GB2042024A - Underground mining equipment - Google Patents

Abstract

A sensor means (21) for mounting on a mining machine to determine the height of a mine roof (3) is provided with wiper means (36) arranged to traverse from a position clear of the sensor means along a path adjacent to the sensor means to clear away broken mineral or rock, and control means including a sequence control unit for ensuring the machine is controlled in accordance with signals derived only when the wiper means is clear of the sensor means. <IMAGE>

Description

SPECIFICATION Underground mining equipment This invention relates to underground mining equipment for use in sensing at least one desired operational condition of mining machines within mineral or rock seams; to sensor equipment for sensing the desired operational condition; and to mining machines including such equipment.

In particular, although not exclusively, the present invention relates to mining equipment for use with sensors for sensing the distance of a cutter provided on a mining machine from a rock or mineral seam boundary, for example a mine roof or mine floor.

In the past, mechanical devices have been used to sense the distance of the cutter from the mine roof. Such mechanical devices require arms resiliently biassed towards the mine roof which, unfortunately, tend to becorne damaged as the machine traverses along the mine working face. Consequently, such prior known mechanical devices tend to have short useful operational lives.

An object of the present invention is to provide improved underground mining equipment which tends to overcome the above mentioned problem.

Accordingly, the present invention provides underground mining equipment for use with a mining machine including sensor equipment for sensing a desired condition which, in use, exists in the vicinity of the mining machine and for deriving a signal indicative of that sensed condition, the signal being fed to a control enabling the machine to be controlled in accordance with the sensed condition, the mining equipment comprising wiper means arrangeable in use, to traverse from a position clear of the sensor means along a path adjacent to the sensor means to clear away broken mineral or rock, and control means including a sequence control unit for ensuring that, in use, the machine is controlled in accordance with the signal derived only when the wiper means is clear of the sensor means.

Preferably, the mining equipment comprises a slide component slideably mounted with respect to a housing for the sensor equipment.

Conveniently, the slide component is slid along a slideway on the housing by hydraulic ram means.

Advantageously, the housing is provided with at least one wear resistant pad for contacting the slide component.

Preferably, the wiper means comprises at least one resiliently biassed wiper mounted on the slide component such that in use when sensor equipment is mounted in the housing the or each wiper is urged to slideably contact the sensor equipment.

Conveniently, the slide component provides a guard for protecting the sensor equipment.

The present invention also provides sensor equipment for a mining machine comprising sensor means for sensing a desired condition which, in use, exists in the vicinity of the mining machine and for deriving a signal indicative of that sensed condition, wiper means arrangeable to traverse from a position clear of the sensor means along a path adjacent to the sensor means to clear away broken mineral or rock, and control means for enabling the machine to be controlled in accordance with the sensed condition, the control means including a sequence control unit for ensuring that, in use, the machine is controlled in accordance with the signal derived only when the wiper means is clear of the sensor means.

Preferably, the sensor equipment comprises a housing having a sensing deck providing a window through which the condition can be sensed, the wiper means being arranged to pass over the window during its traverse.

Conveniently, the sensor equipment housing provides a slideway along which a slide component slides, the wiper means being mounted on the slide component.

Advantageously, the wiper means comprises at least one resiliently biassed wiper urged into contact with the window.

Preferably, the deck comprises at least one wear resistant pad arranged adjacent to the window.

Conveniently, the sensor means comprising an ultra sonic device for detecting the distance of the sensor equipment from a preselected boundary.

Alternatively, the sensor means comprising a radar device for detecting the distance of the sensor equipment from a pre-selected boundary.

Preferably, the control means senses when the signal reaches a preselected level indicative of the wiper means being in a position clear of the sensor means.

Alternatively, the sensor equipment comprises switch means arranged to sense when the wiper means are in a position clear of the sensor means.

The present invention also provides a mining machine in combination with equipment as defined above.

