Abstract:
A conveyor installation for the transportation of articles along a predefined path includes a running rail, at least one running carriage which is freely movable along the running rail, and a driven engagement device which extends at least in sections along the running rail and which includes a multiplicity of engagement elements movable along the running rail. Reliable and quiet operation is achieved in that the engagement elements are movable back and forth between two stable positions, wherein, in the first stable position, the engagement elements can be moved relative to the at least one running carriage past the running carriage without entering into engagement with the running carriage (non-engagement position), and wherein, in the second stable position, the engagement elements, during a movement relative to the at least one running carriage past the running carriage, compulsorily enter into engagement with the at least one running carriage (engagement position).

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    The present invention relates to the field of conveyor technology. It relates to a conveyor installation as per the preamble of claim  1 . 
       Discussion of Related Art 
       [0002]    For the automatic conveyance of articles, such as for example items of clothing suspended on hangers, along rails led through a space, the prior art has disclosed a multiplicity of systems which fall under the term “Power and free” and which are distinguished by the fact that the articles suspended on running carriages are moved forward by drivers which run in parallel and which are driven and which are in engagement and which, if the running carriage encounters an obstruction, automatically pass out of engagement and are moved past the stopped running carriage. 
         [0003]    Document DE 10 2005 006 455 A1 discloses a transport system for suspended articles, in particular for items of clothing suspended on hangers, having a transport rail, having a drive chain which is arranged so as to be movable in a conveying direction in the transport rail and which has downwardly projecting drivers, and having holding elements for the articles, which holding elements are mounted in the transport rail, below the drive chain, by way of running rollers and which are movable in the conveying direction by way of the drive chain. The transport system is distinguished by the fact that the drivers are of bolt-like form, in that the holding elements are mounted in the transport rail in pendular fashion only about one pair of rollers and have upwardly protruding projections for engaging into the drive chain between two adjacent drivers, and in that, between the transport rail and the holding elements, there are provided means which prevent projection and driver from passing out of engagement in the presence of a predefined maximum inclination of the holding element relative to a normal with respect to the transport rail in a vertical transport plane spanned by the conveying direction. 
         [0004]    Document DE 10 2011 119 411 A1 discloses a retroactively installable stopper unit for a suspended conveyor, which stopper unit transports a pawl-type driver, in an at least unilaterally open slot of a support rail on which hangers are transported in sliding fashion by way of pawl-type drivers, downstream in a conveying direction which is oriented parallel to the longitudinal direction of the support rail. The stopper unit comprises a guide which is fastenable to the suspended conveyor, a carriage which has an abutment section, wherein the carriage is, by way of the guide, mounted so as to be movable preferably linearly in a transverse direction which is oriented transversely with respect to the longitudinal direction; and a drive which is coupled to the carriage and which is designed such that, during the activation thereof, said drive deploys the carriage from a release position, in which the abutment section of the carriage does not project beyond the rail, such that the hangers can pass by the carriage, along the transverse direction into a stop position, in which the abutment section projects beyond the support rail, preferably over the entire width thereof, wherein, when the drive is activated, in the event of a force acting in the transverse direction, the carriage can be retracted into the release position, and in the event of a force acting exclusively in the longitudinal direction, the carriage remains in its present position. 
         [0005]    The document DE 203 17 972 U1 describes a suspended conveyor installation having a conveyor rail, having a driveable conveyor device which is arranged above the conveyor rail, having pawl-type drivers which are attached to the conveyor device and which are oriented relative to the conveyor rail and which serve for transporting hanger hooks, which are situated displaceably on the conveyor rail, in a conveying direction, wherein each pawl-type driver has a carrier connected to the conveyor device and has a pawl, which pawl has a driver hook which follows in the conveying direction and which pawl is hinged at the carrier by way of a pivot spindle which is arranged laterally with respect to and above the conveyor rail and at an acute angle (d) of at most 60° with respect to the conveying direction. The document U.S. Pat. No. 6,367,612 B1 discloses an extendable driver for an overhead accumulating conveyor system (“power and free”) which comprises a body section composed of a rectangular cylinder which is equipped with a spring and slider element within the cylinder. If a force greater than the static spring force acts on the slider element, the slider element retracts into the body section, such that the structural height of the driver is reduced. Owing to its automatic retraction, the retractable driver does not require any modification to the driven and free rails or to the running carriages. 
