Abstract:
A sports device ( 10 ), preferably a snow or water vehicle, has an outer shell ( 15 ) which when inflated, forms a support surface ( 13 ) underneath and a lying down or sitting surface ( 20 ) on top. An inflatable tubular shell ( 20 ) with two segments ( 21, 22 ) extending crosswise across it is provided in this outer shell ( 15 ). The outer shell ( 15 ) is formed of a robust fabric which is coated or laminated with plastic. The tubular shell ( 20 ), which is in itself separate from the outer shell, is produced from plastic films, preferably without any fabric reinforcement. The outer shell may also be connected to the tubular shell in such a way that they form a single film. The sports device can therefore be produced with optimal materials for the outer shell or the tubular shell, with the result that it has a long service life.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a sports device, preferably a snow or water vehicle, which can be inflated with a medium, especially air, and which comprises an outer shell, which when inflated forms a support surface underneath and a lying or sitting surface on top. 
   A generic sports device according to the document DE-A-34 34 384, which relates to an air-cushion toboggan, provides four longitudinal rolls arranged side by side, which can be inflated with air. The rolls at the two outer sides are parallel to one another at the rear end and arranged conically at the front, tapering inwards towards a point, while the two inner rolls extend in the longitudinal direction of the toboggan, and, in this context, serve as the sitting area of the toboggan. The outer rolls are each fitted with guide runners underneath, which taper at the front towards a point. Furthermore, handles, which the driver can hold during travel, are fitted to the upper side of the outer rolls. 
   One problem with this toboggan relates to its manufacture wherein it is necessary to ensure that the rolls are manufactured from a sufficiently rigid material. Because, if the toboggan were to travel over an object, for example a protruding, pointed stone, a hole could quickly appear in the shell affected and the air pressure provided would immediately decline. Accordingly, the toboggan could only be driven with difficulty or not at all. A further disadvantage is that during travel, the driver must displace his weight to the outer side of the toboggan in order to make a curve. Because of the centrifugal force acting on the driver when travelling in a curve, there is a risk that he may fall sideways from the toboggan. 
   SUMMARY OF THE INVENTION 
   The present invention is therefore based upon the object of creating a sports device of the type mentioned in the introduction, which is constructed with increased safety and corresponding strength with the purpose of providing a longer service life. Furthermore, the present sports device should provide improved steering capability. 
   This object is achieved according to the invention in that an inflatable tubular shell is integrated inside the outer shell, which is either at least partially separate or connected to the outer shell, and that at least one connecting segment extending crosswise through it is provided, which connects the lower support surface to the lying or sitting surface located above it. 
   By providing the outer shell and the tubular shell contained inside it, the sports device according to the present invention creates the substantial advantage that the outer shell can be made from a material, which is very resistant to contact with solid objects and to frictional wear, and furthermore, as an advantage in manufacturing, can be fitted without difficulty with accessory components such as runners, handles, eyelets etc. 
   By contrast, the inner tubular shell, which advantageously is formed of a single film together with the outer shell, can be fitted with a material specific for its purpose. Accordingly, this device can also be fitted with runners to allow very simple and effective steering. 
   In one very advantageous embodiment, the outer shell and tubular shell, manufactured in each case from an upper and a lower film layer, are welded together around the lateral perimeter by means of a continuous seam, whereby the outer shell comprises a robust fabric, which is coated or laminated with a synthetic material, while the tubular shell comprises a synthetic film. Accordingly, optimum conditions are provided for a safe sports device with a long service life. 
