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Expired Canadian patentCanada

Hydraulic control apparatus

CA 1096749 A · Owner: National Advanced Drilling Machines, Inc. · Inventors: Homanick, George; Bromell, Raymond J.

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

HYDRAULIC CONTROL APPARATUS, . ABSTRACT OF THE DISCLOSURE Disclosed are methods and apparatus for controlling the flow of hydraulic fluid to and from a work cylinder. The disclosed system includes a reversible variable displacement pump interconnected between a work cylinder and a selector valve which may connect the pump with any of a plurality of fluid reservoirs. The fluid reservoirs contain hydraulic fluid at variable pressures so that the pressure at the work cylinder may be raised to pressures well above the pressure differential capacity of the pump at maximum flow rate by selectively increasing the pressure on the reservoir side of the pump. The system includes means for controlling …

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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 March 3, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 3, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 18, 1979
GrantedMarch 3, 1981
Term endedMarch 3, 1998
Patent numberCA 1096749 A
Classification (IPC)F15B11/06 +2 more

Timeline

Timeline From CIPO dates

1980198219841986198819901992199419961998Application filedMay 18, 1979Patent grantedMarch 3, 1981Term endedMarch 3, 1998

Sources & verification

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