Compact disc playback enhancer
CA 2003171 A1 · Owner: Murphy, John P. · Inventors: Murphy, John P.; Murphy, John P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The playback of a compact disc is enhanced by adhering to the compact disc an annular ring to increase the frictional engagement between the disc and the spindle upon which it turns. The playback is further enhanced by adhering a layer of soft, flexible material to dampen vibrations caused by the variations in speed by which the compact disc turns.
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 November 16, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 16, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 16, 2011.
- 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.