Abstract:
A conveying system to be used in the printing industry, especially in mailroom technology, includes a revolvingly driven conveying member that is provided with supporting elements that are fixed to a traction rope in a stationary and optionally torsion-proof manner. The conveying member can be provided with another rope that has the same length as the traction rope, revolves substantially parallel thereto, and is used as a guide rope or second traction rope. Grippers that are disposed laterally on the belt-shaped conveying member, which is formed by ropes and supporting elements, are arranged on the supporting elements in order to grab and hold individual printed products or groups of printed products. The conveying member is deflected onto different deflection planes via guiding devices while being twisted between such deflections such that the three-dimensional position of the supporting elements and the conveyed printed products can be modified. The guiding devices are equipped with revolving guiding members that are positioned so as to be in contact with the supporting elements.

Description:
BACKGROUND OF THE INVENTION 
     The invention lies in the field of conveyor technology, and relates to a conveyor system according to the preamble of the independent patent claim. The conveyor system serves for conveying printed products, in particular newspapers, magazines, brochures or parts thereof. 
     Known conveyor systems for the application in field of printer&#39;s shops, in particular with regard to mailroom technology, with whose help printed products are to be conveyed in a held manner, are usually chain transporters, thus have a revolvingly driven conveyor member in the form of a chain, on which gripper elements are arranged at regular distances, with which the printed products are gripped and conveyed. A suitable design of the chain, in particular with chain links which are capable of rolling and roll along in a suitable channel, permit the realization of revolving paths or conveyor paths extending in three dimensions with such chain transporters. It is also simply possible with such chain transporters, to convey the printed products conveyed in a held manner, or the gripper elements used for this, in a very accurate sequence. High demands with regard to accuracy are particularly placed on the gripping and the releasing of the printed products by way of the gripper elements and for the processing of the printed products during the conveying. The disadvantages of the chain transporters, as the case may be, lie in the fact that they are relatively expensive, and the distances of the gripper elements on a predefined chain may only be changed in a very restricted manner. 
     In other technical fields, it is counted as belonging to the state of the art, to use conveyor systems based on cables for the conveyor purposes, not only for the relatively large scale transport of humans (cable cars, ski lifts), but also for the small scale transport of articles. In such a conveyor system, carrier elements (chairs, gondolas etc) or catches, which are to be loaded with the people or goods to be conveyed, or to which the persons or goods are to be coupled, are fastened on a pull cable. The cable thereby first and foremost serves as a pull means, but may also simultaneously carry the carrier elements and determine their revolving path. If the cable merely serves as a pull means, then the carrier elements usually comprise runner rollers which roll along on suitable carrier rails determining the revolving path of the carrier elements. Usually, the revolving path of the cable or of the carrier elements runs in a plane, but systems with three-dimensional revolving paths are also known. The carrier elements usually have articulated connections between the cable and the loading region, in a manner such that the loading region always hangs freely from the cable, thus is equally directed relative to gravity, so that the carrier elements always have the same spatial position at regions of the peripheral path, which are directed differently with regard to gravity. 
     One example of a goods conveyor system of the above mentioned type is described in the publication GB-873921. 
     Applications of conveyor systems functioning with a pull cable and carrier elements fastened thereon, in the field of printer&#39;s shops and in particular with regard to mailroom technology are not known. The corresponding tasks, as briefly described above, are usually assumed by chain transporters with grippers. A reason for this is probably the high precision which has likewise been discussed above, and which is necessary with regard to the spatial attitude and position of the grippers or the printed products which are conveyed held by the grippers. The man skilled in the art assumes that such accuracy is very simple to accomplish with a chain transporter. 
     BRIEF SUMMARY OF THE INVENTION 
     It is therefore the object of the invention, to provide a conveyor system which may be applied for the demands in the field of printer&#39;s shops and in particular with regard to mailroom technology, in a very flexible manner, wherein this conveyor system may not only attain the required accuracy in the same manner as the known chain transporters, but may master the required flexibility better than the chain conveyor. The conveyor system according to the invention should therefore not only be suitable to be set up for the most different of conveyor tasks, but it should also be suitable to accomplish such different conveyor tasks at different locations of a single revolving path in an essentially simultaneous manner. Despite this, the conveyor system according to the invention should be simple in manufacture and in operation. 
