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Expired Canadian patentCanada

Load responsive trigger interval control for induction heating apparatus having inversely parallel connected thyristors

CA 1104660 A · Owner: Matsushita Electric Industrial Co. Ltd. · Inventors: Kiuchi, Mitsuyuki; Wakita, Hitoshi; Yoshida, Hirokazu

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Abstract From the Canadian patent

An induction heating apparatus of the invention is provided with a pair of inversely parallel connected thyristors which receives power from a low frequency energy source. Depending on the polarity of the source voltage, one of the thyristors is triggered into conduction by a control pulse generated in delayed response to a sensed forward bias potential at its anode for the purpose of supplying a forward current to a commutating circuit which is tuned to a high frequency in the ultrasonic range, whereupon a backward current is generated. The backward current is commutated through the other thyristor to complete a high frequency oscillation. A detector is provided to detect when the …

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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 July 7, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 7, 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.
FiledSeptember 19, 1978
GrantedJuly 7, 1981
Term endedJuly 7, 1998
Patent numberCA 1104660 A
Classification (IPC)H05B6/04 +2 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedSep 19, 1978Patent grantedJuly 7, 1981Term endedJuly 7, 1998

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