Patent Publication Number: US-11657931-B2

Title: Method for manufacturing an electrical harness

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to French patent application No. FR 20 07329 filed on Jul. 10, 2020, the disclosure of which is incorporated in its entirety by reference herein. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of electrical harness manufacturing. Such electrical harnesses comprise at least one electric wire extending between at least two connectors. The electric wire or wires are also covered by at least one protective sheath helping protect the electric wire or wires from friction or any contact with a foreign object. 
     BACKGROUND 
     The connectors are intended to cooperate with electrical equipment or with other electrical harnesses and may be at least partially covered by shrink sleeves. Indeed, such shrink sleeves may be arranged so as to at least partially cover both an end of a protective sheath and a connector or so as to at least partially cover several portions of protective sheaths in the case of a branch joint. Once shrunk, these shrink sleeves seal these connections against dust and/or water. 
     Moreover, once the shrink sleeves have been shrunk during a contraction operation, for example a thermal contraction operation, or possibly during an operation for crosslinking an adhesive, a sealant or the like, the connectors and the at least one sheath are rigidly connected to each other. Therefore, the rotation of a connector relative to the longitudinal axis along which the at least one sheath extends may subject this sheath to torsional stress, and even plastic deformation when the shear stress exceeds a threshold value. 
     In the aeronautical field in general, such electrical harnesses are produced from a first physical prototype of a model electrical harness made directly on a model aircraft. Next, the model electrical harness is removed from the model aircraft and one or more specific tools are produced, such as counter-forms with which the model electrical harness cooperates in a complementary manner. 
     This type of specific tool is designed to hold the connectors during the phase of contracting the shrink sleeves, such that the connectors and/or the protective sheath are not deformed when the electrical harness is subsequently assembled on an aircraft. For this purpose, the tool has, at each of the connectors, a position and an orientation that are predetermined in advance, during the prototype phase. 
     This type of tool may form a sub-assembly, referred to a module, of a modular system used to manufacture a complete harness. 
     Generally, an operator arranges the different modules on a modular table in order to form a tooling system referred to, for convenience, as a “complete tool”, as opposed to the notion of a specific tool mentioned previously. The data sheet for manufacturing a harness lists the references of the different modules to be used and the respective locations where they need to be arranged on the modular table. 
     In particular, the modules constrain the relative angular orientation of the different connectors and the different branch joint sleeves relative to the longitudinal axis of the different branches of the electrical harness before the phase of contracting the shrink sleeves. 
     Such a complete tool makes it possible to process, in a single operation, all of the dimensional parameters of the electrical harness, such as, in particular, the length of the branches and the relative angular orientation of the connectors and the branch joint sleeves relative to the at least one protective sheath. 
     The angular values of the radial orientations of the connectors and the branch joint sleeves relative to the at least one protective sheath are not specified in the work document indicating the phases of manufacturing an electrical harness to the operator. Indeed, these angular values are defined and set by the different modules. 
     However, some modules may be specific to a particular type and orientation of connector or branch joint sleeve. The number of modules required may be considerable, depending on the number of different electrical connectors and branch joint sleeves to be positioned on the same electrical harness and the number of different electrical harnesses that can be manufactured for the same aircraft and/or for several different aircraft. This can give rise to problems in terms of storing and managing these different modules or in the case of specific complete tools that cannot be broken down into several modules. 
     Moreover, the time required to search for and position the various modules on the modular table is not insignificant. Similarly, once the manufacture of an electrical harness is complete, it may be necessary to remove all the modules from the modular table, identify them and store each one in a clearly marked location for possible future use. 
     Furthermore, such modules or specific complete tools also entail major financial costs associated with their development, design and production. Moreover, any modification in definition affecting the relative angular orientation of a connector in relation to a sheath entails modifying the module in question or the specific complete tool, which has an impact on the cost and the production cycle. 
     Finally, in the event of a problem assembling the electrical harness on an aircraft, it is not possible to determine the cause of the problem without removing the harness from the aircraft and without positioning it once more on the tool that acts as a template. 
     Documents JP 3 959 006 and U.S. Pat. No. 7,529,638 describe methods for manufacturing an electrical harness comprising at least three connectors and at least one branch joint with three branches. Such an electrical harness may then have three-dimensional geometry but is produced on a two-axis plane. Therefore, a manufacturing phase using a predetermined angle measured on this working plane is described. 
     However, a harness is manufactured flat with this predetermined angle between the three branches; the orientation of the different connectors relative to each sheath section can then be modified during the subsequent assembly by the other, differently oriented protective sheath sections. Shear stress generated by torsional stresses may therefore occur in the different branches on the protective sheath and/or on the connectors and the branch joints. 
     Document U.S. Pat. No. 9,090,215 relates to an electrical harness comprising a branch joint with three branches for orienting wires in a single predetermined relative orientation. 
