Mine drilling apparatus and method
BACKGROUND OF THE INVENTION 
     Many types of mining equipment have been proposed for mining coal and other minerals economically and expeditiously. The coal is normally cut-out of a solid vein and dropped on a conveyor to load the coal in a shuttle car or the like for transport to a remote location for processing. One type of such mining equipment has cutters mounted on rotating arms which are, in turn, mounted on a mobile vehicle which must be steered to place the cutters in position for cutting purposes. 
     Another type of mining equipment comprises a horizontally disposed auger adapted to remove soft coal in lumps with minimum fine breakage. The cuttings are carried backwardly by the auger flights to a conveyor belt or the like for loading purposes. The auger is used for mining coal from the edges of strip pits with the standard practice being to cut parallel holes, thus leaving thin pillars or ribs between the holes to support the overburden. Alternatively, a single hole may be cut from a centerline tunnel and the coal from each side thereof being thereafter drilled and blasted into it for recovery purposes. 
     One of the problems with such drilling equipment is the inability to recover a maximum amount of coal due to the cylindrical bores which are formed thereby. In addition, when the drill is lengthened up to 200 feet, for example, the auger will tend to &#34;wander&#34; and thus cause binding and related problems. Also, the auger itself is not always capable of penetrating obstructions, such as a hard rock seam or a bolder, and thus requires exotic tips on the auger or dynamiting to complete the coal recovery operation. 
     SUMMARY OF THIS INVENTION 
     An object of this invention is to overcome the above, briefly described problems by providing an improved drilling apparatus and method for recovering coal and like materials expeditiously and economically. The drilling apparatus comprises a support adapted to be moved transversely along rails and a drilling assembly has a carriage mounted on the support for longitudinal movements thereon. The drilling assembly comprises a rotatable auger, first motor means for selectively rotating the auger and a cutting edge disposed adjacent to the forward end of the auger to cooperate therewith for drilling purposes. A second motor means is interconnected between the support and the carriage for selectively moving the drilling assembly longitudinally on the support to urge the auger bit and cutting edge into cutting engagement with a coal vein, for example. 
     The cutting edge is preferably rectangular and is at least substantially disposed in a plane perpendicular relative to the longitudinal axis of the auger to form a drill hole having a rectangular and preferably square cross section. Formation of such a square cross section substantially increases the amount of coal which may be recovered in comparison to holes of circular cross section formed by conventional drilling apparatus and methods. In addition, alignment means are preferably adjustably mounted on a forward end of the drilling assembly to stabilize the same and to insure that the auger does not wander to thus form a straight-line hole to avoid binding and related problems. A plurality of the auger assemblies may be attached together in tandem to substantially increase the penetration capabilities of the drilling apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects of this invention will become apparent from the following description and accompanying drawings wherein: 
     FIG. 1 is an overview of the drilling apparatus of this invention, shown in use during a mining operation; 
     FIG. 2 is an enlarged side elevational view of the drilling apparatus; 
     FIGS. 3-6 are views taken in the direction of arrows III--III, IV--IV, V--V and VI--VI, respectively, in FIG. 2; 
     FIG. 7 is a sectional view taken in the direction of arrows VII--VII in FIG. 6; 
     FIG. 8 is an enlarged bottom plan view of a forward portion of the drilling apparatus, taken in the direction of arrows VIII--VIII in FIG. 2; and 
     FIG. 9 is a partial view similar to FIG. 2, but illustrating the capability of attaching a plurality of drilling assemblies of the drilling apparatus in tandem to increase the depth of penetration thereof during a mining operation. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a drilling apparatus 10, embodying this invention, shown in use during a mining operation. In particular, the drilling apparatus is adapted to form holes 11 during the mining of coal or the like. The recovered coal is then deposited on a continuous conveyor 12 which dumps the coal into a truck 13 or the like for transport to a remote location. 
     Referring to FIG. 2, drilling apparatus 10 comprises a support structure 14 mounted on a pair of transversely disposed and laterally spaced rails 15 for movement thereon in a conventional manner. An auger assembly 16 comprises a carriage and frame structure 17 movably mounted on support 14 for longitudinal movements in the direction of an axis X thereon. As shown in FIG. 3, carriage 17 may have two sets of rollers 18 rotatably mounted on each side thereof to engage a rail 19 of support 14 in a conventional manner. The rail thus traps the rollers on either side thereof to permit auger assembly 16 to be moved forwardly of support 14 in cantilevered relationship thereon. 
     As shown in FIGS. 2 and 4, the auger assembly further comprises a tubular and generally cylindrical shroud 20 having its rearward end secured to carriage 17 for simultaneous movement therewith. At least one roller 21 is rotatably mounted on an inboard side of a forward end of a respective rail 19 of support 14. Each roller is frustoconically shaped to engage the periphery of the shroud in line contact to aid in its extension during a drilling operation. 
     An auger 22 has a plurality of spiralled flights 23 secured on a shank 24 thereof. A replaceable drill bit 25 is attached to a forward end of shank 24 to initiate a particular drilling operation. A crescent-shaped opening 26 is formed at a rearward end of shroud 20 to permit the egress of boiled drilled materials therethrough and onto conveyor 12 (FIG. 1). 
