Patent Description:
Couplings are used in a wide variety of applications to transfer torque from one rotary component (such as a shaft) of one piece of equipment to a rotary component of another. Common considerations in coupling design include achieving satisfactory dynamic stress resistance and low friction in operating conditions varying across the operation envelope, as well as limiting costs. In aeronautic applications, minimizing weight is also typically a significant design consideration. The individual pieces of equipment can be manufactured separately. Many couplings require to align the axes of the two rotary components within a certain degree of tolerance, to a point which can be difficult or challenging to achieve in practice, and increasing the degree of tolerance to misalignment has represented significant trade-offs or sacrifices on at least some of the design considerations. There always remains room for improvement, such as addressing misalignment tolerance considerations.

<CIT> discloses a method and tooling for partial disassembly of a bypass turbofan engine.

<CIT> discloses a tool for fixing an outer collar of an intermediate casing of a turbomachine.

<CIT> discloses a rotational vibration damper.

<CIT> discloses a universal joint coupling.

According to an aspect of the present invention, there is provided a tool for installing segments of a coupling provided in accordance with claim <NUM>.

Optionally, and in accordance with the above, the diameter (D2) of the peripheral wall is greater than a diameter (D1) of a peripheral wall of the female coupler minus two times a length of the segments defined between opposed radial ends of the segments such that the radially inner ends of the segments are circumferentially offset from radially outer ends of the segments.

Optionally, and in accordance with any of the above, a handle protrudes from the peripheral wall and away from the coupler-engaging section.

Optionally, and in accordance with any of the above, the tool is made of a material having a hardness being less than that of a material of the female coupler.

Optionally, and in accordance with any of the above, the coupler-engaging section is sized to be engaged to the female coupler via an intermediary component.

Optionally, and in accordance with any of the above, the intermediary component is an anti-rotation nut secured to the female coupler, the coupler-engaging section is sized to be received within a bore defined through the anti-rotation nut.

According to another aspect of the present invention, there is provided a kit comprising the tool as described above and the segments, and optionally the female coupler and/or a male coupler of the couplers.

According to another aspect of the present invention, there is provided a method of assembling a coupling having a female coupler, a male coupler, and segments for engaging the female coupler to the male coupler, comprising: engaging a tool inside the female coupler to radially support the tool relative to the female coupler; inserting the segments between a peripheral wall of the female coupler and the tool, the tool radially supporting inner ends of the segments; and removing the tool and engaging the male coupler to the segments. The tool may have any or all of the features described above (and claimed in any claims <NUM> to <NUM>) in relation to the previous aspect of the present invention.

Optionally, and in accordance with the above, the engaging of the tool includes inserting a coupler-engaging section of the tool inside a bore of the female coupler.

Optionally, and in accordance with any of the above, the inserting of the segments between the peripheral wall of the female coupler and the tool includes inserting the segments between the peripheral wall and the tool having a diameter (D2) greater than a diameter (D1) of the peripheral wall of the female coupler minus two times a length of the segments defined between opposed radial ends of the segments.

Optionally, and in accordance with any of the above, the inserting of the segments includes angling the segments such that the segments are non-parallel relative to a radial direction relative to a rotation axis of the coupling.

Optionally, and in accordance with any of the above, the inserting of the segments includes sliding the inner ends of the segments into correspondingly shaped sockets defined by the tool.

Optionally, and in accordance with any of the above, the tool is rotated until a first segment of the segments is receivable within first connections of the female coupler and within a first socket of the sockets of the tool.

Optionally, and in accordance with any of the above, the rotating of the tool includes rotating the tool after the tool is engaged inside the female coupler.

Optionally, and in accordance with any of the above, the inserting of the segments includes inserting retaining tabs of the segments within gaps defined between the peripheral wall of the female coupler and a retaining ring.

Optionally, and in accordance with any of the above, the removing of the tool includes pulling on the tool in an axial direction relative to a rotation axis of the coupling.

Optionally, and in accordance with any of the above, the segments is radially locked relative to the female coupler before the removing of the tool.

Optionally, and in accordance with any of the above, the radially locking of the segments includes radially locking the segments with a retaining ring abutting retaining tabs of the segments.