By way of example only, one embodiment of the present invention will be described with reference to the accompanying drawings, in which Figure 1 is a side view of equipment constructed in, accordance with the present invention mounted ori a ranging arm of an underground mining machine; Figure 2 is a plan of a part of the equipment of Fig. 1; Figure 3 is an end view of a part of the equipment of Fig. 1; Figure 4 is a scrap view of a detail of Fig.

1, looking in the direction of arrow IV in Fig.

1; Figure 5 is a side view of a detail of Fig. 1; Figure 6 is a plan of the detail of Fig. 5; Figure 7 is an end view of the detail of Fig.

5: Figure 8 is an incomplete sectional view along tine VIII-VIII of Fig. 5; Figure 9 is an incomplete sectional view along line tX-IX of Fig. 6; Figure 10 is an incomplete sectional view along line X-X of Fig. 6: Figure II is a electro-hydraulic block diagram of the control and activating circuits of the equipment of Fig. 1; Figure 12 is a part sectional view of a further detail of Fig. 1; and Figure 13 is an incomplete sectional view of an alternative construction of the further detail of Fig. 12.

Referring to Figs. 1 to 10 of the drawings, underground mining equipment 1 for use in sensing the distance from the current position of the rotary axis 2 of a rotary rock or mineral cutter (not shown) to the mine roof boundary 3 formed by the cutter on a previous traverse of a mining machine carrying the cutter along a longwall working mineral or rock face. The cutter is carried on a ranging arm 4 pivotally mounted on the mining machine body (not shown) moveable along a path defined by an armoured face conveyor extending along the longwall face. The arm 4 is raised or lowered about its pivotal axis under the action of a hydraulic ram (not shown) to vary the height of the mine roof currently being formed by the cutter relative to the machine body.

The underground mining equipment comprises a mounting frame 5 releasably attached to an upward facing surface 6 of the arm 4 by means of a fork arrangement 8 on the frame which is slid upwards into fixed engagement with an inclined key 9 provided on the arm.

The mounting frame is retained in fixed engagement with the key by a screw mechanism 10 having an adjustable plunger 11 for abutment with an upwardly extending flange 12 of the mounting frame. The base of the mounting frame is provided with a bridge piece 14 for bridging over a manifold 1 5 and pipe fitting 1 6 provided on the arm for supplying dust suppression fluid to a feed arrangement 16 feeding fluid along a shaft (not shown) drivably supporting the cutter for rotation about the previously mentioned axis 2.

The shaft is driven by gearing (not shown) extending within the arm.

The mounting frame 5 is provided with an upper support platform 20 upon which is mounted sensor equipment 21 for sensing the distance of the mine roof 3 from the equipment. The sensor equipment comprises a protective housing 22 which is secured to the platform 20 by bolts 24 and within which is located sensor means comprising an ultra sonic distance detecting device (as shown in Fig. 12) described later in this specification.

Alternatively, the sensor means may comprise a radar distance detecting device.

The housing is capped by two parallel wear resistant pads 25 arranged on either side of a window 26 provided in the upper deck of the housing and through which the sensor means senses the distance to the mine roof 3.

The side walls 27 and 28 of the mounting frame 5 are provided with two opposed groves 29 and 30 which slideably support two runners 31 and 32 fixedly secured by bolts 33 to side walls 34 and 35 of a protective hood 36 constituting a slide component. The top 37 of the hood 36 is provided with wiper means comprising two wiper assemblies 38 and 40 each comprising two similar outer or side wipers 41 associated with the wear resistant pads 25 and a central wiper 43 projecting in the gap between the two wear resistant pads 25 to slideably contact the window 26 of the sensor means. Each wiper 41 is accommodatedSin a stepped recess 42 and comprisses a resilient pad 45 urging a stepped wiper blade 46 towards the associated wear resistant pad 25. Each central wiper 43 comprises a stepper wiper housing 47 containing a resilient pad 48 and a stepped wiper blade 49.The wiper means are retained in position by locking caps 50 secured by bolts 51 on the top of the slide component. Thus in use, as the slide component 36 is slid to and fro along the slideway groves 29 and 30 the top of the housing and particularly the window 26 is cleaned of broken rock of mineral providing the sensor means with an unrestricted view of the mine roof 3. An inclined platform 52 is secured by bolts 53 to the arm 4, the platform guiding the flow of material away from the sensor means. Side cleaning strips 54 are bolted to the side walls of the slide component to help prevent broken rock or mineral.

