Connecting structure and loader

Abstract

The utility model belongs to the technical field of loaders, and discloses a connecting structure and a loader. The connecting structure is used for connecting a front frame and a rear frame and comprises a hinge body, a pressing piece, a first fixing piece and a locking pin, the rear frame is provided with a connecting hole, a shaft sleeve is arranged in the connecting hole, one end of the hinge body can rotate relative to the shaft sleeve, the hinge body is connected to the pressing piece through the first fixing piece, and a first pin hole is formed in a connecting shaft; the connecting arm is provided with a guide hole, the pressing piece is provided with a second pin hole, the locking pin is inserted into the first pin hole and the second pin hole, and the pressing shaft of the pressing piece is connected into the hinge body. According to the connecting structure, the connecting shaft and the pressing piece are connected through the locking pin and the first fixing piece, the connecting stability is ensured, and the use safety is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of loaders, in particular to a connection structure and a loader. Background Art

[0002] A loader is a kind of earthwork construction machinery widely used in construction projects such as highways, railways, buildings, hydropower, ports, mines, etc. It is mainly used for shoveling bulk materials such as soil, sand, gravel, lime, coal, etc., and can also perform light shoveling operations on ores, hard soils, etc. The front frame and the rear frame of the loader are connected by a hinge body. The hinge body is connected to the front frame through a pin shaft, and the hinge body is connected to the rear frame through bolts and pressing members. Due to the harsh working conditions at the construction site of the loader, it often operates in a high-dust and muddy environment, and the vibration is very large during work. When the working site is uneven, the vibration of the whole machine will be more obvious, resulting in a large load on the bolts. As the working time of the loader increases, the risk of bolt loosening increases. At that time, the hinge body will be separated from the rear frame, affecting the work of the loader and the safety of personnel. Content of the Utility Model

[0003] The purpose of the utility model is to provide a connection structure and a loader to solve the problem in the prior art that the risk of bolt loosening is relatively large, which easily leads to the separation of the hinge body and the rear frame, affecting the work of the loader and the safety of personnel.

[0004] To achieve this purpose, the utility model adopts the following technical solutions:

[0005] A connection structure for connecting a front frame and a rear frame. A connection hole is provided on the rear frame. The connection structure includes:

[0006] A hinge body, one end of the hinge body is used to connect the front frame, the other end of the hinge body is arranged in the connection hole, the hinge body is provided with a first pin hole along a first direction, and the hinge body is provided with a plug hole communicating with the first pin hole along a second direction. The first direction and the second direction are arranged at an angle;

[0007] A pressing member, the pressing member includes a pressing shaft and a pressing plate. The pressing shaft is inserted into the plug hole. The pressing shaft is provided with a second pin hole coaxial with the first pin hole. The pressing plate can abut against one end of the rear frame far from the hinge body;

[0008] A first fixing member for connecting the pressing plate and the hinge body;

[0009] A locking pin is inserted through the first pin hole and the second pin hole to connect the hinge body and the pressing shaft.

[0010] As an alternative technical solution, the connecting structure further includes a bushing, the bushing is disposed in the connecting hole, the articulated body includes a connecting portion and a connecting shaft, the connecting portion is used for connecting the front frame, the connecting shaft is rotatably connected to the bushing, and the first pin hole is opened in the connecting shaft.

[0011] As an alternative technical solution, the bushing is provided with a through hole for passing through the locking pin.

[0012] As an alternative technical solution, the through hole is disposed through the bushing.

[0013] As an alternative technical solution, the connecting structure further includes a sealing ring, the sealing ring is sleeved on the outer periphery of the connecting shaft, and the sealing ring is located in the connecting hole and abuts against the bushing.

[0014] As an alternative technical solution, the connecting structure further includes a cover plate and a second fixing member, the cover plate is disposed at an end of the pressing member away from the articulated body, and the second fixing member is used for connecting the cover plate to the rear frame.