     Document WO 2019/234080 relates to a tool ( 1 ) for modularly overmolding a cable strand ( 10 ) in order to produce a protective sheath along the entire length of the strand and thus form a harness. This tool ( 1 ) comprises complementary half-modules ( 2   a ;  3   a ;  4   a ) assembled into standard modules ( 2 ) and into branch joint modules extending respectively in the same median plane (PM) and, in suitable cases, in a direction (Z ′Z) outside this median plane (PM), the half-modules ( 2   a ;  3   a ;  4   a ) being in the overall shape of straight and angled blocks. Each half-module ( 2   a ;  3   a ;  4   a ) has an inner half-bore ( 9 ) forming, with the half-bore of the complementary half-module, a cylindrical bore surrounding the strand ( 10 ) along straight and angled sections ( 9 ), and a cylindrical double bore ( 9 ;  93 D) along sections of the strand ( 10 ) forming a branch joint ( 11 ). The adjacent half-modules ( 2   a ;  3   a ;  4   a ) of consecutive modules are coupled together by contiguous, detachable mechanical connections ( 7   a ;  7   b ). 
     This document WO 2019/234080 also describes a method for manufacturing an electrical harness comprising at least one electric wire and at least one protective sheath. Such a method comprises a step of injecting a primary sheathing material into the tool in order to fill the gap between the bore ( 9 ) of the overmolding modules and the strand ( 10 ). The method then comprises a step of heat treatment of the primary material in order to form the protective sheath. 
     Therefore, such a method makes it possible to shape the harness three-dimensionally, i.e., to produce bends or branch joints with predetermined angles for the different branches. 
     However, such a method does not allow the connectors and the branch joints to be oriented according to a twist angle of each branch, in particular at straight connectors. 
     Document FR 2 937 471 describes an electrical harness for an aircraft comprising a sealing sheath ( 40 ) arranged around an end zone ( 20 ′) of a metal braid ( 20 ) and a clamping collar ( 50 ). 
     Furthermore, in order to manufacture harnesses, the use of methods as described in documents EP 0 924 713, EP 3 480 909 or the article “Robotic Assembly of Automotive Wire Harnesses” published by Xin Yang on 1 Jul. 2014 and available on the website https://www.assemblymag.com/articles/92264-robotic-assembly-ofautomotive-wire-harnesses, is also known. Although these methods may comprise steps for immobilizing a connector or producing a seal, they do not make it possible to eliminate the torsional stresses in the sheaths, these stresses being generated when assembling the harness on an aircraft when the angular orientation of a connector, for example a female connector, does not match the angular orientation of a complementary male connector. 
     SUMMARY 
     The object of the present disclosure is therefore to propose an alternative manufacturing method that helps overcome the above-mentioned limitations. Moreover, such a manufacturing method can make it possible to dispense with the need for many different modules, or even a modular table for manufacturing different electrical harnesses. It also immobilizing helps limit, or indeed ensure the absence, of any torsional stress generated during the assembly of the electrical harness in the protective sheath or sheaths, the branch joints and/or the connectors. 
     The disclosure therefore relates to a method for manufacturing an electrical harness, this electrical harness comprising at least one reference member and at least one secondary member and at least one electric wire extending between the at least one reference member and the at least one secondary member. The harness comprises at least one protective sheath for protecting the at least one electric wire and at least two shrink sleeves, the at least two shrink sleeves comprising at least one reference shrink sleeve and at least one secondary shrink sleeve, the at least one reference shrink sleeve being arranged so as to at least partially cover the at least one reference member and the at least one protective sheath, the at least one secondary shrink sleeve being arranged so as to at least partially cover the at least one secondary member and the at least one protective sheath. 
     According to the disclosure, such a method is remarkable in that it comprises at least the following steps: 
     assembling of the at least one electric wire, the at least one protective sheath, the at least two shrink sleeves, the at least one reference member and the at least one secondary member, the at least two shrink sleeves being arranged in a non-contracted state; 
     in a reference portion of the electrical harness, reference contraction of the at least one reference shrink sleeve, the reference contraction step allowing the at least one protective sheath to be immobilized relative to said at least one reference member, the at least one reference member allowing the electrical harness to be assigned at least one reference plane; 
     in a secondary portion of the electrical harness different from the reference portion, angular positioning of the at least one secondary member relative to the reference plane according to a relative angular orientation, the relative angular orientation being defined in a plane perpendicular to a longitudinal direction OX along which the at least one protective sheath extends longitudinally opposite the at least one secondary member; 
     holding of the at least one secondary member in position in the relative angular orientation; and 
     secondary contraction of the at least one secondary shrink sleeve. 
     In other words, such a manufacturing method is applicable to any electrical harness comprising two connectors or more when this harness has branch joints. The reference member and the secondary member may be chosen indiscriminately from the group comprising the connectors and the branch joints. 
     The expression “shrink sleeve” may refer indiscriminately to a heat-shrink sleeve or any other type of sleeve for producing a seal at a connection between a reference member or a secondary member and a protective sheath. A shrink sleeve may thus comprise a sleeve secured by a bonding method by means of a bonding agent such as an adhesive or a sealant interposed between this sleeve, the reference or secondary member and the protective sheath. Another type of shrink sleeve may also be clamped mechanically onto the reference or secondary member and the protective sheath, such as a cable gland, for example. 
     The reference contraction of a shrink sleeve so as to at least partially cover the reference member and the at least one sheath helps constrain the reference member and the at least one protective sheath in rotation. The positioning of this reference member thus allows a reference plane of the electrical harness to be identified. 
     When the reference member is a straight connector, the reference plane may be defined as being a plane perpendicular to a radial direction passing, for example, through a key or a locating pin of the connector. 
