Propulsion system with longitudinal locking of at least one nacelle cowling

Abstract

Propulsion assembly with longitudinal locking of at least one nacelle cowling. Propulsion assembly (1) for an aircraft comprising: a turbomachine; a nacelle (5) having a cross-section provided with at least one cowling (7) mounted movably so as to deploy between a working position and a maintenance position in order to provide access to a turbomachine (3); a pylon (11) adapted for attaching the turbomachine and / or the nacelle (5) to the aircraft; a longitudinal locking mechanism (19) comprising, for each cowling (7), a finger (21) and a sleeve (23) having two retaining portions extending transversely to the corresponding longitudinal axis (17), the finger (21) being configured to be guided between the two retaining portions in the maintenance position; the sleeve (23) being attached to the corresponding cowling (7) or a connecting element to the corresponding cowling (7) and the finger (21) being attached to the pylon (11), or vice versa. Figure 1

Description

Title of the invention: Propulsion assembly with longitudinal locking of at least one nacelle hood Scope of the invention

[0001] The present invention relates to a propulsion assembly comprising a longitudinal locking mechanism for at least one nacelle hood. Previous art

[0002] It is known to have a propulsion assembly comprising a nacelle with a section provided with two half-shells of generally hemicylindrical shape on either side of a longitudinal plane of symmetry of the nacelle, said plane being generally vertical.

[0003] Typically, the two half-shells can form part of a thrust reverser. Also, each half-shell is mounted movably so as to deploy between a working position and a maintenance position in order to provide access to the turbine.

[0004] The working position corresponds to the closed position adopted in flight. The maintenance position corresponds to an open position that allows access to the turbomachine or turbojet engine from outside the nacelle.

[0005] Each half-shell is mounted pivotally about a corresponding longitudinal axis extending in the upper part of the nacelle, i.e. at a clock position close to 12 o'clock.

[0006] The constraints of use of the half-shells may induce a displacement of the half-shells relative to the rest of the nacelle along the longitudinal axis during changes of position between working position and maintenance position.

[0007] However, this longitudinal offset must be avoided because the half-shells may not return to their correct position during closure. This offset can therefore lead to negative consequences such as mechanical damage at the points of contact with the rest of the nacelle and displacement of the half-shells in flight.

[0008] Document FR 2 920 141 A1 proposes locking means to prevent this longitudinal misalignment. Each half-shell comprises locking means that cooperate in the maintenance position with complementary locking means arranged on a fixed frame of the turbomachine. This solution is satisfactory in that the misalignment is avoided by maintaining alignment in the maintenance position.

[0009] However, the proposed solution limits the opening angle between the working position and the maintenance position due to the bulkiness of the locking means.

[0010] Also, there is a need to adjust the relative positions of the means of blocking and additional blocking measures on their platforms to ensure their proper cooperation.

[0011] The present invention aims to resolve all or part of the disadvantages mentioned above. Description of the invention

[0012] To this end, the present invention relates to an aircraft propulsion system comprising:

[0013] a nacelle having a section provided with at least one movable hood so as to deploy between a working position and a maintenance position in order to provide access to a turbomachine intended to be mounted in the nacelle,

[0014] a pylon adapted for fixing the turbomachine and / or the nacelle to the aircraft; the pylon comprising, for each cowl, a first hinge part configured to cooperate with a second hinge part of the corresponding cowl so as to allow the pivoting of said cowl about a corresponding longitudinal axis between the working position and the maintenance position,

[0015] a longitudinal locking mechanism comprising, for each hood, a finger and a sleeve having two retaining portions extending transversely to the corresponding longitudinal axis, the finger being configured to be guided between the two retaining portions in the maintenance position; the finger and the sleeve being configured to describe a relative trajectory along an arc of a circle around the corresponding longitudinal axis between the working position and the maintenance position; the sleeve being attached to the corresponding hood or a connecting element to the corresponding hood and the finger being attached to the pylon, or vice versa.

[0016] According to one aspect of the invention, the propulsion assembly comprises two hoods. Due to their respective locations, attached to the hoods on the one hand and attached to the pylon on the other, the fingers and sleeves of the longitudinal locking mechanism allow a significant opening angle between the working position and the maintenance position.

[0017] Indeed, the length of the stroke between a hood and the pylon can be defined by the radius of the circular arc described by the stroke. It is therefore easy to increase the angle between the working position and the maintenance position while taking advantage of the longitudinal locking.