<FIG> illustrates an aircraft engine depicted as a gas turbine engine <NUM> of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication a fan <NUM> through which ambient air is propelled, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section <NUM> for extracting energy from the combustion gases. The fan <NUM>, the compressor section <NUM>, and the turbine section <NUM> are rotatable about a central axis <NUM> of the gas turbine engine <NUM>. In the embodiment shown, the gas turbine engine <NUM> comprises a high-pressure spool having a high-pressure shaft <NUM> drivingly engaging a high-pressure turbine 18A of the turbine section <NUM> to a high-pressure compressor 14A of the compressor section <NUM>, and a low-pressure spool having a low-pressure shaft <NUM> drivingly engaging a low-pressure turbine 18B of the turbine section to a low-pressure compressor 14B of the compressor section <NUM> and drivingly engaged to the fan <NUM>. It will be understood that the contents of the present disclosure may be applicable to any suitable engines, such as turboprops and turboshafts, and reciprocating engines, such as piston and rotary engines without departing from the scope of the present disclosure.

In the embodiment shown, the low-pressure shaft <NUM> is drivingly engaged to an accessory <NUM>. The accessory may be, for instance, a generator, a gearbox, a pump, and so on. In the present case, a coupling <NUM> is used to transmit a rotational input from the low-pressure shaft <NUM> to the accessory <NUM>. The coupling <NUM> may allow the removal of the accessory <NUM>, either for maintenance or for substitution for another accessory. The coupling <NUM> is further described in <CIT>, the entire contents of which are incorporated herein by reference in their entirety.

Referring to <FIG>, the coupling <NUM> is described in more details. In the embodiment shown, the coupling <NUM> has two rotary members <NUM>, <NUM>, presented here in the form of shafts, and is used generally for the function of transferring torque from one of the rotary members <NUM> to the other <NUM>. Each of the two rotary members <NUM>, <NUM> is connected to a respective one of a female coupler <NUM> and a male coupler <NUM>. There can be some degree of misalignment (e.g. angle α) which may need to be accommodated between the axes of these rotary members <NUM>, <NUM>. The rotary member <NUM> may be drivingly engaged to the low-pressure shaft <NUM> via a spline coupling. Other couplings are contemplated. In some embodiments, the rotary member <NUM> may be made monolithic with the low-pressure shaft <NUM>.

In the embodiment shown, the female coupler <NUM> defines a recess <NUM> that is circumscribed by a peripheral wall <NUM> extending around a rotation axis of the coupling <NUM>, which, in the present case, corresponds to the central axis <NUM>. The rotation axis may be different than the central axis <NUM> in some embodiments. The peripheral wall <NUM> forms a radially inner-facing surface that will be referred to herein as more concisely as the inner face <NUM>. The male coupler <NUM> has a peripheral wall <NUM> extending around the rotation axis <NUM>. The peripheral wall <NUM> forms a radially outer-facing surface, or outer face <NUM>, that is received into the recess <NUM>. The outer face <NUM> has a smaller diameter than the inner face <NUM>, and a spacing <NUM> is present between the inner face <NUM> and the outer face <NUM>. The peripheral wall <NUM> of the female coupler <NUM> defines a plurality of connections 35A. The peripheral wall <NUM> of the male coupler <NUM> defines a plurality of connections 37A. In the present embodiment, these connections 35A, 37A are sockets having a substantially cylindrical shape and are interspaced with ridges or crests 35B, 37B. Other shapes are contemplated.

A plurality of circumferentially arranged links or segments <NUM> occupy the spacing <NUM>. Each segments <NUM> has an radially inner end <NUM> connected to the inner face <NUM>, and an radially outer end <NUM> connected to the outer face <NUM>. The inner end <NUM> is engaged to a respective one of the connections 37A of the peripheral wall <NUM> of the male coupler <NUM>. The outer end <NUM> is engaged to a respective one of the connections 35A of the peripheral wall <NUM> of the female coupler <NUM>. A shape of the radially inner end <NUM> and of the radially outer end <NUM> are selected to matingly engage the connections 35A, 37A. The connections 35A, 37A are used to prevent the radially inner end <NUM> and the radially outer end <NUM> from circumferentially sliding along the inner face <NUM> and the outer face <NUM> they are connected to, and thereby fix the relative circumferential position between the inner end <NUM> and the outer end <NUM>. The connection can be pivotal, rigid, or pivotal with a partial rigidity. Different types of connections can be used in different embodiments. Depending of the exact choice of connection type, the segment-receiving connections formed in the inner face and the outer face can involve a corresponding form of irregularity in the surface geometry. The irregularity can be in the form of a seat such as a protrusion, recess, or other shape complementary to the shape of the corresponding end, or in the form of a slot or hole to receive a pivot pin, to name some possible examples. The segments extend obliquely, in the sense that the general orientation L of their length between the inner end <NUM> and the outer end <NUM> is inclined, or slanted, e.g. by angle β, from the radial orientation R. In other words, the outer end of each segment is circumferentially offset from the segment's inner end by an arc A. In other the radially inner end <NUM> is circumferentially offset from the radially outer end <NUM> relative to the rotation axis A1.