     When the reference member is an angled connector, the reference plane may be defined as being a plane perpendicular to a radial direction passing through the bend of the connector or indeed as being a plane perpendicular to a projection of this radial direction passing through the bend on a transverse plane YOZ. 
     Finally, when the reference member is a branch joint, the reference plane may be defined as being a plane in which coplanar branches of the branch joint lie. 
     Such a manufacturing method therefore comprises one or more contraction steps referred to for convenience as “reference contraction” steps in order to be easily distinguished from one or more other contraction steps referred to for convenience as “secondary contraction” steps. Moreover, the expressions “reference contraction” and “secondary contraction” may consist in heating, bonding, sealing or indeed mechanically clamping a shrink sleeve comprising a cable gland onto the reference or secondary member and the protective sheath. These different contraction steps thus help provide tight sealing at the connections between a protective sheath and the reference or secondary member. 
     Such contraction steps are thus carried out in sequence one after another precisely in order, starting with a reference contraction followed by at least one secondary contraction. 
     Depending on information relating to relative angular orientations contained in a definition drawing of the electrical harness to be manufactured, an operator may then orient a secondary member such as, for example, a connector in the secondary portion of the electrical harness, relative to the protective sheath arranged opposite and therefore relative to the reference plane previously defined in the reference portion of the electrical harness. 
     As already indicated, the reference contraction and secondary contraction steps may, for example, be carried out by heating the shrink sleeves by means of a heating device, for example using an electrical resistance and a fan to generate a flow of air passing close to the heating resistance then conveyed towards a shrink sleeve. 
     The angular positioning and the holding of the at least one secondary member in position may be achieved in different ways, for example manually by an operator or by means of a tool capable of orienting the secondary member in a relative angular position of between 0 and 360 degrees around the longitudinal direction OX of the protective sheath. Such a relative angular position allows a specific twist angle to be defined for each branch or for each connector that may, in particular, have a locating pin. 
     Moreover, the relative angular orientation between the at least one secondary member and the reference plane may advantageously be read or noted by the operator in the definition drawing of the electrical harness to be manufactured. Pour each secondary member and each relative angular orientation, the operator may use a single tool in order to orient each secondary member in a different manner, one after another. 
     Advantageously, the method may comprise a preliminary step of determining the relative angular orientation. 
     Such a preliminary step may therefore be implemented in order to generate a definition drawing of the electrical harness and allow the operator to read or note the different relative angular orientation values to subsequently be given to at least one secondary member. 
     Such a preliminary step may moreover be implemented in different ways and, for example, by a simulation, tests, trials or calculations. 
     In practice, this preliminary step may be carried out by manufacturing a model electrical harness directly on a model aircraft, the model electrical harness being different from the electrical harness and comprising at least one model secondary member, at least one model reference member, at least one model electric wire extending between the at least one model secondary member and the at least one model reference member, at least one model protective sheath for protecting the at least one model electric wire and at least two model shrink sleeves, the at least two model shrink sleeves comprising at least one model reference shrink sleeve and at least one model secondary shrink sleeve, the at least one model reference shrink sleeve being arranged so as to at least partially cover the at least one model reference member and the at least one model protective sheath, the at least one model secondary shrink sleeve being arranged so as to at least partially cover the at least one model secondary member and the at least one model protective sheath. 
     In other words, the model electrical harness is a different electrical harness to that which is manufactured using the manufacturing method, but is dimensionally and structurally identical. The model electrical harness is manufactured prior to the electrical harnesses and allows an operator to produce a definition drawing of the electrical harnesses to subsequently be manufactured. 
     Moreover, this preliminary step may comprise the following sub-steps: 
     marking of a reference line on the at least one model protective sheath by means of marks arranged on the at least one model protective sheath; 
     preliminary assembling of the at least one model electric wire, the at least one model protective sheath, the at least two model shrink sleeves, the at least one model secondary member and the at least one model reference member, the at least two model shrink sleeves being arranged in a non-contracted state, the preliminary assembling sub-step being carried out on a working plane; 
     in a model reference portion of the model electrical harness, preliminary reference contraction allowing a model reference plane to be assigned to the model electrical harness, the model reference plane being defined by means of the marks arranged on the at least one model sheath; 
     positioning of the model electrical harness on the model aircraft and connection of at least one model secondary member with at least one piece of electrical equipment of the model aircraft; 
     in a model secondary portion of the model electrical harness different from the model reference portion, preliminary secondary contraction of the at least one model secondary shrink sleeve; and 
     measuring of the relative angular orientation between the marks arranged on the at least one model protective sheath and the at least one model secondary member. 
     In other words, the marking sub-step makes it possible to identify a straight orientation on the at least one model protective sheath. This marking may, for example, be achieved by adding marks to a standard sheath or indeed by using a sheath pre-equipped with such a reference line. 
     The model reference member is then oriented angularly relative to the sheath in order to define the model reference plane in the model reference portion. 
     In the model secondary portion, the model secondary member and the model protective sheath are then still free to pivot relative to each other and, therefore, no torsional stress is transmitted to the at least one model protective sheath. 
     Once the preliminary reference contraction has been carried out, the model protective sheath is immobilized relative to the model reference member and also relative to the model secondary member that is mounted on a piece of electrical equipment of the model aircraft. The preliminary secondary contraction therefore allows the relative angular orientation to be set between this model secondary member and the at least one model protective sheath. It is then optionally possible to disconnect the model secondary member from the electrical equipment. 
