Patent Publication Number: US-2009217491-A1

Title: Attachment means and a method for fastening vehicle panels using said attachment means

Description:
BACKGROUND AND SUMMARY 
     The present invention relates to an attachment means intended for fastening vehicle panels and a method for attaching panels using said attachment means. The attachment means may be used for either exterior and interior panels made from metal, plastic or any other suitable material. 
     A vehicle frame or structure is often covered by an outer panel to give an outer or inner surface of the vehicle a desired functional or aesthetic design, shape or colour. Panels of this type may be used to cover or protect various mechanical or electronic equipment, or simply to cover structural components or beams that need not be accessed by a user after assembly of the vehicle. At the same time, it is often desirable to make such panels removable to allow access for service or replacement of a damaged panel. 
     A known method of attaching panels onto an exterior or interior surface of a vehicle is to attach weld screws or threaded nuts onto a supporting structure. The panel is then positioned on the vehicle so that recesses in the panel coincide with the weld screws, whereby the panel is screwed into place. A problem relating to this method is that the supporting structure may be damaged during attachment of the weld screws, primarily caused by the localized heating of the material adjacent the relatively small weld screw. This may be a particular problem if the supporting structure comprises a relatively thin sheet metal. The welding process may also cause damage or discoloration on the rear surface of the supporting structure, requiring additional painting or covering of this surface. A further problem occurs if the panel is to be mounted in a narrow space or behind equipment such as a handrail or similar. It may then be necessary to bend or deform the panel locally in order to position some recesses over their corresponding weld screw. This makes the assembly of the panel more complicated and time consuming and may cause injury to the person carrying out the assembly. Also, bending of the panel may cause permanent deformation or cracks in parts of the panel. 
     Another method of attaching panels is to provide either the panel or the supporting structure with recesses, which recesses cooperate with snap-on clips on the supporting structure or the panel, respectively. One example of such clips is known from EP 1 292 486. A problem with this method is that if one of said clips breaks during assembly of the panel, the entire panel may have to be removed in order to replace the clip. Also, when removing the panel, during assembly or at a later date, clips of this type are prone to breaking, requiring replacement of multiple clips. A further problem is that snap-on clips may not fix the panel sufficiently to the supporting structure, resulting in rattling a noise as the vehicle moves over uneven ground. 
     An aspect of the invention aims to solve these problems by providing an improved fastening element that allows a panel to be attached and removed without the use of fixing means that may damage the attachment means, the panel or the supporting structure. The attachment means will also facilitate mounting of panels on the supporting structure in a confined space. 
     According to a preferred embodiment, an aspect of the invention relates to an attachment means for attaching a panel to a supporting structure on a vehicle. The attachment means may comprise a profile with a first section extending substantially outwards from the supporting structure and a second section extending in a plane substantially parallel to the supporting structure. The second section may be arranged to extend into a recess in an outer edge along one side of the panel, in order to locate and fix one end of the panel in at least one direction. The side edge of the panel is preferably, but not necessarily located in a substantially vertical plane. However, the position of the side edge may vary depending on where the panel is to be mounted, or on the location of the supporting structure onto which the attachment means are fixed. 
     According to one embodiment, the profile may comprise a third section which extends parallel to and is attached to the supporting structure. An attachment means of this type may have a substantially U- or J-shaped cross-section. The relative dimensions of the first section are dependent on a number of factors, such as the weight or thickness of the panel and/or the desired distance between the supporting structure and the inner surface of the panel. The relative dimensions of the second and third sections depend on factors such as the size and weight of the panel, the depth of the recess in the panel, etc. 
     The attachment means may be permanently attached to the support structure by welding. Alternatively, the attachment means may be attached to the support structure by mechanical fastening means or by means of a suitable adhesive. The type or means used for attaching the profile may be dependent on the size and/or weight of the panel, the type of vehicle and the area of use of the vehicle. For instance, a relatively heavy panel attached to a work vehicle may be subjected to relatively large forces and/or vibrations, requiring the attachment means to be permanently welded to a load bearing structural part or closed profile beam in the vehicle. According to a preferred embodiment, plug welding may be used in order to prevent the thickness of the weld from exceeding the thickness off the third section in contact with the support structure. This solution may be used in locations where the supporting structure may comprise a closed profile. In may preferably be used for mounting panels on vehicles manufactured in relatively small series, as attaching the profile can be a relatively labour intensive process. 
