Motor vehicle bumper with radar blocking

Abstract

Assembly for a motor vehicle bumper (10), the assembly comprising a support panel (18) with a housing (20), at least one retaining hook (30); the assembly further comprising a detection device (22) in the housing (20) and held by the at least one retaining hook (30); an outer screen (28) adjacent to the housing (20); the at least one retaining hook (30) being capable of moving between a position for holding the detection device (22) in the housing (20), and a position offset from the holding position to allow insertion of the detection device (22) into the housing (20). The outer screen (28) includes locking means (54) configured to hold the at least one retaining hook (30) in the holding position in order to lock the detection device (22) in the housing (20). Figure to be published with the abbreviation: Figure 5

Description

Title of the invention: Motor vehicle bumper with radar blocking

[0001] The invention deals with low-speed frontal collisions of motor vehicles. The invention relates to the field of motor vehicle bumpers. More specifically, the invention relates to the attachment of a radar to a motor vehicle bumper. The invention also relates to a motor vehicle.

[0002] A motor vehicle is equipped at the front with impact components such as the bumper, designed to absorb the energy of a collision by deforming in a controlled manner. Furthermore, the bumper serves as a mounting surface for sensors such as cameras or radar. These sensors are then fixed to the bumper skin or to an adjacent grille.

[0003] An obstacle detection radar is commonly mounted on the front of the motor vehicle, specifically on the lower part of the bumper. A housing or cavity in the bumper cover or bumper frame accommodates the radar, so that the radar is flush with the bumper. The radar is fixed either directly to the bumper cover or grille, or to an additional mounting bracket, which is itself assembled to the bumper cover or grille. The fixing itself involves fastening means, which may be screws or hooks, for example. While screws provide a robust and reversible fixing, they require a time-consuming assembly procedure. Conversely, hook fixing is quicker for an operator to perform, but is more fragile.

[0004] Due to its position, the radar is exposed to frontal impacts. These frontal impacts, occurring at speeds below 10 km / h, known as "parking impacts," can affect the radar by causing it to slip. Even if the bumper returns to its original position after the impact, the radar may no longer function if its mounting has broken or shifted. Indeed, the radar may be misaligned, thus degrading its detection accuracy. Calibration then becomes necessary.

[0005] Document FR3133792 describes a vehicle bumper with a ventilation grille. This grille has, in its rear section and preferably in a central position, a cavity for receiving an obstacle detection radar and positioning and mounting interfaces for the subsequent installation of this radar. While this solution addresses the mounting of a radar, there is nevertheless a need to improve the strength of said mounting. This document, however, does not address the issue of the radar mounting's stability following an impact.

[0006] Document CN220053715 describes a bumper support structure, an assembly, and a vehicle, and aims to solve the problems arising from the fact that the rear of a bumper skin lacks structural support and is insufficiently strong. The bumper support structure is adapted to allow the direct mounting of a radar, which can be attached by welding, hooking, bonding, bolting, or molding. It remains necessary to maintain the stability of the radar attachment after an impact.

[0007] Document JP6583696 describes a vehicle sensor bracket that can protect a sensor from an impact by absorbing and redirecting the impact forces to the sides of the vehicle structure. The bracket is attached to the vehicle structure.

[0008] US patent 10793095 describes a protective structure for mounting a radar, capable of absorbing the energy of an impact. The radar is attached to the protective structure by bolts. The protective structure is itself connected to the bumper.

[0009] However, it is desirable to improve the system to move towards a solution that is simple in terms of assembly, avoiding the use of an additional support piece or technical interfaces that are sometimes difficult to produce in tooling to fix the radar, while ensuring good resistance of the radar fixing to a low-speed shock.

[0010] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to improve the stability of a motor vehicle's radar in the event of a collision. The invention also aims to optimize the assembly, robustness, and safety, as well as the number of parts, of a motor vehicle.

[0011] According to a first aspect, the invention provides an assembly for a motor vehicle bumper, the assembly comprising a support panel with a housing, at least one retaining hook; the assembly further comprising a detection device in the housing and held by the at least one retaining hook; an outer screen adjacent to the housing; the at least one retaining hook being able to move between a position for holding the detection device in the housing, and a position offset from the holding position in order to allow the insertion of the detection device into the housing; notable in that the outer screen comprises locking means configured to hold the at least one retaining hook in the holding position in order to lock the detection device in the housing.

