TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a detachable preassembled fastening device for assembling mechanical elements together, notably elements that are at least partially panel shaped, in particular vehicle body elements, and a system including this fastening device.

TECHNICAL BACKGROUND

[0002] Known fastening devices used to fasten a sound-proofing panel to a hood often do not enable the sound-proofing panel to be easily removed from the hood without damaging or losing the device.

[0003] If the fastening device is preassembled onto a sound-proofing panel, the known solutions often comprise several components (clip and washer, etc.), which is expensive and requires the part to be held reliably, i.e. such that the part cannot be lost, between the supplier’s preassembly site and the manufacturer’s assembly line, as well as during any disassembly operations required. Furthermore, another solution involves using plasti-rivets or clips assembled line-side by the assembler. The problem in this case is that the operator has to hold the sound-proofing panel and install the plasti-rivet or clip in the related seat simultaneously. In this case, components of the assembly system may be lost as a result of disassembly.

[0004] A preassembled detachable fastening device is known from document WO 2018/044709 Al. This device enables a sound-proofing panel to be mounted on the panel of a hood, for example.

[0005] This fastening device has a base extending between two substantially flat faces. A through-hole extends between the two faces of the base. An anchoring foot, a retaining member and two teeth extend from one side of the base, from one of the faces. The anchoring foot, the retaining member and the two teeth can be inserted into through-holes formed in the mechanical elements to be linked together, which are at least partially panel shaped. The anchoring foot has two walls that are parallel to one another and arranged on either side of a through-hole in the base. The anchoring foot also has two attachment lobes, each being mounted tiltingly in relation to the two parallel walls on a respective side of the central space delimited by the walls. The two teeth are L-shaped and arranged on the base on either side of the pair of parallel walls. Each of the teeth has one end projecting towards the walls. The retaining member has two flexible arms that are arranged on the base on either side of the pair of teeth, and an annular cage extending between the flexible arms.

The retaining member is shaped such that the flexible arms can be bent towards the base such as to engage the annular cage with the teeth. The flexible arms can then sandwich, link together and hold together the mechanical elements.

[0006] This fastening device can also be disassembled by pressing the lower portion of the lobes, i.e. partly away from the base, using a tool to disengage the lobes from the edge of the through-hole (or the through-holes where several mechanical elements are linked together).

[0007] One drawback of this known fastening device is the volume thereof, as a result of the successive widthwise positioning of parallel walls, teeth and arms.

[0008] The invention is therefore intended to propose a preassembled detachable fastening device to fasten mechanical elements that are at least partially panel-shaped to be linked together. This fastening device should enable a panel to be easily removed and reinstalled on another panel, such as a sound-proofing panel on the inside of a hood. This fastening device should also be simple to manufacture, reliable, compact and inexpensive.

SUMMARY OF THE INVENTION

[0009] The invention therefore relates to a fastening device that is connectable to a first mechanical element and to a second mechanical element, in particular mechanical elements belonging to a vehicle body, the fastening device comprising:

- a base with at least one through-hole,

- an anchoring foot comprising a core and two lobes, the core extending transversely from one side of the base, the lobes extending from the core towards the base, each lobe having a shoulder extending across the longitudinal direction of the lobe and an end facing the through-hole and forming a disassembly tab, - a retaining member extending from said side of the base, the retaining member having two flexible arms that are linked by an annular cage, the flexible arms extending on either side of the anchoring foot, the fastening device supporting a deployed state, in which each of the arms extends alongside the core, and a folded state, in which each of the arms is folded back onto itself such is to have two sections that are substantially parallel to said side of the base, in which the cage surrounds the anchoring foot and in which the cage is held in position in relation to the base.

[0010] In this case, the anchoring foot has at least one shoulder extending across the longitudinal direction thereof, and the cage is snap-fitted against this shoulder when in the folded state.