   Further embodiments of the invention and additional advantages will be presented below with reference to the drawings. The drawings are as follows: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a sports device according to the present invention; 
       FIG. 2  is a cross-sectional view through the sports device according to  FIG. 1  along the line II—II; 
       FIG. 3  is a bottom plan view of the sports device according to  FIG. 1 ; 
       FIG. 4  is a partial cross-sectional view of the outer shell with a support surface and attachable runners as a design variant; 
       FIG. 5  is a cross-sectional view through a sports device in a design variant in which the outer shell and the tubular shell consist of a single film; and 
       FIG. 6  is a partial longitudinal section through the sports device according to  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a sports device  10 , which, in the present embodiment, is especially designed as a toboggan, but could essentially be used as any desired snow vehicle or water vehicle. This sports device  10  is inflated with a medium, especially air, and comprises an outer shell  15 , which when inflated forms a lower support surface  13  and an upper lying or sitting surface  12 . 
   In  FIG. 2 , an inflatable tubular shell  20  is provided according to the invention with two connecting segments  21 ,  22  extending crosswise through it. The connecting segments connect the lower support surface  13  to the upper lying or sitting surface  12  of the outer shell  15  in order to limit the spacing and provide shape to the outer shell. 
   The outer shell  15  and the tubular shell  20  are each manufactured from two correspondingly dimensioned pairs of film  15 ′,  20 ′;  15 ″,  20 ″, one of which forms the upper side and the other forms the lower side of the device  10 . The two-part tubular shell  20 , with its film layers  20 ′,  20 ″, is of approximately the same dimensions as the associated film layers  15 ′,  15 ″ of the outer shell  15 . These superimposed film pairs  15 ′,  20 ′;  15 ″,  20 ″ are welded together at the lateral perimeter by means of a continuous seam  16 , so that an enclosed chamber is formed inside the tubular shell  20 . 
   The outer shell  15  is made from a robust fabric, which is coated or laminated with an appropriate synthetic material, and the tubular shell  20 , which is per se separate from the latter is made from at least one synthetic-material film. The upper film  15 ′ of the outer shell  15  comprises a rough outer surface, so that a person seated on it will not slip. The inside of this film  15 ′ is coated or laminated with a synthetic material, so that it can be welded together with the per se separate tubular shell  20  and the lower film. 
   The lower film  15 ″ is also manufactured from a robust fabric, which is coated or laminated on both sides with a synthetic material. The inside of the lower film is preferably coated or laminated with the same synthetic material as the inside of the upper film  15 ′. The lower side of the lower film  15 ″ is coated or laminated with a synthetic material providing very good gliding properties, so that the sports device glides well on snow or water. 
   In one very advantageous embodiment, the upper film  15 ′ of the outer shell  15  comprises a GORE-TEX® CORDURA® fabric coated with polyurethane TPU and/or a nylon fabric, while the lower film  15 ″,  55 ″ is manufactured from a robust KELVAR® (poly-paraphenylene terephthalamide), TELFON® (polyterafluoroethylene) or nylon fabric. The interior side of both films are coated or laminated with polyurethane TPU. The outer side of the upper film which forms the sitting surface is uncoated, while the outer side of the lower film  15 ″,  55 ″ which forms the gliding surface, is coated or laminated with a PVC or TPU synthetic material provided with good gliding properties. The tubular shell  20  is manufactured from polyurethane TPU preferably without additional fabric. This combination of materials provides, in particular, the advantage that the two different shells can be very readily welded together. Of course, other materials, which fulfil the required properties for this sports device  10 , may in principle also be used. 
   Within the context of the invention, two connecting segments  21 ,  22  running approximately symmetrical to the longitudinal central axis of the outer shell  15  are provided. Each of these connecting segments  21 ,  22 , which are also manufactured from a synthetic material corresponding to the fabric coating, is welded together to form the support surface  13  underneath and the seating surface  12  on top of the outer shell  15  and the tubular shell  20 , in each case forming a longitudinal seam  17 ,  18 , thereby creating one longitudinal roll in the center and one at each outer side. In accordance with  FIG. 1 , a continuous longitudinal seam  17 ,  18  results in a uniform, straight dividing line between the rolls. 
