Spraying device

Abstract

The utility model provides a spraying device which comprises a flow guide cover which comprises an inner cover body and an outer cover body, the outer cover body covers the outer side of the inner cover body, a gap is formed between the inner cover body and the outer cover body, an annular airflow channel is formed between the inner cover body and the outer cover body through the gap, an air inlet is formed in one end of the outer cover body and communicated with the airflow channel, and an air outlet is formed in the other end of the outer cover body. Two ends of the airflow channel are parallel to each other; the diameter of the inner cover is gradually increased along the airflow direction; the water supply pipe is arranged at the end, away from the air inlet, of the airflow channel, the water supply pipe is annularly arranged, a water inlet is formed in the water supply pipe, and a plurality of nozzles are annularly arranged on the side wall of the water supply pipe at intervals. By means of the technical scheme, the problem that in the prior art, a spraying device cannot effectively conduct dust falling on the cutting position of the roller and the coal wall can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mining, in particular to a spray device. Background Art

[0002] A shearer is a key component of a fully mechanized mining system. During operation, its drum cuts through the coal wall to extract coal. However, as the shearer operates, it emits a large amount of dust. Currently, the main method for reducing dust is to install a spray device on the shearer using water mist.

[0003] In the prior art, the spray device mainly includes a nozzle and a fan. The nozzle is arranged on the air outlet side of the fan. The fan drives the water mist sprayed from the nozzle to spray outward by blowing air, thereby increasing the diffusion radius of the water mist, increasing the area of the mist floating in the air, and increasing the contact area between the water mist and the dust, thereby enhancing the effect of atomization and dust reduction. However, when the fan blows the water mist to diffuse, the water mist is blown by the wind, and the diffusion direction is poor. The water mist will be dispersed over a large area on the working surface. During the operation of the coal mining machine drum, dust mainly escapes from the surrounding area where the coal mining machine drum cooperates with the coal wall. In the prior art solution, the water mist has a large diffusion range and cannot effectively reduce dust in the cutting area where the drum cooperates with the coal wall. Utility Model Content

[0004] The utility model provides a spray device to solve the problem that the spray device in the prior art cannot effectively reduce dust at the cutting position between the drum and the coal wall.

[0005] The utility model provides a spray device, which comprises: a flow guide cover, comprising an inner cover and an outer cover, the outer cover being arranged on the outside of the inner cover, a gap being provided between the inner cover and the outer cover, an annular air flow channel being formed between the inner cover and the outer cover through the gap, an air inlet being provided at one end of the outer cover, the air inlet being communicated with the air flow channel, the two ends of the air flow channel being parallel to each other, and the diameter of the inner cover gradually increasing along the air flow direction; a water supply pipe being provided at one end of the air flow channel away from the air inlet, the water supply pipe being arranged in an annular manner, the water inlet being provided on the water supply pipe, and a plurality of nozzles being arranged at annular intervals on the side wall of the water supply pipe.

[0006] Furthermore, the diameter of the outer cover gradually increases along the airflow direction, and the side walls of the inner cover and the outer cover are arranged parallel to each other.

[0007] Furthermore, an air intake pipe is provided on the outer cover, the air intake pipe is connected to the air inlet, the air intake pipe is used to connect the air inlet and the air supply equipment, and a guide member is provided in the air intake pipe to guide the air flow entering the air inlet.

[0008] Furthermore, the guide member includes a guide column, which is fixedly arranged in the air intake pipe. There is a gap between the guide column and the side wall of the air intake pipe. The guide column has a tapered section, and the diameter of the tapered section gradually increases along the airflow direction.

[0009] Furthermore, the guide column is fixedly connected to the top of the inner cover, and a plurality of fixing plates are arranged on the side wall of the guide column at annular intervals. The fixing plates extend along the extension direction of the air intake pipe, and one side edge of the fixing plate that is relatively set along the width is fixedly connected to the side wall of the guide column, and the other side edge of the fixing plate that is relatively set along the width is fixedly connected to the inner wall of the air intake pipe.

[0010] Furthermore, the spray device also includes a connecting assembly, which is used to connect the spray device with the coal mining machine rocker arm. The connecting assembly includes a connecting seat and a connecting rod. The connecting seat is connected to the coal mining machine rocker arm. The connecting rod has a first extension section and a second extension section that are connected to each other. The end of the first extension section away from the second extension section is connected to the connecting seat, and the end of the second extension section away from the first extension section is connected to the air guide cover. The first extension section and the second extension section are perpendicular to each other, the second extension section is arranged parallel to the coal mining machine rocker arm, and the air flow channel is arranged toward the coal wall.

