Abstract:
A mining plough for plough systems for the exploiting of minerals in inclined formations. In order to provide a mining plough and a plough system, with which coal seams, in particular seams in steep formation can be exploited economically and with high operating safety, the mining plough includes a separable plough body having two plough body basic elements each being provided with a fixture for a separate traction means and with a guide means for moving the coal plough by means of at least two traction means and for guiding the coal plough on at least two mutually spaced guide mechanisms.

Description:
The invention relates to a mining plough for plough systems for the working of coal or minerals in inclined formation, in particular for the working of coal seams in steep formation, having a fixture for fastening at least one traction means for the movement of the mining plough and having at least one guide means for guiding the mining plough on a guide mechanism of the plough system. The invention also relates to the plough system for the working of minerals in inclined formation, in particular for the working of coal seams in steep formation, having a mining plough, having at least one traction means for the movement of the mining plough along a coal face, and having a guide mechanism, which is placed or placeable along a coal face and on which the mining plough is forcibly guided by means of guide means. 
     BACKGROUND OF THE INVENTION 
     In the last two decades, the automatic mechanization of the working of flat-stratified coal seams with 0-20 gon (0 to 18 degrees) dip and slightly inclined deposits with 20-40 gon (18 to 36 degrees) dip has led to outputs of up to 1500 t/h with mining ploughs in plough systems and of over 2600 t/h with shearers. Nowadays, the volume of coal which is worked underground stems more than 90% from flat or slightly inclined deposits, since with existing mining technology these can be worked considerably more economically than coal seams or other mineral seams in heavily inclined formation with more than 40 gon (36 degrees) dip, or in steep formation with 60 gon to 100 gon (54 to 90 degrees) dip. 
     For the working of coal in inclined formation, in particular in steep formation, mostly baseplate plough systems or portal-type plough systems have most recently been used, and DE 32 45 515 C2 describes by way of example a plough system for the working of steeply stratified coal seams with a dip of more than 60°. In this baseplate plough system for steep formation, the guide mechanism consists of a chain channel profiled roughly in a C-shape, in which the plough baseplate engages with a guide block. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a mining plough and a plough system, with which mining deposits, in particular coal seams, including semi-steep inclined seams and, in particular, seams in steep formation, can be exploited economically and with high operating safety. 
     This object and others are achieved according to the invention, with respect to the mining plough, by the fact that the mining plough has a separable plough body having two plough body basic elements, each plough body basic element being provided with a fixture for a separate traction means for moving the coal plough by means of at least two traction means and, in addition, with a guide means for guiding the coal plough on at least two mutually spaced guide mechanisms. The mining plough according to the invention is hence no longer moved parallel to the coal face only by means of one traction means, as is normally the case in the prior art, but by means of two traction means. At the same time, each of the two plough body basic elements is guided with guide means on a separate guide mechanism, whereby a uniform guidance of the separable plough body is achieved overall. As a result of the divisibility of the plough body, which divisibility is preferably provided according to the invention, it is possible in a relatively simple manner, by conversion of the plough body, as will be more fully explained further below, to successfully adapt to another working height, so that, through the reusability of the same elements for the working of mining deposits, in particular coal seams, of different thickness, the operating efficiency of the mining plough according to the invention is improved. 
