Compression springs and methods of making same

Abstract

Compression springs, such as helical compression springs, include end portions with selectively contoured inner contact surfaces. The selective contours of the inner contact surfaces may take the form of planar, grooved, concave, or other shaped, non-circular surfaces. In addition, enough of the inner contact surface is contoured to reduce the contact stress and/or stress concentration effects on the adjacent coils when the compression spring is placed under load and the adjacent coil engages or contacts the respective end portion. The selective contouring of the end portions may be accomplished by holding the spring in a holder and moving a cutter relative to the end portion of the spring to remove the desired amount of material from the end portion.

Dependencies are inferred from the claim text.