Pipette and self-locking counting device thereof

Abstract

The embodiment of the invention discloses a pipettor and a self-locking counting device thereof. The self-locking counting device comprises a counting assembly, an indexing wheel, an indexing arm, a first self-locking structure and a second self-locking structure. The counting assembly comprises a first counting unit, and the first counting unit comprises a first number wheel capable of rotating. The dividing wheel and the first digital wheel rotate synchronously. The first end of the indexing arm is fixed, and the second end of the indexing arm abuts against the indexing wheel. The first self-locking structure is located on the abutting portion of the indexing arm and the indexing wheel and can limit rotation of the indexing wheel. The second self-locking structure is used for fixing the first end of the indexing arm. According to the pipettor and the self-locking counting device thereof in the embodiment of the invention, self-locking can be realized after counting while manual counting is realized, so that the accuracy of a counting result is ensured. And in the counting process, the counting assembly can easily overcome the limitation of the first self-locking structure and the second self-locking structure, so that an operator can more easily operate the manual pipettor.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipette counting, and particularly relates to a pipette and its self-locking counting device. Background Art

[0002] Pipettes are mainly used for operations such as liquid transfer and dispensing. They are one of the most commonly used instruments in laboratories and also one of the instruments most likely to affect experimental results. Currently, the commonly used pipettes are mainly manual pipettes. The implementation principle of manual pipettes is as follows: By rotating the volume adjustment knob, the piston stroke is changed, thereby realizing the adjustment of the liquid transfer volume. The piston stroke is mechanically linked to the mechanical counting wheel for reading. Since there is a corresponding relationship between the piston stroke and the counting wheel volume reading, when the piston stroke changes, the counting wheel reading also changes accordingly.

[0003] Currently, the counting devices of manual pipettes are divided into two categories: those with a self-locking device and those without a self-locking device. For manual pipettes without a self-locking device, the transmission components in the counting device are not easily stopped immediately at the end of counting, resulting in the inability to quickly adjust the counting device to the target value. For manual pipettes with a self-locking device, their structures are complex and the self-locking force is large. Operators need to provide a relatively large force to overcome the corresponding friction force, resulting in a poor hand feeling when operators use the pipette.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a pipette and its self-locking counting device, which can achieve manual counting and self-locking after counting.

[0006] To achieve the above purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0007] A self-locking counting device includes a counting component, a dividing wheel, a dividing arm, a first self-locking structure, and a second self-locking structure. The counting component includes a first counting unit, and the first counting unit includes a first digit wheel that can rotate. The dividing wheel rotates synchronously with the first digit wheel. The first end of the dividing arm is fixed, and the second end of the dividing arm abuts against the dividing wheel. The first self-locking structure is located at the abutting part of the dividing arm and the dividing wheel and can limit the rotation of the dividing wheel. The second self-locking structure is used to fix the first end of the dividing arm.

[0008] In one or more embodiments of the present invention, the indexing arm includes an indexing rod. The first self-locking structure includes a first locking protrusion provided at the end of the indexing rod, a plurality of second locking protrusions provided around the indexing wheel, and a locking groove provided between adjacent second locking protrusions. The self-locking counting device has a counting state and a stationary state. In the counting state, the indexing wheel rotates, and the first locking protrusion alternately abuts against the second locking protrusion and the locking groove. In the stationary state, the indexing wheel is stationary, and the first locking protrusion abuts against the locking groove.

[0009] In one or more embodiments of the present invention, the self-locking counting device further has a transition state. In the transition state, the indexing wheel has a tendency to be stationary. The self-locking counting device further includes a guiding structure. In the transition state, the guiding structure is used to guide the first locking protrusion into the locking groove, so that the self-locking counting device changes from the transition state to the stationary state. The guiding structure includes a first arc surface provided on the end surface of the first locking protrusion and a second arc surface provided on the end surface of the second locking protrusion.

[0010] In one or more embodiments of the present invention, the arc radius of the first arc surface is 0.5 - 1.5 mm.

