GB1565179A - Device for inserting a power supply cable into a mineral-mining maschine - Google Patents

Description

(54) IMPROVEMENTS RELATING TO A DEVICE FOR INSERTING A POWER SUPPLY CABLE INTO A MINERAL-MINING MACHINE (71) We, GEBR. EICKHOFF MAS CHINENFABRIK U. EISENGIESSEREI mbH., a German Body Corporate, of Hunscheidtstrasse 176, Bochum 4630, Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to a device for inserting a power supply cable into a mineral-mining machine, such as a drum cutter machine, which is provided with a strainabsorbing bush adapted to retain the power supply cable on the machine side.

Prior art devices incorporate breakage safety devices for power cables which are disposed in trailing chains. These breakage safety devices incorporate a component of preferred frangibility situated in the trailing chain at a constantly supervised place preferably near the operating stand of the mineral-mining machine. The component of preferred frangibility also contains a failsafe conductor loop which is connected via a fail-safe coupling element to the switch of the mineral-mining machine and switches off the latter through the coupling element in the event that the component of preferred frangibility is destroyed. Finally, a mechanical safety device is provided which bridges the component of preferred frangibility in the trailing chain and supports the latter after the said component is destroyed.This kind of breakage safety device ensures that cable fractures hardly ever occur at a mineral face. However, breakage of the trailer chain - even if this occurs at a defined place where the damage can be rapidly repaired cannot be avoided.

It is an object of this invention to be able to insert a power supply cable into the mineral-mining machine so that the stresses which occur on the cable may be measured and the machine can be switched off if permissible stress limits are exceeded or not reached.

Accordingly, this invention provides a device for inserting a power supply cable into a drum cutter machine or other mineral-mining machine, which device is provided with a strain-absorbing bush adapted to retain the cable on the machine side, and supported so as to be slidable in its axial direction. the bush bearing upon a load cell arranged to deliver an output signal which is proportional to the stress in the cable via a signal conductor connected to an evaluator which is connected to a shutdown device for the machine.

The evaluator can be constructed to compare the measured signals of the load cell, corresponding to the appropriate stress in the cable, with specified set point signals, delivers an output signal only if the stress values exceed or do not reach specified stress limits for the cable and shuts down the machine as soon as such limits are exceeded or not reached. A device which operates in this manner is particularly advantageous if a truck guides the cable within a side bracket and maintains both runs of the cable under a constant specific tensile stress so as to avoid the formation of loops with the consequent sharp kinking of the cable within the side bracket space in the event of brief changes in the direction in which the machine travels.

If the end of the cable enters the machine in arcuate configuration the device can be constructed so that it accommodates the strain-absorbing bush in a bore which extends transversely to the machine travelling direction and bears on the load cell, which closes the bore, by means of a sleeve the circumference of which is provided with a slot-like opening for the cable. The strainabsorbing bush is therefore able to transfer the cable forces which act on it into the load cell via the sleeve even if the cable is curved and the load cell then supplies the evaluator with an output signal which corresponds to the prevailing stress.

It is also advisable to extend the sleeve at least into the plane of the cable portion which is parallel with the machine travelling direction and to close the said sleeve at the endface by means of a thrust disc which bears on the load cell, the load cell being disposed in an insert which closes the bore of the device. The load cell in a device constructed in this manner is also easily accessible from the outside and can be readly inspected or exchanged where necessary in the event of defects.

The invention may be performed in various ways and a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates a double-drum cutter machine provided with the cable insertion device according to the invention in plan view but with a side bracket shown in section; Figure 2 is a side view of the double-drum cutter machine again with the side bracket shown in section; Figure 3 is a partially sectioned plan view of the cable insertion device shown in detail; Figure 4 shows the cable insertion device in a view taken in the direction of the arrow X in Figure 3, and Figure 5 is a block circuit diagram of control apparatus for use with the doubledrum cutter machine.

The mineral-mining machine illustrated in Figure 1 is a double-drum cutter machine 1 which can traverse on a face conveyor 2 and is supplied via a cable 3 with driving energy and via a hose 4 with fluid necessary to suppress dust and to cool its prime mover and its winch.

