MINING MACHINE

Abstract: A roadheader type mining machine (1) comprises a self-propelled chassis (6), an elongate boom (9) having a longitudinal axis (10), rotary cutting head (15) having a plurality of water spray nozzles (17), the boom (9) being of a two-part construction comprising one part (18) that is non-rotatable about the boom longitudinal axis (10), that is supported from one end (8) on the chassis (6), and that carries towards its other end (14) bearing means (19) for rotatably supporting another part (20), and power means (59) carried by the non-rotatable part (18) to rotate the rotatable part (20) about the boom longitudinal axis; rotatable part (20), and provided with pumping means (39) and a bearing ring (50) carried by the rotatable part (20) eccentrically with respect to the boom longitudinal axis (10), and with phased water supply to the nozzles (17) being controlled by suitable angular rotation of the rotatable part (20) about the boom longitudinal axis (10) to cause consequent rotation of the ring (50).

Description: This invention relates to a mining machine of the kind adapted to drive underground roadways, tunnels or headings, commonly known as a roadheader machine. Basically, such a machine comprises a self-propelled, crawler or wheel-mounted chassis carrying a manoeuverable boom, a terminal end of which is provided with a rotary cutting head, the latter being driven from a power unit carried by the chassis, via a transmission including a final drive shaft extending internally and longitudinally of the boom, within a stationary outer casing, and rotatably supported in bearings carried by the outer casing of the boom. The boom is power-­ manoeuverable e.g. hydraulically, under the control of the machine operator, so that the boom follows the profile required for the roadway etc. Basically, the end of the boom distal from the cutting head is mounted on a pin joint, for swinging manoeuvers in a vertical plane and about a horizontal axis (assuming the machine is located on level ground), with the pin joint mounted on a turntable arrangement for swinging manoeuvers in a horizontal plane. Apart from the cutting heads being provided with replaceable cutter picks, they are also provided with a plurality of nozzles to emit a water spray or jet, while the nozzles may in practice be mounted on the heads and/or on the picks. The water spray or jet may be for purposes such as pre-start warning, dust suppression, pick face flushing, incendive sparking elimination and, at higher pressures, water jet assisted cutting. It will be appreciated however that only a certain sector of the periphery of the cutting head is in the cut at any one time and consequently if, as is usually the case, water is emitted over 360°, a substantial proportion of the water e.g. 50%, has no beneficial effect but represents a waste of the power consumed in generating the pressure (which, in the case of water jet assisted cutting, may be of the order of 30,000 p.s.i.), apart from creating unnecessarily wet floor conditions. Attempts have been made to provide valving arrangements to achieve phased emission, but such systems have yet to be proved and are relatively complex to instal, maintain and adjust. In our co-pending European Patent Application No. 85306000.2, is described a roadheader type mining machine in which the emission of water sprays or jets may be readily phased in a desired radially extending sector by simple control of valving arrangements, basically by surrounding at least a portion of the boom with a collar rotatable about the boom longitudinal axis by power means to a selected position, the collar carrying, and/or positionally controlling, valve actuation means whereby periodic water supply to the nozzles, due to head rotation, within a selected radial sector is controllable by the valves, phased activation of which is controlled by positional adjustment of the collar to provide appropriate positional adjustment of the valve actuation means. The present invention is aimed at providing an alternative constructional system to attain the same objective viz. the provision of a readily adjustable and/or controllable phasing system. According to the present invention, there is provided a roadheader type mining machine comprising a self-propelled chassis, an elongate boom having a longitudinal axis, the boom being supported by the chassis for powered positional adjustment with respect to the chassis, a terminal end of the boom provided with a rotary cutting head drivable by a transmission, including a final drive shaft, co-axial with the boom longitudinal axis, the cutting head having a plurality of nozzles each to emit a water spray or jet, with water supplied to the nozzles along conveying conduits, the boom being of a two-­ part construction comprising one part that is non-rotatable about the boom longitudinal axis, that is supported from one end on the chassis, and that carries towards its other end bearing means for rotatably supporting another part and power means carried by the non-rotatable part to rotate the rotatable part about the boom longitudinal axis; the final drive shaft being located at least partially within the rotatable part and provided with at least one radially extending cylinder having a closed inner end and an open outer end, the or each cylinder at least partially housing a piston which is reciprocable within