     For the working of mining deposits of different working height with the mining plough according to the invention, it is particularly advantageous if the plough body basic elements can be connected directly to each other by means of fastening means to form a plough body having a first working height. Moreover, the connection of the two plough body basic elements by means of the fastening means to form a sufficiently stable plough body makes the underground inbound and outbound transport of the plough body and, in particular, also the assembly in the steep deposits, considerably easier, since the weight of the plough body is at least halved by the division into the two plough body basic elements. In order to increase the operating efficiency of the mining plough, it is further advantageous, if at least one plough body intermediate element is provided, which can be connected to the two plough body basic elements by means of fastening means, to form a plough body having a working height which is greater than the working height of a plough body consisting just of the fastened together plough body basic elements. Through the choice of different plough body intermediate elements, or else through the stringing together of a plurality of mutually identically constructed plough body intermediate elements, the design of the mining plough allows the plough body to be set step-by-step to different working heights, and thus to different thicknesses of the mining deposits to be worked. Expediently, both each plough body basic element and, where present, each plough body intermediate element has locking means for the fastening means, in order that, through the interplay of fastening means and locking means, a virtually rigid plough body consisting of the two plough body basic elements, or a combination of both the two plough body basic elements with at least one plough body intermediate element, can be constructed. Since the plough body intermediate elements are installed between the plough body basic elements, although the guide mechanism has to be adapted, the support or guidance of the mining plough is always realized on both outer sides. A plurality of plough body intermediate elements can also be present, in which case the plough body intermediate elements are detachably connected or connectable one to another, and the plough body basic elements are detachably connected or connectable to the plough body intermediate elements by means of similar fastening means, so that underground only one type of fastening means has to be stocked for the construction of a mining plough of different structural height and only one type of fastening means has to be produced. 
     In a particularly preferred embodiment of a mining plough according to the invention, the fastening means consist of U-shaped clamps, which can be clamped by means of clamping screws against top and bottom sides on the plough body basic elements or the plough body intermediate elements and, in the assembled state, overlap the dividing plane between these, i.e. between the elements to be joined together. In the particularly preferred embodiment of corresponding fastening means, the clamps have clamping branches having wedge-shaped, mutually facing clamping surfaces, and the locking means are provided with wedge bevels for interaction with the clamping surfaces. When a pair of U-shaped clamps are clamped together, the plough body elements which are to be joined together can then, by means of the clamping surfaces and the wedge bevels, be clamped together perpendicular to the dividing plane with sufficient holding forces and, to this end, it is sufficient to respectively reduce the distance between the clamps. In a particularly advantageous embodiment, the fastening means can comprise a pair of clamps, the distance between which is variable by means of a clamping screw, whose shank, in the assembled state, is disposed in the dividing plane between the plough body elements to be connected. Such a mutual connection of two elements of a plough body can not only be provided in an easily accessible manner on the top sides and/or bottom sides of the plough body, but also offers the possibility, even in case of wear, of being able to tighten the fastening means with sufficient force and to successfully clamp together two elements which are to be connected. 
     A mining plough according to the invention preferably respectively consists of plough body basic elements, which have an outer side, on which the associated guide means interacting with the guide mechanisms are disposed, and an inner side, which forms the dividing plane and to which the other plough body basic element or a plough body intermediate element can be fastened. In the particularly preferred embodiment, the plough body has on each of the two outer sides a pair of guide means, namely a front guide means and a rear guide means, and, in addition, the guide means disposed on the opposite outer sides should be arranged in pairs one opposite the other. As a result of the even distribution of four guide means in all, namely two front guide means and two rear guide means, over the plough body on the outer sides, even if the loads upon the plough body should vary, a favorable support of the mining plough on the guide mechanisms, in particular an advantageous three-point support or three-point mounting of the plough body, can be achieved. Compared to the guidance principle known from the prior art, for example a portal-type guidance or a plough baseplate guidance, not only are the torques generated in the work effort kept low, but this also results, at the same time, in the plough body as a whole being able to be made narrower, less powerful and thus less weighty in design, which once again leads to a cheaper construction of the mining plough and to improved characteristics in working use. According to a particularly advantageous embodiment, the guide means on each outer side consist of slide runners, which are fastened to the plough body basic element movably, in particular pivotably about a bearing journal or pivot pin. The front and rear guide means can then be mutually aligned to be able to prevent the mining plough from jamming, even in the event of varying forces opposite to the motion of the mining plough. It is further advantageous if the plough body basic elements have on the outer side a extension, which extends rearwards, as an extension of the plough body basic element, beyond the dividing plane or the connecting region of a plough body basic element on the inner side, the, in the motional direction, rear one of the two guide means of each plough body basic element being fastened to the extension preferably such that it is pivotably movable. In addition, the fixture for the respective traction means can then also be configured on this extension in order to achieve not only a favorable force transmission, but also a compact construction of the plough body. 
