Abstract:
The present disclosure relates to a scraper for chain scraper conveyors, particularly twin chain scraper conveyors. The scraper may comprise a one-piece scraper bridge including two side scraper wings connected by a head web, a retaining bracket insertable from an underneath side of the scraper bridge into an insert recess, and a locking device. The retaining bracket may be insertable for detachably locking the scraper on a chain link of a scraper chain. The retaining bracket may engage with grooves on either side of the insert recess in an assembled state. The scraper may further include a locking device for securing the assembly state of the retaining bracket in the insert recess, wherein the retaining bracket may be displaceable in the associated insert recess parallel to the head web on one of the scraper wings into a locking position and having at least one retaining cam.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a National Stage of International Patent Application No. PCT/EP2013/001524, filed May 23, 2013, which claims priority to foreign German Patent Application No. 20 2012 102 111.0, filed Jun. 8, 2012, the contents of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to scrapers for chain scraper conveyors, more particularly for twin scraper chain conveyors, and to a scraper bridge for such a scraper. 
       BACKGROUND 
       [0003]    Scrapers of generic kind for chain belts of twin inboard chain scraper conveyors are used particularly in underground mining operations and are subjected to high mechanical stress, since they have to convey the entire highly abrasive conveyor material in the conveying belt side of the scraper chain conveyor. 
         [0004]    For example, DE 102 25 341 C1 discloses a scraper fixed on chain links of scraper chains whose horizontal and vertical chain links each consist of oval ring eyelet members with round chain bow ends. Fixing the scraper on the horizontal chain links of these link chains is carried out by means of a retaining or securing bracket which runs in one piece between the two insides of the scraper wings of the scraper bridge, clamps the horizontal chain links from below against the underneath of the head web of the scraper bridge and fits laterally by its bracket ends in grooves on the insides of the scraper wings. Mounting the retaining bracket is undertaken by vertically sliding in from underneath, and securing the bracket on the head web against release is carried out by means of spring pins which can be inserted in through bores, engage through the pivots which are formed integral on the upper side of the bracket and engage in corresponding bolt recesses in the head web. 
         [0005]    From DE 195 11 043 C1 it is known that the horizontal chain links clamped on the scraper are exposed to increased wear if they are not clamped sufficiently firmly and permanently between the bracket and the scraper body. In order to counteract any loosening of the chain links on the scraper body during the moving conveyor operation, the chain brackets and the underneath of the scraper body are curved convex relative to the longitudinal axis of the scraper in order during assembly to exert a defined assembly force on the inner and outer arms of the chain links. This assembly force is introduced into the bracket via nuts and threaded bolts. The threaded bolts are formed integral on the upper side of the chain bracket and engage through bores in the scraper body. The nuts which are countersunk in large surface area sockets on the top side of the scraper body are screwed up tight by generating the assembly and clamping force thereon. 
         [0006]    During operation of the scrapers with screw connections between the retaining brackets and scraper body, cracks appear in part in the scraper body particularly in the area of the recesses particularly when they are used in high performance conveyors. The cause of this is inter alia also the reduction in the cross-sectional size of the head web of the scraper bridge as a result of the recesses for the nuts. With the scraper known from DE 102 25 341 C1 this is indeed avoided by the comparatively strong pivots, but storing these retaining brackets as spare parts is however made difficult by the pivots, the material and manufacturing costs for both the brackets and the scraper bridge are high and in order to dismantle the retaining bracket it is necessary in order to prevent canting to act on the two pivots as far as possible simultaneously e.g. with a hammer tool. 
         [0007]    The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems. 
       SUMMARY OF THE DISCLOSURE 
       [0008]    According to an aspect of the present disclosure, a scraper for chain scraper conveyors, more particularly twin chain scraper conveyors, may comprise a one-piece scraper bridge including two side scraper wings connected by a head web. The scraper bridge may further include a retaining bracket being insertable from an underneath side of the scraper bridge into an insert recess for detachably locking the scraper on a chain link of a scraper chain, and form-fittingly engaging with grooves on either side of the insert recess in an assembled state. The grooves may be opened towards the underneath side of the scraper bridge. The scraper bridge may further include a locking device for securing the assembly state of the retaining bracket in the insert recess. The retaining bracket may be displaceable in the associated insert recess parallel to the head web on one of the scraper wings into a locking position and having at least one retaining cam, which in the locking position engages in a groove section formed with an under-cut section of the groove. 
