Abstract: The telescopically extendable prop (1) has at the periphery of the intermediate prop (3) abutments (30) which cooperate with a valve (15) before the intermediate prop (3) has attained its highest extended position. The valve (15) stops the extending stroke of the intermediate prop (3) and is releasing the beginning of the extending stroke of the top prop (4). As soon as a predetermined pressure is built up in the consolidating conduit (10) of the top prop (4), the valve (27) subjected to this pressure is overacting the valve (15) cooperating with the abutments (30) of the intermediate prop (3), whereupon the consolidating stroke is completed by pressurizing the intermediate prop (3) with pressurizing fluid. (FIG.

Abstract: The device for provisionally supporting a gallery or a tunnel which definitely shall be supported by support frames closed on all sides comprises a floor girder which servs as a part of the provisional frame as well as of the definite one. For the provisional support said floor girders are laid out separately near the mining face. Only U-shaped elements which are reduceable in profile are to be brought forward through the inner width of the positioned frames. These U-shaped elements may be connected with the said floor girders to form a complete provisional supporting frame closed on all sides. Such provisional support fulfills absolutely the safety requirements, and setting the definite frames may be carried out quickly and without long lasting interruptions of biasing the roof because the provisional floor girders remain usable as floor girders for the definite supporting frames, too.

Abstract: The mine roof supporting structure comprises hydraulic props (3) which are pressing a swivelling cap (8) against the mine roof. A link lever (5) is pivotally linked to the floor frame (1) and a shield (4) is pivotally linked to the link lever (5) and to the cap (8). The shield (4) is pulled in direction to the floor frame (1) by means of a hydraulic tension strut (14). The working chamber (24) of the tension strut (16), which working chamber includes the piston rod and is facing the pivotal point (12) of the tension strut (16) to the shield (4), can be brought in connection with the supply conduit (19) for feeding pressurized fluid to the props (3) via a spring loaded check valve (22, 23), noting that the opening pressure of the spring (22) is smaller than the final supporting pressure exerted by the props (3). The piston surface of the working chamber (24) is smaller than the piston surface (4) delimiting the working chamber of the props (3).

Abstract: The cutting head (6) is a hollow cutting head and rotatably supported on a carrier (11). Water is supplied to the nozzles of the cutting head (6) via a supply tube (29) rigidly connected to the carrier (11) in the axis of rotation and opening into a distribution chamber (30) within the cutting head (6). From this distribution chamber (30) the water is fed via passages into annular gaps (43, 46) extending in axial direction. Passages (47, 48) are opening into these annular gaps (43, 46) for supplying the water to the nozzles. A sealing (31) is only required where the water supply tube (29) is opening into the distributing chamber (30).

Abstract: An assembly for cooling the teeth of the cutting heads of a mining machine and, at the same time, the rock face. The cutting heads are rotatably supported and, at the same time, the rock face, the axis of rotation being essentially horizontal. Cooling is performed by water jets distributed by spray nozzles.In order to obtain a sufficient cooling effect for the cutting teeth and the rock face with a water consumption as low as possible, there are provided on the jib arm two groups of spray nozzles for each cutting head. The nozzles of the first group are directed to the region of the teeth in the highest position of the same while the nozzles of the second are directed into the interspaces between the rows of teeth in the said region.The flow of water can be shut off separately for each group of nozzles associated with each of the cutting heads.

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: The rotary-shaft bit (7) inserted in a bushing (3) fixedly mounted, encloses by means of a hollow-cylindrical extension (9) an annular extension (5) of the bushing (3) and projecting in axial direction of said bushing (3), and in this manner is supported closer to the tip of the bit (8) in order to absorb transverse forces, noting that the front surface (14) of the hollow-cylindrical extension (9) of the bit (7) can be supported on the flange (4) of the bushing (3) (FIG. 1).

