High-speed circuit breaker gap detection device

Abstract

The utility model provides a high-speed circuit breaker gap detection device, which comprises a main positioning block, an auxiliary positioning block, a main shaft and an operation auxiliary part, and is characterized in that the main shaft sequentially penetrates through the main positioning block and the auxiliary positioning block, then is connected with the operation auxiliary part, is in sliding connection with the main positioning block and the auxiliary positioning block, and is fixed through bolts; and the main positioning block is connected with the operation auxiliary part through a spring. Through the synergistic effect of the main positioning block, the auxiliary positioning block, the main shaft, the spring and the operation auxiliary part, a detector can apply force more conveniently, the measurement difficulty is reduced, and the sizes of a W gap and an X gap can be reflected more accurately. The main positioning block abuts against the shell. And the main shaft is plugged into the test port and is in contact with a middle shaft of the high-speed circuit breaker. The operation assisting part provides a stable force application point. The spring not only drives the main positioning block and the auxiliary positioning block to reset, but also drives the main positioning block and the auxiliary positioning block to form a measurement gap consistent with the X gap in size when the X gap is measured, so that the measurement accuracy and convenience are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to high speed circuit breaker detection technical field especially is related to a high speed circuit breaker gap detection device. BACKGROUND

[0002] The main circuit of the metro electric passenger train traction system comprises a pantograph, a high speed circuit breaker, a traction inverter and a traction motor. The high speed circuit breaker (HSCB) is a key component for connecting and disconnecting the main circuit of the traction system, and can quickly disconnect the circuit and quickly extinguish the arc generated by the constant overvoltage. It also has an overcurrent protection function to ensure the normal operation of the train traction system.

[0003] Taking the UR6 type high speed circuit breaker of Swiss SAEF as an example, the high speed circuit breaker is an air naturally cooled DC high speed current limiting circuit breaker, which mainly comprises five different functional components: a main circuit, a tripping device, a closing device, auxiliary contacts and an arc extinguishing chamber, and is designed as a separate installation unit. The core tripping device and closing device are composed of precise mechanical components. Therefore, in order to ensure the good performance of the high speed circuit breaker, the professional maintenance team needs to detect the W gap and X gap of the high speed circuit breaker every year.

[0004] The detection of the W gap is used to reflect the wear condition of the moving main contact 8 and the static main contact 9. As shown in the figure, a test port is arranged at the position corresponding to the middle shaft 5 at the end of the high speed circuit breaker closing device, and a depth gauge provided by the manufacturer is used to indirectly evaluate the thickness and wear condition of the moving main contact 8 and the static main contact 9 by measuring the pushing distance of the middle shaft 5. Figure 5

[0005] The detection of the X gap is used to evaluate the state of the tripping device. The measurement process is as follows: first, when the depth gauge contacts the middle shaft 5, the distance X1 between the depth gauge and the surface of the shell of the high speed circuit breaker is recorded. Then, by pressing the depth gauge, the middle shaft 5 drives the fork 6 to contact the roller 7, and the distance X2 between the depth gauge and the surface of the shell is measured again. The size of the X gap is equal to the difference between X1 and X2, which directly reflects the distance between the fork 6 and the roller 7, thereby evaluating the state of the tripping device.

[0006] The applicant finds that the design of the depth gauge of the prior art at least has the following technical problems:

[0007] The depth gauge is a one-piece cylindrical structure with small size, which is not convenient for the detection personnel to exert force, especially in the measurement process of the W gap, which needs to be performed after the electric attraction of the circuit breaker, which conflicts with the maintenance process of the electric passenger train after power off, increases the test time and safety risk. If tested in the non-electric state, the detection personnel needs to overcome the elastic force of the reset spring 10 up to 200N, and due to the small size of the depth gauge, it is particularly difficult to exert force, which affects the accuracy of the measurement result. ​

[0008] In addition, the X-gap measurement requires high precision, and it is difficult to measure using a depth gauge. It requires two people to work together: one person presses down the depth gauge and the other person holds the vernier caliper level for measurement. The limited operating space makes it easy to produce measurement errors, affecting the accuracy of the measurement results.

[0009] Furthermore, depth gauges are usually sold as part of a tool kit, not separately, and are expensive. The other tools in the kit are not useful for vehicle repair, adding unnecessary costs.

