Grounding switch and handcart protection locking device and use method

Abstract

The grounding switch and handcart protection locking device comprises a handcart arranged in a cabinet body and a main shaft used for controlling opening and closing, the handcart comprises a chassis movably installed in the cabinet body, the cabinet body is internally provided with a locking assembly linked with the chassis, the locking assembly comprises a shell, and the shell is internally provided with a grounding switch. A pressing arm linked with the chassis is rotatably arranged in the shell, the other end of the pressing arm is linked with a connecting rod, a limiting part is fixedly arranged on the main shaft, and the connecting rod is driven by the pressing arm to be locked with the limiting part so that the main shaft cannot rotate when the handcart moves to a station position. And when the handcart is at the test position, the connecting rod is unlocked from the limiting part, so that the main shaft can rotate.

Description

Technical Field

[0001] This invention relates to a grounding switch and a handcart protection interlocking device and its usage method, belonging to the field of handcart protection devices. Background Technology

[0002] High-voltage switchgear is an electrical device whose main function is to open, close, control, and protect electrical equipment during power generation, transmission, distribution, and energy conversion in a power system. A grounding trolley is essential equipment for the maintenance of high-voltage switchgear. Its primary function is to reliably ground the system's main busbar, ensuring personal safety during maintenance. When maintaining a high-voltage switchgear, first, the system's main busbar is de-energized. Then, the original circuit breaker in the switchgear to be maintained is removed. Next, the grounding trolley is pushed into the switchgear to ground the main busbar before maintenance begins.

[0003] Traditional switchgear typically uses mechanical interlocking mechanisms located on the outside of the cabinet. When a circuit breaker is manually inserted into the cabinet, the grounding switch cannot be operated; the circuit breaker is inserted to lock the grounding switch's operating handle. However, current switchgear systems have optimized this structure during the intelligentization process, replacing it with electrical control. But electrical control is easily overlooked and cannot guarantee the safety of the switchgear, potentially leading to problems such as explosions. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a grounding switch and handcart protection interlocking device and its usage method.

[0005] A grounding switch and handcart protection interlocking device includes a handcart installed inside a cabinet and a main shaft for controlling the opening and closing of the switch. The handcart includes a chassis movably installed inside the cabinet. An interlocking assembly linked to the chassis is provided inside the cabinet. The interlocking assembly includes a housing. An actuating arm linked to the chassis is rotatably installed inside the housing. A connecting rod is linked to the other end of the actuating arm. A limiting part is fixedly provided on the main shaft. When the handcart moves to the working position, the connecting rod is driven by the actuating arm and locked by the limiting part, preventing the main shaft from rotating. When the handcart is in the test position, the connecting rod is unlocked from the limiting part, allowing the main shaft to rotate.

[0006] Through the above technical solution, by installing an interlocking component linked to the circuit breaker trolley inside the cabinet, the main shaft of the grounding switch is mechanically locked by the connecting rod and the limiting part when the trolley is in the working position, preventing accidental rotation of the main shaft; when the trolley is in the test position, the lock is automatically released, allowing the grounding switch to operate normally, thereby achieving mechanical interlocking between the trolley position and the grounding switch operating state. When the circuit breaker trolley is not in the correct position, this device can automatically prevent the operation of the grounding switch, avoiding phase-to-phase short circuits or accidental closing caused by misoperation, ensuring the safety of operators and equipment.

[0007] Preferably, a reset spring for resetting the position of the push arm is sleeved on the connecting rod.

[0008] By employing the aforementioned technical solution, and by installing a return spring on the connecting rod to reset the position of the push arm, the spring force automatically returns the push arm to its initial position after the handcart leaves the push arm's operating position. This ensures that the locking assembly returns to the lockable state after each action, guaranteeing the smooth execution of the next locking action. The push arm's automatic reset after the handcart's withdrawal ensures the locking assembly returns to its original state, preventing mechanism jamming or locking malfunctions, and improving the reliability and durability of the locking structure.

