Abstract: A pressure is measured by obtaining a difference between an actual resonance resistance of a tuning fork oscillator subjected to the pressure and a natural resonance resistance of the tuning fork oscillator, and then applying the difference to a predetermined relation to obtain a measurement of the pressure. Variations in the natural resonance resistance of the tuning fork oscillator due to temperature variations of the tuning fork oscillator are compensated for by measuring a resonance frequency of the tuning fork oscillator and then determining the natural resonance resistance of the tuning fork oscillator from the resonance frequency based on a predetermined relation between the resonance frequency and the natural resonance resistance of the tuning fork oscillator. The resonance frequency of the tuning fork oscillator is indicative of the temperature of the tuning fork oscillator.

Abstract: The invention features a melt pressure measurement device for measuring the pressure of a melted substance useful in cooled state for forming solid objects. The device comprises a probe for insertion through an aperture in a wall of a melt-containing vessel, with the probe having a pressure-deflectable end surface for contact with pressurized melt. The probe has pressure-resistant securing means for fixing the probe in the wall with the end surface of the probe exposed for contact with the melt in a non-flow obstructive relationship. A seal surface on the probe between the end of the probe and the securing means provides cooperative sealing action with a mating sealing means associated with the wall to prevent exposure of the melt to the securing means. The probe also has pressure detection means internal of the probe, responsive to deflection of the end surface of the probe, for detecting pressure of the melt.

Abstract: A method of obtaining electrical signals corresponding to the position of a mercury mass movable within a vessel, characterized by the fact that the position of the moving mass within the vessel is detected by means of at least one electromagnetic proximity sensor, specifically an induction proximity sensor, that is a sensor adapted to producing an electrical signal when approached by a metal object or when approaching the same.

Abstract: A load washer comprising a pair of thin metal washers between which a contact sensor is positioned. The contact sensor includes pairs of confronting electrodes at a plurality of spaced zones with a pressure sensitive resistive material between each pair, which, under pressure, provide an indication of the force applied to the load washer.

Abstract: A load cell having a loading flexure defining mounting slots for receiving the ends of a strain sensing beam. The strain sensing beam is an I-shaped member having a tapered width along its length and bearing pairs of strain gauges on the top and bottom sides. The strain sensing beam is mounted in the slots of the loading flexure with an amalgam. The thermal coefficients of expansion of the strain sensing beam, the strain gauges, and the amalgam are all matched to within a factor of 2 to provide an inherently thermally compensated load cell that is easily manufactured and free from hysteresis.

Abstract: A sensor containing at least one piezoelectric transducer element is operated via a common, single signal line in both possible operating modes--first, at low frequencies as a measuring element for a mechanical quantity upon utilization of the direct piezoeffect and, second, at higher frequencies as a piezoelectric resonator upon utilization of the inverse piezoeffect for electrical excitation of mechanical oscillations and of the direct piezoeffect for generating the piezoelectric reaction. A high-frequency signal (u.sup.HF, u.sub.F) that describes the resonant characteristic and a lower-frequency signal (u.sub.NF, u.sub.Q) that describes the mechanical influence are generated from the measured signal on the signal line. The faultless function of the sensor together with the appertaining measuring amplifier, for example, can thus be monitored immediately during a measurement with the sensor or a simultaneous measurement of two different quantities can be undertaken.

Abstract: An overpressure-protected, differential pressure sensor (37) is formed by depositing diaphragm material (24) over a cavity (23) formed and filled with sacrificial material (22) into a front surface of a substrate. The sacrificial material (22) is then removed to create a free diaphragm. The floor of the cavity (23) defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port (33) is created to allow pressure to be applied to the bottom side of the diaphragm (24). An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap (35) to standoffs (34) placed around the top of the diaphragm. The standoffs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A rim gap setting device in a tire uniformity inspecting machine include upper and lower rims for mounting a tire, which are vertically movably fitted on opposed ends of upper and lower spindles, respectively. Upper and lower hydraulically locking devices are provided for locking the upper and lower rims from the inner circumferences thereof, and are mounted around the upper and lower spindles, respectively. Upper and lower hydraulically engaging devices are mounted on the upper and lower spindles and can be radially retreated by being hydraulically interlocked with the upper and lower hydraulically locking devices to be thereby engaged with the upper and lower rims on the locking operation of the upper and lower hydraulically locking devices, respectively.

Abstract: The relative speed of the tires of a vehicle is monitored as an indication of the operating state of the vehicle, wherein if the vehicle is not operating in one of a number of predetermined states, the relative speed is monitored as an indication of relative pressure of the vehicle tires, and further wherein differences in relative speed not related to the predetermined states, and not related to differences in relative pressure, are accounted for.

Abstract: A method and portable microcomputer-based system for determining flow field stagnation points are disclosed. The apparatus uses hot film sensors wrapped around the leading edge of an airfoil to measure boundary layer oscillations. A plurality of sensor signals are provided which may be selected in groups. Signals from sensors in any group are read simultaneously. The signals are then converted to digital form and displayed on the video display of a microcomputer. Points of airflow stagnation are characterized by a doubling in frequency or other discrete harmonics and by a reversing of the phase of oscillations. Those points are identified by displaying and comparing signals from different sensor locations on a video display.

