Abstract:
A fifth wheel comprises a coupling plate and at least two pillow blocks for the supported mounting of the coupling plate on a vehicle chassis of the tractor vehicle, the pillow block comprising a support region and a mounting region. The mounting region is designed for the detachable mounting of the pillow block to a transverse strut of the vehicle chassis of the tractor vehicle.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a fifth wheel, comprising a coupling plate and at least two bearing brackets for supportive mounting of the coupling plate on a vehicle chassis frame of the tractor vehicle, the bearing bracket having at least one support area and one mounting area. 
     In motor vehicle transport increasing use is being made of towing combinations having fifth wheels. The combination consists of a tractor vehicle and at least one trailer. The tractor vehicle has a coupling plate, into which a pin, the so-called kingpin, of the trailer is inserted and coupled. The coupling plate is supportively connected to the vehicle chassis frame of the tractor vehicle. The bearing brackets contain bearing elements, which allow the coupling plate to pivot transversely to the direction of travel of the tractor vehicle. 
     WO 2004/052713 A2 discloses a fifth wheel of generic type. The coupling plate is connected to the vehicle chassis frame by bearing brackets. The mounting area of the bearing bracket is laterally fixed to the vehicle chassis frame by means of bolts. The lateral forces exerted on the coupling plate by the trailer are fully absorbed by the support area of the bearing bracket. The bearing bracket itself is an integrally formed casting. 
     Proceeding from the state of the art, the object of the present invention is to specify a fifth wheel, which is as simple to manufacture as possible, which is as lightweight as possible and which can transmit the greatest possible forces between the trailer and the tractor vehicle. 
     SUMMARY OF THE INVENTION 
     The object is achieved by a fifth wheel comprising a coupling plate and at least two bearing brackets for supportive mounting of the coupling plate on a vehicle chassis frame of the tractor vehicle, the bearing bracket having a support area and a mounting area, the mounting area for detachable mounting of the bearing bracket being formed on a transverse strut in the vehicle chassis frame of the tractor vehicle. 
     It is advantageous for the vehicle chassis frame itself to be strengthened, rather than weakened, by the attachment of the fifth wheel. This is achieved in that the mounting area of the bearing bracket is designed for detachable mounting on a transverse strut of the vehicle chassis frame. This is also achieved in that the mounting area is formed on a gusset plate between the transverse strut and the vehicle chassis frame. Attaching the fifth wheel directly to the vehicle chassis frame achieves a direct and precisely defined direction of the trailer forces acting on the tractor vehicle. 
     It is also advantageous for the mounting of the bearing bracket to be as easily fitted and detached as possible. This is achieved in that the transverse strut is embodied as a U-profile member. 
     It is furthermore advantageous for the forces that have to be transmitted between the tractor vehicle and the trailer, and vice versa, to be introduced as directly as possible into the vehicle chassis frame of the tractor vehicle. This is achieved in that the mounting area of the bearing bracket has a U-shaped foot section, the legs of the U-shape being designed to interlock positively around the transverse strut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Three exemplary embodiments of the invention will be described with reference to the drawings, in which: 
         FIG. 1  shows a perspective view of a fifth wheel according to the invention with different left and right-hand variants of the attachment, 
         FIG. 2  shows a view of the fifth wheel in  FIG. 1 , viewed in the direction of travel, 
         FIG. 3  shows a section through a fifth wheel according to the first variant of the attachment, 
         FIG. 4  shows a section through a fifth wheel according to the second variant of the attachment, 
         FIG. 5  shows a further perspective view of the fifth wheel in  FIG. 1 , 
         FIG. 6  shows a view of the fifth wheel in  FIG. 3 , viewed from above and 
         FIG. 7  shows a further view of a fifth wheel with a gusset plate for the direct attachment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a perspective, schematic representation of a fifth wheel  1 . In  FIG. 1  the fifth wheel  1  is represented with two different exemplary embodiments of the attachment. The fifth wheel  1  comprises a coupling plate  2  with an insertion opening  4  for the kingpin of the trailer, which has not been shown here. The coupling plate  2  is supportively mounted on two bearing brackets  5 . The bearing bracket  5  serves for supportive seating of the coupling plate  2  and for detachable mounting on a vehicle chassis frame. The bearing bracket  5  comprises an upper support area  6  and a lower mounting area  7 . In  FIG. 1 , two sections  8  of the longitudinal members of the vehicle chassis frame are shown running in the direction of travel. A transverse strut  9  is arranged between the sections  8  of the longitudinal members of the vehicle chassis frame. 