     In order to still further improve the modus operandi of the plough system in working use, each plough body basic element can be provided with a mounting flange for a driving element for minerals. Such a driving element can optionally be fitted on one side in order, in the empty run to the evacuation section, to transport material in the pan downwards should individual rock fragments or mineral fragments or the like, despite a steep dip, be wedged or stuck in the pan. The mounting flange can be disposed, in particular, on a bottom side of the plough body basic element, preferably roughly in the middle, between both bearing points for the guide means, and/or can lie adjacent to the fixture for the traction means. 
     In order to work deposits, such as, for example, coal seams with a mining plough according to the invention, the mining plough, in a manner which is known per se, must be provided with machining tools, in particular ploughing tools. For this purpose, on each plough body basic element and, where present, on each plough body intermediate element, there is expediently configured at least one holding device for the detachable fastening of ploughing tools and/or for the detachable fastening of a tool strip for ploughing tools. The ploughing tools and the tool strip for the ploughing tools are here normally disposed on the front side of the plough body. In order to improve the operating characteristics of the mining plough according to the invention and to better match it to the anticipated loads in mining operation, the ploughing tools close to the inner sides of the plough body basic elements and/or the ploughing tools on the plough body intermediate elements can be set back relative to the ploughing tools on or close to the outer sides of the plough body basic elements. Particularly advantageous is an arrangement of ploughing tools on the front side, which arrangement runs, distributed over the height of the plough body, roughly in a W-shape. 
     In the working of coal seams in steep formation, the ploughing, in contrast to the working of coal seams in flat formation, is not realized by a reversing mining activity of the mining plough, but rather the extraction of coal takes place exclusively during the upward motion, counter to the dip, from a belt or evacuation section of an underground mining system to the head section, on which, in particular, the drives for the mining plough are also disposed. The rearward motion of the mining plough back to the evacuation section is realized as an empty run without mining activity, and during the empty run the mining plough is transported back into the starting position close to the evacuation section. The coal planed off from bottom to top in the mining run can be evacuated without a mechanically operated conveyor via slides, since, from a dip of about 25 gon (22.5 degrees), a sufficient tipping-over of the slide or slide channel is obtained, which causes extracted materials to slide down automatically to the evacuation section. In order to ensure a wear-free empty run, it is particularly advantageous if each plough body basic element is provided with a pivotable ploughing tool carrier for the reception of ploughing tools or a ploughing tool strip, all the ploughing tools assigned to a plough body basic element preferably being locked or lockable to the pivotable ploughing tool carrier. As a result of the pivotability of the ploughing tool carriers, the ploughing tools, during the empty run, can be pivoted virtually automatically into a position in which not only do the tool tips of the ploughing tools receive no contact with the material to be worked, but also, at the same time, the overall width of the plough body is less than in the mining run, so that the worked deposit offers, in principle, no resistance to the empty run. 
     The above objects are achieved in a plough system according to the invention by the fact that the mining plough has a separable plough body having two plough body basic elements, each plough body basic element being provided with a fixture for a separate traction means and with a guide means, and, in addition, the guide mechanism of the plough system having two guide bars, which are arranged at a distance apart and substantially at equal distance to the coal face and on which the plough body is forcibly guided with its guide means. The mining plough which is preferably usable on a plough system according to the invention has a plough body having the structure described further above. The arrangement of the guide mechanisms substantially in parallel and at equal distance to the coal face ensures a torque-free support of the plough body, since, in contrast to a baseplate plough, no unilateral, but rather a bilateral plough body support is realized. Each plough body basic element can have, in particular, a front and a rear guide means, the front and the rear guide means being fastened in a pivotably movable manner to each plough body basic element, and at least the rear guide means, in the assembled state, interacting with the guide bars with motional play in order that the plough body, in working use, receives a three-point support via three of the four guide means. The guide mechanism for a plough system according to the invention for the working of steeply stratified deposits can have, in particular, a roughly angular or L-shaped pan, the lower guide bar being fastened to a first branch disposed on the floor, and the upper guide bar being fastened by a cantilever arm to a second branch of the pan running angled-off from the lower branch. In this embodiment, the pan can at the same time also form the slide for evacuating the material extracted with the mining plough. 