     This object is achieved by the conveyor system as is defined in the patent claims. 
     The conveyor system according to the invention, as with the initially mentioned conveyor systems known from other fields of technology, comprises a revolvingly driven conveyor member, which consists essentially of a pull cable and a plurality of carrier elements. The carrier elements are equipped for a positionally fixed and, if required, a rotationally secured fastening on the pull cable, and they each carry a gripper at their one end. The grippers are suitable for carrying individual printed products or of larger or smaller groups of printed products. The ends of the carrier elements equipped with the grippers, given an untwisted pull cable, project away from the pull cable in the same direction, which means that the carrier elements are aligned to one another and the grippers are arranged in a row essentially parallel to the pull cable. The carrier elements are not only pulled, but also carried by the pull cable. The pull cable is slightly tensioned for this. 
     The conveyor system according to the invention preferably comprises a further cable additionally to the pull cable, and this further cable is essentially equally long as the pull cable and revolves essentially parallel to this, and may serve as a guide cable or as a further pull cable, and in any case, guides and holds the carrier elements in their position aligned to one another. If the further cable is designed as a guide cable, the carrier elements are only loosely fastened thereto, and are only held in the position aligned to one another by the guide cable. If the further cable is to serve as a second pull cable, the carrier elements are fastened thereon as on the first pull cable. In both cases, the two cables together with the carrier elements form a stable, belt-like revolving conveyor member, on whose one narrow side the grippers are arranged in a row. Of course, the conveyor system according to the invention may also comprise more than two cables, of which at least one serves as a pull cable, which means that the carrier elements are fastened or may be fastened on at least one of the cables in a positionally fixed manner. 
     The conveyor system according to the invention may also comprise only the pull cable and no further cable. In this case, the carrier elements are not only fastened or fastenable on the pull cable in a positionally fixed manner, but also in a rotationally secured manner. 
     The conveyor system according to the invention further comprises at least one drive, and guide means which are arranged along the revolving path and by way of which the revolving path of the conveyor member is generally defined, which particularly also means the revolving path of the grippers and thus also the course of the conveyor path along which printed products held by the grippers are conveyed. The grippers are closed and opened for gripping and releasing printed products. 
     The revolving path of the conveyor member in the conveyor system according to the invention is in particular a three-dimensional formation, wherein the guide means deflect the conveyor member in different planes, and in particular in planes which are not parallel to one another. The conveyor member is twisted between such deflections, in a manner such that the carrier elements relative to the deflection plane are always directed equally, in particular perpendicularly to the deflection plane, so that guide means functioning according to the same principle may be applied for the deflections independently of the position of the deflection planes, said guide means preferably engaging neither on the pull cable nor on the further cables, but on the carrier elements. Further guide means functioning according to the same principle may be applied, in order not to deflect the conveyor member, but to create twists on straight-lined regions of its revolving path, or by way of such twists, to bring the carrier elements and in particular the grippers arranged thereon or the printed products held by these, into a predefined position, e.g. for the gripping, releasing or the processing of printed products held by the grippers. If the conveyor member only comprises the pull cable and no further cable and is significantly less stable than a conveyor member with one or more cables by way of this, it may then be advantageous to also apply guide means functioning according to the same principle, also on straight-lined revolving path regions without any twisting, thus merely for stabilizing the conveyor member. 
     Selected guide means may also assume a drive function additionally to their guiding function. 
     Evidently, the guide means of the system according to the invention play a very central role. They are not only applied where a change in direction (deflection) in the revolving path is to be realized, but also where the conveyor member is to be twisted without a change in direction or is only to be stabilized. As already mentioned, preferably it is always the same type of guide means which is used for the different guide functions, wherein this guide means type is to be as independent as possible of the distance of the carrier elements on the pull cable, so that it may be used in an unchanged manner in conveyor systems or regions thereof, which are provided for the most varied of conveyor functions. These guide means, as already mentioned, preferably engage not on the pull cable or on further cables, but on the carrier elements, and specifically offset with respect to the pull cable and the further cables, and on the one side or on two opposite sides of the carrier elements, depending on the guide function. The parts of the guide means contacting the carrier elements are revolving guide members, in particular revolving guide belts or guide chords. Of course, the conveyor system according to the invention may also comprise other types of guide means, additionally to the mentioned preferred type of guide means, or of drives combined with guide means. 
