Abstract:
A roof box for a vehicle, the roof box including a base portion with a load receiving area. The base portion is adapted to be positioned in the proximity of a roof of a vehicle. A closable lid or net is adapted to retain cargo on the load receiving area of the base portion. The base portion of the roof box includes a load stop. The load stop of the base portion effectively prevents, or at least reduces the risk of cargo, such as skis or the like, from penetrating through the roof box in case of a collision or crash.

Description:
FIELD 
       [0001]    A roof box for a vehicle comprising a safety arrangement to prevent load from escaping the roof box in case of an accident or a sudden retardation of the vehicle. 
       BACKGROUND 
       [0002]    Roof boxes are generally used to transport luggage, cargo, or other objects usable to man, by mounting the roof box on the roof of a vehicle, usually via a roof rack. Roof boxes can be manufactured in a wide variety of materials although thermoplastics are the most common material used up to date. One way of manufacturing a roof box is to form mold a base portion and a lid as separate pieces, and thereafter pivotally connect the lid to the base portion to form a closeable confided luggage and storage compartment. As a consequence of the manufacturing method, the stability and strength of the roof box has generally been limited to the stability and strength of the form molded pieces themselves. 
         [0003]    Although roof box manufacturers has developed roof boxes which meet high requirements concerning safety, stability and strength, there are situations which cannot be fully anticipated and which impose structural demands to the roof box which are difficult to predict or meet. One such situation is a crash scenario, in which the vehicle crashes or collides with another object. Objects which are not sufficiently secured inside of the roof box, e.g. by using cargo nets or straps or the like, can accidentally be forced through the roof box wall and out to the ambient environment, due to their inherent inertia during a crash or collision. This is especially the case for relatively heavy sports equipment such as skies or snowboards. 
         [0004]    The published document DE 202008000734U1 disclose a roof box with an absorbing member adapted to absorbed the kinetic energy which an object has during a crash, to prevent the object from escaping or damaging the roof box. The absorbing member has a bow shaped form and is attached to the side walls of the base portion using screws. The solution is however not very efficiently dispersing the absorbed kinetic energy into the base portion as might be wanted. 
       SUMMARY 
       [0005]    It is an object of the present invention to remove, or reduce the drawbacks of the above mentioned prior art, or to at least find a useful alternative. The objects are at least partly met by a roof box for a vehicle. The roof box comprises a base portion comprising a load receiving area and is adapted to be positioned in the proximity of a roof of a vehicle. A closable lid or net is adapted to retain cargo on the load receiving area of the base portion. The base portion of the roof box comprises a load stop comprising a floor portion, wherein the floor portion is adhered to the load receiving area of the base portion. 
         [0006]    The roof box has the advantage of not require any structural weak points, such as screw holes, in the base portion. It further transfers any kinetic energy imparted to the load stop from a displaced object inside of the roof box, in an advantageous manner, as the whole adhered surface transfers force to the base portion of the roof box. Furthermore, as the floor portion of the load stop is at least adhered to the load receiving area of the base portion, it is a very robust solution. 
         [0007]    According to an aspect, the roof box comprises a front end and a rear end, the load stop is positioned in the front end of the roof box and/or in the rear end of the roof box. The roof box can thus be reinforced and prepared for front collisions and/ or rear collisions. 
         [0008]    According to an aspect, the floor portion of the load stop has an area of from 3-20%, advantageous of from 5-15% of the load receiving area of the roof box. A large floor portion area of the load stop permits kinetic energy imparted from an object during a collision to be easily transferred to the underlying load receiving area and the base portion of the roof box. 
         [0009]    According to an aspect, the base portion comprises a periphery wall, and in that the load stop is further adhered to the periphery wall of the base portion of the roof box. Additional strength and stability is provided by adhering the load stop to the periphery wall. 
         [0010]    According to an aspect, the load stop is manufactured from a first material and the base portion of the roof box is manufactured from a second material, the first material being different from the second material. The load stop can be manufactured from a first thermoplastic material, and the base portion can be manufactured from a second thermoplastic material for example. The load stop is advantageously manufactured from a thermoplastic which is at least more rigid than the base portion as it is believed that this assists in transferring imparted forces from the load stop to the base portion. 
         [0011]    According to an aspect, the thermoplastic material which the load stop can be manufactured from is selected from the list of polycarbonates (PC), polymethyl methacrylate (PMMA), Acrylonitrile butadiene styrene (ABS), Polypropylene (PP), Polystyrene (PS), Polysulfone (PSU), Polytrimethylene terephthalate (PTT), Polyurethane (PU), Polyvinyl chloride (PVC), Polyvinylidene chloride (PVDC), Styrene-acrylonitrile (SAN), polyphenylene (SRP), or the like, or mixtures thereof. 
         [0012]    According to an aspect, the thermoplastic material which the load stop is manufactured from has a tensile strength of at least 40 MPa as measured by ASTM D 638. In an embodiment, the tensile strength of the thermoplastic which the load stop is manufactured from is higher than the tensile strength of the thermoplastic material which the base portion is manufactured from. 