[0009] Furthermore, the outer casing is provided with a mounting base, one end of the limiting rod passes through the mounting base and is linked with the limiting part, and the other end is linked with the pressing arm, and one end of the reset spring abuts against the mounting base.

[0010] Through the above technical solution, the limiting rod can reciprocate along a fixed trajectory under the guidance of the mounting base, thereby ensuring that the transmission direction between the connecting rod, the push arm, and the limiting part is consistent, and avoiding deviation or jamming. One end of the return spring abuts against the mounting base, and can automatically generate elastic force after the handcart leaves the push arm's position, returning the push arm to its initial position.

[0011] Preferably, the limiting part includes a main body fixedly sleeved on the main shaft, a limiting block protruding from the main body, and the connecting rod being driven by the push arm to move above the limiting block when the handcart moves to the working position to form a limiting connection with it, thus hindering the rotation of the main shaft. When the handcart is in the test position, the connecting rod is removed from the position above the limiting block, and the main shaft can rotate.

[0012] With the above technical solution, when the handcart moves to the working position, the connecting rod moves above the limit stop under the drive of the push arm, forming a limit connection with it, thereby preventing the main shaft from continuing to rotate and achieving mechanical locking. When the handcart moves to the test position, the connecting rod automatically retracts above the limit stop, allowing the main shaft to return to a rotatable state, facilitating the operation of the grounding switch.

[0013] Preferably, the system includes a control circuit. A micro-position switch electrically connected to the control circuit is provided within the housing. The control circuit drives the spindle drive motor and the micro-position switch. The normally closed contact of the micro-position switch is connected in series in the control circuit of the drive motor. When the trolley is in the test position, the micro-position switch closes to allow the drive motor to drive the spindle to rotate. When the trolley leaves the test position, the micro-position switch changes from normally closed to normally open, cutting off the power supply circuit to the drive motor, thus de-energizing the drive motor and preventing it from operating.

[0014] The above technical solution enables automatic identification of the trolley position under electric control, achieving electrical forced interlocking between the grounding switch and the trolley position. This effectively prevents the circuit breaker or grounding switch from being misoperated in unsafe conditions, thus avoiding equipment damage and personal injury accidents. By incorporating a micro-position switch into the interlocking structure, synchronous output of electrical interlocking signals can be achieved, enabling the device to achieve both mechanical interlocking and linkage with the electrical control system, forming an intelligent anti-misoperation interlocking system. Automatic grounding switch interlocking control is performed based on the trolley position, and the operating status can be fed back through electrical indicators, enabling visualization of equipment status. This facilitates operation monitoring and remote management, improving the intelligence level of the high-voltage switchgear.

[0015] Furthermore, the control circuit also includes an overcurrent protection device for cutting off the power supply to the drive motor and generating a protection signal when an abnormal overcurrent is detected in the drive motor. The overcurrent protection device includes a current transformer and an overcurrent relay.

[0016] The above technical solution, by incorporating an overcurrent protection device in the control circuit, activates immediately when the drive motor's operating current exceeds a set threshold, cutting off the power supply to the drive motor and outputting a protection signal. This allows for timely power cut-off in case of overload caused by mechanical jamming, spindle blockage, or abnormal locking of the drive motor, preventing motor burnout or mechanical damage. Simultaneously, it outputs a protection signal for alarm or interlock shutdown, significantly improving the system's safety, reliability, and fault protection capabilities.

[0017] Furthermore, the micro-position switch has an on-off structure, including a normally closed contact and a normally open contact. The normally closed contact is connected in series in the drive motor control circuit to cut off the motor power supply; the normally open contact is connected to an indicator light or alarm circuit to output a status signal or alarm signal when the handcart leaves the test position.

[0018] The above technical solution integrates motor control and alarm indication functions into the same component, realizing synchronous output of interlocking control and status prompts. This prevents misoperation and improves the intelligence and safety of the device. While achieving electrical forced interlocking, it can provide real-time prompts on the position status of the handcart, avoiding misoperation due to the operator not noticing the position of the handcart. This significantly improves the safety and visual management capabilities of the device.

