GB2620963A

GB2620963A - A method of installing a fastener

Info

Publication number: GB2620963A
Application number: GB2211000.1A
Authority: GB
Inventors: Attwell Jack
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2024-01-31
Also published as: GB202211000D0

Abstract

The method of installing a fastener (120, Figure 9) uses an engagement tool 100 having first 101 and second 102 arms. The method includes arranging the first and second arms either side of a fastener head 121 of the fastener to hold the fastener in a first configuration. Then flexing the first arm relative to the second arm to increase a distance between the first arm and the second arm and release the fastener in a second configuration. An assembly includes a fastener having a fastener head, and an engagement tool for engaging the head. The tool has first and second arms with first and second engagement means 111, 112. The engagement means engage the head so that it is removably fixed between the arms in a first configuration. The first arm is configured to flex relative to the second arm to disengage the two engagement means from the head in a second configuration. The tool may include a third arm 108 positioned between, and extending parallel to, the two arms. An end portion of the third arm engages an end face of the fastener head. The tool may comprise plastics and may be used for aircraft assembly.

Description

A METHOD OF INSTALLING A FASTENER

FIELD OF THE INVENTION

[0001] The present invention relates to a method of installing a fastener, an assembly, and an aircraft comprising the assembly.

BACKGROUND OF THE INVENTION

[0002] Limited access to the fastener hole of a component can produce difficulties in assembly. There are various tools that may be adapted to grip a fastener so as to help guide it into its designated fastener hole, however they all have their respective disadvantages. For example, long-nosed pliers may be used. However, these can damage the protective coating on the fasteners, whilst the size and pivoting action required to open and close the jaws creates practical limits on its use in enclosed spaces. Magnetic pickup tools (also known as magnetic reach tools) may be useful for inserting steel fasteners but are not suitable for fasteners made from non-magnetic materials such as aluminium and titanium.

SUMMARY OF THE INVENTION

[0003] A first aspect of the invention provides a method of installing a fastener, comprising: an engagement tool having first and second arms; the method comprising: arranging the first and second arms either side of a fastener head of a fastener to hold the fastener in a first configuration; flexing the first arm relative to the second arm to increase a distance between the first arm and the second arm and release the fastener in a second configuration.

[0004] As such, passive actuation of the engagement tool is provided that selectively engages and disengages a fastener. This allows an engagement tool to place a fastener into a tight space, e.g. a hole, where otherwise it is not practical to insert the fastener.

[0005] The first arm may include a first recess for engaging a first portion of the fastener head; and the second arm includes a second recess for engaging a second portion of the fastener head opposite the first portion; wherein the fastener is held between the first and second recesses in the first configuration. The recesses help to increase engagement to the fastener, and thereby prevent the fastener from premature disengagement of the engagement tool [0006] The engagement tool may comprise a third arm positioned between, and extending parallel to, the first and second arms, wherein an end portion of the third arm is configured to engage an end face of the fastener head.

[0007] With this arrangement, the third arm is able to support the fastener and help to prevent the fastener slipping without restricting the flexure of each of the first and second arms.

[0008] A component having a hole, and a jig having a through-hole, may be provided. The method may comprise moving the jig to the component such that the through-hole of the jig aligns with the hole in the component; and extending the engagement tool through the through-hole of the jig to insert the fastener into a hole of the component.

[0009] With this arrangement, the jig restricts access to the hole in the component.

[0010] The method may comprise pressing the engagement tool against the component to generate a bending stress in the first and/or second arm so as to flex the first arm relative to the second arm.

[0011] With this arrangement, the engagement tool is able to use the surface of the component react against and thereby move the arms apart to disengage the fastener. The arrangement requires no rotation of the engagement tool.

[0012] The component may be a first component, and the method may comprise clamping a second component to the first component with a clamp, wherein the jig is attached to the clamp With this arrangement, there is limited access to the hole in the component(s) as the clamp is required to remain in position during assembly.

[0013] The method may comprise locating the jig at a drilling location on the first component; drilling the hole in the first component through the jig; and inserting the fastener into the hole of the first component, wherein the jig is maintained in the drilling position whilst drilling the hole and inserting the fastener. With this method, one-way assembly is achieved, which can reduce assembly time by mitigating the need to deburr or otherwise clean the components before they are clamped together for fastening.

