Abstract
A method of manufacturing a cable harness may comprise the steps of providing a plurality of cables, wherein each cable comprises a cable inner and a coating, wherein each cable inner comprises at least one conductor, locating at least a portion of each of the plurality of cables within a mould tool, heating the portions of each of the plurality of cables such that the coating of each cable consolidates to form a common harness with a solid cross section, wherein the cable inners are arranged within the common harness.
Claims
1. A method of manufacturing a cable harness for a gas turbine engine, the method comprising the steps of: providing a plurality of cables, wherein each cable comprises a cable inner and a coating, and wherein each cable inner comprises at least one conductor; locating at least a portion of each of the plurality of cables within a mould tool; heating the portions of each of the plurality of cables such that the coating of each cable consolidates to form a common harness with a solid cross section, wherein the cable inners are arranged within the common harness.
2. The method according to claim 1, wherein the step of heating the plurality of cables further comprises removing air pockets from between the plurality of cables and wherein optionally the step of heating further comprises applying a vacuum to the plurality of cables through the mould tool.
3. The method according to claim 1, wherein the step of heating the cable bundle comprises passing a current through at least one of the plurality of cables.
4. The method according to claim 1 wherein each cable is a twin core cable for a gas turbine engine.
5. The method according to claim 4, wherein each cable comprises heat treatable packer material such that each cable has a circular outer cross section.
6. The method according to claim 1, wherein the method further comprises the step of locating heat treatable filler within the mould tool.
7. The method according to claim 1, wherein the cable coatings and/or heat treatable packer material and/or heat treatable filler are formed of a thermoset or thermoplastic material.
8. The method according to claim 1, wherein an outer profile of the harness is aerofoil shaped.
9. The method according to claim 1, wherein a length of the common harness is greater than one metre.
10. The method according to claim 1, wherein the step of providing a plurality of cables comprises providing at least 10 cables.
11. The method according to claim 1, wherein the step of providing a plurality of cables comprises providing a safety critical cable, and the step of locating the plurality of cables within a mould tool comprises locating the safety critical cable towards the centre of the mould tool.
12. The method according to claim 1, wherein the step of providing a plurality of cables comprises arranging the plurality of cables into a plurality of rows and securing each row of cables together.
13. The method according to claim 1, wherein the method further comprises the step of locating clipping and/or mounting and/or connecting and/or branch portion features within the mould tool.
14. The method according to claim 1, wherein the method further comprises the step of locating a PCB within the mould tool.
15. The method according to claim 1 wherein the common harness is rigid for providing structural support to a component.
16. The method according to claim 1, wherein the cable coatings and/or heat treatable packer material and/or heat treatable filler are formed of ETFE, PTFE or a PAEK derivative.
17. The method according to claim 1, wherein the method further comprises the step of securing the harness in a composite material structure.
18. The method according to claim 1, further comprising the step of forming the cable harness into an arc, wherein optionally arc roller formers are provided that form the cable harness into an arc.
19. The method according to claim 1, wherein the mould tool comprises a loom roller, and the step of heating the portions comprises feeding the plurality of cables through the loom roller to apply heat and pressure to the plurality of cables, and optionally feeding the plurality of cables through a pre-heater before feeding the plurality of cables through the loom roller.