[0019] Furthermore, the push arm is bent and includes a trigger drive plate. One end of the trigger drive plate is provided with a roller that cooperates with the chassis, and the other end is connected to a drive crank arm for connecting with the connecting rod. When the chassis of the handcart moves away from the test position, it pushes the roller down, causing the other end of the push arm to drive the connecting rod to move and trigger the micro position switch.

[0020] This technical solution enables the smooth and accurate conversion of the mechanical movement of the trolley into action signals for the locking mechanism, achieving synchronous linkage between mechanical position changes and electrical control. The use of roller contact effectively reduces frictional resistance and wear, preventing jamming or deformation caused by forceful pushing, ensuring smooth and reliable operation of the locking mechanism. The bending arrangement of the boom allows for flexible adjustment of the installation angle, position, and force transmission direction according to the cabinet space, resulting in a more compact layout and a more rational transmission path, further enhancing the sensitivity and reliability of the locking mechanism.

[0021] Furthermore, the trigger drive plate is L-shaped, with a number of first adjustment holes arranged at intervals on one side wall. The trigger drive plate is bolted to the drive crank arm through the first adjustment holes, allowing the roller to be adjusted back and forth. A number of second adjustment holes are arranged at intervals on the other side wall. The trigger drive plate abuts against the bottom surface of the drive crank arm through the installation bolts in the second adjustment holes, forming a circumferential rotation limit on the trigger drive plate.

[0022] This technical solution, by setting a first adjustable hole for front and rear movement and a second adjustable hole for limiting on the L-shaped trigger drive plate, enables the adjustment and limiting of the roller position and rotation angle, thereby improving the installation adaptability, action accuracy and operation stability of the device.

[0023] This invention also provides a method for using a grounding switch and a handcart protection interlocking device. Using any of the above-mentioned grounding switch and handcart protection interlocking devices, when the handcart is in the test position, the micro-position switch is normally closed, the control circuit is connected, and at this time the connecting rod and the limiting part are unlocked, and the drive motor can drive the main shaft to rotate. When the handcart leaves the test position, the micro-position switch is disconnected, the control circuit of the drive motor is cut off, the drive motor loses power and cannot drive the main shaft to rotate, the micro-position switch outputs a status signal, the chassis of the handcart drives the push arm, and the push arm drives the connecting rod to move above the limiting block to form a limiting connection with it, thus preventing the external drive main shaft from rotating.

[0024] The above technical solution effectively achieves the linkage between electrical and mechanical interlocking. Through the cooperation of micro-position switches and limit devices, misoperation caused by incorrect placement of the handcart is avoided, greatly improving the safety, intelligence level, and operational reliability of the equipment. This method, through an interlocking mechanism composed of micro-position switches, control circuits, connecting rods, and limit blocks, automatically controls the start and stop of the grounding switch, reducing human intervention and preventing equipment operation errors. The status signal output of the micro-position switches not only makes the operation process more intelligent but also facilitates fault diagnosis and remote monitoring.