[0015] As an alternative technical solution, the connecting structure further includes a first adjusting gasket, and the first adjusting gasket is disposed between the cover plate and the pressing plate.

[0016] As an alternative technical solution, the connecting structure further includes a second adjusting gasket, and the second adjusting gasket is disposed between the pressing plate and the rear frame.

[0017] The present utility model also adopts the following technical solutions:

[0018] A wheel loader, comprising a front frame and a rear frame, further comprising the connecting structure as described above, and the connecting structure is used for connecting the front frame and the rear frame.

[0019] As an alternative technical solution, the rear frame is provided with a guiding hole for passing through the locking pin.

[0020] The beneficial effects of the present utility model:

[0021] The present utility model discloses a connection structure for connecting a front frame and a rear frame. The connection structure includes a hinge body, a pressing member, a first fixing member, and a locking pin. The rear frame is provided with a connection hole, and the hinge body is rotatably arranged in the connection hole. The first fixing member connects the pressing member to the hinge body through the pressing member. The hinge body is provided with a first pin hole, and the pressing shaft of the pressing member is provided with a second pin hole. The locking pin can enter the pin holes to perform secondary connection on the connection shaft and the pressing member. This connection structure connects the connection shaft and the pressing member through the locking pin and the first fixing member, which can ensure the connection stability of the connection shaft and the pressing member and improve the use safety.

[0022] The present utility model also discloses a loader, which includes a front frame and a rear frame, and also includes the above-mentioned connection structure. The connection structure connects the front frame and the rear frame, so that the front frame and the rear frame of the loader have better connection performance, ensure the use safety, and are convenient to disassemble and assemble, ensuring the disassembly and assembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a partial structural schematic diagram of the connection structure in the first position according to an embodiment of the present utility model;

[0024] Figure 2 is a sectional view of the connection structure in the first position according to an embodiment of the present utility model;

[0025] Figure 3 is a partial structural schematic diagram of the connection structure in the second position according to an embodiment of the present utility model;

[0026] Figure 4 is a sectional view of the connection structure in the second position according to an embodiment of the present utility model;

[0027] Figure 5 is an exploded view of the connection structure according to an embodiment of the present utility model.

[0028] In the figure:

[0029] 10. Rear frame; 11. Connecting arm; 111. Guide hole; 112. Boss; 1121. Second threaded hole;

[0030] 20. Connection structure; 21. Hinge body; 211. Connection part; 212. Connection shaft; 2121. First pin hole; 2122. Insertion hole; 2123. First threaded hole; 22. Pressing member; 221. Pressing shaft; 2211. Second pin hole; 222. Pressing plate; 23. First bolt; 24. Locking pin; 25. Sleeve; 251. Through hole; 26. Sealing ring; 27. Cover plate; 271. Second bolt hole; 28. Second bolt; 29. First adjusting gasket; 210. Second adjusting gasket. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present utility model, rather than limiting the present utility model. Additionally, it should be noted that for the convenience of description, only the parts related to the present utility model rather than all the structures are shown in the drawings.