20. A method of assembling a gas turbine engine, the method comprising the steps of manufacturing a cable harness according to claim 1; and attaching the harness to the gas turbine engine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0091] Embodiments will now be described by way of example only, with reference to the Figures, in which:
[0092] FIG. 1 is a side view of a typical gas turbine engine;
[0093] FIG. 2 is a sectional side view of a gas turbine engine comprising a cable harness in accordance with the present disclosure;
[0094] FIGS. 3a through 3d show the cable harness at various stages of the disclosed method; FIG. 3a shows a cross section through a cable; FIG. 3b shows a cross section of a plurality of cables located within a mould tool; FIG. 3c shows a cross section through the mould tool during a step of heating; FIG. 3d shows a cross section through the resulting common harness;
[0095] FIG. 4 shows a cross section though a cable harness comprising a mounting feature;
[0096] FIG. 5 shows a top down view of a common harness with branches;
[0097] FIG. 6 shows a sectional side view of a connection between a harness and a component;
[0098] FIG. 7 shows a cross section of an alternative cable for use in a cable harness;
[0099] FIGS. 8a through 8c show an alternative connection between a harness and a component; FIG. 8a shows a plan view of the female connector; FIG. 8b shows a sectional side view of the female connector; FIG. 8c shows a sectional side view of a male and female connector connected;
[0100] FIGS. 9a and 9b show an alternative connection between a harness and a component; FIG. 9a shows a square connection; FIG. 9b shows an angled connection
[0101] FIG. 10 shows a diagrammatic view of an alternative manufacturing process using loom rollers;
[0102] FIGS. 11a and 11b show a sectional view of the loom rollers; FIG. 11a shows a sectional view of the loom rollers with a plurality of cables passing between them for consolidation into a cable harness; FIG. 11b shows a cross section of the resulting cable harness;
[0103] FIG. 12 shows a sectional view of an embodiment of the harness shaped as an aerofoil.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0104] With reference to FIG. 2, a gas turbine engine is generally indicated at 10, having a principal and rotational axis X-X. The engine 10 comprises, in axial flow series, an air intake 11, a propulsive fan 12, an intermediate pressure compressor 13, a high-pressure compressor 14, combustion equipment 15, a high-pressure turbine 16, an intermediate pressure turbine 17, a low-pressure turbine 18 and an exhaust nozzle 19. A nacelle 23 generally surrounds the engine 10 and defines both the intake 11 and the exhaust nozzle 19.
[0105] A casing 21 surrounds the front end of the gas turbine engine 10, for example the fan 12 and intermediate pressure compressor 13 as shown in the FIG. 2 example. The casing 21, which may also be known as the outer casing, supports a number of auxiliary components on its radially outer surface. A cable harness 20 is mounted to the casing 21 for transmitting power to components mounted around and off the casing 21 in the FIG. 2 example.
[0106] The gas turbine engine 10 works in the conventional manner so that air entering the intake 11 is accelerated by the fan 12 to produce two air flows: a first air flow A into the intermediate pressure compressor 13 and a second air flow B which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 13 compresses the air flow directed into it before delivering that air to the high pressure compressor 14 where further compression takes place.
[0107] The compressed air exhausted from the high-pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 16, 17, 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high 16, intermediate 17 and low 18 pressure turbines drive respectively the high pressure compressor 14, intermediate pressure compressor 13 and fan 12, each by suitable interconnecting shaft.
[0108] Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g. two) and/or an alternative number of compressors and/or turbines. Further the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.
[0109] FIGS. 3a through 3d show different stages of the method of manufacturing a cable harness from an individual cable in FIG. 3a, to a plurality of cables in a mould tool in FIG. 3b, the process of heating the mould tool in FIG. 3c to the common harness in FIG. 3d.
[0110] FIG. 3a shows a typical cable. FIG. 3a shows a typical twin core cable for a gas turbine engine. The cable has two conductors, a first wire 34 and a second wire 36. The first wire is surrounded by a coating of a first insulation 37. The second wire 36 is surrounded by a coating of a second insulation 38. Shielding 39 surrounds both the first insulation 37 and the second insulation 38. A coating 32 surrounds the shielding 39. The first wire 34, second wire 36, first insulation 37, second insulation 38 and shielding 39 form a cable inner 30.
[0111] The first wire 34 and the second wire 36 are elongate wires with a circular cross section. The first wire 34 and the second wire 36 are conductors for transmitting power to components. The first wire 34 and the second wire 36 are made of copper in the FIG. 3a example. The first wire 34 and the second wire 36 are each surrounded by a layer of insulation. With respect to the first wire 34, a layer of first insulation 37 surrounds and/or encases the first wire 34. The first insulation 37 is an even annular layer with a circular outer cross section concentric with the cross sectional centre of the first wire 34. The second wire 36 and second insulation 38 is of similar construction.
