What is a pharmaceutical torsion balance?
In a two pan balance the torsional principle is able to be implemented by means of three trusses, each having a paper thin stainless steel ribbon about one millimeter wide, and under high tension, traversing the perimeter of each truss. There are two parallel beams that are clamped to these high tension ribbons at the top and bottom of the trusses. When weight is applied to one of the pans, which are situated above each end truss, the force is transmitted to the beam-truss system, causing that side to move downward, with an opposing torque in the steel ribbons which is proprotional to the weight applied. The twisting metal bands ingeniously replace the knife edge of a conventional fulcrum type balance, and so there is nothing to wear out, and these balances will retain their accuracy indefinitely.
