An advanced helicopter tail door system

Abstract

The present invention relates to the technical field of helicopter cabin doors, and specifically relates to an advanced helicopter tail cabin door system, which includes an upper cabin door assembly and a lower cabin door assembly respectively connected to the helicopter airframe. The upper cabin door assembly includes an upper door body, and an upper actuator assembly, an upper hinge assembly, an upper locking assembly and a jettisoning assembly are arranged on the upper cabin door assembly. The lower cabin door assembly includes a lower door body, and a lower actuator assembly, a lower hinge assembly, a lower locking assembly, a lower sealing assembly, a horizontal opening limit assembly, a cushion block assembly and a gangplank assembly are arranged on the lower cabin door assembly. The present invention jointly solves the design problems of the retraction and deployment of the helicopter tail cabin door, multi-lock linkage, freight system, emergency jettisoning device, door body support structure integration, etc. through components such as the cabin door structure and the door lock mechanism.

Description

Technical Field

[0001] The invention relates to the technical field of helicopter cabin doors, and in particular to an advanced helicopter tail cabin door system. Background Art

[0002] In the existing field of helicopter doors, the tail door is usually an integrated mechanism that rotates to open. Due to factors such as the structural design of the helicopter, the tail door is very inconvenient to use. It is not only slow to open, but also has a relatively simple function. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides an advanced helicopter tail door system. The technical problem to be solved is how to design a helicopter tail door system that is easy to operate and has high safety and integrates the functions of retracting, door body, cargo transportation, emergency ejection, etc.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is: an advanced helicopter tail door system, characterized in that: it comprises an upper door assembly and a lower door assembly respectively connected to the helicopter body, the bottom end of the upper door assembly is sealed and connected to the top end of the lower door assembly, the upper door assembly comprises an upper door body, the upper door assembly is provided with an upper actuator assembly, an upper hinge assembly, an upper locking assembly and a jettisoning assembly, the lower door assembly comprises a lower door body, the lower door assembly is provided with a lower actuator assembly, a lower hinge assembly, a lower locking assembly, a lower sealing assembly, a horizontal opening limit assembly, a cushion block assembly and a springboard assembly;

[0005] The upper actuator assembly includes an upper actuator arranged on the inner side of the upper door body and located on both sides of the upper door body, and the upper actuator is transmission-connected with an electromagnetic valve. The lower actuator assembly includes a lower actuator arranged on the inner side of the lower door body and located on both sides of the lower door body, and the lower actuator is also transmission-connected with an electromagnetic valve. The upper actuator is transmission-connected with the upper locking assembly, and the lower actuator is transmission-connected with the lower locking assembly.

[0006] Furthermore, the upper hinge assembly includes an upper tailgate side hinge arranged on the inner side of the upper door body, one end of the upper tailgate side hinge is fixedly connected to the upper door body, the other end of the upper tailgate side hinge is rotatably connected to the fuselage side hinge through a first axle pin, the fuselage side hinge is fixedly connected to the helicopter body, and a limiting boss is also arranged at the other end of the upper tailgate side hinge, which matches the fuselage side hinge.

[0007] Furthermore, the upper locking assembly includes servo motors arranged on both sides of the upper door body and located on the inner side of the upper door body, each servo motor is respectively connected to a connecting rod mechanism, and one end of the two connecting rod mechanisms is commonly connected to a latch lock.

[0008] Further, the upward throwing and releasing assembly includes a glass disposed at the bottom end of the upper door body. An embedded rubber strip is hermetically arranged between the glass and the upper door body. Throwing and releasing ribbons are respectively arranged on the inner and outer sides of the upper door body, and the two throwing and releasing ribbons are fixedly connected to the embedded rubber strip respectively.

[0009] Further, the horizontal opening limiting assembly includes horizontal mooring rings disposed on both sides of the lower door body and on the inner side of the lower door body. A horizontal mooring steel cable is fixedly connected to the horizontal mooring ring. The bottom end of the horizontal mooring steel cable is clamped in the horizontal mooring ring, and the top end of the horizontal mooring steel cable is fixedly connected to the helicopter body.