[0014] A second aspect of the invention provides an assembly comprising: a fastener having a fastener head; and an engagement tool for engaging the fastener head, the engagement tool comprising a first arm having a first engagement means and a second arm having a second engagement means, the first and second engagement means arranged to engage the fastener head so that the fastener head is removably fixed between the first and second arms in a first configuration; wherein the first arm is configured to flex relative to the second arm so as to disengage the engagement means from the fastener head in a second configuration.

[0015] The engagement tool is able to passively engage and disengage from a fastener such that remote positioning and depositing of a fastener is possible.

[0016] The first engagement means may be a first recess for engaging a first portion of the fastener head, and the second engagement means may be a second recess for engaging a second portion of the fastener head opposite the first portion.

[0017] The recesses help to increase engagement to the fastener, and thereby prevent the fastener from premature disengagement of the engagement tool.

[0018] The assembly may comprise a third arm positioned between, and extending parallel to, the first and second arms, wherein an end portion of the third arm is configured to engage an end face of the fastener head.

[0019] With this arrangement, the third arm is able to support the fastener and help to prevent the fastener slipping without restricting the flexure of each of the first and second arms.

[0020] An end portion of the first and second arms may be tapered such that the distance between the end portions of the first and second arms increases towards a tip end of the first and second arms.

[0021] With this arrangement, bending of the first and second arms may be more easily achieved (e.g. a lower force applied) when the engagement tool is pressed against a component.

[0022] The engagement tool may comprise plastic. Plastic is a readily available material typically has material properties suitable for engaging the fastener without damaging it and suitable for allowing elastic bending of the arms at a relatively low stress.

[0023] The first arm and the second arm may be formed of a material having a bending modulus of less than 10 GPa, and preferably less than 5 GPa. The first arm and the second arm may be formed of a material having a bending modulus of more than 0.1 GPa, and preferably more than 0.5 GPa.

[0024] The assembly may comprise a component having a hole for inserting the fastener; a jig abutting the component, the jig having a through-hole extending through to the hole of the component; wherein the engagement tool is configured to extend through the through-hole of the jig and insert the fastener into the through-hole of the component.

[0025] With this arrangement, the jig provides limited access to the through-hole of the component that may necessitate the use of said engagement tool.

[0026] The engagement tool may be arranged such that pressing the first and second arms against the component is configured to generate a bending stress in the first and second arms so as to flex the first arm relative to the second arm [0027] With this arrangement, the engagement tool is able to react against the surface of the component to move the arms apart, and thereby selectively disengage the fastener.

[0028] The component may be a first component and the hole may be a through-hole. The assembly may comprise a second component abutting the first component, and a clamp having a first jaw and a second jaw clamping the first and second components together, and wherein the jig is attached to the clamp, and the through-hole of the jig is aligned with the through-hole of the first component.

[0029] With this arrangement, the jig is fixed in position relative to the clamp. The jig therefore cannot be moved without removing the clamp.

[0030] A robot end effector may be coupled to the clamp [0031] The assembly may be an aircraft assembly, the first component may be a rib web of an aircraft wing, and the second component may be a rib foot of an aircraft wing or a rib post of an aircraft wing.

[0032] Aircraft assemblies typically include many fasteners in difficult locations to reach, and where it is important each fastener is accounted for. This is particularly the case in the wing box of an aircraft.

[0033] A further aspect of the invention provides an aircraft comprising the assembly of the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments of the invention will now be described with reference to the accompanying drawings, in which: [0035] Figure 1 shows an aircraft; [0036] Figure 2 shows the wing box extending along a wing; [0037] Figure 3 shows part of a cross-section of the wing box; [0038] Figure 4 shows a perspective view of the upper cover, [0039] Figure 5 shows an automated clamp; [0040] Figure 6 shows the automated clamp attached to a robot, [0041] Figure 7 shows a close-up view of the assembly of a rib web and rib post; [0042] Figure 8 shows a first example of an engagement tool; [0043] Figure 9 shows a perspective view of a fastener; [0044] Figure 10 shows a cross-section of the engagement tool; [0045] Figure 11 shows a first step in the insertion of a fastener using the engagement tool; [0046] Figure 12 shows a second step in which the fastener is inserted into a hole; [0047] Figure 13 shows a third step in which the engagement tool is disengaged from the fastener; [0048] Figure 14 shows a fourth step in which the engagement tool is withdrawn from the jig; [0049] Figure 15 shows a second example of an engagement tool; [0050] Figure 16 shows a first step in the insertion of a fastener using the engagement tool, [0051] Figure 17 shows a second step in which the fastener is inserted into a hole, [0052] Figure 18 shows a third step in which the engagement tool is disengaged from the fastener, [0053] Figure 19 shows a fourth step in which the engagement tool is withdrawn from the jig.

