Gravity balancing device for rocking arm

摘要

A gravity offsetting device for offsetting the gravitational moment of a rocking arm, mounted between a fixed point located above a pivotal point of the rocking arm at a predetermined distance a and substantially in vertical alignment therewith, and an arbitrary point on the rocking arm, the gravity balancing device including: a compression spring having a spring constant k of a value corresponding to the load W at the arbitrary point as divided by the distance a, and a free length corresponding to the sum of the length l between the fixed and arbitrary points and the initial set length ls of the compression spring, and adapted to apply a counterbalancing tensile force varying in proportion to the distance between the fixed and arbitrary points.