Pre-stressing for coil spring - entails application of axial compression together with coil torque with 225 degrees twist

摘要

The post-stressing and twisting process is applied to a fabricated coil spring (1), for an increase of the springs in service strength. The spring is stressed axially by the application of a compressive force (C), one of its ends being simultaneously twisted by the application of a coiling torque (T). It (1) may be treated at a temp. of 120 to 400 degrees centigrade, subjected to a post force (C) of some 650 daN. The torque (T) may be of the order of 47 daNn, effecting a twisting of some 225 degrees of a terminal coil, and applied to a free end (5) of the spring wire.