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Expired Canadian patentCanada

Thread for high torque joint

CA 1069881 A · Owner: Reed Tool Company · Inventors: Askew, Warren E.; Winship, Thomas E.

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 threaded connection for the stem of raise bore mining drills has substantially extended fatigue life as a result of relieving the radius of the bottom of the thread roots and cold working the relieved radius. The endurance life of the threaded connection is greatly increased by reducing the stress concentration in the thread root and placing the thread root in compression.

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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 January 15, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 15, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedJanuary 15, 1980
Term endedJanuary 15, 1997
Patent numberCA 1069881 A
Classification (IPC)E21B17/04 +1 more

Timeline

Timeline From CIPO dates

198119831985198719891991199319951997Patent grantedJan 15, 1980Term endedJan 15, 1997

Sources & verification

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