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Expired Canadian patentCanada

Hydraulic actuator

CA 2021448 C · Owner: Asea Brown Boveri Ltd. · Inventors: Frey, Heinz; Prochazka, Kamil

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

This hydraulic actuator has a drive volume (11) pressurized by extreme-pressure oil. The oil pressure is converted into a valve movement by a drive piston (10). A spring element acts upon the drive piston (10) in a manner opposing the oil pressure. The actuator is to be constructed such that extreme-pressure oil escaping from the drive volume (11) cannot cause any consequential damage. This is achieved in that the drive volume (11) is completely surrounded by a safety volume (3, 7) filled with low-pressure oil.

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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 July 18, 1990 and granted March 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 18, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 18, 2012.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 18, 1990
GrantedMarch 28, 2000
Term endedJuly 18, 2010
Patent numberCA 2021448 C
Classification (IPC)F16K31/04 +1 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedJuly 18, 1990Patent grantedMarch 28, 2000Term endedJuly 18, 2010

Sources & verification

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