Connection system

Abstract

The invention relates to a connection system for connecting a front element (1) and a rear element (2), comprising: a threaded bolt (4) having a rear portion (4.1) and a front portion (4.2); a sleeve (5) concentrically surrounding the threaded bolt (4), tapering towards a rear portion (4.1) of the threaded bolt; a housing (7) for the sleeve (5); and a fastening element (6) configured to be in threaded connection with the threaded bolt (4), the sleeve (5) having a substantially elliptical rear section (5.3).

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of systems for the connection between structural elements. More particularly, the present invention relates to the connection between panels in the aeronautical industry. BACKGROUND

[0002] Many systems are known for the connection between two structures, which have holes for the insertion of the elements of the connection system.

[0003] For example, screwing structural connections are known. The drawback of these connections is that they require the elements to be connected to be positioned in a position of precise alignment, since this type of connection is not able to absorb misalignments. Furthermore, these connections are not able to control the loads transmitted during the assembly and disassembly of the connection system. Furthermore, it is sometimes difficult to disassemble the system, since it is necessary to access both sides of the connection system, which is not always possible or easy.

[0004] Gap-fit type connections are also known. The drawback of said connections is that they have no ability to absorb misalignments between the elements to be connected, and are not able to control the loads transmitted by the connection system when assembling and disassembling the connection system. Furthermore, with this type of connection system, the bolts can have a loose fit and have a poor load transmission due to the gap fit.

[0005] Quick couplings are also known. This type of connection can indeed absorb misalignments between the elements to be connected to a lesser extent. However, this type of connection also has the drawback of a loose fit of the bolts and poor load transmission. Another drawback of them is the need for vertical installation, since they are installed in the direction of the threaded portion, which is perpendicular to the connection and cannot be inclined.

[0006] Fixing with a conical sleeve is also known. This type of fixing can absorb slight misalignments, but it requires the holes in the elements to be connected to be conical.

[0007] Connection systems for use in doors in the aeronautical industry are also known, such as door locks. The drawback of these systems is that they are not able to absorb structural loads and tend to be complex. Also known are door latches, which have the drawback of being substantially heavy due to their complexity. Furthermore, this type of connection can only absorb axial loads.

[0008] Furthermore, when the hole in the first element and the hole in the second element to be assembled together are not perfectly aligned before their assembly, it can be difficult to introduce the elements of the connection system. SUMMARY

[0009] The present invention aims to solve these technical problems by providing a connection system which allows a simple and effective mechanical connection even when faced with adverse conditions such as those described previously.

[0010] The present invention proposes a connection system according to the main technical solution of the invention. The present invention also proposes a connection system according to the dependent technical solutions of the invention.

[0011] The present invention provides a connection between elements, more particularly for connecting structural elements, such as large panels, together, or connecting a panel to a structure. The aim of the present invention is to make the connection system easy to assemble and disassemble and to absorb misalignments between the elements to be connected.

[0012] More particularly, the system according to the invention allows a connection between at least a first element of the front and a second element of the rear, each of the elements comprising a through hole for its assembly. More particularly, the invention applies to elements having a circular cross-section assembly hole.

[0013] The threaded bolt has an elongated shape, substantially cylindrical along a longitudinal direction.

[0014] With reference to the direction of insertion of the connection system through the holes in the first and second elements, the front is defined as in front and the rear is defined as in back.

[0015] The transverse cross-section is defined as the cross-section perpendicular to the longitudinal direction.

[0016] The rear transverse cross-section can correspond to, for example, an ellipse or the intersection of two non-concentric circles. In the description, this cross-section can be designed as an elliptical cross-section, but it can not be a perfect ellipse. The invention is particularly beneficial when the circular cross-section assembly holes of the two elements are misaligned and only partially intersect, i.e. in the case of a visible opening between the front element and the rear element having an "eye-shaped shape" or a non-empty intersection of non-concentric circles.

