FR3085192A1 - ASSEMBLY COMPRISING A FIXING DEVICE AND A SCREWDRIVER - Google Patents

Abstract

The invention relates to an assembly comprising a screwdriver bit (51) and a fixing device (29). The fixing device (29) is intended to cooperate with a nut (19) and comprises a connecting screw (31) and a sleeve (41) mounted around the rod of the screw (31) and of length less than that here, the sleeve (41) is able to slide along said rod between a high position in which it is placed in abutment against the head (33) of the screw and a low position in which it is spaced from said head ( 33), and in that the assembly further comprises an elastic pressure means configured to return the sleeve (41) to the low position.

Description

ASSEMBLY COMPRISING A FIXING DEVICE AND A SCREWDRIVER

The invention lies in the field of fastening devices allowing the assembly of elements through a hollow body. The invention finds particular application to the fixing of a roof bar on a roof or on the upper part of the passenger compartment side of a motor vehicle.

Several solutions are known for fixing the longitudinal bars on the roof of a motor vehicle and, in particular, on the upper part of one side of the passenger compartment (or top of the body side). One of the problems encountered comes from the fact that this assembly is done through a hollow body formed by the top of the body side and a reinforcing element disposed between said top of the body side and the lining. It must be possible to align the assembly screw with a nut or a tapped hole while passing said screw through a hole for passage of the reinforcing element. This operation is made difficult by the positioning tolerances between the different elements during their assembly.

A solution used in the prior art and illustrated in FIG. 1 consists in using a spacer 1 with backlash. The spacer is arranged in the air gap 3 formed between said top of the body side 5 and the reinforcing element 7 The assembly screw 9 shows a washer 11 integrated into its head 13, intended to come to bear against the reinforcing element 7, and against which the socket 15 of the screwdriver is supported. The rod 17 of the screw 9 shows a sufficient length to pass through the air gap 3 and cooperate with an integrated nut 19, presented by the roof bar 21, after having passed through an opening 23 at the top of the body side 5 .

If this solution has shown good results, it nevertheless has some drawbacks. On the one hand, backlash spacers are expensive and difficult to install. On the other hand, their use implies that the air gap, as measured between the reinforcing element and the top of the body side, shows a certain height. However, it would be interesting to be able to reduce the height of this air gap to meet the current constraints in terms of shock.

Document FR1319906 proposes to fix a roof bar on a vehicle by means of a fixing screw mounted in a barrel. This solution does not make it possible to manage the positioning tolerances in a satisfactory manner.

The solution consisting in simply removing the spacer in order to reduce the height of the air gap 3 is illustrated in FIG. 2. The assembly screw 9 places its head 13 and its integrated washer 11 against the top of the body side 5. The rod 17 of the screw 9 cooperates with the nut 19 mounted on the roof bar 21. This solution is not satisfactory, because it involves making in the reinforcing element 7 a passage hole 27 large enough to allow the passage of the washer 11 of the screw 9 and of the socket 15 of the screwdriver. Furthermore, the diameter of this through hole 27 must be further enlarged to absorb the positioning clearance between the top of the body side 5 and the reinforcing element 7, which generates a non-alignment between said through hole 27 and the threaded hole of the nut 19.

Document KR20000043129 proposes fixing roof bars without a spacer by a simple threaded rod carried by said roof bar. This solution does not manage the alignment tolerances between the openings through which said threaded rod passes.

The document FR2993219 proposes to dispense with fixing washers and to place reinforcing metal plates at the level of the openings shown from the top of the body side. This solution is interesting, but adds an installation operation of said reinforcing plates in the vehicle mounting process.

Document FR3017087 proposes that the roof bar be secured to a fixing barrel intended to pass through the air gap of a double-walled structure. A screw-nut assembly is inserted into said fixing barrel. To avoid excessive play being necessary between the mounting barrel and the hole shown by the roof, or the top of the body, and in order to compensate for the problems of alignment of the different holes and through holes resulting from the tolerances of manufacturing, the necessary clearance is moved from the outside of the fixing barrel to the inside of the latter. Indeed, the presence of a play outside the fixing barrel risks giving the roof bar a tendency to spill, that is to say a tendency to rotate the roof bar along its longitudinal axis. This solution is interesting, but differs little from the play-adjusting spacers mentioned above since the fixing barrel bears on the reinforcing element.

The object of the invention is to provide a solution to the problems and drawbacks encountered in the prior art by proposing a fixing device and an arrangement which is economical, for example in that it makes it possible to overcome the presence of '' a spacer, while at the same time reducing the height of the air gap between the top of the body side and the reinforcement element while maintaining good performance on the reinforcement piece, that is to say in that that the through hole through which the fixing device will come to assemble the different elements is as small as possible.