[0011] In one or more embodiments of the present invention, a third arc surface is provided on one side and / or both sides of the indexing rod. The bending direction of the third arc surface is opposite to that of the first arc surface, and the arc radius of the third arc surface is 3 - 4 mm.

[0012] In one or more embodiments of the present invention, the indexing arm further includes a mounting portion provided at one end of the indexing arm. The indexing rod is fixed on the mounting portion or integrally formed therewith. The second self-locking structure includes a limiting block and an abutting block fixed on the mounting portion. The abutting block abuts against the limiting block, and the position of the limiting block is fixed.

[0013] In one or more embodiments of the present invention, the indexing arm is detachable.

[0014] In one or more embodiments of the present invention, the end surface where the abutting block abuts against the limiting block is arc-shaped, and the arc radius of this end surface is 0.5 - 1.5 mm.

[0015] In one or more embodiments of the present invention, there is an included angle between the abutting block and the indexing rod.

[0016] In one or more embodiments of the present invention, the first counting unit further includes a first driving gear, a main driving gear, and a first fixed shaft. The first driving gear is coaxially installed on the first fixed shaft with the first digital wheel and the indexing wheel and rotates synchronously. The main driving gear is meshed and connected with the first driving gear.

[0017] In one or more embodiments of the present invention, the first counting unit further includes a first carry gear, which is mounted on the first fixed shaft and rotates synchronously with the first digit wheel. The first carry gear is an incomplete gear. The counting assembly further includes a third counting unit, one or more second counting units, a second fixed shaft, and a plurality of transmission gears. The third counting unit is mounted on the first fixed shaft and includes a third digit wheel and a third driving gear that rotate synchronously. The second counting unit is mounted on the first fixed shaft and includes a second digit wheel, a second driving gear, and a second carry gear that rotate synchronously. The second carry gear is an incomplete gear. The plurality of transmission gears are mounted on the second fixed shaft. A single transmission gear meshes with a single third driving gear, and the transmission gear also meshes with the first carry gear or the second carry gear periodically.

[0018] In one or more embodiments of the present invention, the mounting portion is mounted on the second fixed shaft.

[0019] A pipette includes the above-mentioned self-locking counting device.

[0020] Compared with the prior art, the pipette and its self-locking counting device according to the embodiments of the present invention can achieve manual counting and self-locking after counting is completed, ensuring the accuracy of the counting result. And during the counting process, the counting assembly can easily overcome the limitations of the first self-locking structure and the second self-locking structure, making it easier for the operator to operate the manual pipette. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 It is a schematic three-dimensional structure diagram of the self-locking counting device in the embodiment of the present invention;

[0023] Figure 2 It is a schematic plan structure diagram of the self-locking counting device in the embodiment of the present invention;

[0024] Figure 3 It is a schematic structure diagram of the counting state of the self-locking counting device in the embodiment of the present invention;

[0025] Figure 4 It is a schematic structure diagram of the stationary state of the self-locking counting device in the embodiment of the present invention;

[0026] Figure 5Schematic plan view of the indexing arm in the embodiment of the present invention;

[0027] Figure 6 Schematic three-dimensional view of the indexing arm in the embodiment of the present invention.

[0028] Main reference numerals description: 1, counting assembly; 11, first counting unit; 111, first digit wheel; 112, first driving gear; 113, main driving gear; 114, first fixed shaft; 115, first carry gear; 12, second counting unit; 121, second digit wheel; 122, second driving gear; 123, second carry gear; 13, third counting unit; 131, third digit wheel; 132, third driving gear; 14, second fixed shaft; 15, transmission gear; 16, cover plate; 2, indexing arm; 21, indexing rod; 211, third arc surface; 22, first locking projection; 221, first arc surface; 23, mounting portion; 24, abutting block; 3, indexing wheel; 31, second locking projection; 311, second arc surface; 32, locking groove; 4, limiting block; 5, base. Detailed implementation manners

[0029] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] As Figures 1 to 6 shown, a self-locking counting device in an embodiment of the present invention includes a counting assembly 1, an indexing wheel 3, an indexing arm 2, a first self-locking structure, and a second self-locking structure. The counting assembly 1 includes a first counting unit 11, and the first counting unit 11 includes a rotatable first digit wheel 111. The indexing wheel 3 rotates synchronously with the first digit wheel 111. The first end of the indexing arm 2 is fixed, and the second end of the indexing arm 2 abuts against the indexing wheel 3. The first self-locking structure is located at the abutting portion of the indexing arm 2 and the indexing wheel 3 and can limit the rotation of the indexing wheel 3. The second self-locking structure is used to fix the first end of the indexing arm 2.

