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Expired Canadian patentCanada

High bending strength ratio drill string components

CA 1256094 A · Owner: Dudman, Roy L. · Inventors: Dudman, Roy L.

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Abstract of the Disclosure, A drill collar is disclosed having a fishing neck just behind the pin end, which has a reduced dimension compared with the box end. Hence, the tool is particularly well suited for being oriented with its pin end up in a drill string. The BSR is enhanced while the collar retains good "fishability" and "washoverability" characteristics.

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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

  • Granted June 20, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 20, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 31, 1987
GrantedJune 20, 1989
Term endedJune 20, 2006
Patent numberCA 1256094 A
Classification (IPC)E21B17/00 +2 more

Timeline

Timeline From CIPO dates

1988199019921994199619982000200220042006Application filedAug 31, 1987Patent grantedJune 20, 1989Term endedJune 20, 2006

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.