A pipetting device for blood culture bottles

Abstract

This application discloses a pipetting device for blood culture bottles, belonging to the field of liquid transfer. It includes: a pipette, a receiving chamber; a piston block; a pusher connected to the piston block for driving the piston block to move upwards or downwards; the pipetting device for blood culture bottles further includes: a support portion fixedly installed in the receiving chamber; an elastic portion for forming a transmission between the support portion and the piston block, so that the piston block is subjected to a force close to the support portion; a pressure rod connected to the piston block and forming an integral part with the piston block; wherein the pressure rod is threadedly connected to the support portion, and the pressure rod is self-rotating, allowing its end to move upwards or downwards relative to the support portion; a rotating portion is formed on the pressure rod and fixedly connected to the pressure rod; the rotating portion is at least partially located outside the pipette. This provides a pipetting device for blood culture bottles capable of transferring a specified volume of liquid.

Description

Technical Field

[0001] This application relates to the field of liquid transfer, and more specifically, to a pipetting device for blood culture bottles. Background Technology

[0002] In the related technical field, the pipetting device for blood culture bottles refers to the device used to transfer liquid from the culture bottle to a nutrient culture medium for culture. Generally, a syringe is used to extract a specified volume of liquid, and then the syringe is moved to another culture bottle to push the liquid out. However, when using a syringe to extract liquid, it is necessary to observe the position of the liquid level and align the liquid level with the scale value on the syringe in order to extract the specified volume of liquid. This method can result in a large error due to the user's observation method or hand tremors during operation.

[0003] A pipetting device for blood culture bottles is provided, which can transfer a specified volume of liquid. Summary of the Invention

[0004] The summary section of this application is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0005] To address the technical problems mentioned in the background section, some embodiments of this application provide a pipetting device for blood culture bottles, comprising: a pipette with a receiving chamber for containing liquid; a piston block installed in the receiving chamber; a pusher connected to the piston block for driving the piston block to move upward or downward; the pipetting device for blood culture bottles further comprising: a support portion fixedly installed in the receiving chamber; an elastic portion for forming a transmission between the support portion and the piston block, so that the piston block is subjected to a force close to the support portion; a pressure rod connected to the piston block and forming an integral part thereof; wherein the pressure rod is threadedly connected to the support portion, and the pressure rod is self-rotating, allowing its end to move upward or downward relative to the support portion; a rotating portion is formed on the pressure rod and fixedly connected to the pressure rod; the rotating portion is at least partially located outside the pipette.

[0006] By moving the piston block up or down, the space below the piston block can be increased or decreased, thereby increasing or decreasing the amount of liquid in the receiving chamber. This allows the pipette to draw in large or small amounts of liquid depending on the application, making it more adaptable to different situations. Additionally, pressing the pusher moves the piston block downwards, expelling gas from the receiving chamber. The pipette can then be moved to a blood culture bottle filled with liquid. Releasing the pusher causes the piston block to move upwards under the action of the elastic part, drawing liquid upwards. Pressing the pusher again allows the liquid to be expelled, thus achieving the liquid transfer operation.

[0007] Furthermore, the pipette has a stop at one end near the rotating part; the stop is fixed to the pipette; the stop has multiple through holes; a control part is provided below the stop; the control part has multiple through slots; the through slots match the shape and position of the through holes; the control part is rotatably connected to the pipette so that the control part can rotate relative to the stop, so that the through holes match, partially match, or do not match the through slots.

[0008] Furthermore, the stop portion is provided with a first arc-shaped groove; the control portion is provided with a second arc-shaped groove; the first arc-shaped groove and the second arc-shaped groove at least partially match.

[0009] Furthermore, the elastic part includes: a connecting plate, which is fixedly connected to the pressure rod; a tension spring structure located between the connecting plate and the support part, with both ends of the tension spring structure fixed to the connecting plate and the support part respectively; a plurality of limiting parts are formed on the connecting plate, and a limiting plane is formed at the end of the limiting part away from the connecting plate; the limiting plane abuts against the lower end face of the control part to limit the upward movement of the piston block.

