Abstract: The support assembly is made up of a floor-standing runner member 1, a hydraulically vertically-adjustable prop 2 mounted on the same, a roof canopy 3 supported by the same and a rockfall shield 4 hinged to the same on the backfill side which is guided to be pivotable in a vertical plane by two direction-control members 5 and 6 articulated to the runner member so as to be spaced apart one behind the other. The front direction-control member 6 is constructed as a hydraulic thrust piston mechanism. Via a control circuit 8 the hydraulic control valve 7 of the direction-control member 6 is connected to measuring devices 9 usable to measure the position of at least two mutually variably spaced apart support assembly reference points. If the reference points deviate from the preset normal position of the support assembly, pressure fluid acts on the front direction-control member 6 via the control circuit 8 until the normal position has been regained.

Abstract: A control line connects an annular space in an auxiliary hydraulic cylinder of an hydraulically-movable mine-roof support (the auxiliary cylinder being provided to advance a forward, auxiliary, roof-support canopy in the direction of the working face of a mine) to the displacement space of an hydraulic measuring cylinder which is longitudinally displaceable in a direction parallel to the hydraulic advancing cylinder in order to advance the auxiliary roof-support canopy, which is pivoted to the main roof-support canopy, in synchronism with the advancing cylinder mounted in the base of the mine-roof support and attached to an abutment on the working face side of the support. A control valve is connected to the control line and responds to the control line pressure in such a way that, when the pressure falls, it supplies pressurized fluid into the pressure space of the auxiliary cylinder to extend the piston rod thereof, and shuts off again when the pressure increases.

Abstract: A self-advancing mine roof support has a beam-like abutment adapted to be disposed generally adjacent and parallel to a work face. Three roof support elements are spaced apart along the abutment and are pivoted to the abutment. The abutment may be angled relative to the direction of advance by arranging the three support elements in staggered formation. A beam of the central support element is pivoted to the abutment. The two outer roof support elements are connected to the abutment by a linkage, e.g., guide arms, which allows the abutment to pivot about the beam of the central element without changing the distance between the three elements as measured at right angles to the direction of advance.

Abstract: The invention is concerned with a hydraulic shield-type support for supporting roofs in mines comprising a pair of base slides between which is located a channel-section guide beam supporting an hydraulic ram. At the rear end of the hydraulic ram a yoke is pivotally connected at a central part thereof to the rear end of the guide beam, the two outer portions of the yoke being pivotally connected to the rear end portions of the base slides. The front extendable end of the ram is connected to an elongate flat tongue which is longitudinally slidable in the guide beam underneath the hydraulic ram.

Abstract: The roof-engaging assembly of a support frame for a mine roof comprises a main beam having a cantilever extension pivoted to the main beam by pins. In order to pivot the cantilever extension through an angle of about 180.degree.-200.degree. between a stowed position and an operative position, a link is pivoted at one point to the main beam and is pivoted at another point to one end of a double acting jack. The other end of the jack is pivoted to the main beam so that, by extending or retracting the jack, the link member pivots one way or the other. The cantilever extension has a pin which runs in a slot in the link member, the arrangement being such that pivoting of the link member by the jack produces pivoting of the cantilever extension through a much larger angle, e.g., double the angle.

Abstract: A walking mine-roof support comprising two roof support units which are to be moved with respect to one another for advancing the support, each of the units including a pair of spaced-apart frames each comprising a pair of hydraulically-extensible props disposed one at each side of the frame connected to a cross-member extending between the props, the two frames of each unit being interconnected by roof-supporting bars connected to the cross-members of the frames, the two roof support units overlapping one another in the direction of advance of the support so that first and third frames form a leading one of the units and second and fourth frames form the other unit which is a trailing unit, the two frames of one unit being connected to a frame of the other unit disposed between the two frames by respective first and second rams, whereby during relative movement between the units one of the rams is extended while the other retracts.

Abstract: A control device serves to control the fluid flow to and from double-acting rams, especially the rams of mining machinery, the control device having various internal ducts which are defined between two plates connected together. One of the two plates (a duct plate) has a main face formed with channels, some of which radiate outwardly from a ring of bores, and two of which are `T`-shaped and extend generally tangential to the ring of bores. The other plate (a connecting plate) closes the channels to define ducts and has bores communicating with the various ducts. Control valve units are detachably connected to the connecting plate, the control valve units being arranged to be actuated to effect desired connections between the various ducts by way of the bores in the connecting plate.

Abstract: A control device for controlling hydraulically actuated equipment, the device comprising a fluid distributing block and a plurality of control valve units detachably mounted side-by-side on the block, the block being formed with an inlet opening, an outlet opening, a plurality of control line openings, a plurality of delivery openings, a plurality of return openings, a plurality of valve unit communicating openings, and internal passage means, the said internal passage means connecting the inlet opening with each of the delivery openings, connecting the outlet opening with each of the return openings, and connecting the control line opening with respective corresponding ones of the valve unit communicating openings.

Abstract: A hydraulic, walking, roof-support frame comprising a vertically-movable, pivotable control lever pivotally connected at its lower end portion to a rigid inextensible rocker arm pivotally mounted on a floor runner or skid of the frame and guided at a distance therefrom by a second rocker arm disposed nearer the coal-face end of the frame and pivotally connected to the floor runner and to the control lever, the free or coal-face end of the control lever being pivotally connected to a roof bar or plate pivotably born by hydraulic vertically-adjustable props, in which the said second rocker arm is longitudinally adjustable and is so constructed that it can be held at a predetermined intermediate length between pivots at its ends to enable its length to be changed in either direction as a result of a thrust from the roof.

Abstract: An hydraulic walking roof-support frame for a coal mine has a roof support assembly comprising a main support and an auxiliary support pivotally connected to the main support for pivoting about a horizontal axis through an angle of 180.degree.. The auxiliary support is caused to pivot by a pair of hydraulically operated extensible and retractable jacks connected between the main support and the auxiliary support, the pivot points where the jacks are connected to the auxiliary support being angularly spaced apart relative to the axis of pivoting of the auxiliary support whereby when (during pivoting of the auxiliary support) one jack is in a "dead center" position the other jack can still pivot the auxiliary support permitting remote control thereof.