Abstract:
The invention relates to a belt conveyor which comprises a conveyor belt ( 20 ) that is guided around at least one return shaft ( 30 ), thereby forming an upper run and a lower run, and a drive device for moving the conveyor belt ( 20 ), characterized in that the drive device is preferably arranged in a separate manner from the return shaft ( 30 ) and drives the conveyor belt ( 20 ) in the area of a deflection between upper run and lower run. The drive device preferably comprises a toothed belt ( 40 ) or V-belt arranged at an edge section of the conveyor belt ( 20 ) and a rotationally drivable toothed wheel ( 60 ) or a V-belt disk. The toothed belt ( 40 ) or V-belt is connected or connectable, preferably in a releasable manner, to the conveyor belt ( 20 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a belt conveyor, a method for mounting the belt conveyor, and the use of a drive device for a belt conveyor. 
         [0003]    2. Description of the Related Art 
         [0004]    In a belt conveyor or rope belt conveyor, an elastic and/or bendable conveyor belt is usually driven in a continuous manner by the conveyor belt being guided around return shafts or return pulleys. Here, at least one return pulley is driven by a motor, so that a load-bearing upper run of the conveyor belt travels in one direction, whereas a lower run travels in the opposite direction on a lower side. The conveyor belt is subject to wear and needs to be replaced after a certain period of time or a certain number of working hours. The replacement of the conveyor belt is difficult and time-consuming, since particularly in the case of an endless belt a multitude of parts of the belt conveyor needs to be demounted and subsequently be mounted again. 
         [0005]    Thus, it is the object of the invention to provide a belt conveyor in which a conveyor belt can be replaced in a simple and cost-saving manner within a short period of time. 
       SUMMARY OF THE INVENTION 
       [0006]    according to one aspect of the invention, the belt conveyor comprises a conveyor belt that is guided around at least one return shaft to form an upper run and a lower run, and a drive device for moving the conveyor belt, wherein the drive device is arranged and/or mounted or fixed separately from the return shaft and drives the conveyor belt ( 20 ) in the area of a deflection between the upper run and the lower run. In other words, the drive device is mounted to a frame or mounting frame in a preferably fully separate manner from the return shaft. A vertical upper portion of the conveyor belt is referred to as an upper run, on which the items or goods are transported and which moves in the conveying direction, whereas a portion of the conveyor belt travelling back below and opposite to the conveying direction is referred to as a lower run. Preferably, the drive device is arranged in the area of the at least one return shaft. 
         [0007]    Demounting/Mounting of the drive device upon replacement of the conveyor belt is not necessary due to the drive device being arranged separately from the return shaft. It is absolutely sufficient to demount the return shaft to install a new conveyor belt. The drive device, however, may remain mounted in the frame of the belt conveyor during the replacement operation of the conveyor belt. Thus, the conveyor belt can be replaced in a simple manner and accordingly, only low mounting costs occur for the replacement of the conveyor belt. For example, the drive device comprises a gear or a V-belt pulley for engagement with a toothed belt or V-belt arranged on the conveyor belt, and preferably a motor for mechanically driving the gear or the V-belt pulley to drive the conveyor belt via the engagement with the toothed belt or V-belt. 
         [0008]    An electric motor, such as an AC motor or a three-phase AC motor, is preferably used as the motor. However, any other motor, such as a DC motor, a hydraulic motor, a pneumatic motor, an internal combustion engine or the like, can be used as well depending on the application purpose. 
         [0009]    Preferably, the drive device comprises a toothed belt or V-belt, which is arranged on an edge portion of the conveyor belt, and a rotatably drivable gear or a V-belt pulley, which is preferably coupled to an electric motor. Further preferably, an axis of the gear or the V-belt pulley is preferably located on an elongation of an axis of the return shaft. 
         [0010]    Further preferably, the at least one return shaft can be demounted separately from the gear or the V-belt pulley. Preferably, two return shafts are arranged, one at an end of the belt conveyor each. 
         [0011]    According to a preferred embodiment, the return shaft comprises a plurality of roll bodies, which are arranged next to each other and which can be rotated preferably independently from each other. 
