Abstract: A position and motion transducer is described comprising means for providing a permanent magnetic field adjacent an appropriately oriented toroidal transformer, which can be either an isolation transformer or an autotransformer. The means for providing a permanent magnetic field, in an especially useful embodiment is a permanent magnet cobalt disk magnet with its surface pole facing generally radially in the plane of the torus or generally perpendicular the axis thereof. Appropriate excitation of one winding of the toroidal transformer enables readout equipment connected with the other winding to indicate the position and movement of the magnet relative the toroid. Appropriate mounting of the magnet enables various measurands to be indicated. For example, mounting the magnet on or for movement with a diaphragm enables fluid pressures applied thereto to be measured while mounting the magnet on a spring support force plate or piston/cylinder enables the force or weight applied thereto to be measured.

Abstract: A stress or strain sensor including a magnetic circuit having at least a part constituted by an amorphous magnetic alloy. For detection of the inductance value of the sensor, a DC magnetic field is superposed on an AC magnetic field so that magnetic domains of the alloy tend to be aligned. The sensor output can be increased significantly over that of the conventional sensor in which only the AC magnetic field is employed, while hysteresis of the output is reduced. The temperature characteristic is also improved.

Abstract: A device for sensing pressure at a source thereof comprising a housing with a fluid pressure responsive diaphragm movable therein for defining therewith an expansible chamber for communication with the source of pressure the magnitude of which is to be sensed, and a transducer. The transducer includes a body of magnetoelastic material of generally annular form positioned within the housing and having magnetic properties which vary as a function of the stress to which the body is subjected in response to movement of the diaphragm. Electrical circuitry responds to stress-induced changes in the magnetic properties to produce an electrical signal having a value which is a function of the magnitude of the fluid pressure. The device includes an actuator, which is movable with the diaphragm, for accepting and retaining a sector of the annular body and a cradle generally fixed in relation to the housing for accepting and retaining a diametrically opposite sector of the annular body.

Abstract: A differential pressure transmitter includes a housing, a first chamber within the housing for receiving an input pressure to be sensed and a second chamber for receiving a transmitter adapted to generate an electrical signal representative of the input pressure. The chambers are separated by a continuously formed, highly resilient diaphragm. A reaction member embodied as a resilient spring is disposed in the second chamber for sensing a position of the diaphragm resulting from the magnitude of the differential pressure thereacross. The reaction member has a magnetized structure mounted thereon which coacts with a Hall effect transducer embodied in the transmitter for detecting the relative position of the magnetized structure and therefore of the diaphragm and responsively generating an electrical signal. The signal may be utilized for positioning actuator controlled dampers within a VAV system duct.

Abstract: A pressure switch and transducer arrangement combines into a single unit both a power contact switch for providing power to an automobile fuel pump in response to a predetermined minimum oil pressure and a magnet/Hall effect sensor for providing an analog signal indicative of the oil pressure for use by the automobile on-board microcomputer. The arrangement includes an actuator rod movable by a diaphragm in response to oil pressure. The end of the rod remote from the diaphragm is coupled to a contact washer for providing the power switching function and also to a magnet which cooperates with a fixed Hall effect sensor, which sensor provides an output corresponding to the air gap between the magnet and the sensor. The magnet and the washer are coupled to the actuator rod in such a manner that even after the washer makes contact with the power switching terminals, the actuator rod and magnet are free to continue moving as the oil pressure continues to increase.

Abstract: A transducer apparatus utilizing fiber optics for data transmission is disclosed in which an output optical signal is encoded with information representative of a parameter being measured and the encoded optical signal transmitted to a remote measurement and control apparatus site for decoding. The transducer is adapted to receive an input optical signal, and converts the input optical signal into electrical energy to power a driver. An electrical drive signal, generated by the driver, has a selectively variable frequency representative of the parameter being measured. Using the electrical drive signal, the output optical signal is generated. The driver includes a variable frequency oscillator whose frequency of oscillation is dependent upon the parameter being measured.