its cylinder, with a variable volume, pressure-generating chamber defined between a radially inner end of the piston and a closed, inner end of its cylinder, and with the radially outer end of the or each piston being in direct or indirect contact with an inner profile of a bearing ring carried by the rotatable part eccentrically with respect to the boom longitudinal axis, such that upon rotation of the drive shaft, variations in radial distance of the inner profile from the axis of rotation of the drive shaft cause reciprocation of the or each piston, and a consequent pumping effect, and with phased supply to the nozzles being controlled by suitable angular rotation of the rotatable part about the boom longitudinal axis to cause consequent rotation of the ring. Thus, the invention provides a roadheader type mining machine in which water phasing only to a selected radial sector (the cutting sector) of the cutting head, is readily attained simply by appropriate re­ positioning (by rotation) of the rotatable part from a previous angular position (appropriate to a previously selected sector) to a new, static, position that results in phased water emission over only the newly selected sector, thereby maximising the efficient use of water. Thus, with the rotary cutting head removing rock from say a left hand vertical wall from a roadway being advanced, and consequently with the rotatable part of the boom being so positioned as to attain water emission over the cutting sector of the cutting head i.e. the sector within the cut, displacement of the boom for the cutting of the right hand vertical wall will require rotation of the rotatable part of the boom through 180° from its previous position in order to achieve water emission from the new cutting sector of the cutting head now within the cut. Conveniently, power to the transmission is provided by a prime mover e.g. an electric or hydraulic motor, carried by the non-rotatable part of the boom. Preferably, such prime mover comprises an electric motor located within the non-rotatable part of the boom, and having an axis of rotation coincident with the longitudinal axis of the non-rotatable part. Preferably, speed reduction gearing is incorporated within the boom. Such gearing may take the form of an epicyclic reduction stage. If further speed reduction is required, then the output of a first epicyclic reduction stage may be directed to a second epicyclic reduction stage. With any arrangement, the speed reduction gearing is preferably located within the rotatable part of the boom. It is also preferred for the bearing means between the non-rotatable and rotatable parts of the boom to consist of a plain journal bearing, and preferably two journal bearings that are axially spaced apart. Although in theory any convenient power means may be employed to achieve rotation of the rotatable part of the boom, preferably a worm and wheel arrangement is employed. In detail, the arrangement may comprise a worm drivable by an hydraulic motor. Preferably, two parallel, spaced­ apart worms in drivable mesh with a common wheel are employed, to engage the wheel at two 180° spaced locations. A shaft of the hydraulic motor(s) may project outwardly, so as to indicate the boom position. Re-positioning of the rotatable part of the boom, to result in sector selection variations, to suit positional variations of the boom and hence the cutting head, may be controlled by any of several alternative procedures. Thus, in its simplest form, rotation may be controlled manually by activation of hand controls by the machine operator, provided the machine operator has sight of the cutting head and/or the boom. Alternatively, automatic rotational control may be effected by attaching transducers to the boom (to register directionally, load or stresses within the boom) and/or the cutting head and/or the cutting picks and/or the conventional hydraulic control circuitry of the boom (to register flow and/or pressure changes) to sense the sector of the cutting head that is effecting cutting, the transducers being connected to electrical and/or hydraulic control circuitry to instigate rotation. In detail, the transducers may be of a pressure sensing kind and/or a movement sensing kind. As a further alternative, the boom may be provided with a trailing arm or a link mechanism in contact with the cut, to sense the location of the cut and hence the sector of the cutting head that is effecting cutting, with rotation, to achieve its desired re-positioning, being controlled through suitable control circuitry by movements of the arm or link mechanism. Finally, if the machine is of a kind provided with a micro-processor which retains a profile cutting pattern program, then this program may be modified to control additionally positioning, as the sector in the cut is pre­ determined. Conveniently, water from a pressure supply source (e.g. at 100 - 1,000 p.s.i. or higher), is conveyed along a supply conduit drilled along the longitudinal axis of the drive shaft, the supply conduit terminating at a distribution block within the cutting head and being intersected by a plurality of radiating supply conduits and associated non-­ return valves and serving both the pistons and the nozzles or group of nozzles. The invention will now be described in greater detail by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a side elevation of a