GB2577326A

GB2577326A - Harness guide members

Info

Publication number: GB2577326A
Application number: GB1815514.3A
Authority: GB
Inventors: Blythe David; Lewis Kiaran
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2018-09-24
Filing date: 2018-09-24
Publication date: 2020-03-25
Also published as: GB201815514D0

Abstract

A harness guide member 20 comprising: a bracket 22 for attaching the guide to a mounting structure 11; a guiding portion 21 formed integrally with the bracket, the guiding portion has a curved guiding surface 211; and where the guide has a predefined build axis B1, and is configured to be self-supporting when B1 is vertical. Preferably the bracket has teardrop shaped non-circular fastener holes (521, figure 5c) for fastening the guide to an aircraft structure. The guide may comprise cable ties (37, figure 3) to constrain the bent harness through aperture 13. A method of manufacturing a harness guide member using an additive manufacturing process comprising: (a) providing a first layer of a fusable build material on a build surface; (b) selectively fusing the material in regions of the first layer that will form part of the completed harness guide member; (c) providing a second layer of fusable material on the first layer; and (d) selectively fusing the material in regions of the second layer that will form part of the guide; (e) repeating (c)-(d) until the fused build material forms the guide; and removing unfused material from around the guide; the fused build material is self-supporting during the method.

Description

HARNESS GUIDE MEMBERS

TECHNICAL FIELD

[0001] The present invention relates to a harness guide member, to an aircraft structure having a harness guide member attached thereto, and to a method for manufacturing a harness guide member.

BACKGROUND

[0002] In aircraft, clearances must he maintained between cable harnesses and any adjacent structures (including other cable harnesses or systems components). Such clearances arc necessary to avoid chafing of the harnesses against the adjacent structures due to vibrations experienced during operation of the aircraft. It is also necessary to ensure that any bends in a cable harness have a sufficiently large radius, which depends on the nature of the cables in the harness.

[0003] The route and possible in-operation movements of a cable harness in an aircraft arc conventionally constrained by using P-clips mounted on angle brackets to attach the harness to structural components of the aircraft at multiple locations along the harness. However; there are various limitations associated with the use of P-clips for this purpose. For example, where the route of the harness must be tightly constrained, it. may be necessary to use a relatively large number of P-clips in a small space. However; it may he difficult to find suitable mounting points in all of the locations where a P-clip would ideally be used. Furthermore, because it is often not possible to constrain a harness particularly tightly, the clearance between the harness and adjacent structures may need to be larger, to avoid any possibility of chafing, than would be necessary if tighter control of harness position and movement were possible. In many locations in an aircraft, such as within the wings, it is difficult to achieve the required clearances within the available space.

[0004] An improved way of constraining the position and movement of a cable harness is therefore desired.

SUMMARY

[0005] A first aspect of the present invention provides a harness guide member comprising a bracket for attaching the guide member to a mounting structure; and a guiding portion formed integrally with the bracket. The guiding portion has a curved guiding surface. The guide member has a predefined build axis, and is configured to be self-supporting when the build axis is vertical.

[0006] Optionally, the curved guiding surface is configured to be in close contact with a cable harness guided by the guide member.

[0007] Optionally, the harness guide member further comprises retaining features for enabling a cable harness to be retained in close contact with the guiding surface. Optionally the retaining features are formed integrally with the curved portion and/or the bracket.

[0008] Optionally, the build axis is substantially aligned with a longest dimension of the harness guide member.

[0009] Optionally, the curved guiding surface has a predefined radius of curvature.

Optionally, the radius of curvature is selected based on a parameter of a cable harness intended to be guided by the harness guide member.

[0010] Optionally, the guide member is monolithic.

[0011] Optionally, the bracket comprises at least one non-circular fastener hole.

[0012] Optionally, the or each non-circular fastener hole has a teardrop shape and the long axis of the teardrop is aligned with the build axis.

[0013] Optionally, the guide member is configured to extend through an aperture in a structure. Optionally, the guide member is configured such that the guiding part is disposed within the aperture when the guide member is attached to the mounting structure.

