Patent Publication Number: US-9410295-B2

Title: Rail system, in particular for an in-floor electric conveyer system

Description:
RELATED APPLICATIONS 
     This application is a national phase of International Application No. PCT/EP2012/001025 filed on Mar. 8, 2012, which claims the filing benefit of German Patent Application No. 10 2011 016 349.2 filed on Apr. 7, 2011, the contents of both of which are herein incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a rail system, in particular for an in-floor electric conveyor system, having 
     a) a main track, which comprises at least two fixed parallel rails; 
     b) at least two secondary tracks which enclose an angle and each have as many fixed rails as the main track; 
     c) a switch which is arranged between the main track and the secondary tracks and comprises:
         ca) a movable rail section for each rail of the main track, which is capable of forming at least part of the connection between the rail of the main track and a rail of the secondary track in one position;   cb) at least one actuating mechanism for moving the movable rail sections.       

     Whereas the earlier prior art saw the frequent use of switches which made it necessary for the vehicle travelling over the switch to stop on the switch during the changeover, more recent times have seen an increase in the use of continuously operating switches, where the vehicle can travel over the switch without stopping. The advantages of such continuously operating switches are obvious: the throughput of vehicles through the rail system is greater since no time is required for braking, stopping and re-accelerating the vehicle in the region of the switches. 
     A continuously operating switch of the type mentioned at the outset is described in DE 20 2008 010 439 U1. Here, each rail of the main track is associated with as many movable rail sections as there are secondary tracks. These movable rail sections are displaced linearly in order to close the gaps between the corresponding rails after the desired connection between the main track and a secondary track. However, this involves a relatively high structural expenditure and spatial requirement. Only relatively long response times of the switch are possible due to the sluggishness of the system. This reduces the throughput through the rail system. 
     A further continuously operating switch is disclosed in DE 20 2008 016 678 U1. This likewise calls for as many movable rail sections for each rail of the main track as there are secondary tracks. These movable rail sections are arranged on a turntable here and are all rotated together about a centre of rotation. However, the overall height of a construction of this type is considerable and, in many cases, requires an inherently undesirable pit. Moreover, the structural expenditure is to all intents and purposes comparable to that required for the rail system of DE 20 2008 010439 U1. 
     An object of the present invention is to construct a rail system of the type mentioned at the outset so as to reduce the structural expenditure, whilst taking particular care that the lateral guide faces of the rails also have no abrupt changes of direction in the region of the switch. 
     SUMMARY OF THE INVENTION 
     This object may be achieved according to the invention in that 
     d) each rail of the main track has a single movable rail section associated therewith, which is permanently physically connected to the corresponding rail of the main track via a joint and can be optionally connected to a fixed rail of each secondary track through a pivotal movement about this joint; 
     wherein 
     e) each joint comprises
         ea) at least one end face of the rail of the main track, which is constructed as part of a rotational face about the axis of a pivot pin;   eb) at least one end face of the movable rail section, which abuts against the end face of the fixed rail and is shaped in a complementary manner thereto;   ec) at least one transition body which overlaps the fixed rail and the movable rail section and is connected in one end region to the fixed rail and in the other end region to the movable rail section in articulated manner, wherein at least one end face of the transition body realises a contour-adapted transition between the fixed rail and the movable rail section in at least one position of the movable rail section.       

     According to the invention, and contrary to the prior art, it is no longer the case that, for each path producing a connection between a rail of the main track and the associated rails of the different secondary tracks, a distinct movable rail section is provided which is moved into the corresponding position upon adjustment of the switch. Instead, according to the invention, only a single movable rail section, which can be optionally connected to a rail of each secondary track through a pivotal movement about a joint, is used for each rail of the main track. This means that the number of movable rail sections required is considerably lower, which not only considerably reduces the costs but also the dimensions of a rail system of this type. The above-mentioned secondary condition, that the guide face of the different rails should have no abrupt changes of direction, is ensured by the special construction of the joints which connect the rails of the main track respectively to the associated movable rail sections. The transition body provided in these joints ensures that the transition between the lateral guide faces of the rails of the main track and the lateral guide faces of the movable rail section is made smoother in at least one position of the movable rail section. 
     Expediently, the rotational faces on the end regions of the fixed rails and the movable rail sections are the lateral faces of a circular cylinder or a right circular cone. 
     It is the norm with switches that at least some of the connecting paths between rails of the main track and rails of the secondary tracks cross. Gaps have to be provided at the crossing points in these connecting paths, which can be closed by a further movable rail section to produce the desired connection. In the prior art, this often occurs through a linear displacement of a plurality of movable rail sections or by rotating a single movable rail section about an axis located in its centre. 
