Temporary fastener for structures

The present invention concerns a fastener (110) for the temporary assembly of at least two previously drilled structures (112) comprising:      The connecting element is traversed by a lateral opening (70) axially extended between two closed ends (72, 74); and the fastener also comprises a transverse stop (28) secured to the spacer, the said stop being capable of sliding between the axial ends of the said lateral opening.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/EP2019/059895, filed Apr. 17, 2019, which claims priority from FR 1853326 filed Apr. 17, 2018, the entire contents of which are incorporated herein by reference.

The present invention concerns a temporary fastener for the temporary assembly of at least two previously drilled structures of the type comprising: a hollow body, extending along a main axis, a first end of said body having a bearing surface substantially perpendicular to the main axis; a plurality of elastic clips movable relative to the body and extending substantially parallel to the main axis, a first end of each elastic clip comprising a hooking spur, the said hooking spurs forming a projection relative to the bearing surface of the body; a spacer extending along the main axis, a first end of the spacer forming a projection relative to the bearing surface, the plurality of elastic clips positioned around the said first end, a second end of the spacer being positioned within the body; a connecting member movable relative to the body and extending along the main axis within said body, a first end of said connecting element secured to a second end of each elastic clip; and—an actuating element connected to a second end of the connecting element by a thread/tapping type mechanism.

The invention relates particularly to temporary fasteners of the insertable clamp type.

In the aeronautical industry, before performing the final assembly of two structural elements, it is common practice to carry out a temporary assembly of the elements using temporary fasteners inserted into the through-holes. Temporary fasteners of this type are described in document EP0336808.

In similar devices, it is common practice to connect the hollow body and the elastic clips by means of an assembly part that passes between said clips. Since the function of such an assembly part is to prevent the rotation of the clips in relation to the body, its thickness increases the space between the clips, and thus limits the thickness of the clips.

Document EP0336808 refers to a temporary fastener comprising two elastic clips. It is beneficial, however, to increase the number of elastic clips so as to enlarge the gripping surface area of the structures to be assembled.

The purpose of this invention is to provide a connecting mechanism between the hollow body and the elastic clips, preserving the maximum thickness of said clips so that more than two clips can be provided for.

To this end, the object of the invention is to provide a fastener of the aforementioned type, in which the connecting element is crossed by a lateral opening substantially positioned in a transverse direction, perpendicular to the main axis, the lateral opening extending axially between the first and second closed ends; the fastener also comprises a stop extending in a transverse direction and secured to the spacer, the said stop being positioned in the lateral opening of the connecting element, allowing it to slide between the first and second axial ends of said lateral opening.

Following other advantageous aspects of the invention, the fastener comprises one or more of the following features, taken individually or according to all technically possible combinations:the fastener also comprises a compression spring positioned within the body around the connecting element, the spring being capable of compressing along the main axis, an end of said spring being capable of entering into contact with the stop on either side of the connecting element;the second end of the connecting element comprises a thread and the actuating element comprises a tapping co-operating with said thread;the second end of the spacer is crossed by a through-hole positioned in a transverse direction, and the stop is a pin assembled to said through-hole;the plurality of elastic clips includes at least three elastic clips and preferably at least four elastic clips;the stop is secured in place along the main axis relative to the body;the fastener also comprises a sleeve positioned within the body around the connecting element, the sleeve being secured relative to the body, a first end of said sleeve consisting of two notches extending axially and positioned opposite each other in relation to the main axis, the stop crosses the said notches and is able to slide into the notches along the main axis;the compression spring is positioned around the sleeve;a first end of the actuating element is positioned within the body and a second end of the actuating element forms a projection relative to a second end of said body;the second end of the actuating element comprises a coupling element for coupling with a rotary installation tool; andthe second end of the actuating element also has a collar forming an outer radial projection.

The invention also relates to an installation nose for the assembly of a fastener with at least two previously drilled structures, the said fastener being as previously described and comprising the collar, said installation nose comprising: a device to prevent rotation of the body; a rotary installation tool incorporating a means of coupling with the coupling element of the second end of the actuating element to drive the actuating member into rotation; and an elastic interlocking device on the collar to axially maintain the fastener assembled to the installation nose.

The invention further relates to an assembly comprising: structures to be assembled, including a first and a second opposite face, and a bore opening on to each of said first and second faces; and a fastener as described above, the plurality of elastic clips being positioned in the bore, the bearing face of the body and the hooking spurs coming into contact with the first and second faces respectively, the spring exerting a tension tending to move the bearing surface and the hooking spurs closer together along the main axis.