[0032] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0034] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0035] Such as Figures 1 to 5As shown in the figure, in this embodiment, a connection structure 20 is provided for connecting the front frame and the rear frame 10. The connection structure 20 includes a hinge body 21, a first fixing member, a pressing member 22, and a locking pin 24. The rear frame 10 is provided with a connection hole. One end of the hinge body 21 is used to connect the front frame, and the other end of the hinge body 21 is rotatably arranged in the connection hole. The hinge body 21 is provided with a first pin hole 2121 along a first direction, and the hinge body 21 is provided with a plug hole 2122 along a second direction that communicates with the first pin hole 2121. The first direction and the second direction are arranged at an angle. The pressing member 22 includes a pressing shaft 221 and a pressing plate 222. The pressing shaft 221 is inserted into the plug hole 2122. The pressing shaft 221 is provided with a second pin hole 2211 that is coaxial with the first pin hole. The pressing plate 222 can abut against one end of the rear frame 10 away from the hinge body 21. The first fixing member is used to connect the pressing plate 222 and the hinge body 21. The locking pin 24 passes through the first pin hole 2121 and the second pin hole 2211 for connecting the hinge body 21 and the pressing shaft 221. Specifically, in this embodiment, the rear frame 10 includes a connecting arm 11. The connecting arm 11 is provided with a connection hole. One end of the hinge body 21 is connected to the front frame, and the other end of the hinge body 21 is connected to the connection hole. The pressing member 22 is arranged at one end of the connecting arm 11 away from the hinge body 21. The pressing plate 222 abuts against one end of the rear frame 10 away from the hinge body 21, enabling the hinge body 21 to be connected to the rear frame 10. And the hinge body 21 and the pressing plate 222 of the pressing member 22 are connected by the first fixing member. At the same time, the hinge body 21 and the pressing shaft 221 of the pressing member 22 are connected by the locking pin 24, so that there is a double connection between the hinge body 21 and the pressing member 22, ensuring the connection stability between the hinge body 21 and the pressing member 22, and further ensuring the connection stability between the front frame and the rear frame 10.

[0036] Specifically, as Figure 5 shown, the pressing plate 222 is provided with a first bolt hole, and the connecting shaft 212 is provided with a first threaded hole 2123. The first fixing member is a first bolt 23. The first bolt 23 passes through the first bolt hole and is threadedly connected to the first threaded hole 2123, thereby detachably connecting the pressing plate 222 and the connecting shaft 212. Specifically, in this embodiment, the first bolt 23 is used to connect the pressing plate 222 and the connecting shaft 212, which can not only ensure the connection stability but also facilitate disassembly and assembly, improving work efficiency.

[0037] In this embodiment, there are four first bolt holes, first threaded holes 2123, and first bolts 23. The four first bolts 23 are evenly distributed around the axis of the pressing shaft 221, which can ensure the connection stability and the uniform force of the pressing member 22. The four first bolts 23 are installed in a diagonal installation manner, which will not be elaborated here. In other embodiments, the number of the first bolt holes, first threaded holes 2123, and first bolts 23 can be specifically set according to actual needs, which will not be elaborated here.

[0038] Further, the connecting structure 20 further includes a bushing 25. The bushing 25 is disposed in the connecting hole. The articulated body 21 includes a connecting portion 211 and a connecting shaft 212. The connecting portion 211 is used to connect the front frame, the connecting shaft 212 is connected to the bushing 25, and the first pin hole 2121 is opened in the connecting shaft 212. Specifically, in this embodiment, an oil passage is provided in the bushing 25, and there is lubricating oil in the oil passage to play a lubricating role. The connecting portion 211 of the articulated body 21 is used to be articulated with the front frame. The connecting shaft 212 of the articulated body 21 is disposed in the bushing 25, and the first pin hole 2121 is opened in the connecting shaft 212.

[0039] Further, the bushing 25 is provided with a through hole 251. The through hole 251 is used for passing through the locking pin 24. Specifically, in this embodiment, the bushing 25 and the connecting hole are in interference fit. When the articulated body 21 is in the first position, the through hole 251 is coaxial with the first pin hole 2121. After the locking pin 24 passes through the through hole 251, it enters the first pin hole 2121 and the second pin hole 2211, which can ensure the installation of the locking pin 24.

[0040] Further, the through hole 251 is disposed through the bushing 25. Specifically, in this embodiment, the through hole 251 is disposed through the bushing 25. This setting can facilitate the removal of the locking pin 24 from the first pin hole 2121 and the second pin hole 2211, improving the convenience of use.

[0041] Further, the connecting structure 20 further includes a sealing ring 26. The sealing ring 26 is sleeved on the outer periphery of the connecting shaft 212, and the sealing ring 26 is located in the connecting hole and abuts against the bushing 25. Specifically, in this embodiment, the sealing ring 26 is sleeved on the outer periphery of the connecting shaft 212 and abuts against the bushing 25, which can isolate and seal the bushing 25 from the outside, prevent external impurities from entering the inside of the bushing 25, and further cause wear to the internal connecting shaft 212 and the bushing 25, improving the service life.

