Safety locking structure for preventing overspeed of jib of aerial platform
By employing a dual-safety-locking structure on the aerial work platform, and utilizing sensors to detect abnormal speeds and trigger locking actions, the stalling problem caused by hydraulic leakage or seal failure in existing devices has been solved. This achieves efficient safety locking and convenient operation, while reducing maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XUZHOU ANRUOTAI HEAVY IND MACHINERY CO LTD
- Filing Date
- 2026-04-03
- Publication Date
- 2026-05-29
AI Technical Summary
Existing anti-stall devices for aerial work platforms are prone to failure due to hydraulic leakage, valve core jamming, or seal failure, making it impossible to lock the telescopic boom. Furthermore, they are complex in structure, inconvenient to operate and maintain, increasing equipment costs and maintenance difficulty.
The device employs a safety locking structure that includes components such as a telescopic boom, bracket, suction switch, limit block, ratchet rack and pinion, and controller. It achieves timely locking of the telescopic boom through a double safety mechanism and uses sensors to detect abnormal speed and trigger the locking action, ensuring that the device can still work effectively in the event of a hydraulic system failure.
It effectively prevents the telescopic boom from descending rapidly due to hydraulic leakage or seal failure, improving safety and ease of operation, reducing maintenance costs, and extending the service life of the equipment.
Smart Images
Figure CN122102011A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of safety protection technology for aerial work platforms, and more specifically, it relates to a safety locking structure for preventing the boom of an aerial work platform from stalling. Background Technology
[0002] As core operational equipment in fields such as power maintenance, municipal maintenance, engineering construction, and stadium maintenance, aerial work platforms face complex and variable operating environments during actual operation. They also need to withstand long-term loads and are affected by various factors such as hydraulic system wear, mechanical component aging, and electrical control failures, inevitably leading to various mechanical failures. Among these, the loss of braking function and rapid descent of the telescopic boom is one of the most dangerous failures. This failure not only directly threatens the lives of aerial workers but also causes the telescopic boom to collide violently with ground objects, severely damaging the boom structure, hydraulic system, and other core components of the aerial work platform. This significantly shortens the equipment's service life and increases maintenance costs and downtime losses. Currently, while some existing aerial work platforms are equipped with certain anti-stall devices, such as balance valves in the hydraulic system, which can theoretically prevent the boom from stalling and falling, some of these devices are linked to the main hydraulic system of the aerial work platform. When the main hydraulic system experiences problems such as hydraulic oil leakage, valve core jamming, or poor sealing, the anti-stall device will fail simultaneously and will not be able to play a braking and locking role. This will lead to the boom descending rapidly, causing safety accidents and equipment damage. For example, when the seals of the telescopic cylinder are aged and damaged, causing internal leakage of hydraulic oil, or when there is internal leakage in the proportional directional valve, the existing anti-stall device cannot lock the telescopic boom in time, which can easily lead to the boom sinking automatically or falling rapidly. Furthermore, existing anti-stall devices have complex structural designs, poor operational convenience, and high maintenance costs. Some devices rely on precision hydraulic components, which not only increases the manufacturing cost of the equipment but also makes subsequent maintenance more difficult. Summary of the Invention
[0003] To address the technical issues that existing anti-stall devices often rely on hydraulic balance valves and are linked to the main hydraulic system, the anti-stall function will fail simultaneously in the event of hydraulic leakage, valve core jamming, or seal failure, making it impossible to lock the boom. In addition, these devices are complex in structure, inconvenient to operate and maintain, and have high costs, this paper proposes a safe locking structure to prevent the boom of an aerial work platform from stalling.
[0004] To achieve the above objectives, the technical solution adopted in this application is: a safety locking structure for preventing the boom of an aerial work platform from stalling, comprising a telescopic boom, wherein a plurality of telescopic booms are provided, the size of the plurality of telescopic booms decreasing sequentially and being connected to each other, and a bracket is fixedly connected to the end face of the plurality of telescopic booms near the top. The locking assembly is located at the top of the telescopic boom and is capable of locking the telescopic boom in the event of stall. The locking assembly also includes a double safety mechanism that works in conjunction with the locking assembly.
