A microemulsion polymerization mixing drum

Abstract

The present invention discloses a microemulsion polymerization stirring drum, comprising a cylinder, a cavity provided in the cylinder, a top plate provided at the upper end of the cavity of the cylinder, a bottom plate provided at the lower end of the cavity of the cylinder, a stirring assembly provided between the bottom plate and the top plate, the stirring assembly being able to slide left and right along the bottom plate and the top plate, the stirring assembly comprising a main shaft, the main shaft being able to rotate around its own axis, the main shaft being provided with a main shaft inner hole, a connecting shaft being provided in the main shaft inner hole, the connecting shaft being inserted into the main shaft inner hole, the main shaft inner hole diameter being larger than the connecting shaft diameter, the connecting shaft outer wall being provided with a rotating component, the rotating component being able to intermittently drive the main shaft to rotate. In the present invention, a polymerization reaction occurs under high shear stirring, so that the dispersion of the emulsion is higher and the microemulsion is more easily formed.

Description

Technical Field

[0001] The invention relates to the technical field of polymer microemulsion polymerization reaction stirring equipment, in particular to a microemulsion polymerization stirring drum. Background Art

[0002] When polymer microemulsion is polymerized, it is more difficult to disperse the monomer in the aqueous solution (hydrophilic) than when conventional polymer emulsion is polymerized. It is necessary to rely on some additives (that is, surfactants) added during the polymerization to disperse it. If it is to be made more dispersed into a microemulsion, the device where the polymerization reaction occurs needs to provide greater shear force when stirring.

[0003] In current polymerization reaction devices, when stirring the emulsion, the stirring shaft is directly driven by a motor. During stirring, the motor drives the stirring component to rotate at a constant speed. Since the emulsion also flows at a certain flow rate under the drive of the stirring component, the shear force of the stirring component on the emulsion is insufficient when stirring at a constant speed, affecting the polymerization reaction effect of the microemulsion. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a microemulsion polymerization stirring drum with a large shear force, which is more suitable for microemulsion polymerization reactions.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A microemulsion polymerization stirring drum comprises a drum body, a cavity is provided in the drum body, a top plate is provided at the upper end of the cavity of the drum body, a bottom plate is provided at the lower end of the cavity of the drum body, a stirring assembly is provided between the bottom plate and the top plate, the stirring assembly can slide left and right along the bottom plate and the top plate, the stirring assembly comprises a main shaft, the main shaft can rotate around its own axis, the main shaft is provided with a main shaft inner hole, a connecting shaft is provided in the main shaft inner hole, the connecting shaft is inserted into the main shaft inner hole, the main shaft inner hole diameter is larger than the connecting shaft diameter, the connecting shaft outer wall is provided with a rotating component, the rotating component can intermittently drive the main shaft to rotate.

[0007] The outer wall of the upper end of the main shaft is connected to a slider 1 through a bearing, and the upper end of the slider 1 is slidably connected to the bottom of the top plate. The slider 1 can move left and right along the top plate. The inner wall of the lower end of the main shaft is connected to a slider 2 through a bearing, and the lower end of the slider 2 is slidably connected to the bottom plate. The slider 2 can move left and right along the bottom plate.

[0008] The bottom plate is provided with a groove, and a spring 1 is provided in the groove. The spring 1 is located on both sides of the slider 2. One end of the spring 1 abuts against the side wall of the groove, and the other end of the spring abuts against the outer wall of the slider 2.

[0009] A cover plate is provided on the upper end of the bottom plate, an elastic member is installed on the inner side of the cover plate, and the inner peripheral wall of the elastic member is in contact with the two outer peripheral walls of the sliding block.

[0010] The spindle moves back and forth left and right as it rotates.

[0011] The rotating component is a sleeve, the outer wall of the connecting shaft is sleeved into the sleeve, the sleeve can rotate with the connecting shaft, and the outer peripheral wall of the sleeve can be tangent to the inner peripheral wall of the inner hole of the main shaft.

[0012] The connecting shaft includes a convex ring located at the bottom, the bottom surface of the sleeve is in contact with the top surface of the convex ring, and the top surface of the sleeve is in contact with the bottom surface of the top plate.

[0013] The rotating component is an acceleration assembly, which includes a fixed ring. A pressure block is provided below the fixed ring and can move closer to or away from the fixed ring. The acceleration assembly also includes an acceleration disk. When the acceleration disk extends between the fixed ring and the pressure block, the upper end surface of the acceleration disk fits with the lower end surface of the fixed ring, and the lower end surface of the acceleration disk fits with the upper end surface of the pressure block.

