Aircraft landing gear with a leaf spring locking device

Description

[0001] The present invention relates to the field of landing gear and more particularly to means of locking the landing gear in the deployed position. BACKGROUND OF THE INVENTION

[0002] Aircraft landing gear is known to include a leg that can be moved movably on the structure of an aircraft between a deployed position (for takeoff and landing) and a retracted position (for flight) under the action of a maneuvering actuator.

[0003] The leg is held in the deployed position by a breakaway strut which is attached to the leg and the aircraft structure, and which has two connecting rods articulated together and held in an aligned position by a stabilizing device.

[0004] The stabilizing device comprises two connecting rods articulated together and held in a substantially aligned position by a passive locking device in order to prevent misalignment of the counter brace.

[0005] In general, the locking mechanism includes one or more helical springs having ends connected to the strut and the stabilizing element to exert a tensile force on said stabilizing element and thus prevent misalignment of the connecting rods.

[0006] It is common for the lander to be designed to move by gravity from the retracted to the deployed position in the event of a maneuvering actuator failure. Helical springs are typically used to assist the lander's movement to the deployed position and to lock it in that position.

[0007] That being said, helical springs are particularly bulky and oppose the action of the maneuvering actuator when raising the lander, their linear behavior implying significant additional forces to counteract when moving the lander to the retracted position for which the maneuvering actuator must be dimensioned.

[0008] Moreover, helical springs have limited radial stiffness and are particularly vulnerable to bird strikes and other debris, such as that generated by a tire blowout. They can also suffer fatigue failure due to vibrations from landing gear operation or aerodynamic effects, and interfere with nearby components. US9862483B2 discloses an aircraft landing gear that includes a composite fiber leaf spring arranged as a downward-facing locking spring to achieve the locking link. SUBJECT OF THE INVENTION

[0009] The invention therefore aims to provide an aircraft landing gear that at least partially overcomes the aforementioned drawbacks. SUMMARY OF THE INVENTION

[0010] To this end, an aircraft landing gear is proposed comprising: a leg arranged to be mounted movably on an aircraft structure between a deployed position and a retracted position; at least one bracing member to maintain the leg in the deployed position, comprising a first connecting rod articulated on the aircraft structure and a second connecting rod articulated on the first connecting rod and on the leg; a stabilizing member to maintain the first and second connecting rods in an aligned position, comprising a first connecting rod and a second connecting rod articulated with each other, and of which the second connecting rod is articulated on the first connecting rod; and at least one spring to elastically return the articulations of the first and second connecting rods to a generally aligned position.

[0011] According to the invention, the spring is a leaf spring arranged to be brought to an elastically deformed state under a bending force when the joints of the first and second connecting rods leave their generally aligned position, and to escape the bending force and be in a state of least deformation when the leg is between the retracted position and an intermediate position between the retracted and deployed positions.

[0012] Thus, the bending force to which the spring is subjected only temporarily opposes the lifting of leg 2, which makes it possible to limit the forces to be countered during the movement of the lander towards the retracted position for which a maneuvering actuator must be sized.

[0013] Furthermore, leaf springs are much less vulnerable to bird strikes and debris from a tire blowout than coil springs. They are also more compact, making them easier to integrate.

[0014] According to a particular embodiment of the invention, the leaf spring has one end rigidly fixed to the first connecting rod, and an opposite end permanently supported by a first arm of a rocker arm mounted to rotate freely about the articulation axis of the first connecting rod and the second connecting rod. The rocker arm is rotationally linked to the first connecting rod when the leg is between the retracted and intermediate positions, and rotationally linked to the second connecting rod when the leg is between the intermediate and extended positions.

[0015] In particular, the rocker has a second arm resting against a surface of the first connecting rod when the leg is between the retracted position and the intermediate position, and resting against a surface of the second connecting rod when the leg is between the intermediate position and the deployed position.

[0016] According to a particular characteristic, the leaf spring is a metal plate having a substantially constant thickness and a width that evolves in a generally linear fashion.

