Patent Publication Number: US-6668737-B1

Title: Transport system comprising a vehicle with good cornering performance which can be moved on rails

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a transport system with a vehicle, which can be moved on rails arranged next to each other. 
     A supportive running gear for a trolley conveyor to allow travel on a support utility for below-ground drifting is known from German patent DE 32 38 402. The trolley conveyor exhibits two parallel rails at a certain distance from each other, on which a vehicle for the support utility can be moved. The vehicle essentially consists of two crabs which are arranged behind each other when seen in the direction of travel, and are connected with each other by means of a steering rod. A cantilever, which can be pivoted about a horizontal axis, is latched onto the first crab. A pulling device, connected to lifting gear secured to the second crab, grips the cantilever&#39;s empty end. Each of the two crabs exhibits four running gears, each of which is mounted about horizontal axes at the ends of one of the crab&#39;s cross members and can be pivoted in the direction of travel. The cross member on the other hand is connected with that part of the crab on which the arm is mounted, about a horizontal axis in the direction of travel. 
     Furthermore, each running gear is connected with the cross member around a vertical axis and can be rotated. In addition, as it pertains to the running gears on one vehicle side, another essentially horizontal axis transverse in direction of travel, located between the running gear and the cross member, provides for the crabs&#39; linear displacement at right angles to the direction of travel. Due to the multitude of pivoting possibilities provided for each crab and each running gear, the vehicle at hand may also be guided on rails run irregularly. Due to the possibility of displacing the crabs&#39; running gears transversely, even larger modifications in the rails&#39; tracks can be offset. 
     Further, German patent document DE 195 09 727 C1 describes a transport system with a vehicle able to travel on rails and with good cornering performance. This transport system is not designed as a trolley conveyor, rather the vehicle travels on rails mounted on the ground and exhibits four running gears at its corner points, which are mounted around vertical axes and able to pivot. The running gears on one vehicle side are not arranged directly on the frame but via bearing shanks, whose ends are turned away from the running gears, mounted on the frame around a vertical pivot axis and are able to pivot. Due to this guiding arrangement, it is possible that, on one hand, tolerances of the rails running parallel and next to each other can be offset by the vehicle and, on the other hand, it is also possible to travel around narrow 90° curves. When seen in the direction of travel, the pivot axes of the bearing shanks are therefore arranged in the area of half the vehicle&#39;s length as well as behind each other, when seen in the direction of travel. 
     In order to enable travel around narrow 90° curves, the rails are specially designed for the curve area. Starting with rails running as parallel as possible, the inner rail is retracted in the direction of the outer rail in such a manner that the inner, rear running gear maintains its direction of travel while traveling through the curve area. This is done to cause the speed of the inner rear running gear to approach zero while traveling through the curve area, however not reversing its direction of travel. Therefore even narrow curve radii can be traveled smoothly as well as without bumps. 
     Furthermore, DE 39 00 516 A1 describes a transport system with a vehicle guided by rails and a turnout. The vehicle essentially consists of a right-angle frame, whose corner areas have running gears, which can be pivoted about vertical axes. The running gears can be moved on rails located next to and at a distance from each other. The rails of different rail paths cross each other, preferably at a right angle. The crossing areas are provided with turnouts, in order to enable the vehicles to change rail paths. The turnouts essentially consist of rail sections arranged in the rails&#39; crossing points and can be pivoted about a vertical axis. Transferring a vehicle from the first to the second rail path takes place after the vehicle enters the turnout by moving the rail sections, which can be pivoted. Therefore the vehicle&#39;s running gears are also pivoted by 90°, and subsequently the vehicle can move in the direction of the second rail thread. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a transport system is provided that includes a plurality of rails and a vehicle that travels on the rails. The vehicle includes a frame with a plurality of cross members and guide members. The frame further includes a plurality of running gears mounted thereon which are pivotable about a vertical axis. A pair of stop elements are included that can be pivoted approximately 90° about a vertical pivot axis between a cross position and a longitudinal position. At least one slide element is also mounted on the cross members that guides the running gears on the guide members in a linearly-movable manner at right angles to the longitudinal direction of travel of the vehicle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a transport system with a vehicle according to one aspect of the invention; 
     FIG. 2 is a side view of one of the vehicles of FIG. 1; 
     FIG. 3 is plan view of the vehicle of FIG. 2; 
     FIG. 4 is an enlarged section of the running gear area during the vehicle&#39;s transverse travel; 
     FIG. 5 is an enlarged section of the running gear area during the vehicle&#39;s longitudinal travel; and 
     FIG. 6 is a front view of the vehicle of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is based on the task of creating a transport system of the type described in the Background section, which exhibits optimized applications possibilities. 