Abstract: A portable basketball rim rebound testing device 10 is illustrated in two preferred embodiments for testing the rebound or energy absorption characteristics of a basketball rim 12 and its accompanying support to determine likely rebound or energy absorption charcteristics of the system. The apparatus 10 includes a depending frame 28 having a C-clamp 36 for releasably rigidly connecting the frame to the basketball rim 12. A glide weight 60 is mounted on a guide rod 52 permitting the weight 60 to be dropped against a calibrated spring 56 held on an abutment surface on the rod to generate for deflecting the basketball rim and then rebounding the weight upwardly. A photosensor 66 is mounted on the depending frame 28 to sense passage of reflective surfaces 75 on the weight to thereby obtain sufficient data to enable a processing means 26 to calculate the rebound velocity and relate it to an energy absorption percentage rate of the rim system 12. A readout is provided to display the energy absorption percentage.

Abstract: A pressure sensor having a ceramic support, a first ceramic layer attached to a peripheral portion of one side of the ceramic support, and a second ceramic layer which is attached to a peripheral portion of another side of the ceramic support such that the pressure sensor is shaped as an integral assembly. The ratio of the thickness of the first ceramic layer to that of the second ceramic layer is in the range of 1:10 to 1:1. The ratio of the thicknesses of the first and second ceramic layers to thickness of the ceramic support is no more than 1:2. The pressure sensor further includes a hollow space formed between the ceramic support and at least one of the first and second ceramic layers so that, after shaping as an integral assembly, the ceramic layer or layers will work as a diaphragm that is capable of deformation under pressure.

Abstract: A pressure sensor comprising a hollow main body (11) defining a bore (14) extending therethrough and having a detection end and an output end. A pressure sensing assembly is disposed within said bore (14) to divide it into a detection cavity (17) and an output cavity (18) through which output signal lines from said pressure sensing assembly extend. A flexible diaphragm (19) is attached to the detection end of the bore to define a sealed detection cavity (17) in which a pressure transmitting liquid is filled. The pressure sensing assembly comprises support plate (24) welded to said main body (11) and supporting a pressure sensing element (26) within said detection cavity (17) through a mounting bed (4). The signal lines sealingly extend through said support plate (24) from said detection cavity (17) to said output cavity (18).

Abstract: According to a capacitive pressure sensor and a method of manufacturing the same, first and second grooves are formed in one and the other surfaces of a substrate, respectively. A sacrificial layer is embedded in the first groove. Insulating films are formed on the substrate, on which the sacrificial layer is formed, to sandwich an electrode. Etching is performed to form a pressure introducing hole through the substrate to reach the sacrificial layer. A hollow portion is formed by removing the sacrificial layer through the pressure introducing hole.

Abstract: The invention is a method for measuring the wavelength of cross-flow vortices of air flow having streamlines of flow traveling across a swept airfoil. The method comprises providing a plurality of hot-film sensors. Each hot-film sensor provides a signal which can be processed, and each hot-film sensor is spaced in a straight-line array such that the distance between successive hot-film sensors is less than the wavelength of the cross-flow vortices being measured. The method further comprises determining the direction of travel of the streamlines across the airfoil and positioning the straight-line array of hot film sensors perpendicular to the direction of travel of the streamlines, such that each sensor has a spanwise location.

Abstract: A pressure sensor Comprising a disk-type base part having a preferably central opening spanned at one end by a surface-type pressure transducer, a pressure receiving part having a diaphragm arranged at distance from the other end side of said opening and integrally formed with a rigid ring having the same peripheral dimensions as the disk-type base part and being connected thereto. A distance holder is provided between the diaphragm and the pressure transducer fully transmitting any deformation of the diaphragm to the pressure transducer. Such a pressure transducer may be manufactured by a simple and cost-effective procedure with the various elements formed of ceramic, sintered and combined.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A pressure sensor assembly is provided containing a substrate having signal conditioning circuitry disposed on both surfaces of the substrate, with the critical pressure sensing element disposed on one surface of the substrate and the laser trimmable resistors disposed on the other surface of the substrate. The preferred ported housing of this invention seals the one side of the substrate containing the pressure sensing element thereby forming a pressurizable chamber, while allowing the signal conditioning circuitry and resistors on the other surface exposed for calibration by laser trimming of the resistors. This eliminates the requirement for a separate housing for the critical pressure sensing element. In addition, when the preferred ported housing is mounted to the pressure sensing side of the substrate for formation of the sealed pressure chamber, the through-holes which electrically interconnect the signal processing circuitry on both sides of the substrate are also concurrently sealed.

Abstract: A microsensor or micromechanical device based upon the piezoelectric properties of thin film lead zirconate titanate (PZT) with a thickness of between 0.1 and 5 microns. The thin film PZT is sandwiched between first and second electrodes which are provided with electrical connection means for electrically connecting the electrodes to a voltage sensor or voltage source. The invention also relates to a method for making such microsensor or micromechanical device.

Abstract: A vortex sensor 14 measures a flow rate of a fluid flowing through a flow passage by detecting alternating pressure variations 26a and 28a generated by a shedding body 16 placed in the flow passage. The vortex sensor 14 includes a sensor housing 32 enclosing piezoelectric sensing elements 62, 64 which are acted on by a movable member 30. The lifetime of the sensing elements in the closed interior is enhanced by providing surface barriers, oxidizing exposed interior surfaces, or providing a gas reservoir. In applications where fluid leakage may be accepted, a controlled leak restrictor provides a limited rate diffusion path to the atmosphere allowing a minimum partial pressure of oxygen to be maintained.