[0011] Furthermore, the second extension section has a first connecting part and a second connecting part that are hinged to each other, the end of the first connecting part away from the second connecting part is connected to the first extension section, and the end of the second connecting part away from the first connecting part is connected to the air deflector, and a driving member is also provided on the connecting rod, which is drivably connected to the second connecting part and is used to drive the second connecting part to rotate relative to the first connecting part.

[0012] Furthermore, the driving member includes a telescopic rod, one end of the telescopic rod is hinged to the first connecting portion, and the other end of the telescopic rod is hinged to the second connecting portion.

[0013] Furthermore, the connecting seat includes a connecting plate, a first gear and a second gear. The first gear and the second gear are rotatably arranged on the end face of the connecting plate. The first gear and the second gear are engaged with each other. The end of the first extension section away from the second extension section is fixedly connected to the end face of the first gear, and a wrench structure is provided on the second gear.

[0014] Furthermore, a plurality of first connecting holes are arranged at annular intervals on the connecting plate, and a plurality of second connecting holes are arranged at annular intervals on the first gear. The plurality of first connecting holes and the plurality of second connecting holes are arranged in a one-to-one correspondence, and the first connecting holes and the second connecting holes are used to pass fasteners to limit the rotation of the first gear relative to the connecting plate.

[0015] By applying the technical solution of the present invention, the spray device is set to include two parts, namely a guide cover and a water supply pipe. After the guide cover takes in air through the air inlet, the air flow can be blown out along the air flow channel formed by the gap between the inner cover and the outer cover. The diameter of the inner cover increases along the air flow direction. The gas will form a trumpet-shaped jet airflow when passing through the air flow channel. The annularly arranged water supply pipe can spray water from the nozzle after water supply. The sprayed water mist can increase the diffusion range under the drive of the jet airflow to form a water mist cover. The spray device can be set on the rocker arm of the coal mining machine so that the water mist cover covers the drum of the coal mining machine. The dust generated by the drum when cutting coal is covered by the water mist cover, so that the dust cannot break through the water mist cover and disperse outward, and then the drum can be concentrated for spray dust reduction. The water mist is mixed with the wind pressure for directionally blowing, which improves the power of the water mist and expands the moving speed of the water mist, thereby improving the dust removal efficiency of the spray device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of this application are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 Shows a schematic structural diagram of the spray device provided by the utility model;

[0018] Figure 2 A schematic structural diagram of the air deflector provided by the present invention from one viewing angle is shown;

[0019] Figure 3 Shows a schematic structural diagram of the airflow channel provided by the utility model;

[0020] Figure 4 A structural schematic diagram of the air deflector provided by the present invention from another perspective is shown;

[0021] Figure 5 Shown Figure 1 A partial enlarged view of point A in the middle.

[0022] The above drawings include the following reference numerals:

[0023] 100. fairing;

[0024] 110, inner cover; 120, outer cover; 121, air inlet; 130, air inlet pipe; 140, guide column; 150, fixing plate;

[0025] 200, water supply pipe;

[0026] 210, nozzle; 220, water injection pipe;

[0027] 300, connecting seat;

[0028] 310, connecting plate; 320, first gear; 330, second gear; 331, wrench structure;

[0029] 400, connecting rod;

[0030] 410, first extension section; 420, second extension section; 421, first connecting portion; 422, second connecting portion; 423, telescopic rod. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] like Figures 1 to 4 As shown, an embodiment of the present invention provides a spray device, which includes a flow deflector 100 and a water supply pipe 200. The flow deflector 100 includes an inner cover 110 and an outer cover 120. The outer cover 120 is arranged on the outside of the inner cover 110. There is a gap between the inner cover 110 and the outer cover 120. The gap forms an annular air flow channel between the inner cover 110 and the outer cover 120. An air inlet 121 is provided at one end of the outer cover 120. The air inlet 121 is connected to the air flow channel. The two ends of the air flow channel are parallel to each other. The diameter of the inner cover 110 gradually increases along the air flow direction. The water supply pipe 200 is provided at the end of the air flow channel away from the air inlet 121. The water supply pipe 200 is arranged in an annular manner and is provided with a water inlet. A plurality of nozzles 210 are provided at annular intervals on the side wall of the water supply pipe 200.

