GB2553795A

GB2553795A - Bondable fitting

Info

Publication number: GB2553795A
Application number: GB1615623.4A
Authority: GB
Inventors: Dobbin Richard; Gordon Michael
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2016-09-14
Filing date: 2016-09-14
Publication date: 2018-03-21
Also published as: GB201615623D0

Abstract

A bondable fitting having a body 117, comprising first surface 203a and a second surface 203b. The first surface attaches to a contact adhesive 303, which may comprise a resiliently deformable pad. The second surface may be attached to a wall by applying a bonding agent 505, such as curable adhesive or sealant, preferably by pouring through a port 311 in the body. Any excess flows out through vent 313. There may be a lip positioned between the first and second surfaces, which impedes any flow of bonding agent onto the first surface. The bondable fitting may be suitable to attach to an aircraft structural member formed of a synthetic composite material.

Description

(71) Applicant(s):

Airbus Operations Limited

Pegasus House, Aerospace Avenue, Filton, BRISTOL, BS34 7PA, United Kingdom (72) Inventor(s):

Richard Dobbin Michael Gordon (56) Documents Cited:

GB 2482737 A DE 102008058389A1

EP 1396385 A1 US 20050012002 A1 (58) Field of Search:

INT CL A47G, B64C, B64D, C09D, F16B Other: WPI, EPODOC (74) Agent and/or Address for Service:

Airbus Operations Limited

Pegasus House, Aerospace Avenue, Filton, BRISTOL, BS34 7PA, United Kingdom (54) Title of the Invention: Bondable fitting

Abstract Title: Bondable aircraft fitting with contact adhesive (57) A bondable fitting having a body 117, comprising first surface 203a and a second surface 203b. The first surface attaches to a contact adhesive 303, which may comprise a resiliently deformable pad. The second surface may be attached to a wall by applying a bonding agent 505, such as curable adhesive or sealant, preferably by pouring through a port 311 in the body. Any excess flows out through vent 313. There may be a lip positioned between the first and second surfaces, which impedes any flow of bonding agent onto the first surface. The bondable fitting may be suitable to attach to an aircraft structural member formed of a synthetic composite material.

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BONDABLE FITTING

FIELD OF TECHNOLOGY [0001] The present technology relates to bondable fittings for bonding to a substrate and to methods of bonding a bondable fitting to a substrate. The technology further relates to bondable aircraft fittings for bonding to an aircraft structural member and to methods of bonding a bondable aircraft fitting to an aircraft structural member.

BACKGROUND [0002] Fittings are commonly used in engineering as an intermediate part to fix one part of a structure to another part of the structure or substrate. A fitting may be in the form of a cable or pipe clip having one part for clipping to a pipe and another part for fixing to a structure so as to secure the pipe or cable to that structure. Many mechanisms are known for fixing fittings to structures. For example fixings or fasteners such as bolds, screws or rivets may be used. Alternatively, fittings may be glued, bonded or otherwise adhered to a structure.

BRIEF SUMMARY OF THE TECHNOLOGY [0003] Embodiments of the present technology provide a bondable fitting for bonding to a substrate, the bondable fitting comprising: a body member having a first and second fixing surfaces configured to provide one or more attachment points for the bonded fitting; and a contact adhesive provided on the first fixing surface for forming a first attachment point, wherein the second fixing surface is configured to receive a bonding agent for forming a second attachment point.

[0004] The contact adhesive is configured to fix the bondable fitting to the relevant substrate while a bonding agent is applied between the second fixing surface and the substrate and cured to bond the bondable fitting to the substrate.

[0005] The first or second fixing surface may be substantially surrounded by the second or first fixing surface respectively. The first fixing surface may be at least partially adjacent the first fixing surface. The first and second fixing surfaces may be generally co-planar. A cavity may be defined by the second fixing surface, the cavity being arranged to receive the bonding agent. The body member may define a port arranged to provide fluid communication from an exterior surface of the body member into the cavity. The body member may define a vent arranged to provide fluid communication from the cavity to an exterior surface of the body member.

[0006] The body member may carry one or more projections arranged to provide one or more standoffs for the first fixing surface from a substrate. One or more of the projections may be provided substantially at an outer edge of the second fixing surface. The body member may comprise a lip positioned the between the first and second fixing surfaces, the lip being arranged to impede a flow of bonding agent onto the first fixing surface. The first and second fixing surfaces may have substantially parallel normal axes and the body member may be at least partially resiliently deformable and configured to enable movement of the first fixing surface generally along its normal axes relative to the second fixing surface. The contact adhesive may be fixed to the first fixing surface by a resiliently deformable pad.

