Composite hardened foam preparation for varicosity and preparation device thereof

Abstract

The invention discloses a composite hardened foam preparation for varicosity and a preparation device thereof, and belongs to the technical field of foam preparation devices, the composite hardened foam preparation comprises a base, a homogenizing shell is arranged at the top of the base, a stirring shell is arranged at the top of the homogenizing shell, a discharging pipe and a foaming mechanism are communicated with the side wall of the homogenizing shell, and the foaming mechanism comprises a foaming device arranged in the stirring shell; the foaming device is configured to rotate around the axis of the stirring shell and rotate at the same time, the homogenizing mechanism comprises a pore plate arranged in the homogenizing shell, a plurality of homogenizing holes with the same hole diameter are formed in the outer wall of the pore plate, the switching mechanism comprises a switching disc arranged in the homogenizing shell, and a plurality of pore plates are embedded in the switching disc. Liquid medicine is mixed through the foaming mechanism, mixed liquid is foamed at the same time, the working efficiency is improved, large bubbles are crushed into small bubbles through the homogenizing mechanism, then the bubbles are finer and more uniform, the product quality is improved, the fine density of the bubbles can be changed on the premise of not stopping through the switching mechanism, and the universality of the device is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of foam preparation device, and particularly relates to a composite hardened foam preparation for varicose veins and its preparation device. Background Technology

[0002] Varicose vein composite sclerotherapy foam is a minimally invasive treatment drug mainly used to treat varicose veins in the lower extremities. It closes the diseased veins through minimally invasive injection. Its core component is surfactants such as polidocanol or polidocanol, which promote fibrosis and closure of veins by destroying vascular endothelial cells. After the drug is mixed with air or gas, it forms fine and stable foam. The foam shape can increase the contact area between the drug and the blood vessel wall, thus improving the treatment effect.

[0003] In the clinical application of varicose vein compound sclerotherapy foam formulations, the uniformity, stability, and bubble size of the foam directly affect its therapeutic efficacy and safety. Existing preparation equipment typically treats material mixing and foaming as two separate processes, which is cumbersome and prone to introducing external air during the transfer of the mixture, resulting in low work efficiency. Existing preparation equipment produces foam with a wide range of bubble sizes and a large number of irregular bubbles, affecting the uniform distribution of the drug and thus reducing the safety and effectiveness of the treatment. In order to produce foam formulations with different densities and fineness, existing preparation equipment needs to be shut down and homogenized components with different pore sizes replaced, leading to production interruptions, reduced equipment utilization, and the risk of contamination during the replacement process, affecting the quality of the final product. Summary of the Invention

[0004] The purpose of this invention is to address the problems of low efficiency in stepwise preparation, uneven foam preparation, and cumbersome process of changing foam fineness in existing preparation devices, and to propose a composite hardening foam preparation for varicose veins and its preparation device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A composite sclerosing foam preparation for varicose veins and its preparation apparatus include a base, a homogenizing shell on top of the base, a stirring shell on top of the homogenizing shell, a discharge pipe connected to the side wall of the homogenizing shell, a foaming mechanism including a frother disposed within the stirring shell, the frother being configured to rotate around the axis of the stirring shell while simultaneously rotating on its own axis, the rotation of the frother mixing the liquid and generating foam, a homogenizing mechanism including a perforated plate disposed within the homogenizing shell, the outer wall of the perforated plate having multiple homogenizing holes of the same diameter, when the mixture passes through the homogenizing holes it breaks into microbubbles with smaller diameters, and a switching mechanism including a switching disc disposed within the homogenizing shell, the switching disc having multiple perforated plates embedded inside, the rotation of the switching disc switching between perforated plates of different diameters.

[0006] As a further description of the above technical solution: The foaming mechanism also includes a mounting plate, which is located on the top of the mixing shell. A support base is provided on one outer wall of the mounting plate. A protective cover is located on the top of the mixing shell. A rotating block is located on the top of the rotating block, which passes through the support base. A second motor is installed on the top of the protective cover, and the output end of the second motor is connected to one end of the rotating block.

