Hydraulic drive and control system
CA 2179805 C · Owner: Foster, Raymond Keith · Inventors: Foster, Raymond Keith
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A switching valve has a control rod with a pilot chamber at each of its ends. For each pilot chamber there is a first passageway connected to a pressure line and communicating with the pilot chamber. A second passageway is connectable to return. A relief valve has a valve member biased to close an orifice to close communication between the pilot chamber and the second passageway. The valve member has an open position in which the pilot chamber is connected to return via the second passageway to allow shifting of the control rod. In a first embodiment the pilot chamber is continuously in communication with pressure via the first passageway and the valve member is opened by this pressure in …
Read the whole patent
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 June 24, 1996 and granted February 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 24, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 24, 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.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.