Abstract:
This invention relates to a connection for two ends ( 2,4 ) of a conveyor belt ( 1 ), comprising connection elements ( 6 ) which are attached by means of fixing elements ( 7 ) to the conveyor belt ends ( 2, 3 ). A covering ( 17 ), which covers the connection elements ( 6 ) and the fixing elements ( 7 ) thereof, is disposed on at least one face of the conveyor belt ( 1 ). A fastener ( 21 ) for the covering ( 17 ) cooperates with the connection elements ( 6 ). In order to create a connection which is distinguished by its particularly prolonged durability, the invention essentially proposes that the respective fastener ( 21 ) is attached to one or both limbs ( 11 ) of the connection element of U-shaped form, or to a plate or to plates which are disposed on both faces of the conveyor belt and which rigidly connect the conveyor belt ends. (FIG.  2 ).

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to the connection of two ends of a conveyor belt, comprising connection elements which are attached by means of fixing elements to the conveyor belt ends, wherein a covering is disposed on at least one face of the conveyor belt and covers the connection elements and the fixing elements of the connection elements which are disposed on this face, and wherein holding means which cooperate with the connection elements are provided for the covering. 
     A connection of this type for two ends of a conveyor belt is known from DE 37 09 594 C1. The covering there is attached to the connection elements in the intermediate space between the two ends of the conveyor belt. The result is that the covering covers the ends of the conveyor belt whilst protruding forwards and backwards in the direction of conveying. In particular, this covering is of resilient, preferably of elastic construction, and consists of steel and/or of plastics. When the covering is installed according to one specific embodiment, a coupling element which is constructed as a rod passes through the overlapping ends of connection elements which are connected to different conveyor belt ends and passes through the holding means of the covering. The covering is thus swivel-mounted on the rod. In another specific embodiment the covering is fixed at a distance from the rod. The covering comprises holding elements at a distance from the rod, which are provided with holes through which holding rods pass. These holding rods fit behind the mutually facing limbs of the connection elements. 
     A connection of this type for two ends of a conveyor belt is distinguished only by its inadequate durability. This applies in particular if heavy or irregularly shaped materials or objects, particularly coal, ores, etc. are to be conveyed by means of the conveyor belt. Broken-off parts of the materials to be conveyed and/or small particles which are formed when the materials move in relation to each other penetrate beneath the covering, so that the latter protrudes in relation to the material being conveyed. This thus results in increased wear of the covering and ultimately of the connection and fixing elements. There is a risk of the covering breaking down and of individual connection elements suddenly breaking, so that the material being conveyed can thus no longer be conveyed reliably. In particular, if a stripping device is provided which projects into the path of the material being conveyed and diverts the latter from the conveyor belt, there is a particularly pronounced relative movement between the material being conveyed and the conveyor belt, which relative movement also occurs in the region of the covering and of the connection and fixing elements. This results in the connection between the ends of the conveyor belt being subjected to an even higher degree of wear. A repair for the purpose of installing new connection elements at the belt ends and of installing a new covering consumes a considerable amount of time, with the consequences of a stoppage of the conveyor belt and of reduced economic efficiency. 
     When the conveyor belt moves over a deflection roller an increase in noise emission is observed, since the metal connection and fixing elements are passed over deflection rollers which are generally made of metal. Due to its weight, the material which is conveyed on the conveyor belt thereby presses the connection and fixing elements against the deflection roller with a considerable force. 
     A protective cap for conveyor belt connectors, which consists of rubber or of an equivalent flexible material, is known from DE-PS 826 723. The protective cap penetrates the spaces between the connection elements in the region between the two conveyor belt ends and is joined to a rod-shaped installation element. The protective cap extends in the manner of a bead slightly above the conveyor belt level with respect to the top and bottom faces thereof. 
     The connection of two ends of a conveyor belt in the form of a hinged joint or in the form of a hingeless connection is known from DE 42 35 759 A1 for example. The connection element there is of U-shaped construction, and connection elements which are attached to different conveyor belt ends are either joined in the region of their U-shaped loop by means of a coupling element, or each connection element comprises a rigid plate. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is further to develop a connection of the type cited at the outset so that it is distinguished by its particularly long durability. The object is also to achieve a reduced emission of noise for a connection such as this. 
