Heavy goods vehicle axle load detector - uses four strain gauges mounted in pairs on front and rear axle, connected in wheatstone bridge

摘要

The load supported by the axle of a heavy goods vehicle is detected by an extensometer gauge mounted on the vehicle axle at a neutral position. This permits direct measurement of the load. Four strain gauges (31, 32) are mounted in pairs on the front and rear of the axle of a vehicle with their windings symmetrically inclined w.r.t. the vertical axis. This ensures that the one gauge is sensitive to compression (32, 32') while the other senses tension (31, 31'). The gauges are connected into a Wheatstone bridge circuit such that adjacent gauges present opposing resistance variations. The nominal resistances are identical and are protected by caps to prevent temperature variations on front and rear of the axle from affecting the measurements. The potential difference (V) at bridge unbalance provides a direct reading of the load.