Composite filled hollow structure
CA 2252841 C · Owner: Greene, Robert H. · Inventors: Greene, Robert H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A filled structure includes a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi and an inside surface forming a boundary which encloses a space. A hard core is provided within the space enclosed by the hollow structure. The hard core has a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi. The hard core is formed from a mixture of particulate cementitious material and liquid. The filled structure is constructed and arranged such that the hard core is locked to the inside surface of the hollow structure by mechanical bond or chemical lock or stressed expansion.
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 19, 1997 and granted February 18, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 19, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 19, 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.