     According to the invention, it is preferred if the gap-closing further movable rail section is rigidly connected to one of the movable rail sections, which is connected to a rail of the main track via a joint. In this case, the synchronism of the movements of the different movable rail sections is ensured without complex control means. It is optionally possible to dispense with a separate actuating mechanism for moving this further movable rail section. 
     It is generally favourable if all movable rail sections can be moved by way of a single actuating mechanism. Again, the reason for this is the reduction in structural and control-related expenditure. 
     The present invention is particularly suitable for such rail systems as those in which lines for supplying power to the vehicles traveling on the rail system and/or for transmitting signals from and/or to the vehicle are provided along at least one of the rails of the main track, along the movable rail section associated with this main track and along at least one rail of each secondary track. It is particularly favourable here that there is a continuous physical connection between the rails of the main track and the movable rail sections associated with this main track and there is no occurrence of relatively large gaps or breaks, as was the case in the prior art. 
     It is to be understood that the aspects and objects of the present invention described above may be combinable and that other advantages and aspects of the present invention will become apparent upon reading the following description of the drawings and detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention is explained in more detail below with reference to the drawing, which shows: 
         FIG. 1  the plan view of a rail system with a switch in a first switch position; 
         FIG. 2  the plan view of the rail system of  FIG. 1  in the other switch position; 
         FIG. 3  a section through the rail system of  FIGS. 1 and 2  according to line III-III of  FIG. 1 ; 
         FIG. 4  a section through the rail system of  FIGS. 1 and 2  according to line IV-IV of  FIG. 1 ; 
         FIG. 5  the plan view on an enlarged scale of a joint which is used in the switch of the rail system, in a first position; 
         FIG. 6  a plan view of the joint in a second position; 
         FIG. 7  the plan view of the joint of  FIGS. 5 and 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. 
     Reference is firstly made to  FIGS. 1 and 2 , in which a rail system is shown which is denoted as a whole by the reference numeral  1  and comprises a main track  2  and two secondary tracks  3 ,  4  in the section shown. Each track  2 ,  3 ,  4  comprises two parallel rails  5 ,  6  and  7 ,  8  and  9 ,  10 . The tracks  2 ,  3  and  4  and therefore also the rails  5 ,  6 ,  7 ,  8 ,  9 ,  10  are fixed. Whilst the secondary track  3  is located in the linear continuation of the main track  2 , the secondary track  4  branches off at a particular angle from the other secondary track  3 . 
     The main track  2  can optionally be connected to the secondary track  3  or the secondary track  4  with the aid of a switch, which is denoted as a whole by the reference numeral  11 . The switch  11  comprises a pivotable rail section  12  with which the rail  5  is associated, and a pivotable rail section  14  with which the rail  6  is associated. The rail section  12  here is connected to the rail  5  via a first joint  13  and the rail section  14  is connected to the rail  6  via a second joint  15 . The precise construction of these joints  13 ,  15  is described further below. 
     The length of the pivotable rail section  12  is such that, in a first switch position, which is shown in  FIG. 1 , it can connect the rail  5  to the rail  9  of the second secondary track  4 . In corresponding manner, the length of the pivotable rail section  14  is such that it can connect the rail  6  of the main track  2  to a fixed intermediate rail section  16 , as shown in  FIG. 1 . 
     In the second position of the switch  11 , which is shown in  FIG. 2 , the rail  5  of the main track  2  is connected to the track  7  of the first secondary track  3  by way of the pivotable rail section  12 ; the rail  6  of the main track  2  is connected to a fixed intermediate rail section  17  by way of the pivotable rail section  14 . 
     The pivotal movement of the two rail sections  12  and  14  between the two positions shown in  FIGS. 1 and 2  is effected with the aid of an actuating mechanism, which is only shown schematically in  FIGS. 1 and 2  and is provided as a whole with the reference numeral  18 . 
     The pivotable rail section  12  is rigidly connected to a further pivotable rail section  21  by way of two cross-pieces  19 ,  20 . This means that the pivotable rail section  21  is always pivoted together with the pivotable rail section  12  by the actuating device  18 . 
     The pivotable rail section  21  is dimensioned such that, in the first position of the switch  11  as shown in  FIG. 1 , it can close the gap between the fixed intermediate rail section  16  and the rail  10  of the second secondary track  14 . In the other position of the switch  11 , which is shown in  FIG. 2 , this pivotable rail section  21  fills the gap between the fixed intermediate rail section  17  and the rail  8  of the first secondary track  3 . 
     The inherently rigid arrangement of the pivotable rail section  12  and the pivotable rail section  21  is supported and guided in that end region which is remote from the joints  13 ,  15  by a stabiliser wheel  22  which, in turn, can run in a connecting guideway  23  which curves in a circular arc shape. The stabiliser wheel  22  is in turn mounted in a strut  24  which connects the two cross-pieces  19 ,  20  to one another. 