A side bracket 5 closes off the face conveyor 2 on the goaf side. In its interior it houses a truck 6 which in this case can traverse along the longitudinal direction of the roadway and, by means of a sheave 8, which is rotatably supported about the axis 7, maintains the cable 3 as well as the hose 4 taut and guides them in a loop. The doubledrum cutter machine 1 is therefore able to change its direction of travel at will without causing double loops of the cable 3 or of the hose. A winch installed at the end of the roadway (but not shown) maintains the truck 6 under the necessary pre-stress by means of a traction element 9 and moves said truck in one or the other direction depending on the travelling direction of the double-drum cutter machine 1.

The double-drum cutter machine 1 engages, by means of a device 10, through the longitudinal slot 11 (Figure 2) of the bracket wall on the face side into the interior space of the side bracket and transfers the end of the hose 4 as well as the end of the cable 3 into the machine body. As can be seen by reference to Figure 4, the device 10 comprises two halves 10a, 10b which are connected to each other by means of bolts 12 or stressing pins 13 (Figure 3) and the hose 4 and the cable 3 enter through an opening 14 into the interior of the device 10. The hose 4 as well as the cable 3 are bent at right-angles and the cable 3 is retained by means of a straining bush 15, situated in a bore 16 of the device 10 and extending at right-angles to the machine travelling direction.At its end nearest to the double-drum cutter machine 1 the straining bush 15 bears on a bore shoulder 17 while the other end of the bush bears on a sleeve 18 which is also disposed in the bush and has a slot-shaped circumferential opening 19 through which the cable 3 enters into the sleeve 18 and then into the straining bush 15. The sleeve end which projects beyond the cable 3 is closed by a thrust disc 20 which bears on the endface side against a load cell 21 disposed in an insert 22 which closes the bore 16 of the device 10.

A conductor 23 connects the load cell to an amplifier 24 (Figure 5) which is supplied with voltage via a conductor 25 and whose output is connected via a conductor 26 to a matching element 27. The output signal of the amplifier 24 is adjusted in the matching element 27 to the voltage level suitable for an analog-digital converter 28 and is supplied thereto via a conductor 29. Two outputs from the analog-digital converter 28 communicate via conductors 30, 31 to respective elements 32 and 33.In the element 32 the output signal of the analog-digital converter is compared with the specified set point signal of variable magnitude, corresponding to the minimum acceptable tensile stress in the cutter cable 3 while in the element 33 the output signal of the analogdigital converter is compared with a set point signal of variable magnitude corresponding to the maximum acceptable tensile stress of the cutter cable 3. If the level of the output signal delivered by the analog-digital converter 28 falls below the minimum or exceeds the maximum of the two set points the resultant output signal of the element 32 or 33 will shut down the prime mover of the double-drum cutter machine 1 and prevent any further machine motion.

