Hollow section for coupling with other sections

Abstract

A coupling including a first hollow section having longitudinal corrugations and a second section having an aperture therein. The coupling is made according to the method including the steps of inserting the first hollow section having longitudinal corrugations into the aperture in the second section so that at least a portion thereof including the corrugations extends into and beyond the aperture, the first hollow section being selected so that its cross-sectional length exceeds the perimeter of the aperture. At least the portion of said first hollow section beyond said aperture is then expanded so as to smooth the corrugations, while avoiding stretching the wall of the first hollow section whereby the exterior size of the hollow section exceeds the entire perimeter of the aperture and the cross-sectional length remains unchanged.

Dependencies are inferred from the claim text.