Device for latching a movable element
By using movable threaded nuts and elastic return devices on the movable elements of the aircraft, structural damage and performance degradation caused by friction between the threaded nuts and the hook members is solved, and a lightweight and simplified latch device is achieved.
Patent Information
- Application Number
- CN202480006901.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-01-06
- Filing Date
- 2024-01-02
- Publication Date
- 2025-08-12
AI Technical Summary
In the prior art, during deformation of the movable elements of the aircraft such as landing gear and cargo door, friction between the threaded nut and the hook leads to structural damage and degradation of the latch device performance, and traditional elastic link systems increase the weight and complexity of the device.
The threaded nut is movably mounted on the shaft and translated between the two end positions by an elastic return device, limiting the friction between the threaded nut and the hook, and using a coil spring and guide ring to limit the movement of the threaded nut, ensuring precise contact and reducing wear.
Reduces wear between threaded nuts and hooks, improves stability and performance of the latch device, reduces weight and complexity, and ensures reliable fixation of the movable element.
Smart Images
Figure CN120476077A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a device for latching a movable element such as used in an aircraft for holding a landing gear in a retracted position, for holding a cargo door in a closed position, and more generally for holding any movable element of an aircraft in one of its positions. Background Art
[0002] The aircraft has multiple elements, such as landing gear or cargo doors, that can move between a first position and a second position. Figure 1 As shown, these movable elements are conventionally equipped with a threaded nut 1 suitable for being latched by a hook 2 of an attachment case carried by the aircraft structure (or vice versa) to secure the movable element in at least one of the positions mentioned above.
[0003] The threaded nut 1 is generally in the form of a solid of revolution, comprising a convex or cylindrical outer surface intended to cooperate with the hook 2, and an axial hole via which the threaded nut 1 is received so as to rotate freely about an axis X between two cheeks 3 of a support 4 attached to a movable element or an aircraft structure. By extension, any element intended to latch in a similar manner is called a "threaded nut", even if its external form is not that of a threaded nut.
[0004] In use, cargo doors appear to undergo deformations, particularly in flight or during the opening-closing process, which tend to cause the threaded nut 1 to move inside the hook 2. The same is true for landing gears, particularly when they are fixed to relatively flexible structural elements.
[0005] When the movement of the threaded nut 1 is substantially perpendicular to the axis X, the threaded nut 1 will tend to roll on the latching surface of the hook 2 by rotating about the axis X. However, when the movement of the threaded nut is substantially colinear with the axis X, one of two phenomena will result.
[0006] If there is no sliding between the outer surface of the threaded nut 1 and the latching surface of the hook 2, the threaded nut 1 will transmit its entire movement to the hook 2, which may cause structural damage to the hook 2 and / or other components of the attached housing. In addition, when the threaded nut 1 is released, the significant friction between the threaded nut 1 and the hook 2 may degrade the performance of the latching device or even prevent the hook 2 from releasing the threaded nut 1.
[0007] If there is slippage between the outer surface of the threaded nut 1 and the latching surface of the hook 2, the threaded nut 1 will slide on the latching surface of the hook 2. Depending on the friction between the threaded nut 1 and the hook 2, this may cause more or less noticeable wear of the outer surface of the threaded nut 1 and / or the latching surface of the hook 2. This wear may cause adhesion between the threaded nut 1 and the hook 2 and / or dents in the threaded nut 1 and the hook 2, thereby changing the balance. In addition, the friction between the threaded nut 1 and the hook 2 is transmitted to the hook 2 and other components of the attached housing, which may reduce the performance of the latching device.
[0008] In order to overcome the above-mentioned drawbacks, there are latching devices intended to make the fastening of the attachment housing mobile, in order to manage the significant movements of the threaded nut 1 and to hold the attachment housing in place in the absence of the threaded nut 1. In the case of landing gear, this system comprises, for example, elastic links connecting the attachment housing to the aircraft structure, which significantly increase the weight and complexity of the latching device. Summary of the Invention
[0009] The present invention therefore aims to provide a light and simple device for latching a movable element by means of a locking hook, making it possible to at least partially overcome the above-mentioned drawbacks.