[0017] The outer surface of the sleeve transitions from its last cross-section to its first cross-section. More particularly, the outer surface of the sleeve transitions from an elliptical cross-section in the rear portion of the sleeve to a circular cross-section in the front portion of the sleeve. Along the longitudinal axis of the sleeve, from the rear of the sleeve to the front of the sleeve, the difference between the major axis and the minor axis gradually decreases until the major axis and the minor axis are equal and form the diameter of a circle. This allows the rear portion of the sleeve to be easily introduced into the open intersection between the misaligned through holes of the first and second elements. As the connection system is further introduced through the through holes, in particular as the threaded bolt advances towards the rear portion of the housing, the transition of the outer surface of the sleeve to a circular shape facilitates the alignment of the through holes of the first and second elements, so that the first and first elements can be aligned after the installation of the connection system according to the invention.

[0018] In some embodiments, the posterior transverse cross-section has an outer shape with one or two common vertices having the same radius as the circular anterior transverse cross-section.

[0019] Together with the fastening element, the threaded bolt transmits axial loads. The threaded bolt also generates the force required for assembly as it rotates within the fastening element, which can be, for example, a nut. The connecting element is another component that holds the system in place and transmits axial loads. The connecting element reacts to the installation force applied by the threaded bolt.

[0020] The sleeve transfers the shear load. During assembly of the connection system, the sleeve aligns the elements to be connected as it travels with the threaded bolt.

[0021] The housing provides the space required to house the sleeve. Furthermore, the interior surface of the housing allows for alignment, as the interior surface may correspond to the exterior shape of the sleeve. In other embodiments, the interior surface of the housing corresponds to a surface of revolution about the longitudinal axis of the apex of the sleeve, such that once the sleeve is in the assembled configuration, the sleeve can freely rotate within the housing while the apex of the sleeve is in contact with the housing.

[0022] The present invention provides various advantages:

[0023] Correction of considerable offsets between through-holes, for example drilled holes, in the components to be connected.

[0024] During assembly and disassembly, loads are gradually transferred between the connected components, for example due to the weight of the structure. This gradual transfer is achieved through controlled tightening. When a sleeve is inserted into the through-holes of the parts to be connected, the load on the connection increases as the bolt and sleeve advance. Thus, as the connection is tightened and loosened by the sleeve, the through-holes gradually align.

[0025] -Can be used for multiple assembly and disassembly cycles.

[0026] - Reduction of assembly time required for pre-positioning of elements to be connected. The invention saves time and tools, since it would otherwise be necessary to precisely align the holes in the parts to be connected beforehand.

[0027] - The assembly is lightweight compared to door opening and closing elements such as hinges, locking bolts etc.

[0028] - Easy assembly and disassembly, since it is not necessary to access the two sides of the connection system, since the invention can be accessed via the front without having to access its rear part.

[0029] -Easy to inspect / maintain / repair.

[0030] -Can be used in combination with other complementary solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the following description, certain specific exemplary embodiments and aspects of the present invention are described with reference to the accompanying drawings.

[0032] Figure 1 A first exemplary embodiment of a longitudinal section through a first element and a second element to be connected and the connection system in the assembled position is shown.

[0033] Figures 2A-2D Shown are a longitudinal section through a sleeve of a connection system according to the invention and three different transverse sections through the same sleeve.

[0034] Figures 3A-3E Shown is a longitudinal section through a first element and a second element to be connected and a second exemplary embodiment of a connecting system according to the invention. Figures 3A-3E The assembly sequence of the exemplary embodiment of the connection system is shown.

[0035] Figure 4 Shown is a longitudinal section through a first element and a second element to be connected and a third exemplary embodiment of the connection system in the assembled position.

[0036] Figure 5 Shown with Figures 3A-3E A perspective view of a corresponding example embodiment. DETAILED DESCRIPTION

[0037] These figures show various example embodiments of the connection system of the present invention.

[0038] The first element (1) is shown arranged in a front position, while the second element (2) is shown arranged in a rear position. Both elements (1, 2) have through holes (3) for their assembly.

[0039] The first element (1) and the second element (2) can be made of any material, such as metal, composite material, CFRP, etc.

[0040] The connection system shown includes the following parts.

[0041] The threaded bolt (4) passes through the through holes (3) in the first element (1) and the second element (2). The threaded bolt (4) comprises a rear longitudinal portion (4.1) and a front longitudinal portion (4.2).

