Thermocompensated spring and manufacturing method thereof

摘要

The spring has a section comprising a metallic material e.g. ferro manganese alloy or nickel iron alloy i.e. Invar(RTM: Nickel steel alloy). The section has a face provided with an external layer that comprises another metallic material i.e. stainless steel. Thermoelastic coefficient of the latter metallic material varies in direction opposite to that of the former metallic material, where one of the metallic materials is paramagnetic. The external layer runs over the entire length of the spring. An independent claim is also included for a method for manufacturing a spring for a sprung balance.