High strength spring steel
CA 2045440 C · Owner: Umezawa, Nobumasa · Inventors: Fukuzumi, Tatsuo; Uchibori, Katsuyuki; Umezawa, Nobumasa
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a high strength spring steel consisting of, in weight percentage, 0.40 to 0.70% C 0.50 to 2.00% Si, more than 0.50 to 1.50% Mn 0.50 to, 2.50% Ni, 0.20 to 1.50% Cr, more than 0.60 to 1.50% Mo, 0.01 to 0.50% V, 0.01 to 0.50% Nb, 0.005 to 0.100% Al and the balance being Fe and unavoidable impurities. The steel of the present invention has a high hardness coupled with high toughness and is very useful especially for springs used in suspension devices or other various industrial machines.
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 June 25, 1991 and granted April 16, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 25, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 25, 2013.
- 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.