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Expired Canadian patentCanada

Self contained gas spring interchangeable with coil spring

CA 1280451 C · Owner: Wallis, Bernard J. · Inventors: Wallis, Bernard J.

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

A self contained gas spring interchangeable with a coil spring comprising a cylindrical body having a constant diameter external cylindrical surface, the cylindrical body having open ends and a piston within said cylindrical body and having one end projecting through one of the openings of the cylindrical body. The piston and the cylindrical body have interengaging flanges that limit the outward movement of the piston relative to the cylindrical body. A plug is positioned in the other end of the cylindrical body to close the opening of the cylindrical body. A charging valve is positioned in the plug for charging the interior of the gas spring. The piston has a hollow inner end with an inner …

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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 February 19, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 19, 2008.
  • 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 17, 1987
GrantedFebruary 19, 1991
Term endedFebruary 19, 2008
Patent numberCA 1280451 C
Classification (IPC)F16F9/02

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedAug 17, 1987Patent grantedFeb 19, 1991Term endedFeb 19, 2008

Sources & verification

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