Patent Application
20150275664
The present disclosure relates to an extraction machine. More particularly, the present disclosure relates to an extraction machine of an extraction installation for mineral extraction.
The present disclosure is based on an extraction installation and an extraction machine together with traction carriage according to DE 10 2006 027 955 A1 and DE 10 2007 053 206 A1. In the generic extraction installation, the chain ends of an endless drive chain for the extraction machine formed as a coal plow are arranged on a traction carriage. The traction carriage, via a resilient element as coupling device, designated as a damping device, is arranged movably to a limited degree against the restoring force of plate spring assemblies in a recess in the extraction body of the extraction machine.
For illustration,
If a schematically indicated working face 508 is worked with the extraction machine 500, given a correspondingly high pre-tensioning of the spring 532, which for this purpose can consist for example of a plate spring assembly, it can be ensured that a damping effect is achieved in the normal operational behaviour of an extraction machine. The compression force of the spring 532 is for this purpose preferably greater than the tension force within the drive chain 501, since otherwise, just by virtue of the usually present chain tension of the drive chain 501 between both chain wheels 502, 503, the traction carriage housing 531 would be displaced laterally within the recess 520. The traction carriage housing 531 would be displaced laterally within the recess 520 in such a way that the housing section of the traction carriage housing 531, which is situated in each case towards the front in the direction of travel, would bear against the recess 520 and, in this respect, spring travel would no longer be available for the plunger 533. In the case of unfavourable operating states, as indicated in
The resilience of the coupling device, which is effective between traction carriage 530 and machine body 506, makes it possible, during a change in the direction of travel but also during blockages or other unfavourable operating states, to prevent an impact-like mutual abutting of the contact surfaces between traction carriage and extraction machine from occurring. The generic extraction installation with a corresponding traction carriage coupled via a resilient system has proved to be successful in underground mining, in particular in the extraction of coal, and has led to a considerable improvement in the service life and the operational behaviour of the extraction machine. During operation of such an extraction installation with resilient coupling device with respect to an extraction installation with a rigidly connected plow chain or rigidly connected traction carriage, it has moreover been shown that the vibrational behaviour of the pulling chain strand section is also improved. The pulling chain strand section is also improved since the vibration amplitudes in extraction installations with extraction machines rigidly connected to the chain turn out to be substantially greater than in extraction installations with a resilient coupling device on the traction carriage. This reduction in the vibrations contributes to the reduction in the vibration loading of the chain and also of the chain locks.
Since, in a corresponding manner to the longwall length of modern underground extraction operations, the length of the extraction installations has a tendency to become ever greater for economic reasons, the drive capacities and the dimensions of the chains used must also increase. As a result, the problem of the occurrence of so-called chain sag increases. Chain sag may occur in particular in that chain strand section, which, depending on the respective direction of travel of the extraction machine, is situated behind the extraction machine pulled by chain. To avoid chain sag, the prior art proposes tensionable drive or reversal stations by means of which the spacing of the two chain wheels from one another is changed, if appropriate also during active operation of the extraction machine, so as to counteract the occurrence of chain sag by the change of spacing.
In DE 10 2007 043 043 A1, sensor devices are arranged in the drive or reversal stations, by means of which sensor devices the chain state is detected, preferably both in the upper side and in the lower side of the chain, in order, depending on the chain state detected, either to change the speed of rotation of at least one drive motor or to change the extension state of a tensioning device in the drive or reversal stations, and as a result, to counteract the occurrence of chain sag or to avoid excessive chain tensions.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.
According to an aspect of the present disclosure, an extraction machine for an extraction installation including a chain with first and second chain ends at respective first and second chain strand sections, the first and second chain ends being connectable to the extraction machine for moving the extraction machine, may comprise a first chain mount configured to be connected to the first chain strand section. The extraction machine may further comprise a second chain mount configured to be connected to the second chain strand section, and a first pre-tensioning device for building up a pre-tensioning force acting on the first chain mount such that a pulling force acts on the first chain strand section in the direction of the second chain mount.
According to another aspect of the present disclosure, an extraction installation for mineral extraction may comprise an extraction machine as exemplary disclosed herein.
According to yet another aspect of the present disclosure, a traction carriage for an extraction machine movable by means of a chain with first and second chain ends at respective first and second chain strand sections, may comprise a traction carriage body configured to be inserted into a recess in the extraction machine, the traction carriage body being provided with a first chain mount to which the first chain strand section is connectable. The traction carriage may further comprise a resilient device integrated into the traction carriage for both directions of movement. The first chain mount may be subjected by means of a first pre-tensioning device to a pre-tensioning force such that a pulling force acts on a first chain strand section in the direction of the second chain mount.