DETAILED DESCRIPTION

FIGS.1-3and5-7respectively show a fastener10according to a first embodiment of the invention and a fastener110according to a second embodiment of the invention.FIG.9shows an assembly200comprising fastener10ofFIGS.1-3and an installation nose202for the installation of said fastener10.

In the following description, fasteners10and110will be described simultaneously, the elements similar to both fasteners being identified by the same reference numbers.

Fastener10,110is suitable for temporary assembly on at least two structures12,112, shown inFIGS.3and7, to form an assembly13,113. For the purpose of simplification, structures12,112are represented in a single piece, defining two opposite faces14,16. A bore18crosses structures12,112from the first face14to the second face16.

As it will be specified later, structures12inFIG.3form a Pminthickness corresponding to the minimum thickness of the structures that can be assembled by the fastener10. In contrast, structures112inFIG.7form a Pmaxthickness corresponding to the maximum thickness of the structures that can be assembled by the fastener110. The thickness corresponds to the distance between the first face14and the second face16.

The fastener10,110extends along a main axis20and consists of: a body22,122; elastic clips24; a spacer26; a pin28; a connecting element30,130; an actuating element32,132; and a spring34,134. The fastener110according to the second embodiment of the invention also comprises a sleeve136.

FIG.4shows the elastic clips24, the spacer26, the pin28and the connecting element30of fastener10.FIG.8shows, in an exploded perspective view, the elastic clips24, the spacer26, the pin28and the connecting element130as well as the sleeve136of the fastener110.

As will be detailed later, the second embodiment inFIGS.5to8is specially designed with compact bulk along the main axis20.

Body22,122is hollow, with an inner cavity38,138of a substantially cylindrical shape. A first axial end of body22,122, known as the front end, includes a bearing surface40substantially perpendicular to the main axis20. The said bearing surface40is able to come into contact with the first face14of structures12,112. The bearing surface40comprises a first central opening42communicating with the inner cavity38,138.

A second axial end of body22,122, referred to as the rear end, comprises a second central opening44communicating with the inner cavity38,138. The second central opening44preferably has a larger diameter than the first central opening42.

The first42and second44central openings open onto walls43,45, known respectively as the front wall and the rear wall, of the inner cavity38,138. Each of the front43and rear45walls is substantially perpendicular to the main20axis.

In the second embodiment inFIGS.5to8, the body122consists of an inner crown146forming an axial projection relative to the front wall43. A rear surface147of said inner crown, facing towards the rear end of body122, is capable of forming an axial stop as described below.

The body22,122also comprises two lateral openings48, of substantially circular shape. The lateral openings48communicate with the inner cavity38,138and are located opposite each other relative to the main axis20. The said lateral openings48form a transverse axis50perpendicular to the main axis20. Following the description, an orthonormal basis (X, Y, Z), the longitudinal X and transversal Y directions representing the respective directions of the main axis20and the transverse axis50are considered.

Close to the front wall43, the inner cavity38,138comprises rotation preventing elements, such as flats51,151parallel to the main axis20and positioned around said axis. In the second embodiment inFIGS.5to8, flats151are positioned on the inner crown146.

In the second embodiment inFIGS.5to8, the body122of the fastener110is formed from one part. In the first embodiment inFIGS.1to4, the body22of fastener10comprises a main part, including the rear end, and a cap52including the front end and the bearing surface40. The main part and the cap52are secured to each other.

In the second embodiment inFIGS.5to8, an external surface of the body122consists of rotation preventing elements, such as flats154parallel to the main axis20and positioned around said axis. The flats154are capable of preventing rotation of the body122in an installation nose (not shown) similar to the installation nose202inFIG.9.

The elastic clips24are designed to cross the bore18of the structures12,112. The elastic clips24are substantially identical, with at least two of them, and ideally at least three or four of them included. In the first and second embodiments shown, there are four elastic clips24.

The elastic clips24extend substantially parallel to the main axis20and are positioned substantially regularly around said axis.

A first end of each elastic clip24includes a hooking spur56, which is able to come into contact with the second face16of structures12,112.

The elastic clips24pass through the first central opening42of the body22,122, with the hooking spurs56forming a projection relative to the bearing surface40. As described hereafter, the elastic clips24are movable in axial translation relative to the body22,122and are rotationally fixed relative to said body.

