Patent ID: 7497566

Claim:
A load mechanism for applying a load force, the load mechanism comprising: a crank having a crank pivot; a spring attached to the crank at a spring attachment; a load connector attached to the crank at a load connector attachment; wherein the load connector has a load connector direction of action relative to the crank; wherein the load connector direction of action has a load connector effective radius extending perpendicular to the load connector direction of action from the crank pivot to the load connector direction of action; wherein longitudinal movement of the load connector causes rotational movement of the crank about the crank pivot; wherein rotational movement of the crank changes the length of the spring; wherein the spring has a spring direction of action relative to the crank; wherein the spring direction of action has a spring effective radius extending perpendicular to the spring direction of action from the crank pivot to the spring direction of action; and wherein as the crank rotates in a first rotational direction over a predetermined rotational movement of the crank, the length of both the load connector effective radius and the spring effective radius change, and the change in the length of the load connector effective radius is different from the change in the length of the spring effective radius.