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Expired Canadian patentCanada

Tobacco smoke filter

CA 1206833 A · Owner: Mitsubishi Acetate Co. Ltd. · Inventors: Maeda, Kazuo; Sakai, Takashi; Kono, Mituo

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

A tobacco smoke filter includes a corrugated tape-like wrapping which, together with an outer perforated or otherwise air-permeable paper, defines a set of longitudinal grooves. Each of the grooves includes a blocking member, so as to inhibit direct smoke flow through the grooves and promote a ventilation effect. The blocking members in each groove are longitudinally staggered from one groove to the next to simplify the production of the 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 July 2, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 2, 2003.
  • 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 5, 1983
GrantedJuly 2, 1986
Term endedJuly 2, 2003
Patent numberCA 1206833 A
Classification (IPC)A24D3/00 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedJuly 5, 1983Patent grantedJuly 2, 1986Term endedJuly 2, 2003

Sources & verification

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