Rotary for use in a power tong
CA 2089638 C · Owner: Weatherford/Lamb, Inc. · Inventors: Pietras, Bernd-Georg
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The rotary (2) of a power tong (1) contains a master piston and cylinder (19) which, when actuated, delivers hydraulic fluid to slave hydraulic piston and cylinders (14 15) which apply active jaws (8, 9) against a pipe (5). The master piston and cylinder (19) can be depressed by a plunger (29) mounted on top the tong housing (45). The active jaws (8, 9) can be released by opening one or both valves (39, 40) mounted on the rotary (2) and actuable by depressing a ring (49) mounted on the top of the tong housing (45).
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 23, 1992 and granted September 28, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 23, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 23, 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.