Low Profile Coal Mining Apparatus

Abstract

Apparatus for mining shallow seams of coal or the like employs a combination of parts resulting in a low profile of the machine and which may be operated without requiring an operator to accompany the machine to the mine face. The mining augers are remotely controlled and may be adjusted to provide for mining of seams which are thicker than the minimum profile height of the machine. The augers are mounted on a carriage which travels along guides on a base plate which can be shifted toward or from the mine face by remote control, and the superstructure mounted on the carriage reaches a height no greater than the diameter of the augers.

Description

BACKGROUND OF THE INVENTION

The present practice of auger mining of coal which does not require an operator to crawl into the mine has obvious safety value, but has other disadvantages such as the cummulative demand for power as the auger length is extended, the periodic down-time as the auger length is modified, and the amount of labor involved. Other types of mining apparatus in which robot machines are employed, such for example as the machines disclosed in the Alspaugh, et al., U.S. Pat. Nos. 2,699,328 and 2,826,402, are relatively expensive and complex, and in addition require considerable attention for maintenance. Moreover, machines of this type are not well suited for low seams, as illustrated by the definition in Alspaugh U.S. Pat. No. 2,699,328 wherein the compact machine is stated to be 3 feet high.

As will be understood, mining of the so-called `low seams` of coal or other materials has long presented problems to the designers of mining machines and to operators of the same. Obviously, the thinner the seam being mined the more cramped will be the space in which an operator can accompany the apparatus during the mining operation Accordingly, the need for remote control of the machine increases with the dimunition of seam thickness while at the same time the lower the profile of the apparatus the more limited is the space available to the designer for the purpose of incorporating the necessary machine elements and controls.

While the term `low seam` is comparative it will be understood that a difference of not more than 1 inch of seam thickness may make all of the difference between a given machine being usable or unusable. Prior art patents often speak of machines for mining `low seams` although a specified dimension may be lacking in their disclosures. As will later appear in the present disclosure, however, the term `low seam` is intended to signify a dimension of not more than 20 inches of seam thickness and indeed may be somewhat less.

This useful feature of the present invention derives essentially from a novel combination of machine elements in which the conveying apparatus, boring apparatus, power drives, and control apparatus are all coordinated to obtain a low profile of the machine by the cumulative effect of lowering the position of such elements to the maximum practical extent. In addition, a conventional walking type of machine is employed which may be operated as a robot from a remote control point.

SUMMARY

The invention is embodied in a low profile dual-auger type of mining apparatus having a base plate with transverse guides along which a carriage is selectively moved. A low profile orbital conveyor is driven by a motor supported on the base plate and passes beneath the carriage. The carriage supports the augers in a selectively pivoted position and includes motors for driving the augers and for pivoting the same to the selected height on the mine face. Remotely controlled means are provided for walking the apparatus toward or from the mine face.

Among the objects of the invention are the provision of an improved remotely controlled mining apparatus for use with low seams; the provision of a low profile mining apparatus which may mine not only low seams, but also seams of greater thickness; the provision of a mining apparatus employing a hydraulic power system controlled by low voltage solenoid valves; the provision of a low profile carriage carrying dual augers and movable transversely of an advancing base plate without requiring the presence of an operator adjacent the base plate; and the provision of an improved conveying means of low profile for removing material dislodged by a pair of augers.

These and other objects and advantages of the invention will become more apparent as the description proceeds and when considered in conjunction with the accompanying drawings in which

FIG. 1 is a diagrammatic view indicating the nature of the cuts which can be made in a seam of coal by the apparatus, the vertical profile of the carriage being shown in dotted lines.

FIG. 2 is a plan view of the base plate and attached skid plate with the carriage removed.

FIG. 3 is a side elevation of the structure of FIG. 2 with elements omitted in the interest of clarity.

FIG. 4 is a plan view of the carriage and augers.

FIG. 5 is a sectional view to a larger scale taken on line 5--5 of FIG. 4 and showing the carriage in operative position on the forward guide.

FIG. 6 is a face view of the carriage supporting means of FIG. 5.

FIG. 7 is a sectional view taken on line 7--7 of FIG. 6.

FIG. 8 is a view of the carriage super structure taken on line 8--8 of FIG. 4 with parts in elevation and with parts omitted in the interest of clarity.

FIG. 9 is a view to a larger scale as taken on line 9--9 of FIG. 4 and showing superstructure of the carriage plate.

FIG. 10 is an elevation view taken on line 10--10 of FIG. 4 and showing superstructure of the carriage plate.