The spacer26extends along the main axis20and passes through the first central opening42of body22,122. As described hereafter, in the first embodiment inFIGS.1to4, the spacer26is secured relative to body22. On the other hand, in the second embodiment inFIGS.5to8, the spacer26is movable in axial translation relative to body122.

A first end58of the spacer26, known as the front end, forms an axial projection relative to the bearing surface40of the body22,122, the elastic clips24being positioned around the said forward end58. A second end60of the spacer26is positioned in the inner cavity38,138of the body22,122. The said second end60of the spacer26is crossed by a transverse hole62positioned along the Y transversal direction.

The pin28extends along the transverse Y direction through the through-hole62of the spacer26. In the first embodiment inFIGS.1to4, the ends64of the pin28are inserted into the lateral openings48of the body22, securing said pin28and the spacer26to the body22of the fastener10. The pin28thus extends along the transverse axis50.

In the second embodiment inFIGS.5to8, however, the ends64of the pin28are positioned within the inner cavity138of the body122of fastener110, set back from the lateral openings48of said body122. As described hereafter, the spacer26and the pin28are movable in translation along X relative to the body122, of the fastener110and rotationally fixed relative to said body.

The connecting element30,130extends along the main axis20and is at least partially positioned within the inner cavity38,138of the body22,122. A first end of the said connecting element30,130is secured to a second end, opposite to the hooking spur56, of each elastic clip24.

The connecting element30,130, hereinafter referred to as the hollow rod, is of tubular shape. The first end of said hollow rod30,130has an axial hole65around which the elastic clips24are positioned. The said first end of the hollow rod30,130also comprises a shoulder66forming an axial stop with the front wall43of the inner cavity38,138, so as to maintain said shoulder66on the inside of the inner cavity.

A second end of said hollow rod30,130, facing towards the rear end of the body22,122, has a substantially rotationally cylindrical external surface and comprises a thread67. In the first and second embodiments represented, the second end of said hollow rod30,130is closed by a plug68.

The hollow rod30,130comprises two lateral slots70,170, positioned opposite each other relative to the main axis20and extending along X between a first72and a second74closed ends. The first72and second74ends of the lateral slots70,170are facing respectively towards the thread67and towards the elastic clips24.

The spacer26passes through the axial opening65of the hollow rod30,130, the second end60of the spacer being positioned inside said hollow rod. The pin28extends transversely through the lateral slots70,170, enabling them to slide along X between the first72and second74ends of said lateral slots.

In the first embodiment inFIGS.1to4, the pin28being fastened relative to the body22, the plurality of elastic clips24/the hollow rod30of fastener10is thus rotationally fixed around the main axis20relative to said body22.

In the first embodiment inFIGS.1to4, near the first end of the hollow rod30of the fastener10, an external surface of said hollow rod also comprises flats76co-operating with the flats51of the inner cavity38. Flats51and76form an additional means of rotationally preventing the hollow rod30in the body22, avoiding any torque being exerted on the rod during use of the fastener10.

In the second embodiment inFIGS.5to8, the sleeve136of the fastener110extends along the main axis20, between the first and second open ends. The sleeve136is fully contained in the inside of the inner cavity138of the body122and is locked in axial translation on the inside of said inner cavity. The first and second ends of the sleeve are facing towards the front and rear ends of the body122respectively.

Near to the first end of the sleeve136, an external surface of said sleeve comprises flats178co-operating with the flats151of the inner cavity138, so as to prevent rotation of the sleeve136in the body122.

The hollow rod130is positioned on the inside of the sleeve136, forming a projection relative to the first end of said sleeve.

The sleeve136comprises two lateral notches180, positioned opposite each other relative to the main axis20and extending along X. A first end of said notches180is open onto the first end of the sleeve136. A second end182of said notches180is closed.

The pin28extends transversely through the lateral notches180, so as to ensure sliding along X between the first and second182ends of said lateral notches180. Via the intermediary of the sleeve136, the pin28, the spacer26and the set of elastic clips24/the hollow rod130are thus rotationally fixed around the main axis20relative to the body122of the fastener110.

The actuating element32,132, hereinafter referred to as the drive nut, is of tubular shape extending along the main axis20. The drive nut32,132passes through the second central opening44of the body22,122. A first end of said drive nut32,132, positioned in the inner cavity38,138of the body22,122, comprises a tapping84capable of cooperating with the thread67of the hollow rod30,130. The said first end of the said drive nut32,132also comprises a shoulder85forming an axial stop with the rear wall45of the inner cavity38,138, so as to maintain said shoulder85on the inside of the inner cavity.

