Abstract: A mine roof support has a main roof bar which is pivotably connected to an auxiliary forwardly-extendible bar. At least one piston and cylinder unit serves to swing the auxiliary bar about the main bar to bring the auxiliary bar into a roof-contacting position aligned with the main bar or into a stowed position beneath the main bar or into some intermediate position. One or more pivotable guide levers connect the auxiliary bar to the piston and cylinder unit. A guide member is also connected to the unit and slidably locates in longitudinal guideways formed in ribs or the like at the underside of the main roof bar.

Abstract: A mineral mining installation includes a longwall conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. The conveyor is braced longitudinally by a block bracing system having a plurality of hydraulic bracing rams each of which is disposed at an acute angle to the conveyor. The bracing rams act between the conveyor and floor girders of the roof support units. Each bracing ram is attached to a respective floor girder by means of a bracket. Each bracket has first and second bracket parts welded together, the first bracket part comprising means for connecting the bracket to its floor girder, and the second bracket part forming an extension of the first bracket part and carrying a pivot joint member for pivotally supporting the cylinder of the associated bracing ram. The first bracket part is a standard cast member, to which second bracket parts of differing lengths can be welded.

Abstract: A mineral mining installation comprises a mine roof support assembly and apparatus for drilling bores. The roof support assembly comprises a plurality of roof support units positioned side-by-side, and the drilling apparatus comprises a drilling device which is movably guided on a track associated with the roof support assembly. Each of the roof support units has at least one roof bar. The track is arranged on the underneath sides of the roof bars of the roof support units. The drilling device is pivotally mounted on a trolley which is movably guided on the track.

Abstract: A mine roof support unit has a mechanism for adjusting the angular position of an auxiliary cap relative to a main cap, the auxiliary cap and the main cap forming the roof cap of the mine roof support unit. The auxiliary cap is connected to the main cap by a first pivot joint. The cap-positioning mechanism comprises a hydraulic ram and a lever acting between the main cap and the auxiliary cap. The auxiliary cap is provided with an extension arm projecting from the first pivot joint towards the main cap. One end portion of the lever is connected to the arm by a second pivot joint, and the other end of the lever is connected to a block attached to the piston rod of the ram by a third pivot joint. The cylinder of the ram is attached to the main cap.

Abstract: A machine frame for a scraper-chain conveyor employs a housing or `plough box` containing a chain wheel for driving a haulage chain. A stripper device is provided in the housing to separate the chain from the chain wheel. The stripper device is composed of a one-piece shaped element with an arcuate blade projecting into the chain wheel. The element is fitted to a mounting flange of the housing with a single upstanding bolt-and-nut and a separate complementary locking member. The element, the locking member and the flange have shape-locking interengaging projections and recesses. The device can be positionally inverted.

Abstract: A channel section for a scraper-chain conveyor is constituted by a pair of sigma-shaped side walls, and a floor plate welded to the central flanges of the side walls. The sigma-shape of the side walls define V-shaped grooves in the side walls, each of these grooves being defined by a pair of outwardly-divergent inclined wall portions. Each end zone of each side wall is provided with a coupling element for coupling the channel section to an adjacent similar channel section. Each of the coupling elements is welded into a cut-away part formed at the adjacent end zone of the respective inclined wall portions. The coupling elements are provided with recesses for the reception of a connector such as a toggle bolt connector. Each of the side walls is provided with elongate stiffening members welded thereto adjacent to the upper and lower flanges respectively. The coupling elements protrude outwardly beyond their side walls as far as the outer edges of the stiffening members.

Abstract: A mine roof support unit has a floor sill, a roof cap supported above the floor sill by a pair of inclined hydraulic props, and control apparatus for controlling load-bearing capacity of the props. The inclination of the props relative to the vertical increases as the props are retracted. The control apparatus comprises a pressure-relief valve for limiting the pressure of the hydraulic fluid supplied to the hydraulic props. The pressure-relief valve has a closure member which is biased towards its closed position by a spring. The spring is backed by an abutment member which constitutes a setting device for adjusting the biasing force of the spring, thereby controlling the operating pressure of the pressure-relief valve, and hence the load-bearing capacity of the props.

