Detachable blind fastening device, arrangement comprising at least one such fastening device and method for dismantling such a fastening device

Description

[0001] This application relates to a removable blind-type fastening device, to an assembly comprising at least one such fastening device, and to a method for dismantling such a fastening device.

[0002] According to an embodiment visible on the figures 1 to 3 and described in document EP2647851, a blind type fastening device 10, configured to hold together first and second parts 12, 14, comprises a tubular body 16, an expanding nut 18 and a screw 20. The first and second assembled parts 12, 14 each comprise a through hole 12.1, 14.1, to house the tubular body 16, and a bearing surface 12.2, 14.2, the bearing surface 12.2 of the first part 12 comprising a chamfer 12.3 around the through hole 12.1.

[0003] The tubular body 16 comprises a main portion 22 extending between first and second ends 22.1, 22.2, and a detachable portion 24 comprising a lateral face 24.1 with a hexagonal cross-section and a breakable junction zone 26 connecting the main portion 22 and the detachable portion 24. The tubular body 16 includes a through orifice 28 along its entire length, which has a frustoconical diameter reduction 28.1 at the second end 22.2 of the main portion 22. The first end 22.1 of the main portion 22 has a frustoconical shape flared towards the second end 22.2. The tubular body 16 includes, at the second end 22.2 of the main portion 22, a frustoconical head 30 configured to fit into the chamfer 12.3 of the first part 12 in operation.

[0004] The expanding nut 18 extends between the first and second ends 18.1, 18.2, the second end 18.2 cooperating with the first end 22.1 of the main part 22 of the tubular body 16 in operation. The expanding nut 18 comprises a lateral face 32 that is initially smooth, as well as a through hole 34 that connects the first and second ends 18.1, 18.2. The expanding nut 18 can deform and expand to form a bulb 36 (visible in the figures 2 and 3 ) bearing against the bearing surface 14.2 of the second part 14 when the expanding nut 18 is subjected to a compressive force between its first and second ends 18.1, 18.2.

[0005] The through hole 34 has a threaded section 34.2 near the first end 18.1 of the expanding nut 18.

[0006] The screw 20 comprises a shank 38 extending between its first and second ends 38.1, 38.2, a hexagonal head 40 for screwing in the screw 20, and a breakable junction zone 42 connecting the shank 38 and the head 40. The shank 38 includes a threaded section 44 extending from its first end 38.1, configured to engage with and screw into the threaded section 34.2 of the expanding nut 18. The second end 38.2 of the shank 38 has a frustoconical shape configured to engage with the diameter reduction 28.1 of the tubular body 16.

[0007] The method of assembling such a fastening device includes a step of inserting the device into the through holes 12.1, 14.1 of the first and second parts 12, 14 to be assembled from the bearing surface 12.2 until the frustoconical head 30 of the tubular body 16 is housed in the chamfer 12.3 of the first part 12. The first end 22.1 of the main part 22 is located in projection relative to the bearing surface 14.2 of the second part 14.

[0008] Next, the screw 20 is tightened, the tubular body 16 being prevented from rotating by a tool that cooperates with the detachable part 24 of the tubular body 16. The frustoconical shape of the second end 38.2 of the shank 38 of the screw 20 being abutted against the diameter reduction 28.1 of the tubular body 16, the expanding nut 18 is compressed between its first and second ends 18.1, 18.2, its second end 18.2 being in contact with the first end 22.1 of the main part 22 of the tubular body 16. Tightening the screw then causes the expanding nut 18 to expand, forming a bulb 36. Once this bulb is formed, tightening the screw causes the bulb 36 to be pressed against the bearing surface 14.2 of the second part 14. Consequently, the first and second parts 12 and 14 are compressed between the bulb 36. and the truncated conical head 30 of the tubular body 16.As soon as the desired tightening torque is reached, the joint zone 42 breaks first, and then, under the effect of a complementary movement of the setting tool, the breakable joint zone 26 breaks secondly. The fastening device 10 is then correctly tightened. As illustrated in the figure. figure 3 , the tubular body 16 and the screw 20 are flush with the bearing surface 12.2 of the first part 12.

[0009] This embodiment allows the assembly to be automated with a single tool configured to lock the tubular body 16 in rotation and screw in the screw.