In the first embodiment inFIGS.1to4, the first end of the drive nut32ends on a surface86which is substantially flat and perpendicular to the main axis20, known as the front face of the drive nut32.

A second end of the drive nut32,132, said rear end, forms a projection on the exterior of the body22,122. The said rear end comprises a lateral assembly surface88with an installation tool such as the nose installation piece202inFIG.9, which will be described later. The lateral assembly surface88is capable of preventing rotation of the drive nut32,132relative to the said installation tool. In the example shown, the lateral assembly surface88forms a hexagonal shape.

In the first embodiment inFIGS.1to4, the second end of the drive nut32also includes a collar89, or shoulder, adjacent to the lateral assembly surface88and forming a radial projection relative to the said lateral assembly surface. In the example shown, the collar89is part of the drive nut32. As a variation, not shown, the collar may be used as an insert piece.

The spring34,134extends along the main axis20, between a first90and second92ends. The said spring34,134is entirely contained within the inner cavity38,138of the body22,122. The spring34,134is capable of being compressed along the main axis20.

In the first embodiment inFIGS.1to4, the spring34of the fastener10is formed from a stack of elastic washers positioned around the hollow rod30. The spring34is axially contained between the pin28, secured to the body22, and the front face86of the drive nut32.

In the second embodiment inFIGS.5to8, the spring134of the fastener110is a helical spring, positioned around the sleeve136. A first end90of the spring134is in contact with the ends64of the pin28. The second end92of said spring134acts as an axial stop against the rear wall45of the inner cavity38,138, around the second central opening44. The spring134thus exerts a force on the pin28along the X direction, facing towards the front end of the body122.

The assembly200inFIG.9represents the fastener10of the first embodiment, assembled to an installation nose202as part of a method for installing said fastener. This method will be described later.

The installation nose202extends along an installation axis203, as shown inFIG.9, with the main axis20of the fastener10. The installation nose202includes a tubular support204. Inside the said tubular support, the said installation nose also comprises: a roller cage206, a crown208, a rotating wrench210, a set of holding claws212and an ejector rod214.

A first axial end of the tubular support204, known as the front end, comprises a front opening216. A second axial end (not shown) of the tubular support204is able to connect to an installation machine (not shown). The roller cage206is axially adjacent to the front opening216and comprises in particular a set of rollers217, extending along the installation axis203and positioned around the said axis. The said roller cage206, for example similar to the device described in document EP2999571, is designed to prevent rotation of the body22of the fastener10, which has a rotationally cylindrical outer surface.

The crown208is axially adjacent to the roller cage206, opposite the front opening216. The crown208forms an inner radial projection in the tubular support204.

The rotating wrench210is positioned inside the tubular support, opposite the front opening216relative to the crown208. The rotating wrench210also has a tubular shape, positioned according to the installation axis203.

A first axial end of the said wrench, known as the front end, comprises an assembly head218. The said assembly head comprises an indentation of220, which can be assembled with the lateral assembly surface88of the drive nut32of the fastener10. A second axial end (not shown) of the said wrench is able to connect to a rotational driving device of the installation machine (not shown).

The rotating wrench210is axially movable relative to the tubular support204. More precisely, the said wrench comprises a compression spring222, which exerts an axial force on the assembly head218, facing towards the front opening216.

The holding claws212extend substantially along the installation axis203and are positioned around the rotating wrench210. Preferably, there should be three or four holding claws212.

A first axial end of each holding claw212forms a hook224in a radial projection towards the interior. The hooks224are positioned axially between the crown208and the assembly head218of the rotating wrench210.

A second axial end (not shown) of each holding claw212is secured to the tubular support204. The holding claws are flexible, the hooks224are able to radially move apart and move closer to each other.

The ejector rod214is positioned along the installation axis203within the rotating wrench210. The ejector rod214comprises a front bearing surface226, facing the front opening216of the tubular support204. The ejector rod214is movable in axial translation relative to said tubular support.

A method for installing the fastener10,110in the structures12,112to form an assembly13,113, will now be described.

