AU722290B2

AU722290B2 - Device for detecting the penetration depth of cutting tools

Info

Publication number: AU722290B2
Application number: AU33286/97A
Authority: AU
Inventors: Peter Kogler; Nikolaus A. Sifferlinger
Original assignee: Tamrock Voest Alpine Bergtechnik GmbH
Current assignee: Sandvik Mining and Construction GmbH
Priority date: 1996-07-18
Filing date: 1997-07-09
Publication date: 2000-07-27
Anticipated expiration: 2017-07-09
Also published as: EP0912816A1; DE59705784D1; ATE210782T1; AU3328697A; EP0912816B1; ATA129696A; WO1998003770A1; ES2134181T1; AT406892B

Abstract

In a cutting control process for kirving tools (6) on advance working machines (2), the depth of cut of the kirving tool (6) is detected and the measurement data for the depth of cut are linked to a control unit in which the geometry of the winning tool is stored and measurement data for load-bearing capacity are taken into account. To carry out the process a device is provided for detecting the depth of cut of kirving tools (6) of advance working machines (2) into the rock face, said device comprising in the forward region of the advance working machine (2) at least one proximity sensor (7) directed to the rock face and connected to an evaluation unit.

Description

i Device for Detecting the Penetration Depth of Cutting Tools The invention relates to a device for detecting the penetration depth of cutting tools of mining machines into the mine face.

Selective cut heading machines for excavating the mine face initially require penetration into the mine face. To this end, the selective cut heading machine is displaced in a manner that the excavation tools penetrate into the mine face over a predetermined penetration depth, whereupon cutting off of the total mine face surface is effected for advancing. Depending on the conditions prevailing in the roadway and the nature of the rock, such a penetration procedure at first is effected in the region of the roof, in the center of the mine face or in the region of the mine floor. Automated cutting or excavation preconditions the precise detection of the actual penetration depth of the cutting tool. With the hitherto known proposals for the detection of the penetration depth, an undriven distance measuring wheel was carried along beside the crawler mechanism of the displaceable selective cut heading machine.

The distance covered by that distance measuring wheel during the penetration procedure is to give information on the penetration depth. Such a measuring device has definitely proved successful in case of a dry floor such as, for instance, in potassium mining. Other floor types will, however, involve measuring inaccuracies. Precise measuring in the roadway drivage region usually is ensured by means of directional control devices, with which the respective measurements are taken from a stationarily arranged theodolite. Measurements may be effected via measuring beams, which in turn may be detected via receiver means provided on the mining machine and evaluated subsequently. Thus, separate means provided in the roadway are necessary for such devices, wherein distortions of the measuring results cannot be excluded, in particular in case of bad floor conditions and Spoor visibility in the region of the mining machine. Also z4- 2 indirect distance measuring by directly monitoring the travelling movement of the crawler mechanism will not result in the desired precision, since slips due to uneven, dirty and wet floors are not taken into account so that measured data that are useless may be obtained.

From the publication Devy M. et al.: ,Mining Robotics: Application of Computer Vision to the Automation of a Road Header", Robotics and Autonomous Systems, Vol. 11, No. 2, 1 September 1993, pp. 65-74, has already been known a device for controlling the cutting process of heading machines, in which an ultrasonic distance sensor is provided for determining the distance to the mine face in addition to other control means so as to enable automatic cutting. The data of the distance sensor and the other control means are fed to an evaluation means and used in calculating an excavation plan.

The invention aims at providing a device of the initially defined kind, which enables the achievement of sufficiently precise measuring results for the penetration depth within the roadway even with bad floor conditions and poor visibility in the region of the mining machine without requiring special means. The device is to be of simple construction, offering an operating safety at any time even in the rough mining operation. To solve this object, the device according to the invention essentially consists in that at least two distance sensors oriented towards the mine face are arranged in the region of the pivot mechanism of the mining machine, each measuring the regions in front of and behind the cutting track of the picks of the cutting heads, and that the distance sensors are connected to an evaluation means with the sensor signals being fed to a comparator circuit for evaluating signal differences. By arranging in the region of the pivot mechanism of the mining machine at least two distance sensors oriented towards the mine face, a distance measurement is directly taken over as short a distance as possible, and hence i a better consistency even in case of poor visibility, with 3 the excavation movement during advancing being taken into account. As the cutting tools sweep over the mine face after excavation has been started, a larger depth results in the path of the cutting tools behind the cutting tools, which is opposed by a slighter depth in front of the cutting tools. The distance sensors may be arranged stationarily or so as to be pivotable along with the pivot mechanism such that a measurement is each taken immediately in front of and behind the cutting tool, thereby enabling appropriate comparison by difference formation. Improvement of the measuring results by averaging out peak values may be effected in that, as in correspondence with a preferred embodiment, the distance sensors are arranged in a pivotable manner. By means of such pivotable sensors, a relatively large region of the mine face may be scanned, wherein peak values can be filtered out so as to improve the measured result. Direct information on the region in the immediate vicinity of the cutting heads or cutting tools may be ensured in that the distance sensors are arranged on the same level of the mining machine.

As already indicated, the evaluation of the penetration depth in a particularly simple manner is effected by difference formation, to which end the sensor signals are fed to a comparator circuit for evaluating signal differences. The respectively larger measured value for the distance reduced by the respectively lower measured value for a distance measured on another point directly results in the excavation depth and hence the desired information.

