Housing for telecommunications cable winding

Abstract

Housing for Telecommunications Cable Winding This description relates to a housing (150) for winding cable (107) comprising: – a base (103); – a cable winding reel (105) mounted for rotation relative to the base; – a receiving plate (109) for at least one pre-terminated cable assembly (111), the plate being mounted for rotation coaxially with the reel; and – elements for locking the angular position of the plate relative to the reel. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Housing for winding telecommunications cable technical field

[0001] This description relates generally to telecommunications installations, and more particularly to optical branch points (OBPs) intended to allow optical fiber connection between devices in an optical network. Previous technique

[0002] Various types of optical branching points have been proposed. In the case of an installation in a residential building, the optical branching point is said to be "internal" and is, for example, installed in the building on a landing outside the residential apartments.

[0003] One drawback of existing optical distribution points, particularly indoor optical distribution points, is that their implementation requires the installer to perform time-consuming and highly delicate operations which, in the event of delays or handling errors, result in lost revenue for the company employing the installer and subscriber dissatisfaction. Furthermore, the installer is required to use specific equipment and train operators. Summary of the invention

[0004] There is a need to improve existing optical branch points and existing methods for installing optical branch points.

[0005] In particular, there is a need to simplify the operations carried out by an installer during the installation and wiring, or connection, of an optical branch point.

[0006] For this purpose, one embodiment provides a cable winding box comprising: - a base; - a cable winding spool mounted to rotate relative to the base; - a receiving plate for at least one pre-connectorized assembly of the cable, the plate being mounted to rotate coaxially with the reel; and - elements for locking the angular position of the plate relative to the coil.

[0007] According to one embodiment, the elements for locking the angular position of the wafer relative to the coil comprise, on the coil side, at least two annularly distributed orifices and, on the wafer side, at least one lug.

[0008] According to one embodiment, the coil comprises, on either side of a cable receiving hub, a first flange on the base side and a second flange on the plate side.

[0009] According to one embodiment, the orifices are located on the periphery of the second flange.

[0010] According to one embodiment, the plate is intended to be rotated relative to the coil so that said at least one pre-connectorized assembly is approximately opposite at least one cable exit of the housing.

[0011] According to one embodiment, the plate is intended to receive several pre-connectorized assemblies aligned and intended to be respectively facing several cable outputs of the housing.

[0012] According to one embodiment, the plate includes a hinge-forming thinning and notches located in an external ring of the plate, in line with the thinning.

[0013] According to one embodiment, the housing further includes elements for locking the angular position of the coil relative to the base.

[0014] According to one embodiment, the elements for locking the angular position of the coil relative to the base and the elements for locking the angular position of the plate relative to the coil are arranged so that each angular locking position of the coil relative to the base corresponds to an angular locking position of the plate relative to the coil in which the pre-connectorized assembly(ies) are approximately opposite the cable exit(s) of the housing.

[0015] According to one embodiment, the elements for locking the angular position of the coil relative to the base comprise, on the coil side, a toothed wheel and, on the base side, a locking button adapted to be translated coaxially to the coil and cooperating with the toothed wheel.

[0016] According to one embodiment, the number of orifices is equal to the number of notches of the toothed wheel, the orifices being aligned radially with respect to the notches.

[0017] One embodiment provides an optical branching point comprising: - the housing as described above; and - an optical cable wound on the reel and comprising first and second ends intended to be connected respectively to the outside of the housing and to at least one pre-connectorized assembly.

[0018] One embodiment provides a method for installing the optical branch point as described above, the method comprising the following successive steps: a) unwinding of the optical cable by pulling on its first end causing a rotation of the reel and the plate around the axis of rotation of the reel, said at least one lug being located in a first orifice among said at least two orifices; b) disengagement of said at least one lug from the first orifice, by deformation of the plate; c) rotation of the plate relative to the coil; and d) engagement of said at least one lug in a second orifice among said at least two orifices.

[0019] According to one embodiment, in step c), the plate is rotated relative to the coil so that the pre-connectorized assembly(ies) are approximately opposite the cable exit(s) of the housing.

