Patent Document

BACKGROUND OF THE INVENTION 
     The invention relates to a device for transporting objects along a closed transport track, comprising, as the transport track, two tubular or rod-shaped guide rails, which are arranged parallel to and substantially vertically on top of each other. At least one transport module is connected to each guide rail via at least one support roll pair, wherein the rolls of each support roll pair can be rotated about roll axes which are substantially perpendicular to a guide rail axis and include an angle of less than 180° and the rolls are seated against one of the guide rails in a detent position. The device is equipped with a drive means which is arranged so as to rotate substantially parallel to the guide rails and which can be connected to the at least one transport module. 
     The invention relates to a container conveyor as is frequently used in cartoners. Containers of different sizes are processed in said cartoners by said containers as a rule being shaped, filled, closed and sent on to further production equipment, for example to a palletizer. The most widely varying products from, inter alia, the food, pharmaceutical and health care industry are packaged in such machines. In so doing, different container sizes have to be transported with the container conveyor. 
     The European patent application EP-A-1 215 122 discloses a container conveyor consisting of two parallel toothed drive belts comprising driving dogs, between which the containers are clamped and transported. Upright cartons have to thereby be fed into the transport process via a clock pulse, which time and again leads to malfunctions. The number of containers in transport is fixed due to the regular spacing of the driving dogs, which greatly limits output particularly in the case of small container sizes. This type of conveyor can only be used for filling the containers on account of the lateral access being limited when setting the cartons upright and closing the same. 
     The WIPO patent application WO-A-96/07592 discloses a carton transport device for different carton sizes, comprising three parallel conveyor belts having in each case driving dogs fixed thereon. The transport device can be adjusted for different size cartons in all three dimensions. A substantial disadvantage thereto is the complex mechanical construction of this system and the costs resulting therefrom. The rigid separation of the containers according to size leads to a less flexible system having a fixed number of containers in transport which is independent of the size of the cartons. In addition, tools are required for adjusting the three conveyor belts in relation to one another. As a result, an adjustment at the beginning of the production is likewise again required, which leads to substantially longer times for the renewed start-up of production. 
     The container conveyor known from the WIPO patent application WO-A-2009/077250 is designed as a horizontal rotary conveyor, in which transport modules are fixed to a horizontally rotating chain. Cartons placed on said transport modules are conveyed through the plant and processed at different stations. Only a limited format range (carton sizes) can be covered by the transport modules which are fixedly mounted to the driving means. The construction is not suited to being carried out without the use of tools for the mounting and dismounting of the transport modules which is required for the frequent format changes. 
     A device of the kind mentioned above is disclosed in the European patent application EP-A 0 656 304. In this transport system, transport modules driven by means of a chain are mounted on two parallel guide rails. A substantial disadvantage to this system is that the transport modules cannot be easily exchanged. The transport modules placed onto the guide rails are fastened by means of a screw connection and have to be readjusted after each mounting. 
     SUMMARY OF THE INVENTION 
     The aim underlying the invention is to develop transport modules for a transport system of the kind mentioned above, which can be very easily mounted and dismounted without tools, which automatically compensate for manufacturing tolerances and are also thereby resistant to wear. A further aim of the invention is the automatic compensation for irregularities in the guide rails. The renewed start-up of production after exchanging transport modules should occur in the shortest time as possible. The transport modules should thus be able to be employed without subsequent adjustment. 
     The aim of the invention is met by virtue of the fact that the support roll pairs are non-positively seated against the guide rails via at least one force element, which acts on said support roll pairs and generates a directed force, and by virtue of the fact that at least one of said support roll pairs seated against differing guide rails can be pushed out of the detent position with the guide rail against the acting direction of the force of the force element. 
     The roll axes of the rolls of the support roll pairs preferably include substantially an angle of 90°, and said support roll pairs are preferably mounted to the transport module so that they can rotate about axes which are perpendicular to the guide rail axis and parallel to the vertical axis. By the term “substantially”, an angular deviation of less than 5° is thereby understood. The axes of the support roll pairs which are perpendicular to the guide rail axis and parallel to the vertical axis do not necessarily have to lie along the same axis but can also display a parallel displacement. 
     The support roll pairs seated against differing guide rails are preferably arranged between the guide rails. In so doing, the force exerted by the force element onto one of the support roll pairs is directed away from the force exerted by said force element onto the other support roll pair. 
     The guide rails can, however, also be arranged between the support roll pairs seated against differing guide rails. In this case, the force exerted by the force element onto one of the support roll pairs is directed towards the force exerted by said force element onto the other support roll pair. 
