A front landing gear head lock pin mechanism

Abstract

The application provides a front landing gear head lock pin mechanism, which comprises a landing gear head, a lock pin and a spring, the top end of the landing gear head is provided with a hole capable of inserting the lock pin, the bottom of the hole is provided with a first spring seat, the bottom of the lock pin is provided with a second spring seat, and the spring is installed between the first spring seat and the second spring seat; the middle of the lock pin is provided with a slot, the top of the slot is hingedly connected with a first connecting rod, the side of the landing gear head is provided with a locking slot, the locking slot is arranged along the axis direction of the lock pin, a push rod is movably arranged in the locking slot, the push rod is connected with a second connecting rod, the second connecting rod is hingedly connected with the bottom of the first connecting rod through the side wall of the landing gear head, and a limiting structure is arranged at the hinge connection position of the second connecting rod and the first connecting rod. The front landing gear head lock pin mechanism provided by the application has a complete circular shaft surface as the force bearing surface of the screw pile to bear the shearing force, has no stress concentration point and bending moment, has no risk of jamming in the working process, and the working safety coefficient of the landing gear is improved.

Description

Technical Field

[0001] This invention belongs to the field of locking pin technology, and specifically relates to a locking pin mechanism for the nose landing gear head. Background Technology

[0002] In existing technology, the nose landing gear is locked by a locking pin mechanism at the nose landing gear head. This mechanism works in conjunction with a locking groove mechanism on the aircraft to lock the nose landing gear in the retracted or extended position. Currently, the locking pin mechanism used on aircraft employs a circular shaft as a stud to extend and retract the locking pin. A threaded hole is drilled in the central circular section of the stud, connecting it to a connecting rod. This connection method suffers from a small stress concentration area at the stud connection point, where both shear force and bending moment exist simultaneously. Consequently, cracks in the threaded hole at the stud-connecting rod connection point are frequent on certain aircraft models. The main cause is that the connection point cracks due to bending moment. If these cracks are not detected and addressed promptly, they can lead to flight accidents. For example, there have been serious accidents where the nose landing gear could not be lowered due to stud breakage. Therefore, to solve these problems, it is necessary to research and develop a landing gear head locking pin mechanism that can reduce or minimize stress at the connection point. Summary of the Invention

[0003] A front landing gear head locking pin mechanism reduces the risk of bolt breakage by increasing the stress-bearing area at the connection between the bolt and the connecting rod and eliminating stress concentration points.

[0004] A nose landing gear head locking mechanism includes a landing gear head, a locking pin, and a spring. The landing gear head has an opening at its top, a first spring seat at the bottom of the opening, and a second spring seat at the bottom of the locking pin. The spring is then installed between the first and second spring seats, allowing the locking pin to insert into the landing gear opening. To control the locking pin, a slot is cut in the middle of the locking pin, and a first connecting rod is hinged to the top of the slot. A locking groove aligned with the axis of the locking pin is formed on the side of the landing gear head. A lever is movably mounted within the locking groove, and a second connecting rod is connected to the lever. The second connecting rod passes through the side wall of the landing gear head and is hinged to the bottom of the first connecting rod. A limiting structure is provided at the hinge point. These features control the locking pin.

[0005] In the above structure, the function of the limiting structure is to allow the first link and the second link to bend inward only through the hinge, so as to achieve that the automatic retraction and pull retraction of the locking pin do not interfere with each other. Specifically, the limiting structure consists of a first stop protrusion on the first link and a second stop protrusion on the second link, and the first stop protrusion and the second stop protrusion can block each other.

[0006] The first connecting rod consists of three parts: a stud, a sleeve, and a rod. The stud passes through the locking pin and is rotatably connected to the locking pin. The sleeve is connected to the middle of the stud. The top of the rod is threadedly connected to the sleeve. The first stop protrusion is located at the bottom of the rod. The second connecting rod and the rod are hinged together by a connecting shaft. This structure allows the length of the first connecting rod to be adjusted, thereby controlling the length of the locking pin retracting and extending.

[0007] To reduce the structural complexity of the locking pin, the connection method of the stud is optimized. Two protrusions are provided on the side of the stud along the axis of the stud, with a gap between the two protrusions. Then, a through hole is provided on the threaded sleeve for the stud and the protrusions to pass through, so that the gap between the two protrusions is located inside the threaded sleeve. A limiting hole is then opened on the threaded sleeve, corresponding to the position of the protrusion gap. A limiting bolt is inserted into the limiting hole for fixation. This structural design allows the stud to be fixed in position using only the protrusions, without the need for other structures on the locking pin.

