Yamato Scale Company, Limited

Shinichi Inoue

Ryuichi Hirota

Masami Yamanaka

Yasushi Oshima

Kazuo Nakayama

Shinji Yamashita

Yoshiharu Toyoda

Junichi Hayashi

Masatomi Tsuruoka

Frank E Pringle, Jr

Hiroshi Kishida

A digital filter for filtering a weight indicative signal provided by a weighing device to remove undesirable oscillatory components caused by mechanical vibration of the weighing device. The filter has a plurality of notch frequencies in its transfer characteristic within and/or near the frequency range including such undesirable oscillatory components. The filter utilizes a transfer function of multiplex progressing averages of a series of sample values extracted from the weight signal.

Device and method for filtering weight indicative signal from weighing

A product feeding device for use in a combination weigher which includes a plurality of conveyor troughs arranged radially for feeding product to corresponding weighing units and a central product feeder for distributively feeding product to the respective conveyer troughs. The device comprises a product detecting device which revolves around the central feeder for sequentially detecting the amount of product carried by each conveyer trough in order to control the amount of product fed to each conveyer trough.

Product feeding device for combination weigher

An electronic weighing scale is adapted to determine the weight of an object. A weight signal is generated having a direct current component indicative of the weight of the object and a superposed periodic oscillatory component. The period T.sub.1 of the periodic oscillatory component of the weight signal is determined. The weight signal is sampled at sampling intervals T.sub.2, having a relationship to period T.sub.1 defined by:

Electronic weighing scale

A foreign matter detector includes an oscillator for generating an oscillating signal, a phase shifter connected to the oscillator and adapted to provide a phase shifted oscillating signal, and an electromagnetic transducer. The transducer includes an excitation coil connected to the oscillator and two interconnected detection coils magnetically coupled to the excitation coil and adapted to produce a differential signal therebetween when an object is passed through the transducer. The detector also includes a first detector adapted to produce a first detected analog signal corresponding to the component of the differential signal in phase with the oscillating signal and a second detector adapted to produce a second detected analog signal corresponding to the component of the differential signal in phase with the phase shifted oscillating signal. The detector further includes an analog to digital converter connected to the first and second detectors adapted for converting the first and second analog detected signals into first and second series of digital values, respectively, and circuitry connected to the converter for selecting a representative value for the object from each of the first and second series of the digital values.

Detector for detecting foreign matter in object by using discriminant

A foreign matter detector includes an oscillator for generating an oscillating signal, a phase shifter connected to the oscillator and adapted to provide a phase shifted oscillating signal, and an electromagnetic transducer. The transducer includes an excitation coil connected to the oscillator and two interconnected detection coils magnetically coupled to the excitation coil and adapted to produce a differential signal therebetween when an object is passed through the transducer. The detector also includes a first detector adapted to produce a first detected analog signal corresponding to the component of the differential signal in phase with the oscillating signal and a second detector adapted to produce a second detected analog signal corresponding to the component of the differential signal in phase with the phase shifted oscillating signal. The detector further includes an analog to digital converter connected to the first and second detectors adapted for converting the first and second analog detected signals into first and second series of digital values, respectively, circuitry connected to the converter for weighting the digital values, and circuitry connected to the weighting circuitry for selecting a representative value for the object from each of the first and second series of the weighted digital values.

Detector for detecting foreign matter in an object by detecting

A dispersion feeder used in a combination weighing machine for distributively feeding product to be weighed out to a plurality of weighing units arranged around it. The feeder is characterized in that it includes a mechanism for effecting rotational movement of the center or apex of its dispersion table. This movement exerts a centrifugal force on product fed onto the table, including product in and near the center of the table, thereby ensuring that such product is removed from the table.

Dispersion feeder

A force measuring device, such as a weighing device, having device for automatically compensating for temperature-induced zero and span deviations. The device includes force and temperature sensors for producing force and temperature indicative signals, respectively. Device for processing processes these force and temperature signals at various temperatures in no-load and reference-load conditions by regressive analysis in order to obtain and store in memory equations representing the zero and span deviations with temperature. During use of the force measuring device for measurement, the device uses the stored equations to calculate the zero and span deviations from the current temperature to correct the force indicative signal.

