Curling stone
CA 2083446 C · Owner: Thompson, Albert N. · Inventors: Thompson, Albert N.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A curling stone is manufactured of a two layered material a main body, and a bottom layer on which the running edge is formed. The two layers are joined along a flat mating surface that is readily formed on the main body usinga stone saw. The stone may be manufactured by the refurbishing of existing stones on which the running edge has been damaged or it may be manufactured as an original stone. A granite that is resistant to water penetration may be used for the bottom layer and a less expensive more, shock resistant granite for the main body including the striking band.
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 20, 1992 and granted October 6, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 20, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 20, 2014.
- 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.