Propulsion unit with longitudinal locking of at least one nacelle cover

Abstract

Propulsion assembly with longitudinal locking of at least one nacelle cowl Propulsion assembly (1) for aircraft comprising: a turbomachine; a nacelle (5) having a section provided with at least one cowl (7) mounted movably so as to be deployed between a working position and a maintenance position in order to provide access to a turbomachine (3); a pylon (11) adapted to fix the turbomachine and / or the nacelle (5) to the aircraft; a longitudinal locking mechanism (19) comprising, for each cowl (7), a finger (21) and a sheath (23) provided with two holding portions extending transversely to the corresponding longitudinal axis (17), the finger (21) being configured to be guided between the two holding portions in the maintenance position; the sheath (23) being attached to the corresponding cowl (7) or a connecting element to the corresponding cowl (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 cowl Field of invention

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

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

[0003] Typically, the two half-shells may be part of a thrust reverser. Also, each half-shell is mounted to be movable so as to be deployed between a working position and a maintenance position in order to provide access to the turbomachine.

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

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

[0006] The constraints of use of the half-shells can induce an offset of the half-shells relative to the rest of the nacelle along the longitudinal axis when changing positions between the working position and the maintenance position.

[0007] However, this longitudinal offset must be avoided because the half-shells risk not returning to their correct positioning when closing. This offset can thus lead to negative consequences such as mechanical deterioration at the points of contact with the rest of the nacelle and the movement of the half-shells in flight.

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

[0010] Also, there is a need for adjustment of the relative positions of the means of blocking and additional blocking means on their supports to ensure their good cooperation.

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

[0012] To this end, the present invention relates to a propulsion unit for aircraft comprising:

[0013] a nacelle having a section provided with at least one cover mounted to move so as to be deployed 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 to fix 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 along 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 sheath provided with two holding portions extending transversely to the corresponding longitudinal axis, the finger being configured to be guided between the two holding portions in the maintenance position; the finger and the sheath 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 sheath 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 covers. Due to their respective locations, secured to the covers on the one hand and secured to the pylon on the other hand, the fingers and sleeves of the longitudinal locking mechanism allow a large 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 arc of a circle 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 sheath is a projecting element attached to the cover or the corresponding connecting element.

[0019] This arrangement allows the cowl to be axially recentered. When closed, the cowl re-engages with the corresponding parts of the nacelle and the turbomachine. Thus, there is no axial offset between the cowl, the rest of the nacelle and the turbine machine in working position after closing.

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

[0021] According to one aspect of the invention, each cowl is a half-shell of generally semi-cylindrical shape. Preferably, the cowls 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 aircraft.

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

[0023] This arrangement makes it possible to define the arc of the circle at a location more or less distant from the longitudinal axis. It is thus possible, by the size of the finger and the sheath, to define the maximum opening angle of the hoods in the maintenance position.

[0024] This maximum angle is thus 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 cover, the finger and the sheath 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 sheath fit into each other between an intermediate position and the maintenance position.

[0026] This arrangement makes it possible to define a first step of transition from the working position to the intermediate position in which the finger and the sheath do not cooperate, that is to say 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 sheath, it is thus possible to define the opening angle of the hood from which the finger and the sheath begin to cooperate.

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

[0029] According to one aspect of the invention, for each cowl, the finger has on either side, transversely to the longitudinal axis and relative to a direction of air flow in the propulsion assembly, an upstream cooperation face and a downstream cooperation face configured to cooperate with the sheath, 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 sheath in the event of an offset along the longitudinal axis.

[0030] The upstream engagement chamfer and / or the downstream engagement chamfer make it possible to compensate for an offset along the longitudinal axis of the hood during opening. Thus, in intermediate position, in the event of an offset, the upstream engagement chamfer or the downstream engagement chamfer cooperates with the sheath and the offset is reduced then eliminated by moving towards the maintenance position.

[0031] This arrangement therefore makes it possible to ensure that there is no offset along the longitudinal axis of the covers in the maintenance position. Furthermore, even if an offset appears before the intermediate position, the upstream engagement chamfer or the downstream engagement chamfer make it possible to ensure that the fingers fit properly into their respective sheaths and that the offset 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 sheath are at a distance from the longitudinal axis and describe a trajectory in an arc of a circle makes it possible to produce slightly pronounced downstream and upstream engagement chamfers. Friction is thus limited when moving from the intermediate position to the maintenance position.