[0010] Furthermore, the support portion is provided with a plurality of clearance grooves, which are used to accommodate the limiting portion so that the limiting portion passes through the support portion.

[0011] Furthermore, the elastic part also includes: a buffer structure located between the pressure rod and the piston block, so that the pressure rod is connected to the piston block through the buffer structure; the buffer structure is used to make the pressure rod and the piston block form an elastic connection.

[0012] Furthermore, the buffer structure includes: a fixed block, in which an installation chamber is formed; a first retaining ring is formed on the inner wall of the installation chamber, and the first retaining ring is fixed to the inner wall of the installation chamber; one end of the pressure rod is inserted into the installation chamber and forms a second retaining ring, the projections of the first retaining ring and the second retaining ring on the upper end face of the piston block at least partially overlap; and a buffer spring is provided between the second retaining ring and the upper end face of the piston block.

[0013] Furthermore, a closed cap is formed at the end of the pipette away from the pusher; an outlet for drawing in and expelling liquid is formed on the closed cap; the receiving chamber is located between the piston block and the closed cap.

[0014] Furthermore, the inner wall of the sealing cap is threadedly connected to the outer wall of the pipette.

[0015] Furthermore, the pipette has a notch at the control section; the control section is provided with a control rod, which is fixedly connected to the control section and at least partially passes through the notch so that a portion of the control rod is located outside the pipette.

[0016] The beneficial effect of this application is that it provides a pipetting device for blood culture bottles that can transfer a specified volume of liquid. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application.

[0018] Furthermore, throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the elements are not necessarily drawn to scale.

[0019] In the attached diagram:

[0020] Figure 1 This is an overall schematic diagram based on an embodiment of this application;

[0021] Figure 2 This is a structural schematic diagram of a part of an embodiment, mainly showing the structure of the connecting plate and some surrounding parts;

[0022] Figure 3 This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the support part;

[0023] Figure 4 This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the stop and some surrounding parts;

[0024] Figure 5 This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the control lever and some surrounding parts;

[0025] Figure 6 This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the connecting frame and some surrounding parts;

[0026] Figure 7This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the protruding column and some surrounding parts;

[0027] Figure 8 This is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the connecting frame and the protruding column;

[0028] Figure 9 This is a structural schematic diagram of a part of the embodiment, mainly showing... Figure 1 The cross-sectional structure;

[0029] Figure 10 yes Figure 9 Enlarged view of part A;

[0030] Figure 11 This is a structural schematic diagram of a part of the embodiment, mainly showing... Figure 9 A structure observed from another perspective;

[0031] Figure 12 yes Figure 11 Enlarged view of part B;

[0032] Figure 13 yes Figure 11 Enlarged view of part C;

[0033] Figure 14 This is a structural schematic diagram as part of an embodiment, mainly showing a partial structure of the parts in the first chamber.

[0034] Figure label:

[0035] 1. Pipette; 2. Sealing cap; 3. Piston block; 4. Connecting plate; 5. Support part; 6. Tension spring structure; 7. Fixing block; 8. Pressure plate; 9. Pressure rod; 41. Limiting plane; 71. First retaining ring; 72. Second retaining ring; 73. Buffer spring; 81. First chamber; 82. Second chamber; 83. Through groove; 84. Sliding plate; 85. Connecting rod; 86. Pressing block; 87. Fixing plate; 88. First tension spring; 89. Mounting ring; 91. Connecting bracket; 92. Protruding column; 93. Rotary knob; 94. Fixing ring; 95. Stop; 96. Control part; 811. Force plate; 812. Mounting column; 813. Push block; 814. Locking block; 815. Mounting plate; 816. Second tension spring; 817. Locking groove; 961. Detailed Implementation