   The connecting segments  21 ,  22  are formed approximately along the entire length of the outer shell  15 . However, a connection between the individual chambers  26  is provided at the front and the back, so that only one valve  14  is required for inflation and deflation with air. This provides the further advantage that when the driver shifts his weight, the air can escape into the unloaded chambers. In principle, however, the three chambers  26  could be separated from one another, and a separate valve  14  could be allocated to each one. 
   When welding together the film layers  15 ′,  15 ″;  20 ′,  20 ″ and the connecting segments  21 ,  22 , the connections through the longitudinal seams  17 ,  18  are produced first; and the seam  16  at the outer perimeter is only produced after this, advantageously by means of a known high-frequency electrical welding technique. 
   When inflated, the outer shell  15  forms a mattress shape, as shown in  FIG. 1 , and in this context tapers laterally towards the front. Moreover, a handle  11  is attached at each side. This provides the further advantage that, any accessory components such as handles  11 , eyelets, pockets and other features can be attached to this outer shell  15 , without the occurrence of problems relating to sealing, because the tubular shell is separate from these accessory components. Only the valve  14  extends through the outer shell into the tubular interior. 
   The materials for the outer shell  15 , the tubular shell  20  and connecting segments  21 ,  22  are designed to be flexible so that the device  10  can readily be folded and stored, for example, in a rucksack. 
     FIG. 3  shows the sports device  10  from below, illustrating its runners  31 ,  32  arranged in the longitudinal direction, and attached to the support surface  13  of the outer shell  15 . The two outer runners  32  are not straight, but are curved outwards with a radius R. Accordingly, the driver can shift his weight to the inner side of the toboggan thereby producing increased pressure on one of these two runners  32 . This slightly tapering design of the runners  32  allows the toboggan to produce curves as it were automatically when the weight is shifted to one or the other of these runners. The radius R is preferably on the order of magnitude between 5 and 20 meters. 
   In accordance with  FIG. 4 , as a design variant, a profiled plate  35  with several T-grooves  36  arranged adjacently for retaining the runners  37  is welded onto the support surface  13  of the outer shell  15 . This illustrates that with the design of the device according to the invention, various solutions can be implemented depending on requirements. 
     FIG. 5  shows a sports device  50 , which is essentially constructed in the same manner as that shown in  FIG. 1 . For this reason, the same reference characters are used to refer to the same components. By contrast with the design according to  FIG. 1 , an outer shell  55  and a tubular shell  60  are provided; these are connected to one another and form a single film. Again, an upper and a lower film are provided, which are welded together laterally by means of an overlap  56 . 
   In accordance with  FIG. 6 , the outer shell  55  is manufactured from a robust fabric, which, again, is coated or laminated with synthetic material. For this purpose, the upper film  55 ′ comprises a rough outer surface with the robust fabric  56 . On the inside  57 , it is coated or laminated with synthetic material and thereby forms the tubular shell. The lower film  55 ″ is also made from the robust fabric  56 , moreover, coated or laminated on the inside  58  with synthetic material to form the tubular shell, and provided with the appropriate, synthetic material offering good gliding properties on the outside  59  to form the gliding surface. 
   Moreover, in the case of this sports device  50 , it is advantageous for a separate piece of film  52 ,  53  to be attached, especially welded, in each case to the inside of the tubular shell  60  at all positions, at which accessory components, such as runners, handles  11 , eyelets or the valve are attached to the outer shell  55 , so that an additional seal is provided at these positions. 
   This sports device is preferably used as a toboggan, which can be steered very easily and is also suitable for deep snow. 
   With reference to the exemplary embodiments described above, the invention has been adequately explained. However, it could be presented in still further variants. In principle the tubular shell could also be manufactured completely separately from the outer shell and inserted into the latter and advantageously attached to it. 
   Furthermore, only one or more than two crosswise-extending connecting segments could be provided inside the tubular shell  20 . 
   The outer shell and also the tubular shell could in each case comprise a sock-shaped shell only being connected together at the front and the rear. Also, their outer shape could, of course, be designed differently from the examples presented, for instance, being rounded, oval, elliptical or similar shape.