[0034] According to one aspect of the invention, for each cover, the sheath 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 sheath is thus a simple part of design and easy to produce. The parallel surfaces can be planar and cooperate with parallel planar parts of the upstream cooperation face and the downstream cooperation face contiguous respectively to the upstream engagement chamfer and to the downstream engagement chamfer.

[0036] Alternatively to the two parallel surfaces, each sheath may comprise two rollers free to rotate along axes transverse to the direction of insertion of the finger between the rollers. This alternative makes it possible to reduce friction.

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

[0038] This arrangement facilitates the construction of the sheath which is simple due to its shape with two distant studs. Furthermore, the intermediate space corresponds to the width of the finger along the longitudinal axis, excluding functional clearances.

[0039] According to one aspect of the invention, each cover comprises a beam extending parallel to the corresponding longitudinal axis, the second hinge part being attached to the beam on the one hand and the sheath or finger being attached to the beam on the other hand 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. longitudinal, the latter being distant from the hinge along the corresponding longitudinal axis.

[0041] According to one aspect of the invention, the sheath 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 may be attached to the extension or connecting element by rivets. The sheath may also be manufactured as a single piece with the extension or with the connecting element.

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

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

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

[0046] This arrangement makes it possible to adjust the axial position of the finger and / or the sheath by shifting one or more grooves so as to allow good alignment of the finger and the sheath in the maintenance position.

[0047] According to one aspect of the invention, the wedging device comprises, alternatively or additionally, a plurality of interchangeable shims capable of being arranged on either side of a support for attaching the finger or the sheath to the corresponding pylon or hood, the interchangeable shims being configured to be arranged in variable quantity on either side of the attachment support so as to adjust the position of the finger or the sheath along the longitudinal axis.

[0048] For example, the attachment support may be the hood extension or the connecting element to the hood to fix the sheath, in particular in two places corresponding to the two studs.

[0049] According to one aspect of the invention, each cover 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 releasing opening angle of the cover.

[0050] This arrangement makes it possible to guide the hoods at the start of opening. Preferably, for each hood, the fingers and sheaths 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 inclined relative to the downstream stop so as to define a tip.

[0052] The constraints on the hood when opening are oriented downstream. The orthogonal downstream stop thus allows the alignment of the hood to be maintained between the working position and the release opening angle.

[0053] According to one possibility, the release opening angle 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 release 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 cowl, an additional locking guide provided with a channel arranged in a casing of the turbomachine or the corresponding cowl and an arm attached to the cowl or the casing configured to cooperate with the channel so as to prevent translation of the cowl along the corresponding longitudinal axis relative to the casing between a first opening angle of the cowl less than the release opening angle and a second opening angle greater than an intermediate angle of start of cooperation between the finger and the corresponding sheath.

[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 making it possible to hold the covers axially between the holding by the semi-circumferential tooth and the holding by the longitudinal locking mechanism.

[0058] Furthermore, an overlap exists between these three longitudinal locking means so as to prevent any longitudinal shifting.

[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 which is set out below with reference to the appended 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 sectional view of the longitudinal locking mechanism.

[0065] [Fig.4] is a schematic 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 sectional view of a wedging device of the mechanism of longitudinal lock.

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

[0069] [Fig.8] is a schematic 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 figures

[0072] In the detailed description which follows of the figures defined above, the same elements or the elements fulfilling identical functions may retain the same references so as to simplify the understanding of the invention.

[0073] As illustrated in Figures 1 to 4 and 8, a propulsion unit 1 for an aircraft comprises a turbomachine 3, a nacelle 5 having a section provided with two cowls 7 or half-shells of generally semi-cylindrical 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 cover 7 is mounted to be mobile so as to be deployed between a working position and a maintenance position in order to provide access to the turbomachine 3.

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

[0076] The propulsion assembly 1 comprises 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 comprises, for each cover 7, a first hinge part 13 configured to cooperate with a second hinge part 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.

[0078] The propulsion assembly 1 comprises 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.

[0079] The finger 21 and the sheath 23 are 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.

[0080] The sheath 23 is attached to the corresponding cover 7 or a connecting element 27 to the corresponding cover 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 sheath 23 are interchangeable while retaining the same operation. The finger 21 could be attached to the corresponding cover 7 or the corresponding connecting element 27 and the sheath 23 to the pylon 11.

