Apparatus for forming porous preform used to fabricate optical fiber
CA 2076737 C · Owner: Yagi, Takeshi · Inventors: Koinuma, Yoshiaki; Satou, Tsuguo; Yoshida, Kazuaki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus for forming a porous preform used to fabricate optical fiber by extruding a plastifiable material containing silica powder as its main component the apparatus including an extruding main body having a cylinder and a screw for extruding the plastifiable material from the cylinder, a material passage member connected to the cylinder so as to communicate therewith and having a rotation stopping member, and a molding head connected to the material passage member so as to communicate therewith.
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 August 24, 1992 and granted September 30, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 24, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 24, 2014.
- 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.