     The connection between the carrier element and the pull cable may be rigid, wherein the carrier elements are then preferably fastened at regular distances to one another along the pull cable. The connection between the carrier element and the pull cable may however also be releasable, in a manner such that the pull cable continues to act as a guide cable when the connection is released, or in a manner such that the carrier element may be completely decoupled from the pull cable. If the pull cable acts as a guide cable when the connection of the carrier elements is released, then for example in this condition, the distances between the carrier elements may be varied during the conveyor operation, and the carrier elements may also stand still relative to the pull cable and for example be buffered. 
     The carrier elements may be equipped with the most varied of grippers for gripping, holding and releasing printed products. Essentially, all types of known such grippers may be applied, as well as essentially all control means which are known for the opening and closure of such grippers. The grippers grasp the printed products in the manner known per se, in the region of an edge. This edge may be aligned parallel to the conveyor direction, wherein the distances of the gripper is of such a size, that each gripper grips a printed product, and these are conveyed overlapping one another and one after the other. It is however also possible, with grippers or carrier elements arranged suitably closer to one another, to provide an imbricate flow, wherein each gripper grips a plurality of products overlapping one another, and each product is held by a plurality of grippers. The product edges gripped or to be gripped by the grippers may also be aligned transversely to the conveyor direction, so that the printed products are aligned in a compacted flow one after the other and essentially aligned on one another. Of course, it is possible to arrange the grippers on the carrier elements in a tiltable, pivotable or rotatable manner, wherein control means are provided at predefined locations of the revolving path, by way of which certain tilt-positions, pivot positions or rotation positions may be set and/or maintained at predefined locations of the revolving path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary, preferred embodiments of the conveyor system according to the invention are described in detail by way of the following figures. With this, they are shown in: 
         FIG. 1  is a perspective view of one exemplary embodiment of the conveyor system according to the invention, said embodiment comprising deflection wheels deflecting the conveyor member in different planes; 
         FIG. 2  is a cross-sectional elevation view of a deflection by way of deflection wheel of the conveyor system according to  FIG. 1  (section parallel to the axis of the deflection wheel, section line II-II in  FIG. 1 ); 
         FIG. 3  is a perspective view of a twist location of the conveyor system according to  FIG. 1 , in a larger scale; 
         FIG. 4  is a cross-sectional elevation view of an exemplary gripping location or release location of the conveyor system according to  FIG. 1  (section parallel to the axis of the deflection wheel, section line IV-IV in  FIG. 1 ); 
         FIG. 5  is a perspective view of a further guide means which may be used in a conveyor system according to  FIG. 1 ; 
         FIG. 6  is a perspective view of a guide means as in  FIG. 5 , applied in a conveyor system with only one pull cable; 
         FIG. 7  is a perspective view of a further guide means, applied in a conveyor system with only one pull cable, wherein the conveyor member is twisted and supported by the guide means, but not deflected; 
         FIG. 8  is a cross-sectional elevation view of section line VIII-VIII in  FIG. 7 , sectioned transversely to the conveyor direction; 
         FIG. 9  is an elevation view of a buffer stretch of the carrier elements; 
         FIG. 10  is an elevation view of the carrier element in section parallel to the pull cable in the condition fastened on the cable, and in the condition released from this; 
         FIG. 11  is an elevation view of the carrier element in section parallel to the pull cable in the condition fastened on the cable, and in the condition released from this; 
         FIG. 12  is an elevation view of the carrier element in a section transversely to the pull cable; 
         FIG. 13  is an elevation view of a buffer stretch of the carrier elements; 
         FIG. 14  is an elevation view of the carrier element sectioned partly parallel to the pull cable; 
         FIG. 15  is an elevation view of a further exemplary embodiment of carrier elements which may be applied in the conveyor system according to the invention, with releasable connection to the pull cable, in a manner such that the carrier elements may be decoupled from the pull cable and may be fastened on another pull cable (four consecutive stages of a transfer from one pull cable to the other pull cable); 
         FIG. 16  is an elevation view of the carrier element in the condition coupled on the pull cable; and 
         FIG. 17  is an elevation view of the carrier element in the condition decoupled from the pull cable and guided in a guide channel). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a very schematic representation of a first, preferred embodiment of the conveyor system according to the invention, of which only one part which is of relevance to the conveying is represented. The conveyor system comprises two equally long, closed cables  1 . 1  and  1 . 2  which are in each case closed into an endless loop and which are driven in a revolving manner at the same speeds essentially parallel to one another, and together with the carrier elements  2 , form an endlessly revolving, belt-like conveyer member  1 , on which the grippers  2  are arranged laterally in a row. At least one of the cables, preferably the cable  1 . 1  further distanced from the grippers, serves as a pull cable which means that the carrier elements are fastened thereon in a positionally fixed manner. 
