DE2251813A1 - EXTRACTION MACHINE FOR STRIP EXTRACTIONS - Google Patents

Description

51813

Patent attorney

Karl A. Brose

Dipl.-Ing.
D- 8C23 Munich Püllach

from left / Pz Munich-Pullach, October 19, 1972

Case 3248

COAL INDUSTRY (PATENTS) LIMITED, Hobart House, Grosvenor

Place, London SW1X 7AE, England

Extraction machine for longwall mining operations

The invention relates to a mining machine for longwall mining operations. In particular, the invention relates to a mining machine for longwall mining with a probe - which can respond to the position or location of the machine in the seam.

It is known in the art to include a radiation emitter and a radiation emitter in such an extraction machine Detector probe combined to use, which are mounted on an arm protruding from the extraction machine, whereby this arm to a point near the hanging layer boundary of the seam which is cut by the cutting head of the machine. Since it is not possible in practice If the probe is to be placed in the current cutting zone or mining zone, it must be at some distance from the cutting head to be brought. If the probe is mounted behind the cutting head, it cannot scan the cutting zone immediately, which is continuously cut, but time must be allowed for the machine to advance along its path is. If the cutting zone or cutting horizon of the cutting head is changed relative to the seam, what

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is the case, for example, when a conveyor trough, which forms the path of the machine in a known manner, is inclined relative to the lying position, the probe according to the known embodiment cannot detect this change until the machine has advanced sufficiently so that the probe reaches the point where the horizontal change in position took place. After the well has reached this point, the signals derived from the well controls the control mechanism of the mining machine in order to introduce a correction in the horizontal cutting position or mining position. At this point in time, however, the mining horizon may have deviated even further from the desired path within the seam. On the other hand, there is also the possibility that at the time when the change in the mining horizon was determined by the probe, the cutting head had already been moved back into the desired path , so that when the intended correction finally reached the control mechanism, the cutting head would then move out of the desired path will. The result is that the cutting head swings around the desired path and repeatedly cuts into the rock layer near the hanging wall and near the lying of the seam.

After the coal layer has been extracted and the conveyor troughs are moved against the freshly broken impact, so follow they the corrugations that have been cut by the cutting head so that when the mining machine moves along moves the troughs, this effect is accumulative and thus the Corrugations in the cutting horizon appear more pronounced and can ultimately cause the extraction machine must be controlled by hand until a new cutting horizon is formed.

An object of the present invention is directed to

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Creation of a mining machine for longwall mining operations, the changes in the cutting horizon or in the cutting zone of the machine cutting head are essentially detected when these appear.

According to a feature of the present invention, the mining machine for longwall mining has at least one cutting head on, further a support arm that can be attached to that part of the machine which carries the cutting head, so that the arm is moved along with this part of the machine, the machine has a further arm which is supported by said support arm and which carries a probe to to scan the position of the rock boundary of the seam, the arm being supported so that the probe against this during operation Limit is pressed and means are provided to the Displacement of the probe relative to its attachment point or to the holding arm or to sense it.

In an advantageous way you can change the length of the arm, the arm then comprising a hydraulic bumper.

According to another embodiment, the arm can also be stiff, in which case the support ode.r mounting arm and the probe are resilient pushes against the said limit.

The means mentioned consist of a preferred catfish • linear potentiometer. However, these means can also consist of a rotary potentiometer.

According to a further feature of the present invention the previously described facility is provided in combination with the longwall mining machine.

The machine advantageously has a rotary cutting

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head and guide means »to attack a train or rail, on which the machine moves, the guide means are arranged directly below the axis of rotation of the cutting head.

Further advantages and details of the invention emerge from the description of exemplary embodiments which now follows referring to the drawing. It shows!

Fig. 1 is a schematic side view of a mining machine for longwall mining, this Machine is equipped with a first embodiment of a control device for the machine, having the features of the present invention;

Flg. FIG. 2 is a schematic plan view of the machine according to FIG Fig. 1;

Fig. 3 is an electrical circuit diagram for said device;

Fig. 4 is a schematic side view of a mining machine for longwall mining, with a second embodiment of the control unit for controlling the Machine constructed in accordance with the present invention; and

FIG. 5 is a schematic end view of the machine of FIG.