[0005] Preferably, the locking assembly includes a U-shaped plate, a pull switch, and a connecting groove. The U-shaped plate is fixedly connected to the end face of the bracket away from the telescopic arm. The bottom of the U-shaped plate is closed. A pull switch is installed at the bottom of the inner cavity of the U-shaped plate. The telescopic end of the pull switch passes through the U-shaped plate and is slidably connected to the U-shaped plate. The telescopic end of the pull switch has a connecting groove.
[0006] Preferably, the locking assembly further includes a fixing ring, a connecting rod, a limiting block, a pin hole, and a ratchet rack. The fixing ring is fixedly connected to the end face of the bracket near the U-shaped plate. A connecting rod is provided inside the connecting groove. A limiting block is fixedly connected to the bottom end of the connecting rod. The bottom end of the limiting block passes through the fixing ring and extends below the fixing ring. A pin hole is provided between the inner side of the connecting groove and the end of the connecting rod. A ratchet rack is fixedly connected to the top of the telescopic arm near the bracket. The ratchet rack is inclined towards the bracket. The top of the limiting block is inclined and matches the ratchet rack.
[0007] Preferably, the locking assembly further includes a bolt, a nut, a reset ring, and a reset spring. A bolt is provided inside the pin hole, and a nut is threaded to the end of the bolt. A reset ring is fixedly connected to the end of the telescopic end of the pull switch, and a reset spring is sleeved on the end of the telescopic end of the pull switch. The two ends of the reset spring abut against the top of the reset ring and the bottom of the U-shaped plate, respectively.
[0008] Preferably, the locking assembly further includes a drive shaft, a mounting ring, a cable reel, and a nylon ring. The mounting ring is fixedly connected to the outermost side of the telescopic arm, and the drive shaft is rotatably connected to the outermost side of the telescopic arm. The end of the drive shaft away from the telescopic arm passes through the mounting ring and is fixedly connected to the cable reel. The side of the cable reel opposite to the telescopic arm is fixedly connected to the nylon ring.
[0009] Preferably, the locking assembly further includes a fixing plate, a first stall sensor, a first iron plate, a housing, and a controller. The fixing plate is fixedly connected to the outer side of the mounting ring near the bottom. Two first stall sensors are symmetrically arranged on one side of the fixing plate. Several evenly distributed first iron plates are fixedly connected to the end face of the nylon ring opposite to the telescopic arm. The first iron plates match the first stall sensors. The housing is fixedly connected to the bottom of the telescopic arm near the cable rewinder. The controller is installed on the inner side of the housing. The two first stall sensors are electrically connected to the controller, and the controller is electrically connected to the pull switch.
[0010] Preferably, the dual safety mechanism includes a horizontal plate, a second stall sensor, and a second iron plate. The horizontal plate is fixedly connected to the end face of the U-shaped plate away from the bracket. The second stall sensor is installed at the bottom of the horizontal plate. The top of the ratchet rack is fixedly connected to a uniformly distributed second iron plate. The second iron plate matches the second stall sensor. The second stall sensor is electrically connected to the controller.
[0011] Preferably, a fixing frame is fixedly connected to one side of each of the telescopic arms, and a double-outlet wire reel is installed on one side of the fixing frame. One end of the double-outlet wire reel is electrically connected to an adjacent double-outlet wire reel, and the other end is electrically connected to an adjacent second stall sensor.