     Further advantages and embodiments of a mining plough according to the invention and of a plough system according to the invention emerge from the following description of a preferred illustrative embodiment, shown in the drawing, of a plough system and a coal plough. 
     Further, these and other objects, aspects, features, developments and advantages of the invention of this application will become apparent to those skilled in the art upon a reading of the Detailed Description of Embodiments set forth below taken together with the drawings which will be described in the next section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail and illustrated in the accompanying drawings which form a part hereof and wherein: 
         FIG. 1  shows in perspective representation a detail from a plough system according to the invention with mining plough according to the invention; 
         FIG. 2  shows a side view of the plough system from  FIG. 1 , in a view of the top side of the mining plough, which top side faces the working face; 
         FIG. 3  shows the mining plough from  FIG. 1  in a view of the bottom side of the mining plough; 
         FIG. 4  shows an enlarged top view of one of the plough body basic elements of the mining plough, partially broken open; 
         FIG. 5  shows a sectional view along V-V in  FIG. 4 ; 
         FIG. 6  shows a sectional view along VI-VI in  FIG. 4 , partially broken open; 
         FIG. 7  shows, in an enlarged sectional view through the dividing plane between the plough body basic element and the intermediate element, the fastening elements in detail; 
         FIG. 8  shows in perspective representation a detailed view of a guide shoe according to the invention; 
         FIG. 9  shows a top view of a mining plough according to a second illustrative embodiment; 
         FIG. 10  shows the mining plough from  FIG. 9  in a view of the top side; and 
         FIG. 11  shows a mining plough from  FIG. 9 , consisting of plough body basic elements, in a view from the front. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring now to the drawings wherein the showings are for the purpose of illustrating preferred and alternative embodiments of the invention only and not for the purpose of limiting same, in  FIGS. 1 and 2 , a plough system for the extraction of coal in an underground, steeply stratified coal seam with a dip of, for example, more than 45 gon (40.5 degrees) is denoted in its entirety by the reference symbol  1 . The plough system  1  is placed in the steeply stratified deposit parallel to the coal face, hence at an angle to the horizontal, and consists of a multiplicity of trough pans  2  constructed identically to one another and comprising, inter alia, angular pans  3 , whereof the, in the figure, lower branch  4  rests on the floor, whilst the branch  5 , orientated approximately perpendicularly thereto, runs roughly parallel to the working face. On the offset-side rear sides of the branches  5  of the pans  3  there are disposed upper tubular guides  6 A and lower tubular guides  6 B, here arranged one above the other, through whose cavity return strands of the plough chains, represented only with the respective traction strand, can run. Via catchers, for example on the rear side of the branches  5  of the pans  3 , the whole of the plough system  1  can be moved, by means of shifting devices (not further represented), in line with the working progress at the coal face. Since the present application concerns itself neither with the design of supports for the plough system, nor with the shifting devices, these are not represented. 
     To the lower branch  4  of the pan  3  there is respectively fastened, close to the front end lying directly adjacent to the coal face, a lower guide bar  7 A, which in working use runs parallel to the coal face and on which the mining plough, denoted in its entirety by the reference symbol  10 , is guided by means of lower guide means, as will be further explained. Each trough pan  2  respectively has a lower guide bar element  7 A of this kind, and the guide bar elements  7 A of adjacent trough pans  2  can mutually engage or be interlocked in a suitable manner. The lower guide bars  7 A are preferably screwed, cast or welded onto the lower branch  4 . 
     In the shown illustrative embodiments, close to the upper end of the branch  5 , roughly rectangular brackets  8  are screwed, to which two supporting arms  9  are respectively welded such that they project forward in the direction of the working face, which supporting arms form the support elements for upper guide bars  7 B as the upper guide mechanism for the mining plough  10 . The upper guide bars  7 B lie, vertically offset, opposite the lower guide bars  7 A and extend, like the latter, over the entire length of the working face to be worked. As will be further explained, the mining plough  10  is guided by means of identical guide means both on the lower guide bars  7 A and on the upper guide bars  7 B. The guide bars  7 A,  7 B are arranged such that they lie opposite one another and have the same distance from the coal face in order that the mining plough with its plough body is transported substantially parallel to the coal face, is supported externally on both sides, and coal can be worked over the whole of the possible working height determined by the height of the plough system  1  and, in particular, of the plough body of the mining plough  10 , as well as of the uprising branch  5 . 
