Volume adjusting structure of pipette

Abstract

The invention relates to the technical field of pipetting instruments, and provides a pipetting gun capacity adjusting structure which comprises a shell, a piston cylinder body, a piston, a driving rod, a button, a piston rod, an adjusting screw rod, a driving sliding sleeve, an adjusting rotary drum, an auxiliary rotary drum and a fine adjustment sleeve, the driving sliding sleeve is slidably connected into the adjusting rotary drum, and the driving rod is rotatably connected into the top of the adjusting rotary drum; the adjusting rotating cylinder is slidably connected into the auxiliary rotating cylinder in the axial direction, external threads are formed in the circumferential outer surface of the bottom of the adjusting screw rod, the fine adjustment sleeve is rotationally connected into the shell along the axis in an axial limiting mode, and internal threads are formed in the circumferential inner surface of the top of the fine adjustment sleeve. The bottom of the adjusting screw rod downwards extends into the top of the fine-tuning sleeve and is in threaded transmission connection with the fine-tuning sleeve; the adjusting screw rod capable of adjusting the lifting height is adopted as a stroke limiting piece of the piston rod, the capacity can be rapidly adjusted by rotating the adjusting rotary drum, the rotating speed is high, and the capacity adjusting efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of pipette technology, and more specifically, to a pipette volume adjustment structure. Background Technology

[0002] Pipettes are essential tools for sample collection and transfer in biological, chemical, and clinical laboratory analyses. They are widely used in medical laboratories, biotechnology laboratories, food laboratories, pharmaceutical and chemical laboratories, and environmental laboratories. In medical clinical laboratories, they are mainly used in the sample preparation stage to achieve precise liquid ratio transfer.

[0003] Traditional manual pipettes typically include a handheld unit, a housing, a button, and a piston rod assembly. The piston rod assembly includes a piston cylinder located at the bottom of the housing, a piston located inside the piston cylinder, a drive rod that moves vertically within the housing, a piston rod, and a piston return spring. The upper part of the piston rod is sleeved and fixed to the bottom of the drive rod, and the lower part of the piston rod is fixedly connected to the top of the piston. Liquid aspiration and dispensing are achieved by controlling the piston to rise and fall within the piston cylinder. In experiments, it is often necessary to transfer different volumes of liquid, which requires that the capacity of a manual pipette be able to accommodate different volumes of liquid. To solve the problem of adjustable capacity of manual pipettes, Chinese patent application number CN201680021276.5 discloses a capacity adjustment method for manual pipettes. It uses three stepped cylindrical parts to adjust the piston stroke length. The stroke length is adjusted by rotating the stepped cylindrical parts by a manual dial. However, this capacity adjustment structure requires the manual dial to be slowly turned by the fingers. Since the manual dial is relatively small, it is difficult to exert force with the fingers, and the rotation speed is relatively slow. The fingers need to turn the manual dial many times to complete one revolution, which greatly reduces the efficiency of capacity adjustment. Summary of the Invention

[0004] The purpose of this invention is to provide a pipette volume adjustment structure that addresses the shortcomings of existing technologies, enabling rapid adjustment of pipette volume, greatly improving the efficiency of volume adjustment, and enhancing pipetting accuracy.

[0005] The technical solution of the present invention is as follows: A pipette volume adjustment structure includes a housing, a piston cylinder, a piston disposed within the piston cylinder, a drive rod vertically movably disposed within the housing, a button sleeved on the top of the drive rod, and a piston rod. The upper part of the piston rod is sleeved and fixed to the bottom of the drive rod, and the lower part of the piston rod is fixedly connected to the top of the piston. The structure also includes a hollow cylindrical adjusting screw sleeved outside the drive rod, a drive sleeve sleeved and fixed to the top of the adjusting screw, an adjusting rotary cylinder sleeved outside the drive sleeve, an auxiliary rotary cylinder rotatably connected to the housing along the axial direction, and a hollow cylinder sleeved outside the piston rod. A cylindrical fine-tuning sleeve is axially slidably connected to an adjusting cylinder. A driving rod is axially restricted and connected to the top of the adjusting cylinder. The adjusting cylinder is axially slidably connected to an auxiliary cylinder. The bottom of the adjusting screw has an external thread on its circumferential outer surface. The fine-tuning sleeve is axially restricted and rotatably connected to the housing. The top of the fine-tuning sleeve has an internal thread on its circumferential inner surface. The bottom of the adjusting screw extends downward into the top of the fine-tuning sleeve and is threadedly connected to the fine-tuning sleeve. When the pipette is in the initial state or the aspiration is complete state, the top of the piston rod abuts against the bottom of the adjusting screw.