[0033] By applying the technical solution of the present invention, the spray device is set to include two parts, namely, a guide cover 100 and a water supply pipe 200. After the guide cover 100 takes in air through the air inlet 121, the air flow can be blown out along the air flow channel formed by the gap between the inner cover 110 and the outer cover 120. The diameter of the inner cover 110 increases along the air flow direction. When the gas passes through the air flow channel, a trumpet-shaped jet air flow is formed. After the annular water supply pipe 200 is supplied with water, the water flow can be sprayed out from the nozzle 210. The sprayed water mist can increase the diffusion range under the drive of the jet air flow to form a water mist cover. The spray device can be set on the rocker arm of the coal mining machine so that the water mist cover covers the drum of the coal mining machine. The dust generated by the drum when cutting coal is covered by the water mist cover, so that the dust cannot break through the water mist cover and disperse outward, and then the drum can be concentrated for spray dust reduction. The water mist is mixed with the wind pressure for directionally blowing, which increases the power of the water mist and expands the moving speed of the water mist, thereby improving the dust removal efficiency of the spray device.

[0034] Furthermore, the diameter of the outer cover 120 gradually increases along the direction of airflow, and the sidewalls of the inner cover 110 and the outer cover 120 are arranged parallel to each other. This arrangement, in which the diameters of both the inner cover 110 and the outer cover 120 gradually increase along the direction of airflow and are arranged parallel to each other, improves the flow of gas within the airflow channel, reduces gas pressure drop, and allows the water mist generated by the nozzle 210 to be directed by the high-pressure air to form a conical, high-speed flowing water mist shroud, which surrounds the drum of the coal mining machine and prevents dust generated therefrom from escaping.

[0035] In a specific embodiment of the present application, an air inlet pipe 130 is provided on the outer cover 120. The air inlet pipe 130 is connected to the air inlet 121 and is used to connect the air inlet 121 with the air supply equipment. A flow guide is provided within the air inlet pipe 130 to guide the airflow entering the air inlet 121. Through this configuration, the flow guide can guide the gas entering the air flow channel, reducing the flow resistance caused by the gas directly impacting the inner cover 110 when the gas directly enters the gap between the inner cover 110 and the outer cover 120, thereby ensuring the flow rate and flow effect of the fluid.

[0036] like Figure 2 and Figure 3 As shown, the flow guide includes a flow guide post 140 fixedly mounted within the intake pipe 130. There is a gap between flow guide post 140 and the sidewall of the intake pipe 130. The flow guide post 140 has a tapered section whose diameter gradually increases along the direction of airflow. This arrangement allows gas entering the intake pipe 130 to be dispersed circumferentially around flow guide post 140 under the guidance of the tapered section and enter the airflow channel, thereby guiding the gas and reducing flow resistance.

[0037] Specifically, the guide column 140 may also be provided with a straight section, which is sequentially connected to the tapered section to increase the overall length of the guide column 140 so as to facilitate adjustment of the guiding effect of the guide member on the gas.

[0038] Furthermore, the guide post 140 is fixedly connected to the top of the inner cover 110. A plurality of fixing plates 150 are annularly spaced apart on the sidewalls of the straight or tapered sections of the guide post 140. The fixing plates 150 extend along the extension direction of the intake duct 130. One side of the fixing plates 150, which is positioned opposite to the other, is fixedly connected to the sidewall of the guide post 140. The other side of the fixing plates 150, which is positioned opposite to the other, is fixedly connected to the inner wall of the intake duct 130. This arrangement allows airflow to pass through the spaces between the plurality of annularly spaced fixing plates 150. While the guide post 140 and the intake duct 130 are connected, the connection structure does not affect the flow of air.

[0039] Specifically, a connecting plate is provided at one end of the inner cover 110 close to the air inlet, and the connecting plate is fixedly connected to the guide column 140 , so that the outer cover 120 and the inner cover 110 can be connected together.

[0040] In other embodiments of the present application, the inner cover 110 may be tapered as a whole, with the apex of the cone located within the air inlet pipe 130 , so that the fluid entering the air flow channel may be guided by the inner cover 110 .

[0041] In the present application, a water injection pipe 220 is provided on the water supply pipe 200 , and the water injection pipe 220 passes through the outer cover 120 to be connected to the water supply equipment.

