US2904319A - Continuous miner with automatic roof support - Google Patents

Description

2 Sheets-Sheet 1 Sept. 15, 1959 J. 5. NEWTON CONTINUOUS MINER WITH AUTOMATIC ROOF SUPPORT Filed June 2, 1958 ATTORNEY n .lmw o N% m W N N E m WWW E VS Q m n Q 2 I m w 4 B J JR mv m 4 MN vw wm 3 Km I 1% mm 3 H 3 F g u m N m r \T A m Nv I I m mm W Q I 2 Q I Q Q I p? PF 1 T Kw mm \w M a wm mm W T Sept. 15, 1959 J. s. NEWTON 2,904,319

CONTINUOUS MINER WITH AUTOMATIC ROOF SUPPORT Filed June 2, 1958 2 Sheets-Sheet 2 ATTORNEY United States Patent CONTINUOUS MINER WITH AUTOMATIC ROOF SUPPORT John S. Newton, Glen Ellyn, 11]., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Application June 2, 1958, Serial No. 739,227 Claims. (Cl. 262--7) This invention relates generally to boring type continuous mining machines and more particularly to apparatus associated therewith for supporting the roof of a tunnel mined by such a machine.

Prior to the advent of continuous mining machines, much of the mining in this country was done by a cyclic process employing principally three machines, an undercutter, a drill and a ladder. These machines were used one after the other, and were narrow enough to permit the placing of posts alongside the machine to support the roof. These machines, whether cutter, drill or loader, were adapted to traverse across the width of the face. In some cases the body of the machine remained intermediate the posts while the head moved transversely across the face and in other cases the whole machine moved under the protection of temporarily placed mechanical roof jacks.

In order to realize the fullest benefits of continuous mining, the trend is to provide machines which attack the whole face at once leading to wider machines. Where wider machines are used, the posts must be set nearer the rib, thereby limiting their effectiveness.

Recent advances in the art of roof control have dis closed that it is not necessary to support the whole weight of earthy material above a mine entry. In most cases, this material lies in strata which are occasionally interrupted by faults. The use of roof bolts secures these strata together one above the other in the manner of a composite beam, thereby causing each to contribute to the strength of the other, to form a natural beam capable of supporting its own weight and the weight of non-laminar faults. Further, where it is possible to secure this heterogeneous material together in one rigid mass, before yielding has occurred, an added benefit is derived from the adhesive effect of its interstitial surfaces.

The present invention contemplates the provision of a roof supporting canopy extending rearwardly from the face to support overlying strata as material is removed in the mining process.

Therefore, it is a principal object of the present invention to provide a temporary roof supporting means capable of engaging and supporting the roof of a mine, as soon as it is defined, and capable of maintaining such support along -a span of the roof to a point where permanent supporting means can be employed. A further object is to provide a supporting means for a heterogeneous mine roof capable of maintaining the cohesive mass in undisturbed relation, for an interval, until permanent supporting means is provided. Still a further object is to provide a means for uninterrupted roof control in combination with a continuous mining machine.

A primary object is to support one end of the canopy on the cutter bar that defines the roof so as to provide inherent alignment between the cutter bar and canopy thereby obviating the necessity of making frequent adjustments in the height of the canopy to accommodate changes in effective working height of the cutter bar.

Other objects and advantages will be seen from the following description together with the drawings in which:

Figure 1 is a side elevation view of a boring type continuous mining machine employing the present invention;

Figure 2 is a fragmentary plan view, to enlarged scale, taken along the line 2-2 of Figure l; and

Figure 3 is a diagram of an operating circuit for controlling the canopy of the present invention.

Referring to Figure 1, there is shown a boring type continuous mining machine, designated by the numeral 10, and an auxiliary roof bolting device 11. The body of machine 10 is made up of two major sub-assemblies, a mobile chassis 12 and an adjustable superstructure 13. Mobile chassis 12 is mounted for movement on tractor treads 14 which are driven in a manner well known in the art and will not be further described. The chassis 12 also carries a conveyor 16 for transporting the mined material from the heads to a haulage device at the rear of the machine. In addition, many of the motors, pumps, speed reducers, oil tanks, and control devices are mounted on the chassis 12.

The superstructure 13 is adjustably supported above chassis 12 on jacks 17 and 18. superstructure 13 includes a speed reducer in housing .19 which drives a plurality of rotary boring heads 21, and cutter chain 27 guided in a pair of cutter or trimmer bars 22 and 23. The boring heads 21, cutter chain 27 and bars 22 and 23 together comprise a mining and dislodging head 15. Boring heads 21 cut the major portion of the seam and cutter bars 22 and 23 cut and define the roof and floor respectively of the entry. Cutter bars 22 and 23 are vertically adjustable relative to superstructure 13 by means of jacks 24 and 26. The cutting or trimming is actually done by cutter chain 27 which runs in a slot in cutter bars 22 and 23.