     For the movement of the mining plough  10  parallel to the coal face and along the guide bars  7 A,  7 B of the mining system  1 , in the longwall face two separate plough chains  11 A,  11 B are placed as traction means, both plough chains  11 A,  11 B consisting of horizontal and vertical chain links and being configured as continuous, revolving chains. The traction strand of each of both plough chains  11 A,  11 B runs within the slide surface or channel surface of the pans  3 , whilst the return strand of both plough chains  11 A,  11 B runs on the offset side of the pan  3  preferably in the represented tubular guides  6 A,  6 B, which form chain channels, and is returned to the evacuation section. The plough chain wheels, driven by means of suitable drive mechanisms, for moving the mining plough  10  to and fro in the longwall face by means of the plough chains, are preferably disposed exclusively in the so-called head section at the upper end of the longwall face, whilst the evacuation section, which, because of the steeply stratified coal seam, lies considerably lower down, contains only deflection pulleys for the two plough chains  11 A,  11 B. 
       FIGS. 1 and 2  already clearly show that the mining plough  10  has only a relatively small thickness and depth and is substantially wider than it is thick. Both guide bars  7 A,  7 B have a relatively large distance to the vertically running branch  5  of the pan  3  and the plough body fills the interspace only partially. Since the mining plough  10  is guided with its plough body on guide bars  7 A,  7 B lying one above the other, virtually no torques are generated in the work effort, which torques would have to be supported by the plough body or the guide bars. The plough body of the mining plough can therefore be given a relatively light construction, so that the mining plough  10 , because of reduced weight forces, can be transported to the head section with relatively low installed power. To the person skilled in the art, it will be readily apparent from  FIG. 1  that the mining plough  10  can only perform mining work in an upward direction of travel, whilst in downward travel it makes an empty run. Because of the tilt of the individual trough pans, however, the pans  3 , even without conveying elements, are able to evacuate the coal to the evacuation section purely on the basis of gravitational forces, since sliding generally sets in from a dip of around 24 gon (21.6 degrees). The movement to and fro of a relatively flat mining plough, which is guided parallel to the coal face on guide bars  7 A,  7 B arranged vertically one above the other and is moved by means of two separate ploughing chains  11 A,  11 B, constitutes an innovation for plough systems for steeply stratified coal seams, which plough systems are a precondition for the cost-effective working thereof. The inventive concept is also embodied, however, in the design and structure of the mining plough  10 , and its structure will now be described with additional reference to  FIGS. 3 to 8 . 
       FIGS. 1 to 3 , in particular, show that the mining plough  10  has a multipart plough body. In  FIGS. 1 to 3 , the plough body of the mining plough  10  consists of a lower plough body basic element  20 A, an upper plough body basic element  20 B and, in this case, two mutually identically configured plough body intermediate elements  30 . Only the plough body basic elements  20 A,  20 B are directly connected to the plough chain, in a tension-proof manner, by a suitable fastener means or fixture  21 , which fixture comprises a form-fitting receptacle for a plurality of chain links of the associated plough chain  11 A,  11 B. The plough body basic elements  20 A,  20 B are configured in mirror image of each other, and in the following description the respectively identical structural parts configured on both plough body structural elements  20 A,  20 B are denoted with the same reference symbol. Each plough body basic element  20 A,  20 B has a front guide element  23  and a rear guide element  22  in the working direction A, which guide elements here respectively consist of slide runners guided on the rectangular guide bars ( 7 A,  7 B,  FIGS. 1 ,  2 ). The front guide means  23  is fastened by a pivot pin  24  pivotably to the plough body basic element  20 A, the pivot pin  24  being able to be installed and removed from the bottom side  25  of the plough body basic element  20 A,  20 B. The slide runner forming the rear guide means  22  is pivotably connected, by a further pivot pin  27  installable from the top side  26  of the plough body basic elements  20 A,  20 B, to an extending extension  28  of the plough body basic element  20 . The extension  28  is integrally configured on the plough body basic element  20  and extends the plough body basic element  20 , respectively close to the outer side, by almost double the length to the rear, in order to achieve a sufficiently large distance between the front and rear guide means  23 ,  22 . In the shown illustrative embodiment, as clearly shown by  FIG. 3 , the detachable fixture  21  for the plough chains  11 A,  11 B is likewise respectively configured on the extension  28  close to the rear guide elements  22 . 