     In accordance with the invention, the possibility of the running gears&#39; linear displacement on one side of the transport system&#39;s vehicle in a transverse direction to the vehicle&#39;s longitudinal direction of travel provides that, on one hand, curves running in the vehicle&#39;s longitudinal direction of travel can be traveled and, on the other hand, turnouts known from the current state of technology and arranged in corner/cross areas can also be traveled by means of turnout rail sections, which can be pivoted about a vertical direction. Therefore the vehicles&#39; applications have been expanded. 
     Advantageous design development is achieved by locking the running gears as the vehicles travel in a transverse direction, so that the movable running gears cannot move at all during transverse travel, and therefore their track is maintained in order to enable further pivoting of the running gears by 90°, when arriving at the next turnout in a corner/crossing area. 
     An especially simple advantageous design development of the running gears&#39; retention exists with protrusions protruding to the outside from the running gears&#39; outer circumference. These protrusions abut to adjustable stop elements with the running gears pivoted in the transverse direction of travel. These stop elements are mounted on the vehicle&#39;s cross members. Due to the linear guidance of the running gears to allow their transverse displacement, a more direct introduction of forces into the vehicle&#39;s frame is possible, compared with the use of guide bars. Quiet travel without bumps is ensured, as forces are introduced into the vehicle&#39;s frame at the vehicle&#39;s corner points. 
     Construction space as well as construction height are conserved. Furthermore, as the possibility for linear displacement already disallows displacing the running gear in the longitudinal direction of travel, power locking can be dispensed with when locking for transverse travel. In especially simple cases, only the previously described protrusions and stops are required. The running gears may also be completely and easily dismounted from the transversely running guide elements as well as remounted for maintenance work. Further, the use of guide rails and slide elements for the running gears&#39; transverse movement is especially advantageous in that a low push resistance also results in low steering forces. 
     This vehicle is especially suitable for use on rails whose cross sections are designed in I-shape and braced with ground supports. This transportation system is therefore suitable for traveling around stock areas, whose outline is designed mostly at a right angle, in order to pick up or drop off piece goods from individual stock areas. The invention is also suitable for vehicles and rails in the trolley conveyor area. 
     Illustration  1  depicts a top view onto a transport system with vehicle  1  with good cornering performance on a section with two parallel rails  4 , which are at a distance from each other and aligned largely parallel to each other at least on their straight paths. The run of rails  2  indicates that, on one hand, corner/crossing areas  3  and, on the other hand, curve areas  4  can be traveled by vehicles  1 . The actual vehicle  1  is not obvious in illustration  1 , as skid  5  lies on each vehicle. Skid  5  transports vehicle  6 . Vehicles  1  are able to change from longitudinal direction of travel L into transverse direction of travel Q in corner/crossing area  3 . Therefore two short turnout rail pieces  7  are provided in the rails&#39; crossing points directed in longitudinal direction of travel L as well as transverse direction of travel Q. Turnout rail pieces  7  can pivot about a vertical axis by at least 90° from the longitudinal direction of travel L to the transverse direction of travel Q as well as vice versa, as required. These turnout rail pieces may be designed according to those disclosed in DE 39 00 615 A1 referenced herein in the Background section, and incorporated herein by reference at the beginning. The pivoting of turnout rail pieces  7  occurs immediately after vehicle  1  with running gears  8  (see FIG. 2) which may also pivot about vertical axes  9 , comes to a halt on turnout rail pieces  7  and as soon as axes  9  of running gears  8  as well as the pivot axes of turnout rail pieces  7 , align with each other. It is therefore possible that vehicle  1  arriving in longitudinal direction of travel L may leave corner/crossing area  3  in the transverse direction of travel Q by means of jointly pivoting the turnout rail pieces  7  and the running gears  8  by 90° each. 
     FIG. 2 depicts a side view of vehicle  1  on a straight section of rail  2 . FIGS. 3 and 6 show a top and front view of FIG. 2, respectively. FIGS. 2,  3  and  6  describe the design of vehicle  1  in more detail. FIG. 3 shows that the vehicle features rectangular frame  10  with four parallel side members  10   a  running at a distance as well as in a longitudinal direction of travel L. Seen in the longitudinal direction of travel L, side member  10   a &#39;s front and rear ends are connected with each other via two cross members  10  each. Only the two inner side members  10   a  run the entire length of vehicle  1 . 
