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Expired Canadian patentCanada

An alumina abrasive wheel with improved corner holding

CA 2221822 C · Owner: Lundberg, Robert S. · Inventors: Lundberg, Robert S.; Sheldon, David A.

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

The present invention provides a vitreous-bonded abrasive grinding wheel wherein the abrasive grit portion comprises an alumina abrasive and wherein the wheel has improved corner or form holding characteristics and mechanical properties. The invention further includes the bond composition which allows for improved corner or form holding and mechanical properties with alumina abrasives.

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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

  • Filed April 25, 1996 and granted February 27, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 25, 2016.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 25, 2018.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 25, 1996
GrantedFebruary 27, 2001
Term endedApril 25, 2016
Patent numberCA 2221822 C
Classification (IPC)B24D3/16 +1 more

Timeline

Timeline From CIPO dates

1997199920012003200520072009201120132015Application filedApril 25, 1996Patent grantedFeb 27, 2001Term endedApril 25, 2016

Sources & verification

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