Abstract: A magnetoresistive sensor for use in detecting relative motion between the sensor and a further object bearing an alternating pattern of north/south magnetic poles. The sensor includes one or more pairs of magnetoresistive elements positioned so that each element within a pair magnetically complements the corresponding element in that pair. That is, whenever an element is exposed to a north pole of the magnetic pattern, a corresponding complementary element is exposed to a south pole so as to provide a magnetically complemented output. Such pair of complementary magnetoresistive elements are connected into a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled. The quadrature sensor output is frequency multiplied to provide frequency multiplied output signals in quadrature.

Abstract: A magnetoresistive sensor for use in a rotary encoder with a drum having a circumference covered with a magnetic track at a predetermined pitch includes a plurality of magnetoresistive elements positioned opposite the drum and connected in a bridge circuit such that when the drum rotates an output signal from the bridge indicates a rotary angle of the drum. The magnetoresistive elements include one or more complementary pairs of elements positioned 180° out of phase. Each of such pair of complementary magnetoresistive elements is connected in one leg of a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled. Magnetoresistive sensor element configurations for minimizing the impact of temperature gradients across the magnetoresistive sensor are also disclosed.

Abstract: A device for locking a disk or plate to a shaft, wherein the disk or plate has an opening therein corresponding substantially to the diameter of the shaft; the device comprising:a) a threaded bolt having an enlarged head;b) a wedge piece having a round outer surface interrupted by a tapered flat surface on one side thereof; the wedge piece having a throughbore through which the bolt is passed; andc) a nut for threaded engagement on the threaded bolt downstream of the wedge piece, the nut being bonded to the threaded shank adjacent the wedge piece.

Abstract: A rotary pulse generator kit for monitoring the rotation of a shaft includes an enclosure capable of accepting two different sensor modules. Each sensor module may include axially aligned magneto-resistive sensing elements that sense magnetic poles imprinted in a pattern on a rotor that rotates with the shaft. Two sensor modules having different incremental pulse output rates may be supplied with the tachometer kit. In this way, the shaft may be monitored by a pair of sensor modules pre-set at different incremental pulse output rates, mounted to the same enclosure.

Abstract: A magnetoresistive sensor for use in a rotary encoder having a drum having a circumference covered with a magnetic track at a predetermined pitch includes a plurality of magnetoresistive elements positioned opposite the drum and connected in a bridge circuit such that when the drum rotates an output signal from the bridge indicates a rotary angle of the drum. The magnetoresistive elements include one or more complementary pairs of elements positioned 180.degree. out of phase. Each of such pair of complementary magnetoresistive elements is connected in one leg of a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled.

Abstract: A tachometer for monitoring the rotation of an output shaft (e.g. of a motor, where the motor is enclosed within a standard NEMA housing), includes an enclosure (e.g. adapted to be secured to an end plate of the motor housing), the enclosure having a radial center and a longitudinal axis which, when the enclosure is secured to the housing, are aligned with a longitudinal axis of the output shaft. The enclosure has at least one mounting surface in a peripheral wall portion thereof, the mounting surface having an aperture formed therein which opens in a radial direction. A sensor module including a pair of axially aligned magneto-resistive sensors is mountable on the mounting surface of the enclosure such that the module protrudes through the aperture with the sensors facing radially inwardly.

Abstract: Load shift compensation of a strain gage load cell is accomplished by connecting a pair of fixed resistors in series across the output of a bridge circuit incorporating the load cell strain gages. The junction point between the series resistors is established at a desired signal level by a digital to analog converter connected thereto or by a voltage divider network so that, in effect, a part of the resistance of the resistors required to achieve load shift compensation is made to shunt a pair of the strain gages in the bridge circuit. The required signal level may be established by positioning weights on the scale platter at different positions parallel to the longitudinal axis of the load cell beam and adjusting the signal level at the junction point between the shunting resistors until a desired degree of compensation is achieved. The digital correction value required at the input of the digital to analog converter to achieve compensation is stored in the memory of the scale computer.

Abstract: A weighing apparatus employing dual load cells or dual load cell sets is provided with a hinged weigh frame attachment to transmit only vertical load to one load cell or set of load cells and prevent transmission of moments about the longitudinal axis. A ball and dual cup arrangement is connected between the weigh frame and the other load cell or set of load cells to transmit vertical load but prevent the transmission of moments about either the longitudinal or transverse axes of the load cell. Because of the decoupling arrangements, the weighing apparatus requires only longitudinal shift adjustment for only the load cell(s) connected to the hinge.

Abstract: A tachometer assembly for monitoring the rotation of an output shaft for measuring the rotational velocity and position of rotating shafts, and more specifically, to a magneto-resistive tachometer assembly which incorporates a dual purpose cover which, during normal use, fits over the tachometer drum and electronic sensor package to give physical protection to the unit. In a shipping mode, however, the cover is reversed and performs the function of an alignment tool in that a radial gap between the magnetic drum and magneto-resistive sensor may be preset at the factory during assembly of the unit. Reversal of the cover to its normal in use position is done in such a way that the preset radial gap is undisturbed.

Abstract: A digital scale is compensated for hysteresis by characterizing an envelope pattern of increasing and decreasing linearity attributes thereof defining the limits of hysteresis error. Polynomial expressions define this envelope pattern and a correction procedure is developed which is based upon offsets from the envelope pattern as well as the merging characteristics of deviations evidenced from complex loading histories. The latter historical data are used to identify loading progression transitions necessary for the generation of correction values.