     The two outer side members  10   a  are broken through in the area between cross members  10   b , which are arranged at a distance from each other. It is apparent that the acquired construction space is used to store running gears  8 , which are arranged in the corner points of frame  10 . Running gears  8  essentially consist of one wheel or castor  12  (see FIG.  4 ), which runs on the surface of rail  2 . Rail  2  is therefore supported via support  13  on the ground  14  in a factory, plant, or other type of facility. Each castor  12  is mounted about vertical axis  9  and pivots. FIG. 2 shows that the bearing of the running gears is done via connection plate  15 , which is arranged on cross members  10   b.    
     FIG. 3 further shows that running gears  8  of vehicle  1 &#39;s left side, when seen in the longitudinal direction of travel L, are additionally mounted transversely to the longitudinal direction of travel L and can be displaced. It is therefore also possible to move vehicle  1  through curves wherein the axial distance of running gears  8  facing each other may change in the curves, depending on the design of the run of rails  2 . In order to allow the left running gears  8 &#39;s linear possibility of transverse displacement, connection plate  5  is mounted on the top sides of cross members  10   b  via guide elements  11 . Guide elements  11  permit displacement of running gears  8  only in a direction transverse to the longitudinal direction of travel L. 
     FIGS. 2,  3 , and  6  furthermore show that bearing rollers  19  are provided on cross members  10   a . Skid  5  with motor vehicle  6  sits on these bearing rollers. Skid  5  is therefore kept on bearing rollers  19 , and hence on vehicle  1 , via locking, which is not depicted. The illustrations also show that the running gear is powered by drive motor  20 , which is flanged to running gear  8 . In this context, FIG. 6 shows that conductor lines  21  run along the I-shaped rails. Drive motor  20  is provided with power via these conductor lines. 
     FIGS. 4 and 5 each further show an enlarged section of a running gear area from FIG. 3, when vehicle  1  is traveling in a transverse and longitudinal direction, respectively. FIGS. 4 and 5 also depict the detailed construction of guide element  110 . 
     Guide element  11  essentially consists of guide rail  11   a , which is screwed onto the top side of cross member  10   b , as well as slide elements  11   b , which embrace the guide rail, and can be displaced alongside of it. They are connected with connection plate  15  on the side opposite guide rail  11   a.    
     FIG. 5 further shows that stops or protrusions  16  are provided alongside running gear  8 . These protrusions protrude from running gear  8 &#39;s circumferential outline. Stops  16  have no function during vehicle  1 &#39;s longitudinal direction of travel and are therefore in an idle position. FIG. 4, on the contrary, shows protrusions  16 &#39;s position when in operation. FIG. 4 depicts running gear  8  during vehicle  1 &#39;s transverse direction of travel. Therefore, running gear  8  is pivoted by 90° about its axis  9 , and protrusions  16  abut against adjustable stop elements  17 , which are connected with cross members  10   b . This warrants that the possibility of transverse displacement of the running gears  8  on the left side of vehicle  1 , which is desired for vehicle  1 &#39;s travel in the longitudinal direction of travel L, is canceled during transverse travel. With this arrangement working together with running gear  8 , which is traveling on rail  2  and is additionally guided along the outer sides of rail  2  by guide rollers  18 , which are mounted on the running gear about vertical axes and can be pivoted, running gear  8  is maintained in a defined position even when traveling in the transverse direction Q. This is necessary, as the wheel tracks of wheels  12  may not change during entry into a subsequent corner/crossing area with turnout rail pieces  7 , which can pivot. 
     Symbol reference list 
       1  Vehicle 
       2  Rail 
       3  Corner/crossing area 
       4  Curve area 
       5  Skid 
       6  Motor vehicle 
       7  Turnable turnout rails 
       8  Running gears 
       9  Axes 
       10  Frame 
       10   a  Side member 
       10   b  Cross member 
       11  Guide element 
       11   a  Guide rail 
       11   11   b  Slide element 
       12  Wheel 
       13  Support 
       14  Ground 
       15  Connection plate 
       16  Protrusion 
       17  Stop element 
       18  Guide rollers 
       19  Bearing rollers 
       20  Drive motor 
       21  Conductor lines 
     L Longitudinal direction of travel 
     Q Transverse direction of travel 
     Transport system with a vehicle, which can be moved on rails and exhibits good cornering performance characteristics 
     Description 
     The invention relates to a transport system with a vehicle, which can be moved on rails arranged next to each other and has good cornering performance according to the generic term in claim  1 . 