[0042] Further, the connecting structure 20 further includes a cover plate 27 and a second fixing member. The cover plate 27 is disposed at one end of the pressing member 22 away from the articulated body 21. The second fixing member is used to connect the cover plate 27 to the rear frame 10. Specifically, in this embodiment, please refer to Figure 1, the connecting arm 11 is provided with a boss 112, the boss 112 is provided with a counterbore, the counterbore communicates with the connecting hole, the counterbore is used to accommodate the pressing plate 222, the connecting structure 20 further includes a cover plate 27 and a second fixing member, and the second fixing member is used to detachably connect the cover plate 27 to the boss 112, and the cover plate 27 is used to block the counterbore. Specifically, in this embodiment, the counterbore of the boss 112 communicates with the connecting hole and is used to accommodate the pressing plate 222. The second fixing member connects the cover plate 27 to the boss 112, and the cover plate 27 blocks the counterbore, which can isolate the connecting hole and the counterbore from the outside, prevent external dust from entering the counterbore and the connecting hole and causing wear to the internal components, and improve the service life.

[0043] Specifically, the cover plate 27 is provided with a second bolt hole 271, the boss 112 is provided with a second threaded hole 1121, the second fixing member is a second bolt 28, and the second bolt 28 passes through the second bolt hole 271 and is threadedly connected to the second threaded hole 1121, thereby detachably connecting the cover plate 27 and the boss 112. In this embodiment, the cover plate 27 and the boss 112 on the connecting arm 11 are connected by the first bolt 23, which can ensure the connection stability and at the same time facilitate disassembly and assembly, improving work efficiency.

[0044] In this embodiment, there are six second bolt holes 271, six second threaded holes 1121 and six second bolts 28. The six second bolts 28 are evenly distributed around the axis of the pressing shaft 221, which can ensure the connection stability and force balance of the cover plate 27. The six second bolts 28 are installed in a diagonal installation method, which will not be elaborated here. In other embodiments, the number of the second bolt holes 271, the second threaded holes 1121 and the second bolts 28 can be specifically set according to actual needs, which will not be elaborated here.

[0045] Specifically, one end of the cover plate 27 close to the boss 112 is provided with a receiving groove for receiving the bolt head of the first bolt 23. Specifically, in this embodiment, this setting can help reduce the thickness of the boss 112, improve space utilization, and prevent the installation space of other components from being affected due to the excessive sizes of the boss 112 and the cover plate 27.

[0046] Further, please refer to Figure 5, the connecting structure 20 further includes a first adjusting gasket 29, and the first adjusting gasket 29 is disposed between the cover plate 27 and the pressing plate 222. Specifically, in this embodiment, the first adjusting gasket 29 is located between the cover plate 27 and the pressing plate 222, which can increase the contact area between the cover plate 27 and the pressing plate 222, make the force on the pressing plate 222 uniform, and avoid problems such as deformation of the pressing plate 222 caused by concentrated force. At the same time, the first adjusting gasket 29 can effectively fill the gap between the cover plate 27 and the pressing plate 222, improve the sealing performance between the cover plate 27 and the pressing plate 222, and prevent external impurities from entering the inside of the connecting structure 20.

[0047] Furthermore, the connecting structure 20 further includes a second adjusting gasket 210, and the second adjusting gasket 210 is disposed between the pressing plate 222 and the rear frame 10. Specifically, in this embodiment, the second adjusting gasket 210 is disposed between the pressing plate 222 and the connecting arm 11, which can increase the contact area between the pressing plate 222 and the connecting arm 11, make the force on the pressing plate 222 uniform, and avoid problems such as deformation of the pressing plate 222 caused by concentrated force. Moreover, the second adjusting gasket 210 effectively fills the gap between the connecting arm 11 and the pressing plate 222, improves the sealing performance between the connecting arm 11 and the pressing plate 222, can prevent external impurities from entering the bushing 25, resulting in wear of the bushing 25 and the connecting shaft 212, and improves the service life.

