Showing papers on "Inductive sensor published in 1990"

Sensor formed from a deformation heat recoverable material having a predetermined range of temperatures in which recovery occurs and used for measuring a physical characteristic of a system

Abstract: For use in a measuring and analysis instrument, a sensor including a sensor element responsive to changes in a quantity to be measured by the instrument. The sensor element is formed from a deformation heat-recoverable material having a predetermined range of temperatures in which recovery occurs. The sensor may include a control mechanism for maintaining the temperature of the sensor element substantially within the predetermined range. The sensor element forms a part of a circuit including a power source, and the control mechanism may include apparatus for selectively heating the sensor element. The sensor element is operatively connected to a signal device for sensing a physical characteristic of the sensor element and generating signals corresponding to the characteristic sensed. The signal device may include a temperature sensor, a force sensor, or a light sensor. A volt meter or ammeter may be used to measure the level of electrical energy required to maintain the sensor element at a constant temperature, thus serving as an analogue for measuring the temperature directly.

Proximity sensor having a bridge circuit with a voltage controlled resistance

Abstract: Proximity sensors for detecting the presence of metal objects such as sheet metal workpieces within workpiece engaging devices such as grippers and shovels. The proximity sensors are jacketed in a stainless steel casing, making them rugged and resistant to impact damage. Monitor circuits are used with the sensor which enable the devices to sense objects through their metal casing, these objects being disposed upon the sensor casing. A thresholding circuit and a delay circuit are further disclosed and which reduce erroneous indications of the presence of the metal objects upon the sensor. Other embodiments are disclosed which allow for the proper alignment of metallic workpieces within an area and for the determination of the height of a stack of workpieces.

Film canister to facilitate diameter sensing

Abstract: A film canister with non-contacting means for indicating and facilitating sensing and calculation of film roll diameter and length of film left in the canister, and providing indication of film-out. The system for sensing the roll diameter comprises the canister, an inductive sensor and metered feed rollers. The system for calculating the film diameter and length and determining film-out comprises a microprocessor with visual indicating means.

Temperature-stable inductive proximity switch

Abstract: The invention relates to a temperature-stable inductive proximity switch having a transistorized resonant circuit oscillator. The feeding into the emitter-to-collector circuit of the resonant circuit transistor T1 of a balancing current, which depends on the individually determined temperature of the resonant circuit transistor T1 and the individually determined temperature of the resonant circuit coil, ensures that the proximity switch is temperature-stable with respect to its switching distance for every adjusted basic current.

Inductive proximity sensor

Abstract: PURPOSE: To prevent an inaccurate sensing result from being made due to inter nal loss of a resonance circuit. CONSTITUTION: An inductive proximity sensor includes a power supply and a coil 2. The power supply supplies a periodic current to the coil 2, and its conduction time interval is shorter than a feeding time interval. A response of an object to be detected is measured at a time interval, when the current flowing to the coil 2 is essentially zero. COPYRIGHT: (C)1992,JPO

Study of variable inductance transducers as proximity sensors: I. Computer-assisted study

Abstract: The authors are concerned with the computer-aided study of magnetic circuit/coil/target systems for proximity inductive sensors: for this study software for computation of magnetic parameters is used. A specific method for using the software and the results obtained by applying this method to four typical geometries of magnetic circuits are presented. The parameters studied are: the geometry of the magnetic circuit, the geometry and position of the coils, the permeability mu of the magnetic circuits and targets and the saturation of the magnetic circuits.

Oscillator, particularly for an inductive proximity sensor or switch operating without contact

Abstract: In an oscillator, with a resonant circuit (1) having an inductance (L) and a capacitance (Cp) and a positive-feedback transistor (T), the collector-emitter path of which is connected in series with the resonant circuit (1), the positive-feedback transistor (T), which is also used as amplifier transistor, is located between the resonant circuit (1) and a negative-feedback network (2). The series circuit comprising the resonant circuit (1), the positive-feedback transistor (T) and the negative-feedback network (2) is located between the connecting terminals for the operating voltage (UB); the base of the positive-feedback transistor (T) is connected to a direct voltage (Uo) determining the operating point. The oscillator output voltage (UA) is picked up at the series circuit of the collector-emitter path of the positive-feedback transistor (T) and the negative-feedback network (2).

Variable-reluctance inductive sensor

Abstract: The sensor comprises a yoke supporting an electric winding (4) and, coaxially therewith, at least one pole piece (2) and a permanent magnet (3) which are attached to each other According to the invention, the yoke consists of a first (1a) and second (1b) separate parts, the first supporting the winding (4), the pole piece (2) and the magnet (3) in the standard manner, the second consisting of a specific support means for the end of an output electric cable (7, 8) connected to the winding (4), means (19, 20) being provided on these two parts to allow them to be assembled Application to a speed sensor for wheels or a driveshaft, for a motor vehicle

Working cylinder with a sensor for the determination of the position of the piston.