DETAILED DESCRIPTION OF EMBODIMENT(S)

[0054] Figure 1 shows an aircraft 1 with port and starboard wings 2, 3. Each wing 2, 3 has a cantilevered structure with a length extending in a generally spanwise direction 42 from a root to a tip (indicated on Figure 3), the root being joined to an aircraft fuselage 4. The wings 2, 3 are similar in construction so only the starboard wing 3 will be described in detail with reference to Figures 2 and 3.

[0055] The main structural element of the wing 3 is a wing box that may be formed by upper and lower covers 21, 22 and front and rear spars 16, 17. The covers 21, 22 and spars 6, 7 may each be formed of Carbon Fibre Reinforced Polymer (CFRP) laminate components. Each cover 21, 22 comprises a panel assembly and may have a curved aerodynamic outer surface (e.g. the upper surface of the upper cover 21 and the lower surface of the lower cover 22) over which air flows during flight of the aircraft 1. Each cover 21, 22 has an inner surface carrying a series of stiffeners 18 extending in the spanwise direction 42 (only some of the stiffeners 18 are labelled so as to improve the clarity of the figures). Each stiffener 18 is joined to one cover 21, 22 but not the other.

[0056] The wing box 20 may have a plurality of transverse ribs 10, each rib 10 being joined to the covers 21, 22 and the spars 16, 17. The ribs 10 may include an inner-most inboard rib 10a located at the root of the wing box 20, an outer-most rib 10c at the tip of the wing box 20, and one or more ribs 10b between the inner-most and outer-most ribs 10a, 10c. The inner-most rib 10a may be an attachment rib which forms the root of the wing box 20 and is joined to a centre wing box 19 within the body of the fuselage 4. Each rib 10a, 10b, 10c may connect the upper cover 21 to the lower cover 22. The stiffeners 18 may pass through rib recesses 11 in the ribs 10b.

[0057] Figure 3 shows a cross sectional partial side view of a forward end region of the wing 3 of the aircraft I. In the illustrated example, the wing 3 comprises a spar-cover 30 comprising the upper cover 21 and the front spar 16. However, it will be appreciated that in other examples the spar and cover may be separate. The spar-cover 30 includes a lower spar flange 33. The spar-cover 30 is an integrally formed, monolithic component comprising the upper cover 21, the front spar 16, and the lower spar flange 33. The lower spar flange 33 acts as an attachment flange for mounting with the lower cover 22. The spar-cover 30 comprises fibre reinforced matrix composite laminate material, such as carbon fibre reinforced polymer. As can be seen from Figure 3, the spar-cover 30 is substantially Z-shaped. The rear spar 17 (not shown in Figure 3) may be substantially C-shaped with upper and lower attachment flanges for joining to the upper and lower covers 21, 22 respectively.

[0058] The rib 10 shown in Figures 3 and 4 extends in a chordwise direction of the wing 3. The rib 10 extends between the front spar 16 and the rear spar 17, and between the upper cover 21 and lower cover 22. The rib 10 is joined to the front spar 16 by a rib post 60. The rib post 60 at the forward end attaches the rib 10 to the front spar 16. A corresponding rib post 60 at the rearward end of the rib 10 attaches the rib to the rear spar 17. The rib 10 comprises fibre reinforced matrix composite laminate material, such as carbon fibre reinforced polymer (CFRP). Although components are described herein as being formed from fibre reinforced matrix composite laminate material, such as carbon fibre reinforced polymer, it will be understood that alternative materials may be used.