[0008] The nose landing gear head locking pin mechanism provided by this invention has a complete circular shaft surface on which the bolt bears shear force, with no stress concentration points and no bending moment, eliminating the risk of jamming during operation and improving the safety factor of the landing gear. Attached Figure Description

[0009] The present invention will now be described in further detail with reference to the accompanying drawings:

[0010] Figure 1 This is an exploded view of the structure of the present invention;

[0011] Figure 2 This is a schematic diagram of the front structure of the present invention;

[0012] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure dissected along the CC line;

[0013] Figure 4 for Figure 3 Schematic diagram of part A in the middle;

[0014] Figure 5 for Figure 3 Schematic diagram of Part B in the middle section;

[0015] Figure 6 for Figure 4 A schematic diagram of the cross-sectional structure dissected along the DD line;

[0016] Wherein: 1-Landing gear head; 2-Locking pin; 3-Spring; 4-First spring seat; 5-Second spring seat; 6-First connecting rod; 7-Second connecting rod; 8-Locking groove; 9-Lever; 10-First stop protrusion; 11-Second stop protrusion; 61-Screw post; 62-Screw sleeve; 63-Screw rod; 64-Connecting shaft; 65-Protrusion; 66-Limiting hole; 67-Limiting bolt. Detailed Implementation

[0017] To further illustrate the concept of this invention, specific embodiments will be provided below for detailed explanation. These embodiments are merely illustrative and explanatory and should not be construed as limiting the scope of protection of this invention. All technologies implemented based on the content of this invention are covered within the scope of protection intended by this invention.

[0018] like Figure 1-3 The diagram shows a nose landing gear head locking mechanism. The entire locking mechanism is located inside the landing gear head 1. The locking pin 2 is installed in a hole in the landing gear head 1. A first spring seat 4 is installed at the bottom of the hole in the landing gear head 1, and a second spring seat 5 is installed at the bottom of the locking pin 2. A spring 3 is installed between the first spring seat 4 and the second spring seat 5. A groove is opened in the middle part of the locking pin 2. A locking groove 8 is opened in the landing gear head 1. The locking groove 8 is located on one side of the locking pin 2. A groove is opened on the side wall of the landing gear head 1 facing the locking groove 8. A lever 9 that can move up and down is installed in the locking groove 8. The locking pin 2 and the lever 9 are connected by a first connecting rod 6 and a second connecting rod 7 passing through the groove on the side wall of the landing gear.

[0019] The first connecting rod 6 consists of a stud 61, a sleeve 62, and a screw 63. A hole is drilled in the locking pin 2 for the stud 61 to pass through. Two protrusions 65 are provided on the side of the stud 61, with a gap between them. The sleeve 62 has a through hole for the stud 61 and the protrusions 65 to pass through. The sleeve 62 fits onto the stud 61 through the through hole. A limiting hole 66 is drilled at a position corresponding to the gap between the sleeve 62 and the protrusions 65. A limiting bolt 67 is inserted into the limiting hole 66 and engaged within the gap between the protrusions 65, thus fixing the position of the sleeve 62. Figure 4 , Figure 6 As shown. The upper half of the screw 63 is threaded, and the bottom of the screw sleeve 62 has a threaded hole. The screw 63 is inserted into the threaded hole of the screw sleeve 62 through the thread. The bottom of the second connecting rod 7 has a hole, through which it is fitted onto the lever 9. The second connecting rod 7 and the screw 63 are hinged, and the hinged part is fixed by the connecting shaft 64. The screw 63 has a first stop protrusion 10, and the second connecting rod 7 has a second stop protrusion 11. The two first stop protrusions 10 and the second stop protrusion 11 are located at the hinged position, and the first stop protrusion 10 is located on the inner part, as shown. Figure 5 As shown.