[0011] This layout of the fastening device is therefore compact and simple to manufacture. [0012] The following features can also be included in the invention:

- the shoulder is positioned on said core, the shoulder on the core is positioned at a distance from the base that is less than the distance between the base and the shoulder on a lobe,

- an outer surface of at least one lobe is provided with rough areas to form gripping means, preferably ribs extending across the longitudinal direction of the at least one lobe,

- a gap is provided between the disassembly tabs and a respective outer edge of the at least one through-hole,

- the core is provided with a pin at an end opposite the base, both the core and at least one lobe having an inclined or rounded surface converging towards the pin and forming and insertion surface,

- the base has two through-holes, each end being aligned with a respective through-hole,

- the base has a single through-hole, the core having two walls that are spaced apart from one another, an inner surface of each wall being level with a surface of the through-hole,

- at least one lobe is mounted on a distal end of the walls, - at least one lobe extends through a respective through-hole, one end forming a disassembly tab that is level with or set back from a surface of the base opposite the anchoring foot.

[0013] The invention also relates to a system for detachably linking a first mechanical element to a second mechanical element, which are preferably vehicle body elements, including a fastening device as claimed in one of the preceding claims, a first through- perforation formed through the first mechanical element that is smaller than the transverse dimensions of the base of the fastening device and designed to be traversed by the cage and the flexible arms when the fastening device is in the deployed state, and that is smaller than the full transverse dimension of the flexible arms when the fastening device is in the folded state, such that the fastening device remains preassembled against the first mechanical element when the cage is snap-fitted onto the shoulder on the core, and a second through- perforation that is formed through the second mechanical element and designed to be traversed by the lobes to snap-fit onto the shoulder of the lobes.

SHORT DESCRIPTION OF THE FIGURES

[0014] Other features and advantages of the invention are given in the detailed description provided below with reference to the attached drawings, in which:

[0015] Figure 1 is a perspective view of a first embodiment of a fastening device according to the invention,

[0016] Figure 2 is a side view of the fastening device in figure 1,

[0017] Figure 3 is a top view of the fastening device in figure 1,

[0018] Figure 4 is a bottom view of the fastening device in figure 1,

[0019] Figure 5 is a side view of the fastening device in figure 1, pivoted through 90° in relation to the view in figure 2 and arranged to face a perforation in a first mechanical element,

[0020] Figure 6 is a side view of the fastening device mounted on the first mechanical element and arranged to face a perforation in a second mechanical element, [0021] Figure 7 is a side view of the fastening device mounted on the two mechanical elements shown in figure 6, detachably linking said elements together,

[0022] Figure 8 shows the assembly in figure 7 from a point of view turned 90° in relation to the point of view shown in figure 7,

[0023] Figure 9 is a perspective view of a second embodiment of the fastening device, [0024] Figure 10 is a perspective view of a third embodiment of the fastening device. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the description provided below, a preassembled detachable fastening device 1, 101 or 201 according to the invention is used to link a first mechanical element 2 and a second mechanical element 3, for example respectively a sound-proofing panel 2 and a panel 3 of a car hood (figures 5 to 8), or other vehicle body elements that are at least partially panel shaped, i.e. having at least one linking subportion that is panel-shaped. The mechanical elements 2 and 3 are respectively provided with perforations 4 and 5 through which the fastening device 1 is designed to be inserted.

[0026] A fastening device 1 according to a first embodiment of the invention (figures 1 to 8) includes a base 11, an anchoring foot 20 and a flexible retaining member 41.

[0027] Hereinafter, the terms “proximal” and “distal” are used in relation to the base 11. The term “distal” refers to elements positioned on the side of the base 11 and the term “proximal” refers to elements positioned on the side opposite the base 11, i.e. elements removed from the base.

[0028] The base 11 is an annular plate that extends between two opposite faces 13 and 14. The base 11 has at least one through-hole 12 that extends between the faces 13 and 14. In the first embodiment, the base 11 has two holes 12 on either side of a central wall 22 that is described below. The holes 12 extend radially away from one another up to a respective outer edge 15.

