GB1433631A - Multi-component roof support for a self-advancing roof control system at longwall faces in mines - Google Patents

Abstract

1433631 Advancing mine roof support systems BOCHUMER EISENHUTTE HEITZMAN & CO 22 May 1973 [24 May 1972 27 Dec 1972] 24492/73 Heading E1P A roof support 1 for a longwall face comprises at least one advancing unit 11, 12, 13 and at least one like, double-acting piston- and-cylinder unit for operating one or more moveable components of the roof support, said units being connected either individually or in predetermined groups to a pressure supply line P and to a return line R by a common control valve 2 comprising in turn a valve body with a cylindrical bore which is connected to the posts of the units via radial connections equidistantly spaced around the circumference of an annular clearance gap which communicates with the return line through a connection in the valve body, said bore containing a rotatable valve plug having a longitudinal bore communicating through a further connection in the valve body with the supply line, one or more radial bores being in communication with said longitudinal bore to form a channel or channels between said bore and one or more of said radial connections communicating in turn with a port or ports of said units the overall arrangement being such that a given piston- and-cylinder units which are to be connected to the supply pipe via said radial and longitudinal bores are selected by rotationally positioning the valve plug and the remaining piston-and-cylinder units not so connected to the supply line are in communication with the return line when the plug has been positioned. Piston-and-cylinder units may consist of prop units 10, 10a, advancing means for forepoling roof bars or girders, means 14, 15 for actuating, cavity shields 7. The valve plug or its control member may be provided with disk stops or means to indicate when correct register has been obtained. The circuit incorporates non-return valves 56, 56a and pressure relief valves 57, 57a. For valve details and a modified valve arrangement wherein the valve plug is loaded at one end by hydraulic fluid fed thereto Figs. 2, 3 and 4 should be referred to.