WO2019141796A1

WO2019141796A1 - Aircraft assembly comprising a cap for covering a fastener

Info

Publication number: WO2019141796A1
Application number: PCT/EP2019/051207
Authority: WO
Inventors: Fabrice TRISTANT; François DAILLIEZ
Original assignee: Dassault Aviation
Priority date: 2018-01-18
Filing date: 2019-01-18
Publication date: 2019-07-25
Also published as: FR3076815A1; FR3076815B1

Abstract

The aircraft assembly (10A) comprises a wall (12), a fastener (14) and a cap (16) for covering the fastener (14); the fastener (14) includes a rod (20) and a nut (22), the rod (20) extending along a longitudinal axis (X); the cap (16) defines a cavity (46) which is filled with a sealing material (54) and inside which the fastener (14) is received. The assembly further comprises a member (18) for retaining the cap (16) on the fastener (14), the retaining member (18) being mounted on the fastener (14) and comprising a retaining portion (58), the projection of the retaining portion (58) onto the longitudinal axis (X) partially overlapping the projection of the nut (22) onto the longitudinal axis (X) or extending beyond the projection of the nut (22) onto the longitudinal axis (X) opposite the wall (12).

Description

Aircraft assembly comprising a cover cap of a fastener

The present invention relates to an aircraft assembly comprising a wall, a fastener inserted through the wall, and a cap covering the fastener; the fastener comprising a shank and a nut attached to the shank, the shank extending along a longitudinal axis and being partially inserted into the wall, the nut and the shank projecting from an inner surface of the wall; the cap defining a cavity, the cavity defining a sealing chamber opening on the inner surface of the wall and filled with a sealing material; and the cap being attached against the inner surface of the wall, the fastener being received in the cavity.

Such an assembly is particularly intended for fixing a wall of an aircraft comprising one or more panels, typically two, applied one on the other or a panel applied to a substructure.

Current aircraft must ensure that there is no sparking of the fasteners in the area where the fuel is stored.

In the fuel zones most at risk in terms of lightning, these bodies are subjected to a current of 100 kA. Such a current corresponds in particular to a lightning strike of the aircraft.

A spark generated in the tank could ignite the fuel with catastrophic consequences for the aircraft and the crew.

To avoid the appearance of sparks, it is known to assemble and fix a cap on the fastener projecting from the wall. The cap is filled with a sealing material that secures the cap to the wall and the attachment.

An assembly example of the aforementioned type is described in document WO 2014/184722.

In some cases, due to assembly faults in the factories, aging defects or incidents in service, the cap is detached from the fastener. It is very difficult in practice to ensure the presence of such a cap around the binding over time, which can increase the risk of sparking.

An object of the invention is to provide an assembly to reduce the risk of sparking the fastener simply and inexpensively.

To this end, the subject of the invention is an assembly of the aforementioned type, characterized in that the assembly further comprises a retaining member of the cap for attachment, the retaining member being mounted on the attachment in the cavity, passing through the rod, the retaining member comprising at least one retaining portion disposed away from the inner surface of the wall, the projection of the retaining portion on the longitudinal axis is overlapping at least partially with the projection of the nut on the longitudinal axis, or extending beyond the projection of the nut on the longitudinal axis opposite the wall.

The assembly may include one or more of the following optional features, taken singly or in any technically feasible combination:

the holding part moves transversely beyond the nut;

the retaining member is distinct from the nut;

the retaining member is distinct from the rod;

the retaining member is distinct from the cap;

the cap comprises a body and a partition wall extending from the body of the cap, the body and the partition wall defining the sealing chamber filled with the sealing material and an electrical insulation chamber filled with a fluid , especially filled with air;

the attachment is received in the sealing chamber or in the electrical insulation chamber;

- The electrical insulation chamber surrounds the sealing chamber, outside thereof;

- The retaining member comprises a ring, traversed by the rod of the fastener, the retaining portion extending transversely from the ring;

the ring is disposed along the longitudinal axis between the nut and the inner surface of the wall, or the nut is disposed along the longitudinal axis between the ring and the inner surface; the wall;

the ring is mounted on the fastener, the fastener being received in the sealing chamber, and a portion of the sealing material being arranged, along the longitudinal axis, between the retaining member and the inner surface of the wall;

- The retaining portion comprises a ring protruding and flaring from the ring, the ring advantageously having outer splines;

the retaining portion comprises a finger protruding transversely beyond the nut, a portion of the sealing material being disposed between the finger and the inner surface of the wall;

- The ring is mounted on the attachment, the retaining portion being placed in contact with the cap;

- The cap is overmolded on the retaining portion of the retaining member, the ring being clipped or screwed onto the rod;

- The cap comprises a body and the retaining portion comprises a ring projecting from the ring, the ring and / or the ring delimit on the one hand the sealing chamber filled with the sealing material and secondly, an electrical insulation chamber filled with a fluid, in particular filled with air;

- The ring is disposed above the nut, said ring being in contact with the inner surface of the wall;

the ring and the ring delimit externally with the body of the cap the sealing chamber filled with the sealing material, the ring and the ring defining the electrical insulation chamber;

the ring is disposed below the nut, the ring defining the electrical insulation chamber;

one of the retaining part and the body comprises at least one radial projection extending from the ring, the other of the retaining part and the body comprising a complementary boss or defining a complementary groove cooperating with the radial projection, the complementary boss being disposed along the longitudinal axis, between said radial projection and the inner surface of the wall;

the cap has a body made of the same material as the sealing material;

the cap has a body made of a material different from the sealing material;

the retaining portion comprises a finger protruding transversely beyond the nut, a portion of the sealing material being disposed between the finger and the inner surface of the wall, the retaining member comprising at least one other finger structurally identical, the fingers being regularly distributed angularly about the longitudinal axis;

