Novel dental turbine handpiece

Abstract

The invention discloses a novel dental turbine handpiece. Comprising a shell, a bur, a wheel disc, a turbine and a main shaft, a positioning shaft penetrates through the upper portion of the wheel disc and is arranged in the front-back direction, a machine needle is coaxially arranged at the front end of the positioning shaft and detachably connected with the positioning shaft, and the rear end of the positioning shaft is connected with the shell through a bearing. A square groove penetrates through the lower part of the wheel disc; the main shaft is arranged in the front-back direction, the turbine and the eccentric wheel are sequentially sleeved outside the main shaft in the axial direction, the eccentric wheel is located in the square groove and connected with the main shaft, a center hole of the turbine is connected with the main shaft, and the two ends of the main shaft are connected with the shell through bearings. According to the invention, hard tissue of teeth is cut while soft tissue of oral mucosa is prevented from being damaged, any surface of the machine needle can be used for working, the utilization rate of the cutter teeth on the machine needle is increased, and the service life of the machine needle is prolonged.

Description

Technical Field

[0001] The invention relates to the field of oral high-speed turbine mobile phones, in particular to a novel dental turbine mobile phone. Background Art

[0002] At present, dental high-speed turbine handpieces, as common treatment tools in the oral cavity, play an important role in clinical operations such as tooth preparation, restoration, and extraoral tooth extraction. However, during the operation, traditional high-speed turbine handpieces with rotation as the movement mode lack effective protection for oral soft tissues, making soft tissues including lips, buccal mucosa and lingual tissues vulnerable to damage during surgery, causing pain and discomfort to patients, and also affecting the accuracy and treatment effect of the surgery. Turbine handpieces with swinging movement mode can protect oral soft tissues to a certain extent while grinding teeth, but this type of handpiece has a narrow range of applications and has extremely high requirements for cutting angles and operator skills. If the cutting arc surface is offset from the cut surface, the needle will hit the cut surface at high frequency; and only the outer needle surface is involved in the cutting work, affecting the service life.

[0003] In clinical practice, many factors can increase the risk of soft tissue injury. For example, the patient's oral structure may be very complex, especially when the teeth are positioned far back or the mouth is not fully opened. The maxillofacial anatomy of specific populations, such as obese patients, can affect the visibility and accuracy of the operation. Children have poor patient compliance and are more likely to be uncooperative during treatment. In addition, improper operation by the doctor can lead to the accidental occurrence of iatrogenic injury.

[0004] While tools such as ultrasonic osteotome have emerged on the market, using high-frequency vibration or ultrasonic technology to precisely cut hard tissue while effectively protecting surrounding soft tissue from damage, their high cost and high wear and tear have limited their widespread clinical application. Overall, research in this area of ​​oral devices remains underdeveloped, both domestically and internationally, and improvements to high-speed turbine handpieces represent a promising area of ​​research. Summary of the Invention

[0005] To address the soft tissue protection issues associated with conventional high-speed turbine handpieces, this invention proposes a new dental turbine handpiece. By changing the motion mode of conventional turbine handpieces from traditional rotational motion to a reciprocating oscillating motion, this invention achieves the selective cutting effect of hard tissue (teeth) without damaging soft tissue within the oral cavity.

[0006] The present invention adopts the following technical solutions:

[0007] The dental turbine handpiece includes a shell and a needle, a wheel, a turbine and a main shaft arranged in the shell; a positioning shaft is provided through the upper part of the wheel disc, the positioning shaft is arranged in the front-to-back direction, a needle is coaxially arranged on the front end of the positioning shaft, the needle is detachably connected to the positioning shaft, and the rear end of the positioning shaft is connected to the shell through a bearing; a square groove is provided through the lower part of the wheel disc; the main shaft is arranged in the front-to-back direction, and a turbine and an eccentric wheel are sequentially sleeved on the outside along the axial direction, the eccentric wheel is located in the square groove, realizing the transmission connection between the main shaft and the wheel disc, the eccentric wheel is connected to the main shaft, the center hole of the turbine is connected to the main shaft, and both ends of the main shaft are connected to the shell through bearings.

[0008] The shell comprises a head body and a back cover, and the shell body and the back cover are connected in a snap-fit ​​manner.