[0112] The shielding 39 surrounds and/or encases both the first insulation 37 and the second insulation 38. The shielding 39 has an elliptical outer cross sectional profile. The elliptical outer cross sectional profile allows the shielding to surround the first insulation 37 and second insulation 38 in a space and material constrained manner. The shielding 39 surrounds the insulations such that the outer surfaces of the first insulation 37 and second insulation 38 are fully in contact with the shielding 39.
[0113] The shielding 39 is surrounded and/or coated with a layer of coating 32. The layer of coating 32 encases the layer of shielding 39. The layer of coating 32 is an annular layer with an inner cross sectional profile that, in the FIG. 3a example, matches the outer cross sectional profile of the shielding 39. In the FIG. 3a example, the coating 32 has a circular outer cross sectional profile. In the FIG. 3a example, the thickness of the coating 32 varies around the circumference of the shielding 39. Alternatively the coating 32 may have a different configuration, for example as shown in FIG. 7.
[0114] FIG. 3b shows a plurality of cable inners: a first cable inner 40, second cable inner 41, third cable inner 42, fourth cable inner 43 and fifth cable inner 44. FIG. 3b shows a plurality of coatings surrounding each respective cable inner: first coating 45, second coating 46, third coating 47, fourth coating 48 and fifth coating 49. Each combination of cable inner and coating forms a cable. The plurality of cables are positioned in a mould tool 50.
[0115] In the FIG. 3b example there are five cables. The cables are arranged in two rows, a first row of three cables and a second row of two cables. The first row and second row are offset from each other so that they efficiently fill the space of the mould tool 50. The cables are arranged such that each coating abuts coatings of adjacent cables. It can be seen in FIG. 3b that because each cable is circular, each abutment shares the same geometry. For example the first coating 45 abuts the second coating 46, fourth coating 48 and fifth coating 49.
[0116] In the FIG. 3b example the mould tool 50 has two sides and a top and a bottom. The shape of the mould tool 50 matches the shape of the plurality of cables. The number of cables provided fills the mould tool 50. In the FIG. 3b example the mould tool is a polygon. In the FIG. 3b example the mould tool 50 is a trapezoid. In the FIG. 3b example the mould tool 50 has four sides.
[0117] FIG. 3c shows the arrangement of FIG. 3b during a step of heating the plurality of cables. Arrows A show the direction of heat being passed into the mould tool. In the FIG. 3b example heat and pressure are applied to the plurality of cables through the mould tool, however in other embodiments only heat is applied to the mould tool. In other embodiments the heat and/or pressure may be applied under a vacuum. When a vacuum is applied to the plurality of cables, the air pockets/voids will not contain any gas. In the FIG. 3c example, heat and/or pressure are applied uniformly around the mould tool, however in other embodiments heat and pressure may not be applied uniformly. For example in other embodiments one side of the mould tool may be translatable with respect to the other sides such that it can reduce the volume within the mould tool.
[0118] The arrows A show the direction of reduction in volume of the mould tool. FIG. 3d shows the common harness after a step of heating the plurality of cables. The common harness has a plurality of cable inners: first cable inner 40, second cable inner 41, third cable inner 42, fourth cable inner 43 and fifth cable inner 44. The cable inners are arranged within and/or embedded within and/or surrounded by the common harness 52.
[0119] The common harness 52 is formed of the coatings, for example the first coating 45, second coating 46, third coating 47, fourth coating 48 and fifth coating 49. During a step of heating the coatings consolidate into the common harness 52.
[0120] For example the coatings sinter together and fill the mould tool. For example the coatings melt together and fill the mould tool.
[0121] The outer profile of the common harness 52 may be defined by the mould tool. The outer profile of the common harness 52 may be defined by a second cross section of the mould tool. The second cross section of the mould tool is the cross section the mould tool forms at the end of the step of heating the plurality of cables. A first cross section of the mould tool may be the cross sectional shape formed in FIG. 3b. The mould tool may be configurable to move between the first cross section and the second cross section.
[0122] A method of manufacturing a cable harness will now be described with regard to FIGS. 3a to 3d. A plurality of cables of the type shown in FIG. 3a are provided. The plurality of cables are located within a mould tool according to FIG. 3b. Heat (and optionally pressure) is applied to the plurality of cables according to FIG. 3c, optionally in a vacuum. The common harness shown in FIG. 3d is produced as a result of the heating.