[0025] The beneficial effects of this invention are as follows: By installing a locking component linked to the circuit breaker trolley inside the cabinet, the main shaft of the grounding switch is mechanically locked by the connecting rod and the limiting part when the trolley is in the working position, preventing accidental rotation of the main shaft; when the trolley is in the test position, the locking is automatically released, allowing the grounding switch to operate normally, thereby achieving mechanical interlocking between the trolley position and the grounding switch operating state. When the circuit breaker trolley is not in the correct position, this device can automatically prevent the operation of the grounding switch, avoiding phase-to-phase short circuits or accidental closing caused by misoperation, ensuring the safety of operators and equipment. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0027] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention with part of the cabinet removed; Figure 3 yes Figure 2 A structural diagram from another perspective; Figure 4 This is a schematic diagram of the structure for unlocking the locking assembly and the limiting part; Figure 5 A structural schematic diagram of the locking assembly from another perspective; Figure 6 A schematic diagram showing the structure of the interlocking assembly without the mounting base; Figure 7 A schematic diagram of the locking mechanism and the limiting part being locked together; Figure 8 This is the circuit schematic for the control circuit; In the diagram, 1. Handcart; 11. Chassis; 2. Main shaft; 3. Limiting part; 31. Main body; 32. Limiting block; 4. Locking assembly; 41. Housing; 42. Pressing arm; 421. Roller; 422. Trigger drive plate; 423. Drive crank arm; 424. First adjustment hole; 425. Second adjustment hole; 43. Connecting rod; 44. Return spring; 46. Mounting base; 47. Micro position switch. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0030] The directional and positional terms used in this invention, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustrating and understanding this invention, and not for limiting the scope of protection of this invention.

[0031] like Figure 1-8 The diagram illustrates an embodiment of a grounding switch and handcart protection interlocking device according to the present invention. It includes a handcart 1 housed within a cabinet and a main shaft 2 for controlling the opening and closing of the switch. The handcart 1 includes a chassis 11 movably mounted within the cabinet. An interlocking assembly 4, linked to the chassis 11, is provided within the cabinet. The interlocking assembly 4 includes a housing 41. A push-button arm 42, linked to the chassis 11, is rotatably mounted within the housing 41. A connecting rod 43 is linked to the other end of the push-button arm 42. A limiting part 3 is fixedly mounted on the main shaft 2. When the handcart 1 moves to the working position, the connecting rod 43 is driven by the push-button arm 42 and locked to the limiting part 3, preventing the main shaft 2 from rotating. When the handcart 1 is in the test position, the connecting rod 43 unlocks from the limiting part 3, allowing the main shaft 2 to rotate.

[0032] Through the above technical solution, by installing a locking component 4 linked to the handcart 1 inside the cabinet, the main shaft 2 of the grounding switch is mechanically locked by the connecting rod 43 and the limiting part 3 when the handcart 1 is in the working position, preventing the main shaft 2 from rotating accidentally; when the handcart 1 is in the test position, the locking is automatically released, allowing the grounding switch to operate normally, thereby achieving mechanical interlocking between the position of the handcart 1 and the operating state of the grounding switch. When the circuit breaker handcart 1 is not in the correct position, this device can automatically prevent the operation of the grounding switch, avoiding phase-to-phase short circuits or accidental closing caused by misoperation, ensuring the safety of operators and equipment.

[0033] A reset spring 44 is fitted on the connecting rod 43 to reset the position of the push arm 42.

[0034] Through the above technical solution, by setting a return spring 44 on the connecting rod 43 to reset the position of the push arm 42, the push arm 42 can be automatically reset to its initial position by the elastic force of the return spring 44 after the handcart 1 leaves the operating position of the push arm 42. This ensures that the locking assembly 4 can return to the lockable state after each action, guaranteeing the smooth execution of the next locking action. The push arm 42 can automatically reset after the handcart 1 is withdrawn, ensuring that the locking assembly 4 returns to its original state, preventing the mechanism from jamming or locking abnormalities, and improving the reliability and durability of the locking structure.

[0035] The housing 41 is provided with a mounting base 46. One end of the limiting rod passes through the mounting base 46 and is linked with the limiting part 3, and the other end is linked with the pressing arm 42. One end of the reset spring 44 abuts against the mounting base 46.

[0036] Through the above technical solution, the limiting rod can reciprocate along a fixed trajectory under the guidance of the mounting base 46, thereby ensuring that the transmission direction between the connecting rod 43, the push arm 42, and the limiting part 3 is consistent, and avoiding deviation or jamming. One end of the return spring 44 abuts against the mounting base 46, and can automatically generate elastic force after the handcart 1 leaves the action position of the push arm 42, returning the push arm 42 to the initial position.