[0036] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0037] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0038] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0039] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0040] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] Reference Figure 1-14 ,

[0042] A pipetting device for blood culture bottles includes: a pipette 1 with a receiving chamber for containing liquid inside; a piston block 3 installed in the receiving chamber; a pusher connected to the piston block 3 for driving the piston block 3 to move upward or downward; the pipetting device for blood culture bottles further includes: a support portion 5 fixedly installed in the receiving chamber; an elastic portion for forming a transmission between the support portion 5 and the piston block 3, so that the piston block 3 is subjected to a force close to the support portion 5; a pressure rod 9 connected to the piston block 3 and forming an integral part with the piston block 3; wherein the pressure rod 9 is threadedly connected to the support portion 5, and the pressure rod 9 is self-rotating, allowing the end of the pressure rod 9 to move upward or downward relative to the support portion 5; a rotating portion is formed on the pressure rod 9 and fixedly connected to the pressure rod 9; the rotating portion is at least partially located outside the pipette 1. The end of the pipette 1 furthest from the pusher has a sealing cap 2; the sealing cap 2 has an outlet for drawing in and expelling liquid; the receiving chamber is located between the piston block 3 and the sealing cap 2. The inner wall of the sealing cap 2 is threaded to the outer wall of the pipette 1.

[0043] By moving the piston block 3 up or down, the space below the piston block 3 can be increased or decreased, thereby increasing or decreasing the amount of liquid in the receiving chamber. This allows the pipette 1 to draw in large or small amounts of liquid depending on the application, making it more adaptable to different situations. In addition, pressing the pusher moves the piston block 3 downward, expelling gas from the receiving chamber. Then, the pipette 1 is moved to a blood culture bottle filled with liquid. Releasing the pusher causes the piston block 3 to move upward under the action of the elastic part, drawing liquid upward. Pressing the pusher again allows the liquid to be expelled, thus achieving the operation of transferring liquid.

[0044] Furthermore, the pipette 1 has a stop 95 at one end near the rotating part; the stop 95 is fixed to the pipette 1; the stop 95 has multiple through holes; a control part 96 is provided below the stop 95; the control part 96 has multiple through grooves 83; the through grooves 83 match the shape and position of the through holes; the control part 96 is rotatably connected to the pipette 1 so that the control part 96 can rotate relative to the stop 95, so that the through holes match, partially match, or do not match the through grooves 83. The pipette 1 has a notch at the control part 96; the control part 96 has a control rod 961, the control rod 961 is fixedly connected to the control part 96 and at least partially passes through the notch so that part of the control rod 961 is located outside the pipette 1.

[0045] The stop 95 and control 96 are located near the rotating part, both situated above the piston block 3. The piston block 3 is sealed to the inner wall of the pipette 1. Moving the piston block 3 upwards compresses the air above it, causing it to escape outwards. The control 96 can rotate, and it has a through groove 83. The stop 95 has a through hole. The through groove 83 matches the through hole, meaning the projection of the through groove 83 onto the end face of the stop 95 completely overlaps with the through groove 83. At this point, air can escape normally. When the control 96 is rotated to partially match the through groove 83 with the through hole, this partial matching is the result of the through groove... The projection of 83 on the end face of the stop 95 partially overlaps with the through groove 83, which reduces the speed at which air is expelled outward, thus applying a downward force to the piston block 3. Since the piston block 3 is reset by the elastic element, the elastic force of the elastic element will cause the piston block 3 to move upward quickly. If the piston block 3 moves upward too quickly, the liquid may not be completely drawn in, or there may be air in the drawn-in liquid, which will lead to inaccurate liquid volume. By matching the through groove 83 with the through hole, the upward speed of the piston block 3 is reduced, allowing the piston block 3 to slowly draw the liquid into the receiving chamber.

