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Expired Canadian patentCanada

Method of and apparatus for the investigation of inaccessible subterranean spaces such as boreholes

CA 1233662 A · Owner: Bergwerksverband G.M.B.H. · Inventors: Heising, Ferdinand; Knickmeyer, Wilhelm

CIPO record

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

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Abstract From the Canadian patent

A method of and an apparatus for investigating subterranean boreholes especially in bituminous coal mining. Optical fiber cables carry light for illuminating the hole into the latter and an image of the wall of the borehole from the latter to an evaluating means external of the borehole.

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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 March 8, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 8, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 31, 1985
GrantedMarch 8, 1988
Term endedMarch 8, 2005
Patent numberCA 1233662 A
Classification (IPC)G02B23/26 +2 more

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedMay 31, 1985Patent grantedMarch 8, 1988Term endedMarch 8, 2005

Sources & verification

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