[0018] According to one aspect of the invention, the sleeve is a protruding element attached to the hood or the corresponding connecting element.

[0019] This arrangement allows the hood to be axially recentered. During closing, the hood re-engages with the corresponding parts of the nacelle and the turbomachine. Thus, there is no axial misalignment between the hood, the rest of the nacelle, and the turbomachine. Bomachine in working position after closing.

[0020] Preferably, the propulsion assembly includes the turbomachine.

[0021] According to one aspect of the invention, each cowling is a half-shell of generally hemispherical shape. Preferably, the cowlings extend on either side of a longitudinal plane of symmetry of the nacelle. In particular, this plane is vertical. Alternatively, this plane may be horizontal, for example, for business jets.

[0022] According to one aspect of the invention, for each hood, the finger and the sleeve are configured to be spaced apart from the longitudinal axis between the working position and the maintenance position.

[0023] This arrangement allows the arc of the circle to be defined at a location more or less distant from the longitudinal axis. It is thus possible, by adjusting the size of the finger and the sleeve, to define the maximum opening angle of the covers in the maintenance position.

[0024] This maximum angle is therefore greater than what can be obtained with a longitudinal locking mechanism located at the hinge, i.e. located at the longitudinal axis.

[0025] According to one aspect of the invention, for each hood, the finger and the sleeve extend at least partly in a curved manner along the trajectory of the arc of a circle around the longitudinal axis so that the finger and the sleeve interlock with each other between an intermediate position and the maintenance position.

[0026] This arrangement allows for the definition of a first step of transition from the working position to the intermediate position in which the finger and the sheath do not cooperate, i.e. are distant from each other, and a second step of cooperation between the intermediate position and the maintenance position.

[0027] By dimensioning and positioning the finger and the corresponding sleeve, it is thus possible to define the opening angle of the hood from which the finger and the sleeve begin to cooperate.

[0028] The finger can have a dimension greater or less than a quarter circle depending on the position of the sheath.

[0029] According to one aspect of the invention, for each hood, the finger has on either side, transverse to the longitudinal axis and relative to a direction of airflow in the propulsion assembly, an upstream cooperation face and a downstream cooperation face configured to cooperate with the sleeve, the upstream cooperation face and / or the downstream cooperation face respectively providing at one end of the finger an upstream engagement chamfer and / or a downstream engagement chamfer configured to engage the finger in the sleeve in case of misalignment along the longitudinal axis.

[0030] The upstream engagement chamfer and / or the downstream engagement chamfer compensate for any misalignment along the longitudinal axis of the hood during opening. Thus, in In the intermediate position, if there is a misalignment, the upstream engagement chamfer or the downstream engagement chamfer cooperates with the sleeve and the misalignment is reduced and then eliminated by moving towards the maintenance position.

[0031] This arrangement therefore ensures that there is no misalignment along the longitudinal axis of the covers in the maintenance position. Furthermore, even if a misalignment occurs before the intermediate position, the upstream or downstream engagement chamfer ensures that the fingers fit correctly into their respective sleeves and that the misalignment is eliminated.

[0032] Thus, when the hoods move back from the maintenance position to the working position, there is no offset along the longitudinal axis and the hoods return to their working positions.

[0033] Furthermore, the fact that the finger and the sleeve are at a distance from the longitudinal axis and describe an arc-shaped trajectory allows for the creation of shallow downstream and upstream engagement chamfers. Friction is thus limited during the transition from the intermediate position to the maintenance position.

[0034] According to one aspect of the invention, for each hood, the sleeve has two parallel surfaces extending transversely to the longitudinal axis, the two parallel surfaces being configured to cooperate respectively with the upstream cooperation face and the downstream cooperation face.

[0035] The sleeve is thus a simple part in design and easy to produce. The parallel surfaces can be flat and cooperate with parallel flat parts of the upstream cooperation face and the downstream cooperation face contiguous respectively to the upstream engagement chamfer and the downstream engagement chamfer.

[0036] Alternatively to two parallel surfaces, each sleeve may comprise two rollers free to rotate about axes transverse to the direction of insertion of the finger between the rollers. This alternative reduces friction.

[0037] According to one aspect of the invention, for each hood, the sheath comprises two distinct studs providing an intermediate space extending along the longitudinal axis and adapted to the introduction of the finger by complementary shape.

