Ishida Co. Limited

Kabushiki Kaisha Ishida Koki Seisakusho

Ishida Scales Mfg. Co., Ltd.

Ishida Scales Manufacturing Company, Ltd.

Kazufumi Naito

Hiroyuki Konishi

Michito Utsunomiya

Yoshihiro Nakamura

Setsuo Haze

Shotaro Tamai

Hideo Nobutugu

Yukio Nakagawa

Yukio Wakasa

Seiji Yamada

Mitito Utsunomiya

Kenji Imai

Shuji Murata

Seiji Nishide

Satoshi Konishi

Katsuaki Kono

Yutaka Tamai

Shoko Tajiri

Taro Hijikata

Naoki Sasaki

Noboru Kosugi

Hirofumi Yamamori

Toshiro Ono

Kouji Itoh

Takao Suzuki

Matsuo Zama

Hidekatsu Tokumaru

A load cell is constructed with several strain gauges. Each of the strain gauges are formed with a meandering conductive portion on a substrate or base member. Portions of the meandering conductive layer defines a predetermined tab ratio. The base member is formed with a predetermined amount of filler and the tab ratio is pre-determined such that the creep characteristic of the strain gauge is substantially zero in a load cell having a generally low rated load.

Method of producing a load cell

A combinatorial weighing or counting apparatus having a dispensing feeder and weighing hoppers is provided to achieve superior article transport by suitably controlling the operating parameter of the dispensing feeder. The combinatorial weighing or counting apparatus of the present invention includes a dispensing feeder a plurality of weighing hoppers a weighing device and a DF operating parameter calculating unit Articles to be weighed are supplied to the dispensing feeder From the dispensing feeder the articles are supplied to the weighing hoppers The weighing device is a means for detecting the weight of the articles on the dispensing feeder The DF operating parameter calculating unit is a means for controlling the amount of articles that are discharged from the dispensing feeder based on weight information from the weighing device

Combinational weighing or counting apparatus

A weighing machine, such as a combinational weighing machine, has scale cells and a plurality of dummy cells installed on the same floor. The scale cells output weight signals corresponding to the weights of objects being loaded. The mode of vibrations of the floor is detected from dummy signals from the dummy cells, vertical displacements of the floor at the positions of the scale cells are calculated, and their effects are eliminated from the weight signals. Those of the scale cells not selected after a cycle of combinational calculations can be used as dummy cells in the next cycle. A memory device may be provided to store preferred combinations of such scale cells not selected that may be used for this purpose. Effects of the floor vibrations can be eliminated more accurately if the differences in sensitivity among the cells due to physical characteristics of the individual cells and/or due to the different loads on them can be taken into account either by a feedback calculation or by a formula.

Method of and means for correcting effects of floor vibrations on weight

A multi-point cell type weighing machine has a plural number of scale cells set on a floor to support a table and to output weight signals indicative of weights measured thereby of a target object placed on the table. One or more floor vibration detecting cells are set on the same floor and output floor vibration detection signals indicative of the vibrations of the floor. The weight signals are corrected on the basis of vibration components of the floor vibration detection signals. A standard weight is placed at a larger plural number of places on the table than there are scale cells and output sensitivity ratios among the scale cells are calculated from outputted values from the scale cells, and the weight signals are further corrected on the basis of the output sensitivity ratios. These weight signals are added together and the weight of the target object is obtained from the added signal. A plurality of floor vibration detecting cells may be set on the floor, each near different one of the scale cells, or they may be set anywhere on the floor and a mode of floor vibrations may calculated from their outputs. A single floor vibration detecting cell may be set between the scale cells. The table is supported by the scale cells through elastic pieces such that only vertical forces are communicated to the scale cells.

Multi-point cell type weighing machines

A load cell includes a strain inducing element having a fixed rigid body fixedly secured to a base support, and a plurality of transverse beams spaced one above the other and connecting the fixed and movable rigid bodies together. Each of the transverse beams has first and second strain generating areas defined therein in spaced relation to each other at respective locations adjacent the fixed and movable rigid bodies. A bridge circuit for outputting a load signal of a magnitude proportional to strains generated at the strain generating areas includes strain gauges for detecting the strains generated at the strain generating areas, adjusting elements for adjusting a balance of the bridge circuit, and lines connecting them together. A circuit portion of the bridge circuit which includes at least the strain gauge and some of the lines is formed in a predetermined pattern on one surface of the strain inducing element so as to straddle between the first and second strain generating areas. Not only is the circuit portion symmetrical with respect to a point intermediate between the first and second strain generating areas, but also the strain inducing element has left and right portions, including the fixed and movable rigid bodies, which are symmetrical to each other.