     A supportive running gear for a trolley conveyor to allow travel on a support utility for below-ground drifting is known from German patent DE 32 38 402. The trolley conveyor exhibits two parallel rails at a certain distance from each other, on which a vehicle for the support utility can be moved. The vehicle essentially consists of two crabs which are arranged behind each other when seen in the direction of travel, and are connected with each other by means of a steering rod. A cantilever, which can be pivoted about a horizontal axis, is latched onto the first crab. A pulling device, connected to lifting gear secured to the second crab, grips the cantilever&#39;s empty end. Each of the two crabs exhibits four running gears, each of which is mounted about horizontal axes at the ends of one of the crab&#39;s cross members and can be pivoted in the direction of travel. The cross member on the other hand is connected with that part of the crab on which the arm is mounted, about a horizontal axis in direction of travel. 
     Furthermore, each running gear is connected with the cross member around a vertical axis and can be rotated. In addition, as it pertains to the running gears on one vehicle side, another essentially horizontal axis transverse in direction of travel, located between the running gear and the cross member, provides for the crabs&#39; linear displacement at right angles to the direction of travel. Due to the multitude of pivoting possibilities provided for each crab, respectively each running gear, the vehicle at hand may also be guided on rails run irregularly. Due to the possibility of displacing the crabs&#39; running gears transversely, even larger modifications in the rails&#39; tracks can be offset. 
     Further, German patent document DE 195 09 727 C1 describes a transport system with a vehicle able to travel on rails and with good cornering performance. This transport system is not designed as a trolley conveyor, rather the vehicle travels on rails mounted on the ground and exhibits four running gears at its corner points, which are mounted around vertical axes and able to pivot. The running gears on one vehicle side are not arranged directly on the frame but via bearing shanks, whose ends are turned away from the running gears, mounted on the frame around a vertical pivot axis and are able to pivot. Due to this guiding arrangement, it is possible that, on one hand, tolerances of the rails running parallel and next to each other can be offset by the vehicle and, on the other hand, it is also possible to travel around narrow 90° curves. When seen in the direction of travel, the pivot axes of the bearing shanks are therefore arranged in the area of half the vehicle&#39;s length as well as behind each other, when seen in the direction of travel. 
     In order to enable travel around narrow 90° curves, the rails are specially designed for the curve area. Starting with rails running as parallel as possible, the inner rail is retracted in the direction of the outer rail in such a manner that the inner, rear running gear maintains its direction of travel while traveling through the curve area. This is done to cause the speed of the inner rear running gear to approach zero while traveling through the curve area, however not reversing its direction of travel. Therefore even narrow curve radii can be traveled smoothly as well as without bumps. 
     Furthermore, DE 39 00 516 A1 describes a transport system with a vehicle guided by rails and a turnout. The vehicle essentially consists of a right-angle frame, whose corner areas have running gears, which can be pivoted about vertical axes. The running gears can be moved on rails located next to and at a distance from each other. The rails of different rail paths cross each other, preferably at a right angle. The crossing areas are provided with turnouts, in order to enable the vehicles to change rail paths. The turnouts essentially consist of rail sections arranged in the rails&#39; crossing points and can be pivoted about a vertical axis. 
     Transferring a vehicle from the first to the second rail path takes place after the vehicle enters the turnout by moving the rail sections, which can be pivoted. Therefore the vehicle&#39;s running gears are also pivoted by 90°, and subsequently the vehicle can move in the direction of the second rail thread. 
     The invention is based on the task of creating a transport system of the aforementioned type, which exhibits optimized applications possibilities. 
     This task of developing a transport system is accomplished with the characteristics listed in claim  1 . Advantageous design developments of the invention are noted in sub-claims  2  to  7 . 
     In accordance with the invention, the possibility of the running gears&#39; linear displacement on one side of the transport system&#39;s vehicle in transverse direction to the vehicle&#39;s longitudinal direction of travel provides that, on one hand, curves running in the vehicle&#39;s longitudinal direction of travel can be traveled and, on the other hand, turnouts known from the current state of technology and arranged in corner/cross areas can also be traveled by means of turnout rail sections, which can be pivoted about a vertical direction. Therefore the vehicles&#39; applications have been expanded. 
