Injection moldable plastic laps
CA 2033360 C · Owner: Coburn Optical Industries, Inc. · Inventors: Rotenberg, Don H.; Whitmarsh, Milton F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A lap used for the grinding, fining and polishing of glass and plastic lenses is constructed of a one-piece injection-molded reinforced polymer body. The front surface of the lap is curved and adapted to receive an abrasive pad. The rear of the lap has a skeletal rib structure of projecting interconnected ribs. Polymers suitable for forming the lap include various crystalline polymers and copolymers having adequate chemical resistance strength, rigidity and thermal resistance.
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 December 28, 1990 and granted October 30, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 28, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 28, 2012.
- 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.