[0020] According to one embodiment, the method further comprises, using the elements for locking the angular position of the coil relative to the base: - prior to step a), a step to release the rotation of the coil relative to the base; and - between steps a) and b), a step of blocking the rotation of the coil relative to the base. Brief description of the drawings

[0021] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0022] [Fig.1] is an exploded perspective view of an optical branching point according to one embodiment;

[0023] Figures 2, 3, 4, 5, 6, 7 and 8 are perspective views illustrating successive steps in a method of installing the optical branch point of Figure 1 according to one embodiment; and

[0024] [Fig.9] is a perspective view of part of the optical branching point of [Fig.1], Description of the implementation methods

[0025] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0026] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the various applications of the boxes for winding telecommunications cable of this description and the various devices that may incorporate these boxes have not been detailed, the embodiments described being compatible with all or most common applications and with all or most common devices implementing at least one box for winding telecommunications cable, possibly subject to adaptations within the reach of a person skilled in the art upon reading this description.

[0027] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0028] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0029] Unless otherwise specified, the expressions "approximately", "about", "substantially", and "in the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0030] Unless otherwise specified, the expression "in contact with" means "in mechanical contact with".

[0031] One of the objectives of the described embodiments is to provide an intermediate, or indoor, optical branching point. The intermediate optical branching point of this description is, for example, intended to be connected upstream to another optical branching point, such as a building distribution box or a floor distribution box. The intermediate optical branching point includes, for this purpose, a pre-connectorized cable extension. The intermediate optical branching point of this description is also intended to be connected downstream to one or more pre-connectorized optical termination points (OTPs).

[0032] The intermediate optical branching point of this description is, for example, intended to be installed on a landing of a building outside a residential dwelling, for example an apartment, belonging to a subscriber to a fiber optic network. The intermediate optical branching point, also called a floor box (BE) or landing box (BDP), connects, for example, optical termination points (PTOs) installed in each dwelling to a vertical network point in the building, for example a building box or a floor box. In the case of a house, the optical branching point is called an "external" optical branching point (PBOE). It is installed, for example, in a cabinet or on an overhead support. The external optical branching point is typically used to connect houses. Individual optical termination points (OTPs) are designed to be installed in residential dwellings and allow a subscriber to access offers and services provided by a company that operates the optical network to which an optical terminal is connected. The optical branch point described here, for example, is designed to connect OTPs located on the same floor, or even all the OTPs in a building.

[0033] The installation and connection of the optical cable presents a challenge for the installer, as the optical cable, containing for example a plurality of optical fibers, is fragile and can easily be damaged by improper handling. In particular, connecting the optical fibers within the cable to plugs or connector sockets or fittings carries a high risk of breakage or malfunction, due, for example, to the need to perform cleaving, fusion splicing, etc., of the optical fiber.

[0034] Furthermore, there is a wide variety of buildings where the optical branching point may be installed. In order to adapt to the different situations encountered, the intermediate optical branching point of this description is intended to contain a pre-terminated optical cable of sufficient length to allow connection of the optical branching point in most cases, for example to a building or floor box separated from the intermediate optical branching point by a variable distance from one floor to another.

[0035] The described embodiments provide a housing for winding a "pre-connected" or "pre-connectorized" cable, i.e., one equipped with connectors or even splices, at least one end of each fiber prior to winding it into the housing. This saves time during the installation and connection of the optical branch point on site and significantly reduces the risk of handling errors.

[0036] Furthermore, the described embodiments provide a housing comprising a base and a cable winding reel, allowing for the attachment of a cable extension, as well as elements to prevent the reel from rotating relative to the base. These locking elements have the advantage of allowing only the length of cable necessary for connecting to the optical branch point to be unwound, thus avoiding excessive cable slack outside the optical branch point. This helps prevent the risk of breakage, for example, if the cable were to get caught.

[0037] The [Fig. 1] is an exploded perspective view of an optical branching point 100 according to one embodiment.

