Mine roof supporting

The method of providing roof support for a coal mine or the like with bolts, the said method being practiced with apparatus including an elongated bar of resilient material and drive means connected to said bar for vibrating said bar at a sonic frequency in the bending mode of said bar, thus producing a standing wave along said bar by supports, below said roof, engaging said bar at the node positions of said standing wave, with the vibrational movement said bar upwardly towards said roof and downwardly away from said roof, mountng a said bolt on the bar at an anti-node position of said bar, said bolt extending vertically upwardly towards said roof from said anti-node position, setting said bar vertically so that said bolt engages said roof, actuating said drive means to vibrate said bar and thus causing said bolt to penetrate directly into said roof, during the upward movement of said bar and exerting a vertical force upwardly on said bar to maintain said bolt continuously in pressure engagement with said roof under the action of said force until said bolt is driven into said roof.

Apparatus for providing roof support for a coal mine or the like by driving bolts into said roof, the said apparatus including an elongated bar of resilient material, drive means, connected to said bar, for vibrating said bar at a sonic frequency in the bending mode of said bar, thus producing a standing wave, have nodes and anti-nodes along said bar, means supporting said bar at said nodes, means connecting a said bolt to said bar near an anti-node position therealong, said bolt being connected vertically to said bar to engage, and be driven into said roof, said connecting means including a hammer actuable by the vibration of said bar and a vertical guide for said hammer, said bolt being removably secured to said hammer, and means, connected to said bar, exerting a force to maintain said bolt in continuous engagement under force with said roof as said bolt is being driven therein by the vibration of said bar.