[0059] The rib 10 includes a rib web 52. The rib web 52 defines the general plane of the rib 10. Rib feet 53 mount the rib 10 to the upper and lower covers 21, 22.

[0060] The rib feet 53 may be integrally formed with the upper and/or lower covers 21, 22, such as shown in Figure 4 in relation to the upper cover 21. The rib feet 53 are attached to the rib web 52 by fasteners 120, e.g. by bolts and/or rivets. The rib feet 53, stiffeners 18 and other components may be attached or co-cured to the upper and lower covers 21, 22 in various configurations.

[0061] The rib post 60 is attached to the rib web 52 by fasteners 120, e.g. bolts and/or rivets.

[0062] Figure 4 is an example showing part of the upper cover 21 including three stiffeners 18. The rib web 52 is coupled to the upper cover 21 by a plurality of CFRP laminate rib feet 53 (six of such rib feet being shown in Figure 4).

[0063] The rib foot 53 shown in Figure 4 is co-cured to the stiffener 18 and inner surface of the upper cover 21. This co-cured joint (without bolts) between the rib foot 53 and the upper cover 21 means that no drilled bolt holes need to be provided in the upper cover 21.

[0064] Fastening the rib post 60 to the rib web 52 will now be described, although it will be appreciated the method may equally apply to attachment of the rib foot 53 to the rib web 52.

[0065] Figure 5 shows an end effector 70a in the form of an automated clamp 70. The clamp 70 has a clamp frame 71, which in the illustrated example is generally U-shaped. The clamp frame 71 has a first arm 72 and a second arm 73. The arms 72, 73 are generally parallel. A robot end effector connector 74 may be coupled to the clamp frame 71. The end effector connector 74 may provide physical arid electrical coupling of the clamp 70 to a robot 90 (see Figure 6) as part of a clamp system.

[0066] The clamp 70 has clamp jaws for clamping either side of a workpiece The clamp jaws include a first jaw 76 located towards a proximal end 78 of the first arm 72, and a second jaw 77 located towards a proximal end 79 of the second arm 73. The arms 72, 73 are joined together at their distal ends 80 The distance between the arms 72, 73 may be sufficient to clear around rib post 60 (or rib feet 53) of the rib 10 during positioning of the clamp 70, with a margin for robot position tolerance and fixture position tolerance.

[0067] The first jaw 76 may be fixed (i.e. not moving) with respect to the clamp frame 71. The second jaw 77 may be moveable towards and away from the first jaw 77 by a motor 81 to open and close the jaws 72, 73 around a component. For example, Figure 5 shows the second jaw 77 mounted on a linear rail 82 for linear movement of the second jaw 77 with respect to the clamp frame 71 to open and close the clamp jaws 76, 77.

[0068] Figure 5 shows that the clamp jaws 76, 77 connected to end surfaces 72a, 73a of the arms 72, 73, although it will be appreciated that the clamp jaws 76, 77 may be attached to the side surfaces 72b, 73b of the arms 72, 73.

[0069] The first clamp jaw 76 is configured to receive a tool module 95 and has a through-hole 84 (See Figure 7) through which various tools can be inserted, e.g. a drilling tool and a fastening tool. The tool module 95 may be manually operated or connected to a second robot (not shown) [0070] The clamp 70 is used to temporarily clamp the rib web 52 to the rib post 60. The tool module 95 may then be positioned on the clamp 70 such that a tool extends through the through-hole 84 of the first clamp jaw 76. The clamp 70 can thereby provide access to the workpiece (e.g. the rib web 52, rib foot 53, or rib post 60) so as to drill and fasten the rib web 52 to the rib post 60.

[0071] Assembling the wing box 20 in a 'one-way assembly' is desirable. One-way assembly involves the drilling and fastening of an assembly without an intermediate step of disassembly after drilling and prior to fastening. If a clamping force is not applied then one way assembly is typically not practical, as inter-laminar burring may occur during drilling and necessitate the disassembly and cleaning before reassembly and final fastening. As such, once drilling of the fastener hole has completed, the clamping load on the components is sustained whilst subsequent fastening takes place. The clamp 70 can hold the rib web 52 to the rib post 60 whilst both the drilling and fastening operations are completed.

[0072] The through-hole 84 in the clamp 70 helps in the alignment of the tool, however this also gives rise to various challenges, as will be discussed below.

