Abstract: A hydraulic mine prop includes an inner piston-like prop guided within an outer cylinder-like prop, and a roof fall valve. The interior space of said inner prop communicates freely with the working chamber of the prop, and the roof fall valve is arranged outwardly on the prop and rigidly secured thereon, the valve being connected to the working chamber by an orifice provided in the prop and leading to the working chamber. The cross-sectional area of the roof fall valve in its open position.

Abstract: A method of controlling the working motion of a cutting tool of a tunnel-driving machine over the breast, wherein the actual position of the cutting tool is ascertained in consideration of the position of the tunnel-driving machine relative to the desired section of the tunnel, characterized in that at least one point of reference, which is fixed in space, is aligned relative to the longitudinal axis of the tunnel, e.g., be means of a laser beam, the times of travel of signals between at least one such point of reference and two points of the tunnel-driving machine or between at least two such points of reference and at least one point of the tunnel-driving machine are measured, the measured times of travel are subsequently utilized in a trigonometric computation of the actual position of the tunnel-driving machine, and the cutting tool is adjusted to its desired position by reference to the actual position of the cutting machine.

Abstract: A cutting machine includes an endless conveyor and a loading ramp having movable loading arms which continuously shift the cut material in an upward direction of the loading ramp to conveyor. The rear deflector wheel of the conveyor is driven by a squirrel-cage motor, and the drive of the loading arms is, via the conveyor derived from the front deflector wheel. A slipper clutch is interpositioned within the drive between the motor and the loading arms, and the slide torque of the slipper clutch as reduced to the motor shaft, exceeds the breakdown torque of the squirrel-cage motor.

Abstract: A device for preventing penetration of dust from the outside inwardly into an annular gap between a cutter arm of a cutting machine and a rotatable cutting head carried on said arm, said cutting head having an interior space containing lubricating oil, said device comprising a first seal closing off said interior space and located in said gap, a second seal located in said gap outwardly of said first seal, the grease flow resistance of said second seal in the outward direction being less than the grease flow resistance of said first seal in an inward direction, and a pressurized grease supply line arranged within said cutter arm opening into said gap at a location between said first and second seals whereby during operation of the cutting head grease flows outwardly through said gap and prevents entry of dust into said gap.

Abstract: It is an object of the invention to provide an improved shield-carrying roof support unit which has a linkage for adjusting the elevation of the cap while the pivotal connection between the cap and the shield is constrained to move substantially at right angles to the base frame. The provision of auxiliary links having pivotal connections at properly selected points results in a linkage which has a precisely defined configuration and avoids an overloading of the pivotal connections such as could occur in known shield-carrying roof support units of the same kind.

Abstract: Two universal joint shafts for driving a pair of working shafts of a strip-treating stand are arranged one over the other and adapted to be shortened so as to be uncoupled from said working shafts. For a replacement of one or both working shafts, the unversal joint shafts which are uncoupled from the working shafts and are supported by respective seating structures, which are adjustable in height. To enable an automatic coupling of the universal joint shafts to the working shaft and to permit of the use of interchangeable strip-treating stands, which can only be lifted, the seating structures comprise upwardly facing bearing surfaces, which are adapted to support and to clear said universal joint shafts. Said seating structures are mounted in a carrier, which is adjustable in height and carries also means for adjusting said bearing surfaces in height relative to said carrier only by equal distances in opposite directions.

Abstract: A gas scrubber having an air inlet and an air exit, said scrubber comprising: a plurality of venturi tubes having upstream ends and downstream ends, the venturi tubes being arranged parallel to each other; a centrifugal separator in communication with the downstream ends of the venturi tubes; a blower for drawing dust-laden air into the upstream ends of the venturi tubes and then into the centrifugal separator; nozzles for introducing water into the air flowing through the venturi tubes; an inner tubular housing surrounding the venturi tubes; an outer tubular housing surrounding and spaced from the inner tubular housing so as to form a space between the housings; a conduit for conducting air from the blower to the air exit; a funnel widening in the air flow direction so as to have an inlet end and an outlet end of larger cross section than the inlet end, the inlet end being connected to the air exit; and porous air filter material connected completely across the outlet end of the funnel.

Abstract: An annular inner vane cover is axially spaced from a rotatably mounted runner and has first and second flanges. An annular water guide is disposed between said runner and said inner vane cover and has a third flange, which is jointed to said first flange. An inner tubular housing has a fourth flange, which is joined to said second flange. An annular runner cover surrounds said runner and has a fifth flange. An annular outer vane cover surrounds said inner vane cover and is radially spaced therefrom and has a sixth flange joined to said fifth flange, and a seventh flange. An outer tubular housing surrounds the inner tubular housing and is radially spaced therefrom and defines a welded interface with said outer vane cover. Outer and inner vane mounts are carried by said outer and inner vane covers, respectively. A plurality of vanes are provided, each of which is mounted for rotation on its own axis in one of said outer vane mounts and one of said inner vane mounts. Said flanges lie in parallel planes.

