The tension spring is a spiral spring which bears the axial tension. The tension spring is generally made of circular cross-section material. In the case of no load, the tension spring between the coils is generally tight and there is no gap.
Each end of the loop can be pulled tightly around the loop.
The following is the necessary information for an extension spring:
(1) Free length: (a) total length, (b) length of all loops, (c) length within the hook.
(2) Control diameter: (a) outer diameter, (b) inner diameter, (c) inner diameter of casing.
(3) Wire size “wire diameter”.
(4) Material (type, grade).
(5) Number of turns: (a) total number of turns and (b) right-handed or left-handed.
(6) The form of the end.
(7) Load in the hook.
(8) Load rate, deflection, pounds per inch.
(9) Maximum tensile length.