fastening device

Abstract

The invention relates to a fastening device (10), the fastening device (10) comprising: - a head (20); - a foot (30) extending from a lower face (21) of the head (20), the foot (30) being intended to be inserted into the opening; - at least one guiding means (40), formed on the foot (30), intended to impose a first angular position on said foot (30) upon its insertion into the opening, the guiding means (40) being configured to allow rotation of the foot (30) once the head (20) is against the first face (2), towards a second angular position, a position preventing any movement of the foot (30) along the principal axis X; - a flexible tab (50), carried by the foot (30), and configured to cooperate with the notch (3b) in order to oppose the rotation of said foot (30). Figure to be published with the abbreviation: Fig. 3

Description

Title of the invention: fastening device FIELD OF THE INVENTION

[0001] The present invention relates to the field of fastening devices. In particular, the present invention concerns a fastening device equipped with a stop and anti-return system of improved reliability and robustness compared to existing systems. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] In many industrial sectors, the quick and secure fastening of parts to a support is a major concern. Effective fastening solutions are essential not only for improving operational efficiency but also for ensuring the stability and safety of assemblies. Among the available fastening methods, the quarter-turn fastener stands out for its ability to provide quick, simple, and reliable fastening.

[0003] Traditional fastening systems, such as screws, nuts, and rivets, while effective in many applications, have several drawbacks. They often require specialized tools for installation and removal, which can increase labor time and costs. Furthermore, these methods can lead to wear on the components, thus reducing their lifespan and necessitating frequent replacements.

[0004] In environments where speed and efficiency are crucial, such as automotive assembly lines, aerospace equipment, and modular structures, these limitations can pose significant challenges. Furthermore, the safety of fasteners is a constant concern, as faulty fasteners can lead to costly and potentially dangerous malfunctions.

[0005] Quarter-turn fastening devices offer an ideal solution to these problems. They allow for quick fastening with a simple rotation, for example, 90 degrees. These fastening devices are generally equipped with stop and anti-return systems designed to secure the fastening device against the opening of a support.

[0006] However, these stop and anti-return systems are subject to stresses which may lead to their failure.

[0007] Thus, one object of the present invention is to propose a fastening device whose structure makes it possible to overcome the disadvantages listed above. BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the present invention is achieved by a device for fixing a part to a support, the support comprising an opening provided with at least one notch delimited by two lateral walls, the fixing device comprising:

[0009] - a head intended to be supported by a lower face against a first face of the support;

[0010] - a foot which extends, from an underside of the head, along a principal axis X, the foot being intended to be inserted, by its free end, into the opening;

[0011] - at least one guiding means, formed on the foot, intended to impose, by cooperation with at least one notch, a first angular position of said foot when inserted into the opening, the guiding means is also configured to allow rotation of the foot around the main axis X, when the head is in contact with the first face, towards a second angular position, a position preventing any movement of the foot along the main axis X;

[0012] - at least one flexible tongue, carried by the foot, and configured to cooperate with at least one notch to oppose the rotation of said foot when the latter is in the second angular position.

[0013] According to one embodiment, the foot has a generally cylindrical shape, and includes at least one secondary zone forming a band which extends from the lower face towards the free end of said foot, the radius of curvature of at least one secondary zone being less than the radius of curvature of the rest of the foot, at least one flexible tab being carried by at least one secondary zone.

[0014] According to one embodiment, at least one flexible tongue is configured to flex around at least one axis, called the flex axis and perpendicular to the principal axis X, towards the foot during the insertion of said foot into the opening by sliding said at least one flexible tongue against an edge of the opening, and to deploy when the foot is in the second angular position.

[0015] According to one embodiment, at least one flexible tongue includes a locking section extending from a free edge essentially perpendicular to the main axis X, the locking section being intended to be interposed between the two side walls, and to butt against one or the other of said side walls when a rotational movement is imposed on the foot.

[0016] According to one embodiment, the locking section is configured to impose a first resistance when a rotational force is exerted on the foot in a direct direction of rotation, and to impose a second resistance, less than the first resistance, when a rotational force is exerted on the foot in an indirect direction of rotation opposite to the direct direction of rotation.

[0017] According to one embodiment, the at least one flexible tongue comprises, in a direction from the free end of the foot towards the underside, a first section and a second section, the first section being mechanically attached to the foot by one of its sides, called the connection side, parallel to the main axis X.