         [0009]    According to another aspect of the present disclosure, a scraper bridge for a scraper of a chain scraper conveyor, particularly for a scraper according to the present disclosure, may comprise two lateral wings, a head web connecting the lateral wings, an insert recess formed underneath the head web for a retaining bracket which can be inserted from an underneath side of the scraper bridge for detachably locking the scraper on a chain link of a scraper chain, and grooves opening to the underneath side of the scraper bridge on each side of the insert recess for supporting the retaining bracket with positive locking engagement. The grooves may have a groove section formed with an under-cut section into which a retaining cam on the retaining bracket can be pushed by a transverse displacement. 
         [0010]    According to another aspect of the present disclosure, a retaining bracket for a scraper of a chain scraper conveyor, particularly for a scraper according to the present disclosure, may comprise a bracket body insertable into an insert recess on a scraper bridge. The bracket body may be formed underneath a head web of the scraper bridge and having grooves opening towards the underneath of the scraper bridge on each side of the insert recess for supporting the retaining bracket with positive locking engagement. The bracket body may be provided integral with at least two retaining cams spaced from one another for engaging behind groove sections formed with under-cut section in the grooves in the scraper body. 
         [0011]    Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows a perspective view of a scraper according to a first embodiment with an inserted chain section, a fitted retaining bracket and inserted filler member looking onto the underneath of the scraper; 
           [0013]      FIG. 2  shows a side view of the scraper bridge of  FIG. 1  with an insert recess shown in dotted lines; 
           [0014]      FIG. 3  shows a perspective view of the scraper bridge of  FIG. 1  looking onto the insert recesses; 
           [0015]      FIG. 4  shows a vertical section through the scraper wing of the scraper according to  FIG. 1  in the area of the under-cut groove and the retaining cam on the retaining bracket; 
           [0016]      FIG. 5  shows a perspective view of the retaining bracket used in the scraper according to  FIG. 1 ; 
           [0017]      FIG. 6  shows a scraper according to a second embodiment in a longitudinal sectional view; 
           [0018]      FIG. 7  shows the scraper bridge of the scraper according to  FIG. 6  in side view with the insert recess indicted in dotted lines; 
           [0019]      FIG. 8  shows the scraper bridge of the scraper according to  FIG. 6  in a perspective view onto the underneath with the separate insert recesses; 
           [0020]      FIG. 9  shows a retaining bracket according to a second embodiment for the scraper according to  FIGS. 1 to 6  in a perspective view; and 
           [0021]      FIG. 10  shows a scraper according to a third embodiment in a perspective view onto the underneath of the scraper. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the drawings are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of patent protection. Rather, the scope of patent protection shall be defined by the appended claims. 
         [0023]    In  FIG. 1  a scraper according to a first embodiment of the present disclosure is denoted by the reference numeral  10  and is designed for connecting to the two chain strings running parallel to one another of a twin inboard chain of a twin inboard chain scraper conveyor. The scraper  10  consists of a strong scraper bridge  1 , preferably made as a cast or forged part, which has at each of its two opposite ends a scraper wing  2  which are connected to one another by a head web  3  as the center part of the scraper bridge  1 . 
         [0024]    In the illustration of  FIG. 1 , the scraper  10  is shown looking onto the underneath of the scraper bridge  1 , although when in operation the surface which lies at the top in  FIG. 1  actually forms the underneath  16  of the scraper wings  2  or the scraper bridge  1 . The scraper  10  may glide in the conveying belt side of a chain scraper conveyor, also known as an armored face conveyor, over its conveyor base, in order with its end side lying at the front in the running direction to push forward the material such as, for example, coal which is to be conveyed. 
         [0025]    In a chain scraper conveyor (not shown) corresponding scrapers  10  come into use at intervals of mostly about 0.8 m-2 m and are for this detachably attached to the horizontal chain links  4  of the individual chain strands  5 A of the scraper chain  5 . As a horizontal guide, the scrapers  10  engage using the outer profiled end zones  7  of the scraper wings  2  into correspondingly profiled side profiles in the conveying strand or return strand of the scraper chain conveyor and the scraper wings  2  widen out towards the end zones  7  in order to obtain an improved conveying behaviour for the material to be conveyed in the conveying strand. 