According to a further aspect of the present disclosure, an extraction installation for mineral extraction may comprise at least one extraction machine having a machine body, with a chain with two chain ends to which the extraction machine is connected via chain mounts, for moving the extraction machine, and with two chain wheels for driving and/or deflecting the chain into drive stations or deflection stations which receive the respective chain wheel. Both chain mounts may be subjected by means of at least one pre-tensioning device to a pre-tensioning force which exerts, on the chain strand section of the chain connected to the respective chain mount, a pulling force in the direction of that chain wheel around which the chain strand section connected to the other chain mount is deflected.
According to still another aspect of the present disclosure, an extraction machine for an extraction installation in particular as disclosed herein, may comprise a machine body and chain mounts to which a chain for moving the extraction machine can be connected. Both chain mounts may be subjected by means of at least one pre-tensioning device to a pre-tensioning force which exerts, on a chain strand section of the chain which can be connected or is connected to the respective chain mount, a pulling force in the direction of the other chain mount.
According to yet another aspect of the present disclosure, a traction carriage for an extraction machine as exemplary disclosed herein which can be moved back and forth by means of a chain, may comprise a traction carriage body which can be inserted into a recess in an extraction machine and which is provided with chain mounts to which a chain for moving the traction carriage body can be connected. A resilient device for both directions of movement may be integrated into the traction carriage. Both chain mounts on the traction carriage may be subjected by means of at least one pretensioning device to a pretensioning force which exerts, on a chain strand section of the chain which can be connected or is connected to the respective chain mount, a pulling force in the direction of the other chain mount.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
Further advantages and refinements of an extraction installation according to the present disclosure and of an extraction machine according to the present disclosure will emerge from the following description of exemplary embodiments shown schematically in the drawing. In the schematic drawings:
An extraction machine 50 is moved along a working face 18 to be worked by means of a drive chain 1 which is deflected on a first chain wheel 2 and a second chain wheel 3. Both chain wheels 2, 3 are arranged within schematically indicated drive stations 15 which can be provided with drive motors (not shown) and, if appropriate, also with a tensioning device for changing the distance between the two chain wheels 2, 3. In modern extraction operations, the distance between both drive stations 15 may be, for example, 400 m and more, which leads to correspondingly high chain lengths of the drive chain 1.
In the schematic illustration according to
A pre-tensioning device 40, which here comprises at least one spring 41, is provided between the two chain mounts 8, 9, which can each move on their own account relative to a machine body 6 of the extraction machine 50. Both chain mounts 8, 9 may be guided movably on the machine body 6 in such a way that they can move substantially only parallel to the direction of travel F. In the exemplary embodiment of the extraction machine 50, the spring 41 forms a tension spring, which pushes together the two chain mounts 8, 9, if the chain strand sections 1A, 1B are not connected, to a minimum distance from one another. By connecting the chain strand section 1A to the one chain mount 8 and the chain strand section 1B to the other chain mount 9 and applying a chain tension in the entire chain 1 between both chain wheels 2, 3, for example, by corrective tensioning of one of the two chain wheels, the machine-side chain mounts 8, 9 are pulled apart while building up or increasing a pretension in the spring 40. The tensile force or spring force of the spring 41 of the pre-tensioning device 40 is preferably lower by, for example, a power of ten than the chain tensioning force between both chain wheels 2, 3 that is normally introduced into the chain 1. The chain tensioning force between both chain wheels 2, 3 may be, for example, approximately 500 kN. The pre-tensioning force of the completely tensioned spring 41 within the pre-tensioning device 40 may then be, for example, 50 kN, even if these are only exemplary reference values.