[0018] According to one embodiment, the at least one flexible tongue comprises a rib, called a flex rib, extending parallel to the main axis, said flex rib having a thickness increasing over at least the first section in the direction from the free end of the foot towards the lower face so that, when the foot is inserted into the opening, a sliding of the flex rib induces an internal bending at the foot of said at least one flexible tongue.

[0019] According to one embodiment, at least one flexible tongue includes a transverse rib disposed perpendicular to the principal axis X on an external face of the locking section.

[0020] According to one embodiment, the transverse rib extends from a first side, opposite the connecting side, to a second side of the second section, the transverse rib having a first thickness at the level of the first side and a second thickness, less than the first thickness, at the level of the second side.

[0021] According to one embodiment, at least one flexible tab includes a notch partially separating the first section from the second section and extending perpendicularly to the principal axis X and from the connecting side.

[0022] According to one embodiment, the foot includes at least one lateral opening through one side from which at least one flexible tongue extends from its origin.

[0023] According to one embodiment, at least one flexible tongue is formed by a concavely curved wing, the at least one tongue being mechanically joined by two of its adjacent sides, respectively called the lateral connection side and the lower connection side, and comprises two adjacent free sides, the locking section forming an inflection with the outer surface of the foot from the connection side.

[0024] According to one embodiment, at least one tab extends, in the direct direction of rotation, from the lateral connection side towards one of its free sides, and in a direction going from the free end towards the lower face, from its connection side towards the other of its free sides.

[0025] According to one embodiment, at least one guiding means comprises a structure of divergent shape in a direction from the free end towards the lower face, and terminates, in this direction, with a terminal stop, said terminal stop being intended to oppose the withdrawal of the foot from the opening once it is in the second angular position.

[0026] According to one embodiment, the at least one guiding means comprises, in order, and in a direction from the free end to the lower face, a main rib and a triangular shape.

[0027] According to one embodiment, the main rib has, in the direction from the free end to the lower face, an increasing thickness.

[0028] According to one embodiment, the triangular shape comprises two oblique ribs which extend divergently from one of their ends from the main rib and symmetrically to each other with respect to the direction of elongation of the main rib, the two other ends being connected by a transverse rib forming the terminal stop.

[0029] According to one embodiment, the main rib extends along the entire triangular shape, said triangular shape comprising horizontal ribs extending each on either side of the main rib, and in a symmetrical manner.

[0030] According to one embodiment, each horizontal rib being in the shape of a rhombus provided, in order and in a direction going from the free end towards the lower face, with a small base and a large base.

[0031] According to one embodiment, the small base of a horizontal rib, called the downstream rib, being of a length less than the length of the large rib base which immediately precedes the downstream rib in the direction going from the free end towards the lower face.

[0032] According to one embodiment, said fastening device is a single piece. BRIEF DESCRIPTION OF FIGURES

[0033] Other features and advantages of the invention will become apparent from the detailed description of the invention which follows with reference to the accompanying figures in which:

[0034] [Fig.1] Fig.1 is a schematic representation of a support with an opening suitable for implementing the present invention, in particular, the opening shown in Fig.1 comprises a circular section and two notches diametrically opposed to each other;

[0035] [Fig.2] Fig.2 is a schematic representation of a first example of a fastening device according to the present invention, in particular the fastening device is represented in perspective view;

[0036] [Fig.3] The [Fig.3] is a schematic and partial representation of the fixing device when the foot is inserted into the opening, in particular when the foot is inserted, the guiding means pass through at least one notch and thus impose the first angular position on the foot;

[0037] [Fig.4] The [Fig.4] is a representation of the foot fully inserted into the opening and in the first angular position;

[0038] [Fig.5] The [Fig.5] is a representation of the foot fully inserted into the opening and in the second angular position;

[0039] [Fig.6] The [Fig.6] is a schematic representation of the device of the [Fig.2] and allowing to illustrate the means of guidance;

[0040] [Fig.7] The [Fig.7] is a schematic representation of a first variant relating to the guiding means;

[0041] [Fig.8] The [Fig.8] is a schematic representation of a second variant relating to the guiding means;

[0042] [Fig.9] The [Fig.9] is a schematic representation of the foot according to the present invention allowing to detail the characteristics of the flexible tongue;

[0043] [Fig. 10] The [Fig. 10] is a schematic representation of the foot according to the present invention allowing to detail the characteristics of the flexible tongue;

[0044] [Fig. 11] The [Fig. 11] is a schematic representation of a flexible tongue according to a second example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] The present invention relates to a device for attaching a part to a support. In particular, and without limiting the invention to this aspect alone, the part may include a tailgate stop.

