Abstract: An electro-hydraulic control system has a valve unit allocated to a roof support (support shield, support trestle or the like) and equipped with electromagnetic valves. The unit is controlled by a control unit via a cable which includes two current supply leads serving as a common current supply for all the electromagnetic valves and at least one data bus through which an actuator connected with the valve unit is actuated from a microprocessor of the control unit. The actuator itself consists preferably of a shift register through which all the electromagnetic valves can be actuated.

Abstract: A data transmission/reception system usable for bi-directional data transmission in electro-hydraulic control systems between two adjacent supports of a mine installation which each have their own transmitting and receiving stations in a control unit. Bi-directional data exchange takes place via a single wire data bus which is used for simultaneous transmission and reception and forms the summation point for adding the transmitted signals from two transmitters. Each transmitting and receiving station is provided with a subtraction circuit connected to a receiver of the respective transmitting and receiving stations and to which the transmitted signals from its own transmitter are supplied in each case at the subtraction circuit input. The other input of the subtraction circuit is connected to the bi-directional data bus.

Abstract: A plough drive employs a plough box mounted face to face on a side plate or intermediate plate of a machine frame of a scraper-chain conveyor. A rotatable chain wheel is disposed in the box for driving a chain coupled to the plough. A chain stripper seats in a pocket in the box and is locked therein. The stripper can be withdrawn laterally from the pocket. The stripper is connected to an adjustable annular collar on the casing of a gearing unit which drives the chain wheel and is detachably secured to the side of the box remote from the frame. The gearing unit and stripper can thus be withdrawn together laterally from the box and the chain wheel can likewise be withdrawn laterally via an aperture in the side of the box remote from the frame.

Abstract: A cable assembly for use in electro-hydraulic control systems of mineral mining installations is composed of a cable with a plurality of electrical wires encased in a multi-layered armoured sheath and connectors at the ends of the cable. The cable is bonded to sealing bodies which fit in the connectors. The connectors are one-piece components each with a sleeve for coupling to the cable and a plug which fits into a socket of a complementary connector. The sealing bodies locate in the sleeves of the connectors and the wires pass through the sealing bodies to join with contacts supported by carriers in the plugs of the connectors. A screw-threaded ring clamps the cable to the sleeve of each connector.

Abstract: The operation of an electromagnetic valve is monitored by connecting the coil of the valve to a d.c. source for a period of time sufficient to permit the current in the coil to reach its maximum steady state value then disconnecting the coil to permit the current to fall and re-connecting the coil to the source again and measuring the current which is established in the coil.

Abstract: A roof support employs an hydraulic piston and cylinder unit as an adjustment device between the goaf shield and the roof-engaging structure. The cylinder unit is mounted to the shield with the aid of a bearing body defining a cup receiving a spherical end of the cylinder. The body also has recesses accessible via offset openings in which journals projecting from the cylinder are located. Locking pieces detachably fitted to the shield block the openings to retain the journals therein yet permit easy assembly and dismantling of the unit.

Abstract: A reactive-track type propulsion system for a mineral winning machine comprises a sprocket chain located along the path of intended movement and a sprocket wheel with teeth meshing with the chain. The wheel is mounted on the machine and driven to propel the machine along the chain. The chain has horizontal oval links and vertical links which have planar end faces which make driving and rolling contact with the flanks of the teeth of the sprocket wheel.

Abstract: To increase the height of operation of a shield type roof support an attachment is fitted to the floor sill or to each of a pair of spaced-apart floor skids. The attachment has side walls with bores for receiving pivot pins used to link the attachment to the floor sill or skid and to guide levers connected to the goaf shield. A transverse body extends between the side walls and defines a socket for forming part of a ball-and-socket joint connecting the attachment to a hydraulic prop. The side walls of the attachment have under surfaces which rest on a support surface of the skid or sill near the working face.

Abstract: Pipe-driving apparatus used to create a pipe line of small diameter uses a pressing station in an access trench to drive in pipe sections one by one. A boring head and conveyor worm operates at the front of the pipe line in a working pipe section on which a cutting shoe is swivably mounted. The worm is a spiral flight on a drive shaft which runs within an open fronted container on which a drive unit for the boring head and the worm is mounted. Hydraulic bracing units mounted to the container can be swung out and engaged with stops in the working pipe section to brace the container during the filling operation. Projections on the container engage with the shoe and the bracing units can be used to steer the shoe. When the container is filled the bracing units re stowed and the container is withdrawn back down the pipe line to the access trench for discharging the material.

Abstract: A pressure-relief valve device has the stem of a valve member guided within a sealed bore of a guide piece screwed into or onto a sleeve-like housing. A spring in the housing acts on a pressure disk to create closure force on the head of the valve member. A connector, which may provide a plug-in connection to some equipment to be controlled, is in screw-threaded engagement with the guide and can be removed to provide ready access to the valve member without disturbing the remainder of the assembly and its setting. The valve member has a piston opposite the head which fits in a recess in the connector. An end wall of the recess forms a stop limiting the closed position of the valve and an end face of the guide forms a complementing stop face limiting the open position of the valve.

