the pulses for transmission. The pulse space is measured at the remote controller and decoded to determine the external sensor states, while the liquid level data is analyzed to determine the contents of the container.

34 citations

References
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Patent
19 Dec 1973
TL;DR: In this paper, a linear distance measuring device is disclosed in which the time it takes a torsion pulse to traverse a sonic waveguide from a movable magnet to a pulse responsive element is determined and converted to a measurement of the distance from the movable magnets to the pulse responsive elements.
Abstract: A linear distance measuring device is disclosed in which the time it takes a torsion pulse to traverse a sonic waveguide from a movable magnet to a pulse responsive element is determined and converted to a measurement of the distance from the movable magnet to the pulse responsive element The position of the magnet, which is moved by an external means such as a machine tool element, can thus be determined precisely

153 citations

Patent
03 Nov 1975
TL;DR: In this paper, a magnetic field generator is mounted on a movable member and an elongated ferromagnetic member is positioned adjacent and parallel to the path of movement of the member.
Abstract: The position of a movable member is measured without the establishment of physical contact with such member. A magnetic field generator, which provides a localized field of special geometry, is mounted on the movable member and an elongated ferromagnetic member is positioned adjacent and parallel to the path of movement of the member. The magnetic field will produce a change in the Young's modulus of elasticity in an adjacent region of the ferromagnetic member and sonic strain pulses launched along the ferromagnetic member will be partly reflected from this region of Young's modulus discontinuity. The time required for a strain pulse to travel from a given point on the ferromagnetic member to the region of Young's modulus discontinuity and be partially reflected therefrom and returned to a known detection point will provide a measure of the position of the field generator along the elongated ferromagnetic member.

75 citations

Patent
24 Sep 1987
TL;DR: In this paper, a magnetostrictive wire is used to measure liquid level as a function of the elapsed time between an actuation signal and the first zero crossing of the voltage which is induced as the torsional strain passes through the area of influence of the sliding magnet.
Abstract: A liquid level detector of the type in which a magnetostrictive wire extends through the liquid level measurement range and is captured in a tensioned vertical orientation within a stainless steel tube. Liquid level is measured as a function of the time required for a torsional disturbance imparted the wire near the top to travel along the wire to a magnet which is contained within a liquid level float which slides up and down along the tube. The torsional disturbances imparted to the wire by means of a piezoelectric crystal to which the wire is easily clamped. Accuracy is enhanced by measuring liquid level as a function of the elapsed time between an actuation signal and the first zero crossing of the voltage which is induced as the torsional strain passes through the area of influence of the sliding magnet.

55 citations

Patent
29 Jan 1968

53 citations

Patent
04 Nov 1974
TL;DR: In this paper, the authors present an approach for determining linear or angular measurements or measurements of positions on a planar or curved surface, which apparatus uses at least one delay element, such as a magnetostrictive element, which is capable of supporting an accoustic wave signal.
Abstract: Apparatus for determining linear or angular measurements or measurements of positions on a planar or curved surface, which apparatus uses at least one delay element, such as a magnetostrictive element, for example, which is capable of supporting an accoustic wave signal. The one or more delay elements may be in the form of bands, rods, wires, planar or spherical structures, and the like, and can be arranged in various embodiments to provide linear or angular position information for single, dual, and multiaxis geometry. They can be used, for example, to provide single or multispeed resolver operation and three-axis attitude read-out. In preferred embodiments the apparatus uses phase measurement techniques so that high accuracy can be achieved.

44 citations