     According to a first embodiment of the disclosure, the sub-step of measuring the relative angular orientation may be implemented with the model electrical harness being left fully mounted on the model aircraft. 
     Indeed, a measuring tool may be used directly on the model aircraft in order to record the different angular orientations. Such a measuring sub-step then allows an operator to take a quick reading and allows the model electrical harness to then be used directly on the model aircraft. Only the model secondary member or members may be temporarily disconnected from the electrical equipment in order to carry out this measuring sub-step. 
     According to a second embodiment of the disclosure, the preliminary step may comprise a sub-step of removing the model electrical harness from the model aircraft, the sub-step of measuring the relative angular orientation being implemented after the removal sub-step. 
     In this scenario, the sub-step of removing the model electrical harness may allow an operator to carry out the measuring sub-step outside the model aircraft and therefore to measure relative angular orientations that are difficult to access, or even impossible to achieve, when the model electrical harness is mounted on the model aircraft. 
     Moreover, the at least one reference member may take several forms. 
     According to a first variant of the disclosure, the at least one reference member may comprise a reference connector, the at least one reference plane corresponding to a plane defined as a function of a position of the reference connector. 
     The position of the reference connector is determined by means of a reference relative angular orientation in relation to the at least one protective sheath. For example, the reference connector being substantially cylindrical and straight, a key or a locating pin provided on or in the reference connector thus makes it possible to identify its position prior to the reference contraction. Such a locating pin is therefore offset radially relative to a central axis of the reference connector. 
     According to another example, the reference connector may be angled at 90 degrees. In this case, the angular orientation of the bend in azimuth relative to the longitudinal direction OX of the protective sheath makes it possible to identify the orientation of the reference plane relative to this bend. 
     According to a second variant of the disclosure, the at least one reference member may comprise at least one branch joint with three branches, the at least one reference plane corresponding to a plane containing the three branches of the at least one branch joint with three branches. 
     In other words, the three branches of a branch joint are oriented in three coplanar directions defining the reference plane. 
     Moreover, the at least one reference member may comprise two branch joints with three branches comprising a first branch joint and a second branch joint, the at least one reference plane comprising a first reference plane and a second reference plane, the at least one reference shrink sleeve comprising a first reference shrink sleeve and a second reference shrink sleeve, the first reference shrink sleeve being arranged so as to at least partially cover at least one of the three branches of the first branch joint and the at least one protective sheath, the second reference shrink sleeve being arranged so as to at least partially cover at least one of the three branches of the second branch joint and the at least one protective sheath. 
     More specifically, the first and second reference shrink sleeves may respectively form two single-piece assemblies simultaneously covering the three branches of the first branch joint and the second branch joint. Two reference contraction steps are carried out in this scenario and allow a first reference plane then a second reference plane to be assigned to the different sections of the electrical harness. 
     The two reference contraction steps are carried out in a precise order that may, for example, be defined from left to right on a production drawing of the electrical harness. 
     Once the first reference contraction has been carried out on the reference shrink sleeve, two secondary contraction steps can be carried out on two secondary shrink sleeves cooperating with two protective sheaths. The third branch of the first branch joint cooperates with a first end of an intermediate protective sheath. The second end of this intermediate protective sheath cooperates with one of the three branches of the second branch joint. 
     In this case, the step of contracting the shrink sleeve arranged at the second branch joint is both a secondary contraction step with respect to the first reference step and a second reference step with respect to the other branches each cooperating with a secondary member formed by a connector. 
     Therefore, this second reference contraction step is then followed by two steps for angularly positioning the two secondary members relative to two protective sheaths, two steps for holding these secondary members and the protective sheaths in position and two secondary contraction steps for contracting the two secondary shrink sleeves that remain in a non-contracted state at the final two secondary members. 
     The object of the present disclosure is also a tool configured to at least angularly position and hold in position at least one secondary member relative to at least one protective sheath according to a relative angular orientation and to help manufacture an electrical harness according to the abovementioned method. 
     Such a tool may also be used to take the measurements of the relative angular orientation of the different secondary members of a model electrical harness. This tool also makes it possible to check the relative angular orientations once the electrical harness has been manufactured. Such a check may be advantageous, in particular, before assembling the electrical harness on an aircraft or during assembly if a problem is identified. 
     Moreover, such a tool may be used to check a relative angular orientation once the electrical harness is totally assembled on an aircraft without it needing to be removed from the aircraft. 
     Advantageously, such a tool may comprise: 
     a planar fixed plate; 
     at least one immobilizing device for immobilizing a protective sheath of the electrical harness and securing the protective sheath to the fixed plate; 
     a rotationally movable part that is able to rotate about an axis of rotation, the axis of rotation being arranged parallel to the fixed plate; 
     at least one immobilization support configured to immobilize the secondary member of an electrical harness and secure said secondary member with the movable part; and 
     a graduated angular scale for positioning the protective sheath and the secondary member according to the relative angular orientation. 
     The rotationally movable part thus allows a secondary member to be pivoted relative to the axis of rotation lying in the reference plane. 
     The reference plane is arranged parallel to the fixed plate of the tool. 
     In practice, the tool may comprise an angular locking means for locking the movable part in position relative to the fixed plate. 
