Importance

Loading Importance Indicators...

Abstract

Each of two pairs of electrical-resistance strain gages which are to make up a measurement bridge for a beam-type load cell is fashioned as a composite wherein two spaced-apart grids of foil-type parallel elongated filaments oriented and functioning as strain gages are made of material promoting a strain gage factor effective to compensate for elastic modulus change of the beam material as temperature varies over an expected range. Intermediate the two grids of strain-gage filaments, where a neutral position between tension and compression surface strains of the sensing element of a gaged beam may be expected to appear, the common insulating backing for the two grids carries a set of narrow strands which produce a dummy foil resistance of predetermined value needed for a calibration wherein it simulates the influence upon bridge input impedance of a temperature-compensation resistance such as would otherwise be used without the inherent compensation for elastic modulus changes by way of offsetting effects of strain gage factor of the gages. The same material which forms the foil or printed-circuit type gage grids also forms the dummy or calibration resistor upon the same underlying backing, and, in addition creates relatively large-area and low-resistance integral interconnections between the gages and resistance and tabs for needed external-wiring connections.

Loading the Abstract Image...

First Claim