Abstract:
A roof bar for a motor vehicle, includes a support structure for a roof bar element with an fastening claw which engages at a first end on a side wall rail of a vehicle body and is connected in an articulated fashion to a clamping lever. The fastening claw is guided in a guide in the support structure and a leaf spring is provided which, on one side, engages on the clamping lever-in the region of its free end and, on the other side, is supported on the support structure, wherein when the clamping lever is pressed down towards the attachment claw the-fastening claw is clamped on the side wall rail by the spring force.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is the U.S. National Stage of International Application No. PCT/EP2013/003882, filed Dec. 20, 2013, which designated the United States and has been published as International Publication No. WO 2014/108161 and which claims the priority of German Patent Application, Serial No. 10 2013 000 460.8, filed Jan. 14, 2013, pursuant to 35 U.S.C. 119(a)-(d). 
     BACKGROUND OF THE INVENTION 
     The invention relates to a roof bar for a motor vehicle. 
     Roof bars for vehicles of the generic type are known in numerous variations. They are used for transporting loads on the vehicle roof and are designed as so-called clamping carriers. Usually, two clamping carriers are provided on the vehicle roof, one facing the vehicle front and one facing the vehicle rear, and which may also be referred to as carrier bridge. The roof bars are secured by special clamping carrier feet or clamping claws, which can be clamped to the vehicle&#39;s side-panel frame. Many different constructions are used as clamping mechanisms. Well-known mechanisms which are tensioned via levers or eccentrics have the disadvantage that they do not provide tolerance compensation in the case of rigid levers and an additional component is required to establish clamping tension. 
     From DE 33 40 137 A1, a clampable luggage rack is known, which includes a support structure for a roof bar in the form of a support leg and is secured by a clamp to a roof drip molding of the vehicle roof. The clamp is pivotally connected to a pivot arm via a pivot bolt, which pivot arm is itself pivotally connected to the support leg via a bearing pin. Additionally, a two-armed lever is provided to be able to remove and secure the swivel arm in the manner of a push button. Tolerances of the sidewall rail are not compensated. 
     From CH 318683 a ski rack is known which has a tensioning-lever lock, for fastening to a roof drip molding on the vehicle roof, which tensioning-lever lock has a spring clip made of wire for effecting the tensioning. 
     The object of the invention is to provide a roof bar for a motor vehicle, which is simple in construction and easily operated by hand, wherein a good fastening to the sidewall rail of the vehicle is ensured. 
     SUMMARY OF THE INVENTION 
     According to the invention, this object is achieved by providing a roof bar for a motor vehicle having the features of the independent claim. Advantageous embodiments and refinements of the invention are set forth in the dependent claims. 
     Embodiments of the roof bar according to the invention include a new clamping and tensioning mechanism which advantageously enables a tolerance compensation of the sidewall rail&#39;s geometry so that the clamping tension can be maintained approximately constant over an entire tolerance range. 
     Embodiments of the present invention provide a roof bar for a motor vehicle, which includes a support structure for a roof bar element, including a fastening claw which, on a first end, engages on the sidewall rail of the vehicle body and is pivotally connected to a clamping lever. According to the invention, in the region of its second end the fastening claw is guided in the support structure in a guide and a leaf spring is provided, which on one side engages on the clamping lever in the region of the free end of the clamping lever and on the other side is supported on the support structure, wherein pushing down of the clamping lever towards the fastening claw causes clamping of the fastening claw to the sidewall rail as a result of the spring force. 
     The movable arrangement of the fastening claw in its guide of the support structure together with the leaf spring, creates a compensatory component, which enables compensating tolerances of the sidewall rail&#39;s geometry so that the final clamping tension can be maintained almost constant over an entire tolerance range. Moreover, the operating forces for pushing down the clamping lever can be reduced so as to enable an easy one-hand-operation. 
     In an advantageous embodiment of the roof bar, bearing brackets are provided on the clamping lever and on the fastening claw for pivotal connection between fastening claw and clamping lever, which bearing brackets receive a shaft which is movably received on the guide in the support structure. With this, a connection between both components as well as a connection to the support structure is achieved in a simple manner. 
     In a further advantageous embodiment of the roof bar, the fastening claw is guided at its second end in the support structure in a second guide. This allows an additional connection of the fastening claw to the support structure which results in a particularly safe and durable clamping. 
     In a further advantageous embodiment of the roof bar, the two guides are designed in a simple manner as longitudinal slots in opposing legs of the support structure. 
     In a further advantageous embodiment of the roof bar, a particularly simple support results when the second end of the fastening claw has pins which are received in the longitudinal slots of the second guide. 
     In a further advantageous embodiment of the roof bar, a reliable and simple connection of the leaf spring to the clamping lever results by providing a clamping lever shaft which is received in bearing brackets on the clamping lever. 
     In a further advantageous embodiment of the roof bar, a simple and reliable connection of the leaf spring to the support structure results by providing a spring shaft between the legs of the support structure. 
     In a further advantageous embodiment of the roof bar, the fastening claw has an opening for receiving the shaft of the clamping lever in its depressed state. With this, a durable, reliable closing of the clamping lever is ensured in a simple manner without further need of supplementary components. 