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: 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: 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: A cutting bit includes a bit tip and a shaft having a portion tapered toward the tip and having a reduced diameter between the tapered portion and the portion intended to be inserted in a holder. The bit tip has the shape of a body of revolution with convex generatrices.

Abstract: A grease gun comprising a hollow piston rod driven by a pressure fluid upon an annular drive piston at one end of the rod, compressing a supply of grease by an annular plunger at the other end of the rod into a receiving chamber within the piston rod, which chamber cooperates with a stationary surface, upon reversely driving the piston rod, to expel the grease through a conduit from the chamber at a higher pressure than the driving fluid.

Abstract: A pressure relief valve for hydraulic mine supporting elements, particularly mine props, has a valve member loaded in its closing direction by a spring, a piston is connected to the valve member end sealingly sliding within a cylinder of the valve housing and arranged to be acted upon in closing direction by the pressure prevailing within the space before the seat of the valve member. The valve member has a neck portion of reduced diameter between the valve seat and the piston and the annular cross section, being acted upon in closing direction, between the neck portion and the circumference of the piston is smaller than the annular cross section, being acted upon in opening direction, between the neck portion and the valve seat.

Abstract: In a method and apparatus for cutting minerals utilizing a cutting tool provided with cutting teeth, the tool rotates about an axis approximately parallel to the winning face and is moved at a feeding rate essentially in axial direction. Several grooves spaced from each other are carved in sequence, and in dependence on the mineral properties the feeding rate is increased with respect to the rotatory velocity when a brittle mineral is to be cut, while the feeding rate is diminished with a tough mineral.

Abstract: A cutting machine has at each side of a universally pivotable cutter boom a cutting head which is rotatably supported around an axis extending vertically to the longitudinal direction of the cutter boom and which is advanced in direction of its axis when the cutter boom is pivoted. The cutting heads are propelled by a drive unit via a reduction gearing arranged within the cutter boom, the last stage of the reduction gearing being arranged within cutting heads which are hollow.

Abstract: Apparatus for guying a movable cutting machine equipped with a caterpillar drive and for moving the machine on ascending galleries has at both sides of the cutting machine tension members formed of chains or ropes and led over winches. The tension members are adapted to be fixed on both sides of the cutting machine, with the forward ends and the rearward ends of the tension members being adapted to be fixed at stationary locations of the gallery, preferably by means of rock anchors.

Abstract: Device for consecutively supporting a drift by means of caps and posts or props in dependence on face advancement, said device being designed for lifting and for pressing the caps to be positioned against the mine roof, characterized in that a breast frame is provided for being suspended to the positioned caps in a manner to be shiftable in direction of face advancement, lifting beams forming a support for the caps to be positioned being supported on said breast frame for being lifted in upward direction and a crane being guided on the breast frame for being shifted in direction of face advancement.

Abstract: The invention relates to a shield structure particularly adapted for longwall mining providing a protected area that effectively insures operator safety even if total collapse of the mine roof should occur. The prop supporting the load-bearing cap of the shield is inclined rearwardly with respect to the mine face, and a pair of tension links that are pivotally connected to each other and are acted upon by a hydraulic cylinder in a direction transverse to the tension links, provide a structure which will ensure a widened (though shorter) protected area in which an operator may reside even upon complete roof collapse. The widening of the area helps insure that any fallen material from the roof will not harm an operator in the protected area.

Abstract: Crawler track means are mounted on and adapted to carry the frame of the machine and have a tread having a rear end. A loader is mounted on and protrudes forwardly beyond the forward end of said frame and has a scooping lip which has the configuration of an arrowhead and is formed with forward edges defining a plane. The loader is forwardly and downwardly inclined toward the scooping lip and is adapted to be raised and lowered relative to the frame and crawler track means and adapted to assume a lowermost position. When the loader is in said lowermost position, said plane defined by said forward edges of said scooping lip is tangent to said crawler track means behind the center of the length of said crawler track means and spaced from said tread before the center of the length of said crawler track means.