Aircraft booster
By designing an aircraft booster including a transmission group, an active roller and an auxiliary roller, the existing aircraft traction device has solved the problems of large space occupied by a large turning radius and inconvenient towing at short distances, and the aircraft can effectively move within a short distance and push off the runway in an emergency situation.
Patent Information
- Application Number
- CN202422144365.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-09-02
AI Technical Summary
The existing aircraft traction devices occupy a large space, have a large turning radius, and are inconvenient towing at short distances.
An aircraft booster is designed, including a transmission set, an active roller, an auxiliary roller and a joystick assembly. The sprocket and chain are driven by the motor reducer, and the power is driven to the active roller, and the friction between the active roller and the auxiliary roller is used to push the aircraft.
The aircraft booster can efficiently move the aircraft over a short distance, with a small turning radius and reduced space occupancy, and is suitable for short distance movement and emergency situations to push the aircraft off the runway.
Smart Images
Figure CN223031270U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of boosters, in particular to an aircraft booster. Background Technique
[0002] An aircraft moves by the power of its engine, and this movement is called taxiing. If an aircraft moves without any engine assistance, it is either pushed away or pushed back. Whether an aircraft leaves the apron to the taxiway or moves between aprons, towing or boosting equipment is required. Using a tractor as a ground support equipment at the airport, its advantage is strong traction and environmental protection. Currently, the most used towing equipment at the airport is the tractor, and tractors are divided into pole tractors and towbarless tractors. The towbarless tractor has the advantage of guaranteed safety. Since the pole tractor does not directly contact the aircraft, as long as the appropriate tonnage and appropriate traction force can be selected, the function can be achieved; relatively speaking, the technology is more mature, the overall cost is lower than that of the towbarless tractor, and the later maintenance cost is lower. For small airports or airlines with low-cost operations, it is a very good choice. However, when the existing towing device is in use, there are still certain problems:
[0003] For example, an aircraft towing bar with the publication number CN201026993Y has the following technical solution: It includes a towing bar body, a tire support frame and its tires installed on the towing bar body, a towing hook installed at the front end of the towing bar body, and a towing ring installed at the rear end of the towing bar body. The towing hook is connected to the front end of the towing bar body through a slidable load-bearing shaft pin and an anti-disconnection sliding hole. An overload shear pin is fixedly connected between the towing bar body and the towing hook. However, the existing towing device needs to carry the towing bar at all times, and when the towing bar is docked with the aircraft, more patient operation is also required; some towing bars can guarantee at most two flights at the same time, while the towbarless aircraft tractor can guarantee four flights at the same time; due to the towing bar, the vehicle occupies a large space and has a relatively large turning radius, making short-distance towing inconvenient.
[0004] In view of this, in-depth research on the above problems has led to the generation of this case.
[0005] In response to the above problems, an innovative design is carried out on the basis of the original aircraft towing device. Utility Model Content
[0006] The purpose of the utility model is to provide an aircraft booster to solve the problems of large occupied space, relatively large turning radius, and inconvenient short-distance towing mentioned in the above background technique.
[0007] To achieve the above purpose, the utility model provides the following technical solutions:
[0008] An aircraft booster, comprising a transmission group, a caster assembly is installed at the rear side of the transmission group, and the transmission group is arranged on the left side of a combined frame welded part. A motor reducer is arranged on the right side of the combined frame welded part, and an output shaft of the motor reducer is connected to the transmission group. An auxiliary roller is arranged below the interior of the combined frame welded part, and both shaft ends of the auxiliary roller are inserted into holes of the combined frame welded part. A driving roller is arranged above the auxiliary roller, and both ends of the driving roller are connected to the interior of the combined frame welded part. A hand-held assembly is arranged at the rear side above the driving roller, and both left and right ends of the hand-held assembly are connected to the interior of the combined frame welded part. A battery pack is arranged at the rear side of the hand-held assembly, and a control lever assembly is arranged at the rear side of the battery pack, and the control lever assembly is welded to the upper part of the combined frame welded part.
