Aircraft landing gear and method for controlling an olive-shaped catching pin in an aircraft landing gear

Description

[0001] The invention relates to an aircraft landing gear, as well as a method for controlling an olive in an aircraft landing gear. BACKGROUND OF THE INVENTION

[0002] Aircraft include several moving parts between a deployed and retracted position, such as landing gear, doors, and wingtips. These moving parts are equipped with a suitable locking tab, for at least one of the aforementioned positions, designed to be hooked by a locking hook on the aircraft structure to secure the moving parts in position.

[0003] The olive is generally shaped like a body of revolution with an axial opening, allowing it to rotate freely on a spindle mounted on the moving element. This enables it to roll on the hook during docking or release. However, cases of the olive seizing on the spindle have been observed, generating friction between the olive and the hook during operation, sometimes making it difficult to release the olive.

[0004] To avoid this situation, it is known to mount the freely rotating spindle in the yokes that receive its ends, thus allowing the entire olive and spindle assembly to rotate if the olive seizes on the spindle. However, such a solution is not satisfactory in operation. In particular, it is difficult for an operator to verify whether the spindle is blocked or freely rotating during an inspection. Furthermore, the free rotation of the spindle makes it impractical to use it as a lubrication channel for the olive. SUBJECT OF THE INVENTION

[0005] The invention aims to provide an olive that reduces the aforementioned disadvantages. PRESENTATION OF THE INVENTION

[0006] To achieve this goal, an aircraft landing gear as claimed in claim 1 is proposed, as well as a method for controlling an olive in an aircraft landing gear as claimed in claim 10. Said landing gear includes in particular an olive intended to be mounted on a movable element to be hooked by a locking hook in order to immobilize the movable element in a given position, the olive having a body provided with a longitudinal orifice for its mounting on a pin, and an external surface of revolution having a central portion of convex profile with which the hook cooperates, characterized in that the central portion of the external surface is formed on a central ring attached to free rotation on a central bearing surface of the body.

[0007] Thus, even if the olive body becomes stuck on the spindle onto which it is threaded, the central ring can still rotate freely on the body so as to roll on the hook. The invention therefore allows for double rotation, without a freely rotating spindle.

[0008] Moreover, the free rotation inspection of the body and the central ring is very simple and is suitable for routine pre-flight checks.

[0009] According to a particular aspect of the invention, the external surface of the olive comprises a first lateral portion formed on one side of the central ring on a portion made of material with the body, and a second lateral portion formed on the other side of the central ring on an auxiliary ring attached for free rotation on an auxiliary bearing of the body.

[0010] If necessary, the central span and the auxiliary span are formed on the same cylindrical surface.

[0011] According to a first variant embodiment, the first lateral portion, the central portion and the second lateral portion of the external surface give it a convex profile without breaks.

[0012] By convex profile "without break", we mean a convex profile that is substantially smooth, that is to say, varying in a continuous and relatively progressive manner, without step or other break in the profile.

[0013] According to a second embodiment, the first and second lateral portions of the external surface extend along cylindrical surfaces.

[0014] According to a particular embodiment, the body is made of steel, while the central ring is made of a material suitable for friction and resistant to seizing.

[0015] The invention also relates to a method of mounting (not claimed) an olive according to the invention, comprising mounting the olive freely rotating on the spindle of the moving element, the spindle being immobilized against rotation on the moving element. DESCRIPTION OF THE FIGURES

[0016] The invention will be better understood in light of the following description of a particular embodiment of the invention, with reference to the figures in the accompanying drawings, among which: there figure 1 is a front view of a movable element equipped with an olive according to a first particular embodiment of the invention, as it approaches the hook of a locking housing, one of the guides of the locking housing having been removed for clarity; the figure 2 is a longitudinal cross-sectional view of the olive of the figure 1 received in the locking case hook, the gaps having been exaggerated for clarity; the figure 3 is a view analogous to that of the figure 1 illustrating only the olive itself; the figure 4 is a view analogous to that of the figure 3 of a variant embodiment of the olive of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] With reference to figures 1, 2 And 3 The olive 100 of the invention is of revolution and comprises a body 101 having a cylindrical longitudinal orifice 120 for being threaded onto a pin 1 mounted on two clevises 2 of a movable element 3, for example, an aircraft landing gear. The olive 100 is intended to be hooked by a hook 4 of a locking housing 5 when the movable element 3 reaches a position in which it must be immobilized and locked. To this end, the locking housing 5 has guides 6 on either side of the hook 4 to guide the olive 100 during the engagement of the hook 4.