[0017] In particular, the end of the leaf spring is rigidly fixed to the first connecting rod via a fastening device comprising a base fixed to the first connecting rod and a leaf support fixed to the end of the leaf spring. The fastening support has, in its front part, a contact surface arranged to cooperate with a contact surface of the base and allow the leaf support to pivot on the base about an axis substantially perpendicular to a longitudinal axis of the leaf spring, and has, in its rear part, an oblong hole arranged to be passed through by a screw in order to rigidly fix the leaf support to the first connecting rod and allow the leaf support to pivot when the screw is tightened and loosened.

[0018] In particular, the volume occupied by the leaf spring and rocker when the leg is in the deployed position is contained within the volume swept by the first connecting rod when the leg moves from the retracted position to the deployed position.

[0019] According to another particular embodiment of the invention, the leaf spring has one end rigidly fixed to the second connecting rod, and an opposite end permanently bearing against a sliding profile of a cam mounted freely to rotate about the articulation axis of the first and second connecting rods. The cam is rotationally bound to the second connecting rod when the leg is between the retracted and intermediate positions, and rotationally bound to the first connecting rod when the leg is between the intermediate and extended positions.

[0020] In particular, the cam has a rotating drive surface bearing against a surface of the first connecting rod when the leg is between the intermediate position and the deployed position, and bearing against a surface of the second connecting rod when the leg is between the retracted position and the intermediate position.

[0021] According to a particular characteristic, the leaf spring comprises a plurality of superimposed leaves having an overall constant width and different lengths.

[0022] In particular, the lander includes two leaf springs to provide redundancy in case one of the two leaf springs fails.

[0023] In particular, the two leaf springs are virtually identical.

[0024] The invention also relates to an aircraft comprising at least one such landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which: [ Fig. 1 ] there figure 1 is a side view of an aircraft landing gear according to a first embodiment of the invention, shown in the retracted position; [ Fig. 2 ] there figure 2 is a view analogous to the figure 1 showing the lander in an initial intermediate position at the beginning of the deployment phase; [ Fig. 3 ] there figure 3 is a view analogous to the figure 1 showing the lander in a second intermediate position at the end of the deployment phase; [ Fig. 4 ] there figure 4 is a view analogous to the figure 1 showing the lander in the deployed position; [ Fig. 5 ] there figure 5 is a perspective view of part of the lander illustrated in the figure 4 ; Fig. 6 ] there figure 6 is a perspective view of a device for attaching the leaf spring to the bracing member; [ Fig. 7 ] there figure 7 is a side view of part of an aircraft landing gear according to a second embodiment of the invention, shown in deployed position. DETAILED DESCRIPTION OF THE INVENTION

[0026] With reference to figures 1 à 4 An aircraft landing gear 1 comprises, in a manner known per se, a leg 2 having a first end bearing wheels R and, opposite, a second end articulated to an aircraft structure 3 along a substantially horizontal articulation axis X1 in operation. The leg 2 is movable between a retracted position illustrated in the figure 1 and a deployed position illustrated at the figure 4 The leg 2 is held in the deployed position by means of a bracing element 4 comprising a first connecting rod 4a articulated to the aircraft structure 3 along a pivot axis X2 and a second connecting rod 4b articulated to the leg 2 and to the first connecting rod 4a along respective pivot axes X3 and X4. In the deployed position, the first connecting rod 4a and the second connecting rod 4b are substantially aligned.

[0027] A rotary actuator 5 is mounted for free rotation on the aircraft structure 3 along a rotation axis X5 parallel to the articulation axes X1-X4. The actuator 5 comprises a housing with an appendage forming a first connecting rod 6a, and includes a shaft mounted to rotate about the rotation axis X5 and carrying a crank 7. The relative angular position between the first connecting rod 6a and the crank 7 can be changed by supplying power to the actuator 5 to rotate the shaft relative to the housing. The first connecting rod 6a is coupled to the first connecting rod 4a of the bracing member 4 by means of a second connecting rod 6b articulated to the first connecting rod 6a along a articulation axis X6 and articulated to the first connecting rod 4a along a articulation axis X7. The crank 7 is attached to the leg 2 by means of another connecting rod 8 articulated on the crank 7 along an axis X8 of articulation and articulated on a horn of the leg 2 along an axis X9 of articulation.All axes X1 to X9 are parallel to each other here.