[0010] To this end, the invention provides a device for latching a movable element by means of a hook, comprising a threaded nut which is movably mounted on a shaft, translates along the longitudinal axis of the shaft between two end positions and returns to a rest position arranged between the two end positions by means of elastic return means.
[0011] Therefore, when the threaded nut is latched by the hook, any axial force transmitted by the threaded nut to the hook is limited by the stiffness of the elastic return device rather than by the friction between the outer surface of the threaded nut and the latching surface of the hook, thereby reducing wear of the said surfaces.
[0012] In one particular form, the device comprises a collet intended to be attached to the movable element, the collet comprising two cheeks, each bearing an end of a shaft, a threaded nut extending between the two cheeks.
[0013] According to a particular feature, the elastic return means comprise at least one helical spring extending between the threaded nut and one cheek of the collet.
[0014] In one particular embodiment, the ends of the spring are each mounted on a guide ring mounted slidingly on the shaft, the guide ring being arranged so as to ensure the spring is guided without contact with the shaft.
[0015] In one particular form, the elastic return means comprise a first helical spring extending between one of the cheeks and the threaded nut, and a second helical spring extending between the other of the cheeks and the threaded nut.
[0016] Advantageously, the threaded nut comprises a body including an outer surface defined by a first shoulder and a second shoulder, the two shoulders jointly defining a receiving area for the hook. Such a surface is particularly capable of limiting sliding between the threaded nut and the hook, thereby limiting abrasive wear and ensuring a precise contact area between the threaded nut and the hook.
[0017] In one embodiment, the body includes a first collar and a second collar forming a first shoulder and a second shoulder, respectively. The first collar and the second collar each include a frustoconical outer surface to form a guide slope, enabling the hook to engage between the first shoulder and the second shoulder.
[0018] The invention also relates to an aircraft door equipped with such a device.
[0019] The invention also relates to an aircraft landing gear equipped with such a device.
[0020] The invention also relates to an aircraft comprising at least one such door or at least one such landing gear, the hook being fixed to the structure of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention will be better understood from the following description, which is purely illustrative and non-limiting and should be read with reference to the accompanying drawings, in which:
[0022] [ Figure 1 ] Figure 1 is a perspective view of an apparatus for latching a movable element according to the prior art;
[0023] [ Figure 2 ] Figure 2 is a schematic diagram of a door retention system for an aircraft landing gear in a closed position;
[0024] [ Figure 3A ] Figure 3A is a latch for latching according to a specific embodiment of the present invention Figure 2 A perspective view of the landing gear door equipment is shown;
[0025] [ Figure 3B ] Figure 3B yes Figure 3A an axial cross-sectional view of the apparatus shown;
[0026] [ Figure 4A ] Figure 4A yes Figure 3A a perspective view of a variation of the device shown;
[0027] [ Figure 4B ] Figure 4B yes Figure 4A Axial cross-section of the device shown. DETAILED DESCRIPTION
[0028] refer to Figure 2 The invention is described in this example with respect to an aircraft A comprising a landing gear L articulated on a structure S of the aircraft A between a deployed position shown in this example and a retracted position in which the landing gear L is received in a holder H closable by a door T.
[0029] A double-acting jack V is coupled to the door T and is able to move the door T between an open position, which enables the deployment and retraction of the landing gear L, and a closed position, in which the door T closes the retainer H. In a known manner, the door T is maintained in the closed position by an attachment housing B integral with the structure S of the aircraft A. The attachment housing A is provided with a hook C capable of latching a threaded nut 11 integral with the door T when the door T reaches the closed position.
[0030] like Figures 3A to 3B As shown, the threaded nut 11 is in the form of a body of revolution. This body comprises a curved and convex outer surface 11.1, intended to cooperate with the latching surface of the hook C, and a cylindrical longitudinal aperture 11.2, through which a hollow cylindrical shaft 12 passes through the threaded nut 11. This shaft 12 extends along the axis X and has an outer diameter slightly smaller than the diameter of the longitudinal aperture 11.2, so that the threaded nut 11 is mounted on the shaft 12 in a movable and rotatable manner about the axis X, but also in a translational manner along said axis X.