     The carrier elements  2  which are not all shown in  FIG. 1 , are fastened on the pull cable  1 . 1  at regular distances, and are in each case equipped with a gripper  3  arranged laterally of the belt-like conveyor member. The revolving path of the conveyor member  1  is defined by guide means  4 , which in the shown case are designed as freely rotating deflection wheels  5 , wherein a plurality of guide members  6 . 1  and  6 . 2  revolving with the rotating deflection wheels  5 , are arranged around the periphery of each deflection wheel  5 . The conveyor member  1  with the carrier elements  2  is deflected by the deflection wheels  5  in different planes (three planes perpendicular to one another in the represented case), and is forcibly twisted at twist locations  7  between deflections in different planes. 
     If the friction between the guide members  6 . 1  and  6 . 2  and carrier elements  2  is adequately large, then one of the deflection wheels  5  may also be designed as a conveyor drive, which means it is not mounted in a freely rotating manner, but suitably driven in a rotating manner. A chain wheel with teeth (not shown) may also be applied, for example as a conveyor drive, wherein the teeth engage into the belt-like conveyor member  1 , between the cables  1 . 1  and  1 . 2  and between adjacent carrier elements  2 . 
     The conveyor system according to  FIG. 1  is designed for conveying an imbricate flow  10  in the conveyor direction F, wherein printed products  11  are arranged overlapping one another in the imbricate flow  10 . The imbricate flow  10  is gripped by the grippers  3  of the carrier elements  2  in a gripping location  12  and are released in a releasing location  13 , wherein the distances of the grippers  3  on the belt-like conveyor member  1  and the length of the products  11  and their overlapping in the imbricate flow  10  are for example matched to one another such that each gripper  3  grips a plurality of products  11  overlapping one another, and each product  11  is held by a plurality of grippers  3 . In this manner, the imbricate flow  10  is held and conveyed as a whole. Control means  15  are arranged at the gripping location  12  and at the releasing location  13 , with which the grippers for gripping are opened as the case may be, and closed again; and for the release are opened and are closed again, if required. 
       FIG. 2  in a larger scale, shows a section (section line II-II in  FIG. 1 ) through one of the deflection wheels  5  represented in  FIG. 1 , as well as a carrier element  2  which is fastened on at least one of the cables  1 . 1  and  1 . 2 , and is conveyed about the deflection wheel  5 . The carrier element  2  is equipped with an exemplary gripper  3 , wherein the gripper  3  is closed about one edge of a printed product  11 . The deflection wheel  5  is rotatingly mounted freely about an axis A, or, if its serves as a conveyor drive, is also rotatingly driven about this axis A. 
     The represented carrier element  2  comprises two clamping parts  2 . 1  and  2 . 2 , which at their oppositely directed sides comprise inner grooves  20 . 1  and  20 . 2  which are aligned to one another, are matched in their cross section to the cables  1 . 1  and  1 . 2 , and together in each case form an opening for the cables  1 . 1  and  1 . 2 , which leads through the carrier element  2 . The clamping parts  2 . 1 ,  2 . 2  are clamped against one another with suitable, non-shown clamping means, in a manner such that the carrier element  2  is fastened in a positionally fixed manner on at least one of the cables  1 . 1 ,  1 . 2  by way of the clamping effect. Furthermore, the clamping parts  2 . 1  and  2 . 2  comprise outer grooves  21 . 1  and  21 . 2  which run parallel to the inner grooves  20 . 1  and  20 . 2 , and are adapted to the revolving guide members  6 . 1  and  6 . 2  of the guide means  4 . The revolving guide members  6 . 1  and  6 . 2  in the present case are designed as chords which are arranged in corresponding grooves  22 . 1  and  22 . 2  running around the periphery of the deflection wheel  5 . 