[0031] In this embodiment, a plurality of digits for facilitating the operator's observation are provided on the toroidal surface of the first digit wheel 111. During the counting process, the operator or other driving mechanisms drive the first digit wheel 111 to rotate. During this process, the first digit wheel 111 overcomes the limitations of the first self-locking structure and the second self-locking structure, and the first digit wheel 111 can rotate normally and perform counting. When the first digit wheel 111 stops counting and stops rotating, the rotation of the indexing wheel 3 is restricted by the first self-locking structure, and then the rotation of the first digit wheel 111 that rotates synchronously with the indexing wheel 3 is restricted, fixing the position of the stationary first digit wheel 111.

[0032] As Figure 3 and Figure 4 shown, the indexing arm 2 includes an indexing rod 21 with a certain elasticity. The first self-locking structure includes a first locking protrusion 22 provided at the end of the indexing rod 21, a plurality of second locking protrusions 31 arranged around the indexing wheel 3, and locking grooves 32 provided between adjacent second locking protrusions 31, so that the self-locking counting device of this embodiment has a counting state and a stationary state.

[0033] In the counting state, the indexing wheel 3 rotates continuously and has a tendency to transmit the rotation of the indexing wheel 3 to the indexing arm 2 through the first self-locking structure. However, due to the restriction of the second self-locking structure on the indexing arm 2, the indexing arm 2 cannot rotate, and then this movement tendency is converted into the elastic deformation of the indexing rod 21. Specifically, when the first locking protrusion 22 contacts the second locking protrusion 31, the indexing rod 21 is compressed to generate elastic deformation, and this elastic deformation force causes the first locking protrusion 22 to abut against the second locking protrusion 31. When the first locking protrusion 22 contacts the locking groove 32, the indexing rod 21 restores elastic deformation, and the elastic deformation force at this time causes the first locking protrusion 22 to abut against the locking groove 32, finally realizing the periodic alternate abutment of the first locking protrusion 21 between the second locking protrusion 31 and the locking groove 32.

[0034] In the stationary state, the counting assembly 1 stops counting, the indexing wheel 3 is stationary, and the first locking protrusion 22 abuts against the locking groove 32.

[0035] The self-locking counting device in this embodiment also has a transition state. In the transition state, the indexing wheel 3 has a tendency to be stationary. To prevent errors in counting when the indexing wheel 3 is stationary and the first locking protrusion 22 does not enter the locking groove 32, the self-locking counting device in this embodiment further includes a guiding structure. In the transition state, the guiding structure is used to guide the first locking protrusion 22 into the locking groove 32, so that the self-locking counting device changes from the transition state to the stationary state. Specifically, the guiding structure includes a first arc surface 221 provided on the end face of the first locking protrusion 22 and a second arc surface 311 provided on the end face of the second locking protrusion 31.

[0036] When the self-locking counting device of this embodiment finishes counting and is in a transitional state, the indexing wheel 3 is about to stop rotating. If the first locking protrusion 22 is exactly located within the locking groove 32, since the contact area between the first locking protrusion 22 and the locking groove 32 is relatively large and the formed structure is more stable, the remaining kinetic energy of the indexing wheel 3 cannot cause relative movement between the first locking protrusion 22 and the locking groove 32. Then the first locking protrusion 22 will abut within the locking groove 32 and consume the remaining kinetic energy of the indexing wheel 3, causing the indexing wheel 3 to stop rotating. When the indexing wheel 3 is about to stop rotating, if the first locking protrusion 22 is exactly abutting against the second locking protrusion 31, at this time, since the end faces of the abutting ends of the first locking protrusion 22 and the second locking protrusion 31 are respectively the first arc surface 221 and the second arc surface 311, the contact area between the two arc surfaces is relatively small and the structure formed by the two is relatively unstable. The indexing wheel 3 will then use the remaining kinetic energy to continue rotating until the first locking protrusion 22 is combined with the locking groove 32.

