Patent Yard Sign in
Expired Canadian patentCanada

Diaphragm for loudspeakers

CA 1291558 C · Owner: Saiki, Shuji · Inventors: Takayama, Satoshi; Murata, Kousaku; Tanaka, Tsuneo

CIPO record

Overview

Drawings and full text

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

Open the CIPO record

Abstract From the Canadian patent

A diaphragm for loudspeakers comprises chitin as a natural high polymeric material having a large value of Young's modulus and kraft pulp having large mechanical internal loss. Therefore, the deformation and the partial vibrations of the diaphragm during diaphragm operation do not come out due to the use of the chitin because the, flexural rigidity of the diaphragm is considerably large. Mechanical internal loss is also large owing to the use of the kraft pulp. As a result, it is possible to obtain a loudspeaker which has little fluctuation in frequency response, and which provides a superior sound pressure-frequency response, a superior distortion factor and a superior phase response.

Read the whole patent

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 29, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 29, 2008.
  • 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 31, 1987
GrantedOctober 29, 1991
Term endedOctober 29, 2008
Patent numberCA 1291558 C
Classification (IPC)H04R7/02

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedJuly 31, 1987Patent grantedOct 29, 1991Term endedOct 29, 2008

Sources & verification

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