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Expired Canadian patentCanada

Electric field strength indicator

CA 1191900 A · Owner: Hascal, Marcel · Inventors: Watson, Donald A.; Lopez, Sergio; Danielski, Andrew

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

An electric field strength indicator for use with high voltage conductors comprises a capacitive probe mounted within a tubular shield having an insulating spacer at one end for locating the unit with respect to a conductor under test. The probe is electrically coupled to a signalling circuit and is movable axially within the shield to a position at which a threshold response is obtained. Such position, which denotes the conductor voltage, is read on a scale provided. Because of the shield the device is directional the, probe being shielded from neighbouring conductors.

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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 13, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 13, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 15, 1983
GrantedAugust 13, 1985
Term endedAugust 13, 2002
Patent numberCA 1191900 A
Classification (IPC)G01R29/08 +1 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedApril 15, 1983Patent grantedAug 13, 1985Term endedAug 13, 2002

Sources & verification

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