         [0012]    A speed difference of the conveyor belt in the width direction, in particular in the case of a curved belt, can be preferably compensated for by the return shaft comprising a plurality of roll bodies, which are arranged next to each other and which can be rotated preferably independently from each other. In other words, in the case of a curved belt, a radially outer portion has a higher cycle speed than a radially inner portion, and accordingly these portions need to be moved or guided around the return shaft at different speeds. These speed differences can be realized gently by the roll bodies, which are arranged next to each other, being rotatable independently from each other. 
         [0013]    Alternatively, the return shaft may be formed integrally and conically to compensate for speed differences of the conveyor belt. 
         [0014]    Preferably, the return shaft can be arranged and/or mounted by being hung in the frame of the belt conveyor. The return shaft can preferably be shifted and/or fixed in a longitudinal direction of the belt conveyor to tension the conveyor belt. 
         [0015]    Demounting/Mounting of the return shaft upon replacement of the conveyor belt can be performed in a simple and fast manner due to the return shaft merely being hung in the frame of the belt conveyor. In addition, the conveyor belt can be tensioned by shifting the return shaft in a longitudinal direction of the conveyor belt. Thus, a separate tensioning device for tensioning the conveyor belt is not required. Therefore, the belt conveyor can be produced with a minimum of individual parts. 
         [0016]    Preferably, the hung in return shaft can be tensioned by means of a biased pneumatic spring. The pneumatic spring is preferably configured such that it automatically locks in place or is adjusted when the conveyor belt is in a fully relaxed position, i.e. when the return shaft is displaced inwardly or opposite to the tensioning direction. Due to the adjustment of the pneumatic spring, the return shaft can be easily taken off from its bearing to exchange the conveyor belt. The adjustment can preferably be released manually in order to initiate the tensioning of the conveyor belt after mounting simply by releasing the adjustment of the pneumatic spring. 
         [0017]    Preferably, the at least one return shaft is arrangeable or arranged on at least one end of a belt curve. In other words, the belt conveyor is formed as a curved belt conveyor, and the return shaft redirects the conveyor belt downward to establish a connection between the advancing upper run and the returning lower run of the conveyor belt. 
         [0018]    According to a further aspect of the invention, the belt conveyor comprises a conveyor belt, which is guided around at least one return shaft, and a drive device for moving the conveyor belt, preferably according to one or more of the preceding aspects, wherein the conveyor belt comprises a toothed belt or V-belt engaged with the drive device and releasably connected or connectable to the conveyor belt. 
         [0019]    A toothed belt, or V-belt, or a conveyor belt can be replaced separately due to the toothed belt or V-belt for driving the conveyor belt being releasably connected or connectable to the conveyor belt. Thus, costs for replacing worn components can re reduced, since depending on the state of wear the toothed belt or V-belt can be replaced without the conveyor belt or the conveyor belt can be replaced without the toothed belt or V-belt. 
         [0020]    Preferably, the toothed belt or V-belt has a lateral extension connected or connectable to the conveyor belt. 
         [0021]    Further preferably, the lateral extension has a plurality of tabs, which are separated from each other by recesses and which are connectable or connected to the conveyor belt preferably by rivets. 
         [0022]    The tabs that are separated from each other by recesses offer the advantage of a preferred power transmission from the toothed belt or V-belt to the conveyor belt with, at the same time, a lateral or angular shiftability of the toothed belt or V-belt with respect to the conveyor belt, which is possible in predetermined limits. Thereby, construction errors or tolerances can be compensated for, so that a smooth operation of the belt conveyor is made possible even in the case of relative high tolerances. In addition, the production costs can be minimized due to relatively high tolerances in the production and maintenance of the belt conveyor. The output of the manufactured components can be increased though, since only a low scrap quantity is produced with these high tolerances. 
         [0023]    Furthermore, the conveyor belt can position itself in the recesses or troughs at the return points between the tabs of the lateral extension in order to minimize longitudinal tensions in the deflection. 
         [0024]    Finally, no high adjustment and orientation tolerances are to be stuck to when mounting the belt conveyor, whereby the mounting time and mounting costs can be minimized. 
         [0025]    The toothed belt or V-belt can be released from the conveyor belt and connected to another conveyor belt in a simple manner due to the conveyor belt being connected to the toothed belt or V-belt by means of rivets. Alternatively or in addition, other fastening elements, such as screws, splints, press studs, etc., can be used as well. 
