Street manhole cover lifting device
CA 2010948 C · Owner: Prescott, Alain · Inventors: Prescott, Alain
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a street manhole defining an elongated manhole duct provided with a rigid collar at its top mouth the collar having, a radially inward annular cavity defining a base wall parallel, to the plane of the collar and a side wall orthogonal to the, base wall. The collar further defines a top wall parallel to the base wall. A spacer device is provided for raising the cover level from the collar base wall, and defines: (a) a first rigid ring, destined to sit on the collar base wall; (b) a second rigid ring, diametrally larger than the first ring and destined to sit on the collar top wall; and (c) connecting tongues for, coaxially interconnecting the rings about spaced planes the, connecting …
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 26, 1990 and granted November 17, 1992. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 26, 2012.
- 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.