     Advantageous design development is achieved by locking the running gears as the vehicles travel in a transverse direction, so that the movable running gears cannot move at all during transverse travel, and therefore their track is maintained in order to enable further pivoting of the running gears by 90°, when arriving at the next turnout in a corner/crossing area. 
     An especially simple advantageous design development of the running gears&#39; retention exists with protrusions protruding to the outside from the running gears&#39; outer circumference. These protrusions abut to adjustable stop elements with the running gears pivoted in the transverse direction of travel. These stop elements are mounted on the vehicle&#39;s cross members. Due to the linear guidance of the running gears to allow their transverse displacement, a more direct introduction of forces into the vehicle&#39;s frame is possible, compared with the use of guide bars. Quiet travel without bumps is ensured, as forces are introduced into the vehicle&#39;s frame at the vehicle&#39;s corner points. 
     Construction space as well as construction height are conserved. Furthermore, as the possibility for linear displacement already disallows displacing the running gear in the longitudinal direction of travel, power locking can be dispensed with when locking for transverse travel. In especially simple cases, only the previously described protrusions and stops are required. The running gears may also be completely and easily dismounted from the transversely running guide elements as well as remounted for maintenance work. 
     Further, the use of guide rails and slide elements for the running gears&#39; transverse movement is especially advantageous in that a low push resistance also results in low steering forces. 
     This vehicle is especially suitable for use on rails whose cross sections are designed in I-shape and braced with ground supports. This transportation system is therefore suitable for traveling around stock areas, whose outline is designed mostly at a right angle, in order to pick up or drop off piece goods from individual stock areas. The invention is also suitable for vehicles and rails in the trolley conveyor area. 
     The following drawing describes a design development example of the invention in more detail. Shown are: 
     Illustration  1  top view of a transport system with a vehicle with good cornering performance on a rail section, 
     Illustration  2  side view of a vehicle with good cornering performance, 
     Illustration  3  top view of illustration  2 , 
     Illustration  4  front view of illustration  2 , 
     Illustration  5  enlarged section of the running gear area during the vehicle&#39;s longitudinal travel from illustration  3 , and 
     Illustration  6  enlarged section of the running gear area during the vehicle&#39;s transverse travel from illustration  3 . 
     Illustration  1  depicts a top view onto a transport system with vehicle  1  with good cornering performance on a section with two parallel rails  4 , which are at a distance from each other and aligned largely parallel to each other at least on their straight paths. The run of rails  2  indicates that, on one hand, corner/crossing areas  3  and, on the other hand, curve areas  4  can be traveled by vehicles  1 . The actual vehicle  1  is not obvious in illustration  1 , as skid  5  lies on each vehicle. Skid  5  transports vehicle  6 . Vehicles  1  are able to change from longitudinal direction of travel L into transverse direction of travel Q in corner/crossing area  3 . Therefore two short turnout rail pieces  7  are provided in the rails&#39; crossing points directed in longitudinal direction of travel L as well as transverse direction of travel Q. Turnout rail pieces  7  can pivot about a vertical axis and essentially by 90° from longitudinal direction of travel L into transverse direction of travel Q as well as vice versa, as required. These turnout rail pieces may be designed according DE 39 00 615 A1 referenced at the beginning. The pivoting of turnout rail pieces  7  occurs immediately after vehicle  1  with running gears  8  (see illustration  2 ) which may also pivot about vertical axes  9 , comes to a halt on turnout rail pieces  7  as soon as axes  9  of running gears  8  as well as the pivot axes of turnout rail pieces  7  align with each other. It is therefore possible that vehicle  1  arriving in longitudinal direction of travel L may leave corner/crossing area  3  in the transverse direction of travel Q by means of jointly pivoting turnout rail pieces  7  and running gears  8  by 90° each. 
     Illustration  2  depicts a side view of vehicle  1  on a straight section of rail  2 . Illustrations  3  and  4  each show a top, respectively front view of illustration  2 . Illustrations  2  to  4  subsequently describe the design development of vehicle  1  in more detail. Illustration  3  shows that the vehicle features rectangular frame  10  with four parallel side members  10   a  running at a distance as well as in longitudinal direction of travel L. Seen in longitudinal direction of travel L, side member  10   a &#39;s front and rear ends are connected with each other via two cross members  10  each. Only the two inner side members  10   a  run the entire length of vehicle  1 . 