[0020] The working principle is as follows: The landing gear retraction actuator is connected to the lever 9. When unlocking, the actuator pulls the lever 9 downward, and the lever 9 moves downward along the locking groove 8. At the same time, it pulls the second connecting rod 7. During the downward movement of the second connecting rod 7, the first stop protrusion 10 and the second stop protrusion 11 block each other, so that the hinge of the second connecting rod 7 and the screw 63 cannot rotate. This pulls the screw 63 downward, and the linkage sleeve 62 and the screw post 61 move downward, pulling the locking pin 2 back into the landing gear head 1, thus unlocking. When locked, the actuator pushes and pulls the landing gear to the locked position through the extension and retraction action. When the locking pin 2 contacts the locking groove structure on the aircraft, it is compressed back into the landing gear head 1. During the retraction of the locking pin 2, the locking pin 2 drives the stud 61, the sleeve 62 and the screw 63 to move downward. Due to the position setting of the first stop protrusion 10 and the second stop protrusion 11, when the screw 63 moves downward, it will make the first stop protrusion 10 and the second stop protrusion 11 move away from each other, allowing the hinge to rotate freely. The downward movement of the screw 63 will only cause the second connecting rod 7 to rotate around the lever 9, and will not produce an overall downward movement trend, thereby avoiding the locking pin 2 retraction from disturbing the lever 9. When the landing gear moves to the locked position, the locking pin 2 is pushed into the locking groove under the action of the spring 3, realizing the locking of the landing gear.

[0021] During use, if the extension length of the locking pin 2 needs to be adjusted, the screw 63 can be rotated to adjust the overall length of the screw 63 and the sleeve 62, thereby controlling the extension length of the locking pin 2. During manufacturing, the width of the sleeve 62 can be machined to match the width of the slot in the middle of the locking pin 2, preventing the sleeve 62 from shifting left or right during use. Additionally, safety wires can be added when fixing components such as the lever 9, limit bolt 67, and connecting shaft 64 to prevent them from falling off during use. Throughout the entire operation, the screw post 61 only needs to withstand downward tension, elasticity, and friction; there are no stress concentration points, and it does not need to withstand bending moments, avoiding the possibility of cracks in the screw post 61. Furthermore, since the connections between components are primarily hinged, there is no risk of jamming, greatly improving the safety factor.

[0022] There are many methods and approaches that can realize the technical solution of this invention, and the above are merely preferred embodiments provided by way of example. Those skilled in the art can conceive of many modifications, alterations, and substitutions without departing from this invention. It should be understood that various alternatives to the embodiments of this invention described herein can be employed in the practice of this invention. The appended claims are intended to define the scope of this invention and therefore cover the methods within the scope of these claims and their equivalents. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

Claims

1. A nose landing gear head locking pin mechanism, characterized in that: The system includes a landing gear head (1), a locking pin (2), and a spring (3). The landing gear head (1) has a hole at the top that can be inserted into the locking pin (2). A first spring seat (4) is provided at the bottom of the hole, and a second spring seat (5) is provided at the bottom of the locking pin (2). The spring (3) is installed between the first spring seat (4) and the second spring seat (5). The locking pin (2) has a slot in the middle. A first connecting rod (6) is hinged to the top of the slot. A locking groove (8) is provided on the side of the landing gear head (1) located on the locking pin (2). The locking groove (8) is set along the axis of the locking pin (2). A lever (9) is movably set in the locking groove (8). A second connecting rod (7) is connected to the lever (9). The second connecting rod (7) passes through the side wall of the landing gear head (1) and is hinged to the bottom of the first connecting rod (6). A limit structure is provided at the hinge of the second connecting rod (7) and the first connecting rod (6). The limiting structure is a first stop protrusion (10) on the first link (6) and a second stop protrusion (11) on the second link (7). The first stop protrusion (10) and the second stop protrusion (11) cooperate with each other so that the hinge of the first link (6) and the second link (7) can only be bent inward. The first connecting rod (6) includes a stud (61), a sleeve (62) and a screw (63). The stud (61) passes through the locking pin (2) and is rotatably connected to the locking pin (2). The sleeve (62) is connected to the middle of the stud (61). The top of the screw (63) is connected to the sleeve (62) by a thread. The first stop protrusion (10) is provided at the bottom of the screw (63). The second connecting rod (7) and the screw (63) are hinged by a connecting shaft (64).

2. The nose landing gear head locking pin mechanism according to claim 1, characterized in that... The screw post (61) has two protrusions (65) on its side. The protrusions (65) are arranged along the axis of the screw post (61) and there is a gap between the two protrusions (65). The screw sleeve (62) has a through hole for the screw post (61) and the protrusions (65) to pass through. When the screw sleeve (62) and the screw post (61) are assembled, the gap between the two protrusions (65) is located inside the screw sleeve (62). The screw sleeve (62) has a limit hole (66) which corresponds to the gap between the protrusions (65). The screw sleeve (62) is connected to the screw post (61) by a limit bolt (67) that matches the limit hole (66).

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