# Design of a Helical Extension Spring

Design of a Helical Extension Spring

According to Hooke's law, , the restoring force of an extension spring is proportional to its linear extension .

F=kΔL

F

ΔL

The value is the spring constant and depends on the design parameters as follows: [1]. Here is the diameter of the coil, is the diameter of the wire, is the number of active windings, and is the shear modulus of the material.

k

k=

μ

4

d

8n

3

D

D

d

n

μ