Hollow profile used in the manufacture of a pipe
CA 2517159 C · Owner: Oy Kwh Pipe Ab · Inventors: Sjoeberg, Sven
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a hollow profile (1) used for the manufacture of a spirally wound double-walled thermoplastic pipe which hollow profile has , essentially a rectangular cross section and the wall (2) of the hollow profile intended to form the inner wall of the pipe is thicker than the wall (4) intended to form the outer wall (4) of the pipe. The invention is characterized in that the inner rounding radius (7a) of the edges adjacent to the thicker wall (2) of the hollow profile is considerably larger than the rounding radius (7) of the two other edges of the cavity (6).
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 23, 2004 and granted February 7, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 23, 2024.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 23, 2026.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.