The slide component 36 is moved to and fro under the action of a hydraulic ram 55 secured to the base of the support platform 20 by a pivotal mounting 56 and to an end wall 57 of the slide component 36, the end wall 57 being secured to the side walls 34 and 35 of the slide component by bolts 58.

Pressure fuid is fed to and from the ram 55 via lines 59 and 60 which pass down the mounting frame 5 and beneath a removable protective guard 62 secured to the arm 4 by bolts 63. An electrical cable 64 also accommodated beneath the guard 62 conveys an electrical signal derived by the sensor means and indicative of the sensed distance to the mine roof 3, the cable 64 comprising an outer protective shield which is attached to a anchorage 65 slotted in a forked support plate 66 and retained in position by a retaining plate 67 fixedly secured to the guard 62 by bolts 68.

Signal transmitting wires (not shown) housed with the protective cable 64 extend from the anchorage 65 to a connector 70 provided on the sensor means housing 22.

The associated electrical and hydraulic circuits are illustrated in Fig. 11. In Fig. 11 the feed lines 59 and 60 for the ram 55 are shown to extend from a pilot operated spring biassed control valve 75 arranged to feed pressure fluid alternatively along line 59 or 60 dependent upon the desired operation of the ram. Pressure fluid is fed to the valve 75 from a pump (not shown) along line 76 and return pressure fluid is returned to tank 78 via line 79.

Pilot operation of the valve 75 is controlled via pilot line 80 including a mode selection switch 81 from a sequence control unit 82 including a timer which feeds a pilot signal along line 80 to move the valve 75 against its spring loading for at a preselected frequency and for a preselected period of time. This operation determines for what proportion of the time the slide component is clear of the sensor means and for what proportion of the time the slide component is covering the sensor means. In Fig. 11 the sensor means is indicated at 90 and the slide component is indicated by 36 in a position covering the sensor means and by 36' in a position clear of the sensor means. Other items of the equipment have the same reference numbers as previously given with reference to Figs. 1 to 10.

Typically, the pilot signal energises the pilot of valve 75 such that the slide component is in a position clear of the sensor means 90 for one second at an interval of every three seconds. However, the setting of the sequence control unit is adjustable to vary the frequency and times to any desired level.

The derived electrical signal is fed from the sensor means 90 of the sensor equipment 21 to control means 92 which controls the vertical steering of the cutter in accordance with the signal and which includes a unit 93 enabling the control means 92 to ignore the received signal when it falls to a level indicative that the side component is not clear of the sensor means. Alternatively, the acceptance of the received signal by the control means may depend upon the actuation of a switch mechanism 95 arranged to sense when the slide component is clear of the sensor means. As a further alternative the control means may accept and act on the received signal only when instructed by the sequence control unit 82.

The signal derived when the slide component 36 is clear of the sensor means is used by the control to vertically steer the cutter during its present cut, the signal enabling the machine control to determine the height of the cutter on the present cut relative to the previously sensed cut and thereby determine any necessary vertical correction which may be needed on the present cut. Vertical adjustment of the cutter height is made by pivoting the arm 4 about its pivotal mounting.

The sensor equipment 21 is shown in detail in Fig. 1 2 and comprises the previously mentioned protective housing 22 securable by bolt 24 to the mounting frame platform 20 (not shown in Fig. 12). The protective housing has a removable base 100 secured to the rest of the housing by bolts 101 which are not accessible when the housing is located on the platform. The acoustic sensor means 90 provided within the housing comprises an acoustic transmit transducer 103 (shown in section), an acoustic receiver transducer 104 and a signal proclessing unit 105. The transmit and receiver transducer are of similar construction, each comprising a generally cupshaped formation 106 providing a central cylindrical element 107 supported midway along its length by the stepped side of the cup shaped formation.The axial length of the cylindrical element is substantially equal to one wave length of the transmitted wave.