[0029] The anchoring foot 20 has a core 21 and two lobes 31. An anchoring foot structure 20 as described below provides the fastening device 1 with high mechanical strength. [0030] The core 21 has a proximal end 24 from which the core extends, transversely to the base 11 and from the face 14. In one specific variant, the face 13 opposite the face 14 is rounded to enable a good mechanical link with the core 21.

[0031] In the first embodiment, the core 21 has a single central wall 22 (see in particular figure 3) having the following on either side and from the proximal end 24: a longitudinal surface 23, a shoulder 25 projecting outwards from the longitudinal surface 23, an inclined surface 26 and a frustoconical surface 27. Finally, a pin 28, which is in this case substantially cylindrical, is provided at the distal end of the core 21 opposite the base 11. The pin 28 enables the easy centering of the fastening device 1 in the perforation 4 and compensates for any play between the perforations 4 and 5. The pin 28 also acts as entry point for injecting material (position of the injection threshold) in order to ensure the uniform distribution of the material in the part.

[0032] The lobes 31 are walls that extend from the core 21 towards the base 11. In other words, the lobes 31 extend in a direction opposite the direction of extension of the core 21 from the base 11. The lobes 31 are attached by a distal end 32 to the core 11. The distal end 32 therefore forms a connection point between the lobes 31 and the core 11. Each lobe 31 has a proximal end 33 that is aligned with a respective through-hole 12, for example facing said through-hole, and opposite the distal end 32. The outer face of the lobes 31 has, from the proximal and 33: a longitudinal surface 36, a shoulder 35 and a rounded surface 38.

[0033] The shoulder 35 projects outwards from the longitudinal surface 36 (figure 2).

[0034] The rounded surface 38 extends from the shoulder 35 towards the distal end 32.

The rounded surfaces 38 thus converge with the inclined surfaces 26 described above towards the frustoconical surface 27. The inclined and rounded surfaces 26, 38, as well as the frustoconical surface 27 and, optionally, the pin 28 enable the fastening device 1 to be well centered in the perforations 4 and 5.

[0035] The ends 33 form disassembly tabs 34 that are accessible using a tool through the through-holes 12. The lobes 31 have a degree of flexibility and can bend towards one another, i.e. inwards. For this purpose, a gap D1 is provided between a rear face 39 of the disassembly tabs 34 and a side face 29 of the central wall 22 (see top view of the fastening device 1 in figure 3). Furthermore, a gap D2 is provided between the disassembly tab 34 and the edge 15 to enable insertion of a disassembly tool such as a pair of pliers (not shown).

[0036] The longitudinal surface 36 is provided with rough areas to form gripping means, preferably but without limitation transverse ribs 37 extending across the longitudinal direction of the lobes 31 (figures 1 and 2). These ribs 37 facilitate contact between a tool such as the aforementioned pair of pliers and the disassembly tabs 34.

[0037] Furthermore, the shoulders 25 on the core 21 are positioned at a distance HI from the base 11 that is less than the distance H2 between the base 11 and the shoulder 35 on the lobes 31.

[0038] The flexible retaining member 41 extends from the face 14 of the base 11. The retaining member 41 has two flexible arms 42 and an annular cage 43.

[0039] Each of the two arms 42 has a proximal end 47 from which the arm extends from the face 14. The arms 42 extend on either side of the anchoring foot 20 respectively.

[0040] Each arm 42 has at least two straight sections 44, a thicker section 45 and three elbow sections forming hinges 46. The elbow sections forming hinges 46 enable the arms 42 to be folded after insertion of the fastening device 1 into the perforation 4, thereby holding same. In the first embodiment, each arm has four straight sections 44, two thicker sections 45 and three elbow sections forming hinges 46.

[0041] The cage 43 extends between the distal ends 48 of the arms 42 opposite the proximal ends 47.

[0042] The cage 43 in this case has a closed annular portion 49 and two lugs 50, the lugs being optional. The section of the annular portion 49 is in this case substantially rectangular, without limitation. The annular portion 49 delimits an internal space 52 that is designed to receive the anchoring foot 20. The lugs 50 extend on either side of the annular portion 49 and outside said annular portion, at the distal ends 48. The lugs 50 make it easier to grip the retaining member 41.