     The secondary member is therefore held in angular position by means of this angular locking means. Such an angular locking means may, for example, comprise an indexing pin, a clamping piston, a ratchet device, etc. 
     According to another example, the tool may comprise at least one guide bearing for guiding the movable part in rotation relative to the fixed plate. 
     This or these guide bearings make it possible, in particular, to reduce the friction between the movable part and the fixed plate when the movable part is rotating. 
     Advantageously, the tool may comprise a fixed disk secured to the fixed plate, the fixed disk comprising, in order to indicate the relative angular orientation, either the graduated angular scale or a radial index intended to be arranged opposite the graduated angular scale. 
     In other words, the graduated angular scale or the radial index may be arranged on the fixed disk in order to allow an operator at least to position the secondary member according to the relative angular orientation. 
     Alternatively, or in addition, the movable part may comprise a movable disk comprising, in order to indicate the relative angular orientation, either said graduated angular scale or a radial index intended to be arranged opposite the graduated angular scale. 
     In this scenario, the axis of rotation of the movable disk coincides with an axis of revolution of the fixed disk. The rotation of the movable disk allows the radial index or the graduated angular scale to move respectively relative to the graduated angular scale or to the radial index. 
     In practice, the movable part may comprise a movable plate, the at least one immobilization support being mounted on the movable plate. 
     The positioning of such a movable plate on a movable disk may be adjustable in the plane defined by the movable disk. Such a movable plate may make it possible, for example, to adapt the position of an immobilization support depending on the type of secondary member to be immobilized. 
     The movable plate can also be retractable relative to the movable disk, for example in order to replace an immobilization support depending on the type of secondary member to be immobilized. Reversible securing means such as screws and/or nuts or a ball-and-spring locking system then allow the movable plate to be removed quickly. 
     Moreover, the fixed disk and the movable disk each have a through-hole allowing the secondary member and/or the protective sheath to pass through the tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure and its advantages appear in greater detail from the following description of examples given by way of illustration with reference to the accompanying figures, in which: 
         FIG.  1    is a perspective view of a first embodiment of an electrical harness manufactured according to a manufacturing method according to the disclosure; 
         FIG.  2    is a top view of a second embodiment of an electrical harness manufactured according to the manufacturing method according to the disclosure; 
         FIG.  3    is a perspective view of a third embodiment of an electrical harness manufactured according to the manufacturing method according to the disclosure; 
         FIG.  4    is another perspective view of a variant of the first embodiment of an electrical harness manufactured according to the manufacturing method according to the disclosure; 
         FIG.  5    is a logic diagram showing a first variant of the manufacturing method according to the disclosure; 
         FIG.  6    is a logic diagram showing a second variant of the manufacturing method according to the disclosure; 
         FIG.  7    is a perspective view of a model electrical harness manufactured in a preliminary step of the manufacturing method according to the disclosure; 
         FIG.  8   , is a diagram showing another example of a preliminary step of the manufacturing method according to the disclosure; and 
         FIG.  9    is a perspective view of a tool for manufacturing an electrical harness, according to the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As mentioned above, the disclosure relates to a method for manufacturing an electrical harness intended, for example, to equip an aircraft. The disclosure can also relate to a method for manufacturing an electrical harness in fields other than the aeronautics field. 
     Elements present in more than one of the figures may, if appropriate, be given the same references in each of them. 
     As shown in  FIG.  1   , such an electrical harness  30  comprises at least one electric wire  22  extending between a reference member  31  formed in this example by a straight connector and a secondary member  32  formed by an 90° angled connector in this variant of the first embodiment of an electrical harness  30 . 
     Such an electric wire  22  is moreover protected by a protective sheath  34 . A first end of this protective sheath  34  cooperates with the reference member  31  in a reference portion  131 . A second end of the protective sheath  34  cooperates with the secondary member  32  in a secondary portion  132 . 
     In order to tightly seal such an electrical harness  30 , shrink sleeves  36 ,  37  are also used and shown in  FIG.  1    in a non-contracted state. Thus, in a reference portion  131 , a reference shrink sleeve  36  is positioned so as to partially cover the reference member  31  and the protective sheath  34 . Similarly, in a secondary portion  132 , a secondary sleeve  37  is positioned so as to partially cover the secondary member  32  and the protective sheath  34 . 
     A reference contraction is then carried out on the reference shrink sleeve  36 , for example by heating the reference shrink sleeve  36 , in order to thermally shrink it and thus immobilize the protective sheath  34  relative to the reference member  31 . Therefore, this operation allows a reference plane P 1  to be defined. Such a reference plane P 1  is oriented in this instance perpendicular to a radial direction connected to the orientation of the reference member  31 . 
     The secondary member  32  is then capable of pivoting about a longitudinal direction OX by a relative angular orientation θ1 relative to the protective sheath  34 , and therefore relative to the reference plane P 1  that was previously assigned to it in the reference portion  131 . 
     Once oriented, the secondary member  32  and the protective sheath  34  are then held in position and a secondary contraction may be carried out on the secondary shrink sleeve  37 , for example by heating the secondary shrink sleeve  37  in order to shrink the secondary shrink sleeve  37 , so as to immobilize the secondary member  32  relative to the protective sheath  34  and to the reference plane P 1 . 