To this end, and according to a first aspect, the invention relates to an assembly comprising a screwdriver bit and a fixing device, the fixing device being intended to cooperate with a nut or a tapped hole, the fixing device comprising a cap screw having a head and a rod with a threaded portion and showing a free end, the screw bit comprising a socket configured to receive the head of the screw; the assembly being remarkable in that the fixing device further comprises a sleeve mounted around the rod of the screw and of length less than the latter, the sleeve being able to slide along said rod between a high position in which it is placed in abutment against the head of the screw and a low position in which it is spaced from said head, and in that the assembly further comprises an elastic pressure means configured to return the sleeve to the low position.

In the low position, the sleeve is placed in direct support against the screw head or against an integrated washer when the screw head is provided with it.

As will be understood from reading the definition which has just been given, the invention is remarkable in that it provides a fixing device comprising a connecting screw and a sleeve, the sleeve having the function , among others, to play the role of washer by its lower end. The sleeve is detached from said screw since it can slide along its rod. This separation will make it possible to pass through the passage hole at the lower end of the sleeve before the thread of the screw is engaged in the nut or the tapped hole and therefore to overcome the need for good alignment different items at this point. This configuration makes it possible, in fact, to absorb the respective positioning clearances between the elements to be assembled and the through hole through which the fixing device is engaged. This configuration therefore makes it possible both to have a reduced through hole and a tolerance interval concerning the alignment of the through hole and the nut or the tapped hole. An elastic pressure means is configured to push and hold the sleeve in the low position during the assembly operation of at least two elements by means of such an assembly and in particular during the crossing of the passage hole by the end. bottom of the sleeve.

According to the invention, the elastic pressure means can be carried either by the screwdriver bit, or by the fixing device.

Also, according to a first embodiment, the elastic pressure means is a compression spring presented by the screwdriver bit. In this embodiment, the screwdriver bit will cooperate with the sleeve of the fixing device to place it in the low position. Preferably, the screwdriver bit comprises a cage having a first opening through which the head of the screw of the fixing device is intended to pass, the sleeve being slidably mounted in the cage between a separated position and a position brought closer to said first opening, said compression spring also being mounted in or on the cage and arranged to return the sleeve to its position away from the first opening.

Advantageously, the screwing tip comprises a cage having a first opening delimited at its periphery by an edge and through which the head of the screw of the fixing device is intended to pass, and the sleeve of the fixing device has a diameter outside which is larger than the dimensions of the first opening so that when the screw head is inserted into the socket, the sleeve comes to rest against the edge of the first opening and does not enter said cage.

According to a second embodiment of the invention, the elastic pressure means is a compression spring presented by the fixing device, said compression spring is arranged between the head of the screw and the sleeve. Preferably, the head of the screw comprises an integrated washer. It is understood that according to the second embodiment, the fixing device can be used in an assembly comprising a conventional screwdriver bit, with a simple socket. It is also understood that the support of the sleeve on the head of the screw is done by means of the integrated washer, that is to say by support of the sleeve on said washer.

Whether the assembly is defined according to its first or second embodiment, the assembly preferably shows a magnet disposed at the bottom of the socket of the screwdriver bit so as to retain the screw head in the socket when inserted into it; and / or the socket has a means of connection to a screwdriver.

According to a second aspect, the invention relates to a screwdriver bit for assembly according to the first embodiment of the first aspect of the invention, the tip being remarkable in that it comprises a cage having a first opening through which is intended to pass the head of the screw of the fixing device, a socket mounted to slide in the cage between a separated position and a position brought closer to said first opening and an elastic pressure means mounted in or on the cage and arranged to bring the socket in its position away from the first opening.

Preferably, the sleeve having a high end arranged on the side of the head of the screw, and the first opening being delimited at its periphery by an edge, said first opening is dimensioned to have a diameter less than the dimensions of the sleeve of the device for fixing to the level of its upper end, so that when the screw head is inserted into the socket, the sleeve comes to rest against the edge of the first opening and does not enter said cage. The dimensions of the sleeve at its upper end are defined either by the outside diameter of said sleeve, or by the diameter of a base arranged at its upper end.

Advantageously, the screwdriver bit further comprises a magnet disposed at the bottom of the socket of the screwdriver bit, so as to retain the screw head in the socket when it is inserted therein; and / or the socket has a means of connection to a screwdriver.

Preferably, the elastic pressure means is a compression spring.

According to a third aspect of the invention, the subject of the invention is a fixing device intended to be used in an assembly according to the second embodiment of the first aspect of the invention, the fixing device comprising a connecting screw provided with a head and a rod with a threaded part and showing a free end, the fixing device being remarkable in that it further comprises a sleeve mounted around the screw rod and of less length than that here, the sleeve being able to slide along said rod between a high position in which it is placed in abutment against the head of the screw and a low position in which it is spaced from said head, and in that it further comprises an elastic pressure means arranged between the head of the screw and the sleeve and configured to return the sleeve to the low position. Preferably, the elastic pressure means is a compression spring.