[0006] A further improvement to the above scheme is that a locking mechanism is provided between the fine-tuning sleeve and the housing to restrict the rotation of the fine-tuning sleeve. The locking mechanism includes a rotating retaining ring sleeved outside the fine-tuning sleeve, a locking retaining ring sleeved outside the fine-tuning sleeve, a retaining member located above the rotating retaining ring, an unlocking reset spring providing an upward pushing force to the rotating retaining ring, and a retaining reset spring providing a downward pushing force to the retaining member. The locking retaining ring is fixed inside the housing, and the rotating retaining ring is axially slidably connected to the outside of the fine-tuning sleeve in a rotationally restricted manner. The top of the locking retaining ring is formed with a first toothed surface along the circumferential direction, and the bottom of the rotating retaining ring is formed with a second toothed surface along the circumferential direction that matches the first toothed surface. When the locking mechanism is in the locked state, the retaining member pushes the rotating retaining ring downward under the action of the retaining reset spring, so that the second toothed surface of the rotating retaining ring engages and is fixed with the first toothed surface of the locking retaining ring.

[0007] A further improvement to the above solution is that the locking mechanism further includes a mounting base fixed inside the housing, a retainer movably disposed inside the mounting base, a vertically inclined push-up slope formed at the bottom of the mounting base, a push-up protrusion at the top of the retainer, the push-up protrusion pressing against the push-up slope, a retaining return spring disposed laterally between the retainer and the mounting base, and pushes the retainer so that the push-up protrusion presses against the push-up slope, and an adjustment socket is provided on the side of the housing facing away from the push-up slope, with the side of the retainer away from the retaining return spring close to the adjustment socket.

[0008] A further improvement to the above scheme is that the top of the unlocking and reset spring presses against the rotating wheel retaining ring, the bottom of the unlocking and reset spring presses against the fine-tuning sleeve, the outer surface of the fine-tuning sleeve is provided with a fine-tuning groove along the axial direction, and the inner surface of the rotating wheel retaining ring is formed with a fine-tuning guide post along the axial direction, and the fine-tuning guide post is slidably connected in the fine-tuning groove.

[0009] A further improvement to the above solution is that the outer surface of the fine-tuning sleeve is provided with an annular groove along the circumference, a limiting ring is fixed inside the housing, and an annular protrusion that mates with the annular groove is formed on the inner surface of the limiting ring along the circumference. The annular protrusion is slidably disposed in the annular groove.

[0010] A further improvement to the above scheme is that the inner surface of the adjusting cylinder is provided with a guide groove along the axial direction, the outer surface of the driving sleeve is formed with a driving guide post along the axial direction, and the driving guide post is slidably connected in the guide groove; the inner surface of the auxiliary cylinder is provided with an auxiliary groove along the axial direction, the outer surface of the adjusting cylinder is formed with an auxiliary guide post along the axial direction, and the auxiliary guide post is slidably connected in the auxiliary groove.

[0011] A further improvement to the above scheme is that the top of the adjusting drum is provided with a connecting hole along the axial direction, and an annular limiting groove is provided in the connecting hole. An annular limiting part is protruding on the outer circumferential surface of the drive rod. The drive rod is inserted and fixed in the connecting hole and the annular limiting part is embedded in the annular limiting groove.

[0012] A further improvement to the above scheme is that the top of the adjusting drum is provided with an adjusting locking device, which includes an adjusting knob sleeved on the outside of the drive rod. The button has a hollow structure, and the inner surface of the button is formed with an inwardly protruding first locking tooth surface along the circumferential direction. The adjusting knob is located below the button and is engaged with the top of the adjusting drum. The top of the adjusting knob is formed with an annular step protruding radially outward. The outer circumferential surface of the annular step is formed with a second locking tooth surface that mates with the first locking tooth surface. The annular step is located inside the button, and the first locking tooth surface is located directly below the second locking tooth surface.

[0013] A further improvement to the above solution is that a hollow connecting post protrudes downward at the center of the button shaft. The connecting post is slidably sleeved on the top of the drive rod. A retaining ring is provided on the outside of the connecting post. A retaining ring groove is formed in the inner cavity of the adjusting seat, and the connecting retaining ring is slidably disposed in the retaining ring groove. A limiting flange is formed inward at the bottom of the first locking tooth surface on the inner surface of the button, and the limiting flange extends to below the annular step.