[0037] The limiting part 3 includes a main body 31 fixedly sleeved on the main shaft 2. A limiting block 32 protrudes from the main body 31. When the handcart 1 moves to the working position, the connecting rod 43 is driven by the push arm 42 to move above the limiting block 32 to form a limiting connection with it, thus preventing the main shaft 2 from rotating. When the handcart 1 is in the test position, the connecting rod 43 is removed from the position above the limiting block 32, and the main shaft 2 can rotate.

[0038] Through the above technical solution, when the handcart 1 moves to the working position, the connecting rod 43 moves above the limit stop 32 under the drive of the push arm 42, forming a limit connection with it, thereby preventing the main shaft 2 from continuing to rotate and achieving mechanical locking. When the handcart 1 moves to the test position, the connecting rod 43 automatically retracts above the limit stop 32, allowing the main shaft 2 to return to a rotatable state, facilitating the operation of the grounding switch.

[0039] Includes a control circuit. The housing 41 contains a micro position switch 47 electrically connected to the control circuit. The control circuit K is used to drive the drive motor M of the main shaft 2 and the micro position switch S. The normally closed contact of the micro position switch 47 is connected in series in the control circuit of the drive motor. When the handcart 1 is in the test position, the micro position switch 47 is closed to allow the drive motor to drive the main shaft 2 to rotate. When the handcart 1 leaves the test position, the micro position switch 47 changes from normally closed to normally open, cutting off the power supply circuit of the drive motor, thereby causing the drive motor to lose power and become unable to operate.

[0040] Through the above technical solution, the position of the handcart 1 can be automatically identified under electric control, realizing the electrical forced interlock between the grounding switch and the position of the handcart 1. This effectively prevents the circuit breaker or grounding switch from being misoperated in an unsafe state, thereby avoiding equipment damage and personal safety accidents. By incorporating a micro-position switch 47 into the interlocking structure, synchronous output of the electrical interlocking signal can be achieved, enabling the device to achieve both mechanical interlocking and linkage with the electrical control system, forming an intelligent anti-misoperation interlocking system. The grounding switch interlocking control is automatically performed based on the position of the handcart 1, and the operating status can be fed back through electrical indicators, realizing equipment status visualization, which is beneficial for operation monitoring and remote management, and improves the intelligence level of the high-voltage switchgear.

[0041] The control circuit also includes an overcurrent protection device OC for cutting off the power supply to the drive motor and generating a protection signal when an abnormal overcurrent is detected in the drive motor. The overcurrent protection device includes a current transformer and an overcurrent relay.

[0042] Through the above technical solution, by setting an overcurrent protection device in the control circuit, when the operating current of the drive motor is detected to exceed the set threshold, the overcurrent protection device immediately activates, cutting off the power supply circuit of the drive motor and outputting a protection signal. This enables timely power cut-off in case of overload caused by mechanical jamming, spindle blockage, or abnormal locking of the drive motor, preventing motor burnout or mechanical damage. Simultaneously, it outputs a protection signal for alarm or interlock shutdown, significantly improving the system's safety, reliability, and fault protection capabilities.

[0043] The micro position switch 47 has an on-off structure, including a normally closed contact and a normally open contact. The normally closed contact is connected in series in the drive motor control circuit to cut off the motor power supply. The normally open contact is connected to an indicator light or alarm circuit to output a status signal or alarm signal when the handcart 1 leaves the test position.

[0044] The above technical solution integrates motor control and alarm indication functions into the same component, realizing synchronous output of interlocking control and status prompts. This prevents misoperation and improves the intelligence and safety of the device. While achieving electrical forced interlocking, it can provide real-time prompts on the position status of the handcart 1, avoiding misoperation due to the operator not noticing the position of the handcart 1. This significantly improves the safety and visual management capabilities of the device.

[0045] The push arm 42 is bent and includes a trigger drive plate 422. One end of the trigger drive plate 422 is provided with a roller 421 that cooperates with the chassis 11, and the other end is connected to a drive crank arm 423 for connecting with the moving rod. When the chassis 11 of the handcart 1 moves away from the experimental position, the roller 421 is pushed down, causing the other end of the push arm 42 to drive the connecting rod 43 to move and trigger the micro position switch 47.