WHAT WE CLAIM IS: 1. A device for inserting a power supply cable into a drum cutter machine or other mineral-mining machine, which device is provided with a strain-absorbing bush adapted to retain the cable on the machine side, and supported so as to be slidable in its axial direction, the bush bearing upon a load cell arranged to deliver an output signal which is proportional to the stress in the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. and the load cell then supplies the evaluator with an output signal which corresponds to the prevailing stress. It is also advisable to extend the sleeve at least into the plane of the cable portion which is parallel with the machine travelling direction and to close the said sleeve at the endface by means of a thrust disc which bears on the load cell, the load cell being disposed in an insert which closes the bore of the device. The load cell in a device constructed in this manner is also easily accessible from the outside and can be readly inspected or exchanged where necessary in the event of defects. The invention may be performed in various ways and a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates a double-drum cutter machine provided with the cable insertion device according to the invention in plan view but with a side bracket shown in section; Figure 2 is a side view of the double-drum cutter machine again with the side bracket shown in section; Figure 3 is a partially sectioned plan view of the cable insertion device shown in detail; Figure 4 shows the cable insertion device in a view taken in the direction of the arrow X in Figure 3, and Figure 5 is a block circuit diagram of control apparatus for use with the doubledrum cutter machine. The mineral-mining machine illustrated in Figure 1 is a double-drum cutter machine 1 which can traverse on a face conveyor 2 and is supplied via a cable 3 with driving energy and via a hose 4 with fluid necessary to suppress dust and to cool its prime mover and its winch. A side bracket 5 closes off the face conveyor 2 on the goaf side. In its interior it houses a truck 6 which in this case can traverse along the longitudinal direction of the roadway and, by means of a sheave 8, which is rotatably supported about the axis 7, maintains the cable 3 as well as the hose 4 taut and guides them in a loop. The doubledrum cutter machine 1 is therefore able to change its direction of travel at will without causing double loops of the cable 3 or of the hose. A winch installed at the end of the roadway (but not shown) maintains the truck 6 under the necessary pre-stress by means of a traction element 9 and moves said truck in one or the other direction depending on the travelling direction of the double-drum cutter machine 1. The double-drum cutter machine 1 engages, by means of a device 10, through the longitudinal slot 11 (Figure 2) of the bracket wall on the face side into the interior space of the side bracket and transfers the end of the hose 4 as well as the end of the cable 3 into the machine body. As can be seen by reference to Figure 4, the device 10 comprises two halves 10a, 10b which are connected to each other by means of bolts 12 or stressing pins 13 (Figure 3) and the hose 4 and the cable 3 enter through an opening 14 into the interior of the device 10. The hose 4 as well as the cable 3 are bent at right-angles and the cable 3 is retained by means of a straining bush 15, situated in a bore 16 of the device 10 and extending at right-angles to the machine travelling direction.At its end nearest to the double-drum cutter machine 1 the straining bush 15 bears on a bore shoulder 17 while the other end of the bush bears on a sleeve 18 which is also disposed in the bush and has a slot-shaped circumferential opening 19 through which the cable 3 enters into the sleeve 18 and then into the straining bush 15. The sleeve end which projects beyond the cable 3 is closed by a thrust disc 20 which bears on the endface side against a load cell 21 disposed in an insert 22 which closes the bore 16 of the device 10. A conductor 23 connects the load cell to an amplifier 24 (Figure 5) which is supplied with voltage via a conductor 25 and whose output is connected via a conductor 26 to a matching element 27. The output signal of the amplifier 24 is adjusted in the matching element 27 to the voltage level suitable for an analog-digital converter 28 and is supplied thereto via a conductor 29. Two outputs from the analog-digital converter 28 communicate via conductors 30, 31 to respective elements 32 and 33.In the element 32 the output signal of the analog-digital converter is compared with the specified set point signal of variable magnitude, corresponding to the minimum acceptable tensile stress in the cutter cable 3 while in the element 33 the output signal of the analogdigital converter is compared with a set point signal of variable magnitude corresponding to the maximum acceptable tensile stress of the cutter cable 3. If the level of the output signal delivered by the analog-digital converter 28 falls below the minimum or exceeds the maximum of the two set points the resultant output signal of the element 32 or 33 will shut down the prime mover of the double-drum cutter machine 1 and prevent any further machine motion. WHAT WE CLAIM IS:

1. A device for inserting a power supply cable into a drum cutter machine or other mineral-mining machine, which device is provided with a strain-absorbing bush adapted to retain the cable on the machine side, and supported so as to be slidable in its axial direction, the bush bearing upon a load cell arranged to deliver an output signal which is proportional to the stress in the

cable via a signal conductor connected to an evaluator which is connected to a shutdown device for the machine.

2. A device according to claim 1, wherein the evaluator is programmed to deliver a signal to operate the shutdown device if the stress in the cable exceeds a specified maximum stress or falls below a specified minimum stress of the cable.

3. A device according to claim 1 or claim 2, which is constructed so as to cause the cable end to enter in an arcuate configuration into the machine, the device accommodating the strain-absorbing bush in a bore which will extend transversely to the machine travelling direction and which bears upon a sleeve whose circumference is provided with slot-like opening for accommodating the cable, the sleeve in turn bearing on the load cell which closes the bore.

4. A device according to claim 3, wherein the sleeve extends at least into the plane of the cable portion which will be parallel with the machine travelling direction and is closed at that end of the endface side by means of a thrust disc which bears upon the load cell, the load cell being situated in an insert which closes the bore.

5. A device according to any one of claims 1 to 4, when associated with a truck provided to guide the cable within a side bracket of a conveyor for the machine.

6. A device for inserting a power supply cable into a mineral-mining machine substantially as herein described with reference to the accompanying drawings.