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Expired European patentEurope

Sound reproduction systems

EP 0046765 B1 · Applicant: NATIONAL RESEARCH DEVELOPMENT CORPORATION

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed February 12, 1981 and granted December 7, 1983. A European patent lasts at most 20 years from filing, so its term ended February 12, 2001.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by August 12, 2006.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledFebruary 12, 1981
PublishedMarch 10, 1982
GrantedDecember 7, 1983
Term endedFebruary 12, 2001
Application numberEP 81900334
Classification (CPC)H04S3/02

Timeline

Timeline From EPO dates

1982198419861988199019921994199619982000Application filedFeb 12, 1981PublishedMarch 10, 1982Patent grantedDec 7, 1983Term endedFeb 12, 2001

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.