         [0026]    The connection of the scraper bridge  1  of the scraper  10  to the chain strands  5 A of the twin chain  5  takes place in the first embodiment through two spaced insert recesses  8  which are open to the underneath  16  of the scraper bridge  1  and are here separated from one another by an intermediate web  9 . Each horizontal chain link  4  of each chain strand  5 A is inserted in an associated insert recess  8  in order to achieve the connection between the twin chain  5  on the one hand and the scraper  10  on the other. 
         [0027]    For each insert recess  8  there is in the case of the scraper  10  according to  FIG. 1  a separate retaining bracket  20  which can be inserted from underneath  3  into the insert recess  8 .  FIG. 1  shows the assembly states in which the two retaining brackets  20  are located in a locking position. In this locking position the horizontal chain link  4  is locked or clamped in the relevant insert recess  8  between the underneath of the head web  3  on the one hand and the upper side of the relevant retaining bracket  20  on the other. 
         [0028]    As can be clearly seen from  FIG. 1 , each retaining bracket  20  engages in a groove  11  which extends out from the underneath  16  of the scraper bridge  1  to the top web  3 . The retaining bracket  20  is enclosed in the running direction of the scraper  10  in part by wall parts of the scraper bridge  1 . With the scraper  10  according to the present disclosure, the retaining brackets  20  can however not be pushed by a purely vertical movement into the grooves  11  in order to reach the locked position shown in  FIG. 1 . Rather the fitting of each retaining bracket  20  in the associated groove  11  of the relevant insert recess  8  is carried out by a combined movement, namely a lowering movement into the groove and then a transverse displacement of each retaining bracket  20  in the associated groove  11  onto the adjoining scraper wing  2 . 
         [0029]    An assembly and dismantling of the retaining brackets  20  in the case of the scraper according to  FIG. 1  is only possible when the filler member  30  located between the two retaining brackets  20  is dismantled and a groove extension  12 , which here connects the two grooves  11  together and forms an assembly opening for the retaining brackets  20  and is closed by means of the filler member for the operating use, is open. With the first embodiment the groove extension  12  which is arranged in the centre web  9  connects the relevant grooves  11  of the associated two separate insert recesses  8  for the two separate but identically designed retaining brackets  20 . 
         [0030]      FIG. 5  shows a retaining bracket  20  in detail, wherein special features of the retaining bracket  20  are first explained. The retaining bracket  20  has a relatively elongated bracket body  21  whose base surface forms a cross with two long arms and two short arms. The short arms are arranged centrally between the two bracket ends  22  of the long arms of the bracket body and project as bearing noses  23  for the chain links of a chain strand sideways over the end sides of the bracket body  21 . 
         [0031]    In order to form functional bearing noses  23 , the front sides of the short arms are provided in part with a curvature or a curved bearing surface  24  which can be adjoined in the assembly state of a scraper on a scraper chain, as shown in  FIG. 1 , by the bow ends of the vertical chain links  6  which lie adjoining the scraper. The bracket body  21  of the retaining bracket  20  has zones of different width. The width in the area of the bracket webs  27  underneath the retaining cams  25  and in the intermediate section  29  in which the positioning web is not formed, is hereby the same. The bracket body  20  has the maximum width in the area of the bearing noses  23  and the curved bearing faces  24 . The width measurement of the retaining bracket  20  in the area of the bearing noses  23  is hereby preferably smaller than the width of the scraper bridge in the area of the head web  3 . 
         [0032]    A special feature of the retaining bracket  20  consists in the fact that this is provided, in the illustrated embodiment each directly adjoining the bracket body ends  22 , with retaining cams  25  which project on both sides beyond the end faces of the bracket body  21 , wherein the bracket body  21  has a T-shaped cross-section in the area of the retaining cams  25  and the retaining cam  25  extends roughly only over half the height of each retaining bracket  20 . As a result of this special configuration of the retaining bracket with in this case several retaining cams, a transverse displacement of the retaining bracket  20  inside the insert recess  8  is required for the assembly and locking of the retaining bracket  20  in the insert recess on the scraper bridge. The retaining cams  25  each lie spaced from the flat underneath  26  of the bracket body  21 . In the assembly state of the retaining bracket  20  however the retaining cams  25  each engage behind a groove section  13  of the groove  11  formed with an under-cut section either side of the insert recess. 