[0014] Optionally, the guide member is formed from a fusable material. Optionally, the guide member comprises layers of the fusable material fused together by an additive manufacturing process.

[0015] A second aspect of the present invention provides a structure having an aperture extending through a first part of the structure and a harness guide member according to the first aspect fixedly attached to a second part of the structure. The guiding part of the guide member is disposed within the aperture.

[0016] Optionally, the structure further comprises a cable harness attached to the guide member such that the cable harness is retained in close contact with the curved guiding surface.

[0017] Optionally, the cable harness is retained in close contact with the curved guiding surface by one or more retaining members engaged with retaining features on the harness guide member.

[0018] Optionally, any given location on the cable harness is spaced apart from any given location on the aperture by at least a predefined minimum distance.

[0019] Optionally, the curvature of a part of the cable harness that is in contact with the curved guiding surface matches the curvature of the curved guiding surface.

[0020] Optionally, the first part of the structure is integral with the second part of the structure.

[0021] Optionally, the first part of the structure is comprised in a different component to the second part of the structure.

[0022] Optionally, the structure is an aircraft structure.

[0023] A third aspect of the present invention provides an aircraft comprising the structure of the second aspect.

[0024] A fourth aspect of the present invention provides a method for manufacturing a harness guide member using an additive manufacturing process. The method comprises: forming a harness guide member by: providing a first layer of a fusable build material on a build surface; selectively fusing the build material in one or more regions of the first layer that will form part of the completed harness guide member; providing a second layer of the fusable build material on the first layer; and selectively fusing the build material in one or more regions of the second layer that will form part of the completed harness guide member; repeating (c) and (d) until the fused build material forms the completed harness guide member; and removing unfused build material from around the completed harness guide member.

The fused build material is self-supporting during the entire performance of the method.

[0025] Optionally, only regions of the first layer and the second layer that will form part of a completed harness guide member are fused.

[0026] Optionally, the harness guide member is a harness guide member according to the first aspect and the build surface is perpendicular to the predefined build axis.

[0027] A fifth aspect of the present invention provides a computer program element which, when executed on a computer-controlled device for carrying out an additive manufacturing process, implements the method of the fourth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [0029] Figure 1 is a schematic side view of an example cable harness passing through an aperture in a structure; [0030] Figures 2a and 2b are schematic views of the example cable harness of Figure 1 being guided by a first example harness guide member according to the invention; [0031] Figures 3 is a schematic side view of the example cable harness of Figure 1 being guided by a second example harness guide member according to the invention; [0032] Figure 4 shows the first example harness guide member of Figure 2 and the second example harness guide member of Figure 3 on a build surface of an additive manufacturing apparatus; [0033] Figure 5a is a perspective view of an example harness guide member according to the invention; [0034] Figure 5b is a side view of the example harness guide member of Figure 5a; [0035] Figure 5c is a front view of the example harness guide member of Figure 5a; [0036] Figure 6 is a flow chart illustrating an example method of manufacturing a harness guide member according to the invention; and [0037] Figure 7 is an example aircraft comprising a harness guide member according to the invention.

DETAILED DESCRIPTION

[0038] The examples described below relate to harness guide members, for constraining the routes taken by cable harnesses. Each harness guide member according to the invention comprises a bracket for attaching the guide member to a mounting structure; and a guiding portion formed integrally with the bracket. The guiding portion has a curved guiding surface. Each harness guide member has a predefined build axis, and is configured to be self-supporting when the build axis is vertical or substantially vertical.

[0039] For the purposes of this specification, -vertical" means aligned with the direction of the force of gravity, and "self-supporting" means that an object is able to maintain its configuration, position and orientation without being supported by something else.

[0040] As discussed above, it is often necessary to constrain the route taken by a cable harness to ensure that sufficient clearance is maintained between the cable harness and adjacent structures to avoid the possibility of chafing, and/or to ensure that any bends in the cable harness have a sufficiently large radius to avoid the cables in the harness experiencing excessive mechanical strain. Maintaining sufficient clearances is particularly important where the harness passes through an aperture in a structure, since the edges of the aperture may be relatively sharp.