         [0026]    Preferably, the toothed belt or V-belt comprises at least a first tension-bearing member layer preferably arranged in the interior thereof, which is arranged lengthwise to a movement direction of the toothed belt or V-belt. 
         [0027]    The toothed belt or V-belt can transfer high driving forces due to the toothed belt or V-belt comprising a first tension-bearing member layer, preferably a pair of first tension-bearing member layers, which is arranged in a longitudinal direction or movement direction of the toothed belt or V-belt. In addition, a lengthening of the toothed belt or V-belt is largely avoided even in the case of high mileage. Thus, even after many working hours there are no disturbances caused by a changed spacing or a changed distance of teeth of the toothed belt or V-belt and/or the sagging of a lower run of the toothed belt or V-belt. 
         [0028]    In particular in the case of a curved belt conveyor, blocking of a drive device due to lengthening, as might occur with the use of a chain instead of the toothed belt or V-belt, can be avoided. 
         [0029]    Further preferably, the toothed belt or V-belt comprises at least a second tension-bearing member layer preferably arranged at an angle of 30° to 50° with respect to the movement direction of the toothed belt or V-belt. 
         [0030]    Due to the toothed belt or V-belt comprising the second tension-bearing member layer, which is arranged at an angle of 30° to 50° with respect to the movement direction of the toothed belt or V-belt, large forces can be transferred to the conveyor belt b the toothed belt or V-belt without deforming the tabs excessively. In addition, the bending behavior of the toothed belt or V-belt during the deflection at the gear or the V-belt pulley can be optimized due to the angular arrangement of the second tension-bearing member layer. In other words, the relatively rigid second tension-bearing member layer does not or only slightly influence the bending behavior of the toothed belt or V-belt, since the second tension-bearing member layer is arranged at an angle to the movement direction of the toothed belt or V-belt. Furthermore, the angular position of the second tension-bearing member layer preferably corresponds to a line of force, which transfers the driving force from the toothed belt or V-belt to the conveyor belt. Here, the second tension-bearing member layer is arranged across the entire length of the toothed belt or V-belt angularly to an extension of the toothed belt or V-belt. 
         [0031]    Preferably, the second tension-bearing member layer extends into the lateral extension and/or tabs. 
         [0032]    Further preferably, at least one tensile-load bearing member of the first and/or second tension-bearing member layers has at least one layer of woven warp and weft threads. It is best for the first tension-bearing member layer to have a regular lay or Lang&#39;s lay rope, and the second tension-bearing member layer preferably has at least one layer of woven warp and weft threads. 
         [0033]    The toothed belt or V-belt preferably contains polyurethane and is preferably welded and/or glued to the tabs and/or the extension, which also contain polyurethane. However, the toothed belt or V-belt may also be formed integrally with the lateral extension or the tabs in order to do without the step of welding/gluing in the production. 
         [0034]    Preferably, the conveyor belt is an endless belt. Thus, it is possible to do without a mounting step of connecting belt ends, and loosening of a belt connection during operation can be avoided. 
         [0035]    According to a further embodiment, such a belt conveyor may comprise a clamping surface provided on the conveyor belt or on the lateral extension, which is in contact with a frame-side clamping member that applies a clamping force directed transversely to the longitudinal direction of the conveyor belt to the clamping surface. The clamping force may be slighted toward the conveyor belt plane, so that the clamping element is pushed toward one or more abutments that may be arranged on the side of the conveyor belt opposite to the clamping member, and may e.g. be formed by idler roller. In a curved belt, a component of the clamping force may be directed radially outwardly, so that the clamping force lies within a radius plane in which the radius of the curve falls and which is perpendicular to the conveyor belt. 
         [0036]    With such a belt conveyor, the clamping surface may be provided on the toothed belt or on a V-belt and/or on a clamping element formed in addition to the toothed belt. A clamping element formed in addition to the toothed belt or V-belt may be formed integrally with the toothed belt or V-belt or as a separate element having a multi-part design, which can be formed or fixed separately on the conveyor belt or the extension. 