[0009] The dental turbine handpiece also includes a first bearing and a second bearing, which are respectively arranged on the front and rear sides of the wheel disc. The first bearing and the second bearing are both mounted on the outside of the positioning shaft and have an interference fit with the positioning shaft. A first groove is provided on the inner surface of the front end of the shell body, and the first bearing is arranged in the first groove. A second groove is provided on the inner surface of the front end of the rear cover, and the second bearing is arranged in the second groove.

[0010] The dental turbine handpiece also includes a third bearing and a fourth bearing, which are respectively arranged on the front and rear sides of the lower part of the wheel disc. The third bearing and the fourth bearing are both mounted on the outside of the main shaft and have an interference fit with the main shaft. The third bearing, turbine, eccentric wheel and fourth bearing are arranged in sequence from front to back along the axial direction of the main shaft; a third groove is provided on the inner surface of the front end of the shell body, and the third groove is a two-step stepped groove. The turbine is arranged in the first-step stepped groove, and the third bearing is arranged in the second-step stepped groove. A fourth groove is provided on the inner surface of the front end of the rear cover, and the fourth bearing is arranged in the fourth groove; an air inlet and an air outlet are provided on the side wall of the first-step stepped groove of the third groove, and the outlet of the air inlet faces the turbine blades of the turbine. The inlet of the air inlet is connected to the external air source through the air pipe, and the air outlet is connected to the atmosphere through the air pipe.

[0011] The shell body is a cylinder with an axis parallel to the front-to-back direction. A cylindrical cavity with an open rear end is provided inside the shell body. After the shell body and the rear cover are connected, a closed cylindrical cavity is formed. The main body of the wheel disc is located in the cylindrical cavity and is spaced apart from the front and rear end surfaces of the cylindrical cavity.

[0012] The inner side wall of the head body is provided with a card slot, and the back cover is provided with a convex shaft extending forward. The card slots and convex shafts are the same in number and are aligned in a one-to-one correspondence. The convex shaft extends into the corresponding card slot and has an interference fit with the corresponding card slot.

[0013] A circular groove is formed through the front end surface of the shell, and the front end of the needle extends out of the shell from the circular groove. The center of the circular groove is located on the central axis of the positioning shaft and the needle.

[0014] A needle mounting groove is provided on the front end surface of the wheel positioning shaft, and the rear end portion of the needle is detachably embedded in the needle mounting groove.

[0015] The maximum rotation angle of the bur is 3° to 5°.

[0016] The rotation speed of the turbine is equal to the rotation frequency of the needle; the maximum rotation angle of the needle, the eccentricity of the eccentric wheel, and the wheelbase between the main shaft and the positioning shaft satisfy the following relationship:

[0017] α=2arcsin(e / l)

[0018] Where α is the maximum rotation angle of the needle, e is the eccentricity of the eccentric wheel, and l is the wheelbase between the main shaft and the positioning axis.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The dental turbine handpiece in the present invention uses the small-angle rotation of the needle around its own central axis as the working mode, and uses the needle surface as the cutting surface. It is suitable for various scenarios such as grinding and drilling, and has a wider range of applications. In addition, this small-angle rotation mode can use any needle surface to work, increasing the utilization rate of the cutting teeth on the needle and improving the service life of the needle.

[0021] 2. The dental turbine handpiece of the present invention has lower operating requirements and a wider range of applications.

[0022] In summary, the present invention changes the movement mode of the existing turbine handpiece, thereby achieving the ability to accurately cut hard tissues such as teeth during operation, while soft tissue can be pushed away during vibration due to its ductility and not be cut, thereby achieving a selective cutting effect that can cut hard tissue (teeth) without damaging the soft tissue inside the oral cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an exploded view of the internal structure of the dental handpiece of the present invention;

[0024] Figure 2 It is a three-dimensional schematic diagram of the internal structure of the dental handpiece of the present invention;

[0025] Figure 3 is a perspective view of the housing of a dental handpiece of the present invention;

[0026] Figure 4 It is a three-dimensional schematic diagram of the dental handpiece of the present invention;

[0027] Figure 5It is a front view of the head of the dental handpiece of the present invention;

[0028] Figure 6 It is a front view of the rear cover of the dental handpiece of the present invention;

[0029] Figure 7 is a cross-sectional view of the internal structure of the dental handpiece of the present invention;

[0030] Figure 8 is a first cross-sectional view of a wheel disc in a dental handpiece of the present invention;

[0031] Figure 9 is a second cross-sectional view of the wheel disc in the dental handpiece of the present invention;

[0032] Figure 10 is a cross-sectional view of an eccentric wheel in a dental handpiece of the present invention;

[0033] Figure 11 It is a front view of the extreme working positions of the eccentric wheel and the wheel disc in the dental mobile phone of the present invention, wherein (a) is the first extreme working position and (b) is the second extreme working position.

