Compression springs are devices made up of helically formed coils with pitch in between used to push back on an applied force or load in order to return to its original position when the force or load is released. They are the most commonly used type of spring as well as the most economical.
When specifying a compression spring the following aspects need to be defined :
1 Wire Diameter
2 Spring length
i) Free height
ii) Installed height
iii) Maximum operating height
iv) Solid height
3 Spring Diameter
i) Outside diameter if spring is to work in a hole
ii) Inside diameter if spring is to work over a rod
4 Style of End
i) Ends closed, but not ground
ii) Ends closed and ground
iii) Open ends
5 Number of Coils
i) Number of working or active coils.
ii) If closed ends are called for, add 1 coil for each end to allow for the flattening of the coils to arrive at total coils.
Where possible give loads required at specific defections of the spring and specify tolerances acceptable.
If a rate of load per unit of deflection is required, specify the deflection at which the loads are to be measured and give acceptable tolerances.
8 Direction of Winding
Left or right hand. This may be expressed as clockwise or anti-clockwise and unless specified, will be considered optional.
9 Stress & Fatigue Life
If known, specify these requirements. This information can be computed and supplied on request.
If required to reduce initial relaxation