[0028] In the position illustrated at the figure 4 In which leg 2 is in the deployed position, the relative angular position of the connecting rod 6a and the crank 7 is such that the connecting rods 6a and 6b are in a substantially aligned position, known as the first alignment. As is known, the first alignment is a position obtained by moving the connecting rods 6a and 6b slightly beyond their geometric alignment (which is defined by the perfect alignment of the axes X5, X6, and X7 in the same plane) to bring them against their respective stops. The connecting rods 6a and 6b thus form a stabilizing element 6 that maintains the connecting rods 4a and 4b of the bracing element 4 in a substantially aligned position, thereby stabilizing leg 2 in the deployed position.

[0029] However, the shaft is blocked by the crank 7, which is itself blocked from rotation by its connection to the leg 2 via the connecting rod 8 which is not aligned with the crank 7.

[0030] To raise leg 2 to the retracted position, actuator 5 is powered to rotate the shaft and thus change the relative angular position of connecting rod 6a and crank 7. As illustrated in figures 2 And 3 This rotation has the initial effect of breaking the alignment of the connecting rods 6a and 6b of the stabilizing member 6, and therefore breaking the alignment of the connecting rods 4a and 4b of the bracing member 4. Leg 2 is thus no longer stabilized in the deployed position and can be raised to the retracted position. With the actuator 5 continuing to be powered, the second connecting rod 6b pulls on the connecting rod 4a while the connecting rod 8 pushes on leg 2, which has the effect of raising said leg 2 to the retracted position illustrated in the figure. figure 1 .

[0031] When leg 2 is retracted, the relative angular position of connecting rod 6a and crank 7 is such that crank 7 and connecting rod 8 are in a substantially aligned position, known as the second alignment. Similar to the first alignment, the second alignment is achieved by moving crank 7 and connecting rod 8 slightly beyond their geometric alignment (defined by the perfect alignment of axes X5, X8, and X9 in the same plane) to bring them against their respective stops. This alignment locks leg 2 in the retracted position, ensuring stability and eliminating the need for a locking mechanism.

[0032] According to the invention, the connecting rods 6a, 6b are held in a substantially aligned position by a locking member 10 which returns the connecting rods 6a, 6b to the locked position illustrated in the figure 4 and defined by the respective stops of said connecting rods 6a, 6b.

[0033] The locking member 10 includes a spring for elastically holding the connecting rods 6a, 6b in a substantially aligned position. The spring includes an elongated metal blade 11 that extends along the connecting rod 4a ( figure 5 The blade 11 exhibits a generally constant thickness and a variable width, the width extending substantially along the X1-X9 axes and being greater than the thickness. The width of the blade 11 varies linearly in order to homogenize the mechanical stresses experienced by the blade 11 when it is subjected to the bending force P described later. The blade 11 thus comprises a first end 11.1 with a large width and a second end 11.2 with a small width. The first end 11.1 is rigidly fixed (fixed joint) to the connecting rod 4a near the pivot axis X2. The second end 11.2 carries a pad 11.3 positioned near the pivot axis X7.

[0034] The locking member 10 further includes a rocker 12 mounted to rotate freely about the axis X7 of articulation of the bracing member 4. The rocker 12 is substantially L-shaped and comprises a first arm 12.1, one end of which is permanently supported against the pad 11.3 of the blade 11, and a second arm 12.2, one end of which is supported against a surface S4 of the connecting rod 4a and / or a surface S6 of the connecting rod 6b depending on the relative angular position of the connecting rod 4a and the connecting rod 6b ( figure 1 ).

[0035] The deployment of leg 2 will now be detailed.