In the embodiment shown, the segments <NUM> are pivotally engaged within their connections 35A, 37A. The pivotal connections may be provided via engagement between rounded ends of the segments <NUM> and the matching connections 35A, 37A in the form of rounded sockets in the inner face <NUM> and the outer face <NUM>. In an alternate embodiment, for instance, the pivotal connection can be achieved via an axially protruding pin in each one of the ends, and a corresponding slot to receive the pin tips on both axial sides of the segment, for instance. In still another embodiment, the connections can be provided in the form of rounded protrusions formed in the corresponding one, or both, of the inner face and the outer face, and a rounded recess of a matching shape can be formed in the corresponding end or ends of the segment, thereby inversing the male/female roles, to name another possible example.

In some embodiments, connections which allow for pivoting of the segments around one or both ends can be preferred, whereas in other embodiments, non-pivotal, or partially pivoting connections which cause bending deformation in the segment in addition to compressive stress may be preferred. The connections which are part of the male member may be referred to as the male member connections and the connections which are part of the female member can be referred to as the female member connections for simplicity.

The segments <NUM> are configured to work in compression during torque-transfer operation, and transfer torque by a combination of their compression stress (there can also be some degree of bending stress if the connection is not purely pivotal) and of their inclination/obliqueness β. In an embodiment where the female coupler <NUM> is the driving member, the inner end <NUM> of each segments <NUM> will be circumferentially offset from the outer end <NUM> in the direction of the torque T, which results in compressing the segments <NUM>. In an alternate embodiment where the male coupler <NUM> is the driving member, the outer ends <NUM> of the segments <NUM> would instead be circumferentially offset from the inner ends <NUM> in the direction of application of the torque T, which would also result in compressing the segments during torque transfer. Accordingly, the direction in which the inner ends <NUM> are circumferentially offset from the outer ends <NUM> may be selected as a function of the orientation of the torque T, and of whether the female coupler <NUM> or the male coupler <NUM> is the driving member, with the goal of subjecting the segments to compression during torque transfer.

The segments <NUM> may be configured in a manner to operate collectively, but as independent bodies from the point of view of stress gradients. The segments <NUM> may be separate individual components, mechanically connected to one another only indirectly, via the male coupler <NUM> and the female coupler <NUM>. By operating partially or fully in compression, and by being shaped and sized appropriately, they may each independently transfer a portion of the torque, without individually imparting shear or tensile stress into an adjacent segment. They may be relatively slender (i.e. thin in the orientation normal to their length in a transverse plane), which can allow them to elastically deform to a greater extend than, thicker components, or than a component forming a full annulus. This may contribute in accommodating a satisfactory degree of axial misalignment α between the male coupler <NUM> and the female coupler <NUM>. Moreover, the segments <NUM> can have an axial dimension, referred to herein as width W, which is significant relative to their length, such as in the same order of magnitude, similar or greater dimensions, to spread the compressive force along the width W. Spreading a given amount of compressive force (stemming from a given amount of torque T) along a greater width W, can limit the compressive force density, and allow a greater amount of torsion between the two axially opposite sides. In some embodiments, the torsion deformation capability of the segments can be harnessed to accommodate misalignment. In yet some other embodiments, it can be preferred to segment the segments into two or more components along their axial length, allowing the individual components to work independently from another, without transmitting torsion stress from one component of the segment to the adjacent other one. The width W can be significantly greater than the thickness, for instance. The coupling <NUM> can be designed in a manner for the full width to remain in contact with both of the female coupler <NUM> and the male coupler <NUM> due to deformation. The segments <NUM> can accommodate misalignment by deformation rather than by displacement relative to the members, which can be favorable from the point of view of wear resistance. In other embodiments it can be preferred to reduce the width W as much as possible in a manner to reduce weight, for instance.