     To facilitate comparison of the two exemplary embodiments, the bearing bracket  5  and the transverse strut  9  are represented differently on the left-hand side and on the right-hand side of the vehicle chassis frame  8 , viewed in the direction of travel. In reality, the transverse strut  9  is of identical design on left and right-hand sides and the bearing brackets  5  are identical or mirror symmetrical. A completely identical design of the left-hand and right-hand bearing brackets  5  is advantageous, because the two parts are interchangeable and only one part has to be manufactured during production. The transverse strut may also be designed with any other cross-section, for example as a casting or formed part made from sheet steel. 
       FIG. 2  shows the fifth wheel in  FIG. 1  again, viewed in the direction of travel. On the left-hand side the bearing bracket  5  is formed with a T-shaped foot section  10 . The web  11  of the T-shaped foot section  10  rungs horizontally and parallel to the upper side of the transverse strut  9 . On the left-hand side the transverse strut  9  is formed as a double T-profile member  12 . 
     On the right-hand side the bearing bracket  5  is formed with a U-shaped foot section  13 . The transverse strut  9  is likewise designed as a U-profile member  14 . The legs  15 ,  16  of the U-shaped foot section  13  grip with a positive interlock around the U-profile member  14 . In the U-shaped configuration of the foot section  13  and the transverse strut  14 , the bearing faces between the bearing bracket and the transverse strut are larger than in the case of the T-shaped design. The detachable attachment between the coupling plate  2  and the vehicle chassis frame  8  is made by bolts  17  and holes  18 , which are disposed running in the direction of travel. The forces acting on the fifth wheel  1  when in motion can be distributed over a larger acting area and over more bolted connections. Because a larger area is available, this type of attachment can be more readily adapted to different types of vehicle chassis frame  8 . 
     In  FIGS. 3 and 4  the fifth wheel  1  is shown divided along the center line in the direction of travel. In  FIG. 3  the fifth wheel  1  is shown according to a first exemplary embodiment with U-shaped members  13 ,  14 , and in  FIG. 4  the fifth wheel is shown according to the second exemplary embodiment with T-shaped members  10 ,  12 . 
       FIG. 5  again shows a perspective view of the fifth wheel  1  in  FIG. 1  from the underside of the vehicle chassis frame  8 . A mounting point  19  for the suspension of the rear axle is shown on the U-profile member  14 . 
       FIG. 6  shows the right-hand half of the fifth wheel  1  viewed from above. It can be seen from  FIG. 6  how the foot section  13  with the legs  15 ,  16  of the bearing bracket  5  positively interlocks around the U-profile member  14  and how the bolts  17  and holes  18  are arranged on both sides of the U-shaped transverse strut  14 . 
       FIG. 7 , in a further exemplary embodiment, shows how the mounting area  7  is connected to a gusset plate  20  between the transverse member  14  and the vehicle chassis frame  8 . The T-shaped foot section  10  is connected by means of bolts  21 ,  22  both to the transverse strut  14  and to the gusset plate  20 . The gusset plate  20  itself may be welded to the vehicle chassis frame  8 . 
     Overall, the attachment of the fifth wheel  1  to a transverse strut  9 ,  12 ,  14  in the vehicle chassis frame  8  is easy to make, it is capable of absorbing large forces and it can be adapted to different types of vehicle chassis frame  8 .