The larger chain tractive force has the effect that both chain mounts 8, 9, as indicated by dot-dash line in
Therefore, in the normal operating state, both chain mounts 8, 9 are situated in direct contact with the fixed mounts 11, 12 on the machine body 6. If, however, chain sag occurs in the rearward chain strand section 1B, as is indicated with the reference sign 1B′ in
The extraction machine 150, which is provided with suitable extracting tools in order to remove material on a working face 118 in both possible directions of travel, here comprises two machine bodies 106A, 106B, which are separated from one another and which, although having a suitably large distance from one another, are connected to one another substantially fixedly in terms of movement, as is indicated here via the coupling rod 135. The chain mount 108 situated at the front in the direction of travel in the representation according to
As in the case of the previous exemplary embodiment, each pre-tensioning device 140A or 140B in each case comprises at least one spring 141A or 141B. When the extraction machine 150 travels in the direction of travel F, the chain mount 108 preferably bears against an end stop on the machine body part 106A in which the spring 141A is charged or loaded with the maximum value of its pre-tensioning force. The same applies in the normal operating state for the chain mount 109, as indicated by dotted line in
If now, owing to chain sag (not indicated in
The pre-tensioning device 240 again comprises at least one spring 241 which is arranged either directly between the machine mounts 208, 209, as illustrated, but also could be effectively arranged between the machine body parts 206A, 206B in a suitable manner. The movement path between both machine body parts 206A, 206B is preferably limited in such a way that the one machine body part 206A rigidly pulls the other machine body part 206B with it during the machine travel if the movement path is exhausted, and therefore a maximum predetermined spacing between both machine body parts is achieved.
Therefore, in the normal operating state, the two machine body parts 206A, 206B have their maximum spacing from one another, as represented by the dotted representation of the machine body part 206B in
The device 332 here comprises a spring system which interacts with the plungers 333 and which ensures an elastic coupling of the traction carriage 330 in the recess 320 in the machine body. Here, however, the chain mount 308 for the pulling chain strand 301A, when the extraction machine 350 moves in the direction of travel F, and the chain mount 309 for the rearward chain strand section 301B are not directly arranged on the machine body 306, but directly on the traction carriage housing 331, as schematically indicated in
The chain mounts 308, 309 are movable relative to the traction carriage housing 331.
One object of the present disclosure is to improve the operational behaviour of an extraction installation or an extraction machine for such an extraction installation.
To achieve this object, in an extraction installation with an extraction machine pulled by means of a chain, such as, in particular, a coal plow, it is provided that both chain mounts are biased by means of at least one pre-tensioning device to a pre-tensioning force which exerts, on the chain strand section of the chain connected to the respective chain mount, a tensile force in the direction of that chain wheel around which the chain strand section connected to the other chain mount is deflected. In an extraction machine, it is correspondingly provided that both chain mounts are subjected by means of at least one pre-tensioning device to a pre-tensioning force which exerts, on a chain strand section of the chain which can be connected or is connected to the respective chain mount, a tensile force in the direction of the other chain mount.
The solution according to the present disclosure therefore makes provision, by means of the pre-tensioning device, for introducing into the chain strand sections on or via the chain mounts an additional pre-tensioning force, which causes a relative movement of the respective chain mount and which can act automatically in the event that a “chain sag” chain state could occur in order to reduce or avoid the chain sag by corrective tensioning via the pre-tensioning device introduced between the respective chain mount and chain strand section. Since in modern extraction installations the traction chain for the extraction machine is in any case clamped between the chain wheels, the pre-tensioning force of the pre-tensioning device may be built up at the same time by introducing the chain tension between the chain drives.
According to one embodiment, both chain mounts may be provided with their own pre-tensioning device for building up a pre-tensioning force. The pre-tensioning devices may be in each case arranged between the machine body of the extraction machine and the associated chain mount and both chain mounts may be movable relative to the machine body. The pre-tensioning device may have in particular springs which are positioned in such a way that the spring force of the tensioned pre-tensioning device counteracts the chain tractive force. If, for example, the drive train may be tensioned as usual by changing the spacing of the chain wheels from one another, this causes a positional change of the chain mounts relative to the machine body, while at the same time building up a pre-tensioning force or increasing (tensioning) the pre-tensioning force of the pre-tensioning device. If then the chain tractive force during operation within the rearward, non-pulling chain strand section on the non-pulling side of the extraction machine falls below the pre-tensioning force of the pre-tensioning device, it may act with corrective tensioning of the chain sag until force equilibrium prevails again. These conditions are reversed with each direction reversal of the extraction machine and the rearward chain is tensioned, by virtue of the stored pre-tensioning force, in each case with the minimum required tractive force from the extraction machine. In order to correctively tension the chain sag, use is then made of the available movement path of the chain mounts relative to the machine body.
The same effect may also be achieved if, according to an alternative embodiment, only one pre-tensioning device for building up a pre-tensioning force may be arranged between the two chain mounts, wherein both chain mounts may then be movable relative to the machine body.
In yet a further alternative embodiment, the extraction machine may have a machine body with at least two machine body parts which are arranged at a distance from one another and connected to one another fixedly in terms of movement, wherein in each case one of the chain mounts may be arranged on one of the two machine body parts, can be moved relative to the associated machine body part and may be provided with its own pre-tensioning device for building up a pre-tensioning force, which acts between the respective chain mount and the associated machine body part.