[0010] Further, the cushion block assembly includes two rubber blocks disposed on both sides of the lower door body and near the top end of the lower door body. The rubber blocks are located on the outer side of the lower door body, and the rubber blocks are fixedly connected to the cross beam and longitudinal beam of the lower door body through bolts.

[0011] Further, the lower locking assembly includes lock catch seats disposed on both sides of the lower door body and on the inner side of the lower door body. The lock catch seats are matched with the locks on the helicopter body.

[0012] Further, the gangplank assembly includes a gangplank mounting seat installed at the top end of the lower door body. A second pin is inserted into the gangplank mounting seat. A pin retaining plate is arranged on the second pin. The second pin is fixedly connected to a gangplank. One end of the gangplank is rotatably arranged on the lower door body through the second pin, and the other end of the gangplank is fixedly connected to the inner side surface of the lower door body through a pull rod. Both ends of the pull rod are movably and fixedly connected to the gangplank and the lower door body through a third pin.

[0013] Further, the lower hinge assembly includes a lower tail door side hinge mounting seat disposed at the bottom end of the lower door body. A fuselage side hinge mounting seat is rotatably connected to the lower tail door side hinge mounting seat through a rotating shaft. A hinge mounting reinforcement plate is further arranged between the lower tail door side hinge mounting seat and the lower door body.

[0014] The beneficial effects brought by this technical solution are as follows: For an advanced helicopter tail door system of the present invention, through components such as the door structure, door lock mechanism, etc., design problems such as the retraction and deployment of the helicopter tail door, multi-lock linkage, freight system, emergency throwing and releasing device, and integration of the door body support structure are jointly solved. Among them, the gangplank assembly can form a boarding passage for vehicles to get on and off the helicopter. After the lower door body is opened, its bottom plate can be kept horizontal through the cushion block assembly, which is convenient for cargo transportation and aerial material delivery, etc. The lower sealing assembly provides a reliable closed environment for the whole door, ensuring the safety of the helicopter and the crew on board during flight. The throwing and releasing mechanism can provide an evacuation passage for the crew in an emergency state. The upper locking assembly and the lower locking assembly can realize the position locking function of the upper and lower hatches. Description of the Drawings

[0015] The accompanying drawings are used to provide a further understanding of the present invention and form a part of the specification. They are used, together with the embodiments of the present invention, to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0016] Figure 1 is a schematic structural diagram of an advanced helicopter tail door system of the present invention in an embodiment;

[0017] Figure 2 is another schematic structural diagram of an advanced helicopter tail door system of the present invention in an embodiment;

[0018] Figure 3 is yet another schematic structural diagram of an advanced helicopter tail door system of the present invention in an embodiment;

[0019] Figure 4 is Figure 1 a schematic structural diagram of the structure at I in;

[0020] Figure 5 is a schematic structural diagram of the locking assembly of an advanced helicopter tail door system of the present invention in an embodiment;

[0021] Figure 6 is Figure 1 a schematic structural diagram of the structure at II in;

[0022] Figure 7 is a cross-sectional schematic diagram of the ejection mechanism of an advanced helicopter tail door system of the present invention in an embodiment;

[0023] Figure 8 is a schematic structural diagram of the horizontal opening limit assembly of an advanced helicopter tail door system of the present invention in an embodiment;

[0024] Figure 9 is a schematic structural diagram of the spacer assembly of an advanced helicopter tail door system of the present invention in an embodiment;

[0025] Figure 10 is Figure 1 a schematic structural diagram of the structure at III in;

[0026] Figure 11 is a schematic structural diagram of the second pin of an advanced helicopter tail door system of the present invention in an embodiment;

[0027] Figure 12 is Figure 2 a schematic structural diagram of the structure at IV in;