[0046] Furthermore, the baffle 95 has a first arc-shaped groove; the control part 96 has a second arc-shaped groove; the first arc-shaped groove and the second arc-shaped groove at least partially match. Both the first arc-shaped groove and the second arc-shaped groove are narrow grooves. When the through groove 83 does not match the through hole, air can be discharged outward through the first arc-shaped groove and the second arc-shaped groove, thereby controlling the speed at which the piston block 3 draws liquid into the receiving chamber.

[0047] Further, the elastic part includes: a connecting plate 4, which is fixedly connected to the pressure rod 9; a tension spring structure 6, which is located between the connecting plate 4 and the support part 5, and both ends of the tension spring structure 6 are fixed to the connecting plate 4 and the support part 5 respectively; a plurality of limiting parts are formed on the connecting plate 4, and a limiting plane 41 is formed at the end of the limiting part away from the connecting plate 4; the limiting plane 41 abuts against the lower end face of the control part 96 to limit the upward movement of the piston block 3. A plurality of clearance grooves are provided on the support part 5, which are used to accommodate the limiting parts so that the limiting parts pass through the support part 5. The elastic part also includes: a buffer structure, which is located between the pressure rod 9 and the piston block 3 so that the pressure rod 9 is connected to the piston block 3 through the buffer structure; the buffer structure is used to make the pressure rod 9 and the piston block 3 form an elastic connection.

[0048] Furthermore, the buffer structure includes: a fixing block 7, in which an installation chamber is formed; a first retaining ring 71 is formed on the inner wall of the installation chamber, and the first retaining ring 71 is fixed to the inner wall of the installation chamber; one end of the pressure rod 9 is inserted into the installation chamber and forms a second retaining ring 72, and the projections of the first retaining ring 71 and the second retaining ring 72 on the upper end face of the piston block 3 at least partially overlap; a buffer spring 73 is provided between the second retaining ring 72 and the upper end face of the piston block 3.

[0049] In other embodiments, the rotating part includes: a fixing ring 94, which is fixedly connected to the inner wall of the pipette 1; a connecting frame 91 is provided below the fixing ring 94, which is connected to the pressure rod 9; a plurality of protruding posts 92 are formed on the connecting frame 91, and a rotating button 93 is provided on the protruding posts 92; a plurality of slots are provided on the rotating button 93, and the protruding posts 92 are inserted into the slots to make the rotating button 93 and the connecting frame 91 rotate synchronously, thereby making the rotating button 93 and the pressure rod 9 rotate synchronously; a plurality of vertical grooves are provided on the outer circular surface of the rotating button 93, which are used to cooperate with the finger to increase the friction between the finger and the rotating button 93, so that the rotating button 93 can be twisted and rotated more easily; the middle part of the connecting frame 91 is hollow, so that the connecting frame 91 will not block the through groove 83, the through hole, the first arc groove and the second arc groove.

[0050] In other embodiments, the pushing member is a pressure plate 8, which has a first chamber 81 and a second chamber 82. The pressure plate 8 also has a through groove 83 for connecting the first chamber 81 and the second chamber 82. A fixing plate 87 is provided in the second chamber 82, and the fixing plate 87 is fixedly connected to the pressure plate 8. A connecting rod 85 is slidably installed in the fixing plate 87, and the connecting rod 85 and the fixing plate 87 can slide relative to each other. A sliding plate 84 is provided below the connecting rod 85, and the sliding plate 84 abuts against the inner wall of the second chamber 82. A sliding connection is used, with the sliding plate 84 sealing the inner wall of the second chamber 82. An installation ring 89 is installed in the second chamber 82, threadedly connected to the inner wall of the second chamber 82. The installation ring 89 can be rotated and screwed in to fix it to the pressure plate 8. A groove is provided in the middle of the installation ring 89, large enough to accommodate a thumb. A pressing block 86 is installed in the groove and fixedly connected to the connecting rod 85. A first tension spring 88 is provided between the sliding plate 84 and the fixed plate 87. The first tension spring 88 is used to apply an upward force to the sliding plate 84. In actual use, pressing down with the thumb can press the edge of the plate 8 to move it downward, or pressing the middle of the plate 8 to press the pressing block 86 downward. Afterward, the first tension spring 88 is used to reset the pressing block 86 after it has been pressed down. The sliding plate 84 and the inner wall of the second chamber 82 form an oil cavity, which is filled with hydraulic oil. The mounting plate 815 is installed in the first chamber 81, and the mounting plate 815 is fixed to the inner wall of the first chamber 81. A mounting post 812 is inserted through the center of the mounting plate 815. The mounting post 812 is slidably connected to the mounting plate 815. One end of the mounting post 812 is fixedly mounted with a force-bearing plate 811, and the other end of the mounting post 812 is fixedly mounted with a push block 813. A locking block 814 is formed on the push block 813. A second tension spring 816 is provided between the push block 813 and the mounting plate 815. A slot 817 is provided on the inner wall of the rotary knob 93. The slot 817 is used to cooperate with the locking block 814 so that the slot 817 locks the locking block 814 in place.