[0037] As Figure 5 shown, the arc radius of the first arc surface 221 is 0.5 - 1.5 mm. In particular, the arc radius of the first arc surface 221 can be set to 0.5 mm, 1 mm or 1.5 mm.

[0038] During the rotation of the indexing wheel 3, in order to reduce the resistance brought by the first self-locking structure, the third arc surface 211 is provided on one side and / or both sides of the indexing rod 21, and the bending direction of the third arc surface 211 is opposite to that of the first arc surface 221. After setting the third arc surface 211, the elastic deformation ability of the indexing rod 21 can be improved, thereby reducing the resistance encountered when the indexing wheel 3 rotates. Specifically, the third arc surface 211 can be provided on the side close to the first locking protrusion 22, or on the side far from the first locking protrusion 22, or the third arc surface 211 is provided at both of the above-mentioned positions. And, the arc radius of the third arc surface 211 can be set to 3 - 4 mm. In particular, it can be specifically set to 3 mm, 3.5 mm or 4 mm.

[0039] In one embodiment, the indexing arm 2 further includes a mounting portion 23 provided at one end of the indexing arm 2. The indexing rod 21 is fixed on the mounting portion 23 or integrally formed therewith. The second self-locking structure includes a limiting block 4 and an abutting block 24 fixed on the mounting portion 23. The abutting block 24 abuts against the limiting block 4, and the position of the limiting block 4 is fixed. The limiting block 4 and the abutting block 24 are in interference fit, and the structure formed by the two can limit the rotation of the mounting portion 23 and the indexing rod 21. Thus, when the indexing wheel 3 rotates, the indexing rod 21 can periodically generate elastic deformation, so that the first locking protrusion 22 alternately abuts between the second locking protrusion 31 and the locking groove 32.

[0040] Further, since the indexing rod 21 will undergo fatigue deformation after repeated deformation for a long time, and the first locking protrusion 22 will also be worn to a certain extent after being in contact with the indexing wheel 3 for a long time, the indexing arm 2 in this embodiment is detachable to facilitate the replacement of the damaged indexing arm 2. Specifically, the mounting portion 23 of the indexing arm 2 can be movably mounted on a fixed shaft, and then the second self-locking structure is used to prevent the indexing arm 2 from rotating. When the indexing arm 2 needs to be replaced, the mounting portion 23 of the indexing arm 2 is removed from the fixed shaft, and a new indexing arm 2 can be directly replaced.

[0041] Further, in order to enable the indexing arm 2 to still be precisely matched with the indexing wheel 3 after the indexing arm 2 is replaced, the end face where the abutting block 24 abuts against the limiting block 4 is set to be arc-shaped. The arc-shaped end face can enable the abutting block 24 to be in line contact with the limiting block 4, so that there is a relatively precise reference object for auxiliary positioning when replacing the indexing arm 2. This reference object is the contact line between the abutting block 24 and the limiting block 4. Specifically, the arc radius of the end face where the abutting block 24 contacts the limiting block 4 can be set to 0.5 - 1.5 mm. In particular, it can be specifically set to 0.5 mm, 0.8 mm, 1 mm or 1.5 mm.

[0042] Further, there is an angle between the abutting block 24 and the indexing rod 21, that is, the abutting block 24 and the indexing rod 21 can form angles at different angles with the axis of the mounting portion 23. Therefore, when the mounting portion 23 is arranged in the vertical direction, the abutting block 24 and the indexing rod 21 can be arranged at the same height of the mounting portion 23, thereby reducing the overall occupied space of the mounting portion 23, the abutting block 24 and the indexing rod 21, and reducing the overall volume of the self-locking counting device in this embodiment.