         [0037]    Moreover, with such a belt conveyor, the toothed belt or V-belt and/or the clamping element may be arranged on the inner side of the continuous conveyor belt. On the inner side of the continuous conveyor belt means on the side of the return shaft. As described, the parts may be arranged directly or indirectly on the conveyor belt, i.e. on the conveyor belt itself or on the lateral extension of the conveyor belt. Preferably, the arrangement, in particular of the clamping element, is only on the inner side of the continuous conveyor belt, thus on the pressure side of the belt with respect to the neutral fiber. Accordingly, no clamping element would be arranged on the outer side of the conveyor belt. The clamping element would thus not be tensioned when the conveyor belt passes the return shaft. 
         [0038]    Since the conveyor belt is designed as an endless belt, it can be mounted by simply being placed on the return shaft. Joining of two ends of the conveyor belt can be omitted. Furthermore, such an endless belt runs smoothly, and a connecting point cannot get loosened. 
         [0039]    According to a further aspect, a method for mounting a belt conveyer with the following steps is provided: mounting a drive device on a frame or a basis of a belt conveyor; introducing at least one return shaft into the belt loop, i.e. into the interior of an endless belt or in the interior of a conveyor belt, the ends of which being connected to each other; and hanging the at least one return shaft in the frame or the base of the belt conveyor to cause the mounting of the conveyor belt. 
         [0040]    Since in this mounting method the mounting of the drive device is performed separately from the mounting of the conveyor belt, demounting of the drive device upon replacement of the conveyor belt is not necessary. Thus, the replacement of the conveyor belt can be performed in a fast and cost-efficient manner. 
         [0041]    In addition, also the drive device can be mounted and demounted separately from the mounting of the conveyor belt, so that the conveyor belt and the return shaft can remain mounted when the drive device is being replaced. This also has the advantage of cost and time saving. 
         [0042]    Furthermore, according to an aspect of the invention, a drive device having a rotatably drivable gear or a V-belt pulley for driving a belt conveyor designed as described above is used. 
         [0043]    In the following, the invention will be described in more detail with reference to the accompanying drawings by way of an embodiment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0044]      FIG. 1  shows a perspective view of the belt conveyor according to the invention in the form of a curved belt conveyor, with a conveyor belt being demounted. 
           [0045]      FIG. 2  shows a detailed view of the belt conveyor according to the invention of  FIG. 1 , with a conveyor belt being mounted. 
           [0046]      FIG. 3  shows a sectional view of the belt conveyor with a further embodiment of a placed conveyor belt with a toothed belt and a clamping element. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0047]    The curved belt conveyor shown in  FIG. 1  comprises a frame  10  that is formed by a pair of longitudinal beams or double-T beams  12 . A return shaft  30  for returning a conveyor belt (not shown) is each arranged at the ends of the double-T beam  12 . 
         [0048]    The return shaft  30  is hung in the frame  10 , wherein at least one of the two return shafts  30  is shiftable in a longitudinal direction or a movement direction of the not-shown conveyor belt in order to be able to clamp the conveyor belt after mounting thereof. 
         [0049]    In addition, the return shaft  30  comprises a plurality of roll bodies  32  that can be rotated independently from each other. Since the conveyor belt has a lower cycle speed on an inner side, i.e. on a side with a smaller bending radius, than on an outer side or a side with a large bending radius, a roll body  32  arranged on the inner side needs to have a correspondingly lower cycle speed than a roll body  32  arranged on the outer side. 
         [0050]    In addition, there is mounted to the frame  10  an electric motor  70  with a gear  60  for driving a toothed belt not shown in  FIG. 1 . Preferably, the gear  60  is arranged directly on an output shaft of the electric motor  70 . The unit consisting of the electric motor  70  with the gear  60  can be mounted or demounted to the frame  10  independently from the return shaft  30 . On the other hand, the return shaft  30  can be mounted or demounted independently from the drive unit consisting of the electric motor  70  and the gear  60 . 
         [0051]    The drive device with the gear  60  is preferably positioned or positionable such that an axis or rotational axis of the gear  60  lies substantially on an axis or rotational axis of the return shaft  30 . 