[0038] In the example shown, the optical branch point 100 comprises: - a base 103; - a reel 105 mounted to rotate relative to the base 103 and on which an optical cable 107 is wound; - a receiving plate 109 for at least one pre-connectorized assembly 111, comprising a connector and a cable fitting 107, mounted to rotate coaxially to the reel 105; - elements 113 for locking the angular position of the plate 109 relative to the coil 105; - a button 115 for locking the angular position of the coil 105 relative to the base 103; and - a cover 117, or hood.

[0039] The base 103, the coil 105, the plate 109, the button 115 and the cover 117 are, for example, made of plastic. In this case, each of these elements is, for example, manufactured by plastic injection molding.

[0040] The optical cable 107 comprises, for example, a plurality of optical fibers, for example twelve optical fibers (so-called "12 FO" optical cable).

[0041] In the example shown, the base 103 comprises: - openings, for example oblong holes, allowing the base to be fixed to a support such as a wall, for example by means of screws and plugs; - a substantially cylindrical hub 119 on which the coil 105 is inserted and around which the coil can rotate when the rotation is not blocked by the button 115; - elements 121, or lugs, for holding the coil 105 on the hub 119, so that once the coil 105 is coupled to the hub 119 it can no longer translate along its axis of rotation (vertical axis, in the orientation of [Fig.l]); - an external ring 123 for holding the cable 107 around the reel 105; - a cable guide element 125 for cable 107; and - fixing elements for cover 117, for example clips.

[0042] In the illustrated example, coil 105 comprises: - a lower flange 131 located on the base side 103, the flange 131 being able to consist of a solid disc, a perforated disc, or a set of radial fins; and - an upper flange 133 located on the cover side 117 and allowing passage of a portion of the cable 107, at the end of which is located a separator 135 commonly referred to by its Anglo-Saxon name "FanOut," from which a fiber whip emerges.

[0043] The reel 105 is, for example, intended to receive a reserve of pre-terminated optical cable forming an optical cable extension.

[0044] Most of the cable 107 is wound on a hub, or drum, of the reel 105, on either side of which are located the flanges 131 and 133. The cable 107 is intended to be partially unwound outside the housing 100 for connection to a floor box (BPE) or building branch point (PBI). A very small part of the cable 107 is intended to remain inside the box and forms, for example, less than one turn located above the upper flange 133.

[0045] In the example shown, the plate 109, or fitting support plate, includes: - a retaining element for the separator 135; - a retaining element 137 intended to receive several pre-connectorized assemblies 111 aligned and intended to be positioned respectively opposite several cable outlets 139 of the housing; and - fins for holding the fiber bundle.

[0046] As an alternative, a retaining element intended to receive a single pre-connectorized assembly 111 is provided.

[0047] In the upper part, the coil 105 further includes a toothed wheel 147, or gear wheel, intended to cooperate with the button 115. The toothed wheel 147 is for example formed in the lower flange 131.

[0048] In the illustrated example, the button 115 has teeth, or lugs, intended to be engaged in spaces, or grooves, located between the notches, or teeth, of the toothed wheel 147. To prevent the rotation of the coil 105, i.e. to lock its angular position, relative to the base 103, the button 115 further comprises a substantially parallelepiped-shaped lower part, extending vertically along a direction orthogonal to a disc-shaped upper part under which are located the teeth intended to be engaged in the toothed wheel 147, the lower part of the button 115 being intended to fit into a slot formed in the upper part of the hub 119, between the retaining elements 121. This corresponds to a blocked, or locked, position of the coil 105.In an unlocked position of the coil 105, the teeth of the knob 115 are disengaged from the spaces between the notches of the wheel 147 and the lower part of the knob 115 is disengaged from the slot in the hub 119. This frees the rotation of the coil 105 relative to the hub 119 carried by the base 103. As an example, the knob 115 has four teeth arranged in a cross shape.

[0049] The button 109 is for example held together with the base 103 by a pin, or lug, of the base which fits into a groove in the button 115. This makes the button 115 “unlosable”.

[0050] The elements for locking the angular position of the coil 105 relative to the base 103, including the wheel 147 and the button 115, can be made differently from that illustrated in [Fig. 1]. Moreover, these locking elements are optional.

[0051] The base 103 includes, for example, holes and / or cutouts allowing plugs located at optical cable ends each comprising a single optical branch fiber, for example, to an optical termination point (OTP).