[0010] In view of the above, this utility model is hereby proposed. Utility Model Content

[0011] The purpose of this invention is to provide a high-speed circuit breaker gap detection device to solve the technical problems existing in the technology where depth gauges are used as detection tools for W and X gaps. Due to their small, one-piece cylindrical structure, these gauges are inconvenient for operators to apply force, making measurement difficult and prone to errors, thus affecting the accuracy of the measurement results. The various technical effects of the preferred technical solution provided by this invention are detailed below.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] This utility model provides a high-speed circuit breaker gap detection device, including a main positioning block, a slave positioning block, a main shaft, and an operation auxiliary part. The main shaft passes through the main positioning block and the slave positioning block in sequence and is connected to the operation auxiliary part. The main positioning block and the slave positioning block are slidably connected to the main shaft and can be fixedly maintained in relative position with the main shaft by bolts. The main positioning block and the slave positioning block are respectively connected to the operation auxiliary part by springs.

[0014] Preferably, the main positioning block is provided with a sliding groove for the auxiliary positioning block to move back and forth.

[0015] Preferably, the main positioning block and the slave positioning block are respectively provided with positioning holes, and the main shaft is provided with connecting holes that are adapted to the positioning holes, and are connected by bolts.

[0016] Preferably, the portion of the spindle exposed between the main positioning block and the operation auxiliary part is a compression section, and the free end of the spindle exposed outside the main positioning block is a guide section. The length of the compression section is 13 mm, and the length of the guide section is 2 mm.

[0017] Preferably, X-gap identification grooves are provided on both sides of the closed end of the slide, and the width of the X-gap identification grooves is 0.4mm-1mm.

[0018] Preferably, the outer wall surface of the main positioning block is provided with markings, the markings including W gap standard numerical range markings and X gap standard numerical range markings.

[0019] Preferably, the operation auxiliary part is provided with a fixing hole, and the main shaft is provided with a connecting hole that matches the fixing hole, and the two parts are connected by bolts.

[0020] Preferably, the main positioning block is connected to the operation auxiliary part via a first spring. The operation auxiliary part has a receiving groove at one end near the main positioning block. A first boss is provided in the receiving groove. First mounting grooves are provided on both sides of the opening end of the slide. The two ends of the first spring are respectively connected to the first boss and the first mounting groove.

[0021] Preferably, the positioning block is connected to the operation assistance part via a second spring, the first boss has a second mounting groove, the positioning block has a second boss, and the two ends of the second spring are respectively connected to the second boss and the second mounting groove.

[0022] The preferred technical solution of this utility model can also produce at least the following technical effects:

[0023] This invention effectively avoids the technical problems of using depth gauges as detection tools for W and X gaps in existing technologies. Due to their small, one-piece cylindrical structure, these gauges are inconvenient for operators to apply force, making measurement difficult and prone to errors, thus affecting the accuracy of the measurement results. This invention provides a high-speed circuit breaker gap detection device, including a main positioning block, a slave positioning block, a main shaft, and an operating auxiliary part. The main shaft passes through the main and slave positioning blocks sequentially and is connected to the operating auxiliary part. The main and slave positioning blocks are slidably connected to the main shaft and are fixedly positioned relative to it by bolts. The main and slave positioning blocks are connected to the operating auxiliary part by springs. Through the synergistic effect of the main and slave positioning blocks, the main shaft, the springs, and the operating auxiliary part, this invention allows operators to apply force more easily, reducing measurement difficulty and more accurately reflecting the size of the W and X gaps. The main positioning block abuts against the casing of the high-speed circuit breaker to provide stable support. The slave positioning block forms a measurement gap with the main positioning block when measuring the X gap, improving the accuracy of the measurement results. The spindle is inserted into the test port to contact the central shaft of the high-speed circuit breaker for gap measurement. The operating aid provides a more stable point of force application for the operator, facilitating operation. Springs drive the main and secondary positioning blocks back to their initial positions. When measuring the X-gap, after the spindle contacts the central shaft, the spring force causes the main positioning block to move relative to the secondary positioning block, creating a measurement gap that matches the size of the X-gap, improving measurement accuracy and convenience. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the results of a high-speed circuit breaker gap detection device provided by this utility model;

[0026] Figure 2 This is a schematic diagram showing another perspective of the high-speed circuit breaker gap detection device provided by this utility model;

[0027] Figure 3 yes Figure 1 Side view;

[0028] Figure 4 This is a schematic diagram showing another perspective of the high-speed circuit breaker gap detection device provided by this utility model;

[0029] Figure 5 This is a schematic diagram of the internal structure of a high-speed circuit breaker.