[0014] The spindle inner hole axis is located on the right side of the spindle axis.

[0015] The acceleration component also includes a cam, which rotates along with the connecting shaft and can abut against the inner wall of the fixing ring.

[0016] The beneficial effects of the present invention are:

[0017] As the main shaft oscillates back and forth, the sleeve periodically generates rotational acceleration for the main shaft, causing the agitating element to periodically accelerate during stirring. The separation phase between the main shaft 41 and the sleeve 3 reduces the emulsion flow rate, providing greater shear force to the emulsion when the main shaft 41 accelerates again. Polymerization occurs under high shear force, making the emulsion more dispersible and more likely to form a microemulsion.

[0018] The setting of the spring 1 on the right side allows the sleeve to approach the inner wall of the inner hole of the main shaft until they come into contact, thereby reducing the impact force between the two and reducing the impact on the output end of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a cross-sectional view of embodiment 1;

[0020] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0021] Figure 3 The positional relationship between the sleeve and the main shaft in Example 1 Figure 1 ;

[0022] Figure 4 The positional relationship between the sleeve and the main shaft in Example 1 Figure 2 ;

[0023] Figure 5 is a cross-sectional view of Example 2;

[0024] Figure 6 for Figure 5 Enlarged view of point B in the middle;

[0025] Figure 7 It is a cross-sectional view of the cam and the connecting shaft in the second embodiment.

[0026] In the figure: cylinder 1, top cover 11, motor 2, connecting shaft 21, convex ring 211, sleeve 3, stirring assembly 4, main shaft 41, main shaft inner hole 411, stirring component 412, slider 1 42, protrusion 1 421, slider 2 43, protrusion 2 431, protrusion 3 432, bottom plate 5, groove 51, slide 1 52, top plate 6, slide 2 61, spring 1 7, cover plate 8, elastic member 81, acceleration assembly 9, fixing ring 91, cam 92, acceleration disk 93, pressure block 94, fixing seat 95, fixing seat boss 951, spring 2 96, cavity 97. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below with reference to embodiments and in conjunction with the accompanying drawings.

[0028] Example 1:

[0029] like Figure 1-Figure 4 As shown, a microemulsion polymerization stirring drum is used to stir the microemulsion.

[0030] like Figure 1 As shown, the microemulsion polymerization mixing drum includes a barrel 1 , the upper end of the barrel 1 is open, a cavity is provided in the barrel 1 , and a top cover 11 is installed on the upper end of the barrel 1 to seal the upper end of the barrel 1 .

[0031] like Figure 1 As shown, the motor 2 is mounted on the top end of the top cover 11, and the output end of the motor 2 is connected to a connecting shaft 21. The connecting shaft 21 is a cylindrical structure that passes through the top cover 11 and extends to the lower end of the top cover 11. The connecting shaft 21 includes a protruding ring 211 at the bottom, which extends outward along the outer peripheral wall of the connecting shaft 21 to form an annular structure.

[0032] like Figure 1 As shown, a top plate 6 is provided at the upper end of the cavity of the cylinder 1. The top plate 6 is flat. The outer side of the top plate 6 is fixed to the side wall of the cylinder 1. The upper end surface of the top plate 6 is in contact with the lower end surface of the top cover 11. A second slide groove 61 is provided at the bottom of the top plate 6. The length direction of the second slide groove 61 is as shown in FIG. Figure 1 The connecting shaft 21 passes through the top plate 6.

[0033] The bottom end of the container of the cylinder 1 is provided with a bottom plate 5, which is flat. The lower end surface of the bottom plate 5 is in contact with the inner wall of the bottom of the cylinder 1. The bottom plate 5 is provided with a groove 51. The groove 51 is concave downward along the upper end surface of the bottom plate 5. The length direction of the groove 51 is as follows: Figure 1The shown orientation is set left and right, and the bottom surface of the groove 51 is provided with a sliding groove 1 52, and the sliding groove 1 52 is arranged parallel to the sliding groove 2 61 and opposite to each other up and down.

[0034] A spring 7 is provided in the groove 51 . Two springs 7 are provided. The two springs 7 are respectively located on both sides of the length direction of the groove 51 . The outer sides of the two springs 7 respectively press against the left and right side walls of the groove 51 .