[0031] The shaft 12 has a first end 12.1 and a second end 12.2, the first end 12.1 being received in a collared centering ring 13 mounted in a hole in a first cheek 14.1 of the clamping member 14, and the second end, opposite the first end 12.1, being received in another collared centering ring 13 mounted in a hole in a second cheek 14.2 of the clamping member 14. Thus, the threaded nut 11 extends between the first cheek 14.1 and the second cheek 14.2, and the clamping member 14 is fixed to the door T.
[0032] A screw 15 extends end-to-end through the shaft 12. One end of the screw 15 is provided with a head 15.1 protruding from the first cheek 14.1, and the other end is provided with a threaded portion 15.2 protruding from the second cheek 14.2. A nut 16 is screwed onto the threaded portion 15.2. The screw head 15.1 and the nut 16 abut against the first cheek 14.1 and the second cheek 14.2, respectively, via a bearing washer 17. The screw 15 and the nut 16 form a bolt that is arranged to retain the shaft 12 between the first cheek 14.1 and the second cheek 14.2 of the collet 14.
[0033] A first helical compression spring 18.1, wound around the shaft 12, extends between the first cheek 14.1 and the threaded nut 11. Each end of the first spring is mounted on a collared guide ring 19, which is slidably mounted on the shaft 12 to guide the first spring 18.1 without contacting the shaft 12. One of the guide rings 19 bears against the first end of the threaded nut 11 via a friction washer 20 interposed between the guide ring 19 and the first end of the threaded nut 11, while the other of the guide rings 19 bears against the first cheek 14.1 via another friction washer 20 interposed between the guide ring 19 and the first cheek 14.1. The guide rings 19 are spaced apart by a first distance d1 that ensures movement of the threaded nut 11 toward a first extreme position, where the first distance d1 is zero.
[0034] Similarly, a second helical compression spring 18.2, wound around the shaft 12, extends between the second cheek 14.2 and the threaded nut 11. Each end of the second spring 18.2 is mounted on a collared guide ring 19, which is slidably mounted on the shaft 12 to ensure that the second spring 18.2 is guided without contact with the shaft 12. One of the guide rings 19 bears against the second end of the threaded nut 11 via a friction washer 20 interposed between the guide ring 19 and the second end of the threaded nut 11, while the other of the guide rings 19 bears against the second cheek 14.2 via another friction washer 20 interposed between the guide ring 19 and the second cheek 14.2. The guide rings 19 are spaced apart by a second distance d2, which ensures that the threaded nut 11 can move toward a second extreme position in which the second distance d2 is zero.
[0035] The first spring 18.1 is arranged to exert a first thrust F1 on the threaded nut 11, which is substantially colinear with the axis X and tends to move the threaded nut 11 towards the second cheek 14.2. The first thrust F1 gradually increases as the threaded nut approaches the first cheek 14.1 and, conversely, gradually decreases as the threaded nut 11 moves away from the first cheek 14.1.
[0036] Similarly, the second spring 18.2 is arranged to exert a second thrust F2 on the threaded nut 11, which is substantially colinear with the axis X and tends to move the threaded nut 11 towards the first cheek 14.1. The second thrust F2 gradually increases as the threaded nut 11 approaches the second cheek 14.2 and, conversely, gradually decreases as the threaded nut moves away from the second cheek 14.2.
[0037] Therefore, when at rest, the threaded nut 11 adopts an equilibrium position arranged between the first extreme position and the second extreme position, in which the first thrust F1 exerted by the first spring 18.1 and the second thrust F2 exerted by the second spring 18.2 cancel each other out, and both the first distance d1 and the second distance d2 are non-zero. The threaded nut 11 is said to be "floating".
[0038] In this case, the first spring 18.1 is identical to the second spring 18.2 (same length, same number of turns and diameter, same stiffness, etc.), so that in the equilibrium position, the threaded nut 11 is located in the center between the first cheek 14.1 and the second cheek 14.2. The first distance d1 separating the guide ring 19 from the first spring 18.2 is identical to the second distance d2 separating the guide ring 19 from the second spring 18.2.