[0034] Among them, 1. needle, 2. first bearing, 3. wheel, 4. second bearing, 5. third bearing, 6. turbine, 7. main shaft, 8. fourth bearing, 9. head body, 10. back cover, 11. first groove, 12. second groove, 13. square groove, 14. third groove, 15. fourth groove, 16. circular groove, 17. needle mounting groove, 18. card slot, 19. convex shaft. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 and Figure 2 As shown, the dental turbine handpiece of the present invention comprises a housing and a needle 1, a wheel disc 3, a turbine 6 and a main shaft 7 arranged in the housing. A positioning shaft is provided through the upper portion of the wheel disc 3, the axis of which is arranged in the front-to-back direction, and a needle 1 is coaxially arranged at the front end of the positioning shaft. The needle 1 is detachably connected to the positioning shaft, and the rear end of the positioning shaft is connected to the housing via a bearing. A square groove 13 is provided through the lower portion of the wheel disc 3. The main shaft 7 is arranged in the front-to-back direction, and the turbine 6 and the eccentric wheel (such as Figure 10(As shown), the eccentric wheel is located in the square groove 13, achieving a transmission connection between the main shaft 7 and the wheel disc 3. The positioning shaft is fixedly connected to the wheel disc 3 or formed integrally, preferably integrally, with the eccentric wheel. The eccentric wheel is connected to the main shaft 7, and the center hole of the turbine 6 is connected to the main shaft 7. Both ends of the main shaft 7 are connected to the housing via bearings. The turbine 6 is driven by airflow and can drive the main shaft 7 to rotate synchronously. The eccentric wheel of the main shaft 7 is in constant contact with the square groove 13 of the wheel disc 3, thus maintaining a transmission connection between the eccentric wheel of the main shaft 7 and the wheel disc 3, thereby driving the wheel disc 3 and the needle 1 thereon to rotate slightly around the central axis of the needle 1.

[0037] like Figure 3 and Figure 4 As shown, the housing includes a head body 9 and a back cover 10, and the housing body 9 and the back cover 10 are connected in a snap-fit ​​manner.

[0038] like Figure 4 As shown, a circular groove 16 is provided through the front end surface of the shell, and the front end of the needle 1 extends out of the circular groove 16 and contacts the tooth after the shell. The center of the circular groove 16 is located on the central axis of the positioning shaft, the first bearing 2, the second bearing 4 and the needle 1.

[0039] Preferably, the diameter of the circular groove 16 is slightly larger than the diameter of the needle 1, so that the shape of the circular groove 16 can adapt to a certain deviation of the movement trajectory of the needle 1, ensuring that the needle 1 can move smoothly without unnecessary collision with the housing.

[0040] like Figure 1 and Figure 2 As shown, the dental turbine handpiece also includes a first bearing 2 and a second bearing 4, respectively positioned on the front and rear sides of the wheel disc 3. Both the first bearing 2 and the second bearing 4 are mounted on the exterior of the positioning shaft and have an interference fit with the shaft. The needle 1, the first bearing 2, the wheel disc 3, and the second bearing 4 are arranged in sequence from front to back along the axial direction of the positioning shaft. The second bearing 4 is mounted on the outer circumference of the rear end of the positioning shaft. The first and second bearings 2 and 4 cooperate with the positioning shaft of the wheel disc 3 to restrict the movement of the wheel disc 3 to swinging motion around the central axis of the positioning shaft, the needle 1, the first bearing 2, and the second bearing 4.

[0041] like Figure 5 As shown, a first groove 11 is provided on the inner surface of the front end of the housing body 9, and a first bearing 2 is arranged in the first groove 11. Figure 6 As shown, a second groove 12 is formed on the inner surface of the front end of the rear cover 10 , and a second bearing 4 is arranged in the second groove 12 .

