Railroad frog assembly
CA 2254511 C · Owner: Kuhn, Stephen R. · Inventors: Kuhn, Stephen R.; Young, Keith
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A railroad frog assembly is provided with a switched magnet that immediately retains a frog flexible wing rail in its open position in response to a railcar wheel passing through the frog assembly, and that delayably releases the frog flexible wing rail from its open position for subsequent closure by an included frog compression spring.
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 November 25, 1998 and granted September 11, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 25, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 25, 2020.
- 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.