[0073] Figure 7 shows an example in which the rib web 52 and rib post 60 are clamped together by the clamp 70, and in which a through-hole 86 has been drilled that extends through the rib web 52 and rib post 60. The through-hole 86 is located between a through-hole 84 of the first jaw 76 and a hole 85 of the second jaw 77. The hole 85 of the second jaw 77 may be a blind hole or a through-hole.

[0074] Installing the fastener 120 in the hole with the fastening module to fasten the clamped rib web and integrated rib foot web is completed prior to removing the clamping load so that one-way assembly can be achieved. However, the first clamp jaw 76 (and, in particular, the through-hole 84 in the first clamp jaw 76) restricts access to the through-hole 86 in the rib post 60. This presents various challenges in depositing a fastener 120.

[0075] Figure 8 shows a first example of an engagement tool 100. The engagement tool 100 includes a first arm 101 having a first engagement means 111 and a second arm 102 having a second engagement means 112. The arms 101, 102 are parallel to a central axis 115 of the engagement tool 100. The engagement means 111, 112 are arranged to engage a fastener 120 (for example, as shown in Figure 9), and in particular a fastener head 121 of the fastener 120, so as to releasably fix the fastener head 121 between the first and second arms 101, 102.

[0076] Figure 9 shows an example of a fastener 120. In this example, the fastener 120 is a bolt although it will be appreciated the fastener 120 may be any suitable fastener. The fastener 120 includes a fastener head 121 and a fastener shank 122 extending from the fastener head 121. An axis 125 of the fastener 120 extends through the fastener head 121 and fastener shank 122. The fastener head 121 shown in Figure 9 has a hexagonal cross-section, although it will be appreciated that the fastener head 121 may have any suitable cross-sectional shape, such as square or circular. The cross-section of the fastener head 121 may be constant along the axis 125 of the fastener 120 or may vary. For example, the fastener head 121 may be tapered.

[0077] Figure 8 shows the engagement means 111, 112 as respective first and second recesses 111a, 112a formed in the respective first and second arms 101, 102, in which the first recess 1 1 lais arranged to engage a first portion 124a of the fastener head 121 and the second recess 112a is arranged to engage a second portion 124b of the fastener head 121, such as shown for example in Figures 10 and 15, with the axis 115 of the engagement tool 100 and axis 125 of the fastener 120 generally parallel and aligned. The engagement means 111, 112 may be profiled to match the profile of the portions 124a, 124b of the fastener head 121 to which they engage. The first and second portions 124a, 124b of the fastener head 121 may be opposing portions 124a, 124b of the fastener head 121.

[0078] The first and second arms 101, 102 may be attached at a base portion 103, so as to form a generally U-shaped engagement tool 100. A rod 105 may extend from the base portion 103 of the engagement tool 100. The rod 105 may be attachable to an end effector 70a, a jig, or employ any other suitable means that allow the engagement tool 100 to be moved. For example, the engagement tool 100 may be hand-held.

[0079] Figure 10 shows the cross-section A-A indicated in Figure 8, and in which the rod 105 is shown as generally cylindrical in shape, although it will be appreciated the rod 105 may be any suitable shape. The recesses 111a, 112a have vertex's 111b, 112b extending into the respective arms 101, 102, and in particular extending outwards from an inner surface 113, 114 of the arms 101, 102, however the recesses 111a, 112a may have any suitable shape so as to suitably engage to the portions 124a, 124b of the fastener head 121.

[0080] A method of using the engagement tool 100 to selectively engage a fastener 120 will now be described with reference to Figures 11 to 14.

[0081] In a first step, shown in Figure 11, the first and second arms 101, 102 are arranged either side a fastener head 121 of the fastener 120 so as to hold the fastener 120 in a first configuration. In the first configuration, the fastener 120 is substantially fixed with respect to the engagement tool 100.

