Spring Design Menu  Spring Suppliers and Manufacturers
This calculator will determine the spring rate related to an extension spring from basic geometry and material data input. Default units are shown in inches, etc however SI (metric) can be used.
This calculator will calculate
any of the values remaining by changing one of the variables then selecting the
"calculate: button for the selected variable.
Equation: T_{F} = I_{T} + (D x k)
Where:
T_{F} = Total Force exerted on spring
D_{ }= Distance spring is deflected
I_{T}= Initial tension force on spring
k = Spring constant determined by experiment or calculation
(This calculator requires a java  enabled browser)
Open Extension Spring Force Formula and Calculator About Extension Spring Design:
Most extension springs are wound with an initial
tension. This tension is the force that holds the spring coils wound
together. The spring rate tends to be constant
over the central 60 percent of the deflection range. When
designing for a particular spring, design for critical loads and rates to be
within the central 60% deflection and load range. Standard and custom springs are
available. Exceeding manufactures maximum deflection almost always reduces
usable spring life cycles.