Thus the mid way location of the support provided by the side of the formation 106 corresponds to a mode point and thereby does not significantly interfere with the passing wave. The ends of the cylindrical elements 107 are arranged in the windows 26 in the upper deck of the housing 22.

The piezo electric element 110 secured to each cylindrical element by a bolt 111 comprises a piezoelectric crystal arrangement 11 2 typically including four crystals arranged at ninety degree intervals around the bolt 111.

The crystal arrangement 11 2 is sandwiched between two vibrating masses 11 4 and 11 5.

The bolt 111 also secures two electrical connector tags 11 6 and 11 7 in position on opposite sides of an insulating block 11 8.

Each cup shaped formation 106 is resiliently supported in the housing by a cylindrical seal 1 20 provided around a part of the cylindrical element 107 and by two ring seals 121 and 122 located between steps in the formation side and adjacent parts of the housing. These seals are provided to ensure that the transducers 103 and 104 are acoustically insulated from one another other than by means of the transmitted wave as described later in the specification.

Electrical signals are fed from the tags 11 6 and 11 7 to an electrical circuit block 1 30 which in turn is electrically connected to the signal processing unit 105 by lines (not shown) connected to connectors 1 31. The block 1 30 is housed with a cap 1 32 of the transducer which is bolted to the formation 106 by bolts 1 33 in a manner to provide a flameproof gap between the cup and the formation ie a flame cannot be transmitted through the gap.

In use, the transmit and receiver transduc ers are positioned substantially perpendicular to the mine roof 3 and operated in a pulse echo mode, ie a pulse of sound energy at an appropriate frequency is repeatedly transmitted by the transmit transducer towards the mine roof and the return echo detected by the receiver transducer. The length of time taken for this excursion is directly related to the distance travelled and depends upon the distance of the mine roof from the sensor means.

The signal processor unit 105 instructs the transmit transducer to transmit by modulation of the electrical supply to the transducer. A high voltage of several hundred volts is generated inside the transmit transducer and applied to the piezoelectric crystals which thereby transmit the desired wave pulses. The electrical block in the receiver transducer houses an amplifier and the received output is fed back to the signal processor unit and compared in time with the transmit signal and an indicative signal derived which is then fed to the control means via electrical connector 70 enabling the mining machine to be vertically steered in accordance with the sensed distance.

Fig. 1 3 shows an alternative sensor equipment 21 comprising a radar distance sensing device comprising a parabolic reflector 140 and an antenna arrangement 141 including a microwave integrated circuit 142 and a launcher 143 comprising a transmit transducer and a receiver transducer. Electrical wiring to the micro integrated circuit is encased in tubing 144. Support frame work for the antenna is shown at 145.

In operation, the mining machine traverses to and fro along the armoured flexible conveyor adjacent to the working rock or mineral face. The machine is vertically steered to remain within the rock or mineral seam. The distance from the mine roof from the previous cut to the sensor equipment 21 is determined by the transmit transducer of the launcher 143 transmitting an electromagnetic microwave signal via the reflector 140 to the mine roof and receiving the reflected signal via the reflector 140 at the receiver transducer of the launcher 143. It is to be understood that the microwave signal is transmitted and received in an analogous manner. The microwave carrier signal is frequency modulated at a frequency fm by the circuitry as will be described later in the specification.

The reflected signal from the mine roof differs in frequency from the transmitted signal owing to frequency shift produced by the modulating frequency frn during the transit time of the signal. The difference in frequency of the transmitted and received signal, f1, is a measure of roof height.

Roof height R is given by the following equation: fj.c 4/\f fm where c is the velocity of light and tf is the frequency deviation, ie difference between maximum and minimum frequency transmitted by the transmitter.

Since the mine roof height is such a small length, only of the order of a half meter it is not possible to use variation of fj or fm to determine roof height because fj and fm are relatively close in a frequency spectrum and it is difficult to vary either frequency without overlapping the other frequency or harmonics.

Consequently, in order to determine roof height Af is modulated.