At the beginning of the installation method, the fastener10,110is in a first configuration, known as a free configuration, as shown respectively inFIGS.1-2for fastener10and5-6for fastener110. In the free configuration, the washers forming the spring34of fastener10are not compressed. In the second embodiment inFIGS.5to8, the spring134of the free-configuration fastener110is in a state of partial compression; said spring holds the pin28as a stop against the rear surface147of the inner crown146of the body122.

Additionally, in the free configuration, the drive nut32,132forms an axial projection of maximum length along the main axis20, relative to the rear end of the body22,122. The shoulder85of the said drive nut forms a stop against the rear wall45of the inner cavity38,138.

In addition, in the free configuration, the shoulder66of the hollow rod30,130forms a stop against the front wall43of the inner cavity38,138. The pin28is close to the second end74of the lateral slots70,170of said hollow rod30,130. The elastic clips24form an axial projection of maximum length on the main axis20, relative to the bearing surface40of body22,122. The forward end58of the spacer26is set back from the hooking spurs56of said clips. The said spurs56are thus in contact with each other, forming a minimum diameter perpendicular to the main axis20.

During the first stage of the installation method, the fastener10,110in free configuration is assembled to a machine (not shown) equipped with an installation tool such as the nose installation piece202inFIG.9. The first phase will be described hereafter for the fastener10of the first embodiment:

At the beginning of the first phase of the method for installing, the ejector rod214of the nose installation piece202is in a retracted configuration, the front bearing surface226being rearward relative to the hooks224of the claws212. The fastener10is inserted into the front opening216of the tubular support204of the nose installation piece, by the rear end of the drive nut32. The axial displacement of the said drive nut32drives the holding claws212to radially separate around the lateral assembly surface88. The said lateral assembly surface is assembled with the indentation220of the rotary wrench210, until the body22forms an axial stop against the crown208. The collar89also forms an axial stop against the assembly head218. In addition, the hooks224, having passed said collar89, move closer to each other, the claws212elastically interlocking on the collar. The drive nut32is thus axially maintained between the assembly head218and the hooks224. The fastener10can then be moved by the installation machine without falling.

During the second phase of the installation method, the fastener10,110is assembled to the structures12,112. The second phase is described below for both installation methods:

In the first stage of the installation method, the elastic clips24are introduced into the bore18of the structures12,112, from the first face14. Then, the bearing surface40of the body22,122comes into contact with said first face14. The hooking spurs56therefore form an axial projection relative to the bore18and the second face16of the structures12,112.

In the second stage, the body22,122is rotationally fixed relative to the structures12,112. In the case of fastener10, this rotational prevention is performed by the roller cage206of the installation nose202.

In addition, the installation tool, coupled to the assembly surface88of the drive nut32,132, imposes on said drive nut a rotational motion around the main axis20. In the case of the fastener10, the rotation is imposed by the rotary wrench210.

Under the action of said rotation motion, the cooperation of the tapping84of the drive nut32,132with the thread67of the hollow rod30,130drives said hollow rod and the elastic clips24in axial displacement towards the rear end of the body22,122. The pin28being held in a fixed position relative to the body22,122, said pin slides in the lateral slots70,170of the hollow rod30,130, in the direction of the first end72.

Similarly, the spacer26being held in a fixed position relative to the body22,122by the pin28, the rotation motion of the drive nut32,132drives the hooking spurs56to move closer to the front end58of said spacer. When the said spurs56axially arrive at the level of said front end58, the elastic clips24deform and the hooking spurs56move apart from each other.

The hooking spurs56thus offer a grip with the second surface16of the structures12,112, at the edge of the bore18. This configuration of the fastener10,110, known as the intermediate configuration, corresponds to an assembly of structures with a Pmaxthickness, as shown inFIGS.7and8for the fastener110.FIG.4also shows the elastic clips24, the spacer26, the pin28and the connecting element30of the fastener10in the intermediate configuration corresponding to a Pmaxthickness.

The following description relates specifically to the fastener10of the first embodiment inFIGS.1to4. As shown inFIG.4, in the intermediate configuration, the pin28of the fastener10is substantially the same distance from the first72and second74ends of the lateral slots70of the hollow rod30.

If the structures12to be assembled are of a lesser thickness than the Pmax, the rotation motion of the drive nut32is continued from the intermediate configuration. The hollow rod30continues to move towards the rear of the body22until the hooking spurs56come into contact with the second face16of the structures12.

The configuration inFIG.3, known as the minimum configuration, corresponds to an assembly of fastener10to the structures12of the Pminthickness. This minimum configuration corresponds to a minimum clearance between the pin28and the first end72of the lateral slots70of the hollow rod30.