FIG. 11 is a view to a larger scale taken on line 11--11 of FIG. 2 and showing the mounting of the orbital conveyor drive sprocket.

FIG. 12 is a diagrammatic view of the hydraulic drive system, and

FIG. 13 is a wiring diagram for use in the robot control of the apparatus.

A brief outline of the invention may be noted from consideration initially of FIG. 1 indicating the general relationship of the mining apparatus to the mine face 10 and showing its capability of mining not only low seams, but also somewhat larger seams. As will later appear, as the carriage plate 11 is moved along the guide 12, affixed to the base plate 13, from its leftmost position to its rightmost position, a complete cut equal in depth to the diameter of each of the two augers is made, provided, however, that the axes of the two augers are in the same plane. As will be noted, the overall height D of the carriage assembly is somewhat less than the diameter of the augers. When a cut is to be made in a seam thicker than that made in a low seam, the righthand auger after making the entry shown in solid lines at 14 is pivoted upwardly, while rotating, into the dotted position 15, the lefthand auger meanwhile still rotating in the solid line position 16. The carriage is then moved to the right until the righthand auger occupies position 17 and the left hand auger fully overlaps the position 14. While still rotating, the righthand auger is pivoted downwardly into position 18 and the left hand auger is pivoted upwardly into position 19 after which the carriage is moved to its leftmost position with the lefthand auger being pivoted downwardly after it reaches position 20.

With the foregoing in mind, reference now is made to FIGS. 2 and 3 wherein the base plate 13 is shown with the forward guide 12 and rearward guide 21 affixed thereto on its upper surface and spaced from each other, the guide 21 being shorter and providing space for an orbital conveyor to pass around its ends. The conveyor is normally driven in the direction of the arrows and includes spaced shallow flights 22 attached to an endless chain 23 engaged by idler sprockets 25, 26, 27, 28 and 29 and by drive sprocket 24. Outer walls 30, 31, 42 and 32 with arcuate walls 33 and 34 joining walls 30 and 31 respectively with the rear face portion 35 (FIG. 5) of the forward guide 12 and with an arcuate wall 36 joining wall 32 with wall 42 provide a boundary along which the distal ends of the flights will be moved and which confine the material being moved by the conveyor.

As indicated in FIG. 11, the conveyor in its travel from adjacent idler sprocket 26 to adjacent idler sprocket 25 moves in contact with the base plate 13. However, its rearmost travel is along an elevated and canted shelf 40 supported above that base plate and joined at the left end to an intermediate inclined floor plate 41 having a wall 42 which joins walls 32 and 31. At the right end, however, a shorter inclined floor plate 43 extends upwardly from base plate 13 and an elevated opening 143 is provided between this shorter plate and the canted shelf 40. Thus as the orbital conveyor is moved it discharges its contents through that opening onto an elongated bridge conveyor 46, later to be described.

Referring now to FIGS. 4 to 7, the generally rectangular flat carriage plate 11 is provided at both its forward and rearward edges with overhanging brackets 50, 51 respectively within which are journalled the shafts of horizontally rotatable rollers 52 adapted to engage with the outwardly extending faces of the guides, as seen in FIG. 5. A skirt 53 depending from the overhanging bracket and spaced rearwardly of the beveled front edge 54 of the base plate serves to mount the shafts of vertically rotating rollers 55 which engage with the upper surface of the base plate. These rollers support the weight of the carriage and the augers carried thereby. Each end of skirt 53 is curved inwardly to terminate adjacent the rear wall 35 of the guide thereby to shovel the coal out of the path of the roller 55 as the carriage is traversed to produce the mining action indicated in FIG. 1.

As will later be evident, as the augers move the broken coal (which normally is of egg size or smaller) toward the carriage, such coal spills over the top of forward guide 12 into the orbital conveyor which is then moving under the carriage and behind guide 12. Bracket 50 meanwhile is serving to divert the two streams of the coal away from the rollers which mount the carriage on the base plate. Significantly the described carriage mounting construction enables the carriage plate 11 (which is required to carry certain superstructure) to be located at the lowest practicable elevation thus contributing to the low profile of the carriage and to the mining of low seams.