Load cell weighing apparatus using the same

A load cell for use in detecting a load imposed thereon which includes a body (30) in which strain is induced in proportion to the imposed load, and a strain sensor (40) for detecting the strain induced in the body (30). The body (30) is a plate member having a longitudinal axis (X) and the strain sensor (40) is mounted on the body (30). The body (30) has an opening (31) defined therein at a location intermediate of the length of the body (30) so as to define a fixed rigid body forming region (70) at one end thereof, a movable rigid body forming region (71) at the opposite end thereof opposite to the fixed rigid body forming region (70) in the longitudinal direction (X), and side connecting strips (30b, 30b) spaced by the opening (31) from each other in a widthwise direction (Y) of the opening (31) and connecting the fixed rigid body forming region (70) and the movable rigid body forming region (71) together. The strain sensor (40) has opposite ends (41c) spaced in the longitudinal direction (X) and mounted on the body (30) with its opposite ends (41c) fixed to the fixed rigid body forming region (70) and the movable rigid body forming region (71).

Load cell

A weight measuring apparatus which comprises an input signal switching circuit for selectively outputting analog signals input to a plurality of channels, analog-to-digital converter for converting an analog signal output from the input signal switching circuit into a digital signal, and a digital signal processing circuit for filtering a digital quantity output from the analog-to-digital converter for each channel, or filtering digital quantities from a plurality of channels after these digital quantities have been combined together.

Weight measuring apparatus

In order to increase both the weighing accuracy and the weighing speed of a weighing apparatus, a delta.multidot.sigma analog-to-digital converter (4) having a cut-off frequency higher than that of an analog filter (3) is connected with the output of the analog filter (3). Also, in order to perform a quick drift correction of an amplifier (2), the analog filter (3) is selectively switchable so as to perform a filtering function during a weighing mode and to perform a buffering function during a correction mode correcting means (52) is provided for storing the digital signal from the delta.multidot.sigma analog-to-digital converter (4) as a drift signal (df) during the correction mode and for providing a corrected digital weight signal (d2) by subtracting the drift signal (dr) from the digital weight signal (d1) obtained from the delta.multidot.sigma-type analog-to-digital converter (4) during the weighing mode.

Accurate and responsive weighing apparatus with drift compensation

A weighing device has not only a scale cell which weighs an object and outputs a weight signal indicative of the measured weight value but also a vibration-detecting load cell for detecting the vibrations of the floor to which the scale cell is set such that the effects of the floor vibrations can be subtracted from the weight value detected by the scale cell. The vibration-detecting load cell has attenuation-adjusting members adhesively attached to strain-generating parts of its load-sensitive element such that the attenuation constant of the load cell is thereby increased at least by a factor of 2. The usable dynamic range of the load cell can thus be increased while the load cell is kept compact. Butyl rubber members can be used for this purpose.

Load cell for detecting vibrations and weighing device comprising same

A load cell for detecting a load imposed thereon and for improving the productivity thereof. The load cell includes a strain inducing device (1) made of metal and including a strain generating area (6) for generating a strain as a function of the load, and a strain sensor (40) including a metal substrate (41) having a strain detecting element (43) formed thereon for detecting the strain generated at the strain generating area (6) of the strain inducing means (1). The strain sensor (40) is mounted on the strain inducing device (1) with the metal substrate (41) welded thereto.

Load cell and weighing apparatus including a strain sensor welded to a

To facilitate the adjustment of the accuracy and servicing maintenance of the electronic weighing apparatus, the weighing apparatus comprises a load cell and a signal processing circuit for processing a load signal from the load cell to provide a weight signal indicative of the load. The load cell includes a strain inducing element capable of producing strains in proportion to the load imposed thereon, and a bridge circuit, having a pair of strain gauges fixed on the stain inducing element and a plurality of resistors. A load signal is taken from a junction between the strain gauges and reference voltage signals are taken from junctions between the resistors. The load signal and the reference voltage signals are supplied to the signal processing circuit. If each of the strain gauges is employed in the form of a temperature compensating resistor having a characteristic effective to compensate for both of the temperature coefficient of thermal expansion of the strain inducing element and the temperature coefficient of the Young's modulus, the number of necessary component parts can be reduced.