[0041] Figure 1 shows a cable harness 12 passing through an aperture 13 in a structure 11. In the particular example the structure 11 is substantially planar, at least in the region immediately surrounding the aperture. The structure 11 may be an aircraft structure. In some examples the structure 11 is a cover panel of an aircraft wing. The aperture 13 may have any shape and may be formed by any suitable process. The cable harness 12 may he any type of cable harness. In some examples the cable harness 12 comprises at least one high-voltage DC (HVDC) cable.

[0042] The cable harness 12 bends through 90° as it passes through the aperture 13. The radius R of the bend must not be less than a predefined minimum value Rmin, which may, for example, be determined based on properties of the cable harness 12. Such properties may include, for example, the number of cables in the cable harness, the stiffness of the cables in the cable harness, the diameter of the cables in the cable harness, or the like. The distance d between the cable harness 12 and the adjacent structure must not be less than a predetermined minimum value dmi", which may, for example, be determined based on the amount of movement the cable harness is expected to experience during operation (for example, due to vibrations of a vehicle in which the cable harness is installed). In the aerospace field, there exist industry standards for the values of Rmin and [0043] Using conventional harness retention techniques it. is not possible to constrain the position of a bent. portion of a cable harness tightly enough to guarantee that the values of R and d will remain above and Dmi" respectively if the bent portion is within an aperture (unless that aperture is unusually large relative to the size of the cable harness). This is because a conventional P-clip can only restrain a single axial location on a cable harness, and the harness regions between adjacent P-clips are left unrestrained. The number of P-clips that. would be needed to constrain a bent portion of a cable harness tightly enough to allow that bent portion to be disposed within an aperture is impractically large, and would be impossible to implement in many situations. On the other hand, increasing the size of the aperture is typically undesirable because of the weakening effect that an aperture has on the structure through which that aperture extends.

[0044] The example harness guides according to the invention are able to tightly constrain the route (that is, the position and curvature) of a bent portion of a cable harness. In particular, the example harness guides according to the invention are able to constrain the route of a bent portion of a cable harness tightly enough that the bent portion can be disposed within an aperture in a structure, even when that aperture is relatively small. In some examples the aperture may be as small as possible whilst still respecting //min.

[0045] Figures 2a and 2b show the structure 11, aperture 13, and cable harness 12 of Figure 1, together with an example harness guide member 20 provided to constrain the position and curvature of the bent portion of the cable harness 12. The harness guide member 20 comprises a bracket 22 and a guiding portion 21.

[0046] The bracket 22 is configured for attaching the guide member 20 to a mounting structure. For example, the bracket 22 may have a surface configured to match a corresponding surface on the mounting structure, and may include one or more features to facilitate attachment of the bracket to the mounting structure, such as fastener holes. In the illustrated example, the bracket 22 is configured to attach the guide member to the structure 11 in which the aperture 13 is present, and so the bracket 22 has a substantially flat surface configured to abut a substantially flat lower (with respect to the orientation shown in Figure 2a) surface of the structure 11. The bracket 22 is fixedly attached to the structure 11 by any suitable mechanism known in the art, such as fasteners or a bonding agent. The shape of the bracket 22 may be designed such that it contains as little material as possible whilst meeting desired performance criteria.

[0047] The guiding portion 21 is formed integrally with the bracket 22. The guiding portion 21 has a curved guiding surface 211. The guiding surface 211 is in close contact with the cable harness 12. The close contact between the guiding surface 211 and the cable harness 12 may be maintained by any suitable retaining mechanism, such as cable tics which encircle the guiding portion 21 and the cable harness 12. The curvature of the guiding surface 211 is selected to match a desired curvature of the bent portion of the cable harness 12. The radius of curvature may he selected based on a parameter of a cable harness intended to he guided by the harness guide member 20. In the illustrated example the guiding surface 211 has a constant radius of curvature, although this need not be the case in all examples. The radius of curvature of the guiding surface 211 is greater than or equal to R"d". In the illustrated example the guiding surface 211 is also curved in the plane which extends out of the page, as shown by Figure 2b. Figure 2b is a cross-section through the guiding part 21 and cable harness 12 along the line A-A. The curvature in the radial plane relative to the cable harness enables the guiding part to substantially prevent lateral movement (that is, movement along the direction labelled X in Figure 2h) of the cable harness 12.