roadheader type mining machine; Figure 2 is a plan view of Figure 1; Figure 3 is a perspective view of the end of the boom of the machine of Figures 1 and 2, remote from the machine; Figure 4 is a diagrammatic, axial sectional view along the boom of Figure 3; Figure 5 is a section on the line V-V of Figure 4; and Figure 6 is an axial sectional view to an enlarged scale along the boom of Figures 3 to 5. In the drawings, a roadheader type mining machine 1 is shown seated on a mine floor 2 over which the machine is manoueverable on crawler tracks 3 under the control of a machine operator, an operator's seat being indicated at 4 and a bank of control valves at 5. The machine 1 comprises a chassis 6 provided with a spoil gathering/loading conveyor 7 and carrying one, end 8 of an elongate boom 9 having a longitudinal axis 10, the boom 9 being mounted on a turn-table arrangement 11 for swinging movements about a vertical axis, and on pivot pins 12 for swinging movements about a horizontal axis, such movements being powered in the known manner by hydraulic rams 13 under operator's control via the valves 5. At its other end 14 the boom 9 is provided with a cutting head 15 rotatable about the boom axis 10 and provided with a plurality of cutter picks releasably retained in pick boxes 16 and associated water spray nozzles 17 to emit a water spray or jet, (Figure 3). The chassis 6 also carries a power unit in the form of an electric motor (not shown) to power a hydraulic pump(s) (not shown) for various hydraulic functions of the machine 1, including drive to the tracks 3. As best seen in Figures 3 and 4, the boom 9 is of a two-part construction comprising one part 18 that is non-rotatable about the boom longitudinal axis 10, which part 18 carries towards its outer end bearing means in the form of two axially spaced-apart journal bearings 19 for rotatably supporting another, part 20 that is rotatable with respect to the inner part 18 about the boom longitudinal axis 10 by a power means 21, in the form of an electric motor having an axis of rotation co-incident with the boom axis 10 and carried by the non-rotatable part 18. A transmission 22 extends from the power means 21 to the cutting head 15, and as detailed in Figure 6 comprises a final drive shaft 23 located at least partially within the rotatable part 20, co-axial with the boom longitudinal axis 10, and projecting therefrom, having a splined terminal end 24 on which is mounted a correspondingly splined mounting ring 25 to which the head 10 is secured by bolts 26. The transmission 22 also comprises a first epicyclic reduction stage 27 comprising an input shaft 28, a sun wheel 29, planet wheels 30, an annulus 31 and a carrier shaft 32, the latter having a sun wheel 33 of a second epicyclic reduction stage 34, which also includes planet wheels 35, an annulus 36 and a carrier 37 formed integrally with an end 38 of the final drive shaft 23 remote from the cutting head 10. The final drive shaft 23 is also provided with pumping means 39 to intensify a low pressure water supply to a high pressure water supply to be emitted by the nozzles 17. In detail, the pumping means 39 comprises two banks 40, 41 of multiple radial pistons 42, each reciprocally located in one radially extending cylinder 43 having a closed inner end 44 and an open outer end 45, with a variable volume, pressure-generating chamber 46 defined between a radially inner end 47 of each piston 42 and the closed, inner end 44 of its cylinder 43. A radially outer end 48 of each piston 42 is in direct or indirect permanent contact with an inner profile 49 of a bearing ring 50 carried by the rotatable part 20 and located eccentrically with respect to the boom axis 10, such that upon rotation of the drive shaft 23, variations in radial distance of the inner profile 49 from the axis 10 cause reciprocation of each piston 42, and a consequent pumping effect. Low pressure water is supplied to the pumping means 39 from a remote pump (not shown) along a supply bore 51 co-axial with the boom axis 10 and passing through the input shaft 28, carrier shaft 32 and final drive shaft 23 into a distribution block 52 in a fluid flow connection with transfer ports 53, each with a non-return valve 54, extending axially and then radially along the final drive shaft 23 to each pressure generating chamber 46, with, upon the pressure stroke, water being returned along the transfer ports 53 but because of the presence of the valves 54 being directed into radiating supply conduits 55 and then via piping 56 (Figure 4) to the nozzles 17 or groups of nozzles 17. Phased supply to the nozzles 17, to achieve water emission over only a prescribed sector of the cutting head 15, is controlled by suitable angular rotation and re­ positioning, between selected static positions, of the rotatable part 20 with respect to the non-rotatable part 18 about the longitudinal axis 10 of the boom to cause consequent rotation of the bearing rings 50, and such rotation is achieved by a power means in the form of worm and wheel arrangement 57 comprising upper and lower worms 58 rotatable about parallel axes by hydraulic motors 59, the worms being in drivable mesh with a common wheel 60 at two 180° spaced locations. In its simplest form, rotational re­ positioning of the rotatable part 20 may be controlled manually by activation of hand controls such as valves 5 by the machine operator.