[0043] Two teeth 51 are in this case formed on either side of the annular portion 49, for example projecting outwards at the end of the retaining member 41 opposite the base 11. [0044] The fastening device 1 supports a deployed state, shown in figures 1 to 5, in which each of the unfolded arms 42 extends along the core 21.

[0045] The fastening device 1 also supports a folded state, shown in figures 6 to 8, in which each arm 42 is folded onto itself. In the folded state, at least two sections 44 of each arm 42 are thus folded onto one another, substantially parallel to said side of the base 11. In the folded state, the cage 43 surrounds the anchoring foot 20 such that the anchoring foot 20 is positioned inside the space 52 delimited by the annular portion 49 of the cage 43. Furthermore, in the folded state, the cage 43 is held in position in relation to the base 11. More specifically, in the folded state, the cage 43 is snap-fitted onto the shoulder 25 on the core 21. For this purpose, the teeth 51 cooperate with the shoulders 25 when the retaining member 41 is folded towards the base 11 in the state reached by the fastening device 1 shown in figure 6.

[0046] The device 1 is for example fastened to the first mechanical element 2 then to the second mechanical element 3 as described below.

[0047] The anchoring foot 20 and the retaining member 41 are arranged to face a perforation 4 in the first mechanical element 2 (figure 5).

[0048] To preassemble the fastening device 1, the anchoring foot 20 and the retaining member 41 are inserted through the perforation 4 until the face 14 butts against a side of the first mechanical element 2. The retaining member 41 is then folded by moving the cage 43 towards the base 11 until the cage 43 snaps onto the shoulders 25 (figure 6), the cage 43 that links the two arms 42 ensuring that the fastening device 1 cannot be lost once mounted. The first mechanical element is then sandwiched between at least one thinner section 44 and the face 14 of the base 11. In the example shown in figure 6, two sections 44 of each arm 42 are in contact with the first mechanical element 2. Folding the two arms 42 thus enables the fastening device 1 to be held on the mechanical element 2 to form a subassembly 60.

[0049] In figures 7 and 8, the subassembly 60 formed by the fastening device 1 and the preassembled first mechanical element 2 is then assembled with the second mechanical element 3, the anchoring foot 20 being arranged in the perforation 5 of the second mechanical element 3. The second mechanical element 3 is then snap-fitted onto the shoulders 35 of the lobes 31.

[0050] The subassembly 60 can be separated from the second mechanical element 3 by moving the lobes 31 towards one another, and more specifically by moving the disassembly tabs 34 towards one another. The gap D2 between the disassembly tabs 34 and the end 15 in the hole 12 makes it particularly simple to insert the ends of a single disassembly tool therein, preferably, but without limitation, a pair of pliers, as mentioned above. Such disassembly can then be performed without causing any damage, which facilitates reuse of the part.

[0051] Two alternative embodiments are shown in figures 9 and 10. Hereinafter, the noteworthy structural elements are denoted by a reference number increased by 100 or 200 respectively in relation to the structural elements in the first embodiment.

[0052] In figure 9, a variant 101 of the fastening device 1 has assembly tabs 134 projecting from the base 11 instead of the tabs 34 in the first embodiment. Furthermore, the cage 143 has no lugs, unlike the cage 43 in the first embodiment.

[0053] In figure 10, a second variant 201 of the fastening device 1 has a single through- hole 212 passing through the base 211. The core 221 of the fastening device 201 then has two walls 222 that are spaced apart from one another, for example that are parallel to one another, such that an inner surface of each wall 222 is level with a surface of the through- hole 212. In this fastening device 201, the lobes 231 are mounted at the distal ends 232 of the walls 222 of the core 221. Each lobe 231 has an inclined surface 238 arranged beneath the respective shoulder 235 (which is identical in this case to the shoulder 35 in the first embodiment), forming a guide surface for positioning the device 201.