The subject invention concerns a clamping device for roof-mounted load carriers for vehicles the roof structure of which comprises an upwardly projecting sheet metal flange extending in the lengthwise direction of the vehicle and designed to be gripped by a foot member arranged on the load carrier. In many modern cars this sheet metal flange or ridge is positioned in a depression formed in the vehicle roof and it is often covered when the load carrier is not mounted on the car. This arrangement is often necessitated for aerodynamic reasons, since it is desired that the vehicle body be as smooth as possible and as free as possible from projecting parts. The main purpose of the subject invention is to provide a clamping device by means of which the load carrier may be firmly mounted on vehicles, also of the type that are provided with sheet metal flanges or ridges of the kind mentioned above. In fastening devices for this purpose the clamping effect from the parts abutting against the sheet metal flange must be extremely high in order to retain the load carrier in position. The subject invention provides a clamping device of the kind mentioned above by means of which extremely reliable securement is obtained also when the sheet metal flanges are comparatively weak. The foot member in accord¬ ance with the invention has its lower part designed in a manner similar to that of a pair of pincers and includes jaws arranged for engaging the sheet metal flange on either side thereof, a hinge disposed closely above the sheet metal flange, and pincer arms above said hinge at least one of which arms is arranged for pivotal movement together with its corresponding jaw about said hinge, said foot member also including a pincer arm actuating mecanism arranged, by acting on the pincer arms, to bring about

mutual pivotal movement of said arms, thus forcing the jaws to either close on said sheet metal flange or to disengage said flange.

Preferably, the distance from the hinge to the point of engagement of said jaws is considerably smaller, pre¬ ferably many times smaller, than the distance from the hinge to the point of attack of said actuating mecanism on said pincer arms. Owing to this arrangement the force transmission ratio becomes sufficiently high to ensure that the clamping force exerted on the sheet metal flange is very high in relation to the load on the actuating mechanism.

Preferably, the actuating mecanism comprises a pressure-exerting member which is movable along a circular path and the corresponding pincer arm is formed with a track along which said pressure-exerting member moves such that the movements of said pincer are caused by said member owing to an eccentric motion of the latter. In this manner comparatively simple means are provided for the actuation of the pincer arms.

Also preferably, the track formed in the pincer arm comprises a pointed section the apex of which is directed towards the shaft about which the pressure-exerting member turns, and the pressure-exerting member is arranged to move between a position to one side of the pointed section for release of the arm and an over-center clamping position on the opposite side of said pointed section. The over-center effect thus obtained ensures that the clamping device will not be unintentionally released. Furthermore, means are preferably provided for setting the distance between the pressure-exerting member and the center about which said member turns. Owing to this arrangement the clamping force of the jaws may be easily adjusted to the corresponding vehicle, also upon variations of the thickness of the securement flange.

Preferably, the pressure-exerting means is arranged on a manually pivotable actuating arm the center of pivotment of which likewise forms the center about which the pressure-exerting member turns. Further, the pressure- exerting member preferably is arranged on a lever mounted on the actuating arm the angular position of which is adjustable and determines the eccenter position of the pressure-exerting member. Owing to this arrangement a very simple setting device is obtained for regulation of the clamping effect of the device. Preferably, the lever supporting the pressure-exerting member is a two-armed lever and is journalled to the actuating arm at its one end and is adjustably attached thereto at its opposite end, supporting the pressure-exerting member therebetween. In addition, the pressure-exerting member is con¬ figured as a yoke comprising two pressure points, one on either side of its point of attachment to the actuating arm. In order to facilitate the movement of the pressure- exerting member along the track on the pincer arm said member is formed as a roller body.

One embodiment of the clamping device in accordance with the invention will be described in the following in closer detail with reference to the accompanying drawing figures, in which: Fig. 1 illustrates a foot member mounted on a load- carrier of the kind concerned,

Fig. 2 is a sectional view through the portion of the vehicle roof formed with a sheet metal flange to which the foot member is intended to be secured, Fig. 3 is a sectional view through that foot member when clamped in position,

Fig. 4 is a view corresponding to Fig. 3 and illustrates the same foot member in its un-clamped posi¬ tion, Fig. 5 is a view similar to Fig. 4 showing the foot member in its position ready to be lifted off the sheet metal flange formed in the vehicle roof,

Fig. 6 is a view of the foot member as seen from the left in accordance with Fig. 4,

Fig. 7 is a view similar to Fig. 6 of the same foot member, certain components of the clamping device having being removed, and

Fig. 8 is a view of the foot member as seen from the left in accordance with Fig. 1.

