Abstract: A mine roof support employs a pair of floor skids carrying hydraulic props on which a roof-engaging structure is mounted. A goaf-shield is pivotably mounted to the roof-engaging structure and is connected with a lever system to the floor skids. A shifting and guide mechanism is disposed between the floor skids and takes the form of an hydraulic ram connected at the rear to a floor rail disposed beneath the ram. The ram is supported at the front end by a bridge member connecting the front ends of the skids together. An hydraulic lifting unit is mounted on the bridge member and when extended the unit bears on the floor rail to partially lift the skids as the shifting ram is operated. The lifting unit can be mounted to the bridge member in one of several alternative height positions.

Abstract: A mine roof support frame has a pair of spaced-apart floor skids on which hydraulic props support a roof engaging structure. A shifting mechanism with a ram in a trough-like housing and a guide beam is positioned between the skids and serves to displace the frame relative to a scraper-chain conveyor and vice versa. The guide beam is a flat plate with a width more or less the same as the space between the skids and rests directly on the floor. The piston rod of the ram is coupled to the guide beam near the conveyor, the ram cylinder is coupled to the housing and the housing is coupled to the skids at the stowage end. The ram housing has a guide rail on the underside which mates with a guide element on the top of the guide beam. Levers pivotably coupled to the floor sills in front of the ram housing are operated by piston and cylinder units to engage on the guide beam to lift the floor skids partially during advancement of the frame.

Abstract: A longwall mineral mining installation has a longwall conveyor and a plurality of roof support units positioned side-by-side at the goaf side of the conveyor. The hydraulic appliances of the roof support units, such as their hydraulic props, hydraulic advance rams and hydraulic control valves, are supplied with pressurized hydraulic fluid from hydraulic supply lines which run along the goaf side of the conveyor. A plurality of flat, plate-like intermediate members are provided at the goaf side of the conveyor. These intermediate members are formed with internal ducts for feeding the hydraulic fluid from the supply lines to the hydraulic appliances of the roof support units.

Abstract: A support assembly for a mine working has a floor-sill structure for engaging on the floor of the working and a roof-engaging member or members braced by one or more props against the roof of the working. The floor-sill structure employs one or more slidable skids which can be selectively extended in length at the forward end by fitting an extension component of the same width thereto. The or each skid is recessed to receive rear projections of the associated extension component and securing means, such as spindles or shaped locking elements, are used to secure the extension component to the skid. When the extension component is removed, inserts are located in the recesses of the skid to fill the latter and these inserts can be likewise secured with the same securing means.

Abstract: A releasable pivot joint for use in underground mining installations comprises first and second connecting members. The first connection member has a width which is greater than its thickness and a reduced portion that reduces its width to a core width. The second connection member is formed with a slot into which is inserted the reduced portion of the first connection member. The width of the slot is greater than the thickness and the core width of the first connection member. The length of the slot is greater than the width of the first connection member. The thickness of the second connection member is smaller than the core width of the first connection member. The width of the first connection member extends transversely of the length of the slot when the connection members are in the connected position.

Abstract: A roof support unit for use in a mineral mining working has a roof shield supported on a floor sill by means of at least two hydraulic props. A goaf shield is pivotally linked to both the roof shield and the floor sill. At least one of the hydraulic props is inclined towards the face-side of the unit and engages the roof shield. At least one of the hydraulic props is inclined towards the goaf-side of the unit and engages the roof shield.

Abstract: The invention relates to an advance mechanism for a roof support assembly constituted by a plurality of roof support units positioned side-by-side along, for example, a longwall face of a mineral mining working. The advance mechanism comprises a pair of hydraulic advance rams and a pair of resilient, generally parallel guide rods. The guide rods are interconnected at one end by means of a head-piece which is attachable to a conveyor extending along the longwall face. The other end of each guide rod is attached to a respective slide piece which is slidably guided on a respective guide rail which is attached to a floor girder of a roof support unit. The hydraulic advance rams are each pivotally attached to one of the slide pieces and to one of said floor girders. The guide rods are provided, adjacent said one end, with outwardly projecting alignment members each of which co-operates with one of said floor girders to align an associated roof support unit during its advance.

Abstract: The invention relates to an advance mechanism for a roof support unit to be used in a longwall face of a mineral mining working. The advance mechanism comprises a hydraulic advance ram and guide means constituted by a guide rod means and a guide rail. One end of the guide rod means is attached to a conveyor extending along the longwall face, the other end of the guide rod means being attached to a guide element. The guide rail extends slidably through a guide aperture in the guide element and is pivotally attached to the floor sill of the roof support unit for pivotal movement in a vertical plane perpendicular to the longwall face. The hydraulic advance ram is attached to the guide element and acts on a member fixed to the floor sill.

Abstract: A shield-type support assembly for a mine working is composed of three substantially identical frames aligned side-by-side. Each frame has a floor sill structure which carries props capable of bracing a roof cap and the floor sill structure between the roof and floor of a mine working. A goaf shield is provided for each frame and these shields combine to screen off the goaf zone. The outer frames on the one hand and the central frame on the other are shiftable in alternation with the aid of shifting rams. One or more transverse arms extend across the forward regions of the frames and the or each arm is carried by the central frame floor sill structure. Guide devices are connected to the arm or arms and serve to guide the frames when shifted by the rams and the rams themselves transmit the shifting or reaction forces to the arm or arms.The coupling between the floor sill structures of the frames permits relative vertical mobility therebetween to cope with variations in the floor level of the working.

Abstract: A mine support assembly is composed of separate floor-engaging sills each supporting one or more telescopic props and a goaf shield pivotably connected to a roof cap. The props can be extended or retracted to raise or lower the roof cap. The shield is divided into a common upper section and lower parts each pivotably connected to the upper section and to a respective associated one of the floor sills. Levers are pivotably connected between the sills and the upper section of the goaf shield and serve with the lower shield parts as a guide means ensuring the roof cap is raised or lowered without appreciable horizontal displacement. The floor sills and lower shield parts are respectively spaced apart and a shifting ram is connected to the floor sills via a transverse yoke pivotably connected to the forward end regions of the sills.

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.

Abstract: The invention relates to an advance mechanism for a roof support assembly constituted by a plurality of roof support units positioned side-by-side along, for example, a longwall face of a mineral mining working. The advance mechanism comprises a pair of hydraulic advance rams and a pair of resilient, generally parallel guide rods. The guide rods are interconnected at one end by means of a head-piece which is attachable to a conveyor extending along the longwall face. The other end of each guide rod is attached to a respective slide piece which is slidably guided on a respective guide rail which is attached to a floor girder of a roof support unit. The hydraulic advance rams are each pivotally attached to one of the slide pieces and to one of said floor girders. The guide rods are provided, adjacent said one end, with outwardly projecting alignment members each of which co-operates with one of said floor girders to align an associated roof support unit during its advance.