     In order for the carrier elements  2  to be able to be deflected in different directions by way of equal guide means, both clamping parts  2 . 1  and  2 . 2  comprise outer grooves  21 . 1  and  21 . 2 , as this is shown in  FIG. 2 . In order for the carrier elements  2  to be able to be applied in an as comprehensive as possible manner, these preferably comprise a third inner groove  20 . 3 , which is arranged centrally between the two outer grooves  21 . 1  and  21 . 2 , and in the embodiments of the conveyor system according to the invention, are used with only one cable (see  FIGS. 6 to 8 ) for receiving the cable. Whilst it would be evidently possible in the represented case of a conveyor system with two cables, to provide a guide wheel  5  with only one revolving guide member and to arrange this for a contact with the carrier elements between the two cables, in the case of the conveyor system with only one cable, it is necessary for two revolving guide members to be provided. Of course, it is also possible to provide further cables and/or further revolving guide members and corresponding grooves in the clamping parts  2 . 1  and  2 . 2 . 
       FIG. 3 , again in an enlarged scale, shows a twist location  7  of the conveyor system according to  FIG. 1 , which for example occurs between a deflection wheel  5  with a vertical axis (deflection plane horizontal) and a deflection wheel  5  following this, with a horizontal axis (deflection plane vertical). The same elements are indicated with the same reference numerals as in  FIG. 1 . The carrier elements  2  are the same as those in  FIG. 2 . The clamping means, with which the two clamping parts  2 . 1  and  2 . 2  of the carrier elements  2  are clamped about the cables  1 . 1  and  1 . 2 , are screws  25  which are engage from one clamping part into the other clamping part, and which are arranged in the region of the cable  1 . 1 . By way of this, a larger clamping force around the cable  1 . 1  than around the cable  1 . 2  results (with equally designed inner grooves), in a manner such that the holding elements  2  are fastened on the cable  1 . 1  in a positionally fixed manner and render this a pull cable, whilst they likewise encompass the cable  1 . 2 , but are somewhat movable relative thereto, and this cable becomes a guide cable due to this. 
     It is evident from  FIG. 3  that in the twist location  7 , not only is the relative spatial position of the two cables  1 . 1  and  1 . 2  changed, but also the spatial position of the carrier elements  2  and thus also the spatial position of the printed products  11  held by the grippers  3 . 
       FIG. 4  shows a section (section line IV-IV in  FIG. 1 ) through the deflection wheel  5  of the gripping location  12  ( FIG. 1 ), as is represented in  FIG. 1 . The same elements are again indicated with the same reference numerals. The gripping location  12  lies in the region of the lower apex point of the deflection wheel  5 . The grippers  3  (designed somewhat differently than the gripper represented in  FIG. 2 ), in the opened condition ( 3 . 1 , dot-dashed), run into the gripping location  12 , and are closed at the gripping location, in order to grip a lateral edge of the imbricate flow  10 , which for example is conveyed on a conveyor belt  30  into the gripping location  12 . The gripper  3  in the closed condition is indicated at  3 . 2  and is represented unbroken. Control means (e.g. a stationary cam) which are not shown, for opening the grippers  3 , for example engages on cam wings  32  connected to the gripper jaws  31 , and drive the gripper jaws  31  against the clamping force of a spring  33  into a position distanced to one another (gripper open). The spring  33  closes the gripper  3  which thus grips the edge region of the imbricate flow  10 , when the action of the control means is ceased. 