[0009] Preferably, the transmission group includes a sprocket and a chain. An output shaft of the motor of the motor reducer is connected to the sprocket, and two sprockets are arranged at the front and rear respectively. The chain is sleeved outside the sprocket, and the front sprocket is connected and installed with the driving roller to form a rotating structure.
[0010] Adopting the above technical solution, when the motor reducer is started, it drives the rear sprocket to rotate. Through the transmission of the chain, the front sprocket is driven to rotate at the same time, thereby providing driving power for the rotation of the driving roller, so as to replace diesel engine with electric energy, which is more environmentally friendly and resource-saving.
[0011] Preferably, the driving roller includes a first rubber layer, a driving wheel main body, a first deep groove ball bearing and a bearing seat. The first rubber layer is located outside the driving wheel main body, and first deep groove ball bearings are connected and installed on both left and right sides of the driving wheel main body, and the first deep groove ball bearings form a supporting structure for the driving wheel main body.
[0012] Adopting the above technical solution, the first rubber layer outside the driving wheel main body plays a role in increasing friction and improving shock absorption performance. The driving roller is also the power output component of the whole device, with a sealed cover and filled with grease inside to ensure that it does not need to be refilled for a period of time. The first deep groove ball bearing ensures radial and axial positioning and provides low-friction rotational positioning.
[0013] Preferably, the first deep groove ball bearings are all installed and connected to the bearing seat, and the bearing seat is welded to the left and right sides inside the combined frame welded part through bolts, and the first deep groove ball bearings play a role in radial and axial positioning.
[0014] With the above technical solution, the first deep groove ball bearing is equipped with a sealed cover and filled with grease inside, ensuring that it does not need to be refilled for a period of time. The bearing ensures radial and axial positioning and provides low-friction rotational positioning. By contacting the wheel surface with the rear wheels of the aircraft, either rear wheel can be pushed according to the turning direction. If the aircraft needs to move forward, the rear wheels are pushed forward from the back of the aircraft; if the aircraft moves backward, the rear wheels are pushed backward from the front. The front wheels of the aircraft control the driving direction of the aircraft, and the synchronization of the rotation of the rear wheels of the aircraft with the wheel surface of the active rollers is ensured through friction, thereby pushing the aircraft to a fixed position.
[0015] Preferably, the auxiliary roller comprises an auxiliary wheel outer sleeve, an auxiliary wheel shaft, an auxiliary deep groove ball bearing, and an auxiliary rubber layer. Auxiliary deep groove ball bearings are connected and installed on both the left and right sides of the auxiliary wheel outer sleeve, and the auxiliary deep groove ball bearings are installed at both ends of the auxiliary wheel shaft.
[0016] With the above technical solution, the auxiliary deep groove ball bearing has dust covers at both ends and is filled with grease inside, and no additional grease needs to be added for a period of time. Moreover, the auxiliary roller shaft moves in the opposite direction to the main body of the active roller, thereby increasing the friction with the ground.
[0017] Preferably, both ends of the auxiliary wheel shaft are inserted into the holes of the combined frame welded part and form a radial fixing structure through fixing blocks. An auxiliary rubber layer is coated on the outer ring of the auxiliary wheel outer sleeve, and the auxiliary rubber layer functions to increase the friction with the active roller and the ground.
[0018] With the above technical solution, when the auxiliary roller needs to move forward, the corresponding active roller rotates backward. After the aircraft is sent to the designated position, the auxiliary roller reverses to retract the booster device. At the same time, the friction between the active roller and the ground is increased through the auxiliary rubber layer.
[0019] Preferably, the caster assembly comprises a caster body, a second deep groove ball bearing, a rear wheel shaft, and a spacer. The rear wheel shaft is connected and installed in the middle of the caster body, and the rear wheel shaft is fixedly inserted into the hole of the combined frame welded part through bolts. Second deep groove ball bearings are connected and installed at both ends of the rear wheel shaft, and a spacer is installed between the second deep groove ball bearings.
[0020] With the above technical solution, the caster assembly is installed at the tail of the booster and is not connected to the power device itself. It only plays a following role and rotates with the forward movement of the booster to provide support and stability.