According to preferred embodiments, the fixing device as defined according to the third aspect or forming part of the assembly according to the first aspect, the sleeve of the fixing device being in the form of a tube and / or having a high end arranged on the side of the screw head and a lower end arranged on the side of the free end of the screw rod; the fastening device has one or more of the following characteristics:

- the lower end of the sleeve has a base; and or

- The fixing device is configured so that when the sleeve is placed in the low position, the free end of the screw rod protrudes from said sleeve; and / or the sleeve comprising an internal face and an external face, the sleeve has on its internal face a collar intended to cooperate with a shoulder presented by the screw rod when the said sleeve is placed in the low position, said collar of the sleeve being arranged between the head of the screw and the shoulder of the rod, so as to retain the sleeve on the rod of the screw; and or

- the sleeve has an inner diameter less than the diameter of the head and an outer diameter which is greater than or equal to the diameter of the screw head, preferably the upper end comprises a base.

According to a preferred implementation of the invention, the fixing device is remarkable in that the sleeve is captive.

According to a fourth aspect, the invention relates to a vehicle comprising at least three elements, including at least a first and a second element assembled by a fixing device and a sheet forming a third element, the third element being arranged so as to be opposite and at least partially separated from the second element so as to define an air gap, the vehicle being remarkable in that the fixing device is defined according to the third aspect of the invention, and cooperates with a nut or a hole threaded for the assembly of said first and second elements, and in that the fixing device is at least partially arranged in said air gap and passes through a through hole shown by said third element.

Advantageously, the first element is a roof bar, the second element is a roof or top of the body side, and the third element is a reinforcing element or a piece of lining.

Ideally, the sleeve having a lower end arranged on the side of the free end of the screw rod, said lower end showing a base, the diameter presented by the through hole shown by the third element is greater than the diameter of the base and less than 1.2 times the diameter of the base, preferably less than 1.1 times the diameter of the base.

According to a preferred embodiment, the nut or the tapped hole showing a countersink, and the rod of the screw having a shoulder intended to cooperate with a collar presented by the internal face of the sleeve, the vehicle is remarkable in that the screw is dimensioned so that the length L1 of its rod, as measured between its free end and said shoulder, corresponds to the following relation (I):

L1 <H + P (I) in which,

H is the height of the air gap between the second and the third element, and

P is the depth of the counterbore of the nut or tapped hole.

Thus, the screw of the fixing device is dimensioned so that its threaded part is not yet engaged in the complementary threading of the nut or of the tapped hole when the base of the sleeve passes through the passage hole of the third element.

According to an alternative or complementary embodiment, the nut or the tapped hole showing a counterbore, and the screw rod having a shoulder intended to cooperate with a collar presented by the internal face of the sleeve, the sleeve having a lower end arranged on the side of the free end of the screw rod; said lower end being disposed in abutment against the second element, the vehicle is remarkable in that the screw is dimensioned so that the length L2 of its rod, as measured between said shoulder and the end of its threaded part closest to its free end, responds to the following relation (II):

L2> P + E + D + X (II) in which,

P is the depth of the counterbore of the nut or of the tapped hole,

E is the thickness shown by the assembled elements as measured between the lower end of the sleeve and the countersinking of the nut or the tapped hole, D is the distance between the collar of the sleeve and its lower end, and

- X is greater than at least one pitch of the thread of the threaded part of the rod.

Preferably, X is greater than or equal to 3 times the thread pitch of the threaded part of the screw rod.

Thus, the screw of the fixing device is dimensioned so that its threaded part is engaged in the complementary threading of the nut or of the tapped hole when the base of the sleeve is placed in abutment against the surface of the second element.

According to a fifth aspect, the invention relates to the use of an assembly according to the first aspect for fixing a roof bar on a sheet forming a top of the body side or the roof of a motor vehicle. Preferably, the use is made in a vehicle according to the fourth aspect.

According to a sixth aspect, the invention relates to the use of a screwdriver bit according to the second aspect for fixing a roof bar on a sheet forming a top of the body side or a roof of a vehicle automobile. Preferably, the use is made in a vehicle according to the fourth aspect.

According to a seventh aspect, the invention relates to the use of a fixing device according to the third aspect for fixing a roof bar on a sheet forming a top of the body side or the roof of a vehicle automobile. Preferably, the use is made in a vehicle according to the fourth aspect.

