Water lock method and apparatus
CA 2061844 C · Owner: Kelly, James A. · Inventors: Kelly, James A.; Westhoff, James A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A watertight chimney assembly prevents infiltration of water in the region between a manhole cover support frame and a concrete manhole assembly. The watertight chimney is comprised of a pair of telescoping sleeves each provided with a flange for mounting respectively to the top lip of a manhole assembly and the bottom surface of the flange on the cover frame a desired distance above the top of the manhole assembly to maintain the cover frame at proper grade. An O-ring seated within an annular groove provided in one of the tubular members provides a sliding watertight seal therebetween. The sleeve flanges are compressed between the frame and manhole assembly and contribute to 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 February 25, 1992 and granted April 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 25, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 25, 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.