(under subclass 141.1) Process including shaping or distorting a sheet to coil upon itself at least two
convolutions to produce a tube having a wall of at least two thicknesses of said sheet, and then bonding one or more extending edge(s) of the sheet to that part of the body of the sheet juxtaposed thereto.
SEE OR SEARCH THIS CLASS, SUBCLASS:
130, for a process of progressively forming a sheath around a core, and bonding the sheath to the core.
144+, for a process of forming a tube of single thickness by bending a web into tubular form and joining the meeting edges of the web.
