Patent ID: 7707896

Claim:
A method for monitoring the net dimensional changes in a free length L of a resilient element, the free length L of the resilient element extending along the resilient element between opposing end definition points, and a separation S between a pair of non-compliant stops, the method comprising the steps of: constraining the end definition points of the resilient element between the non-compliant stops that constrain the free length L of the resilient element at a separation S that is less than L so as to cause the resilient element to bow and create a displacement m of a central region of the resilient element with respect to a line intersecting the end definition points, wherein S is further limited such that S>2 m; restricting the flexure of the resilient element with respect to its thickness such that the resilient element does not exceed its elastic limit in use; monitoring the change in the displacement m of the central region of the resilient element with respect to the line intersecting the end definition points, this change resulting from bowing of the resilient element; and correlating the change in displacement m resulting from change in bowing to a net change in the free length L and the separation S.