The microwave frequency is arranged to rise and fall linearly with time and thus considering a situation when the roof height distance is fixed, the fj pockets occuring between phase changes are monochromatic.

From the above description it will be seen that the present invention provides underground mining equipment for use in sensing at least one desired operational condition of mining machines within mineral or rock seams, for example, the height of the mine roof from the machine body, which is robust, reliable and capable of giving accurate results.

The present invention also provides improved sensor equipment for sensing the desired operational condition.

Further, the present invention provides a mining machine comprising improved sensor equipment.

Claims (18)

1. Underground mining equipment for use with a mining machine including sensor equipment for sensing a desired condition which, in use, exists in the vicinity of the mining machine and for deriving a signal indicative of that sensed condition, the signal being fed to a control enabling the machine to be controlled in accordance with the sensed condition, the mining equipment comprising wiper means arrangeable, in use, to traverse from a position clear of the sensor means along a path adjacent to the sensor means to clear away broken mineral or rock, and control means including a sequence control unit for ensuring that, in use, the machine is controlled in accordance with the signal derived only when the wiper means is clear of the sensor means.

2. Equipment as claimed in claim 1, comprising a slide component slideably mounted with respect to a housing for the sensor equipment.

3. Equipment as claimed in claim 2, in which the slide component is slid along a slideway on the housing by hydraulic ram means.

4. Equipment as claimed in claim 2 or 3, in which the housing is provided with at least one wear resistant pad for contacting the slide component.

5. Equipment as claimed in claim 2, 3 or 4, in which the wiper means comprises at least one resiliently biassed wiper mounted on the slide component such that in use when sensor equipment is mounted in the housing the or each wiper is urged to slideably contact the sensor equipment.

6. Equipment as claimed in any one of the preceding claims 2 to 5, in which the slide component provides a guard for protecting the sensor equipment.

7. Sensor equipment for a mining machine, comprising sensor means for sensing a desired condition which, in use, exists in the vicinity of the mining machine and for deriving a signal indicative of that sensed condition, wiper means arrangeable to traverse from a position clear of the sensor means along a path adjacent to the sensor means to clear away broken mineral or rock, and control means for enabling the machine to be controlled in accordance with the sensed condition, the control means including a sequence control unit for ensuring that, in use, the machine is controlled in accordance with the signal derived only when the wiper means is clear of the sensor means.

8. Equipment as claimed in claim 7, comprising a housing having a sensing deck providing a window through which the condition can be sensed, the wiper means being arranged to pass over the window during its traverse.

9. Equipment as claimed in claim 8, in which the sensor equipment housing provides a slideway along which a slide component slides, the wiper means being mounted on the slide component.

1 0. Equipment as claimed in claim 8 or 9 in which the wiper means comprises at least one resiliently biassed wiper urged into contact with the window.

11. Equipment as claimed in claim 8, 9, or 10, in which the deck comprises at least one wear resistant pad arranged adjacent to the window.

1 2. Equipment as claimed in any one of the preceding claims 7 to 11, in which the sensor means comprising an ultra sonic device for detecting the distance of the sensor equip ment from a preselected boundary.

1 3. Equipment as claimed in any one of the preceding claims 7 to 11, in which the sensor means comprising a radar device for detecting the distance of the sensor equipment from a preselected boundary.

1 4. Equipment as claimed in any one of thesreceding claims 7 to 13, in which the control means senses when the signal reaches a preselected level indicative of the wiper means being in a position clear of the sensor means.

1 5. Equipment as claimed in any one of the preceding claims 7 to 13, in which the sensor equipment comprises switch means arranged to sense when the wiper means are in a position clear of the sensor means.

16. An underground mining machine in combination with equipment as claimed in any one of the preceding claims.

1 7. Underground mining equipment for use with a mining machine, substantially as described with reference to the accompanying drawings.

18. Sensor equipment for a mining machine, substantially as described with reference to Figs. 1 to 12, or to Fig. 1 3 of the accompanying drawings.

1 9. A mining machine substantially as described with reference to the accompanying drawings.