CPC B64D 11/0619 (2014.12) [B64D 11/0648 (2014.12); B64D 11/0649 (2014.12); F16F 7/12 (2013.01)] | 19 Claims |
1. An inversion-formed double-walled tube, comprising:
an outer tube having an outer wall thickness;
an inner tube disposed inside the outer tube and having an inner wall thickness; and
a transition portion connecting the inner tube and the outer tube;
wherein at least one of the inner and outer wall thicknesses varies along a length of the double-walled tube, and wherein the inner and outer wall thicknesses vary differently from each other along the length of the double-walled tube.
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