A further important feature is noted on FIG. 8 wherein the carriage plate 11 is provided with an aperture 60 into which the lower portion 61 of the casing of the gear box of the auger driving motor 62 is mounted. This motor comprises a conventional rotary fluid motor with gears serving to drive a shaft 63 having sprockets 64, 65 at its ends. In view of the power required for the auger drive the gear box casing is of appreciable height and, unless lowered as shown, would add to the profile of the mounted carriage. However, sinking of the casing 61 to near the base plate 13 is made possible since space is available between the rear guide 21 and the path of travel of conveyor chain 23. Also shown on FIG. 8 is a portion of the carriage superstructure including a pair of uprights 66, 67 affixed to the upper front surface of plate 11 and spaced from each other to provide for pivotal movement of the forward arm 68 about the pivot rod 69 and serving to adjust the working height of the left auger 70. A similar pair of uprights 71, 72 mount a pivot rod 73 supporting a rearward arm 74 for that auger at the rear of plate 11. The distal ends of arms 68 and 74 are equipped with bearings in which the auger shaft 75 is journalled and a member 76 is rigidly attached to each arm and enables the assembly to pivot as a unit. For pivoting the auger shaft 75 a double-acting fluid motor 80, as seen in FIG. 10, employs a piston rod pivotally connected to a bracket 77 affixed to arm 68 and a cylinder pivotally connected to a lug 81 affixed to the upper surface of the carriage plate. Intermediate its ends the auger shaft 75 has keyed thereto a sprocket 82 driven by a chain 83 extending around the drive sprocket of motor 62, the upper reach of this chain passing above the member 76 and the lower reach thereof passing below that member.

Extensions 84, 85 projecting from the front and rear uprights provide for the mounting of a protective shroud (not shown) serving to protect the apparatus from material which may fall from the roof of the mine. As will be seen in FIG. 1 the top of these extensions define the profile height D of the apparatus.

As shown in FIGS. 4 and 9, the shaft 89 of the righthand auger 90 is journalled in a combined bell crank and forward arm 91 and in a rearward arm 92. At their distal ends, these arms are rigidly joined by a member 94 which causes them to pivot as a unit. The carriage plate has attached thereto a pair of spaced uprights 96, 97 in which a short shaft 98 is journalled for rotation and which has an idler gear 99 attached thereto. This gear is constantly in engagement with a gear 100 keyed to auger shaft 89 and which causes that auger shaft to turn in a counter direction to the rotation of the companion auger shaft 75. Also keyed to shaft 98 is a sprocket 101 over which a chain 102 is directed, this chain in turn being driven by sprocket 64 associated with motor 62.

Additional spaced uprights 105, 106 and 107 rigidly attached to the carriage plate provide a mounting for a winch shaft 109 coaxially arranged with respect to shaft 98. A small shaft 110 mounted at its ends in uprights 106 and 107 and having pulley guides 111, 112 suitably keyed thereto and located closely adjacent the carriage plate is provided for the following purpose. As best shown in FIGS. 1 and 2, a first cable 115 is anchored at one end in an abutment 116 at the extreme left edge of the base plate 13 and a second cable 117 is anchored at one end at the extreme right edge of that base plate, the abutments having sufficient height to permit the cables to be stretched above and close to the movable carriage plate 11. These cables after passing the pulley guides are then wrapped helically around winch shaft 109 in opposite directions and have their innr ends rigidly affixed to that winch shaft whereupon rotation of that shaft pays out one cable and rewinds the other. Since the stretched cables lie close to the carriage plate, no interference therewith can occur when the auger shafts are pivoted downwardly as when a downwardly sloping cut by the augers may be desired. Moreover, the resulting coaction of the base plate, the carriage, and the cables together with the stepping of the assembly, as later to be described, make it possible to conduct the mining operation without requiring an operator to accompany the machine into the mine.

For the purpose of rotating the winch shaft and thereby reciprocating the carriage along the guides 12 and 21, a suitable reversible fluid motor 120 and gear box are mounted on the carriage plate. A sprocket 121 driven thereby in turn drives a chain 122 which engages with a sprocket 123 at the end of the winch shaft 109. A suitable shroud (not shown) encloses these sprockets and chain and protects the same against coal being loaded into the orbital conveyor.

Passing now to FIG. 10, a preferred arrangement for adjusting the axis of the righthand auger 90 without increasing the profile height D of the apparatus includes the mounting of the combined bellcrank and arm 91 pivotally upon the winch shaft 109 between the uprights 105 and 106. The shorter arm 130 of the bellcrank is pivotable adjacent the carriage plate 11 and is pivotally connected to the piston rod of a dual-acting fluid motor 131 the cylinder of which is pivotally attached to an abutment 132 rigidly affixed to the carriage plate. Actuation of this motor accordingly raises or lowers the shaft 89 of the righthand auger.