[0007] The body member may comprise a stanchion or a bracket. The body member may comprise a fixing structure arranged to provide a fixing point for a further fitting. The fixing structure may be provided at least in part by a port arranged to provide fluid communication from an exterior surface of the body member into the cavity. The bonding agent may comprise a curable adhesive or sealant. The cavity may comprise a first region and a second region, the first region being adjacent the body and axially thickened with respect to the second region.

[0008] Another embodiment provides a kit of parts for a bondable fitting for bonding to a substrate, the kit comprising: one or more bondable fittings comprising a body member having a first and second fixing surfaces configured to provide one or more attachment points for the bonded fitting, the second fixing surface is configured to receive a bonding agent for forming a second attachment point; and one or more portions of contact adhesive for configured for attachment to the first fixing surface for forming a first attachment point with a substrate.

[0009] The kit may comprise one or more portions of bonding agent or sealant for bonding the bondable fitting to a substrate. The bonding agent may be provided in one or more applicators.

[0010] A further embodiment provides a method of bonding a bondable fitting to a substrate, the method comprising the steps of: applying a contact adhesive provided on a first fixing surface of the bondable fitting to a substrate to fix the bondable fitting to the substrate via a first attachment point; and applying a bonding agent to a second fixing surface of the bondable fitting and to the substrate to enable the bonding of the bondable fitting to the substrate via a second attachment point when the bonding agent is in its cured state.

[0011] The method may comprise the further step of: curing the bonding agent so as to bond the bondable fitting to the substrate via the second attachment point. The bonding agent may be applied via a port in the bondable fitting arranged to provide fluid communication from an exterior surface of the bondable fitting to the second fixing surface. The bonding agent may comprise a curable adhesive or sealant. The bondable fitting may be fixed via the contact adhesive to the substrate prior to the bonding agent being applied to the second fixing surface.

[0012] A further embodiment provides a bondable fitting for bonding to a substrate substantially as disclosed herein with respect to the figures.

[0013] Another embodiment provides a method of bonding a bondable fitting to a substrate substantially as disclosed herein with respect to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] Embodiments of the technology will now be described, by way of example only, with reference to the following drawings in which:

Figure 1 is a plan view of an aircraft partially formed from a synthetic composite material in the form of carbon fibre reinforced plastic (CFRP) and comprising bondable fittings fixing aircraft system elements to aircraft structural members;

Figure 2 is a is a partial perspective view of two of the bondable fittings of figure 1 fixing an aircraft system element, in the form of a cable, to an aircraft structural member, in the form of a CFRP floor panel, in accordance with an embodiment of the present technology;

Figure 3 is a cross-sectional view of one of the bondable fittings of figure 2 in a noninstalled state;

Figure 4 is a plan view of the bondable fitting of figure 2;

Figures 5a, 5b, 5c are a sequence of cross-sectional views illustrating a method of bonding the bondable fitting of figure 2 to a structural element in accordance with a further embodiment of the present technology;

Figures 6a & 6b arc respective cross-sectional and plan views of a bondablc fitting in a noninstalled state in accordance with another embodiment of the present technology; and

Figure 7 is a cross-sectional view of a bondable fitting in a non-installed state in accordance with a further embodiment of the present technology.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE TECHNOLOGY [0015] With reference to figure 1, an aircraft 101 comprises a pair of wings 103 faired into a fuselage 105. The wings 103 each carry an engine 107. The aircraft 101 further comprises horizontal stabilizers 109 and a vertical tail plane 111 each attached at the rear of the fuselage 105. The aircraft 101 comprises structural elements that are formed from a carbon fibre reinforced plastic material (CFRP). For example, the fuselage 105 comprises structural members 113, such as cabin floor beams, formed at least in part from CFRP. The aircraft 101 further comprises distributed aircraft systems (not shown) interconnected by pipes or cables 115. A set of bondable fittings 117 are used to secure or fix the pipes or cables 115 to a suitable substrate such as one of the structural members 113. The bondable fittings 117 are configured to capture the pipes and cables 115 and are bonded to the relevant structural members 113 so as to provide physical support for the pipes or cables 115.

[0016] With reference to figure 2, each bondable fitting 117 comprises a generally cylindrical body member 201 configured at a first end to define a fixing surface 203 bonded to the structural member 113. A second end of the bondable fitting 117 carries a further fitting in the form of a cable or pipe clip 205 fixed to the pipe or cable 115 so as to capture and physically support the pipe or cable 115 with respect to the structural member 113. In the present embodiment, the bondable fitting 117 further comprises a fixing point 207 at the other end of the generally cylindrical body member 201, the fixing point 207 being configured to enable the cable or pipe clip 205 to be fixed to the bondable fitting 117 by a fixing such as a bolt or screw (not shown). In the present embodiment, the bondable fitting 117 is formed from a synthetic plastic material.