[0082] In a second step, shown in Figure 12, the engagement tool 100, with the fastener 120 fixed to the engagement tool 100, is moved through the through-hole 145 of a jig 140 (for example a clamp 70), and towards a material stack 130. The material stack 130 comprises a first component 131 and a second component 132 clamped together. The fastener 120 is inserted into a through-hole 134 of the material stack 130, for example the through-hole 86 referred to earlier that extends through the rib web 52 and rib post 60, or the rib web 52 and rib foot 53 [0083] In a third step, shown in Figure 13, the engagement tool 100 is rotated in a plane perpendicular to the axis 125 of the fastener 120. In particular, the engagement tool 100 is rotated through a plane extending through the first and second arms 101, 102 of the engagement tool 100, such as shown in Figure 13.

[0084] As a result of rotating the engagement tool 100, for example by rotating the rod 105, the first arm 101 is flexed (i.e. bent) relative to the second arm 102 into a second configuration. In particular, the first arm 101 is able to rotate with the rod 105, whilst the second arm 102 is prevented from rotating moving by the fastener 120 engaged in the through-hole 134. This increases the distance between the first arm 101 and the second arm 102 so that the fastener 120 can disengage from the engagement means 111, 112.

[0085] In a fourth step, shown in Figure 14, the engagement tool 100 is withdrawn from the fastener 120, and withdrawn from the through-hole 145 of the jig 140, leaving the fastener UO installed in the through-hole 134 of the material stack 130. As the engagement tool 100 withdraws from the fastener 120, the arms 101, 102 return to the first configuration [0086] In order to increase the flexibility of the arms 101, 102, the engagement means 111, 112 is preferably located towards an end portion 106, 107 of each arm 101, 102, i.e. distal from the base portion 103 so as the increase the lever arm length, such as shown in Figure 8. The end portions 106, 107 of the arms 101, 102 may each have a cross-sectional area greater than a cross-sectional area of the arms 101, 102 inboard (i.e. towards the base portion 103). Providing a larger cross-sectional area at the end portions 106, 107 may provide sufficient thickness for the recesses 111a, 112a to be built into the arms 101, 102, whilst providing the respectively small cross-sectional area inboard of the end portions 106, 107 may ensure the arms 101, 102 are sufficiently flexible so as to move between the first and second configurations.

[0087] In the previous example, the engagement means 111, 112 are recesses H I a, 112a, however it will be appreciated that other engagement means may be used. For example, the engagement means 1H, 112 may comprise flat surfaces that rely on frictional engagement to engage the fastener 120 [0088] The engagement tool 100 may include a third arm 108 positioned between, and extending parallel to, the first and second arms 101, 102, such that the third arm 108 is spaced from the first and second arms 101, 102. The third arm 108 engages an end face 127 of the fastener 120 so as to assist in maintaining the fastener head 121 at the engagement means 111, 112, whilst preserving the flexibility of the first and second arms 101, 102 by not connecting the first and second arms 101, 102. Consequently, the engagement means 111, 112, such as the recesses 111a, 112a, may be reduced in size in comparison to examples without a third arm 108.

[0089] The engagement tool 100, and in particular the first and second arms 101, 102, may be formed of plastic. An engagement tool 100 formed of plastic may be easy to manufacture than other alternative materials, for example the engagement tool 100 may be formed by additive manufacturing. The engagement tool 100 may be integrally formed so as to have no mechanically coupled parts In [0090] In order to provide a material with a balance between stiffness and flexibility, the material may have a bending modulus of less than 10 GPa and greater than 0.1 GPa, and preferably a bending modulus less than 5 GPa and greater than 0.5 GPa [0091] Figure 15 shows an example of an engagement tool 100a according to a second example. The second example is substantially the same as the first example, and so only those features different to the first example will be described in detail.

[0092] In the second example, the engagement tool 100 is arranged such that pressing the first and second arms 101, 102 against the component generates a bending stress in the first and second arms 101, 102 so as to flex the first arm 101 relative to the second arm 102 [0093] An example of the engagement tool 100 is shown in Figure 15, in which the end portions 106, 107 of the arms 101, 102 are shown to have a tapered profile, with the distance between the end portions 106, 107 of the first and second arms 101, 102 increasing towards a tip end 106a, 107a of the first and second arms 101, 102. The inner surface 113, 114 of the first and second arms at the end portions 106, 107 may be chamfered, such as shown in Figure 15, although it will be appreciated the inner surface 113, 114 may be curved or otherwise profiled to encourage the first and second arms 101, 102 to flex relative to each other.