Abstract: To firmly connect an upper trough-like component of a scraper-chain conveyor to a lower component use is made of arch-like locking pieces which fit on a side plate of the lower component which overlaps the side wall of the upper component. The upper regions of the locking pieces having inwardly projecting noses which fit into apertures in the side plate and side wall. Sockets are formed in projections on the side plate to receive the heads of screw-threaded securing elements which locate in recesses in the locking pieces and project through holes in side walls thereof. The securing elements adopt an inclined disposition and when nuts are tightened on their shanks the locking pieces tend to force and hold the upper component down on the lower component.

Abstract: A cutter-bit assembly employs an arcuate wedge to secure a cutter-bit within a pocket of a holder. The wedge fits into a tapered gap between complementary curved surfaces of the holder and the cutter-bit shank. A projecting insert carried by the shank mates with a serrated portion on the wedge. Contact is established between the wedge and the curved surfaces of the holder and the shank over outer regions separated by non-contacting clearances.

Abstract: A mine roof support has a slidable extension at the front end of an auxiliary roof cap pivoted for swinging up and down on a main cap. To prevent the extension from being extended when the angle of inclination of the auxiliary cap is too high an insulative cylindrical block is fitted to say the auxiliary cap to partially rotate as the auxiliary cap pivots. A flattened region on the block supports a metallic plate and indexes as the auxiliary cap pivots. A resiliently-mounted proximity switch on the main cap senses the presence of the plate and produces a signal to prevent the extension from being extended.

Abstract: The invention relates to a distributor for controlling hydraulic distribution between hydraulic consumers of a mine roof support unit and hydraulic supply lines extending along a mine working. The distributor comprises a supply block provided with a plurality of pairs of main hose connections and a plurality of branch hose connections. The hose connections of each pair of main hose connections are connected by a respective main passage. Each branch hose connector is connected to a corresponding main passage by a respective branch passage. The supply block is provided with two sets of shut-off valves, the shut-off valves of one valve set being arranged in the main passages, and the shut-off valves of the other valve set being arranged in the branch passages. The hose connections of each pair of main hose connections are connected into a respective hydraulic supply line, and the branch hose connections are connected to the hydraulic consumers of the roof support unit.

Abstract: A scraper-chain conveyor channel section comprises a return trough and a conveyor trough. The return trough is constituted by a pair of side walls interconnected by a floor plate. A respective support bar is fixed to each of the side walls of the return trough. The support bars have portions extending upwardly beyond the side walls of the return trough. The conveyor trough is arranged between the upwardly-extending portions of the support bars. The conveyor trough is constituted by a pair of side walls interconnected by a floor plate. Respective connection means are provided for connecting the conveyor trough to each of the support bars. Each of the connection means includes a plurality of bolts and a plurality of clamping members. Each of the bolts is seated in a respective pocket in the associated support bar, and is engageable with a respective clamping member to force that clamping member into engagement with a respective clamping face on the conveyor trough.

Abstract: The pans of a scraper-chain conveyor are interconnected by way of a dog-bone type connector with enlarged end regions and a central shank which fits into shaped compartments in the side walls of adjacent pans. A hook-like projection on one of the end regions engages in a recess adjoining one of the pockets and a complementary web-like projection on the other end region lies in an opening adjoining the other of the pockets. A swivelling locking plate is fitted to the side wall to overlap the web-like projection and retain the connector in place.

Abstract: A transfer station is disclosed for transferring mineral material from a longwall conveyor to a loading conveyor. The loading conveyor has two straight portions joined by a curved portion, one of the straight portions extending in the longitudinal direction of the longwall conveyor, and being positioned beneath the end of the longwall conveyor. The longwall conveyor extends over the loading conveyor in the region of its curved portion. Larger pieces of mineral material are deflected, by a lateral deflector in the exit region of the curved portion of the loading conveyor, from the longwall conveyor, while the finer conveyed material is delivered at the end of the longwall conveyor onto the loading conveyor.

Abstract: A cutting head for a selective cutting machine includes internally-fed spraying means including a high pressure water control means which is designed in such a way that only spray nozzles adjacent to cutting tools that are actually cutting are supplied with water under pressure. The water under pressure is supplied from a boom to the rotating cutting head via a piston whose free end surface is pressed, by the pressurized water, against a control surface provided on the cutting head. Said free end surface is formed with a control opening which overlaps control ducts provided in the control surface during rotation of the cutting head, thereby controlling the flow of pressurized water to the various groups of spray nozzles. Non-return valves, which keep the control ducts closed, when they are not aligned with the control opening of the piston, are located in the control ducts.

Abstract: A cross-axis cutting assembly of a selective cutting machine is provided with internally-fed spray means. The assembly includes two cutting heads supported by a boom, the cutting heads being driven by a shaft which is transverse to the boom. A high pressure water supply line for each cutting head is provided by means of a connecting member. Each connecting member is arranged externally on the boom, is preferably designed as a channelled plate, and closely fits the external contour of the associated cutting head. Each connecting member extends to the free end of the shaft, and is connected to an internal high pressure water duct formed in the associated cutting head by means of a rotary arrangement. Each rotary arrangement has an axial pin which fits sealingly into a passage.

Abstract: A distributor block for interconnecting a hose bundle to a control device of a pressure fluid control system in an underground mine working has internal passageways for connecting valves of the device to individual hoses. Bores in the block receive detachable elongate coupling members which themselves have internal bores and plugs for engaging in sockets within the control device. The coupling members are journalled in the block for slight transverse and angular movements within seals.