[0014] A further improvement to the above solution is that a protective sleeve is fitted around the bottom of the adjusting knob, with the top of the protective sleeve extending upward into the button and the bottom of the protective sleeve fitted around the outside of the adjusting drum.

[0015] The beneficial effects of this invention are: This invention provides a pipette volume adjustment structure, including a housing, a piston cylinder, a piston, a drive rod, a button, a piston rod, an adjusting screw, a drive sleeve, an adjusting cylinder, an auxiliary cylinder, and a fine-tuning sleeve. The drive sleeve is axially slidably connected inside the adjusting cylinder. The drive rod is axially restricted and connected to the top of the adjusting cylinder. The adjusting cylinder is axially slidably connected inside the auxiliary cylinder. The bottom of the adjusting screw has an external thread on its circumferential outer surface. The fine-tuning sleeve is axially restricted and rotatably connected to the housing along its axis. The top of the fine-tuning sleeve has an internal thread on its circumferential inner surface. The bottom of the adjusting screw extends downward into the top of the fine-tuning sleeve and is threadedly connected to the fine-tuning sleeve. When the pipette is in its initial state or after aspiration, the top of the piston rod abuts against the bottom of the adjusting screw. When the adjusting cylinder is rotated, it drives the drive sleeve and the adjusting screw to rotate together. The adjusting screw, under the action of its threaded connection with the fine-tuning sleeve, simultaneously moves up and down, thereby adjusting the position of the piston rod and the highest point of the piston stroke, thus achieving the effect of adjusting the volume.

[0016] This invention uses an adjustable screw with adjustable lifting height as the stroke limiter of the piston rod. The volume can be quickly adjusted by rotating the adjusting cylinder, and the rotation speed is relatively fast, which greatly improves the efficiency of volume adjustment. This invention also uses a fine-tuning sleeve as an adjustment tool for correcting the volume. When the volume of the pipette is inaccurate during factory testing or after long-term use, the volume can be adjusted by rotating the fine-tuning sleeve to drive the adjusting screw to rise and fall, thereby correcting the accuracy of the pipette and improving the pipetting accuracy. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a schematic diagram of the pipette of the present invention; Figure 2 This is a cross-sectional view of the pipette of the present invention; Figure 3 This is an exploded view of the capacity adjustment structure of the present invention; Figure 4 for Figure 2 A magnified view of a section at point A in the middle; Figure 5 This is an exploded view of the locking mechanism of the present invention; Figure 6 This is a schematic diagram of the structure of the mounting base of the present invention; Figure 7 This is a schematic diagram of the structure of the adjusting drum of the present invention; Figure 8 This is a cross-sectional view of the adjusting locking device of the present invention; Figure 9 This is an exploded view of the adjusting locking device of the present invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1 to 9 As shown, this embodiment proposes a pipette volume adjustment structure, which includes a housing 1, a piston cylinder 21, a piston 22 disposed within the piston cylinder 21, a drive rod 24 vertically movably disposed within the housing 1, a button 26 sleeved on the top of the drive rod 24, and a piston rod 23. The upper part of the piston rod 23 is sleeved and fixed to the bottom of the drive rod 24, and the lower part of the piston rod 23 is fixedly connected to the top of the piston 22. It also includes a hollow cylindrical adjusting screw 31 sleeved outside the drive rod 24, a drive sleeve 32 sleeved and fixed to the top of the adjusting screw 31, an adjusting rotary cylinder 33 sleeved outside the drive sleeve 32, an auxiliary rotary cylinder 34 rotatably connected to the housing 1 along the axial direction, and a button 26 sleeved on the piston rod 24. The hollow cylindrical fine-tuning sleeve 35 outside the piston rod 23 is axially slidably connected to the adjusting cylinder 33 via the drive sliding sleeve 32. The drive rod 24 is axially restricted and connected to the top of the adjusting cylinder 33. The adjusting cylinder 33 is axially slidably connected to the auxiliary cylinder 34. The bottom of the adjusting screw 31 has an external thread on its circumferential outer surface. The fine-tuning sleeve 35 is axially restricted and rotatably connected to the housing 1 along its axis. The top of the fine-tuning sleeve 35 has an internal thread on its circumferential inner surface. The bottom of the adjusting screw 31 extends downward into the top of the fine-tuning sleeve 35 and is threadedly connected to the fine-tuning sleeve 35. When the pipette is in the initial state or the liquid aspiration is completed, the top of the piston rod 23 abuts against the bottom of the adjusting screw 31. A piston return spring is provided between the piston rod 23 and the fine-tuning sleeve 35. The piston return spring provides an upward reset force for the piston rod 23. When the pipette is in the initial state or the aspiration is complete state (i.e., when the button 26 is released), the piston return spring will push the piston rod 23 upward until the top of the piston rod 23 abuts against the bottom of the adjusting screw 31. When the adjusting drum 33 is rotated, the adjusting drum 33 drives the drive sleeve 32 and the adjusting screw 31 to rotate together. The adjusting screw 31, under the action of the threaded transmission connection with the fine-tuning sleeve 35, simultaneously performs a lifting and lowering action, thereby adjusting the position of the piston rod 23 and the piston 22 at the highest point of their stroke, thus achieving the effect of adjusting the volume.