[0028] In the figure: 1 - upper hatch assembly, 2 - lower hatch assembly, 11 - upper door body, 12 - upper actuator assembly, 13 - upper hinge assembly, 14 - upper locking assembly, 15 - jettisoning assembly, 21 - lower door body, 22 - lower actuator assembly, 23 - lower hinge assembly, 24 - lower locking assembly, 25 - lower sealing assembly, 27 - horizontal opening limit assembly, 28 - cushion block assembly, 29 - gangplank assembly, 121 - upper actuator, 221 - lower actuator, 31 - upper tail door side hinge, 132 - first pin, 133 - fuselage side hinge, 141 - servo motor, 142 - linkage mechanism, 143 - bolt lock, 151 - glass, 152 - embedded rubber strip, 153 - jettisoning ribbon, 271 - horizontal mooring ring, 272 - horizontal mooring cable, 281 - rubber block, 282 - bolt, 241 - lock catch seat, 291 - gangplank mounting seat, 292 - second pin, 293 - pin retaining plate, 294 - gangplank, 295 - tie rod, 296 - third pin, 231 - lower tail door side hinge mounting seat, 232 - fuselage side hinge mounting seat, 233 - hinge mounting reinforcement plate. Detailed implementation mode

[0029] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0030] As Figures 1 to 12 shown, this advanced helicopter tail hatch system includes an upper hatch assembly 1 and a lower hatch assembly 2 respectively connected to the helicopter fuselage. The bottom end of the upper hatch assembly 1 is hermetically connected to the top end of the lower hatch assembly 2. The upper hatch assembly 1 includes an upper door body 11. An upper actuator assembly 12, an upper hinge assembly 13, an upper locking assembly 14 and a jettisoning assembly 15 are provided on the upper hatch assembly 1. The lower hatch assembly 2 includes a lower door body 21. A lower actuator assembly 22, a lower hinge assembly 23, a lower locking assembly 24, a lower sealing assembly 25, a horizontal opening limit assembly 27, a cushion block assembly 82 and a gangplank assembly 29 are provided on the lower hatch assembly 2.

[0031] Among them, the upper actuator assembly 12 includes upper actuators 121 disposed inside the upper door body 11 and on both sides of the upper door body 11. The upper actuators 121 are drivingly connected to solenoid valves. The lower actuator assembly 22 includes lower actuators 221 disposed inside the lower door body 21 and on both sides of the lower door body 21. The lower actuators 221 are also drivingly connected to solenoid valves. The upper actuators 121 are drivingly connected to the upper locking assembly 14, and the lower actuators 221 are drivingly connected to the lower locking assembly 24. In this way, by controlling the upper actuators 121 and the lower actuators 221 respectively through the solenoid valves, the upper door body 11 and the lower door body 21 can be driven to move while the upper locking assembly 14 and the lower locking assembly 24 are opened, thereby realizing the opening and closing of the upper and lower hatch doors. The upper hinge assembly 13 is used to fix the upper door body 11 to the helicopter body. The ejection assembly 15 is used for escape in case of emergency. The lower hinge assembly 23 is used to fix the lower door body 21 to the helicopter body. The lower sealing assembly 25 includes a sealing strip disposed around the lower door body 21, which is used to ensure the overall sealing when the upper and lower hatch doors are closed. The horizontal opening limit assembly 27 can improve the load capacity when the lower door body 21 is in the horizontal position, improving the stability. The spacer block assembly 28 is used to support the lower door body 21 from the outside when the lower door body 21 is opened to prevent damage to its surface. The gangplank assembly 29 is used for the vehicle to get on and off the plane when the lower door body 21 is opened.

[0032] In this embodiment, the upper hinge assembly 13 includes an upper tail door side hinge 131 disposed on the inner side of the upper door body 11. One end of the upper tail door side hinge 131 is fixedly connected to the upper door body 11, and the other end of the upper tail door side hinge 131 is rotatably connected to a fuselage side hinge 133 through a first pin 132. The fuselage side hinge 133 is fixedly connected to the helicopter body. A limit boss 134 is further disposed at the other end of the upper tail door side hinge 131, and the limit boss 134 is matched with the fuselage side hinge 133. In this way, when the upper actuator 121 works, the upper door body 11 can rotate relative to the helicopter fuselage through the first pin 132, thereby realizing the opening of the upper door body 11. The limit boss 134 can play a limiting role. Considering the installation accuracy of the actuator, the limiting angle of the hinge is 30° + 2°. Therefore, when the upper door body 11 is opened inward to 32°, the limit boss 134 will overlap with the fuselage side hinge 133, thereby preventing the upper door body 11 from opening further.

