Abstract: A shut-off fitting with a sealing device consisting of a packing casing and a packing gland for the actuation element of the valve has the packing casing including bores that hold the sealing elements. The packing has at least one grooved metal ring with an elastic ring seal on the side facing the actuation element and the bore. As a seat for an elastic ring seal the packing gland features an oblique shoulder which descends toward the center, whereby the ring seal bears the pressure conveyed by a ring element and produced by a spring in the longitudinal direction of the axis of the actuation element.

Abstract: A mine roof support has a roof-engaging frame structure supported by hydraulic props on a floor frame and pivotably linked to a goaf shield. The roof frame and goaf shield have L-shaped seal plates at their sides. The seal plates are subjected to a lateral-outwardly-biasing spring force by means of springs and push rods accommodated in guide bores in both the roof frame and goaf shield. To adjust the distance between the plates, there are piston and cylinder units and coupling rods likewise accommodated in guide bores in both the roof frame and goaf shield. The seal plates of the roof frame overlap with those of the goaf shield. The plates are reduced in thickness at their overlapping regions and are pivotably interconnected thereat to correspond to the pivotal connection between the roof frame and the goaf shield. To facilitate assembly in situ, detachable push-in pins are located in bores in the coupling rods and push rods and in lower transverse walls of both the roof frame and goaf-shield.

Abstract: A ball-and-socket type connection particularly intended for interconnecting a prop and a roof bar or floor rail of a mine roof support assembly. The connection has a socket formed on the bar or rail and a ball part formed on the prop. The socket part has a curvilinear inner wall portion which receives the ball part and a rectilinear frusto-conical outer wall portion which widens outwardly of the socket part to form a mouth. The ball part has a bore or recesses which receives a securing means which may be a onepiece or multi-part elongate structure. The securing means extends into the socket part to engage with the bore or recesses in the socket part and lies alongside the outer wall portion of the socket part. The securing means is detachably connected to the bar or rail in a position readily accessible from the side adjoining the mouth of the socket part when the connection is in use.