[0048] The guiding portion 21 is joined to the bracket 22 by a bridging portion 23. The bridging portion 23 is formed integrally with the guiding portion 21 and with the bracket 22, such that the complete harness guide member 20 is a monolithic structure. The bridging portion 23 is configured to maintain a predefined relative position and orientation of the guiding surface 211 and the bracket 22. The predefined relative position and orientation may be defined, for example, such that the distances d arc greater than or equal to dm', at all points on the cable harness when the guide member 20 is attached to the structure 11 and the cable harness 12 is installed on the guide member 20. The bridging portion 23 may be configured to contain as little material as possible whilst having enough strength and rigidity to maintain the predefined relative position and orientation of the guiding surface 211 and bracket 22 during operation. In some examples the bracket 22 may be directly joined to the guiding portion 21, in which case the harness guide member 20 will not comprise a bridging portion 23.

[0049] It is desirable for the shape of a harness guide member according to the invention to he tailored to a particular location where it is to he used, and/or a particular type of cable harness that is to be guided. Particularly for aerospace applications, it is desirable for a harness guide member to be as small and light as possible whilst achieving a desired guiding/restraining effect. Conventionally, bespoke parts are manufactured from aluminium alloys or titanium alloys using manufacturing methods such as milling, turning or casting. However, these manufacturing techniques places design constraints on the configuration of the parts. For example, freeform areas, undercut areas or cavities can be produced only to a limited extent. This may result in parts that contain more material than would otherwise be necessary. The resulting higher weight is undesirable, in particular for aerospace applications, because it results in higher energy consumption during the flight phase.

MOW Some harness guide members according to the invention can he manufactured using conventional techniques such as milling, turning, or casting. However; it may generally be more advantageous to create an example harness guide member according to the invention, such as the harness guide member 20, using an additive manufacturing (AM) process. Using an AM process can enable the harness guide member 20 to have an optimised configuration such that it is as light as possible whilst having sufficient strength and rigidity to achieve the desired constraining effect on the cable harness 12.

[0051] Certain features of the design of the harness guide member 20 may be selected to facilitate creation of the harness guide member 20 using an AM process. As mentioned above, the harness guide member 20 has a predefined build axis Bi. The term "build axis" is intended to mean an axis of a component being created by an AM process that is vertical during the creation of the component. The build axis is typically perpendicular to a build surface or substrate used in the AM process. It will he appreciated that the build axis need not be vertical in an intended in-use orientation of the component. The example harness guide member 20 is configured to he self-supporting when the build axis B1 is vertical. This is advantageous for AM because it means that no support members are required to be manufactured alongside the harness guide member, and post-processing of the harness guide member can he reduced or eliminated.

[0052] The particular example harness guide member 20 comprises various features which enable it to be self-supporting. In particular, it has a base 24, which comprises a flat surface perpendicular to the build axis Bt. In the illustrated example, the base 24 is created by extending the side walls of the guiding portion 21, such that each side wall has a roughly triangular protrusion. The distribution of mass within the harness guide member 20 may also be tailored to make it self-supporting. For example, with the particular harness guide member configuration shown in Figures 2a and 2b, the bracket 22 may be relatively heavier than it would otherwise need to be so that the centre of mass of the harness guide member 20 is over the flat surface 24 when the build axis Bi is vertical.

[0053] In the particular example of Figures 2a and 2h, the build axis Bi is also substantially aligned with a longest dimension of the harness guide member 20, which advantageously facilitates simultaneous manufacturing of multiple harness guide members 20 by a single AM machine.