Abstract: In a pneumatic or hydraulic working cylinder (10), an inductive sensor (20) is arranged in one of the cylinder heads (11, 12). The piston (14) has a disc (15) made of electrically conductive material, so that the distance s between the piston (14) and sensor (20) can be continuously determined. Continuous measurement of the motion of the piston (14) is possible because of the damping of the coil of the sensor (20). It is also possible to set specific prescribed threshold values with the aid of setting screws (22) and an evaluation circuit (21). This results in the possibility of particularly simple and exact monitoring of the piston position both at specific points and continuously over the entire working range.

Pressure relief device

Abstract: A pressure relief device having a bursting disc (10) located in an outlet from a vessel or pipe to close the outlet has proximity sensing means (22) positioned adjacent the outlet and actuator means (26 or 28) secured to the surface of the disc facing away from the interior of the pipe and adjacent to the sensing means, the proximity sensing means being adapted to detect the presence of the actuator means The arrangement provides a method of monitoring the rupture of a disc when a predetermined pressure has been reached due to an excessive or dangerous pressure build up in a vessel or pipe Preferably the proximity sensor (22) is an inductive proximity sensor and the actuator means is a metal bracket (26) or a carbon block (28)

Low Cost Binary Proximity Sensor For Automotive Applications

Abstract: A fiber optic binary position sensor has been fabricated simply and inexpensively. This sensor exploits the Faraday Effect to detect the presence of a piece of ferrrous metal The sensor is positioned inside a ring magnet, so that when a ferrous metal object passes close to the face of the magnet, it distorts the field, changing the output of the sensor from low optical power to high. The key component is a piece of bismuth doped iron garnet film with an extremely high Faraday Rotation per unit length and a low saturation magnetization. Material properties of this film will be discussed, along with sensor design and performance. This sensor has many potential applications in the automotive industry, such as monitoring door, hood and trunk positions.

Air drier for vehicle pneumatic system - uses inductive sensor for measuring air humidity at output

Abstract: The drying device has a control circuit using an electronic air humidity sensor (25) coupled to an evaluation stage (28), in turn coupled to a continuous display or an emergency display. The humidity sensor (25) is positioned at the output connection (19) for the air drying device at one side of the flow channel (27) for the discharged air. Pref. the measurement of the humidity level of the discharged air is effected using an inductive method. USE - For providing warning signal for driver when humidity level is above given value.

Method of determining inductivity of an inductive sensor.

Abstract: of EP0358241An electronic circuit measures the distance dependent variation of the inductance of a coil (1) whose core is displaced w.r.t. it. The electronic circuit contains a microcomputer (3) which stimulates the coil with a voltage step. It evaluates the displacement dependent inductance from the resulting charging current using a time measurement . The coil charging current is used to charge up a capacitor (7). The capacitor discharges across a resistor (8) with a time constant large compared to the charging time. The discharge time is evaluated by the microcomputer to produce the distance dependent parameter.

Inductive angular position sensor

Abstract: Inductive sensor for the angular position of a shaft 1 integral with a cylindrical rotor 2 revolving in a stator with wound magnetic circuits 3-4, characterised in that the rotor 2, made in a manner which is known per se of a ferromagnetic material, is associated with means for varying the air gap "e" formed between the rotor 2 and the wound magnetic circuits during rotation of the rotor

Method for the automatic determination of the actual position of an edge or the like in a metallic workpiece surface, in particular a roof channel in a motor-vehicle body, for correcting the movement of an industrial robot

Abstract: The invention relates to a method for the automatic determination of the actual position of a roof channel (2) in a motor-vehicle body (1) in relation to a robot. For this purpose, inductive sensors (4, 5) arranged on the robot tool (6) are used to determine coordinate measuring points at the channel (2) and from these values the position is calculated.

Automatic sensor identification for ultrasonic proximity switches.

Abstract: In the case of ultrasonic proximity switch systems having separate evaluation electronics and varying sensor designs, the evaluation parameters must usually be adapted to the particular sensor type. To avoid errors relating to this, it is advantageous when the system is switched over automatically when a new sensor type is connected. Previously, sensor identification has been realized through manual coding or by coupling different voltage levels to a sensor output signal. The aim is to reduce the susceptibility to faults and the expenditure entailed by this method by applying a plurality of sensors. This is achieved in that the oscillator frequency corresponding to the sensor type is indicated with the help of a counter by means of a pulse-width modulated signal, which corresponds to the pulses of the oscillator frequency that are counted according to the counter content. This counter is advantageously accommodated in an integrated circuit, with which a pulse-width modulated signal is already generated as temperature information.