     In an expedient embodiment, the transport module has a vertical module comprising support roll pairs which are arranged on two sides and associated with two differing guide rails. 
     Each of the support roll pairs associated with two differing guide rails can be connected via a respective force element. The module carrier can alternatively consist of two carrier parts connected via a force element. 
     At least one entrainment cam which can be brought into engagement with the drive means, preferably a toothed drive belt, is arranged in a preferable manner on the transport module. 
     Because the distance between the entrainment cam attached to the transport module and the drive means is smaller in a curved segment than in a linear segment, the entrainment cams have to be embodied long enough and in any case be able to penetrate the driving means. The entrainment cam is preferably resiliently attached to the transport module. In so doing, the distance which is subject to change between transport module and drive means can be compensated. 
     The at least one entrainment cam can therefore preferably be displaced in relation to the transport module substantially perpendicularly to the drive means and be brought into engagement with the drive means via at least one force element. In contrast to connecting the transport modules to the drive means via a screw connection, this embodiment facilitates a simple, one-sided decoupling or unhooking of the transport modules from the drive means. In the case of an overload, the cam can decouple from the drive means. This action can prevent damage to the mechanical system. 
     The drive means which is arranged so as to rotate can, for example, be a rotating chain or in particular a toothed drive belt. In a particularly preferable manner, the drive means which is arranged so as to rotate can also be embodied as a rotatably disposed stator of a linear motor. Other drive means familiar to the person skilled in the art are, however, also conceivable. 
     By the term “connectable”, it should be understood in this context that the transport means can be connected non-positively and/or positively to the drive means. The connection can result from a mechanical coupling and/or in particular from a magnetic coupling. 
     In order to compensate for the smaller distance between the at least one entrainment cam and the drive means in a curved segment vis-a-vis a linear segment of a rotary conveyor, the center of the drive means can be displaced with respect to the center of the guide rails by a certain amount away from the curved segment. This displacement can particularly occur parallel to the angle bisector or center parallel of the linear segments which adjoin the curved segment. An additional compensation can take place by means of the aforementioned, resilient attachment of the entrainment cams to the transport module. The distance which varies between transport module and drive means can thus be optimally compensated. 
     The aforementioned resilient entrainment cams are preferably disposed in pairs adjacent to one another. Said entrainment cams disposed in pairs adjacent to one another can thereby be in turn disposed in pairs on top of each other so that in total four entrainment cams are enabled. Said entrainment cams disposed on top of each other can engage, for example, with two drive belts, such as toothed drive belts, disposed on top of each other. 
     Respectively at least two, preferably exactly two, entrainment cams are enabled per mesh point with the drive means. A reliable engagement is thereby achieved at the desired location at the drive means. 
     Further advantages of the invention are:
         shorter downtimes when cleaning the transport modules by means of a simple and fast exchange of said modules,   shorter downtimes during format changes, i.e. change of the transport modules to differing container sizes to be transported,   no tools and no adjustment are necessary when exchanging the transport modules,   compensation for manufacturing irregularities and wear.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages, features and details of the invention ensue from the following description of preferred exemplary embodiments as well as with the aid of the drawings which is only used for explanation and is not to be interpreted restrictively. The drawings show schematically in: 
         FIG. 1  an oblique view of a part of a rotary conveyor system comprising a transport module arranged on guide rails; 
         FIG. 2  a section through the roll system of the transport module from  FIG. 1 , said section being set at a right angle to the guide rails; 
         FIG. 3  the oblique view from  FIG. 1  comprising the section through the roll system pursuant to  FIG. 2 ; 
         FIG. 4  an oblique view of the drive side of the arrangement from  FIG. 1 ; 
         FIG. 5  an oblique view of the partially sectioned entrainment means of the arrangement from  FIG. 4 ; 
         FIG. 6  a section through an alternative roll system of the transport module pursuant to  FIG. 1 , said section being set at a right angle to the guide rails; 
         FIG. 7  an oblique view of a transport module comprising a further roll system which has rolls offset towards the inside and an alternative spring system (leaf springs); 
         FIG. 8  a variant of the relative position of the guide rails with respect to the drive means in a curved region; 
         FIG. 9  a perspective view of an embodiment of entrainment cams for use in the entrainment means depicted in the other figures; 
         FIG. 10  a schematic view from above of the entrainment cam pursuant to  FIG. 9 ; and 
         FIG. 11  a schematic view from above of the entrainment cam pursuant to  FIGS. 9 and 10 . 
