About Extension Springs

The extension spring is a helical cylindrical spring with coils adjoining each other capable of carrying the outer opposing forces actuating apart in its axis.

Dimensions

d	wire diameter [mm, in]
D	mean spring diameter [mm, in]
D₁	outside spring diameter [mm, in]
D₂	inside spring diameter [mm, in]
H	working deflection [mm, in]
t	pitch of active coils in free state [mm, in]
o	eye height [mm, in]
s_x	spring deflection [mm, in]
L_x	spring length [mm, in]
F_x	working force exerted by the spring [N, lb]
W₈	deformation energy [J, ft lb]
x	index responding with the spring state

Coiling

Right (usually)
Left (must be notified in words)

States

Free: the spring is not loaded (index 0)
Preloaded: smallest working load is applied to the spring (index 1)
Fully loaded: maximum working load is applied to the spring (index 8)
Limit: the spring is depressed up to coil touching (index 9)