[0042] Furthermore, the spray device also includes a connecting assembly, which is used to connect the spray device to the rocker arm of the coal mining machine. The connecting assembly includes a connecting seat 300 and a connecting rod 400. The connecting seat 300 is connected to the rocker arm of the coal mining machine. The connecting rod 400 has a first extension section 410 and a second extension section 420 that are connected to each other. The end of the first extension section 410 away from the second extension section 420 is connected to the connecting seat 300, and the end of the second extension section 420 away from the first extension section 410 is connected to the air deflector 100. The first extension section 410 and the second extension section 420 are perpendicular to each other. The second extension section 420 is arranged parallel to the rocker arm of the coal mining machine, and the air flow channel is arranged toward the coal wall. Through the above arrangement, the air deflector 100 can be installed on the rocker arm of the coal mining machine through the connecting seat 300 and the connecting rod 400, which facilitates the installation and use of the entire spray device, so that the air deflector 100 is arranged corresponding to the coal wall, and the dust at the drum is targetedly reduced.

[0043] like Figure 1As shown, the second extension section 420 has a first connection portion 421 and a second connection portion 422 that are hinged to each other. The end of the first connection portion 421 away from the second connection portion 422 is connected to the first extension section 410, and the end of the second connection portion 422 away from the first connection portion 421 is connected to the air deflector 100. The connecting rod 400 is also provided with a driving member that is drivingly connected to the second connection portion 422 and is used to drive the second connection portion 422 to rotate relative to the first connection portion 421. Through the above arrangement, the driving member can rotate the second connection portion 422 relative to the first connection portion 421, thereby adjusting the opening angle of the air deflector 100 and the distance from the area where dust reduction is required, and further adjusting the concentrated direction of the spray, so that the water mist can be sprayed to the area where dust reduction is required.

[0044] In one embodiment of the present application, the driving member includes a telescopic rod 423, one end of which can be hinged to the first connecting portion 421 via an ear seat, and the other end of the telescopic rod 423 can be hinged to the second connecting portion 422 via an ear seat. In this arrangement, by adjusting the distance between the two telescopic ends of the telescopic rod 423, the second connecting portion 422 can be driven to rotate relative to the first connecting portion 421, thereby facilitating adjustment of the spray direction of the water mist.

[0045] Specifically, an end of the second connection portion 422 away from the first connection portion may be provided with a mounting member for fixing the air duct 100 . The mounting member has a sleeve, one end of the sleeve is connected to the air supply device, and the other end is connected to the air inlet pipe 130 .

[0046] Furthermore, the air inlet pipe 130 may be connected to the sleeve via a flange connection.

[0047] Reference Figure 1 and Figure 5 As shown, the connecting base 300 includes a connecting plate 310, a first gear 320, and a second gear 330. The first gear 320 and the second gear 330 are rotatably disposed on the end surface of the connecting plate 310. The first gear 320 and the second gear 330 mesh with each other. The end of the first extension section 410, which is away from the second extension section 420, is fixedly connected to the end surface of the first gear 320. The second gear 330 is provided with a wrench structure 331. Through the above arrangement, the connecting plate 310 is used to be fixedly connected to the rocker arm of the coal mining machine to achieve the installation of the integrated spray device. After the spray device is installed, the wrench structure 331 can be turned to drive the first gear 320 to rotate via the second gear 330, causing the connecting rod 400 to rotate about the first extension section 410 as the rotation axis, thereby adjusting the coverage range of the deflector 100. In conjunction with the driving member, the deflector 100 can be finely adjusted in terms of the opening angle and the distance from the dust reduction area, so that the water mist can be sprayed more accurately to the area where dust reduction is required.

[0048] Specifically, a plurality of first connection holes are provided at an annular interval on the connecting plate 310, and a plurality of second connection holes are provided at an annular interval on the first gear 320. The plurality of first connection holes correspond to the plurality of second connection holes in a one-to-one manner. The first connection holes and the second connection holes are used to pass fasteners through to restrict the rotation of the first gear 320 relative to the connecting plate 310. With this arrangement, after the angle of the air scoop 100 is adjusted, fasteners can be passed through the first connection holes and the second connection holes to restrict the rotation of the first gear 320 and secure the air scoop 100.

