Slide rule for belleville springs

Claim 1

A slide rule for use in designing a Belleville spring, comprising two spaced elongated fixed members, a slide between said members and coextensive therewith, and a cursor mounted on the fixed members for movement along them, the parts of the rule having two sides on which there are the following scales: a. On one side of the rule scales for determining thickness in inches according to the formula: in which PF load at flat position E modulus of elasticity (30,000,000 for steel) sigma Poisson''s ratio q h/t h inside height, in inches t thickness OD outside diameter, in inches, in which formula steel values are substituted for material values and OD/ID 2 so that Alpha becomes a constant and sigma 0.3 E 3.0 X 107 M 0.685 Alpha 1.93 X 108 one of these scales representing values of PF from 1 to 10,000 extending from end to end of one of the fixed members, a second scale representing values of OD2 from 10 down to 0.1 on the slide adjacent and coterminous with the PF scale, a third scale representing values of t from 0.001 to 1.0 inch on the second fixed member and coterminous with PF and OD2 scales, a fourth scale on the slide representing values of q from 1.0 to 3 in the direction of 0.010 on the t scale and from 1.0 to 2 in the opposite direction and with the 1.0 value of q aligned with 0.0268 on the t scale if it is assumed that PF 100, OD 1 and q 1, and at least one scale on the slide representing values of OD/ID from 1.2 to 4, b. and on the other side of the rule scales for determining the stress at flat position according to the following formula: in which PF load at flat position OD outside diameter ScF compressive stress on convex side of the inner edge of flat, in p.s.i.