[0036] When lander 1 is between the retracted position illustrated in the figure 1 (in which leg 2 describes an extension angle β equal to 0°) and the first intermediate position illustrated in the figure 2 (in which the extension angle β of leg 2 is substantially equal to 39.5°), the relative angular position of connecting rod 4a and connecting rod 6b is such that the first arm 12.1 of rocker 12 is in contact with the pad 11.3 of blade 11 while the second arm 12.2 of rocker 12 is only in contact with the surface S4 of connecting rod 4a, so that rocker 12 and connecting rod 4a have a unified rotational movement around the axis X7, blade 11 being slightly flexed and exhibiting a minimum deflection F.

[0037] When lander 1 is in the first intermediate position ( figure 2 ), the relative angular position of the connecting rod 4a and the connecting rod 6b is such that the first arm 12.1 of the rocker 12 is in contact with the pad 11.3 of the blade 11 while the second arm 12.2 of the rocker 12 is in contact with both the surface S4 of the connecting rod 4a and the surface S6 of the connecting rod 6b, so that the deflection F of the blade 11 remains unchanged and is always minimal.

[0038] When lander 1 is between the first intermediate position ( figure 2 ) and the second intermediate position illustrated in the figure 3 (in which the extension angle β of leg 2 is substantially equal to 98.5°), the relative angular position of connecting rod 4a and connecting rod 6b is such that the first arm 12.1 of rocker 12 is in contact with the pad 11.3 of blade 11 while the second arm 12.2 of rocker 12 is only in contact with the surface S6 of connecting rod 6b, so that rocker 12 and connecting rod 6b have a joint rotational movement around the axis X7, rocker 12 then exerting on blade 11 a bending force P which tends to increase as the lander 1 approaches the second intermediate position, and thus to cause an increase in the deflection F of blade 11.

[0039] When lander 1 is in the second intermediate position ( figure 3 ), the bending force P exerted by the first arm 12.1 of the rocker 12 on the blade 11 is maximum, so that the deflection F of the blade 11 is maximum.

[0040] When lander 1 is between the second intermediate position ( figure 3 ) and the deployed position illustrated in the figure 4 (in which the extension angle β of leg 2 is approximately equal to 103.5°), the relative angular position of connecting rod 4a and connecting rod 6b is such that the first arm 12.1 of rocker 12 is supported against the pad 11.3 of blade 11, while the second arm 12.2 of rocker 12 is always supported only against the surface S6 of connecting rod 6b, so that rocker 12 and connecting rod 6b continue to have a unified rotational movement around the axis X7, which tends to decrease the bending force P exerted by the first arm 12.1 of rocker 12 on blade 11 as the lander 1 approaches the deployed position, and therefore to cause a decrease in the deflection F of blade 11, which tends to pull connecting rods 6a, 6b towards the locked position.

[0041] Thus, blade 11 works elastically in bending and tends to return to its resting state. For this reason, blade 11 is slightly flexed when connecting rods 6a, 6b are in a substantially aligned position ( figure 4 ), and takes on a more arched shape when the connecting rod 6b pivots around the X7 axis ( figure 3 ).

[0042] The blade 11 thus forms a leaf spring subjected elastically to a bending force P via the rocker arm 12 when the connecting rods 6a, 6b leave their substantially aligned position. The arrangement of the rocker arm 12 allows the bending force P exerted on the blade 11 to be temporarily linked to the rotation of the connecting rod 6b, and therefore limits the force required from the actuator 5 during the retraction of the leg 2.

[0043] The actuator 5 is dimensioned to break the alignment of the connecting rods 6a, 6b by counteracting the bending force P exerted by the rocker 12 on the blade 11. The misalignment of the connecting rods 6a, 6b causes the misalignment of the connecting rods 4a, 4b and therefore the pivoting of the leg 2 towards the retracted position.

[0044] It should be noted that whatever the position of the lander 1, the blade 11 is held by the rocker 12 in a state of at least minimal deformation so as to ensure permanent contact between the blade 11 and said rocker 12 and thus avoid any separation due to vibrations during flight.

