Variable Force Spring Design

Specify tight limits only where function requires them, while preserving enough information to define the useful curve.

State the allowable force band and the position where it applies, including user effort and attachment loads.

Define the force needed at the installed starting position and the permitted transition into normal travel.

Only when the design requirement and measured behavior support it. Specify loading and unloading separately when their functions differ.

Specify the allowable transition position as well as force limits. Correct endpoints do not prove correct timing.

It may, when the required spring force is derived from the actual load and effective moment arm throughout motion.