According to an eighth aspect, and a first implementation of the invention, the subject of the invention is a method of assembling at least two elements by means of an assembly comprising a fixing device comprising a connecting screw , and a nut or a tapped hole shown by the first element, the second element having an aperture aligned with said tapped hole or the hole of said nut for the passage of said assembly screw, the assembly being carried out by the passage of said fixing device through a passage hole shown by a sheet forming a third element, the third element being arranged so as to be opposite and at least partially spaced from the second element so as to define an air gap , the method being remarkable in that it comprises the following stages:

- supply of a set according to the first aspect comprising a screwdriver bit according to the second aspect and a fixing device;

engagement of the head of the screw in the socket of said screwdriver bit, and insertion of the fixing device into said socket so that the edges of the first opening of the cage are placed in abutment against the upper end of the sleeve, and the sleeve being placed in a position separated from the first opening, the sleeve is placed in the low position on the screw; preferably, the head of the screw is held in position in the socket by the action of a magnet disposed at the bottom of said socket;

- engagement of the fixing device through the passage hole of the third element and the free end of the screw in the nut or the tapped hole; and

- screwing the screw until the head of the screw is placed against the sleeve.

According to a second implementation of the invention, the invention relates to a method of assembling at least two elements by means of an assembly comprising a fixing device comprising a connecting screw, and a nut or a tapped hole shown by the first element, the second element having an aperture aligned with said tapped hole or the hole of said nut for the passage of said assembly screw, the assembly being carried out by the passage of said device fixing through a passage hole shown by a sheet forming a third element, the third element being arranged so as to be opposite and at least partially spaced from the second element so as to define an air gap, the method being remarkable in that it includes the following steps:

- supply of an assembly according to the first aspect comprising a screwdriver bit and a fixing device according to the third aspect, preferably comprising an integrated washer;

- engagement of the head of the screw in the socket of said screwdriver bit, and insertion of the fixing device into said socket so that the edges of the socket are placed in abutment against the integrated washer or so that the bottom of the sleeve is placed in abutment against the top of said head; the sleeve being placed in the low position on the screw by an elastic pressure means arranged between the screw head and an external shoulder of the sleeve;

- engagement of the fixing device through the passage hole of the third element and the free end of the screw in the nut or the tapped hole; and

- screwing the screw until the head of the screw is placed against the sleeve.

Preferably, and according to the first and / or the second implementation of the invention, the screw of the fixing device is dimensioned so that its threaded part is not yet engaged in the complementary threading of the nut or of the tapped hole. when the base of the sleeve passes through the through hole of the third element.

Preferably, and according to the first and / or the second implementation of the invention, the screw of the fixing device is dimensioned so that its threaded part is engaged in the complementary threading of the nut or of the tapped hole when the sleeve base is placed in abutment against the surface of the second element.

The invention will be well understood and other aspects and advantages will appear clearly on reading the following description, given by way of example with reference to the accompanying drawing plates in which:

Figures 1 and 2 illustrate fastening systems according to the prior art.

Figure 3 shows a fixing device according to the invention.

FIG. 4 illustrates a screw for assembling a fixing device according to the invention without its sleeve.

Figures 5 and 6 are sectional views along the cutting plane A-A of Figure 3 and illustrate the sliding of the sleeve along the rod of the assembly screw.

Figures 7 and 8 are sectional views of a screwdriver bit according to the invention.

Figures 9 to 11 illustrate different stages of the assembly method according to a first implementation of the invention by means of an assembly and a vehicle according to the invention.

Figure 12 shows a fixing device according to the invention in its variant with elastic pressure means.

Figure 13 is a sectional view along the cutting plane B-B of Figure 12 and illustrates the sliding of the sleeve along the rod of the connecting screw under the effect of the elastic pressure means.

Figures 14 to 16 illustrate different stages of the assembly method according to a second implementation of the invention by means of an assembly and a vehicle according to the invention.

In the following description, the term "understand" is synonymous with "include" and is not limiting in that it authorizes the presence of other elements in the assembly, the fixing device, the end piece or the vehicle to which it relates. It is understood that the term "understand" includes the terms "consist of". In the different figures, the same references designate identical or similar elements.

Figures 1 and 2 having been described in the introductory part, reference will first be made to Figure 9, illustrating the invention according to a first implementation. In the following description, the fixing device, the vehicle and the assembly method will be described jointly.

The invention relates to a fixing device 29 making it possible to assemble at least two elements (5, 21) through a hollow body. One of the elements to be assembled 5 forms one of the walls of said hollow body, the wall of the opposite hollow body is a sheet forming a third element 7 and showing a through hole 27 through which the fixing device 29 is engaged for the purpose of 'assembly of said at least two elements (5, 21). One of the elements to be assembled 21 has a nut 19 or a threaded hole which is arranged to be aligned with said passage hole 27 of the sheet forming the third element 7. There is therefore a gap 3 with a height "H> > between the third element 7 and one of the elements to be assembled 5, thus defining the hollow body.