     A cutting edge 27 is detachably secured on a forward end of shroud 20 by means, not shown, to circumvent the forward end of auger 22, as illustrated in FIGS. 2 and 5. The cutting edge is rectangular in cross section, preferably square, and is at least substantially disposed in a plane perpendicular relative to the longitudinal axis of the auger. The outside diameter of the auger is slightly less than the height and width of the cutting edge to prevent binding therebetween. 
     As shown in FIGS. 2, 6 and 7, a rearward end of shroud 20 is connected to a tubular extension 28 of carriage 17 by a plurality of circumferentially disposed U-shaped fasteners 29. The longitudinal spaced legs of each fastener engage within openings 30 and 31, formed through a sidewall of shroud 20 and through extension 28 of the carriage, respectively. An annular collar 32 is threadably mounted on extension 28 at interengaging screw threads 33 and has a plurality of longitudinally disposed slots 34 formed therethrough. As shown in FIG. 6, upon attachment of shroud 20 to extension 28 of the carriage, each slot 34 is aligned with a respective pair of openings 30 and 31 to permit fastener 29 to be dropped therein. Upon installation of the fasteners, collar 32 is rotated to misalign the slots relative to the fasteners to prevent removal thereof. 
     FIGS. 2 and 8 illustrate a pair of adjustable guide and alignment means 35 mounted on a forward end of shroud 20 to aid in stabilizing and guiding the auger assembly during a drilling operation. Each guide means comprises a slipper 36 in the form of a lever pivotally mounted on the shroud by a pivot pin 37 and substantially disposed in longitudinal alignment with cutting edge 27. A double acting hydraulic cylinder 38 is pivotally interconnected between the shroud and slipper by pivot pins 39 and 40, respectively. Thus, the cylinders may be selectively extended and retracted during a drilling operation to engage sidewalls defining a drilled hole to aid in forming a straight hole, by conventional hydraulic control means (not shown). 
     The means for rotating auger 22 and for moving the auger assembly in the direction of axis X (FIG. 2) for earth penetration purposes will now be described. An internal combustion engine 41, such as a diesel, is mounted rearwardly on support structure 14 and is adapted to actuate a hydraulic pump 42. The pump is operatively connected in a conventional manner to a hydraulic slave motor 43 by flexible lines 44 for driving an output shaft 45. 
     The output shaft is secured to a first spur gear 46 which meshes with a second spur gear 47 to selectively impart rotation thereto by operator control means, not shown. The second spur gear is secured to a countershaft 48 which has a square socket 49 secured thereto for rotation therewith. The female socket is adapted to receive a like-shaped male drive lug 50 to form a releasable coupling normally held in engagement by members 29 (FIGS. 6 and 7). 
     Thus, it can be seen that selective actuation of motor 43 will rotate auger 22 under the control of the operator. The motor is preferably reversible and is mounted on carriage 17 along with its attendant drive mechanisms for forward movement in the direction of axis X (FIG. 2) during an earth penetrating operation. A second motor means, preferably in the form of one or more double-acting hydraulic cylinders 51, preferably of the telescopic type, is pivotally interconnected between support 14 and carriage 17 by pivot pins 52 and 53, respectively. 
     The cylinder is suitably integrated in the overall hydraulic control system and is adapted to be extended and retracted by the operator by conventional control means (not shown) which coordinate with the control means for actuating motor 43 to effect the earth drilling function. In particular, extension of cylinder 51 will function to move carriage 17 forwardly to engage drill bit 25 and cutting edge 27 with the earth or a coal vein, for example, to form the square shaped cut-outs illustrated in FIG. 1. Cylinders 38 (FIGS. 2 and 8) may be selectively extended and retracted to aid in maintaining auger assembly 16 in proper alignment. 
     Referring to FIGS. 1, 2, 6, 7 and 9, upon maximum forward extension of the auger assembly on support 14, collar 32 may be rotated to expose fasteners 29 to permit their release from their respective mounting holes 30 and 31. Upon such release, cylinder 51 can be retracted to its FIG. 2 position whereby an auger extension assembly 54 can be mounted on support 14 between the rearward end of auger assembly 16 and the forward end of carriage 17. 
     As shown in FIGS. 1 and 2, a crane 55 may be employed to engage a hook 56 thereof under a chain 57 wrapped around a shaft of an auger extension 58. As shown in FIG. 9, the auger extension may be lifted and placed in axial alignment with the longitudinal axis of auger 22 whereby a male drive lug 59 secured on a rearward end of the shaft of auger 58 may engage socket 49. 
     The forward end of the shaft for auger extension 58 has a socket 60 secured on the forward end thereof to receive male drive lug 50 of auger assembly 16. Upon full forward extension and penetration of tandemly arranged auger assembly 16 and auger extension assembly 54, a second such auger extension assembly 54 may be connected in tandem to the first mentioned auger extension assembly and carriage 17 to further increase the overall penetration capabilities of the drilling apparatus.