     In a further advantageous embodiment of the roof bar a good power transmission from the roof bar element to the vehicle roof results, when the support structure has two profile elements in U-shape that are connected to each other. It is hereby advantageous to provide the support structure with a base component that rests against the vehicle roof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Advantageous embodiments of the invention are illustrated in the drawing and are described below. It is shown in: 
         FIG. 1  a schematic perspective view of an exemplary embodiment of a roof bar for a motor vehicle according to the invention in closed position which is attached to a vehicle roof, 
         FIG. 2  a perspective view of the roof bar of in  FIG. 1  without vehicle roof in a semi-closed position, 
         FIG. 3  a perspective view of the roof bar of in  FIG. 1  without vehicle roof in an open position, 
         FIG. 4  a perspective view of the roof bar of in  FIG. 1  without vehicle roof in a closed position. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a roof bar  1  for a vehicle in the closed position, which is mounted on a vehicle roof  2  and is provided in a known manner for receiving loads or luggage, such as skis or the like. For this, usually two roof bars  1 , one facing the vehicle front and one facing the vehicle rear, are fastened to the vehicle roof  2 . 
     Each roof bar  1  has a roof bar element  5 , which extends over the vehicle roof in transverse direction y and which is only partially shown in  FIGS. 1 to 4  and in the exemplary embodiment is formed as a hollow section. The roof bar element  5  is attached to the vehicle roof  2  on a sidewall rail  10  or on a side panel frame of a vehicle body  3  via two opposing support structures  7 . For this purpose, the support structures  7  respectively have a first outer U-shaped profile element  15 , which has two legs  16 , each with a support leg  17  and a connecting element  18 . The U-shape of the first profile element  15  is formed by the two legs  16  and the connecting element  18  which connects the two legs  16  and extends parallel to the vehicle roof  2 . The outer profile element  15  is respectively supported with one support leg on a rectangular-shaped base element  20 , which rests on the vehicle roof  2 . Within the first profile element  15  a second profile element  25  is provided which is also U-shaped. The U-shape of the second profile element  25  is formed by two legs  26  and a second connecting element  27  that connects the two legs  26  and extends parallel to the vehicle roof  2 . The two legs  26  project from the base element  20 . A connection between both profile elements  15 ,  25  can be achieved via the two connecting elements  18 ,  27  that are situated above each other. Preferably the first profile element  15  and the second profile element  25  are made of sheet metal. The roof bar element  5  is supported on the first connecting element  17  of the first profile element  15  and thus transmits the weight received on the roof bar element via the support legs  17  and the base element  20  to the vehicle roof  2 . The support structure  7  shown in the exemplary embodiment is formed by the first profile element  15 , the second profile element  25  and the base element  20 . 
     A fastening claw  30  is pivotally connected with the support structure  7  or the second profile element  25 . This fastening claw  30  engages with its first end  31  on the sidewall rail  10  or the side penal frame, for which purpose an angled portion  32  is constructed on the fastening claw  30 . As shown in  FIG. 1 , the angled portion  32  engages directly on the sidewall rail  10  or on the side panel frame. However, it is also possible for the angled portion  32  to engage on a roof drip molding on the sidewall rail  10 . 
     In order to better illustrate the roof bar  1 , the roof bar  1  is shown without the first profile element  15  in  FIGS. 2 to 4 . 
     In contrast to  FIG. 1 ,  FIG. 2  shows the roof bar  1  in a semi-closed position. As shown in  FIG. 2 , two bearing eyes or bearing brackets  34  are laterally provided in the region of the second end  33  of the fastening claw  30 , for forming a first bearing section  35  with the second profile element  25 , which bearing eyes or bearing brackets  34  for example abut with a clearance on the inside of the legs  26  of the second profile element  25  and together rotatably receive a shaft  40 . With its shaft ends  41  the shaft  40  is received in first guides  50 , which are provided in the legs  26  of the second profile element  25 . With this the shaft  40  is received by the profile element  25  so as to be shiftable toward both sides. The first guides are preferably constructed as longitudinal slots  41  and have guideways for the fastening claw  30  and extend obliquely slanted relative to the vehicle&#39;s vertical direction z toward the vehicle interior and are provided in a front vehicle-external region of the legs  26 . Additionally, the second end  33  of the fastening claw  30  is laterally provided with two pins  37  that engage in a second guide  55  of the support structure  7  or in the legs  26  of the second profile element  25 . The second end  33  of the fastening claw  30  is received in the second guide  55  so as to be slidable towards both sides. For this purpose, the second guides  55  are preferably constructed as longitudinal slots  56  and form guideways for the pins  37 . The longitudinal slots  56  extend obliquely slanted relative to the vehicle&#39;s vertical direction z toward the vehicle interior and are, in contrast to the first guides  50 , provided in a rear area of the legs  26  of the second profile element  25  that is closer to a vehicle interior. The second longitudinal slot  56  has a greater longitudinal extent than the first longitudinal slot  51  and may have a bending or slight bend and a small width or can be constructed to be more narrow. Hence, the second end  33  of the fastening claw  30  forms, together with the second guide  55  a second bearing section  37  for the fastening claw  30  on the support structure  5 . 