[0021] The inner surface of the adjusting drum 33 is provided with a guide groove 331 along the axial direction, and the outer surface of the driving sleeve 32 is formed with a driving guide post 321 along the axial direction. The driving guide post 321 is slidably connected in the guide groove 331, so that the adjusting drum 33 and the driving sleeve 32 can rotate synchronously and slide relative to each other along the axial direction, making the adjustment more stable and smooth. The inner surface of the auxiliary drum 34 is provided with an auxiliary groove 341 along the axial direction, and the outer surface of the adjusting drum 33 is formed with an auxiliary guide post 332 along the axial direction. The auxiliary guide post 332 is slidably connected in the auxiliary groove 341, so that the adjusting drum 33 drives the auxiliary drum 34 to rotate synchronously and slide relative to each other along the axial direction, making the adjustment more stable and smooth.

[0022] The top of the adjusting drum 33 is provided with a connecting hole 333 along the axial direction. Multiple annular limiting grooves 334 are provided in the connecting hole 333. Multiple annular limiting parts 241 corresponding to the annular limiting grooves 334 are protruding from the outer surface of the drive rod 24. The drive rod 24 is inserted and fixed in the connecting hole 333 and the annular limiting parts 241 are embedded in the annular limiting grooves 334, so that the connection between the adjusting drum 33 and the drive rod 24 is more stable.

[0023] A damping structure can be provided between the auxiliary rotating drum 34 and the housing 1, allowing the auxiliary rotating drum 34 to rotate relative to the housing 1 only when the torque reaches a certain level. A counter 7 is installed inside the housing 1, and the bottom of the auxiliary rotating drum 34 rotatably drives the counter 7. This counter 7 is used to display the value of the capacity adjusted by the capacity adjustment mechanism. The counter 7 can be a three-digit counter 7, a four-digit counter 7, or other types of digital counter 7. This counter 7 is prior art, such as the counter 7 mentioned in Chinese patent CN111989160B.

[0024] The top of the adjusting drum 33 is provided with an adjusting locking device 6. The adjusting locking device 6 includes an adjusting knob 61 sleeved on the outside of the drive rod 24. The button 26 has a hollow structure. The inner surface of the button 26 is formed with an inwardly protruding first locking tooth surface 264 along the circumferential direction. The adjusting knob 61 is located below the button 26 and is engaged with the top of the adjusting drum 33. The top of the adjusting knob 61 is formed with an annular step 611 protruding radially outward. The outer circumferential surface of the annular step 611 is formed with a second locking tooth surface 612 that cooperates with the first locking tooth surface 264. The annular step 611 is located inside the button 26. The unlocked state of the adjusting locking device 6 is the normal state. When the adjusting locking device 6 is in the unlocked state, the first locking tooth surface 264 is located directly below the second locking tooth surface 612. At this time, rotating the button 26 will not drive the adjusting knob 61 to rotate, and the capacity cannot be adjusted. When it is necessary to adjust the capacity, simply lift the button 26 upwards, which will drive the first locking tooth surface 264 on the button 26 to move upwards and engage with the second locking tooth surface 612 of the adjusting knob 61, locking the button 26 and the adjusting knob 61 to form a locked state. At this time, rotating the button 26 will drive the adjusting knob 61 and the adjusting drum 33 to rotate together, thereby realizing the capacity adjustment. Pressing the button 26 downwards will drive the first locking tooth surface 264 on the button 26 to move downwards and disengage from the second locking tooth surface 612 of the adjusting knob 61. The button 26 and the adjusting knob 61 can rotate relative to each other to form an unlocked state. By adjusting the locking state of the locking device 6, button 26 can be transformed into a volume adjustment knob. Since button 26 is located on top of the pipette and its area and thickness are several times larger than existing manual rotary knobs, it can be operated with the entire palm of the hand, making it easier to apply force. Turning button 26 once by hand results in approximately one full rotation, significantly improving the efficiency of volume adjustment. Furthermore, lifting and pressing button 26 quickly switches between the locked and unlocked states of the locking device 6, providing quick and convenient operation while preventing accidental volume adjustment and improving operational accuracy.