[0052] The base 103, the reel 105, the plate 109, the button 115 and the cover 117 of the optical branch point 100 are part of a housing 150 for winding telecommunications cable.

[0053] The cover 117 is mechanically linked to the base 103 by a hinge.

[0054] Although [Fig.1] illustrates an example in which the guiding element 125 is, in front view, located on the right side of the optical branching point, this example is not limiting and the guiding element 125 may, as an alternative, be located on the left side.

[0055] Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 and Fig. 8 are perspective views illustrating successive steps of a method for installing the optical branch point 100 of Fig. 1 according to one embodiment.

[0056] Fig. 2 illustrates a state of the optical branch point 100 before or after fixing to a support (not shown), for example a wall, and before connection.

[0057] At this stage, the cover 117 is closed and the cable 107 is entirely contained within the optical branch point 100. The assemblies 111 are pre-connectorized or pre-wired, that is to say that each optical fiber of the cable 107 carries, for example, a connector, or a plug, inserted into one of the fittings inside the optical branch point 100.

[0058] Fig. 3 illustrates a further step of opening the cover 117 of the optical branch point 100.

[0059] The button 115 is for example in a pressed, or engaged, position in which it locks the angular position of the coil 105 relative to the base 103.

[0060] The cable 107 has, at its end opposite the pre-connectorized assemblies 111 and intended to be pulled out of the optical branch point 100, a pulling sock 301. The cable 107 is engaged in the guide element 125, in the vicinity of the pulling sock 301.

[0061] Figure 4 illustrates a subsequent step in unlocking the angular position of the coil 105 relative to the base 103. For this purpose, a disengagement operation of the button 115 is implemented so as to free the rotation of the coil 105 relative to the base 103. More specifically, the button 115 is translated upwards, coaxially with the coil 105, for example by applying a pull (arrow 400) along a substantially vertical axis. This causes the teeth of the button 115 to disengage from the grooves of the gear 147 carried by the coil 105.

[0062] Figure 4 further illustrates a subsequent step of pulling (arrow 401) the cable 107 out of the optical branch point 100 by its end fitted with the pulling sock 301. During this step, pulling the cable 107 causes a rotation (arrow 403) of the coil 105 relative to the base 103. The housing 150 includes elements for locking the angular position of the plate 109 relative to the coil 105. These elements will be described in more detail below.

[0063] During the rotation of the coil 105, the angular position of the plate 109 relative to the coil 105 is locked so that the plate 109 remains fixed to the coil 105. Thus, the plate 109 (and the pre-connectorized assembly(ies) 111 that it carries) rotates relative to the base 103 at the same time as the coil 105. The portion of the cable 107 initially wound on the hub of the coil 105 is at least partially unwound from the coil 105 under the action of the cable 107 being pulled, without hindering and / or damaging the various pre-connectors of the cable 107.

[0064] Figure 5 illustrates a later step in which a length of cable 107 sufficient to allow connection has been unwound from the reel 105. In the illustrated example, the pre-connectorized assemblies 111 carried by the plate 109 are not facing the cable exits 139. This makes subsequent wiring of the assemblies 111 difficult, or even impossible.

[0065] In order to overcome this problem, one embodiment provides the possibility of rotating the plate 109 without rotating the coil 105, to allow the pre-connectorized assemblies 111 to be positioned opposite the cable outlets 139 without changing the length of cable 107 unwound.

[0066] Fig. 6 illustrates a further step in locking the angular position of the coil 105 relative to the base 103. During this step, the angular position of the coil 105 relative to the base 103 is locked by engaging the teeth of the button 115 in the grooves of the gear 147. More specifically, the button 109 is translated downwards (arrow 601), coaxially with the coil 105, for example by exerting a push along a substantially vertical axis.

[0067] Once the position of the coil 105 is locked relative to the base 103, the angular position of the plate 109 relative to the coil 105 is unlocked so that the plate 109 can rotate independently of the coil 105. The plate 109 (and the pre-connectorized assemblies 111 that it carries) is then rotated (arrow 603) relative to the coil 105 (therefore relative to the base 103) until the assembly(ies) 111 are substantially opposite the cable outlets 139.