         [0006]    All known systems operate with engagement configurations which are duly released when an obstruction is encountered but which then retract again into a stable engagement basic position. Owing to this “monostable” mode of operation, the use of the known systems is restricted. Furthermore, the monostable mode of operation is associated with considerable noise generation, for example because, when a stopped running carriage is “passed over” by the successive drivers which are in each case deflected and retract into their initial state again, a rattling noise is generated. 
       SUMMARY OF THE INVENTION 
       [0007]    It is therefore an object of the invention to specify a conveyor installation which makes it possible to realize greater flexibility and quiet operation. 
         [0008]    These and further objects are achieved by way of the features of claim  1 . 
         [0009]    Refinements of the solution according to the invention will emerge from the dependent claims. 
         [0010]    The conveyor installation according to the invention for the transportation of articles, in particular goods, along a predefined path comprises a running rail and comprises at least one running carriage which runs on said running rail and which is freely movable along the running rail, and furthermore comprises a driven engagement device which extends at least in sections along the running rail and which comprises a multiplicity of engagement elements which are movable along the running rail and which, for the purposes of controlling the movement of the at least one running carriage, can be placed in engagement with the running carriage. 
         [0011]    Said conveyor installation is distinguished by the fact that the engagement elements are movable back and forth between two stable positions, wherein, in the first stable position, the engagement elements can be moved relative to the at least one running carriage past the running carriage without entering into engagement with the running carriage (non-engagement position), and wherein, in the second stable position, the engagement elements, during a movement relative to the at least one running carriage past the running carriage, compulsorily enter into engagement with the at least one running carriage (engagement position). 
         [0012]    One refinement of the conveyor installation according to the invention is characterized in that the engagement elements are, in the engagement device, arranged one behind the other, and so as to be spaced apart uniformly from one another, in the movement direction. 
         [0013]    One refinement of the conveyor installation according to the invention is characterized in that the engagement elements are in each case mounted so as to be pivotable about a swivel axis, and can be moved from one stable position into the other by way of a pivoting movement about the swivel axis. 
         [0014]    In particular, the engagement elements each lock with detent action in the two stable positions. 
         [0015]    In particular, the detent position of the engagement elements in the second stable position is configured such that the detent position of one engagement element is eliminated and the engagement element is pivoted into a first stable position if a force acting counter to the movement direction and of a predetermined magnitude acts on said engagement element. 
         [0016]    In particular, the engagement elements, during the pivoting, move in each case along a detent element which is static relative to the swivel axis, and in the two stable positions, each lock with detent action, by way of a recess, at the detent element. 
         [0017]    In particular, the detent element is in the form of a detent bolt oriented parallel to the swivel axis, and the recesses on the engagement element are in the form of detent depressions. 
         [0018]    In particular, the engagement elements are in the form of approximately V-shaped hooks which lie in the pivoting plane and which have two limbs which are connected to one another at one side, wherein the engagement elements are in each case pivotably mounted at the free end of the second limb, and wherein, on the free end of the first limb, there is formed a contact head by way of which the engagement element enters into engagement, in the engagement position, with the running carriage. 
         [0019]    Another refinement of the conveyor installation according to the invention is characterized in that the engagement elements are attached to a chain which is driven and which is movable in sections along the running rail, and in that the swivel axis of each engagement element in each case coincides with a joint axis of the chain. 
         [0020]    In particular, the chain is in the form of an endless chain and is guided over at least two diverting wheels. Here, the chain may also be in the form of a roller chain. 
         [0021]    In particular, the chain, in the section in which it is moved along the running rail for the purposes of engagement, is guided in a guide rail such that the engagement elements arranged on the chain are situated and move outside the guide rail. 
         [0022]    In particular, a mechanism is provided by way of which engagement elements situated in the non-engagement position can be moved back into the engagement position. 
         [0023]    In particular, the mechanism comprises a static sliding guide which is tracked by the engagement elements that are moved past. 
         [0024]    In particular, means for tracking the sliding guide are arranged on the engagement elements. 
         [0025]    In particular, the tracking means comprise a tracking roller arranged rotatably on each engagement element. 
         [0026]    Alternatively, the tracking means may comprise a tracking cam formed on each engagement element. 
         [0027]    It is however also conceivable for the mechanism to comprise movable pressing means which, in order to pivot the engagement elements, are pressed against the engagement elements that are moved past. 