       FIG. 5  shows a further exemplary guide means  4  or deflection means, which may be applied in a conveyor system according to  FIG. 1 . In contrast to the deflection wheels  5  of  FIG. 1 , the two revolving guide members  6 . 1  and  6 . 2  of the guide means  4  according to  FIG. 5  are not arranged around the periphery of the wheel, but they run over a plurality of rollers  40  mounted in a freely rotating manner, wherein the rollers  40  are arranged in a curve and on their periphery comprise runner channels  41  adapted the revolving guide members  6 . 1 ,  6 . 2 . Preferably, the guide means  4  also comprises a resiliently mounted roller  40 . 1  serving as a tension roller. If the guide means  4  according to  FIG. 5  is also to function as a conveyor drive, then it additionally comprises a roller  40 . 2  designed as a drive roller, which is rotatingly driven by its own drive  42 . In order for the slip between the drive roller  40 . 2  and the guide members  6 . 1  and  6 . 2  to be kept as small as possible, it is advantageous to arrange the rollers  40  and  40 . 1  in a manner such that the wrapping of the drive roller  40 . 2  by the guide members  6 . 1  and  6 . 2  is as large as possible. 
       FIG. 6  shows an equal guide means  4  as in  FIG. 5 , which however is applied in a conveyor system with only one pull cable  1 . 3 . The carrier elements  2  are the same as those described in connection with  FIG. 2 , wherein the single cable  1 . 3  runs through the middle inner grooves  20 . 3  of the clamping parts  2 . 1  and  2 . 2  of the carrier elements  2 . 
       FIGS. 7 and 8  show further, exemplary guide means  4 , which do not effect a deflection of the conveyor member  1 , but only a twisting of the conveyor member  1 . These guide means  4  consist of two guide means parts  4 . 1  and  4 . 2  which engage on opposite sides of the carrier element  2  and which are designed in essentially the same manner as the guide means described in combination with the  FIGS. 5 and 6 . FIG.  7  shows the guide means in a three-dimensional representation,  FIG. 8  in a section perpendicular to the conveyor direction (section line VIII-VIII in  FIG. 7 ). 
     The two guide means parts  4 . 1  and  4 . 2  again, in each case comprise the two revolving guide members  6 . 1  and  6 . 2 , which in the present case each run over two rollers  40 . The axes of the rollers  40  are all arranged at the same distance to the carrier elements  2  parallel to one another and perpendicularly to the conveyor direction, so that the conveyor member  1  which is guided between the guide members running over the rollers  40 , is not deflected but only twisted. The carrier elements  2  are the same as the carrier elements described in the context of  FIG. 2 . One may particularly deduce from  FIG. 8 , that it makes essentially no difference as to whether the conveyor member comprises one cable or two cables. 
     The conveyor member  1  for example runs with vertically aligned carrier elements  2  against the guide means  4  (for example from a deflection in a horizontal plane), and is twisted by the guide means  4 , in a manner such that the carrier elements  2  are rotated into a horizontal position. Evidently, it is also possible to arrange the guide means parts  4 . 1  and  4 . 2  in a manner such that the guide member is not twisted, but is held and stabilized in a position which it has already before running into the guide means  4 . In this manner, this position is held in a precise manner, which may be particularly important for conveyor members with only one cable, since these may be twisted already by way of very small side forces, and thus may advantageously be guided at locations, at which an exact positioning of the grippers  3  is necessary. 
     It is evident from  FIGS. 1 to 8 , that with the use of one of the shown guide means  4  as a conveyor drive, the conveyor system may be operated in two opposite directions, and the operation is essentially independent of the distance of the carrier elements  2  in the conveyor member  1 . This distance may thus be adapted to the respective use, and to characteristics of the printed products to be conveyed, without other system parts having to be used on account of this. If, for a specific application, such a large distance between the carrier elements  2  should be necessary, that the cable or the cables are kinked too much with deflections before and after a carrier element, or that the cable or the cables come into undesired contact with parts of guide means  4 , between the carrier elements in deflections, so-called blind carrier elements without grippers also may be integrated in the conveyor member between the conveying carrier elements, thus those equipped with grippers. 