[0033] In this embodiment, the upper locking assembly 14 includes servo motors 141 disposed on both sides of the upper door body 11 and inside the upper door body 11. Each servo motor 141 is respectively drivingly connected to a link mechanism 142. One ends of the two link mechanisms 142 are commonly connected to a bolt lock 143. In this way, when it is necessary to open the upper door body 11, only need to drive the servo motor 141 to rotate clockwise first, drive the link mechanism 142 to pull the lock core of the bolt lock 143, and the upper door body 11 can be opened.

[0034] In this embodiment, the upward throwing and releasing assembly 15 includes a glass 151 disposed at the bottom end of the upper door body 11. An embedded rubber strip 152 is hermetically arranged between the glass 151 and the upper door body 11. Throwing and releasing ribbons 153 are respectively arranged on the inner and outer sides of the upper door body 11. The two throwing and releasing ribbons 153 are fixedly connected to the embedded rubber strip 152 respectively. In this way, when throwing and releasing is required in case of an emergency, only by pulling the throwing and releasing ribbon 153 on the inner or outer side of the upper door body 11, the embedded rubber strip 152 can be disengaged from between the glass 151 and the door body 11, and then the glass 151 can be pushed out to achieve throwing and releasing.

[0035] In this embodiment, the horizontal opening limiting assembly 27 includes horizontal mooring rings 271 disposed on both sides of the lower door body 21 and located inside the lower door body 21. A horizontal mooring cable 272 is fixedly connected to the horizontal mooring ring 271. The bottom end of the horizontal mooring cable 272 is clamped inside the horizontal mooring ring 271, and the top end of the horizontal mooring cable 272 is fixedly connected to the helicopter body. In this way, when the lower door body 21 is in a horizontal position, since there will be personnel standing during aerial material delivery, the horizontal opening limiting assembly 27 can prevent the lower actuator assembly 22 from losing pressure and causing the lower door body 21 to fail to maintain the horizontal position. The fixed connection between the horizontal mooring cable 272 and the horizontal mooring ring 271 can further improve the stability of the lower door body 21 after opening and prevent the lower actuator assembly 22 from losing pressure and causing the lower door body 21 to fail to maintain the horizontal position.

[0036] In this embodiment, the cushion block assembly 28 includes two rubber blocks 281 disposed on both sides of the lower door body 21 and near the top end of the lower door body 21. The rubber blocks 281 are located on the outer side of the lower door body 21. The rubber blocks 281 are fixedly connected to the cross beam and longitudinal beam of the lower door body 21 by bolts 282. In this way, by arranging the two rubber blocks 281 at the top edge of the left and right sides of the lower door body 21 respectively, the bottom surface can be supported after the lower door body 21 is opened, preventing the lower door body 21 from directly contacting the bottom surface and damaging the hatch. Since the load at the connection between the rubber block 281 and the lower door body 21 is large, the screwing connection method can be more reliable and stable.

