Abstract: A pressure transducer module includes a plurality of cavities, each cavity in fluid communication with a hydraulic load cell. Each cavity deforms with variations in the pressure of the hydraulic fluid in the cavity. Sensors generate output signals representative of the deformation of the cavities. The sensor output signals are digitized and multiplexed, whereby the transducer module generates a digital output data stream. The pressure transducer module is pre-calibrated for creep, hysteresis, non-linearity and temperature related errors. A computer controller stores the calibration data for the module. The pressure transducer module also includes a temperature sensor. A weighing system includes a weighing platform or structure; at least one pressure transducer module; and hydraulic transducers for measuring the load applied to the weighing platform or structure. A controller receives the outputs of the sensors and applies the calibration data to calculate the weight of the load on the platform.

Abstract: An apparatus for measuring the dimensions or volume of an object on a conveyor is disclosed. A light source on one side of the conveyor is focused onto a spinning scanning drum having a pattern of holes therethrough. The holes are arrayed in a spiral pattern. The rotating drum is positioned parallel to the dimension to be measured between the source of light and a light detector on the other side of the conveyor from the light source. The pattern of holes is arranged so that when the scanning drum rotates a scanning pattern is generated across the conveyor. The light detector on the other side of the conveyor generates an output signal each time a beam of light passes through the rotating scanning drum and across the conveyor. A controller receives the output signal and correlates the output signal with the scanning pattern using a look-up table. Using this information, the controller determines from the scanning pattern and the detected output signals, the dimension of the object.

Abstract: A modular checkweigher/grader system is disclosed. A feed conveyor is provided for directing items to be weighed to a weighing conveyor. The entire system is modularly designed using lightweight durable materials, such as plastics and stainless steel. Each conveyor includes a conveyor belt in contact with upper and lower surfaces of a platform. The belts are tightened and loosened with quick release tension clamps and driven by air powered motors. The feed conveyor is attached to a frame by toggle clamps. The weighing conveyor is attached to a load cell which is connected to the frame by toggle clamps. These toggle clamps permit the entire feed and weighing conveyors to be easily removed. All of the air and electrical connector to the conveyors are by quick release connectors. The entire weighing conveyor is used as the weighing platform. A tachometer may be used to regulate the conveyor speed. A modular grading conveyor is disclosed for categorizing objects from the weighing conveyor.

Abstract: A microprocessor (8) controlled power-saving electronic measuring system is disclosed. A load cell (1) generates an output signal indicative of the magnitude of the load applied to the cell (1). A DC power supply (2) is switched to supply the load cell (1) with power pulses (10) at varying frequencies and duty cycles determinable by the microprocessor (8) to optimize battery life. The microprocessor (8) determines the optimal duty cycle and frequency for the power pulses responsive to desired parameters. The circuitry of the present invention is located in close proximity to a temperature sensor (34) which accurately reads the temperatures of all of the components and compensates for all heat related inaccuracies simultaneously. The microprocessor (8) determines a temperature corrected value for the load cell (1) output via a previously programmed table containing the temperature response characteristics for the load cell (1) and the circuitry.

Abstract: An electronic weighing system is disclosed which, employs spaced cylindrical dielectric rings as the load measuring transducer. A support structure is provided to linearly vary the spacing between the rings responsive to applied load which will linearly vary the resonant frequency of the rings. In an active mode, each microwave load cell is excited by an unstable oscillator, the dielectric rings stabilizing the oscillator at a resonant frequency which is proportional to their spacing. The oscillation frequency of the load cell is measured and used to compute the magnitude of the load applied to the cell based upon a predetermined relationship between output frequency and load. A plurality of multiplexed load cells may be employed. In a passive mode, a voltage controlled oscillator generates a microwave signal which linearly sweeps a preset frequency band. The sweeping signal is applied across the dielectric rings which generate a detectable pulse at their primary resonant frequency.

Abstract: A load indicator conversion system is disclosed for converting a scale having a mechanical measuring system, such as a conventional portable beam scale, into a scale having an electronic measuring system for providing an electronic display, such as an LCD display, corresponding to the load applied to the mechanical load receiver of the scale, such as the scale platform [104], which is mechanically linked via the beam load rod assembly [110] and an s-hook arrangement [150] to a load cell transducer [1]. A single common temperature sensor is employed adjacent the load cell and the associated electronics to provide information on the variations in temperature to the microprocessor for enabling temperature compensation to take place.

Abstract: A vapor and moistureproof electrical component such as an electrical load cell is formed by mixing a light oil such as mineral oil with liquid silicone gel and then curing the mixture in place to encapsulate an electrical component.

Abstract: The electronic measuring system includes a novel power supply which converts D.C. from a D.C. source to voltage pulses to drive a transducer. During intervals between transducer power pulses, an automatic drift compensation system stores an indication of system drift for use during a subsequent power pulse period. The system includes stability sensing means which render the system inoperative for measurement purposes when the signal from the measuring transducer is unstable. A plurality of sample measurement signals are taken and stored, and then passed through a programmable low pulse filter to accomplish a measurement. Thus each measurement is the result of a plurality of measurement cycles.

Abstract: The electronic measuring system includes a novel power supply which may receive power from a D.C. or A.C. source but which is particularly adapted to convert D.C. battery power to higher voltage pulses to drive a transducer. During intervals between transducer power pulses, an automatic drift compensation system stores an indication of system drift for use during a subsequent power pulse period. The system includes stability sensing means which render the system inoperative for measurement purposes when the signal from the measuring transducer is unstable. To compensate for a loss of time, the system automatically operates for a short period at a rapid rate subsequent to a period of input signal unstability.A novel indicator system and indicator control unit is employed wherein up-down counters are controlled in the indicator for rounding purposes.

Abstract: The vehicle weighing system for a towed vehicle includes removable stub axles and a hitch rigidly connected to a load support. The hitch and one or more of the stub axles are gauged in an identical manner. Two active electrical strain gauges are placed in a hole formed in the supporting member to be gauged, such hole extending normal to the direction of the load. The hole is placed adjacent the end of the supporting member which is remote from the load support and the two gauges are oriented to reduce the moment sensitivity of the system to a minimum. The hitch is provided with additional compensating gauges which are not responsive to strain, and the axle and hitch gauges are connected to form a measuring bridge circuit. The gauging holes are sealed by end plugs, a printed circuit board, potting compound and a boot, all of which are flexible so as not to interfere with the weight measurement.