[0007] As a further description of the above technical solution: The foaming mechanism also includes a limiting seat, which is located on the outer wall of one side of the mounting plate. The stirring shaft has its top end connected to the rotating block via a tube. The outer wall of the stirring shaft is provided with two limiting blocks. The outer wall of the limiting blocks and the inner wall of the limiting seat are both set as arc surfaces, and the outer wall of the limiting blocks is in contact with the inner wall of the limiting seat at the corresponding position.

[0008] As a further description of the above technical solution: The foaming mechanism also includes a first motor, which is installed on the top of the tube on one side of the rotating block, and the output end of the first motor is connected to the top of the stirring shaft. The foamer is sleeved on the outer wall of the bottom end of the stirring shaft.

[0009] As a further description of the above technical solution: The homogenizing mechanism also includes a drive wheel, the bottom of which is rotatably connected to the inner wall of the base bottom, and a third motor, which is mounted on the top of the base and whose output end is connected to the bottom end of the drive wheel.

[0010] As a further description of the above technical solution: The homogenizing mechanism also includes a central shaft, the bottom end of which is rotatably connected to the inner wall of the base bottom, a first driven wheel located outside the central shaft and meshing with a drive wheel, and a movable disk connected to the top of the central shaft, the outer wall of which has multiple flow-limiting holes around the central shaft.

[0011] As a further description of the above technical solution: The homogenizing mechanism also includes a baffle plate located below the movable plate, with the outer wall of the baffle plate fixedly connected to the inner wall of the homogenizing shell, and two through holes formed on the outer wall of the baffle plate, with the cross-sectional diameter of the through holes being the same as that of the perforated plate.

[0012] As a further description of the above technical solution: The switching mechanism further includes a threaded sleeve, which is sleeved outside the central shaft, a switching disc located at the top of the threaded sleeve, and a second driven wheel located outside the threaded sleeve, which meshes with the drive wheel.

[0013] As a further description of the above technical solution: The switching mechanism also includes a switching plate, which is sleeved on the outside of the drive wheel. A switching rod and a stroke groove are provided on one side of the outer wall of the switching plate. The stroke groove is opened on one side of the outer wall of the base, and the switching rod is slidably connected in the stroke groove.

[0014] As a further description of the above technical solution: The switching mechanism further includes a linkage wheel, which is rotatably connected to the top of the switching plate and meshes with a drive wheel; a first contact wheel, which is rotatably connected to the top of the switching plate and meshes with the linkage wheel; and a second contact wheel, which is rotatably connected to the top of the switching plate and meshes with the drive wheel.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, by setting up a foaming mechanism, the stirring shaft revolves around the axis of the rotating block, driving the foamer to revolve synchronously to uniformly mix different types of medicinal liquids. The rotation of the stirring shaft itself drives the foamer to rotate rapidly, stirring the mixture to generate foam. Mixing and foaming are carried out simultaneously, improving work efficiency.

[0016] 2. In this invention, by setting up a homogenizing mechanism, the foamed mixture is introduced into the homogenizing shell, and then the moving disk applies pressure to the mixture to make it quickly pass through the homogenizing holes opened on the outer wall of the perforated plate. The large bubbles are broken into small bubbles with uniform particle size through the small pores of the homogenizing holes, making the foam more delicate and uniform, and improving the product quality.

[0017] 3. In this invention, by setting a switching mechanism, there is no need to stop the machine to replace parts. The orifice plate with aligned through holes can be switched simply by moving the switching rod, so as to realize the rapid change of the homogeneous hole diameter, adapt to the requirements of foam preparation production with different fine densities, and improve the versatility of the device. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention; Figure 2 This is a schematic diagram showing the disassembled structure of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention. Figure 3 This is a schematic diagram of the foaming mechanism of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention. Figure 4 This is a partial cross-sectional schematic diagram of the foaming mechanism of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention. Figure 5This is a schematic diagram of the homogenization mechanism of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention. Figure 6 For the present invention Figure 5 A magnified structural diagram of part A in the middle; Figure 7 This is a schematic diagram of the switching mechanism of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention. Figure 8 This is a partial cross-sectional schematic diagram of the switching mechanism of a composite hardening foam preparation for varicose veins and its preparation device proposed in this invention.