[0038] This arrangement facilitates the construction of the sheath, which is simple in shape with two widely spaced studs. Furthermore, the intermediate space corresponds to the width of the finger along the longitudinal axis, within the limits of functional clearances.

[0039] According to one aspect of the invention, each hood comprises a beam extending parallel to the corresponding longitudinal axis, the second hinge part being attached to the beam on one side and the sleeve or finger being attached to the beam on the other side so as to be distant from the second hinge part along the corresponding longitudinal axis.

[0040] This arrangement allows easier access to the Ion- locking mechanism gitudinal, the latter being distant from the hinge along the corresponding longitudinal axis.

[0041] According to one aspect of the invention, the sleeve or the finger is attached to an extension of the corresponding beam or to the connecting element itself attached to the beam.

[0042] The sheath or finger can be attached to the extension or connecting element by rivets. The sheath can also be manufactured as a single piece attached to the extension or connecting element.

[0043] According to one aspect of the invention, the propulsion assembly further comprises, for each hood, a shimming device configured to be inserted between the finger and the pylon and / or between the sleeve and the corresponding hood, or vice versa; the shimming device being configured to adjust the position of the finger and / or the sleeve along the longitudinal axis.

[0044] It is thus possible to move the finger or the sleeve along the longitudinal axis so as to align them according to the existing operating clearances between the tur-bomachine, the nacelle and the hood.

[0045] According to one aspect of the invention, for each hood, the shimming device comprises a grooved shim configured to be mounted on the corresponding pylon or hood, the grooved shim having a plurality of grooves positioned normally to the longitudinal axis so as to allow cooperation with the finger or sleeve according to a plurality of axially adjusted positions.

[0046] This arrangement allows the axial position of the finger and / or the sleeve to be adjusted by shifting one or more grooves so as to allow good alignment of the finger and the sleeve in the maintenance position.

[0047] According to one aspect of the invention, the shimming device comprises, alternatively or in addition, a plurality of interchangeable shims suitable for being arranged on either side of a finger or sleeve attachment support on the corresponding pylon or hood, the interchangeable shims being configured to be arranged in variable quantities on either side of the attachment support so as to adjust the position of the finger or sleeve along the longitudinal axis.

[0048] By way of example, the attachment support may be the hood extension or the hood connection element for fixing the sleeve, in particular in two places corresponding to the two studs.

[0049] According to one aspect of the invention, each hood has a semi-circumferential tooth extending in a plane transverse to the corresponding longitudinal axis, the semi-circumferential tooth being configured to cooperate with a corresponding groove of the turbomachine in the working position and up to a liberating opening angle of the hood.

[0050] This arrangement allows the hoods to be guided at the beginning of the opening. Preferably, for each hood, the fingers and sleeves do not cooperate in the working position.

[0051] According to one aspect, the semi-circumferential tooth has a downstream stop extending substantially orthogonally to the corresponding longitudinal axis and an upstream stop extending inclinedly relative to the downstream stop so as to define a point.

[0052] The stresses on the hood during opening are directed downstream. The orthogonal downstream stop thus maintains the alignment of the hood between the working position and the release opening angle.

[0053] According to one possibility, the opening angle for release is less than the angle of the hood in the intermediate position. In this case, the hood is free of constraint between these two opening angles.

[0054] According to another possibility, the opening angle is greater than the angle of the hood in the intermediate position. In this second case, the hood is doubly constrained between these two opening angles. This overlap prevents any movement of the hood along the longitudinal axis.

[0055] According to one aspect of the invention, the propulsion assembly comprises, for each hood, an additional blocking guide provided with a channel formed in a housing of the tur-bomachine or the corresponding hood and an arm attached to the hood or the housing configured to cooperate with the channel so as to prevent a translation of the hood along the corresponding longitudinal axis relative to the housing between a first opening angle of the hood less than the opening angle of release and a second opening angle greater than an intermediate angle of start of cooperation between the finger and the corresponding sleeve.

[0056] Each hood is first held by the semi-circumferential tooth, then by the locking guide and finally by the longitudinal locking mechanism.

[0057] The additional locking guide is thus an axial locking element allowing the hoods to be held axially between the holding by the semi-circumferential tooth and the holding by the longitudinal locking mechanism.

[0058] Furthermore, there is an overlap between these three means of longitudinal blocking so as to prevent any longitudinal shift.

[0059] According to one aspect of the invention, the longitudinal locking mechanism comes into operation for an opening angle of the hood relative to the longitudinal axis of approximately 10°.