     This object is achieved for a connection for two ends of a conveyor belt of the type cited at the outset in that the respective connection element is of U-shaped construction, and connection elements which are attached to different conveyor belt ends are connected in the region of their U-shaped loop by means of a coupling element, or in that the respective connection element comprises a rigid plate, wherein the respective holding means is attached to one or both limbs of the U-shaped connection element or to the plate or to plates disposed on both faces of the conveyor belt. 
     Provision is thus made according to the invention for the holding means for the covering to be directly attached to the connection elements. Thus, when the material being conveyed acts on the covering above the latter, there are no forces which are transmitted into coupling elements or the like which pass through the connection elements which mesh with each other. Instead, the holding means constitute a rigid connection between the covering and the connection elements. According to one particular embodiment, the respective holding means is screwed to the connection element or is inserted through the latter, and in particular is screwed into or passed through a hole in the limb or in the plate, which hole is suitable for receiving the fixing element. In principle, very different components can be used as holding means for the covering, for example nails, pins or staples. However, screws are considered to be particularly advantageous fixing means, especially those screws which are of self-tapping construction. In order to be able to position the covering layer in as simple a manner as possible with respect to the conveyor belt ends and the connection elements, the covering should have a plurality of alignment holes which are aligned with holes in the connection elements. Alignment is effected by inserting a pin in the respective alignment hole and in the hole in the connection element which is associated therewith. 
     The covering itself can be of different forms. Since it is subject to wear, it should advisedly be replaceable. This can be achieved particularly simply and rapidly by fixing the covering by means of screws. It is also possible to incorporate the covering in a cast part which in particular is installed together with the connection and fixing elements. 
     In the sense of the present invention, it is sufficient if the covering is disposed on that face of the belt which faces the material being conveyed. One particular embodiment of the invention provides for the covering also to be provided on the face facing away from the material being conveyed. It is thus impossible for the metal connection and fixing elements to contact the deflection rollers in the region of the deflection rollers. Instead of this, the covering is passed around the deflection roller with reduced noise. This is also associated with a reduction in wear of the elements. 
     A design which is fundamentally different provides for the holding means to be constructed as a projection which is inserted in a complementary recess in the covering. A particularly simple form of the projection results if the latter is of plate-like construction. The holding means preferably forms a constructional unit with the connection element. It is thus unnecessary for the holding means to be installed in a separate operation. In particular, the holding means is constructed as a projection, preferably as a plate-like projection, which is attached to the limbs of the connection element or which is attached to the plate if a hingeless connection is formed. When the holding means is constructed as a projection, it is possible in particular for the covering to be slid on to the projection. In particular, sliding is effected perpendicular to the direction of travel of the conveyor belt in the conveying plane thereof. If the conveyor belt is outwardly curved, it is also possible to fit the covering substantially radially on to the holding means. 
     One possible design provides for the ends of the conveyor belt to be of a reduced thickness and for the covering to be disposed in the recess of the conveyor belt which is thus formed. In the ideal situation, the surface with which the material being conveyed comes into contact forms a plane with the surface of the conveyor belt. 
     For example, if the conveyor belt is designed as a single-layer textile conveyor belt which is provided with a top and bottom covering sheet made of rubber, the top covering sheet can be removed in order to receive the covering. The covering can be pushed into or inserted in a dovetail-like transverse recess in the conveyor belt. If the ends of the conveyor belt are not of reduced thickness, the covering which is placed on the conveyor belt ends should be of reduced thickness at the front and back with respect to the direction of travel of the conveyor belt. 
     The covering preferably consists of an elastomer, particularly rubber or polyurethane, or of polyvinyl chloride or of a composite of an elastomer and metal. The composite part may have a central rubber section, for example, which is adjoined by metal sections at the front and back in the direction of conveying. According to one fundamentally different design, the covering forms a cast unit with the connection elements. As a consequence of this, the connection elements are installed together with the covering. The casting material is preferably an elastomer. The cast unit may comprise a textile reinforcement, for example. 