[0037] In this embodiment, the lower locking assembly 24 includes latch seats 241 disposed on both sides of the lower door body 21 and inside the lower door body 21. The latch seats 241 are matched with the lock body on the helicopter fuselage, so that the lower door body 21 can be locked by connecting and fixing the lock body with the latch seats 241. The specific working principle is as follows: The lower locking assembly 24 further includes a lock box, a lock pin, a lock hook, a lever, a swing arm and a microswitch. When the actuator operates, the swing arm rotates to drive the lock hook to rotate and reset, and the door lock is opened. At the same time, the lock hook is separated from the microswitch, and the microswitch feeds an electrical signal back to the hydraulic retraction and extension system controller to indicate that this lock has been opened. When closing, the actuator operates, the lock pin contacts the lock hook, drives the lock hook to rotate, the swing arm resets, and the door lock is closed. At the same time, the lock hook and the microswitch are combined, and the microswitch feeds an electrical signal back to the hydraulic retraction and extension system controller to indicate that this lock has been closed. In the case of power-off and pressure-off of the lower door body 21, a manual opening handle can be designed on the right side inside the fuselage. Rotating the handle and pulling the cable can drive the swing arm to rotate, thereby opening the door lock, and further improving the safety performance, so that the lower door body 21 can be opened even in the case of power-off and pressure-off.

[0038] In this embodiment, the gangplank assembly 29 includes a gangplank mounting seat 291 installed at the top end of the lower door body 21. A second pin 292 is inserted through the gangplank mounting seat 291. A pin retaining plate 293 is arranged on the second pin 292. The second pin 292 is fixedly connected to a gangplank 294. One end of the gangplank 294 is rotatably arranged on the lower door body 21 through the second pin 292, and the other end is fixedly connected to the inner side surface of the lower door body 21 through a pull rod 295. Both ends of the pull rod 295 are movably and fixedly connected to the gangplank 294 and the lower door body 21 through a third pin 296. In this way, the gangplank assembly 29 can meet the needs of vehicles getting on and off the helicopter. At the same time, the distance between the gangplanks 294 is also closely related to the wheel width and wheelbase of the vehicle. Currently, the maximum wheel width of the loadable vehicle is 310 mm, and the minimum wheelbase is 1286 mm. Also, considering a left offset of 150 mm when getting on the vehicle and leaving enough space of 50 mm on one side for getting on the vehicle, according to the principle of left-right symmetry design, the distance between the left and right gangplanks 294 is 676 mm. Considering the minimum wheel width of the loadable vehicle is 305 mm and the maximum wheelbase is 1385 m, the maximum distance between the left and right gangplanks is 2095 mm. Therefore, by designing the width of the gangplank 294 to be 709.5 mm, it can meet the access requirements of all input vehicles. Structurally, the flipping of the gangplank 294 is achieved through the second pin 292, and the fixation between the gangplank 294 and the lower door body 21 is achieved through the third pin 296. When there is a need for vehicle access and egress, the lower door body 21 is opened, the second pin 292 is inserted to fix the gangplank 294 to the gangplank mounting seat 291, and the gangplank 294 is rotated. When the hatch needs to be closed, the gangplank 294 is rotated, and the third pin 296 is inserted to fix the gangplank 294 to the lower door body 21. It is also possible to use a movable pin to control the length of the pull rod between the gangplank 294 and the lower door body 21.

[0039] In this embodiment, the lower hinge assembly 23 includes a lower tailgate side hinge mounting seat 231 arranged at the bottom end of the lower door body 21. A fuselage side hinge mounting seat 232 is rotatably connected to the lower tailgate side hinge mounting seat 231 through a rotating shaft. A hinge mounting reinforcement plate 233 is also arranged between the lower tailgate side hinge mounting seat 231 and the lower door body 21, thereby realizing the rotational opening and closing of the lower door body 21.

[0040] In summary, the present invention provides an advanced helicopter tail door system, which solves the design problems of retracting and extending the helicopter tail door, multi-lock linkage, cargo system, emergency jettisoning device, door support structure integration, etc. through the door structure, door lock mechanism and other components. Among them, the springboard assembly can form a boarding passage for vehicles to get on and off the helicopter. After the lower door body is opened, the bottom plate can be kept horizontal by the pad assembly, which is convenient for cargo transportation and dropping of materials in the air. The lower sealing assembly 25 provides a reliable closed environment for the entire door, ensuring the safety of the helicopter and the personnel on board during flight. The jettisoning mechanism can provide an evacuation passage for the personnel on board in an emergency state. The upper locking assembly and the lower locking assembly can realize the position locking function of the upper and lower doors.

