Aircraft tractor

Abstract

The invention relates to an aircraft tractor. The aircraft tractor comprises a frame, wheels, and a bracket, wherein the front part of the bracket is movably arranged on the frame; the front part of the bracket is matched with the frame in a horizontal direction to prevent the bracket from swinging relative to the frame in a horizontal plane; a torque sensor is provided on the bracket to measure the steering torque between the bracket and the frame; a controller is connected to the torque sensor to control the steering of the wheel according to the measured value of the torque sensor, and the torque between the frame and the bracket in the horizontal plane can be measured by the torque sensor. During the steering process of the aircraft tractor of the invention, the controller can control the steering of the wheel according to the value measured by the torque sensor, and when the value measured by the torque sensor is too large, the wheel can be controlled to rotate in the opposite direction or stop increasing the turning angle further, so as to avoid damage to the front landing gear, thereby solving the problem that the current aircraft tractor is easy to cause damage to the aircraft landing gear during the steering process.

Description

Technical Field

[0001] The present invention relates to an aircraft tug. Background Art

[0002] Aircraft tractors are important equipment to ensure the ground mobility of aircraft. According to different traction methods, aircraft tractors are divided into towing with a rod and towing without a rod. Towing with a rod means that the aircraft tractor is connected to the front landing gear of the aircraft through a towing rod to achieve towing or pushing the aircraft. Towing without a rod means that the aircraft tractor carries the front landing gear of the aircraft, and the tractor and the aircraft form a whole to achieve towing or pushing the aircraft. Towing without a rod is simple to operate, has a small turning radius, requires fewer support personnel, and has good versatility.

[0003] The rodless aircraft tractor is provided with a wheel clamping mechanism for clamping the front landing gear of the aircraft. A Chinese patent with the authorization announcement number CN206750172U and the authorization announcement date 2017.12.15 discloses a rodless aircraft tractor, the tractor includes a main frame under the vehicle, the main frame under the vehicle includes a driving wheel assembly, a steering wheel assembly, and a U-shaped frame, and an interface for connecting the wheel lifting mechanism is provided in the main frame under the vehicle, which can fix the wheel lifting mechanism inside the main frame under the vehicle, providing a support carrier for the action of the wheel lifting mechanism.

[0004] The wheel-holding lifting mechanism includes a main frame assembly, a sliding beam assembly and a main crossbeam assembly. The main crossbeam assembly is hinged to the front support plate and the rear support plate. The two ends of the main crossbeam assembly are supported by two hydraulic cylinders. The mounting seat of the hydraulic cylinder has three degrees of freedom of rotation, so that the main crossbeam assembly can rotate relative to the main frame assembly. The main frame assembly is connected to the rear connecting seat of the main frame through a pin shaft. The rear connecting seat of the main frame is connected to the piston rod of the hydraulic cylinder through a hinge with three degrees of freedom. The rear connecting seat of the main frame is driven up and down by the hydraulic cylinder, and can move relative to the main frame under the vehicle. The main crossbeam assembly rises and falls under the action of the hydraulic cylinders at both ends, which can drive the main frame assembly to rise and fall synchronously. The rear end of the main frame assembly rises and falls under the action of another hydraulic cylinder. The main frame assembly is used to support the bracket of the aircraft landing gear. The main crossbeam assembly and the hydraulic cylinders at both ends form a bracket suspension mechanism for lifting the bracket.

[0005] When the aircraft tractor rotates along the vertical axis, the main frame assembly rotates with the tractor and can adaptively rotate around the hinge shaft of the supporting vertical plate on the tractor to avoid generating additional torque on the aircraft landing gear.

[0006] During the turning process of the tractor, two steering wheel assemblies are used to provide a steering angle for the vehicle body to turn. The control circuit of the controller controls the steering and speed of the drive motors of the two drive wheel assemblies according to the Ackerman algorithm, so that the tractor can turn smoothly. This aircraft tractor will generate a steering torque on the aircraft landing gear during the turning process. When the steering torque exceeds the set value, it is easy to cause damage to the aircraft landing gear. Therefore, different turning angles need to be set for different aircraft landing gears in actual use. However, even so, due to the influence of factors such as ground friction and the shape of the aircraft landing gear, the steering torque will still change when turning at the set turning angle, and it is still easy to cause damage to the aircraft landing gear. Summary of the invention

[0007] The object of the present invention is to provide an aircraft tractor, which is used to solve the problem that the current aircraft tractor is prone to damage the aircraft landing gear during the turning process.