     Between a plough body intermediate element  30  and a plough body basic element  20  there is in each case a dividing plane T, at which the two elements  20 ,  30  of the plough body are detachably connected to each other by means of a fastening device  40 , the structure of which will be further explained. The extension  28  extends sufficiently far to the rear beyond this dividing plane T between two elements  20 ,  30  and forms the single extension of the plough body in order that the mining plough, despite the large distance between the front and rear guide means  23 ,  22 , can acquire, all in all, a reduced weight. Since, in  FIGS. 1 to 8 , the mining plough  10  consists of four elements in all, a further dividing plane is configured between two adjacent plough body intermediate elements  30 , a fastening of the adjacent plough body intermediate elements  30  being realized at this dividing plane, too, by means of identical fastening means  40 . The construction of the plough body of the mining plough  10  by two outer plough body basic elements  20  or  20 A,  20 B, which, in order to obtain a minimal working height, could also be directly connected to each other at the dividing plane by means of the fastening means, offers the advantage that, through the choice of a suitable number of intermediate elements, it is possible to attain almost any chosen working height by altering the effective width and/or height of the mining plough  10 . By using similar plough body intermediate elements, it is possible, with low stockholding of elements or multiple use of the same, to achieve a cost-effective and variable working of steeply stratified seams. 
       FIG. 4  shows an enlarged top view of a segment of the mining plough  10 , a segment of the plough body basic element  20 , with the ploughing tools  69  arranged on the front side, being represented on the left and a segment of a plough body intermediate element  30 , with the ploughing tools  79  fastened thereto, being represented in the right half. The dividing plane T between the plough body basic element  20  and the plough body intermediate element  30  runs perpendicularly to the height of the mining plough  10 . All ploughing tools  69  of the plough body basic element  20  are fastened to a tool carrier  61 , which is pivotably fastened to the plough body basic element  20  by a further pivot pin  62 . The pivotability of the tool carrier  61  serves in the empty run to pivot the tool tips of the ploughing tools  69  counter to the working direction into a position in which the tool tips of the ploughing tools  69  do not make contact with the coal face. The pivotal guidance of the tool carrier  61  on the plough body basic element  20  can be seen particularly clearly from the sectional view in  FIG. 5 . The entire bottom surface  63  of the tool carrier  61  rests on the plough body basic element  20  and the pivot pin  62  protrudes from the top of the plough body basic element  20 . For the supporting of forces perpendicular to the pin axis of the pivot pin  62 , the tool carrier  61  back-grips a guide web  70  on the plough body basic element  20  by means of a hook lug  64 . With a clip  65  detachably mounted on the free end of the pivot pin  62 , sufficient motional play is left to the tool carrier  61  to assume its two pivot end positions, according to the direction of travel of the plough. The forces transmitted via the ploughing tools  69  are preferably transferred to the plough body basic element  20  via the hook lug  64 . The pivot pin  24  for the front guide means  23  is anchored to the plough body basic element  20  beneath the tool carrier  61 , as can be seen particularly clearly from  FIG. 6 . 