- The retaining member has a number of fingers greater than or equal to three;

a bead of sealing material is disposed outside the cavity around the body of the cap, and is attached against the inner surface of the wall and against the body;

- The ring further comprises a plurality of other projections in contact with the complementary boss, the complementary boss of the body being disposed along the longitudinal axis, between said other projection of the ring and the inner surface of the wall;

- The projections of the crown are distributed regularly angularly about the longitudinal axis;

the body has an open bell shape defining an opening opening on the wall whose free edge is in contact with the inner surface of the wall, the fastener passing through the opening, the body being devoid of an injection orifice of the sealing material distinct from the opening;

- The attachment comprises an additional washer interposed between the nut and the inner surface of the wall, the additional washer being separate from the retaining member;

the sealing material is made of mastic;

the wall is a wall of an aircraft.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

- Figure 1 is a schematic sectional view along a median axial plane of a first assembly according to the invention;

- Figure 2 is a schematic top view of the retaining member of the first assembly of Figure 1;

FIG. 3 is a schematic view of an aircraft comprising the first assembly of FIG. 1;

FIG. 4 is a view similar to FIG. 1 of a second assembly according to the invention;

- Figure 5 is a schematic perspective view of the retaining member of the second assembly of Figure 4;

FIGS. 6 to 11 are respectively views similar to FIG. 1 of a third, a fourth, a fifth, a sixth, a seventh and an eighth assembly according to the invention; ;

- Figure 12 is a schematic perspective view of the retaining member of the eighth assembly of Figure 1 1;

FIG. 13 is a view similar to FIG. 1 of a ninth assembly according to the invention, and

- Figures 14 and 15 are respectively schematic views from above and in section of the retaining member of the ninth assembly of Figure 13;

A first assembly 10A according to the invention is illustrated in FIGS. 1 and 2.

The first assembly 10A comprises a wall 12, a fastener 14 inserted through the wall 12, and a cap 16 covering the fastener 14.

The first assembly 10A further comprises a retaining member 18 of the cap 16 to the fastener 14. The wall 12 comprises a first portion 12A (here a first panel) and a second portion 12B (here a second panel) maintained on the first portion 12A via the fastener 14.

Each portion 12A, 12B is for example made of aluminum or carbon, with or without glass fold in the case of carbon.

The wall 12 is typically a wall of an aircraft 13, shown in Figure 3. The wall 12 is for example an aircraft panel.

It delimits in particular a fuel storage zone, such as the zone 2A of the aircraft 13, shown in FIG. 3. The zone 2A extends at least between the fuselage 13A and the wings 13B of the aircraft 13 on a band of width of the order of 500 mm. This fuel zone is particularly sensitive to the risk of lightning as lightning in this area 2A can attach directly to the head 32 of the fastener 14.

The wall 12 defines a receiving hole 24 of the fastener 14 extending along a longitudinal axis X.

The fastener 14 is mounted in the hole 24 through the wall 12.

It comprises at least one rod 20 and a nut 22 fixed to the rod 20. FIGS. 1, 4, 6 to 11 and 13 are partial sectional views, in which the nut 22 has not been cut for reasons for clarity.

The rod 20 is for example made of titanium or steel. In addition, it is coated or not with a layer of paint. The material of the selected rod 20 and the associated paint may change the flow of current between the head 32 of the fastener 14 and the portions 12A and 12B.

It extends along a longitudinal axis X and is partially inserted into the wall 12. Thereafter, the terms "longitudinal", "transverse", and "radial" will be understood with reference to the longitudinal axis X.

The rod 20 is thus received in the receiving hole 24 of the fastener 14 defined through the portions 12A, 12B of the wall 12.

The rod 20 protrudes from an inner surface 26 of the wall 12.

It has a threaded region 28, in particular on its portion protruding from the inner surface 26.

The rod 20 comprises a stem body 30 and a head 32.

The stem body 30 extends from the head 32 along the longitudinal axis X.

As illustrated in FIG. 1, the rod body 30 defines the threaded region 28 in the vicinity of its free end 34 and a threadless region 35 disposed between the threaded region 28 and the head 32. The stem body 30 has a diameter maximum. The maximum diameter is for example the diameter of the threadless region 35.

The threadless region 35 has a cylindrical shape of revolution about the longitudinal axis X.

The head 32 of the rod 20 has a frustoconical shape.

She came from matter with the stem body 30.

The nut 22 is fixed by being screwed onto the threaded region 28 of the rod 20.

The nut 22 is disposed away from the inner surface 26 of the wall 12. It is applied to the retaining member 18. It thus holds the retaining member 18 sandwiched between the inner surface 26 of the wall 12 and the nut 22.

The nut 22 is for example made of titanium or steel.

A portion of the rod 20 protrudes from the nut 22 opposite the inner surface 26 of the wall 12.

The hole 24 is for example devoid of threading.

Here it has a substantially revolution shape around the longitudinal axis X.

Hole 24 has a receiving portion 40 of head 32 of shank 20 and a receiving portion 42 of shank body 30.