Claims: 1. A roadheader type mining machine (1) comprising a self-propelled chassis (6), an elongate boom (9) having a longitudinal axis (10), the boom (9) being supported by the chassis (6) for powered positional adjustment with respect to the chassis (6), a terminal end (14) of the boom (9) provided with a rotary cutting head (15) drivable by a transmission (22), including a final drive shaft (23), co-axial with the boom longitudinal axis (10), the cutting head (15) having a plurality of nozzles (17) each to emit a water spray or jet, with water supplied to the nozzles (17) along conveying conduits (51, 53, 55), characterised in that the boom (9) is of a two-part construction comprising one part (18) that is non-rotatable about the boom longitudinal axis (10), that is supported from one end (8) on the chassis (6), and that carries towards its other end (14) bearing means (19) for rotatably supporting another part (20), and power means (59) carried by the non-rotatable part (18) to rotate the rotatable part (20) about the boom longitudinal axis; the final drive shaft (23) being located at least partially within the rotatable part (20), and provided with at least one radially extending cylinder (43) having a closed inner end (44) and an open outer end (45), the or each cylinder (43) at least partially housing a piston (42) which is reciprocable within its cylinder (43), with a variable volume, pressure-generating chamber (46) defined between a radially inner end (47) of the piston (42) and a closed, inner end (44) of its cylinder (43), and with the radially outer end (48) of the or each piston (42) being in direct or indirect contact with an inner profile (49) of a bearing ring (50) carried by the rotatable part (20) eccentrically with respect to the boom longitudinal axis (10), such that upon rotatation of the drive shaft (23), variations in radial distance of the inner profile (49) from the axis (10) cause reciprocation of the or each piston (42), and a consequent pumping effect, and with phased supply to the nozzles (17) being controlled by suitable angular rotation of the rotatable part (20) about the boom longitudinal axis (10) to cause consequent rotation of the ring (50). 2. A machine as claimed in Claim 1, wherein power to the transmission (22) is provided by a prime mover carried by the non-­ rotatable part (18) of the boom (9). 3. A machine as claimed in Claim 2, wherein the prime mover comprises an electric motor (21) located within the non-rotatable part (18) of the boom (9), and having an axis of rotation coincident with the boom longitudinal axis (10). 4. A machine as claimed in any one of Claims 1 to 3, wherein speed reduction gearing (29) is incorporated within the boom (9) comprising a first epicyclic reduction stage the output of which is directed as an input to a second epicyclic reduction stage. 5. A machine as claimed in Claim 4, wherein the speed reduction gearing (29) is located within the rotatable part (20) of the boom (9). 6. A machine as claimed in any one of Claims 1 to 5 wherein the bearing means (19) between the non-rotatable and rotatable parts (18, 20) of the boom (9) comprises two journal bearings (19) that are axially spaced apart. 7. A machine as claimed in any one of Claims 1 to 6, wherein a worm and wheel arrangement (57) is employed to achieve rotation of the rotatable part (20) of the boom (9) comprising two parallel, spaced-apart worms (58) in drivable mesh with a common wheel (60) to engage the wheel (60) at two 180° spaced locations. 8. A machine as claimed in any one of Claims 1 to 7 comprising hand controls (5) for repositioning of the rotatable part (20) of the boom (9), to result in sector selection variations. 9. A machine as claimed in any one of Claims 1 to 9, wherein automatic rotational control for repositioning of the rotatable part (20) of the boom (9), to result in sector selection variations, is effected by attaching transducers to the boom (9) (to register directionally, load or stresses within the boom) and/or the cutting head (15) and/or the cutting picks and/or the conventional hydraulic control circuitry of the boom (9) (to register flow and/or pressure changes) to sense the sector of the cutting head (15) that is effecting cutting, the transducers being connected to electrical and/or hydraulic control circuitry to instigate rotation. 10. A machine as claimed in any one of Claims 1 to 9, wherein the boom (9) is provided with a trailing arm or a link mechanism in contact with the cut, to sense the location of the cut and hence the sector of the cutting head (15) that is effecting cutting, with rotation, to achieve its desired re-positioning, being controlled through suitable control circuitry by movements of the arm or link mechanism. 11. A machine as claimed in any one of Claims 1 to 10, wherein water from a pressure supply source is conveyed along a supply conduit (51) drilled along the longitudinal axis of the drive shaft (23), the supply conduit (51) terminating at a distribution block (52) within the cutting head (15) and being intersected by a plurality of radiating supply conduits (55).

Inventors: PARROTT, GEORGE ALBERT
Applicants: DOSCO OVERSEAS ENGINEERING LIMITED
Application year: 1986
Main classification: E21D9
IPC codes: E21D9, E21C35