Referring now to FIGS. 2 and 11, the intermediate inclined floor plates 41, 43 and canted shelf 40 are supported by suitable braces of which 140 and 141 are shown (FIG. 11). Adjacent the right rear corner of base plate 13 a reversible fluid motor 142 is mounted with a drive shaft inclined upwardly and carrying drive sprocket 24 engaging with chain 23 of the orbital conveyor. Adjacent this drive sprocket the opening 143 in the orbital conveyor floor is located and therebeneath the forward end of the bridge conveyor 46 is suitably attached to the base plate 13. As will be understood, the elongated bridge conveyor is driven at its rearward end as by means of a suitable fluid motor 144 (FIG. 12) and as the base plate is moved forwardly or rearwardly the bridge conveyor is simultaneously shifted. In similar fashion the inclined floor plate 41 and the shelf 40 are supported by braces at the left rear corner of the base plate, and the idler sprocket 29 is mounted with its shaft likewise inclined upwardly to engage with the chain of the orbital conveyor. The height of the thus described assembly does not exceed the dimension D.

For the purpose of advancing or retracting the base plate with its attached bridge conveyor, a conventional stepping means is employed comprising a skid plate 150 having a pair of abutments 151, 152 on which a pair of parallel double-acting cylinders 153, 154 are pivotally attached. Piston rods 155, 156 extending from the cylinders are pivotally attached at their distal ends to abutments 157, 158 adjacent the rear edge of the base plate 13. The effective length of extension of these rods from the cylinders is slightly less than the distance to which the augers can be sumped into the mine face.

Also mounted on the skid plate is a pair of spaced double-acting vertically disposed cylinders 160, 161 having piston rods projecting upwardly and pivotally attached to roof plates 162, 163 of substantial areas. Conveniently, an open end box housing 164 may be located at the rear edge of the skid plate and the several fluid pressure conduits serving the motors on the skid plate, base plate, and carriage may be grouped within this housing (two such conduits being indicated in FIG. 2) to avoid entanglement and to permit a more effective movement of the mining apparatus.

Reference now is made to FIGS. 12 and 13 showing a suitable system for operating the apparatus and indicating the comparative simplicity of the control system. A pump 170, preferably of a variable volume type, driven by a large motor 171 and located externally of the mine draws fluid from a reservoir 172 and supplies it to a first manifold conduit 173 leading into the mine at a pressure of, for example, about 1,500-2,000 psi. A branch conduit 174 controlled by a valve 175 leads to the motor 144 at the rear of the bridge conveyor and disposed nearer the mouth of the mine than the other motors of the apparatus. A second manifold conduit 176 extends to the skid plate and has a third return manifold conduit 177 leading to the reservoir 172 outside the mine. Connected to the second and third manifold conduits are branch conduits 179, 180 under control of valve 181 and communicating with the respective ends of the left thrust cylinder 153. Likewise connected to the second and third manifold conduits are branch conduits 182, 183 under control of valve 184 and communicating with the respective ends of the right thrust cylinder 154. Associated with the respective valves 181 and 184 are conventional pressure compensated flow control valves indicated generally at 178 and 178A.

Moreover, branch conduits 190, 191 under control of valve 192 communicate the second and third manifold conduits with the roof jack motors 160, 161 through secondary manifold conduits 193, 194 thereby to effect simultaneous movement of these roof jack motors under control of a single valve.

Also connected to the second and third manifold conduits are branch conduits 195, 196 under control of a directional and pressure compensated valve arrangement 197 and communicating with the reversible motor 142 which drives the sprocket 24 for the orbital conveyor. A fourth manifold conduit 200 extends to the carriage and has a fifth return manifold conduit 201 leading to the reservoir 172 outside the mine. A branch conduit 203 under control of a directional and pressure compensated valve arrangement 204 supplies fluid to the auger-driving motor 62 and returns fluid therefrom to the fifth manifold conduit 201 through branch conduit 205. Through a branch conduit 210 fluid is supplied from the fourth manifold conduit under control of a directional and pressure compensated valve arrangement 211 to the winch motor 120 and is returned by branch conduit 212 to the fifth return manifold conduit 201.

Likewise through a branch conduit 213 fluid is supplied from the fourth manifold conduit under control of a directional and pressure compensated valve arrangement 214 to the left auger-adjusting motor 80 and is returned by branch conduit 215 to manifold conduit 201. In addition, through a branch conduit 216 fluid is supplied from the branch conduit 200 under control of a directional and pressure compensated valve arrangement 217 to the right auger-adjusting motor 131 and is returned by branch conduit 218 to manifold conduit 201. Each of the valves 181, 184, 192, 214 and 217 may be the conventional Vickers XM--DG4S4--012C--50 type defined as 4 way, 3 position, solenoid actuated, spring centered, closed center whereas the valves 175, 197 and 211 for their respective motors may be Vickers XM--DG4S4--0133C--50 type defined as 4 way, 3 position, solenoid actuated, spring centered, motor spool.

