Abstract: A SAW sensor arrangement includes a transducer including a support for supporting a SAW device. The support includes a sensor location part located between two oppositely extending attachment parts. The SAW device is mountable to the sensor location part. The sensor arrangement 10 includes at least two spaced friction raisers. The sensor arrangement includes a clamp arrangement which applies a clamping force to clamp the sensor arrangement to an item. The sensor arrangement is arranged so that in use each of the friction raisers is located between a different one of the attachment parts and the item.

Abstract: A torque measurement flexplate (20) includes a substantially planar body (54) which defines a plurality of circumferentially distributed axial through apertures (22), a radial web (24) extending between each pair of adjacent axial apertures (22). The flexplate (20) further defines a plurality of circumferentially distributed axial outer fastening holes (26) for attachment to an output member. The flexplate (20) includes a strain sensor (28) for measuring the shear strain field on the flexplate (20). The flexplate (20) defines a recess (30) in which the strain sensor (28) is located, the recess (30) being defined in an axial surface (32) of one of the radial webs (24) such that, in use, the sensor (28) lies at least proximate to one of the local neutral axes (34) relating to one of a plurality of unwanted strains (36) to which the flexplate (20) is subject in use.

Abstract: Quartz cuts are provided which exhibit temperature characteristics which are favorable for making differential SAW temperature sensors. Families of Y cuts rotated between 0° and 60° degrees in combination with placement of two resonators at specified angles to each other are disclosed. Further, preferred embodiments in which the resonators are placed on opposite sides of a zero TCF line are disclosed, to provide wide temperature differences while efficiently utilizing the available bandwidth. The design permits placement of the resonator at angles smaller than 12.5° and even less than 5° therebetween, most preferably on quartz rotated Y cut between 28.5° and 42.75°.

Abstract: A measurement device for operating in high voltage electrical fields such in high voltage electrical switchgear, having a sensor and a ?/2 monopole helical antenna coupled thereto. The antenna is coupled to a ground via return stub in lieu of the common ground plane. The antenna is made of wire having a sufficiently large diameter to prevent forming corona discharge point electrode throughout the outer surface of the volume defined by the antenna, thus minimizing corona discharge risk. The antenna further provide relative immunity from induced voltage at the 50-400 Hz range from the high voltage fields, allowing ESD sensitive devices to operate in close proximity to the high voltage conductors.

Abstract: A torque measurement flexplate (20) includes a substantially planar body (54) which defines a plurality of circumferentially distributed axial through apertures (22), a radial web (24) extending between each pair of adjacent axial apertures (22). The flexplate (20) further defines a plurality of circumferentially distributed axial outer fastening holes (26) for attachment to an output member. The flexplate (20) includes a strain sensor (28) for measuring the shear strain field on the flexplate (20). The flexplate (20) defines a recess (30) in which the strain sensor (28) is located, the recess (30) being defined in an axial surface (32) of one of the radial webs (24) such that, in use, the sensor (28) lies at least proximate to one of the local neutral axes (34) relating to one of a plurality of unwanted strains (36) to which the flexplate (20) is subject in use.

Abstract: A method of wirelessly interrogating a sensing device comprising a plurality of passive sensors, to determine a measurement parameter, comprises the steps of repeatedly interrogating the sensing device using a predetermined transmission signal and detecting the response; estimating the measurement parameter for each sensor by means of an analysis of the data accumulated as a result of the interrogation step, and determining the average of the parameters derived from the estimating step for each sensor, using a weighted average, in which the weightings depend on the amplitude of the sensor response. The measurement parameter may be a resonant frequency where the passive sensors are resonant devices, and the sensors may be SAW devices.

Abstract: A combined pressure and temperature sensor comprising a tubular member 3 of circular cross section having a closed end and an open end, the open end, in use, connecting to a pressurized environment such that the interior of the tubular member is exposed to the pressure, a flat or preferably a symmetrical distribution of flats 1 being formed on the outer cylindrical surface of the tubular member 3, and a sensor element 2 mounted on at least one said flat 1, which sensor element 2 is sensitive to the strains in the tubular wall of the tubular member 3 resulting the pressure in the interior thereof and the temperature of said tubular member.

