Single cavity automobile muffler
CA 2039745 C · Owner: Noise Cancellation Technologies, Inc. · Inventors: Cain, John J.; Dye, David; Barnes, Dennis
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A noise suppression system for use on internal combustion engines and small enough for use in automotive applications is disclosed. A cancellation noise generator and actuator speakers produce a noise to combine with and cancel the engine noise carried in exhaust gases in a mixing chamber. The resultant noise leaving the mixing chamber is measured by a circulr tubular microphone array to control the noise generator.
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
- Filed April 4, 1991 and granted June 12, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 4, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 4, 2013.
- 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.