# Compression Spring Loads

## Compression Spring Design Resources – Spring Loading

When deflection of a compression spring is known, loads are determined by multiplying deflection by the spring rate. When the stress is known, or assumed, loads are determined from the torsional stress equation. The procedure used to determine compression spring loads of variable rate springs is complex. In this case, the compression spring load deflection curve is approximated by a series of short chords. The spring rate is calculated for each chord and multiplied by deflection to obtain the load. The load is then added to that calculated for the next chord. The process is repeated until load has been calculated for the desired value of deflection.

Compression spring loads should be specified at a test height. Because the load deflection curve is often not linear at very low loads or at loads near solid, loads should be specified at test heights between 15 and 85% of the full deflection range.

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### Resource Illustration

Compression spring loads should be specified at a test height. Because the load deflection curve is often not linear at very low loads or at loads near solid, loads should be specified at test heights between 15 and 85% of the full deflection range.