Weighing scale consists of a dial, rack and pinion arrangement that turns the dial, a spring and arrangement of four levers for even weight distribution.
A long lever fixed at the left end, has weight applied to it very close to the fixed end. At the right end of the lever the weight is significantly reduced by a ratio determined by the relative difference between the length from the left end to the weight and the distance from the left end to the right end. This ratio significantly reduces the weight experienced by the spring.
The spring plate moves up and down. This up-and-down motion is translated by a pivot into side-to-side motion. That motion is sent to a rack and pinion arrangement.
The rack and pinion turns the side-to-side motion into circular motion to turn the dial