[0030] In the picture:

[0031] 1. Main positioning block; 101. Slide groove; 102. First positioning hole; 103. X-gap identification groove; 104. W-gap standard value range mark; 105. X-gap standard value range mark; 106. First mounting groove;

[0032] 2. From the positioning block; 201, the second positioning hole; 202, the second boss;

[0033] 3. Main spindle; 301. Compression section; 302. Guide section;

[0034] 4. Operation auxiliary part; 401. Receiving groove; 402. First boss; 403. Fixing hole; 404. Second mounting groove;

[0035] 5. Central shaft; 6. Shift fork; 7. Roller; 8. Moving main contact; 9. Stationary main contact; 10. Return spring. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0037] like Figures 1-4 As shown, this utility model provides a high-speed circuit breaker gap detection device, including a main positioning block 1, a slave positioning block 2, a main shaft 3, and an operation auxiliary part 4. The main shaft 3 passes through the main positioning block 1 and the slave positioning block 2 in sequence and is connected to the operation auxiliary part 4. The main positioning block 1 and the slave positioning block 2 are slidably connected to the main shaft 3 and are respectively fixedly maintained in relative position with the main shaft 3 by bolts. The main positioning block 1 and the slave positioning block 2 are respectively connected to the operation auxiliary part 4 by springs.

[0038] Through the coordinated action of the main positioning block 1, the slave positioning block 2, the main shaft 3, the spring, and the operating auxiliary part 4, the testing personnel can more easily apply force, reducing the measurement difficulty and more accurately reflecting the size of the W gap and X gap. Specifically, the main positioning block 1 is used to abut against the housing of the high-speed circuit breaker to provide stable support. The slave positioning block 2 is used to form a measuring gap with the main positioning block 1 when measuring the X gap, improving the accuracy of the measurement results. The main shaft 3 is used to insert into the test port and contact the central shaft 5 of the high-speed circuit breaker for gap measurement. The operating auxiliary part 4 provides a more stable point of force application for the testing personnel, facilitating operation. The spring is used to drive the main positioning block 1 and the slave positioning block 2 back to their initial positions, and when the main shaft 3 contacts the central shaft 5 during X gap measurement, the spring force will drive the main positioning block 1 to move relative to the slave positioning block 2, forming a measuring gap consistent with the size of the X gap, improving measurement accuracy and convenience.

[0039] Furthermore, the main positioning block 1, the secondary positioning block 2, and the operation auxiliary part 4 adopt a cuboid structure with rounded corners. This design, compared to existing small, one-piece, columnar depth gauges, increases the size of the device, making it easier for inspectors to grip and apply force.

[0040] As an optional implementation, such as Figure 1 As shown, the main positioning block 1 has a sliding groove 101 for reciprocating movement from the positioning block 2.

[0041] The slide 101 provides a stable moving track for the positioning block 2.

[0042] This setup facilitates observation of the measurement gap formed between the positioning block 2 and the main positioning block 1, specifically the gap between the positioning block 2 and the closed end of the slide groove 101.

[0043] As an optional implementation, such as Figure 1 As shown, the main positioning block 1 and the slave positioning block 2 are respectively provided with positioning holes, and the spindle 3 is provided with connecting holes that are adapted to the positioning holes, and is connected by bolts.

[0044] Furthermore, the main positioning block 1 has a first positioning hole 102, and the positioning block 2 has a second positioning hole 201. The spindle 3 has multiple connecting holes that are adapted to the first positioning hole 102 and the second positioning hole 201. The first positioning hole 102 is connected to the connecting hole of the spindle 3 by a first bolt, and the second positioning hole 201 is connected to the connecting hole of the spindle 3 by a second bolt.

[0045] As an optional implementation, such as Figure 3 As shown, the portion of the spindle 3 exposed between the end faces of the main positioning block 1 and the operation auxiliary part 4 is the compression section 301, and the free end of the spindle 3 exposed outside the main positioning block 1 is the guide section 302. The length of the compression section 301 is 13 mm, and the length of the guide section 302 is 2 mm.

[0046] The guide section 302 is 2mm long and is used to insert into the test port. The compression section 301 is 13mm long, and the guide section 302 and the compression section together are 15mm long, which is consistent with the length of the depth gauge.

[0047] As an optional implementation, such as Figure 2 As shown, X-gap identification grooves 103 are provided on both sides of the closed end of the slide groove 101, and the width of the X-gap identification grooves 103 is 0.4mm-1mm.

[0048] Furthermore, the X-gap identification groove 103 is located on the side away from the first positioning hole 102, and the straight-line distance between it and the closed end of the slide groove 101 is 0.4m. It is used to provide the inspection personnel with an intuitive visual reference when it is not necessary to record the X-gap value, so as to determine whether the gap between the main positioning block 1 and the slave positioning block 2 is between 0.4mm and 1mm, which is convenient for the inspection personnel to observe and compare.