[0041] The working modes of the helicopter tail door system are divided into normal working mode and emergency working mode. The workflow of each working mode is as follows:

[0042] 1) Normal working mode:

[0043] 1. The operator controls the system on the freight floor to power on the system. After the system is powered on, it automatically performs a power-on self-test. After the self-test is completed, if there is no fault, it enters the normal working mode;

[0044] 2. The upper door body and the lower door body are opened to the fully open state at the same time - press the simultaneous opening button, the solenoid valve is activated, the upper locking component and the lower locking component are opened, and the feedback signal is sent. After receiving the unlocking signal, the control system re-sends the action command to the solenoid valve, the upper actuator is retracted, the upper door body is opened, the lower actuator is extended, and the lower door body is opened. After opening to the full extent, the built-in hydraulic micro switch of the upper actuator cylinder and the lower door body position signal sensor feedback the full extent signal, and the upper and lower door bodies stop moving;

[0045] 3. The lower door body opens to the fully open state alone - press the lower opening button, the solenoid valve is activated, the lower locking component opens, and the feedback signal is sent. After the control system receives the unlocking signal, it sends an action command to the solenoid valve again, the lower actuator extends, and the lower door body opens. After it is fully opened, the WeChat signal is fed back and the lower door body stops moving;

[0046] 4. The upper door is fully opened and the lower door is opened to the neutral state - select the neutral working mode, press the open button, the solenoid valve is activated, the upper locking component and the lower locking component are opened, and the feedback signal is sent. After receiving the signal, the control system sends an action command to the solenoid valve. After the upper door is fully opened, the feedback signal is sent back, and the upper door stops moving. After the lower door reaches the neutral position, the feedback signal is sent back, and the lower door stops moving;

[0047] 5. Open the lower door body alone to the neutral state - Scratch the pull rope of the lower door body, select the neutral working mode, press the lower open button, the solenoid valve acts, the lower locking component opens, feedback signal. After the control system receives the signal, it issues an action instruction to the solenoid valve, the lower actuator extends, the lower door body opens. After the lower door body reaches the neutral position, it feeds back the in-place signal and the lower door body stops moving;

[0048] 6. Close the upper door body and the lower door body simultaneously - Press the simultaneous close button, detect the hatch door. Retract the strut lock pin at the neutral position. At the same time, the solenoid valve receives the instruction and drives the upper door body and the lower door body to close. After closing in place, it feeds back the signal, and the solenoid valve receives the instruction to lock the upper locking component and the lower locking component.

[0049] 2) Emergency state mode

[0050] When opening the tail hatch door in the emergency state, manually operate the emergency conversion valve to switch the oil source of the tail hatch door drive system to the standby oil source. Manually operate the solenoid valve and shake the manual pump to open the upper and lower locking components. After in place, manually operate the solenoid valve to open the upper and lower door bodies.

[0051] When closing the tail hatch door in the emergency state, manually operate the emergency conversion valve to switch the oil source of the tail hatch door drive system to the original owned one. Manually operate the solenoid valve to drive the upper door body and the lower door body to close. After closing in place, the slotted hole solenoid valve makes the upper and lower locking components close.