[0048] This embodiment also provides a loader, which includes a front frame and a rear frame 10, and further includes the above-mentioned connecting structure 20. The connecting structure 20 is used to connect the front frame and the rear frame 10. This loader has good connection performance between the front frame and the rear frame 10, ensures safe use, and is convenient for disassembly and assembly, ensuring the disassembly and assembly efficiency.

[0049] Furthermore, the rear frame 10 is provided with a guiding hole 111 for passing through the locking pin 24. Specifically, the articulated body 21 is rotatably arranged in the connecting hole, enabling the articulated body 21 to switch between the first position and the second position. When the articulated body 21 is in the first position, the first pin hole 2121 of the articulated body 21, the second pin hole 2211 of the pressing shaft 221, and the guiding hole 111 of the connecting arm 11 are collinear, allowing the locking pin 24 to pass through the guiding hole 111 and be inserted into the first pin hole 2121 and the second pin hole 2211, thereby connecting the connecting shaft 212 and the pressing member 22. Then, rotate the articulated body 21 so that the articulated body 21 is in the second position. At this time, the first pin hole 2121 of the connecting shaft 212, the second pin hole 2211 of the pressing shaft 221, the guiding hole 111 of the connecting arm 11, and the through hole 251 of the bushing 25 form a certain angle, which can isolate the first pin hole 2121 and the second pin hole 2211 from the outside, ensuring that the locking pin 24 can always be located in the first pin hole 2121 and the second pin hole 2211 and preventing the locking pin 24 from coming out. This setting makes the installation of the locking pin 24 convenient and efficient, and ensures the stability of the connection.

[0050] In this embodiment, as Figure 2 and Figure 4 shown, when the articulated body 21 is in the first position, the articulated body 21 is in the installation state. When the articulated body 21 is in the second position, the articulated body 21 is in the final state, and at this time, the connection structure 20 is in the state of transmitting power.

[0051] In this embodiment, when the articulated body 21 is in the first position, the extending directions of the first pin hole 2121, the second pin hole 2211, the through hole 251, and the guiding hole 111 are the first direction. When the articulated body 21 is in the second position, the extending directions of the first pin hole 2121 and the second pin hole 2211 are the second direction, and the first direction and the second direction are perpendicular. In other embodiments, the included angle between the first direction and the second direction can be specifically set according to actual use and will not be elaborated here.

[0052] In this embodiment, the diameter of the guiding hole 111 is slightly larger than the diameter of the through hole 251, which is convenient for the installation of the locking pin 24.

[0053] In this embodiment, a chamfer is provided at one end of the guiding hole 111 away from the through hole 251, which can have a certain guiding effect on the locking pin 24 and improve the installation convenience of the locking pin 24.

[0054] In this embodiment, the guiding hole 111 is penetrated through the connecting arm 11. The guiding hole 111 being penetrated through the connecting arm 11 can facilitate the removal of the locking pin 24 from the first pin hole 2121 and the second pin hole 2211 and improve the use convenience.