Abstract: A tachometer for monitoring the rotation of an output shaft (e.g. of a motor, where the motor is enclosed within a standard NEMA housing), includes an enclosure (e.g. adapted to be secured to an end plate of the motor housing), the enclosure having a radial center and a longitudinal axis which, when the enclosure is secured to the housing, are aligned with a longitudinal axis of the output shaft. The enclosure has at least one mounting surface in a peripheral wall portion thereof, the mounting surface having an aperture formed therein which opens in a radial direction. A sensor module including a pair of axially aligned magneto-resistive sensors is mountable on the mounting surface of the enclosure such that the module protrudes through the aperture with the sensors facing radially inwardly.

Abstract: A digital load cell includes a rocker pin, guided beam torsion ring or other counterforce, a circuit board mounted on the counterforce and an enclosure sealing the circuit board and all but the load bearing surfaces of the counterforce. The circuit board includes an A/D converter and a micrcomputer. Digital communication is provided with the circuit board through a connector mounted on the enclosure. Weight data are corrected digitally. The load cell may be calibrated, characterized, controlled and monitored digitally through the connector from a remote location without physically penetrating the enclosure. One or a number of digital load cells may be connected to a computer or controller to form one or more weighing scales.

Abstract: A digital load cell includes a rocker pin, guided beam, torsion ring or other counterforce, a circuit board mounted on the counterforce and an enclosure sealing the circuit board and all but the load bearing surfaces of the counterforce. The circuit board includes an A/D converter and a microcomputer. Digital communication is provided with the circuit board through a connector mounted on the enclosure. Weight data are corrected digitally. The load cell may be calibrated, characterized, controlled and monitored without physically penetrating the enclosure. One or a number of digital load cells may be connected to a computer or controller to form one or more weighing scales.

Abstract: Multiple digital load cells forming one or more weighing scales are connected together and to a common master controller in a local area network. The digital load cells are polled by and provide weight readings to the master controller. The weight readings are combined with a load position correction factor for each load cell and summed to provide a weight indication corrected for load position. The values of the load position correction factors are determined during set up of the scale and stored at the master controller. An individual load cell can be diagnosed remotely and replaced if defective. A new load position correction factor is determined and stored for a replacement load cell.

Abstract: A digital weighing scale is compensated for the effects of off-center loading by determining the position of the load and calculating a corrected weight value according to such position. Position sensing transducers are mounted on the load cell to provide information regarding the position of the load on the weighing scale. An expression for corrected weight as a function of load position and magnitude is determined for the particular scale and stored. The expression is used to calculate corrected weight according to the magnitude and position of each weight placed on the scale. The load cell may include a counterforce of substantially any type including single bending beam, dual bending beam or capacitive structure, and the load magnitude and position sensors may be of substantially any type including strain gages and capacitive sensors.

Abstract: A digital scale compensated for creep by first obtaining and storing a mathematical representation of creep as a function of time for the particular scale. The current "creep state" of the scale is continually calculated, stored and used to correct the current weight indication for creep. The current creep state is obtained by calculating the increment of creep since the previous determination of creep state and combining it with the stored previous creep state.

Abstract: Load cells incorporating one or more gaged beams as the load sensing elements are compensated for off-center loading in the longitudinal and/or lateral directions. The load cell may also include one or more flexure arms extending parallel to the beam. The relative position of the gages and the neutral axis of the beam is made such that the gages produce a correctible response to off-set loading by positioning the gages and/or physically altering the beam. Preferably, conventional or special strain gages are mounted upon the beam(s) to produce a correctible response by the gages by rotating and/or displacing them with respect to the longitudinal axis of the beam. Resistors are then connected to certain of the strain gages to compensate for off-center loading. The strain gages are advantageously placed all on one side of a beam but may be placed on opposite sides thereof.

Abstract: A scale plate with one or more load cell structures formed integrally therewith. Each load cell includes a flexure beam with strain sensing means mounted thereon and a fixed end merging with the plate. A support member has a free end and another end that is fixed to and merges with the other end of the beam. The load is applied between the plate and the support member. The support member permits the point of load application to be selected for improved output response of the load cell. A second flexure beam may be provided to counter any torsion effects on the first mentioned beam. The beam and support member are formed by cutting slots in the scale plate.

Abstract: This invention relates to new and improved single beam load cells which are compensated for both longitudinal and lateral displacement of the load; to new and improved scale arrangements incorporating such load cells; and to methods of compensating such single beam load cells. In one embodiment of the invention strain gages are attached to only one side of the beam and the beam is honed or filed to compensate for both longitudinal and lateral displacement of the load. In another embodiment of the invention strain gages are placed on both sides of the single beam and the strain gages are placed on the beam at a slight angle from the longitudinal axis of the beam. In this embodiment the beam may be honed to compensate for both lateral and longitudinal displacement of the load.

Abstract: A force measuring device comprising a load receiving platform supported by a multiple bending parallelogram beam type load cell is provided with a plurality of electrical strain gages. Strain gage elements mounted on one of the beams are displaced toward one side of the beam and strain gage elements mounted on the other beam are displaced toward the other side of the other beam. An appropriate resistor network is connected to at least one strain gage on one or both of the beams to correct for either longitudinal or transverse displacement of the load on the platform. To correct for both transverse and longitudinal displacement of the load a resistor network is connected to each of three of the strain gages. Suitable procedures for determining the values of the resistor networks in combination with the above structure are included.