A foot for fixing a load-carrying cross-member to a longitudinal rail of a motor-vehicle roof

Abstract: The fixing foot comprises a body (14) fixed to one end of a load-carrying cross-member (10) and shaped for bearing on a longitudinal rail (R) of a motor-vehicle roof. The body (14) contains a nut-and-bolt tensioning device (30) of which the bolt (32) has a head (36) which can be operated from above. The two ends (44) of a substantially inextensible loop (42) are anchored to a slide (38) incorporating a nut (40). The loop (42) is passed under the rail (R) and is hooked onto an engagement member (54) fixed to the slide (38). Rotation of the bolt (32) in one direction tensions the loop (42) by raising both the ends (44) of the loop which are anchored to the slide (38), and the tip (46) of the loop which is hooked onto the engagement member (54). The loop (42) is thus put under tension, fastening the rail (R) between the body (14) and the loop.

Description: The present invention relates to a foot for fixing a load-carrying cross-member to a longitudinal rail of a motor-vehicle roof, according to the preamble to Claim 1. Throughout the present description and in the claims, terms and expressions indicating positions and orientations are intended to refer to the installed condition on a motor vehicle. Thus, the expression "inner side" indicates a side facing towards the centre of the vehicle roof and the expression "outer side" indicates a side facing towards the lateral edge of the roof. The term "load-carrying cross member" is intended to define a cross-member of any device intended for transporting objects on a motor-vehicle roof such as, for example, a roof-rack bar, a ski rack, a boat rack, or a bicycle rack. A fixing foot according to the preamble to Claim 1 is known from the document DE-U-82 29 446, according to which the two ends of the loop are anchored to the nut portion and the member for the engagement of the tip of the loop is fixed to and forms part of the body of the foot. A very similar fixing foot, in which the member for the engagement of the tip of the loop is formed on the nut portion and the two ends of the loop are anchored in a fixed position on the body of the foot is known from the document DE-U-84 04 525. In both of these known devices, the portions of the loop between the anchorage ends and the tip of the loop extend along paths arranged substantially at an obtuse angle, the region corresponding to the vertex of which is situated beneath the rail. With this arrangement, the rail is gripped between the loop and a pad by which the foot bears on the rail by a substantially vertical component of a force which, in order to be of sufficient magnitude, subjects the cable constituting the loop to a tensile stress which may be excessive. The cables used comprise a core constituted by a thin steel wire rope and a sheath of PVC or other plastics material. An excessive tensile stress may fatigue the core by reducing the twist of the wires or by stretching. In order to reduce the tensile stress, it would be necessary to move both the anchorage point of the two ends of the loop and the engagement member closer to the rail so that the two portions of the loop would at least form an acute angle or, preferably, would be parallel to one another. Although this hypothetical arrangement would be advantageous with regard to the tensile stress to which the cable of the loop would be subjected, it would result in an increase in the height of the foot which, from the aerodynamic point of view, could lead to an undesirable height of the cross-member relative to the roof. The main object of the invention is to provide a fixing foot of the type in question, by virtue of which the cable constituting the loop is not subject to an excessive tensile stress, for a given gripping force, but which none the less has an acceptable length so that, from the aerodynamic point of view, the load-carrying cross-member remains at a reasonably low height above the surface of the motor-vehicle roof. According to the invention, this object is achieved by means of a fixing foot as claimed. By virtue of this concept, as will be understood better from the description with reference to the drawings, the two portions of the loop situated on the inner and outer sides of the rail are substantially parallel to one another so that they are subjected to a tensile stress substantially equal to half of that to which they would be subjected if, with the sides parallel, one end of the loop (the anchoring ends or the tip) were fixed. The arrangement according to the invention in fact corresponds to a half pulley system of which the pulley is constituted by the rail. With this arrangement, for a given tensile stress on the cable, the travel which the nut portion has to perform is halved in comparison with the travel which it would have to perform if one of the ends of the loop were fixed. As a result, the fixing foot of the cross-member of the foot can have vertical dimensions which are within acceptable limits from the aerodynamic point of view. The invention also relates to a load-carrying cross-member having a pair of such fixing feet. The invention will become clearer from a reading of the following detailed description of a preferred embodiment thereof, given by way of non-limiting example and illustrated in the appended drawings, in which: Figure 1 is a perspective view showing part of a motor-vehicle roof and of one of the two longitudinal rails fixed to the roof and an end portion of a load-carrying cross-member having a fixing foot according to the invention, the latter being shown in the course of being fixed to the rail, Figure 2 is an exploded perspective view showing the fixing foot of Figure 1 and its closure cover, Figure 3 is a section through the foot and its cover, Figure 4 is a section taken in the plane indicated IV-IV in Figure 3. With reference to Figure 1, a motor-vehicle roof T has a pair of fixed longitudinal rails R. A tubular load-carrying cross-member 10 of square cross-section has a pair of feet for fixing to the rail R, of which only one foot, generally indicated 12, is shown. With reference to Figures 1 to 3, the foot 12 comprises a sheet-metal body 14 blanked and formed into a channel-shape which is open outwards laterally and at the top. The body 14 comprises, amongst other things, a rear wall 16 corresponding to the inner side of the rail R and a pair of cheeks 18. The rear wall 16 is extended by an appendage 20 which is fitted in the tubular cross-member 10 and is fixed, by means of a rivet 22, to the lower wall of this cross-member 10, together with a larger flange 24 of a shaped sheet-metal bracket 26 which will be referred to further below. The body 14 has a lower soft pad 28 of rubber or plastics material which bears on the rail R and abuts onto the inner side of the rail. A nut-and-bolt tensioning device, generally indicated 30, is housed in the space defined between the rear wall 16 of the body 14 and the two cheeks 18 thereof. The tensioning device 30 comprises a bolt 32 which extends through a hole 34 in the larger flange 24 of the bracket 26. The bolt 32 has a hexagonal socket head 36 which abuts onto the shoulder constituted by the larger flange 24, from above. A slide 38 in the form of a shaped element, for example, of diecast metal is associated with the bolt 32. A nut 40 engaged on the bolt 32 is incorporated in the slide 38. A substantially inextensible loop 42 is associated with the tensioning device 30. The loop 42 is preferably constituted by a cable comprising a thin steel wire rope covered by a sheath of PVC or other plastics material. Two end portions of the loop 42 are indicated 44 and a tip of the loop, opposite the two end portions 44, is indicated 46. With further reference to the slide 38, this comprises a bracket-like portion 48 which, as shown in Figure 4, has a pair of holes 50 disposed side by side. The bracket 48 is situated on the inner side of the foot 12, adjacent the rear wall 16. The two end portions 44 of the loop 42 are threaded through the holes 50 and have crimped anchoring sleeves 52 which react against the bracket-like portion 48 from above. On the other side of the nut 40, that is, on the outer side of the slide 38, the slide has an upwardly-open hooked member 54. The hooked member 54 constitutes an engagement member for the tip 46 of the loop 42. In order to fix the foot 12 to the rail R, the installer places the foot 12 so that it bears on the rail R by means of the pad 28 and pulls the loop 42 towards himself from the inside toward the outside, approximately as shown in chain line in Figure 1 and as indicated by the arrow F. The installer then lifts the tip 46 of the loop 42, wrapping the loop 42 around the rail R from below and finally hooks the tip 46 of the loop onto the engagement member 54. The arrangement in which the loop 42 is anchored to the slide 38 on the inner side of the rail R whilst the engagement member 54 is situated on the outer side is advantageous since the installer can hook the tip 46 of the loop into the engagement member 54 whilst following this operation with his eyes rather than groping blindly as he would have to do if the engagement member 54 were situated on the inner side of the rail R as in the document DE-U-82 29 446. Once the hooking has been performed, as shown in Figure 1, the installer rotates the bolt 32 with a hexagonal wrench W in the direction corresponding to the raising of the nut 40 and of the slide 38 until the loop 42 is tightened firmly around the rail R. For security reasons, as well as for aesthetic reasons, a shell-like cover 56 of metal or strong plastics material is associated with the body 14 of the foot 12. This cover 56 can be fixed firmly to the body 14 and is shaped so as to complete the shape of the foot 12, closing the foot at the side and at the top so as to render the tensioning device 30 inaccessible. A lock 58 with a key is used to fasten the cover 56. The lock 58 comprises a substantially rectangular rotatable catch 60. The bracket 26 in turn comprises a smaller front flange 62 bent at right angles and having a rectangular window 64. The arrangement and the configuration of the catch 60 and of the window 64 are such that the catch 60 can pass through the window 64 only when the catch is oriented in a predetermined position in which the cover 56 is free. When the lock 58 is operated in the closure direction by means of its key, the catch 60 engages behind the smaller flange 62 and can no longer come out through the window 64, thus fixing the cover 56 firmly to the body 14 and preventing ill-intentioned access to the head 36 of the bolt in order to loosen the bolt and release the loop 42 from the engagement member 54.