         [0013]    According to an aspect, the load stop comprises a floor portion adhered to the load receiving area of the base portion, a roof portion, and a first and a second side wall extending between the floor portion and the roof portion of the load stop and a front portion. The floor portion, roof portion, front portion and the first and the second side wall defines a load receiving void with an opening. 
         [0014]    According to an aspect, the load stop is adhered by means of an adhesive selected from the list of: pressure sensitive adhesives, contact adhesives, hot adhesive or hot melt adhesives, reactive adhesives one part, two parts or the like, synthetic adhesives or the like, or mixtures thereof. 
         [0015]    According to an aspect, the load stop is adhered by means of an adhesive selected from the list of: Cyanoacrylate, Polyurethane, Epoxy and/or Acrylic adhesive. 
         [0016]    According to an aspect, the load stop is adhered using an intermittent adhesive pattern. 
         [0017]    The load stop which is adhered to the base portion is effectively preventing, or at least reducing the risk of, objects, such as skies, snowboards, or the like, from penetrating through the roof box in case of a collision or crash, i.e. a heavy retardation of the vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Non-limiting embodiments of the present invention are described in greater detail with reference to the accompanying Figures. 
           [0019]      FIG. 1  shows a roof box comprising a base portion, a lid and a load stop, shown in perspective and with a view into onto the load receiving area of the roof box. 
           [0020]      FIG. 2  shows a cross section of the roof box of  FIG. 1  along the line A-A. 
           [0021]      FIG. 3  shows the front end of the roof box of  FIG. 2  in greater detail with the load stop transparently illustrated, and an adhesive pattern by which the load stop is adhered to the base portion of the roof box. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  shows a roof box  1  adapted to be attached to a roof  2  of a vehicle  3 , directly or via a roof rack arrangement  4 . The roof rack arrangement  4  is of conventional type and will not be described further herein. The roof box  1  comprises a base portion  10  adapted to be positioned in the proximity of the roof  2  of the vehicle  3 , a closeable lid  11  hereafter only referred to as the lid  11 . The lid  11  is pivotally connected to the base portion  10  via hinges (not shown). Other attachment means, instead of hinges, are possible such as straps, slide rails or flexible sections or the like. The lid  11  could in one embodiment be fully detachable form the base portion  10 . In an embodiment, the lid  11  can be replaced by a cargo net, or a flexible cover, or similar, although a lid is preferable. 
         [0023]    The base portion  10  comprises a periphery wall  13  defining a load receiving area  20  within the space formed but the periphery wall  13 . The lid  11  comprises a rim  14  which engages the periphery wall  13  of the base portion when closed, to enclose any objects positioned in the roof box  1 . The roof box  1  further has a front end  5  and a read end  6 . The front end  5  is intended to point in the primary direction of travel, i.e. towards the front of the vehicle  3 , while the rear end  6  is intended to point to the rear of the vehicle  3 . 
         [0024]    The base portion  10  of the roof box  1  comprises channels  21  and ridges  22  which extend along the longitudinal direction of the roof box  1  to provide a rigid base portion  10 . 
         [0025]    The base portion  10  comprises a load stop  30 . The load stop  30  is intended to prevent any objects positioned in the roof box  1  from penetrating through the front end  5  of the roof box  1  and escape to the ambient environment in case of an accident such as a vehicle crash, vehicle collision or the like, or in case of heavy and/or sudden retardation of the vehicle. 
         [0026]      FIG. 2  shows a cross section along the line A-A of  FIG. 1  and with the front end  5  of the rood box in greater detail.  FIG. 2  shows parts of the base portion  10 , parts of the lid  11 , the load receiving area  20  and the load stop  30 . The load stop  30  comprises a floor portion  31 , a roof portion  32 , a first side wall  33  arranged opposite a similar side wall  34  (not shown in  FIG. 2 ). The load stop further comprises a front wall  35  and an opening  36 . The floor portion  31 , the roof portion  32 , the first and the second side wall  33 ,  34  and the front portion  35  defines a load receiving void  40 . The opening  36  is positioned towards the rear end  6  of the roof box  1 , and is intended to catch any loose objects sliding in the roof box  1  in a bucket like manner. It is of course possible that the load stop  30  simply braces the load inside of the roof box  1 . 
         [0027]    As is notable, the floor portion  31 , the roof portion  32 , the first and the second side wall  33 ,  34  and the front portion  35  has a form and shape which substantially corresponds to the interior form and shape of the base portion  10  and the lid  11  at the front end  5  of the roof box  1 . In an embodiment, at least the floor portion  31  has a shape and form which corresponds to the shape and form of the load receiving area  20  at the front end  5  of the base portion  10  of the roof box  1 . 