The receiving part 40 of the head 32 receives the head 32 of the rod 20 of the fastener 14.

It opens out opposite the nut 22 of the fastener 14.

The receiving part 40 of the head 32 has a truncated cone shape about the longitudinal axis X, complementary to the shape of the head 32 of the rod 20. The truncated cone shape flares out from the part of home 42 of the stem body 30 opposite the nut 22 along the longitudinal axis X.

The receiving portion 42 of the stem body 30 receives the threadless region 35 of the stem body 30. It has a cylindrical shape of revolution about the longitudinal axis X.

The receiving portion 42 of the stem body 30 has a thickness substantially less than the length of the thread-free region 35 of the stem body 30.

As illustrated in Figure 1, the cap 16 is attached against the inner surface 26 of the wall 12 by overlapping the retaining member 18, the projecting portion of the rod 20 and the nut 22. It is here in contact with the inner surface 26.

The cap 16 covers and envelopes the portion of the fastener 14 projecting from the inner surface 26 of the wall 12.

The cap 16 comprises a body 44 in the shape of a bell, defining a cavity

46. The cap 16 defines around its free edge 50 an opening 48 opening on the wall 12 and traversed by the fixing 14. The edge 50 is in this example in contact with the inner surface 26 of the wall 12.

The body 44 is devoid of injection orifice of the sealing material distinct from the opening 48.

The body 44 has a substantially constant thickness, for example between 1 mm and 4 mm.

The cavity 46 delimits a sealing chamber 52 opening on the inner surface 26 of the wall 12 and filled with a sealing material 54. In the example of Figure 1, the cavity 46 corresponds to the sealing chamber 52, and is here filled with the sealing material 54.

The sealing material 54 is capable of passing from a non-solid state to a solid state.

It is here solid and adheres to the body 44 of the cap 16.

The sealing material is electrically insulating.

The sealing material 54 is, for example, putty, in particular putty marketed under the reference PR 1440.

The body 44 of the cap 16 is for example made of the same material as the sealing material 54. In a variant, the body 44 of the cap 16 is made of a material different from the sealing material.

The attachment 14 is received in the cavity 46 and thus here in the sealing chamber 52. In particular, the nut 22 and the entire portion of the rod 20 projecting from the wall 12 are received in the sealing chamber 52 .

The sealing material 54 adheres to the fastener 14. It drowns the nut 22, the entire portion of the rod 20 protruding from the wall 12 and the retaining member 18 in the sealing chamber 52.

The sealing chamber 52 forms a sparkle confinement zone capable of being generated by a lightning strike on the fixing head 32.

The retaining member 18 adds a dedicated mechanical holding element of the cap 16 to the attachment 14 and to the wall 12.

It is disposed in the cavity 46, in particular here in the sealing chamber 52.

The retaining member 18 is distinct from the nut 22. By the expression "a first distinct element of a second element" is meant that the first element is not integral with the second element.

The retaining member 18 is also distinct from the cap 16. The retaining member 18 is traversed by the rod 20.

The retaining member 18 is thus distinct from the rod 20.

The retaining member 18 is made of metal or a composite material, for example conductive or insulating. It is coated or not with a coat of paint. The material in which the retaining member 18 is made and the associated paint may change the flow of currents.

If the paint and the material in which the retaining member 18 is made are insulating, the assembly is more robust to the confinement of the sparks independently of the embodiment of the retaining member 18.

It comprises a ring 56, traversed by the rod 20 of the fastener 14, and at least one retaining portion 58 extending transversely from the ring 56.

In the first assembly 10A, the ring 56 is disposed longitudinally between the nut 22 and the inner surface 26 of the wall 12.

It is mounted on the fastener 14. The ring 56 is held in the fastener 14 by being locked by the nut 22. In particular, it is here in contact with the nut 22 and the inner surface 26 of the wall 12 .

The ring 56 defines a bore 60 traversed by the rod 20. The diameter of the bore 60 is for example substantially equal to the diameter of the rod 20.

The ring 56 is substantially flat, and extends transversely to the longitudinal axis X.

It has a thickness advantageously between 0.5 mm and 2 mm.

In one embodiment, the thickness of the ring 56 is constant. Alternatively, the thickness of the ring 56 is variable.

The ring 56 is here projecting radially with respect to the nut 22.

In the first assembly 10A, the retaining portion 58 comprises a ring 62 projecting and flaring from the ring 56.

The ring 62 and the ring 56 are preferably integral.

The ring 62 of the holding portion 58 is disposed away from the inner surface 26 of the wall 12, in particular at a distance from the wall 12 longitudinally.

It deviates radially beyond the nut 22. In particular, the ring 62 is transversely projecting relative to the nut 22.

In the example illustrated in Figure 1, the projection of the retaining portion 58 on the longitudinal axis X is superimposed at least partially with the projection of the nut 22 on the longitudinal axis X.

The ring 62 flares radially away from the axis X, opposite the wall 12.

It is preferably devoid of contact with the body 44 of the cap 16. A portion of the nut 22 projects longitudinally beyond the ring 62, away from the inner surface 26. The height along the longitudinal axis X between the inner surface 26 of the wall 12 and the point of the crown 62 farthest from said inner surface 26 is less than the height along the longitudinal axis X between the inner surface 26 of the wall 12 and the point of the nut 22 furthest from said inner surface 26.

In addition, the nut 22 and the ring 62 delimit between them an annular space 63.