     
    
    
     DETAILED DESCRIPTION 
     A transport module  10  reproduced in  FIGS. 1 to 5  is engaged with two guide rails  12 ,  14  of a rotary conveyor system of a packaging machine, which is not illustrated in detail here. The guide rails  12 ,  14  are arranged parallel to and on top of each other and are spaced apart from one another at a distance e. Said guide rails  12 ,  14  are rods or pipes with a circular outer cross-section. Guide rails having another suitable outer cross-section are also conceivable. The transport module  10  includes a central, vertically disposed module carrier  16  comprising carrier parts  18 ,  20  projecting in pairs laterally and horizontally therefrom, said carrier parts being furnished with guiding ducts  22 ,  24  for receiving vertically disposed upper and lower supports  26 ,  28  for upper and lower support roll pairs  46 ,  48 . The upper support  26  overlaps a stepped, cylindrical shaft part  36  of the lower support  28  with a stepped, hollow-cylindrical shaft part  34  while forming a hollow space  38  that is annular in cross-section. A spiral coiled spring  40 , which overlaps the stepped part of the cylindrical shaft part  36  of the lower support  28 , is disposed in the hollow space  38 . The spiral coiled spring  40  is seated at one end against the upper support  26  and at the other end against the lower support  28 . Each support  26 ,  28  ends in the form of a head part  42 ,  44  at an end opposite to the shaft part  34 ,  36 , said head part including the upper and lower support roll pair  46 ,  48  arranged thereon. 
     The rolls of each support roll pair  46 ,  48  are mounted on roll axes a which are at a right angle to each other and project from the head part  42 ,  44 . The supports  26 ,  28  are mounted in the cylindrical guiding ducts  22 ,  24  in the horizontally projecting carrier parts  18 ,  20  and also so as to be rotated relative to each other about a vertical axis z. 
     When the transport module  10  is in the inserted position, the rolls of each support roll pair  46 ,  48  are situated between the two guide rails  12 ,  14  and are seated against the guide rails  12 ,  14  from the inside. The diameter and the spatial position of the rolls of the support roll pairs  46 ,  48  are matched to the outside diameter of the guide rails  12 ,  14  such that the running surfaces of the rolls of the support roll pairs  46 ,  48  are perpendicular to a diametrical plane of the guide rails  12 ,  14 . The spiral coiled spring  40  is preloaded under pressure with a sufficient force; thus enabling the transport module  10  on the one hand to be held sufficiently stable by the support roll pairs  46 ,  48  disposed between the guide rails  12 ,  14  and to be secured against an unintended decoupling and on the other hand to be engaged between the guide rails  12 ,  14  without excessive force being applied by the hand of the operator and to again be removed from the same by the operator lifting the transport module and rotating it out of the guide rails from below. 
     In order to propel the transport module  10 , provision is made pursuant to  FIG. 4  for a toothed drive belt  52 , which is disposed parallel to the guide rails  12 ,  14  and is connected to a drive that is not depicted in the drawing. Two entrainment cams  54 ,  56  disposed vertically on top of each other are arranged on the module carrier  16 . In the example shown, the lower entrainment cam  56  is engaged with the toothed drive belt  52 . The upper entrainment cam  54  is intended for an engagement with a second toothed drive belt, which is not depicted in the drawing, and then, for example, goes into action if the transport speed of the transport module  10  is to be changed at a location of the rotary conveyor system. This change in speed of the transport module can result, for example, by means of the second toothed drive belt being driven slower than the first toothed drive belt  52 . 
     The entrainment cams  54 ,  56  are disposed in a housing  58  which is furnished with opening slots  60  and which is fixed to the module carrier  16 . Said entrainment cams  54 ,  56  have an oblong hole  62  which extends horizontally and in which a stud  64  fixed to the housing  58  engages. Spiral coiled springs  66  preloaded under pressure are disposed between the back wall of the housing  58  and the back side of the entrainment cams  54 ,  56 , said springs pushing the entrainment cams  54 ,  56  away from the module carrier  16  in the direction of the toothed drive belt  52  ( FIG. 5 ). 
     The toothed drive belt  52  is arranged with respect to the guide rails  12 ,  14  such that the entrainment cam  54  is always in engagement with said toothed drive belt  52 , wherein the distance between said toothed drive belt  52  and the transport module  10  is adjusted in such a manner that while being engaged with said toothed drive belt  52 , the entrainment cam  54  lies within the tolerance range predetermined by the end stops of the oblong hole  62  across the entire rotary conveyor system. 
