The invention relates to a plough for underground mining, more specifically to a coal plough, with a plough body that is guided along a plough guide, wherein the plough body has at least one foot piece which receives a sliding skid having at least one contact surface formed on its underside that slides on a rail of the plough guide when the sliding skid is in its operating position.
Such a plough with a sliding skid is known, for example, from U.S. Pat. No. 4,583,785 (Breuer et.al). The known plough, with its plough body equipped with cutting tools, is guided along a plough guide and is connected by one foot piece each at both of its two ends to an exchangeable sliding skid. Here, each sliding skid has a guide shoe in which the foot piece is supported.
When the plough is in operation, the sliding skids slide with a sliding surface provided on their underside on a rail of the plough guide. The sliding skids are subjected to an especially high rate of abrasion/wear due to the weight of the plough and the high forces that must be transmitted from the sliding skids onto the rail during operation of the plough. For this reason, the sliding skids are releasably attached to the plough body so that worn sliding skids can be simply and rapidly replaced.
However, the replacement of worn sliding skids is associated with comparatively large amounts of effort and high costs. The sliding skids as a whole are comparatively complex components and are expensive to produce. Their replacement can take a relatively long time and during this time the plough is out of commission, meaning that no coal can be extracted during this period.
The object of the invention is to create a plough of the type mentioned above with at least one sliding skid that does not only have a long operational life but that is also cheap to manufacture and utilise.
This object—among others—is achieved with the invention in that the sliding skid has at least one wear inlay on its underside, preferably in the area of the highest load. The sliding skid that is provided with the wear inlay can withstand the high mechanical loads for a longer period of use than hitherto-known runners. To this end, a more wear-resistant material which can even be more expensive than the base material of the sliding skid is used efficiently in a concentrated manner in the area of the highest load. In this way, the sliding skid preferably only slides on the wear inlay or on the wear inlays.
In a preferred embodiment of the invention, the sliding skid is configured as a hinged runner that can be connected in a swivelling manner with the foot piece in a plane perpendicular to the seam, whereas the swivelling axis extends at a right angle to two oppositely directed sliding directions of the sliding skid, and whereas at each of the sliding skids one wear inlay is provided in front of the swivelling axis and one wear inlay is provided behind the swivelling axis. The force that acts upon the sliding skid is then distributed onto the two wear inlays wherein the ratio of partial forces that are to be absorbed corresponds to the inverse ratio of the effective levers of the wear inlays about the swivelling axis. Here, the effective levers correspond, in good approximation, to the distances between the centre of gravity of the surfaces of the two sliding surfaces of the wear inlays and the swivelling axis in the sliding direction.
It is possible that the distance from one wear inlay to the swivelling axis is approximately twice as large as the distance from the other wear inlay to the swivelling axis. This means that the one wear inlay must absorb a load that is twice as large as that absorbed by the other wear inlay. It can therefore be expedient that the wear inlay that is disposed closer to the swivelling axis has a greater effective area and/or a higher resistance to wear so that approximately uniform wear of the two wear inlays is attained. If, on the other hand, the distance between one wear inlay and the swivelling axis is very small, this wear inlay would have to bear almost the entire load which would lead to a corresponding uneven wear of the wear inlay.
It is preferred that the distances from the two wear inlays to the swivelling axis are at least approximately equal. Such a configuration means that the two wear inlays are subjected to approximately equal loads and are therefore subjected to approximately the same rate of wear.
The wear inlay(s) can be sintered with hard metal whereby a high resistance to wear is attained. The individual wear inlay can also have hard metal pins that are cast in a matrix that is made, for example, from cast steel. In turn, this matrix can be supported by a base plate, preferably of a weldable material. The hard metal pins can be disposed in the wear inlay so that they extend transverse to the sliding direction of the sliding skid. Their circumferential contour can be configured so that they neither have nor form sharp edges, even when wearing, that could cause damage to the fixed rail.
It is preferred that the wear inlay is disposed on the underside of the sliding skid in a manner so as to be exchangeable. Attachment can be, for example, via a bolted connection. However, it is preferred that the wear inlay is soldered or welded to the underside of the sliding skid.