Upper trimmer bar 22 has ears 27, 28 and 29 extending rearwardly therefrom to which a pair of roof supporting canopies 8 and 9 are articulately connected. This is an extremely important part of the present invention for it enables the canopies to be automatically maintained at the level of the roof defined by the cutter bar (see Figures 1 and 2). The canopies have frames 31 and 32 which are alike, and therefore only frame 31 will be described in detail. Frame 31 has a pair of forwardly extending ears 33 and 34 which are pivotally supported on pins 36 and 37 in cars 27 and 28 to form a pivotal connection between the frames 31 and trimmer bar 22. A set of cylindrical rollers 38, for engagement with the roof, are rotatably journaled in frame 31. Jack 39 is mounted on superstructure 13 by means of pin 42 and in turn is connected to and supports frame 31 by means of pin 41.

The roof bolting device 11 is of a commercial type and will not be described in detail. Briefly, a powered chuck which can be used for driving a drill or running a nut, is mounted for vertical translation to and from the room. A drill bit and rod are used in the chuck to drill a hole in the roof, after which the bit and rod are removed and a roof bolt is inserted. When the roof bolt is inserted, a nut is tightened to pin the overlying strata together. The Whole roof bolting device 11 is mounted on skid 43 and can be pulled along the floor by cable 46 attached to a winch in its base which is not otherwise shown. As shown in Figure 1, cable 46 is attached to plate 47 on chassis 12 of the continuous miner. A ramp 44 on chassis 12 cooperates with skid 43 under roof bolting device 11 so that it can be hauled aboard the miner when the miner is retreating. Ordinarily, the bolting device 11 is pulled to a position where a bolt is to be installed and then remains stationary to perform the drilling and bolting operation while the miner continues to advance forwardly.

Now, with reference to Figure 3, tank 48 supplies fluid to pump 49 through line 51. Pump 49' supplies pressure fluid tothree position. control valve 52 by line 53. Relief valve 56 is connected in parallel across pump 49 by means of lines 54 and 57 to protect the pump when the circuit is blocked.

In one position of valve 52, pressure .fluid is supplied to line 58 which enters metering valve 59, depressing a spool 61 causing it to engage and displace metering plug 62. Fluid in line 58 passes through valve 59, to line 63, to the rod end of piston 64 in jack 39. Fluid is expelled from jack 39 by the head end of piston 64 through line 66, and branch lines 67 and 68. Relief valve 69 is set ata high pressure, and since metering plug 62 has been previously unseated, fluid flows through line 71, shuttle valve 72, and line 73 to low pressure relief valve 74,

where it flows back to tank 48 through line 76, or line 84 and valve 52 depending upon whether the pressure in line 73 is greater or less than the setting of the valve 74.

Now consider the situation, where control valve 52 is in a neutral position such that no pressure fluid occurs in line 58. Under this condition, if the rollers 38 of the canopy encounter an irregularity in the roof such that piston 64 is forced downwardly, fluid is forced through lines 66 and 68 to metering valve 59. Since no pressure occurs in line 58, metering plug 62 remains in place and the fluid from line 68 must pass through orifice 77 which restricts its flow. As long as the descent of piston 64 is gradual, fluid will flow through orifice 77, line 71, shuttle valve 72, and line 73 to low relief valve 74 which will permit the fluid to escape to tank through line 76.

In the situation where control valve 52 is in neutral and asudden fall occurs on the canopy, piston 64 is again depressed forcing fluid from the head end through line 66. The surge of fluid created by a sudden fall is greater than can be metered through orifice 77 in metering valve 59 and pressure builds up in lines 67 and 68 suificient to flow through high pressure relief valve 69. Fluid flowing through high relief valve 69 goes through lines 78 and 79 to an end of spool 81 in shuttle valve 72, moving spool 81 to the right as. viewed in- Figure 3. When spool 81 is in the right hand position, flow from line 71 and consequently lines 66 and 68 is blocked. Therefore, a sudden roof fall blocks all flow from jack 39 to hold the. canopy in place. When the roof has been secured after a fall, the circuit can be restored to operative condition by opening valve 82 to. break the fluid column holding spool 81 in the right hand position.