With reference to FIG. 3, it can be seen that the fixing device 29 according to a first embodiment of the invention comprises a connecting screw 31 provided with a head 33 and a rod 35 with a threaded part 37 and showing a free end 39. Said screw 31 is also illustrated in FIG. 4. Returning to FIG. 3, it can be seen that the fixing device 29 further comprises a sleeve 41, preferably captive, mounted around the rod 35 of the screw 31 and of length less than the length thereof. The sleeve 41 is able to slide along said rod 35 between a high position (illustrated in FIG. 5) in which it is placed in abutment against the head 33 of the screw 31 and a low position (illustrated in FIG. 6) in which it is spaced from said head 33. A high end arranged on the side of the head 33 of the screw 31 and a low end arranged on the side of the free end 39 of the rod 35 of the screw will therefore be defined on said sleeve 41 31.

According to a preferred embodiment of the invention, the sleeve 41 further comprises a base 43 at its lower end. This base 43 will be positioned in abutment against one of the elements to be assembled, that is to say against the second element 5 (visible for example in FIG. 9), and act as a washer. It will be noted that said washer is carried by a sleeve 41 capable of sliding along the rod 35 of the screw. The washer (i.e. the base of the sleeve) is therefore detached from the rod 35 of the screw.

According to an embodiment of the invention illustrated in Figures 5 and 6, the possibilities of sliding of the sleeve 41 along the rod 35 are limited. Thus, preferably, the fixing device 29 is configured so that, when the sleeve 41 is placed in the low position, the free end 39 of the rod 35 protrudes from the sleeve 41.

The free end 39 of the screw 31 may be roughly rolled or chamfered and be formed by the end of the threaded part 37 of the screw 31, or as in a preferred embodiment, show a pilot end. Assembly screws comprising conical or cylindrical pilot tips are known to the skilled person. The presence of a pilot end facilitates the insertion, positioning and alignment of the screw 31 with the nut 19 (visible for example in Figure 9) or the tapped hole during the assembly operation. The presence of a pilot end is also advantageous because the insertion of the end of the screw 31 into the nut 19 or the tapped hole is done blind for the fitter, the third element masking said nut 19 or said tapped hole. Advantageously, as can be seen in FIG. 9, the nut 19 or the tapped hole have a countersink 49.

Returning to Figure 5, it will be understood that the sleeve 41 is in the general form of a tube. In order to limit the displacement of the sleeve 41 along the rod 35 of the screw 31, the sleeve 41 comprising an internal face and an external face, the sleeve preferably has, on its internal face, a collar 47 intended to cooperate with a shoulder 45 presented by the rod 35 of the screw 31. This cooperation takes place during the placement of said sleeve 41 in the low position, as illustrated in FIG. 6, the collar 47 then being placed in abutment against the shoulder 45. This configuration allows ensuring on the one hand that the end 39 of the rod 35 of the screw 31 protrudes from the sleeve 41 when it is in the low position and on the other hand that the sleeve 41 is retained on the rod 35 of the screw 31 at least at its lower end.

Furthermore, the collar 47 of the sleeve 41 is arranged between the head 33 of the screw 31 and the shoulder 45 shown by the rod 35 of the screw 31. Advantageously, the sleeve 41 has an internal diameter smaller than the diameter of the head 33 of the screw 31. This configuration makes it possible to retain the sleeve 41 on the rod 35 of the screw 31 at least at its upper end. When it is retained on the rod 35 of the screw 31 both at its low end and its high end, the sleeve 41 is captive.

According to a preferred implementation of the invention, the outside diameter of the sleeve 41 is greater than or equal to the outside diameter of the head 33 of the screw 31. Preferably, the outside diameter of the sleeve 41 is greater than the outside diameter of the head 33 of the screw 31. This configuration allows a screwing tool, for example a screwdriver provided with a screwing tip 51 (visible in Figures 9 to 11) to bear on the sleeve 41 during the assembly operation at least two elements (5, 21) by the fixing device 29. In a complementary or alternative manner, the upper end of the sleeve also comprises a base 69 for this purpose.

The screwing tip 51 according to the invention is illustrated in Figures 7 and 8. In this preferred implementation of the invention, the screwing tip 51 comprises an elastic pressure means 53 configured to return the sleeve to the low position . To this end and according to a preferred embodiment, the screwing tip 51 comprises a cage 55 having a first opening 57 through which is intended to pass the head of the screw of the fixing device, and a socket 15, for example with a hexagonal imprint 25 is slidably mounted in the cage 55 between a separated position (illustrated in FIG. 7) and a close position (illustrated in FIG. 8) of said first opening 57. The elastic pressure means 53 is preferably a compression spring mounted in the cage 55 and arranged to return the sleeve 15 to its position separated from the first opening 57. According to a variant not shown, the elastic pressure means is mounted on the external face of the cage and cooperates with lugs of the sleeve accessible through oblong holes extending in the longitudinal direction of the cage.