         [0028]    In particular, the pressing means comprise, on a synchronously running chain, pressing elements which are moved against the engagement elements. 
         [0029]    It is however also conceivable for the pressing means to comprise at least one static pressing unit with an active element which can be moved against the engagement elements that are moved past. 
         [0030]    Another refinement of the conveyor installation according to the invention is characterized in that the engagement elements are designed such that, in the second stable position, they can pass by the running carriage in the case of a relatively fast movement of the at least one running carriage. In this way, operating states are possible in which the running carriage, for example owing to drive action imparted by a continuous conveyor, moves faster than the engagement elements, that is to say can, in effect, “overtake” the engagement elements. 
         [0031]    In particular, in this case, the engagement elements are in the form of approximately V-shaped hooks which lie in a pivoting plane and which have two limbs which are connected to one another at one side, wherein the engagement elements are in each case pivotably mounted at the free end of the second limb, wherein, at the free end of the first limb, there is formed a contact head by way of which the engagement element enters into engagement, in the engagement position, with the running carriage, wherein the engagement elements are, at least in the region of the limbs, composed of an elastically deformable material, and wherein the limbs of the engagement elements are divided, in each case by a slot lying in the pivoting plane, into two similar limb parts which are spread apart when a relatively fast-moving running carriage passes by. 
         [0032]    Furthermore, it may be provided that, in the case of the engagement elements, in each case on the outer side in the region of the first limb, there is formed a run-in funnel which opens into the slot and which permits or facilitates the spreading-apart of the limb parts by an engagement element attached to the running carriage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    The invention will be explained in more detail below on the basis of exemplary embodiments in conjunction with the drawing. In the drawing: 
           [0034]      FIG. 1  shows, in a perspective illustration (in a view from below), a detail of a conveyor installation as per an exemplary embodiment of the invention; 
           [0035]      FIG. 2  shows a conveyor installation from  FIG. 1  with the drive unit for the chain equipped with the engagement elements in an accumulating operating mode; 
           [0036]      FIG. 3  shows, in various steps ( FIGS. 3( a ) to ( d ) ), the behaviour of the engagement elements of the conveyor installation from  FIG. 1  in the accumulating operating mode; 
           [0037]      FIG. 4  shows a conveyor installation as per another exemplary embodiment of the invention, in which the engagement elements are pivoted into the engagement position by virtue of tracking rollers running on a sliding guide; 
           [0038]      FIG. 5  shows a further exemplary embodiment similar to  FIG. 4 , in which the engagement elements are pivoted into the engagement position by virtue of tracking cams running on a sliding guide; 
           [0039]      FIG. 6  shows a further exemplary embodiment similar to  FIGS. 4 and 5 , in which the engagement elements are pivoted into the engagement position by way of jointly running pressing elements; 
           [0040]      FIG. 7  shows the pivoting of the engagement elements into the engagement position by way of a static pressing unit; 
           [0041]      FIG. 8  shows the section through the guide rail of the chain equipped with the engagement elements with the chain guided therein; 
           [0042]      FIGS. 9 and 10  show the problem that arises if a running carriage is, for example by way of a continuous conveyor (UF) engaging on one side, moved faster than an accumulating conveyor (SF) engaging on the other side; 
           [0043]      FIG. 11  shows side views, from different perspectives, of an engagement element or driver which allows the running carriage to move at a higher speed than an accumulating conveyor; 
           [0044]      FIG. 12  shows an accumulating conveyor (SF′), equipped with engagement elements as per  FIG. 11 , in interaction with a running carriage; and 
           [0045]      FIG. 13  shows the configuration from  FIG. 12  from a different perspective. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]      FIG. 1  shows, in a perspective illustration (in a view from below), a detail of a conveyor installation as per an exemplary embodiment of the invention. The conveyor installation  10  of  FIG. 1  comprises a running rail  11  which is guided through the space, which is fastened in suspended or some other fashion and of which, in  FIG. 1 , only a short section is depicted by way of example, and which may have curves and upwardly sloping and downwardly sloping sections. On the running rail  11 , individual running carriages, of which one running carriage  12  is depicted by way of example in  FIG. 1 , can move substantially freely along the running rail. 