[0025] A hollow connecting post 265 protrudes downwards from the center of button 26. The connecting post 265 slides on the top of the drive rod 24, guiding button 26 and allowing it to rotate and slide more smoothly and evenly relative to the drive rod 24. A snap-fit ​​ring 62 is provided on the outside of the connecting post 265. A snap-fit ​​groove 613 is formed in the inner cavity of the adjusting base 61. The connecting snap-fit ​​ring 62 slides within the snap-fit ​​groove 613, axially limiting its movement and preventing button 26 from disengaging. The snap-fit ​​ring 62 is a magnet. An attractive iron piece 64 is located at the top of the snap-fit ​​groove 613 within the adjusting base 61, designed to magnetically attract the snap-fit ​​ring 62. When button 26 is lifted upwards, the snap-fit ​​ring 62 adheres to the attractive iron piece 64, holding button 26 in the pulled-up position and preventing it from falling. A clicking sound also indicates that the button has been lifted to the correct position. A limiting flange 266 is formed inward on the inner surface of button 26 at the bottom of the first locking tooth surface 264. The limiting flange 266 extends to the bottom of the annular step 611 and limits the rising height of button 26.

[0026] A protective sleeve 63 is fitted around the bottom of the adjusting knob 61. The top of the protective sleeve 63 extends upward and fixes the button 26, while the bottom of the protective sleeve 63 is fitted around the adjusting cylinder 33. In this embodiment, the adjusting cylinder 33 has a support portion 335 protruding outward from its circumferential outer surface. The bottom of the protective sleeve 63 presses against the support portion 335. The protective sleeve 63 can enclose and protect both the adjusting knob 61 and the adjusting cylinder 33, preventing the adjustment knob 61 and the adjusting cylinder 33 from being touched by hand and causing changes in capacity, effectively preventing misoperation and improving operating accuracy.

[0027] Button 26 includes an upper cover 261, an annular lower cover 262 located below the upper cover 261, and a rotating ring 263. The rotating ring 263 is located between the upper cover 261 and the lower cover 262. The upper cover 261 and the lower cover 262 are respectively engaged and fixed with the rotating ring 263. A first locking tooth surface 264 is located on the lower cover 262, which facilitates processing and assembly. The outer surface of the rotating ring 263 has anti-slip stripes 2631 to facilitate rotating the button 26.

[0028] The bottom of the fine-tuning sleeve 35 extends downwards from the bottom of the housing 1, and the piston cylinder 21 is fixed to the bottom of the fine-tuning sleeve 35. When fine-tuning is required, the gun head can be removed and the fine-tuning sleeve 35 or the piston cylinder 21 can be rotated by hand for adjustment. This is convenient to operate and protects the fine-tuning sleeve 35 from accidental contact.

[0029] A locking mechanism 4 is provided between the fine-tuning sleeve 35 and the housing 1 to restrict the rotation of the fine-tuning sleeve 35. The locking mechanism 4 includes a rotating retaining ring 42 sleeved on the outside of the fine-tuning sleeve 35, a locking retaining ring 43 sleeved on the outside of the fine-tuning sleeve 35, a retaining member 44 located above the rotating retaining ring 42, an unlocking return spring 45 providing an upward pushing force to the rotating retaining ring 42, and a retaining return spring 46 providing a downward pushing force to the retaining member 44. The locking retaining ring 43 and the housing 1 are integrally formed. The rotating retaining ring 42 is axially slidably connected to the outside of the fine-tuning sleeve 35 in a rotationally restricted manner. The top of the locking retaining ring 43 has a first toothed surface 431 formed circumferentially, and the bottom of the rotating retaining ring 42 has a second toothed surface 421 formed circumferentially to match the first toothed surface 431. Both the first toothed surface 431 and the second toothed surface 421 are conical toothed surfaces, which have an automatic alignment and positioning function.

