Kabushiki Kaisha Ishida Koki Seisakusho

Mitito Utsunomiya

Kazufumi Naito

Satoshi Konishi

A weight sensing apparatus has a weight sensor provided with a load cell for producing an output signal indicative of the weight of an article, and a support for supporting the weight sensor. The apparatus includes oscillation sensing means provided in the vicinity of the load cell for producing an output signal indicative of an oscillation component caused by floor oscillation, a summing amplifier for adding the output signal from the load cell and a signal which is the inverse of the output signal from the oscillation sensing means, and signal processing means for processing the output of the summing amplifier to remove an oscillation component contained in the output signal from the load cell. The oscillation component is caused by oscillation received by the weight sensor from its surroundings.

Weight sensing apparatus

A load sensor includes a fixed rigid portion, a movable rigid portion spaced from the fixed rigid portion and adapted to receive an applied load, and a shear-deformable member provided between the two rigid portions. The shear-deformable portion is provided with a transmission and a reception transducer constituting an elastic surface-wave oscillator. When a load is applied to the movable rigid portion, weight is sensed based on a deviation in the oscillation frequency of the elastic surface-wave oscillator. The fixed and movable rigid portions, as well as upper and lower beams interconnecting these portions, constitute a load-sensitive element. The latter has a side face which is closed off by a pliable membrane for sealing the shear-deformable element disposed within the load-sensitivie element. Alternatively, a corrugated bellows is connected across the fixed and movable rigid portions to seal the shear-deformable member within the bellows.

Load sensor using a piezoelectric S.A.W. device

The load-sensitive element of a load cell is provided with reduced-thickness portions for endowing the cell with flexibility, and a strain gauge is bonded to each reduced-thickness portion. A deposited aluminum tape or a deposited aluminum film, comprising a substrate and a deposited aluminum layer provided on the substrate, is bonded over each strain gauge by using an adhesive, thereby covering each strain gauge with a deposited aluminum layer. Alternatively, each strain gauge is covered with aluminum foil or a deposited aluminum film bonded in place through the intermediary of a rubber sheet interposed between the load-sensitive element and the foil or film, a space being provided around the strain gauge. Furthermore, the strain gauge is covered by a Teflon sheet non-adhesively, and further, a covering member such as a deposited aluminum film or tape covers the strain gauge from the top of the Teflon sheet.

Growing community of inventors

Kusatsu, Japan

Mitito Utsunomiya