Lake Shore Cryotronics, Inc.

Reliance Electric Company

Mettler-toledo Gmbh

Toledo Scale Corporation

Northstar Technologies Inc.

Neil C Griffen

Richard S Stokes

Joseph F Bioty

Benny N Dillon

Mark E Weihs

Mark Ayzenberg

James F Million

Kenneth L Dickinson

Richard C Loshbough

Stephen A Patoray

Kenneth Dickinson

Mark Azyenberg

David M Behrman

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. The sensing arrangement can be used, for example, in the context of a rotary encoder having a drum having a circumference covered with a magnetic track at a predetermined pitch, and may include 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 encoder indicates rotary motion of the drum.

Magnetoresistive sensor with reduced output signal jitter

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&deg; 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.

Magnetoresistive sensor with reduced output signal jitter and temperature compensation

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:

Taper shaft lock

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.

Magneto-resistive tachometer kit including two sensor modules providing

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.

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. An annular drum having a pair of magnetic patterns arranged on a peripheral end surface thereof is operatively fixed on the motor output shaft via a hub member such that the magnetic patterns on the drum are automatically aligned with the sensors and radially spaced therefrom by a predetermined radial gap when the drum is fixed to the output shaft and the enclosure is mounted on the end plate in an operatively assembled relationship.

Magneto-resistive tachometer sensor module with different resolution

A magneto-resistive tachometer includes an enclosure having a thickness of about 3/4', formed with a central through opening therein and a plurality of bolt holes sized and located for alignment with bolt holes on a standard NEMA C-type motor end face. The enclosure has a recess formed adjacent the central through opening and adapted to receive a sensor electronics package, and a radial slot formed between the central through opening and the recess for receiving a sensing element. An associated sensor drum has a peripheral surface with encoded sensor patterns thereon adapted to be sensed by the sensing element, and a center hub connected to the peripheral surface by a plurality of spokes. The center hub is adapted for clamping engagement with the output shaft of the motor within the center opening of the enclosure, in radially adjacent position relative to the sensing element. At least one of the spokes is provided with shaft clamping means for securing the drum to the output shaft of the motor.

Slim profile digital tachometer including planar block and rotor having

In a tachometer assembly for attachment to an output shaft of a rotary machine, wherein the tachometer assembly includes a tachometer housing enclosing a sensor drum fixed to a tachometer shaft, the shaft extending from the tachometer housing and adapted for attachment to the output shaft of the rotary machine for rotation therewith, and a sensor pad located peripherally adjacent the sensor drum, an improvement which includes an internal wrench mechanism for locking the tachometer shaft to the tachometer housing for common rotation therewith so as to facilitate threaded engagement between the tachometer shaft and the output shaft, as well as for unlocking the tachometer shaft from the tachometer housing for rotation relative to the tachometer housing to thereby permit the tachometer shaft to rotate with the output shaft after the tachometer housing is secured to the rotary machine housing.

Tachometer assembly with integral internal wrench

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.

Load shift compensation for weighing apparatus

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.

Multiple load cell weighing apparatus

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.

Magneto-resistive tachometer assembly with reversible cover and related

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.

Hysteresis-compensated weighing apparatus and method

Self-aligning tachometer with interchangeable elements for different

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.

Load cell

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.

Growing community of inventors

Westerville, OH, United States of America

Neil C Griffen