Lightweight prestressed tower
CA 2211807 C · Owner: Crissey, Glenn C. · Inventors: Crissey, Glenn C.; Crissey, Merrill E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A lightweight, prestressed tower includes 1) a base load transfer assembly to be mounted on a support base fixture assembly which is mounted on a base support pad; 2) a primary truss assembly consisting of a plurality of truss bays interconnected by diagonal and vertical tension members between horizontal frame assemblies; 3) a central compression tube assembly operable to be extended centrally of the truss bays from bottom to top having tubular sections connectable to each other to provide a central compression load assembly; and 4) an upper load transfer assembly connected to an upper end of the central compression tube assembly and by horizontal and diagonal tension members of the …
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 21, 1997 and granted July 27, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 21, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 21, 2019.
- 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.