DEVICE FOR ATTACHING A CONNECTING ROD SMALL END FOR A THRUST REVERSAL CASCADE FLAP

Abstract

A device for attaching a connecting rod small end for a thrust reversal cascade flap onto a fixed internal structure of a turbojet engine nacelle includes a fitting configured to be fixed to the internal structure and a connection interface forming a joint between the connecting rod small end and the fitting. The device further includes a removable fork configured to cooperate with the connection interface, wherein the fork and the connection interface are arranged inside the fitting.

Claims

1. A device for attaching a connecting rod small end of a thrust reversal cascade flap onto an inner fixed structure of a turbojet engine nacelle, comprising a fitting configured to be fixed to said inner fixed structure and a connection interface forming a joint between the connecting rod small end and the fitting, and a removable locking means configured to cooperate with the connection interface so as to rotationally lock the connection means, the locking means and the connection interface being arranged inside the fitting.

2. The device according to claim 1, wherein the connection interface comprises a first screw and a first nut configured to cooperate with said first screw.

3. The device according to claim 2, wherein the first screw comprises at least one flat surface or at least one shoulder in contact with a base, the removable locking means comprising a fork including at least one tooth extending along a transverse axis perpendicular to a longitudinal axis of the first screw, said at least one tooth cooperating with said at least one flat surface or shoulder.

4. The device according to claim 2, wherein the first screw comprises at least one housing extending perpendicularly to a longitudinal axis of the first screw, and wherein the removable locking means includes a fork comprising a rod configured to be inserted into said housing.

5. The device according to claim 1, further comprising holding means arranged inside the fitting and configured to hold the locking means in position.

6. The device according to claim 5, wherein the holding means comprise a spring pin surrounding a support area integral with the fitting and passing through the locking means.

7. The device according to claim 5, wherein the holding means comprise at least one rivet located on the locking means.

8. The device according to claim 5, wherein the holding means comprise a second screw configured to cooperate with a second nut.

9. The device according to claim 8, wherein the holding means comprise a lockwire arranged between the second nut and the locking means, configured to hold the second screw in position.

10. The device according to claim 5, wherein the holding means are at a distance comprised between 12 mm and 200 mm from the connection interface.

11. The device according to claim 1, wherein the connecting rod small end comprises at least two projections perpendicular to the longitudinal axis of the connecting rod and in contact with the locking means.

12. A cascade thrust reverser comprising the device according to claim 1.

13. A nacelle for an aircraft turbojet engine, including the cascade thrust reverser according to claim 12.

Description

[0048] Other purposes, features and advantages of the invention will appear upon reading the following description, given only by way of non-limiting example, and made with reference to the indexed drawings on which:

[0049] FIG. 1 schematically shows a turbojet engine nacelle for an aircraft comprising a cascade thrust reverser according to the prior the art;

[0050] FIG. 2A

[0051] FIG. 2B each illustrate a view according to an axial section of a cascade thrust reverser respectively in direct jet and reverse jet position according to the prior art;

[0052] FIG. 3A

[0053] FIG. 3B schematically illustrate a first embodiment of a device for attaching a connecting rod small end for a thrust reversal cascade flap;

[0054] FIG. 4 illustrates a second embodiment of said attachment device;

[0055] FIG. 5A

[0056] FIG. 5B show perspective views of a third embodiment of the device for attaching the connecting rod small end;

[0057] FIG. 6

[0058] FIG. 7 illustrate examples of means for holding a removable fork arranged inside said fixing device in accordance with the invention and,

[0059] FIG. 8A

[0060] FIG. 8B show an embodiment of the connecting rod small end and its arrangement in said device.

[0061] FIG. 1 shows a propulsion unit 1 comprising a nacelle 2 generally of tubular structure along a longitudinal axis X.

[0062] It further comprises a turbojet engine 3, for example of the bypass type, suitable for generating, via a rotating fan 4, a primary and secondary air flow.

[0063] The secondary air flow circulates outside the turbojet engine 3 through an annular flow path 5 formed between two walls of the nacelle 2.

[0064] The primary and secondary flow paths are ejected from the turbojet engine 3 by an ejection nozzle 6 located at the rear of the nacelle 2 and comprising more particularly a primary nozzle 61 capable of ejecting the primary flow path.

[0065] The ejection nozzle 6 further comprises a secondary nozzle 62 capable of ejecting the secondary flow path.

[0066] In order to reduce the braking distance of the aircraft during landing, the nacelle 2 comprises a mechanical cascade thrust reverser system 7.

[0067] More particularly, the role of the mechanical thrust reverser system is to redirect at least a portion of the thrust generated by the turbojet engine 3 towards the front of the nacelle 2, thus creating a counter-thrust.

[0068] For this purpose, cascades 8 are concealed in a movable cowl 9 capable of sliding along rails from a closed position to an open position so as to uncover said cascades, which allows to redirect the secondary air flow towards the upstream of the nacelle 2.

[0069] The closed position is illustrated in FIG. 2A which shows the movable cowl 9 including a plurality of locking flaps 12 forming a joint with said sliding cowl 9.