For the more powerful auger motor 62 the valve 204 preferably is the Vickers XM--DG5S4--0633--C--50 type defined as 4 way, 3 position, solenoid pilot actuated, spring centered, motor spool type, and for the protection of the system a valve 220 which may be the Vickers CG5--102A--C type defined as relief valve, solenoid vented is provided and is adapted to vent into reservoir 172.

As shown in FIG. 13, a control panel 225 indicated by dotted lines is provided for use by the operator in controlling the mining operation. This normally is located outside the mine, although if desired and feasible (as when seams of more than the defined `low` height are being mined), it may be moved into the mine accompanied by an operator. Since no electrical motors within the mine are to be employed and since the only electrical energy required is for operation of the solenoids of the valves, a relatively safe source of low voltage current, for example 24 volts D.C., is supplied to the control panel through conductors 226, 227.

METHOD OF OPERATION

The procedure to be followed in mining coal with the apparatus of the invention may best be described as applied to surface entry mining and involves at the beginning the provision of a ledge and a sufficient opening into the seam to dispose within that seam the base plate 13, and with a suitable temporary abutment being provided for withstanding the forces generated at the beginning of auger rotation. After starting the pump motor 171 outside the mine the described fluid pressure system is filled with fluid, and the initial cuts by the augers can be made and sufficient coal excavated to provide room for the skid plate. The operator then closes switch 230 (FIG. 13) in the proper direction to shift valve 192 and to cause the two roof jack motors 160, 161 to engage their roof plates against the roof and to force skid plate 150 into tight engagement with the mine floor thereby to provide a rigid abutment inherent with the apparatus and against which auger-translating forces may thereafter be applied. Next the switch 231 is closed in the proper direction to shift valve 204 and to cause the auger motor 62 to rotate and to drive the augers by means of chains 83 and 102. As will be understood, at this time the forward edge 54 of the base plate is slightly outward of the vertical face of the seam and the two augers are fully sumped into the seam. Thereafter, the switch 232 is closed in the proper direction to shift valve 197 and to cause the orbital conveyor motor to rotate and to drive the sprocket 24 in engagement with chain 23 thus causing movement of the orbital conveyor. Next switch 233 is closed in the proper direction to shift valve 175 and to cause the motor 144 to drive the bridge conveyor 46.

Then the switch 234 is closed in the proper direction to shift valve 211 and to cause the winch motor 120 to turn in the direction causing the carriage to move from left to right. Assuming now that the diameter of the augers is twenty inches and that the point of tangency of auger 70 is in the plane of the base plate 13 and slightly to the left of that plate, and with the point of tangency of the auger 90 in the same plane, the winch shaft upon rotation will wind up the cable 117 and cause the right hand auger to be moved to position 18 and the lefthand auger to be moved to position 14. A complete cut of 20 inches is then made and while the augers are so being translated the dislodged coal is moved rearwardly and spilled over the front guide 12 into the orbital conveyor which like the bridge conveyor, is carrying away the coal. This represents one alternative use of the apparatus as when the seam thickness is equal to or only slightly greater than the diameter of the augers. In this situation, after the carriage reaches its righthandmost position switch 234 is restored to off position and the winch motor comes to rest.

Then switch 230 is closed in the proper direction to cause valve 192 to shift and to retract the pistons in cylinders 160, 161 thus disengaging the roof plates from the mine roof. Next switches 235 and 236 are closed in the proper direction to cause valves 181 and 184, respectively, to shift and to draw the cylinders 153, 154 toward the base plate. As will be understood, the weight of the base plate which, for example, may be 12 feet in width, and the weight of the carriage and its superstructure is far greater than the weight of the skid plate and its attached parts. After skid plate 150 is drawn to near the base plate, switch 230 is again closed in the proper direction to cause valve 192 to shift and again to clamp the skid plate to the mine floor and the roof plates 162, 163 to the roof. Thereafter, with the augers still rotating and the orbital and bridge conveyors still travelling switches 235 and 236 are closed in the proper direction to cause valves 181, 184 respectively to shift and to extend the piston rods 155 and 156. This action now causes the entire base plate 13 and the supported carriage to move toward the mine face and as the base plate is so moved it pulls forward the bridge conveyor. Any loose coal lying between the mine face and the edge 54 of the base plate is cammed up over the guide 12 and falls into the moving orbital conveyor and as the assembly is so moved forwardly the two rotating augers are sumped into the mine face in readiness for the next traverse of the carriage. With the auger fully sumped into the seam the switch 234 is then closed in the proper direction to cause valve 211 to shift and to cause the winch motor to rotate in the opposite direction. As this occurs, the cable 115 is wound on the shaft 109 and the carriage is moved from right to left with the left auger again moving to position 16 and the right auger again moving to position 14. Thereafter the apparatus may be stepped forwardly as described to initiate another cycle of operation.