[0042] Preferably, in the front-rear direction, the first groove 11 is consistent with the size of the first bearing 2 , and the second groove 12 is consistent with the size of the second bearing 4 .

[0043] like Figure 1 and Figure 2As shown, the dental turbine handpiece further includes a third bearing 5 and a fourth bearing 8, respectively arranged on the front and rear sides of the wheel disc 3. Both the third bearing 5 and the fourth bearing 8 are mounted on the exterior of the main shaft 7 and have an interference fit with the main shaft 7. The third bearing 5, turbine 6, eccentric, and fourth bearing 8 are arranged in sequence from front to back along the axial direction of the main shaft 7. The eccentric is located within the square groove 13 of the wheel disc 3, and the fourth bearing 8 is mounted on the outer periphery of the rear end of the main shaft 7. Specifically, the third bearing 5 and the fourth bearing 8 are used to limit the axial position of the main shaft 7. The outer periphery of the main shaft 7 cooperates with the center hole of the turbine 6 to form the drive module of the dental handpiece of the present invention.

[0044] like Figure 5 As shown, a third groove 14 is provided on the inner surface of the front end of the housing body 9. The third groove 14 is a two-step stepped groove. The turbine 6 is arranged in the first step groove. The turbine 6 does not directly contact the stepped groove, leaving a small gap. The third bearing 5 is arranged in the second step groove. Figure 6 As shown, a fourth groove 15 is formed on the inner surface of the front end of the rear cover 10 , and a fourth bearing 8 is arranged in the fourth groove 15 .

[0045] Preferably, in the front-rear direction, the first step groove of the third groove 14 is consistent with the size of the turbine 6 , the second step groove is consistent with the size of the third bearing 5 , and the fourth groove 15 is consistent with the size of the fourth bearing 8 .

[0046] like Figure 5 As shown, an air inlet and an air outlet are provided on the side wall of the first-level stepped groove of the third groove 14. The outlet of the air inlet faces the turbine blades of the turbine 6. The inlet of the air inlet is connected to the external air source through the air pipe, and the air outlet is connected to the atmosphere through the air pipe.

[0047] Optionally, the first bearing 2 is embedded in the first groove 11 , the second bearing 4 is embedded in the second groove 12 , the third bearing 5 is embedded in the second step groove of the third groove 14 , and the fourth bearing 8 is embedded in the fourth bearing 8 .

[0048] Optionally, the first bearing 2 is transitionally fitted with the first groove 11 , the second bearing 4 is transitionally fitted with the second groove 12 , the third bearing 5 is transitionally fitted with the third groove 14 , and the fourth bearing 8 is transitionally fitted with the fourth bearing 8 .

[0049] Specifically, the housing body 9 is a cylinder with an axis parallel to the front-to-back direction. It defines a cylindrical cavity with an open rear end. The front end of the cylindrical cavity serves as the inner surface of the front end of the housing body 9. When the housing body 9 is connected to the rear cover 10, a closed cylindrical cavity is formed. The rear end of the cylindrical cavity serves as the inner surface of the front end of the rear cover 10. The main body of the wheel disc 3 is located within the cylindrical cavity and maintains a certain distance from both the front and rear end surfaces of the cylindrical cavity.

[0050] Furthermore, a hollow pipe is provided in the columnar cavity, and two ends of the hollow pipe are respectively connected to the cooling water pipe and the water outlet.

[0051] Preferably, the implementation method of the snap-on connection between the shell body 9 and the back cover 10 is: a card slot 18 is provided on the inner side wall of the head body 9, and a convex shaft 19 extending forward is provided on the back cover 10. The number of the card slots 18 and the convex shaft 19 is the same and corresponds one to one. The convex shaft 19 is aligned with the corresponding card slot 18 in the axial direction, and the convex shaft 19 extends into the corresponding card slot 18 and has an interference fit with the corresponding card slot 18.

[0052] Preferably, if Figure 5 and Figure 6 As shown, the number of the grooves 18 and the number of the protruding shafts 19 are both 2. The two grooves 18 / protruding shafts 19 are arranged on the same radial straight line.

[0053] Preferably, if Figure 7 As shown, in the front-rear direction, the thickness of the eccentric wheel is greater than the thickness of the square groove 13.