[0012] It will be clearly understood that the invention proposes a radar housing directly fixed by a quick-release hook assembly system, said assembly system being reinforced and secured by the presence of a protective cover which locks the hooks. The radar is less likely to come loose following slight deformation of the bumper skin, it is no longer necessary to reposition or recalibrate it.

[0013] Direct assembly of the radar housing onto its panel reduces the number of parts to be assembled and the assembly time; the radar housing's attachment by hooks simplifies assembly, and the locking of said hooks by the access panel reinforces the strength of the radar housing's attachment during a parking bump. The radar remains functional after a minor impact, thus improving the vehicle's robustness.

[0014] Preferably, the blocking means comprise at least one blocking protrusion.

[0015] Preferably, at least one blocking protrusion includes a longitudinal branch.

[0016] Preferably, at least one retaining hook is between the detection device and the locking means.

[0017] Preferably, the blocking means extend longitudinally along the detection device.

[0018] Preferably, the detection device is a radar module.

[0019] Preferably, at least one retaining hook includes a guide bevel; the assembly is configured so that when the detection device is inserted into the housing, the detection device pushes the guide bevel in order to shift the retaining hook from the retaining position to the shifted position; the locking means extending along the guide bevel.

[0020] Preferably, at least one retaining hook protrudes from the housing onto the support panel.

[0021] Preferably, the outer screen is a cover over the housing, and the support panel forms a bumper skin.

[0022] Preferably, at least one retaining hook includes a point, the locking means include an internal chamfer suitable for cooperating with the point of the retaining hook.

[0023] Preferably, the blocking means are longitudinally at a distance from the housing.

[0024] Preferably, the housing includes a vertical wall longitudinally opposite at least one retaining hook.

[0025] Preferably, the assembly includes an air inlet protection grille, said protection grille being mounted on the support panel and having an opening surrounding the housing, the outer screen being attached to the protection grille.

[0026] Preferably, the bumper skin and symmetrical.

[0027] Preferably, the housing is open longitudinally.

[0028] Preferably, the retaining hook includes an elastic arm.

[0029] Preferably, the retaining hook is an elastic retaining hook.

[0030] According to another aspect, the invention proposes a motor vehicle, comprising a bumper with an assembly, remarkable in that the assembly conforms to the invention.

[0031] Preferably, the bumper is a front bumper.

[0032] Preferably, the assembly includes a controlled air inlet module behind the housing.

[0033] According to another aspect, the invention proposes a method for assembling a motor vehicle bumper assembly, the assembly method comprising the following steps: a) providing or making a support panel with a housing and at least one movable retaining hook between a retaining position and an offset position; b) inserting a detection device into the housing by pushing the retaining hook towards the offset position; c) fixing the detection device in the housing by the retaining hook in the retaining position; d) installing an outer screen facing the support panel; notable in that the outer screen includes locking means; the installation step d) further comprises a substep of locking at least one retaining hook in the retaining position by positioning the locking means at the level of at least one retaining hook in order to lock it.

[0034] According to another aspect, the invention proposes a method for assembling a motor vehicle bumper assembly, the assembly method comprising the following steps: a) providing or making a support panel with a housing and at least one movable retaining hook; b) inserting a detection device into the housing by pushing the retaining hook; c) fixing the detection device in the housing by the retaining hook; d) installing an outer screen opposite the support panel; notable in that the outer screen includes locking means; the installation step d) further comprises a substep of locking at least one retaining hook against the detection device by the locking means.

[0035] Each feature introduced by the expression "preferably" given in relation to one of the aspects of the invention applies to all other aspects of the invention.

[0036] The invention will be well understood and other aspects and advantages will become clear upon reading the following description, given with reference to the attached figures listed below.

[0037] Fig. 1 is a front view of a motor vehicle according to the invention.

[0038] Figure 2 is an exploded view of a vehicle bumper assembly automobile, according to the invention.

[0039] Fig. 3 shows a portion of a motor vehicle support panel comprising a motor vehicle detection device according to the invention.

[0040] Fig. 4 is a rear view of an exterior screen of a motor vehicle according to the invention.

[0041] Fig. 5 represents a horizontal cross-sectional view of a motor vehicle bumper assembly according to the invention.