[0030] When the locking mechanism 4 is in the locked state, the retaining member 44 pushes the rotary retaining ring 42 downward under the action of the retaining return spring 46, so that the second tooth surface 421 of the rotary retaining ring 42 engages and fixes with the first tooth surface 431 of the locking retaining ring 43, thus locking and fixing the rotary retaining ring 42 onto the locking retaining ring 43, thereby locking and fixing the fine-tuning sleeve 35 so that it cannot rotate. When the retaining member 44 is pushed upward, the rotary retaining ring 42 will slide upward under the action of the unlocking return spring 45, so that the second tooth surface 421 disengages from the first tooth surface 431 of the locking retaining ring 43 and enters the unlocked state. At this time, the rotary retaining ring 42 and the fine-tuning sleeve 35 can be freely rotated to fine-tune the capacity. The locked state of the locking mechanism 4 is the normal state, and the fine-tuning sleeve 35 cannot rotate. By controlling the retaining member 44, it can be quickly switched to the unlocked state, which is quick and convenient to operate, prevents misoperation, and improves the accuracy of operation.

[0031] The locking mechanism 4 also includes a mounting base 41 fixed in the housing 1, and a retaining member 44 movably disposed in the mounting base 41. The bottom of the mounting base 41 is formed with an upwardly inclined pushing surface 411, and the top of the retaining member 44 is provided with a pushing protrusion 441. The pushing protrusion 441 presses against the pushing surface 411. The retaining return spring 46 is disposed laterally between the retaining member 44 and the mounting base 41, and pushes the retaining member 44 so that the pushing protrusion 441 presses against the pushing surface 411. Under the action of the pushing surface 411, the retaining member 44 generates a downward pressing force on the rotating ring 42. An adjustment socket 11 is provided on the side of the housing 1 facing away from the push-up slope 411. The retaining member 44 is located near the adjustment socket 11 on the side away from the retaining return spring 46. A cylindrical object with a diameter smaller than the socket is inserted into the socket and pushes the retaining member 44, causing the push-up protrusion 441 to disengage from the state of pressing against the push-up slope 411. At the same time, the retaining member 44 is pushed upward by the unlocking return spring 45 and the rotating retaining ring 42, thus entering the unlocked state. When the retaining member 44 is released, it slides downward along the push-up slope 411 under the action of the retaining return spring 46 and the push-up slope 411. At the same time, it pushes the rotating retaining ring 42 downward, causing the rotating retaining ring 42 to engage with the locking retaining ring 43 and lock it in place, thus entering the locked state. The unlocking operation of the locking mechanism 4 is convenient and quick, has a simple structure, does not take up space, and can prevent accidental operation.

[0032] The bottom of the mounting base 41 has multiple pushing slopes 411, and the top of the retainer 44 has multiple pushing protrusions 441 corresponding to the pushing slopes 411, making the movement of the retainer 44 relative to the mounting base 41 more stable and smooth. The outer circumferential surface of the rotary retainer 42 is marked with scale markings, and the surface of the housing 1 is provided with a transparent observation window 12 located at the position of the rotary retainer 42. The change of the scale when the rotary retainer 42 rotates can be observed through the transparent observation window 12, so as to accurately control the amount of adjustment.

[0033] The top of the unlocking and reset spring 45 presses against the rotating wheel retaining ring 42, and the bottom of the unlocking and reset spring 45 presses against the fine-tuning sleeve 35. The outer surface of the fine-tuning sleeve 35 has a fine-tuning groove 351 formed along the axial direction, and the inner surface of the rotating wheel retaining ring 42 has a fine-tuning guide post 422 formed along the axial direction. The fine-tuning guide post 422 is slidably connected in the fine-tuning groove 351, so that the rotating wheel retaining ring 42 can rotate with the fine-tuning sleeve 35 and slide axially relative to the fine-tuning sleeve 35.

[0034] The outer surface of the fine-tuning sleeve 35 is provided with an annular groove 352 along the circumferential direction. A limiting ring 5 is fixed inside the housing 1. An annular protrusion 51 that cooperates with the annular groove 352 is formed on the inner surface of the limiting ring 5 along the circumferential direction. The annular protrusion 51 is slidably disposed in the annular groove 352, so that the fine-tuning sleeve 35 can rotate relative to the limiting ring 5 but cannot move relative to the axial direction.