         [0033]    This is particularly easy to see in  FIG. 4  which shows a vertical section through a scraper  10  parallel to the running direction of the scraper. A widened under-cut groove section  13  of the groove  11  is located on either side of an insert recess. As a result of the positive-locking engagement of the retaining cams  25  in these under-cut groove sections  13 , as shown in  FIG. 4 , the retaining bracket  20  is held in its locking position in the vertical direction in the insert recess. Each retaining cam  25  forms an under-cut anchor for fixing the retaining bracket  20  in the groove  11 . The retaining cam  25  only comes free from the under-cut groove section  13  through a transverse displacement of the retaining bracket  20  inside the insert recess  8 . 
         [0034]    The structural design and shaping of the insert recess  8  as well as the associated grooves  11  can be seen particularly clearly from the perspective view onto the underneath of the scraper wing  1  in  FIG. 3 . Each insert recess  8  comprises a groove  11  located on the inside of a scraper wing  2 , and a groove  11  located in the centre web  9 . Each groove  11  has on the base  16  of the scraper wing  1  a narrower opening cross-section than close to the bottom  11 A of the groove. This rectangular groove extension designed as an under-cut section and preferably milled with a groove cutter provides for an under-cut groove section  13  of the grooves  11  in the area of the centre web  9  as well as in the area of the scraper wing  2 . 
         [0035]    The groove extension directly adjoins the groove bottom  11 A of the groove  11 . Matching the T-shaped or rectangular geometrical shape of the retaining cams  25  on the retaining brackets  20 , the groove sections  13  which provide for the under-cut section also have a T-shaped or rectangular cross-section over the entire groove length up to each relevant side outer groove end, so that the retaining cams can be pushed correspondingly far into the under-cut groove sections  13  until the relevant inner lying bracket end of a retaining bracket then lies flush with the side borders  12 ′ of the groove extension  12  in the centre web  9 . The terms outside and inside refer here to the longitudinal extension of the scraper bridge on which the scraper wings are arranged on the outside and the centre web lies on the inside. 
         [0036]    The internal width of the groove  11  close to the groove bottom  11 A, thus in the area of the widened groove sections  13  providing for the under-cut section, must be greater than the width of the retaining bracket between the end sides of the retaining cams  25  ( FIG. 3 ). The same applies for the width of the groove extension  12  in the centre web  9 . The groove  11  has in the area of the widened groove section  13  providing for the under-cut section substantially the same width as the groove extension  12  in the centre web  9 . 
         [0037]    In order to fit a retaining bracket  20 , it must be fitted, when the filler member  30  is dismantled, from below against the scraper bridge  1  so that the one pair of retaining cams  25  at one end  22  of the retaining bracket  20  is located inside the groove extension  12  which forms the “assembly opening”, whilst the other pair of retaining cams  25  is located inside the actual insert recess  8  between the grooves. 
         [0038]    In this insert position, which is not shown for the first embodiment according to  FIGS. 1 to 5 , namely only in this position, the retaining bracket  20  can then be lowered vertically downwards down to the groove bottom  11 A of the grooves  11  until its underneath  26  lies flush with the underneath  16  of the scraper  1 . Only then can the transverse displacement of the retaining bracket up to the adjoining scraper wing  2  take place wherein this transverse displacement takes place parallel to the longitudinal extension of the scraper bridge  1 , and correspondingly transversely to the running direction of the scraper chain  5  or scraper  1  in the operating use of a chain scraper conveyor. During the transverse displacement the retaining cams  25  lying at the front then engage in the relevant widened groove section  13  of the groove  11  in the area of the scraper wing  2  and the correspondingly rear or inwardly lying retaining cams  25  engage in the under-cut or widened section  13  of the groove  11  in the area of the centre web  9  of the scraper bridge  1 , whereby a retaining bracket  20  is secured in the vertical direction through the interaction of the under-cut groove sections  13  and the retaining cams  25  and is also at the same time secured with positive locking parallel to the conveyor direction, since the bracket body  21  of the retaining bracket  20  engages with the relevant bracket web  27  underneath the retaining cam  25  into the narrower area of the groove  11 . 
