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Expired Canadian patentCanada

Magnetic apparatus

CA 1232039 A · Owner: Sony Corporation · Inventors: Ito, Seigo; Murakami, Yoshikazu

CIPO record

Overview

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

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Abstract From the Canadian patent

Disclosed herein is a magnetic apparatus comprising: a magnetic circuit including magnetic yoke and a magnet, with a magnetic gap formed in the circuit for forming a uniform d.c. bias magnetic field in the magnetic gap; a magnetic device made of magnetic material of certain composition and placed in the magnetic gap so that the device operates in the d.c. bias magnetic field; and a soft magnetic plate provided in the magnetic gap, the soft magnetic plate being made of magnetic material having composition substantially identical to the composition of the magnetic device.

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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 January 26, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 26, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 27, 1985
GrantedJanuary 26, 1988
Term endedJanuary 26, 2005
Patent numberCA 1232039 A
Classification (IPC)H01P1/21 +1 more

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedFeb 27, 1985Patent grantedJan 26, 1988Term endedJan 26, 2005

Sources & verification

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