Abstract: A roof support unit for a longwall mineral mining installation has a roof shield supported above a floor sill. A first hydraulic ram is provided for advancing the roof support unit. The roof shield is provided with a forward extension which is advanceable by means of a second hydraulic advance ram. A hydraulic control arrangement, which includes the two hydraulic advance rams is provided for controlling the advance of the roof shield extension in dependence upon the working stroke of the first hydraulic advance ram. The control arrangement is such that the amount of hydraulic fluid supplied to one of the pressure chambers of the second hydraulic advance ram is dependent upon the amount of hydraulic fluid expelled from one of the pressure chambers of the first hydraulic advance ram during the working stroke of the first hydraulic advance ram.

Abstract: A tunnel knife shield has a support frame, and a plurality of knife positioned side-by-side on the support frame. Each of the knives is associated with a double-acting hydraulic ram, the rams being used for advancing the knives, and for causing the support frame to follow up the advance of the knives. Hydraulic control means are provided for controlling the extension and retraction of the rams. Each ram has first and second working chambers, pressurization of which is effective to extend and retract that ram. The hydraulic control means comprises a plurality of control valves, each of which is associated with a respective hydraulic ram. Each control valve is provided with a first input constituted by a separate first hydraulic line. Each control valve is also provided with a second input, which is constituted by a common second hydraulic line. The common second hydraulic line is fed with hydraulic fluid by all of the first hydraulic lines.

Abstract: A cutting device for a mining or tunnelling machine takes the form of a roller with cutter bits which rotates at the end of a movable arm as is known. Grooves in the roller receive plate-like components which support water spray nozzles radially within the extremities of the cutter bits. The support components are stationary but are adjustable about the axis of rotation of the roller to bring the nozzles into the appropriate location during operation.

Abstract: A drive frame for a scraper-chain conveyor comprises a pair of generally parallel side plates. A pair of aligned bearing bushes rotatably support a drive shaft of a chain drum. The bearing bushes are mounted in apertures in the side plates. The bearing bushes are welded to their respective side plates, thereby strengthening the drive frame.

Abstract: Apparatus for use in driving tunnels or the like comprises a front drive shield composed, for example, of elongate cutter knives supported for longitudinal displacement on a frame. In order to control turning motion of the shield the shield is connected via hydraulic control rams to a rear abutment such as a follow-up ring structure. The rams are all inclined relative to the longitudinal axis of the apparatus. The rams are divided into two groups inclined in opposite directions and the rams of each group can be subjected collectively to pressure fluid to impart a corrective torque to the frame.

Abstract: A longwall mineral mining installation has a conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. Each roof support unit has a roof shield having an advanceable shield extension. Each unit has a first hydraulic ram for extending its shield extension, and a second hydraulic ram for advancing the conveyor. The extension of each first ram is controlled in dependence upon the retraction of one of the second rams (either the second ram of the same unit or that of an adjacent unit). This control is effected by controlling the supply of pressurized hydraulic fluid to the first rams. In one embodiment this is carried out by a control valve which has a spring-loaded plunger which engages with a series of equispaced cams on the movable cylinder of the associated second ram. In another embodiment, the piston rods of the rams are provided with series of equispaced magnets.

Abstract: A mine roof support has hydraulic props mounted between a floor sill and a roof bar which can be raised and lowered by extension and retraction of the props. A goaf shield is pivotably connected to the rear of the roof bar and is linked via levers to the floor sill. A hydraulic piston and cylinder unit is connected between the roof bar and the goaf shield. Apparatus serves to prevent damage to the support components, and especially to the unit which could be extended beyond its full stroke when the props are retracted to bring the goaf shield and the roof bar more or less into alignment. The protective apparatus is composed of a compact valve device operated by a member, such as a cam, to block the props from hydraulic pressure when the goaf shield and the roof bar assume a pre-determined angular disposition. Both the valve device and its operating member are disposed in a protected position within chambers formed inside the roof bar and the goaf shield adjacent the pivot connection therebetween.