[0019] Legend: 1. Base; 2. Homogenizing shell; 3. Stirring shell; 4. Protective cover; 5. Foaming mechanism; 501. Mounting plate; 502. Support base; 503. Limiting seat; 504. Rotating block; 505. Stirring shaft; 506. Limiting block; 507. Foamer; 508. First motor; 509. Second motor; 6. Homogenizing mechanism; 601. Drive wheel; 602. Central shaft; 603. First driven wheel 604. Wheel; 605. Moving disc; 606. Flow limiting hole; 607. Baffle plate; 608. Through hole; 609. Orifice plate; 6000. Third motor; 7. Switching mechanism; 701. Threaded sleeve; 702. Switching disc; 703. Second driven wheel; 704. Linkage wheel; 705. First contact wheel; 706. Second contact wheel; 707. Switching plate; 708. Switching rod; 709. Stroke groove; 8. Discharge pipe. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-4This invention provides a technical solution comprising: a base 1, a homogenizing shell 2 on top of the base 1, a stirring shell 3 on top of the homogenizing shell 2, a discharge pipe 8 connected to the side wall of the homogenizing shell 2, a foaming mechanism 5 including a bubbler 507 disposed within the stirring shell 3, the bubbler 507 being configured to rotate around the axis of the stirring shell 3 while simultaneously rotating on its own axis, the rotation of the bubbler 507 mixing the liquid and generating foam, a homogenizing mechanism 6 including a perforated plate 608 disposed within the homogenizing shell 2, the outer wall of the perforated plate 608 having multiple homogenizing holes of the same diameter, when the mixed liquid passes through the homogenizing holes it breaks into microbubbles with smaller diameters, and a switching mechanism 7 including a switching disk 702 disposed within the homogenizing shell 2, the switching disk 702 having multiple perforated plates 608 embedded inside, the rotation of the switching disk 702 switching between perforated plates 608 of different diameters.

[0022] The foaming mechanism 5 also includes a mounting plate 501, which is located on the top of the mixing shell 3. A support base 502 is provided on one outer wall of the mounting plate 501. A protective cover 4 is located on the top of the mixing shell 3. A rotating block 504 is located on the top of the rotating block 504, which is inserted into the support base 502. A second motor 509 is installed on the top of the protective cover 4, and the output end of the second motor 509 is connected to one end of the rotating block 504.

[0023] The foaming mechanism 5 also includes a limiting seat 503, which is located on the outer wall of one side of the mounting plate 501. A stirring shaft 505 is also included. The top end of the stirring shaft 505 is connected to the rotating block 504 through a tube. Two limiting blocks 506 are provided on the outer wall of the stirring shaft 505. The outer wall of the limiting block 506 and the inner wall of the limiting seat 503 are both set as arc surfaces, and the outer wall of the limiting block 506 is in contact with the inner wall of the limiting seat 503 at the corresponding position.

[0024] The foaming mechanism 5 also includes a first motor 508, which is installed on the top of the tube on one side of the rotating block 504, and the output end of the first motor 508 is connected to the top of the stirring shaft 505. The foamer 507 is sleeved on the outer wall of the bottom end of the stirring shaft 505.