[0045] It should also be noted that the volume occupied by the blade 11 and the rocker 12 when the lander 1 is in the deployed position is contained within the volume swept by the connecting rod 4a when the lander 1 moves from the retracted to the deployed position. Such a locking device 10 therefore does not, unlike helical springs, interfere with the integration of other equipment and proves to be particularly well protected from external damage, the blade 11 and the rocker 12 being arranged in the storage compartment of the lander 1 and the connecting rod 4a acting as a shield against bird strikes and tire debris projections ( figure 5 ).

[0046] There figure 6 illustrates a device 20 for fixing the blade 11 to the connecting rod 4a, facilitating the removal and replacement of the blade 11, which is pre-loaded onto the connecting rod 4a by the rocker arm 12. The device 20 is also visible in operation at the figure 5 .

[0047] The device 20 includes a generally flat base 21 arranged to be fixed to the first connecting rod 4a via three screws V1. The base 21 has in its front part a male contact surface 21.1 formed by two half-cylinders 21.2 extending outward from a superior surface of the base 21. The two half-cylinders 21.2 extend along the same axis X which, in operation, is substantially perpendicular to the longitudinal axis of the blade 11.

[0048] The device 20 further includes a blade support 22, generally U-shaped, for receiving the end 11.1 of the blade 11 and being fixed to the blade 11 by means of two screws V2. The blade support 22 has, at its front, a rounded female contact surface 22.1 arranged to cooperate with the male contact surface 21.1 of the base 21 and to allow the blade support 22 to pivot on the base 21 substantially around the X-axis.

[0049] The sole 21 and the blade support 22 have in their rear part an oblong hole 21.3, 22.3 arranged to be crossed by the same screw V3 in order to fix the blade support 22, and therefore the blade 11, to the connecting rod 4a and allow pivoting around the X axis of the blade support 22 on the sole 21 when screwing and unscrewing the screw V3.

[0050] The screw V3 is long enough so that, during its loosening, the blade support 22 pivots around the X-axis under the effect of the bending force P exerted by the rocker 12 on the end 11.2 of the blade 11, until the blade 11 returns to its rest position. Conversely, the screw V3, when tightened, generates and adjusts the bending force P exerted by the rocker 12 on the end 11.2 of the blade 11 to pre-tension said blade 11. Once the screw V3 is properly tightened, two additional screws V4, passing through oblong holes in the device 20 and the blade 11, are added, thus providing redundancy in the fastening of the blade 11 in case one of the screws V3 or V4 fails.

[0051] Therefore, dismantling and replacing blade 11 does not require the use of any specific tools.

[0052] There figure 7 illustrates another embodiment of the invention in which the lander 1 comprises, in place of the locking member 10, a locking member 10' to maintain the connecting rods 6a, 6b in substantially aligned position.

[0053] The locking member 10' comprises an elongated spring with a plurality of overlapping blades 11' extending along the connecting rod 6b. The blades 11' have a generally constant width and different lengths so as to homogenize the mechanical stresses experienced by the blades 11' when subjected to the bending force P' described later. A first end 11.1' of the spring is rigidly fixed to the connecting rod 6b near the pivot axis X6, and a second end 11.2' opposite the first end 11.1' carries a pad 11.3' located near the pivot axis X7.

[0054] The locking member 10' further includes a cam 12' fixed to the connecting rod 4a so that the cam 12' and said connecting rod 4a have a rotational movement together around the axis X7 of articulation of the bracing member 4. The cam 12' has a sliding profile 12.1' against which the pad 11.3' is in permanent bearing.

[0055] The deployment of leg 2 will now be detailed.

[0056] When lander 1 is in the retracted position ( figure 1 ) and the first intermediate position ( figure 2 ), the 12.1' sliding profile of the 12' cam is such that the distance separating the 11.3' pad from the X7 articulation axis is minimal, so that the 11' blades are slightly flexed and have a minimal F' deflection.

[0057] When lander 1 is between the first intermediate position ( figure 2 ) and the second intermediate position ( figure 3 ), the sliding profile 12.1' of the cam 12' is such that the distance separating the pad 11.3' from the pivot axis X7 tends to increase as the lander 1 approaches the second intermediate position, and thus to cause an increase in the deflection F' of the blades 11'.