     As shown in  FIG.  2   , an electrical harness  40  according to a second embodiment comprises at least one electric wire  22 ,  22 ′ extending between a reference member  41  formed, in this example, by a branch joint with three coplanar branches and three secondary members  42 ,  42 ′,  42 ″ formed by straight or angled connectors. 
     Such an electric wire  22 ,  22 ′ is moreover protected by three sections of the protective sheath  44 ,  44 ′,  44 ″. A first end of each protective sheath  44 ,  44 ′,  44 ″ cooperates with the reference member  41  in a reference portion  141 . A second end of the protective sheath  44 ,  44 ′,  44 ″ cooperates with each secondary member  42 ,  42 ′,  42 ″ in a secondary portion  142 ,  142 ′,  142 ″. 
     As above, shrink sleeves  46 ,  47 ,  48 ,  49  are also positioned on this electrical harness  40  in a non-contracted state. Thus, in a reference portion  141 , a reference shrink sleeve  46  is arranged so as to partially cover the reference member  41  and the protective sheath  44 ,  44 ′,  44 ″. Similarly, in the three secondary portions  142 ,  142 ′,  142 ″, secondary sleeves  47 ,  48 ,  49  are arranged so as to partially cover the three secondary members  42 ,  42 ′,  42 ″ and the three sections of the protective sheath  44 ,  44 ′,  44 ″. 
     A reference contraction is then carried out by heating the reference shrink sleeve  46  in order to immobilize each section of the protective sheath  44 ,  44 ′,  44 ″ relative to the reference member  41 . A reference plane P 2  is thus defined depending on the position of the three branches of the branch joint forming the reference member  41 . 
     Each secondary member  42 ,  42 ′,  42 ″ is then capable of pivoting about a longitudinal direction OX by a relative angular orientation θ1 in relation to the associated section of the protective sheath  44 ,  44 ′,  44 ″ and therefore in relation to the reference plane P 2  that was previously assigned to it in the reference portion  141 . 
     Once oriented, these secondary members  42 ,  42 ′,  42 ″ and respectively the sections of the protective sheath  44 ,  44 ′,  44 ″ are then held in position and secondary contractions may be carried out on the secondary shrink sleeves  47 ,  48 ,  49 . 
     Similarly, and as shown in  FIG.  3   , a third embodiment of an electrical harness  50  may also comprise several reference members  51 ,  51 ′ formed in this example by two branch joints with three coplanar branches and five secondary members  52 ,  52 ′,  52 ″,  53 ,  53 ′. Moreover, the reference member  51 ′ and the secondary member  52 ′ are in this instance combined. The secondary members  52 ,  52 ″,  53  and  53 ″ are formed by straight or 90° angled connectors, for example. 
     Five sections of the protective sheath  54 ,  54 ′,  54 ″,  55  and  55 ′ protect the electric wires of the electrical harness  50 . A first reference member  51  is arranged in a first reference portion  151 . A second reference member  51 ′ is arranged in a second reference portion  151 ′. 
     As above, the shrink sleeves  56 ,  57 ,  58 ,  59 ,  60 ,  61  are positioned on this electrical harness  50  in a non-contracted state. Thus, in the reference portion  151 , a first reference shrink sleeve  56  is arranged so as to partially cover the reference member  51  and the protective sheath  54 ,  54 ′,  54 ″. Similarly, in the three secondary portions  152 ,  152 ′,  152 ″, first secondary sleeves  57 ,  58 ,  59  are arranged so as to partially cover the three first secondary members  52 ,  52 ′,  52 ″ and the three sections of the protective sheath  54 ,  54 ′,  54 ″. 
     A first reference contraction is then carried out by heating the first reference shrink sleeve  56 , immobilizing each section of the protective sheath  54 ,  54 ′,  54 ″ with respect to the first reference member  51  and thus defining a first reference plane P 3  depending on a position of the three branches of the branch joint forming the first reference member  51 . 
     Each first secondary member  52 ,  52 ′,  52 ″ is then capable of pivoting about a longitudinal direction OX by a relative angular orientation θ1 relative to each section of the protective sheath  54 ,  54 ′,  54 ″ and therefore relative to the first reference plane P 3  that was previously assigned to it in the first reference portion  151 . 
     Once oriented, these first secondary members  52 ,  52 ′,  52 ″ and respectively the sections of the protective sheath  54 ,  54 ′,  54 ″ are then held in position and first secondary contractions may be carried out on the first secondary shrink sleeves  57 ,  58 ,  59 . 
     The first secondary shrink sleeve  59  then also forms a second reference shrink sleeve  59 . A second reference contraction is then carried out, immobilizing each section of the protective sheath  55 ,  55 ′ with respect to the second reference member  51 ′ combined with the first secondary member  52 ′. A second reference plane P 4  is thus defined depending on the position of the three branches of the branch joint forming the second reference member  51 ′. 
     Each second secondary member  53 ,  53 ′ is then capable of pivoting about a longitudinal direction OX by a relative angular orientation θ1 relative to the associated section of the protective sheath  55 ,  55 ′ and therefore relative to the second reference plane P 4  that was previously assigned to it in the second reference portion  151 ′. 
     Once oriented, these secondary members  52 ,  52 ′,  52 ″ and respectively the sections of the protective sheath  54 ,  54 ′,  54 ″ are then held in position and second secondary contractions may be carried out on the second secondary shrink sleeves  60 ,  61 . 