[0043] As Figures 2 to 4 shown, the first counting unit 11 in this embodiment further includes a first driving gear 112, a main driving gear 113 and a first fixed shaft 114. The first driving gear 112 is coaxially mounted on the first fixed shaft 114 with the first digit wheel 111 and the indexing wheel 3 and rotates synchronously. The main driving gear 113 is meshed with the first driving gear 112. By driving the main driving gear 113, the first digit wheel 111 can be driven to rotate and count.

[0044] Further, in order to increase the counting range of the self-locking counting device of this embodiment, the first counting unit 11 further includes a first carry gear 115. The first carry gear 115 is mounted on the first fixed shaft 114 and rotates synchronously with the first digit wheel 111. The first carry gear 115 is an incomplete gear. The counting assembly 1 further includes one or more second counting units 12, third counting units 13, a second fixed shaft 14, and a plurality of transmission gears 15. The third counting unit 13 is mounted on the first fixed shaft 114. The third counting unit 13 includes a third digit wheel 131 and a third driving gear 132 that rotate synchronously. The second counting unit 12 is mounted on the first fixed shaft 114. The second counting unit 12 includes a second digit wheel 121, a second driving gear 122, and a second carry gear 123 that rotate synchronously. The second carry gear 123 is an incomplete gear. The transmission gears 15 are mounted on the second fixed shaft 14. A single transmission gear 15 meshes with a single third driving gear 132, and this transmission gear 15 also meshes with the first carry gear 115 or the second carry gear 123 periodically.

[0045] During specific counting, when the first digit wheel 111 rotates one full circle, the first carry gear 115 will mesh with the corresponding transmission gear 15 once, driving the transmission gear 15 to rotate a certain angle. At the same time, this transmission gear 15 synchronously drives the second driving gear 122 meshing with it to rotate a certain angle, and the second digit wheel 121 rotates synchronously with the second driving gear 122, causing the number observable by the operator on the second digit wheel 121 to change to achieve a carry. Similarly, when this second digit wheel 121 intermittently rotates one full circle, it will drive the next second digit wheel 121 or the third digit wheel 131 to rotate a certain angle to achieve a carry.

[0046] Further, in order to save the occupied space of the self-locking counting device of this embodiment of the present invention and streamline its transmission and connection structure, the mounting portion 23 is mounted on the second fixed shaft 14. To facilitate the disassembly of the mounting portion 23, corresponding shaft holes can be provided on the mounting portion 23 and combined with the second fixed shaft 14.

[0047] Further, the ends of the first fixed shaft 114, the second fixed shaft 14, and the limiting block 4 are all fixed on the base 6, and a cover plate 16 is also mounted on the other ends of the first fixed shaft 114 and the second fixed shaft 14.

[0048] In another embodiment of the present invention, a pipette is further provided. This pipette includes the above-mentioned self-locking counting device and other necessary components for achieving the pipetting effect.

[0049] As can be seen from the technical solutions of the above embodiments, the self-locking counting device according to an embodiment of the present invention can achieve manual counting while being able to achieve self-locking after counting, preventing external forces from affecting the counting result and ensuring the accuracy of the counting result. Moreover, during the counting process, the counting component can easily overcome the limitations of the first self-locking structure and the second self-locking structure, making it easier for the operator to manually drive the counting component.

[0050] The self-locking counting device provided by an embodiment of the present invention can be a general-purpose device, which can be applied not only to manual pipettes but also to other devices that require counting functions and self-locking functions after counting.

[0051] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0052] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A self-locking counting device, characterized in that, Comprising: A counting component (1), including a first counting unit (11), and the first counting unit (11) includes a first digit wheel (111) capable of rotating; A indexing wheel (3), rotating synchronously with the first digit wheel (111); An indexing arm (2), with its first end fixed and its second end abutting against the indexing wheel (3); A first self-locking structure, located at the abutting part of the indexing arm (2) and the indexing wheel (3) and capable of restricting the rotation of the indexing wheel (3); And A second self-locking structure, for fixing the first end of the indexing arm (2).