[0008] The aircraft tractor of the present invention adopts the following technical solutions:

[0009] Aircraft tractor includes:

[0010] A frame, the rear end of which has an opening for the nose landing gear of the aircraft to enter;

[0011] wheel;

[0012] A bracket used to hold up the front landing gear of the aircraft;

[0013] The bracket suspension mechanism includes a crossbeam and suspension mechanism oil cylinders at both ends of the crossbeam, the two ends of the crossbeam are supported on the frame through the suspension mechanism oil cylinders, the middle of the crossbeam suspends the rear part of the bracket, the crossbeam and the rear part of the bracket are hinged through the crossbeam hinge shaft, and the two ends of the crossbeam can swing forward and backward relative to the frame and can swing left and right relative to the frame;

[0014] The front part of the bracket is movably arranged on the frame;

[0015] The front part of the bracket is matched with the frame in the horizontal direction to prevent the bracket from swinging relative to the frame in the horizontal plane;

[0016] A torque sensor is provided on the bracket to measure the steering torque between the bracket and the frame;

[0017] The controller is connected to the torque sensor and controls the steering of the wheel according to the measurement value of the torque sensor.

[0018] Beneficial effects: Since the two ends of the crossbeam suspending the bracket at the rear of the bracket can move forward, backward, left and right, the front of the bracket and the frame are stopped from rotating, and the torque between the frame and the bracket in the horizontal plane can be measured by the torque sensor, during the steering process of the aircraft tractor of the present invention, the controller can control the steering of the wheels according to the value measured by the torque sensor. When the value measured by the torque sensor is too large, the wheels can be controlled to rotate in the opposite direction or stop increasing the turning angle. The front landing gear is not easily damaged, which solves the problem that the current aircraft tractor is easy to cause damage to the aircraft landing gear during the steering process.

[0019] Furthermore, the torque sensor is arranged at the front end of the bracket, which is convenient for the installation of the torque sensor, and the deformation of the front end of the bracket is small during measurement, and the structure is relatively stable.

[0020] Furthermore, the bracket includes a frame body and a connecting structure arranged at the front end of the frame body, the bracket is connected to the frame via the connecting structure, and the frame body is connected to the connecting structure via the torque sensor, so as to facilitate the installation of the torque sensor.

[0021] Furthermore, the torque sensor is provided with connecting flanges at both ends, and the torque sensor is fixedly connected to the frame and the connecting structure through the connecting flanges at both ends, so as to facilitate the installation of the sensor and ensure the fixing effect.

[0022] Furthermore, the controller controls the wheel to rotate in the opposite direction after the measured value of the torque sensor reaches a set value, thereby further preventing the front landing gear of the aircraft from being easily damaged.

[0023] Furthermore, a cylinder seat is provided on the periphery of the suspension mechanism oil cylinder, two cylinder articulation shafts extending forward and backward and coaxial are fixed on the cylinder body of the suspension mechanism oil cylinder, a cylinder seat articulation shaft extending left and right is provided on the cylinder seat, and the cylinder seat articulation shaft is articulated on the vehicle frame, and the two ends of the crossbeam swing forward and backward relative to the vehicle frame through the cylinder seat articulation shaft, and swing left and right relative to the vehicle frame through the cylinder articulation shaft. The cylinder seat is sleeved on the periphery of the suspension mechanism oil cylinder, so that the suspension mechanism oil cylinder is more evenly stressed and has better stability.