[0042] Fig. 6 is a diagram of a method for assembling a motor vehicle bumper assembly according to the invention.

[0043] In the following description, the term "include" is synonymous with "include" and is not limiting in that it permits the presence of other elements in the motor vehicle or other steps in the process to which it relates. It is understood that the term "include" includes the terms "consist of." The terms "external" and "internal" shall respectively refer to what is directed outward from the vehicle and inward from the vehicle.

[0044] In this description, the terms "longitudinal," "longitudinally," "transverse," and "transversely" are used with respect to the vehicle's frame of reference in the mounting configuration. The term "longitudinal" refers to the principal direction of travel of the vehicle. The term "transverse" refers to a direction perpendicular to the principal direction of travel of the vehicle. The term "front" refers to the principal direction of travel of the vehicle. The term "rear" refers to the opposite of the front of the vehicle.

[0045] The X-axis represents the longitudinal direction, the Y-axis represents the transverse direction, and the Z-axis represents the vertical direction of the motor vehicle. These three axes define a right-handed trihedron.

[0046] In this description, the terms "vertical" and "horizontal" are not to be understood in their strict sense. Indeed, they allow an inclination of at most 20°, preferably at most 10°, more preferably at most 5°, and even more preferably at most 2°; with respect to the strict meaning of these terms.

[0047] In this description, the technical characteristics are defined in the assembly mounting configuration, unless otherwise explicitly stated.

[0048] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0049] Figure 1 represents a motor vehicle 10 according to the invention. The motor vehicle 10 comprises energy storage means and at least one motor (not shown) adapted to drive said motor vehicle 10.

[0050] The motor vehicle 10 comprises a structure 12. The structure 12 forms an outer body, or a main frame of the motor vehicle. Structure 12 delineates different compartments of the motor vehicle 10, including the passenger compartment, the cargo area, and the engine compartment (not shown). Structure 12 may be formed from an assembly of stamped and welded sheet metal parts.

[0051] The motor vehicle 10 has a front bumper system 14 on its front face. The front bumper system 14 includes internal elements hidden from view by the end user of the vehicle, such as one or more bumper crossmembers and bumper frames (not shown). These elements are capable of absorbing the energy of an impact by deforming. They reinforce a bumper skin 16 which is visible from the outside.

[0052] The bumper skin 16 comprises one or more support panels 18. Each support panel 18 is an outer panel. The support panels 18 include a front panel. The support panel 18 extends transversely across the front of the motor vehicle 10. The support panel 18 extends vertically across the front face of the motor vehicle 10.

[0053] According to an alternative of the invention, the bumper system is a rear bumper system.

[0054] The support panel 18 includes a housing 20. The housing 20 may include a cutout in the support panel 18.

[0055] A protective grille 24 is mounted on the support panel 18. The protective grille 24 may be a grille. The protective grille 24 is located in front of the support panel 18. It extends transversely and vertically across the front of the motor vehicle 10. It may house an air inlet for an air conditioning system. The protective grille 24 has an opening 26 surrounding the housing 20. A controlled air inlet module (not shown) is located behind the housing 20.

[0056] According to an alternative of the invention, the support panel is formed by the protective grid.

[0057] The motor vehicle can, for example, be a private motor vehicle or a commercial motor vehicle.

[0058] Figure 2 shows an exploded view of a vehicle bumper assembly automobile. The motor vehicle may correspond to the one shown in relation to [Fig.1].

[0059] The housing 20 is configured to accommodate a detection device 22. The detection device 22 is an electronic device. The detection device 22 includes at least one optical sensor or a radar. The detection device 22 is connected to the driver assistance systems of the motor vehicle 10. The detection device 22 may include a radar module, in particular with a radar.

[0060] According to one variant of the invention, the detection device is a lidar module.

[0061] According to one variant of the invention, the detection device is a camera.

[0062] The detection device 22 is behind the protective grille 24. The detection device 22 is in the opening 26. The opening 26 is closed by an outer screen 28. The outer screen 28 is in front of the detection device 22. The outer screen 28 is permeable to the signals emitted and / or collected by the detection device 22. The outer screen 28 is attached to the protective grille 24. The outer screen 28 is a cover that closes the opening 26. The outer screen 28 protects the detection device 22 from weathering and external projections. The outer screen 28 is adjacent to the housing 20. It comprises, for example, a dielectric material.

