GB1221743A - Weighing apparatus - Google Patents

Abstract

1,221,743. Weighing apparatus. SANDS MEASUREMENT CORP. 20 March, 1969, No. 14665/69. Heading G4H. In weighing apparatus, extraneous perturbations are eliminated by first storing the maximum and minimum signals derived from load sensing strain gauges with no load applied and calculating their average to give a base signal, then storing the maximum and minimum signals derived with a load, the average of these signals being calculated and the base signal subtracted from it to give the actual load. As described, a wheel of a train to be weighed trips a switch 93 (Fig. 8) before it reaches the weigh rail and for a fixed time interval after this an analogue/digital converter 150 digitizes the output of bridge network 105a and after each digitization compares the newly digitized data with the previous maximum and minimum data stored in shift registers 154, 155, replacing the stored data by the new data only if it is larger or smaller, respectively, so that after a time Tt the highest and lowest signals received are stored. An arithmetic section 157 then calculates ¢(max.-min. + 2 min.) that is ¢(max.+min.) and stores this base value in base register 163. When the wheel reaches the scale a further switch 85 is operated so that the maximum and minimum signals with the weigh rail loaded are derived this process being terminated by the wheel tripping a further switch 85a. The arithmetic section then calculates ¢(max.- min. + 2(min.-base)). This is fed serially to an output register 164 connected in parallel to counter 165, the counter controlling a printer or recorder. In a modification (Fig. 16, not shown) the arithmetic section first calculates max. - ¢(max.-min.) to give the base signal and then (max. - base) - ¢(max.- min.) to give the actual load.