[0021] Preferably, the joystick assembly comprises a push rod, a cylinder cover, an emergency stop button, an upper push hand, and a handle. The push rod is inserted into the welded pipe of the combined frame welded part. The lower part of the upper push hand is connected to the push rod through a quick-release rod, and the upper part of the upper push hand is connected to the handle through a connecting plate and bolts.
[0022] With the above technical solution, all controls are on the handle, which is simple and convenient. The speed can be adjusted - for high-speed operation and low-speed operation. The booster can be controlled to move forward, stop, and reverse. The speed control trigger at the handle can control the traveling speed.
[0023] Preferably, an emergency stop button is installed at the top of the push rod, and a cylinder cover is connected and installed at the lower end of the emergency stop button, and the cylinder cover is installed at the connection between the emergency stop button and the push rod.
[0024] With the above technical solution, there is a cable inside the emergency stop button connected to the main controller, which can make the equipment stop urgently. The cylinder cover is used to protect the connection of the emergency stop button to prevent the emergency stop button from being bumped and exposed to rain.
[0025] Compared with the prior art, the beneficial effects of the present utility model are: This aircraft booster is used for short-distance movement of aircraft, or quickly pushing the aircraft away from the runway in case of emergency during aircraft flight and adjusting the aircraft position among hangars;
[0026] 1. There are driving rollers that can replace a tractor to push the aircraft to move. The driving rollers are also the power output components of the whole device. By contacting the rear wheels of the aircraft through the wheel surface, any rear wheel can be pushed according to the turning direction. If the aircraft needs to move forward, the rear wheel is pushed forward from behind the aircraft; if the aircraft needs to move backward, the rear wheel is pushed backward from the front. The front wheels of the aircraft control the driving direction of the aircraft, and the rear wheels of the aircraft are ensured to rotate synchronously with the wheel surface of the driving rollers through friction, thereby pushing the aircraft to a fixed position;
[0027] 2. There are auxiliary rollers that increase the friction with the ground. The auxiliary rollers include an auxiliary wheel outer sleeve, an auxiliary wheel shaft, an auxiliary deep groove ball bearing, and an auxiliary rubber layer. Auxiliary deep groove ball bearings are connected and installed on both left and right sides of the auxiliary wheel outer sleeve, and the auxiliary deep groove ball bearings are installed at both left and right ends of the auxiliary wheel shaft. Both left and right ends of the auxiliary wheel shaft are inserted into the holes of the combined frame welded part and form a radial fixed structure through fixing blocks. An auxiliary rubber layer is coated on the outer ring of the auxiliary wheel outer sleeve, and the auxiliary rubber layer plays a role in increasing the friction with the driving rollers and the ground. When the auxiliary rollers need to move forward, the corresponding driving rollers rotate backward. If the aircraft has been sent to the designated position, the auxiliary rollers will reverse to withdraw the booster device, and at the same time, the friction between the driving rollers and the ground is increased through the auxiliary rubber layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 is a three-dimensional structure schematic diagram of the present utility model;
[0029] Figure 2 is a front main view structure schematic diagram of the present utility model;
[0030] Figure 3 is a front cross-sectional structure schematic diagram of the present utility model;
[0031] Figure 4 For the present utility model Figure 3 Schematic enlarged structure diagram at position A in the present utility model;
[0032] Figure 5 For the present utility model Figure 3 Schematic enlarged structure diagram at position B in the present utility model;
[0033] Figure 6 Schematic structure diagram of the caster assembly of the present utility model;
[0034] Figure 7 Schematic side structure diagram of the present utility model.
[0035] In the figure: 1. Transmission group; 101. Sprocket; 102. Chain; 2. Caster assembly; 201. Caster body; 202. Second deep groove ball bearing; 203. Rear wheel shaft; 204. Spacer assembly; 3. Auxiliary roller; 301. Auxiliary wheel outer sleeve; 302. Auxiliary wheel shaft; 303. Auxiliary deep groove ball bearing; 304. Auxiliary rubber layer; 4. Motor reducer; 5. Welded combination frame; 6. Driving roller; 601. First rubber layer; 602. Driving wheel main body; 603. First deep groove ball bearing; 604. Bearing seat; 7. Portable assembly; 8. Battery pack; 9. Joystick assembly; 901. Push rod; 902. Cylinder cover; 903. Emergency stop button; 904. Upper push handle; 905. Handle. Specific embodiments
[0036] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.