[0054] like Figure 8 and Figure 9 As shown, a needle mounting groove 17 is provided on the front end surface of the positioning shaft of the wheel disc 3 , and the rear end portion of the needle 1 is detachably embedded in the needle mounting groove 17 .

[0055] Optionally, the rear end portion of the needle 1 is detachably embedded in the needle mounting groove 17 in an embodiment in which the rear end portion of the needle 1 is interference fit with the needle mounting groove 17 .

[0056] Preferably, if Figure 9 As shown, the needle mounting groove 17 does not completely penetrate the wheel disc 3.

[0057] Preferably, if Figure 8 and Figure 9 As shown, the needle mounting groove 17 is a circular groove.

[0058] Furthermore, both the positioning shaft and the main shaft 7 are provided with shaft shoulders for axial limiting of the bearing.

[0059] like Figure 10 As shown, the diameter of the eccentric wheel on the main shaft 7 is slightly smaller than the width of the square groove 13, ensuring reliable contact between the eccentric wheel and the square groove, thereby achieving the effect of driving the wheel disc 7 to move smoothly.

[0060] The working process of the dental turbine handpiece of the present invention is specifically as follows:

[0061] When an external gas source provides power to turbine 6 (typically via high-speed gas), turbine 6 itself rotates at high speed (the axis of rotation being the central axis of turbine 6). Due to the interference fit between main shaft 7 and the center hole of turbine 6, main shaft 7 rotates along with turbine 6, and the eccentric on main shaft 7 also rotates around the central axis of turbine 6, ultimately transmitting the motion of turbine 6 to the eccentric on main shaft 7. During this process, the eccentric's speed and direction of rotation should be the same as those of turbine 3.

[0062] The eccentric wheel on the main shaft 7 rotates continuously within the square groove 13 at the bottom of the wheel disc 3, driving the wheel disc 3 to swing at a limited angle about the central axis defined by the rolling bearings 2 and 4, converting the main shaft 7's own circular motion into a small-angle swing of the wheel disc 3. Simultaneously, the needle 1, removably mounted on the wheel disc 3, rotates synchronously with the wheel disc 3 at a limited angle. This achieves the ideal high-frequency rotation of the needle within a certain angle, with the turbine speed (r / s) equal to the needle's swing frequency (Hz).

[0063] When the bur 1 contacts the patient's teeth, it can cut off the hard teeth. When the doctor accidentally contacts the bur 1 with the oral soft tissue, the small angle rotation of the bur 1 plays a selective cutting role and will not damage the oral soft tissue with good ductility.

[0064] like Figure 11 As shown, the rotation direction of the needle 1 changes alternately between clockwise and counterclockwise according to the swing direction of the wheel 3.

[0065] Among them, the first bearing 2 and the second bearing 4 are respectively embedded in the first groove 11 and the second groove 12 inside the shell, so that the wheel 3 can swing at a small angle around the common axis of the first bearing 2, the second bearing 4, the positioning shaft and the needle 1, thereby driving the needle 1 to rotate at a small angle.

[0066] Preferably, the maximum rotation angle of the needle 1 is 3° to 5°, wherein the maximum rotation angle refers to the maximum angle that the needle 1 can rotate through when rotating.

[0067] The maximum rotation angle of the needle 1, the eccentricity of the eccentric wheel, and the wheelbase between the main shaft 7 and the positioning shaft satisfy the following relationship:

[0068] α=2arcsin(e / l)

[0069] Wherein, α represents the maximum rotation angle of the needle 1, e represents the eccentricity of the eccentric wheel, and l represents the wheelbase between the main shaft 7 and the positioning axis.

[0070] The above specific embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A new type of dental turbine handpiece, characterized by: The dental turbine handpiece comprises a housing and a turning needle (1), a wheel disc (3), a turbine (6) and a main shaft (7) arranged in the housing; a positioning shaft is provided through the upper part of the wheel disc (3), the positioning shaft is arranged in the front-to-back direction, a turning needle (1) is coaxially arranged at the front end of the positioning shaft, the turning needle (1) is detachably connected to the positioning shaft, and the rear end of the positioning shaft is connected to the housing via a bearing; a square groove (13) is provided through the lower part of the wheel disc (3); the main shaft (7) is arranged in the front-to-back direction, and a turbine (6) and an eccentric wheel are sequentially sleeved on the outside along the axial direction, the eccentric wheel is located in the square groove (13), the eccentric wheel is connected to the main shaft (7), the center hole of the turbine (6) is connected to the main shaft (7), and both ends of the main shaft (7) are connected to the housing via bearings.