[0035] A stirring assembly 4 is disposed between the bottom plate 5 and the top plate 6. The stirring assembly 4 can slide left and right along the bottom plate 5 and the top plate 6. Specifically, the stirring assembly 4 includes a main shaft 41. The main shaft 41 is a cylindrical structure. The outer wall of the upper end of the main shaft 41 is connected to a slider 1 42 via a bearing. The slider 1 42 includes a protrusion 1 421 located at the upper end. The protrusion 1 421 extends upward from the upper end of the slider 1 42 to form a protrusion. The cross-sectional shape of the protrusion 1 421 matches the cross-sectional shape of the chute 2 61. The protrusion 1 421 is inserted into the chute 2 61. The insertion of the protrusion 1 421 into the chute 2 61 allows the slider 1 42 to slide left and right along the chute 2 61.

[0036] like Figure 2 As shown, the inner wall of the lower end of the main shaft 41 is connected to the second slider 43 via a bearing. The second slider 43 includes a second raised portion 431 at the upper end. The outer wall of the second raised portion 431 is connected to the inner wall of the main shaft 41 via a bearing. The main shaft 41 is coaxial with the first slider 42 and the second slider 43, and the main shaft 41 can rotate about its own axis.

[0037] The slider 2 43 also includes a raised portion 3 432 located at the lower end. The raised portion 3 432 protrudes along the bottom surface of the slider 2 43 . The cross-sectional dimensions of the raised portion 3 432 match the cross-sectional dimensions of the slide groove 1 52 . The raised portion 3 432 is inserted into the slide groove 1 52 so that the slider 2 43 can move left and right along the bottom plate 5 .

[0038] like Figure 2 As shown, a cover plate 8 is provided on the upper end of the bottom plate 5, and the bottom surface of the cover plate 8 is fitted with the upper end surface of the bottom plate 5. An elastic member 81 is installed on the inner side of the cover plate 8, and the elastic member 81 is a rubber sealing ring. The second slider 43 passes through the elastic member 81, and the inner peripheral wall of the elastic member 81 is fitted with the outer peripheral wall of the second slider 43. The groove 51 is isolated from the cavity of the cylinder 1 by the cover plate 8, the elastic member 81 and the second slider 43 to prevent the emulsion in the cavity of the cylinder 1 from flowing into the groove 51.

[0039] The two springs 1 7 are respectively located on both sides of the slider 2 43 , and the inner ends of the two springs 1 7 respectively press against the outer walls on the left and right sides of the slider 2 43 .

[0040] like Figure 1As shown, the main shaft 41 is provided with a main shaft inner hole 411, which extends vertically along the axis of the main shaft 41. The outer wall of the main shaft 41 is mounted with a stirring member 412, which extends outward along the outer wall of the main shaft 41. The stirring members 412 are evenly distributed along the circumference of the main shaft 41 and are arranged in layers. When the main shaft 41 rotates, the main shaft 41 drives the stirring members 412 to rotate, thereby stirring the emulsion in the cavity of the cylinder 1.

[0041] The connecting shaft 21 is inserted into the inner hole 411 of the main shaft, and the bottom of the connecting shaft 21 is located above the slider 2 43. Figure 3 As shown, the diameter of the main shaft inner hole 411 is larger than the diameter of the connecting shaft 21. Figure 1 、 3 As shown, the outer wall of the connecting shaft 21 is covered with a sleeve 3. The sleeve 3 is a cylindrical structure and can rotate coaxially with the connecting shaft 21. The sleeve 3 is made of rubber or other wear-resistant material. The bottom surface of the sleeve 3 is in contact with the top surface of the convex ring 211, and the top surface of the sleeve 3 is in contact with the bottom surface of the top plate 6 to prevent the sleeve 3 from moving up and down during rotation. The outer peripheral wall of the sleeve 3 can be tangent to the inner peripheral wall of the main shaft inner hole 411.