The difference in height between the nut 22 and the ring 62, and the annular space 63 between them allow the mounting of a clamping tool around the nut 22, including when the nut 22 is in contact with the nut. ring 56 of the retaining member 18.

The nut 22 is thus adapted to be screwed onto the rod 20 by a clamping tool until it comes into contact with the ring 56.

As illustrated in FIG. 1, a portion of the sealing material 54 is disposed along the longitudinal axis X between the ring 62 of the retaining portion 58 and the inner surface 26 of the wall 12.

Similarly, a part of the sealing material 54 is disposed in the annular space 63 and longitudinally on the free edge of the ring 62.

The sealing material 54 thus adheres to the ring gear 62.

As illustrated in Figure 2, the ring 62 here has outer splines 64. The outer splines 64 extend longitudinally.

The outer splines 64 are adapted to allow the passage of the sealing material 54 until the material comes into contact with the inner surface 26 of the wall 12.

The ring 62 defines for example a plurality of through holes not shown. The through holes are adapted to facilitate the passage of the sealing material.

In a variant not shown, the body 44 of the cap defines a through hole, preferably aligned along the axis X. The through hole of the body 44 is adapted to allow the exit of a surplus of sealing material, after creep of the material of sealing in the cavity 46 when positioning the cap on the attachment 14, and demonstrate that the necessary amount has been used.

Alternatively (not shown) the attachment 14 comprises an additional washer interposed between the nut 22 and the inner surface 26 of the wall 12, for example interposed between the nut 22 and the ring 56, the additional washer being separate from the retainer 18.

The ring 56 is then in contact with the nut 22 and the additional washer or in contact with the additional washer and the inner surface 26 of the wall 12. A method of mounting the first assembly 10A will now be described.

The mounting method comprises providing the portions 12A, 12B of the wall 12, the attachment 14 and the retaining member 18.

Initially, the nut 22 of the fastener 14 and the retaining member 18 are away from the rod 20 of the fastener 14.

The rod 20 is inserted into the hole 24 of the wall 12 until the head 32 of the rod 20 is in contact with the receiving portion 40 of the head 32 of the hole 24.

The retaining member 18 is then engaged on the rod 20 and placed in abutment on the inner surface 26 of the wall 12.

The nut 22 is subsequently mounted on the rod 20 by being screwed by a clamping tool. Due to the difference in height between the nut 22 and the ring gear 62, and thanks to the annular space 63 present between the nut 22 and the ring gear 62, the nut 22 is screwed until it comes into contact with the ring 56.

The cap 16, initially disposed away from the inner surface 26 of the wall 12, is then filled with sealing material 54. The sealing material 54 is contained in the sealing chamber 52 of the cap 16 in fluid form.

The cap 16 containing the sealing material 54 is turned over and is brought closer to the fastener 14 until the free edge 50 comes into contact with the inner surface 26 of the wall 12.

During this approach, the sealing material 54 flows around the fastener 14 and makes contact with the inner surface 26 of the wall 12. The sealing material 54 passes through the outer splines 64 of the ring 62 until a portion of the sealing material 54 is disposed between the ring gear 62 and the inner surface 26 of the wall 12.

Optionally, a whitewash of sealing material is made to guarantee the presence of sealing material 54 at the periphery of the opening 48.

The process then comprises a step of solidification of the sealing material 54.

At the end of this step, the sealing material 54 is solid. It adheres to the body 44 of the cap 16, to the inner surface 26 of the wall 12, to the attachment 14 and to the retaining portion 58 of the retaining member 18.

In use, the retaining member 18 thus provides a large mechanical gripping surface of the sealing material 54 capable of preventing the removal of the cap 16 away from the fastener 14. This mechanical gripping surface is in the first place an additional surface on which the sealing material 54 adheres, which improves the retention of the cap 16 at the fastener 14.

In addition, this surface also prevents longitudinal displacement of the sealing material 54 away from the inner surface 26 of the wall 12.

Indeed, in the case where a force directed along the longitudinal axis X opposite the inner surface 26 of the wall 12 is applied against the cap 16, the portion of the sealing material 54 disposed between the retaining portion 58 and the inner surface 26 of the wall 12 abuts against the retaining portion 58. Since the body 44 of the cap 16 adheres to the sealing material 54, the retaining portion 58 prevents the removal of the body 44 from the cap 16 to the distance from fixation 14.

A second assembly 10B according to the invention is illustrated in FIGS. 4 and 5.

This second assembly 10B differs from the first assembly 10A in that the retaining portion 58 is devoid of crown. The retaining portion 58 comprises at least one finger 66 protruding transversely beyond the nut 22.

As illustrated in Figures 4 and 5, the retaining member 18 further comprises a plurality of other structurally identical fingers 66.

The retaining member 18 comprises, in the example illustrated in Figure 5, a number of fingers 66 equal to four. Alternatively, the retaining member 18 comprises a number of fingers 66 greater than or less than four, in particular greater than or equal to three.

Each finger 66 extends from the ring 56, away from the wall 12, away from the longitudinal axis X.

It has in particular a curved shape forming a hollow 67 opposite the wall 12.

Each finger 66 is in this example in contact with the cap 16 at its free end 68. This free end 68 then matches the shape of the body 44 of the cap 16.

A part of the sealing material 54 is disposed between each finger 66 and the inner surface 26 of the wall 12. This part of material is in particular arranged in the hollow 67.