[0063] Figure 3 shows a portion of a support panel 18 comprising a detection device 22 for a motor vehicle. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 2. The protective grille is not shown for clarity.

[0064] The support panel 18 comprises a front surface 38. The housing 20 is in the front surface 38.

[0065] The housing 20 includes a longitudinal edge 36. The longitudinal edge 36 is in the support panel 18. The longitudinal edge 36 surrounds the housing 20. The housing 20 forms a cavity in the support panel 18. The housing 20 includes a vertical wall 40 longitudinally at a distance from the front surface 38. The longitudinal edge 36 is longitudinally between the front surface 38 and the vertical wall 40.

[0066] The vertical wall 40 includes one or more interfaces for electrically connecting the detection device 22 to an electronic system and / or to an on-board computer of the motor vehicle. In this case, the vertical wall 40 is a rear wall.

[0067] The detection device 22 is fixed in the housing 20 by at least one retaining hook 30. The retaining hook(s) 30 are integral with the support panel 18. The retaining hooks 30 protrude from the housing 20 onto the support panel 18. Preferably, the retaining hooks 30 protrude longitudinally from the vertical wall 40. The retaining hooks 30 overlap longitudinally, or extend from the longitudinal edge 36. The vertical wall 40 is longitudinally opposite the at least one retaining hook 30.

[0068] The retaining hooks 30 are upper hooks 32. The support panel 18 further includes lower hooks 34. The detection device 22 includes guide means 72. The retaining hooks 30 are configured to interact with the guide means 72. The retaining hooks 30 longitudinally fix the detection device 22 in a holding position, said holding position allowing the detection device 22 to be implemented during the use of the motor vehicle.

[0069] The detection device 22 can be implemented within the framework of driver assistance or automatic driving functions. It is then essential that the holding position be precisely defined in accordance with the calibration of the detection device 22. The support panel 18 also includes bracing means 44. The bracing means 44 may, for example, include fins 46 and / or indexing points 48. The bracing means 44 are positioned opposite the retaining hooks 30 with respect to the housing 20. The bracing means 44 interact with guiding means 72 to define the holding position of the detection device 22 by locking said detection device 22 in the vertical and transverse directions, as well as longitudinally towards the rear.

[0070] Figure 4 is a rear view of an exterior screen 28 of a motor vehicle. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 3.

[0071] The outer screen 28 includes a positioning flange 50. The outer screen 28 is generally a plane 52. The positioning flange 50 surrounds the plane 52. It forms a longitudinal rim projecting inwards.

[0072] The outer screen 28 includes locking means 54. The locking means 54 include at least one locking protrusion 56. Preferably, the locking protrusion 56 includes a longitudinal arm 58. The locking means 54 are vertically spaced away from the positioning flange 50.

[0073] According to an alternative of the invention, the outer screen is formed by a protective grid.

[0074] According to a preferred embodiment, the outer screen 28 is made of a plastic or composite material. The plastic material may include a thermoplastic or thermosetting material. According to a preferred embodiment, the plastic material is selected from the group comprising polypropylene, polyamide, polyphthalamide, polyetheretherketone, polyphenylene sulfide, polyamide-imide, polyetherimide, polyarylamide, polyepoxide, unsaturated polyester, vinyl ester, or polyester-vinylester resins. For example, the composite material comprises a matrix of a plastic material as described above with reinforcement. For example, the reinforcement comprises glass or carbon fibers.

[0075] The outer screen 28 comprises at least 10% by weight of recycled plastic material based on the total weight of the plastic material; preferably from 10 to 80% by weight; more preferably from 20 to 60% by weight or from 30 to 40% by weight. The use of recycled plastic material reduces the vehicle's environmental footprint.

[0076] Fig. 5 represents a horizontal cross-sectional view of a motor vehicle bumper assembly at the level of the upper hooks 32. The motor vehicle may correspond to that shown in relation to one of Figures 1 to 4.

[0077] When the detection device 22 is installed in the housing 20, at least one retaining hook 30 is able to move between the retaining position (shown here in solid lines) and an offset position (shown in dashed lines) relative to the retaining position in order to allow the insertion of the detection device 22 into the housing 20. The retaining hook 30 includes an elastic arm 70. The retaining hook 30 is an elastic retaining hook. The retaining hook 30 includes a hook groove 68.