     Also connected to the shaft  40  is a clamping lever  60 , which has two clamping lever bearing eyes or two first clamping lever bearing brackets  61  at its second end  63  situated within the legs  26 . The clamping lever  60  is pivotally connected to the fastening claw  30  via the shaft  40 . The first clamping lever bearing brackets  61  extend on the inside at a short distance to the bearing brackets  34  of the fastening claw  30 . At free first ends  62  of the clamping lever  60 , two second clamping lever bearing brackets  64  are provided, which support a clamping lever shaft  65 . The clamping lever shaft  65  serves for receiving a first leaf spring end  71  of a spring element in form of a leaf spring  70 . Reception of the first leaf spring end  71  can be accomplished through a angled shape of the leaf spring end  71 , which for example may be introduced in a slot which is introduced in the clamping lever shaft  65 . The leaf spring  70  is supported with its other second leaf spring end  72  on the support structure  7  or on the legs  26  of the second profile element  24 , for which a spring shaft  66  is provided between the legs  26 . The spring shaft  66  serves for receiving the second leaf spring end  71  of the leaf spring  70 . This may occur, analogous to the first leaf spring end  71 , through a bended shaping of the second leaf spring end  72 , which may, for instance, be introduced in a slot in the leaf spring  66 . Approximately in its center the fastening claw  30  has a rectangular opening  38 . The opening  38  serves for receiving the first leaf spring end  71  with the clamping lever shaft  65 , which in the closed position of the roof bar, enters into the opening with the first clamping lever bearing brackets  61 , as is shown in  FIGS. 1 and 4 . 
     In contrast to  FIGS. 1 and 2 ,  FIG. 3  shows an open position of the roof bar  1 , wherein the clamping lever  60  is maximally opened and the leaf spring  70  is relaxed. In this position, the common shaft  40  of the fastening claw  30  and clamping lever  60  is situated within the first guide  50  at the lower ends which are closer to the vehicle roof  2 . Similarly, the two pins  37  are situated at the second end  33  of the fastening claw  30  in the second guide  55  or the second longitudinal slots  56  in a lower position close to the vehicle roof  2 . 
       FIG. 4  shows a roof bar  1  in a closed position, wherein the clamping lever  60  is closed and together with the fastening claw  30  and the second clamping lever bearing brackets  6  enters into the opening  38  of the fastening claw  30 , snaps with the second clamping lever bearing brackets  64  where it quasi engages behind. In the shown closed state, the lever mechanism is positioned in an over-centre position. This means that a point of maximum clamping force of the leaf spring  70  was overcome during the closing motion and that the leaf spring  70  acts on the fastening claw  30  with a predeterminable clamping force or clamping tension clamping force. The common shaft  40  of the fastening claw  30  and the clamping lever  60  has reached an upper region in the first guide  50  that is closer to the roof bar  5 . Similarly, both pins  37  on the second end  33  of the fastening claw  30  have reached the second guide  55  or the two longitudinal slots  56  in a upper position that is closer to the roof bar  5 . 
     According to the invention, the leaf spring  70  forms a further clamping lever for the fastening claw  30  and is able to generate the clamping force required for the attachment of the roof bar  1  to the sidewall rail  10  in the manner of a knee lever. At the same time, tolerances of the sidewall rail  10  can be balanced autonomously so that a constant level of clamping force is provided. The leaf spring  70  is thus incorporated into the clamping mechanism as a component that enables to maintain the clamping force constant over the entire tolerance range. Due to a thoughtful geometric arrangement of clamping lever  60  and leaf spring  70  and due to the arrangement of the fastening claw  30  for rotation and movement in vertical axis  7  of the vehicle in both guides  50 ,  55  of the support structure  7 , a compensating element is provided that enables reducing the operating forces required for depression of the clamping lever  60  so that an easy single-hand operation is possible. The clamping mechanism according to the invention is achieved by two levers, the clamping lever  60  and the leaf spring  70 , wherein a sliding in the guideways  50 ,  55  is possible so that a clamping of the fastening claw  30  on the sidewall rail  10  is achieved. Because the second lever represents the leaf spring  70 , a tolerance compensation of the side wall rail  10  is achieved. 
     For attachment to the vehicle roof  2 , the mechanism has to be moved from the open position as shown in  FIG. 3  to the closed position shown in  FIG. 4 . For this the rigid clamping lever  60  is depressed until the fastening claw  30  abuts the side penal frame. Then a form fit or clamping occurs due to the shape tension and spring tension of the leaf spring  70 . Due to geometry and construction of this leaf spring  70 , which is adjusted to the tolerance of the side panel frame, a constant clamping force is ensured. Due to the geometry of lever and spring as well as the positioning of the guideways,  50 ,  55 , forces and movement of the fastening claw  30  are adjusted so that a simple single-handed operation is ensured. An additional locking device becomes obsolete. In closed position as shown in  FIG. 4 , the lever mechanism is located in an over-centre position so that a further securing element is not necessary.