When the mining has proceeded to the full extent of the power provided by the hydraulic system, the several switches 231, 232, 233, 234, 237 and 238 are opened thus bringing their corresponding motors to rest. Switches 213, 235 and 236 are then periodically manipulated to walk the apparatus from the mine opening.

Although the apparatus is especially suited for mining low seams it also is capable of mining thicker seams as shown in FIG. 1 and when this is desired a different sequence of operation is followed. Assuming that a seam of 30 inches is present and that the auger diameter is 20 inches, the cycle would begin with the lefthand auger sumped into the thick seam at position 16 (FIG. 1). The switch 237 would then be closed in the proper direction to cause valve 217 to shift and to cause fluid to be supplied to motor 131 in such way as to extend the piston rod thereof. Extension of this rod acting in the bell crank leg 130 pivots the auger-supporting arm 91 upwardly and brings the rotating auger 90 into position 15 in the coal seam. Switch 234 is then closed in the proper direction as above described and the winch motor then moves the carriage to the right until the righthand auger reaches position 17 and the lefthand auger reaches position 14. Then with the augers still rotating and the winch at rest, switch 237 is closed in the proper direction to shift valve 217 and to retract the piston in the cylinder of motor 131 whereupon the auger 90 pivots downwardly to position 18 making an arcuate cut RC in the seam during this movement. With the carriage still disposed at its extreme righthand position, switch 238 is then closed in the proper direction to shift valve 214 and to extend the piston rod in the cylinder of motor 80 whereupon the auger 70 pivots upwardly to position 19.

Switch 234 is then closed in the proper direction to shift valve 211 and to actuate the winch motor which then moves the carriage to the left. During this movement the auger 90 cuts the coal in the seam between positions 18 and 14 and the auger 70 cuts the coal between positions 19 and 20. When the carriage reaches its leftmost position, switch 238 is then closed in the proper direction to shift valve 214 and to retract the piston rod in the cylinder of motor 80 whereupon the auger 70 pivots downwardly to position 16 making an arcuate cut LC in the seam during this movement.

As shown by FIGS. 12 and 13, closing of an emergency switch 240 at any time serves to vent the pressure fluid system and to bring the mining apparatus to a halt.

Having generally described the normal mining operation it will be apparent to those skilled in the art that the apparatus possesses valuable capabilities not yet described. For example, in the event that an object falls from the mine roof and acts to clog movement of the orbital conveyor in its passage beneath the carriage plate it is a simple matter to shift switch 232 so as to shift valve 197 in the proper direction to reverse the rotation of motor 142. The orbital conveyor can travel in either direction although its flights propel the coal more efficiently in the clockwise direction of FIG. 2. However, when motor 142 is reversed the drive sprocket 24 turns in a reverse direction and the conveyor can carry the obstructing object to the opening 143.

Frequently, the seam being mined will be found to slope upwardly or downwardly from a horizontal plane. The mounting of the dual auger shafts in arms which may be selectively pivoted upwardly or downwardly permits the apparatus to be accomodated to sloping seams. As will be understood, the normal position of the pistons in the cylinders of motors 80 and 131 thus will be located intermediate the ends of those cylinders.

The arrangement of the various elements of the apparatus is coordinated to effect a compact and relatively simple machine of low profile and which is well suited for use as a robot controlled from the exterior of the mine. Any suitable means for sensing the several phases of operation and for communicating the necessary information to the operator at a remote point may be employed, and as such forms no part of the present invention.

As will be apparent, after the apparatus is installed in a mine opening a single operator can control the operation from the control panel 225. The bridge conveyor 46 can be of indeterminate length and by means of conventional gearing one section of conveyor can be attached to another in order to lengthen the same, the lengthened conveyor still being driven by the single motor 144.

