Helical springs

73.20 - Springs and leaves -forsprings, of iron or steel. 7320.10 - Leaf-springs and leaves therefor 7320.20 - Helical springs 7320.90 - Other The heading covers iron or steel s rings of all types, irrespective of their use, other than clock or watch springs of beading 91.1z fiom sheet metal, wire or rod of an elastic quality, in such a way that they of returnin to. their original form even after considerable displacement. the fol owing types of spmgs : k (A) Leaf-springs (single or laminated) chiefly used in the suspension systems of vehicles (e.g., railway locomotives and rolling stock, automobiles and carts). (B) Helical springs of which the two major groups are : (1) Helical coil s rings, comprisin compression, tension and torsion springs, made from wire or rod o round or rectandar section. They are used for numerous purposes (e.g., in vehicles and general engineering). P (2) Volute springs, usually conical and made fiom wire or rod of rectangular or oval section or from flat strip. They are mainly used in shock-absorbers, buffers on rolling stock couplings, secateurs, hair clippers, etc. (C) Plat springs and flat spiral springs as used in spring operated motors, in locks, etc. (D) Discs springs and ring springs (as used in railway buffers, etc.). Springs may be equipped with U-bolts (e.g., for leaf-springs) or other fittings for assembly or attachment. Leaves for springs are also classified in this heading. The heading excludes : (a) Springs for shafts or sticks of umbrellas or sunshades (heading 66.03). (b) Spring washers (heading 73.18). (c) Sfring assembled with ofhersarticlesto form, for example, automatic door closers (beading 83.02), 1 enh able parts of machinery (Section XVI) or of the apparatus and instruments of Chapters 90,91, etc. (d) Shock absorbers, and torsion bars of Section XVII. -