     The different shrink sleeves  56 - 61  are shown here in their contracted state to ensure the electrical harness  50  is tightly sealed. 
     As shown in  FIG.  4   , the relative angular orientation θ1 may, for example, be read conventionally in the clockwise direction relative to a transverse direction OY perpendicular to the longitudinal direction OX. The relative angular orientation θ1 is then read in a transverse plane YOZ defined by two transverse directions OY and OZ perpendicular to each other and relative to the longitudinal direction OX. 
     Such a transverse plane YOZ is also arranged perpendicular to the reference plane P 1  defined at the reference member  31 . 
     As shown in  FIGS.  5  and  6   , such an electrical harness is manufactured by implementing a specific manufacturing method  1 ,  10 . 
     According to a first variant of the manufacturing method shown in  FIG.  5   , the method  1  comprises a step  2  of assembling the electric wire or wires  22 ,  22 ′, the at least one protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′, the at least two shrink sleeves  36 - 37 ,  46 - 49 ,  56 - 61 , the at least one reference member  31 ,  41 ,  51 ,  51 ′ and the at least one secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′. 
     During this assembly step  2 , the at least two shrink sleeves  36 - 37 ,  46 - 49 ,  56 - 61  remain arranged in a non-contracted state. 
     Next, in a reference portion  131 ,  141 ,  151 ,  151 ′ of the electrical harness  30 ,  40 ,  50 , a reference contraction step  3  is carried out on a reference shrink sleeve  36 ,  46 ,  56 ,  59 . Such a reference contraction step  3  thus allows the electrical harness  30 ,  40 ,  50  to be assigned at least one reference plane P 1 , P 2 , P 3 , P 4 . Moreover, the reference portion  151 ′ may be defined at a later stage, namely after a first reference contraction step  3 . The reference shrink sleeve will therefore be contracted during a second reference contraction step  3 . 
     Thus, the reference plane P 4  can be determined once the reference plane P 3  has been assigned. 
     Therefore, in the secondary portion or portions  132 ,  142 ,  142 ′,  142 ″,  152 ,  152 ′  152 ″,  153 ,  153 ′ of the electrical harness  30 ,  40 ,  50  relative to the reference portion  131 ,  141 ,  151 ,  151 ′, one or more steps  4  are implemented in order to angularly position the secondary member or members  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ relative to the at least one protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ and therefore relative to a reference plane P 1 , P 2 , P 3 , P 4 . 
     As indicated above, the secondary portion or portions  153 ,  153 ′ of the electrical harness  50  can only be assigned at a later stage after having determined the reference plane P 4  at the reference portion  151 ′. Thus, the steps  4  of angularly positioning the secondary members  53 ,  53 ′ relative to the portions of the protective sheath  55  and  55 ′ are also carried out once the reference plane P 4  has been allocated to the electrical harness  50 . 
     Such an angular positioning  4  is carried out according to the relative angular orientation θ1 as described in  FIG.  4    in the transverse plane YOZ perpendicular to a longitudinal direction OX along which the protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ extends longitudinally. 
     For example, in this variant, a key or a locating pin  38  of the secondary member  32  is initially assembled during the assembly step  2  in a vertical position matching the transverse direction OY. The angular positioning step  4  then consists in rotating a secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ on itself about the longitudinal direction OX in order to position the locating pin  38 , the bend of an angled connector when the secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ is formed by an angled connector  32 ,  42 ,  42 ″,  53 ′ or indeed the plane defined by the branches of a branch joint when the secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ is formed by a branch joint  52 ′. 
     Such a bend is therefore formed by a portion of the connector extending radially relative to the longitudinal direction OX. This bend may, for example, be oriented at an angle of 90° relative to the longitudinal direction OX, but other values may also be envisaged for this angle. In this case, the relative angular orientation θ1 is then assigned to a projection of the bend in a plane perpendicular to the longitudinal direction OX. 
     The manufacturing method  1  then comprises a step  5  of holding the secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ in position in the relative angular orientation θ1. 
     Finally, a secondary contraction step  6  is carried out on the secondary shrink sleeves  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′. 
     According to a second variant of the manufacturing method shown in  FIGS.  6  and  8   , the method  10  may comprise a preliminary step  11 ,  11 ′ of determining the relative angular orientation θ1. This preliminary step  11 ,  11 ′ is thus implemented prior to the assembly step  12 , the reference contraction step  13 , the angular positioning step  14 , the step  15  of holding in position and the secondary contraction step  16 . The preliminary step  11 ,  11 ′ therefore consists in manufacturing a model electrical harness  230  on a model aircraft. This model electrical harness  230  is identical to the electrical harness  30 ,  40 ,  50  that needs to be manufactured according to the manufacturing method  1 ,  10 . 
     This preliminary step  11 ,  11 ′ comprises a sub-step  110 ,  110 ′ of marking a reference line on a model protective sheath  234  as shown in  FIG.  7   . This marking step  110 ,  100 ′ is carried out by means of marks  235  arranged on this model protective sheath  234 . 