[0123] The arrangement of cable inners is maintained between FIG. 3b and FIG. 3d. However the cable inners may have moved closer together due to the step of heating and/or applying pressure to the plurality of cables. The cable inners are surrounded by the common harness 52 such that in a cross section, for example the cross section shown in FIG. 3d, the outer profile of each cable inner is in contact with solid material of the common harness 52. A cross section of the common harness 52, for example that shown in FIG. 3d, contains no air pockets within the common harness 52 and/or the common harness 52 is solid material. For example within an outer profile of the cross section of the common harness in FIG. 3d, there is only solid material of the common harness and the cable inners.
[0124] FIG. 3b shows air pockets between the cables before the step of heating. For example there is a space between the first coating 45, the second coating 46 and the fourth coating 48. This may be referred to as an air gap, void or pocket. Under a vacuum, an air gap, void or pocket contains no gas. In FIG. 3d, it can be seen that there is no air pocket, void or pocket between the first cable inner 40, the second cable inner 41 and the fourth cable inner 43. Therefore such an air pocket, void or pocket has been removed during the step of heating.
[0125] FIG. 4 shows a cross section through an alternative embodiment of a cable harness. FIG. 4 shows a common harness 62, a plurality of cable inners 60, two PCBs, a mounting feature 68 and a wrapper 64.
[0126] The mounting feature 68 may be a bracket or a clipping feature. The mounting feature 68 may be for attaching the cable harness to a component, for example a gas turbine engine. FIG. 4 shows an arrangement of cable inners 60 in four rows. Each row has the same number of cable inners 60 and is positioned directly above the row below. In FIG. 4, the shape formed by adjacent cable inners 60 is a square. The mounting feature 68 is positioned with a plurality of cables and is heating together with the plurality of cables to produce the cable harness shown in FIG. 4. The mounting feature 68 is integrally embedded within the cable harness, for example it extends into the common harness 62 between cable inners 60.
[0127] The cable harness has two PCB 66 wafers attached to it. The common harness 62 is of square cross section. The common harness 62 has PCBs 64 attached across two of its four sides. The cable harness comprises a wrapper 64 surrounding the common harness 62 and PCBs 66. The wrapper provides an additional layer of protection and/or additional structural strength. The mounting feature 68 extends outwardly from the common harness 62. The mounting feature 68 extends outwardly beyond the wrapper 64.
[0128] FIG. 4 shows a safety critical cable 61. A safety critical cable may transmit power to a safety critical component. For example a safety critical cable 61 may transmit power to a component that is required for a safety system. A safety critical cable 61 may transmit power to a component that is more safety critical than the components the other cables serve. The safety critical cable 61 is located towards the centre of the cable inners 60. The safety critical cable 61 is located towards the centre of the cross sectional area of the cable harness shown in FIG. 4. The safety critical cable 61 is located in a position where it is the cable closest to the centre of the cable harness cross section shown in FIG. 4.
[0129] FIG. 5 shows a top down view of a cable harness. Shown in FIG. 5 is a common harness 70, a branch portion 72 and connectors 74. The common harness 70 comprises a plurality of cable inners embedded within it (not shown in FIG. 5). The common harness splits within the branch portion 72. Whilst FIG. 5 shows the common harness splitting in a two dimensional plane, alternatively the common harness may split into different directions in a three dimensional space. The common harness 70 may be manufactured in a mould tool that is shaped to accommodate the branch portion 72. The method claimed herein may therefore be used to produce cable harnesses that branch into multiple branches. This allows for a particularly space optimised solution of arranging the cables. Each branch may comprise a connector 74 for interfacing with a component. Additionally a branch portion may comprise a pre-moulded boot. A pre-moulded boot may be made of the same material as the cable outers. The pre-moulded boot may be in the shape of the branch portion 72 before being placed in the mould tool. The pre-moulded boot may be for preventing damage during operation, for example preventing the harness unpeeling.