In all of the aforementioned embodiment variants, in operational use, the chain mounts may be guided movably in guides on the machine body parallel to the direction of movement of the extraction machine.
According to yet a further alternative embodiment, the extraction machine may have two machine body parts which can be moved relative to one another and which can be varied in their distance from one another, wherein the pre-tensioning device acts and may be arranged between the two machine body parts, which can be moved with respect to one another. It is particularly advantageous here, if by varying the distance, a restoring force may be built up or is built up in the pre-tensioning device and/or in a separate restoring device for the machine body parts.
The solution according to the present disclosure may be particularly advantageous if the machine body of the extraction machine may be indirectly connected to the chain via a traction carriage. The traction carriage may be provided with a resilient, in particular elastically resilient, device for both directions of movement of the extraction machine and may be inserted into a recess in the machine body. Both chain mounts together with pre-tensioning device(s) may be arranged on the traction carriage provided with the preferably elastically resilient device. By means of the resilient system installed in the traction carriage, it is then possible at the same time and in a manner known per se to prevent the occurrence of increased vibration amplitudes and to achieve a better profile of the motor currents and motor speeds of rotation of the drive motors used for driving the chain wheels. By means of the resilient system, resonant vibrations in the rearward chain strand section may be prevented when switching the motors on or off, and the pre-tensioning device may cause a change in position of the respective chain mount and thus a change in length of the chain strand section is also counteracted.
Also in the embodiment with a traction carriage, either both chain mounts may be provided with their own pre-tensioning device for building up a pre-tensioning force, wherein the pre-tensioning devices may be in each case arranged between a traction carriage housing and the associated chain mount. Both chain mounts can be moved relative to the traction carriage housing. Alternatively, a common pre-tensioning device for building up a pre-tensioning force may be arranged between the two chain mounts, wherein both chain mounts can be moved relative to a traction carriage housing. Here, too, it may be advantageous if the chain mounts may be guided movably in guides on the traction carriage housing, which are arranged so as to be oriented parallel to the direction of movement of the extraction machine.
In all of the embodiments, it may be preferable for the pre-tensioning device to comprise at least one spring and, if appropriate, for the pre-tensioning force of this spring to be built up by a change in position of the two chain mounts relative to one another. The adjustment travel of the chain mounts, in particular when correctively tensioning chain sag, may be detected, if appropriate, and may be used for installation control or drive control.
The above object may also achieved by a traction carriage for an extraction machine, which can be moved back and forth by means of a chain. The traction carriage may comprise a traction carriage body, which can be inserted into a recess in the extraction machine and which is provided with chain mounts to which a chain for moving the traction carriage body can be connected. A resilient device for both directions of movement may be integrated into the traction carriage, which device preferably may ensure an elastic coupling of the traction carriage and hence of the plow chain to the plow body, wherein it may be provided according to the present disclosure that both chain mounts on the traction carriage are subjected by means of at least one pre-tensioning device to a pre-tensioning force. The pre-tensioning force exerts, on a chain strand section of the chain which can be connected or is connected to the respective chain mount, a tensile force (pulling force) in the direction of the other chain mount.
Numerous modifications, which are intended to fall within the scope of protection of the following claims are obvious to a person skilled in the art from the preceding description. It will be understood that, with each direction reversal of the extraction machine, the conditions of the pulling chain strand section and of the rearward chain strand section are reversed and, correspondingly, with the occurrence of chain sag, the other chain mount would be moved away via the pre-tensioning device if the chain tractive force in the rearward chain strand section drops and chain sag could have occurred in this respect. The pre-tensioning device(s) on the extraction machine may be designed in such a way that they can correctively tension at least twice the distance by which the chain wheels can be moved apart by means of tensioning devices in the drive or reversal stations. Each pre-tensioning device may also have a plurality of springs or other devices for applying a pre-tensioning force. The resilient device in the traction carriage preferably comprises springs or spring systems such as a plate spring assembly in order to be able to withstand the high forces, which may occur. Instead of elastic (damping) systems with springs, it could also be possible to use purely hydraulic or pneumatic damping systems or combination systems with springs. One of the stations receiving the chain wheel may also form a driveless, preferably tensionable reversal station.
Although the preferred embodiments of this invention have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2012 104 441.2 | Nov 2012 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2013/003439 | 11/14/2013 | WO | 00 |
