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Expired Canadian patentCanada

Forming curved segments from metal plates

CA 1083937 A · Owner: General Dynammics Corporation · Inventors: Mullen, Roger F.

CIPO record

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

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Abstract From the Canadian patent

A large flat metal plate is formed to have a three-dimensional shape of compound curvature by locally heating to an elevated temperature along predetermined lines and then quickly cooling, as by using a torch which carries a water spray nozzle. The heating extends completely through the thickness of the plate, and cooling causes significant shrinkage in the plane thereof in a direction perpendicular to the line of heating. Heating is carried out along lines in a geometric pattern and in a preselected sequence involving all quadrants of the plate so that it experiences a gradual transformation overall. The plate is normally supported upon an underlying cradle shaped to the desired compound …

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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 August 19, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 19, 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.
FiledMay 25, 1978
GrantedAugust 19, 1980
Term endedAugust 19, 1997
Patent numberCA 1083937 A
Classification (IPC)B21D5/00

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedMay 25, 1978Patent grantedAug 19, 1980Term endedAug 19, 1997

Sources & verification

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