Abstract: A method of manufacturing helical springs from steel wire. The springs' skin is thermomechanically hardened by shot peening the unstressed springs followed by thermally destressing them, and shot peening them again. The second shot peening is carried out in at least two steps. The method produces springs that are just as strong as conventional but smaller and lighter in weight. The first one of the steps is a rough shot peening with shot that is coarser than in the second one of the steps which is a fine shot peening was shot at a lower speed than in the first step. This increases compression of the wire's surface and polishes the wire's surface.

Abstract: A leaf spring to be clamped between a saddle of the vehicle axle and a clamping plate by means of two connecting elements spaced from one another in a longitudinal direction has an elongated spring member extending in the longitudinal direction, and is composed of a fiber-reinforced duro-plastic synthetic material. At least two supporting plates each have a length exceeding the length of the saddle or of the clamping plate, and each have an inner region located inside the connecting elements, and an outer region located outside the connecting elements. One of the supporting plates is located at one side of the spring member, so as to be arranged between the spring member and the saddle, the other of the supporting plates is located at the other side of the spring member so as to be located between the spring member and the clamping plate.

Abstract: A cylindrical helically coiled compression spring made of a length of wire or rod having a circular cross section, the spring having interior windings providing the main spring action and end winding portions at least one of which is arranged to be supported against a spring disc, and the wire rod being formed to have a diameter which is greater in the region of the at least one end winding portion than in the region of the interior windings.