[0042] like Figure 1 、 3 As shown, when the main shaft 41 moves to the rightmost position (this position is the initial state, at this time the springs 1 7 on both sides are in a compressed state, at this time the main shaft 41 is coaxial with the cylinder 1, the axis of the connecting shaft 21 deviates from the main shaft 41 and is located to the left of the axis of the main shaft 41, and the axis of the connecting shaft 21 is parallel to the axis of the main shaft 41), in this state, the force of the left spring 1 7 on the slider 2 43 is greater than the force of the right spring 1 7 on the slider 2 43, so that the left end of the outer peripheral wall of the sleeve 3 is tangent to and tightly attached to the left end of the inner peripheral wall of the main shaft inner hole 411. Since the sleeve 3 has a certain elasticity, the sleeve 3 is slightly compressed. After the motor 2 is turned on, driven by the connecting shaft 21, the sleeve 3 rotates, and its outer wall generates friction on the inner wall of the main shaft inner hole 411. The friction is tangential along the inner wall of the main shaft inner hole 411, causing the main shaft 41 to rotate along its axis, and when the sleeve 3 rotates, the main shaft 41 is bounced to the left (as shown in FIG. Figure 4 As shown), the spring 17 on the left is compressed. Under the action of the spring 17, the spring 17 pushes the main shaft 41 to the right until the inner wall of the main shaft inner hole 411 contacts the sleeve 3. The sleeve 3 drives the main shaft 41 to rotate and pop open again, and the cycle continues.

[0043] As spindle 41 moves, its left-right travel is relatively short, equivalent to a short reciprocating oscillation. During this process, elastic member 81 adaptively contracts and rebounds to prevent the emulsion from leaking into chute 1 52. Midway through the rightward movement of spindle 41, the inner end of right spring 1 7 abuts against slider 2 43. As spindle 41 continues to move rightward, right spring 1 7 compresses and creates resistance against slider 2 43. This reduces the impact force between sleeve 3 and the inner wall of spindle inner bore 411 when they come into contact, thereby reducing the impact on the output end of motor 2.

[0044] Therefore, the main shaft 41 rotates while making a left-right reciprocating motion. When the sleeve 3 contacts the inner wall of the main shaft inner hole 411, the sleeve 3 applies a rotational driving force to the main shaft 41, causing it to accelerate its rotation. When the sleeve 3 separates from the inner wall of the main shaft inner hole 411, the main shaft 41 slows down due to the resistance of the emulsion. At this time, the flow of the emulsion in the cylinder 1 cavity also slows down accordingly (the emulsion has a certain viscosity, and after the main shaft 41 slows down, its flow rate slows down faster). When the inner wall of the main shaft inner hole 411 contacts the sleeve 3 again, the main shaft 41 accelerates again. While the main shaft 41 oscillates back and forth, the sleeve 3 periodically generates power to accelerate the main shaft 41, causing the stirring component 412 to generate periodic stirring acceleration during stirring. The separation stage of the main shaft 41 and the sleeve 3 is used to reduce the emulsion flow rate, so that a greater shear force is provided to the emulsion when the main shaft 41 accelerates again. The polymerization reaction occurs under high shear force stirring, making the emulsion more dispersible and easier to form microemulsion.

[0045] Example 2: Further improvements are made based on Example 1.

[0046] like Figure 5-7 As shown, the connecting shaft 21 is coaxially arranged with the cylinder body 1 , and the axis of the main shaft inner hole 411 is not coaxial with the axis of the main shaft 41 , but is located to the right of the axis of the main shaft 41 .

[0047] An acceleration component 9 is provided in the spindle inner hole 411, and two acceleration components 9 are provided above and below. Figure 6 As shown, the acceleration assembly 9 includes a retaining ring 91 and a retaining seat 95 located below the retaining ring 91. The retaining ring 91 is a circular ring structure, and the outer wall of the retaining ring 91 is in contact with and fixed to the inner wall of the spindle inner bore 411. The retaining seat 95 includes a retaining seat boss 951. The bottom of the retaining seat 95 is a circular disc structure, and the outer wall of the retaining seat 95 is in contact with and fixed to the inner wall of the spindle inner bore 411. The retaining seat boss 951 extends upward from the upper end surface of the bottom of the retaining seat 95 to form an annular shape. The outer diameter of the retaining seat boss 951 is smaller than the outer diameter of the retaining seat 95.

[0048] The outer wall of the fixed seat boss 951 is slidably connected with a pressure block 94, which is a ring-shaped structure. The outer wall of the fixed seat boss 951 is also covered with a spring 2 96. The bottom of the spring 2 96 abuts against the upper end surface of the bottom of the fixed seat 95, and the top of the spring 2 96 abuts against the bottom of the pressure block 94. The pressure block 94 can slide up and down along the fixed seat boss 951.

[0049] The pressing block 94 is located below the fixing ring 91 and is disposed opposite to each other in the upper and lower directions. A cavity 97 is formed between the pressing block 94 and the fixing ring 91 .

