Cigarette filter
CA 1289433 C · Owner: Mcmurtrie, Andrew · Inventors: Lamb, Charles G.; Mcmurtrie, Andrew
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 porous filter rod circumscribed by a substantially non-porous or air impermeable wrapper with selected air permeable areas and ventilating air, grooves embedded in the wrapped filter rod which extend from one end of the filter rod a preselected distance generally longitudinally of the filter rod. Tipping material circumscribes the wrapped filter rod and is formed with perforations therethrough providing a path for ventilating air flow into the grooves and into the body of the filter rod at the selected air permeable areas outside of the grooves. The walls of each of the grooves are formed with preselected perforations therethrough to provide for the flow …
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 September 24, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 24, 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.
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.