[0094] A method of using the engagement tool 100a to selectively engage a fastener 120 will now be described with reference to Figures 16 to 19 [0095] In a first step, shown in Figure 16, the first and second arms 101, 102 are arranged either side a fastener head 121 of the fastener 120 so as to hold the fastener 120 in a first configuration. In the first configuration, the fastener 120 is substantially fixed with respect to the engagement tool 100.

[0096] In a second step, shown in Figure 17, the engagement tool 100a, with the fastener 120 fixed to the engagement tool 100a, is moved through the through-hole 145 of a jig 140 (for example a clamp 70), and towards a material stack 130. The material stack 130 comprises a first component 131 and a second component 132 clamped together. The fastener 120 is inserted into a through-hole 134 of the material stack 130, for example the through-hole 86 referred to earlier that extends through the rib web 52 and rib post 60, or the rib web 52 and rib foot 53.

[0097] In a third step, shown in Figure 18, the engagement tool 100a is moved towards the material stack 130 so as to press against the first component 131. in particular, the engagement tool 100a is moved in a direction substantially parallel to the axis 125 of the fastener 120.

[0098] As a result of pressing the engagement tool 100a against the first component 131, the first arm 101 and second arm 102 are each flexed (i.e. bent) into a second configuration. In particular, movement of the first and second arms 101, 102 towards each other is prevented by the fastener head 121, however outward flexure of the arms 101, 102 is permittable due to the arms 101, 102 of the engagement tool 100a, in the first configuration, being spaced from the walls of the through-hole 145 of the jig 140. For example, the through-hole 145 of the jig 140 may have a diameter greater than that of the engagement tool 100a at the location of the arms 101, 102.

[0099] The flexure of the first and second arms 101, 102 increases the distance between the first arm 101 and the second arm 102 so that the fastener 120 can disengage from the engagement means 111, 112.

[0100] In a fourth step, shown in Figure 19, the engagement tool 100a is withdrawn from the fastener 120, and withdrawn from the through-hole 145 of the jig 140, leaving the fastener 120 installed in the through-hole 134 of the material stack 130. As the engagement tool 100a withdraws from the fastener 120, the arms 101, 102 return to the first configuration, [0101] In order to help and guide the first and second arms 101, 102 outwards, away from the fastener head 121, the arms 101, 102 may have a tapered profile, such as described previously. For example, the inner surface 113, 114 of the first and second arms at the end portions 106, 107 may be chamfered, such as shown in Figure 15.

[0102] The passive actuation of the above-mentioned examples provides a number of advantages over existing solutions, such as fewer moving parts. The materials suitable for providing the degree of elastic flexibility required to operate the above-mentioned engagement tools 100, 100a (e.g. plastic) also typically have a lower hardness than alternatives, such an metal long-nosed pliers, and therefore have a reduced hardness in relation to the fasteners 120 (and in particular a hardness less than the fasteners 120) ad therefore scratching and damage to the fasteners 120 is reduced. The fasteners 120 are also engaged between the first and second arms 101, 102 of the engagement tools 100, 100a by a force acting perpendicular to the axis 125 of the fastener 120, in comparison to a long-nosed plier (or similar pivotable device) which applies a force tangential to the axis 125 of the fastener 120.

[0103] The through-hole 145 in the jig 140 may be longer than the fastener 120, for example at least twice the length of the fastener 120, such that fastener 120 needs to be held as it is inserted through at least part of the through-hole 145 (i.e. the fastener 120 cannot be inserted into the through-hole 134 of the material stack 130 until the fastener 120 has been fully inserted into the through-hole of the jig 140, such that it is not possible to simply push the remaining portions of the fastener 120 into the through-hole 134).

[0104] The second example of the engagement tool 100a may be particularly useful in assemblies in which the through-hole 145 of the jig 140 restricts the degree that the engagement tool 100, 100a can be rotated through a plane extending through the first and second arms 101, 102 of the engagement tool 100, 100a (such as shown in the example of Figures 8 to 14).

[0105] The engagement tools 100, 100a may be particularly useful in applications in which other solutions are not possible For example, the fastener 120 may be nonmagnetic such that a magnetic reach tool or similar device cannot be used.