     In the exemplary embodiment described here, all movable parts are therefore activated together by a single actuating drive, namely the actuating mechanism  18 . In terms of the control technology, this is particularly simple since the synchronism of the movement of all movable parts is ensured in this way. However, it is essentially also possible to provide a plurality of actuating mechanisms for different movable parts as seems expedient. 
     The rails  5  to  10  of the rail system  1  described here are I-shaped profiles, as shown in  FIGS. 3 and 4 . In the region of the main rail  2  and the two secondary rails  3 ,  4 , these profiles are connected to one another at regular spacings by cross-pieces  25  which are in turn supported on the floor of the room by columns  26 ,  27 . Unilateral supports  28 , one of which is shown in  FIG. 4 , are used where it is not readily possible to connect opposing, mutually parallel-extending rails in this manner. Specific explanation of this  FIG. 4  should not be necessary. 
     To describe the joint  13  which connects the rail  5  of the main rail  2  to the pivotable rail section  12 , reference is now made to  FIGS. 5 to 7 . The second joint  15 , which connects the rail  6  of the main track  2  to the pivotable rail section  14 , is constructed in the same way and therefore does not need to be described specifically. 
     The end regions of the rail  5  of the main track  2  and the pivotable rail section  12  of the switch  11  are shown again in  FIGS. 5 to 7 . On account of their I-profile, as shown in  FIGS. 3 and 4 , they both have an upper rail flange  29  and  52  and a lower rail flange  30  and  53 . The upper and lower faces of the rail flanges  29 ,  30  and  52 ,  63  extend parallel to one another, generally horizontally. The upper faces of the upper rail flanges  29 ,  52  serve as running faces for drive and carrying rollers of an in-floor electric conveyor system (not shown) with a variable track width, which is known per se. The narrow vertical faces of the rail flanges  29 ,  30 ,  52 ,  53  form upper guide faces  31   a ,  31   b ,  52   a ,  52   b  and lower guide faces  32   a ,  32   b ,  53   a ,  53   b  for guide rollers of the vehicle. 
     The upper rail flanges  29 ,  52  and the lower rail flanges  30 ,  53  are in each case connected to one another in one piece by way of a web  33 ,  54 . The web  33  of the rail  5  and the web  54  of the rail section  12  end, as shown in  FIG. 7 , at a spacing from a pivot pin  34  forming the axis of the joint  13 . The manner of mounting the pivot pin  34  on the rail  5  and the rail section  12  will be clarified further below. 
     The rail flanges  29 ,  30  of the rail section  5  have a slot  35  and  36  in that end region which faces the pivotable rail section  12 . The slots  35 ,  36  extend parallel to the upper and lower running faces of the rail flange  29 ,  30 , i.e. perpendicularly to the lateral guide faces  31   a ,  31   b . They extend over the entire width of the rail flanges  29 ,  30  and are open towards the lateral guide faces  31   a ,  31   b  and the end face  37  of the rail  5 . The rail flanges  29  and  30  are therefore fork-shaped in the region of the end face  37  as seen from the side as in  FIG. 7 . 
     Those end faces of the flange regions  29   a ,  30   a  located above the slots  35 ,  36  which are facing the pivot pin  34  are provided with the reference numerals  38 ,  39 , the end faces of the flange regions  29   b ,  30   b  located below the slots  35 ,  36  are provided with the reference numerals  40 ,  41 . 
     Beyond the end faces  40 ,  41  of the lower flange regions  29   a ,  30   b , the ends of the pivot pin  34  are guided through the respective upper flange regions  29   a ,  30   a  and mounted therein. 
     The end faces  38 ,  39  of the upper flange regions  29   a ,  30   a  are constructed as parts of a lateral face of a circular cylinder which is coaxial to the pivot pin  34  and are convex here as seen in the direction of the end faces  38 ,  39 . The end faces  40 ,  41  of the lower flange regions  29   b ,  30   b  are likewise constructed as part of a lateral face of a second circular cylinder which is coaxial to the pivot pin  34  but are concave as seen in the direction of the end faces  40 ,  41 . 
     The pivotable rail section  12  is constructed analogously to the fixed rail section  5 . In particular, in their end region facing the fixed rail  5 , the rail flanges  52 ,  53  are constructed in a complementary manner to the end region of the fixed rail  5 . The pivot pin  34  is mounted in each case in the lower flange region  55   b  and  56   b  of the pivotable rail section  12 . 
     The slots  35 ,  36  of the fixed rail  5  correspond to slots  42 ,  43  of the pivotable rail section  12 , which in each case separate an upper flange region  55   a ,  56   a  from the lower flange region  55   b ,  56   b.    