Abstract: A deformable pressure chamber (10) moves a permanent magnet (12) carried by it as it is deformed. A GaAs Hall element (13) is disposed on a substrate plate (1) opposite the permanent magnet, and the substrate plate also carries a hybrid circuit including a temperature compensating network of thick film resistors and an amplifier. The Hall element is subject to only small temperature effects, and these are compensated in a circuit that can work with a low supply voltage.

Abstract: A control device and method of making the same are provided, the control device having a housing provided with an actuator chamber separated from a pressure differential chamber by a wall having an opening therethrough receiving an axially movable actuator pin that transmits axial movement of a movable part in the pressure differential chamber to the actuator chamber. A Hall effect transducer is disposed in the actuator chamber and the actuator pin has a magnet unit for operating the transducer as the movable part axially moves the actuator pin relative to the housing, the magnet unit being disposed in offset relation to the axis of the actuator pin and moving in unison therewith relative to the transducer.

Abstract: A knock detecting apparatus for detecting the occurrence of knocking in an internal combustion engine by detecting variations in the pressure of engine cooling water. A sealed double diaphragm structure is formed by a first diaphragm which is directly responsive to variations in the cooling water pressure and not resonant at the knock frequencies and a second diaphragm which is resonant at the knock frequencies. A noncompressible fluid is contained in the sealed double diaphragm structure between the two diaphragms. Pulsations of the second diaphragm, resonant at the knock frequencies, are detected by a magnetic device or a piezoelectric device operative to output an ac signal.

Abstract: A pressure sensor is formed by separating two chambers by a movable member to which is coupled an amorphous metal material. The amorphous metal material is anchored at its other end to be subjected to differing amounts of stress in accordance with movement of the movable member due to pressure changes. The tensile stress applied to the amorphous member is electrically detected, e.g. by detecting the impedance characteristics of an electrical coil adjacent the amorphous member.

Abstract: A knocking sensing apparatus for sensing a knocking taking place in an internal combustion engine. The apparatus includes a diaphragm adapted to operate in response to the pressure of cooling water circulated in the engine, magnetism generating device, magnetic circuit including the diaphragm, and a magnetic flux detecting device adapted to detect in a manner like alternating current the change in the magnetic flux in the magnetic circuit caused by the operation of the diaphragm.

Abstract: A pressure sensing unit for a pressure sensor using the magnetostriction effect of a ferrous amorphous magnetic alloy having elasticity which permits magnetostriction, and including an inductance element which has a magnetic core formed at least in part of the amorphous magnetic alloy and which is subjected to pressure so as to exert pressure on the alloy corresponding to the pressure to be measured, the resulting change in the value of the inductance being used to detect the applied pressure.

Abstract: A pressure-sensing transducer which can be used to continuously measure the pressure in the cylinder of an internal combustion engine comprising a pressure-transmitting element which includes a generally tubular seat and a metallic plate which closes off a top end of the seat, an M-shaped force-transmitting member which spans across the top end of the seat, the outer legs of the M-shaped member being connected to opposite portions of the top end of the seat and the inner legs being connected to the center of the metallic plate, and a magnetoelastic force-sensing member connected between the outer legs of the M-shaped member, such that pressure-generated forces applied to the metallic plate from within the generally tubular seat are transformed into a tensile force acting on the force-sensing member in a direction perpendicular to the longitudinal axis through the generally tubular seat.

Abstract: A pressure responsive control device having a housing carrying a flexible diaphragm therein that cooperates with the housing to define a pressure chamber therein that is adapted to receive a variable pressure that acts against the diaphragm to position the diaphragm relative to the housing in relation to the value of the pressure, the diaphragm being operatively interconnected to a plunger that follows movement of the diaphragm. The control device has a transducer operatively associated with the plunger to produce an electrical signal in relation to the position of the plunger, the transducer comprising a core carried by the plunger in axially aligned relation therewith and an induction coil carried by the control device and receiving the core therein. A range spring is carried by the housing and is operatively interconnected to the diaphragm to tend to oppose movement of the diaphragm in one direction of movement thereof.