[0054] Figure 3 shows show the structure 11, aperture 13, and cable harness 12 of Figure 1, together with a second example harness guide member 30 provided to constrain the position and curvature of the bent portion of the cable harness 12. The harness guide member 30 comprises a bracket 32 and a guiding portion 31. The guiding portion 31 comprises a guiding surface 311, and has substantially the same features as the guiding portion 21 or the example harness guide member 20. The bracket 32 has substantially the same features as the bracket 12 of the example harness guide member 20. However, the bracket 32 is directly connected to (and in the particular example is integral with) the guiding part 31, such that the harness guide member 20 does not comprise a bridging portion. The bracket 32 is not configured to attach to the structure 11 in which the aperture 13 is present. Instead, the bracket 32 is configured to attach to a mounting structure 35. A substantially flat lower (with respect to the orientation shown in Figure 3) surface of the bracket 32 is configured to abut a substantially flat upper surface of the mounting structure 35.

[0055] In contrast to the harness guide member 20, the harness guide member 30 is configured to contact the outside (with respect to the radius of curvature) surface of the curved portion of the cable harness 12. Whether a given harness guide member according to the invention contacts the inner or outer surface of a curved portion of a cable harness will typically depend on the configuration of the space in which the harness guide member is to be installed, and the position of suitable mounting structures.

[0056] The harness guide member 30 comprises a base 34, which comprises a flat surface perpendicular to a build axis B2 of the harness guide member 30. The base 34 is created by one or more protrusions which extend from the outer surface of the guiding portion 31. Like the harness guide member 20, the harness guide member 30 is self-supporting when the build axis B2 is vertical, and the distribution of mass within the harness guide member 30 may be tailored to enable it to be self-supporting.

[0057] In the particular example, the one or more protrusions each have an opening 36 extending therethrough. The or each opening 36 is configured to engage with a retaining feature such as a cable tic 37, to facilitate retaining the cable harness 12 in close contact with the guiding surface 311. Although only one such opening 36 and cable tie 37 arc shown in Figure 3, typically multiple cable ties 37 may be used. There may not be an opening 36 corresponding to each cable tie 37 that is used to retain the cable harness 12 in close contact with the guiding surface 311.

[0058] As discussed above, it may be advantageous to manufacture harness guide members according to the invention using an additive manufacturing process. Figure 4 shows the example harness guide members 20 and 30 resting on a build surface 40 of an AM machine, as would be the case towards the end of an AM manufacturing process. Figure 4 is intended to illustrate how the example harness guide members 20, 30 are self-supporting when their respective build axes B1, B7 are vertical and how having a build axis which is substantially aligned with the longest dimension of a harness guide member can facilitate simultaneously manufacturing multiple of those harness guide members using a single AM machine. It will be appreciated that in a real-life scenario, harness guide members being simultaneously manufactured by the same AM machine may more usually have the same design.

[0059] Figures 5a-c show a particular example harness guide member 50, the design of which has been optimised for manufacture by an AM process. The harness guide member 50 may have any or all of the features of the example harness guide members 20, 30 described above. The harness guide member 50 is configured to constrain the position and curvature of bent portions of two cable harnesses. As such, it comprises a first guiding portion 51a having a first guiding surface 511 a, and a second guiding portion 5 lb having a second guiding surface 511b. Each guiding portion 51a, 51b has substantially the same features as the guiding portions 21 and 31 of the example harness guide members 20 and 30. Each guiding portion 51a, 51b has curvature in two orthogonal planes. The guiding portions 51a, 51b are mirror images of each other.

[0060] The harness guide member 50 comprises a base 54. The base 54 is formed by protrusions 55 which extend from an outer surface of each guiding portion 51a, 51b, and which have a flat surface perpendicular to a build axis Bs. The base 54 is additionally formed by a first. connecting portion 58, which extends between and is formed integrally with the protrusions 55. The first connecting portion 58 is substantially planar and has a lower surface that is coplanar with the flat surfaces of the protrusions 55. The first connecting portion 58 is configured such that it contains as little material as possible whilst. having sufficient. strength and rigidity to maintain a predefined relative position and orientation of the guiding portions 51a, 51b during operation of the harness guide member 50. The first connecting portion 58 is further configured such that it is self-supporting when the build axis BS is vertical, to enable the first connecting portion 58 to be formed as part of an AM process.