[0025] Specifically: the second motor 509 drives the rotating block to rotate through the output end, and the stirring shaft 505 is connected to the side wall of the rotating block 504 through the tube. When the rotating block 504 rotates, the stirring shaft 505 rotates around the axis of the rotating block 504. The stirring shaft 505 is set at an angle, the cross-sectional shape of the limiting block 506 is semi-circular, and the cross-sectional shape of the groove inside the limiting seat 503 is also semi-circular. During the rotation of the stirring shaft 505 around the axis of the rotating block 504, the arc surface of the outer wall of the limiting block 506 contacts and slides relative to the arc surface of the limiting groove, so that the stirring range of the stirring shaft 505 is wider than that of the vertical setting, and the mixing between different liquids is more uniform. The first motor 508 drives the stirring shaft 505 to rotate through its output end. The bubbler 507 at the bottom of the stirring shaft 505 rotates synchronously with the stirring shaft 505. Multiple stirring filaments arranged around the outside of the bubbler 507 along its axis rapidly agitate the mixed liquid, causing air to mix into the mixture and generate bubbles. The bubbler 507 revolves around the axis of the rotating block 504 along with the stirring shaft 505, expanding the foaming range of the bubbler 507, preventing dead zones in foaming, and improving the density and yield of foam.

[0026] It should be further noted that the selection of the first motor 508 and the second motor 509 and the control unit in the above description are selected as needed. This part is well-known technology in the field and will not be described in detail here.

[0027] Please see Figures 5-6 and Figure 8 The homogenizing mechanism 6 also includes a drive wheel 601, the bottom of which is rotatably connected to the inner wall of the bottom of the base 1, and a third motor 609, which is mounted on the top of the base 1 and whose output end is connected to the bottom of the drive wheel 601.

[0028] The homogenizing mechanism 6 also includes a central shaft 602, the bottom end of which is rotatably connected to the inner wall of the bottom of the base 1, a first driven wheel 603, which is located outside the central shaft 602 and meshes with the drive wheel 601, and a movable disk 604, which is connected to the top of the central shaft 602. The outer wall of the movable disk 604 is provided with a plurality of flow-limiting holes 605 around the central shaft 602.

[0029] The homogenizing mechanism 6 also includes a baffle plate 606, which is located below the movable plate and whose outer wall is fixedly connected to the inner wall of the homogenizing shell 2. Two through holes 607 are opened on the outer wall of the baffle plate 606, and the cross-sectional diameter of the through holes 607 is the same as that of the perforated plate 608.

[0030] Specifically: the drive wheel 601 does not contact the second driven wheel 703, the teeth of the drive wheel 601 mesh with the teeth of the first driven wheel 603, there is damping between the outer wall of the threaded sleeve 701 and the inner wall of the base 1, when the switching rod 708 is located in the middle of the stroke groove 709, neither the first contact wheel 705 nor the second contact wheel 706 contacts the second driven wheel 703, and the threaded sleeve 701 does not rotate at this time; The third motor 609 drives the drive wheel 601 to rotate clockwise through its output end. The part of the drive wheel 601 located below the switching plate 707 meshes with the first driven wheel 603 and drives the first driven wheel 603 to rotate. The external thread on the outer wall of the central shaft 602 meshes with the internal thread on the inner wall of the threaded sleeve 701. The threaded sleeve 701 is stationary relative to the base 1. The central shaft 602 descends along the tube direction of the threaded sleeve 701. The central shaft 602 drives the moving plate to descend. After the mixture foams, it enters the homogenizing shell 2 from the bottom of the stirring shell 3, and then flows through the flow-limiting hole 605 through the moving plate to the space between the barrier plate 606 and the moving plate. The cross-sectional area of ​​the through hole 607 is the same as the cross-sectional area of ​​the orifice plate 608. When the moving plate descends, it pushes the foam through the homogenizing hole of the orifice plate 608. The homogenizing hole has small pores. When large bubbles pass through the homogenizing hole, they are broken into small bubbles. After the foam passes through the orifice plate 608, the bubble particle size distribution range is narrow and the size is uniform, which improves the quality of the foam preparation.

[0031] It should be further noted that the selection of the third motor 609 and the control unit in the above description are selected as needed. This part is well-known technology in the field and will not be elaborated here.