Abstract: A scraper-chain conveyor has channel-sections or pans arranged end-to-end along which a scraper-chain assembly is circulated. Each pan is composed of rolled side walls with a floor plate welded therebetween. The side walls are reinforced by upper and lower elongate bars welded to their exteriors. These bars have shaped apertures designed to accept and locate the heads and shanks of bolts used to fix attachments to the side walls. The side walls are recessed behind the apertures and these recesses define with the apertures, pockets for receiving the heads of the bolts.

Abstract: A mineral mining installation serves to win mineral by explosive blasting. The installation employs a shuttle conveyor arranged alongside a mineral face. Roof supports stand side-by-side at the side of the conveyor remote from the conveyor. The roof supports are connected to the conveyor through shifting rams and have roof-engageable caps or the like supported on hydraulic props. The pans of the conveyor have upstanding walls at the rear side nearest the roof supports which carry rails at their upper ends. The roof caps have wall components pivoted thereto and hydraulic piston and cylinder units serve to swing the wall components up and down. When explosive blasting takes place the wall components are swung down to engage on the walls of the conveyor pans to form a screen between the winning region and the access region of the working.

Abstract: A tunnel knife shield has a support frame, and a plurality of knives positioned side-by-side on the support frame. Each of the knives is associated with a double-acting hydraulic ram, the rams being used for advancing the knives, and for causing the support frame to follow up the advance of the knives. Hydraulic control means are provided for controlling the extension and retraction of the rams. Each ram has first and second working chambers, pressurization of which is effective to extend and retract that ram. The hydraulic control means comprises respective first supply lines for supplying pressurized hydraulic fluid to the first working chambers, respective second supply lines for supplying pressurized hydraulic fluid to the second working chambers, and respective discharge lines for discharging hydraulic fluid from the first working chambers. Each discharge line is provided with a flow-regulation valve and a pilot-operated non-return valve.

Abstract: A mineral winning plough, such as a coal plough, has a plough body adapted to be moved to and fro alongside a mineral face on a plough guide. The plough body is provided with a pair of vertically-adjustable carriers, each of which is provided with floor cutters. The plough body is provided with setting means for raising and lowering the carriers into rest and working positions respectively. The setting means comprises a slide plate, and an intermediate member. The slide plate is mounted in an aperture in the plough body for limited movement relative thereto. The slide plate is attachable to a plough drive chain. The intermediate member forms a mechanical operative connection between the slide plate and the two carriers. The intermediate member is rotatably mounted on the plough body, and is positioned between the two carriers.

Abstract: A mineral mining installation comprises a longwall conveyor, and a plurality of roof support units positioned side-by-side along the goaf side of the conveyor. The roof support units are positioned to define an access area between the conveyor and the roof support units. A plurality of hydraulic bracing rams act on the conveyor to brace the conveyor longitudinally. Each of the bracing rams is pivotally attached to a floor sill of a respective roof support unit. The hydraulic bracing rams are positioned at the goaf-side edge portion of the access area. The bracing forces are transmitted from the bracing rams to the conveyor via respective transverse arms attached to the bracing rams and to the conveyor.

Abstract: A mine roof support unit is constituted by two detachably connected parts. Each of the parts has a floor girder which supports a roof bar by means of a hydraulic prop. The roof support unit is intended for use at the lower end of an inclined longwall working which meets its access gallery at an angle other than 90.degree.. The detachability of the two parts enables one of these parts to be removed from the working as its face is advanced. The removed part can then be transported to the other end of the working. Each of the parts is provided with means for detachably connecting an advance mechanism.