2. The self-locking counting device according to claim 1, wherein The indexing arm (2) includes an indexing rod (21), the first self-locking structure includes a first locking protrusion (22) provided at the end of the indexing rod (21), a plurality of second locking protrusions (31) arranged around the indexing wheel (3), and a locking groove (32) provided between adjacent second locking protrusions (31), and the self-locking counting device has a counting state and a stationary state; In the counting state, the indexing wheel (3) rotates, and the first locking protrusion (22) abuts against the second locking protrusion (31) and the locking groove (32) alternately; In the stationary state, the indexing wheel (3) is stationary, and the first locking protrusion (22) abuts against the locking groove (32).

3. The self-locking counting device according to claim 2, wherein, The self-locking counting device also has a transition state, in which the indexing wheel (3) has a tendency to be stationary; The self-locking counting device further includes a guiding structure, in the transition state, the guiding structure is used to guide the first locking protrusion (22) into the locking groove (32), so that the self-locking counting device changes from the transition state to the stationary state; The guiding structure includes a first arc surface (221) provided on the end surface of the first locking protrusion (22) and a second arc surface (311) provided on the end surface of the second locking protrusion (31).

4. The self-locking counting device according to claim 3, wherein, The arc radius of the first arc surface (221) is 0.5 - 1.5 mm.

5. The self-locking counting device according to claim 3, wherein On one side and / or both sides of the indexing rod (21), there is a third arc surface (211), the bending direction of the third arc surface (211) is opposite to that of the first arc surface (221), and the arc radius of the third arc surface (211) is 3 - 4 mm.

6. The self-locking counting device according to claim 2, wherein, The indexing arm (2) further includes a mounting portion (23) provided at one end of the indexing arm (2), the indexing rod (21) is fixed on the mounting portion (23) or integrally formed therewith, the second self-locking structure includes a limiting block (4) and an abutting block (24) fixed on the mounting portion (23), the abutting block (24) abuts against the limiting block (4), and the position of the limiting block (4) is fixed.

7. The self-locking counting device according to claim 1, wherein The indexing arm (2) is detachable.

8. The self-locking counting device according to claim 6, wherein The end surface of the abutting block (24) abutting against the limiting block (4) is arc-shaped, and the arc radius of this end surface is 0.5 - 1.5 mm.

9. The self-locking counting device according to claim 6, wherein, There is an angle between the abutting block (24) and the indexing rod (21).

10. The self-locking counting device according to claim 6, wherein, The first counting unit (11) further includes a first driving gear (112), a main driving gear (113) and a first fixed shaft (114). The first driving gear (112) is coaxially mounted on the first fixed shaft (114) with the first digit wheel (111) and the indexing wheel (3) and rotates synchronously. The main driving gear (113) is meshed and connected with the first driving gear (112).

11. The self-locking counting device according to claim 10, wherein, The first counting unit (11) further includes a first carry gear (115). The first carry gear (115) is mounted on the first fixed shaft (114) and rotates synchronously with the first digit wheel (111). The first carry gear (115) is an incomplete gear; The counting assembly (1) further includes: A third counting unit (13) mounted on the first fixed shaft (114). The third counting unit (13) includes a third digit wheel (131) and a third driving gear (132) that rotate synchronously; One or more second counting units (12) mounted on the first fixed shaft (114). The second counting unit (12) includes a second digit wheel (121), a second driving gear (122) and a second carry gear (123) that rotate synchronously. The second carry gear (123) is an incomplete gear; A second fixed shaft (14); A plurality of transmission gears (15) mounted on the second fixed shaft (14). Each transmission gear (15) is meshed with a corresponding third driving gear (132), and the transmission gear (15) is also periodically meshed with the first carry gear (115) or the second carry gear (123).

12. The self-locking counting device according to claim 11, wherein, The mounting portion (23) is mounted on the second fixed shaft (14).

13. A pipette, characterized in that, Comprising the self-locking counting device according to any one of claims 1 to 12.

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