Abstract: A control for a mining machine having means for traversing a ground surface and a universally-pivotal carrier arm of variable length which carries at its forward end a cutter drum. A displacement pickup is responsive to forward or aft movement of the cutter drum with respect to the ground surface. Means are connected to the displacement pickup for producing a first signal when said cutter drum has moved forwardly in an amount substantially equal to its length and for thereafter producing a second signal when the cutter drum is moved backwardly in an amount equal to a fraction of its length. These signals are used to control forward or aft movement of the mining machine over the ground surface, or extension or retraction of the variable length carrier arm, to remove ribs in the side walls after a cut has been taken from the mine face area, these ribs resulting from the shape of the cutter drum and its angularity with respect to the mine roadway side walls.

Abstract: A high-pressure ball valve includes a valve housing with a bore that sealingly receives a cylindrical extension of a valve member. An inlet bore extending to the bore in the valve housing has a bottom seat against which a ball can seal off the inlet bore. The cylindrical extension has a pocket to receive the ball while engaging a stem that extends through a bore in the valve member against a piston of a single-acting piston and cylinder assembly. An outlet bore extends in the valve housing to the bore therein for delivering the fluid passing into the housing from the outlet bore.

Abstract: A device for interconnecting two sections of a longwall mining machine secured to the side wall of a face conveyor, characterized in that lugs project outwardly from the sides of adjacent end portions of the respective track sections and receive an oval chain link securing element which extends around the lugs and bridges the joint between the respective track sections.The chain link element has horizontally-extending portions interconnecting semicircular end portions which extend around the lugs, the horizontally-extending portions being such that elongation of the interconnecting device is limited as is the separation between adjacent end portions. This insures that the clearance between ends of adjacent track sections is sufficient to provide for the correct tooth spacing on a drive rack to accommodate the driving wheel of a mining machine.

Abstract: An electrical power supply and liquid supply arrangement for a mining machine, particularly a longwall mining machine, wherein extended lengths of a power supply cable and liquid supply conduit are disposed within a housing structure extending along one side of the course of travel of the mining machine. A side arm on the mining machine extends through a slot in a face plate of the housing structure and carries at its outer end a junction box within which power cables leading from the mining machine can be connected to or disconnected from an external power cable. Clamped to the aforesaid junction box is the liquid supply conduit which can be selectively coupled to, or uncoupled from, a mating supply conduit leading to the interior of the mining machine. The arrangement permits connection or disconnection of the power supply and water supply members to or from the mining machine without any disassembly of the machine itself.

Abstract: A longwall mining machine and method for its use, the machine traveling over a face conveyor having a first toothed rack extending therealong. A gantry-like frame is movable along the face conveyor and has upstanding supports at its opposite ends which carry an upper track and a second toothed rack. A first mining machine frame is carried on the face conveyor and has drive pinion means engageable with the first toothed rack. A second mining machine frame is carried on the upper track of the gantry-like frame and has drive pinion means engageable with the second toothed rack. The first and second mining machine frames each having a shearer drum mounted thereon for cutting and removing a mineral seam.

Abstract: A cutter drum assembly for longwall mining machines incorporating means for spraying trickle water onto the face area being mined as the cutter drum rotates. This requires valving for supplying high-pressure liquid to only those nozzles adjacent the face area as the drum rotates. In accordance with the invention, the valving takes the form of individual valves spaced around the drum, the valves being actuated by a relatively low-pressure control medium (i.e., a liquid) which obviates the necessity for the close tolerances and rigid sealing requirements of prior art devices where high-pressure liquid valve assemblies were built into the rotary connection between a support shaft and the drum which rotates about it.

Abstract: A cutter drum for longwall mining machines and the like of the type comprising a rotatable member having cutting bits disposed on its outer periphery and arranged to rotate about an axis extending parallel to a mine floor, the drum being movable along a longitudinal face to produce a cut extending back into the face as the drum rotates and advances. Nozzles are carried on the end of the drum at the back of the cut for spraying high-pressure liquid into the material being mined to loosen and dislodge the same. This has the advantage of eliminating cutter picks at the back of the cut and materially reduces the generation of fines and dust in this area.

Abstract: A fluid coupling for interconnecting a liquid-conveying duct in a shaft element to a duct in a hub element, the two elements being rotatable relative to each other. The shaft element has a central passageway subjected to fluid under high pressure and has an enlarged-diameter end communicating with a smaller-diameter portion. The end of the large diameter portion of the shaft element remote from its small diameter portion is subjected to fluid under high pressure in said passageway; while the opposite end of the large diameter shaft portion is subjected to a sealing fluid. The pressure of the sealing fluid is always greater than that of the high-pressure fluid, with the result that the high-pressure fluid will not enter the chamber filled with sealing fluid to decompose it and form an emulsion.

Abstract: A track and gear rack disposed on one side of a face conveyor for a longwall mining machine and adapted to be engaged by a driving gear and guide wheels on the mining machine, the track and gear rack being of generally L-shaped cross-sectional configuration and having a horizontal arm resting on the mine floor and a vertical arm secured to the face wall of the conveyor. Driving pin extensions extend outwardly from the vertical arm in cantilever beam relationship near the upper edge of the vertical arm and have vertical widths less than the height of the vertical arm. One of the arms of the L-shaped configuration is provided with studs which engage guide block means on the mining machine for guiding it along the track and gear rack. The invention facilitates good guidance of the mining machine along the track and gear rack without impeding the flow of mined material onto the face conveyor.