[0018] According to the invention, the body 101 comprises an external cylindrical surface 102 defining successively a central bearing surface 103 and an auxiliary bearing surface 104. The central bearing surface 103 is axially limited by a shoulder 105 formed by a face of a lateral protrusion 106 of the body 101. On the central bearing surface 103 and the auxiliary bearing surface 104 are threaded a central ring 107 and an auxiliary ring 108 received to rotate freely about the same axis of rotation.

[0019] The central ring 107 is designed to come into contact with the hook 4, while the protrusion 106 and the auxiliary ring 108 are designed to come into contact with the guides 6. The central ring 107 is free to rotate on the body 101 so that if the latter seizes on the spindle 1, the central ring 107 can still rotate when in contact with the hook 4. This provides rotational redundancy, which does not require the spindle 1 to be mounted for rotation in the clevises 2 of the moving element 3, so that the spindle 1 can be mounted in a rotationally fixed position in the clevises 2. Similarly, the rotational mounting of the auxiliary ring 108 on the body 101 allows relative rotation of the external surfaces of the protrusion 106 and the auxiliary ring 108, which facilitates the rolling of the olive 100 along the guides 6.

[0020] Moreover, it is easy for operators to verify the free rotation of the body on the spindle, as well as the free rotation of the bushings on the body. The verification procedure consists of blocking the rotation of the central bushing 107 with one hand and rotating the protrusion 106 and the lateral bushing 108 with the other. This procedure allows for the verification of all sliding paths without risk of error. The detection of blockages is therefore considerably facilitated.

[0021] Here, and according to a first variant of the implementation particularly visible at the figure 3 The lateral protrusion 106, the central ring 107, and the auxiliary ring 108 have respective external surfaces 109, 110, and 111, each defining portions (respectively, two lateral portions framing a central portion) of an external surface of the olive having a continuous convex profile. In the illustrated embodiment, the profile is an arc of a circle, and therefore has a constant radius of curvature R, but any other continuous convex profile is suitable within the scope of the invention.

[0022] According to an alternative embodiment illustrated in the figure 4 The protrusion 106 and the auxiliary ring 108 have a cylindrical external surface, so that only the external surface of the central ring 107 is convex. This arrangement reduces the risk of damage to the external surfaces of the protrusion 106 and the auxiliary ring 108 from excessive contact pressure against the guides 6.

[0023] Manufacturing the olive 100 in several parts allows for the selection of different materials for the body and the bushings. Specifically, the body can be made of steel and the central bushing of a friction-resistant and non-seizing material, such as bronze or a ferrous alloy. Alternatively, self-lubricating bushings can be inserted between the body and the bushings. The friction surfaces of the spindle 1, the body 101, and the bushings 107 and 108 can also be coated directly to facilitate their sliding.

[0024] This multi-part design allows, if necessary, for only the most worn part(s) to be replaced, leaving the others in service.

[0025] The double rotation established according to the invention between the spindle 1 and the olive body 101, and between the olive body 101 and the central ring 107, allows the use of a spindle 1 that is stopped from rotating on the yokes 2. Securing the spindle 1 prevents large displacements between the spindle 1 and the inner diameter of the yokes 2, which can cause damage to the contact surfaces. It is therefore possible to drill a lubrication channel 7 in the spindle 1, opening on one side substantially in the middle of the body 1 and on the other side at one end of the spindle 1, which is equipped with a grease fitting 8. Securing the spindle 1 allows the lubrication hole to be oriented perpendicular to the load, in the neutral plane, and thus increases the strength of the workpiece. It should be noted that, although the radial section of the lubrication channel 7 has been shown in the cross-sectional view of the figure 2 This radial section is positioned in practice to extend perpendicularly to the cutting plane of the figure 2 The protrusion 106 is internally provided with an annular groove 106.1, into which the radial section of the lubrication channel 7 opens, and an axial groove 106.2, with closed ends, into which radial conduits 106.3, 106.4 open, passing through the thickness of the protrusion 106 to open on the opposite side onto the outer surface of the protrusion 106. The two channels 106.3 open opposite an annular groove 107.1 formed inside the ring 107, and the conduit 106.4 opens opposite an annular groove 108.1 formed inside the ring 108. It is understood that: The radial section of the lubrication channel 7, the annular groove 106.1 and the axial groove 106.2 form lubrication means for the interface between the spindle 1 and the body 101; the radial section of the lubrication channel 7, the annular groove 106.1, the axial groove 106.2, the radial conduits 106.3 and the annular grooves 107.1 form lubrication means for the interface between the protrusion 106 and the ring 107; the radial section of the lubrication channel 7, the annular groove 106.1, the axial groove 106.2, the radial conduit 106.4 and the annular groove 108.1 form lubrication means for the interface between the protrusion 106 and the ring 108.