[0012] Compared with the prior art, the beneficial effects of the present invention are: By coordinating the telescopic boom, bracket, pull switch, limit block, ratchet rack, and controller, the telescopic boom can drive the cable rewinder and the first iron plate to rotate via the drive shaft during extension and retraction. This allows the first stall sensor to detect the speed of the cable rewinder. If the speed of the cable rewinder exceeds a predetermined value, the controller will close the pull switch, causing the return spring to push the limit block to engage with the ratchet rack, thus preventing the telescopic boom from retracting further. This effectively solves the problems of hydraulic leakage, valve core jamming, and seal failure, which would cause the anti-stall function to fail simultaneously, making it impossible to lock the boom. Additionally, this type of device is complex in structure and inconvenient to operate and maintain. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a bottom view of the telescopic arm structure in this invention; Figure 3 This is a schematic diagram showing the position distribution of the first stall sensor in this invention; Figure 4 This is a schematic diagram of the nylon ring structure in this invention; Figure 5 This is a schematic diagram of the support structure in this invention; Figure 6 This is a schematic diagram of the structure of the fixing ring in this invention; Figure 7 This is a schematic diagram of the limiting block in this invention; Figure 8 This is a schematic diagram illustrating the working principle of the first stall sensor in this invention.
[0015] Explanation of symbols in the diagram: 1. Telescopic arm; 2. Bracket; 3. U-shaped plate; 4. Pull-pull switch; 5. Connecting groove; 6. Fixing ring; 7. Connecting rod; 8. Limiting block; 9. Pin hole; 10. Fixing frame; 11. Bolt; 12. Nut; 13. Reset ring; 14. Reset spring; 15. Ratchet rack; 16. Drive shaft; 17. Mounting ring; 18. Cable reel; 19. Nylon ring; 20. Fixing plate; 21. First stall sensor; 22. First iron plate; 23. Horizontal plate; 24. Second stall sensor; 25. Second iron plate; 26. Housing; 27. Controller; 28. Dual-outlet cable reel. Detailed Implementation
[0016] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.
[0017] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0018] like Figures 1-8 As shown, the present invention provides a safety locking structure for preventing the boom of an aerial work platform from stalling, including a telescopic boom 1, wherein several telescopic booms 1 are provided, the size of the several telescopic booms 1 decreasing sequentially and connected to each other, and brackets 2 are fixedly connected to the end face of the several telescopic booms 1 near the top; a locking component is located at the top of the telescopic boom 1, and the locking component can lock the telescopic boom 1 when it stalls, and the locking component also includes a double safety mechanism, which is used in conjunction with the locking component.
[0019] like Figures 5-8 As shown, the locking assembly includes a U-shaped plate 3, a pull switch 4, and a connecting groove 5. The U-shaped plate 3 is fixedly connected to the end face of the bracket 2 away from the telescopic arm 1. The bottom of the U-shaped plate 3 is closed. The pull switch 4 is installed at the bottom of the inner cavity of the U-shaped plate 3. The telescopic end of the pull switch 4 passes through the U-shaped plate 3 and is slidably connected to the U-shaped plate 3. The telescopic end of the pull switch 4 has a connecting groove 5.
[0020] Furthermore, in this embodiment, the locking assembly also includes a fixing ring 6, a connecting rod 7, a limiting block 8, a pin hole 9, and a ratchet rack 15. The fixing ring 6 is fixedly connected to the end face of the bracket 2 near the U-shaped plate 3. The connecting rod 7 is provided inside the connecting groove 5. The bottom end of the connecting rod 7 is fixedly connected to the limiting block 8. The bottom end of the limiting block 8 passes through the fixing ring 6 and extends below the fixing ring 6. A pin hole 9 is provided between the inner side of the connecting groove 5 and the end of the connecting rod 7. The top of the telescopic arm 1 is fixedly connected to the ratchet rack 15 near the bracket 2. The ratchet rack 15 is inclined towards the bracket 2. The top of the limiting block 8 is inclined and matches the ratchet rack 15. Furthermore, in this embodiment, the locking assembly also includes a bolt 11, a nut 12, a reset ring 13, and a reset spring 14. The bolt 11 is provided inside the pin hole 9, and the end of the bolt 11 is threadedly connected to the nut 12. The end of the extension end of the pull switch 4 is fixedly connected to the reset ring 13, and the end of the extension end of the pull switch 4 is sleeved with the reset spring 14. The two ends of the reset spring 14 abut against the top of the reset ring 13 and the bottom of the U-shaped plate 3, respectively.
