Core and a method of manufacturing such
CA 2248665 C · Owner: Korhonen, Pertti · Inventors: Korhonen, Pertti
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a method of manufacturing a core especially , a spiral core, from superimposed plies of board produced by winding glueing, and drying such, whereby the moisture contents of at least some of the board plies entering the winding stage differ from each other in order to provide a stepwise moisture structure within the core wall. This decreases unfavourable stresses which are produced in the drying stage if a core is manufactured from plies having equal moisture contents.
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 March 10, 1997 and granted January 29, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 10, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 10, 2019.
- 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.