The conduits supplying pressure fluid to the motors as well as the electrical conductors leading to the solenoid valves associated with those motors may readily be bundled and pulled forwardly as the apparatus is stepped into the mine; these conduits and conductors being spaced from the bridge conveyor and being withdrawn from the mine from a station outside the mine when the apparatus is stepped from the mine.

As will be understood, other means for quickly withdrawing the apparatus from the mine without relying upon the step-by-step retraction may be employed without departing from the invention. For example, cables (not shown) attached to the apparatus and extending to a winch located outside the mine could be employed.

Moreover, if an operator should accompany the apparatus into the mine he is not required to occupy a position close to the base plate where the likelihood of roof falls is greatest. Rather he may move forwardly well behind the augers and take conventional precautions, such as installing roof support plates, as he moves forwardly thus to insure his safety under supported roof conditions.

The apparatus is of a size making it economically feasible to mine low seams and, as an example, a cut in excess of 12 feet in width and to a depth of several hundred feet into the seam may be made before the apparatus has to be withdrawn for making a similar cut from the same seam. Furthermore, in contrast with conventional auger mining much less labor is required for the production of a given quantity of coal.

Having disclosed a preferred form of mining apparatus, it will be understood that the invention may be embodied in other forms than that described as the preferred form, and without departing from the scope of the appended claims.

Claims

What is claimed is:

1. Apparatus for mining coal or the like including, a base plate having a low profile forward guide and a low profile rearward guide affixed to the upper surface thereof, a low profile carriage supported on said base plate and movable transversely thereof along said guides, a pair of spaced augers projecting forwardly of said base plate and mounted on said carriage with their axes parallel at all times and directed toward the mine face normally to the path of movement of said carriage, the rear portions of said augers being at all times in advance of the forward edge of said base plate, low profile motor means mounted on said carriage for driving said augers and with its lowermost portion disposed adjacent said base plate, means mounted on said carriage and coacting with said base plate for moving said carriage transversely of said base plate, a low profile orbital conveyor movable along said base plate beneath said carriage rearwardly of said forward guide for moving material dislodged by said augers and spilling over said forward guide, means supported by said base plate for driving said conveyor, and means for moving said apparatus selectively toward and from the mine face.

2. Apparatus as defined in claim 1 wherein said means for moving said carriage comprises a winch mounted on said carriage and including cables attached at their ends to said base plate adjacent the side edges of said base plate.

3. Apparatus as defined in claim 2 wherein said cables extend adjacent the plane of said carriage and over the side reaches of said orbital conveyor.

4. Apparatus as defined in claim 1 wherein the rearward guide is shorter than the forward guide and is disposed to provide space for movement of said orbital conveyor around its respective ends.

5. Apparatus as defined in claim 4 wherein said forward guide serves as a confining wall along which the flights of said orbital conveyor are moved.

6. Apparatus as defined in claim 4 wherein said guides comprise L-shaped members with the respective upper legs thereof facing from each other.

7. Apparatus as defined in claim 6 wherein said carriage includes a plurality of rollers mounted thereon adjacent its forward edge and movable in contact with the edge of the upper leg of said forward guide.

8. Apparatus as defined in claim 6 wherein said carriage includes a plurality of rollers mounted thereon adjacent its forward edge and movable in contact with said base plate and beneath the upper leg of said forward guide.

9. Apparatus as defined in claim 1 including an elevated and canted shelf supported above the rear portion of said base plate and along which said orbital conveyor is moved in its passage to and from its movement along said base plate beneath said carriage.

10. Apparatus as defined in claim 9 including an opening in said elevated shelf through which said orbital conveyor discharges its contents.

11. Apparatus as defined in claim 10 including a bridge conveyor having its forward end attached to said base plate and disposed beneath said opening.

12. Apparatus as defined in claim 1 wherein said means for driving said conveyor comprises a reversible motor driving a sprocket in engagement with a chain of said conveyor and adapted to drive said conveyor in either direction.

13. Apparatus as defined in claim 1 wherein said means for moving said apparatus toward and from the mine face includes a skid plate connected exclusively to said base plate by a plurality of selectively extendible and retractable piston rods extending horizontally from cylinders of fluid motors mounted on said skid plate, and a plurality of roof plates connected to piston rods of fluid motors mounted on said skid plate and adapted selectively to be engaged and disengaged from the mine roof.