Figures 1 and 2 illustrate a mining machine 1 for longwall mining operations and this machine moves along of a coal face 2 along a path that has a series

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is formed by conveyor troughs or pans 3. The machine has a lower frame 4 and guide means 5 (only one only one of these is illustrated), which attack the upper flanges of the conveyor troughs 3 in a known manner. if if the machine moves along the joint 2, a rotatable cutting head 6 with cutting tools (not shown) wins from this layer of coal, which is then loaded onto the conveyor with the help of a loading hood (not shown) that is located behind the Cutting head 6 is arranged. The hanging wall of the coal strip, which is cut by the cutting head is denoted by 7, and the lying surface of the coal seam is denoted by 8. The guides 5 at the end of the machine, near the cutting head, are located directly below the axis of the cutting head.

A combined beam emitter and detector probe 10 is mounted on one end of an arm 11 which has an upwardly pointing hydraulic piston and which is fixed on a support mounting arm 12 is arranged, which in turn is attached to the lower frame 4 of the machine and is connected to this machine moved along. The probe 10 is cut by the arm against the hanging wall 7 of the seam strip which is cut by the cutting head 6 is pressed, and it scans the thickness of the coal layer 13, which is left by the cutting head 6 under a rock boundary 14. The probe 10 is an electrical Signal from which is typically 0.166 volts per inch thickness of the carbon layer and which to a control device (not shown in Figs. 1 and 2) which controls the control mechanism of the machine so that the thickness of the Carbon layer 13 is maintained within preselected limits, such as between 4 and 5 inches. If that's from the The signal emitted by probe 10 indicates that the coal layer is thick is outside these limits, the control mechanism actuates the control mechanism, which then sets the cutting position or horizontal cutting

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position of the cutting head readjusts until the thickness of the carbon layer is again within the stated limits.

The control mechanism of the machine consists of hydraulic ones Plungers (not shown) connecting two pivotally connected parts of the lower frame 4; an actuation of these pistons by the control mechanism has a lifting or a lowering of the part of this lower frame on which the machine and the mounting arm 12 relative to the result other part, which is attached to the guides 5 1st, are supported.

Fig. 3 shows part of the electrical circuit of the control device for the machine and this control device is with the exception of the probe 10 and a linear potentiometer 20, which are arranged in the arm 11, in a control panel the machine 1 arranged.

The linear potentiometer 20 is mounted in the office 11 so that upon movement of the piston of the hydraulic pressure piston device within the cylinder the contact or pointer 21 via the two resistors of the linear potentiometer 20 is deleted, with the output signal typically between 4-10 volts to 0-10 volts fluctuates, depending on the extent to which the hydraulic piston or pressure piston device is drawn out is dependent. The linear potentiometer 20 gives an output signal which is 0.166 volts per inch of displacement of the plunger.

In addition to the output signals from the probe 10 and the linear potentiometer 20, the control device can receive an output signal from an inclination meter 25, which is arranged on the machine 1, such that it determines the inclination of the machine relative to the mean inclination of the horizontal plane

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Seam detected in a direction perpendicular to joint 2. That The output signal of the inclination meter 25 is typical 1 volt per degree. The control device contains in the line from the inclination meter 25 a bridge network of diodes 26, which ensures that only output signals of the inclination meter 25 which are greater than -4.3 volts are received by the remaining switching sections of the control device can. This network creates the possibility that the machines i incline in a direction perpendicular to the joint can within a range of - 4.3 ° around the mean slope of the fall, with no corrective action whatsoever can be initiated by the control device.

The controller also receives an output from a variable resistor 28, which is typically between 0 and 10 volts can fluctuate. The resistor 28 is set by a person skilled in the art so that an output signal is emitted, which corresponds to a certain thickness of the coal layer 13 that is to be left below the rock boundary 14. The resistance 28 is normally blocked in the set position and is only readjusted if required is to change the thickness of the carbon layer 13.

The outputs of the probe 10, the linear potentiometer 20 and the variable resistor 28 become over 10,000 Ohin resistors each routed and the output signal of the Inclination meter 25 is conducted over a 1,000 ohm resistor. This ensures that when a signal from the inclinometer 25 is sufficiently large that it can pass through the Diode array 26 arrives, the effect of this signal on the control device is 10 times larger than the effects of the other output signals mentioned.