[0017] With reference to figure 3, the fixing surface 203 comprises a first fixing surface 203a and a second fixing surface 203b. In the present embodiment, the first fixing surface 203a is generally circular and formed by the first end of the cylindrical body member 201. A cylindrical resiliently deformable pad 301 that generally conforms to the first fixing surface 203a is bonded to the first fixing surface 203a. The exposed surface of the pad 301 generally parallel to the fixing surface 203a carries a layer of contact adhesive 303. The body member 201 further comprises a flange 305 extending radially from the first end of the body member 201in a generally perpendicular direction with respect to the axis y of the body member 201. The flange 305 is configured to be resiliently deformable with respect to the body member 201.

[0018] The surface of the flange 305 generally co-planar with the first fixing surface 203a, defines the second fixing surface 203b. A continuous lip 307 is formed by the radially outer edge of the flange 305. The lip 307 is in the form of a standoff for the first and second fixing surfaces 203a, 203b with respect to the notional surface 5' of the relevant substrate such as the structural member 113. In the present embodiment, since the planes of the first and second fixing surfaces 203a, 203b are spaced along the axis y, the first fixing surface 203a is provided with a first standoff distance s_a and the second fixing surface 203b is provided with a second standoff distance Sb- In the present embodiment, the difference between the first and second standoff distances s_a, Sb is determined by the thickness of the pad 301 and contact adhesive 303.

[0019] The lip 307 and the second fixing surface 203b define a cavity 309 with respect to the surface S. The flange 305 defines a plurality of through-holes defining a first port 311 and a second port 313 arranged respectively to provide fluid communication though the flange 305 into and out of the cavity 309. In other words, as shown in figure 4, the first port 311 is arranged to provide an inlet for fluid, such as a bonding agent (not shown), into the cavity 309 and the second port 313 provides a vent to enable air within the cavity 309 to be displaced from the cavity 309 by the introduced bonding agent. In the present embodiment, the second fixing surface 203b is generally ring shaped and extends from the distal edge of the lip 307 to adjacent the outer edge of the first fixing surface 203a so as to surround the first fixing surface 203a. The first fixing surface 203a is generally circular and the pad 301 and contact adhesive 303 are correspondingly dimensioned.

[0020] A method for bonding the bondable fixing 117 of figure 3 to a suitable substrate such as the structural member 113 will now be described with reference to figures 5a, 5b & 5c. With reference to figure 5a, the bondable fitting 117 is placed on the substrate 117 with the fixing surfaces 203a, 203b facing the surface of the substrate 117. The body member 201 is then pushed along its axis y towards the substrate 117. This results in the lip 307 being urged against the surface of the substrate 117 so as to deform the flange 305, enabling the contact adhesive 303 to adhere to the substrate 117 as shown in figure 5a. The resilient deformation of the pad 301 is arranged to promote increased contact between the surface of the substrate 117 and the contact adhesive 303 and to improve the resistance of the contact adhesive 303 to peeling. After this first step, the bondable fitting 117 is fixed to the substrate 117 via the first fixing surface 203a with the lip 307 resiliently biased into contact with the surface of the substrate 117.

[0021] With reference to figure 5b, an applicator 501is attached via a nozzle 503 to the inlet port 311. The applicator 501 contains a curable bonding agent 505 in the form of a curable adhesive or sealant which is injected through the port 311 into the cavity 309. Air is ejected from the cavity 309 via the vent port 313 in response to the injection of the curable bonding agent 505. Once a sufficient volume of curable bonding agent 503 has being introduced to the cavity 309, the applicator 501 is removed as shown in figure 5c. The curable bonding agent 505 substantially fills the cavity 309 and may form beads 507 around the exterior of the lip 307 and ports 311,313. The curable bonding agent 505 is then either passively or actively cured in dependence on the type of curable bonding agent resulting in the bondable fitting 117 being bonded to the substrate 113. As will be understood by those skilled in the art, the resilience of the flange 305 is configured to be within the peeling limit of the contact adhesive 303 within the expected curing period of the curable bonding agent 505. When the bondable fitting 117 is bonded to the substrate 113, a further fitting such as a pipe or cable clip 205 may be fixed to the bondable fitting 117 via the fixing point 207.