[0058] When lander 1 is in the second intermediate position ( figure 3 ), the bending force P' exerted by the cam 12' on the blades 11' is maximum, so that the deflection F' of the blades 11' is maximum.

[0059] When lander 1 is between the second intermediate position ( figure 3 ) and the deployed position ( figure 4), the sliding profile 12.1' of the cam 12' is such that the distance separating the pad 11.3' from the pivot axis X7 tends to decrease as the lander 1 approaches the deployed position, and therefore to cause a decrease in the deflection F' of the blades 11' which tends to return the connecting rods 6a, 6b towards the locked position.

[0060] Thus, the blades 11' work elastically in bending and tend to return to their resting state. To this end, the blades 11' are slightly flexed when the connecting rods 6a, 6b are in a substantially aligned position, and take on a more arched shape when the connecting rod 6b pivots around the axis X7.

[0061] The blades 11' thus form a leaf spring subjected elastically to a bending force P' via the cam 12' when the connecting rods 6a, 6b leave their substantially aligned position. The arrangement of the cam 12' allows the bending force P' exerted by the cam 12' on the blades 11' to be temporarily linked to the rotation of the connecting rod 6b, and therefore limits the force required from the actuator 5 during the retraction of the leg 2.

[0062] The actuator 5 is dimensioned to break the alignment of the connecting rods 6a, 6b by counteracting the bending force P' exerted by the cam 12' on the blades 11'. The misalignment of the connecting rods 6a, 6b causes the misalignment of the connecting rods 4a, 4b and therefore the pivoting of the leg 2 towards the retracted position.

[0063] It should be noted that regardless of the position of the lander 1, the blades 11' are subjected to a bending force P' exerted by the cam 12' in order to ensure permanent contact between the blades 11' and said cam 12' and thus avoid any separation due to vibrations during flight.

[0064] It should also be noted that the volume swept by the blades 11' and the cam 12' when the lander 1 moves from the retracted to the deployed position is contained within the volume swept by the connecting rod 6b under the same conditions. Such a locking mechanism 10' therefore does not interfere with the integration of other equipment and is particularly well protected from external damage, as the blades 11' and the cam 12' are housed within the lander 1's storage compartment, and the connecting rod 6b acts as a shield against bird strikes and tire debris.

[0065] The 11' blades will for example be fixed to the connecting rod 6b by a fixing device similar to the fixing device 20 in order to facilitate the removal and replacement of the 11' blades mounted pre-stressed on the connecting rod 6b by the cam 12' and using only standard tools.

[0066] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0067] The number, shape, and dimensions of the blades 11, 11' may differ from those illustrated. For example, a second blade identical to blade 11 may be fixed to the connecting rod 4a symmetrically to blade 11 and be in permanent contact with the rocker arm 12 to provide redundancy in case of failure of one of the two blades. Alternatively, blade 11 may have a constant width and / or a variable thickness, for example, a parabolic profile.

[0068] Although here the blade 11 extends along the connecting rod 4a, it can also extend along the connecting rod 6b.

[0069] Although here the blades 11' extend along the connecting rod 6b, it can also extend along the connecting rod 4a.

[0070] The stabilization of leg 2 can also combine the action of the rocker 12 and one or more blades 11 fixed on the connecting rod 4a with that of the cam 12' and one or more blades 11' fixed on the connecting rod 6b.

[0071] The 11, 11' blades can be made of any suitable material (metal, composite...).

[0072] The blades 11, 11' can be fixed to the connecting rod 4a and the connecting rod 6b by any suitable means.

[0073] Although the leg 2 is here held in the deployed position by a single bracing member 4, the invention can also be applied to landers comprising a leg held in the deployed position by several bracing members. At least one of the bracing members is then equipped with a locking member 10, 10' comprising at least one leaf spring.