[0046] This technical solution enables the smooth and accurate conversion of the mechanical movement of the handcart 1 into the action signal of the locking mechanism, achieving synchronous linkage between mechanical position changes and electrical control. The use of rollers 421 for contact effectively reduces frictional resistance and wear, preventing jamming or deformation caused by forceful pushing, ensuring smooth and reliable operation of the locking mechanism. The bent arrangement of the boom 42 allows for flexible adjustment of the installation angle, position, and force transmission direction according to the cabinet space, resulting in a more compact layout and a more rational transmission path, further enhancing the sensitivity and reliability of the locking mechanism.

[0047] The trigger drive plate 422 is L-shaped, with a number of first adjustment holes 424 arranged at intervals on one side wall. The trigger drive plate 422 is bolted to the drive crank arm 423 through the first adjustment holes 424, so that the roller 421 can be adjusted back and forth. A number of second adjustment holes 425 are arranged at intervals on the other side wall. The trigger drive plate 422 is abutted against the bottom surface of the drive crank arm 423 through the bolts installed in the second adjustment holes 425, which forms a circumferential rotation limit for the trigger drive plate 422.

[0048] This technical solution, by setting a front-to-back adjustable first adjustment hole 424 and a limiting second adjustment hole 425 on the L-shaped trigger drive plate 422, enables the adjustment and limiting of the position and rotation angle of the roller 421, thereby improving the installation adaptability, action accuracy and operation stability of the device.

[0049] This invention also provides a method for using a grounding switch and a protective interlocking device for a handcart 1. Using any of the above-mentioned grounding switch and handcart 1 protective interlocking devices, when the handcart 1 is in the test position, the micro-position switch 47 is normally closed, the control circuit is connected, and at this time the connecting rod 43 and the limiting part 3 are unlocked, and the drive motor can drive the main shaft 2 to rotate. When the handcart 1 leaves the test position, the micro-position switch 47 is disconnected and changes to a normally open state, the control circuit of the drive motor is cut off, the drive motor loses power and cannot drive the main shaft 2 to rotate, the micro-position switch 47 is normally closed, and the output status signal indicates that the handcart has left the test position, the grounding switch cannot be closed, the chassis 11 of the handcart 1 drives the push arm 42, and the push arm 42 drives the connecting rod 43 to move above the limiting block 32 to form a limiting connection with it, thus preventing the external drive main shaft 2 from rotating.

[0050] The above technical solution effectively achieves the linkage between electrical and mechanical interlocking. Through the cooperation of the micro-position switch 47 and the limit device, misoperation caused by incorrect placement of the handcart 1 is avoided, greatly improving the equipment's safety, intelligence level, and operational reliability. This method, through the interlocking mechanism composed of the micro-position switch 47, control circuit, connecting rod 43, and limit stop 32, automatically controls the start and stop of the grounding switch, reducing human intervention and preventing equipment operation errors. The status signal output of the micro-position switch 47 not only makes the operation process more intelligent but also facilitates fault diagnosis and remote monitoring.

[0051] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

[0052] While the invention has been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A ground switch and trolley protection interlock device, characterized in that: The application relates to a handcart and a main shaft for controlling opening and closing, wherein the handcart comprises a chassis movably arranged in a cabinet, and a locking assembly arranged in the cabinet and connected with the chassis; the locking assembly comprises a shell, a pressing arm rotatably arranged in the shell and connected with the chassis, and a connecting rod connected with the other end of the pressing arm; a limiting part is fixedly arranged on the main shaft; when the handcart moves to a working position, the connecting rod is driven by the pressing arm and locked with the limiting part, so that the main shaft cannot rotate; when the handcart moves to a test position, the connecting rod is unlocked with the limiting part, so that the main shaft can rotate.