[0010] One solution for dismantling such a fastening device is to destroy the frustoconical shape of the second end 38.2 of the rod 38 using a drill bit. This solution is unsatisfactory because the risk of damaging the bearing surface 12.2 of the first part 12 is significant, given that the tubular body 16 and the screw 20 are flush with said bearing surface 12.2 of the first part 12. Another drawback is that machining the screw 20 generates debris that pollutes the environment if it is not collected. Finally, even if the frustoconical shape of the second end 38.2 of the rod 38 is destroyed, the expanding nut 18 can remain attached to the tubular body 16, since the second end 18.2 of the expanding nut can still be fitted onto the first end 22.1 of the main part 22 of the tubular body 16.

[0011] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0012] To this end, the invention relates to a fastening device for holding together at least two first and second parts, each having a through hole and a bearing surface into which the through hole opens. The fastening device comprises a tubular body, an expanding nut, and a screw. The tubular body is configured to fit into the through holes of the first and second parts and extends between their first and second ends. The first end of the tubular body cooperates with the expanding nut, and the second end of the tubular body has a head configured to bear against the bearing surface of the first part.The expanding nut extends between its first and second ends and has at least one threaded section and an axis of revolution. The expanding nut is configured to expand into a bulb when subjected to a compressive force between its first and second ends. The screw has a shank extending between its first and second ends and has an axis of revolution and an end face at its first end. The shank includes a threaded section that cooperates with the threaded section of the expanding nut, and the second end of the shank has an enlarged shape that bears against the tubular body.

[0013] According to the invention, the screw has at least one shape positioned on the transverse face of the shaft and configured to cooperate with a first tool in order to prevent the screw from rotating about its axis of revolution relative to the first tool. In addition, the expanding nut includes at least one shape configured to cooperate with a second tool in order to prevent the expanding nut from rotating about its axis of revolution relative to the second tool.

[0014] This solution generates no debris during disassembly, reduces the risk of damage to the first and second parts, and allows for the safe separation of the tubular body and the expanding nut. This fastening device enables disassembly of the assembled parts without risk of damage, eliminating the need to re-machine the bores of the assembled parts.

[0015] According to another characteristic, the expanding nut includes a lateral face connecting the first and second ends of the expanding nut and at least one flat positioned on the lateral face.

[0016] According to another characteristic, the lateral face includes several flats regularly distributed around the axis of revolution of the expanding nut.

[0017] According to another feature, each flat is positioned close to the first end of the expanding nut.

[0018] According to another characteristic, the stem includes a recess, coaxial with the axis of revolution of the screw, which opens at the level of the transverse face and has a bottom as well as a lateral face connecting the bottom and the transverse face, the lateral face having at least one flat.

[0019] According to another characteristic, the imprint includes several flats regularly distributed around the axis of revolution of the screw.

[0020] According to another feature, the head is configured to allow it to be immobilized in rotation or driven in rotation with a tool.

[0021] According to another characteristic, the head of the tubular body extends between the first and second transverse faces, the second transverse face being configured to bear against the bearing surface of the first part. In addition, the head comprises a first prismatic section extending from the first transverse face and a second section, extending between the first section and the second transverse face, with a larger cross-section than the first section.

[0022] The invention also relates to an assembly comprising at least first and second parts and at least one fastening device according to one of the preceding characteristics in order to hold the first and second parts assembled.

[0023] The invention also relates to a method for dismantling a fastening device according to one of the preceding characteristics. This dismantling method comprises a step of unscrewing a first element, from among the screw and the expanding nut, relative to a second element different from the first element, from among the screw and the expanding nut, by immobilizing the second element in rotation by means of a first tool and by rotating the first element by means of a second tool.

[0024] According to another feature, the process includes a step of unscrewing the expanding nut from the screw by immobilizing the screw in rotation with the first tool, which cooperates with the imprint of the screw, and by rotating the expanding nut with the second tool which cooperates with the flats of the expanding nut.

[0025] According to another characteristic, prior to the step of unscrewing the expanding nut from the screw or at the beginning of this unscrewing step, the disassembly process includes a step of unlocking the expanding nut from the tubular body by immobilizing the tubular body in rotation by means of a third tool, which cooperates with the head of the tubular body, and by rotating the expanding nut by means of the second tool.