     The end faces  44 ,  45  of the upper flange regions  55   a ,  56   a  of the pivotable rail section  12  lie flat against the end faces  38 ,  39  of the fixed rail  5  in each pivotal position. Accordingly, the end faces  46 ,  47  of the lower flange regions  55   b ,  56   b  of the pivotable rail section  12  lie flat against the end faces  40 ,  41  of the fixed rail  5  in all pivotal positions. 
     When the pivotable rail section  12  is pivoted with respect to the fixed rail section  5 , the mutually facing end faces slide along one another so that the upper and lower running and guide faces of the rail  5  and the rail section  12  merge into one another in practically seamless manner in all pivotal positions. 
     A respective elongated transition body in the form of an approximately box-shaped transition plate  48  and  49  is located in the slots  35 ,  36  of the fixed rail  5  and the slots  42 ,  43  of the pivotable rail section  12 . The width of the transition plates  48 ,  49  perpendicularly to the direction of travel corresponds to the corresponding extent of the rail flanges  29 ,  30 ,  52 ,  53 . With a linear arrangement of the rail sections  5 ,  12 , as shown in  FIGS. 2 and 6 , the narrow longitudinal sides of the transition plates  48 ,  49  are flush with the lateral running faces  31   a ,  31   b ,  32   a ,  32   b ,  52   a ,  52   b ,  53   a ,  53   b  of the upper rail flanges  29 ,  52  and the lower rail flanges  30 ,  53 . 
     The length of the transition plates  48 ,  49  in the direction of travel is less than the extent of the slots  35 ,  36 ,  42 ,  43  in this direction. Therefore, the transition plates  48 ,  49  do not abut against the end walls of the slots  35 ,  36 ,  42 ,  43  when the rail section  12  is pivoted. 
     The transition plates  48 ,  49  each have an elongated hole (not shown in the drawing) in the vicinity of their narrow end faces for a respective pintle  50 . The pintles  50  are rotatable and displaceable in the elongated holes. The elongated holes extend parallel to the longitudinal sides of the transition plates  48 ,  49 . 
     The axes of the pintles  50  extend parallel to the axis of the pivot pin  34 . The pintles  50  are fastened in the corresponding lower flange regions  29   b ,  56   b  and upper flange regions  30   a ,  56   a.    
     Approximately centrally, the transition plates  48 ,  49  each have a continuous pivot pin opening (likewise not shown in the drawing) through which the pivot pin  34  is guided. The pivot axis openings are dimensioned so that the pivot pin  34  does not abut against the edges of the pivot axis openings in any pivotal position of the pivotable rail section  12 . 
     Upon a pivotal movement of the pivotable rail section  12 , the transition plates  48 ,  49  are automatically pushed in the direction of the lateral guide face on the inner curve side as a result of the cooperation between the pintle  50  and the elongated holes. They thereby produce an alignment of the contours and smooth the transition between the lateral guide faces  31   a ,  31   b ,  32   a ,  32   b  of the fixed rails  5  on the inner curve side and the lateral guide faces  52   a ,  52   b ,  53   a ,  53   b  of the pivotable rail section  12 . 
       FIGS. 5 and 6  show a peculiarity in the shape of the end regions of the rail  5  and the rail section  12 . The upper lateral guide faces  31 ,  52   a  in  FIG. 5  do not extend linearly as seen in plan view, but are both curved so that, in the pivotal position of the switch  11  shown in  FIG. 5 , they form a smooth, jolt-free and uniformly curved guide face for the guide rollers of the vehicle. 
     In the extended position of the switch  11  shown in  FIG. 6 , the lateral guide faces  31   a ,  32   a  of the rail  5  and the lateral guide face  52   a ,  53   a  of the rail section  12  in these end regions would themselves result in a discontinuity. However, the transition plates  48 ,  49  project laterally in this position so that, on the outside of the rail flange  29 ,  30 ,  52 ,  53 , they ensure a smooth transition between the lateral guide faces  31   a ,  32   a  of the fixed rail  5  and the lateral guide faces  52   a ,  53   a  of the pivotable rail section  12 . 
     Contact lines  51  extend along the rail  5  of the main track  2 , over the pivotable rail section  12  and along the rail  7  of the first secondary track  3  and the rail  9  of the second secondary track  4 , as shown in  FIGS. 3 and 4 . These contact lines serve to supply energy and/or transmit signals between the vehicles (not shown) of the in-floor electric conveyor system and a corresponding control and/or energy supply unit. 
     In the region of the transition between the fixed rail  5  and the pivotable rail section  12 , these contact lines  50  have flexible connecting lines, for example in the form of copper braiding. These connecting lines are adapted to all possible pivotal movements and thus also enable continuous contact through the sliding contacts of the vehicle in the region of the transition. 
     As an alternative to a mechanical sliding connection between the sliding contacts of the vehicle and those on the rails, a contactless energy and/or signal transmission between cables, which are laid along the rails, and corresponding receivers of the vehicle are also possible. 
     It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.