     The covering may either extend over the entire width of the conveyor belt or may be formed from individual segments which are disposed side-by-side. In particular, the covering is constructed as individual segments if the conveyor belt is moved over rollers comprising a recessed zone. 
     Other features of the invention are illustrated in the subsidiary claims, in the description of the figures and in the figures themselves, wherein it should be remarked that all the individual features and all combinations of individual features are an essential part of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated by way of example in the figures with reference to various embodiments, without being restricted thereto. The figures are as follows: 
     FIG. 1 is a plan view of half of a conveyor belt which is fashioned with a hinged connection and with the covering according to the invention, in the region of the two conveyor belt ends; 
     FIG. 2 is a section through the connection between the two ends of the conveyor belt and through the covering, along line II—II in FIG. 1; 
     FIGS. 3 to  7  show different forms of the connection and of the covering, in a sectional view corresponding to that of FIG. 2; 
     FIG. 8 is a plan view of a hingeless connection between two ends of a conveyor belt and the covering thereof for the region shown in FIG. 1; 
     FIG. 9 is a section through the connection and the covering along line IX—IX in FIG. 8; and 
     FIGS. 10 to  18  show different forms of the hingeless connection and of the covering, as sectional views corresponding to the illustration in FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show the hinged connection of two ends of a conveyor belt  1 . The latter is driven in the direction of arrow A. The front conveyor belt section  2  with respect to the direction of travel A is delimited at the back by the edge  3 , and the rear conveyor belt section  4  is delimited by the front edge  5 . There is a multiplicity of connection elements which are attached by means of staples  7  to the conveyor belt sections  2  and  4  in the region of the front and rear edges  5 ,  3  thereof, as is disclosed in the prior art according to DE 42 35 957 A1 for example. 
     Each connection element  6  comprises an arcuate loop crosspiece  10  and two limbs  11  for the formation of a loop  8  for a coupling rod  9 , wherein each limb  11  is provided with four holes  16  for receiving the limbs  13  of two staples  7 . The conveyor belt  1  is constructed as a single-layer textile conveyor belt and comprises top and bottom covering sheets made of rubber, which are not illustrated. In the embodiment shown in FIGS. 1 and 2, the top covering sheet has been removed, by shaving it off for example, in the region of the respective belt end. The U-shaped connection elements  6  have been pushed on to the belt ends in this diminished region and are attached by means of the staples  7  to the conveyor belt sections  2  and  4 . Projections  15 , which are provided on the connection elements and which make contact with the end face of the respective conveyor belt section  2  or  4 , serve as limit stops when the connection elements  6  are installed. The individual connection elements  6  of a conveyor belt section are fixed to each other by means of a rod which is not shown but which is disposed in the region of the projection  15  and is oriented perpendicularly to the direction of travel of the belt, so that these connection elements can be fitted as a unit to the respective conveyor belt section  2  or  4 . The respective staple  7  is introduced from the face of the conveyor belt  1  into the associated connection element  6  which is remote from the covering sheet which has been removed. After driving in the staples  7 , the free end regions of the staple limbs  13  are bent off at right angles behind the associated limb  11  of the connection element  6  and thus clamp the respective conveyor belt section between the limbs  11  of the connection element  6 . On account of the course of the section shown in FIG. 2, only the staple  7  of the leading connection element  6  in the direction of travel is visible, and the staple of the trailing connection element is not visible. As can be seen from the regions on the left of FIG.  2  and of FIG. 1, not all the holes  16  in the connection elements  6  are used for receiving staples  7 , but the four holes which are usually employed for receiving a staple  7  remain free in each second connection element  6 . 
     FIGS. 1 and 2 show that a sheet-like rectangular covering  17  is inserted in the region of the removed top covering sheet, the thickness of which covering when it rests on the connection elements  6  is designed so that its upper face  18  is in alignment with the upper faces  19  of the conveyor belt sections  3  and  4 . The dimension of the covering  17  in the direction of conveying of the belt is selected so that it can be inserted with a slight clearance in the recess  24  of the conveyor belt  1 . The covering  17  can extend over the entire width of the conveyor belt or can be formed from individual segments which extend over only part of the width of the conveyor belt and which are disposed at a defined spacing from each other, so that the belt can be moved in particular through a recessed zone of a conveyor roller. Twelve screws  21 , which serve to attach the covering  17  to the connection elements  6 , are provided for the connector strip shown in FIG. 1, which consists of twelve mutually meshing connection elements  6 . The screws  21  are self-tapping, so that they can be screwed directly into the respective, mutually aligned holes  16  in the limbs  11  of the connection elements  6 . A countersunk region  23  in the covering  17  is provided for the screw head  22 . On account of the course of the section selected in FIG. 1, FIG. 2 only shows the connection of the covering  17  to the rear conveyor belt section  4 . The covering may consist of rubber for example. 