     In particular, wire cables with a diameter of approx. 5 mm or less are applied as cables  1 . 1 ,  1 . 2  or  1 . 3 . It has been shown that carrier elements for the usual loads in the mentioned field of technology may not only be fastened in a positionally fixed manner, but also in a rotational fixed manner on such cables without further clamping. The advantage of the embodiments with more than one cable lies in the fact that the belt-like conveyor member has a greater twisting stiffness. The advantage of the embodiment forms with only one cable lies in the fact that apart from the guide means  4  described above, for deflecting the conveyor member, one may also apply other, for example cog-like deflection means, by way of which deflections with carrier members directed parallel to the deflection plane, and grippers which are spread apart on account of this, are possible, which entails an even greater flexibility. 
       FIGS. 9 to 14  shows further embodiments of carrier elements  2  which may be applied in the conveyor system according to the invention. These carrier elements  2  are releasably fastened on a pull cable  1 . 3 , in a manner such that the pull cable  1 . 3  may no longer pull but still guide the carrier elements  2  given a released fastening, so that the carrier elements  2  are slidable along the cable  1 . 3 , or the carrier elements  2  may stand still, whilst the cable  1 . 3  revolves. The distances of the carrier elements  2  from one another may also be set during the conveyor operation by way of temporarily releasing the fastening.  FIGS. 9 and 13  show an exemplary application of such carrier elements  2  releasably fastened on the pull cable  1 . 3 , specifically a buffer stretch  50  on which carrier elements  2  are dammed and are released again in a controlled manner, for example in a regularly cycled manner. 
     The carrier elements  2  of  FIGS. 9 to 12  comprise a continuous opening  51  for the cable  1 . 3 , and which for example is formed by inner grooves aligned to one another, in two clamping parts, similarly to the carrier elements discussed in combination with  FIG. 2 . Thereby, the grooves however are dimensioned in a manner such that the opening  51  has an inner cross section which is larger than the cable cross section, thus the cable may run through the opening in a loose manner. Additionally, a clamping device, for example a clamping spring  52 , is arranged in the opening  51 , and is sufficiently biased against the cable, in order to be able to firmly hold the cable in the opening  51  is a positionally fixed and, as the case maybe, rotationally secured manner. A control element  53  actively connected to the clamping device projects from the opening  51  out of the carrier element  2 , via which control element  53 , the clamping effect of the clamping spring  52  may be lifted or reactivated in a controlled manner. The control element  53 , as represented in the  FIGS. 9 to 12 , is for example a control lever  54  with a control slide  55  or control roller which slide or roll on a suitable cam  56 , in a manner such that the clamping spring  52  is lifted by the control lever  54  from the cable  3 . 1  by its own spring force, when the connection between the cable  1 . 3  and the carrier element  2  is to be released. Simultaneously, the control element  53  and the cam  56  may be used in order to maintain the rotation position of the carrier elements  2  on the cable  1 . 3 , or to change it in a controlled manner, whilst the clamping spring  52  is held in its inactive position. 
     The buffer stretch  50  represented in  FIG. 9  comprises a stop  57 , which for example in a regularly cycled manner, projects into the conveyor path of the carrier elements  2  or is removed from this (double arrow S). The cam  56  is arranged behind the stop  57  in the conveyor direction F, by way of which cam the connection between the carrier elements  2  which are conveyed against the stop  57 , and the cable  1 . 3 , is kept released. The carrier elements  2  are then conveyed by an individual drive, which may be gravity with a dropping conveyor path, against the stop  57  and the carrier elements dammed by this. If the stop  57  releases a carrier element  2 , then this leaves the region of the cam  56  and by way of this, is again fastened on the cable  1 . 3  and conveyed further, whilst the loose carrier elements  2  follow on against the stop  57 . 
     For illustration of the clamping device by way of clamping springs  52  described above,  FIGS. 10 and 11  show a carrier element  2  according to  FIG. 9  sectioned parallel to the cable  1 . 3 , fastened on the cable and in the condition released from the cable, and  FIG. 12  shows the same carrier element  2  sectioned transversely to the cable  1 . 3 . 