[0130] FIG. 6 shows the interface between the harness 80 (for example a common harness or sintered harness) and a component 83. The component comprises a PCB 82. The PCB 82 may be capable of transmitting electrical signals. A connector 86 is provided between the common harness 80 and the PCB 82. The connector comprises an interface block and pins that interface with the PCB 82. The connector 86, common harness 80 and PCB are surrounded by a wrap 84. The wrap 84 provides additional protection to the components within in the operating environments that the component experiences.
[0131] The component 83 may be a common harness. The component 83 may be a common harness as claimed herein. A signal may be transmitted in the PCB 82 along the sintered harness 83 and then transferred from the PCB 82 to the harness 80 for connection to a second component, for example via a standard electrical connector.
[0132] FIG. 7 shows an alternative cable for use in a common harness. In the FIG. 7 example there is shown the same cable inner 30 as in FIGS. 3a through 3d. However in alternative arrangements there may be a different arrangement of cable inner, for example with a different number of wires. The cable inner 30 has a first wire 34, a second wire 36, a first insulation 37 surrounding the first wire 34, a second insulation 38 surrounding the second wire 36, and a shielding 39 surrounding both the first insulation 37 and second insulation 38. The two wires in the cable inner 30 mean the resulting outer profile of the shielding 39 is elliptical in the FIG. 7 example.
[0133] Two packer material 90 are arranged adjacent the shielding 39. In the FIG. 7 example the packer material 90 are arranged adjacent the point on the elliptical outer profile of the shielding 39 of minimum radius. A layer of coating 92 then surrounds both the cable inner 30 and the two packer material 90.
[0134] The embodiment shown in FIG. 7 shows an arrangement that provides a circular cable, for example the outer cross sectional profile of the coating 92 is circular, whilst the coating 92 is of even thickness around its circumference. This is advantageous as it is easier to produce a coating 92 of even thickness, for example it may be applied as a tape wrapped around the cable inner 30 and packer material 90. The packer material 90 allows for the difference between the cross sectional inner profile of the coating 90 and the cross sectional outer profile of the shielding 39. As discussed herein, a circular cable provides for greater homogeneity of the resulting common harness, for example a common harness with fewer or no voids.
[0135] FIGS. 8a through 8c show an embodiment of a connector between a PCB 108 and a component. The component may be a cable harness as claimed herein. FIGS. 8a and 8b show the female connector 101 and FIG. 8c shows the connection between the female connector 101 and the male connector 111.
[0136] FIG. 8a shows a plan view of the female connector 101. The same female connector 101 is shown in FIG. 8b as a side cross section. FIG. 8a shows a threaded boss 102, for example a threaded polymer boss, that is a circular, annular protrusion from the PCB 108. Within the threaded boss 102 is arranged a wafer 106 with a plurality of spring loaded contacts 100. In other embodiments there may be a different number or arrangement of contacts. The PCB is arrangement against a component 110. The component 110 may be a structural component or may be a cable harness. The component 110 and PCB 108 are surrounded by a cosmetic wrapper 104. In the FIG. 8a example, the cosmetic wrapper 104 surrounds the component 110 and PCB 108 on all sides apart from at the location of the threaded boss 102, to allow a location for the signal to enter and exit the PCB 110.
[0137] FIG. 8c shows the male connector 111. The male connector 111 has an interface boss 114 on the end of the male component 112. The male component 112 may be, for example, a cable bundle or cable harness. The interface boss 114 may be internally threaded for connection to the threaded boss 112 of the female connector 101. A connector 116 extends from the interface boss 114.
[0138] In a method of connecting a cable harness, a first connector, for example attached to and/or interfacing with (for example interfacing with individual cables of) a cable harness as claimed herein, is connected to a second connector, for example attached to and/or interfacing with a component and/or second cable harness. With regard to FIGS. 9a and 9b, when the male connector 111 is screwed into the female connector 101, for example during a method of connecting a cable harness, using the respective threaded connections (or connection method if different to the FIGS. 8a through 8c examples) the connector 116 extends into the female connector 101 to contact the spring loaded contacts 100. In the FIG. 8 example, with the contacts 100 being spring loaded, a good contact is made between the connector 116 and the spring loaded contacts 100 across a depth of insertion of the connector 116 and the female connector 101, thereby allowing for tolerances. Signals may then pass between the component 110 and the male component 112.