[0049] When measuring the X-gap, the gap between the main positioning block 1 and the slave positioning block 2 can be directly compared with the X-gap identification groove 103 to intuitively determine whether the X-gap meets the standard. If the gap between the main positioning block 1 and the slave positioning block 2 is within the range of the X-gap identification groove 103, the X-gap is determined to meet the standard; otherwise, the X-gap is determined not to meet the standard.

[0050] As an optional implementation, such as Figure 2 As shown, the outer wall of the main positioning block 1 is marked with markings, including W gap standard value range marking 104 and X gap standard value range marking 105.

[0051] Furthermore, the marking and the X-gap identification groove 103 are set on the same side of the main positioning block 1.

[0052] This setup allows inspectors to quickly determine whether the W and X gaps meet the standards, improving the convenience of the inspection.

[0053] As an optional implementation, the operation assistance part 4 is provided with a fixing hole 403, and the main shaft 3 is provided with a connecting hole that matches the fixing hole 403, and is connected by bolts.

[0054] As an optional implementation, such as Figure 1 , Figure 4 As shown, the main positioning block 1 is connected to the operation auxiliary part 4 via a first spring. The operation auxiliary part 4 has a receiving groove 401 at one end near the main positioning block 1. A first boss 402 is provided in the receiving groove 401. A first mounting groove 106 is provided on both sides of the opening end of the slide groove 101. The two ends of the first spring are respectively connected to the first boss 402 and the first mounting groove 106.

[0055] Furthermore, the first mounting groove 106 is an annular intermittent groove.

[0056] One end of the first spring is sleeved on the first boss 402, and the other end is embedded in the first mounting groove 106. The arrangement of the first boss 402 and the first mounting groove 106 not only improves the connection stability between the first spring and the operation auxiliary part 4 and the main positioning block 1, but also provides guidance for the extension and retraction of the first spring.

[0057] It should be noted that when the operation assistance part 4 abuts against the end face of the main positioning block 1, the first boss 402 and the first mounting groove 106 will not interfere.

[0058] As an optional implementation, such as Figure 1 , Figure 4 As shown, the positioning block 2 is connected to the operation auxiliary part 4 via the second spring. The first boss 402 is provided with a second mounting groove 403. The positioning block 2 is provided with a second boss 202. The two ends of the second spring are respectively connected to the second boss 202 and the second mounting groove 403.

[0059] One end of the second spring is sleeved on the second boss 202, and the other end is embedded in the second mounting groove 403. The setting of the second boss 202 and the second mounting groove 403 not only improves the connection stability between the second spring and the operation auxiliary part 4 and the positioning block 2, but also provides guidance for the extension and retraction of the second spring.

[0060] The first spring ring is located outside the second spring, and the extension and retraction of the two do not interfere with each other.

[0061] As an optional implementation, the main positioning block 1, the slave positioning block 2, the main shaft 3, and the operation auxiliary part 4 are made of aluminum alloy that has undergone an oxidation process. This not only ensures that the overall weight of the device is appropriate, making it easy to carry and operate, but also that the device has a beautiful, stylish, and elegant appearance, is sturdy and durable, and has a long service life.

[0062] The working principle of this utility model for measuring the W gap is as follows: First, the guide section 302 of the main shaft 3 is inserted into the test port, and the main positioning block 1 is tightly abutted against the outer casing of the high-speed circuit breaker. Then, the inspector applies appropriate force to the operating auxiliary part 4 to overcome the elastic force of the return spring 10 inside the high-speed circuit breaker, pressing the main shaft 3 into place. Finally, the presence of a gap between the operating auxiliary part 4 and the main positioning block 1 is observed to determine whether the W gap meets the standard. If the gap between the operating auxiliary part 4 and the main positioning block 1 is less than or equal to the preset standard value, the W gap is determined to not meet the standard. Conversely, if the gap is greater than or equal to the preset standard value, the W gap is determined to meet the standard.

[0063] This invention enables the measurement of the W-gap of a high-speed circuit breaker in a train without power, providing a feasibility for optimizing the operation process.

[0064] The working principle of this utility model for measuring X-gap is as follows: First, a first measurement is performed by inserting the main shaft 3 into the test port and ensuring that the main positioning block 1 is in close contact with the housing of the high-speed circuit breaker. Then, the operator applies appropriate force to the operating auxiliary part 4, driving the main shaft 3 to drive the central shaft 5 to push the shift fork 6 into contact with the roller 7. Next, the second bolt is rotated to fix the relative position of the positioning block 2 and the main shaft 3; at this time, the second spring is in a compressed state.