[0035] In use, taking 1 mL of liquid pipetting as an example, first lift button 26 of the pipette to lock the adjusting locking device 6. Rotate button 26 to rotate the adjusting base 61 and adjusting cylinder 33 together. Adjust the volume to 1 mL according to the counter 7. Then move the pipette to the aspiration area and press button 26 down to aspirate. At this time, the adjusting locking device 6 automatically unlocks. Releasing button 26 automatically aspirates the liquid. When the volume of aspirated liquid is found to be inconsistent with the volume displayed by counter 7, the error value is calculated. Insert a cylindrical object with a diameter smaller than the insertion hole into the insertion hole and push the retaining member 44 to unlock the locking mechanism 4. At the same time, rotate the fine-tuning sleeve 35 to rotate the rotating wheel retaining ring 42 by the angle corresponding to the error value, thus completing the volume error correction adjustment. Under normal conditions, the adjusting locking device is in the unlocked state while the locking mechanism 4 is in the locked state. At this time, the adjusting cylinder 33 and the fine-tuning sleeve 35 cannot rotate, and the volume cannot be adjusted or the volume error corrected.

[0036] This invention employs an adjustable screw 31 with adjustable height as the stroke limiter for the piston rod 23. Volume can be quickly adjusted by rotating the adjusting cylinder 33, and the relatively fast rotation speed greatly improves the efficiency of volume adjustment. This invention also uses a fine-tuning sleeve 35 as a volume correction tool. When volume errors occur during factory testing or after prolonged use, the volume can be adjusted by rotating the fine-tuning sleeve 35 to raise or lower the adjusting screw 31, thus correcting the accuracy and improving the pipetting precision of the pipette. This invention uses two adjustment systems—volume adjustment and volume correction—working together. The volume adjustment structure quickly adjusts the volume, while the volume correction structure corrects the volume accuracy, ensuring pipetting precision and greatly improving operational efficiency while maintaining pipetting accuracy.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pipette volume adjustment structure, comprising a housing (1), a piston cylinder (21), a piston (22) disposed within the piston cylinder (21), a drive rod (24) vertically movably disposed within the housing (1), a button (26) sleeved on the top of the drive rod (24), and a piston rod (23), wherein the upper part of the piston rod (23) is sleeved and fixed to the bottom of the drive rod (24), and the lower part of the piston rod (23) is fixedly connected to the top of the piston (22), characterized in that: It also includes a hollow cylindrical adjusting screw (31) sleeved outside the drive rod (24), a drive sleeve (32) sleeved and fixed to the top of the adjusting screw (31), an adjusting cylinder (33) sleeved outside the drive sleeve (32), an auxiliary cylinder (34) rotatably connected to the housing (1) along the axial direction, and a hollow cylindrical fine-tuning sleeve (35) sleeved outside the piston rod (23). The drive sleeve (32) is slidably connected to the adjusting cylinder (33) along the axial direction, the drive rod (24) is axially restricted and connected to the top of the adjusting cylinder (33), and the adjusting cylinder (33) is slidably connected to the auxiliary cylinder (34) along the axial direction. Inside the housing (1), the outer surface of the bottom of the adjusting screw (31) is provided with an external thread. The fine adjustment sleeve (35) is rotatably connected to the housing (1) along the axis in an axially restricted manner. A locking mechanism (4) is provided between the fine adjustment sleeve (35) and the housing (1) to restrict the rotation of the fine adjustment sleeve (35). The inner surface of the top of the fine adjustment sleeve (35) is provided with an internal thread. The bottom of the adjusting screw (31) extends downward into the top of the fine adjustment sleeve (35) and is threadedly connected to the fine adjustment sleeve (35). When the pipette is in the initial state or the liquid aspiration is completed, the top of the piston rod (23) abuts against the bottom of the adjusting screw (31).

2. The pipette volume adjustment structure according to claim 1, characterized in that, The locking mechanism (4) includes a rotary retaining ring (42) sleeved on the outside of the fine-tuning sleeve (35), a locking retaining ring (43) sleeved on the outside of the fine-tuning sleeve (35), a retaining member (44) located above the rotary retaining ring (42), an unlocking reset spring (45) providing an upward pushing force to the rotary retaining ring (42), and a retaining reset spring (46) providing a downward pushing force to the retaining member (44). The locking retaining ring (43) is fixed inside the housing (1), and the rotary retaining ring (42) slides axially in a rotationally restricted manner. Connected to the outside of the fine-tuning sleeve (35), the top of the locking ring (43) is formed with a first tooth surface (431) along the circumferential direction, and the bottom of the rotating ring (42) is formed with a second tooth surface (421) that matches the first tooth surface (431) along the circumferential direction; when the locking mechanism (4) is in the locked state, the retaining member (44) pushes the rotating ring (42) downward under the action of the retaining return spring (46), so that the second tooth surface (421) of the rotating ring (42) engages and is fixed with the first tooth surface (431) of the locking ring (43).