[0070] A connecting rod 10 is pivotally mounted on the locking flap 12 and onto an inner fixed structure 11 commonly called IFS suitable for surrounding the rear portion of the turbojet engine 3.

[0071] The connecting rod 10 comprises a first joint 101 on the locking flap 12 as well as a second joint 102, corresponding to the connecting rod 10 small end, on the inner structure 11. Thus, in this closed position, the secondary flow is able to circulate in the annular flow path 5 and generate with the primary flow a flow FD generating thrust.

[0072] To generate a counter-thrust, an actuator such as a hydraulic cylinder not shown in FIG. 2B causes the cowl 9 to slide and causes the annular flow path 5 to be closed by the locking flaps 12.

[0073] This consequently leads to the redirection of the secondary flow into a reverse flow, here represented by the reference FI, through the cascades 8 to create the counter-thrust.

[0074] To guarantee the correct operation of the connecting rod 10 and therefore of the reverser, it is advantageous to surround the connecting rod 10 small end by a fitting 13 as illustrated in FIG. 3A. This is a view of a section along the longitudinal axis X.

[0075] A device DIS for attaching the connecting rod 10 small end is located inside the space delimited by the fitting 13.

[0076] The device DIS includes a connection interface 14 forming a pivot connection for the connecting rod 10 small end and a removable fork 19 capable of partially surrounding the connection interface 14.

[0077] More particularly, the connection interface 14 comprises a first recessed or hexagonal socket screw 140 and a first nut 141 capable of cooperating with said first screw 140.

[0078] It is advantageous for the nut 141 to be of a shape capable of cooperating with the shape of the orifice of the fitting 13 into which it is inserted, so as to rotationally lock it.

[0079] The fork 19 therefore has the role of rotationally locking the first screw 140. It is also attached to the fitting 13 and locked in position by holding means comprising in this example a spring pin 21 surrounding a support area 20 integral with the fitting 13 and passing through the fork 19.

[0080] The device DIS for attaching the connecting rod 10 small end also comprises a first ring 16 arranged between the connecting rod 10 small end and the fitting 13, capable of taking up, when the thrust reverser 7 is operational, the forces transmitted by the connecting rod 10 towards the fitting 13 through the first screw 140.

[0081] The first ring 16 is further used as a stopper for the connecting rod 10 to reduce any undesirable movement of the connecting rod 10, in particular angular oscillations.

[0082] A second ring 17 is also arranged between the connecting rod 10 and the fork 19. It allows, initially, to hold said fork 19 in position by holding it in position against a shouldered ring 18 at the fitting 13.

[0083] In a second step, the second ring 17 allows to lock the ball joint of the connecting rod 10 at the fitting 13 by means of the assembly comprising said at least one shoulder of the first screw 140, the first ring 16 and the nut 141.

[0084] The fork 13 therefore has a clearance with the second ring 17, the shouldered ring 18 and with the first screw 140.

[0085] FIG. 3B illustrates an axial view along the axis B as defined in the previous figure.

[0086] The fork 19 includes a first tooth 190 and a second tooth 191 extending along a transverse axis perpendicular to the longitudinal axis of the first screw 140.

[0087] As for the first screw 140, it comprises in this example a shoulder in contact with its base and which is inserted between the first and the second tooth 190, 191, rotationally locking the first screw 140.

[0088] Alternatively, as illustrated in FIG. 4, the first screw 140 comprises a plurality of flat surfaces 25 of hexagonal shape in contact with its base 26.

[0089] In this embodiment, the first screw 140 is, in the same way, inserted between the first and the second tooth 190, 191.

[0090] Another variant is to insert in the first screw 140, as illustrated in FIG. 5A, at least one housing 27 of rounded shape which extends perpendicularly to the longitudinal axis of said screw 140.

[0091] The fork 19 here comprises a single rod 193 which is inserted into said housing 27 to rotationally lock the first screw 140 as shown in FIG. 5B.

[0092] It should be noted that the housing 27 can be a through housing, which allows to double the number of positions wherein the rod 193 can be inserted into the housing 27.

[0093] Moreover, as an alternative to the spring pin 21, mention can be made of a second screw 22 capable of cooperating with a second nut 23 as illustrated in FIG. 6.

[0094] Optionally, a lockwire can be placed between the second nut 23 and the fork 19 to improve the holding of the second screw 22.

[0095] Another variant is to use rivets 24 as means for holding the fork 19 as illustrated in FIG. 7.

[0096] FIG. 8A illustrates an embodiment of the connecting rod 10 small end according to the invention.

[0097] The connecting rod 10 small end here includes at least two projections 28 perpendicular to the longitudinal axis of the connecting rod 10.

[0098] As illustrated in FIG. 8B which shows an axial view along the longitudinal axis X, by contacting the two projections 28 with the fork 19, the angular oscillations of the connecting rod 10 are reduced.

[0099] This also has the advantage of reducing the dimensions of other mechanical parts, in particular the width of the first ring 16. The width of the fitting 13 is therefore reduced while improving its aerodynamic profile.