         [0039]    After a first retaining bracket  20  is placed in the aforesaid way against the groove extension  12  and shifted into its locking position, as shown in  FIG. 1 , the second retaining bracket  20  can then be mounted accordingly. For this the second retaining bracket with the filler member  30  removed is brought into an assembly position in which the one inner retaining cams  25  are located in the area of the groove extension  12  and the other outer retaining cams  25  are located in the area of the insert recess  8 . In this position first the lowering takes place downwards to the groove bottom ( 11 A,  FIG. 3 ) and then, opposite to the transverse movement of the first retaining bracket  20 , a transverse displacement takes place of the second retaining bracket  20  to the other scraper wing  2 , so that then the two retaining brackets  20  reach the locking position illustrated in  FIG. 1 . 
         [0040]    As soon as the two retaining brackets  20  are pushed into their locking position, the filler member  30 , which can consist of a rectangular block, is pushed in a vertical movement into the groove extension  12  and is then secured against falling out from the groove extension  12  by means of, for example, a spring pin  31 . Each retaining bracket  20  hereby engages on either side of the insert recess  8  with positive connection in a section of the groove  11  and is secured against falling out on either side of the insert recess  8  via an under-cut section. Again, during operation, no noticeable forces act on the filler member  30 . 
         [0041]    All the forces in the direction of movement are rather introduced into the retaining bracket  20  from the vertical chain links  6  on the one side via the bearing noses  23  and are introduced via the retaining cams  25  and in particular the bracket webs  27  into the scraper body  2 , and on the other side are also introduced directly into the scraper bridge  1 . As shown clearly in  FIGS. 2 and 3 , each insert recess  8  has chain link beds  17  formed on the underneath of the head web  3  for the longitudinal arms of the horizontal chain links. 
         [0042]    In order to improve the force transfer, a bearing nose  18  which projects slightly over the end sides of the head web  3  is formed between the chain link beds  17 , and the upper area of the bow ends of the vertical chain links ( 6 ,  FIG. 1 ) can bear against the nose. In the assembled state of a retaining bracket  20  on the scraper bridge  1  the curvatures  24  of the bearing noses  23  on the retaining brackets  20  lie directly underneath the likewise arcuate curved bearing noses  18  of the scraper bridge  1 , wherein the bearing nose  18  fits likewise in the eyelet-type centre opening of the horizontal chain link  4  which is enclosed loose in the insert recess  8 . 
         [0043]    The retaining bracket  20  according to  FIGS. 1 and 5  has additionally still between the right-hand side pair in  FIG. 5  of retaining cams  25  and the centrally positioned bearing noses  23  on either side, a positioning web  28  which is formed integral on the bracket body  21 . The positioning web  28  defines the displacement path of each retaining bracket  20  to the outside, since the head face  28 ′ of the positioning web  28  projects slightly beyond the web section  27  underneath the retaining cams  25 . 
         [0044]    The retaining bracket  20  according to  FIG. 5  can therefore fit on each insert recess  8  only in a predominant direction, for the positioning web  28  must during assembly of the retaining bracket  20  lie inside the insert recess  8  underneath the chain link beds  17  and between the grooves  11 , whilst the retaining cams  25  are inserted at the opposite bracket end  22  into the groove extension  12 . Tolerances of the groove  11  and the dimensions of the insert recess  8  can be compensated via the positioning web  28 , since the distance between the top side  28 ′ of the positioning web  28  and the bracket end  22 , on the left in  FIG. 5 , can be determined relatively exactly. 
         [0045]    In order to facilitate dismantling of the filler member  30  after removing the tension sleeve  31 , the head web  3  is provided from its upper side with a dismantling groove  19  opening into the groove extension  12  and into which a mandrel or the like can be driven to drive out the filler member. 
         [0046]      FIGS. 6 to 9  show a second embodiment of a scraper  100  according to the present disclosure as well as an associated retaining bracket  120 . As with the previous embodiment the scraper  100  consists mainly of a strong forged or cast scraper bridge  101  with lateral scraper wings  102  formed integrally on a centre head web  103  wherein excavated material is moved inside the conveyor channel of a chain scraper conveyor with the end sides of the scraper wings  102  and the end side of the head web  103 . As with the previous embodiment, also here two separate insert recesses  108  are formed underneath the scraper bridge  101  each for receiving a separate retaining bracket  120 , as shown in  FIG. 6 . 