[0024] Furthermore, the bracket includes a frame body and a ball joint structure arranged at the front end of the frame body, the ball joint structure includes a frame body connection seat connected to the frame body and a spherical fitting part, the spherical fitting part is installed on the frame, and the spherical fitting part and the frame body connection seat cooperate with each other through spherical movement, so that the bracket can swing up and down, and can swing around the central axis of the crossbeam hinge axis; a rotation-stopping cylindrical surface is arranged on the front side of the frame body connection seat, and the rotation-stopping cylindrical surface extends forward and backward and is coaxial with the crossbeam hinge axis; the frame is provided with rotation-stopping surfaces on the left and right sides of the rotation-stopping cylindrical surface, and the rotation-stopping cylindrical surface is tangent to the rotation-stopping surfaces on the left and right sides to achieve the rotation-stopping cooperation between the bracket and the frame in the horizontal direction. The ball joint structure and the rotation-stopping cylindrical surface can realize the up and down swinging of the bracket relative to the frame and the swinging around the crossbeam hinge axis, and the rear end of the bracket is only supported by the ball joint structure, so the structure is simpler and easy to install.

[0025] Furthermore, the ball joint structure includes a joint bearing, the inner ring of the joint bearing constitutes the spherical matching part, and the outer ring of the joint bearing is installed on the frame connecting seat. As a standard part, the joint bearing has good stability and low cost.

[0026] Furthermore, a rotation-stopping cylinder is fixed to the front side of the frame connecting seat, and the outer peripheral surface of the rotation-stopping cylinder constitutes the rotation-stopping cylindrical surface. The cylinder has high strength and can withstand a large torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural schematic diagram of a specific embodiment 1 of the aircraft tractor of the present invention;

[0028] Figure 2 It is a structural schematic diagram of a bracket in a specific embodiment 1 of an aircraft tractor of the present invention;

[0029] Figure 3 It is a schematic diagram of force analysis of a vertical surface in a specific embodiment 1 of the aircraft tractor of the present invention;

[0030] Figure 4 It is a schematic diagram of force analysis on the horizontal plane in the specific embodiment 1 of the aircraft tractor of the present invention;

[0031] Figure 5 Schematic diagram of the installation structure of the torque sensor in the specific embodiment 1 of the aircraft tractor of the present invention;

[0032] Figure 6 is another schematic diagram of the installation structure of the torque sensor in the specific embodiment 1 of the aircraft tractor of the present invention;

[0033] Figure 7 It is a structural schematic diagram of the ball joint structure in the specific embodiment 1 of the aircraft tractor of the present invention;

[0034] Figure 8It is a structural schematic diagram of the connection between the bracket and the frame in the specific embodiment 1 of the aircraft tractor of the present invention;

[0035] In the figure: 1. frame; 11. mounting plate; 111. anti-rotation surface; 2. bracket; 21. rear door stop; 22. front clamp; 23. frame; 24. frame connecting seat; 241. connecting ear; 242. fixing step; 25. spherical bearing; 251. bearing inner ring; 26. mounting shaft; 27. anti-rotation cylinder; 271. anti-rotation cylindrical surface; 3. wheel; 4. front landing gear; 5. bracket suspension mechanism; 51. crossbeam; 52. suspension mechanism cylinder; 521. piston rod; 522. suspension mechanism cylinder; 523. cylinder articulation shaft; 53. crossbeam articulation shaft; 54. cylinder seat; 541. cylinder seat articulation shaft; 6. torque sensor; 61. upper connecting flange; 62. lower connecting flange. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0038] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0039] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0040] Specific embodiment 1 of the aircraft tractor of the present invention:

[0041] like Figures 1 to 6 As shown, the aircraft tractor includes a frame 1 and a bracket 2, and the frame 1 is equipped with wheels 3, a drive system and a steering system, wherein the drive system and the steering system are both existing technologies and will not be described in detail in this embodiment.

[0042] The bracket 2 is used to hold up the front landing gear 4 of the aircraft so that the aircraft tractor can tow the aircraft. In this embodiment, the frame 1 is a U-shaped frame, and the rear end of the frame 1 has an opening for the front landing gear 4 of the aircraft to enter. The bracket 2 is provided with a rear door stopper 21 and a front clamp 22, wherein the structure of the bracket 2 clamping the front landing gear 4 of the aircraft is the prior art, and is the same as the structure of the wheel-holding lifting mechanism disclosed in the Chinese patent document with the authorization announcement number CN206750172U, which will not be described in detail here, and this embodiment mainly focuses on the improvement of the prior art.