[0026] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which: There figure 1 is a longitudinal section of a fastening device illustrating a prior art embodiment, The figure 2 is a cross-section of an assembly including a fastening device during assembly, illustrating a prior art embodiment, The figure 3 is a cross-section of an assembly including a fastening device at the end of assembly, illustrating a prior art embodiment, The figure 4 is a perspective view from a first angle of a fastening device illustrating one embodiment of the invention, The figure 5 is a perspective view from a second viewing angle of the fastening device visible on the figure 4 , There figure 6is a perspective view of the fastening device visible on the figure 4 in its disassembled state, The figure 7 is a cross-section of an assembly comprising a fastening device illustrating one embodiment of the invention, The figure 8 represents cross-sections illustrating different stages of a dismantling process for the fastening device visible on the figure 4 , There figure 9 is a longitudinal section of a fastening device and dismantling tooling illustrating a step in a dismantling process, and The Figure 10 is a longitudinal section of the fastening device and dismantling tooling visible on the figure 9 illustrating another step in the dismantling process.

[0027] According to an embodiment visible on the figure 7An assembly 46 comprises at least first and second parts 48, 50 and at least one fastening device 52 holding the first and second parts 48, 50 together. The first and second parts 48, 50 each comprise a through hole 48.1, 50.1 and a bearing surface 48.2, 50.2 into which the through hole 48.1, 50.1 opens. The bearing surface 48.2 of the first part 48 may include a chamfer around the through hole 48.1.

[0028] The fastening device 52 comprises a tubular body 54 passing through the first and second parts 48, 50, an expanding nut 56 and a screw 58 which fits into the tubular body and cooperates with the expanding nut 56.

[0029] According to an embodiment visible on the figures 4 to 6, the tubular body 54 comprises a tubular part 60 which extends between first and second ends 60.1, 60.2, a head 62 which extends between first and second transverse faces 62.1, 62.2 (the second end 60.2 of the tubular part 60 being connected to the second transverse face 62.2) as well as a through orifice T60 which opens at the level of the first end 60.1 of the tubular part 60 and the first transverse face 62.1 of the head 62.

[0030] According to one configuration, the tubular part 60 has a cylindrical side face F60 which has a diameter substantially equal to or slightly less than those of the through holes 48.1, 50.1 of the first and second parts 48, 50. The through orifice T60 is smooth.

[0031] The first end 60.1 of the tubular part 60 has a frustoconical shape which flares out towards the second end 60.2.

[0032] The through orifice T60 includes an enlargement, such as a chamfer or a counterbore, at its end opening at the first transverse face 62.1 of the head 62.

[0033] In one embodiment, the head 62 comprises a first section 64.1 with a prismatic, in particular hexagonal, cross-section extending from the first transverse face 62.1, and a second section 64.2 extending between the first section 64.1 and the second transverse face 62.2, with a circular cross-section larger than that of the first section 64.1. This second section 64.2 forms a false washer. This washer allows for a better distribution of forces on the first or second part 48, 50 and improved retention of the fastening device in a setting tool. Of course, the invention is not limited to this (hexagonal) geometry for the head 62. Regardless of the embodiment, the head 62 is configured to allow it to be immobilized against rotation or driven into rotation by a tool.

[0034] In operation, the second transverse face 62.2 of the head 62 is configured to be pressed against the bearing surface 48.2 of the first part 48. The first section 64.1 is used to immobilize the tubular body 54 in rotation with a tool.

[0035] Of course, the invention is not limited to this embodiment for the tubular body 54. The latter could be identical to those of the prior art. Regardless of the embodiment, the tubular body 54 is configured to fit into the through holes 48.1, 50.1 of the first and second parts 48, 50. It comprises a tubular portion 60 extending between the first and second ends 60.1, 60.2 and having an axis of revolution A54, the first end 60.1 cooperating with the expanding nut 56 and having a flared shape towards the second end 60.2, the second end 60.2 having a head 62 configured to bear against the bearing surface 48.2 of the first part 48.

[0036] The expanding nut 56 extends between first and second ends 56.1, 56.2, the second end 56.2 being in contact with the first end 60.1 of the tubular portion 60 of the tubular body 54 in operation. The expanding nut 56 comprises a lateral face 66 and a through hole 68 that connects the first and second ends 56.1, 56.2. The expanding nut 56 is configured to deform and expand so as to form a bulb B56 (visible in the figure7 ) when the expanding nut 56 is subjected to a compressive force between its first and second ends 56.1, 56.2. In operation, the bulb B56 bears against the bearing surface 50.2 of the second part 50.