When the fluid column in lines 78 and 79 has been broken, control valve 52, if put in the other or rise position, will supply pressure fluid to line 83 to restore spool 81 to the left hand position. Thereafter fluid flows through line 84 through low relief valve 74, which now acts as a pressure reducing valve, to the line 73. Fluid now flows through the circuit in a reverse direction through shuttle valve 72, and line 71 to unseat metering plug 62 in metering valve 59. Unseating plug 62 allows full flow to the head end of piston 64 to raise the rear end of the canopy into engagement with the roof.

Low relief valve 74 is regulated to maintain a pressure inline 73 sufiicient to cause the canopy to bear against the roof with enough force to hold the overlying strata in unyielding relation to each other. When a pressure greater than this setting occurs. in line 73 or line 84, fluid is released through line 76 to reduce the operating pressure to the correct value.

Where the control valve 52 is left in the rise position and. the canopy is forced downwardly by external forces, the circuit operates much as it does when the control valve 52 is in neutral except that the pressure generated in the jack 39 by piston 64 is greater than and cancels the pressure in line 71' as regulated by the pressure reducing relief valve 74; An added advantage of leaving the control valve 52 in the rise position while operating the machine, is that where the canopy encounters a temporary obstruction and glides under it, it will be returned to full contact with the roof as soon as the obstruction is passed.

In operation, the machine advances forwardly into the seam as its mining head reduces the solid seam to broken lumps. Boring heads 21 remove the major portion of the seam by boring a group of holes, while the remainder of the seam is trimmed and the floor and roof are defined by cutter bars 23 and 22. Rollers 38 in frames 31 and 32 engage and support the roof over a considerable area as soon as it is defined. Since immediate roof support is provided, the overlying strata are not permitted to yield and therefore have little tendency to fracture.

Roof bolting device 11 can be engaged with the roof near the end of the canopy and while this position is being drilled and bolted, the mining machine can continue with its forward advance. Upon the completion of bolting in one position, the roof bolting device can then be pulled forward to the end of the canopy to repeat the operation. The combination of a roof supporting canopy and roof bolting device, together with a continuous mining machine, provides for a safer roof than where temporary supporting structures are installed and moved about indiscriminately, or where permanent roof bolting means are installed after the roof has had an opportunity to yield and fracture.

While this invention has been described in terms of a preferred embodiment, it will be understood that various changes and modifications may be. made without departmg from the spirit and scope of the claims here appended.

I claim:

1. In a continuous mining machine, a mobile body having a mining and dislodging head including a cutter bar adapted to define the roof of an entry, the improvement comprising: a roof-engageable canopy, an articulated connection between one portion of said canopy and sa d cutter bar, and support means interposed between said body and another portion of said canopy, said support means including means actuatable to urge said other portion of the canopy toward the roof.

2 In a continuous mining machine, a mobile body having a mining and dislodging head including a cutter bar adapted to define the roof of an entry, means for adjLlSlll'lg the position of the cutter bar relative to the body, the improvement comprising: a pair of roof engageable canopies, an articulated connection between one portion of each of said canopies and said cutter bar, and support means interposed between said body and another portion of each of said canopies including means actuatable to press said other portions of the canopies upward against the roof.

3. In a continuous mining machine having a mobile body with a mining and dislodging head supported thereon, said head including a cutter bar adapted to define the roof of an entry, said head being adjustable relative to the body and extending transversely of the length of the body, the improvement comprising: a roof engageable canopy, a pivotal connection between one portion of said canopy and said cutter bar, and jack means interposed between said body and another portion of said canopy including means actuatable to press said other portion of the canopy upward against the roof.

4. In a continuous mining machine, mounted upon a mobile body, having a mining and dislodging head including a cutter bar adapted to define the roof of an entry, the improvement comprising: a roof engageable canopy, a pivotal connection between a forward portion of said canopy and said cutter bar, a fluid pressure jack interposed between said body and a rearward portion of said canopy, and a source of fluid pressure connected to said jack including means actuatable to press said rearward portion of the canopy upward against the' roof while the forward portion is held at the roof level by the cutter bar.

5. In a continuous mining machine, mountedupon a mobile body, having a mining and dislodging head including a cutter bar adapted to define the roof of an entry, said cutter bar extending transversely of the body and being movable for adjustment relative to the body, the improvement comprising: a roof engageable canopy, a pivotal connection between one end portion of said canopy and said cutter bar, fluid pressure jack means interposed between said body and another end portion of said canopy, a source of fluid pressure connected to said jack 6 means to relieve fluid therefrom.

References Cited in the file of this patent UNITED STATES PATENTS Joy June 28, 1955 2,756,034 Calder July 24, 1956

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