[0043] The rear end of the bracket 2 is suspended on the frame 1 through the bracket suspension mechanism 5. Figure 2 As shown, the bracket suspension mechanism 5 includes a crossbeam 51 and a suspension mechanism oil cylinder 52 at both ends of the crossbeam 51. The two ends of the crossbeam 51 are supported on the frame 1 through the suspension mechanism oil cylinder 52. The middle of the crossbeam 51 suspends the rear part of the bracket 2. The crossbeam 51 and the rear part of the bracket 2 are hinged through the crossbeam hinge shaft 53. There are two degrees of freedom between the cylinder seat 54 of the suspension mechanism oil cylinder 52 and the frame 1. At the same time, the crossbeam 51 is hinged at the top of the piston rod 521 of the suspension mechanism oil cylinder 52, so that the two ends of the crossbeam 51 can swing forward and backward relative to the frame 1, and can swing left and right relative to the frame 1. The oil cylinder seat 54 in this embodiment is sleeved on the suspension mechanism oil cylinder 52. Of course, in other embodiments, the connection form of the suspension mechanism oil cylinder and the frame can also adopt the method in the authorization announcement number CN206750172U.

[0044] like Figure 2 As shown, two cylinder articulated shafts 523 extending forward and backward are fixed on the suspension mechanism cylinder body 522 of the suspension mechanism cylinder 52, and the cylinder seat 54 is sleeved on the outside of the suspension mechanism cylinder 52. The cylinder seat 54 is provided with a cylinder seat groove for the cylinder articulated shaft 523 to cooperate with, and the outer side of the cylinder seat 54 is also provided with two left and right coaxial cylinder seat articulated shafts 541, and the cylinder seat articulated shaft 541 is hinged to the frame 1.

[0045] In this embodiment, the bracket 2 includes a frame body 23 and a ball joint structure arranged at the front end of the frame body 23, the ball joint structure includes a frame body connection seat 24 connected to the frame body 23 and a spherical matching piece that is spherically matched with the frame body connection seat 24, in this embodiment, the ball joint structure includes a joint bearing 25, the bearing inner ring 251 of the joint bearing 25 constitutes a spherical matching piece, and the outer ring of the joint bearing 25 is fixed on the frame body connection seat 24. The bearing inner ring 251 is fixed on the mounting shaft 26, and the mounting shaft 26 extends left and right and is installed on the vehicle frame 1.

[0046] A stop cylinder 27 is fixed to the front side of the frame connecting seat 24, and the outer circumferential surface of the stop cylinder 27 constitutes the stop cylindrical surface 271. The stop cylindrical surface 271 is coaxially arranged with the cross beam hinge axis 53. The frame 1 includes two left and right opposite mounting plates 11, and the two ends of the mounting axis 26 are respectively assembled on the mounting plates 11. The opposite side surfaces of the two mounting plates 11 form a stop surface 111 tangent to the stop cylindrical surface 271. The stop surface 111 is a plane extending forward and backward and arranged vertically. The stop surface 111 is tangent to the stop cylindrical surface 271 so that the bracket 2 can cooperate with the frame 1 in the horizontal direction and the bracket 2 can swing up and down to adapt to the up and down movement of the landing gear relative to the frame 1. In addition, the frame 1 can swing around the central axis of the stop cylindrical surface 271, so that the bracket 2 can swing around the axis of the cross beam hinge axis 53 relative to the frame 1 to adapt to the inclination of the landing gear during turning. In order to prevent the frame 1 from affecting the anti-rotation cylinder 27 , the movable space between the two mounting plates 11 is provided for the anti-rotation cylinder 27 to move, and there is a gap between the front side of the anti-rotation cylinder 27 and the frame 1 .

[0047] The joint bearing 25 and the anti-rotation cylinder 27 can simplify the connection structure between the frame 1 and the front end of the bracket, making installation and maintenance easier.

[0048] The bracket 2 is connected to the vehicle frame 1 by means of a bracket suspension mechanism 5 at the rear and a ball joint structure at the front, and the bracket 2 is lifted and lowered by a suspension mechanism oil cylinder 52 of the bracket suspension mechanism 5, thereby controlling the lifting and lowering of the front landing gear 4. In this embodiment, the rear portion of the bracket 2 swings up and down to lift and lower the front landing gear 4.