[0068] In practice, the plate 109 is for example deformed to release one or more lugs carried by an underside of the plate 109 and each inserted into an orifice of the upper flange 133 of the coil 105. The plate 109 is then rotated and the lug(s) are inserted into other orifices of the upper flange 133 corresponding to a position of the plate 109 for which the pre-connectorized assemblies 111 are opposite the outputs 139.

[0069] The order of operations represented by arrows 601 (locking the angular position of the coil relative to the base) and 603 (rotation of the plate relative to the coil) can be reversed.

[0070] Fig. 7 illustrates a later step in which optical cables, each comprising a single optical fiber, are connected, by means of plugs, to the pre-connectorized assemblies 111 carried by the plate 109. The fact that the assemblies 111 are opposite the outputs 139 greatly simplifies this operation.

[0071] Figure 8 illustrates a state in which the optical branching point 100 is closed. The cover 117 thus protects the internal components of the optical branching point 100 from external aggressions (shocks, dust, water, etc.). Openings in a lower lateral face of the base 103 allow the cable 107 and the optical cables connected to the pre-terminated assemblies 111 to exit. These optical cables are, for example, each connected to a PTO.

[0072] Fig. 9 is a perspective view of the coil 105, the plate 109 and the button 115.

[0073] The lower flanges 131 and upper flanges 133 of the coil 105 are, for example, manufactured separately and then assembled.

[0074] In the example shown, the toothed wheel 147 of the coil 105 has a repeated hollow geometry corresponding to a counter-form of the geometry of teeth or notches 901 located in the lower part of the button 115.

[0075] The button 115 is translatable along a defined stroke, greater than the height of the notches of the toothed wheel 147. When the teeth of the button 115 are not in contact with the grooves of the wheel 147, rotation of the spool 105 relative to the base 103 is possible. Conversely, when the teeth of the button 115 are in contact with the grooves of the wheel 147, rotation of the spool 105 relative to the base 103 is impossible.

[0076] The button 115 has a geometry allowing bistable behavior, for example by means of deformable lateral parts (curved sides of a vertical part of the button 115 intended to be inserted into the base 103).

[0077] The upper flange 133 of the coil 105 includes at least two orifices distributed annularily around the periphery of the upper flange 133 and intended to receive each one lug 905, or pin, of the plate 109.

[0078] The plate 109 further includes a hinge-forming thinning 907 and notches 909 located in an outer ring 911 of the plate 109, extending from the thinning. During angular repositioning of the plate 109 relative to the reel 105 after unwinding the optical cable 107, this facilitates the bending of the portion of the plate 109 bearing the lugs 905 relative to the portion of the plate 109 located near the axis of rotation, particularly in a case where the plate 109 is blocked in translation relative to the coil 105 and the base 103.

[0079] The plate 109 is, for example, made of a single piece, for example of plastic, for example produced by injection molding. It combines a function of retaining the pre-connectorized assemblies 111 and of blocking rotation relative to the coil 105.

[0080] Advantageously, the button 115, the locking elements of the angular position of the coil 105 relative to the base 103 and the locking elements of the angular position of the plate 109 relative to the coil 105 are arranged so that each angular locking position of the coil relative to the base corresponds to an angular locking position of the plate relative to the coil in which the pre-connectorized assembly(ies) 111 are located approximately opposite the cable outlets 139 of the housing 150. For this purpose, for example, a number of holes 903 equal to the number of notches of the toothed wheel 147 is provided, the holes 903 being aligned radially with respect to the notches.

[0081] In the illustrated example, twelve notches on the coil 105 allow twelve different possible positions of the coil 105 relative to the base 103, and twelve orifices 903 allow twelve different possible positions for the plate 109 (comprising two lugs 905) relative to the coil 105.

[0082] One advantage of the described embodiments is that the operations required to install the optical branch point 100 are fewer and easier than with existing optical branch points. Furthermore, no on-site fiber optic connectorization is required during the installation of the optical branch point 100.

