US Patent 11919153 Counterbalance mechanism including drive ratio

Implementations relate to a counterbalance mechanism including a force transformation mechanism that provides a drive ratio. In some implementations, a counterbalance apparatus includes a spring, a first tension element, a second tension element, a force transformation mechanism coupled to the spring by the first tension element and coupled to the second tension element, and a plurality of counterbalance pulleys coupled to the second tension element. At least one of the counterbalance pulleys is coupled to a load that is moveable with reference to a mechanical ground, and a force provided by the spring is modified in magnitude by the force transformation mechanism and is applied to the load via the second tension element. The force transformation mechanism includes a plurality of elements and the modification of the force is based on a drive ratio of the elements of the force transformation mechanism.