[0037] Before deformation, the lateral face 66 has a diameter substantially equal to that of the lateral face F60 of the tubular body 54.

[0038] The through hole 68 has a tapped section 68.1 which extends from the first end 56.1 of the expanding nut 56.

[0039] Except for its lateral face 66, the expanding nut 56 may be identical to those of the prior art. Regardless of the embodiment, the expanding nut 56 extends between first and second ends 56.1, 56.2 and includes a through hole 68 that opens at the first and second ends 56.1, 56.2. This through hole 68 has at least one threaded section 68.1 and an axis of revolution A56. The second end 56.2 of the expanding nut 56 cooperates with the first end 60.1 of the tubular portion 60 of the tubular body 54 in operation. The expanding nut 56 is configured to deform and expand to form a bulb B56 when subjected to a compressive force between its first and second ends 56.1, 56.2.

[0040] According to one embodiment of the invention, the expanding nut 56 comprises at least one shape configured to cooperate with a tool in order to prevent the expanding nut 56 from rotating about its axis of revolution A56 relative to the tool. In one embodiment, the lateral face 66 of the expanding nut 56 comprises at least one flat 70. In another configuration, the lateral face 66 comprises several flats 70 regularly distributed around the axis of revolution A56 of the expanding nut 56. By way of example, the lateral face 66 comprises six flats. Of course, the invention is not limited to this geometry for the expanding nut 56. Regardless of the embodiment, the expanding nut 56 is configured to cooperate with a tool in order to prevent it from rotating about its axis of revolution A56 relative to the tool.

[0041] According to an arrangement, each flat 70 is positioned near the first end 56.1 of the expanding nut 56. The flats all have the same length (dimension taken along a direction parallel to the axis of revolution A56 of the expanding nut 56) and are positioned between two transverse planes.

[0042] The screw 58 comprises a shank 72 extending between first and second ends 72.1, 72.2, a hexagonal head 74 for screwing the screw 58, and a breakable junction zone 76 connecting the shank 72 and the head 74. The shank 72 includes a threaded section 78 extending from the first end 72.1, configured to cooperate with and screw into the threaded section 68.1 of the expanding nut 56. The second end 72.2 of the shank 72 includes an enlarged shape 80 configured to bear against the tubular body 54.

[0043] Except for the first end 72.1 of its shank 72, the screw 58 could be identical to prior art screws. Regardless of the embodiment, the shank 72 of the screw 58 extends between the first and second ends 72.1, 72.2 and has an axis of revolution A72 as well as a terminal face F72, at its first end 72.1, substantially perpendicular to the axis of revolution A72. The rod 72 comprises a threaded section 78, which extends from the first end 72.1, configured to cooperate with the tapped section 68.1 of the expanding nut 56 and screw into it, the second end 72.2 of the rod 72 comprising an enlarged form 80 configured to bear against the tubular body 54. According to a particular feature of the invention, the screw 58 has at least one form positioned at the level of the terminal face F72 and configured to cooperate with a tool in order to immobilize the screw 58 in rotation about its axis of revolution A58 relative to the tool.In one embodiment, the rod 72 comprises a recess 82, coaxial with the axis of revolution A58 of the screw 58, which opens at the end face F72 and has a base 82.1 and a lateral face 82.2 connecting the base 82.1 and the end face F72, the lateral face 82.2 having at least one flat. In one arrangement, the recess 82 comprises several flats regularly distributed around the axis of revolution A58 of the screw 58. In one arrangement, the recess 82 comprises six flats and has a hexagonal cross-section. Each flat extends between the end face F72 and the base 82.1. Of course, the invention is not limited to this geometry for the imprint 82. Whatever the embodiment, the screw 58 is configured to cooperate with a tool in order to immobilize it in rotation around its axis of revolution A58 relative to the tool.

[0044] According to a procedure, the fastening device 52 is mounted using substantially the same mounting method as for the prior art fastening devices visible on the figures 1 to 3

[0045] Thus, an assembly method includes a step of inserting the device into the through holes 48.1, 50.1 of the first and second parts 48, 50 to be assembled from the bearing surface 48.2 of the first part 48 until the head 62 of the tubular body 54 is in contact with the bearing surface 48.2 of the first part 48. The first end 60.1 of the tubular body 54 is located in projection relative to the bearing surface 50.2 of the second part 50.