[0039] The threaded nut 11 , the shaft 12 , the centering ring 13 , the collet 14 , the screw 15 , the nut 16 , the bearing washer 17 , the first spring 18 . 1 , the second spring 18 . 2 , the guide ring 19 and the friction washer 20 together form a device 10 for latching a door T by means of a hook C.
[0040] It will be appreciated that the axial force transmitted by the threaded nut 11 to the hook C is limited here by the stiffness of the first spring 18.1 and the second spring 18.2, rather than by the friction between the outer surface 11.1 of the threaded nut 11 and the latching surface of the hook C, and is therefore much lower and more stable than with a so-called "fixed" threaded nut. The threaded nut 11 remains stationary relative to the hook C as long as a certain degree of friction is maintained between the threaded nut 11 and the hook C: the friction between the threaded nut 11 and the hook C is beneficial.
[0041] It should be noted that the first distance d1 and the second distance d2 are predetermined so as to be large enough to ensure the functional stroke of the threaded nut 11, thereby being able to limit the force transmission between the threaded nut 11 and the hook C, but also small enough so that in the event of a breakage of one of the first spring 18.1 or the second spring 18.2, the threaded nut 11 remains close enough to its equilibrium position to remain functional.
[0042] It will also be noted that the friction washer 20 enables the threaded nut 11 to rotate about the axis X while controlling a resistive torque opposing the rotation of said threaded nut 11 .
[0043] It should also be noted that the stiffness of the first spring 18.1 and the second spring 18.2 is predetermined so that when the threaded nut 11 is disengaged from the hook C, the first spring 18.1 and the second spring 18.2 maintain the threaded nut 11 in its equilibrium position while minimizing their return force.
[0044] Figure 4A and Figure 4B The device 10' is shown, which is Figures 3A to 3B A variant of the device 10 shown. Device 10 ′ differs from device 10 in that the body of the threaded nut 11 ′ comprises a slightly convex outer surface 11.1 ′ extending between a first shoulder 11.3 ′ and a second shoulder 11.4 ′, defining a receiving area for the hook C. The first shoulder 11.3 ′ and the second shoulder 11.4 ′ are formed by a first collar 11.5 ′ and a second collar 11.6 ′, respectively, defining an engagement area for the hook C. The first collar 11.5 ′ and the second collar 11.6 ′ are shaped so as to ensure that the threaded nut 11 ′ is centered relative to the hook C along the axis X during latching. To this end, the first and second collars 11.5', 11.6' comprise frustoconical outer surfaces 11.7', 11.8' defining guide bevels capable of engaging the hook between a first shoulder 11.3' and a second shoulder 11.4' separated by a distance D slightly greater than the width of the hook, so as to form a functional gap. The outer surfaces 11.7', 11.8' converge towards the axis X.
[0045] Therefore, even under harsh usage conditions, the sliding between the threaded nut 11' and the hook C is still limited to the functional gap, which limits the abrasive wear of the convex surface 11.1' of the threaded nut 11' and / or the latching surface of the hook C, and ensures a precise contact area between the threaded nut 11' and the hook C.
[0046] It goes without saying that the invention is not limited to the embodiments described, but covers any variant coming within the ambit of the invention as defined by the claims.
[0047] The first spring 18 . 1 and the second spring 18 . 2 may be replaced by any elastic return means (wave springs, stacks of Belleville washers, etc.) capable of returning the threaded nut 11 , 11 ′ to its equilibrium position.
[0048] If the lengths of the first spring 18.1 and the second spring 18.2 are different, the number or thickness of the friction washers can be adapted according to the centering requirements of the threaded nuts 11, 11'. Generally, any adjustment means can be used to ensure centering of the threaded nuts 11, 11', if necessary.
[0049] Although it is advantageous to provide friction washers 20 between the threaded nuts 11 , 11 ′ and each ring 19 and between each ring 19 and each ring 13 , it is also feasible to provide friction washers 20 only between the threaded nuts 11 , 11 ′ and the ring 19 or between the ring 19 and the ring 13 .