         [0047]    The running rail  11  has, in cross-sectional profile, three outwardly open C-shaped or U-shaped profile sections  11   a ,  11   b  and  11   c , which are arranged mirror-symmetrically with respect to a vertical central plane. If the running carriage  12  engages, by way of its carriage body of U-shaped profile, around the running rail  11  from below, the profile sections  11   a  and  11   c  which are open towards the sides serve as support rails, in which the running carriage  12  runs by way of corresponding running rollers  15 , which are provided in pairs. The downwardly open profile section  11   b  performs guide tasks, and receives the guide rollers  16  of the running carriage  12 , which are likewise provided in pairs. 
         [0048]    At front and rear sides of the running carriage  12 , at multiple locations, there are arranged elastically deformable buffers  17  which cushion the abutment of multiple running carriages  12  running one behind the other on the running rail  11 . 
         [0049]    The running carriages  12  do not have a dedicated drive, but are either set in motion by the action of gravitational force on downward-sloping sections, or must be moved forward and upward or else braked by way of drive mechanisms which are arranged externally adjacent to the running rail  11  and which will be described in more detail below. For corresponding engagement from the outside, laterally protruding and oppositely situated engagement elements  18  are attached to the running carriage  12 , which engagement elements are in the form of bolts in the example illustrated. The running rail  11  and running carriage  12  in the illustrated form are the subject of separate patent applications. 
         [0050]    For the (activatable and re-releasable) drive of the individual running carriage  12 , there is provided, as per  FIG. 1 , an engagement device  13  which comprises a chain  22  equipped with pivotable engagement elements  23 , which chain, guided in a guide rail  19 , runs parallel to the running rail  11  at least in sections. The guidance of the chain  22  in the guide rail  19  is shown in detail, in a section, in  FIG. 8 . The chain  22  slides by way of one side in a guide groove  20  in the guide rail  19  and projects by way of the other side out through an opening slot  21 . The engagement elements  23  are arranged pivotably on said externally situated side of the chain  22 . Here, an (elongated) joint axis of the chain  22  serves in each case as swivel axis  24  for the engagement elements  23 . 
         [0051]    The engagement elements  23  are in the form of approximately V-shaped hooks which lie in the pivoting plane and which have two limbs S 1  and S 2  which are connected to one another at one side (see  FIG. 2 or 7 ). At the free end of the second limb S 2 , the engagement element  23  is mounted in each case pivotably on the chain  22 . At the free end of the first limb S 1  there is formed a contact head  23   c  by way of which the engagement element  23 , in the engagement position, enters into engagement with the associated engagement element  18  on the running carriage  12  (see e.g. the entire left-hand engagement element in  FIG. 2 ). 
         [0052]    The pivoting mechanism of the engagement elements  23  is designed such that the engagement elements  23  can in each case be pivoted back and forth between two stable positions. In one stable position (see for example the two right-hand engagement elements in  FIG. 7 ), the engagement elements  23  compulsorily enter into engagement, by way of the engagement element  18 , with a running carriage  12  when the latter is driven along by the engagement elements  23  during a forward movement of the chain  22 . In the other stable position (see for example the two left-hand engagement elements in  FIG. 7 ), the engagement elements  23  have been pivoted back out of the movement path of the engagement elements  18 , such that engagement is not possible (non-engagement position). It is self-evident that the dimensions (length) of the engagement elements  18 , and the arrangement (spacing) of the chain  22  relative to the running rail and the pivoting range of engagement elements  23  must be coordinated with one another such that this behaviour is possible. 
         [0053]    The two stable (end) positions of the engagement elements  23  as per  FIG. 7  are defined by a detent mechanism which, for each engagement element  23 , provides a detent element  25 , which is arranged in the interior region of the engagement element and which is in the form of a circular bolt, and two detent depressions  23   a  and  23   b , which are formed on the inner side of the limb S 1  ( FIG. 2 ). The bolt-like detent element  25  is, for the respective engagement element, arranged on the exact next chain joint that follows the swivel axis. One detent depression  23   a  is arranged on the free end of the limb S 1  directly in front of the contact head  23   c . The other detent depression  23   b  is situated immediately in front of the transition from the limb S 1  to the limb S 2 . When the engagement element  23  engages by way of the inner detent depression  23   b  on the detent element  25  (see the two right-hand engagement elements  23  in  FIG. 7 ), the engagement element is situated in the stable engagement position. By contrast, when the engagement element  23  engages by way of the outer detent depression  23  on the detent element  25  (see the two left-hand engagement elements  23  in  FIG. 7 ), the engagement element  23  is situated in the stable neutral position, in which engagement is not possible (non-engagement position). It is self-evident that, for functioning of the described detent mechanism, sufficient flexible elasticity of engagement element  23  in the pivoting plane is necessary. 
