Among various types of springs, helical tension springs are designed to absorb and store energy as well as create a resistance to a pulling force. These are metal wire coiled around in loops. In the manufacturing process, an initial tension is incorporated to pull the coils tight against each other. It is initial tension that determines how tightly together a tension spring is coiled. This initial tension can be manipulated to achieve the load requirements of a particular application. The initial tension is equal to the minimum force required to separate adjacent coils.
There are varieties of ends that can be put on tension springs. It may include threaded inserts, reduced and expanded eyes on the side or in the centre of the spring, extended loops, hooks or eyes at varying positions or distances from the body of the spring. These ends are very critical and generally made with standard tools in one operation. As the space occupied by the machine loop is shortened, the transition radius is reduced and an appreciable stress concentration occurs. This contributes greatly to shortened spring life and premature failure.
Often the spring is one of the last parts designed in an assembly. This means there is often limited geometry and high expectations of part life. Most tension spring failures occur at the hook as the design of the end hook impacts the stress indicates the part of tension spring and spring design. Often stresses are higher in the spring ends than in the spring body.
Our springs are engineered to withstand stress under tolerance limit and ensures longer part life due to appropriate material selection and heat treatment process done by our engineer.