Abstract:
A bellows for a gangway of an articulated vehicle, the articulated vehicle having at least two articulately connected vehicle parts, and has an elastic sheath on its outer side.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application is the U.S. national phase and claims priority to DE 20 2013 000 165.8, filed Jan. 9, 2013, the contents of which are incorporated herein in their entirety. 
       FIELD OF THE INVENTION  
       [0002]    The invention relates to a bellows of a gangway for an articulated vehicle of the type having at least two articulately connected vehicle parts, such as a rail vehicle or an articulated bus. 
         [0003]    A vehicle for public passenger transport with such a bellows is also an object of the invention. 
       BACKGROUND OF THE INVENTION  
       [0004]    In a road or rail vehicle, a gangway has at least one bellows and a platform and bridge enclosed by the bellows in the manner of a tunnel, which allows persons to move from one vehicle part of an articulated vehicle to the other. In articulated busses, more specifically, the bellows not only encloses the platform but also the pivot joint between the vehicle parts. 
         [0005]    In high speed trains, more specifically, an inner and an outer bellows are provided as part of the gangway between the two articulately connected vehicle parts, the outer bellows enclosing the inner bellows in a spaced relationship. Such a construction is chosen in order to absorb the considerable pressure surges occurring e.g. when entering a tunnel with regard to the interior space. A disadvantage of the known design of two bellows mounted inside each other is that the outer bellows is placed at a considerable radial distance from the car body wall, which leads to the formation of vortices in the area of the bellows, more specifically at high speeds, which has a negative effect on the aerodynamics of the train. In this respect, EP 2 353 894 A1 not only discloses circumferentially disposing the outer bellows in the area of the respective car body wall of two articulately connected vehicles but also providing a corrugated bellows in a neutral position of the bellows, i.e. when the two vehicles are located in one plane, the wavelike, U-shaped bellows elements of which have a substantially perpendicular cross-section with a planar web, thus resulting in a substantially completely flat outer wall of the corrugated bellows during straight ahead travel. This means that substantially no or only minor vortices are formed as opposed to when the bellows elements forming the corrugated bellows are indeed wave-shaped, i.e. have a rounded contour in a cross-sectional view. 
         [0006]    However, with such bellows, the bellows elements of which have a substantially rectangular cross-section, vortices are immediately formed when such vehicles or trains drive through a narrow bend, since gaps appear between the individual bellows elements on the outer side of the bend. The bellows is compressed on the inner side of the bend, so that the bellows elements bulge slightly outward in the area of the web. 
       SUMMARY OF THE INVENTION  
       [0007]    The problem to be solved by the invention is therefore to avoid the formation of vortices on the outer side of the bellows irrespective of the respective driving situation, i.e. irrespective of whether the train travels straight ahead or through a bend. 
         [0008]    In order to solve the problem, it is proposed according to the invention that the bellows has an elastic sheath on its outer side, the elastic or flexible sheath preferably resting on the bellows. This means that the sheath encloses the bellows in the manner of a stocking. It is more specifically provided that the elastic or flexible sheath rests on the bellows under tension, i.e. in a stretched state. The extent of the elongation is hereby advantageously chosen so that the sheath on the bellows does not form any creases on the inner side of the bend. 
         [0009]    In this context, if one imagines that the bellows consists of individual wave-shaped bellows elements, i.e. elements, the cross-section of which is substantially characterized by a round outward bulge, the sheath covers the wave-shaped outer contour of the bellows, with the consequence that the bellows appears outwardly as a completely flat structure. The formation of vortices is thus avoided. Such a sheath is usable not only with corrugated bellows but also with folded bellows. 
         [0010]    The sheath is formed by an elastic or flexible material, the sheath being extensible in the direction of the longitudinal axis and/or transversely to the longitudinal axis of the sheath. From this it is clear that the sheath, that advantageously extends along the entire length of the bellows and also advantageously completely encloses the bellows along its circumference, is more specifically tensioned in the longitudinal direction of the vehicles in such a manner that when driving through a bend, no creases are formed in the sheath even on the side of the bellows located on the inner side of the bend. The elasticity is calculated in such a manner that the sheath is not damaged by overextension on the outer side. In addition, the sheath can also rest on the bellows under radial tension. In this context, it has turned out to be more specifically advantageous if a fabric is used as a material for the sheath that is formed by a woven fabric, a warp-knitted fabric or a weft-knitted fabric. The elasticity of a warp-knitted or weft-knitted fabric is the direct consequence of the fact that it is knitted. However, as in the case of a woven fabric, the threads or yarns can also be made of an elastic material, i.e. they can have a certain degree of elasticity. In this context it is more specifically provided that threads of reticulated silicone rubber can be used for the fabric, which have elastic modulus values ranging from 20 to 100 cN/800%, more specifically ranging from 20 to 80 cN/100%. In a woven fabric, the warp and weft threads can both be made from such an elastic material. However, if it should be sufficient to provide elasticity in only one direction, it is also possible to design either the warp or the weft threads as elastic threads in the above sense. 