[0061] Each of the protrusions 55 comprises openings 56. The form and function of the openings 56 may be substantially the same as the opening 36 described above.

[0062] The harness guide member 50 comprises two brackets 52a, 52b. The first bracket 52a is directly connected to the first guiding portion 51a and the second bracket 52b is directly connected to the second guiding portion 51b. Each of the first and second brackets 52a, 52b has substantially the same features as the brackets 22 and 32 described above. In the particular example, each of the first and second brackets 52a, 52b comprises fastener holes 521 to facilitate attachment of the first and second brackets 52a, 52b to a mounting structure. The fastener holes 521 are non-circular. In particular, each fastener hole 521 has a teardrop shape and the long axis of the teardrop is aligned with the build axis B3. The teardrop shape is self-supporting, so it enables the fastener holes 521 to be formed as part of an AM process rather than needing to be drilled out in a post-processing step.

[0063] The brackets 52a, 52b are connected by a second connecting portion 59. The second connecting portion 59 extends between and is integral with the brackets 52a, 52b. The second connecting portion 59 is configured such that it contains as little material as possible whilst having sufficient strength and rigidity to maintain a predefined relative position and orientation of the brackets 52a, 52b during operation of the harness guide member 50. The second connecting portion 59 is further configured such that it is self-supporting when the build axis B3 is vertical, to enable the second connecting portion 59 to he formed as part of an AM process.

[0064] The entire harness guide member 50 is monolithic and is formed from a fusable material that has been fused during an AM process. The fusable material may be, for example, a metal or plastic material which is in a powdered or granular form prior to being fused. Preferably all features of the harness guide member 50 are formable during the AM process, such that the amount of post-processing required to finish the manufacture of the harness guide member 50 is minimal, or none.

[0065] Figure 6 is a flow chart illustrating an example method 600 of manufacturing a harness guide member according to the invention (e.g. any of the example harness guide members 20, 30, 50 discussed above) using an additive manufacturing process.

[0066] In a first block 601, the harness guide member is formed by an additive manufacturing technique. Forming the harness guide member comprises: (a) providing a first layer of a fusable build material on a build surface; (b) selectively fusing the build material in one or more regions of the first layer that will form part of the completed harness guide member; (c) providing a second layer of the fusable build material on the first layer; and (d) selectively fusing the build material in one or more regions of the second layer that will form part. of the completed harness guide member. Steps (c) and (d) are then repeated until the fused build material forms the completed harness guide member.

[0067] In steps (b) and (d) only regions of the first. layer and the second layer that. will form part of a completed harness guide member are fused. The regions of the first layer and the second layer arc configured and located such that the completed harness guide member is oriented as shown in Figure 4. The build surface is perpendicular to the predefined build axis. The build axis of the harness guide member is, by definition, vertical during all stages of the formation process. Since the harness guide member is sell-supporting when the build axis is vertical, there is no need to form any support members to maintain the configuration or orientation of the harness guide member during the forming of the harness guide member.

[0068] Forming the harness guide member may by an additive manufacturing technique may comprise forming one or more non-circular fastener holes. Such non-circular fastener holes may have a teardrop shape such that the long axis of the teardrop is parallel to the build axis, and is therefore vertical during the performance of block 601.

[0069] Any suitable layer-based additive manufacturing technique can be used to perform steps (a)-(d). For example, performing steps (a)-(d) of the block 601 may comprise performing a selective laser melting process. Additive manufacture based on selective laser melting involves distributing thin layers of atomized fine metal powder onto the build surface using a coating mechanism. Once a layer has been deposited, a 2D slice of the item being manufactured is fused by selectively melting the powder using a high-power laser beam. The laser energy is intense enough to fully melt the metal particles so that they fuse to form a solid metal layer. This depositing and melting process is repeated layer after layer until the item is complete.

