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Expired Canadian patentCanada

Acoustical transformer for horn-type loudspeaker

CA 1085504 A · Owner: Altec Corporation · Inventors: Henricksen, Clifford A.

CIPO record

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

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Abstract From the Canadian patent

An acoustical transformer or "phasing plug" for coupling sound from a speaker diaphragm to the throat of a horn. The phasing plug of the invention is in the general shape of a dome on one side and a truncated cone on the other and has evenly, spaced radial slots or channels formed therein these slots, forming air passageways for propagation of the soundwaves. The walls of the slots are tapered exponentially from their inlet ends at the speaker diaphragm towards a flat plane outlet at the throat of the horn, to provide an optimum impedance match between the output of the diaphragm and the input of the horn; the sound channels formed by the slots exponentially increasing in area between their …

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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 September 9, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 9, 1997.
  • 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 7, 1977
GrantedSeptember 9, 1980
Term endedSeptember 9, 1997
Patent numberCA 1085504 A
Classification (IPC)H04R1/30

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedJuly 7, 1977Patent grantedSep 9, 1980Term endedSep 9, 1997

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