The drawing figures illustrate one end portion of the load carrier extending across a vehicle roof and con- sisting of a carrier rail 2 extending across the vehicle roof 1, and a foot member 3 arranged to securely grip a sheet metal flange 4 formed in the vehicle roof. In accordance with the example illustrated the sheet metal flange 4 is formed in a retracted position in a depression 5 in the vehicle roof. When the load carrier is not in use the depression 5 normally is covered by cover strips or similar means not illustrated in the drawing figures. Such strips are essential in order to give the vehicle maximum surface smoothness and consequently a favourable flow- condition configuration. It should be understood that this arrangement naturally does not exclude the possibility of using the load-carrier in accordance with the invention for attachment also to sheet-metal flanges of the kind projecting above the vehicle roof. Numeral reference 6 designates a fastening bracket in the shape of a box which is open towards the left as seen in Figs. 1-5, the upwardly directed lateral wall 6' of which rests against the lower face of the carrier rail 2. The fastening bracket 6 is clamped against the carrier rail 2 by means of a clamping piece 7 arranged in the interior of the tubular carrier rail, said clamping piece 7 being secured at its one end by means of a rivet 8 or similar means, said rivet extending through the lateral wall 6' by means of which the fastening bracket supports the carrier rail 2, through a lengthwise slit in the lower wall 2' of the carrier rail and through the clamping piece 7. In addition, the clamping piece 7 is secured by means

of a fastening screw 9 screwed into the clamping piece from below. The clamping piece 7 is elongate and at its end cooperating with the rivet 8 it is slightly bent, which means that a certain eccenter effect, and con- sequently a clamping effect, is obtained when the fastening screw 9 is tightened. One of the arms 12 of an attachment means similar to a pair of pincers is secured in the box-like fastening bracket by means of securement means 10 och 11, which means, in accordance with the embodiment shown, are in the form of rivets, the pincer-like attachment device also having a second pincer arm 13. The first pincer arm 12 is associated with a jaw 14 and the second arm 13 is associated at its lower end with a corresponding jaw 15. The pincer arm 13 together with its associated jaw 15 is pivotable about a hinge 16. The faces of the two jaws that are turned towards the sheet metal flange 4 preferably are coated with a pro¬ tective layer to avoid scratches and damages on the paint of the sheet metal flange. The distance a between the hinge 6 and the point in which the jaws 14, 15 exert their clamping action against the sheet metal flange preferably is as small as possible whereas the pincer arms 12, 13 are comparatively long. Numeral reference 17 designates generally an actuating mechanism which is pivotable about a pivot pin 18 mounted in the end portions upended from the securement part of the arm 12. The actuating mechanism is formed with a pressure exerting member 20 which is arranged to move in a circular part 21 about the pin 18. The pressure-exerting member is arranged to cooperate with the track 22 formed on the arm 13. The track 22 is formed with a pointed section 22' . From the pointed section 22' the track changes into an outwardly directed end portion 22" which is positioned below the pressure-exerting member when the actuating mechanism is pivoted to the upper posi- tion illustrated in Fig. 4. In accordance with the embodi¬ ment illustrated the distance b between the hinge 16 and the pointed section 21' is many times larger than the

distance a, with the result that the clamping force exert¬ ed against the sheet metal flange becomes quite con¬ siderable, also when the force on the actuating mechanism

17 is comparatively moderate. Numeral reference 23 designates a spring which in accordance with the embodi¬ ment illustrated is configured as a hair pin spring embracing the hinge 16 and having its one leg in abutment against the arm 13 whereas its opposite leg abuts against the other arm 12 and tends to move the two arms apart, with the result that the jaws tend to close on the sheet metal flange 4. However, the arm 13 is free to be forced, against the action of spring 23, in the direction towards the arm 12 when the pressure-exerting member 20 assumes the position illustrated in Fig. 4, i.e. to the position illustrated in Fig. 5 in which the foot member may be lifted above the angled upper edge of the sheet metal flange.