[0042] The sleeve (5) is configured to be positioned concentrically around the threaded bolt (4) in at least the front longitudinal portion (4.2) of the threaded bolt (4). The sleeve (5) comprises an outer surface (5.1) that tapers towards the rear longitudinal portion (4.1) of the threaded bolt (4).

[0043] The housing (7) is connected to the second element (2) of the rear portion. The housing (7) comprises an inner face (7.1) in which the sleeve (5) is housed in its assembled position.

[0044] The fastening element (6) is screwed to the rear longitudinal portion (4.1) of the threaded bolt (4) for the attachment of the connection system.

[0045] The housing (7) is connected to the second element (2) of the rear portion using any connection means, such as riveting, adhesive bonding, etc.

[0046] Advantageously, the threaded bolt (4) is free to rotate within the sleeve (5). However, the sleeve and the threaded bolt (4) can be assembled to each other such that the sleeve is longitudinally connected to the threaded bolt (4) to be displaced with the threaded bolt towards or out of the housing (7). The sleeve and the threaded bolt (4) can be assembled to each other, for example, by means of a stop ring. This connection in particular facilitates the extraction of the sleeve from the housing when disassembling the connection system.

[0047] In the Figure 1 , the fastening element (6) forms a single piece with the housing (7). This example embodiment has the advantage of preventing the fastening element (6) from possibly falling into a difficult-to-access area of the aircraft, for example, and thus improving the safety and assembly convenience of the connection system.

[0048] More particularly, in the example embodiment shown, the fastening element (6) is located at the rear end of the housing (7). In this embodiment, the fastening element (6) is a nut. More particularly, the fastening element (6) corresponds to a nut embedded in the rear end of the housing (7).

[0049] In one example embodiment, the fastening element (6) is mounted on the housing (7) to allow a spherical rotation of the fastening element (6) relative to the housing (7). In particular, this allows the fastening element (6) to rotate spherically around two axes perpendicular to the longitudinal direction, but not around the longitudinal direction.

[0050] This allows the threaded bolt (4) to be introduced in an inclined position relative to the nominal introduction direction during the initial phase of assembly and, despite this inclination of the threaded bolt (4), to engage the threaded bolt (4) with the fastening element. This is beneficial when the through holes in the first element (1) and the second element (2) are not misaligned.

[0051] Figures 2A-2D A particular embodiment of the sleeve (5) of the connection system according to the application is shown. Various cross sections of such a sleeve (5) are shown in Figures 2A-2D .

[0052] Figure 2AA first longitudinal section through a plane comprising the longitudinal inlet of the sleeve is shown.The sleeve comprises a longitudinal bore (5.4) for accommodating a threaded bolt (4).

[0053] The width of the front part of the sleeve (5) is greater than the width of its rear part, thereby forming a head suitable for contacting the first element (1). In the front part of the sleeve (5), the sleeve is advantageously cylindrical. Thus, the front transverse section (5.5) has a circular shape.

[0054] The sleeve tapers towards its rear portion. The rear transverse section (5.3) of the sleeve has a generally oval shape.

[0055] This transition of the shape of the sleeve between the rear portion of the sleeve and the front portion of the sleeve is illustrated by the following successive transverse sections: said successive transverse sections comprising Figure 2B The transverse section AA, Figure 2C The transverse section BB and Figure 2D . While section CC has a circular outer shape, transverse sections BB and AA have outer shapes corresponding to the intersection of two misaligned circles. The difference in size between sections BB and AA represents the tapering shape of the sleeve. Between sections CC and BB, the outer surface (5.1) of the sleeve transitions from a circular cross-section to an elliptical cross-section, as shown in section BB.

[0056] As best illustrated by section AA, the connection system comprising the sleeve according to the invention allows easy introduction into a hole that is the intersection of a circular hole in a first element and a circular hole in a second element that are superimposed and not aligned.

[0057] The order of introduction of the connection system is Figures 3A-3E , wherein the third and fourth images of the assembly sequence show that the threaded bolt (4) has an inclination during its introduction. The installation of the fastening element (6) allows the threaded bolt (4) to have a certain degree of inclination while allowing the threaded bolt (4) to be screwed into the fastening element (6).