[0022] Further embodiments of the present technology will now be described with reference to figures 6a, 6b and 7. In these figures and the accompanying description, the same reference numerals are used to refer to elements which are the same or not substantially different to those of the preceding embodiments described with reference to the preceding figures.

[0023] With reference to figure 6a, in another embodiment, the region of the flange 305 adjacent the body member 201 is stepped away from the surface 5 in the axial direction y. The step in the flange 305 results in the cavity having two generally radially spaced annular regions 603a, 603b. The first region 603a is adjacent the body member 201 and extends radially up to the step in the flange 305. The second region 603b extends radial from the step in the flange 305 to the lip 307. The first region 603a is thicker in the direction y than the second region 603b. Thus, when the bondable fitting 601 has been bonded to a substrate, the first region 603a is filled with a relatively thick volume of cured bonding agent which provides additional strength or stiffness to the base of the body member 201 in its attachment region.

[0024] With reference to figure 6b, the thicker first region is 603a also configured to aid the flow of the relevant bonding agent during installation of the bondable fitting. In the present embodiment, the lip 307 is configured to define a plurality of vents 605, 607. The vents 605, 607 are of different sizes with the first vent 605 closest to the port 311 being smaller than the second vent 607 that is further from the port 311. The differential sizing of the vents 605,

607 is configured to compensate for the eccentrically located port 311 an promote even filling of the cavity 309 with bonding agent.

[0025] With reference to figure 7, in a further embodiment, the structural elements of the bondable fitting 701 that have the same function as those of the embodiment of figure 2 use the same labelling for ease of reference. In this embodiment, the first fixing surface 203a is ring-shaped and located circumferentially adjacent the outer edge of the flange 305. The contact adhesive 303 is fixed to the first fixing surface 203a via a correspondingly dimensioned ring-shaped pad 301. In this embodiment, the second fixing surface 203b is located within the first fixing surface.

[0026] In a further embodiment based on the embodiment of figure 7, an input port for injecting a bonding agent is provided by a continuation of the hole providing the fixing point 207 through the body member 201 into the cavity 309.

[0027] In another embodiment, a further lip is provided between the cavity and the first fixing surface to impede the flow of bonding agent from the cavity into contact with the contact adhesive or pad In other words, the lip is configured assist in containing the bonding agent within the cavity adjacent the second fixing surface. In a further embodiment, the standoff provided by the lip may be radially intermittent. In another embodiment, one or more vents for the cavity are provided in the lip on the outer edge of the second fixing surface. In a further embodiment, the bondable fitting comprises a plurality of vents which may be differentially sized to promote differential flow rates of the bonding agent across the cavity. In another embodiment, the ports may comprise one-way valves to enforce fluid flow in a predetermined pattern or direction.

[0028] In a further embodiment, the flange 305 and lip 307 are configured to have a substantially contiguous cross section. The flange 305 and lip 307 together provide a generally smooth concave second fixing surface 203b defining the cavity 309.

[0029] In another embodiment, the bondable fitting as described in any of the embodiments herein is provided as a kit of parts comprising one or more bondable fittings and one or more portions of contact adhesive for fixing to the first fixing surface of the bonded fitting. The contact adhesive portions may be provided separately in the form of pads carrying the contact adhesive. The kit of parts may comprise one or more portions of bonding agent. The bonding agent may be installed in an applicator.

[0030] As will be understood by those skilled in the art, the fixing surfaces may be arranged in any relative size or orientation applicable to a given application. The fixing point may be configured for use with any suitable fixing mechanism including but not limited to bonded, interference or snap-fit mechanisms. The fixing point may be omitted. The bondable fitting may provide a post, stanchion, bracket or standoff. The body member may be configured for any suitable application and sized or shaped accordingly. The body member may be integrally formed with a further fixing such as, but not limited to, a pipe or cable clip. The bondable fitting may be formed from any suitable material or combination of materials. The bondable bracket is not limited to use with CFRP but may be applied to any suitable surface made of any relevant material, for example, aluminium, steel or titanium. The contact adhesive may be applied to the first fixing surface at any suitable point prior to the installation of the bondable fitting. The contact adhesive may be applied directly to the first fixing surface or via a double sided tape, such as a very high bond tape(VHB), a sticker or a pad of any suitable thickness.

[0031] The use of the term “or” in the present document is intended to mean “and/or” and should not be interpreted as “exclusive or” unless explicitly indicated otherwise.

[0032] While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details of the representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the scope of applicant’s general inventive concept.