         [0054]    As emerges from the schematic illustration of  FIG. 2 , the chain  22  is part of a drive unit  26  which has two diverting wheels  27  and  28 , of which at least one is motor-driven (motor M) and over which the chain  22 , as an endless chain, is guided. The illustration shows the situation in the accumulating operating mode, in which an abutment  29  which can be pivoted into the running path of the running carriages  12   a ,  12   b  limits the free forward running of the running carriages. Firstly, the running carriages  12   a ,  12   b  are driven along by engagement elements  23 , which have been pivoted into the engagement position, by means of the chain  22  which is moving to the right, until a running carriage  12   b  strikes the abutment  29  and is stopped. This generates, by way of the engagement element  18  which is in engagement with the associated engagement element  23 , an opposing force which acts counter to the running direction and which pivots the engagement element  23  of the stopped running carriage  12   b  out of the stable engagement position into the stable non-engagement position, where the engagement element then locks with detent action. 
         [0055]    The individual phases of said process are depicted once again in sub-figures (a) to (d) of  FIG. 3 , where  FIG. 3( a )  illustrates the fully engaged situation, which leads, via multiple intermediate steps (b) and (c), to the fully pivoted-out situation in  FIG. 3( d ) . The same process occurs if further arriving running carriages, such as the running carriage  12   a  in  FIG. 2 , strike the already-stopped running carriage  12   b  and the associated engagement element  23  is likewise pivoted out of engagement owing to the opposing force that is generated. 
         [0056]    Since, in the case of an accumulating operating mode of said type, an ever greater number of engagement elements  23  are pivoted out of the engagement position and cannot pass into the engagement position again of their own accord, a mechanism is provided, as per  FIGS. 4-7 , which pivots the individual engagement elements  23  from the non-engagement position back into the engagement position in targeted and controlled fashion. 
         [0057]    A first such mechanism is depicted in  FIG. 4 . For this purpose in this refinement, the engagement elements  23 ′ are equipped in each case with a tracking roller  30  arranged rotatably on the tip of the “V”, by way of which tracking roller the engagement element  23 ′, during the movement of the chain  22 , tracks a sliding guide  31  arranged under said chain. Said sliding guide  31  has an upwardly sloping section which, by way of the tracking roller  30 , causes the engagement element  23 ′ that is moved by way of said tracking roller to be released from the stable non-engagement position and pivoted into the engagement position. 
         [0058]    Another refinement of a mechanism of said type is illustrated in  FIG. 5 . Here, the engagement elements  23 ″ are, at the tip of the “V”, equipped in each case with a tracking cam  32 , which in turn travels along a corresponding sliding guide  31 . 
         [0059]    It is however also conceivable, as per  FIGS. 6 and 7 , for active mechanisms to be provided for pivoting the engagement elements  23  back into the engagement position. In  FIG. 6 , by way of a further drive unit  33  with a chain  34  and diverting wheels  35 ,  36 , pressing elements  38  are, in a parallel section, moved synchronously along the chain  22  with the engagement elements  23 , wherein the pressing elements  38 , which in said section are supported in each case by way of a roller  41  on a support rail  37 , are, by way of their pressing body  39  which has an active element which is oriented toward the engagement elements  23  and which is in the form of a fixed plunger  40 , pressed by way of said plunger  40  against the limb S 2  of the associated engagement element, and thus presses or pivots said engagement element into the engagement position. It is self-evident that, instead of the plunger  40 , it is also possible for a roller or the like to be used as an active element. 
         [0060]    As per  FIG. 7 , it is however also possible for an individual, static pressing unit  42  to be provided which, by way of a deployable rod  43  with a pan-head-like plunger  44  (or a roller or the like) attached to the front end of the rod  43 , presses against the limb S 2  of an engagement element that is moving past. If a pressing unit  42  of said type is controlled in a manner coordinated with the movement of the chain  22 , it is possible for individual selected engagement elements  23  to be activated. If the plunger  44  remains deployed for a certain period of time, it is possible for multiple engagement elements  23  to be activated in succession. 
