Apparatus for correcting irregularities in or enlarging an underground duct
CA 1293207 C · Owner: I.P.D. Systems Limited · Inventors: Yarnell, Ian Roland
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Novel apparatus is provided herein for travelling through an underground duct and for removing irregularities in or, enlarging, the duct. The novel apparatus includes two sets of expandable segmented shell portions arranged one in front of the other along a longitudinal axis of the apparatus. The shell portions are arranged around the longitudinal axis and have respective outwardly-facing outer surface portions for engaging the sides of the duct. The shell portions are movable laterally with respect to the longitudinal axis from a contracted configuration to an expanded configuration for forcing the sides of the duct away from the axis. The shell portions of the first set each are pivotally …
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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
- Granted December 17, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 17, 2008.
- 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.