[0060] The different aspects defined above, which are not incompatible, can be combined. Brief description of the figures

[0061] The invention will be better understood with the aid of the detailed description set out below in relation to the accompanying drawings.

[0062] [Fig-1] is a detailed perspective view of an aircraft propulsion assembly comprising a longitudinal locking mechanism.

[0063] [Fig.2] is a perspective view of the longitudinal locking mechanism.

[0064] [Fig.3] is a schematic cross-sectional view of the longitudinal locking mechanism.

[0065] [Fig.4] is a schematic cross-sectional view of a variant of the locking mechanism longitudinal.

[0066] [Fig.5] is a top view of the longitudinal locking mechanism.

[0067] [Fig.6] is a schematic cross-sectional view of a mechanism's stabilization device longitudinal blockage.

[0068] [Fig.7] is a schematic cross-sectional view of a variant of the stabilization device of the longitudinal locking mechanism.

[0069] [Fig.8] is a schematic cross-sectional view of the propulsion assembly.

[0070] [Fig.9] is a perspective view of the propulsion assembly in working position.

[0071] [Fig. 10] is a perspective view of the propulsion assembly in the maintenance position. Description with reference to the figures

[0072] In the detailed description that will follow of the figures defined above, the same elements or elements fulfilling identical functions may retain the same references in order to simplify the understanding of the invention.

[0073] As illustrated in figures 1 to 4 and 8, a propulsion assembly 1 for an aircraft comprises a turbomachine 3, a nacelle 5 having a section provided with two cowls 7 or half-shells of generally hemicylindrical shape on either side of a longitudinal vertical plane of symmetry 9 of the nacelle 5.

[0074] As illustrated in figures 9 and 10, each hood 7 is mounted movable so as to deploy between a working position and a maintenance position in order to provide access to the turbomachine 3.

[0075] Although a propulsion assembly 1 with a shrouded turbomachine 3 is illustrated, the invention would be applicable to a propulsion assembly 1 with an unshrouded turbomachine 3.

[0076] The propulsion assembly 1 includes a pylon 11 adapted to fix the turbomachine 3 and / or the nacelle 5 to a wing and / or to a fuselage of the aircraft.

[0077] The pylon 11 includes, for each hood 7, a first hinge part 13 configured to cooperate with a second hinge part 15 of the corresponding hood 7 so as to allow the pivoting of said hood 7 along a corresponding longitudinal axis 17 between the working position and the maintenance position.

[0078] The propulsion assembly 1 includes a longitudinal locking mechanism 19 comprising, for each hood 7, a finger 21 and a sleeve 23 having two retaining portions 24 extending transversely to the corresponding longitudinal axis 17, the finger 21 being configured to be guided between the two holding portions 24 in the maintenance position.

[0079] The finger 21 and the sleeve 23 are configured to describe a relative trajectory along a circular arc 25 around the corresponding longitudinal axis 17 between the working position and the maintenance position.

[0080] The sleeve 23 is attached to the corresponding hood 7 or a connecting element 27 to the corresponding hood 7 and the finger 21 is attached to the pylon 11. Figures 3, 4 and 7 show the connecting element 27 while these elements have not been shown in the other figures to simplify the views.

[0081] Furthermore, the finger 21 and the sleeve 23 are interchangeable while maintaining the same function. The finger 21 could be attached to the corresponding cover 7 or the corresponding connecting element 27, and the sleeve 23 to the pylon 11.

[0082] For each hood 7, the finger 21 and the sleeve 23 are configured to be spaced apart of the longitudinal axis 17 between the working position and the maintenance position.

[0083] The finger 21 and the sleeve 23 extend at least partly in a curved manner along the path of the arc of the circle 25 around the longitudinal axis 17 so that the finger 21 and the sleeve 23 interlock with each other between an intermediate position and the maintenance position.

[0084] This defines a first step of transition from the working position to the intermediate position in which the finger 21 and the sheath 23 do not cooperate and a second step of cooperation between the intermediate position and the maintenance position.

[0085] By dimensioning and positioning the finger 21 and the corresponding sleeve 23, it is thus possible to define the opening angle of the hood from which the finger 21 and the sleeve 23 begin to cooperate.

[0086] As illustrated in figures 3 and 4 which represent variant embodiments, the finger 21 can have a dimension greater or less than a quarter circle depending on the position of the sheath 23.