     The detachable connection between a plough body basic element  20  and a further plough body basic element or a plough body intermediate element  30  is realized by means of fastening means  40 , the structure of which is now explained with reference to  FIG. 7 . Each fastening means  40  has, inter alia, a clamping screw  41  and a threaded shank, the axis of which lies, in the assembled state, within the dividing plane T and extends into locking recesses  68 ,  78  on the top side  27  and the bottom side  26 . Each fastening means  40  additionally consists of two mutually identically configured clamps  42 , each of which is of approximately U-shaped configuration and has in the center a passage for the shank of the clamping screw  41 . For the clamping or wedging together of two plough body basic elements  20 , or of one plough body basic element  20  with a plough body intermediate element  30 , each clamp has two clamping branches  43 , which are provided on the mutually facing inner faces with clamping surfaces  44  which run in the shape of a wedge, the distance between the clamping surfaces  44  rising with increasing distance from the base of the clamps  42 . These clamping surfaces  44  interact with wedge bevels  29  on the plough body basic element  20  and wedge bevels  39  plough body intermediate element  30 . The wedge bevels  29 ,  39  lie respectively, facing away from the dividing plane T, in the region of the locking recesses  68  and  78  on the top sides  27 ,  37  and bottom sides  26 ,  36  of the plough body basic elements  20  or plough body intermediate elements  30 . Adequate dimensioning of the depth of the locking recesses  68 ,  78  and the length of the clamping surfaces  44 , as well as of the wedge bevels  29 ,  39 , allows a relatively high clamping force to be applied transversely to the dividing plane T by tightening of at least one nut  47 . In the shown illustrative embodiment, the clamping screw  41  for each clamp  42  is provided with a separate nut  47 , so that the clamping of the fastening means  40  can be realized, according to accessibility, both from above and from below, or else only from one of the two sides. 
     The arrangement of the ploughing tools  69  on the plough body basic elements  20  and of the ploughing tools  79  on the plough body intermediate elements  30  is realized in such a way that all the ploughing tools  69 ,  79  are arranged in a roughly W-shaped pattern overall. Adjacent ploughing tools therefore impact in different planes on the mineral to be worked, so that the loosening force of each individual ploughing tool  69  or is able to develop particularly well. The respectively outermost ploughing tools  69  preferably project further in the working direction than all the other ploughing tools  69 ,  79 , as can clearly be seen from  FIG. 2 . The ploughing tools arranged in the middle of the whole of the plough body in turn stand further forward than all other ploughing tools on the plough body intermediate elements. Behind the ploughing tools, indents or flattenings are configured in the plough body in order to direct into the pan the mineral extracted at the coal face. 
     The four guide means  23 ,  22  in all, respectively two guide means  23 ,  22  being arranged on the lower plough body basic element  20 A and two further guide means  23 ,  22  on the upper plough body basic element  20 B, lead in working use, when the mining plough  10  is transported in the working direction A, to the two front guide means  23  and only one of the rear guide means  22  being laden with the supporting forces, according to the resistance of the worked mineral. One of the two rear guide means  22  hence does not for the present come into direct contact with the associated guide bar  7 A or  7 B, since the distance between the pivot axes of the pivot pins  27  of the rear guide means  22  is preferably slightly less than the distance between the pivot axes of the pivot pins  24 . The distance can also, however, be equal. The pivotability of each slide runner as the guide means  23 ,  22  ensures at all times that the respective slide runner optimally matches the course of the guide bar  7 A or  7 B. 
     The mining plough  10  is provided with a driving element  90 , which, as can be seen particularly clearly from  FIGS. 1 and 3 , is configured as a tapered driving block and is pivotably fastened, preferably by a pivot pin, to a fixing eyelet  92 , which forms the mounting flange for the driving block  90 . The mounting flange  92  lies roughly midway between the pivot pin  24  for the front guide means  23  and the pivot pin  27  for the rear guide means  22 . Each plough body basic element  20 A,  20 B is provided with a fixing eyelet  92 . 