Each finger 66 and the ring 56 are preferably integral.

The fingers 66 are here regularly distributed angularly around the longitudinal axis X. The spacing between two successive fingers 66 is adapted to allow the passage of the sealing material 54 until the material comes into contact with the inner surface 26 of the wall 12.

In use, each finger 66 provides an additional surface on which the sealing material 54 adheres, which adds a mechanical strength zone of the cap 16 to the fastener 14.

In addition, as in the first assembly, the recess 67 of each finger 66 also prevents longitudinal displacement of the sealing material 54 away from the inner surface 26 of the wall 12.

A third assembly 10C according to the invention is illustrated in FIG.

This third assembly 10C differs from the first assembly 10A in that the nut 22 is disposed, along the longitudinal axis X, between the retaining member 18 and the inner surface 26 of the wall 12.

In particular, the nut 22 is disposed, along the longitudinal axis X, between the ring 56 and the inner surface 26 of the wall 12.

As before, the ring 56 defines a bore 60 through which the rod 20 passes.

The threaded region 28 of the rod 20 extends here beyond the nut 22.

In a first embodiment of the third assembly 10C, the edges of the bore 60 are threaded and cooperate with the threaded region 28 of the rod 20 to fix the ring 56 with respect to the rod 20.

The ring 56 is here represented in contact with the nut 22.

A portion of the rod 20 of the attachment 14 protrudes from the ring 56, opposite the inner surface 26 of the wall 12.

The retaining portion 58 is formed by the peripheral region 70 projecting from the ring 56, which projects radially with respect to the nut 22.

The peripheral region 70 here extends radially in the extension of the central part of the ring 56, transversely to the longitudinal axis X.

It has a thickness substantially equal to the thickness of the central portion of the ring 56.

The peripheral region 70 extends angularly over the entire periphery of the ring 56.

The peripheral region 70 is integral with the ring 56.

In this third assembly, the projection of the retaining portion 58 on the longitudinal axis X thus extends beyond the projection of the nut 22 on the longitudinal axis X opposite the wall 12. The peripheral region 70 projects radially beyond the nut 22 over a radial distance relative to the nut 22, the radial distance being for example greater than 1 mm, and preferably greater than 5 mm.

Part of the sealing material 54 is disposed between the peripheral region 70 and the inner surface 26 of the wall 12.

Thus, a portion of the sealing material 54 is disposed longitudinally on either side of the peripheral region 70.

As in the first assembly 10A, the retaining member 18 thus provides a mechanical attachment surface to the sealing material 54 able to prevent removal of the cap 16 away from the fastener 14.

The peripheral region 70 is here radially away from the body 44 of the cap 16.

The radial spacing between the peripheral region 70 and the body 44 of the cap 16 is adapted to allow the passage of the sealing material 54 so that a portion of the sealing material 54 is disposed between the peripheral region 70 and the inner surface 26. .

In use, the peripheral region 70 provides an additional surface on which the sealing material 54 adheres, which improves the retention of the cap 16 at the attachment 14. In addition, the peripheral region 70 also prevents longitudinal displacement of the sealing material 54 away from the inner surface 26 of the wall 12.

In a variant not shown of this third assembly 10C, the edges of the bore 60 are threadless. The ring 56 is then mounted by being clipped on the rod 20. For example, one of the ring 56 and the rod 20 then comprises at least one clipping projection received in a recess complementary to the arranged clipping projection in the other of the ring 56 and the rod 20.

In another variant (not shown), the ring 56 is disposed longitudinally away from the nut 22 and is free of contact with the nut 22. A portion of the sealing material 54 is then disposed between the ring 56 and the nut 22.

A fourth assembly 10D is illustrated in FIG.

This fourth assembly 10D differs from the third assembly 10C in that the retaining portion 58 comprises a ring 62 extending from the outer edge of the peripheral region 70.

The ring 62 flares out from the peripheral region 70 towards the wall 12.

It has an edge 72 extending facing the inner surface 26 of the wall 12. The edge 72 is disposed at a distance from said inner surface 26. The ring 62, the nut 22 and the peripheral region 70 delimit an annular receiving space 74, facing the wall 12, in which a portion of the sealing material 54 is received.

The ring 62 is here placed radially away from the body 44 of the cap 16.

The radial spacing between the ring 62 and the body 44 of the cap 16 is adapted to allow the passage of the sealing material 54 so that a portion of the sealing material 54 is disposed in the annular receiving space 74.

In use, the ring 62 and the peripheral region 70 provide an additional surface on which the sealing material 54 adheres. This improves the retention of the cap 16 at the attachment 14. In addition, the receiving space 74 also prevents longitudinal displacement of the sealing material 54 away from the inner surface 26 of the wall 12.

A fifth assembly 10E is illustrated in FIG.

This fifth assembly 10E differs from the third assembly 10C in that the cap 16 is overmolded on the retaining member 18.

In particular, the body 44 of the cap 16 is overmolded on the peripheral region 70 forming the retaining portion 58.

The holding portion 58 is thus in contact with the cap 16.

The retaining member 18 is in contact with the body 44 of the cap 16 and with the attachment 14. It is retained by an annular flange 75A formed in the body 44 of the cap 16. It rests on a step 75B formed in the cap partially closing a central receiving hole of the free end of the rod.

Alternatively, any other holding solution between the retaining member 18 and the body 44 of the cap 16 may be considered.