Abstract: An improvement in fluid pressure transducers having a housing with oppositely facing magnetic blocks (12,14) that form a sealed chamber (20) in which a magnetically permeable diaphragm (24) is disposed for magnetic coupling with electromagnetic coils (30) mounted within the blocks. The coil is mounted on an elongated plug (34) and covered by a non-magnetic, unitary metal cap (36) that is flexibly sealed between the chamber and the coil. The cap has a generally cup-like inner portion (48) for covering the coil and a flat rim portion (46) that is sealingly (58) secured between the mounting plug and shoulder means (50,60) within the block.

Abstract: Disclosed is an absolute pressure pick-up for the intake in an internal combustion engine. The pick-up consists of a screened magnetic circuit equipped with a mobile core placed inside an elastic bellows. A chamber (4) that receives either the pressure to measure or the reference vacuum is around the bellows.

Abstract: There is disclosed a hydrostatic leveling system including a pair of indicator heads connected by a liquid hose for equilizing static pressure in the liquid mercury pools of the indicator heads and a gas hose for equalizing the gas or vapor pressure within the heads above the pools of mercury. Each head is a float connected to the stem of a precision measuring gauge with graduations on the order of ten-thousandths of an inch. The indicator heads have identical structures and thus when they are resting on a level surface they may be reversed in location without change in gauge indicator reading; any difference in the reading is a measure of out-of-level condition. The space for the pool is sealed with a very flexible diaphragm between the float and the wall of the pool cavity. A plunger in the cavity is operated by a solenoid in the cavity to periodically thump the float to reduce tendency to stick due to surface tension, friction and hysteresis.

Abstract: A pick-up for the intake pressure of a combustion engine of the type with a flexible membrane and electrical translation of the displacement of the membrane, including a spring acting against the member, an adjustment mechanism for positioning the spring acting against the membrane, a guiding tube for the spring serving as a stop for the membrane, a closed magnetic casing made of ferrite including nested cylinders pierced by a hole at each end of their axes, a central ferrite magnetic core connected to the membrane and penetrating the closed magnetic casing, an insulating bobbin disposed within the casing, a single winding placed on the insulating bobbin around the core and covering a major portion of the core in its deepest position, the bobbin further including cylindrical ends extending beyond the magnetic casing on opposite sides thereof so as to form an air pocket between the core and the casing and guide the core in the casing, and an oscillating electronic circuit connected to the winding which include

Abstract: A pressure sensor for measuring the pressure in an aircraft wheel tire comprises a stationary housing and a shaft connected to the wheel. A unit slidably connected to the shaft has a surface cooperating with a pair of bellows coaxial to the shaft to define a pressure chamber. A passage in the shaft communicates the pressure chamber and the tire.

Abstract: Detector comprising two windings (1,2) disposed in two ferrite half-pots (3,4) opposite to two non-ferromagnetic metallic elements (5,6) one at least of which is movable. A pulse generator (9) feeds the two windings through resistances (7,8) coupled to a reference potential.Two circuits (10,11) detect the peak values of the resultant signals at the common points between the windings and their charging resistance. An operational amplifier (12) creates the difference of these peak values. A diode (13) permits the discharge of the windings through the resistances (7,8).Application to detectors of differential pressure, and to devices for the measurement of displacements.