[0049] In the present application, at least two first connection holes and at least two second connection holes are provided to facilitate fixing the air deflector 100 at different angles. The fasteners may be plugs or bolts.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0051] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0052] In the description of the present invention, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0054] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this utility model.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A spray device, characterized in that: The spray device comprises: A deflector (100) comprises an inner cover (110) and an outer cover (120), wherein the outer cover (120) is arranged outside the inner cover (110), a gap is provided between the inner cover (110) and the outer cover (120), an annular airflow channel is formed between the inner cover (110) and the outer cover (120) through the gap, an air inlet (121) is provided at one end of the outer cover (120), the air inlet (121) is communicated with the airflow channel, both ends of the airflow channel are parallel to each other, and the diameter of the inner cover (110) gradually increases along the airflow direction; A water supply pipe (200) is arranged at one end of the air flow channel away from the air inlet (121), the water supply pipe (200) is arranged in an annular shape, a water inlet is provided on the water supply pipe (200), and a plurality of nozzles (210) are arranged at intervals on the side wall of the water supply pipe (200).

2. The spray device according to claim 1, characterized in that The diameter of the outer cover (120) gradually increases along the airflow direction, and the side walls of the inner cover (110) and the outer cover (120) are arranged parallel to each other.

3. The spray device according to claim 1, characterized in that An air intake pipe (130) is provided on the outer cover (120), the air intake pipe (130) is in communication with the air inlet (121), the air intake pipe (130) is used to connect the air inlet (121) with an air supply device, and a flow guide is provided in the air intake pipe (130) to guide the air flow entering the air inlet (121).

4. The spray device according to claim 3, characterized in that The guide member comprises a guide column (140), the guide column (140) being fixedly arranged in the air intake pipe (130), a gap being provided between the guide column (140) and a side wall of the air intake pipe (130), and the guide column (140) having a tapered section, the diameter of which gradually increases along the airflow direction.

5. The spray device according to claim 4, characterized in that The guide column (140) is fixedly connected to the top of the inner cover (110), and a plurality of fixing plates (150) are arranged on the side wall of the guide column (140) at annular intervals. The fixing plates (150) extend along the extension direction of the air intake pipe (130), and the fixing plates (150) are fixedly connected to the side wall of the guide column (140) along one side edge that is arranged opposite to each other in width, and the fixing plates (150) are fixedly connected to the inner wall of the air intake pipe (130) along the other side edge that is arranged opposite to each other in width.

6. The spray device according to claim 1, characterized in that The spray device also includes a connecting assembly, which is used to connect the spray device and the coal mining machine rocker arm. The connecting assembly includes a connecting seat (300) and a connecting rod (400). The connecting seat (300) is connected to the coal mining machine rocker arm. The connecting rod (400) has a first extension section (410) and a second extension section (420) that are connected to each other. The end of the first extension section (410) away from the second extension section (420) is connected to the connecting seat (300), and the end of the second extension section (420) away from the first extension section (410) is connected to the air guide cover (100). The first extension section (410) and the second extension section (420) are perpendicular to each other. The second extension section (420) is arranged parallel to the coal mining machine rocker arm, and the air flow channel is arranged toward the coal wall.

7. The spray device according to claim 6, characterized in that The second extension section (420) comprises a first connection portion (421) and a second connection portion (422) which are hinged to each other, wherein one end of the first connection portion (421) away from the second connection portion (422) is connected to the first extension section (410), and one end of the second connection portion (422) away from the first connection portion (421) is connected to the air deflector (100), and a driving member is further provided on the connecting rod (400), wherein the driving member is drivingly connected to the second connection portion (422) and is used for driving the second connection portion (422) to rotate relative to the first connection portion (421).

8. The spray device according to claim 7, characterized in that The driving member comprises a telescopic rod (423), one end of the telescopic rod (423) is hinged to the first connecting portion (421), and the other end of the telescopic rod (423) is hinged to the second connecting portion (422).

9. The spray device according to claim 6, characterized in that The connecting seat (300) includes a connecting plate (310), a first gear (320) and a second gear (330). The first gear (320) and the second gear (330) are rotatably arranged on the end surface of the connecting plate (310). The first gear (320) and the second gear (330) are engaged with each other. An end of the first extension section (410) away from the second extension section (420) is fixedly connected to the end surface of the first gear (320). A wrench structure (331) is provided on the second gear (330).

10. The spray device according to claim 9, characterized in that A plurality of first connection holes are provided at annular intervals on the connection plate (310), and a plurality of second connection holes are provided at annular intervals on the first gear (320). The plurality of first connection holes and the plurality of second connection holes are provided in a one-to-one correspondence, and the first connection holes and the second connection holes are used to pass fasteners to limit the rotation of the first gear (320) relative to the connection plate (310).

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