Related standards and design parameters of tension spring

Related standards
GB/T_ 1239[1].1-2009_ Technical specification of cold rolled cylindrical coil spring_ Part 1: tension spring;
GB / t2087-2001 dimensions and parameters of cylindrical spiral tension spring: GB / T 2008-1997, etc.

Design parameters
Indicate the material diameter (d), outer diameter (d), total length (HO), number of working laps (n), location and shape of earrings, load (p 1, P 2 P I) and corresponding value (H1H2 HJ) as shown in the figure, if there is initial tension, PO should be noted.