All four output signals, together with a feedback

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signal are passed through a 10,000 ohm resistor and then go to an inverting operational amplifier 30. In addition to amplifying the signals, the amplifier 30 effectively adds the four input signals algebraically (or five input signals if the signal from the inclination meter 25 is greater than ί 4.3 volts) and the amplifier 30 emits an output signal which indicates the required position of the pressure piston of the control mechanism to a desired cutting height or cutting horizon of the cutting head 6 reach.

This signal is then passed through a resistor of 10,000 ohms before it is fed to an operational amplifier 31 which reverses the sign and which operates as a comparison stage. The signal fed to amplifier 31, along with a feedback signal and an output signal from a Converter 32, which scans the actual position of the working pistons present in the control mechanism of the machine are passed through resistors of 10,000 ohms so that they have the same proportional effect on amplifier 31 to have.

The amplifier 31 effectively compares the actual position of the control mechanism with that desired or required Position which is indicated by the output signal from the amplifier 30 and derives an output signal which is indicative of the error in the position of the control mechanism. This output signal is provided by a "dead zone" circuit 33 which blocks the output signal if it falls within acceptable limits, in which case the existing cutting height of the cutting head is acceptable.

However, when the output from the amplifier 31 is outside is within acceptable limits, ao it will be through the "dead."

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Zone "circuit 33 is transmitted to a control circuit 34, the appropriate way actuates the control valves of the control working pistons until the cutting height or the cutting horizon of the cutting head 6 has reached an acceptable position or path.

In operation, so when the machine is working its way forward along the joint, the output signals from the probe 10, from the inclination meter 25 and the linear potentiometer 20 to the control device.

The signal from the probe 10 keeps the thickness of the carbon layer 13 within 4 to 5 inches. If the cutting height or the The cutting horizon of the cutting head 6 should change, or if the height or the course of the rock boundary 14 changes should change, the resultant change in the output signal of the probe 10 causes the control device appropriately adjusts the control mechanism of the machine.

When the machine is inclined and via in a direction perpendicular to the shock - so effected to correct 4.3 °, the output signal from the inclinometer 25, the control means sets again the control mechanism of the machine to its inclination. Since the output signal from the inclinometer is passed through a resistor that is ten times smaller than the 10,000 ohm resistors through which the other output signals are passed, the influence of this output signal is much more effective on the control device and this influence masks the influence of the other output signals.

The output signal from the linear potentiometer 20 shows the degree of extension of the hydraulic plunger or arm

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at. When the machine is initially applied to the shock, the linear potentiometer 20 is adjusted so that the Slider 21 comes to rest in the middle zero position and the variable resistor 28 is set so that an output signal is emitted which corresponds to the desired thickness of the carbon layer 13. If now the machine along the track, d. H. working along the joint 2, any change in the length of the arm leads to d. H. a vertical displacement of the probe 10 relative to the mounting arm 12 to a corresponding change in the output signal of the linear potentiometer 20.

Therefore, when the machine is when it operates along the thrust forward, comes to a sloping conveyor trough 3 as shown in Fig. 1, as the front portion of the machine is moved along the sloping path ¹ upward. However, since the cutting head 6 is located near the rear of the machine with its axis directly above the rear guides 5 about which the machine effectively pivots during the upward movement of the front part of the machine, the cutting height or horizon of the cutting head 6 remains essentially unchanged.

After the rear guides 5 the inclined Having reached trough 3 and starting to follow this inclination, the arm 11 is caused to contract, i. H. the piston of the associated pressure piston device is pressed further into the associated cylinder. The diminution the length of the plunger device is sensed by the linear potentiometer 20 as the wiper 21 moves along one of the resistors is moved. The change in the output signal from the potentiometer 20 causes the control device the cutting height of the cutting head 6 accordingly

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a — sets so that the hanging wall 7 »that through the cutting head 6 is provided, is kept running essentially parallel to the rock boundary 14 and the thickness of the coal layer 13 remains essentially constant. . ■

The dashed line 7 'indicates the hanging wall that goes through a machine is cut which is not equipped with a control device according to the present invention, so that the cutting height or the cutting horizon runs parallel to the path of the machine.