14. Apparatus for mining coal or the like including, a base plate, a low profile carriage supported on said base plate and movable transversely thereof, first and second spaced augers projecting forwardly of said base plate and mounted on said carriage with their axes parallel to the plane of said base plate at all times and directed toward the mine face normally to the direction of movement of said carriage, the respective augers having first and second drive shafts, auger-pivoting means for selectively moving said augers upwardly and downwardly, means mounted on said carriage for actuating said auger-pivoting means, the rear portions of said augers being at all times in advance of the forward edge of said base plate, means mounted on said carriage for driving said augers, means mounted on said carriage and coacting with said base plate for moving said carriage transversely of said plate, a low profile orbital conveyor movable along said base plate beneath said carriage for moving material dislodged by said augers, means supported on said base plate for driving said conveyor, and means for moving said apparatus selectively toward and from the mine face.

15. Apparatus as defined in claim 14 including a low profile superstructure having uprights mounted on said carriage and pivotally mounting a pair of interconnected spaced arms journalling said first drive shaft and serving as the auger-pivoting means for said first auger, and a double-acting fluid motor mounted on said carriage and having a cylinder and piston rod connecting said carriage to said interconnected arms.

16. Apparatus as defined in claim 14 including a superstructure having uprights mounted on said carriage and supporting a pair of coaxial separate shafts arranged parallel to said second drive shaft a pair of interconnected spaced arms serving as the auger-pivoting means for said second auger and mounted for pivotal movement with one arm pivoting about one of said coaxial shafts and the other arm pivoting about the other of said coaxial shafts, and a double-acting fluid motor mounted on said carriage and having a cylinder and piston rod connecting said carriage to said interconnected arms.

17. Apparatus as defined in claim 16 wherein one of said arms includes a bell crank portion having a lower end connected to the cylinder and piston rod of said motor.

18. Apparatus as defined in claim 16 including a reversible fluid pressure motor mounted on said carriage and including means for driving one of said coaxial shafts independently of the other coaxial shaft.

19. Apparatus as defined in claim 18 wherein said one of said coaxial shafts comprises a winch drum and said means coacting with said base plate comprises a pair of cables wound on said drum and stretching adjacent the surface of said carriage to fixed abutments respectively mounted at the side edges of said base plate.

20. Apparatus as defined in claim 19 including a pair of pulley guides mounted adjacent the carriage plate beneath said winch drive and around which the respective cables are passed.

21. Apparatus as defined in claim 16 wherein said auger-driving means comprises a fluid pressure motor mounted centrally of said carriage and driving a shaft provided with drive sprockets at each end, one of said drive sprockets driving a first chain engaging with a sprocket fixed to the shaft of one of said augers and the other of said drive sprockets driving a chain engaging with a sprocket fixed to one of said coaxial shafts, an auger-driving gear fixed to the shaft of the other of said augers, and an idler gear fixed to said chain-driven coaxial shaft and in mesh with said auger-driving gear thereby to produce counter-rotation of the augers.

22. A low profile remotely controlled apparatus for mining coal or the like in low seams without requiring the presence of an operator adjacent the mine face and including a base plate, a low profile carriage supported on said base plate and movable transversely thereof, a pair of spaced augers projecting forwardly of said base plate and mounted on said carriage, the rear portions of said augers being at all times in advance of the forward edge of said base plate, a fluid pressure motor mounted on said carriage for driving said augers, means including a winch driven by a reversible fluid pressure motor mounted on said carriage and having cables attached at their ends to said base plate for moving said carriage transversely of said base plate, a low profile orbital conveyor movable along said base plate beneath said carriage for moving material dislodged by said augers, a fluid pressure motor supported on said base plate for driving said conveyor, a skid plate having roof plates disposed thereabove, a plurality of double-acting fluid pressure cylinders having piston rods joining said base plate and said skid plate and forming the exclusive means for varying the spacing between said plates, a plurality of double-acting fluid pressure cylinders having piston rods joining said skid plate and the corresponding roof plates, a fluid pressure source located externally of the mine and having conduits leading to and from the respective motors, each of said motors having a solenoid operated valve controlling the flow of fluid through the conduits connected to the respective motor, and an electrical system operable from a point remote from said base plate and having switches serving to control the settings of the respective solenoids of said valves.

23. An apparatus as defined in claim 22 including a bridge conveyor connected at its forward end to said base plate and receiving material discharged by said orbital conveyor, a fluid pressure motor for driving said bridge conveyor and receiving fluid through a conduit from said pressure source, a solenoid-operated valve controlling flow of fluid to the bridge conveyor motor, and a switch in said electrical system for controlling the setting of the solenoid of the valve for the bridge conveyor motor.

24. An apparatus as defined in claim 22 wherein said electrical system employs low voltage direct current and comprises the sole usage of electricity required for operation of the apparatus within the mine.