Advantageously, and as illustrated in FIGS. 10 and 11, the sleeve 41 has an upper end arranged on the side of the head 33 of the screw, possibly provided with a base 69. The first opening 57 is delimited at its periphery by an edge 59 Said first opening 57 is dimensioned to have a diameter less than the dimensions of the sleeve 41 of the fixing device at its upper end, and when it is present, of its base 69, so that when the head 33 of the screw is inserted into the sleeve 15, the sleeve 41 comes to rest against the edge 59 of the first opening 57, and does not enter said cage 55.

Preferably, and as illustrated in FIGS. 7 and 8, the screwing tip 51 further comprises a magnet 61 disposed at the bottom of the socket 15, so as to retain the head 33 of the screw in the socket 15 when it is inserted there. More preferably, the sleeve 15 has a connection means 63 to a screwdriver. Said connection means 63 passes through a second opening 65 of the cage 55, opposite to the first opening 57. The sleeve 15 is retained in the cage 55 at the second opening 65 by a retaining element 67, such as a circlip .

Returning to FIGS. 9 to 11, it will be understood that the separation of the sleeve 41 and the screw 31 is particularly advantageous in that it makes it possible to drill a through hole 27 on the third element 7 as small as possible while keeping a tolerance of positioning between the different elements as to their alignment. As illustrated in FIG. 10, the invention will in fact allow, during the assembly operation, to pass the lower end of the sleeve 41, therefore the base 43 of the sleeve 41 acting as a washer, through the hole of passage 27 of the third element 7 before the threaded part 37 of the assembly screw 31 (referenced in FIGS. 3 and 4) is engaged in the complementary threading of the nut 19 or of the tapped hole.

It is easy to understand that, to do this, the dimensions of the fixing device 29 are adapted to the dimensions of the arrangement of the various elements in question and in particular to the height H of the air gap 3 that the fixing device 29 must pass through. Thus, preferably, the rod 35 of the screw having a shoulder 45 intended to cooperate with a collar 47 presented by the internal face of the sleeve 41, the screw 31 is dimensioned so that the length L1 of its rod 35, as measured between its free end 39 and said shoulder 45, ie less than the height H of the air gap 3.

When the nut 19 or the tapped hole shows a countersink 49, and the rod 35 of the screw 31 has a shoulder 45 intended to cooperate with a collar 47 presented by the internal face of the sleeve 41, the screw 31 is dimensioned so that the length L1 of its rod 35, as measured between its free end 39 and said shoulder 45, corresponds to the following relation (I):

L1 <H + P (I) in which,

H is the height of the air gap 3 between the second 5 and the third element 7, and

P is the depth of the countersink 49 of the nut 19 or of the tapped hole.

The value of P is zero in the absence of counterbore.

It is thus possible to firstly pass the base 43 of the sleeve 41 into the hole 27 for passage of the third element 7 and then slightly shift the fixing device 29 from its coaxial position relative to the passage hole 27 for place the screw 31 in alignment with the nut 19 or the tapped hole for screwing.

According to an implementation of the invention, the diameter presented by the through hole 27 is greater than the diameter of the base 43 of the sleeve 41 and less than 1.3 times the diameter of the base 43 of the sleeve 41 at from its lower end, preferably less than 1.2 times the diameter of the base 43, more preferably less than 1.1 times the diameter of the base 43. This configuration is particularly advantageous when the third element 7 is a reinforcement piece which must not show too large openings in order to be able to provide satisfactory performance in terms of impact and effort resistance.

During the assembly operation, once the through hole 27 and once the free end 39 of the screw 31 has engaged in the nut 19 or the tapped hole, the lower end of the sleeve 41 will come place in abutment against the surface of the second element 5 to be assembled. It is then important that at the time when this support is made, the threaded part 37 of the assembly screw 31 is already engaged in the complementary threading of the nut 19 or of the tapped hole. The screwing of the screw 31 in the nut 19 or the tapped hole then slides the sleeve 41 along the rod 35 of the assembly screw 31 from its low position to its high position. The upper end of the sleeve 41 then comes to rest against the head 33 of the screw 31 as illustrated in FIG. 11 and the assembly is then tightened allowing the assembly of the first and second elements.

To meet this need, the fixing device 29, and in particular the assembly screw 31, must be dimensioned with respect to the dimensions of the first 5 and second 21 elements to be assembled.