[0026] The invention is not limited to what has just been described, but on the contrary encompasses any variant falling within the scope defined by the claims.

[0027] In particular, although the olives illustrated here have an auxiliary bearing surface extending from the central bearing surface to accommodate an auxiliary ring, the auxiliary bearing surface can extend along a different cylindrical surface than that of the central bearing surface. It is even possible to eliminate both the auxiliary bearing surface and the auxiliary ring, by molding the latter from the body or by shrink fitting, thus forming a second protrusion. The central ring will then advantageously be made in two parts so that it can be attached to the central bearing surface between the two protrusions. Naturally, there is then no longer any possibility of relative rotation between the two protrusions.

[0028] Alternatively, the protrusion can be removed and replaced on the body by a second auxiliary bearing adapted to receive a second freely rotating auxiliary ring.

[0029] Although the external surface of the two lateral portions 109, 111 on either side of the central portion 110 has been described as extending with the central portion along a convex profile without break, it is possible to foresee another profile, varying gradually or not (presence then of a break like a step).

[0030] Guides 6 are optional.

[0031] The invention relates to any aeronautical device comprising a fixed element on which is mounted a movable element provided with an olive according to the invention, a locking hook being connected to the fixed element to hook the olive and retain the movable element in a given position relative to the fixed element.

[0032] The invention is, for example, applicable to an aircraft landing gear comprising a movable element equipped with such a lug. The movable element is, for example, the landing gear box, the box being articulated to a structure of the aircraft so as to be movable in a manner known per se between a position extended from the landing gear bay and a position retracted into the landing gear bay, the lug being hooked by the locking hook when the box is in the retracted position to hold the box in that position.

[0033] The moving element can also be an aircraft cargo door or any other moving part of an aircraft. The invention also applies to fields other than vehicles.

Claims

1. Aircraft landing gear, comprising a landing gear (3) provided with a yoke supporting a spindle on which is mounted a capture pin (100) to be hooked by a hook (4) of a locking box (5) intended to be mounted on the structure of the aircraft in order to immobilise the landing gear in a given position with respect to said structure; the capture pin comprising a body (101) provided with a longitudinal opening (120) enabling it to be mounted on the spindle (1), and an outer surface (109, 110, 111) of revolution having a central portion (110) having a convex profile to cooperate with the hook, capture pin wherein the central portion (110) of the outer surface is formed on a central ring (107) which is mounted so as to rotate freely on a central portion (103) of the body.

2. Landing gear according to claim 1, wherein the outer surface of revolution of the capture pin comprises two side portions (109, 111) on either side of the central portion (110) extending with the central portion according to a fracture-free convex profile.

3. Landing gear according to claim 2, wherein the fracture-free convex profile has a constant curvature (R) .

4. Landing gear according to claim 1, wherein the outer surface of revolution of the capture pin comprises two side portions (109, 111) on either side of the central portion (110), the two side portions (109, 111) extending along cylindrical surfaces.

5. Landing gear according to claim 1, wherein the body also supports an auxiliary bearing surface (104) on which an auxiliary ring (108) is received rotating freely, coaxially to the central ring.

6. Landing gear accordng to claim 5, wherein the central bearing surface (103) and the auxiliary bearing surface (104) are formed on one same cylindrical outer surface (102) of the body.

7. Landing gear according to claim 1, wherein the body (101) is made of steel, while the central ring is made of a material adapted to friction and resistant to seizing.

8. Landing gear according to claim 1, in which the spindle is immobilised in rotation on the landing gear.

9. Landing gear according to claim 8, in which the spindle (1) is provided with a lubrication channel (7) opening onto an end of the spindle.

10. Method for controlling a capture pin in a landing gear according to one of the preceding claims, comprising the verification of the free rotation of the different parts of the capture pin.

11. Method according to claim 10, comprising the verification of the free rotation of the body on the spindle, as well as the free rotation of each ring on the body.