Claims: A foot for fixing a load-carrying cross-member (10) to a longitudinal rail (R) of a motor-vehicle roof (T), comprising a body (14) fixed to one end of the cross-member (10) and shaped for bearing on the rail (R) and for reacting against an inner side of the rail, the body (14) containing a tensioning device with a bolt (32) and a nut (40), of which the bolt (32) has a head (36) operable from above and reacting against a shoulder (24) fixed to the body (14), there being anchored to a nut portion (38, 40) of the tensioning device two ends (44) of a loop (42) which is intended to extend under the rail (R) and a tip (46) of which is intended to be hooked onto an engagement member (54) of the foot (12), the arrangement being such that rotation of the bolt (32) in one direction tensions the loop (42), fastening the rail (R) between the body (14) and the loop, characterized in that the engagement member (54) is fixed to the nut portion (38, 40). A fixing foot according to Claim 1, characterized in that the nut portion (38, 40) consists of a slide in the form of a shaped element in which the nut (40) is incorporated, in that , on one side of the nut (40), the slide (38). has a bracket-like portion (48) with a pair of holes (50), disposed side by side, through which the ends (44) of the loop (42) can extend, in that the ends (44) of the loop (32) have anchoring sleeves (52) which react against the bracket-like portion (48) from above, and in that , on the other side of the nut (40), the slide (38) has an upwardly-open hooked element (54) which constitutes the said engagement member. A fixing foot according to Claim 1 or Claim 2, characterized in that the ends (44) of the loop (42) are anchored to the nut portion (38) in a position corresponding to the inner side of the rail (R) and the engagement member (54) is situated in a position corresponding to the outer side of the rail (R). A fixing foot according to Claim 3, characterized in that the body (14) of the foot (12) is constituted by a channel-shaped element which is open outwards laterally and at the top, with a rear wall (16) corresponding to the inner side of the rail (R) and with a pair of cheeks (18) which frame the tensioning device (30), the head (36) of the screw (32) being accessible from above between the cheeks (18), and in that a shell-like cover (56) associated with the body (14) of the foot (12) can be fixed firmly to the body and is shaped so as to complete the shape of the foot (12), closing the foot laterally and at the top in order to render the tensioning device (30) inaccessible. A fixing foot according to Claim 4, characterized in that the shell-like cover (56) has a lock (58) with a key, and with a rotatable catch (60), and the body (14) of the foot (12) has, between its cheeks (18), an engagement flange (62) which has a window (64) through which the catch (60) can pass only when it is oriented in a predetermined position, the shell (56) being fixed firmly to the body (14) when the catch (60) is disposed behind the flange (62) and is thus oriented so that it cannot pass through the window (64). A fixing foot according to Claim 5, characterized in that its body (14) comprises, in an upper portion thereof, a shaped bracket (26) with a larger flange (24) having a hole (34) through which the bolt (32) can extend and constituting the shoulder for the head (36) of the bolt (32), and with a smaller front flange (62) which has the window (64). A load-carrying cross-member having, at its ends, a pair of fixing feet (12) according to any one of the preceding claims.

Inventors: BARAVALLE UGO, BARAVALLE, UGO
Applicants: FAPA SPA, FAPA S.P.A.
Application year: 2000
Main classification: B60R9
IPC codes: B60R9