11 - Springs

Abstract

This chapter discusses about springs, which are used to store elastic energy and when required release it. There is a wide range of types of spring that are readily available from specialist suppliers or that can be designed and manufactured fit-for-purpose. The chapter introduces spring technology and outlines the principal steps in the design of helical compression, extension and torsion springs, leaf springs, and Belleville washer springs. Typical properties of common spring materials are listed. One approach, knowing the force and length of the spring, is to specify a material, guess a trial diameter for the spring considering the space available, check the values calculated for spring rate and free length, and if necessary, try a new wire diameter. Further, the chapter explains various configurations of torsional springs and that Belleville spring washers comprise a conical shaped disc with a hole through the center. The chapter has introduced the function and characteristics of a range of spring technologies, and has outlined the design methods for helical compression, extension and torsion springs, leaf springs, and Belleville spring washers. There is no single design procedure that is suitable for all types of spring and the aforementioned procedures have not considered all of the important design parameters, which also include cost, appearance, and environmental considerations. Spring design invariably becomes a process of optimization where various trade-offs need to be balanced to provide the best possible total solution.