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Expired Canadian patentCanada

Lightning arrester with leakage current detection

CA 1212411 A · Owner: Mitsubishi Denki Kabushiki Kaisha · Inventors: Imataki, Mitsumasa; Fujiwara, Yukio; Sonoyama, Seiji

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 lightning arrester comprises nonlinear resistance discs 2 stacked within a ceramic casing 1 with annular metal, cover rings 3, 4 being fixed to the opposite outer ends of the casing. Conductive plates 5, 19 having reduced thickness rupturable central portions are sealed to the inner ends of the casing, with the lower plate 19 being insulated from the lower ring 4 by an insulating ring 20. An ammeter 16 is connected between the conductive plate 19 and ground by a lead wire 21 passing through the ring skirt but insulated therefrom, whereby only leakage current passing through the nonlinear resistance discs is sensed.

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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 October 7, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 7, 2003.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 5, 1983
GrantedOctober 7, 1986
Term endedOctober 7, 2003
Patent numberCA 1212411 A
Classification (IPC)H01C7/12 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedJuly 5, 1983Patent grantedOct 7, 1986Term endedOct 7, 2003

Sources & verification

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