[0037] Please refer to Figure 1-7 , the present utility model provides a technical solution:
[0038] An aircraft booster, including a transmission group 1, a caster assembly 2 is installed at the rear side of the transmission group 1, and the transmission group 1 is arranged on the left side of the combined frame welded part 5. A motor reducer 4 is arranged on the right side of the combined frame welded part 5, and the output shaft of the motor reducer 4 is connected to the transmission group 1. An auxiliary roller 3 is arranged below the interior of the combined frame welded part 5, and both shaft heads at the two ends of the auxiliary roller 3 are inserted into the holes of the combined frame welded part 5. A driving roller 6 is arranged above the auxiliary roller 3, and both ends of the driving roller 6 are connected to the interior of the combined frame welded part 5. A hand-held assembly 7 is arranged at the rear side above the driving roller 6, and both the left and right ends of the hand-held assembly 7 are connected to the interior of the combined frame welded part 5. A battery pack 8 is arranged at the rear side of the hand-held assembly 7, and a joystick assembly 9 is arranged at the rear side of the battery pack 8, and the joystick assembly 9 is welded to the upper part of the combined frame welded part 5.
[0039] The transmission group 1 includes a sprocket 101 and a chain 102. The motor output shaft of the motor reducer 4 is connected to the sprocket 101, and there are two sprockets 101 arranged at the front and rear respectively. The chain 102 is sleeved and installed outside the sprocket 101, and the front sprocket 101 is connected and installed with the driving roller 6 to form a rotating structure. When the motor reducer 4 is started, it drives the rear sprocket 101 to rotate. Through the transmission of the chain 102, the front sprocket 101 is driven to rotate at the same time, thereby providing driving power for the rotation of the driving roller 6, so as to replace diesel engine with electric energy, which is more environmentally friendly and resource-saving.
[0040] The driving roller 6 includes a first rubber layer 601, a driving wheel main body 602, a first deep groove ball bearing 603 and a bearing seat 604. The first rubber layer 601 is located outside the driving wheel main body 602, and the first deep groove ball bearings 603 are connected and installed on both the left and right sides of the driving wheel main body 602, and the first deep groove ball bearings 603 form a supporting structure for the driving wheel main body 602. The first deep groove ball bearings 603 are all installed and connected to the bearing seat 604, and the bearing seat 604 is welded to the left and right sides inside the combined frame welded part 5 through bolts, and the first deep groove ball bearings 603 play a role in radial and axial positioning. The first rubber layer 601 outside the driving wheel main body 602 plays a role in increasing friction and improving shock absorption performance. The driving roller 6 is also the power output component of the whole device, with a sealing cover and filled with grease inside to ensure that it does not need to be refilled for a period of time. The first deep groove ball bearing 603 ensures radial and axial positioning and provides low-friction rotational positioning. The first deep groove ball bearing 603 has a sealing cover and is filled with grease inside to ensure that it does not need to be refilled for a period of time. The bearing ensures radial and axial positioning and provides low-friction rotational positioning. By contacting the rear wheels of the aircraft through the wheel surface, either rear wheel can be pushed according to the turning direction. If the aircraft needs to move forward, the rear wheels are pushed forward from behind the aircraft. If the aircraft moves backward, the rear wheels are pushed backward from the front. The front wheels of the aircraft control the driving direction of the aircraft, and the rear wheels of the aircraft are ensured to rotate synchronously with the wheel surface of the driving roller 6 through friction, so as to push the aircraft to a fixed position.