3. The pipette volume adjustment structure according to claim 2, characterized in that, The locking mechanism (4) also includes a mounting base (41) fixed in the housing (1), a retainer (44) is movably disposed in the mounting base (41), the bottom of the mounting base (41) is formed with an upward and downward inclined push surface (411), the top of the retainer (44) is provided with a push protrusion (441), the push protrusion (441) presses against the push surface (411), the retaining return spring (46) is disposed laterally between the retainer (44) and the mounting base (41), and pushes the retainer (44) to make the push protrusion (441) press against the push surface (411), the housing (1) is provided with an adjustment socket (11) on the side facing away from the push surface (411), and the side of the retainer (44) away from the retaining return spring (46) is close to the adjustment socket (11).

4. The pipette volume adjustment structure according to claim 2, characterized in that, The top of the unlocking and reset spring (45) presses against the rotating wheel retainer (42), and the bottom of the unlocking and reset spring (45) presses against the fine-tuning sleeve (35). The outer surface of the fine-tuning sleeve (35) is provided with a fine-tuning groove (351) along the axial direction. The inner surface of the rotating wheel retainer (42) is formed with a fine-tuning guide post (422) along the axial direction. The fine-tuning guide post (422) is slidably connected in the fine-tuning groove (351).

5. The pipette volume adjustment structure according to claim 2, characterized in that, The outer surface of the fine-tuning sleeve (35) is provided with an annular groove (352) along the circumferential direction. A limiting ring (5) is fixed inside the housing (1). An annular protrusion (51) that cooperates with the annular groove (352) is formed on the inner surface of the limiting ring (5) along the circumferential direction. The annular protrusion (51) is slidably disposed in the annular groove (352).

6. The pipette volume adjustment structure according to claim 1, characterized in that, The inner surface of the adjusting cylinder (33) is provided with a guide groove (331) along the axial direction, and the outer surface of the driving sleeve (32) is formed with a driving guide post (321) along the axial direction. The driving guide post (321) is slidably connected in the guide groove (331). The inner surface of the auxiliary cylinder (34) is provided with an auxiliary groove (341) along the axial direction, and the outer surface of the adjusting cylinder (33) is formed with an auxiliary guide post (332) along the axial direction. The auxiliary guide post (332) is slidably connected in the auxiliary groove (341).

7. The pipette volume adjustment structure according to claim 1, characterized in that, The top of the adjusting drum (33) is provided with a connecting hole (333) along the axial direction. An annular limiting groove (334) is provided in the connecting hole (333). An annular limiting part (241) is protruding on the outer circumferential surface of the drive rod (24). The drive rod (24) is inserted and fixed in the connecting hole (333) and the annular limiting part (241) is embedded in the annular limiting groove (334).

8. A pipette volume adjustment structure according to any one of claims 1-7, characterized in that, The top of the adjusting drum (33) is provided with an adjusting locking device (6). The adjusting locking device (6) includes an adjusting knob (61) sleeved on the outside of the drive rod (24). The button (26) is a hollow structure. The inner surface of the button (26) is formed with an inwardly protruding first locking tooth surface (264) along the circumferential direction. The adjusting knob (61) is located below the button (26) and is engaged with the top of the adjusting drum (33). The top of the adjusting knob (61) is formed with an annular step (611) protruding outward along the radial direction. The outer circumferential surface of the annular step (611) is formed with a second locking tooth surface (612) that cooperates with the first locking tooth surface (264) along the circumferential direction. The annular step (611) is located inside the button (26), and the first locking tooth surface (264) is located directly below the second locking tooth surface (612).

9. A pipette volume adjustment structure according to claim 8, characterized in that, The button (26) has a hollow connecting post (265) protruding downward at the center of the axis. The connecting post (265) is slidably sleeved on the top of the drive rod (24). The connecting post (265) has a snap ring (62) on its outside. The adjusting seat (61) has a snap ring groove (613) formed in its inner cavity. The connecting snap ring (62) is slidably set in the snap ring groove (613). The inner surface of the button (26) is formed with a limiting flange (266) at the bottom of the first locking tooth surface (264). The limiting flange (266) extends to the bottom of the annular step (611).

10. A pipette volume adjustment structure according to claim 8, characterized in that, The bottom of the adjusting knob (61) is fitted with a protective sleeve (63), the top of the protective sleeve (63) extends upward into the button (26), and the bottom of the protective sleeve (63) is fitted outside the adjusting drum (33).

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