[0139] FIGS. 9a and 9b show examples of connectors to connect the cables of a cable bundle, for example a cable harness as claimed herein, to another cable bundle, for example a cable harness as claimed herein.
[0140] FIG. 9a shows a sectional side view of a square connector. The square connector interface 126 connects a first cable bundle 120 with a second cable bundle 130. The first cable bundle 120 and second cable bundle 130 may be cable harnesses. The first cable bundle 120 is connected to the square connector interface 126. The second cable bundle 130 is connected to the cable connector 132. The cable connector 132 and square connector interface 126 interface with a bossed connection, for example an annular bossed connection, for example a threaded boss connection. An individual cable within the bundle, for example cable 124, has a connection to an individual cable in the cable bundle. Both the cable connector 132 and square connector interface 126 provide for individual connections for each cable. The square connector interface 126 turns each cable by a right angle to allow the direction of the two cable bundles to be different.
[0141] FIG. 9b shows the same arrangement as FIG. 9a, however instead of a square connector interface 126 there is an angled connector interface 128. Further there is additionally a support arm 122 that extends from the angled connector interface 128 along the cable bundle 120.
[0142] The connection apparatus and/or methods shown in the examples of FIGS. 8a, 8b, 8c, 9a, and 9b provide a space optimised, efficient connectors for a cable harness, for example for connecting individual cables of a cable harness to their respective components. For example during manufacture or maintenance, the cable harness can be quickly and easily connected to other components and/or other cable harnesses. This reduces manufacture and/or maintenance time and improves quality of the product. During the method of manufacturing a cable harness, the common harness may have a profile that is suitable for interfacing with a connection apparatus and/or method, for example further including the boot of FIG. 5.
[0143] FIG. 10 shows an alternative apparatus for manufacturing a cable harness. The apparatus in FIG. 10 is suitable for manufacturing continuous lengths (or relatively long lengths) of cable harness. The apparatus in FIG. 10 is suitable for manufacturing arced cable harnesses for fitment around the annular casing of a gas turbine engine.
[0144] FIG. 10 shows three cable looms 140 that each respectively provide a cable strand 142. The three cable strands in the FIG. 10 example join at a cable join point 144 which provides a plurality of cables 146. The plurality of cables passes through a pre-heater 148. The plurality of cables passes through a loom roller 150. The loom roller 150 heats and/or applies pressure to portions of each cable to consolidate the plurality of cables 146 into a cable harness 152. The cable harness 152 then passes through an arc former 154. The arc former 154 imparts a curvature to the cable harness 152 to provide a curved cable harness 156.
[0145] In the FIG. 10 example each cable loom 140 provides a single cable strand 142, however in other examples each cable loom can provide a plurality of cable strands or cable bundle. The cable looms 140 are typically drums that have cable strands wrapped around them and rotate as the cable strand is fed off. In alternative examples another method of continuously providing cable strands may be used. The cable strands 142 are joined together into a plurality of cables 146, or cable bundle, at the cable join point 144. The cable join point 144 arranges the individual cable strands 142 into a position within the plurality of cables 142. The cable join point 144 may be a fixed structure or may include rollers and/or other features. The plurality of cables 146 is then fed through (or passed through or moved through or fed continuously through) the pre-heater 148. The pre-heater 148 heats a portion of the plurality of cables. The pre-heater 148 ensures that the plurality of cables 146 is already heated before entering the loom roller 150. Each cable or cable strand 142 may be of the construction claimed herein, for example that shown in FIG. 3a or FIG. 7.
[0146] The plurality of cables 146 is then fed through (or passed through or moved through or fed continuously through) the loom roller 150. The loom roller 150 is an example of a mould tool. The loom roller 150 applies heat and/or pressure to a portion of the plurality of cables such that the coatings of each cable consolidate into a common harness. The portion is the part of the plurality of cables 146 aligned with and/or located between the loom roller 150, and the portion will continuously and/or progressively move along the plurality of cables 146 as the plurality of cables 146 is fed through the loom roller 150. The loom roller 150 consolidates the plurality of cables 146 into a cable harness 152, for example comprising a common harness with embedded cable inners.