The wear inlay is expediently configured as a wear plate that is embedded in a suitable, preferably substantially rectangular recess on the underside of the sliding skid. Here, the wear plate can be flush with the underside or can project slightly.
In an advantageous development of the invention, the underside of the sliding skid is bulged outwards in at least a partial section, whereas this partial section accepts a wear inlay in such a way that essentially only this rests on the rail. In this way, it can be ensured that wear does not take place in an area of the sliding skid where no wear-resistant material is provided.
It is preferred that the sliding skid is provided with a hook attachment that includes a rising limb that is at a distance from the guide shoe and, together with the guide shoe, forms an approximately U-shaped holding fixture that is open in the upward direction for a downwardly directed guide bar of the plough guide. In use, the sliding skid is therefore also guided by the guide bar, which is enclosed by the limb and the guide shoe, in the lateral direction, i.e. transverse to the longitudinal direction of the rail.
The guide shoe preferably has a raised shoulder on its side facing the rising limb. Here, the height of the shoulder, based on a transverse web of the hook attachment that connects the rising limb and the guide shoe, can be greater than that of the limb. The raised shoulder offers a large contact surface for the guide bar, which reduces wear in this area. Wear inlays can also be provided on an inner side of the limb and/or on the surface of the shoulder facing the limb.
The guide shoe can have an insertion slot that is open in the upward direction into which the foot piece of the plough can be inserted, whereas a front-wall wall limitation of the insertion slot is formed as a socket, via which the sliding skid together with the correspondingly shaped foot piece of the plough forms a swivellable connection.
Further features and advantages of the invention are presented in the following description and in the drawings, in which a preferred embodiment of the invention is explained in greater detail by means of an example. It shows:
The plough guide 4 has a lower rail 6, on which a plough body 7 is supported on both of its two front-side ends by means of sliding skids, of which only one, namely the sliding skid 8, is visible in
The plough guide 4 has an upwardly directed guide rail 13 at its apex. An upper guide pawl 14 of the plough body engages around the guide rail 13 like a hook. Between the guide pawl 14 and the guide rail 13 a U-shaped guide piece 15 is provided that is exposed to increased wear and is therefore releasably and exchangeably attached to the guide pawl 14. Crane lugs 16 are disposed on an upper side of the plough body 7, via which it can be lifted with suitable lifting means.
The sliding skid 8 slides with its underside 17 on the rail 6. It has a lateral guide shoe 18 into which a downward facing foot piece (covered, not illustrated), disposed on the plough body 7, engages. The weight pressure of the plough 7 and the forces that act upon the plough when it is in use are transmitted via the foot piece into the sliding skid 8 and thus onto the plough guide 4. The sliding skid 8 also forms a U-shaped holding fixture 19 that engages around a downwardly directed guide bar 20 on the plough guide from below, so that lateral forces, that is, forces transverse to the direction of movement of the plough body, can be transferred into the sliding skid 8.
The dashed lines in
As can also be seen in
The swivelling axis of the swivel connection between the foot piece of the plough body 7 and the sliding skid 8 extends perpendicular to the two sliding directions of the sliding skid as indicated by the double-headed arrow 32 in
The wear inlay 26 is indented slightly over approximately half its length on its side facing the insertion slot 29 so that insertion of the foot piece of the plough 7 is not hindered. Naturally, the wear inlay 26 could be disposed further away from the insertion slot 29. However, this would mean a greater distance from the swivelling axis, wherein the load on the other wear inlay 25 would be correspondingly greater.
Number | Date | Country | Kind |
---|---|---|---|
20 2004 000 516 U | Jan 2004 | DE | national |
Number | Name | Date | Kind |
---|---|---|---|
4583785 | Breuer et al. | Apr 1986 | A |
6000117 | Bain | Dec 1999 | A |
Number | Date | Country |
---|---|---|
19637226 | Mar 1998 | DE |
2100600 | Dec 1997 | RU |
Number | Date | Country | |
---|---|---|---|
20050151412 A1 | Jul 2005 | US |