Hybrid pneumatic percussion rock drill
CA 2071002 C · Owner: Fu, Chuen-Cheng · Inventors: Fu, Chuen-Cheng
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A fluid actuated percussion rock drill comprising a hollow wear sleeve (12) and a piston (14) slidingly disposed within the wear sleeve. Drive (58) and return pressure surfaces (32) bias the piston between drive and return positions respectively. A high pressure port (18) is included. A return chamber (22) is exposed to the return pressure surface (32). A drive chamber (36) is exposed to the drive pressure surface (58). A pressure sensitive valve (42) is movable between an open and a closed position. When the valve (42) is in the open position the high pressure port, (18) is connected to the drive chamber (36). The valve means (42) includes a first valve pressure surface (48) for exposure …
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 December 26, 1990 and granted October 14, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 26, 2012.
- 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.