[0078] The retaining hook 30 includes a guide bevel 60. The guide bevel is at the free end of the elastic arm 70. The retaining hook 30 and the guide bevel 60 are configured such that when the detection device 22 is inserted into the housing 20, the detection device 22 pushes the guide bevel 60 into the hook groove 68 in order to shift the retaining hook 30 from its holding position to the shifted position. Once the detection device 22 is positioned in its final location against the shims, the guide bevel 60 returns to its initial position.

[0079] The holding position is generally a first position. It is an equilibrium position. The offset position is generally a second position. The offset position is a transitional position. In the offset position, the holding hook 30 opens a passage in the housing 20.

[0080] Once the detection device 22 is placed in the holding position, the outer screen 28 is put in place on the protective grille 24, in front of the opening 26. The protective grille 24 includes a fixing groove 62. The positioning flange 50 is inserted into the fixing groove 62 to fix the outer screen 28 onto the protective grille 24.

[0081] The outer screen 28 is configured so that the locking means 54 are opposite the retaining hook(s) 30, preferably flush with the retaining hook(s) 30. The locking means 54 interact with at least one retaining hook 30. According to an alternative embodiment of the invention, the locking means 54 interact with the upper hooks 32. The locking means 54 are configured to hold at least one retaining hook 30 in the holding position in order to lock the detection device 22 in the housing 20. In particular, it can be seen that the locking means 54 are superimposed on the contour of the retaining hooks 30 in an offset position. Thus, it is understood that the locking means 54 form a lock, a stop against unwanted movement of the retaining hooks 30. Consequently, the detection device 22 can no longer accidentally escape.

[0082] According to an alternative of the invention, the locking means 54 interact with the lower hooks.

[0083] At least one retaining hook 30 is longitudinally positioned between the detection device 22 and the locking means 54. The at least one retaining hook 30 comprises a point 64, and the locking means 54 comprise an internal chamfer 66 adapted to cooperate with the point 64 of the retaining hook 30. The internal chamfer 66 is located on the locking protrusion 56. This allows for easy adjustment of the position of the outer screen 28, and more specifically of the locking means 54, relative to the retaining hooks 30.

[0084] In the holding position, the longitudinal arm 58 of the locking protrusion 56 is directed towards the hook groove 68. The locking protrusion 56 secures the tip 64 in the holding position. The tip 64 can no longer pivot in the hook groove 68, and the retaining hook 30 is locked in the holding position. The longitudinal arm 58 extends along the guide bevel 60. The locking protrusion 56 is longitudinally offset from the housing 20. The retaining hook 30 can no longer move from the holding position to the offset position. The detection device 22 is held firmly in the holding position, even in the event of a slight impact that might deform the support panel or eject the detection device 22.

[0085] Preferably, the blocking protrusion 56 is a blocking rib. It forms a longitudinal blocking finger.

[0086] According to an alternative of the invention, the locking means comprise a cavity; the retaining hook extending into said cavity.

[0087] According to an alternative of the invention, the blocking means include adhesive glued to a free end of the retaining hook.

[0088] According to an alternative of the invention, the support panel includes a single retaining hook, the detection device further comprising a fixing arm inserted into a fixing hole arranged in the housing.

[0089] Figure 6 shows a diagram of a method for assembling a bumper assembly for a motor vehicle. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 5. The bumper assembly corresponds to one of the preceding figures.

[0090] The assembly process comprises the following steps:

[0091] a) supply or manufacture 100 of a support panel with a housing and at least one retaining hook, preferably two retaining hooks;

[0092] b) insertion 102 of the detection device into the housing by pushing the retaining hook towards the offset position and

[0093] c) fixing 104 of the detection device in the housing by the retaining hook 30 in the holding position;

[0094] d) Installation 106 of an external screen 28 facing the support panel. The fixing flange is inserted into the fixing groove of the protective grille. The locking means slide longitudinally along the retaining hooks.

[0095] In step b) insertion 102, the detection device may be connected to an on-board computer. During this step, the detection device, more specifically the guiding means, pushes the guide bevel into the hook groove in order to transiently shift the retaining hook from the holding position to the shifted position. When the detection device reaches its final position, the guiding means interact with the locking means, and the detection device is locked in the vertical, transverse, and longitudinal rearward directions.