[0046] The fastening device is designed to cooperate with an opening formed in a support. Such a support 1 is illustrated in particular in [Fig. 1]. This support 1, formed by a plate, includes on one of its faces, called the first face 2, an opening 3, and more specifically a through opening. The opening 3 comprises a circular section 3a and at least one notch 3b arranged radially with respect to the circular section, thus forming a tabbed opening. The opening 3 may include a single notch 3b, two notches 3b, or even more, distributed at regular angular intervals.

[0047] It is understood that the support 1 has a given thickness which corresponds to the distance between the first face 2 and a second face of the support, parallel and opposite to the first face 2. This thickness can also be considered as the depth of the opening 3.

[0048] A notch 3b is delimited by two lateral walls 4a and 4b, opposite each other and advantageously essentially parallel. Each of these lateral walls 4a and 4b forms an edge with the wall, called the main wall 4c, of the circular section 3a. The notch 3b is also delimited by a peripheral wall 4d connecting the lateral walls 4a and 4b.

[0049] The remainder of the description will be limited to the consideration of a single notch 3b or two notches 3b. Thus, a person skilled in the art will be able to adapt the principles described and generalize the invention to a larger number of notches.

[0050] The invention therefore relates to a device for fixing a part to a support, the support comprising an opening provided with at least one notch delimited by two lateral walls, the fixing device comprising:

[0051] - a head intended to be supported by a lower face against a first face of the support;

[0052] - a foot which extends, from an underside of the head, along a principal axis X, the foot being intended to be inserted, by its free end, into the opening;

[0053] - at least one guiding means, formed on the foot, intended to impose, by cooperation with at least one notch, a first angular position of said foot when inserted into the opening, the guiding means is also configured to allow rotation of the foot around the main axis X, when the head is in contact with the first face, towards a second angular position, a position preventing any movement of the foot along the main axis X;

[0054] - at least one flexible tongue, carried by the foot, and configured to cooperate with at least one notch to oppose the rotation of said foot when the latter is in the second angular position.

[0055] The invention can advantageously be implemented to fix a tailgate stop, an interface element, a clip, a roof support... to a support

[0056] Advantageously, the foot generally has a cylindrical shape and comprises at least one secondary zone, bearing at least one flexible tab, and forming a band extending from the underside towards the free end of said foot. The radius of curvature of the secondary zone is advantageously smaller than the radius of curvature of the rest of the foot.

[0057] At least one secondary zone, as defined above, creates a space between this zone and the edge of the circular section 3a, allowing at least partial accommodation for the presence of at least one flexible tab. This feature advantageously reduces the play between the circular section 3a and the foot when the latter is inserted into the opening, by adjusting the diameter of the circular section 3a to that of the foot.

[0058] Advantageously, at least one flexible tongue is configured to flex around at least one axis, called the flex axis and perpendicular to the main axis X, towards the foot during the insertion of said foot into the opening by sliding said at least one flexible tongue against an edge of the opening, and to deploy when the foot is in the second angular position.

[0059] This configuration allows for progressive flexing and unfolding of at least one flexible tongue during, respectively, the insertion of the foot into the opening and the rotation of the foot from the first angular position to the second angular position.

[0060] Advantageously, at least one flexible tongue includes a locking section extending from a free edge essentially perpendicular to the main axis X. This locking section is intended to be interposed between the two side walls, and to butt against one or the other of said side walls when a rotational movement is imposed on the foot.

[0061] Advantageously, the locking section is configured to offer a first resistance when a rotational force is exerted on the foot in a direct direction of rotation, and to offer a second resistance, lower than the first resistance, when a rotational force is exerted on the foot in an indirect direction of rotation opposite to the direct direction of rotation.

[0062] Also advantageously, the locking section can also be configured so that during rotation of the foot in the direct direction of rotation the deployment of at least one flexible tab is progressive.