[0041] The auxiliary roller 3 includes an auxiliary wheel outer sleeve 301, an auxiliary wheel shaft 302, an auxiliary deep groove ball bearing 303 and an auxiliary rubber layer 304. Auxiliary deep groove ball bearings 303 are connected and installed on both the left and right sides of the auxiliary wheel outer sleeve 301, and the auxiliary deep groove ball bearings 303 are installed at both the left and right ends of the auxiliary wheel shaft 302. Both the left and right ends of the auxiliary wheel shaft 302 are inserted into the holes of the combined frame welded part 5 and form a radial fixing structure through fixing blocks. A layer of auxiliary rubber layer 304 is coated on the outer ring of the auxiliary wheel outer sleeve 301, and the auxiliary rubber layer 304 functions to increase the friction with the driving roller 6 and the ground. The auxiliary deep groove ball bearing 303 has dust covers at both ends and is filled with grease, so that grease does not need to be added for a period of time. Moreover, the auxiliary wheel shaft 302 moves in the opposite direction to the driving wheel main body 602, thereby increasing the friction with the ground. When the auxiliary roller 3 needs to move forward, the corresponding driving roller 6 rotates backward. If the aircraft is sent to the designated position, the auxiliary roller 3 will reverse to retract the booster device. At the same time, the friction between the driving roller 6 and the ground is increased through the auxiliary rubber layer 304.
[0042] The caster assembly 2 includes a caster body 201, a second deep groove ball bearing 202, a rear wheel shaft 203 and a spacer assembly 204. The rear wheel shaft 203 is connected and installed in the middle of the caster body 201, and the rear wheel shaft 203 is fixedly inserted into the hole of the combined frame welded part 5 through bolts. Second deep groove ball bearings 202 are connected and installed at both ends of the rear wheel shaft 203, and a spacer assembly 204 is installed between the second deep groove ball bearings 202. The caster assembly 2 is installed at the tail of the booster and is not connected to the power device itself. It only plays a following role and rotates with the forward movement of the booster to play a role in supporting and stabilizing.
[0043] The joystick assembly 9 includes a push rod 901, a cylinder cover 902, an emergency stop button 903, an upper push handle 904 and a handle 905. The push rod 901 is inserted into the welded pipe of the combined frame welded part 5, and the lower part of the upper push handle 904 is connected to the push rod 901 through a quick-release rod, and the upper part of the upper push handle 904 is connected to the handle 905 through a connecting disc and bolts. An emergency stop button 903 is installed at the top of the push rod 901, and a cylinder cover 902 is connected and installed at the lower end of the emergency stop button 903, and the cylinder cover 902 is installed at the connection between the emergency stop button 903 and the push rod 901. All controls are on the handle 905, which is simple and convenient. The speed can be adjusted - high-speed operation and low-speed operation. The booster can be controlled to move forward, stop and reverse. The speed control trigger at the handle 905 can control the traveling speed. There is a cable in the emergency stop button 903 connected to the main controller, which can make the equipment stop urgently. The cylinder cover 902 is used to protect the connection of the emergency stop button 903 to prevent the emergency stop button 903 from being bumped and getting wet.
[0044] Working principle:
[0045] When the utility model is in use, the wheel surface of the driving wheel main body 602 contacts with the rear wheel of the aircraft, the motor reducer 4 is started to drive the rear sprocket 101 to rotate, and the front sprocket 101 is driven to rotate simultaneously through the transmission of the chain 102, so as to provide driving power for the rotation of the driving roller 6. Any rear wheel can be pushed according to the turning direction. If the aircraft needs to move forward, the rear wheel is pushed forward from the back of the aircraft; if the aircraft moves backward, the rear wheel is pushed backward from the front. The front wheel of the aircraft controls the driving direction of the aircraft, and the friction force ensures that the rear wheel of the aircraft rotates synchronously with the wheel surface of the driving roller 6, so as to push the aircraft to a fixed position. The auxiliary roller 3 needs to move forward, and the corresponding driving roller 6 rotates backward. If the aircraft is sent to the designated position, the auxiliary roller 3 rotates reversely to withdraw the booster device. There is a cable in the emergency stop button 903 connected to the main controller, which can stop the equipment emergently.
[0046] The content not detailed in this specification belongs to the prior art well known to those skilled in the art.
[0047] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.
