Mechanical arm including a counter-balance

摘要

A mechanical arm comprises a forearm, a spring, and an upper arm disposed between the forearm and the spring, wherein the forearm applies a moment to the upper arm. A copying device associated with the upper arm copies a force associated with the moment to the spring. The spring is adapted to apply a counter-force resisting at least a portion of the moment to reduce a torque for urging the forearm.