[0063] In particular, the locking section can be configured so that, during rotation of the foot in the direct direction of rotation, it cooperates, notably by sliding, with one of the edges formed between one of the side walls 4a and 4b and the main wall 4c in such a way as to allow the progressive deployment of at least one tab. This configuration may involve a shape and / or a variation in the thickness of the locking section.

[0064] The remainder of the statement will give at least two examples to illustrate this latter aspect. However, these examples are not intended to limit the invention. In particular, a person skilled in the art will be able, based on their general knowledge and the instruction provided in this description, to implement other configurations of the locking section.

[0065] In [Fig.2], we can see a first example of a fastening device 10. The fastening device 10 according to the present invention can comprise a plastic material and thus be obtained by molding.

[0066] Advantageously, the fastening device 10 can be one piece.

[0067] The fastening device 10 according to the present invention comprises a head 20 and a foot 30.

[0068] The head 20 can be circular in shape, and comprise two principal faces essentially parallel to each other and called, respectively, lower face 21 and upper face 22.

[0069] The foot 30 extends from the lower face 21 of the head 20 along a principal axis X, the foot being designed to be inserted, by its free end 31, into the opening 3. It is understood that the foot 30 extends perpendicularly to the lower face. The complete insertion of the foot 30 into the opening 3 results in the lower face being pressed against the first face 2 of the support 1.

[0070] The foot 30 may be cylindrical in shape. More particularly, the foot 30 may include at least one secondary zone 32 forming a band extending from the lower face 21 towards the free end of said foot, the radius of curvature of at least one secondary zone being less than the radius of curvature of the rest of the foot, at least one flexible tab being carried by at least one secondary zone.

[0071] It is understood that a strip according to the present invention is laterally delimited by two generatrices of the cylinder. Furthermore, the expression "remainder of the foot" shall designate a main zone distinct from and adjacent to at least one secondary zone. In particular, the main zone may be a section of a cylinder of revolution.

[0072] It is also understood that the main zone and the secondary zone are components of the lateral surface of the cylinder forming the foot 30.

[0073] It is also accepted that both the main zone and the secondary zone can be distributed into several sections. In particular, the main zone can comprise two sections, each formed by a strip extending from the lower face 21 to the free end 31 of the foot 30, each strip being laterally delimited by two generatrices of the cylinder forming the foot.

[0074] The two main zones may advantageously have the same geometric characteristics and be diametrically opposed to each other.

[0075] Equivalently, the secondary zone may comprise two sections each formed by a band extending from the lower face 21 to the free end of the foot 30, each band being laterally delimited by two generatrices of the cylinder forming the foot.

[0076] The two secondary zones 32 can advantageously have the same geometric characteristics and be diametrically opposed to each other.

[0077] Thus, the secondary zones and the main zones are formed alternately on the lateral surface of the foot.

[0078] The fastening device 10 is also provided with at least one guide means 40, formed on the foot 30. The at least one guide means 40 may in particular comprise two guide means 40 diametrically opposed to each other.

[0079] It is understood that the guiding means 40 are formed on a lateral surface of the foot 30, and in particular on the main area.

[0080] A guiding means 40, according to the terms of the present invention, is in particular configured to impose, by cooperation with at least one notch 3b, a first angular position of said foot 30 when it is inserted into the opening 3. The guiding means is also configured to allow the rotation of the foot around the main axis X, when the head is in contact with the first face 2, towards a second angular position, a position preventing any movement of the foot along the main axis X.

[0081] According to the present invention, the guide means 40 forms a local enlargement of the foot 30 which is thus able to interfere with the edge of the circular section 3a of the opening 3. The notch or notches thus provide a passage for at least one guide means allowing the foot 30 to be inserted into the opening 3 according to the first angular position ([Fig.3]).

[0082] By way of example, the at least one guiding means 40 comprises a structure of divergent shape in a direction going from the free end towards the lower face, and terminates, in this direction, with a terminal stop 41, said terminal stop 41 being intended to oppose the withdrawal of the foot from the opening when it is in the second angular position.

[0083] In particular, the terminal stop 41 provides, with the lower face 21, a spacing, of a dimension at least equal to the depth of the opening so as to be able to accommodate a contour area of ​​the circular section by rotation of the foot from the first angular position to the second angular position.