[0147] The cable harness 152 is then fed through (or passed through or moved through or fed continuously through) an arc former 154. The arc former 154 imparts a curve to the cable harness 154. The curve is achieved by, in the FIG. 10 example, two rollers of different diameter that apply different levels of strain to each side of the cable harness 152, due to their differing diameters. In other examples other methods of imparting an arc to a cable harness may be used. The resulting curved cable harness 156 may have a curve that corresponds to the curvature of the outside of a casing of a gas turbine engine, for example.
[0148] FIGS. 11a and 11 b shows the loom roller in more detail. For example, FIGS. 11a and 11b shows the loom roller 150 of FIG. 10. FIG. 11a shows a sectional view through the loom roller whilst a plurality of wires are being passed through the rollers. FIG. 11b shows the resulting cable harness.
[0149] FIG. 11a shows a loom roller top 160 with a roller top axis 162. FIG. 11a shows a loom roller bottom 164 with a roller bottom axis 166. A plurality of cables 170 are between the loom roller top 160 and the loom roller bottom 164. In the FIG. 11a example, there are five cables 170, however in other embodiments there may be a greater or less number of cables. Each cable has a cable inner 172 and a coating arrangement 174. The coating arrangement 172 may be according to, for example, the FIG. 3a example or the FIG. 7 example. In the FIG. 11a example, the cable inner 172 has two wires, however in other embodiments the cable inner 172 may have a different construction.
[0150] In the FIG. 11a example, the plurality of cables 170 are passing through the rollers along an axis perpendicular to the plane of the figure, i.e. in or out of the page. In the FIG. 11a example, the loom roller top 160 and loom roller bottom 164 are profiled. For example the loom roller top 160 has a reduction in radius towards its axial centre by including angled changes in outer radius. The loom bottom roller 164 has square changes in outer profile to provide a reduced radius towards its axial centre. The roller top axis 162 and roller bottom axis 166 are separated by a distance such that the profiled loom roller top 160 and profiled loom roller bottom 164 create a mould pocket 171 that corresponds to the outer shape of the plurality of cables. In the FIG. 11a example, the pocket 171 is slightly smaller than the outer profile of the plurality of cables 170. Being slightly smaller results in pressure being applied to the plurality of cables 170 as they pass through the rollers. The loom rollers may be heated, for example they may contain heating elements.
[0151] FIG. 11b shows a cable harness 178. The cable harness 178 comprises a plurality of cable inners 172 and a common harness 176.
[0152] In a method of manufacturing a cable harness the plurality of cables 170 are passed through the mould pocket 171 in the loom roller top 160 and loom roller bottom 164. The loom rollers 160, 164 apply heat to the plurality of cables 170 through the heated loom rollers, for example by heating elements in the loom rollers. The loom rollers apply pressure to the plurality of cables 170 due to the fact that the outer profile of the plurality of cables 170 is larger than the profile of the pocket 171. The loom rollers may optionally apply heat and/or pressure to the plurality of cables 170 under a vacuum. The heat and pressure applied by the rollers 160, 164 causes the coating arrangement 174 of each of the cables 170 to consolidate to form a common harness 176. The outer profile of the common harness 174 corresponds to the outer profile of the mould pocket 171. The cable inners 172 are arranged within the common harness 176 in positions that correspond to the arrangement of the plurality of wires 170 before passing through the loom roller 150.
[0153] FIG. 12 shows an embodiment of the harness 186 with a cross section shaped as an aerofoil. A plurality of cable inners 180 are arranged in an aerfoil shape. Heat treatable filler 182 is positioned around the cable inners 180 in order to ensure a smooth aerodynamic shape to the outer profile of the cross section. A coating 184 is applied around the aerofoil. The coating 184 may be metal, for example to provide a grounding plane or to protect the harness 186. The aerofoil shape may be achieved using a correspondingly shaped mould tool.
[0154] Advantageously the aerofoil shaped harness 186 may allow the harness to be placed in positions of air flow in a product, for example with minimal impact on the air flow. For example the harness may be passed through the bypass duct of a gas turbine engine.
[0155] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.
