Shaft stiffened by axial pre-stress

Abstract

A long shaft comprising a number of axially pre-stressed members, one inside the other, the sum of the bending rigidities of the axially tensioned members is greater than the sum of the bending rigidities of the compression members, is enhanced in bending stiffness such that the end deflection of the shaft under a simultaneous transverse load and the axial force has an end deflection less than the end deflection of the same shaft, which has no pre-stress. The long shaft may be a golf club shaft. An example shows a flex “s” golf shaft, which ordinarily has an end deflection of 3.5 inch, measured from the deflection board, is stiffened into a super stiff shaft with end deflection of 1.54 inch, without having a weight increase or a change of material.

Dependencies are inferred from the claim text.