[0070] With layer-based additive manufacturing techniques such as selective laser melting, it is not generally possible to form overhanging features which are angled by more than 30° to the vertical. If an item requires such features, they must be created during a post-processing step performed after the additive manufacturing process is complete, e.g. using conventional techniques such as drilling and/or machining. As discussed above, the example harness guide members according to the invention are preferably designed such that they do not. include any features which cannot be created by an additive manufacturing process. As such, the method 600 preferably includes minimal or no post-processing steps in which the completed harness guide member is further modified following completion of the additive manufacturing process.

[0071] In a second Mock 602, unfused build material is removed from around the completed harness guide member. Any suitable process may be used to remove the unfused build material. Since the completed harness guide member is self-supporting in the orientation in which it is formed, there is no need to support it during the performance of block 602.

[0072] The fused build material (which may comprise the completed harness guide member, or may comprise a partially formed harness guide member) is self-supporting during the entire performance of the method 600.

[0073] The method 600 may he performed simultaneously in respect of multiple harness guide members, or in respect of a harness guide member and one or more different components. A single additive manufacturing device may be used to simultaneously perform the method 600 in respect of multiple items. The number of items which can he simultaneously manufactured by a single additive manufacturing device, using the method 600, is limited by the footprint of the items in the plane of the build surface, and the size of the build surface. As discussed above, the example harness guide members according to the invention may advantageously he configured to have a small footprint in the plane of the build surface, to facilitate simultaneous manufacture of multiple harness guide members.

[0074] The method 600 may be performed, entirely or in part, by a computer-controlled additive manufacturing device. In such examples, the method 600 (or a part thereof) may be implemented by a computer program element executed on the computer-controlled additive manufacturing device.

[0075] Example harness guide members according to the invention may be particularly suitable for use on aircraft. Figure 7 shows an example aircraft 700 comprising at least one harness guide member (not visible) according to the invention. The at least one harness guide member may be any of the example harness guide members 20, 30, 50 described above.

[0076] A wing 701 of the aircraft 700 comprises a high-voltage cable harness for supplying electrical power to moveable devices installed on the wing. The cable harness does not pass through the fuel tanks formed by the wing structure, and instead is routed outside of the main wing structure to bypass the fuel tanks. A fairing (not visible) is attached to the outside of the wing to contain and protect the cable harness. It is desirable for this fairing to he as small as possible, to minimise the negative effect on the aerodynamic performance of the wing 701.

[0077] The route of the cable harness passes through at least one aperture in the wing skin, and must also bend through approximately 90° at or near the location of the aperture. It is desirable for the bent portion of the cable harness to be disposed within the aperture, so that the harness can he as dose as possible (whilst respecting and d),"") to the outer skin of the wing 701 for the portion of its route where it is outside of the main wing structure. This configuration of the cable harness and surrounding structures may be the same as that shown in Figure 3, when the structure 11 containing the aperture is a wing skin and the mounting structure 35 is a fairing. In order to constrain the position and curvature of the bent portion of the cable harness tightly enough for it to be disposed within the aperture, a harness guide according to the invention is used in the manner described above in relation to Figures 1-3. The harness guide member may be Fixedly attached to the wing skin, the fairing, or both, or indeed any other suitably located part of the aircraft structure.

[0078] The example harness guide members may be used in various other locations on the aircraft 700. In particular, harness guide members according to the invention may be of particular benefit in any location where a cable harness must bend near an adjacent structure. The particular configuration of each given harness guide member comprised in the aircraft 700 will typically be tailored to the particular location of that harness guide member.

[00791 Although the invention has been described above with reference to one or more preferred examples or embodiments, it will he appreciated that various changes or modifications may he made without departing from the scope of the invention as defined in the appended claims.

[00801 Where the term "or" has been used in the preceding description, this term should be understood to mean "and/or", except where explicitly stated otherwise.