[0032] Please see Figures 6-7 The switching mechanism 7 also includes a threaded sleeve 701, which is sleeved outside the central shaft 602. The switching disk 702 is located at the top of the threaded sleeve 701. The second driven wheel 703 is located outside the threaded sleeve 701 and meshes with the drive wheel 601.

[0033] The switching mechanism 7 also includes a switching plate 707, which is sleeved on the outside of the drive wheel 601. A switching rod 708 and a stroke groove 709 are provided on one side of the outer wall of the switching plate 707. The stroke groove 709 is opened on one side of the outer wall of the base 1, and the switching rod 708 is slidably connected in the stroke groove 709.

[0034] The switching mechanism 7 also includes a linkage wheel 704, which is rotatably connected to the top of the switching plate 707 and meshes with the drive wheel 601; a first contact wheel 705, which is rotatably connected to the top of the switching plate 707 and meshes with the linkage wheel 704; and a second contact wheel 706, which is rotatably connected to the top of the switching plate 707 and meshes with the drive wheel 601.

[0035] Specifically: the switching lever 708 is moved to the left of the travel groove 709, the switching lever 708 drives the switching plate 707 to rotate clockwise, the first contact wheel 705 contacts and meshes with the second driven wheel 703, when the third motor 609 drives the drive wheel 601 to rotate clockwise, the drive wheel 601 drives the linkage wheel 704 to rotate counterclockwise, the linkage wheel 704 drives the first contact wheel 705 to rotate clockwise, the first contact wheel 705 drives the second driven wheel 703 to rotate counterclockwise, the second driven wheel 703 drives the threaded tube to rotate counterclockwise, the threaded tube drives the switching disc 702 to rotate counterclockwise synchronously, the four perforated plates 608 embedded in the switching disc 702 are symmetrically arranged in two groups, the homogeneous hole diameters of the two groups of perforated plates 608 are different, the rotation of the switching disc 702 causes the perforated plates 608 with the through hole 607 to switch, changing the fineness of the foam homogeneity; Move the switching lever 708 to the right of the travel groove 709. The second contact wheel 706 contacts and engages with the second driven wheel 703. When the third motor 609 drives the drive wheel 601 to rotate clockwise, the drive wheel 601 drives the second contact wheel 706 to rotate counterclockwise. The second contact wheel 706 drives the second driven wheel 703 to rotate clockwise. The second driven wheel 703 drives the threaded tube to rotate clockwise. The threaded tube drives the switching disc 702 to rotate clockwise synchronously, resetting the position of the orifice plate 608.

[0036] Working principle: When in use, the operator starts the first motor 508 and the second motor 509 of the bubble mechanism. Then, the operator injects the liquid to be mixed into the stirring shell 3 to mix the liquid and make it foam. After the bubble mechanism 5 has been running for a period of time, the operator turns off the first motor 508 and the second motor 509. When it is necessary to increase the foam fineness, the operator moves the switching rod 708 to the left and starts the third motor 609. The moving plate descends and presses the foam through the orifice plate 608. After homogenization, the foam is discharged from the discharge pipe 8. The operator collects the foam preparation from the discharge pipe 8. When it is necessary to decrease the foam fineness, the operator moves the switching rod 708 to the right and repeats the above operation.

[0037] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be 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 invention according to the specific circumstances.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A composite sclerosing foam preparation for varicose veins and its preparation apparatus, comprising a base (1), characterized in that, The base (1) is provided with a homogenizing shell (2) at the top, and a stirring shell (3) is provided at the top of the homogenizing shell (2). The side wall of the homogenizing shell (2) is connected to a discharge pipe (8). The foaming mechanism (5) includes a foamer (507) disposed in the stirring shell (3). The foamer (507) is configured to rotate around the axis of the stirring shell (3) while rotating on its own axis. The rotation of the foamer (507) mixes the liquid medicine and generates foam. The homogenizing mechanism (6) includes a perforated plate (608) disposed in the homogenizing shell (2). The outer wall of the perforated plate (608) is provided with a plurality of homogenizing holes of the same diameter. When the mixture passes through the homogenizing holes, it breaks into microbubbles with smaller diameters. The switching mechanism (7) includes a switching disk (702) disposed in the homogeneous shell (2). The switching disk (702) is provided with a plurality of perforated plates (608). The switching disk (702) is rotated to switch perforated plates (608) with different apertures.

2. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 1, characterized in that, The foaming mechanism (5) further includes: Mounting plate (501), the mounting plate (501) is located on the top of the stirring shell (3), and a support seat (502) is provided on one side of the outer wall of the mounting plate (501). A protective cover (4) is provided on the top of the stirring shell (3); The rotating block (504) has its top inserted into the support base (502). The protective cover (4) has a second motor (509) installed on its top, and the output end of the second motor (509) is connected to one end of the rotating block (504).

3. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 2, characterized in that, The foaming mechanism (5) further includes: A limiting seat (503) is provided on one side of the outer wall of the mounting plate (501); A stirring shaft (505) is connected to a rotating block (504) at its top end via a tube. Two limiting blocks (506) are provided on the outer wall of the stirring shaft (505). The outer wall of the limiting block (506) and the inner wall of the limiting seat (503) are both set as arc surfaces, and the outer wall of the limiting block (506) is in contact with the inner wall of the limiting seat (503) at the corresponding position.

4. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 3, characterized in that, The foaming mechanism (5) further includes: The first motor (508) is installed on the top of the tube on one side of the rotating block (504), and the output end of the first motor (508) is connected to the top of the stirring shaft (505). The bubbler (507) is sleeved on the outer wall of the bottom end of the stirring shaft (505).

5. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 1, characterized in that, The homogenizing mechanism (6) further includes: A drive wheel (601) is rotatably connected to the bottom inner wall of the base (1); The third motor (609) is mounted on the top of the base (1), and the output end of the third motor (609) is connected to the bottom end of the drive wheel (601).

6. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 5, characterized in that, The homogenizing mechanism (6) further includes: A central shaft (602) is rotatably connected to the inner wall of the bottom of the base (1); The first driven wheel (603) is located outside the central shaft (602) and meshes with the drive wheel (601); The movable disk (604) is connected to the top of the central shaft (602), and the outer wall of the movable disk (604) is provided with a plurality of flow-limiting holes (605) around the central shaft (602).

7. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 6, characterized in that, The homogenizing mechanism (6) further includes: A barrier plate (606) is provided below the movable plate, and the outer wall of the barrier plate (606) is fixedly connected to the inner wall of the homogeneous shell (2). Through holes (607), two through holes (607) are formed on the outer wall of the barrier plate (606), and the cross-sectional diameter of the through holes (607) is the same as the cross-sectional diameter of the perforated plate (608).

8. The composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 1, characterized in that, The switching mechanism (7) further includes: A threaded sleeve (701) is fitted around the outside of the central shaft (602), and the switching disk (702) is located at the top of the threaded sleeve (701). The second driven wheel (703) is located outside the threaded sleeve (701) and meshes with the drive wheel (601).

9. A composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 5, characterized in that, The switching mechanism (7) further includes: A switching plate (707) is sleeved on the outside of the drive wheel (601), and a switching rod (708) is provided on one side of the outer wall of the switching plate (707). The travel groove (709) is opened on the outer wall of one side of the base (1), and the switching rod (708) is slidably connected in the travel groove (709).

10. A composite sclerosing foam preparation for varicose veins and its preparation apparatus according to claim 1, characterized in that, The switching mechanism (7) also includes; Linkage wheel (704), which is rotatably connected to the top of the switching plate (707), and meshes with the drive wheel (601); The first contact wheel (705) is rotatably connected to the top of the switching plate (707), and the first contact wheel (705) meshes with the linkage wheel (704); The second contact wheel (706) is rotatably connected to the top of the switching plate (707) and meshes with the drive wheel (601).

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