2. The new dental turbine handpiece according to claim 1 is characterized in that: The shell comprises a head body (9) and a back cover (10), and the shell body (9) and the back cover (10) are connected in a snap-fit ​​manner.

3. The new dental turbine handpiece according to claim 2, characterized in that: The dental turbine handpiece further comprises a first bearing (2) and a second bearing (4), which are respectively arranged on the front and rear sides of the wheel disc (3); the first bearing (2) and the second bearing (4) are both mounted on the outside of the positioning shaft and are interference fit with the positioning shaft; a first groove (11) is provided on the inner surface of the front end of the shell body (9), and the first bearing (2) is arranged in the first groove (11); a second groove (12) is provided on the inner surface of the front end of the rear cover (10), and the second bearing (4) is arranged in the second groove (12).

4. The new dental turbine handpiece according to claim 2, characterized in that: The dental turbine handpiece further comprises a third bearing (5) and a fourth bearing (8), which are respectively arranged on the front and rear sides of the lower part of the wheel disc (3). The third bearing (5) and the fourth bearing (8) are both mounted on the outside of the main shaft (7) and are interference fit with the main shaft (7). The third bearing (5), the turbine (6), the eccentric wheel and the fourth bearing (8) are arranged in sequence from front to back along the axial direction of the main shaft (7); a third groove (14) is provided on the inner surface of the front end of the shell body (9), and the third groove (14) is a second-order groove. The stepped groove is provided with a turbine (6) in the first stepped groove, and a third bearing (5) in the second stepped groove. A fourth groove (15) is provided on the inner surface of the front end of the rear cover (10), and a fourth bearing (8) is provided in the fourth groove (15); an air inlet and an air outlet are provided on the side wall of the first stepped groove of the third groove (14), the outlet of the air inlet is directly opposite to the turbine blades of the turbine (6), the inlet of the air inlet is connected to an external air source through an air pipe, and the air outlet is connected to the atmosphere through the air pipe.

5. The new dental turbine handpiece according to claim 2 is characterized in that: The shell body (9) is a cylinder with an axis parallel to the front-to-back direction. A cylindrical cavity with an open rear end is provided inside the shell body (9). After the shell body (9) and the rear cover (10) are connected, a closed cylindrical cavity is formed. The main body of the wheel disc (3) is located in the cylindrical cavity and is spaced apart from the front and rear end surfaces of the cylindrical cavity.

6. The new dental turbine handpiece according to claim 2, characterized in that: The inner side wall of the head body (9) is provided with a card slot (18), and the rear cover (10) is provided with a convex shaft (19) extending forward. The card slots (18) and the convex shafts (19) are the same in number and correspond one to one. The convex shafts (19) extend into the corresponding card slots (18) and are interference-fitted with the corresponding card slots (18).

7. The new dental turbine handpiece according to claim 1 is characterized in that: A circular groove (16) is formed through the front end surface of the shell, and the front end of the needle (1) extends out of the shell from the circular groove (16). The center of the circular groove (16) is located on the central axis of the positioning shaft and the needle (1).

8. The new dental turbine handpiece according to claim 1 or 7, characterized in that: A turning needle mounting groove (17) is provided on the front end surface of the positioning shaft of the wheel disc (3), and the rear end portion of the turning needle (1) is detachably embedded in the turning needle mounting groove (17).

9. The new dental turbine handpiece according to claim 1 is characterized in that: The maximum rotation angle of the turning needle (1) is 3° to 5°.

10. The new dental turbine handpiece according to claim 1 or 9, characterized in that: The rotation speed of the turbine (6) is equal to the rotation frequency of the turning needle (1); the maximum rotation angle of the turning needle (1), the eccentricity of the eccentric wheel, and the wheelbase between the main shaft (7) and the positioning shaft satisfy the following relationship: α=2arcsin(e / l) Wherein, α represents the maximum rotation angle of the needle (1), e represents the eccentricity of the eccentric wheel, and l represents the wheelbase between the main shaft (7) and the positioning shaft.

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