         [0011]    According to another feature, the sheath is adapted to be fastened to the bellows. At high speed the sheath tends to lift off the bellows due to suction, which means that the sheath bulges outward. In order to prevent such a bulging, it is provided according to another feature of the invention, that the sheath is adapted to be fastened to the bellows. This means that the sheath is not only fastened to the bellows or the respective car body at its ends, i.e. in the area of the front side of the car bodies, but that there can also be a connection with the bellows along the entire length of the sheath. In this respect, it can be provided to connect the sheath to the bellows in the area of each corrugation or pleat, or to provide a connection to the sheath for example only on one in two or one in three corrugations or folds. 
         [0012]    According to another feature, the sheath is adapted to be fastened on the bellows. At high speed the sheath tends to lift off the bellows due to suction, which means that the sheath bulges outward. In order to prevent such a bulging, it is provided according to another feature of the invention, that the sheath is adapted to be fastened on the bellows. This means that the sheath is not only fastened to the bellows or the respective car body at its ends, i.e. in the area of the front side of the car bodies, but that there can also be a connection with the bellows along the entire length of the sheath. In this respect, it can be provided to connect the sheath to the bellows in the area of each corrugation or pleat, or to provide a connection to the sheath for example only on one in two or one in three corrugations or folds. 
         [0013]    A vehicle for public passenger transport, characterized by a bellows according to the invention is also an object of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    In the following, the invention is explained in more detail based on the drawings. 
           [0015]      FIG. 1  is a schematic showing a two-part vehicle, the two vehicle parts being connected by a gangway with a bellows. 
           [0016]      FIG. 2  is a cross-sectional view taken along line II-II in  FIG. 1 ; 
           [0017]      FIG. 3  is a cross-sectional view taken along line in  FIG. 2 ; 
           [0018]      FIG. 4  is a schematic showing the gangway in a perspective view. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    An articulated vehicle  3  formed by two articulately connected vehicle parts  1  and  2  includes a gangway  10 . A pivot joint or coupling  5  is located under the gangway  10  connecting the two vehicle parts  1  and  2 . 
         [0020]    The object of the invention is the configuration of the outer bellows  14  of the gangway  10 . In this context, reference is first made to  FIG. 2  which shows a section according to line II-II in  FIG. 1  and in which the inner bellows  11  and the outer bellows  14  are recognizable. The outer bellows  14  extends in the area of the lateral walls and of the roof in such a manner that it follows the course of the contour of the car body of vehicle part  2 . 
         [0021]      FIG. 2  also shows the gangway bridge or platform  12  inside the inner bellows  11  which allows persons to move between the vehicle parts  1  and  2 . 
         [0022]    The object of the invention is the configuration of the outer bellows  14  according to  FIG. 3 , the inner bellows  11  being left out for more clarity. The outer corrugated bellows  14  is composed of individual wave-shaped bellows elements  15  that are connected to each other by bellows frames  15   a.  The outer bellows  14 , which is fastened at its ends to the car bodies of the two vehicle parts  1  and  2 , is enclosed by a sheath  20  that is formed by an extensible fabric. The sheath is extensible in the direction of the longitudinal axis of the bellows or of the sheath as well as in the transverse direction relative to the longitudinal axis of the bellows or of the sheath according to the arrows  25 . This means that the sheath  20  is pulled under tension over the outer bellows like a stocking and is connected to the bellows in the area of the crests of the individual wave elements by webs  16 . The webs  16  for connecting the sheath  20  to the bellows are provided on the circumference of the bellows at determined intervals. The length of the webs is variable. The length of the webs advantageously tends towards zero, i.e. the web connects the hull directly to the bellows. The web  16  can hereby be formed by sewing or gluing. 
       LIST OF REFERENCE NUMBERS  
       [0023]      1  vehicle part 
         [0024]      2  vehicle part 
         [0025]      3  articulated vehicle 
         [0026]      5  pivot joint or coupling 
         [0027]      10  gangway 
         [0028]      11  inner bellows 
         [0029]      14  outer bellows 
         [0030]      15  wave-shaped bellows element 
         [0031]      15   a  bellows frame 
         [0032]      16  web 
         [0033]      20  elastic sheath