The lengths of the links comply with the conditions: A͞B=D͞C and A͞D=B͞C. When a load is placed on the pan, link 1 has translational motion. Link 2 and the scale sector with weight G, both rigidly secured to link 2, turn about fixed axis A until equilibrium is reached. The indicated weight depends upon the angle of rotation of the sector with weight G, and is read off the scale.
$785$LW,B$