In some embodiments, an even greater degree of axial misalignment may be accommodated by selecting, for the material of the segments <NUM>, a material having a Young's modulus significantly lower than the Young's modulus of the material forming the female coupler <NUM> and the male coupler <NUM>. For instance, in a scenario where the female coupler <NUM> and the male coupler <NUM> are made of steel, the segments can be made of a suitable plastic. A plastic material with greater viscoelastic behavior can be preferred to accommodate rapid overload, but may be less performant in terms of recovery factor at slower loading rates. Polyimide plastic materials such as Vespel™ may be an interesting candidate due to features such as heat resistance, and can have a Young's modulus two degrees or magnitude lower (~<NUM> times lower) than the Young's modulus of steel. Depending on the embodiment, other materials can be selected, such as other plastics, structured materials like metal foams, aerogels, and 3D-printed un-isotropic metal lattices which provide a low apparent Young modulus and even be more suitable at higher temperature environments. Similarly, lower cost materials than Vespel™ may be preferred in lower temperature environments.

Another potential reason for selecting a different material for the segments than for the male and female members is that it may be preferred for the material of the segment to have a greater coefficient of thermal expansion than the coefficient of thermal expansion of the male and female members. Indeed, in cases where the typical operation temperature range of the coupling is significantly above ambient temperature/standard atmospheric conditions, having a greater coefficient of thermal expansion can simplify assembly. Indeed, the length of the segments can be designed to be shorter that the distance between the members which they are designed to occupy during operation conditions. Accordingly, the segments can be inserted easily into the spacing, with some degree of play allowed at, say, <NUM>, and be designed to grow and extend as the temperature rises during normal operation, in a manner to stabilize in an equilibrium configuration where the combination of thermal growth and deformation from mechanical stress lead to maintaining a given design slant angle β at a given set of conditions of torque and temperature, and depart from this target slant angle within set tolerances as the torque and temperature vary within the operation envelope. Similarly, and the thermal "shrinking" can be harnessed at disassembly, to avoid the phenomena of worn parts becoming "hooked" on others, especially in blind assemblies.

The slant angle β can also affect the density of the compressive stress. In one embodiment, it can be preferred to optimize the slant angle β in a manner to minimize compressive stress density. In a scenario where it is also preferred to limit backlash to within <NUM> degrees, it can be preferred to select a slant angle of between <NUM> and <NUM> degrees measured from the outer pitch diameter tangent, with the range of between <NUM> and <NUM> degrees being more preferred in some embodiments. The ideal slant angle can be of <NUM> degrees in one embodiment, for instance. In other words, the angle β can be of between <NUM> and <NUM> degrees, preferably between <NUM> and <NUM>, and ideally of about <NUM> degrees.

Referring more particularly to <FIG>, in the embodiment shown, the segments <NUM> extend between a first axial end face <NUM> at a first axial end and a second axial end face <NUM> at a second axial end and opposite the first axial end face <NUM>. Each of the segments <NUM> includes each a first tab <NUM> axially protruding from the first axial end face <NUM> and away form the second axial end face <NUM>, and a second tab <NUM> axially protruding from the second axial end face <NUM> and away from the first axial end face <NUM>. The first tab <NUM> and the second tab <NUM> are engaged by a first retaining ring <NUM> and by a second retaining ring <NUM> of the female coupler <NUM>, respectively. The first tab <NUM> and the second tab <NUM> may be off-centered relative to a mid-plane intersecting both of inner ends <NUM> and outer ends <NUM> of the segments <NUM> and intersecting the first axial end face <NUM> and the second axial end face <NUM>. In other words, the segment <NUM> may be non-symmetric.