     In the embodiment shown in FIG. 1, a rigid connection is produced on account of the circumstance that the respective screw  21  passes through both limbs  11  of the associated connection element  6 . This assumes that the covering layer is quite flexible so that it can deform when the conveyor belt  1  is in operation. The embodiment shown in FIG. 2 differs from that shown in FIG. 1 in that the respective screw  21  is only screwed into the limb  11  of the respective connection element  6  facing the covering  17 , and a sufficiently large gap  25  is formed in the recess  24  of the conveyor belt  1 , in front of and behind the covering  17  with respect to the direction of travel of the belt, so that in this case the covering  17  can be of stiffer construction. 
     The embodiment shown in FIG. 4 exhibits basic similarities to that shown in FIG.  2 . The covering layer of the conveyor belt  1  is not removed, however, so that the belt has no recess  24 . The covering  17  made of rubber is placed directly on the upper face  19  of the conveyor belt sections  2  and  4  and in the central section of its face which faces the conveyor belt  1  it has a recess  26  which serves to receive the upper limbs  11  of the connection elements  6 . The covering  17  is provided with a bevel  27  at the front and at the back with respect to the direction of travel, so that any material being conveyed which moves in relation to the conveyor belt  1  cannot become caught on a sudden edge of the covering  17 . 
     The embodiment shown in FIG. 5 differs from that shown in FIG. 4 in that nut and bolt connections  31  are provided here for fixing the covering  17  instead of screws  21 . A bolt  12  is inserted from above into the respective countersunk region  23 , through the hole in the covering  17  and through the holes  16  in the limbs  11  of the associated connection element  6 , and passes through a hole in a bottom covering  28 , the countersunk region  29  of which receives the nut  30 . Thus in this embodiment a bottom covering  28  is also used. This bottom covering is fashioned corresponding to the covering  17  in the embodiment shown in FIG. 4, and due to its bevels  27  ensures that the conveyor belt  1  can pass over a deflection roller which contacts the lower face of the conveyor belt  1  with a reduced noise level. Apart from this, the deflection rollers or running rollers of the conveying system are protected due to the bottom covering  28 , since they do not come into contact with the metal connection elements and with the means which are used for the fixing thereof. In addition, the two coverings  17  and  28  are provided with holes  32 , which serve to simplify the positioning of the coverings. For this purpose, a mounting pin, which is not shown, is inserted through the mutually aligned holes  32  and  16 . 
     The embodiment shown in FIG. 6 differs from that shown in FIG. 5 in that the top covering  17  is not disposed in a recess, but instead of this is of corresponding construction to the bottom covering  28 . 
     The embodiment shown in FIG. 7 is similar to that shown in FIG.  1 . Here, an additional metal plate  33  is employed for fixing the covering  17 , which is inserted from the face into the recess  24 , which in this case is a dovetail-like recess. The metal plate  33 , which projects beyond the connection elements  6  at the front and the back with respect to the direction of travel, is placed on the connection elements  6  which are fixed to the conveyor belt sections  2  and  4 . The metal plate  33  contains holes, wherein two screws  21 , which pass through the two limbs  11  of the associated connection element  6 , are employed at each connection point for fixing the metal plate  33  to the connection element  6 . The covering  17  is constructed as a composite part. It consists of a central sheet-like section  34  made of rubber, the front and rear end faces of which are attached to wedge-shaped sections  35  made of metal, which are formed corresponding to the shape of the dovetail, wherein tongues  36  which are attached to the sections  35  protrude into grooves in the sheet-like section  34 . The upper face  18  of the covering  17  protrudes slightly above the upper faces  19  of the two conveyor belt sections  2  and  4 . 
