Helical Compression and Extension Spring Terminology
The following recommended practice has been developed to assist engineers and designers in the preparation of specifications for the major types of helical compression and extension springs. It is restricted to a concise presentation of items which will promote an adequate understanding between spring manufacturer and spring user of the major practical requirements in the finished spring. Closer tolerances are obtainable where greater accuracy is required and the increased cost is justified.
For the basic concepts underlying the spring design and for many of the details, see the SAE Information Report MANUAL ON DESIGN AND APPLICATION OF HELICAL AND SPIRAL SPRINGS, SAE HS 795, which is available from SAE Headquarters in Warrendale, PA 15096. A uniform method for specifying design information is shown in the TYPICAL DESIGN CHECK LISTS FOR HELICAL SPRINGS, SAE J1122.
Two types of helical springs are considered:
Hot coiled compression springs for general automotive use as well as for motor vehicle suspensions.
Cold wound compression and extension springs for general automotive use.
This recommended practice uses SI (metric) units in accordance with the provisions of SAE TSB 003.