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Expired Canadian patentCanada

Method of making a transformer core comprising strips of amorphous steel wrapped around the core window

CA 2042253 C · Owner: Klappert, Willi · Inventors: Klappert, Willi; Houser, William Kirk

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

Groups of amorphous steel strips, cut to appropriate length from a composite strip are stacked, in longitudinally-staggered relationship to form packets. The groups are made up by a process that comprises a pre-spooling operation that results in the strips and groups in each packet adhering together even, though dry. The individual packets are fed successively into a belt nester that includes a rotatable arbor and wrapping means that wraps the packets in superposed relationship about the arbor as the arbor rotates thereby building up a hollow core form. The above-described adhesive effect precludes the strips and groups from shifting longitudinally while the packets are being wrapped about …

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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

  • Filed May 9, 1991 and granted August 15, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 9, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 9, 2013.
  • 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 9, 1991
GrantedAugust 15, 2000
Term endedMay 9, 2011
Patent numberCA 2042253 C
Classification (IPC)H01F41/02

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedMay 9, 1991Patent grantedAug 15, 2000Term endedMay 9, 2011

Sources & verification

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