Abstract: A circular shaft having a platform formed on it by machining a circular flat into the surface of the shaft. A channel extends around the periphery of the circular flat with a depth in the range of 10 to 15% of the diameter of the shaft and in the range of 30 to 50% of the width/diameter of the platform. The width of the platform is 4 to 7% of the diameter of the shaft. A sensor is mounted on the platform, whereby the formation of the platform and surrounding channel reduces the strain arising in the device which is transferred to the sensor.

Abstract: A run flat safety band 1 has a wireless sensor 11 incorporated therein, which can be remotely interrogated in order remotely to confirm that the safety band is fitted on a wheel 4. The sensor 11 includes a pressure and temperature sensor, enabling the pressure and temperature within the tire 2 mounted on the wheel 4 to be remotely checked, by means of which remote indication can be provided that the tire 2 has deflated and is running on the runflat band 1 and also that the tire 2 is overheating and likely to break up prematurely while running on the runflat band 1.

Abstract: Aspects of the present invention are directed to using surface acoustic wave (SAW) sensors mounted on a disc coupling component in a powertrain to measure the torque generated by an automobile engine. The sensor may be positioned and oriented on the disc coupling component so that the phase velocities of SAWs propagating through active elements of the SAW sensors are aligned with principal strain components due to torque in the disc coupling component. The torque may be calculated by determining the difference between resonant frequencies of the active elements to suppress common-mode interference factors. In addition, SAW resonant frequencies may be communicated in a non-contacting manner by utilizing rotary and stationary couplers employing radio frequency (RF) signals. Moreover, SAW sensors may be activated and interrogated by employing targeted RF pulses having different carrier frequencies at or near respective resonant frequencies of each resonator in a SAW sensor.

Abstract: A method of calibrating an individual sensor of a particular sensor type whose output varies non-linearly with at least one measured quantity and at least one operating condition. The first step includes producing a set of calibration curves for each sample sensor of the particular sensor type. The resulting sets of calibration curves are then averaged and the results used to produce a generic calibration surface for the particular sensor type showing its variation. Individual calibration measurements are then taken for a number of different values of the measured quantity at a small number of discrete values. The individual calibration readings are then used to map the generic calibration surface to the individual calibration measurements of the individual sensor.

Abstract: A SAW based pressure sensor having a base 2a with an aperture 3 formed therein and a substrate 4 mounted on the base so as to completely overlie the aperture. The substrate 4 is adhered to base 2a so as to form a fluid tight seal around the periphery of the aperture 3. A first SAW resonator 5 is mounted on the substrate 4 wholly within the region overlying the aperture 3, with two further SAW resonators 6, 7 being mounted on the substrate wholly within a region which is stiffened by adhesion to the underlying base 2a , such that the two further SAW resonators 6, 7 are completely decoupled from the strain field arising in the substrate due to deflections thereof.

Abstract: A tire pressure monitoring system (TPMS) sensor assembly 1 has a housing 2, a pressure sensor mounted in the housing 2 and an antenna 3 connected to the sensor and extending exteriorly of the housing 2 for effecting wireless communication between the sensor and a remote module. The antenna 3 is moveable between a folded position in which it extends around at least a part of the housing 2 so as to lie substantially in the plane of the housing 2 and an erect position in which it upstands from the housing 2 so as, in use, to extend into the inflation area formed between a wheel and tire. The antenna 3 is biased towards its erect position, and further includes a releasable restraining strap 7 for restraining the antenna 3 in its folded position.

Abstract: A method of manufacturing a pressure monitoring package comprises the steps of mounting a plurality of resonators onto a substrate 1, mounting the substrate 1 in a package base 11, mechanically constraining the package base 11 within a mechanical preloading jig, and adjusting the preload using the jig whilst measuring the frequency of the SAWs until the required frequency is obtained. A lid 7 is then welded onto the package base 11 using a laser welder, after which the preload frequency of the package 10 is fine tuned by using the laser welder to produce laser marks 21-28, 31-38 on the outside of the package 10.

