Scale employing wheatstone-type bridges and strain gages

摘要

A scale including a rectangular base frame supporting on opposite sides horizontally disposed torsion bars having their central portions secured to said frame and including a horizontal, plate-like rectangular platform superposed to said frame and bars. End portion of said bars support said platform by upstanding, threaded members engaged in said bars, eccentric seats on threaded member heads, and balls on said seats on which the platform rests. General platform leveling can be achieved by full-turn rotation of the threaded members and scale calibration adjustment can be facilitated by less than full-turn adjustment of said threaded members thereby shifting the locations of the balls along the torsion bars. Each torsion bar end portion has an upper and a lower strain gage for a total of eight. Two modified Wheatstone bridges use the strain gages for all resistors of the bridges whereby all bridge resistors are active and the two bridges form the sole electrical means to measure load on the scale.