In a particularly simple manner, the signals measured at the beginning of the measuring procedure may be compared with, and related to, the geometric data of the mining machine so as to enable initial value calibration. By continuously comparing the measured data of two sensors, any irregularities in the mine face such as thrusts or large pieces of rock falling down can be eliminated from evaluation. The detection of the Ri&,cncretely given excavation depth allows for, at any time, to -0 7> 4 compare such measured data with the floor data for cutting in certain rock types or allowances in regard to subsequent roadway drivage.

Another option to evaluate measured data for the distance to the mine face consists in that the sensor signals in the evaluation means are compared with sensor signals detected by lateral distance sensors known per se. In this manner, any displacement of the machine may be taken into account as well, such lateral distance sensors being described, for instance, in DE-A1 44 39 601.

Further excavation, as a rule, is not to be effected unless the loading device has been sufficiently cleared, since otherwise problems will arise in respect of excavated material haulage. The distance sensors oriented in the direction towards the mine face again allow for the obtainment of an additional information, wherein the configuration advantageously is devised such that the sensors and/or an additional sensor are capable of being oriented towards the lower region of the mine face and that the signals of these sensors are connected to the excavation actuator via an evaluation circuit. If such a measurement reveals a high filling degree of the loading device, any further excavation procedure may be delayed until haulage has been effected to the required extent.

In the following, the invention will be explained in more detail by way of an exemplary embodiment schematically illustrated in the drawing. Therein, Fig. 1 is a side view of a mining machine comprising the device according to the invention and Fig. 2 is a top view on the illustration according to Fig. 1.

Fig. 1 depicts a selective cut heading machine 2, which is displaceable on a crawler mechanism 1 and whose pivoting mechanism is denoted by 3. An extension arm 4 pivotable in 1) 5 height and laterally is hinged to the pivoting mechanism, the pivoting mechanism itself being pivotable in the horizontal direction about axis 5. The extension arm 4 carries cutting heads 6, which, in the illustration according to Fig. i, are illustrated in a manner penetrating into the mine face over a penetration depth te. The advance motion for reclaiming rock is effected by pivoting the pivoting mechanism 3 about the substantially vertical axis 5 in a substantially horizontal direction. Distance sensors 7 are arranged adjacent the pivoting mechanism, such distance sensors being arranged on both sides of the pivoting mechanism 3 as is apparent, in particular, from the top view according to Fig. 2. The righthand distance sensor, viewed in the longitudinal direction of the machine, is denoted by 7, while the opposite sensor is denoted by 8. Sensors 7 and 8 themselves may be arranged stationarily, or they may be pivotably hinged to the mining machine 2. Pivoting in a substantially vertical direction causes the mine face to be scanned over a region in which excavation has already occurred such that the respectively largest measured value corresponds to the distance from the mine face plus the penetration depth te. The distance sensors may be designed in a conventional manner, for instance, as ultrasonic sensors, and operated in the manner of an echo depthsounder. Alternately, other radiation sources such as, for instance, infra red radiation may be used for the sensor, wherein the respective distance may each be concluded from the difference of the propagation time between the signal emitted and the signal reflected.

In the illustration according to Fig. i, a heap of debris is to be seen on a loading means 9, wherein, as shown in Fig.

1, a relatively high filling level is feasible depending on the pivoted position of the extension arm 4. The distance relative to the heap of debris likewise may be measured by means of the sensors 7 and 8, or also by separate sensors, wherein too small a distance will reveal too high a filling level of the loading means 9. If the filling level is too 4,9 1 T leve 6 high, further excavation cutting may be interrupted until haulage has been effected to the desired extent while enlarging the distance measured to the heap of debris As as apparent, in particular, from the top view according to Fig. 2, the regions in front of and behind the cutting track of the picks of the cutting heads 6 are each measured by the sensors 7 and 8, respectively. The extension arm 4 during cutting is pivoted in the direction of arrow 11, wherein the respectively larger distance plus the penetration depth is measured in the already cut partial region in the track of the cutting heads. A sensor 8 directed into this track, thus, measures a higher value for the distance than the sensor 7 such that the penetration depth te can be immediately determined from the difference of these signals. At the end of the pivoting path in the direction of arrow 11, pivoting of the extension arm 4 is usually effected in the vertical direction with a new cut being made by a return of motion opposite to the direction of arrow 11. In those cases, the measured values of the distance sensor 7 will be larger than the measured values of the distance sensor 8.

The material impinging on the loading device via a continuous conveyor 12 is conveyed to the throw-off or delivery end 13 of that conveyor and subsequently may be further transported off in a conventional manner.

Claims

1. A device for detecting the penetration depth of cutting tools of mining machines into the mine face, characterized in that at least two distance sensors 8) oriented towards the mine face are arranged in the region of the pivot mechanism of the mining machine each measuring the regions in front of and behind the cutting track of the picks of the cutting heads and that the distance sensors 8) are connected to an evaluation means with the sensor signals being fed to a comparator circuit for evaluating signal differences-

2. A device according to claim i, characterized in that the distance sensors 8) are arranged in a pivotable manner.

3. A device according to claim 1 or 2, characterized in that the distance sensors 8) are arranged on the same level of the mining machine

4. A device according to any one of claims 1, 2 or 3, characterized in that the sensor signals are processed in the evaluation means together with sensor signals detected by lateral distance sensors known per se. A device according to any one of claims 1 to 4, characterized in that the sensors 8) and/or an additional sensor are capable of being oriented towards the lower region of the mine face and the signals of these sensors are connected to the excavation actuator via an evaluation circuit. f4 RT Lii)'