[0046] Next, the screw 58 is screwed in with a first tool, the tubular body 54 being immobilized in rotation by means of a second tool which cooperates with the head 62 of the tubular body 54. The second section 64.2 of the head 62, which forms a false washer, limits the risks of damage to the first part 48 with the second tool.

[0047] When the screw 58 is tightened, the expanding nut 56 is compressed between its first and second ends 56.1, 56.2, its second end 56.2 being in contact with the first end 60.1 of the tubular part 60 of the tubular body 54. This tightening causes the expanding nut 56 to expand, forming a bulb B56. Once this bulb is formed, tightening the screw causes the bulb B56 to be pressed against the bearing surface 50.2 of the second part 50. Consequently, the first and second parts 48 and 50 are compressed between the bulb B56 of the expanding nut 56 and the head 62 of the tubular body 54. As soon as the desired tightening torque is reached, the breakable joint zone 76 of the screw 58 breaks. The fastening device 52 is then correctly tightened.

[0048] A method for dismantling the fastening device 52 is described with regard to the figures 8 to 10This disassembly procedure includes a step of unscrewing a first component, either screw 58 or expanding nut 56, relative to a second component, different from the first, also either screw 58 or expanding nut 56. This is achieved by immobilizing the second component against rotation with a first tool and rotating the first component with a second tool. According to one procedure, the tubular body 54 can be immobilized prior to the unscrewing step to loosen the expanding nut 56.

[0049] According to a preferred embodiment visible on the figures 8 to 10The disassembly process includes a step of unscrewing the expanding nut 56 relative to the screw 58 by immobilizing the screw 58 in rotation by means of the first tool 84, which cooperates with the recess 82 of the screw 58, and by rotating the expanding nut 56 by means of the second tool 86 which cooperates with the flats 70 of the lateral face 66 of the expanding nut 56. By way of example, the first tool 84 is a hex key and the second tool 86 is a socket key.

[0050] According to one embodiment, prior to or at the beginning of the unscrewing step of the expanding nut 56 relative to the screw 58, the disassembly process includes a step of unlocking the expanding nut 56 relative to the tubular body 54 by immobilizing the tubular body 54 against rotation using a third tool 88, which cooperates with the first section 64.1 of the head 62 of the tubular body 54, and by rotating the expanding nut 56 using a second tool 86. For example, the third tool 88 is a socket wrench. This unlocking step becomes necessary if the recess 82 of the screw 58 is insufficient to unlock the expanding nut 56 at the beginning of the unscrewing step due to the significant pressure exerted by the expanding nut 56 on the tubular body 54.

[0051] As illustrated on the figure 9Initially, the third tool 88 is fitted onto the head 62 of the tubular body 54. Subsequently, the first tool 84 is inserted into the recess 82 of the screw 58, as illustrated in the figure 9 and parts (A) and (B) of the figure 8 and the second tool 86 is fitted onto the expanding nut 56 by making it cooperate with the flats 70, as illustrated in parts (C) and (D) of the figure 8 The third tool 88 immobilizes the tubular body 54 in rotation, and the second tool 86 is then set in rotation, as illustrated in the figure 9 Then, the expanding nut 56 is unscrewed with the second tool 86 while holding the screw 58 in place and preventing it from rotating using the first tool 84, as illustrated in part (D) of the figure 8 and the Figure 10 .

[0052] At the end of the unscrewing step, the expanding nut 56 is separated from the screw 58. From then on, the tubular body 54 and the screw 58 can be removed from the through holes 48.1, 50.1 of the first and second parts 48, 50.

[0053] This operating method does not generate any debris and allows the tubular body 54 and the expanding nut 54 to be safely separated.

[0054] According to an embodiment visible on the Figures 9 and 10 , the same tooling 90 supports the first and second tools 84, 86, the tooling 90 comprising a support 92, a fixed link 94 connecting the support 92 and the first tool 84 and a pivoting link 96 which connects the support 92 and the second tool 86.

