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Expired Canadian patentCanada

Steering system and compensating valve

CA 1189421 A · Owner: Deere & Company · Inventors: Wittren, Richard A.

CIPO record

Overview

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

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Abstract From the Canadian patent

Abstract of the Disclosure, A hydrostatic power steering control system with variable feedback compensation employing a unique compensating valve. The steering control system includes first and second hydraulic cylinders, each having two internal chambers denoted as head and feedback chambers. A piston is movably retained in each of the cylinders and is attached to a piston rod which extends outwards. The pair of piston rods are connected to a pair of steerable wheels by a mechanical linkage. Fluid contained in a reservoir is pressurized by a supply pump and is selectively passed to a head chamber of one of the cylinders by a control valve. The control valve is actuated by pressure …

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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 June 25, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 25, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 23, 1982
GrantedJune 25, 1985
Term endedJune 25, 2002
Patent numberCA 1189421 A
Classification (IPC)F15B13/02

Timeline

Timeline From CIPO dates

1983198519871989199119931995199719992001Application filedFeb 23, 1982Patent grantedJune 25, 1985Term endedJune 25, 2002

Sources & verification

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