[0051] Operating principle:

[0052] When in use, hold the pipette 1 with your hand, then place your thumb on the upper end of the pressure plate 8 and press the edge of the pressure plate 8 with your thumb. This will cause the pressure plate 8 to move downward. The pressure plate 8 will drive the pressure rod 9 to move downward, and the pressure rod 9 will drive the connecting plate 4 to move downward. The connecting plate 4 and the support part 5 will move away from each other, which will stretch the tension spring structure 6. The connecting plate 4 will be subjected to the tension force from the tension spring structure 6. The tension force on the connecting plate 4 is so that when the thumb leaves the pressure plate 8 and no longer presses the pressure plate 8, the tension spring structure 6 can drive the pressure rod 9 to return to its original position through the connecting plate 4.

[0053] When the pressure rod 9 moves downward, it drives the second retaining ring 72 to move downward. The second retaining ring 72 drives the piston block 3 to move downward through the buffer spring 73. When the pressure rod 9 returns to its original position, it drives the second retaining ring 72 to move upward. The second retaining ring 72 drives the fixed block 7 to move upward through the first retaining ring 71. The fixed block 7 is fixedly connected to the piston block 3, thereby driving the piston block 3 to return to its original position.

[0054] Move pipette 1 into the blood culture bottle, then release the pressure plate 8 with your thumb. The piston block 3 will return to its original position, thereby drawing the liquid in the blood culture bottle into the receiving chamber.

[0055] When it is necessary to adjust the volume of the inhaled liquid:

[0056] Hold the rotary knob 93 in your hand and rotate it. Rotating the rotary knob 93 will cause the protruding column 92 to rotate, which in turn causes the connecting frame 91 to rotate. The connecting frame 91 is connected to the pressure rod 9. Through the connection of the sliding key and the sliding groove, the connecting frame 91 and the pressure rod 9 can slide relative to each other along the axial direction of the pressure rod 9, but the pressure rod 9 and the connecting frame 91 cannot rotate relative to each other. Thus, the connecting frame 91 drives the pressure rod 9 to rotate. Because the pressure rod 9 is threadedly connected to the support part 5, the pressure rod 9 and the support part 5 will move axially. This allows the pressure rod 9 to be adjusted to move closer to or away from the sealing cover 2, thereby causing the piston block 3 to move closer to or away from the sealing cover 2, which in turn increases or decreases the volume of the receiving chamber.