Abstract: A pressure sensor comprising a pressure-displacement transducer mechanism including a movable body driven by a hydraulic pressure to be determined and spring means for urging the movable body in a direction opposite to the pressure, and a displacement-pulse phase conversion unit including a ferromagnetic member secured to the movable body, a magnetically soft member carrying an electrical coil thereon and disposed at a stationary point adjacent to the region of movement of the ferromagnetic member and a permanent magnet. A pulse voltage is applied to one end of the electrical coil, the other end of which is connected in series with a resistor. A voltage drop across the resistor is detected, and a time lag of the voltage drop with respect to the pulse voltage, representing a displacement of the ferromagnetic member in response to a change in the hydraulic pressure, is determined and provided in the form of an analog voltage or a digital code.

Abstract: A pressure sensor comprising a pressure-displacement translating mechanism including a movable body driven by a hydraulic pressure and a spring for urging the movable body in a direction opposite the pressure, and a displacement-pulse phase conversion unit including a permanent magnet secured to the movable body and a magnetically soft member carrying an electrical coil thereon and disposed at a stationary point adjacent to the region of movement of the permanent magnet. A pulse voltage is applied to one end of the electrical coil, the other end of which is connected in series with a resistor. A voltage drop across the resistor is detected, and a time lag of the voltage drop with respect to the pulse voltage, representing a measure of hydraulic pressure, is provided in the form of an analog voltage or a digital code.

Abstract: A pressure sensor comprising a pressure-stress conversion mechanism including a movable body which is driven by a hydraulic pressure to be determined; a spring means which urges the movable body in a direction to oppose the pressure applied; a stress-pulse phase conversion unit connected to the movable body for producing a stress in accordance with the magnitude of the pressure in response to a load applied by the movable body and including a member of an amorphous, magnetically soft metal material having an electrical coil disposed thereon. A pulse voltage is applied to one end of the electrical coil, the other end of which is connected in series with a resistor in order to detect a voltage drop across the latter. The time delay of the voltage drop with respect to the pulse voltage, which depends on the magnitude of the hydraulic pressure, is indicated in the form of an analog voltage or a digital code.

Abstract: An electromechanical transducer for transforming pressure fluctuations into varying electrical signals, especially for use as the induction tube pressure sensor for an internal combustion engine. A Hall-effect sensor moves within a local magnetic field to detect changes in pressure which alter the configuration of a diaphragm or diaphragm bellows to which the Hall-generator is attached. In order to suppress temperature-dependent terms in the Hall voltage equation, the invention provides for periodically alternating energization of the electromagnets, i.e., for alternation or alternating shut-off of the magnetic field. The Hall voltages measured during the two states of the magnetic field are subtracted from one another, thereby eliminating the temperature-dependent term. A number of configurations of the transducer elements is presented.

Abstract: Liquid flow sensing apparatus which in the illustrative embodiment is used to sense an occluded vein (cessation of blood flow). A flexible pressure pillow is connected in the blood flow line and is inserted into a housing in contact with a metallic leaf spring. The position of the leaf spring is adjusted relative to an eddy current proximity sensor so that the sensing apparatus is calibrated to a no-alarm position during proper blood flow. If blood flow ceases, the flexible pressure pillow contracts thereby moving the leaf spring away from the eddy current proximity sensor and an alarm condition is thereby detected.

Abstract: A pressure or force transducer capable of miniaturization. Preferably, the transducer takes the form of a "contact lens" and is applied to the eyeball to permit intra-ocular pressure to be measured.

Abstract: A pressure responsive control device having a housing carrying a flexible diaphragm therein that cooperates with the housing to define a pressure chamber therein that is adapted to receive a variable pressure that acts against the diaphragm to position the diaphragm relative to the housing in relation to the value of the pressure, the diaphragm being operatively interconnected to a plunger that follows movement of the diaphragm. The control device has a transducer operatively associated with the plunger to produce an electrical signal in relation to the position of the plunger, the transducer comprising a core carried by the plunger in axially aligned relation therewith and an induction coil carried by the control device and receiving the core therein. A range spring is carried by the housing and is operatively interconnected to the diaphragm to tend to oppose movement of the diaphragm in one direction of movement thereof.