Claims
1. An aircraft booster, comprising a transmission group (1), characterized in that: A caster assembly (2) is installed at the rear side of the transmission group (1), and the transmission group (1) is arranged on the left side of the combination frame welding part (5). A motor reducer (4) is arranged on the right side of the combination frame welding part (5), and the output shaft of the motor reducer (4) is connected to the transmission group (1). An auxiliary roller (3) is arranged at the lower part of the combination frame welding part (5), and the shaft heads at both ends of the auxiliary roller (3) are inserted into the holes of the combination frame welding part (5). An active roller (6) is arranged above the auxiliary roller (3), and both ends of the active roller (6) are connected to the inside of the combination frame welding part (5). A handheld component (7) is arranged at the rear side above the active roller (6), and the left and right ends of the handheld component (7) are connected to the inside of the combination frame welding part (5). A battery pack (8) is arranged at the rear side of the handheld component (7), and a joystick component (9) is arranged at the rear side of the battery pack (8), and the joystick component (9) is welded to the top of the combination frame welding part (5).
2. An aircraft booster according to claim 1, characterized in that: The transmission group (1) comprises a sprocket (101) and a chain (102); the motor output shaft of the motor reducer (4) is connected to the sprocket (101), and two sprockets (101) are arranged at the front and rear; the chain (102) is sleeved and installed on the outside of the sprocket (101), and the front sprocket (101) is connected and installed with a driving roller (6) to form a rotating structure.
3. An aircraft booster according to claim 2, characterized in that: The active roller (6) comprises a first rubber layer (601), an active wheel body (602), a first deep groove ball bearing (603) and a bearing seat (604); the first rubber layer (601) is located outside the active wheel body (602); the first deep groove ball bearing (603) is connected and installed on both sides of the active wheel body (602); and the first deep groove ball bearing (603) forms a supporting structure for the active wheel body (602).
4. An aircraft booster according to claim 3, characterized in that: The first deep groove ball bearings (603) are all installed and connected to the bearing seats (604), and the bearing seats (604) are welded to the left and right sides of the combined frame welding part (5) by bolts, and the first deep groove ball bearings (603) have radial and axial positioning functions.
5. The aircraft booster according to claim 1, characterized in that: The auxiliary roller (3) comprises an auxiliary wheel outer shell (301), an auxiliary wheel shaft (302), an auxiliary deep groove ball bearing (303) and an auxiliary rubber layer (304); the auxiliary deep groove ball bearings (303) are connected and installed on both left and right sides of the auxiliary wheel outer shell (301), and the auxiliary deep groove ball bearings (303) are installed on both left and right ends of the auxiliary wheel shaft (302).
6. An aircraft booster according to claim 5, characterized in that: The left and right ends of the auxiliary wheel shaft (302) are inserted into the holes of the combined frame welding piece (5) through the fixing blocks to form a radial fixing structure. The outer ring of the auxiliary wheel jacket (301) is coated with an auxiliary rubber layer (304), and the auxiliary rubber layer (304) is configured to increase the friction between the active roller (6) and the ground.
7. An aircraft booster according to claim 1, characterized in that: The caster assembly (2) comprises a caster body (201), a second deep groove ball bearing (202), a rear wheel axle (203) and a spacer component (204); the rear wheel axle (203) is connected and installed in the middle of the caster body (201), and the rear wheel axle (203) is fixed by bolts and inserted into the hole of the combined frame welding part (5); the second deep groove ball bearings (202) are connected and installed at both ends of the rear wheel axle (203), and the spacer component (204) is installed between the second deep groove ball bearings (202).
8. An aircraft booster according to claim 1, characterized in that: The joystick assembly (9) comprises a push rod (901), a cylinder cover (902), an emergency stop button (903), an upper push handle (904) and a handle (905); the push rod (901) is inserted into the welding pipe of the combination frame welding part (5); the lower part of the upper push handle (904) is connected to the push rod (901) through a quick release rod, and the upper part of the upper push handle (904) is connected to the handle (905) through a connecting plate and bolts.
9. An aircraft booster according to claim 8, characterized in that: The top end of the push rod (901) is equipped with an emergency stop button (903), and the lower end of the emergency stop button (903) is connected and equipped with a cylinder cover (902), and the cylinder cover (902) is installed at the connection between the emergency stop button (903) and the push rod (901).
Citation Information
Patent Citations
Drawbar of airplane
CN201026993Y
Cited By
Railway freight carriage propelling device
CN121799463A