Roof supports
CA 1136871 A · Owner: Harding, John D. · Inventors: Harding, John D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a self-advancing roof supporting apparatus for providing temporary support of a portion of the roof of a tunnel, for example in an underground mine such as a coal mine. When tunnels are being extended, temporary roof supports need to be erected whilst the newly excavated material is removed and permanent roof supports installed. The apparatus of the invention has means engageable upon the permanent roof-supports to suspend the apparatus therefrom, and preferably has two relatively slidable gripping devices (5) or sets of devices to enable the apparatus to be advanced or withdrawn along the tunnel. - 1 -
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
- Granted December 7, 1982. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 7, 1999.
- 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.