Mine roof supports

Abstract

The invention is concerned with a self-advancing mine roof support comprising a base, hydraulically extensible prop means mounted on said base and a roof-engaging structure, including a canopy, mounted on said prop means for application thereby to a roof to be supported. On at least one side of the roof support there is a laterally extensible and retractable auxiliary canopy and a device is provided for urging and extending said auxiliary canopy laterally outwardly with respect to the support. The auxiliary canopy on the support bears firmly against a similar auxiliary canopy on an abutment on a neighboring roof support so as to prevent roof material falling between the two supports. Because it is retractable, however, the auxiliary canopy does not interfere with the advance of the supports. Conveniently the auxiliary canopy comprises two box-like members fitted telescopically one within the other. The device for urging and extending the auxiliary canopy laterally may be a pressure-fluid ram, and valve means controlling the pressure-fluid flow of said ram may be incorporated in the pressure-fluid system of a pressure-fluid advancing means for the support so that said ram is automatically retracted or put on open circuit before said advancing means becomes operative to advance the support.

Dependencies are inferred from the claim text.