[0087] As illustrated in [Fig.5], the finger 21 has on either side, transverse to the longitudinal axis 17 and relative to a direction of airflow 29 in the propulsion assembly 1, an upstream cooperation face 31 and a downstream cooperation face 33 configured to cooperate with the sleeve 23.

[0088] The upstream cooperation face 31 and the downstream cooperation face 33 respectively provide at one end of the finger 21 an upstream engagement chamfer 37 and a downstream engagement chamfer 39 configured to engage the finger 21 in the sleeve 23 in case of misalignment along the longitudinal axis 17.

[0089] The upstream engagement chamfer 37 and the downstream engagement chamfer 39 allow for compensation of a misalignment along the longitudinal axis 17 of the corresponding hood 7 during opening. Thus, in the intermediate position, in the event of a misalignment, the upstream engagement chamfer 37 or downstream engagement chamfer 39 cooperate with sleeve 23 and the offset is reduced and then eliminated by moving towards the maintenance position.

[0090] This arrangement therefore ensures that there is no misalignment along the longitudinal axis 17 of the covers 7 in the maintenance position. Furthermore, even if a misalignment appears before the intermediate position, the upstream engagement chamfer 37 or the downstream engagement chamfer 39 ensures that the fingers 21 fit correctly into their respective sleeves 23 and that the misalignment is eliminated.

[0091] Thus, when the hoods 7 move again from the maintenance position to the working position, there is no offset along the longitudinal axis 17 and the hoods 7 correctly return to their working positions.

[0092] Furthermore, the fact that the finger 21 and the sleeve 23 are at a distance from the longitudinal axis 17 and describe a circular arc 25 trajectory allows for the creation of shallow downstream 39 and upstream 37 engagement chamfers. Friction is thus limited during the transition from the intermediate position to the maintenance position.

[0093] The sheath 23 has two parallel surfaces 41 extending transversely to the longitudinal axis 17, the two parallel surfaces 41 being configured to cooperate respectively with the upstream cooperation face 31 and the downstream cooperation face 33.

[0094] The parallel surfaces 41 can be planar and cooperate with parallel planar parts 43 of the upstream cooperation face 31 and the downstream cooperation face 33 contiguous respectively to the upstream engagement chamfer 37 and the downstream engagement chamfer 39.

[0095] Alternatively to the two parallel surfaces 41, each sleeve 23 may include two rollers free to rotate about axes transverse to the direction of introduction of the finger 21 between the rollers.

[0096] As illustrated in figures 1 to 5, the sheath 23 comprises two distinct studs 45 providing an intermediate space 47 extending along the longitudinal axis 17 and adapted to the introduction of the finger 21 by complementary shape.

[0097] The intermediate space 47 corresponds to the width of the finger 21 along the longitudinal axis 17 within functional clearances.

[0098] Each hood 7 includes a beam 49 extending parallel to the corresponding longitudinal axis 17, the second hinge part 15 being attached to the beam 49 on one side and the sleeve 23 being attached to the beam 49 on the other side so as to be distant from the second hinge part 15 along the corresponding longitudinal axis 17.

[0099] This arrangement allows easier access to the longitudinal locking mechanism 19, the latter being distant from the hinge along the corresponding longitudinal axis 17.

[0100] The sleeve 23 is attached to an extension of the corresponding beam 49 or to the connecting element 27, itself attached to the beam 49.

[0101] The sheath 23 can be fixed to the extension or to the connecting element 27 by rivets or screws 51. The sheath 23 can also be manufactured as a single piece with the extension or with the connecting element 27.

[0102] As illustrated in figures 6 and 7, the propulsion assembly 1 further includes, for each hood 7, a shim 53 configured to be inserted between the finger 21 and the pylon 11 and / or between the sleeve 23 and the corresponding hood 7.

[0103] The shimming device 53 is configured to adjust the position of the finger 21 or the sleeve 23 along the longitudinal axis 17.

[0104] It is thus possible to move the finger 21 or the sleeve 23 along the longitudinal axis 17 so as to align them according to the existing operating clearances between the turbomachine 3, the nacelle 5 and the hood 7.

[0105] According to one possibility, illustrated in [Fig. 6], for each hood 7, the shim 53 comprises a grooved shim 55 configured to be mounted on the pylon 11, the grooved shim 55 having a plurality of grooves positioned perpendicular to the longitudinal axis 17 so as to allow cooperation with the finger 21 or the sleeve 23 in a plurality of axially adjusted positions. [Fig. 6] is a side cross-sectional view showing a rivet or screw-type fastener 51.