     In the variant to the roll system for a transport module  10  pursuant to  FIG. 1 , which is depicted in  FIG. 6 , the guide rails  12 ,  14  are disposed between the rolls of each support roll pair  46 ,  48  and are seated against the guide rails  12 ,  14  from the outside in the inserted position of the transport module  10 . As is the case in the embodiment shown in  FIG. 2 , the diameter and the spatial position of the rolls of the support roll pairs  46 ,  48  are matched to the outside diameter of the guide rails  12 ,  14  such that the running surfaces of the rolls of the support roll pairs  46 ,  48  are perpendicular to a diametrical plane of the guide rails  12 ,  14 . The spiral coiled spring  40  is connected here at one end to the upper support  26  and at the other end to the lower support  28  and is preloaded under tension with a sufficient force such that the transport module  10  is held on the one hand sufficiently stable on the guide rails  12 ,  14  by the support roll pairs  46 ,  48  together with said guide rails  12 ,  14  that are disposed between the same and is secured against an unintended decoupling. On the other hand, said transport module  10  can be engaged across the guide rails  12 ,  14  and removed from the same without excessive force being applied by the hand the operator. 
     In the transport module  10  depicted in  FIG. 7 , the lower support roll pairs  48  are fixedly mounted to the lower carrier parts  20  of the module carrier  16 . The spacing f of the inner rolls can be reduced with respect to the spacing g of the outer rolls. The rolls are thereby also well guided when the arrangement thereof on the lower carrier part  20  is tight. The upper carrier parts  18  are manufactured from an elastic material and comprise a region  19  of less material thickness opposite to a central part  17 . The spring effect is produced by the elastic material. It is also alternatively possible to produce the spring effect by means of a supporting elastic element. The upper carrier parts  18  are fixed to the module carrier via the central part  17  and a spring plate  72  is placed underneath said upper carrier parts  18 . The spring plate  72  is preloaded under pressure with a sufficient force in the inserted position of the transport module  10  so that said transport module  10  is kept on the one hand sufficiently stable between the guide rails  12 ,  14  by the support roll pairs  46 ,  48  disposed between said guide rails  12 ,  14  and is secured against unintended decoupling, and on the other hand can be engaged between the guide rails  12 ,  14  and removed from the same without excessive force being applied by the hand of the operator. 
     In a curved segment  30  of a rotary conveyor system  50 , the distance between the entrainment cam  56  attached to the transport module  10  and the toothed drive belt  52  is less than in a linear segment  32 . Because the entrainment cam  56  is resiliently attached to the transport module  10 , the varying distance between transport module  10  and toothed drive belt  52  is continually compensated. In order to keep this compensation travel within limits and to minimize a negative effect on the accuracy of the system due to the enlarged leverage effect of too long an entrainment cam, the following action can be taken in the curved segment  30 , in which action the center Z Zr  of the toothed drive belt is displaced with respect to the center Z Fs  of the guide rails  12 ,  14  pursuant to  FIG. 8  parallel to an adjacent linear segment  32  by a specific displacement amount v away from the curved segment  30 . In so doing, the distance of the transport module  10  to the toothed drive belt  52  in the curved segment  30  of the rotary conveyor system  50  is approximately equal to the distance of the transport module  10  to the toothed drive belt  52  in the linear segment  32 . 
     As a function of the type, configuration, size and if required further parameters of the objects provided for transport, a suitable receiving area is mounted on the transport module. In the transport module  10  depicted in the drawings, a mounting plate  68  furnished with boreholes  70  is provided for mounting a receiving area to the central module carrier  16 . 
     A particularly advantageous embodiment of the entrainment cams  54 ,  56  is shown in reference to  FIGS. 9 to 11 . The entrainment cams  54 ,  56  are in this case arranged in pairs adjacent to one another. It can therefore be said that the entrainment cams are enabled in pairs for each mesh point with the drive means, in this case with the toothed drive belt  52 . Each of the entrainment cam pairs  54 ,  56  thereby comprises two entrainment cams  54   a ,  54   b  and  56   a ,  56   b  arranged side by side. The entrainment cams shown in the aforementioned  FIGS. 9 to 11  have basically the same features as those entrainment cams depicted in the preceding figures, in particular the entrainment cams depicted in  FIGS. 4 and 5 . 