Thus, according to a preferred implementation of the invention, the nut 19 or the tapped hole showing a counterbore 49, and the rod 35 of the screw 31 having a shoulder 45 intended to cooperate with a collar 47 presented by the internal face of the sleeve 41, the sleeve 41 having a lower end arranged on the side of the free end 39 of the rod 35 of the screw 31 and intended to be placed in abutment against one of the elements to be assembled, the screw 31 is dimensioned so that the length L2 of its rod 35, as measured between said shoulder 45 and the end of its threaded part 37 closest to its free end 39, corresponds to the following relation (II):

L2> P + E + D + X (II) in which,

P is the depth of the counterbore 49 of the nut 19 or of the tapped hole,

E is the thickness shown by the assembled elements (5, 21) as measured between the surface of the second element against which the sleeve 41 is intended to bear and the entry of the countersink 49 of the nut 19 or of the tapped hole , D is the distance between the collar 47 of the sleeve 41 and its lower end, and

- X is greater than at least one pitch of the thread of the threaded part 37 of the rod 35 of the screw 31.

The distance D between the collar 47 of the sleeve 41 and its lower end is illustrated in FIG. 5. When the nut 19 is integrated into the first element 21 so as to be placed in abutment against the second element 5, the thickness E is l thickness of the second element. When the first and second elements are both sheets intended to be clamped between the nut and the base of the sleeve, the thickness E is the cumulative thickness of the two sheets.

When the nut or the tapped hole has no counterbore, the relationship will have to be filled in by taking a zero value for the depth P of the counterbore.

If it suffices that the screw 31 is engaged with a thread to initiate the sliding of the sleeve 41 along its rod 35, the skilled person will have advantage that the screw 31 is engaged by at least two and preferably at least three threads when the base 43 of the sleeve 41 comes to rest on the surface of the second element 5 to be assembled. This is why, the person skilled in the art will preferentially choose X as being greater than or equal to 2 times the pitch of the thread of the threaded part 37 of the screw 31, and preferably greater than or equal to 3 times the pitch of the thread of the threaded part 37 of screw 31.

The invention finds a particular application in the fixing of roof bars so that the first element 21 is a roof bar, the second element 5 is a roof panel or top of the body side, and the third element 7 either a reinforcing element or a lining piece.

Reference will now be made to FIGS. 12 to 16 illustrating a preferred variant of the invention according to which the elastic pressure means 53 is carried by the fixing device 29.

According to this embodiment, the fixing device 29 comprises a connecting screw 31 provided with a head 33 and a rod 35 with a threaded part 37 and showing a free end 39. In a similar manner to the previous variant, the fixing device 29 further comprises a sleeve 41 mounted around the rod 35 of the screw 31 and of length less than this, the sleeve 41 being able to slide along said rod 35 between a high position (illustrated in Figures 12 and 16) in which it is placed in abutment against the head 33 of the screw and a low position (illustrated in FIGS. 13 and 14) in which it is moved away from said head 33.

The characteristics concerning the dimensions L1 and L2 of the screw 31, the presence of a shoulder 45 as illustrated in FIG. 4, are also valid in this variant of the invention. Likewise, the sleeve 41 can advantageously have a collar 47 and a base 43 at its lower end. The particularity of this variant of the fixing device 29 is that it further comprises an elastic pressure means 53, preferably a compression spring 53 arranged between the head 33 of the screw and the sleeve 41 and configured to bring back the sleeve 41 in the low position.

Preferably, the elastic pressure means 53 is supported on a shoulder 71 arranged on the external face of the sleeve 41 and arranged to be separated from its upper end, so that the upper end of the sleeve can be placed in abutment against the head 33 of the screw directly. More preferably, the head of the screw has an integrated washer 73 on which the elastic pressure means 53 will bear.

The assembly method is the same as for the previous embodiment, with the difference that the screwing tip can consist of a simple socket 15, and that it will be supported either on the head 33 of the screw when the socket has a bottom of a suitable depth; either on the integrated washer 73 of the screw head 33, as illustrated in FIGS. 15 and 16.

The assembly method therefore comprises the engagement of the head 33 of the screw in the socket 15 of said screwdriver, and driving the fixing device 29 into said socket 15 so that the edges of the socket 15 are placed in support against the integrated washer 73, or so that the bottom of the sleeve is placed in abutment against the top of said head. The sleeve 41 is placed in the low position on the screw 31 by an elastic pressure means 53 arranged between the head 33 of the screw and an outside shoulder 71 of the sleeve 41.

The fixing device 29 is engaged through the passage hole 27 of the third element 7 and the free end 39 of the screw 31 is engaged in the nut 19 or the tapped hole. The screw 31 is then screwed until the head 33 of the screw is placed in abutment against the sleeve 41.