Regardless of the thickness of the structures12, after hooking the spurs56against the second face16, the continuation of the rotation motion of the drive nut32compresses the washers34between the pin28and said drive nut32. This compression makes it possible to apply a tension in the fastener10, such a tension being, for example, parameterized at the installation nose202. It is therefore necessary to maintain a clearance, even if a weak one, between the pin28and the first end72of the lateral slots70.

The following description relates specifically to the fastener110of the second embodiment inFIGS.5to8. As mentioned above, the fastener110has a short length along the main axis20. In particular, the length of the lateral slots170is less than the travel of the hollow rod130in the body122between the free configuration inFIGS.5and6and the intermediate configuration inFIGS.7and8. This short length of the lateral slots170makes it possible to use a particularly short hollow rod130.

As a result, during the rotation of the drive nut132from the free configuration inFIGS.5and6, the contact of the pin28with the first end72of the lateral slots170is substantially simultaneous to the alignment of the hooking spurs56with the first end58of the spacer26. The spacer assembly26/pin28and the set of elastic clips24/hollow rod130are thus in the configuration as shown inFIG.8.

The rotational continuation of the rod132jointly drives the hollow rod130, the elastic clips24, the pin28and the spacer26towards the rear of the body122. The pin28slides in the lateral notches180of the sleeve136, compressing the helical spring134.

As shown inFIG.7, in the intermediate configuration corresponding to the structures112with a Pmaxthickness, the pin28is slightly moved away from the axial stop147, which allows the spring134to apply tension in the fastener110.

Depending on the thickness of the structures112to be assembled, the rotation of the drive nut132can be continued up to a maximum compression of the spring134. The fastener110is then in the minimum configuration, corresponding to the structures of Pminthickness. In the minimum configuration, the pin28is close to the second end182of the lateral notches180of the sleeve136.

In accordance with embodiments, not shown, of the fastener, the pin28inserted in the transverse hole62of the spacer26is replaced by a stop secured to the spacer, said stop being capable of sliding in the lateral slots of the connecting element.

During the third phase of the installation method, the fastener10,110assembled to the structures12,112is separated from the installation tool. The third phase will be described hereafter for the fastener10of the first embodiment:

As shown inFIG.9, the ejector rod214is axially thrust forward, with the front bearing surface226forming an axial stop against the drive nut32. The fastener10is thus pushed to the exterior of the tubular support204. Under the action of said axial thrust, the holding claws212move apart from each other, releasing the collar89.

After the installation as described above of the fastener10,110in the structures12,112, a method of disassembly of the assembly13,113thus formed is performed by turning the drive nut32,132in the opposite direction, so as to return the fastener10,110to a free configuration. The said fastener10,110can therefore be separated from the structures12,112and reused.

The presence of the sleeve136in the fastener110of the second embodiment limits the total length of said fastener according to the main axis20, without reducing the Pmin-Pmaxrange of thicknesses for structures112to be assembled by the fastener110.

In addition, in the minimum configuration of the fastener10of the first embodiment, the first end58of the spacer26forms a projection relative to the hooking spurs56, as shown inFIG.3. In the minimum configuration of the fastener110of the second embodiment, however, the first end58of the spacer26is aligned with the said hooking spurs56, as in the intermediate configuration inFIGS.7and8. The second installation method inFIGS.5to8thus allows an assembly113with a small dimension on the side of the second face16of the structures112.

In the installation methods inFIGS.1-4and5-8, the fastener10,110can be disassembled so that any of the elements can be changed, if found to be deteriorated by previous uses. In particular, the set of elastic clips24/hollow rod, the spacer26, the pin28and possibly the cap68are susceptible to require changing.

A method for disassembling the fastener10inFIGS.1to4, for example, is described below: the fastener10being in the free configuration ofFIGS.1and2, the pin28is removed from the rest of the fastener by pressing a sharp tool into the lateral openings48of the body22. The cap52is then disassembled and the clips24and the spacer26are removed from the front end of the body22.

A method for disassembling the fastener110inFIGS.5-8, for example, is described below: the fastener10being in the free configuration ofFIGS.5and6, the pin28is removed from the body122as previously described. Then the drive nut132is rotated so as to screw the hollow rod130until it emerges from the second end of said drive nut. The set of elastic clips24/hollow rod130is then separated from said drive nut, then the plug68and the spacer26are extracted from it by means of a tool.