[0052] Finally, it should be noted that the above are only preferred examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An advanced helicopter tail door system, characterized in that: it includes an upper door assembly (1) and a lower door assembly (2) respectively connected to the helicopter body. The bottom end of the upper door assembly (1) is hermetically connected to the top end of the lower door assembly (2). The upper door assembly (1) includes an upper door body (11). An upper actuator assembly (12), an upper hinge assembly (13), an upper locking assembly (14) and a jettisoning assembly (15) are provided on the upper door assembly (1). The lower door assembly (2) includes a lower door body (21). A lower actuator assembly (22), a lower hinge assembly (23), a lower locking assembly (24), a lower sealing assembly (25), a horizontal opening limit assembly (27), a spacer block assembly (28) and a gangplank assembly (29) are provided on the lower door assembly (2); The upper actuator assembly (12) includes upper actuators (121) arranged on the inner side of the upper door body (11) and on both sides of the upper door body (11). The upper actuators (121) are drivingly connected to solenoid valves. The lower actuator assembly (22) includes lower actuators (221) arranged on the inner side of the lower door body (21) and on both sides of the lower door body (21). The lower actuators (221) are also drivingly connected to solenoid valves. The upper actuators (121) are drivingly connected to the upper locking assembly (14). The lower actuators (221) are drivingly connected to the lower locking assembly (24); The jettisoning assembly (15) includes a glass (151) arranged at the bottom end of the upper door body (11). An embedded rubber strip (152) is hermetically arranged between the glass (151) and the upper door body (11). Jettisoning ribbons (153) are arranged on the inner side and the outer side of the upper door body (11) respectively. The two jettisoning ribbons (153) are respectively fixedly connected to the embedded rubber strip (152); The gangplank assembly (29) includes a gangplank mounting seat (291) installed at the top end of the lower door body (21). A second pin (292) is inserted through the gangplank mounting seat (291). A pin retaining plate (293) is arranged on the second pin (292). The second pin (292) is fixedly connected to a gangplank (294). One end of the gangplank (294) is rotatably arranged on the lower door body (21) through the second pin (292). The other end of the gangplank (294) is fixedly connected to the inner side surface of the lower door body (21) through a pull rod (295). Both ends of the pull rod (295) are movably and fixedly connected to the gangplank (294) and the lower door body (21) through a third pin (296).

2. The advanced helicopter tail door system according to claim 1, characterized in that: The upper hinge assembly (13) includes an upper tailgate side hinge (131) disposed on the inner side of the upper door body (11). One end of the upper tailgate side hinge (131) is fixedly connected to the upper door body (11), and the other end of the upper tailgate side hinge (131) is rotatably connected to a fuselage side hinge (133) through a first pin (132). The fuselage side hinge (133) is fixedly connected to the helicopter fuselage. A limiting boss (134) is further provided at the other end of the upper tailgate side hinge (131), and the limiting boss (134) is matched with the fuselage side hinge (133).

3. The advanced helicopter tail door system according to claim 1, characterized in that: The upper locking assembly (14) includes servo motors (141) disposed on both sides of the upper door body (11) and located inside the upper door body (11). Each servo motor (141) is respectively drivingly connected to a link mechanism (142), and one ends of the two link mechanisms (142) are commonly connected to a bolt lock (143).

4. The advanced helicopter tail door system according to claim 1, characterized in that: The horizontal opening limiting assembly (27) includes horizontal mooring rings (271) disposed on both sides of the lower door body (21) and located inside the lower door body (21). A horizontal mooring cable (272) is fixedly connected to the horizontal mooring ring (271). The bottom end of the horizontal mooring cable (272) is clamped inside the horizontal mooring ring (271), and the top end of the horizontal mooring cable (272) is fixedly connected to the helicopter fuselage.

5. The advanced helicopter tail door system according to claim 1, characterized in that: The cushion block assembly (28) includes two rubber blocks (281) disposed on both sides of the lower door body (21) and near the top end of the lower door body (21). The rubber blocks (281) are located on the outer side of the lower door body (21), and the rubber blocks (281) are fixedly connected to the cross beam and longitudinal beam of the lower door body (21) through bolts (282).

6. The advanced helicopter tail door system according to claim 1, characterized in that: The lower locking assembly (24) includes a lock catch seat (241) disposed on both sides of the lower door body (21) and located inside the lower door body (21). The lock catch seat (241) is matched with a lock body on the helicopter fuselage.

7. The advanced helicopter tail door system according to claim 1, characterized in that: The lower hinge assembly (23) includes a lower tailgate side hinge mounting seat (231) disposed at the bottom end of the lower door body (21). A fuselage side hinge mounting seat (232) is rotatably connected to the lower tailgate side hinge mounting seat (231) through a rotating shaft. A hinge mounting reinforcement plate (233) is further provided between the lower tailgate side hinge mounting seat (231) and the lower door body (21).

Images