[0082] For each cover 7, the finger 21 and the sheath 23 are configured to be distant of the longitudinal axis 17 between the working position and the maintenance position.

[0083] The finger 21 and the sheath 23 extend at least partly in a curved manner along the trajectory of the arc of a 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.

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

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

[0087] As illustrated in [Fig.5], 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.

[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 sheath 23 in the event of an offset along the longitudinal axis 17.

[0089] The upstream engagement chamfer 37 and the downstream engagement chamfer 39 make it possible to compensate for an offset along the longitudinal axis 17 of the corresponding cover 7 during opening. Thus, in the intermediate position, in the event of an offset, the upstream engagement chamfer 37 or downstream engagement chamfer 39 cooperate with the sleeve 23 and the offset is reduced and then eliminated by advancing towards the maintenance position.

[0090] This arrangement therefore makes it possible to ensure that there is no offset along the longitudinal axis 17 of the covers 7 in the maintenance position. Furthermore, even if an offset appears before the intermediate position, the upstream engagement chamfer 37 or the downstream engagement chamfer 39 make it possible to ensure that the fingers 21 fit properly into their respective sheaths 23 and that the offset is eliminated.

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

[0092] Furthermore, the fact that the finger 21 and the sheath 23 are at a distance from the longitudinal axis 17 and describe a trajectory in the form of an arc of a circle 25 makes it possible to produce slightly pronounced downstream 39 and upstream 37 engagement chamfers. Friction is thus limited when moving 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 may be planar and cooperate with parallel planar parts 43 of the upstream cooperation face 31 and of the downstream cooperation face 33 contiguous respectively with the upstream engagement chamfer 37 and with the downstream engagement chamfer 39.

[0095] Alternatively to the two parallel surfaces 41, each sheath 23 may comprise two rollers free to rotate along axes transverse to the direction of insertion of the finger 21 between the rollers.

[0096] As illustrated in Figures 1 to 5, 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 complementarity of shape.

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

[0098] Each 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 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.

[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 sheath 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 comprises, 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.

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

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

[0105] According to one possibility, illustrated in [Fig. 6], for each cover 7, the wedging device 53 comprises a grooved wedge 55 configured to be mounted on the pylon 11, the grooved wedge 55 having a plurality of grooves positioned normally to the longitudinal axis 17 so as to allow cooperation with the finger 21 or the sheath 23 according to a plurality of axially adjusted positions. [Fig. 6] is a side sectional view showing a rivet or screw type fixing 51.

[0106] This arrangement makes it possible to adjust the axial position of the finger 21 and / or the sheath 23 by shifting one or more grooves so as to allow good alignment of the finger 21 and the sheath 23 in the maintenance position.

[0107] As illustrated in [Fig.7], the wedging device 53 may also comprise a plurality of interchangeable shims 57 capable of being arranged on either side of a support for attaching the sheath 23 to the pylon 11 or the corresponding cover 7, the interchangeable shims 57 being configured to be arranged in variable quantity on either side of the attachment support so as to adjust the position of the sheath 23 along the longitudinal axis.

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

[0109] As illustrated in [Fig.8], each cover 7 has a semi-circumferential tooth 59 extending in a plane 61 transverse 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 7.

[0110] This arrangement makes it possible to guide the hoods 7 at the start of opening.

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

[0112] The stresses on the cover 7 when opening are oriented downstream. The orthogonal downstream stop 65 thus allows the alignment of the cover 7 to be maintained between the working position and the release opening angle.

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

[0114] According to another possibility, the release 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 comprise for each cowl 7, an additional locking guide, not shown here, provided with a channel arranged in a casing of the turbomachine 3 or 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 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.

[0116] Each cover 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 making it possible to hold the covers 7 axially between the holding by the semi-circumferential tooth 59 and the holding by the longitudinal locking mechanism 19.

[0118] Furthermore, an overlap exists between these three longitudinal locking means so as to prevent any longitudinal shifting.

[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, secured to the covers 7 on the one hand and secured 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 cover 7 and the pylon 11 can be defined by the radius of the arc of a circle 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 makes it possible to define the arc of a circle 25 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 sheath 23, to define the maximum opening angle of the covers 7 in the maintenance position.

[0123] This maximum angle is thus greater than what can be obtained 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 goes without saying, the invention is not limited to the single embodiment described above as an example; on the contrary, it encompasses all variant embodiments.

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 be deployed 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, in which 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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