     The two outer side members  10   a  are broken through in the area between cross members  10   b , which are arranged at a distance from each other. It is apparent that the acquired construction space is used to store running gears  11 , which are arranged in the corner points of frame  10 . Running gears  11  essentially consist of one wheel  12  (see illustration  4 ), which runs on the surface of rail  2 . Rail  2  is therefore supported via support  13  on ground  14  in a factory hall. Each castor  12  is mounted about vertical axis  9  and pivots. Illustration  2  shows that the bearing of the running gears is done via connection plate  15 , which is arranged on cross members  10   b.    
     FIG. 3 further shows that running gears  8  of vehicle  1 &#39;s left side, when seen in longitudinal direction of travel L, are additionally mounted transversely to the longitudinal direction of travel L and can be displaced. It is therefore also possible to travel through curves with vehicle  1 , whereby the axis distance of running gears  8  facing each other may change in curves, depending on the design of the run of rails  2 . In order to allow the left running gears  8 &#39;s linear possibility of transverse displacement, connection plate  5  is mounted on the top sides of cross members  10   b  via guide elements  11 . Guide elements  11  permit only one displacement of running gears  8  transverse to longitudinal direction of travel L and not in longitudinal direction of travel L. 
     FIGS. 2,  3 , and  6  furthermore show that bearing rollers  19  are provided on cross members  10   a . Skid  5  with motor vehicle  6  sits on these bearing rollers. Skid  5  is therefore kept on bearing rollers  19 , and hence on vehicle  1 , via locking, which is not depicted. The illustrations also show that the running gear is powered by drive motor  20 , which is flanged to running gear  8 . In this context, illustration  4  shows that conductor lines  21  run along the I-shaped rails. Drive motor  20  is provided with power via these conductor lines. 
     Illustrations  5  and  6  each further show an enlarged section of a running gear area from illustration  3 , when vehicle  1  is traveling in longitudinal direction, respectively in transverse direction. Illustrations  5  and  6  depict the detailed construction of guide element  11 . 
     Guide element  11  essentially consists of guide rail  11   a , which is screwed onto the top side of cross member  10   b , as well as slide elements  11   b , which embrace the guide rail, and can be displaced alongside of it. They are connected with connection plate  15  on the side opposite guide rail  11   a.    
     Illustration  5  further shows that protrusions  16  are provided alongside running gear  8 . These protrusions protrude from running gear  8 &#39;s circumferential outline. Stops  16  have no function during vehicle  1 &#39;s longitudinal direction of travel and are therefore in an idle position. Illustration  6  on the contrary shows protrusions  16 &#39;s position when in operation. Illustration  6  depicts running gear  8  during vehicle  1 &#39;s transverse direction of travel. Therefore, running gear  8  is pivoted by 90° about its axis  9 , and protrusions  16  abut to adjustable stop elements  17 , which are connected with cross members  10   b . This warrants that the possibility of compensation, respectively, transverse displacement of the running gears  8  on the left side of vehicle  1 , which is desired for vehicle  1 &#39;s travel in longitudinal direction of travel L, is canceled during transverse travel. With this arrangement working together with running gear  8 , which is traveling on rail  2  and is additionally guided along the outer sides of rail  2  by guide rollers  18 , which are mounted on the running gear about vertical axes and can be pivoted, running gear  8  is maintained in a defined position even when traveling in transverse direction Q. This is necessary, as the wheel tracks of wheels  12  may not change during entry into a subsequent corner/crossing area with turnout rail pieces  7 , which can pivot. 
     Symbol reference list 
       1  Vehicle 
       2  Rail 
       3  Corner/crossing area 
       4  Curve area 
       5  Skid 
       6  Motor vehicle 
       7  Turnable turnout rails 
       8  Running gears 
       9  Axes 
       10  Frame 
       10   a  Side member 
       10   b  Cross member 
       11  Guide element 
       11   a  Guide rail 
       11   11   b  Slide element 
       12  Wheel 
       13  Support 
       14  Ground 
       15  Connection plate 
       16  Protrusion 
       17  Stop element 
       18  Guide rollers 
       19  Bearing rollers 
       20  Drive motor 
       21  Conductor lines 
     L Longitudinal direction of travel 
     Q Transverse direction of travel