Tunnel lining
CA 1197698 A · Owner: Crs Group, Inc. · Inventors: Chase, Arthur P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A prefabricated tunnel lining is disclosed comprised of a plurality of interconnected longitudinally abutting rings each ring being comprised of a plurality of interconnected ring sections. The ring sections are each prefabricated of concrete with an internally cast steel reinforcement and have overlapping circumferential and longitudinal edges adapted to mate with corresponding edges of circumferentially adjacent sections in the same ring and longitudinally adjacent sections in longitudinally adjacent rings of the liner. Threaded fasteners extend at an angle through holes in the ring segments extending from the inside surfaces of each segment through an edge portion thereof and communi-, …
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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 December 10, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 10, 2002.
- 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.