In this example, the ring 56 is disposed longitudinally away from the nut 22 and free from contact with the nut 22. A portion of the sealing material 54 is then disposed between the ring 56 and the nut 22 .

A method of mounting this fifth assembly 10E will now be described.

This mounting method differs from the assembly method of the third assembly 10C in that the cap 16, receiving the ring 56 of the retaining member 18, is screwed or clipped onto the fastener 14 by engaging the free end 34 of the rod 20 in the bore 60 of the ring 56.

During screwing or clipping of the cap 16, the sealing material 54 flows around the fastener 14 until it comes into contact with the inner surface 26 of the wall 12, and then solidifies, as previously described. The sealing material 54 then adheres to the body 44 of the cap 16, to the inner surface 26 of the wall 12 and to the fastener 14.

The body 44 of the cap 16 is thus fixed to the attachment 14 by means of the retaining member 18.

In use, in the case where a force directed along the longitudinal axis X opposite the inner surface 26 of the wall 12 is applied against the cap 16, the retaining member 18 remains held against the fastener 14. This thus prevents the removal of the body 44 of the cap 16 away from the attachment 14, since the body 44 of the cap 16 is overmolded on the retaining member 18.

A sixth assembly 10F is illustrated in FIG. 9.

This sixth assembly 10F differs from the fifth assembly 10E in that the cap 16 comprises a partition wall 76 extending from the body 44 of the cap 16 to the outside of the body 44 of the cap 16.

The cavity 46 then has an electrical insulation chamber 78 filled with a fluid 80 and the sealing chamber 52 filled with sealing material 54.

The fluid 80 is in particular air.

In the example illustrated in FIG. 9, the sealing chamber 52 is defined by an inner surface 82 of the body 44 of the cap 16. The sealing chamber 52 forms a first sparkling confinement zone capable of being generated by a lightning impact on the fixing head 32.

In addition, the electrical insulation chamber 78 is defined in this example by the partition wall 76 and an inner surface 26 of the body 44.

The electrical isolation chamber 78 surrounds the sealing chamber 52, outside thereof.

The electrical insulation chamber 78 surrounds in particular the sealing chamber 52 over its entire periphery, outside thereof.

The fastener 14 is here received in the sealing chamber 52.

In this example, the separation wall 12 and the body 44 of the cap 16 are disposed away from the inner surface 26 of the wall 12.

A portion of the sealing material 54 overflows into the electrical insulation chamber 78 beyond the body 44 of the cap 16.

The assembly further comprises a bead 84 of sealing material 54 disposed outside the cavity 46 around the cap 16, in particular around the partition wall 76 and in contact with the inner surface 26 of the wall 12.

The cord 84 is attached against the inner surface 26 of the wall 12 and against an inner surface 26 of the partition wall 76. In use, after a lightning strike on the fixing head 32, the electrical insulation chamber 78 forms a second sparkle confinement zone capable of being generated by a lightning strike on the fixing head 32. More specifically, the electrical insulation chamber 78 contains possible spark that would have managed to pass through the sealing material 54 contained in the cavity 46.

A seventh assembly 10G is illustrated in FIG.

This seventh assembly 10G differs from the sixth assembly 10F in that the electrical isolation chamber 78 is defined by the inner surface 82 of the body 44 of the cap 16, and the sealing chamber 52 is defined by the partition wall 76 and the surface Inner 26 of the body 44.

The fastener 14 is received in the electrical insulation chamber 78.

The sealing chamber 52 surrounds the electrical insulation chamber 78.

An eighth assembly 10H is illustrated in FIGS. 11 and 12.

This eighth assembly 10H differs from the fourth assembly 10D in that the body 44 of the cap 16 is clipped onto the retaining member 18.

The retaining portion 58 thus comprises at least one radial projection 86 extending from the ring 62 opposite the nut 22 towards the body 44 of the cap 16.

In the example of Figures 1 1 and 12, the retaining portion 58 further comprises at least one other radial projection 86 similar. It comprises a number of radial projections 86 preferably between 3 and 8. Alternatively, the number of radial projections 86 greater than 8.

The radial projections 86 are distributed regularly angularly about the longitudinal axis X.

The spacing between two successive radial protrusions 86 is adapted to allow the passage of the sealing material 54 until the material comes into contact with the inner surface 26 of the wall 12.

Each radial projection 86 is in contact with an inner surface 82 of the body 44.

The body 44 of the cap 16 further comprises a plurality of complementary bosses 88 cooperating with each radial projection 86.

The body 44 preferably comprises a number of complementary bosses 88 equal to the number of radial projections 86, each radial projection 86 cooperating respectively with one of the complementary bosses 88.

The complementary bosses 88 are spaced apart from each other. This gap is adapted to allow the passage of the sealing material 54 until the material comes into contact with the inner surface 26 of the wall 12. Each complementary boss 88 extends from the inner surface 82 of the body 44 to the nut 22.

Each complementary boss 88 is disposed between a radial projection 86 and the inner surface 26 of the wall 12. Each complementary boss 88 is advantageously in contact with the radial projection 86 with which it cooperates.

The complementary boss 88 has a thickness, taken parallel to the axis X, substantially equal to the thickness of each radial projection 86.

The ring 62 surrounds the nut 22 and has, in this example, a free edge 72 placed in contact with the inner surface 26 of the wall 12.

In the eighth assembly 10H, the ring 62, the attachment 14, the inner surface 26 of the wall 12 and the peripheral region 70 of the holding portion 58 define an electrical insulation chamber 78 filled with a fluid 80.