[0055] The installation process of the connection structure 20 of the loader will be described below. First, the bushing 25 is installed into the connection hole of the connection arm 11. During the installation process, it is necessary to make the through hole 251 of the bushing 25 coaxial with the guiding hole 111 of the connection arm 11. Then, the sealing ring 26 is sleeved on the connection shaft 212, and the connection shaft 212 is inserted into the bushing 25. Next, the pressing shaft 221 of the pressing member 22 with the first adjusting gasket 29 installed is inserted into the insertion hole 2122 of the connection shaft 212, so that the first pin hole 2121 and the second pin hole 2211 are coaxial and also coaxial with the through hole 251 and the guiding hole 111. At this time, the articulated body 21 is in the first position. Then, the locking pin 24 is installed into the first pin hole 2121 and the second pin hole 2211 after passing through the guiding hole 111 and the through hole 251. The articulated body 21 is rotated so that the articulated body 21 switches from the first position to the second position, and the pressing member 22 and the articulated body 21 are connected by the first bolt 23. Next, the second adjusting gasket 210 is installed on the outside of the pressing plate 222, and the cover plate 27 is connected to the boss 112 of the connection arm 11 by the second bolt 28 to close the counterbore of the boss 112. Finally, the sealing ring 26 is adjusted so that the sealing ring 26 can be located in the connection hole and abuts against the bushing 25. Finally, the articulated body 21 is connected to the front frame to complete the installation of the connection structure 20.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A connecting structure for connecting a front frame and a rear frame (10), wherein the rear frame (10) is provided with a connecting hole, characterized in that: The connection structure comprises: A hinged body (21), one end of the hinged body (21) is used to connect to the front frame, the other end of the hinged body (21) is arranged at the connecting hole, the hinged body (21) is provided with a first pin hole (2121) along a first direction, the hinged body (21) is provided with a plug hole (2122) connected with the first pin hole (2121) along a second direction, and the first direction and the second direction are arranged at an angle; A pressing member (22), the pressing member (22) comprising a pressing shaft (221) and a pressing plate (222), the pressing shaft (221) being inserted into the insertion hole (2122), the pressing shaft (221) being provided with a second pin hole (2211) coaxial with the first pin hole (2121), and the pressing plate (222) being capable of abutting against an end of the rear frame (10) away from the hinged body (21); A first fixing member, the first fixing member being used to connect the pressing plate (222) to the hinged body (21); A locking pin (24), wherein the locking pin (24) is inserted into the first pin hole (2121) and the second pin hole (2211) to connect the hinged body (21) and the clamping shaft (221).

2. The connection structure according to claim 1, characterized in that: The connection structure further comprises a shaft sleeve (25), wherein the shaft sleeve (25) is arranged in the connection hole, the hinged body (21) comprises a connection portion (211) and a connection shaft (212), the connection portion (211) is used to connect the front frame, the connection shaft (212) is connected to the shaft sleeve (25), and the first pin hole (2121) is opened on the connection shaft (212).

3. The connection structure according to claim 2, characterized in that: The shaft sleeve (25) is provided with a through hole (251), and the through hole (251) is used for passing the locking pin (24).

4. The connection structure according to claim 3, characterized in that: The through hole (251) is disposed through the shaft sleeve (25).

5. The connection structure according to claim 2, characterized in that: The connection structure further comprises a sealing ring (26), wherein the sealing ring (26) is sleeved on the outer periphery of the connection shaft (212), and the sealing ring (26) is located in the connection hole and abuts against the shaft sleeve (25).

6. The connection structure according to claim 1, characterized in that: The connection structure further comprises a cover plate (27) and a second fixing member, wherein the cover plate (27) is arranged at one end of the pressing member (22) away from the hinged body (21), and the second fixing member is used to connect the cover plate (27) to the rear frame (10).

7. The connection structure according to claim 6, characterized in that: The connection structure further comprises a first adjustment gasket (29), wherein the first adjustment gasket (29) is arranged between the cover plate (27) and the pressing plate (222).

8. The connection structure according to any one of claims 1 to 7, characterized in that: The connection structure also includes a second adjustment gasket (210), wherein the second adjustment gasket (210) is arranged between the pressing plate (222) and the rear frame (10).

9. A loader, comprising a front frame and a rear frame (10), characterized in that: The loader further comprises a connecting structure as claimed in any one of claims 1 to 8, wherein the connecting structure is used to connect the front frame and the rear frame (10).

10. The loader according to claim 9, characterized in that: The rear frame (10) is provided with a guide hole (111), and the guide hole (111) is used for passing the locking pin (24).

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