Abstract: A contactless SAW based torque and temperature sensor includes three SAW resonators 2, 3, 4 mounted on a common substrate 1 made of Y+34° cut of quartz. The first SAW 2 has its principle axis inclined at +45° to the X-axis of the substrate, which, in use, is either aligned with the longitudinal axis of a device whose torque is to be measured or is perpendicular thereto, and the second SAW 3 has its principle axis inclined at 135 degrees to the X-axis of the substrate. The third SAW 4 is positioned with its principle axis inclined at an angle, preferably in the range of 0 to 30 degrees, to the principle axis of both the first 2 and second 3 resonators so that none of the SAWs are parallel, the third SAW 4 enabling temperature measurements to be taken.

Abstract: A rotary coupler comprises a stator 1 having a first face 3a and a rotor 2 having a second face 4a, the first and second faces 3a, 4a being spaced apart from and facing each other. A first electrically conducting track 5 is provided on the first face 3a of the stator 1 which forms a transmission line and has spaced apart ends A, B and a second electrically conducting track 6 is provided on the second surface 4a of the rotor 2 also forming a transmission line and having spaced apart ends C, D. One end A of the first track 5, in use, is connected to signal generating means and the other end B of the first track is connected to earth through a resistor substantially equal to the characteristic impedance of the transmission line. The first track 5 extends along a generally circular arc substantially around the first face 3a of the stator 1, the first track 5 having a length substantially equal to an integer number of wavelengths of the signal produced, in use, by the signal generating means.

Abstract: A SAW based tire pressure sensor assembly comprising a body having a tubular stud 1 formed on an end thereof which is engageable in an inflation tube formed in a tire inflation valve 3 so as to fasten the body to the valve 3. A through passage extends through the stud 1 into said body and is in fluid communication with the atmosphere surrounding the assembly by means of apertures 2 in the sides of the body, thereby providing a fluid coupling between an inflation duct of the inflation valve 3 and the atmosphere surrounding the body. A SAW based pressure sensor is mounted within said body so as to be in fluid communication with the atmosphere surrounding the body, and an antenna 4 is connected to the sensor to enable remote interaction therewith. A grounding plate 5 connected to the antenna is sandwiched between the assembly and has arms which engage against the inner surface of the wheel so as to enhance the sensor antenna earth.

Abstract: A method is provided for measuring torque in a shaft of a drive line including a disc coupling component such as a flexplate 1 or a flanged coupling 13, as well as a drive coupling system for carrying out the method. The disc coupling component 1, 13 is connected between a drive input 4 and a drive output so that all torque transmitted between the input and output passes through said component. The disc coupling component 1, 13 has a radially extending portion, which may include a plurality of spokes 7, to which is attached a SAW based strain sensor which communicates with a stationary coupler 3 fastened to an engine block 5 for wireless transmission of data from the sensor, the strain sensor measuring the strain in the disc coupling component 1, 13 from which the torque carried in the input shaft 4 may be calculated.

Abstract: A split ring coupler comprising a stator ring having at least one split in it such that the stator has at least a first and a second end and a rotor ring having at least one split in it such that the rotor ring has at least a first and a second end, said rotor ring being oriented substantially coaxially with and axially spaced apart from said stator ring. At least one SAW resonator is electrically directly coupled between said first and second ends of the rotor ring in series therewith, neither of said ends of said stator ring being connected to ground.

Abstract: A device for measuring torsional distortion of a body comprises first and second clip portions each having a central part and two legs depending from the central part, each leg having adjacent the free end thereof a groove or projection for engaging a respective projection or groove (14) provided in the body (16) to mount the clip portion the body rotationally fastened therewith. A bridge interconnects the clip portion. The bridge is less stiff than the clip portions whereby relative rotational displacement of the clip portions caused by torsional distortion of the body will cause proportional deflection of the bridge. Means, for example a SAW device (15), are provided for measuring the deflection of the bridge to provide an indication of the torsional distortion which produces the deflection of the bridge. Also (20) for the interior all of a hollow body.