Internal check valve
CA 2118971 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
An internal check valve for use in a linear hydraulic motor in the form of a piston-cylinder unit including a cylinder body (38) reciprocally slidable on a piston component (40). The piston component (40) includes a tubular piston rod (52) and a piston head (60) defining first and second working chambers (136, 140) within the cylinder body (38). The tubular piston rod (52) includes a center tube (102) located within the piston rod (52). The center tube (102) provides a fluid passageway (134) through its center which communicates with a first working chamber (136). An annular second passageway (142) is formed by and radially between the piston rod (52) and the center tube (102). A spring …
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 March 14, 1994 and granted April 20, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 14, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 14, 2016.
- 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.