         [0047]    As with the previous embodiment, a centre web  109  is located between the insides of the scraper wings  102 , with the underneath side  109 ′ of the centre web aligned flush with the underneath side  116  on the scraper wings  102  and thus the underneath side of the scraper bridge  101 .  FIG. 6  shows the retaining bracket  120  in the locking position in which the arms of the horizontal chain links  104  are gripped by the upper side of the retaining bracket  120  and are in this way secured completely inside the arm beds  117  against falling down and out. 
         [0048]    Also here a downwardly projecting bearing web  118  extends on the scraper bridge  101  between the arm beds  117 , the two end sides of the bearing web being provided with bearing recesses  118 ′ for the bow ends of the vertical chain links. In the assembly state, the bearing web  118  engages in the eyelet opening of the horizontal chain links. On each side of each insert recess  108  there is a groove  111  which is formed open to the underneath  116  and in particular  FIG. 8  shows clearly that each groove  111  adjoining the groove bottom  111 A has a T-shaped groove section  113  which provides for an under-cut section and which serves for the positive locking engagement of the retaining bracket  120  in the locking position. 
         [0049]    Deviating from the previous embodiment, here the grooves  111  for the left insert recess  108  and the grooves  111  for the right insert recess  108  are not connected to one another, but each groove  111  is assigned a separate groove extension  112  as the assembly opening for the retaining bracket  120 . The groove extension  112  each time adjoins the extended groove section  113  of that groove  111  which is formed on the insides of the scraper wings  102 . 
         [0050]    The width of the groove extension  112  is adapted so that the retaining bracket  120  shown in detail in  FIG. 9 , and which here has two planes of symmetry, namely on the one hand along the elongated bracket body  121  and furthermore centrally between the two bracket ends  122 , with the retaining cams  125  formed adjoining the bracket ends  122  and which project each side over the narrow and substantially bar-shaped central bracket body  121 , can be lowered over the bracket extension  112  on one side and the insert recess  108  on the other side in the groove before the retaining bracket  120  is displaced by transverse displacement into its locking position in which the retaining cams on the retaining bracket  120  engage behind the grooves  111 . 
         [0051]    Also here the retaining bracket  120  must for assembly first be placed against the insert recesses  108  so that the one pair of retaining cams  125  is inserted in the groove extension  112  and the other pair of retaining cams  125  is located at the other bracket end  122  inside the insert recess  108 . Only in this assembly position, the bracket may be moved downwards until its upper side  121 ′, which in  FIG. 9  forms the rear side, bears against the groove bottom  111 A of the relevant groove  111 . Each retaining bracket  120  is then moved from this position through a transverse displacement into its locking position, as shown in  FIG. 6 , wherein through the transverse displacement the retaining cams  125  are each pushed into the under-cut groove sections  113  and hereby lock the retaining bracket  120  with positive engagement in the vertical direction. 
         [0052]    Since the groove extension  112  is located laterally on the outside in relation to the associated insert recess  108 , the displacement movement in the case of the scraper  100  takes place up to the centre web  109  and as soon as the locking position of the retaining bracket  120  is reached, a filler member  130  is pushed in from below into the groove extension  112 , thereby preventing as a result of its geometrical shape a return displacement of the retaining bracket  120 . 
         [0053]    Since the filler member  130  is again not subjected to any stress or load, a simple spring pin  131  which engages through a central bore  132  in the filler member  130  as well as through mutually aligned bores  140  in the side walls defining the groove extension  112 , is thereby sufficient for securely locking the filler member. To dismantle each filler member  130 , the scraper bridge  101  is provided for each groove extension  112  with a separate dismantling bore  119  into which a dismantling mandrel or the like can be driven from the top side of the scraper bridge  101  in order to knock down and out the filler member  130  when the spring pin  131  is dismantled. 
         [0054]    The retaining bracket  120  also has centrally between the pairs of retaining cams  125  a transverse web  123  which projects either side beyond the bracket body  121  and is provided on its upper side with curved bearing noses  124  for the bow ends of the vertical chain links. In the locking position the transverse webs  123  with the bearing noses  124  on the retaining bracket  120  lie directly opposite the bearing webs  118  with the bearing recesses  118 ′ on the underneath of the scraper bridge  101 . 