     The embodiment shown in FIGS. 8 and 9 comprises a hingeless connection of the two conveyor belt sections  2  and  4 . Connection elements  6  are used here which comprise rigid plates  37  which are oriented in the direction of conveying of the belt  1 . In order to receive four staples  7  in each case, each plate  37  which is attached to the upper face of the conveyor belt  1  is provided with four holes  16  and each lower plate  37  is correspondingly provided with four holes  16 . Parts which perform a function corresponding to the parts of the embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals in FIGS. 8 and 9 and in subsequent figures. 
     Apart from the difference of the hingeless connection, the embodiment shown in FIG. 9 corresponds to that shown in FIG.  2 . However, the staples  7  have not been driven in from below but have been driven in from above, and the top covering  17  is provided in addition with the positioning holes  32 . The embodiment shown in FIG. 10 comprises a hingeless connection, but otherwise constitutes a variant which corresponds to the embodiment shown in FIG.  3 . With respect to the hingeless connection, FIG. 11 constitutes a variant which is comparable with that of FIG. 4, FIG. 12 constitutes a variant comparable with that of FIG. 5, FIG. 13 constitutes a variant comparable with that of FIG. 6, and FIG. 14 constitutes a variant comparable with that of FIG. 7, wherein in the embodiment shown in FIG. 14 only one screw  21  is used each time instead of two screws  21 . The embodiment shown in FIG. 15 differs from that shown in FIG. 14 in that the covering  17  does not constitute a composite component but consists of one material, for example rubber, polyurethane or another similar elastomer, or may optionally consist of polyvinyl chloride also. 
     The embodiment shown in FIG. 16 differs from that shown in FIG. 15 in that a metal plate  33  which is attached to the upper rigid plate  33  is not provided, but that the rigid plate  37  is modified by providing it with projections  38  which are directed obliquely upwards in the region of its front and rear ends with respect to the direction of travel of the conveyor belt  1 , which projections function as holding means in this case. It is therefore unnecessary to provide holding means in the form of the screws  21  or in the form of the nut and bolt connection  31 , optionally in combination with the separate metal plate  33 . The rigid plate  37  comprising the projections  38  is provided with holes corresponding to those in the lower plate  37  and the two plates  37  are joined by means of four staples  7 , and they clamp the conveyor belt sections  3  and  4  between them in the region of reduced thickness of the conveyor belt  1 . The covering  17  is preferably inserted transversely to the direction of travel of the conveyor belt  1  into the dovetail-like recess  24  which is formed. 
     The embodiment shown in FIG. 17 differs from that shown in FIG. 16 in that a reinforcement  39  is inserted in the covering  17 . This reinforcement is constructed in particularly as a metal or textile reinforcement. Specifically, a thin-walled reinforcing element made of metal is provided here, the middle region of which extends parallel to the plate  37  and the end regions of which are bent around the projections  38 . The effect of these end regions inside the covering  17 , which consists of rubber, is that the wedge-shaped ends of the covering are held under spring pressure in the dovetail-like corner regions of the recess  24 . 
     The embodiment shown in FIG. 18 basically differs from the embodiments described above in that the covering  17 , together with the holding means, forms a cast unit  40 . The casting material is preferably an elastomer. The cast unit comprises the plate  37 , which is provided on its underside with ribs of low height which are not illustrated in the figure. A textile section  41 , which extends above the plate  37  at the front and back with respect to the direction of travel of the conveyor belt  1 , is placed on the plate  37 . The parts are cast with each other, wherein the casting material completely surrounds them and thus penetrates under the plate  37  also, on account of the ribs. Casting technology measures are employed which ensure that the holes in the plate  37  and in the textile section  41  which serve to receive the staples remain free. The casting material is cast to a height such that it has the contour of a right parallelepiped and can be inserted in the parallelepiped-shaped recess  24  in the conveyor belt  1 . This is followed by the attachment of the cast unit  40  by means of the staples  7 , wherein the ends of the latter are bent around behind the plate  37  which is mounted on the lower face of the conveyor belt sections  2  and  4 .