[0106] This arrangement allows the axial position of the finger 21 and / or the sleeve 23 to be adjusted by shifting one or more grooves so as to allow good alignment of the finger 21 and the sleeve 23 in the maintenance position.

[0107] As illustrated in [Fig.7], the shim device 53 can also include a plurality of interchangeable shims 57 suitable for being arranged on either side of a support for attaching the sleeve 23 to the pylon 11 or the corresponding hood 7, the interchangeable shims 57 being configured to be arranged in variable quantities on either side of the support for attaching so as to adjust the position of the sleeve 23 along the longitudinal axis.

[0108] By way of example, the attachment support may be the extension of the hood 7 or the connecting element 27 to the hood 7 for fixing the sleeve 23, in particular in two places corresponding to the two studs 45.

[0109] As illustrated in [Fig.8], each hood 7 has a semi-circumferential tooth 59 extending in a transverse plane 61 to the corresponding longitudinal axis 17, the semi-circumferential tooth 59 being configured to cooperate with a corresponding groove 63 of the turbomachine 3 in the working position and up to a liberating opening angle of the hood 7.

[0110] This arrangement allows the hoods 7 to be guided at the beginning of the opening.

[0111] The semi-circumferential tooth 59 has a distal stop 65 extending substantially orthogonally to the corresponding longitudinal axis 17 and an upstream stop 67 extending in an inclined manner with respect to the downstream stop 65 so as to define a point.

[0112] The constraints on the hood 7 during opening are directed downstream. The orthogonal downstream stop 65 thus maintains the alignment of the hood 7 between the working position and the release opening angle.

[0113] According to one possibility, the opening angle for release is less than the angle of the cover 7 in the intermediate position. In this case, the cover 7 is free of constraint between these two opening angles.

[0114] According to another possibility, the opening angle is greater than the angle of the hood in the intermediate position. In this second case, the hood 7 is doubly constrained between these two opening angles. This overlap prevents any movement of the hood 7 along the longitudinal axis 17.

[0115] The propulsion assembly 1 may also include for each hood 7, an additional blocking guide, not shown here, provided with a channel formed in a housing of the turbomachine 3 or the corresponding hood 7 and an arm attached to the hood 7 or the housing configured to cooperate with the channel so as to prevent a translation of the hood along the corresponding longitudinal axis 17 relative to the housing between a first opening angle of the hood 7 less than the opening angle of release and a second opening angle greater than an intermediate angle of start of cooperation between the finger 21 and the corresponding sleeve 23.

[0116] Each hood 7 is first held by the semi-circumferential tooth 59, then by the locking guide and finally by the longitudinal locking mechanism 19.

[0117] The additional locking guide is thus an axial locking element allowing the hoods 7 to be held axially between the holding by the semi-circumferential tooth 59 and the holding by the longitudinal locking mechanism 19.

[0118] Moreover, there is an overlap between these three means of longitudinal blocking so as to prevent any longitudinal shift.

[0119] The longitudinal locking mechanism 19 comes into operation for an opening angle of the hood 7 relative to the longitudinal axis of approximately 10°.

[0120] It thus appears that, due to their respective locations, attached to the hoods 7 on the one hand and attached to the pylon 11 on the other hand, the fingers 21 and sleeves 23 of the longitudinal locking mechanism 19 allow a significant opening angle between the working position and the maintenance position.

[0121] Indeed, the length of the stroke between a hood 7 and the pylon 11 can be defined by the radius of the circular arc 25 described by the stroke. It is therefore easy to increase the angle between the working position and the maintenance position while taking advantage of the longitudinal locking.

[0122] This arrangement allows the arc of the circle 25 to be defined at a location more or less distant from the longitudinal axis 17. It is thus possible, by the size of the finger 21 and the sleeve 23, to define the maximum opening angle of the hoods 7 in the maintenance position.

[0123] This maximum angle is therefore greater than what is possible to obtain with a longitudinal locking mechanism located at the hinge, i.e., located at the longitudinal axis. This makes the longitudinal locking mechanism described here particularly advantageous.

[0124] As can be understood, the invention is not limited to the single embodiment described above by way of example, but on the contrary encompasses all variants of its realization.