[0065] A second measurement is performed by inserting the main shaft 3 back into the test port. Then, the operator applies appropriate force to the operating auxiliary part 4, causing the main shaft 3 to contact the central shaft 5. At this point, the first spring is compressed. The spring force acts on the main positioning block 1, causing it to slide relative to the main shaft 3, moving away from the slave positioning block 2 and creating a gap. This gap size matches the X-gap size of the high-speed circuit breaker. Next, the first bolt is rotated to fix the relative position of the main positioning block 1 and the main shaft 3. Finally, the device is removed, and a vernier caliper is used to measure the gap between the main positioning block 1 and the slave positioning block 2. This value is the X-gap size. If the X-gap size is within the preset standard range, the X-gap is deemed to meet the standard. Otherwise, the X-gap is deemed not to meet the standard.

[0066] This invention effectively reduces the difficulty of measuring the X-gap of high-speed circuit breakers, avoids human measurement errors, and improves measurement accuracy. Furthermore, it allows a measurement task that previously required two people to be completed independently by one person, reducing operating costs and improving the stability and reliability of the measurement work.

[0067] It should be noted that during the measurement process, the inspector relies on different force feedbacks to accurately determine the current operating state. This is a professional skill of the inspector, and similarly, when using depth gauges for measurement in existing technologies, the inspector also relies on force feedback to determine the operating state. Specifically, when measuring the W gap, when the spindle 3 overcomes the spring force of the reset spring 10 inside the high-speed circuit breaker and is pressed into place, the inspector can feel a significant resistance overcoming process through the operation auxiliary part 4. When measuring the X gap, when the spindle 3 drives the central shaft 5 to push the shift fork 6 into contact with the roller 7, due to the interaction between the shift fork 6 and the roller 7, the inspector can feel additional resistance through the operation auxiliary part 4; while when the spindle 3 only contacts the central shaft 5 but does not drive the shift fork 6 into contact with the roller 7, a relatively small reaction force can be felt. Through different force feedbacks, the inspector can accurately determine the current operating state, ensuring the accuracy and reliability of the measurement.

[0068] It is understood that the same or similar parts in the above embodiments can be referred to each other, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0069] In the description of this utility model, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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 this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "a particular example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A high-speed circuit breaker gap detection device, characterized in that, It includes a main positioning block, a slave positioning block, a main spindle, and an operation auxiliary part. The main spindle passes through the main positioning block and the slave positioning block in sequence and is connected to the operation auxiliary part. The main positioning block and the slave positioning block are slidably connected to the main spindle and can be fixedly maintained in relative position with the main spindle by bolts. The main positioning block and the slave positioning block are respectively connected to the operation auxiliary part by springs.

2. The high-speed circuit breaker gap detection device according to claim 1, characterized in that, The main positioning block is provided with a sliding groove for the auxiliary positioning block to move back and forth.

3. The high-speed circuit breaker gap detection device according to claim 1, characterized in that, The main positioning block and the slave positioning block are respectively provided with positioning holes, and the main shaft is provided with connecting holes that are adapted to the positioning holes, and are connected by bolts.

4. The high-speed circuit breaker gap detection device according to claim 1, characterized in that, The portion of the spindle exposed between the main positioning block and the operation auxiliary part is a compression section, and the free end of the spindle exposed outside the main positioning block is a guide section. The length of the compression section is 13 mm, and the length of the guide section is 2 mm.

5. A high-speed circuit breaker gap detection device according to claim 2, characterized in that, The closed end of the slide is provided with X-gap identification grooves on both sides, and the width of the X-gap identification grooves is 0.4mm-1mm.

6. The high-speed circuit breaker gap detection device according to claim 1, characterized in that, The outer wall of the main positioning block is marked with markings, including markings for the standard numerical range of the W gap and the standard numerical range of the X gap.

7. The high-speed circuit breaker gap detection device according to claim 1, characterized in that, The operation auxiliary part is provided with a fixing hole, and the main shaft is provided with a connecting hole that matches the fixing hole, and they are connected by bolts.

8. The high-speed circuit breaker gap detection device according to claim 2, characterized in that, The main positioning block is connected to the operation auxiliary part via a first spring. The operation auxiliary part has a receiving groove at one end near the main positioning block. A first boss is provided in the receiving groove. First mounting grooves are provided on both sides of the opening end of the slide. The two ends of the first spring are respectively connected to the first boss and the first mounting groove.

9. A high-speed circuit breaker gap detection device according to claim 8, characterized in that, The positioning block is connected to the operation auxiliary part via a second spring. A second mounting groove is provided on the first boss. A second boss is provided on the positioning block. The two ends of the second spring are respectively connected to the second boss and the second mounting groove.

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