[0050] The inner side of the fixing ring 91 is abutted with a cam 92, and the cam 92 is inserted into the connecting shaft 21 through an interference fit. The outer wall of the cam 92 can abut against the inner wall of the fixing ring 91, and the cam 92 rotates coaxially with the connecting shaft 21. The shape of the cam 92 is as follows Figure 7 As shown, one side of the cam 92 is a semicircular structure, and the other side is an elliptical structure. The radius of the semicircular side of the cam 92 is smaller than the radius of the elliptical side.

[0051] The acceleration assembly 9 further includes an acceleration disk 93 . The acceleration disk 93 is a circular disk structure. The acceleration disk 93 is inserted into the connecting shaft 21 and fixed.

[0052] like Figure 6 As shown, when one end of the semicircular structure of cam 92 abuts against retaining ring 91, a gap exists between the other end of the elliptical structure of cam 92 and retaining ring 91. Since the axis of spindle inner bore 411 is located to the right of the axis of spindle 41, the semicircular end of cam 92 is located to the left of connecting shaft 21, while the elliptical end is located to the right of connecting shaft 21. Furthermore, the outer end of accelerator disc 93 is located within cavity 97, and the upper and lower ends of accelerator disc 93 abut against the lower end of retaining ring 91 and the upper end of pressure block 94, respectively. Retaining ring 91 and pressure block 94 exert pressure on accelerator disc 93 from above and below. In this state, connecting shaft 21 and spindle 41 are coaxial.

[0053] When the connecting shaft 21 rotates, the cam 92 rotates, and the acceleration disk 93 rotates at the same time. Driven by the acceleration disk 93, the main shaft 41 rotates along its own axis.

[0054] When one end of the elliptical structure of the cam 92 rotates from the right to the left, it pushes the fixing ring 91 to move leftward, thereby moving the main shaft 41 to the left, and in this process, the main shaft 41 is thrown out, the acceleration disk 93 leaves the cavity 97, and the left spring 7 is compressed.

[0055] Under the elastic force of left spring 1 (7), spindle 41 moves rightward until the inner wall of retaining ring 91 contacts cam 92. When the inner wall of retaining ring 91 contacts the semicircular structure of cam 92, the outer end of accelerator plate 93 inserts into cavity 97, pushing pressure block 94 downward, compressing spring 2 (96). Accelerator plate 93 rotates, accelerating spindle 41. When cam 92 again swings spindle 41 to the left, accelerator plate 93 leaves cavity 97. Due to the resistance of the emulsion in cylinder 1, spindle 41 slows down, reducing the stirring rate. Throughout this process, the speed of connecting shaft 21 always exceeds that of spindle 41.

[0056] During the rightward movement of the main shaft 41, when the inner wall of the fixing ring 91 contacts the cam 92, if the contact end of the cam 92 with the inner wall of the fixing ring 91 is the elliptical end of the cam 92, the fixing ring 91 and the cam 92 abut from the elliptical end to the semicircular end, and the main shaft 41 and the fixing ring 91 continue to move rightward until the acceleration disk 93 enters the cavity 97. If the contact end of the cam 92 with the inner wall of the fixing ring 91 is the semicircular end of the cam 92, the acceleration disk 93 directly enters the cavity 97.

[0057] Simply put, when the acceleration disk 93 enters the cavity 97, the main shaft 41 accelerates and rotates. Compared with the acceleration method in Example 1, the acceleration disk 93 has a longer contact time with the fixing ring 91 and the pressure block 94 after entering the cavity 97, so the acceleration effect is better; when the acceleration disk 93 leaves the cavity 97, the main shaft 41 decelerates and rotates.

