Culvert extension
CA 2059261 A1 · Owner: Turner, Earl · Inventors: Turner, Earl
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Removal of beaver dams from culvert entrances in roadway and railway grades by means of blasting generally results in damage to the culvert. This invention is an extension of the culvert away from the grade by means of a hinged apparatus so that the beaver dam is built at the end of the culvert. When the dam is to be blasted the extension is placed in the raised position and the beaver dam can be blasted without damage to the culvert. The extension is then lowered back into position and pinned into place.
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 January 13, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 13, 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.