[0084] Figure 4 is a representation of the foot 30 fully inserted into the opening 3 and in the first angular position. The spacing between the end stop 41 and the lower face 21 allows rotation of the foot around the principal axis X from the first angular position to the second angular position (Figure 5).

[0085] By way of example, the at least one guiding means 40 comprises in order, and in a direction going from the free end 31 to the lower face 21, a main rib 42 and a triangular shape 43.

[0086] Advantageously, the main rib 42 has, in the direction from the free end to the lower face, an increasing thickness.

[0087] According to a first variant of this first example illustrated in [Fig. 7], the triangular shape 43 comprises two oblique ribs 43a and 43b which extend divergently from one of their ends, from the main rib 42 and symmetrically to each other with respect to the elongation direction X of the main rib 42, towards their other ends. The two other ends are connected by a transverse rib forming the terminal stop 4L

[0088] According to a second variant of this first example illustrated in [Fig. 8], the main rib 42 extends along the entire length of the triangular shape 43, said triangular shape comprising horizontal ribs 44 extending symmetrically on either side of the main rib. According to this second variant, each horizontal rib 44 may be rhomboid-shaped, having, in order and in a direction from the free end towards the lower face, a small base and a large base.

[0089] The smaller base of a horizontal rib, called the downstream rib, is advantageously shorter than the larger base of the preceding rib. The downstream rib is immediately aligned in the direction from the free end towards the lower face. This geometry helps to limit interference between these horizontal ribs and the lateral walls of the notches when the foot is inserted into opening 3.

[0090] The fastening device also includes at least one flexible tab 50, carried by the foot 30, and configured to cooperate with at least one notch 3b in order to oppose the rotation of said foot when the latter is in the second angular position.

[0091] In particular, at least one flexible tab 50 is configured to flex about at least one axis, referred to as the flex axis and perpendicular to the principal axis X, towards the foot during insertion of said foot into the opening 3 by sliding said at least one flexible tab 50 against an edge of the opening, and to extend when the foot is in the second angular position. In particular, the flexible tab 50 extends from a lower side 51 towards a free edge 52 in the direction from the free end 31 towards the lower face 21.

[0092] It is understood that the flexibility of at least one tongue is not limited to flexibility only around the bending axis perpendicular to the principal axis X. In particular, the flexible tongue can also bend around an axis parallel to said principal axis X.

[0093] The at least one flexible tongue 50 includes a locking section 53 which extends from the free edge 52 essentially perpendicular to the principal axis X. More particularly, the locking section 53 is intended to be interposed between the two lateral walls 3b when the foot is in the second angular position, and to butt against one or the other of said lateral walls when a rotational movement is imposed on the foot.

[0094] Advantageously, the locking section 53 can be configured to impose a first resistance when a rotational force is exerted on the foot in a direct direction of rotation, and to impose a second resistance, lower than the first resistance, when a rotational force is exerted on the foot in an indirect direction of rotation opposite to the direct direction of rotation.

[0095] Thus, and according to this first example, the at least one flexible tongue 50 can comprise, in a direction going from the free end of the foot towards the lower face, a first section 54 and a second section 55, the first section 54 being mechanically fixed to the foot by one of its sides, called the connection side 56, parallel to the principal axis X. According to this configuration, the direct direction of rotation follows the direction going from the connection side 56 towards a free side of the first section and opposite to the connection side.

[0096] Advantageously, the at least one flexible tongue 50 may include a rib, referred to as a flex rib 57, extending parallel to the main axis. This flex rib has a thickness that increases over at least the first section in the direction from the free end of the foot towards the underside, such that, when the foot is inserted into the opening, a sliding of the flex rib against the edge of the circular section 3a induces an internal bending at the foot of said at least one flexible tongue. The flex rib is advantageously located on the side of the first section opposite the connecting side 56.

[0097] The at least one flexible tongue 50 may include a transverse rib 53a disposed perpendicular to the principal axis X on an external face of the locking section 53. In other words, the transverse rib 53a forms the locking section 53.