The ring 62 and the inner surface 82 of the body 44 of the cap 16 further define the sealing chamber 52.

The fluid 80 is in particular air.

The fastener 14 is thus received in the electrical insulation chamber 78. A portion of the rod 20 passes through the electrical insulation chamber 78, beyond the retaining member 18, and is received in the sealing chamber 52. .

The eighth assembly 10H further comprises a bead 84 of sealing material 54 disposed outside the cavity 46 around the cap 16 and in contact with the inner surface 26 of the wall 12.

During the process of mounting this eighth assembly 10H and supplying the wall 12 and the fastener 14, the retaining member 18 is mounted on the fastener 14, the ring 62 being brought into contact with the inner surface 26 of the wall 12.

The cap 16 containing the sealing material 54 is brought close to the fastener 14 until it is brought into contact with the inner surface 26 of the wall 12.

On approaching the cap 16, the sealing material 54 flows around the retaining member 18 until it is applied to the inner surface 26 of the wall 12. In particular, the sealing material 54 passes between the radial projections 86 where the complementary boss is discontinuous.

In addition, a whitewash of sealing material may be coated around the retaining member 18 before the introduction of the cap 16.

In use, in the case where a force directed along the longitudinal axis X opposite the inner surface 26 of the wall 12 is applied against the cap 16, each complementary boss 88 abuts against the radial projections 86 of the 58. This prevents the removal of the body 44 of the cap 16 away from the fastener 14. In a variant of the eighth assembly 10H, the edges 72 of the ring gear 62 are disposed away from the inner surface 26 of the wall 12. A portion of the sealing material 54 projects into the electrical insulation chamber 78.

As a variant of the eighth assembly 10H, the body 44 of the cap 16 comprises at least one radial projection extending towards the nut 22. In addition, the retaining portion 58 comprises a complementary boss cooperating with each radial projection.

A ninth assembly 101 is illustrated in FIGS. 13, 14 and 15.

This ninth assembly 101 differs from the first assembly 10A in that the body 44 of the cap 16 is clipped onto the retaining member 18.

The retaining portion 58 thus comprises at least one radial projection 86 extending opposite the nut 22 towards the body 44 of the cap 16.

In the example of Figure 14, the retaining portion 58 comprises six radial projections 86. Alternatively, it comprises a number of radial projections 86 greater than six or less than six.

As illustrated in FIG. 13, the body 44 of the cap 16 defines a complementary groove 90 cooperating with each radial projection 86.

The complementary groove 90 is formed in an inner surface 82 of the body 44 of the cap 16.

Each radial projection 86 is received in the complementary groove 90, in contact with the body 44 of the cap 16.

The complementary groove 90 extends in particular angularly about the longitudinal axis X over the entire periphery of the body 44 of the cap 16.

The ring 62 is disposed away from the inner surface 82 of the body 44 of the cap 16. This gap is adapted to allow the passage of the sealing material 54 until the material comes into contact with the inner surface 26 of the wall 12.

In the ninth assembly 101, the ring 62 further defines with the inner surface 26 of the wall 12, an electrical insulation chamber 78 filled with a fluid 80, especially air.

The ring 62 forms a channel 92 surrounding the rod 20 of the fastener 14, the channel 92 defining the electrical insulation chamber 78. As illustrated in Figures 13 and 15, a section of the channel 92 passing through the longitudinal axis X comprises a bottom 94, the bottom 94 being disposed away from the inner surface 26 of the wall 12 and connected to the ring 56 by a curved partition 96. Said section also comprises a cylindrical partition 98 extending from the bottom 94 towards the inner surface 26 of the wall 12.

The bottom 94, the curved partition 96, the cylindrical partition 98 and the inner surface 26 of the wall 12 delimit said chamber filled with fluid 80.

The thicknesses of the bottom 94, the curved partition 96 and the rectilinear partition 98 are substantially equal.

The embodiments described above can be combined in any technically possible combination.

As a variant of the ninth assembly 101, the ring 62 is devoid of an electrical insulation chamber 78 filled with a fluid 80. In particular, the ring 62 does not form the gutter 92.

In another variant of the ninth assembly 101, the body 44 does not define a complementary groove 90. The body 44 of the cap 16 then comprises a complementary boss cooperating with each radial projection 86, said complementary boss being similar to the complementary boss described in the eighth assembly 10H.

In yet another variant of the ninth assembly 101, the body 44 of the cap 16 has at least one radial projection extending towards the nut 22. In addition, the retaining portion 58 comprises a complementary boss or defines a complementary groove cooperating with each radial projection.

Thanks to the features described above, the attachment of the cap 16 to the wall 12 and the attachment 14 is significantly improved, simply and inexpensively.

The assembly of the invention reduces the risk of sparking the fastener by ensuring the presence of the cap 16 around the fastener 14 over time.

This mechanically secured guarantee improves the robustness of assemblies in the fuel zone vis-à-vis the lightning.

In the embodiment of FIG. 8, as indicated above, the retaining member 18 rests on the step 75B formed in the cap 16.

In particular, the step 75B is formed by at least one tab or a flat ring whose entire thickness protrudes perpendicular to the longitudinal axis X.

The step 75B is disposed longitudinally between the ring 18 and the inner surface 26 of the wall 12. The projection of the step 75B on the longitudinal axis X extends beyond the projection of the nut 22 on the longitudinal axis X opposite the wall 12.