     In applications, where the transport modules are transferred to the next station by means of a toothed drive belt  52 , problems can arise when only one single entrainment cam is used. If the tooth gap of the succeeding drive belt is missed when only one entrainment cam is present, the entrainment cam then rests on the tooth of the drive belt and can slip as it is not properly fixed. This is not critical in many applications; however, precisely in those situations where a high degree of accuracy and process reliability are required, the arrangement in pairs is very advantageous. The entrainment cams  54   a ,  54   b  or, respectively,  56   a ,  56   b  have the advantage that a particularly good and most importantly exact engagement in a specific tooth gap  74  or, respectively, in a specific tooth gap pair  74  of a toothed drive belt  52  can be provided. In other words, an arrangement is preferred comprising two entrainment cams  54   a ,  54   b  or, respectively,  56   a ,  56   b , which are spring-loaded independently of one another using resilient means or more specifically spiral coiled springs  66 . 
     With regard to the design of the drive means in the form of a toothed drive belt, it is clear from the figures that said toothed drive belt has a plurality of alternating tooth gaps  74  and teeth  76 . In each case, two adjacent teeth  76  thereby delimit one tooth gap  74 . 
     An embodiment is advantageous in which the entrainment cam  54   a ,  54   b  or, respectively,  56   a ,  56   b  is narrower than the tooth gap  74  of the toothed drive belt as viewed in the direction of rotation. It is thereby ensured that in the case of major irregularities (during the transfer of transport module), at least one of the two entrainment cams is reliably engaged in the toothing or more specifically in the tooth gap  74  of the toothed drive belt and that the transport module is therefore unambiguously positioned. This can be seen clearly in  FIG. 10 , the entrainment cam  54   a  being in this case in connection with the toothed drive belt  52 . The entrainment cam  54   b  abuts in this instance the tooth  76  of the drive belt  52 . Nevertheless, it is ensured here that one of the two entrainment cams, in this instance cam  54   a , engages in the corresponding tooth gap  74  and therefore a transmission of force from the drive belt  52  to the entrainment cams can take place. 
     As is shown in  FIG. 9 , the entrainment cams  54   a ,  54   b ,  56   a ,  56   b , which are arranged in pairs adjacent to one another can thereby in turn be arranged in pairs on top of each other so that in total four entrainment cams  54   a ,  54   b ,  56   a ,  56   b  are enabled. 
     The entrainment cams  54   a ,  54   b  or  56   a ,  56   b  furthermore have each at least one chamfer  78 . The chamfer  78  assists in positioning the corresponding cam. A force from the cam abutting the tooth  76 , here the cam  54   b , is provided by the resilient means  66 ; thus enabling the entrainment cams  54   a ,  54   b  or, respectively,  56   a ,  56   b  to displace relative to the toothed drive belt  52 , whereby it can be ensured that the two entrainment cams  54   a ,  54   b  or  56   a ,  56   b  which are arranged in pairs and adjacent to one another can engage in the corresponding tooth gaps  74 . This is shown in  FIG. 11 . In other words, it can be said that the transport module pushes itself into the correct position on the drive belt by means of the chamfer  78  on the entrainment cam  54   b  that is not yet situated in engagement with the drive belt  52 ; thus enabling both entrainment cams  54   a  and  54   b  to project into the corresponding tooth gap  74  of the drive belt  52 . 
     The entrainment cams  54   a ,  54   b ,  56   a  and  56   b  arranged in pairs are disposed in a housing  58  which is fixed to the module carrier  16  and is furnished with opening slots  60 . As can be seen in  FIG. 5 , the entrainment cams  54 ,  56  comprise an oblong hole which extends horizontally and in which a stud  64  fixed to the housing  58  engages. Spiral coiled springs  66  preloaded under pressure are disposed between the back wall of the housing  58  and the back side of the entrainment cams  54 ,  56 , said springs pushing the entrainment cams  54 ,  56  away from the module carrier  16  in the direction of the toothed drive belt  52  ( FIG. 5 ). 
     In an advantageous manner, the entrainment cams  54   a ,  54   b ,  56   a  and  56   b  are designed narrower than the tooth gap  74 . If the entrainment cam  54   a ,  54   b ,  56   a  and  56   b  now projects into the tooth gap  74 , play is then present between said entrainment cam  54   a ,  54   b ,  56   a ,  56   b  and the drive belt. This is correspondingly shown in  FIGS. 10 and 11 . Said entrainment cams  54   a ,  54   b ,  56   a  and  56   b  are preferably designed narrower than the tooth gap  74  in the region of the engagement area, i.e. in the foremost region. The narrower configuration has the advantage that said entrainment cam  54   a ,  54   b ,  56   a  and  56   b  cannot come to rest on a tooth when engaging in a tooth gap if said gap is not exactly met.

Technology Category: 7