     The preliminary step  11 ,  11 ′ next comprises a preliminary sub-step  111 ,  111 ′ of assembling a model electric wire  222 , the model protective sheath  234 , two model shrink sleeves  236 ,  237 , a model reference member  231  and a model secondary member  232 . During this preliminary sub-step  111 ,  111 ′, the two model shrink sleeves  236 ,  237  are arranged in their non-contracted state. Such a preliminary assembling sub-step  111 ,  111 ′ is moreover carried out on a working plane. 
     The preliminary step  11 ,  11 ′ then comprises a preliminary reference contraction sub-step  112 ,  112 ′ for assigning a model reference plane P 5  to the model electrical harness  230 . This preliminary reference contraction sub-step  112 ,  112 ′ is also carried out on the working plane in a model reference portion  331  of the model electrical harness  230 . Moreover, such a model reference plane P 5  is defined by means of the marks  235  arranged on the model protective sheath  234 . 
     Therefore, only the model shrink sleeve  236  is arranged in its contracted state, whereas the model shrink sleeve  237  remains arranged in its non-contracted state. 
     The preliminary step  11 ,  11 ′ next comprises a sub-step  113 ,  113 ′ of positioning the model electrical harness  230  on the model aircraft and connecting the model secondary member  232  formed by a connector with at least one piece of electrical equipment of the model aircraft. 
     In a model secondary portion  332  of the model electrical harness  230  different from the model reference portion  331 , a preliminary secondary contraction sub-step  114 ,  114 ′ is next carried out on the model secondary shrink sleeve  237 , followed by a sub-step  115 ,  115 ′ of measuring the relative angular orientation θ1 between the marks  235  and the model secondary member  232 . 
     Such a measuring sub-step  115 ,  115 ′ may be implemented in different ways. 
     For example, as shown in  FIG.  6   , this sub-step  115  of measuring the relative angular orientation θ1 may be implemented with the model electrical harness  230  being left fully mounted on the model aircraft. Optionally, only the model secondary member  232  may be temporarily disconnected from the electrical equipment with which it cooperates. 
     Alternatively, and as shown in  FIG.  8   , the preliminary step  11 ′ may comprise a sub-step  116 ′ of removing the model electrical harness  230  from the model aircraft. The sub-step  115 ′ of measuring the relative angular orientation θ1 is then implemented after the removal sub-step  116 ′. 
     As shown in  FIG.  9   , the disclosure also relates to a tool  70  allowing at least one secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ to be angularly positioned and held in position relative to at least one protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ according to a relative angular orientation θ1. Such a tool  70  can then be used to help manufacture an electrical harness  30 ,  40 ,  50  according to the method  1 ,  10  as previously described. 
     This tool  70  therefore comprises a planar fixed plate  71  and at least one immobilization device  72  for immobilizing a protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ of the electrical harness  30 ,  40 ,  50  and secure the protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ to the fixed plate  71 . 
     The tool  70  also comprises a movable part  73  capable of pivoting about an axis of rotation AXROT arranged parallel to the fixed plate  71 . Such an axis of rotation AXROT is thus intended to coincide with a longitudinal direction OX of the protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′. 
     Furthermore, at least one immobilization support  74  is configured to immobilize a secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ of the electrical harness  30 ,  40 ,  50  and constrain this secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ in rotation with the movable part  73 . 
     The tool  70  also comprises a graduated angular scale  75  for positioning the protective sheath  34 ,  44 ,  44 ′,  44 ″,  54 ,  54 ′,  54 ″,  55 ,  55 ′ and the secondary member  32 ,  42 ,  42 ′,  42 ″,  52 ,  52 ′,  52 ″,  53 ,  53 ′ according to the relative angular orientation θ1. 
     Moreover, such a tool  70  may advantageously comprise an angular locking means  76  for locking the movable part  73  in position relative to the fixed plate  71 . Such an angular locking means  76  may in particular be in the form of an indexing pin cooperating with at least one hole or at least one notch of complementary shape. 
     According to another example, the tool  70  may comprise at least one guide bearing  77  for guiding the movable part  73  in rotation relative to the fixed plate  71 . 
     The tool  70  may also comprise a fixed disk  78  secured to the fixed plate  71 . As shown, such a fixed disk  78  may comprise the graduated angular scale  75  for indicating the relative angular orientation θ1. 
     The movable part  73  may comprise a movable disk  80  comprising, in order to indicate the relative angular orientation θ1, a radial index  79  intended to be arranged opposite the graduated angular scale  75 . According to another example not shown here, the movable part  73  may comprise a movable disk  80  comprising, in order to indicate the relative angular orientation θ1, the graduated angular scale  75 . In this case, the radial index  79  may be arranged on the fixed plate  71  or indeed on a part secured to the fixed plate  71 . 
     This movable part  73  may comprise a movable plate  81  on which the immobilization support or supports  74  are mounted. 
     Furthermore, such a tool  70  may also be used to take a measurement of the relative angular orientation θ1 on a model electrical harness  230 . Once the electrical harness  30 ,  40 ,  50  has been manufactured, the tool  70  may be used to check one or more relative angular orientations θ1 before this electrical harness  30 ,  40 ,  50  is assembled on an aircraft or indeed during or after assembly if, for example, a problem is identified. 
     Naturally, the present disclosure is subject to numerous variations as regards its implementation. Although several implementations are described above, it should readily be understood that an exhaustive identification of all possible embodiments is not conceivable. It is naturally possible to replace any of the means described with equivalent means without going beyond the ambit of the present disclosure.