The actuating mecanism 17 consists of a handle 24 in the form of an arm which is pivotable about pivot 18 between the position illustrated in Fig. 3 and the position illustrated in Fig. 4. To the actuating arm 24 serving as a handle is pivotally mounted one end of a lever 26 for pivotal movement about a pivot pin 25. The lever 26 supports the pressure-exerting member 20 which in accordance with the embodiment illustrated is formed like a roller body forming a yoke-like member extending in two directions from the lever and formed by two roller bodies provided on either side of the lever 26. The relative angular position between the lever 26 and the actuating arm 24 is adjustable by means of a setting screw 27. By regulating this angular position the distance c between the pressure-exerting member 20 and the center of the pin

18 may be adjusted, allowing setting of the radius of the circular path 21 along which the pressure-exerting member 20 moves, and thus setting of the position of mutual angular spacing to which the arms 12 and 13 are moved when the actuating arm 24 is pivoted downwards. Because the

rivets 11 extend through apertures formed in the two parts, the position of which apertures in one part being chosen to a suitable location along a curve 28 having a curvature the radius r of which is centered in the rivet 10, the angular position a of the arm 12 with respect to the fastening bracket 6 may be adjusted to the inclination of the roof of the associated vehicle. Naturally, it is also possible to form the slits 28 in the fastening bracket 6. Numeral reference 29 designates a covering hood covering the movable parts of the clamping device. In accordance with the embodiment illustrated the covering hood may be locked to the rest of the components by means of a key-operated lock 30, the clamping device thus being well protected against unauthorised access which prevents thefts of the load carrier and of any load positioned thereon. In Fig. 6 the acuating arm 24 and the pressure- exerting member are indicated in the positions they assume when active as in Fig. 3 and inactive as in Fig. 4.

By loosening the screw 9 the position of the foot member along the carrier rail 2 may be adjusted and this position may be made fixed by re-tightening of the attachment screw 9. When the arm 13 is pivoted in the direction towards the arm 12 against the action of the spring 23 the foot member may be freely deposited above the sheet metal flange 4 as illustrated in Fig. 5. When the active pressure exerted on the arm 13 ceases the spring 23 returns the latter to the inactive clamping position illustrated in Fig. 4. By pivoting the actuating arm 24 which serves as the handle, the pressure-exerting member 20 is forced to move towards and along the track 22 formed on the arm 13. When the pressure-exerting member 20 has moved past the straight interconnecting line between the pointed section 22' of the track and the pivot pin 18, i.e. when it assumes an over-center position with respect to the raised section 22' of the track, a stable locked position is obtained, and consequently the foot member is securely clamped against the sheet metal flange 4, without

any tendencies to open up from the latter. This position is maintained with additional safety when the covering hood 29 is applied and locked as illustrated in Fig. 3. The invention is not limited to the embodiment described in the aforegoing and illustrated in the drawing figures as an example only but could be varied as to its details within the scope of the appended claims without departing from the inventive idea of the invention. For instance, the design of the foot member as well as of its attachment to the carrier rail 2 may be varied according to wish. For instance, in accordance with a simplified version the actuating mechanism 17 need not be of an adjustable kind. Also the devices for adjustment of the distance of the pressure-exerting member 20 to the pivot pin 18 may be of a different kind than those referred to. For example, the pressure-exerting member could be mounted directly on the actuating arm in a rigid fashion or so as to exhibit a variable distance to the pivot pin 18. Instead of the two arms 12, 13 including their associated jaws 14, 15 being arranged in pairs on either side of the hinge of the actuating arm 24 it is quite possible to reverse these conditions, i.e. to arrange the arms 12, 13 in the center with the actuating arm in a bridging position. Also other modifications that readily come to the expert's mind may fall within the scope of the appended claims without departure from the inventive idea.