[0098] Advantageously, the transverse rib extends from a first side 58a, opposite the connecting side 56, to a second side 58b of the second section. The transverse rib has a first thickness at the first side and a second thickness, less than the first thickness, at the second side. Furthermore, as soon as the foot is inserted into the opening and in the second angular position, the transverse rib is sandwiched between the lateral walls 4a and 4b. In particular, the first side 58a faces the lateral wall 4a, while the second side 58b faces the lateral wall 4b.

[0099] Thus, a rotational force exerted on the foot in the direct direction of rotation will cause the first side to abut against the lateral wall 4a, while a rotational force exerted on the foot in the indirect direction of rotation will cause the second side to abut against the lateral wall 4b. Therefore, and insofar as the first thickness is greater than the second thickness, the resistance to a rotational force exerted on the foot in the direct direction of rotation will be greater than the resistance to the same force exerted on the foot in the indirect direction of rotation.

[0100] Advantageously, at least one flexible tongue includes a notch 59 partially separating the first section from the second section and extending perpendicularly to the principal axis X and from the connecting side. This notch makes the second section more flexible and thus facilitates unlocking the foot when a rotational force is applied to it in the indirect direction of rotation.

[0101] Advantageously, the foot comprises at least one lateral opening 60 housing at least one flexible tongue. In particular, the flexible tongue advantageously originates from one side of said lateral opening 60.

[0102] Figure 11 shows a second example of a fastening device according to the present invention. This second example essentially reproduces the characteristics relating to the first example. In this second example, the at least one flexible tongue 50 is formed by a concavely curved wing, the at least one tongue being mechanically attached to the foot by its connecting side 56 and its lower side 51. The flexible tongue 50 also includes two adjacent free sides while the locking section extends, in the direct direction of rotation, from the connecting side 56 to a side opposite to said connecting side.

[0103] The locking section forms, in particular, a bend with the outer surface of the foot at the connection side. In particular, the bend forms a stop intended to cooperate with the lateral wall 4b.

[0104] Advantageously, at least one tab extends, in the direct direction of rotation, from the connecting side 56 towards one of its free sides, and in a direction going from the free end towards the lower face, from its connecting side towards the other of its free sides.

[0105] The person skilled in the art will find in document EP 2 422 096 B1 all the information necessary for the implementation of a flexible tongue formed by a curved wing.

[0106] Of course the invention is not limited to the described method(s) of implementation and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Demands

1. A fastening device (10) for a part to a support (1), the support (1) comprising an opening (3) having at least one notch (3b) delimited by two lateral walls (4a, 4b), the fastening device (10) comprising: - a head (20) intended to bear by a lower face (21) against a first face (2) of the support (1); - a foot (30) which extends, from a lower face (21) of the head (20), along a principal axis X, the foot (30) being intended to be inserted, by its free end (31) into the opening (3);- at least one guiding means (40), formed on the foot (30), intended to impose, by cooperation with at least one notch (3b), a first angular position of said foot (30) when it is inserted into the opening (3), the guiding means (40) is also configured to allow the rotation of the foot (30) around the principal axis X, when the head (20) is in contact with the first face (2), towards a second angular position, a position preventing any movement of the foot (30) along the principal axis X; - at least one flexible tab (50), carried by the foot (30), and configured to cooperate with at least one notch (3b) in order to oppose the rotation of said foot (30) when the latter is in the second angular position.

2. A fastening device (10) according to claim 1, wherein the foot (30) has a generally cylindrical shape, and comprises at least one secondary zone (32) forming a band extending from the lower face (21) to the free end (31) of said foot (30), the radius of curvature of the at least one secondary zone (32) being less than the radius of curvature of the rest of the foot (30), the at least one flexible tab (50) being carried by the at least one secondary zone (32).

3. A fastening device (10) according to claim 1 or 2, wherein at least one flexible tab (50) is configured to flex about at least one axis, referred to as the flex axis and perpendicular to the principal axis X, towards the foot (30) during the insertion of said foot (30) into the opening (3) by sliding said at least one flexible tab (50) against an edge of the opening (3), and to deploy when the foot (30) is in the second angular position.

4. A fastening device (10) according to claim 3, wherein at least one flexible tongue (50) comprises a locking section (53) extending from a free edge (52) essentially perpendicular to the principal axis X, the locking section (53) being intended to be interposed between the two side walls (4a, 4b), and to butt against one or the other of said side walls when a rotational movement is imposed on the foot (30).

