Cigarette filter
CA 1198647 A · Owner: Brown & Williamson Tobacco Corporation · Inventors: Lamb, Charles G.; Sanford, Robert A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A filter for a cigarette includes a generally cylindrical permeable filter sod circumscribed by an air permeable tipping material with a plurality of blind-end channels formed in the filter rod, each of the channels being open at one end to the upstream end of the filter rod and extending therefrom, generally in the longitudinal direction of the filter rod, a predetermined distance less than the length of the filter rod.
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 December 31, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 31, 2002.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.