Claims (10)

1. Assembly comprising a screwdriver bit (51) and a fixing device (29), the fixing device (29) being intended to cooperate with a nut (19) or a tapped hole, the fixing device (29) comprising a cap screw (31) having a head (33) and a rod (35) with a threaded part (37) and showing a free end, the screwdriver bit (51) comprising a socket (15 ) configured to receive the head (33) of the screw (31); the assembly being characterized in that the fixing device (29) further comprises a sleeve (41) mounted around the rod (35) of the screw (31) and of length less than this, the sleeve (41 ) being able to slide along said rod (35) between a high position in which it is placed in abutment against the head (33) of the screw (31) and a low position in which it is spaced from said head (33 ), and in that the assembly further comprises an elastic pressure means (53) configured to return the sleeve (41) to the low position. 2. Assembly according to claim 1 characterized in that the elastic pressure means (53) is a compression spring presented by the screwdriver bit (51). 3. An assembly according to claim 1 characterized in that the elastic pressure means (53) is a compression spring presented by the fixing device (29), said compression spring is arranged between the head (33) of the screw ( 31) and the sleeve (41); preferably, the head (33) of the screw (31) comprises an integrated washer (73). 4. An assembly according to claim 1 to 3, characterized in that a magnet is disposed at the bottom of the socket (15) of the screwing tip (51) so as to retain the head (33) of screws (31 ) in the socket (15) when inserted therein. 5. screwing bit (51) for assembly according to one of claims 1, 2 or 4, the bit (51) being characterized in that it comprises a cage (55) having a first opening (57) through which is intended to pass the head (33) of the screw (31) of the fixing device (29), a sleeve (15) slidably mounted in the cage (55) between a separated position and a position brought closer to said first opening (57 ) and an elastic pressure means (53) mounted in or on the cage (55) and arranged to return the sleeve (15) to its position spaced from the first opening (57). 6. A fixing device (29) intended to be used in an assembly according to one of claims 1, 3 or 4, the fixing device (29) comprising a connecting screw (31) provided with a head (33 ) and of a rod (35) with a threaded part (37) and showing a free end (39), the fixing device (29) being characterized in that it further comprises a sleeve (41) mounted around the rod (35) of the screw (31) and of length less than this, the sleeve (41) being able to slide along said rod (35) between a high position in which it is placed in abutment against the head (33) of the screw (31) and a low position in which it is spaced from said head (33), and in that it further comprises an elastic pressure means (53) arranged between the head (33) of the screw (31) and the sleeve (41) and configured to return the sleeve (41) to the low position. 7. Assembly according to one of claims 1 to 4, or fixing device (29) according to claim 6; the sleeve (41) of the fixing device (29) being in the form of a tube and / or having a top end arranged on the side of the head (33) of the screw (31) and a bottom end arranged on the side of the 'free end (39) of the rod (35) of the screw (31), characterized in that the lower end of the sleeve (41) has a base (43). 8. Vehicle comprising at least three elements, including at least a first (21) and a second (5) element assembled by a fixing device (29) and a sheet forming a third element (7), the third element (7) being arranged so as to be opposite and at least partially spaced from the second (5) element so as to define an air gap (3), the vehicle being characterized in that the fixing device (29) is defined according to the one of claims 6 or 7, and cooperates with a nut (19) or a threaded hole for the assembly of said first (21) and second (5) elements, and in that the fixing device (29) is at least in part disposed in said air gap (3) and passes through a through hole (27) shown by said third element (7). 9. Vehicle according to claim 8, the nut (19) or the tapped hole showing a counterbore (49), and the rod (35) of the screw (31) having a shoulder (45) intended to cooperate with a collar ( 47) presented by the internal face of the sleeve (41), the vehicle is characterized in that the screw (31) is dimensioned so that the length L1 of its rod (35), as measured between its free end (39) and said shoulder (45) responds to the following relation (I): L1 <H + P (I) in which, H is the height of the air gap (3) between the second (5) and the third element (7), and P is the depth of the countersink (49) of the nut (19) or of the tapped hole. 10. Vehicle according to one of claims 8 or 9, the nut (19) or the threaded hole showing a counterbore (49), and the rod (35) of the screw (31) having a shoulder (45) intended to cooperate with a collar (47) presented by the internal face of the sleeve (41), the sleeve (41) having a low end arranged on the side of the free end (39) of the rod (35) of the screw (31) , said lower end being disposed in abutment against the second element (5), the vehicle is characterized in that the screw (31) is dimensioned so that the length L2 of its rod (35), as measured between said shoulder (45 ) and the end of its threaded part (37) closest to its free end (39), corresponds to the following relation (II): L2> P + E + D + X (II) in which, P is the depth of the countersink (49) of the nut (19) or of the tapped hole, E is the thickness shown by the assembled elements as measured between the lower end of the sleeve (41) and the countersink inlet (49) of the nut (19) or of the tapped hole, D is the distance between the collar (47) of the sleeve (41) and its lower end, and - X is greater than at least one pitch of the thread of the threaded part (37) of the rod (35); preferably, X is greater than or equal to 3 times the pitch of the thread of the threaded part (37) of the rod (35) of the screw (31).