Device for the non-contact testing of internal threads on workpieces made of an electrically conductive material

Abstract: A device (10) for the non-contact testing of internal threads (11) on workpieces (12) made of an electrically conductive material has a cylindrical sensor body (14) which can be inserted into the internal thread (11) to be tested, and inductive sensor elements (16-19) arranged circumferentially on the free end of the sensor body and operating on the eddy current loss principle. In order to achieve, with a device (10) of this type, in a rapid and simple way, a statement also about the diameter of the internal thread (11) to be tested, in an exact manner, without any potential eccentricity between the sensor body (14) and the internal thread (11) to be tested affecting the measurement, four inductive sensor elements (16-19) arranged distributed uniformly over the circumference of the sensor body (14) are provided. In this case, the sums of the outputs of the pairs of sensor elements (16-19) arranged offset are logically coupled to form an arithmetic mean value.

Electronic calliper gauge

Abstract: The utility model provides an electronic calliper gauge, comprising a fixed gauge head arranged on a main body and a movable gauge head. The electronic calliper gauge is provided with a power supply, a differential inductive sensor, a measuring circuit and a displaying circuit. A parallel spring frame with a stainless steel pipe in the differential inductance sensor is connected with the movable gauge head. A movable magnetic core sheathed on the stainless steel pipe passes through a differential coil and the movable magnetic core is fixed on the parallel spring frame. The measuring circuit is composed of an oscillator directly connected with the differential inductive sensor, a pre-amplifier, a phase-sensitive detector and a direct current amplifier. The utility model has the advantages of compact structure, small size of the measuring circuit, low power consumption, high reading precision and convenient repair and use.

Automatic regulation of oil concentration in refrigerator evaporator - has diaphragm responding to pressure difference to control concentration

Abstract: A chamber (1) contains a refrigerant and the connection for the pressure sensor is provided by a tube (2) carrying a refrigerant/oil mixture. The chamber and tube connects to a diaphragm chamber (6,8). The centre of the diaphragm has a spigot assembly (10) with a central pin, which is axially displaced dependent upon the pressure difference. The free end of the pin operates against a lever (17) that is pivot mounted at one end, with the free end operating a non contact sensor (22), eg., inductive proximity sensor, to provide a regulatory signal.

Device provided with a rotation inductive sensor to control particularly the ignition time of combustion engines

Abstract: Induktiver Drehgeber zur Steuerung des Zundzeitpunkts von Brennkraftmaschinen, mit von einem Dauermagneten durchsetzter Spule und von einer Welle gedrehtem Jochrad, uber dessen Umfang verteilt vorspringende, beabstandete Zahnsegmente an den Magnetpolen zur Spannungsinduktion vorbeibewegt werden, wobei tangential benachbarte Zahnsegmente voneinander unterschiedlich weiten Abstand aufweisen.

Automatic sensor recognition for use in ultrasound proximity

Abstract: In ultrasound proximity switches with a separate electronic evaluation system and different sensor designs, the evaluation parameters normally need to be adapted to the respective sensor type. In order to avoid errors in this respect, it is advantageous if the switchover on connection of a new sensor takes place automatically. Sensor recognition has hitherto been implemented, for example, through manual coding or different voltage levels, which are connected to a sensor output signal. The proneness to interference and the cost of this method when a plurality of sensors are used are to be reduced. To achieve this, the oscillator frequency (2) associated with the sensor type is indicated with the aid of a counter (3) by a pulse-width modulated signal which corresponds to the pulses of the oscillator frequency counted according to the counter reading. This counter (3) is advantageously accommodated on an integrated circuit, with which a pulse-width modulated signal is already generated as temperature information.

Temperature stabilized inductive proximity switch

Abstract: The invention relates to a temperature-stable inductive proximity switch with a transistorized resonant circuit oscillator. By feeding a compensation current in the emitter collector circuit of the oscillator transistor T1, which depends on the individually detected temperature of the resonant circuit transistor T1 and the individually detected temperature of the resonant circuit coil, it is achieved that at each set base current of the proximity switch is temperature-stable in respect of its switching interval.

High pressure proximity sensor

Abstract: A high pressure proximity sensor for high pressure environments uses a balanced bridge variable inductance magnetic core structure to detect the presence of a external ferrous object by a change in inductance. The sensor magnetic flux path is defined by the sensor's specific geometry which includes core windings (20, 22) on the core and sensor housing (2). The core includes centre post (26) of a nonmagnetic material to transfer stress from a housing sensor face to the core's symmetric axis to cancel the effect of an external pressure induced stress on the sensor. The centre post (26) is encircled by an elastomer barrier (28) between the housing sensor face and an adjacent end of the internal core to prevent migration of an internal potting compound between the core end and the sensor face. This structure provides satisfactory sensor operation in environments imposing shock and vibration on the sensor as well as high external pressures.