         [0052]    In addition, the belt conveyor comprises a plurality of idler rollers  80  for guiding the toothed belt (not shown). Preferably, the height of these idler rollers  80  is adapted to the thickness of the toothed belt. Alternatively, the idler rollers  80  may also be arranged in a vertically shiftable manner to facilitate mounting of the toothed belt and to be able to adjust their height according to the thickness of the toothed belt. Moreover, on the frame side there is arranged a plurality of clamping members formed as clamping rollers  81 , which according to the illustrated embodiment are arranged on the other side of the conveyor belt, not shown in this figure, with respect to the idler rollers  80 . 
         [0053]      FIG. 2  shows a detailed view of the belt conveyor of  FIG. 1 , a conveyor belt  20  and a toothed belt  40  being mounted in  FIG. 2  though. 
         [0054]    The toothed belt  40  is placed onto the gear  60  with the toothing  46  thereof in order to be engaged therewith. Thus, the toothed belt  40  is driven by driving the gear  60  due to the engagement of the teeth of the gear  60  with the toothing  46 . Thereby, the toothed belt  40  moves along the double-T beam  12  of the frame  10 . This movement of the toothed belt  40  is transferred to the conveyor belt  20  via the tabs  48  (extension) and rivets  50 , so that the conveyor belt  20  is also moved along the pair of double-T beams  12 . 
         [0055]    The toothed belt  40  is provided with at least one first tension-bearing member  42 , preferably with a pair of tension-bearing members  42 , in order to be able to transfer high driving forces without extensively lengthening or extensively loading the toothed belt. When two or more tension-bearing members  42  are arranged, they are preferably arranged next to each other to bend around the gear  60  in a smooth manner. These first tension-bearing members  42  are preferably formed as a regular lay or Lang&#39;s lay rope, while the toothed belt  40  is preferably made of polyurethane. 
         [0056]    Preferably, in the extension or tab  48  there is arranged a plurality of second tension-bearing members, which can form a second tension-bearing member layer  43  to transfer the driving force from the toothed belt  40  to the conveyor belt  20 . These second tension-bearing members of the second tension-bearing member layer  43  preferably comprise at least one layer of woven warp and weft threads and are preferably arranged at an angle with respect to the movement direction of the toothed belt, preferably at an angle of 30 to 50 degrees, most preferably at an angle of 40 to 45 degrees. 
         [0057]    Preferably, the direction of the angularly arranged second tension-bearing members  43  substantially corresponds to a line of force for inducing the movement force from the toothed belt  40  to the conveyor belt  20 . Moreover, further second tension-bearing members can preferably be arranged perpendicularly to the second tension-bearing members in the force-inducing direction. In other words, there are second tension-bearing members  43  that are arranged at an angle of 30 to 50 degrees, i.e. at an angle substantially in correspondence with a force-inducing direction, and further second tension-bearing members  43  that are displaced by 90 degrees with respect to the first-mentioned second tension-bearing members. This has the advantage that when the movement direction of the belt conveyor is reversed, the further last-mentioned second tension-bearing members  43  now substantially correspond to the force-inducing direction from the toothed belt  40  to the conveyor belt  20 . 
         [0058]    In summary, one can say that second tension-bearing member layers  43  are arranged such that a plurality of second tension-bearing members  43  is each arranged in the force-inducing direction both in the one movement direction of the belt conveyor and in the opposite movement direction of the belt conveyor. 
         [0059]    The tabs or extensions  48  of the toothed belt  40  are connected to the conveyor belt  20  preferably by rivets  50 . In this way, a simple and cost-efficient connection between the toothed belt  40  and the conveyor belt  20  is provided. If the conveyor belt  20  or the toothed belt  40  is replaced, this connection can be released and reestablished in a simple manner. Alternatively, this connection may also be established by another connection method, such as screwing, splints, gluing, vulcanizing, etc. 
         [0060]    The invention particularly relates to a belt conveyor having a conveyor belt  20 , which is guided around at least one return shaft  30 , and a drive device for moving the conveyor belt  20 , wherein the drive device is preferably arranged separately from the return shaft  30 . The drive device preferably comprises a toothed belt  40 , which is arranged or arrangeable on an edge portion of the conveyor belt  20 , and a rotatably drivable gear  60 . The toothed belt  40  is preferably connected or connectable to the conveyor belt  20  in a releasable manner. 
         [0061]    Objects can be conveyed at an arbitrary angle with the curved belt conveyor shown in the figures. Preferably, clamping means (not shown), such as a curved guide, can act on the radially inward flank of the toothed belt to guide the toothed belt around the curve. 