[0021] Furthermore, in this embodiment, the locking assembly also includes a drive shaft 16, a mounting ring 17, a cable reel 18, and a nylon ring 19. The mounting ring 17 is fixedly connected to one side of the outermost telescopic arm 1, and the drive shaft 16 is rotatably connected to one side of the outermost telescopic arm 1. The end of the drive shaft 16 away from the telescopic arm 1 passes through the mounting ring 17 and is fixedly connected to the cable reel 18. The nylon ring 19 is fixedly connected to the side of the cable reel 18 opposite to the telescopic arm 1.
[0022] Furthermore, in this embodiment, the locking assembly also includes a fixing plate 20, a first stall sensor 21, a first iron plate 22, a housing 26, and a controller 27. The fixing plate 20 is fixedly connected to the outer side of the mounting ring 17 near the bottom. Two first stall sensors 21 are symmetrically opened on one side of the fixing plate 20. Several evenly distributed first iron plates 22 are fixedly connected to the end face of the nylon ring 19 opposite to the telescopic arm 1. The first iron plates 22 are matched with the first stall sensors 21. The housing 26 is fixedly connected to the bottom of the telescopic arm 1 near the cable reel 18. The controller 27 is installed on the inner side of the housing 26. The two first stall sensors 21 are electrically connected to the controller 27 respectively. The controller 27 is electrically connected to the pull switch 4.
[0023] In the technical solution adopted in this embodiment, the bottom of the U-shaped plate 3 is closed, which can effectively protect the pull switch 4 installed inside. The telescopic end of the pull switch 4 passes through the U-shaped plate 3 and is slidably connected, which can realize the flexible extension and retraction of the telescopic end and ensure the timely locking action. At the same time, the sliding connection structure can reduce the friction during the extension and retraction process, reduce component wear, and extend the service life of the pull switch 4. The connecting groove 5 provides a suitable space for the installation of the connecting rod 7, realizing the quick docking of the pull switch 4 and the connecting rod 7, which facilitates the later installation, disassembly and maintenance, and improves the maintenance convenience of the device.
[0024] In the technical solution adopted in this embodiment, the fixing ring 6 can limit and guide the connecting rod 7, ensuring that the connecting rod 7 always remains vertical during movement, avoiding the connection rod 7 from deviating and causing the locking action to fail, thus ensuring the reliability of the locking structure. The top of the limiting block 8 is inclined and matches the ratchet rack 15, which can realize quick locking when the telescopic arm 1 stalls. The inclined structure can increase the contact area between the limiting block 8 and the ratchet rack 15, improve the locking force, prevent loosening or slippage after locking, and ensure that the telescopic arm 1 can be stably locked in the current position. The pin hole 9 is used in conjunction with the bolt 11 and nut 12 to avoid the connection between the two from being loose and causing abnormal locking action. At the same time, the detachable connection of the bolt 11 and nut 12 facilitates the replacement and maintenance of components later. The ratchet rack 15 is inclined towards the bracket 2, which, in conjunction with the inclined structure of the limiting block 8, can further improve the stability of locking and prevent the telescopic arm 1 from continuing to fall due to gravity after locking.
[0025] like Figures 1-7 As shown, the dual safety mechanism includes a horizontal plate 23, a second stall sensor 24, and a second iron plate 25. The horizontal plate 23 is fixedly connected to the end face of the U-shaped plate 3 away from the bracket 2. The second stall sensor 24 is installed at the bottom of the horizontal plate 23. The second iron plate 25 is fixedly connected to the top of the ratchet rack 15 and is evenly distributed. The second iron plate 25 matches the second stall sensor 24. The second stall sensor 24 is electrically connected to the controller 27.
[0026] In the technical solution adopted in this embodiment, the horizontal plate 23 provides a stable mounting support for the second stall sensor 24, ensuring that the second stall sensor 24 can be accurately aligned with the second iron piece 25 on the ratchet rack 15, thereby improving the detection accuracy. The second stall sensor 24 and the second iron piece 25 are matched, which can perform secondary detection on the movement state of the telescopic arm 1, forming a dual detection mechanism with the first stall sensor 21, further improving the reliability of stall detection, avoiding locking failure due to a single detection link failure, forming a double insurance, and minimizing the risk of the telescopic arm 1 stalling. The second stall sensor 24 is electrically connected to the controller 27, which can quickly transmit the detected stall signal to the controller 27, ensuring that the controller 27 can trigger the locking action in time, and ensuring the timeliness and effectiveness of the locking.