       FIG. 8  shows a preferred illustrative embodiment of a slide runner  85  as the guide means  23  or  22 . For interaction with the roughly rectangular cross section of the guide bars ( 7 A,  7 B,  FIG. 1 ), the slide runner  85  has a rectangular slotted indent  86 , which extends over the entire length of the slide runner  85 . The guide slot  86  is delimited on both sides by strong guide branches  87 , which merge integrally into a base branch  88  that has on its rear side a hinge eyelet  89  for the passage of the pivot pin  24 ,  27 . The hinge eyelet  89  is configured in the region of a middle web  84 , which has roughly the width of the guide recess ( 51 ,  FIGS. 5 and 52 ,  FIG. 6 ) on the plough body basic element  20  and, in terms of thickness, is markedly reduced relative to the total thickness of the slide runner  85 . As a result of the mutually offset surfaces, shown, by way of example, by  FIGS. 5 and 6 , the slide runner  85  can be guided into the guide recesses  51  and  52  in the plough body basic element  20  in such a way that it can pivot only perpendicularly to the pivot axis of the associated pivot pin and transverse forces can be absorbed by virtue of a form fit. 
       FIGS. 9 and 10  show further illustrative embodiments of a mining plough  110 . As in the previous illustrative embodiment, the mining plough  110  is guided on two mutually opposing guide bars of a plough system, as this is represented in  FIG. 1 . The plough body of the mining plough  110  comprises two plough body basic elements  20 A,  20 B, the structure of which is identical to that in the previous illustrative embodiment, so that reference is made to the description given there. Each plough body basic element  20 A,  20 B is once again provided with rear guide means  22  and front guide means  23 , which are fastened pivotably to the plough body basic element  20 A,  20 B. The ploughing tools  69  of both plough body basic elements  20 A,  20 B are once again detachably fastened to a tool carrier  61 , which can pivot relative to the plough body basic element  20 A or  20 B about a pivot pin  62 . The sole difference between the illustrative embodiments consists in the design of the plough body intermediate element  130 , which here consists of a single element, which is respectively externally connected by one end to the plough body basic element  20 A and by the other end to the plough body basic element  20 B by means of the same fastening means  40 , as these have been described further above with reference to the first illustrative embodiment. To the plough body intermediate element  130  there is respectively fastened an inner set of ploughing tools  179 A and an outer set of ploughing tools  179 B, in the shown illustrative embodiment five of the ploughing tools respectively being fastened to a common tool strip  195 . For the replacement of the ploughing tools, only the tool strips  195  need to be removed by the unscrewing of two fastening screws  196  and exchanged for others.  FIG. 10  illustrates particularly clearly how flat the mining plough according to the invention  110  can be built overall so as nevertheless to work the coal face over a height here extending to roughly six times the depth. 
       FIG. 11  shows yet further illustrative embodiments of a mining plough  210 . As in the previous illustrative embodiments, the mining plough  210  is also guided on two mutually opposing guide bars of a plough system, as this is represented in  FIG. 1 . The plough body of the mining plough  210  comprises or consists solely of two plough body basic elements  20 A,  20 B, the structure of which is identical to that in the first illustrative embodiment, so that reference is made to the description given there. Each plough body basic element  20 A,  20 B is provided with the front guide means  23  discernible in front view, as well as with rear guide means, which are all pivotably fastened to the plough body basic element  20 A,  20 B. The ploughing tools  69  of both plough body basic elements  20 A,  20 B are once again detachably fastened to a tool carrier  61 , which can pivot relative to the plough body basic element  20 A and  20 B about a, in this view, non-discernible pivot pin. The two plough body basic elements  20 A,  20 B are connected with the same fastening means  40  to a plough body of minimal width and thus minimal working height, the depth of the relatively narrowly constructed mining plough amounting to roughly half the working height. A driving block can be mounted on one of the fixing eyelets  92 . 
     For the person skilled in the art, numerous modifications emerge from the preceding description, which modifications shall fall within the range of protection of the appended claims. In a further, non-represented embodiment, a mining plough guided on both sides on guide bars or the like lying one above the other could also consist of a one-piece plough body element. All the advantages of being able to convert the same plough body to different working heights would then, however, be lost. 
     Further, while considerable emphasis has been placed on the preferred embodiments of the invention illustrated and described herein, it will be appreciated that other embodiments, and equivalences thereof, can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. Furthermore, the embodiments described above can be combined to form yet other embodiments of the invention of this application. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.