Force measuring device

A force measuring device mainly used as a weighing device, comprising first and second horizontal cantilever members disposed parallel with each other in a common vertical plane, a weighing cradle attached to the free end of the first member, and a metal string stretched between the free ends of both members. The string is placed between a pair of magnetic poles so that it vibrates at its inherent frequency functionally relating to its tension and, therefore, a load applied to the weighing cradle. The frequency of the string is measured and the value of the applied load is calculated therefrom by an electronic calculating circuit. In order to overcome a problem of frequency deviation caused by variation in the spring constants of both cantilever members due to variation in the surrounding temperature, the inventive device includes a temperature sensor and arithmetic circuitry for applying compensation for the error due to the temperature change to the calculation of the applied force.

A load cell produces an oscillating signal indicative of the weight of the product. The maximum and minimum values of the oscillating signal are determined to provide a reference value which is an average of the maximum and minimum values. Using the reference value for the starting point and ending point, one cycle of the oscillating signal is identified and integrated to determine the corresponding weight of the product. The apparatus compensates for errors in the relationship between the actual starting and ending points of the cycle and the reference value.

Weighing apparatus and method

The weighing apparatus according to the invention is for use on a support surface which is subject to vibration. The apparatus includes a base adapted to be positioned on the support surface and having opposing first and second sides. The base is adapted to transmit vibrations from the support surface. A tray holds the product to be weighed and has a center of gravity adjacent the first side of the base. A load cell supports the tray on the base at the first side of the base. Strain gauges connected to the load cell generate a signal indicative of the weight of the tray and any product held thereby. The signal includes oscillating noise corresponding to vibrations transmitted by the base through the load cell to the tray. An auxiliary beam and counterbalance weight stablize the tray by minimizing at least some of the vibrations transmitted to the tray and by converting at least some of the lower frequency vibrations transmitted to the tray into vibrations having a frequency which is higher than the frequency of the lower frequency vibrations. The tray transmits reverse-phase vibrations to the load cell which result in noise in the signal. The auxiliary beam and counterbalance converts at least some of the reverse-phase vibrations transmitted to the load cell into vibrations having a frequency which is higher than the frequency of the reverse-phase vibrations.

Counterbalanced weighing apparatus

A digital filter or an equivalent device for filtering a weight signal provided by a weighing device to remove undesirable oscillatory components caused by mechanical vibration of the weighing device, which is constructed to have a plurality of notch frequencies in its transfer characteristic within and/or near the frequency range including such undesirable oscillatory components by utilizing the principle of transfer function of multiplex progressive averages of a series of sample values extracted from the weight signal.

An apparant density measuring device for a weighing machine comprising a bucket having a known loading volume. Product is fed to the bucket in an amount sufficient to cause overflow from the bucket, the bucket being vibrated for a specific time during this feeding operation. After completion of the feeding operation, the loaded bucket is weighed.

Apparent density measuring device

A vibrator for providing revolving vibration to a body to be vibrated such as a dispersion table of a vibration feeder or a sieve stack of a screening machine. In this vibrator, it is possible not only to control the amplitude of vibration but also to obtain a uniform vibration amplitude everywhere in the vibrating body inclusive of its center. A unique feature of this vibrator involves a plurality of armatures fixed to and around a vibrating member and actuated by associated electromagnets energized with multiphase a.c. power.

Vibrator

An automatic weighing system for delivering quantities of product measured by weight, each quantity having a weight equal or approximate to a predetermined target weight, in such manner that the volume of each quantity falls always within a predetermined allowable range even when the product to be weighed has a substantial variance in its apparent density or specific gravity. The system includes means for measuring the apparent density and means for controlling the target weight in accordance with the measured value of apparent density.

Automatic weighing system with density ratio control of volume

A novel product feeding device for a combination weighing machine. The feeding device is designed to feed a plurality of weighing hoppers of the machine with product, such as uncooked meat, having sticky characteristics so that it cannot be conveyed by vibrating conveyor troughs as used in prior art conventional combination weighing machines. The novel feeding device includes a plurality of horizontal rotating discs corresponding to respective weighing hoppers. The discs are arranged in successively overlapping fashion for transferring product fed to the discs at one sides thereof to respective weighing hoppers disposed under the discs at the opposite sides thereof.

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Kobe, Japan

Shinichi Inoue