A similar process occurs when the machine is following a downward slope or when it passes over a Wave is moved in the path.

4 and 5 show a second embodiment of the device for controlling a mining machine for longwall mining operations. The machine is constructed similarly to that in the previous exemplary embodiment, so that in FIGS and 5 the same reference numerals are used for the same parts, which therefore also appear in FIGS. 1 and 2.

In the second embodiment, the probe 10 is arranged directly above the axis of rotation of the rotatable cutting head 6 and is pressed into contact with the hanging wall of the previously extracted coal strip, d. h, against the hanging that during of the previous cut of the machine. The probe 10 is arranged on an arm 11, the one after has protruding hydraulic piston-cylinder arrangement and which is fixedly mounted on a support arm 12 which is attached to the Machine 1 is provided.

When the machine now works its way along the joint, the conveyor 3 is lifted by the lying person 8, i.e. both

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for example, when the conveyor rises on a layer of fine coal that rests on the horizontal 8, so that a false horizontal 8 'is formed. The machine would then follow the conveyor and the cutting head 6 would cut into the hanging wall. The dashed line 7 'indicates the end of the hand that would have been cut if no tax correction had been made. However, as soon as the machine begins to climb, the arm 11 senses this movement relative to the hanging wall of the previous excavation and the control device is provided with a signal which may be similar to that described with reference to the first embodiment of the invention and which leads to a corresponding adjustment of the cutting height or the cutting horizon 'of the cutting head 6, so that the hanging wall 7 _t provided by the cutting head is kept running essentially parallel to the rock boundary 14 and the thickness of the coal layer 13 also remains essentially constant .

From the preceding description it can be seen that the present invention is a simple and effective Device for controlling a mining machine for longwall mining operations is created, which is faulty or undesired Changes in the cutting height of the machine or the cutting head of the machine scanned to one Timing when these occur and what is effective in minimizing or eliminating these changes.

In a modified embodiment according to the invention the mounting arm is attached to the machine such that the arm 11 is inclined.

In the other embodiments, the support arm or the Arm is mounted pivotably relative to the machine and it is then

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not a change in the extension of the arm measured, but a change in the inclination of the arm relative to the machine or measured to the seam.

All details which can be seen in the description and shown in the drawing are important for the invention.

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Claims (6)

PATENT CLAIMS 1. Extraction machine for longwall mining operations with a control device for controlling the mining machine, which has at least one cutting head, further a mounting arm, which on that part of the machine is attached which carries the cutting head, with another supported by the mounting arm Arm on which a probe is arranged in order to scan the position and the location of the rock boundary of a seam, the arm being held in such a way that, during operation, the probe is pressed against the boundary layer or hanging wall, thereby characterized in that the mounting arm (12) is arranged on said part (4) of the machine (1) and moves with it, and that means (20) are provided to sense the displacement of the probe (10) relative to the mounting arm. 2. Extraction machine according to claim 1, characterized in that the length of the arm (11) is variable and that the arm has a hydraulic piston-cylinder unit. 3. Extraction machine according to claim 1, characterized in that "the arm is made rigid and that the mounting arm The probe presses resiliently against the boundary layer or hanging wall. 4. Extraction machine according to one of the preceding claims, characterized in that the scanning means (20) consists of one Potentiometers exist. 5. Extraction machine for longwall mining operations, with one cutting head and a control device, further with a mounting arm which is attached to that part of the machine which the Carries cutting head, with another arm held by the mounting arm, on which a probe for scanning the position of the 3 0 9 Π 2 0/0 2 3 A Rock boundary of a seam is arranged, this arm is supported so that the probe against during operation the boundary surface or hanging wall is pressed, characterized in that the mounting arm (12) on the part (4) of the machine (1) is arranged for a common movement with this part and that means (20) are provided for the displacement the probe (10) relative to the mounting arm to be scanned. 6. Extraction machine according to claim 5, with eineta rotatable Cutting head and with guide means that engage a guide track or guide rail on which the machine works forward, characterized in that the guide means is directly below the axis of rotation of the cutting head are arranged. 309820/0 23