The peripheral wall <NUM> of the female coupler <NUM> defines notches. Namely, each of the crests 35B defines a first notch 35C and a second notch 35D axially spaced apart form the first notch 35C relative to the rotation axis A1. The first notch 35C is sized to receive the first retaining ring <NUM>. The second notch 35D is sized to receive the second retaining ring <NUM>. The first tab <NUM> is disposed radially between the first retaining ring <NUM> and the peripheral wall <NUM> of the female coupler <NUM>. The second tab <NUM> is disposed radially between the second retaining ring <NUM> and the peripheral wall <NUM> of the female coupler <NUM>. The first retaining ring <NUM> and the second retaining ring <NUM> bias the first tab <NUM> and the second tab <NUM> radially outwardly against the peripheral wall <NUM> and are used to maintain the segments <NUM> in engagement within their connections 35A.

Referring now to <FIG>, in the embodiment shown, the female coupler <NUM> may be splined to the low-pressure shaft <NUM> and retained engaged to the low-pressure shaft <NUM> via a bolt <NUM>. A threading engagement may be defined between the female coupler <NUM> and the bolt <NUM>. To prevent the bolt <NUM> from unthreading, an anti-rotation nut <NUM> is engaged to both of the bolt <NUM> and the female coupler <NUM>. The anti-rotation nut <NUM> has a first section 61A received radially between the female coupler <NUM> and the bolt <NUM> and a second section 61B that axially abuts against the bolt <NUM>. The second section 61B defines one or more locking tab(s) 61C that is axially received within a correspondingly shaped slot <NUM> defined by the female coupler <NUM>. Hence, the anti-rotation nut <NUM> is non-rotatable relative to the female coupler <NUM>. The female coupler <NUM> defines an annular groove <NUM> sized to accept a snap ring (not shown) to axially lock the anti-rotation nut <NUM> to the female coupler <NUM>. The anti-rotation nut <NUM> defines a bore 61D.

In some cases, for instance when the central axis <NUM> of the gas turbine engine <NUM> is substantially parallel to a ground, it may be difficult to insert the segments <NUM> without them falling down by gravity. A tool <NUM> is being described herein and may be used to assemble the segments <NUM> during an assembly process. The tool <NUM> described below may at least partially alleviate these drawbacks.

Referring now to <FIG>, the tool <NUM> has a fore section <NUM>, also referred to as a coupler-engaging section, that is used for securing the tool <NUM> to the female coupler <NUM>. In the embodiment shown, the fore section <NUM> is cylindrically shaped and is sized to be received within the bore 61D of the anti-rotation nut <NUM>. Peripheral walls of the fore section <NUM> and of the bore 61D may contact each other such that the tool <NUM> may remain substantially immobile relative to the female coupler <NUM> by itself thanks to the cooperation of the fore section <NUM> and the bore 61D. A tight fit may be provided therebetween. It will be appreciated that the tool <NUM> may include any suitable means for supporting the tool relative to the female coupler <NUM> about a rotation axis of the coupling <NUM> without departing from the scope of the present disclosure. For instance, the tool may define one or more prongs receivable within the slots <NUM> of the female coupler <NUM>, a shaft section receivable within an aperture of the female coupler <NUM> or within a hollow passage of a shaft to which the female coupler <NUM> is engaged. In some cases, the tool may engage an outer face of the female coupler <NUM>.

In the embodiment shown, the tool <NUM> includes a handle <NUM> via which a user can manipulate the tool to insert the fore section <NUM> inside the female coupler <NUM>. The fore section <NUM> and the handle <NUM> are located at opposite side of a central section <NUM> of the tool <NUM>. In the depicted embodiment, the central section <NUM> is sized to axially overlap the peripheral wall <NUM> of the female coupler <NUM>. The central section <NUM> has a peripheral wall 73A that defines connections 73B, shown as sockets, that have shapes that substantially correspond to the shape of the connections 37A defined by the peripheral wall <NUM> of the male coupler <NUM>. Hence, the tool <NUM> is used to simulate the presence of the male coupler <NUM> to ease assembly of the segments <NUM>.

The peripheral wall 73A of the tool <NUM> is therefore used as an abutting surface against which the radially inner ends <NUM> rest after their outer ends <NUM> they have been inserted into the connections 35A of the peripheral wall <NUM> of the female coupler <NUM>. In one variant, the central section <NUM> of the tool <NUM> may be a cylinder against which the inner ends <NUM> of the segments <NUM> rest. In other words, the central section <NUM> of the tool <NUM> need not define sockets or connections.