[0074] The pivoting of the blade support 22 on the base 21 can also be ensured by a female contact surface carried by the base and a male contact surface carried by the blade support.

Claims

1. Landing gear (1) for an aircraft, comprising: . a strut (2) arranged to be mounted on an aircraft structure (3) so as to move between an extended position and a retracted position; . at least one bracing member (4) to hold the strut in the extended position, comprising a first connecting rod (4a) configured to be hinged on the structure of the aircraft and a second connecting rod (4b) hinged on the first connecting rod and on the strut; . a stabilising member (6) to hold the first and second connecting rods (4a, 4b) in the aligned position, comprising a first link rod (6a) and a second link rod (6b) hinged together, and the second link rod of which is hinged on the first connecting rod; and . at least one spring to resiliently return the hinges of the first and second link rods into the generally aligned positions; wherein the spring is a leaf spring (11, 11') arranged to be brought into a resiliently deformed state under a bending force (P, P') when the hinges of the first and second link rods move from their generally aligned position, characterised in that the spring is arranged to avoid being subjected to the bending force and be in one same state of lesser deformation when the strut is between the retracted position and an intermediate position comprised between the retracted position and the extended position.

2. Landing gear (1) according to claim 1, wherein the leaf spring (11) has an end (11.1) rigidly fixed to the first connecting rod (4a), and an opposite end (11.2) permanently bearing on a first arm (12.1) of a pivoting arm (12) mounted rotatably free about the hinge axis (X7) of the first connecting rod (4a) and of the second link rod (6b), the pivoting arm being rotatably linked to the first connecting rod (4a) when the strut is between the retracted position and the intermediate position, and rotatably linked to the second link rod (6b) when the strut (2) is between the intermediate position and the extended position.

3. Landing gear (1) according to claim 2, wherein the pivoting arm (12) has a second arm (12.2) bearing against a surface (S4) of the first connecting arm when the strut (2) is between the retracted position and the intermediate position, and bearing against a surface (S6) of the second link rod when the strut (2) is between the intermediate position and the extended position.

4. Landing gear (1) according to claim 2 or 3, wherein the leaf spring (11) is a metal plate having a substantially constant thickness and a width developing mainly linearly.

5. Landing gear (1) according to any one of claims 2 to 4, wherein the end of the leaf spring (11) is rigidly fixed to the first connecting rod (4a) via a fixing device (20) comprising a base (21) fixed onto the first connecting rod (4a) and a blade support (22) fixed to the end of the leaf spring (11), the blade support (22) comprising, in the front part, a contact surface arranged to engage with a contact surface of the base and enable a pivoting of said blade support on said base about an axis (X) substantially perpendicular to a longitudinal axis of the leaf spring (11), and comprising, in the rear part, an oblong hole arranged to be passed through by a screw (V3) in order to rigidly fix the blade support to the first connecting rod and enable the pivoting of said blade support during the screwing and the unscrewing of the screw.

6. Landing gear (1) according to any one of claims 2 to 5, wherein the volume occupied by the leaf spring (11) and the pivoting arm (12) when the strut (2) is in the extended position is contained in the volume swept by the first connecting rod (4a) when the strut (2) passes from the retracted position to the extended position.

7. Landing gear (1) according to claim 1, wherein the leaf spring (11') has an end (11.1') rigidly fixed to the second link rod (6b), and an opposite end (11.2') permanently bearing against a sliding profile (12.1') of a cam (12') fixed to the first connecting rod (4a) such that the cam and said first connecting rod have an integral rotation movement about the hinge axis (X7) of the first connecting rod (4a) and of the second link rod (6b).

8. Landing gear (1) according to claim 7, wherein the leaf spring (11') comprises a plurality of superposed blades having a mainly constant width and different lengths.

9. Landing gear (1) according to any one of the preceding claims, comprising two leaf springs (11, 11') to provide a redundancy in case of failure of one of the two leaf springs.

10. Landing gear (1) according to claim 9, wherein the two leaf springs (11, 11') are substantially identical.

11. Aircraft comprising at least one landing gear (1) according to any one of the preceding claims.