Weighing apparatus

A load cell for use in detecting a load imposed thereon which includes a strain inducing unit (1) having a longitudinal axis and including a strain generating area (6) for generating a strain as a function of the load, and a strain sensor (40) including a substrate (41) having a strain detecting element (43) formed thereon for detecting the strain generated at the strain generating area (6) of the strain inducing unit (1). The strain inducing unit (1) includes a fixed rigid body (2), a movable rigid body (3), first and second beams (4) connecting the fixed rigid body (2) and the movable rigid body (3) together, and an intermediate plate structure (30) fixed to and positioned between the fixed and movable rigid bodies (2 and 3). The intermediate plate structure (30) has a cut space (P) defined therein at a location intermediate between the fixed rigid body (2) and the movable rigid body (3). The strain inducing unit (1) is of a symmetrical profile with respect to a geometric center point (C) of the load cell and having a hollow defined therein and delimited by the fixed rigid body (2), the movable rigid body (3), the first and second beams (4) and the intermediate plate structure (30). The strain sensor (40) is accommodated within the hollow so as to straddle the cut space (P) and positioned substantially in alignment with a mid-center line (OX) extending past the geometric center point (C) and parallel to the longitudinal axis (X) of the strain inducing unit (1).

Load cell having a hollow and a strain gauge formed on a substrate

A combination of a weighing cell (C) with a displacement sensor (S) is disclosed, in which the weighing cell (C) includes a strain inducing element (1) having a strain generating region (55) at which strain is generated in response to application of a load thereto, and a strain gauge (56) for detecting the strain generated in the strain generating region (55), and the displacement sensor (S) includes a fixed rigid component (10), a movable rigid components (11) forming a weight element, a generally elongated beam member (20) rigidly secured at opposite ends to the fixed and movable rigid components (10, 11), respectively, so as to extend between the fixed and movable rigid components (10, 11), and a displacement detecting element (23) mounted on the elongated beam member (20) for outputting an electric signal of a magnitude proportional to the amount of displacement of the movable rigid component (11) in a direction generally perpendicular to the elongated beam member (20). The strain inducing element (1) of the weighing cell includes a fixed rigid body (52) adapted to be secured to a base (B) and a movable rigid body (57) adapted to receive the load to be measured, and first and second beams (54) rigidly secured at opposite ends to the fixed and movable rigid bodies (52, 57) and extending parallel to each other between the fixed and movable rigid bodies (52, 57). The displacement sensor (S) is fixedly carried by the fixed rigid body (52) of the weighing cell (C).

Combined weighting and displacement sensor and weighing apparatus using

A method of manufacturing individual strain sensors (20) each comprised of a generally rectangular substrate (21) having first and second major surfaces opposite to each other, a strain detecting element (23) formed on the first major surface of the substrate and having at least one pair of strain sensing areas (23a), and a pair of grooves (24) defining respective areas (21a) of low rigidity and formed in the second major surface of the substrate (21) at respective locations adjacent the opposite ends of the substrate (21) while extending across the width of the substrate with the strain sensing areas (23a) of the strain detecting element (23) positioned in register with the respective grooves (24). The strain sensors (20) are prepared from a single plate material (30) of any suitable size having first and second surfaces opposite to each other and eventually forming respective substrates (21) of the individual strain sensors (20). A plurality of spaced groove segments (31) are formed on the second surface of the plate material (30) so as to extend parallel to each other, and a plurality of strain detecting elements (23) are subsequently formed on the first surface of the plate material (30) in a substantially matrix pattern so as to assume a predetermined positional relationship with respective positions of the groove segments (31). Thereafter, the plate material (30) is cut along cutting lines (b) extending in two different directions to separate the individual strain sensors (20).

Method of manufacturing strain sensors

A load sensor is made of a load-sensitive element made preferably of an aluminum alloy, a bridge circuit with strain gauges made preferably of tantalum nitride and formed on the load-sensitive element, and two operational amplifiers with their non-inversion input terminals connected respectively to the signal output terminals of the bridge circuit and their inversion input terminals connected to each other through a temperature-sensitive resistor having a positive second-order temperature coefficient and a precision resistor. The resistance values of these resistors are adjusted so as to compensate for the first-order and second-order temperature coefficients of the temperature-dependent output from the bridge circuit.

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Shiga, Japan

Kazufumi Naito