         [0062]    However, the invention is not limited to the curved belt conveyor as shown, but can also be applied to a straight belt conveyor. In addition, the drive device with the gear  60  and the toothed belt  40  can also be arranged on the inner side or on both sides of the conveyor belt  20  in the case of a curved belt conveyor. Furthermore, instead of the electric motor  70 , an other drive device, such as a hydraulic motor, a servo motor, an internal combustion engine, etc., can be used for driving the belt conveyor as well. The frame  10  does not need to exhibit the double-T beam  12 , but any other kind of frame, such as a simple T-beam, an L-beam, a rod, or a tube, can be used for forming the frame as well. Optionally, the belt conveyor can be provided with guide plates  90 , which are to be connected to the frame  30  in an easy to release manner as well. Although a toothed belt placed around a gear is used as a drive according to the embodiment, a V-belt with a corresponding V-belt pulley can be used as well. 
         [0063]      FIG. 3  shows a sectional view of the belt conveyor with a further embodiment of a placed conveyor belt  20  with a toothed belt  40  and a clamping element  47 . In this embodiment, the clamping element  47  and the toothed belt  40  are arranged on the inner side of the continuous conveyor belt  20 , i.e. on the side of the return shaft not shown in  FIG. 3 . 
         [0064]    In this embodiment, the clamping element  47  is formed with the toothing  46  in addition to the toothed belt and separated therefrom by a gap, which extends between the toothing  46  and the clamping element  47  in the direction of the extension fixed to the conveyor belt  20 . In this embodiment, the gap does not divide the toothed belt and the clamping element  47  completely, so that the two elements are formed integrally in the present case, so that only one integral component needs to be fixed on the extension of the conveyor belt  20 . Furthermore, a first tension-bearing member  42  is shown in this embodiment as well. 
         [0065]    It is also conceivable that the toothed belt or a V-belt provided instead of the toothed belt is provided in a fully separated manner from the clamping element  47 , i.e. with a multi-part design. In this case, the toothing may be arranged on the outer side of the conveyor belt. Due to the toothing, tensile stress in the toothed belt  40  could also be kept low for an arrangement on the outer side. However, it is advantageous that at least the clamping element  47 , which should have a certain uniform constructional height to be able to provide a sufficiently large clamping surface  45 , is arranged on the inner side of the conveyor belt  20 . In the case of an arrangement on the inner side, the clamping element  47  lies within the continuous neutral fibre of the conveyor belt, i.e. the fibre of the conveyor belt that—upon passing of the belt around the return shaft—is neither loaded with a tensile stress nor with a compressive stress. Preferably, neither a clamping element  47  nor a toothed belt  40  is provided on the outer side of the conveyor belt in order to be able to fully use the width of the belt for objects to be conveyed. 
         [0066]    According to yet a further embodiment (not illustrated), the clamping surface  45  can also be formed as a flank of the toothed belt  40 , so that a widthwise extension of the component part can be reduced. 
         [0067]    As can be seen in  FIG. 3 , the clamping surface  45  of the illustrated embodiment is in contact with a frame-side clamping member. The frame-side clamping member is formed as a clamping roller  81 , which is designed similar to or identical with the idler rollers  81  in this embodiment. The clamping rollers  81  are slightly inclined to apply a radially outward or obliquely upward clamping force to the clamping surface  45  of the clamping element  47 . In this way, the clamping element  47  can tension the conveyor belt  20  radially outwardly. In addition, the backside of the toothed belt  40  or a second tension-bearing member layer  43  arranged between the toothed belt  40  and the idler roller  81  is pressed against the idler roller  80  and thus guided safely between the idler roller  80  and the clamping roller  81 . The idler roller  80  is substantially perpendicular to the conveyor belt plane. Thus, clamping forces are almost exclusively applied via the clamping rollers  81 , disregarding frictional forces on the idler rollers  80 . The width of the conveyor belt can be used optimally due to the perpendicular posture of the idler rollers  80 . 
         [0068]    In  FIG. 3 , below the described clamping roller  81  there is provided an optional second clamping roller  81 , which can serve to tension and guide the returning lower run in the same manner.