Claims

CLAIMS: 1. A harness guide member comprising: a bracket for attaching the guide member to a mounting structure; and a guiding portion formed integrally with the bracket, the guiding portion having a curved guiding surface; wherein the guide member has a predefined build axis, and is configured to be self-supporting when the build axis is vertical.
2. A harness guide member according to claim 1, wherein the curved guiding surface is configured to be in close contact with a cable harness guided by the guide member.
3. A harness guide member according to claim 2, further comprising retaining features for enabling a cable harness to be retained in close contact with the guiding surface, the retaining Features being formed integrally with the curved portion and/or the bracket.
4. A harness guide member according to any preceding claim, wherein the build axis is substantially aligned with a longest dimension of the harness guide member.
5. A harness guide member according to any preceding claim, wherein the curved guiding surface has a predefined radius of curvature.
6. A harness guide member according to claim 5, wherein the radius of curvature is selected based on a parameter of a cable harness intended to be guided by the harness guide member.
7. A harness guide member according to any preceding claim, wherein the guide member is monolithic.
8. A harness guide member according to any preceding claim, wherein the bracket comprises at least one non-circular fastener hole.
9. A harness guide member according to claim 7, wherein the or each non-circular fastener hole has a teardrop shape and the long axis of the teardrop is aligned with the build axis.
10. A harness guide member according to any preceding claim, wherein the guide member is configured to extend through an aperture in a structure.
11. A harness guide member according to claim 10, wherein the guide member is configured such that the guiding part is disposed within the aperture when the guide member is attached to the mounting structure.
12. A harness guide member according to any preceding claim, wherein the guide member is formed from a fusable material.
13. A harness guide member according to claim 12, wherein the guide member comprises layers of the fusable material fused together by an additive manufacturing process.
14. A structure having an aperture extending through a first part of the structure and a harness guide member according to any of claims 1 to 13 fixedly attached to a second part of the structure, wherein the guiding part of the guide member is disposed within the aperture.
15. A structure according to claim 14, further comprising a cable harness attached to the guide member such that the cable harness is retained in close contact. with the curved guiding surface.
16. A structure according to claim 15, wherein the cable harness is retained in close contact with the curved guiding surface by one or more retaining members engaged with retaining features on the harness guide member.
17. A structure according to claim 15 or claim 16, wherein any given location on the cable harness is spaced apart. from any given location on the aperture by at. least a predefined minimum di stance
18. A structure according to any of claims 15 to 17, wherein the curvature of a part of the cable harness that is in contact with the curved guiding surface matches the curvature of the curved guiding surface.
19. A structure according to any of claims 14 to 18, wherein the first part of the structure is integral with the second part of the structure.
20. A structure according to any of claims 14 to 18, wherein the first part of the structure is comprised in a different component to the second part of the structure.
21. A structure according to any of claims 14 to 20, wherein the structure is an aircraft structure.
22. An aircraft. comprising the structure of claim 20.
23. A method for manufacturing a harness guide member using an additive manufacturing process, the method comprising: forming a harness guide member by: (a) providing a first layer of a fusable build material on a build surface; (b) selectively fusing the build material in one or more regions of the first layer that will form part of the completed harness guide member; (c) providing a second layer of the fusable build material on the first layer; and (d) selectively fusing the build material in one or more regions of the second layer that will form part of the completed harness guide member; (e) repeating (c) and (d) until the fused build material forms the completed harness guide member; and removing unfused build material from around the completed harness guide member; wherein the fused build material is self-supporting during the entire performance of the method.
24. A method according to claim 23, wherein only regions of the first layer and the second layer that will form part of a completed harness guide member are fused.
25. A method according to claim 23 or claim 24, wherein the harness guide member is a harness guide member according to any of claims 1 to 13 and wherein the build surface is perpendicular to the predefined build axis.
26. A computer program clement which, when executed on a computer-controlled device for carrying out an additive manufacturing process, implements the method of any of claims 23 to 25.