     According to one embodiment, the first and second sections of the attachment means forms an integral, pressed part of the support structure section. This solution may be used in locations where the supporting structure does not comprise a closed profile. In may preferably be used for mounting smaller and/or lighter panels on vehicles manufactured in relatively large series, as the pressing step may suitably be performed when manufacturing of the supporting structure. 
     The above embodiments allows for panels to be mounted in confined spaces, where standard attachment means are difficult to fit or access, such as behind handrails or in or near internal corners. 
     According to one embodiment, the second section may comprise a free end that is at least partially enclosed by a resilient material, which material is arranged to be located between the second section and the recess. The free end may be a straight edge wherein a substantially U-shaped resilient component encloses the free end on three sides. The resilient component may be extruded to give a suitable profile and may preferably, but not necessarily, be cut to a length longer than the width of the free end of the second section, but not exceeding the width of the recess. 
     According to an alternative embodiment, the second section comprises a free end enclosed by a bushing of a resilient material, which bushing has recess is arranged to correspond to the shape of the free end. Here, the shape of the free is preferably, but not necessarily a straight edge. The resilient component may be injection moulded to give a suitable shape and/or profile. The resilient component may preferably, but not necessarily, be dimensioned so that the recess corresponds to the shape the free end of the second profile, and that its outer dimensions substantially corresponds to the shape of the recess in the edge of the panel. 
     According to an alternative embodiment, the enclosing resilient material or components described above may be provided with extruded or injection moulded ribs and/or projections on at least a pair of opposing major outer surfaces, which ribs, projections or a combination thereof are arranged to be at least partially deformed upon contact with the recess. For instance, the resilient component may be provided with a series of parallel ribs extending at right angles to the direction in which the free end enters the recess in the panel. The ribs may have a triangular, square or semi-circular cross-section. This may allow the panel to be press fitted onto the second section of the attachment means, under simultaneous deformation of the ribs. This causes the panel to be exactly located onto the attachment means, while preventing chafing or scratching of the panel during the mounting process. The ribs will also reduce the surface friction between the profile and recess during mounting of the panel. In addition, the resilient component will absorb vibration and prevent rattling from occurring when the vehicle is in use. 
     A non-limiting example of a suitable resilient material is Ethylene Propylene Diene Monomer, or EPDM. This material will retain good shape stability in temperatures up to about +85° C., and will retain its elasticity in temperatures below about −40° C. 
     An aspect of the invention relates to a method for attaching a panel to a supporting structure on a vehicle, using at least one attachment means according to the invention. The method may comprise the steps of: 
     attaching the attachment means onto a first section of the supporting structure,—positioning the panel relative to the supporting structure, wherein an edge at a first end of the panel comprising at least one recess is located adjacent said attachment means, 
     displacing the panel towards the attachment means, whereby each recess in an outer edge of the panel mates with a free end of a corresponding attachment means, and 
     attaching at least a second, opposite end of the panel to a second section of the supporting structure. 
     A relatively exact location of the panel can also be achieved either by using separate attachment means at a second end of the panel. Alternatively it is possible to use a suitable section of the profile as a reference point and/or a combination of the separate attachment means and the profile. Attaching at least a second, opposite end of the panel may be performed by screwing or otherwise suitable fastening means. In this way, the second, opposite end of the panel may be attached to the second and/or other section of the supporting structure, which section is arranged at a location removed from the first section of the supporting structure. 