[0083] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will be apparent to those skilled in the art. In particular, what is set forth more specifically in relation to an application example in which the telecommunications cable is an optical cable applies more generally to any type of telecommunications cable.

[0084] Finally, the practical implementation of the described embodiments and variants is within the reach of a person skilled in the art, based on the functional specifications given above. In particular, the described embodiments are not limited to the specific examples of materials and dimensions mentioned in this description.

Claims

Demands

1. Housing (150) for winding cable (107) comprising: - a base (103); - a cable winding reel (105) mounted for rotation relative to the base; - a receiving plate (109) for at least one pre-connectorized assembly (111) of the cable, the plate being mounted for rotation coaxially with the reel; and - elements for locking the angular position of the plate relative to the reel.

2. Housing (150) according to claim 1, wherein the elements for locking the angular position of the wafer (109) relative to the coil (105) comprise, on the coil side, at least two annularly distributed orifices (903) and, on the wafer side, at least one lug (905).

3. Housing (150) according to claim 2, in which the reel (105) comprises, on either side of a cable receiving hub, a first flange (131) on the base side (103) and a second flange (133) on the plate side (109).

4. Housing (150) according to claim 3, in which the orifices (905) are located on the periphery of the second flange (933).

5. Housing (150) according to any one of claims 1 to 4, wherein the plate (109) is intended to be rotated relative to the coil (105) so that said at least one pre-connectorized assembly (111) is approximately opposite at least one cable exit (139) of the housing.

6. Housing (150) according to claim 5, in which the plate (109) is intended to receive several pre-connectorized assemblies (111) aligned and intended to be respectively opposite several cable outlets (139) of the housing.

7. Housing (150) according to any one of claims 1 to 6, wherein the plate (109) comprises a hinge-forming thinning (907) and notches (909) located in an outer ring (911) of the plate, in line with the thinning.

8. Housing (150) according to any one of claims 1 to 7, further comprising elements for locking the angular position of the coil (105) relative to the base (103).

9. Housing (150) according to claim 8 in its dependence on claim 5 or 6, wherein the locking elements for the angular position of the coil (105) relative to the base (103) and the locking elements for the angular position of the plate (109) relative to the coil are arranged so that each angular locking position of the coil relative to the base corresponds to an angular locking position of the plate relative to the coil in which the pre-connectorized assembly(ies) (111) are located approximately opposite the cable exit(s) (139) of the housing.

10. Housing (150) according to claim 8 or 9, wherein the elements for locking the angular position of the coil (105) relative to the base (103) comprise, on the coil side, a toothed wheel (147) and, on the base side, a locking button (115) adapted to be translated coaxially to the coil and cooperating with the toothed wheel.

11. Housing (150) according to claim 10 in its dependence on claim 2, wherein the number of orifices (903) is equal to the number of notches of the toothed wheel (147), the orifices being aligned radially with respect to the notches.

12. Optical branch point (100) comprising: - the housing (150) according to any one of claims 1 to 11; and - an optical cable (107) wound on the reel and comprising first and second ends intended to be connected respectively to the outside of the housing and to at least one pre-connectorized assembly (111).

13. A method for installing the optical branch point (100) according to claim 12 in dependence on claim 2, the method comprising the following successive steps: a) unwinding the optical cable (107) by pulling on its first end causing rotation of the reel (105) and the plate (109) about the axis of rotation of the reel, said at least one lug (905) being located in a first orifice among said at least two orifices (903); b) disengaging said at least one lug from the first orifice by deforming the plate (109); c) rotating the plate about the reel; and d) engagement of said at least one lug in a second orifice among said at least two orifices.

14. A method according to claim 13 in its dependence on claim 5 or 6, wherein, in step c), the plate (109) is rotated relative to the coil (105) so that the pre-connectorized assembly(ies) (111) are approximately opposite the cable exit(s) (139) of the housing (150).

15. A method according to claim 13 or 14 as dependent on claim 8, the method further comprising, using the elements for locking the angular position of the coil (105) relative to the base (103): - prior to step a), a step of releasing the rotation of the coil (105) relative to the base (103); and - between steps a) and b), a step of blocking the rotation of the coil (105) relative to the base (103).

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