Abstract: Where airflow through a system is subject to forward and reverse flow, the mass airflow rate is determined by providing two flow branches A and B meeting at a junction wherein the two branches carry different proportions of airflow in the forward and reverse directions and branch B carries a greater fraction of the airflow during reverse flow than during forward flow. An airflow sensor in each branch measures the airflow irrespective of flow direction to obtain mass flow rate signals R.sub.A and R.sub.B for branches A and B, respectively. The mass airflow rate m is calculated from the equation m=K.sub.A R.sub.A -K.sub.B R.sub.B where m, K.sub.A and K.sub.B are constants for a given apparatus which are determined by each sensor characteristic and the flow characteristics of the junction. The resultant mass flow rate signal m will have a positive or negative sign indicative of forward or reverse flow.

Abstract: This invention comprises a vibration sensor for detecting engine knock. The sensor has a tuning mechanism which is mechanically resonant with a preselected vibrational frequency. The resonating movements of this tuning mechanism are adapted to apply varying stress to an associated magnetostrictive element. A magnetic biasing element imparts a magnetization to the magnetostrictive element and a detecting means is associated with the magnetostrictive element for detecting changes in the magnetization caused by the varying applied stress.

Abstract: Apparatus is disclosed for determining the degree of stiffness of a sheet, for example a banknote, the stiffness being indicative of the condition of the banknote. The banknote (4) is drawn around a bobbin-shaped drum (1) by means of a pair of belts (2, 3) which grip a central portion of the banknote. The inner belt (2) drives or is driven by the central portion of the drum (1). The concave shape of the drum (1) imparts a curvature to the banknote in an axial plane, while the banknote is simultaneously curved in an orthogonal plane as it is wrapped around the drum. As the banknote passes around the drum it emits an audible noise which is picked up by a microphone (5). The amplitude of the microphone signal (7) is proportional to the crispness of the banknote and is indicative of the age of the banknote.

Abstract: A low-cost, two-axis acceleration sensor utilizing piezoelectric generator elements affixed to the rotating housing of an inside-out synchronous motor. Signals generated by the piezoelectric bender elements are amplified, compensated, balanced, and converted to FM signals for transmission off the rotating assembly.

Abstract: An apparatus for accurately centering a wheel on the spindle of a balancer is disclosed. The apparatus has mounting pins resiliently disposed in recesses in the surface of a disk member. The mounting pins have locations that correspond to the mounting holes in a wheel, and engage the mounting holes in the wheel when a means for securing retains the wheel against a planar surface of the disk member.

Abstract: A miniature rate-integrating gyroscope is shown to comprise: an electrical motor (whose rotor, when rotating, constitutes a gyroscopic mass) mounted in a single degree of motion gimbal within a cylindrical case; a motion sensor to determine any rotation of such gimbal with respect to such case, such sensor including a transformer having a primary winding and a secondary winding movable with respect to each other so that the phase difference between alternating signals in the primary and secondary windings is analogous to such rotation; phase detecting circuitry to produce a control signal representative of such phase difference; a torque generator responsive to the control signal to null any rotation of such gimbal; and a fluid damper to critically damp any rotation of such gimbal.

Abstract: A force measuring system is provided in which a force sensitive element (51) includes a movable capacitor plate (21) located between two fixed capacitor plates (19, 20). A pair of jewel bearings (52) are mounted to a support casting (55) and provides support for a force sensitive element (51). The support casting (55) also serves as a support for a hybrid integrated circuit (68) which, in turn, forms a support substrate for one of the fixed plates (19). A second fixed plate (20) may be mounted on the casting (55) via a substrate (69). The hybrid integrated circuit (68) is therefore in close proximity to a capacitor element (19-21). The hybrid circuit (68) provides output power to a torquer coil (37) which centers the force sensitive element (51), with current provided to the torquer coil (37) being indicative of force exerted on the force sensitive element (51).

Abstract: An ultrasonic transducer is improved, particularly for use in perivascular blood flow measurement, by the provision of a coupling member made of a hydrogel. The hydrogel is suitably acrylic based; has a water content in the range from 75 to 90% by weight and preferably about 85%; and has acoustic attenuation of less than 2 dBcm.sup.-1 at 5 MHz, with longitudinal velocity of sound and acoustic impedance of similar order to those for tissue. The crystals of the transducer are preferably sealed from the coupling member by a water resistant coating, the member suitably has an exposed face of part cylindrical shape to accommodate a vascular vessel, and the member is preferably releasably mounted to allow size interchange for different vessels.

Abstract: This invention is an on-board electro-mechanical system designed to detect and indicate abnormal or defective conditions in any or all wheels of a car while it is in motion at highway speed.Each wheel of the car has a vibration sensor to detect abnormal vibration and send a signal to a defect indicator panel. The defect indicator panel of four lights visible to the driver is that unit of the system which warns the driver that a potentially hazardous condition exists, thus minimizing the liklihood of an accident resulting from the condition if the warning is heeded.

Abstract: A method and apparatus for determining and indexing the angular location of unbalance of a rotatable body. Such unbalance is determined by mounting the body on a balancing machine and rotating the body to obtain an unbalance measurement. The method and apparatus provide for the subsequent rotation of the body to a correction position over the shortest possible distance.