Abstract: A system including a sensor and electronic instrumentation for measuring fission gas pressures inside a pressurized system or device or the like, such as a nuclear fuel rod. The system is based primarily on what is commonly known as the Villari effect which is the dependence of the magnetic permeability of certain magnetic materials upon applied stress, and permits pressure measurements to be made without any mechanical or physical penetration of the fuel cladding or end cap of the fuel rod. In a preferred embodiment pressure sensing is implemented by locating a sensor made from Villari sensitive material inside the pressurized system. The pressure places a stress loading on the sensor which in turn produces electrical output signals proportional to the applied stress.

Abstract: A digital pressure sensor for measuring fluid pressures at relatively high temperatures includes an electrically conducting fiber coupled to the fluid by a force disc that causes tension in the fiber to be a function of fluid pressure. The tension causes changes in the mechanical resonant frequency of the fiber, which is caused to vibrate in a magnetic field to produce an electrical signal from a positive-feedback amplifier at the resonant frequency. A count of this frequency provides a measure of the fluid pressure.

Abstract: An intracranial pressure transducer includes a casing comprising an annular member having a screwed part on an outer wall thereof for fitting and securing a skull of a body. A pressure-electric transducing portion including a supporting member which is inserted within an inner wall of the casing and is tightly fixed to the predetermined upper portion from a tip portion of the casing, an indicating circuit for indicating the intracranial pressure in response to an output of strain sensitive elements, and indicating means.

Abstract: A pressure transducer comprises a bellows as the pressure sensing element and a variable inductance coil whose inductance is made to vary as a function of pressure sensed by the bellows. Motion is transmitted between the bellows and a plunger associated with the coil by means of a bent lever mechanism. The mechanical advantage of the bent lever is adjustable, after assembly of the transducer, to set the span to a desired value.

Abstract: To measure small displacements, for example displacement of a membrane under change of pneumatic pressure applied at opposite sides thereto, a ferromagnetic wire is stretched between a fixed support and the membrane. An exciter coil, connected to a source of alternating current of suitable strength cyclically reversely magnetizes the ferromagnetic wire. A pick-up coil is electromagnetically coupled to the wire to sense the change of magnetization thereof which will be in the form of sharp needle pulses as the magnetization of the wire changes, the pulse amplitude and pulse width being highly dependent on the strain in the wire and hence on the deflection of the membrane. The wire may be stressed under tension.

Abstract: A first oscillator is associated with a pressure detector so that frequency of an output signal of the first oscillator varies in response to variations of the detected pressure. A second oscillator having a same construction as the first oscillator is provided for determining a sampling period of the output signal of the first oscillator, thereby compensating for variations of the frequency of the output signal derived from the first oscillator due to variations of temperature, humidity, a power supply voltage, etc.

Abstract: A pressure sensor comprising pressure responsive means wherein its location is shifted in response to variations of a pressure to be detected, and frequency variation means for varying an oscillation frequency of an oscillator in response to a shift movement of the pressure responsive means. The pressure responsive means and the frequency variation means are mounted on a single supporting table. The single supporting table shows a thermal expansion substantially identical with the total thermal expansion of the pressure responsive means and the frequency variation means, thereby stabilizing a pressure detection.

Abstract: A pressure detector comprising a spring-loaded diaphragm mounted in a housing to define a pressure chamber to which test fluid is introduced. A pulse generating element is provided to generate an electrical pulse in response to a displacement of the diaphragm when the fluid pressure in the pressure chamber exceeds a predetermined level. An averaging circuit is connected to the pulse generating element to convert the pulses into a signal having a voltage level representative of the mean value of the pressure variation.