At least one region of the body 44 of the cap 16 is further applied against a first surface of the opposite ring 18, along the longitudinal axis X, to a second surface of the ring 18 which is in contact with the step 75B.

More specifically, as illustrated in FIG. 8, at least one region of the body 44 is both applied to said first surface of the ring opposite the step 75B, to the annular flange 75A and to the second surface of the annular ring. contact with step 75B.

This reduces the bulk of the assembly, and ensures a good distribution of the sealing material inside the cap 16.

This description also applies to the embodiment of FIGS. 9 and 10.

In the embodiment of Figure 9, the attachment of the cap 16 is particularly robust, since the retaining member 18 is in contact with the sealing material 54 in the sealing chamber 52, while providing very good electrical insulation thanks to the presence of the electrical insulation chamber 74 surrounding the sealing chamber 52 on the outside of the latter.

Claims

An aircraft assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) comprising a wall (12), a fastener (14) inserted through the wall (12), and a cap (16). ) covering the fastener (14);

the fastener (14) comprising a rod (20) and a nut (22) attached to the rod (20), the rod (20) extending along a longitudinal axis (X) and being partially inserted into the wall (12) the nut (22) and the rod (20) projecting from an inner surface (26) of the wall (12);

the cap (16) defining a cavity (46), the cavity (46) defining a sealing chamber (52) opening on the inner surface (26) of the wall (12) and filled with a sealing material (54) ;

the cap (16) being attached against the inner surface (26) of the wall (12), the fastener (14) being received in the cavity (46),

characterized in that the assembly further comprises a retaining member (18) of the cap (16) to the fastener (14), the retaining member (18) being mounted on the fastener (14) in the cavity (46). ), through which the rod (20) passes, the retaining member (18) comprising at least one retaining portion (58) disposed away from the inner surface (26) of the wall (12),

the projection of the retaining portion (58) on the longitudinal axis (X) overlapping at least partially with the projection of the nut (22) on the longitudinal axis (X), or extending beyond the projection of the nut (22) on the longitudinal axis (X) opposite the wall (12).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 1, wherein the retaining portion (58) extends transversely beyond the nut (22). ).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of claims 1 or 2, wherein the retaining member (18) is distinct from the nut (22).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of the preceding claims, wherein the cap (16) comprises a body (44) and a partition wall ( 76) extending from the body (44) of the cap (16), the body (44) and the partition wall (76) defining the chamber of seal (52) filled with the sealing material (54) and an electrical insulation chamber (78) filled with a fluid (80), in particular filled with air.

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 4, wherein the fastener (14) is received in the sealing chamber (52) or in the chamber. electrical insulation (78).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 4 or 5, wherein the electrical isolation chamber (78) surrounds the sealing chamber (52) at outside the sealing chamber (52).

7. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of the preceding claims, wherein the retaining member (18) comprises a ring (56), crossed by the rod (20) of the fastener (14), the retaining portion (58) extending transversely from the ring (56).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 7, wherein the ring (56) is disposed along the longitudinal axis (X), between the nut (22) and the inner surface (26) of the wall (12), or wherein the nut (22) is arranged, along the longitudinal axis (X), between the ring (56) ) and the inner surface

(26) of the wall (12).

9. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of claims 7 or 8, wherein the ring (56) is mounted on the fastener (14) the fastener (14) being received in the sealing chamber (52), and a portion of the sealing material (54) being disposed along the longitudinal axis (X) between the retaining member (18) and the inner surface (26) of the wall (12).

10. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 9, wherein the retaining portion (58) comprises a ring (62) protruding and flaring at from the ring (56), the ring (62) advantageously having outer splines (64).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 9, wherein the retaining portion (58) comprises a finger (66) making protruding transversely beyond the nut (22), a portion of the sealing material (54) being disposed between the finger (66) and the inner surface (26) of the wall (12).

12. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of claims 7 to 11, wherein the ring (56) is mounted on the fastener (14). ), the retaining portion (58) being placed in contact with the cap (16).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 12, wherein the cap (16) is overmoulded on the retainer portion (58) of the retainer. (18), the ring (56) being clipped or screwed onto the rod (20).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of claims 7 to 13, wherein the cap (16) comprises a body (44) and the portion retaining means (58) comprises a ring gear (62) projecting from the ring (56), the ring (62) and / or the ring (56) delimiting on the one hand the filled sealing chamber (52) sealing material and secondly, an electrical insulation chamber (78) filled with a fluid (80), in particular filled with air.

15. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 14, wherein the ring (56) is disposed above the nut (22), said crown (62) being in contact with the inner surface (26) of the wall (12).

16. The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 15, wherein the ring (62) and the ring (56) delimit externally with the body (44). from the cap (16) the sealing chamber (52) filled with sealing material (54), the ring gear (62) and the ring (56) defining the electrical isolation chamber (78).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to claim 14, wherein the ring (56) is disposed below the nut (22), the ring (62) defining the electrical isolation chamber (78).

The assembly (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 101) according to any one of claims 14 to 17, wherein one of the retaining portion (58) and the body (44) comprises at least one radial projection (86) extending from the ring (62), the other of the holding portion (58) and the body (44) having a boss complementary (88) or defining a complementary groove (90) cooperating with the radial projection (86), the complementary boss (88) being arranged, along the longitudinal axis (X), between said radial projection (86) and the inner surface (26) of the wall (12).