[0106] Where the word 'or' appears this is to be construed to mean 'and/or' such that items referred to are not necessarily mutually exclusive and may be used in any appropriate combination.

[0107] Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A method of installing a fastener, comprising: an engagement tool having first and second arms; the method comprising: arranging the first and second arms either side of a fastener head of a fastener to hold the fastener in a first configuration; flexing the first arm relative to the second arm to Increase a distance between the first arm and the second arm and release the fastener in a second configuration.
2 The method of claim 1, wherein: the first arm includes a first recess for engaging a first portion of the fastener head; and the second arm includes a second recess for engaging a second portion of the fastener head opposite the first portion; wherein the fastener is held between the first and second recesses in the first configuration.
3 The method of claim 1 or 2, wherein the engagement tool comprises a third arm positioned between, and extending parallel to, the first and second arms, wherein an end portion of the third arm is configured to engage an end face of the fastener head.
4 The method of any preceding claim, comprising: a component having a hole, and a jig having a through-hole; the method comprising: moving the jig to the component such that the through-hole of the jig aligns with the hole in the component; and extending the engagement tool through the through-hole of the jig to insert the fastener into the hole of the component.
The method of claim 4, comprising: pressing the engagement tool against the component to generate a bending stress in the first and/or second arm so as to flex the first arm relative to the second arm.
6 The method of claim 4 or 5, wherein the component is a first component, the method comprising: clamping a second component to the first component with a clamp, wherein the jig is attached to the clamp.
7 The method of any one of claims 4 to 6, comprising: locating the jig at a drilling position on the first component; drilling the hole in the first component through the jig; inserting the fastener into the hole of the first component, wherein the jig is maintained in the drilling position whilst drilling the hole and inserting the fastener.
8. An assembly comprising: a fastener having a fastener head; and an engagement tool for engaging the fastener head, the engagement tool comprising a first arm having a first engagement means and a second arm having a second engagement means, the first and second engagement means arranged to engage the fastener head so that the fastener head is removably fixed between the first and second arms in a first configuration, wherein the first arm is configured to flex relative to the second arm so as to disengage the first and second engagement means from the fastener head in a second configuration 9 The assembly of claim 8, wherein the first engagement means is a first recess for engaging a first portion of the fastener head; and the second engagement means is a second recess for engaging a second portion of the fastener head opposite the first portion.The assembly of claim 8 or 9, comprising a third arm positioned between, and parallel to, the first and second arms, wherein an end portion of the third arm is configured to engage an end face of the fastener head.11 The assembly of any one of claims 8 to 10, wherein an end portion of the first and second arms is tapered such that a distance between the first and second end portions of the respective first and second arms increases towards a tip end of the first and second arms.12. The assembly of any one of claims 8 to 11, wherein the engagement tool comprises plastic.13. The assembly of any one of claims 8 to 12, wherein the first arm and the second arm are formed of a material having a bending modulus of less than 10 GPa, and preferably less than 5 GPa.14. The assembly of any one of claims 8 to 13, wherein the first arm and the second arm are formed of a material having a bending modulus of more than 0.1 GPa, and preferably more than 0.5 GPa.15. The assembly of any one of claims 8 to 14, comprising: a component having a hole for inserting the fastener; a jig abutting the component, the jig having a through-hole extending through to the hole of the component, wherein the engagement tool is configured to extend through the through-hole of the jig and insert the fastener into the through-hole of the component.16 The assembly of claim 15, wherein the engagement tool is arranged such that pressing the first and second arms against the component is configured to generate a bending stress in the first and second arms so as to flex the first arm relative to the second arm.17. The assembly of claim 15 or 16, wherein the component is a first component and the hole is a through-hole, and further comprising: a second component abutting the first component, and a clamp having a first jaw and a second jaw clamping the first and second components together, and wherein the jig is attached to the clamp, and the through-hole of the jig is aligned with the through-hole of the first component.18 The assembly of claim 17, wherein a robot end effector is coupled to the clamp 19 The assembly of any one of claims 8 to 18, wherein the assembly is an aircraft assembly, the first component is a rib web of an aircraft wing, and the second component is a rib foot of an aircraft wing or a rib post of an aircraft wing.An aircraft comprising the assembly of any one of claims 8 to 19.