摘要 |
Double helices each comprising two helix elements made from plastic wire with the longitudinal axes of the two helix elements extending in parallel and with the windings of the two helix elements intertwined, the double helices being formed by winding two plastic wires in parallel and without twist on a mandrel and being used to assemble a spiral belt by interengaging in zipper fashion a multiplicity of helices via meshing the windings of one helix with the windings of the next helix, and by inserting a pintle wire into the passage formed by the overlapping windings.
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