[0058] When the acceleration disk 93 accelerates the spindle 41 , the shear force of the stirring component 412 on the emulsion is increased, and a polymerization reaction occurs under the high shear force stirring, so that the emulsion has higher dispersibility and is easier to form a microemulsion.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microemulsion polymerization mixing drum, characterized in that: The invention comprises a cylinder (1), wherein a cavity is provided in the cylinder (1), a top plate (6) is provided at the upper end of the cavity of the cylinder (1), a bottom plate (5) is provided at the lower end of the cavity of the cylinder (1), a stirring assembly (4) is provided between the bottom plate (5) and the top plate (6), the stirring assembly (4) can slide left and right along the bottom plate (5) and the top plate (6), the stirring assembly (4) comprises a main shaft (41), the main shaft (41) can rotate around its own axis, the main shaft (41) is provided with a main shaft inner hole (411), a connecting shaft (21) is provided in the main shaft inner hole (411), the connecting shaft (21) is inserted into the main shaft inner hole (411), the diameter of the main shaft inner hole (411) is larger than the diameter of the connecting shaft (21), and a rotating component is provided on the outer wall of the connecting shaft (21), and the rotating component can intermittently drive the main shaft (41) to rotate; The outer wall of the upper end of the main shaft (41) is connected to a slider (42) through a bearing, the upper end of the slider (42) is slidably connected to the bottom of the top plate (6), and the slider (42) can move left and right along the top plate (6); the inner wall of the lower end of the main shaft (41) is connected to a slider (43) through a bearing, the lower end of the slider (43) is slidably connected to the bottom plate (5), and the slider (43) can move left and right along the bottom plate (5); The bottom plate (5) is provided with a groove (51), a spring (7) is provided in the groove (51), the spring (7) is located on both sides of the slider (43), one end of the spring (7) abuts against the side wall of the groove (51), and the other end of the spring (7) abuts against the outer wall of the slider (43); The rotating component is a sleeve (3), the outer wall of the connecting shaft (21) is inserted into the sleeve (3), the sleeve (3) can rotate along with the connecting shaft (21), and the outer peripheral wall of the sleeve (3) can be tangent to the inner peripheral wall of the main shaft inner hole (411); The connecting shaft (21) includes a convex ring (211) located at the bottom, the bottom surface of the sleeve (3) is in contact with the top surface of the convex ring (211), and the top surface of the sleeve (3) is in contact with the bottom surface of the top plate (6); The main shaft (41) moves back and forth when rotating; The connecting shaft (21) is coaxially arranged with the cylinder (1), the axis of the main shaft inner hole (411) is not coaxial with the axis of the main shaft (41), and the axis of the main shaft inner hole (411) is located on the right side of the axis of the main shaft (41).

2. A microemulsion polymerization mixing drum according to claim 1, characterized in that: A cover plate (8) is provided at the upper end of the bottom plate (5), an elastic member (81) is installed on the inner side of the cover plate (8), and the inner peripheral wall of the elastic member (81) is in contact with the outer peripheral wall of the second slider (43).

3. A microemulsion polymerization mixing drum according to claim 1, characterized in that: An acceleration assembly (9) is provided in the spindle inner hole (411), and two acceleration assemblies (9) are provided above and below. The acceleration assembly (9) includes a fixing ring (91) and a fixing seat (95) located below the fixing ring (91). The fixing ring (91) is a circular ring structure. The outer wall of the fixing ring (91) is fitted and fixed to the inner wall of the spindle inner hole (411). The fixing seat (95) includes a fixing seat boss (951). The bottom of the fixing seat (95) is a disc structure. The outer wall of the fixing seat (95) is fitted and fixed to the inner wall of the spindle inner hole (411). The fixing seat boss (951) extends upward along the upper end surface of the bottom of the fixing seat (95) to form a ring shape. The outer diameter of the fixing seat boss (951) is smaller than the outer diameter of the fixing seat (95). The outer wall of the fixed seat boss (951) is slidably connected with a pressure block (94), and the pressure block (94) is an annular structure. The outer wall of the fixed seat boss (951) is covered with a second spring (96), and the bottom of the second spring (96) abuts against the upper end surface of the bottom of the fixed seat (95), and the top of the second spring (96) abuts against the bottom of the pressure block (94). The pressure block (94) can slide up and down along the fixed seat boss (951); The pressing block (94) is located below the fixing ring (91) and is arranged opposite to each other up and down, and a cavity (97) is formed between the pressing block (94) and the fixing ring (91); A cam (92) is abutted against the inner side of the fixing ring (91), and the cam (92) is sleeved into the connecting shaft (21) with an interference fit. The outer wall of the cam (92) can abut against the inner wall of the fixing ring (91), and the cam (92) rotates coaxially with the connecting shaft (21). One side of the cam (92) is a semicircular structure, and the other side is an elliptical structure. The radius of the semicircular side of the cam (92) is smaller than the radius of the elliptical side. The acceleration assembly (9) further comprises an acceleration disc (93), which is a disc structure. The acceleration disc (93) is inserted into the connecting shaft (21) and fixed.

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