Abstract: A multifunction sensor provides two axes of angular rate and two axes of ear acceleration information from a single instrument. The multifunction sensor utilizes an air bearing rotor to support the spinning transducers. Angular rate measurements are made by utilizing two thin film transistors mounted on the rotor and oriented to sense strain about axes in a first plane orthogonal to the rotor spin axis. The two transducers output signals are summed to provide common mode rejection. A second set of thin film transistors are mounted on the rotor in a second plane orthogonal to that of the first set of transistors and oriented to sense strain along the axes orthogonal to the rotor spin axis. Two axes of acceleration can be measured by integrating this output signal at the proper time using a clock frequency. Angular rate and linear acceleration signals may be extracted from the rotating member via slip ring contacts or inductive pickoffs.

Abstract: The transmitter comprises an array of electro-acoustic transducers (1), each of which is connected to an oscillator circuit (9) which has a start input (11). The start inputs (11) successively receive start signals from a start signal generator (13) which comprises a number of comparators (15), each of which comprises a first input (17) and a second input (19). The first inputs (17) are together connected to an output of a sawtooth generator (21), the second input (19) of each comparator (15) are connected to a direct voltage source (23). A direct voltage source (23) is provided for each start signal to be successively generated at least some of the direct voltage sources being controllable in common.

Abstract: A process and a device for the nondestructive ultrasonic testing of the material of generator rotor teeth providing with an inserted slot wedge, using a probe arrangement including transmit probes, reference probes and defect detection probes which are disposed on a support plate in such a manner as to be movably attached to the teeth, wherein ultrasonic beams are transmitted and reflected by the rotor teeth flanks and the reflected beams are received in a reference probe utilizing a two-fold deflection of the sound at the tooth flanks which are inclined with respect to the tooth back. An ultrasonic beam, reflected by any existing defects of a given type and orientation, is selectively received outside the receiving range of the normally reflected acoustic beam by means of a defect detection probe, and the damaged locations is detected by comparison of the ultrasonic signals received by the reference and defect detection probes.

Abstract: A dynamic electric wheel balancer for measuring the imbalance condition in a vehicle wheel and indicating the position and correction weights required for balancing the wheel in one or two planes. The wheel balancer contains a rotating shaft in order to make the dynamic measurements. The shaft is freewheeling during measurement and is brought up to a predetermined minimum r.p.m. value through a motor and clutch arrangement. In order to take the measurements, piezoelectric sensors are used to measure the vertical force components exhibited by the imbalance condition of the vehicle wheel secured to the rotating main shaft. The measured force components are converted into digital form through the use of a voltage controlled oscillator and a counter in conjunction with a timing wheel.

Abstract: Method of non-destructively determining response pressure of a reversible rupture disc which includes: measuring resonance frequencies of lower vibration modes of the reversible rupture disc at varying measuring pressures below the response pressure of the reversible rupture disc; and extrapolating from the resonance frequencies of each of the vibration modes as a function of the measuring pressure, that pressure at which the resonance frequency of the respective vibration mode becomes zero, the lowest pressure at which one of the vibration modes would have zero resonance frequency being the lowest response pressure of the reversible rupture disc; and apparatus for performing the method.

Abstract: An engine knocking detection method and apparatus which can accurately separate engine knocking vibration signals from background noise signals on the basis of the waveforms of the detected engine vibration signals. Usually, engine knocking vibration signals have frequency components of from 6 to 9 KHz and envelope time constants of from 1.5 to 50 ms. Therefore, the engine knocking detection apparatus according to the present invention comprises a band-pass filter (6-9 KHz), a first smoothing circuit which outputs only engine vibration signals with envelope time constants of 1.5 ms or more and a second smoothing circuit which outputs only background noise signals with time constants of 50 ms or more, in addition to a vibration sensor, amplifiers, a rectifier, and a comparator.

Abstract: A probe for obtaining information about a fluid comprising an electrically-shielded transducer having a lens for focusing energy waves, the transducer being attached to a cable and mounted in a protective sheath supported by a rod, whereby the transducer can be immersed in the fluid and moved around therein to take readings at various locations.

Abstract: An imbalance detector for a centrifuge includes a pendulum arm that is tuned to a critical frequency that lies within a predetermined range of the critical frequency of the rotor of the centrifuge. An imbalance force imposed by the rotor is transmitted to the detector and if the imbalance force exceeds a predetermined threshold the arm contacts an electrical contact to generate an appropriate electrical signal.

Abstract: A vibration diagnosis method and apparatus for rotary machines adapted for measuring the vibration of rotor shaft of a rotary machine, extracting the vibration component synchronous with the revolution of the rotor shaft from the measured vibration data, comparing the amplitude of the extracted vibration component with the amplitude of the overall vibration, analyzing the causes of the synchronous vibration component when the result of the comparison meets a predetermined reference, judging, in accordance with the result of the analysis, whether the vibration due to mass unbalance is attributable to an abrupt generation of mass unbalance or to a thermal bow of the rotor shaft, and displaying the result of the judgment. The analysis of the vibration component is made in real time or making use of data stored in the past.

Abstract: A method of sensing a knocking taking place in an internal combustion engine through the sensing of pulsative component of the cooling water pressure or lubricating oil pressure. The sensing of the pulsative component is made by removing the static component from the composite pressure which is the sum of the pulsative component and the static component. An apparatus for sensing a knocking taking place in an internal combustion engine has a differential pressure sensing mechanism including a pressure sensing diaphragm and a pulsation absorption mechanism. The pressure sensing diaphragm receives at its one side the composite cooling water pressure or composite lubricating oil pressure which is the sum of the pulsative component and static component. The pulsation absorption mechanism absorbs the pulsative component from the composite pressure so as to transmit only the static component of the pressure to the other side of the pressure sensing diaphragm.