[0057] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A pipetting device for blood culture bottle, comprising: a pipette, a containing chamber for containing liquid is formed inside the pipette; a piston block, installed in the containing chamber; a pushing member, connected to the piston block, for driving the piston block to move up or down; characterized in that: the pipetting device for blood culture bottle further comprises: a support part, fixedly installed in the containing chamber; a resilient part, for forming a transmission between the support part and the piston block, so that the piston block is subjected to a force close to the support part; a pressure rod, connected to the piston block and integrated with the piston block; wherein the pressure rod is threadedly connected with the support part, and the pressure rod can move up or down relative to the support part; a rotating part is formed on the pressure rod, and the rotating part is fixedly connected with the pressure rod; the rotating part is at least partially located outside the pipette; the rotating part comprises a fixed ring, which is fixedly connected with the inner wall of the pipette; a connecting frame is arranged below the fixed ring, and the connecting frame is connected with the pressure rod; a plurality of protruding columns are formed on the connecting frame; a rotating knob is arranged on the protruding columns; a plurality of insertion slots are formed on the rotating knob; the protruding columns are inserted into the insertion slots, so that the rotating knob and the connecting frame rotate synchronously, and then the rotating knob and the pressure rod rotate synchronously; a plurality of vertical slots are formed on the outer cylindrical surface of the rotating knob, which are used for cooperating with fingers to increase the friction between the fingers and the rotating knob, so that the rotating knob can be better twisted and rotated.

2. The pipetting device for blood culture bottle according to claim 1, characterized in that: an end of the pipette close to the rotating part is provided with a blocking part; the blocking part is fixedly connected with the pipette; a plurality of through holes are formed on the blocking part; a control part is arranged below the blocking part; a plurality of through slots are formed on the control part; the shapes and positions of the through slots and the through holes are matched; the control part is rotationally connected with the pipette, so that the control part can rotate relative to the blocking part, so that the through holes and the through slots are matched, partially matched or not matched.

3. The pipetting device for blood culture bottle according to claim 2, characterized in that: a first arc-shaped slot is formed on the blocking part; a second arc-shaped slot is formed on the control part; the first arc-shaped slot and the second arc-shaped slot are at least partially matched.

4. The pipetting device for blood culture bottle according to claim 2, characterized in that: the resilient part comprises: a connecting plate, which is fixedly connected with the pressure rod; a tension spring structure, which is located between the connecting plate and the support part, and the two ends of the tension spring structure are fixedly connected with the connecting plate and the support part, respectively; a plurality of limiting parts are formed on the connecting plate; the end of the limiting part away from the connecting plate forms a limiting plane; the limiting plane abuts against the lower end surface of the control part, so as to limit the upward movement of the piston block.

5. The pipetting device for blood culture bottle according to claim 4, characterized in that: a plurality of avoidance slots are formed on the support part, which are used for containing the limiting parts so that the limiting parts pass through the support part.

6. The pipette device for blood culture bottle according to claim 5, wherein: the elastic part further comprises: a buffer structure between the pressure rod and the piston block, so that the pressure rod is connected to the piston block through the buffer structure; the buffer structure is used to make the pressure rod and the piston block elastically connected.

7. The pipette device for blood culture bottle according to claim 6, wherein: the buffer structure comprises: a fixing block with an installation cavity; a first clasp is formed on the inner wall of the installation cavity, and the first clasp is fixed to the inner wall of the installation cavity; one end of the pressure rod is inserted into the installation cavity and forms a second clasp, and the first clasp and the second clasp at least partially overlap on the projection of the upper end surface of the piston block; a buffer spring is arranged between the second clasp and the upper end surface of the piston block.

8. The pipette device for blood culture bottle according to claim 1, wherein: one end of the pipette tube away from the pusher is formed with a closure cap; the closure cap is formed with an outlet for sucking and discharging liquid; the accommodation cavity is located between the piston block and the closure cap.

9. The pipette device for blood culture bottle according to claim 8, wherein: the inner wall of the closure cap is threadedly connected with the outer wall of the pipette tube.

10. The pipette device for blood culture bottle according to claim 7, wherein: the pipette tube is provided with a notch at the control part; the control part is provided with a control rod, and the control rod is fixedly connected with the control part and at least partially passes through the notch so that part of the control rod is located outside the pipette tube.

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