Reverse circulation drilling system with bit locked underreamer arms
CA 2296470 A1 · Owner: Holte, Ardis L. · Inventors: Holte, Ardis L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An underreamer drill bit assembly including a pilot bit (82) and extendable underreaming arms (88) operatively connected to the pilot bit (82). The underreaming arms (88) have an extended position for underreaming and a , retracted position in which the overall diameter of the underreamer drill bit assembly is less than the inside diameter of the well casing permitting the , entire bit assembly to be withdrawn through the well casing. In another aspect of the invention, the bit assembly is operatively connected to a dual wall pipe assembly (12). A supply of compressed air is conducted through the annulus (24) of the dual wall pipe assembly (12) to a down hole pneumatic hammer (13). …
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 July 17, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 17, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 17, 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.