         [0055]    The retaining bracket  120  shown in  FIG. 9  has no predominant direction and no positioning stop. The retaining bracket  120  can hereby have a slightly larger play than the retaining bracket with the positioning stop as with the previous embodiment. The retaining bracket  120  illustrated in  FIG. 9  may however also be used in the case of the embodiment of a scraper according to  FIGS. 1 to 4 , or the retaining bracket according to  FIG. 5  may also be used in the case of the embodiment of a scraper bridge according to  FIGS. 6 to 8 . 
         [0056]      FIG. 10  shows a third embodiment of a scraper  200  according to the invention for mounting on horizontal chain links of a twin chain of a chain scraper conveyor. Also here the one-piece scraper bridge  201  has two lateral scraper wings  202  which are connected to one another by way of a head web  203 . Between the insides of the scraper wings  202  there is however only one single insert recess  208  for holding a single retaining bracket  220  whose length is suitably adapted to be able to engage underneath the entire width span of the insert recess  208  and to be able to engage by its one bracket end  222  in a groove  211  in the one scraper wing  202  and by its other bracket end  222  in a groove  211  on the inside of the opposite scraper wing  202 . 
         [0057]    The retaining bracket  220  has in turn adjoining the bracket ends  222  retaining cams  225  protruding on each side whereby the relevant bracket ends  222  have a T-shaped cross-section extending over a sufficient partial length. 
         [0058]    Each groove  211  has, as with the previous embodiments, one downwardly off-set widened groove section  213  which provides for an under-cut section of the groove  211  on the insides of the scraper wings  202  and into which the retaining cams  225  engage in the locking position of the retaining bracket  220 .  FIG. 10  shows however not the locking position but the assembly position of the retaining bracket  220 , for in this position the retaining cams  225  at the right bracket end  222  of the retaining bracket  220  engage in a groove extension  212  formed on the underneath side of the right scraper wing  202 , whilst the other retaining cams  225  as a result of the assembly position are located in the insert recess  208 . 
         [0059]    As soon as the retaining bracket  220  is introduced into the groove extension  211  or the insert recess  208  down to the groove bottom, the retaining bracket  220  may be moved transversely so that the retaining cams  225  engage in the under-groove sections  213  of the grooves  211  and secure the retaining bracket firmly in the vertical direction. It is then only necessary, as with the previous embodiments to insert a filler member (not shown) into the groove extension  212  which then prevents a transverse movement of the retaining bracket  220  and need then only be secured against falling out of the groove extension. 
         [0060]    As with the previous embodiments, bearing noses  224  are also provided in this case on the retaining bracket  220  for the bow ends of the vertical chain links wherein in this case however the single retaining bracket  220  is provided on its bracket body  221  with two transverse webs  223  which are spaced from one another corresponding to the spacing between the chain strands, and which have the bearing noses  224  formed on their upper sides. In the illustrated embodiment, the bracket body  221  of the retaining bracket  220  has between each retaining cam  225  and the transverse webs  223  the narrowest cross-section whose width corresponds substantially to the groove width of the groove  211  underneath the groove sections  213  provided with an under-cut section, for this narrow section at least on one side of the bracket body is required so that the bracket end  222 , on the right in  FIG. 10 , may be lowered at the groove extension  212 . 
         [0061]    In the illustrated embodiment the bracket body  220  is again symmetrical. It may however also be provided on one of the intermediate sections between the transverse webs  223  and the retaining cams  225  with a positioning stop, similar to that in the embodiment according to  FIG. 5 , in order to obtain a definite locking position of the retaining bracket  20  and to minimize the movement play of the retaining bracket  220  when the filler member is inserted. 
         [0062]    For the expert numerous modifications are apparent from the preceding description which are to fall within the protective field of the dependent claims. It is evident that the retaining cams and the bracket body can also have different cross-sectional geometrical shapes by means of which the bracket body located in the locking position is secured against vertical movements and against falling out from the insert recess. Furthermore the locking of the retaining bracket may also take place without a filler member and instead of this with spring pins or retaining means which either lie adjoining one of the bracket ends or however engage directly through a bore in the bracket body. The geometrical shape and formation of the scraper wings may vary since in particular this geometrical shape is as a rule adapted to the geometrical shape of the guide profiles of the chain scraper conveyor. 
       INDUSTRIAL APPLICABILITY 
       [0063]    The exemplary disclosed scraper, scraper bridge, and retaining bracket are used in underground mining applications, and in connection with a chain scraper conveyor, particularly with a twin chain scraper conveyor. 
         [0064]    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.