[0049] When the aircraft tractor turns, there is a steering torque between the aircraft tractor and the front landing gear 4. In order to prevent the front landing gear 4 from being damaged by excessive steering torque, a torque sensor 6 is provided at the front of the bracket 2 of the present invention. The torque sensor 6 is arranged between the bracket 2 and the frame connecting seat 24 of the ball joint structure. The torque sensor 6 includes an upper connecting flange 61 and a lower connecting flange 62. The upper connecting flange 61 is fixed to the bracket 2, and the lower connecting flange 62 is fixed to the frame connecting seat 24.

[0050] like Figure 7 and Figure 8As shown, the frame connecting seat 24 includes a connecting ear 241 at the front end, and the connecting ear 241 is used to install the outer ring of the spherical bearing 25 and the anti-rotation cylinder 27, and the anti-rotation cylinder 27 is fixed to the connecting ear 241. A fixing step 242 is provided at the rear side of the frame connecting seat 24, and the lower connecting flange 62 is fixed to the fixing step 242 by bolts. The upper connecting flange 61 is fixed to the frame 23 by bolts.

[0051] As shown in the figure, since the crossbeam 51 can move forward, backward, left and right, it only provides a vertical upward force for the bracket 2. The force on the tractor is balanced in the vertical plane, and the tractor is subjected to the steering force of the front wheels of the tractor in the horizontal plane. The torque generated by the torque sensor 6 is the product of the steering force provided by the front wheels of the aircraft tractor and the lever arm.

[0052] The controller of the aircraft tractor is connected to the torque sensor 6. The controller controls the steering of the wheel 3 according to the value measured by the torque sensor 6. When the value of the torque sensor 6 exceeds the set value, the wheel 3 is controlled to rotate in the opposite direction to avoid damage to the front landing gear 4.

[0053] When the aircraft tractor of the present invention is working, the piston rod 521 of the suspension mechanism oil cylinder 52 is retracted, the crossbeam 51 is lowered, the rear part of the bracket 2 is lowered, the rear door stop 21 at the rear end of the bracket 2 is opened, and after the front landing gear 4 moves onto the bracket 2, the rear door stop 21 is closed, and the front clamp 22 on the bracket 2 holds the wheel of the front landing gear 4 tightly, and then the suspension mechanism oil cylinder 52 is raised, and the aircraft tractor can tow the aircraft to move and turn. During the moving and turning process, the bracket 2 can swing around the crossbeam hinge shaft 53, and can swing up and down to reduce the additional torque of the aircraft landing gear. For the steering torque received by the aircraft landing gear during the turning process, the controller can control the steering of the aircraft tractor according to the steering torque. When the torque received by the front landing gear 4 exceeds the set value, the controller controls the aircraft tractor to reverse the steering. For different types of front landing gears 4 and different road conditions, the aircraft tractor of the present invention can monitor the steering torque received by the front landing gear 4 in real time to avoid damage to the front landing gear 4.

[0054] The specific embodiment 2 of the aircraft tug of the present invention has a structure that is different from that of the specific embodiment 1 of the aircraft tug mentioned above only in that: in this embodiment, the torque sensor is arranged in the middle of the bracket, and the steering torque of the front landing gear is obtained through conversion.

[0055] The specific embodiment 3 of the aircraft tractor of the present invention has a structure that is different from that of the specific embodiment 1 of the aircraft tractor described above only in that the torque sensor is disposed between the hinge structure and the vehicle frame.

[0056] The specific embodiment 4 of the aircraft tractor of the present invention has a structure that is different from that of the specific embodiment 1 of the aircraft tractor described above only in that a front end supporting cylinder is provided at the front end of the bracket, the front end of the bracket is supported by the front end supporting cylinder, and the hinged structure of the bracket is hinged on the piston rod of the front end supporting cylinder.

[0057] The specific embodiment 5 of the aircraft tractor of the present invention has a structure that is different from that of the specific embodiment 1 of the aircraft tractor described above only in that the cylinder seat of the suspension mechanism cylinder can be set at the bottom of the cylinder.