[0058] When the threaded bolt (4) advances towards the fastening element (6) at the rear of the connection system, centering is achieved by advancing the male sleeve (5) through the through hole (3) in the elements (1, 2) to be connected and the female housing (7). The threaded bolt and the elements (1, 2) to be connected are positioned in their nominal positions by the complementarity of the outer surface of the sleeve (5) and the inner surface of the housing (7).

[0059] also, Figure 4 The fastening element (6) shown comprises a curved front portion (6.1) that cooperates in this spherical movement.

[0060] In the example embodiment shown in the figures, the connection system shown can have a wear sleeve attached to the inner face (7.1) of the housing (7) to prevent wear of said inner face (7.1). Said wear sleeve is not shown in the figures.

[0061] In one example embodiment shown in the figures, the fastening element (6) is configured to be positioned in an extension of the rear end of the housing (7). Thus, the housing (7) and the fastening element (6) are configured so that the housing (7) is positioned longitudinally between the fastening element (6) and the rear second element (2). Thus, the fastening element (6) is an element independent of the housing (7).

[0062] As mentioned above, Figures 3A-3E The assembly sequence of the connection system is described.

[0063] In the first, Figure 3A In this figure, the front first element (1) and the rear second element (2) are not aligned; in other words, the respective through holes (3) of the front first element (1) and of the rear second element (2) do not have the same longitudinal axis and only partially coincide. If these through holes are of circular shape, the opening has an elliptical "eye shape" formed by the intersection of two misaligned circles. In the sequence shown, it can be seen that the housing (7) is connected to the rear second element (2). The threaded bolt (4), together with the sleeve (5), is inserted from the front into the opening formed by the intersection of the two through holes (3).

[0064] In the second, Figure 3B In this figure, the rear end of the threaded bolt (4) is in contact with the fastening element (6) and begins to be screwed into it. In the example embodiment shown, the distance between the rear end of the threaded bolt (4) and the rear end of the sleeve (5) is greater than the length of the housing (7). Thus, the length of the threaded bolt (4) is such that, when the rear end of the sleeve (5) is still outside the through hole (3) in the element (1, 2) to be connected, the threaded bolt (4) fits in the thread of the fastening element (6). Thus, the screwing action controls the longitudinal movement of the sleeve (5) through the through hole and, consequently, the axial force exerted thereby on the elements (1, 2) to be connected.

[0065] In the third, Figure 3C The sliding and deformation between the elements (1, 2) to be connected are shown. As mentioned above, the connection system makes it possible to incline the threaded bolt (4) with respect to the housing (7) in order to facilitate the introduction of the threaded bolt and its sleeve. The shape of the sleeve and of its elliptical rear portion also facilitates the introduction, since this corresponds to the general shape of the opening left by the intersection of the misaligned through holes in the elements (1, 2) to be connected.

[0066] In the fourth, Figure 3DIt can be seen that the sleeve (5) exerts a lateral force on the lateral sides of the first element (1) and of the second element (2) or on the housing 7. The through hole (3) of the second element (2) is thus aligned with the through hole (3) of the first element (1) of the front portion.

[0067] Finally Figure 3E The final configuration of the connection system in its assembled position is shown.

[0068] In both example embodiments, the inner face (7.1) of the housing (7) has a shape adapted to accommodate the outer face (5.1) of the sleeve (5) so that, once the connection system is assembled, the two elements fit together.

[0069] In particular, the front portion of the housing can comprise a tronco-conical portion. The front portion of the sleeve can also comprise a tronco-conical portion. In such embodiments, the inner face of the housing matches the outer face of the sleeve so that they can fit together perfectly and provide a perfect alignment of the portions.

[0070] During alignment, considerable pressure can be exerted on the edges of the through holes (3) in the elements (1, 2) to be connected. In order to prevent material wear, the connection system can comprise a wear sleeve (8), for example made of hard metal, which is housed in said through holes (3), as shown for example in Figure 4 .

[0071] Figure 4 and Figure 5 An example embodiment is shown in which the connection system comprises a retaining cap (9) connected to the fastening element (6), for example a nut. The retaining cap (9) comprises means for:

[0072] - preventing rotation of said fastening element (6) around the longitudinal axis of the threaded bolt (4), and

[0073] - limiting movement of said fastening element (6) along the longitudinal axis of the threaded bolt (4).

