Tubular retainer for mine roof expansion anchor and method of use
CA 2045355 C · Owner: Wright, Raymond L. · Inventors: Wright, Raymond L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An otherwise conventional mine roof expansion anchor of the bail-type is provided with a tubular retainer member encircling the shell leaves and having an external cross-dimension significantly (e.g. at least .10") greater than the diameter of the drill hole in which the anchor is to be installed. Thus as the, anchor, supported on the end of a roof bolt is advanced, into the drill hole in the usual manner the tubular, element is pushed off the anchor by contact with the surface surrounding the drill hole, thereby eliminating the previously required manual removal of the retainer. The tubular retainer has the same cross-sectional configuration in all planes perpendicular to its central axis …
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 June 25, 1991 and granted February 11, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 25, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 25, 2013.
- 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.