As shown in <FIG>, in the embodiment shown, to properly angle the segments <NUM> for subsequent insertion of the male coupler <NUM>, a diameter D2 of the peripheral wall 73A of the central section <NUM> of the tool <NUM> is greater than a diameter D1 of the peripheral wall <NUM> of the female coupler <NUM> minus two times a length of the segments <NUM>. This may ensure that the segments <NUM> are non-parallel to a radial direction relative to the central axis <NUM> and that the outer ends <NUM> of the segments are circumferentially offset form the inner ends <NUM> of the segments <NUM> when they are inserted in to the connections 35A of the female coupler <NUM>. In other words, this diameter D2 of the peripheral wall 73A of the tool <NUM> may be selected such that the segments <NUM> have the desired angle that they will have when the male coupler <NUM> is engaged to the segments <NUM>. The length of the segments <NUM> extends from their inner ends <NUM> to their outer ends <NUM>. It will be appreciated that the diameters D1 and D2 are taken from deepest most locations of the connections or sockets. In other words, the diameters D1, D2 do not extend from the crests that bound the sockets, but extends from locations between the crests.

The tool <NUM> may be made of a material having a hardness being less than that of a material of the female coupler <NUM>. For instance, the female coupler <NUM> may be made of a metallic material whereas the tool <NUM>, or at least the peripheral wall 73A of the tool <NUM>, may be made of plastic or any other suitable material sufficiently soft to avoid damaging the female coupler <NUM>. Different parts of the tool <NUM> (e.g., fore section <NUM>, handle <NUM>, and central section <NUM>) may be made of different material.

Referring now to <FIG>, the steps used to assemble the couplings <NUM> are illustrated. As shown in <FIG>, the tool <NUM> is engaged to the female coupler <NUM> to radially support the tool relative to the female coupler <NUM>. As explained above, this may be done by moving the tool <NUM> along a first axial direction A1 relative to the central axis <NUM> and relative to the female coupler <NUM>. In the embodiment shown, the tool <NUM> is supported by the fore section <NUM> being received into the bore 61D defined by the anti-rotation nut <NUM>. But, other means of radially supporting the tool <NUM> relative to the female coupler <NUM> are contemplated as explained above. Moreover, the tool <NUM> need not be directly engaged to the female coupler <NUM> and may be engaged to the female coupler <NUM> via an intermediary component, such as the anti-rotation nut <NUM> in the present embodiment.

As shown in <FIG>, once the tool <NUM> is in place, the segments <NUM> may be inserted into the connections 35A of the female coupler <NUM>. The segments <NUM> may be moved in the first axial direction A1 relative to the female coupler <NUM> to insert the outer ends <NUM> into the connections 35A. In the present case, the inner ends <NUM> are inserted into the connections 73B that are defined by the central section <NUM> of the tool <NUM>. Because the length of the segments <NUM> between their inner ends <NUM> and outer ends <NUM> is greater than a distance along a radial direction relative to the central axis <NUM> between the tool <NUM> and the peripheral wall <NUM> of the female coupler <NUM>, the segments <NUM> may be angled to be non-parallel to the radial direction before being slid into the connections 35A of the female coupler <NUM> and into the connections 73B of the tool <NUM>. As explained above, the tool <NUM> need not define the connections 73B and may define a cylindrical surface against which the inner ends <NUM> of the segments <NUM> may abut.

The first retaining ring <NUM> may be inserted into the corresponding notches defined by the peripheral wall <NUM> of the female coupler <NUM> before the tool <NUM> is engaged to the female coupler <NUM>. Hence, when the segments <NUM> are inserted into the connections 35A, they may be inserted until the first tabs <NUM> of the segments <NUM> are received radially between the peripheral wall <NUM> of the female coupler <NUM> and the first retaining ring <NUM>.

As shown in <FIG>, once all of the segments <NUM> are in place within the connections 35A of the female coupler <NUM>, the tool <NUM> may be disengaged. This may be done by moving the tool <NUM> along a second axial direction A2 being opposed to the first axial direction A1. In the present case, the second retaining ring <NUM> is inserted into the corresponding notches defined by the peripheral wall <NUM> of the female coupler <NUM> before the tool <NUM> is removed. However, in some cases, once all of the segments <NUM> have been inserted into the connections 35A, they may cooperate with one another to radially maintain themselves radially relative to the female coupler <NUM>. Hence, in some cases, it may be possible to install the second retaining ring <NUM> after the tool <NUM> has been removed. In some cases, it may be possible to install a given number (e.g. half) of the segments and then remove the tool <NUM>. The segments installed may cooperate with one another to radially support one another.