     When performing the method, it may comprise the further step of mounting a bushing of a resilient material on the free end of each attachment means prior to positioning of the panel. Alternatively, the bushing of a resilient material may be mounted in each recess prior to positioning of the panel. In the latter case, the opening around the recess for the free end of the second section may be rounded or bevelled to facilitate mounting. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In the following text, the invention will be described in detail with reference to the attached drawings. These schematic drawings are used for illustration only and do not in any way limit the scope of the invention. In the drawings: 
         FIG. 1  shows an exploded view of an attachment means according to one embodiment of the invention; 
         FIG. 2  shows a section of a panel mounted onto the attachment means of  FIG. 1 ; 
         FIG. 3  shows a cross-section of the attachment means of  FIG. 2 ; 
         FIG. 4  shows an exploded view of an attachment means according to one embodiment of the invention; 
         FIG. 5  shows a section of a panel mounted onto the attachment means of  FIG. 4 ; and 
         FIG. 6  shows a cross-section of the attachment means of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION  
       FIG. 1  shows an exploded view of an attachment means according to a first embodiment of the invention, comprising a substantially J-shaped profile P with a first section  1  extending outwards from a schematically indicated supporting structure S, a second section  2  extending in a plane substantially parallel to the supporting structure S, and a third section  3  extending in a plane parallel to and attached to the supporting structure S. The supporting structure is schematically indicated as a profile comprising a closed section. The second section  2  is arranged to extend into a recess  4  in an outer edge  5  along one side of a panel  6 , in order to locate and fix one end of the panel  6  relative to the supporting structure S. The second section has a free end extending towards the recess  4 , which free end is provided with a substantially U-shaped component  7  made from a resilient material that encloses the free end on three sides. The U-shaped component  7  is arranged to be located between the second section  2  and the recess  4 . In the shown example, the free end facing the recess  4  has a straight edge wherein the U-shaped component  7  used is an extruded profile made from EPDM. The component  7  has been cut to a length equal to the width of the recess, which is larger than the width of the free end of the second section  2 . The U- shaped component  7  has a pair of major outer surfaces  8 ,  8 ′, which will extend substantially parallel to the supporting structure S when the component  7  is mounted on the profile P. The outer surfaces  8 ,  8 ′ are provided with integral extruded triangular ribs which will be resiliently deformed when in contact with opposing inner walls of the recess  4 . The ribs on each side of the component  7  have an angled front surface facing the recess  4  in the panel  6 , and a rear surface perpendicular to the direction in which the panel is mounted onto the profile. The ribs will reduce the surface friction between the profile and recess during mounting of the panel. 
       FIG. 2  shows a section of a panel  6  mounted onto a profile P according to the invention. As can be seen from the figure, the attachment means is almost completely hidden from view by the panel. Apart from reducing the number of operations to be carried out during assembly of the panel  6 , the solution allows for a simplified assembly in a confined space, e.g. behind hand rail or other structures, or in internal corners. 
       FIG. 3  shows a cross-section of a panel mounted onto the attachment means of  FIG. 2 . The Figure shows the J-shaped profile P attached to the supporting structure S by means of a plug weld  10  in an opening  11  through the third section  3  of the profile. The panel  6  has been mounted on the second section  2  of the profile, wherein the recess  4  has been pressed onto the free end of the second section  2  with its U-shaped resilient component  7 . 
       FIG. 4  shows an exploded view of an attachment means according to a second embodiment of the invention, comprising a substantially J-shaped profile P with a first section  1  extending outwards from a schematically indicated supporting structure S, a second section  2  extending in a plane substantially parallel to the supporting structure S, and a third section  3  extending in a plane parallel to and attached to the supporting structure S. The attachment means in  FIG. 4  differs from the embodiment of  FIG. 3  in that the second section has a free end extending towards the recess  4 , which free end is provided with a bushing  12  made from a resilient material that encloses the free end on all sides. The resilient bushing  12  is arranged to be located between the second section  2  and the recess  4 . In the shown example, the free end facing the recess  4  has a straight edge wherein the bushing  12  has been provided with a recess  13  with an internal shape conforming to the shape of said free edge. The resilient bushing  12  used is an injection-moulded profile made from EPDM. 
       FIG. 5  shows a section of a panel mounted onto the attachment means of  FIG. 4 . As described above, the attachment means is almost completely hidden from view by the panel. In addition, as the bushing  12  encloses the free end of the second section  2  on all four sides, the panel  6  can be located with relatively high accuracy with respect to the profile P. Location of the panel  6  in the direction of mounting is achieved by a separate attachment means on an opposite edge of the panel (not shown). Location of the panel can also be achieved using a suitable section of the profile as a reference point and/or a combination of the separate attachment means and the profile. The bushing  12  will also be able to absorb vibrations in multiple directions. 
       FIG. 6  shows a cross-section of the attachment means of  FIG. 5 . The Figure shows the J-shaped profile P attached to the supporting structure S by means of a plug weld  10  in an opening  11  through the third section  3  of the profile. The panel  6  has been mounted on the second section  2  of the profile, wherein the recess  4  has been pressed onto the free end of the second section  2  with its injection moulded component  12 . Although not shown here, the component  12  may be provided with ribs or projections in the same way as described in connection with  FIGS. 2 and 3  above. 
     The invention is not limited to the above embodiments, but may be varied freely within the scope of the claims.