[0050] Rings 13, 19 are optional.
[0051] The apparatus 10, 10' may include ball bearings, rollers or needles to facilitate rotation of the threaded nut 11 relative to the collet member.
[0052] Although the elastic return means of the device 10 , 10 ′ comprise here two springs 18 . 1 , 18 . 2 , they may also comprise only one.
[0053] Although the shoulders 11.3', 11.4' are here arranged to bear against the flanks of the hook C in order to center the threaded nut 11' relative to said hook C, they may also be carried on any other part of the attachment housing B, for example on the sole of a housing fixed to the attachment housing B.
[0054] The apparatus 10, 10' may be fixed directly to the door T or may be offset by a connecting rod assembly.
[0055] Although the device 10 , 10 ′ is attached to the door T here, it can also be machined directly on the door T.
[0056] Although the device 10 , 10 ′ is attached here to the door T, it could also be attached to the landing gear L.
[0057] In general, the device 10 , 10 ′ may be attached to any door of the aircraft A (emergency generator door, access door, cargo door, etc.).
[0058] In a more general manner, the device 10 , 10 ′ may be attached to any movable element of an aircraft (structural element, slats, flaps, air brakes, etc.).
[0059] The bolt formed by the screw 15 and the nut 16 may be replaced by any element capable of retaining the shaft 12 between the first cheek 14 . 1 and the second cheek 14 . 2 of the collet 14 .
[0060] The first and second loops 11.5', 11.6' may have shapes different from those described above, in particular any shape defining a guide slope enabling the hook to engage between the first and second shoulders 11.3', 11.4'.
Claims
1. A device (10, 10') for latching a movable element (T) by means of a hook (C), comprising a threaded nut (11, 11') movably mounted on a shaft (12), translating along the longitudinal axis (X) of the shaft between two extreme positions and returning to a rest position arranged between the two extreme positions by means of elastic return means (18.1, 18.2), the olive also being movably mounted on the shaft (12), rotating about the longitudinal axis of the shaft.
2. The device (10, 10') according to claim 1, characterized in that It comprises a collet (14) intended to be attached to the movable element (T), said collet comprising two cheeks (14.1, 14.2), each bearing one end (12.1, 12.2) of the shaft (12), and between which the threaded nut (11, 11') extends.
3. The device according to claim 2, characterized in that The elastic return means comprises at least one helical spring (18.1, 18.2) extending between the threaded nut (11, 11') and one of the cheeks (14.1, 14.2) of the collet piece (14).
4. The device according to claim 3, characterized in that The ends of the springs (18.1, 18.2) are each mounted on a guide ring (19) which is slidingly mounted on the shaft (12), the guide ring being arranged to ensure that the springs are guided without contact with the shaft.
5. The device (10, 10') according to claim 3, characterized in that The elastic return means comprises a first helical spring (18.1) extending between one of the cheeks (14.1) and the threaded nut (11, 11'), and a second helical spring (18.2) extending between the other of the cheeks (14.2) and the threaded nut (11, 11').
6. The device (10') according to any one of the preceding claims, characterized in that The threaded nut comprises a body including an outer surface defined by a first shoulder (11.3') and a second shoulder (11.4'), the first shoulder and the second shoulder jointly defining a receiving area for the hook.
7. The device (10') according to claim 6, characterized in that The body comprises a first collar (11.5') and a second collar (11.6') forming the first shoulder (11.3') and the second shoulder (11.4') respectively, the first collar and the second collar each comprising a frustoconical outer surface (11.7', 11.8') to form a guide ramp enabling the hook to engage between the first shoulder and the second shoulder.
8. An aircraft door (T) equipped with a device (10, 10') according to any one of claims 1 to 7.
9. Aircraft landing gear (L) equipped with a device (10, 10') according to any one of claims 1 to 7.
10. Aircraft (A) comprising at least one door according to claim 8 or at least one landing gear according to claim 9, said hook being fixed to a structure (S) of said aircraft.