[0074] The retaining cap (9) thus both limits rotation of the fastening element (6) around the threaded bolt (4) and also limits longitudinal movement of the fastening element (6) relative to said threaded bolt (4). In a certain sense, the retaining cap (9) acts as a housing for the fastening element (6).

[0075] This arrangement has advantages, for example, when dismounting the connection system from the front of the system. When dismounting, the threaded bolt (4) is moved longitudinally towards the front of the connection system and at a predetermined moment stops being threaded with the fastening element (6). The retaining cap (9) acts as a housing for the fastening element (6) and thus prevents said fastening element (6) from falling into, for example, inaccessible areas of the aircraft.

[0076] According to the example embodiment illustrated in the figures, the retaining cap (9) comprises a first surface (9.3) intended to be placed, in the assembled position, perpendicular to the longitudinal axis of the threaded bolt (4). Said first surface (9.3) comprises a first hole for housing the fastening element (6). In some embodiments, the shape of said first hole is complementary to the non-circular shape of the fastening element (6). Thus, the retaining cap (9) prevents the fastening element (6) from rotating around the longitudinal axis of the threaded bolt (4). The hole in the first surface of the retaining cap can house a portion of the fastening element and a rear end portion of the threaded bolt within said fastening element.

[0077] In the example embodiment illustrated, the retaining cap (9) also comprises at least one second surface (9.2) intended to be placed, in the assembled position, parallel to the longitudinal axis of the threaded bolt (4). This second surface (9.2) partially covers longitudinally the fastening element (6) and the rear portion of the housing (7). The second surface (9.2) is joined to the first surface (9.3).

[0078] In the example embodiment illustrated, as can be seen in Figure 5 The retaining cap (9) comprises four second surfaces (9.2). Alternatively, the retaining cap (9) can comprise a single continuous second surface (9.2) around the threaded bolt (4).

[0079] The second surface (9.2) comprises at least one second hole (9.1) for the insertion of a through element for connecting the retaining cap (9) to the housing (7). A screw can be inserted in said second hole (9.1), the tip of the screw being located in the housing (7). Thus, the retaining cap (9) is connected to the housing (7), preventing longitudinal movement and rotation between the two elements.

[0080] In the example embodiment illustrated in the figures, the housing (7) also comprises a recess (7.2) facing the second hole (9.1) in the retaining cap (9), for the insertion of the screw mentioned above.

[0081] In Figure 4 and Figure 5In the example embodiment shown, there is a gap (not shown) between the fastening element (6) and the retaining cap (9). The gap allows the fastening element (6) to still be permitted to rotate spherically, i.e. around two axes orthogonal to the longitudinal axis. As mentioned above, this allows the threaded bolt (4) and the sleeve (5) to be tilted in the initial phase of assembly, thereby allowing assembly when the holes in the first element (1) and the second element (2) are not aligned. The spherical rotation of the fastening element (6) also makes it possible to connect the threaded bolt (4) and the fastening element (6) even when the threaded bolt (4) is tilted.

[0082] Finally, in the example embodiment shown, the fastening element (6) comprises a front region whose radial dimension is greater than the radial dimension of the rear region positioned in alignment with the hole in the first surface (9.3). In particular, the curved front portion (6.1) is larger than the hole in the transverse direction. This facilitates retaining the fastening element (6) in the retaining cap (9) once the fastening element (6) is separated from the threaded bolt (4). This also provides a surface for contact between the fastening element (6) and the housing (7) which is suitable for the case in which the threaded bolt (4) and the fastening element (6) are tilted. Figure 4 Figure 5 In the example embodiment shown, the fastening element (6) comprises a front region whose radial dimension is greater than the radial dimension of the rear region positioned in alignment with the hole in the first surface (9.3). In particular, the curved front portion (6.1) is larger than the hole in the transverse direction. This facilitates retaining the fastening element (6) in the retaining cap (9) once the fastening element (6) is separated from the threaded bolt (4). This also provides a surface for contact between the fastening element (6) and the housing (7) which is suitable for the case in which the threaded bolt (4) and the fastening element (6) are tilted.

