Leaf spring

Claim 1

A leaf spring used in an automotive motor vehicle suspension system, and molded of plastic material reinforced with a large number of embedded fibers running longitudinally therealong, comprising: a single elongated main body of substantially constant width along the longitudinal direction thereof, said main body having end portions, a central portion and intermediate taper portions of substantial length between said end and central portions, and an elongated rib integrally extending from said main body in a direction perpendicular to the width direction of the main body, said single main body having a thickness which decreases gradually from the end portions thereof to the central portion thereof along the longitudinal direction thereof, the end portions being thicker than said central portion, and the thickness of at least said intermediate taper portions gradually varying in the longitudinal direction of said main body so that said intermediate taper portions are thicker adjacent said end portions than at said central portions, and said rib projecting integrally from said main body in the direction of the thickness of said main body and substantially perpendicular to said main body, said rib extending along the longitudinal direction of said main body over at least a major portion of the longitudinal length of said main body, said rib having a height, in the thickness direction of said main body, which gradually increases from the end portions to the central portion of said main body, and wherein the total cross sectional area of said main body and said rib and the width of said main body being respectively substantially constant at every position along the longitudinal direction of the leaf spring, whereby the stress at each portion of the intermediate taper portions is substantially uniform along the complete longitudinal length of the intermediate taper portions.