       FIGS. 13 and 14  show a further carrier element  2  which is released from the pull cable  1 . 3  and is led through the pull cable in the released condition. The connection between the carrier element  2  and the cable  1 . 3  is again controllable via a control element  53  in a manner not represented in more detail, wherein the control element  53  is activated by a carrier element  2  which runs in front and which is already released from the cable, and is thus moved more slowly or stands still. One may realize buffer stretches  50  of an infinite length with carrier elements  2  equipped in such a manner, whilst the buffer stretch according to  FIG. 9  may not be longer than the length over which the connections between the carrier element  2  and cable  1 . 3  may be held in a released manner by the cam  56 . 
     In this context, it is possible for the man skilled in the art, without further ado, in this context, to adapt the carrier elements  2  and their releasable fastening on the cable  1 . 3 , as they are represented in the  FIGS. 9 to 14 , to applications with more than one cable and for other applications, which are thus not buffer stretches. 
       FIGS. 15 to 17  show carrier elements  2 , whose fastening on the pull cable is not only releasable, but which may be completely decoupled from the cable. The same figures also show exemplary applications for such carrier elements. 
     The carrier elements  2  according to  FIG. 15  may be transferred from a first cable  1 . 4  to a second cable  1 . 5 , wherein, fastened on the first cable  1 . 4 , they are conveyed into a transfer location (condition a), and in the transfer location in which the two cables  1 . 4  and  1 . 5  are led parallel next to one another, are fasted on the second cable  1 . 5  (condition b), and then decoupled from the first cable  1 . 4  (condition c). After the transfer location, the carrier element  2  is led away fastened on the second cable  1 . 5  (condition d). In order to permit the mentioned transfer, the carrier element function is for example distributed to three separate elements which are essentially independent of one another, specifically to two fastening parts  60 . 1  and  60 . 2  which are assigned in each case to one of the cables  1 . 4  and  1 . 5  and are rigidly or releasably fastened on this, and to carrier part  61 , which carries the gripper  3  and which may be selectively coupled to the one or the other fastening part  60 . 1  or  60 . 2 , for example, as represented in  FIG. 15 , by way of suitable clamping means  62  ( 62 . 1  clamping means in deactivated condition,  62 . 2  clamping means in the activated condition) which may be activated and accordingly activated again via a control means (e.g. cam  56 ). 
     Of course, it is also possible to design the clamping means for a direct fastening to the first and the second cable  1 . 4  and  1 . 5 , instead of providing separate fastening parts for this for the fastening on the cables  1 . 4  and  1 . 5 , as is the case in  FIG. 15 . 
       FIGS. 16 and 17  show a further embodiment of carrier elements  2  which may be decoupled from the pull cable  1 . 3  and which are provided with runner rollers  71  on its side lying opposite the gripper  3 , for guiding in a guide channel  70 . A pivotable clamping lever  2 . 3  is provided for fastening on the pull cable  1 . 3 , and this lever with a cam roller  72  which runs on a cam which is not shown and by way of which the pivotable clamping lever is applied around the cable (carrier element fastened on the cable,  FIG. 16 ) or is distanced to this (carrier element released from the cable and may be decoupled or is decoupled,  FIG. 17 ). 
       FIG. 16  shows the leading of the carrier element  2  against a deflection, in which the cable  1 . 3  is deflected to the left. Before the deflection of the cable, the guide channel  70  runs parallel to the cable  1 . 3 , and the runner rollers  71  run in the channel  70 . This condition is shown in  FIG. 16 . Between the run-in of the runner rollers  71  into the channel  70 , and the cable deflection, thus with a still parallel guiding of the cable  1 . 3  and the guide channel  70 , the fastening of the carrier element  2  on the cable  1 . 3  is released (clamping lever  2 ,  3  pivoted up, on the left in  FIG. 17 ) and the carrier element  2 , as soon as it comes onto a region in which the cable  1 . 3  and the guide channel  70  no longer run parallel (on the right in  FIG. 17 ), is decoupled from the cable  1 . 3 . 
     A coupling onto the cable runs essentially in a reverse manner to the decoupling described above. 
     The above description and the figures clearly show that very many different conveyor tasks may be solved with the conveyor system according to the invention. Thereby, the cables, the carrier elements and the guide means may be joined together in a modular manner into the most different of conveyor systems, and/or one may realize conveyer paths with the carrier elements which are releasable or may even be decoupled from the pull cable, on which the most different of conveyor tasks are solved one after the other.