2. The ground switch and trolley protection lockout device of claim 1, wherein: A reset spring is arranged on the connecting rod and used for resetting the position of the pressing arm.

3. The ground switch and trolley protection lockout device of claim 2, wherein: A mounting seat is arranged on the shell; one end of the limiting rod is connected with the limiting part through the mounting seat, and the other end is connected with the pressing arm; and one end of the reset spring is abutted with the mounting seat.

4. The ground switch and trolley protection lockout device of claim 1, wherein: The limiting part comprises a main body fixedly arranged on the main shaft, and a limiting block protruding from the main body; when the handcart moves to the working position, the connecting rod is driven by the pressing arm and moves to the position above the limiting block, so that the connecting rod is limited with the limiting block and the main shaft cannot rotate; when the handcart moves to the test position, the connecting rod is out of the position above the limiting block, so that the main shaft can rotate.

5. The ground switch and trolley protection lockout device of claim 1, wherein: A control circuit is arranged in the shell and electrically connected with a micro-motion position switch which is triggered by the action of the pressing arm; the control circuit is used for driving a driving motor of the main shaft and the micro-motion position switch; the normally closed contact of the micro-motion position switch is arranged in series in a control loop of the driving motor; when the handcart is in the test position, the micro-motion position switch is closed to allow the driving motor to drive the main shaft to rotate; when the handcart is out of the test position, the micro-motion position switch is converted from the normally closed state to the normally open state, so that the power supply loop of the driving motor is cut off, and the driving motor is de-energized and cannot act.

6. The ground switch and trolley protection lockout device of claim 5, wherein: The control circuit further comprises an overcurrent protection device used for cutting off the power supply of the driving motor and generating a protection signal when the driving motor is detected to have an abnormal overcurrent; the overcurrent protection device comprises a current transformer and an overcurrent relay.

7. The ground switch and trolley protection lockout device of claim 5, wherein: The micro-motion position switch is of one-close-one-open structure and comprises a normally closed contact and a normally open contact; the normally closed contact is arranged in series in the control loop of the driving motor and used for cutting off the power supply of the motor; and the normally open contact is connected to an indicating lamp or an alarm circuit and used for outputting a state signal or an alarm signal when the handcart is out of the test position.

8. The ground switch and trolley protection lockout device of claim 5, wherein: The pressing arm is arranged in a bending mode and comprises a trigger driving plate; one end of the trigger driving plate is provided with a roller matched with the chassis, and the other end of the trigger driving plate is connected with a driving crank arm used for connecting with the connecting rod; when the chassis of the handcart moves away from the test position, the roller is pushed downward to drive the other end of the pressing arm to move and trigger the micro-motion position switch.

9. The ground switch and trolley protection lockout device of claim 8, wherein: The trigger driving plate is arranged in an L mode; a plurality of first adjusting holes are arranged on one side wall in an interval mode; the trigger driving plate is bolted with the driving crank arm through the first adjusting holes, so that the roller can be adjusted forward and backward; a plurality of second adjusting holes are arranged on the other side wall in an interval mode; the trigger driving plate is abutted with the bottom surface of the driving crank arm through the mounting bolt in the second adjusting hole, so that the circumferential rotation of the trigger driving plate is limited.

10. A method of using a grounding switch and trolley protection lockout device, comprising: The ground switch and handcart protection locking device of any one of claims 1-7 is used, when the handcart is in the test position, the micro-motion position switch is in the normally closed state, the control circuit is connected, at this time the connecting rod and the limiting part are in the unlocked state, and the driving motor can drive the main shaft to rotate; when the handcart leaves the test position, the micro-motion position switch is disconnected, the control circuit of the driving motor is cut off, the driving motor loses power and cannot drive the main shaft to rotate, the micro-motion position switch outputs a state signal, the chassis of the handcart drives the pressing arm, and the pressing arm drives the connecting rod to move to the upper side of the limiting block to form a limiting connection, thereby preventing external driving of the main shaft to rotate.

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