Abstract: A coal-mining machine is advanced along a face conveyor by providing a rack extending along the conveyor and a plurality of advancing units. Each advancing unit includes a hydraulic motor to rotate a drive wheel while meshing with the teeth of the gear rack. The advancing units arranged side-by-side along the mining machine have curved end faces to abut against one another. Runners are provided on the advancing units at the opposite ends of the mining machine which extend partially around the rack for guiding and maintaining the drive wheel engaged with the teeth of the rack.

Abstract: A rotary fluid coupling for conveying fluid from a stationary shaft to a hub rotatably mounted on the shaft, or vice versa. The coupling is characterized in having a shaft provided with an axial passageway extending therethrough, one end of the passageway being connected to a source of high pressure fluid and the other being connected to a source of high-viscosity sealing fluid (e.g., a lubricant). A piston in the passageway separates the high-viscosity sealing fluid from the high pressure fluid, the latter being conveyed to the surrounding hub through radial passageways formed in an enlarged diameter portion of the shaft. The high-viscosity sealing fluid is applied to both ends of the enlarged diameter portion of the shaft to form a seal which prevents escape of the high pressure fluid.

Abstract: A cutter bit assembly for a mining machine cutter head incorporating a novel valve in the form of a resilient sleeve which is deflected to open the valve and conduct fluid through nozzle means at the tip of the bit when the bit is forced into a bore as it engages material being mined.

Abstract: Rack segments are formed with teeth to mesh with drive gears of a mining machine to propel it along a conveyor. The drive gears are spaced apart and mounted on a drive shaft with a sleeve member therebetween to engage the top surface of a rack segment. The rack segment has a rectangular body with arch-shaped upper and lower surfaces. Opposite end portions have a vertical hole to receive a support member which is anchored in place by a pin passed through an opening transversely thereto and arranged along a horizontal plane of symmetry. Attachments forming gear teeth project at uniformly-spaced intervals from opposite lateral sides of the rack body. The attachments have involute-like flanks extending upwardly and downwardly from the horizontal plane of symmetry such that a worn rack segment can be continually used by inverting its position 180.degree..

Abstract: A rotary fluid coupling for conveying fluid from a stationary shaft to a hub rotatably mounted on the shaft, or vice versa. The coupling is characterized in having an annular piston which surrounds the shaft and which forms a wall of a chamber connecting a duct in the shaft to a duct in the wall of the hub. A seal is disposed around the shaft between the piston and a closed end of a bore in the hub. In the bore between the piston and the seal is a lubricating material such that pressure exerted on the piston by fluid in the aforesaid chamber will be transmitted by the lubricating material to the seal, preferably a labyrinth seal.

Abstract: In cutter-drum apparatus wherein a cutter drum is provided near the back of the cut with a nozzle holder and nozzles for comminuting without dust evolution of the harder material at the back of the cut, improvements whereby (a) the nozzle holder is frusto-conical to accommodate the bulging of the face at the back of the cut, and (b) the cutter drum has a frusto-conical end ring which bears cutter picks that intersect the jets emerging from the nozzles. These cutter picks give the jets a pulsating action, which increases their effectiveness.

Abstract: A conveyor trough for a scraper conveyor is used as a way or track for an underground mining machine. The conveyor trough includes a trough base with lateral section members welded thereto along the longitudinal sides and form at each side a V-shaped space that extends from the plane of the trough base to the height of the section member. A lateral section member descends toward the floor at each side of the trough base where it extends to a flange parallel to the mine floor and projects from the lateral section from the lateral section member. The flange has a width and thickness to form a machineway or track. Divering arms at each side of the trough base extend to a flange which projects from the arm to extend parallel to the floor and forms a machineway or track by the width and thickness dimensions thereof.

Abstract: A cutter drum assembly for a longwall mining machine of the type having a cowl pivotal about the axis of the drum and nozzles on the periphery of its spiral conveying flights for directing a trickle of liquid onto the face area being mined. The cowl, which is normally on the side of the drum opposite the face being mined, carries a cam which controls valves supplying liquid to the nozzles such that at any time water is delivered only from those nozzles adjacent the working face area.

Abstract: A support arm for a cutter drum carried on a longwall mining machine characterized in being formed from two telescoping parts, at least one of which is movable axially relative to the other to change the length of the arm. This enables the mining machine to cut material from a coal seam with one support arm length and roadways at opposite ends of the seam face with longer support arm lengths without the necessity for raising the mining machine on its support tracks in the roadway areas or otherwise adjusting the vertical heights of the support arms.

Abstract: A hollow gearwheel has internal teeth that mesh directly or through an intermediate gear with the teeth of a drive gear of a machine drive on a drum cutter mining machine. External teeth on the hollow gearwheel mesh with the teeth of a rack extending over the distance traversed by the mining machine along the face of a longwall mine. A plate pivots about the rotational axis of the drive gear while the plate forms a closure to the side of the hollow gearwheel facing the mining machine. The plate carries a bearing support for the arbor shaft of the hollow gearwheel and forms a seal along the outer peripheral edge of the hollow gearwheel. A carrier includes a bearing to support the outer end of the arbor shaft. The carrier is moved along a recess in a housing for the hollow gearwheel to adjust, by pivotal positioning, the hollow gearwheel.

Abstract: Mining equipment of the type operably dependent on the voltage and/or the phase of electric current is isolated from electric supply mains by an OFF switch in a control circuit before a current supply relay drops out. The OFF switch and an ON switch are coupled in a monitoring conductor which supplies current to a photo-electronic coupler. An output signal from the coupler is delivered to a battery fed integrator to provide a control signal to an output relay for a switch in the current supply line on mining equipment. The ON switch is bridged by a normally closed switch coupled to a relay which is responsive to operating current fed to the machine. In a second embodiment, thermal sensing elements for motor windings on the machine provide a signal to battery fed relays to open a normally closed switch in a circuit bridging the photo-electronic coupler.