Claims

1. Fastening device for keeping at least first and second parts (48, 50) assembled, each of which has a through-hole (48.1, 50.1) and a bearing surface (48.2, 50.2) into which the through-hole (48.1, 50.1) opens, said fastening device comprising a tubular body (54), an expansion nut (56) and a screw (58); the tubular body (54) being designed to be seated in the through-holes (48.1, 50.1) of the first and second parts (48, 50) and extending between first and second ends (60.1, 60.2), the first end (60.1) of the tubular body (54) cooperating with the expansion nut (56), the second end (60.2) of the tubular body (54) having a head (62) designed to bear against the bearing surface (48.2) of the first part (48); the expansion nut (56) extending between first and second ends (56.1, 56.2), having at least one threaded section (68.1) and an axis of revolution (A56), the expansion nut (56) being designed to expand to form a bulb (B56) when subjected to a compressive force between the first and second ends (56.1, 56.2) thereof; the screw (58) having a shank (72) that extends between first and second ends (72.1, 72.2) and has an axis of revolution (A72) and an end face (F72) at the first end (72.1) thereof, the shank (72) comprising a threaded section (78) which cooperates with the threaded section (68.1) of the expansion nut (56), the second end (72.2) of the shank (72) having an enlarged shape (80) bearing against the tubular body (54); wherein the screw (58) has at least one shape, on the transverse face (F72) of the shank (72), designed to cooperate with a first tool (84) to prevent the screw (58) from rotating about the axis of revolution (A72) thereof with respect to the first tool (84), and wherein the expansion nut (56) has at least one shape designed to cooperate with a second tool (86) to prevent the expansion nut (56) from rotating about the axis of revolution (A56) thereof with respect to the second tool (86).

2. Fastening device as claimed in the preceding claim, wherein the expansion nut (56) comprises a lateral face (66) connecting the first and second ends (56.1, 56.2) of the expansion nut (56), as well as at least one flat (70) positioned on the lateral face (66).

3. Fastening device as claimed in the preceding claim, wherein the lateral face (66) comprises several flats (70) regularly distributed about the axis of revolution (A56) of the expansion nut (56).

4. Fastening device as claimed in one of claims 2 and 3, wherein each flat (70) is positioned close to the first end (56.1) of the expansion nut (56).

5. Fastening device as claimed in one of the preceding claims, wherein the shank (72) comprises a recess (82), coaxial with the axis of revolution (A58) of the screw (58), which opens into the transverse face (F72) and has a bottom (82.1) and a lateral face (82.2) connecting the bottom (82.1) and the transverse face (F72), the lateral face (82.2) having at least one flat.

6. Fastening device as claimed in the preceding claim, wherein the recess (82) comprises several flats regularly distributed about the axis of revolution (A58) of the screw (58).

7. Fastening device as claimed in one of the preceding claims, wherein the head (62) is designed to allow it to be prevented from rotating or to be driven in rotation using a tool.

8. Fastening device as claimed in the preceding claim, wherein the head (62) of the tubular body (54) extends between first and second transverse faces (62.1, 62.2), the second transverse face (62.2) being designed to bear against the bearing surface (48.2) of the first part (48), and wherein the head (62) comprises a first section (64.1) of prismatic cross-section which extends from the first transverse face (62.1) and a second section (64.2) which extends between the first section (64.1) and the second transverse face (62.2), which is larger in cross-section than the first section (64.1).

9. Assembly comprising at least first and second parts (48, 50) and at least one fastening device as claimed in one of the preceding claims for keeping the first and second parts (48, 50) assembled.

10. Method for removing a fastening device as claimed in one of claims 1 to 8, wherein the removal method comprises a step of unscrewing a first element, which is either the screw (58) or the expansion nut (56), with respect to a second element, which is different from the first element and is either the screw (58) or the expansion nut (56), by preventing the second element from rotating using a first tool (84) and pivoting the first element using a second tool (86).

11. Removal method as claimed in the preceding claim, wherein the method comprises a step of unscrewing the expansion nut (56) with respect to the screw (58) by preventing the screw (58) from rotating using the first tool (84), which cooperates with the recess (82) in the screw (58), and pivoting the expansion nut (56) using the second tool (86), which cooperates with the flats (70) of the expansion nut (56).

12. Removal method as claimed in the preceding claim, wherein, before the step of unscrewing the expansion nut (56) with respect to the screw (58) or at the beginning of this unscrewing step, the removal method comprises a step of unlocking the expansion nut (56) with respect to the tubular body (54) by preventing the tubular body (54) from rotating using a third tool (88), which cooperates with the head (62) of the tubular body (54), and pivoting the expansion nut (56) using the second tool (86).