5. A fastening device (10) according to claim 4, wherein the locking section (53) is configured to impose a first resistance when a rotational force is exerted on the foot (30) in a direct direction of rotation, and to impose a second resistance, less than the first resistance, when a rotational force is exerted on the foot (30) in an indirect direction of rotation opposite to the direct direction of rotation.

6. A fastening device (10) according to claim 4 or 5, wherein at least one flexible tongue (50) comprises, in a direction from the free end (31) of the foot (30) to the lower face (21), a first section (54) and a second section (55), the first section (54) being mechanically attached to the foot (30) by one of its sides, called the connecting side, parallel to the main axis X.

7. A fastening device (10) according to claim 6, wherein at least one flexible tongue (50) comprises a rib, said flex rib, extending parallel to the main axis, said flex rib (57) having a thickness increasing over at least the first section (54) in the direction from the free end (31) of the foot (30) to the lower face (21) such that, when the foot (30) is inserted into the opening (3), a sliding of the flex rib (57) induces an internal bending at the foot (30) of said at least one flexible tongue (50).

8. A fastening device (10) according to claim 6 or 7, wherein at least one flexible tab (50) comprises a transverse rib (53a) disposed perpendicular to the principal axis X on an external face of the locking section (53).

9. A fastening device (10) according to claim 8, wherein the transverse rib extends from a first side (58a), opposite the connecting side (56), to a second side (58b) of the second section (55), the transverse rib having a first thickness at level of the first side (58a) and a second thickness, lower than the first thickness, at the level of the second side (58b).

10. A fastening device (10) according to any one of claims 6 to 9, wherein at least one flexible tab (50) includes a notch partially separating the first section (54) from the second section (55) and extending perpendicularly to the principal axis X and from the connecting side (56).

11. A fastening device (10) according to any one of claims 6 to 10, wherein the foot (30) comprises at least one lateral opening through one side of which at least one flexible tongue (50) extends from its origin.

12. A fastening device (10) according to claim 5, wherein at least one flexible tongue (50) is formed by a concavely curved wing, the at least one tongue being mechanically secured by two of its adjacent sides, referred to respectively as the lateral connecting side (56) and the lower connecting side (56), and comprising two adjacent free sides, the locking section (53) forming an inflection with the outer surface of the foot (30) from the connecting side (56).

13. A fastening device (10) according to claim 12, wherein at least one tab extends, in the direct direction of rotation, from the lateral connecting side (56) to one of its free sides, and in a direction from the free end (31) to the lower face (21), from its connecting side (56) to the other of its free sides.

14. Fixing device (10) according to any one of claims 1 to 13, wherein at least one guiding means (40) comprises a structure of divergent shape in a direction from the free end (31) to the lower face (21), and terminates, in this direction, in a terminal stop (41), said terminal stop (41) being intended to oppose the withdrawal of the foot (30) from the opening (3) when it is in the second angular position.

15. A fastening device (10) according to claim 14, wherein at least one guiding means (40) comprises, in order, and in a direction from the free end (31) to the lower face (21), a main rib (42) and a triangular shape (43).

16. A fastening device (10) according to claim 15, wherein the main rib (42) has, in the direction from the free end (31) towards the lower face (21), an increasing thickness.

17. A fastening device (10) according to claim 15 or 16, wherein the triangular shape (43) comprises two oblique ribs (43a, 43b) which extend divergently from one of their ends from the main rib (42) and symmetrically to each other with respect to the elongation direction of the main rib (42), the other two ends being connected by a transverse rib (53a) forming the terminal stop (41).

18. A fastening device (10) according to claim 15 or 16, wherein the main rib (42) extends along the triangular shape (43), said triangular shape (43) comprising horizontal ribs (44) extending each on either side of the main rib, and in a symmetrical manner.

19. A fastening device (10) according to claim 18, in which each horizontal rib is diamond-shaped and provided, in order and in a direction from the free end (31) to the lower face (21), with a small base and a large base.

20. A fastening device (10) according to claim 19, wherein the small base of a horizontal rib, referred to as the downstream rib, is of a length less than the length of the large rib base which immediately precedes the downstream rib in the direction from the free end (31) to the lower face (21).

21. A fastening device (10) according to any one of claims 1 to 20, wherein said fastening device (10) is monobloc.

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