Abstract: In a cutting machine having a cutter arm which is mounted at one end for universal pivotal movement and which carries at its free end a cutting tool: a walk-on platform covering at least part of the cutter arm, said platform being box-shaped in cross-section and having a width greater than the width of the cutter arm so as to protrude beyond the sides of the cutter arm and said platform having a generally planar top wall and a bottom wall which conforms to and rests on the exterior surface of the cutter arm; and at least one walk-on plate hinged to the platform at a side edge thereof for swinging movement about an axis which is approximately parallel to the axis of the cutter arm, said plate having a width less than the width of the upper wall of the platform movable from a position in which it lies on the top wall of the platform to an extended position in which it is approximately co-planar with the top wall of the platform.

Abstract: In a rock cutting machine which includes a cutter arm having an inner end and an outer end carrying a toothed cutter which rotates about an axis transverse to the longitudinal dimension of the arm, an improved cooling device for the cutting teeth of the cutter comprising a nozzle device for receiving supplies of compressed air and water and constructed to create and discharge a stream of air in which particles of liquid water are dispersed or atomized, the nozzle device being carried by the cutter arm at a location spaced from the cutter toward the inner end of the arm and arranged in a position to discharge the stream toward the cutter in a spray pattern such that the stream impinges on the teeth of the cutter as the teeth pass through the pattern during rotation of the cutter.

Abstract: In a continuous casting plant the space between the walls of a cooled continuous casting mould and the head of a starter bar is sealed. The seal is achieved by means of an elastic member inserted in an annular peripheral recess of the starter bar head. The elastic member closes the recess, extends completely around the starter bar head in the groove and may have a cylindrical or plane shape.

Abstract: In a method of and apparatus for continuously casting a steel strand with a mould having a closed bottom molten steel is cast from a casting container into the mould, and the mould is moved away in a substantially horizontal direction to form a strand with a solidified skin and a liquid core, which strand is longer than the mould. Then the strand outside the mould is supplied with heat to maintain a uniform temperature of the liquid core, which temperature is higher than the liquidus temperature of the steel over most of the longitudinal extension of the strand.

Abstract: Chemically resistant steels for containers are butt welded by using an automatic welding process. The electrode is oscillated over the whole width of the seam and is kept to a maximum thickness of 1 mm.

Abstract: A mould arrangement for continuous casting plants has a mould with side walls adjustable to various strand sizes, supporting devices below the mould for guiding the emerging strand, and holding devices releasable from above for securing the supporting devices to the mould. The supporting devices are arranged in hollow spaces extending through the mould side walls to the upper side thereof.

Abstract: A container arrangement for treating lumpy and grained materials in a packed bed with gaseous media has at least one container with an opening and a device for closing the opening. In the at least one container at least two chambers are formed whose bottom portions communicate with each other. A supply conduit is connected to the top portion of one of the at least two chambers and a drain conduit is connected to the top portion of the respective other one of the at least two chambers so as to form a forced guidance for the gaseous media through the packed bed.

Abstract: A method of joining frogs consisting of wear-resisting austenitic manganese steel casting to rails of carbon steel by welding and with the aid of an interposed connector consisting of austenitic low-carbon steel, characterized in that the connector is first welded to the regular rail or interconnecting rail, particularly by flash-butt welding, that the length of the connector which has been welded to the regular rail is limited to 20 to 25 mm, at most, preferably to 15 to 20 mm, that in a second welding operation the frog consisting of a wear-resisting manganese steel casting is welded to the connector, preferably by flash-butt welding, and that the cooling after the second welding operation is effected at a higher rate than the cooling after the first welding operation.

Abstract: In a base anchorage for heavy machinery, in particular converters, an anchoring plate is concreted into a base and is firmly connected with at least one bolt, whose end projecting out of the base is provided with a screw thread. The at least one bolt is produced of high-tensile strength material and, at its lower end, it is screwed through a threaded bore in the anchoring plate and contacts, with at least one flattened side, a corresponding face of a securing plate fixed relative to the anchoring plate, the bolt thus being secured against rotation.

Abstract: A rail switch in which two wing rails are engageable with a frog in alternation, characterized in that guide members are provided, which are held in position relative to the wing rails and extend under and are engageable with the frog or parts rigidly connected to the frog to prevent an upward movement of said guide members.

Abstract: An arrangement for tensioning a gateway conveyor in a sloping gateway during longwall working using supports having base frames which are provided with pulling and shifting hydraulic actuators, wherein in a tensioning device is provided at least at one of the supports and is connected at one end to the gateway conveyor and at the other end to a slide member which is slidably guided by the base frame of the support for a movement which is transverse to the longitudinal direction of the gateway conveyor, characterized in that the slide member which is slidably guided for a movement which is transverse to the longitudinal direction of the gateway conveyor consists of a guide frame, which is supported by the base frame against forces acting in the longitudinal direction of the gateway conveyor, the cylinder of the pulling and shifting actuator is axially immovably mounted in the base frame and its piston is connected to said guide frame, which when retracted extends on opposite sides of the pulling and shifting a

Abstract: A strand guiding roller to be used for a continuously cast strand includes a plurality of roller bodies designed as exchangeable wear sleeves and arranged on a drivable shaft at a distance from each other, a plurality of bearings distributedly arranged over the length of the roller to rotatably accommodate the drivable shaft therein, and catch connections provided between the exchangeable wear sleeves and the drivable shaft to secure the exchangeable wear sleeves against rotation.