[0058] In the specific embodiment 6 of the aircraft tractor of the present invention, the structure of the aircraft tractor in this embodiment is different from that in the specific embodiment 1 of the aircraft tractor described above only in that: in this embodiment, a round tube is used instead of a rotation-stopping cylinder, and the outer peripheral surface of the round tube forms a rotation-stopping cylindrical surface. In other embodiments, in order to reduce friction, the rotation-stopping cylinder or the round tube can be rotatably assembled on the vehicle frame.

[0059] The specific embodiment 7 of the aircraft tractor of the present invention, the structure of the aircraft tractor in this embodiment is different from that in the specific embodiment 1 of the above-mentioned aircraft tractor only in that a ball head is provided on the frame connecting seat, a spherical mating part mating with the ball head is fixed on the frame, and a stop cylinder is fixed on the ball head.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. Aircraft tractor, including: A frame, the rear end of which has an opening for the nose landing gear of the aircraft to enter; wheel; A bracket used to hold up the front landing gear of the aircraft; The bracket suspension mechanism includes a crossbeam and suspension mechanism oil cylinders at both ends of the crossbeam, the two ends of the crossbeam are supported on the frame through the suspension mechanism oil cylinders, the middle of the crossbeam suspends the rear part of the bracket, the crossbeam and the rear part of the bracket are hinged through the crossbeam hinge shaft, and the two ends of the crossbeam can swing forward and backward relative to the frame and can swing left and right relative to the frame; The front part of the bracket is movably arranged on the frame; The invention is characterized in that the front part of the bracket is anti-rotatably matched with the frame in the horizontal direction to limit the swing of the bracket relative to the frame in the horizontal plane; A torque sensor is provided on the bracket to measure the steering torque between the bracket and the frame in the horizontal plane; The controller is connected to the torque sensor and controls the steering of the wheel according to the measurement value of the torque sensor.

2. The aircraft tractor according to claim 1, characterized in that: The torque sensor is arranged at the front end of the bracket.

3. The aircraft tractor according to claim 2, characterized in that: The bracket comprises a frame body and a connecting structure arranged at the front end of the frame body, the bracket is connected to the vehicle frame via the connecting structure, and the frame body is connected to the connecting structure via a torque sensor.

4. The aircraft tug according to claim 3, characterized in that: The torque sensor is provided with connecting flanges at both ends, and the torque sensor is fixedly connected to the frame and the connecting structure through the connecting flanges at both ends.

5. The aircraft tractor according to any one of claims 1 to 4, characterized in that: The controller controls the wheel to rotate in the opposite direction after the measured value of the torque sensor reaches a set value.

6. The aircraft tractor according to any one of claims 1 to 4, characterized in that: The outer sleeve of the suspension mechanism cylinder is provided with a cylinder seat, and two coaxial cylinder articulated shafts extending forward and backward are fixed on the cylinder body of the suspension mechanism cylinder. The cylinder seat is provided with a cylinder seat articulated shaft extending left and right, and the cylinder seat articulated shaft is hinged to the frame. The two ends of the crossbeam swing forward and backward relative to the frame through the cylinder seat articulated shaft, and swing left and right relative to the frame through the cylinder articulated shaft.

7. The aircraft tug according to claim 1, characterized in that: The bracket includes a frame body and a ball-joint structure arranged at the front end of the frame body, the ball-joint structure includes a frame connecting seat connected to the frame body and a spherical fitting part, the spherical fitting part is installed on the frame, and the spherical fitting part and the frame connecting seat are spherically matched to enable the bracket to swing up and down and around the central axis of the crossbeam hinge shaft; a stop cylindrical surface is arranged on the front side of the frame connecting seat, the stop cylindrical surface extends forward and backward and is coaxial with the crossbeam hinge shaft; the frame is provided with stop surfaces on the left and right sides of the stop cylindrical surface, the stop cylindrical surface is tangent to the stop surfaces on the left and right sides, so as to realize the stop cooperation between the bracket and the frame in the horizontal direction.

8. The aircraft tug according to claim 7, characterized in that: The ball joint structure comprises a spherical bearing, the inner ring of which constitutes the spherical fitting, and the outer ring of which is mounted on the frame connecting seat.

9. The aircraft tug according to claim 7, characterized in that: A rotation-stopping cylinder is fixed on the front side of the frame connecting seat, and the outer peripheral surface of the rotation-stopping cylinder constitutes the rotation-stopping cylindrical surface.

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