[0083] The invention is not limited to the specific embodiments disclosed herein as examples. The invention also includes other embodiments which are not explicitly described herein, which can comprise various combinations of the features described herein.​

Claims

1. A connection system for the connection between at least a first element (1) of front portion and a second element (2) of rear portion, each of the elements (1, 2) comprising a through hole (3), the connection system comprising: - a threaded bolt (4) having a longitudinal axis and configured to pass at least partially through the through holes (3) in the first element (1) and in the second element (2), the threaded bolt (4) comprising a rear longitudinal portion (4.1) having at least one threaded section and a front longitudinal portion (4.2), - a sleeve (5): • configured to be positioned concentrically around the threaded bolt (4) at least in the front longitudinal portion (4.2) of the threaded bolt, • configured to be introduced in the through holes (3) together with the threaded bolt (4) while allowing the threaded bolt (4) to rotate inside the sleeve (5), • tapered towards the rear longitudinal portion (4.1) of the threaded bolt, - a housing (7) configured to be connected to the second element (2) of rear portion and adapted to house the sleeve (5) in an assembled position of the connection system, and - a fastening element (6) configured to be threadedly connected to the rear longitudinal portion (4.1) of the threaded bolt (4), characterized in that the sleeve (5) has an outer surface (5.1) comprising: - a rear transverse section (5.3) proximate to the rear longitudinal portion (4.1) of the threaded bolt, having a major axis and a non-collinear minor axis shorter than the major axis.

2. The connection system of claim 1, wherein, the sleeve (5) has an outer surface (5.1) comprising a front transverse section (5.5) proximate to the front longitudinal portion (4.2) of the threaded bolt, having a circular shape.

3. The connection system of claim 2, wherein, the diameter of the front transverse section (5.5) of the front longitudinal portion (4.2) is greater than the major axis of the rear longitudinal portion (4.1).

4. The connection system according to any of the preceding claims, characterized in that the sleeve (5) is connected to the threaded bolt (4) to longitudinally displace together with the threaded bolt (4).

5. The connection system according to any of the preceding claims, characterized in that, an inner face (7.1) of the housing (7) has a conical shape adapted to house the outer surface (5.1) of the sleeve (5) in any angular position around the longitudinal axis.

6. The connection system according to any of the preceding claims, characterized in that the distance between the rear end of the threaded bolt (4) and the rear end of the sleeve (5) is equal to or greater than the length of the housing (7).

7. The connection system according to any of the preceding claims, characterized in that the fastening element (6) is located at the rear end of the housing (7).

8. The connection system according to any of the preceding claims, characterized in that the fastening element (6) is a nut.

9. The connection system according to any of the preceding claims, characterized in that the fastening element (6) is attached to the housing (7) so that the longitudinal displacement of the fastening element (6) relative to the housing (7) is limited.

10. The connection system according to any of the preceding claims, characterized in that the fastening element (6) is mounted on the housing (7) to allow a spherical rotation of the fastening element (6) relative to the housing (7).

11. The connection system according to any of the preceding claims, characterized in that The fastening element (6) comprises a curved front portion (6.1).

12. The connection system according to any of the preceding claims, characterized in that The connection system comprises a retaining cap (9) adapted to be connected to the housing (7), the retaining cap (9) comprising means for: - preventing the fastening element (6) from rotating around the longitudinal axis of the threaded bolt (4), and - limiting the movement of the fastening element (6) along the longitudinal axis of the threaded bolt (4).

13. The connection system of claim 11, wherein, The retaining cap (9) comprises a first surface (9.3) intended, in the assembled position, to be placed perpendicularly to the longitudinal axis of the threaded bolt (4) and comprising a first non-circular hole for accommodating the fastening element (6).

14. The connection system according to claim 11 or 12, characterized in that The retaining cap (9) comprises at least one second surface (9.2) intended, in the assembled position, to be placed parallel to the longitudinal axis of the threaded bolt (4) so that the second surface (9.2) partially covers longitudinally the fastening element (6) and a rear portion of the housing (7), the second surface (9.2) comprising at least one second hole (9.1) for the insertion of a through element for connecting the retaining cap (9) to the housing (7).

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