Claims

1. A bondable fitting for bonding to a substrate, the bondable fitting comprising:

a body member having a first and second fixing surfaces configured to provide one or more attachment points for the bonded fitting; and a contact adhesive provided on the first fixing surface for forming a first attachment point, wherein the second fixing surface is configured to receive a bonding agent for forming a second attachment point.

2. A bondable fitting according to claim 1 in which the first or second fixing surface is substantially surrounded by the second or first fixing surface respectively.

3. A bondable fitting according to any preceding claim in which the first fixing surface is at least partially adjacent the first fixing surface.

4. A bondable fitting according to any preceding claim in which the first and second fixing surfaces are generally co-planar.

5. A bondable fitting according to any preceding claim in which a cavity is defined by the second fixing surface, the cavity being arranged to receive the bonding agent.

6. A bondable fitting according to claim 5 in which the body member defines a port arranged to provide fluid communication from an exterior surface of the body member into the cavity.

7. A bondable fitting according to claim 5 or 6 in which the body member defines a vent arranged to provide fluid communication from the cavity to an exterior surface of the body member.

8. A bondable fitting according to any preceding claim in which the body member carries one or more projections arranged to provide one or more standoffs for the first fixing surface from a substrate.

9. A bondable fitting according to claim 8 in which one or more of the projections is provided substantially at an outer edge of the second fixing surface.

10. A bondable fitting according to any preceding claim in which the body member further comprises a lip positioned the between the first and second fixing surfaces, the lip being arranged to impede a flow of bonding agent onto the first fixing surface.

11. A bondable fitting according to any preceding claim in which the first and second fixing surfaces have substantially parallel normal axes and the body member is at least partially resiliently deformable and configured to enable movement of the first fixing surface generally along its normal axes relative to the second fixing surface.

12. A bondable fitting according to any preceding claim in which the contact adhesive is fixed to the first fixing surface by a resiliently deformable pad.

13. A bondable fitting according to any preceding claim in which the body member further comprises a stanchion or a bracket.

14. A bondable fitting according to any preceding claim in which the body member further comprises a fixing structure arranged to provide a fixing point for a further fitting.

15. A bondable fitting according to claim 14 in which the fixing structure is provided at least in part by a port arranged to provide fluid communication from an exterior surface of the body member into the cavity.

16. A bondable fitting according to any preceding claim in which the bonding agent comprises a curable adhesive or sealant.

17. A bondable fitting according to any of claims 5 to 16 in which the cavity comprises a first region and a second region, the first region being adjacent the body and axially thickened with respect to the second region.

18. A bondable aircraft fitting for bonding to an aircraft structural member according to any preceding claim.

19. A bondable aircraft fitting according to claim 18 in which the aircraft structural member is formed of a synthetic composite material.

20. A kit of parts for a bondable fitting for bonding to a substrate, the kit comprising:

one or more bondable fittings comprising a body member having a first and second fixing surfaces configured to provide one or more attachment points for the bonded fitting, the second fixing surface is configured to receive a bonding agent for forming a second attachment point; and one or more portions of contact adhesive for configured for attachment to the first fixing surface for forming a first attachment point with a substrate.

21. A kit of parts according to claim 20 in which the kit further comprises one or more portions of bonding agent or sealant for bonding the bondable fitting to a substrate.

22. A kit of parts according to claim 21 in which the bonding agent is provided in one or more applicators.

23. A method of bonding a bondable fitting to a substrate, the method comprising the steps of:

applying a contact adhesive provided on a first fixing surface of the bondable fitting to a substrate to fix the bondable fitting to the substrate via a first attachment point; and applying a bonding agent to a second fixing surface of the bondable fitting and to the substrate to enable the bonding of the bondable fitting to the substrate via a second attachment point when the bonding agent is in its cured state.

24. A method according to claim 23 comprising the further step of:

curing the bonding agent so as to bond the bondable fitting to the substrate via the second attachment point.

25. A method according to any of claims 23 or 24 in which the bonding agent is applied via a port in the bondable fitting arranged to provide fluid communication from an exterior surface of the bondable fitting to the second fixing surface.

26. A method according to any of claims 23 to 25 in which the bonding agent comprises a curable adhesive or sealant.

27. A method according to any of claims 23 to 26 in which the bondable fitting is fixed via the contact adhesive to the substrate prior to the bonding agent being applied to the second fixing surface.

28. A bondable fitting for bonding to a substrate substantially as disclosed herein with respect to the figures.

29. A method of bonding a bondable fitting to a substrate substantially as disclosed herein with respect to the figures.

Intellectual

Property

Office

Application No: GB 1615623.4 Examiner: Mr Michael Shaw