Abstract: A mechanical and electrical pressure sensor wherein the mechanical part includes a fluid pressure chamber with a magnetic, electrically conductive diaphragm moving out-of-contact with a stationary contact in the presence of pressure and into contact therewith in the absence of pressure or because of energizing of a cooperatively acting magnetic coil. The electrical circuit connected to the coil includes a clocked flip-flop, the output of which is high during a time interval when the contacts are open (coil energized) and which is low when the contacts are closed (coil deenergized). The duty cycle of energized time to total time is a measure of average coil winding current, and, hence, sensed pressure. The ratio of energized intervals to total intervals develops a useful digital measurement of pressure readily useful in a computer.

Abstract: A pressure pickup for measuring the pressure in the intake manifold of an internal combustion engine. The pressure pickup comprises a part, movable in response to the manifold pressure, to which is coupled means for short-circuiting the magnetic flux lines of an electromagnet so that the change in flux lines is detected by the electromagnetic coil and measured by an induction evaluation circuit and thus indirectly measuring the manifold pressure.

Abstract: A pressure transducer comprises a series-connected helical coil spring and bellows assembled into the bore of a housing by anchoring the spring and bellows at locations which place them in a state of tension. Expansion and contraction of the bellows reacts against the spring and correspondingly positions a ferrite slug within an inductance coil to cause the inductance thereof to be a function of the pressure differential acting on the bellows. One end of the coil spring is threaded onto a threaded fitting secured to one end of the bellows, and slope calibration of the transducer is accomplished by setting the amount of engagement of the spring with the threaded fitting. Offset calibration can be performed by either of two disclosed techniques, and the offset and slope calibrations can be independently made.

Abstract: In a pressure transducer of the type utilizing movement of a pressure responsive member to move the core of a differential transformer which is excited periodically by an oscillation circuit and produces a.c. voltages converted into a d.c. output voltage by an AC-DC conversion circuit, a calibration circuit which produces a variable calibrating voltage is provided. Calibrating the output voltage of the pressure transducer to a reference value at a reference pressure is attained by two sequential steps. In the first step, relative position between the core and the windings of the differential transformer is determined, with the reference pressure exerting on the pressure responsive member and with the calibration circuit being disconnected from the conversion circuit, so that the d.c. output voltage deviates from the reference value. In the second step, the calibration circuit is connected to the conversion circuit and the calibrating voltage is varied so that the d.c.

Abstract: The invention relates to interrogation, detection, and monitoring apparatus useful for monitoring changes in the resonant frequency of a passive L-C circuit implanted in the cranium, the resonant frequency of the implanted circuit varying in a predetermined fashion with changes in the intracranial pressure. The present invention is disposed externally of the skull and provides apparatus for imposing electro-magnetic radiation on the implanted circuit, the frequency at which the radiation is absorbed being then detected and converted into an indication of intracranial pressure.

Abstract: An air pressure monitor includes an electro-mechanical sensor comprising a flexible diaphragm whose deflection is proportional to the air pressure applied thereto, and a variable inductor including a coil and a movable core inside of the coil, the movable core being attached to the flexible diaphragm for movement in response to the deflection thereof to adjust the inductance of the coil in proportion to the air pressure applied to the diaphragm. The monitor further comprises electrical circuits including a first oscillator circuit including the coil for producing a pressure signal at a frequency proportional to the pressure in response to the inductance of the coil, and a second oscillator circuit for producing a reference signal at a frequency corresponding to the frequency produced by the first oscillator when the pressure is substantially zero.

Abstract: A fluid pressure responsive transducer is disclosed of the kind having a thin flat vibrating diaphragm serving as a wall of a continuous pressure chamber for converting a variable fluid pressure magnitude directly into a variable frequency electrical signal. The thin flat diaphragm, secured only at its periphery to the chamber, becomes progressively stiffer as it is progressively deformed by fluid pressure loading more and more from its flat or unstressed position. A dual cavity configuration of the pressure chamber is formed by a rigid divider wall with a restricted passage therethrough. The effects of disturbing acoustic waves which might otherwise be generated interior of the fluid chamber or within pneumatic lines coupled thereto are thus suppressed.