         [0028]    In the shown embodiment, the load stop  30  is formed in one unitary piece of material which has been adhered to the base portion  10  of the roof box  1 , and specifically the load receiving area  20  of the base portion  10  of the roof box  1 . The area of the floor portion  31  is substantially 10% of the load receiving area  20  of the base portion  10 . The load stop  30  can thus be adapted to cover from 3-20%, advantageous from 5-15% of the load receiving area  20  of the roof box  1 . 
         [0029]    In an embodiment, the load stop  30  can be formed by at least two individual sections which together form a load stop. A first section can be arranged to the lid  11  and a second section can be arranged to the base portion for example. In the latter embodiment, when the lid  11  is closed, the load stop forms a load receiving void. 
         [0030]    An advantage of having a load receiving void formed by a floor portion  31 , a roof portion  32 , a first and the second side wall  33 ,  34  and a front portion  35  is that the forces imparted to the load stop  30  by the inherent kinetic energy of an object, in case of a collision or similar, is spread or dispersed in an advantageous manner. Further, as the load stop  30  is positioned substantially adjacent the lid  11  of the roof box  1 , and the periphery wall  13  of the base portion  10 , and attached to the base portion  10  of the roof box  1 , if the load stop  30  is temporarily deformed, the adjacent section of the roof box  1  will effectively support the load stop  30  from further deformation and act as a support element to the load stop  30 . 
         [0031]    In the shown embodiment of  FIG. 2 , it can be noticed that the front wall  35  has a height H 1  and the opening  36  of the load stop  30  has a height H 2 . The H 1  of the front wall  35  is smaller than the height H 2  of the opening  36  of the load stop  30 . Even if the load stop itself would be disconnected, or disengaged from the base portion  10  of the roof box, its wedge like form would wedge the load stop between the base portion  10  and the lid  11 . The rigidity of the load stop  30 , formed by the first and the second side wall  33 ,  34  thus provides for an additional safety function in case of an accident of crash or similar. 
         [0032]    It has been found that the load stop according to any embodiment disclosed herein can be formed by a thermoplastic material such as polycarbonates (PC), polymethyl methacrylate (PMMA), Acrylonitrile butadiene styrene (ABS), Polypropylene (PP), Polystyrene (PS), Polysulfone (PSU), Polytrimethylene terephthalate (PTT), Polyurethane (PU), Polyvinyl chloride (PVC), Polyvinylidene chloride (PVDC), Styrene-acrylonitrile (SAN), polyphenylene (SRP), or the like, or mixtures thereof. 
         [0033]    In some embodiments it can be advantageous to choose a thermoplastic having a medium tensile strength (measured by ASTM D 638). By medium tensile strength is meant a tensile strength of 40 MPa or more, for example ABS has a recorded tensile strength of about 45 MPa and could thus in this case be a suitable thermoplastic, while Polypropylene (PP) has a recorded tensile strength of 37 MPa and would thus not be a suitable material for an embodiment requiring a medium tensile strength (source Substances &amp; Technologies www.substech.com). In some embodiments it can be advantageous to choose a thermoplastic having a high tensile strength (measured by ASTM D 638). By high tensile strength is meant a tensile strength of 60 MPa or more, optionally 80 MPa or more. 
         [0034]    In an embodiment, the load stop  30  is manufactured in a more rigid material than the base portion  10  of the roof box  1 . 
         [0035]      FIG. 3  shows the front end  5  of the roof box  1  in greater detail. The load stop  30  is transparently illustrated for the purpose of clarity. The floor portion  31  of the load stop  30  is positioned adjacent the base portion  10  of the roof box  1 . It is further positioned on the load receiving area  20  at the front end  5  of the roof box  1 . The load stop  30  can be attached in a number of different ways to the base portion  10  of the roof box  1 ; screws, bolts, rivets, welding or adhesive for example. It has however been found that adhesive is advantageous as it does not cause the structure of the load stop  30  or the base portion  10  of the roof box  1  to be weakened, adjusted or changed in any significant way. Suitable adhesives are pressure sensitive adhesives, contact adhesives, hot adhesive or hot melt adhesives, reactive adhesives such as one part, two parts or the like, synthetic adhesives or the like, or mixtures thereof. Preferred adhesives are Cyanoacrylate, Polyurethane, Epoxy and/or Acrylic adhesive. 
         [0036]    The load stop  30  can be adhered to the base portion  10  of the roof box  1  using intermittent adhesive areas  50 , optionally in regular or irregular patterns.  FIG. 3  shows how the load stop  30  has been attached to the load receiving area using a regular intermittent adhesive pattern. The load stop  30  can also be attached to the periphery wall  13  of the base portion  10  of the roof box  1 . In  FIG. 3 , an adhesive pattern  51  is shown attaching the load stop  30  to the periphery wall  13  of the base portion  10  of the roof box  1 . Optionally the load stop  30  is attached to at least a first and a second section of the periphery wall  13  of the base portion  10  of the roof box  1 . The load stop  30  can thus be attached to the base portion  10  of the roof box  1  at both the periphery wall  13  and the load receiving area  20  of the base portion  10  of the roof box  1 .