         [0061]    At this juncture, it is pointed out that the engagement elements  23  may not only set running carriages  12  in motion, as has primarily been discussed, but may also brake freely moving running carriages  12 . Thus, if for example the running carriage  12   a  shown in  FIG. 2  is moving faster than the chain  22  running adjacent thereto (e.g. owing to a downward slope), said running carriage is, by way of its engagement element  18 , released from the associated engagement element  23  at the far left in  FIG. 2 . Said free movement is then braked again, and reduced to the chain speed, when said running carriage has overtaken the next non-activated engagement element (second from the left) and abuts, by way of its engagement element  18 , against the outer side of the limb S 1  of the next engagement element (third from the left). 
         [0062]    All of the figures illustrate a chain  22  on which the engagement elements  23  are arranged with the maximum density. It is however self-evidently also conceivable for chain links without an engagement element to be interposed, if this is necessitated or made possible by the usage situation. Likewise, in the context of the invention, other types of detent mechanisms are conceivable for ensuring the two stable positions of the engagement elements. 
         [0063]    In the case of an accumulating conveyor of the type shown in  FIG. 1 , a problem may arise, which can be discussed on the basis of  FIGS. 9 and 10 : If the running carriage  12  is connected on one side to an accumulating conveyor SF and is driven on the other, opposite side by, for example, a continuous conveyor UF (not explicitly illustrated in  FIGS. 9 and 10 ), three separate speeds may arise, specifically the speed V SF  of the accumulating conveyor SF, the speed V LW  of the running carriage  12  and the speed V UF  of the continuous conveyor (not shown) ( FIG. 9 ). 
         [0064]    With the exemplary embodiments shown in the preceding figures, it is not possible for a running carriage  12  to move faster than the chain of the accumulating conveyor SF. If V UF =V LW &gt;V SF , the engagement element  23  which strikes the carriage  12  is pivoted from the engagement position into the non-engagement position. By contrast, if V UF =V LW &gt;V SF , the running carriage, by way of the engagement element  18 , strikes the next engagement element  23  (from behind), and a collision occurs. This greatly restricts the range of possible installation concepts for corresponding conveying installations. 
         [0065]    To obtain greater degrees of freedom in installation concepts, it would be desirable if, in a situation where V LW &gt;V SF , the accumulating conveyor SF allowed the running carriage, with its engagement element  18 , to pass by without great obstruction (indicated in  FIG. 10  by the arrow at the upper engagement element). 
         [0066]    This demand is satisfied if the engagement elements are designed such that, in the second stable position, they can allow the running carriage  12  to pass by in the case of a relatively fast movement of the at least one running carriage  12 . 
         [0067]    An engagement element of said type is shown from various perspectives in  FIG. 11 . The engagement element  45  from  FIG. 11  is similar, in terms of its external shape, to the engagement elements  23  shown in the preceding figures. Said engagement element is in the form of an approximately V-shaped hook which lies in a pivoting plane and which has two limbs S 1  and S 2  which are connected to one another at one side. The engagement element  45  has, integrally formed on the free end of the second limb S 2 , a hub  46  with an axial bore  47  which serves for the pivotable mounting. On the free end of the first limb S 1  there is formed a contact head  45   c  by way of which the engagement element  45 , in the engagement position, enters into engagement with the running carriage  12 . The special feature now consists in the fact that the engagement element  45  is, at least in the region of the limbs S 1  and S 2 , composed of an elastically deformable material, e.g. polyoxymethylene (POM), and that the limbs S 1  and S 2  are, as far as the hub  46 , divided by a slot  48 , which lies in the pivoting plane, into two similar limb parts S 1   a, b  ( FIG. 11 ) and S 2   a, b  ( FIG. 13 ) which, when a relatively fast-moving running carriage  12  passes by, are spread apart by the engagement element  18  of said running carriage such that the running carriage  12  can pass by. 
         [0068]    In order that this is particularly easily possible without the spreading also occurring in the opposite direction, it is provided that, in the case of the engagement element  45 , a run-in funnel  49  which opens into the slot  48  is formed on the outer side in the region of the first limb S 1 . To initiate the spreading process, the engagement element  18  on the running carriage enters into said run-in funnel  49  and, owing to the oblique funnel walls, spreads in particular the limb parts S 1   a  and S 1   b  elastically apart from one another, to such an extent that said engagement element can pass by. 
         [0069]      FIGS. 12 and 13  show, from different viewing directions, the configuration of a conveyor installation having an accumulating conveyor SF′ equipped with the slotted engagement elements  45  and having an associated (unchanged) running carriage  12 .