Referring now to <FIG>, a process of assembling the coupling <NUM> is shown at <NUM>. The tool <NUM> is engaged inside the female coupler <NUM> to radially support the tool <NUM> relative to the female coupler <NUM> at <NUM>. The segments <NUM> are inserted between the peripheral wall <NUM> of the female coupler <NUM> and the tool <NUM> at <NUM>. As shown, the tool radially supports the inner ends <NUM> of the segments <NUM>. The tool <NUM> is removed and the male coupler <NUM> is engaged to the segments <NUM> at <NUM>.

In the embodiment shown, the engaging of the tool at <NUM> includes inserting the fore section <NUM> of the tool <NUM> inside the bore of the female coupler <NUM>. In the present case, this bore is defined by the anti-rotation nut <NUM> of the female coupler <NUM>. As illustrated in <FIG>, the inserting of the segments <NUM> between the peripheral wall <NUM> of the female coupler <NUM> and the tool <NUM> at <NUM> includes inserting the segments <NUM> between the peripheral wall <NUM> and the tool <NUM> having the diameter D2 greater than the diameter D1 of the peripheral wall <NUM> of the female coupler <NUM> minus two times a length of the segments <NUM> defined between the inner ends <NUM> and the outer ends <NUM> of the segments <NUM>. In some cases, the inserting of the segments at <NUM> may include angling the segments <NUM> such that the segments <NUM> are non-parallel relative to a radial direction relative to a rotation axis of the coupling <NUM>, which corresponds here to the central axis <NUM> of the gas turbine engine <NUM>. The inserting of the segments <NUM> at <NUM> may include sliding the inner ends <NUM> of the segments <NUM> into the sockets or connections 73B defined by the tool <NUM>. Alternatively, the inner ends <NUM> of the segments <NUM> may be abutted against a cylindrical face of the tool. However, inserting the inner ends <NUM> of the segments <NUM> in the sockets that have shapes substantially matching a shape of the connections of the male coupler <NUM> may facilitate the assembly of the male coupler <NUM> at <NUM>.

The tool <NUM> may be rotated about the rotation axis until a first segment of the segments <NUM> is receivable within the connections 35A of the female coupler <NUM> and within a first socket or connection 73B of the connections 73B of the tool <NUM>. The tool <NUM> may be rotated after the tool <NUM> is engaged inside the female coupler <NUM>.

As depicted in <FIG> and <FIG>, the inserting of the segments <NUM> includes inserting the first tabs <NUM> of the segments <NUM> within gaps defined between the peripheral wall <NUM> of the female coupler <NUM> and the first retaining ring <NUM>.

Claim 1:
A tool (<NUM>) for installing segments (<NUM>) of a coupling (<NUM>) having couplers (<NUM>, <NUM>) drivingly engaged to one another by the segments (<NUM>), the tool (<NUM>) comprising:
a coupler-engaging section (<NUM>) engageable to a female coupler (<NUM>) of the couplers (<NUM>, <NUM>) for radially supporting the tool (<NUM>) relative to the female coupler (<NUM>) about a rotation axis (<NUM>) of the coupling (<NUM>), wherein the coupler-engaging section (<NUM>) defines a cylindrical member receivable within a central bore (61D) of the female coupler (<NUM>),
characterised in that the tool further comprises:
a peripheral wall (73A) secured to the coupler-engaging section (<NUM>) and extending circumferentially around the rotation axis (<NUM>), a diameter (D2) of the peripheral wall (73A) selected to allow insertion of the segments (<NUM>) between the female coupler (<NUM>) and the peripheral wall (73A), the peripheral wall (73A) defining an abutting surface against which radially inner ends (<NUM>) of the segments (<NUM>) abut during insertion of the segments (<NUM>) between the female coupler (<NUM>) and the peripheral wall (73A), wherein the peripheral wall (73A) of the tool (<NUM>) defines a plurality of sockets (73B) distributed circumferentially around the rotation axis (<NUM>), the plurality of sockets (73B) sized to accept the radially inner ends (<NUM>) of the segments (<NUM>).