[0027] Furthermore, in this embodiment, a fixing frame 10 is fixedly connected to one side of each of the several telescopic arms 1. A double-outlet wire reel 28 is installed on one side of the fixing frame 10. One end of the double-outlet wire reel 28 is electrically connected to an adjacent double-outlet wire reel 28, and the other end is electrically connected to an adjacent second stall sensor 24.
[0028] In the technical solution adopted in this embodiment, the fixing frame 10 provides stable installation support for the double-outlet wire reel 28, ensuring that the double-outlet wire reel 28 will not loosen or shift during the movement of the telescopic arm 1. One end of the double-outlet wire reel 28 is electrically connected to the adjacent double-outlet wire reel 28, and the other end is electrically connected to the adjacent second stall sensor 24. This allows for the orderly wiring of multiple second stall sensors 24, avoiding messy wiring. At the same time, it can adapt to the telescopic movement of the telescopic arm 1, realize the synchronous winding and unwinding of the cable, prevent circuit failures caused by cable pulling or breakage, ensure the stable connection of the electrical system, and ensure the normal operation of the double safety mechanism.
[0029] The working principle of this invention is as follows: First, the controller 27 is installed on the telescopic arm 1 and debugged to match the telescopic arm 1. The cable reel 18 is fixedly connected to the transmission component inside the telescopic arm 1. When multiple telescopic arms 1 extend and retract, they will drive the cable reel 18 to rotate. The internal transmission component is common knowledge among those skilled in the art, so it will not be described in detail in this technical solution. After debugging, the extension end of the pull switch 4 is in the retracted state, so that the limit block 8 disengages from the ratchet rack 15.
[0030] The nylon ring 19 and the first iron plate 22 installed on the cable retractor 18 cooperate with the first stall sensor 21 to monitor the retraction speed of the aerial work platform telescopic boom 1 in real time. When the cable retractor 18 rotates, the first iron plate 22 triggers the first stall sensor 21 to generate a pulse signal. The controller 27 calculates the boom retraction speed based on this and compares it with a preset safety threshold. Once the boom retraction speed abnormally exceeds the threshold, it is immediately determined to be a rope breakage fault, triggering an audible and visual alarm and outputting an emergency stop signal. At this time, the controller 27 transmits the signal to the pull switch 4, causing the pull switch 4 to close. The rebound force of the synchronous return spring 14 pushes the return ring 13 and the connecting rod 7 to descend, so that the limit block 8 engages with the ratchet rack 15, thereby locking multiple telescopic booms 1 and preventing the telescopic booms 1 from descending further, thus protecting the workers. In this way, even if the electrical system is powered off, there will be no rapid descent, which can effectively improve the safety of use.
[0031] To improve safety, the second stall sensor 24 works in conjunction with the second iron plate 25 on the ratchet rack 15 to detect stall of the telescopic arm 1. When the telescopic arm 1 stalls, it transmits a signal to the controller 27, which then controls the suction switch 4 to close. When the suction switch 4 closes, it loses the force pulling the limit block 8, allowing the reset spring 14 to push the limit block 8 to engage with the ratchet rack 15 immediately. This double safety feature effectively improves ease of use.
[0032] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0033] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A safety locking structure for preventing stalling of the boom of an aerial work platform, comprising a telescopic boom (1), characterized in that, The telescopic arm (1) is provided in several ways. The size of the telescopic arm (1) decreases sequentially and is connected to each other. The end face of the telescopic arm (1) is fixedly connected to the top with a bracket (2). The locking assembly is located at the top of the telescopic boom (1) and is capable of locking the telescopic boom (1) in the event of stall. The locking assembly also includes a double safety mechanism that works in conjunction with the locking assembly.
2. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 1, characterized in that, The locking assembly includes a U-shaped plate (3), a pull switch (4), and a connecting groove (5). The U-shaped plate (3) is fixedly connected to the end face of the bracket (2) away from the telescopic arm (1). The bottom of the U-shaped plate (3) is closed. The pull switch (4) is installed at the bottom of the inner cavity of the U-shaped plate (3). The telescopic end of the pull switch (4) passes through the U-shaped plate (3) and is slidably connected to the U-shaped plate (3). The telescopic end of the pull switch (4) is provided with a connecting groove (5).
3. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 2, characterized in that, The locking assembly also includes a fixing ring (6), a connecting rod (7), a limiting block (8), a pin hole (9), and a ratchet rack (15). The fixing ring (6) is fixedly connected to the end face of the bracket (2) near the U-shaped plate (3). The connecting rod (7) is provided inside the connecting groove (5). The limiting block (8) is fixedly connected to the bottom end of the connecting rod (7). The bottom end of the limiting block (8) passes through the fixing ring (6) and extends to the bottom of the fixing ring (6). A pin hole (9) is provided between the inner side of the connecting groove (5) and the end of the connecting rod (7). The ratchet rack (15) is fixedly connected to the top of the telescopic arm (1) near the bracket (2). The ratchet rack (15) is inclined toward the bracket (2). The top of the limiting block (8) is inclined and matches the ratchet rack (15).
4. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 3, characterized in that, The locking assembly also includes a bolt (11), a nut (12), a reset ring (13), and a reset spring (14). The bolt (11) is provided inside the pin hole (9), and the end of the bolt (11) is threaded with a nut (12). The end of the extension end of the pull switch (4) is fixedly connected with a reset ring (13), and the end of the extension end of the pull switch (4) is fitted with a reset spring (14). The two ends of the reset spring (14) abut against the top of the reset ring (13) and the bottom of the U-shaped plate (3), respectively.
5. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 1, characterized in that, The locking assembly also includes a drive shaft (16), a mounting ring (17), a cable reel (18), and a nylon ring (19). The mounting ring (17) is fixedly connected to one side of the outermost telescopic arm (1), and the drive shaft (16) is rotatably connected to one side of the outermost telescopic arm (1). The end of the drive shaft (16) away from the telescopic arm (1) passes through the mounting ring (17) and is fixedly connected to the cable reel (18). The nylon ring (19) is fixedly connected to the side of the cable reel (18) opposite to the telescopic arm (1).
6. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 5, characterized in that, The locking assembly also includes a fixing plate (20), a first stall sensor (21), a first iron plate (22), a housing (26), and a controller (27). The fixing plate (20) is fixedly connected to the outer side of the mounting ring (17) near the bottom. Two first stall sensors (21) are symmetrically opened on one side of the fixing plate (20). Several evenly distributed first iron plates (22) are fixedly connected to the end face of the nylon ring (19) opposite to the telescopic arm (1). The first iron plates (22) are matched with the first stall sensors (21). The housing (26) is fixedly connected to the bottom of the telescopic arm (1) near the cable reel (18). The controller (27) is installed on the inner side of the housing (26). The two first stall sensors (21) are electrically connected to the controller (27) respectively. The controller (27) is electrically connected to the pull switch (4).
7. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 3, characterized in that, The dual safety mechanism includes a horizontal plate (23), a second stall sensor (24), and a second iron plate (25). The horizontal plate (23) is fixedly connected to the end face of the U-shaped plate (3) away from the bracket (2). The second stall sensor (24) is installed at the bottom of the horizontal plate (23). The second iron plate (25) is fixedly connected to the top of the ratchet rack (15). The second iron plate (25) matches the second stall sensor (24). The second stall sensor (24) is electrically connected to the controller (27).
8. The safety locking structure for preventing the boom of an aerial work platform from stalling according to claim 7, characterized in that, A fixed frame (10) is fixedly connected to one side of each of the telescopic arms (1). A double-outlet wire reel (28) is installed on one side of the fixed frame (10). One end of the double-outlet wire reel (28) is electrically connected to an adjacent double-outlet wire reel (28), and the other end is electrically connected to an adjacent second stall sensor (24).