Claims

Claims

1. Propulsion assembly (1) for aircraft comprising: - a nacelle (5) having a section provided with at least one cover (7) mounted to move so as to deploy between a working position and a maintenance position in order to provide access to a turbomachine (3) intended to be mounted in the nacelle (5), - a pylon (11) adapted to fix the turbomachine (3) and / or the nacelle (5) to the aircraft;the pylon (11) comprising, for each cover (7), a first hinge portion (13) configured to cooperate with a second hinge portion (15) of the corresponding cover (7) so as to allow the pivoting of said cover (7) along a corresponding longitudinal axis (17) between the working position and the maintenance position, - a longitudinal locking mechanism (19) comprising, for each cover (7), a finger (21) and a sheath (23) provided with two holding portions (24) extending transversely to the corresponding longitudinal axis (17), the finger (21) being configured to be guided between the two holding portions (24) in the maintenance position; the finger (21) and the sheath (23) being configured to describe a relative trajectory along an arc of a circle (25) around the corresponding longitudinal axis (17) between the working position and the maintenance position;the sheath (23) being attached to the corresponding cover (7) or a connecting element (27) to the corresponding cover (7) and the finger (21) being attached to the pylon (11), or vice versa.;

2. Propulsion assembly (1) according to claim 1, in which, for each cover (7), the finger (21) and the sheath (23) are configured to be distant from the longitudinal axis (17) between the working position and the maintenance position.

3. Propulsion assembly (1) according to one of claims 1 or 2, in which, for each cover (7), the finger (21) and the sheath (23) extend at least partly in a curved manner along the trajectory of the arc of circle (25) around the longitudinal axis (17) so that the finger (21) and the sheath (23) fit into each other between an intermediate position and the maintenance position.

4. Propulsion assembly (1) according to one of claims 1 to 3, wherein for each cover (7), the finger (21) has on either side, transversely to the longitudinal axis (17) and relative to a direction of air flow (29) in the propulsion assembly (1), an upstream cooperation face (31) and a downstream cooperation face (33) configured to cooperate with the sheath (23), the upstream cooperation face (31) and / or the downstream cooperation face (33) respectively forming at one end of the finger (21) an upstream engagement chamfer (37) and / or a downstream engagement chamfer (39) configured to engage the finger (21) in the sheath (23) in the event of an offset along the longitudinal axis (17).

5. Propulsion assembly (1) according to claim 4, in which, for each cover (7), the sheath (23) has two parallel surfaces (41) extending transversely to the longitudinal axis (17), the two parallel surfaces (41) being configured to cooperate respectively with the upstream cooperation face (31) and the downstream cooperation face (33).

6. Propulsion assembly (1) according to one of claims 1 to 5, in which, for each cover (7), the sheath (23) comprises two separate studs (45) providing an intermediate space (47) extending along the longitudinal axis (17) and being adapted for the introduction of the finger (21) by complementary shape.

7. Propulsion assembly (1) according to one of claims 1 to 6, in which the at least one cover (7) comprises a beam (49) extending parallel to the corresponding longitudinal axis (17), the second hinge part (15) being attached to the beam (49) on the one hand and the sheath (23) or the finger (21) being attached to the beam (49) on the other hand so as to be distant from the second hinge part (15) along the corresponding longitudinal axis (17).

8. Propulsion assembly (1) according to one of claims 1 to 7, further comprising, for each cover (7), a wedging device (53) configured to be inserted between the finger (21) and the pylon (11) and / or between the sheath (23) and the corresponding cover (7), or vice versa; the wedging device (53) being configured to adjust the position of the finger (21) and / or of the sheath (23) along the longitudinal axis (17).

9. Propulsion assembly (1) according to one of claims 1 to 8, in which the at least one cover (7) has a semi-circumferential tooth (59) extending in a plane transverse (61) to the corresponding longitudinal axis (17), the semi-circumferential tooth (59) being configured to cooperate with a corresponding groove (63) of the turbomachine (3) in the working position and up to a releasing opening angle of the cover.

10. Propulsion assembly (1) according to claim 9, comprising, for each cowl (7), an additional locking guide provided with a channel arranged in a casing of the turbomachine (3) or of the corresponding cowl (7) and an arm attached to the cowl (7) or the casing configured to cooperate with the channel so as to prevent a translation of the cowl (7) along the corresponding longitudinal axis (17) relative to the casing between a first opening angle of the cowl (7) less than the release opening angle and a second opening angle greater than an intermediate angle of start of cooperation between the finger (21) and the corresponding sheath (23).

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