[0096] Step c) fastening 104 is carried out by returning at least one retaining hook to the holding position. The detection device is fixed in the longitudinal direction, towards the front.

[0097] Step d) installation 106 includes arranging the outer screen in front of the detection device and adjacent to the housing.

[0098] Step d) Installation 106 further includes a substep 108 for locking at least one retaining hook in the holding position by positioning locking means opposite at least one retaining hook. The locking means are located at the level of the retaining hooks so as to be able to lock them in case of displacement. The locking protrusions make contact via their internal chamfer with the tip of the corresponding retaining hook. This allows precise adjustment of the position of the outer screen in front of the protective device, and more specifically of the locking protrusions in front of the corresponding hook grooves.

[0099] The invention comprises the combination of all the embodiments illustrated by all the figures.

[0100] Figures 2 to 5 are isometric views. They each respect a specific scale, real angles and real proportions.

Claims

Demands

1. Assembly for motor vehicle bumper (10), the assembly comprising a support panel (18) with a housing (20), at least one retaining hook (30); the assembly further comprising a detection device (22) in the housing (20) and held by the at least one retaining hook (30); an outer screen (28) adjacent to the housing (20); the at least one retaining hook (30) being capable of moving between a retaining position of the detection device (22) in the housing (20), and a position offset from the retaining position in order to allow the insertion of the detection device (22) into the housing (20); characterized in that the outer screen (28) comprises locking means (54) configured to hold the at least one retaining hook (30) in the retaining position in order to lock the detection device (22) in the housing (20).

2. Assembly according to claim 1, characterized in that the blocking means (54) comprise at least one blocking protrusion (56), preferably, the at least one blocking protrusion (56) comprises a longitudinal arm (58). Preferably, the at least one retaining hook (30) is located between the detection device (22) and the blocking means (54).

3. Assembly according to any one of claims 1 to 2, characterized in that the blocking means (54) extend longitudinally along the detection device (22); preferably, the detection device (22) is a radar module.

4. An assembly according to any one of claims 1 to 3, characterized in that at least one retaining hook (30) comprises a guide bevel (60); the assembly is configured such that upon insertion of the detection device (22) into the housing (20), the detection device (22) pushes the guide bevel (60) to offset the retaining hook (30) from the retaining position to the offset position; the locking means (54) extending along the guide bevel (60). Preferably, at least one retaining hook (30) protrudes from the housing (20) onto the support panel (18).

5. Assembly according to any one of claims 1 to 4, characterized in that the outer screen (28) is a cover covering the housing (20), and the support panel (18) forms a bumper skin (16).

6. Assembly according to any one of claims 1 to 5, characterized in that at least one retaining hook (30) comprises a point (64), the locking means (54) comprise an internal chamfer (66) adapted to cooperate with the point (64) of the retaining hook (30).

7. Assembly according to any one of claims 1 to 6, characterized in that the locking means (54) are longitudinally at a distance from the housing (20); preferably, the housing (20) comprises a vertical wall (40) longitudinally opposite at least one retaining hook (30).

8. Assembly according to any one of claims 1 to 7, characterized in that the assembly comprises an air inlet protective grille (24), said protective grille (24) being mounted on the support panel (18) and having an opening (26) surrounding the housing (20), the outer screen (28) being attached to the protective grille (24).

9. Motor vehicle (10) comprising a bumper with an assembly, characterized in that the assembly conforms to any one of claims 1 to 8; preferably, the bumper is a front bumper, and the assembly includes a piloted air intake module behind the housing.

10. Method for assembling a motor vehicle bumper assembly (10), the assembly method comprising the following steps: • a) supplying or producing (100) a support panel (18) with a housing (20) and at least one retaining hook (30) movable between a holding position and an offset position; • b) inserting (102) a detection device (22) into the housing (20) by pushing the retaining hook towards the offset position; • c) securing (104) the detection device (22) in the housing by the retaining hook (30) in the holding position; • d) installing (106) an outer screen (28) opposite the support panel; characterized in that the outer screen includes blocking means; • Step d) setup (106) further includes a substep of locking (108) at least one retaining hook (30) in the holding position by positioning the locking means (54) at the level of at least one retaining hook (30) in order to lock it.

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