Pipette with adjustable pipetting volume and locking system

Abstract

The present invention relates to a pipette having a housing for housing a displacement device, the displacement device having a displacement chamber and a movable limiting element that limits the pipetting stroke of the pipette. The pipette includes an operating element for performing a pipetting process by moving the limiting element within the housing to set the pipetting volume of the pipette, the operating element being effectively connected to a plunger that can move within the displacement chamber of the displacement device, a counter for displaying the set pipetting volume, and a blocking mechanism for blocking and / or unblocking the volume setting made by the operating element. In a first position, the blocking slide allows adjustment of the pipetting volume, and in a second position, the blocking mechanism includes a block slide effectively connected to the locking ring and the counter connected to the locking ring, so as to block the rotation of the locking ring and the counter connected to the locking ring.

Description

Technical Field

[0001] The present invention relates to a pipette provided with a locking system for locking an adjustable pipetting volume and a set pipetting volume, according to the preamble of an independent claim.

Background Art

[0002] Pipettes are used for the controlled aspiration and discharge of liquids, particularly in laboratories. For this purpose, a pipette tip having an upper opening is fixed onto the seat of the pipette. The seat is preferably formed as a conical or cylindrical projection on the housing of the pipette. Through the lower opening, the pipette tip can aspirate and discharge liquid. An air cushion pipette comprises a displacement device for air connected to the pipette tip via a bore in the seat. This displacement device displaces the air cushion such that liquid is aspirated into the pipette tip and then discharged therefrom. For this purpose, the displacement device has a displacement chamber provided with a movable limiting member. The displacement device is usually a cylinder with a piston movable therein.

[0003] After use, the pipette tip is released from the seat and replaced with a new pipette tip. This prevents contamination in subsequent discharge operations. Most pipettes have an ejection mechanism for ejecting the pipette tip, allowing the tip to be ejected by push button operation without touching the tip. Disposable pipette tips for single use are made of plastic and are available at low cost.

[0004] The movable limiting section is connected to a drive mechanism that functions to move the piston within the cylinder. The drive mechanism has a plunger rod that is displaceable together with a stop element between an upper stop section and a lower stop section. At the start of air suction into the displacement chamber, the stop element is at the lower stop section. At the start of air discharge from the cylinder, the stop element abuts against the lower stop section. The volume of liquid taken in or discharged depends on the stroke of the movable limiting section, and therefore the stroke of the plunger rod.

[0005] In principle, systems for blocking the adjustment of a set pipetting volume, also known as "volume locks," are known from the prior art. Volume lock systems already exist that lock the counter mechanism and / or volume adjustment part by a form-fit connection between a return element and the adjustment mechanism. Furthermore, volume lock systems that establish the volume lock by a friction clutch are known from the prior art. However, the drawbacks here are that a relatively large force must be applied to engage the volume lock, the friction clutch tends to disengage too easily, and therefore does not enable functionally reliable locking of the set pipetting volume.

[0006] Furthermore, volume locking systems are known that require pressing an operating element throughout the entire volume setting process to keep the volume setting unlocked. This modification offers a high level of safety against unintentional adjustments to the set pipetting volume, but requires the use of both hands on the pipette to simultaneously press down the unlocking element and set the volume.

[0007] Furthermore, other volume locking systems can be unlocked by pulling the operating button upwards to the stopper position. During pipetting, this stopper is released, and the volume setting is locked again. This system also requires two-handed operation, holding the pipette with one hand and pulling up the operating button with the other. In addition, there are pipettes where turning the operating button to set the pipetting volume can inadvertently activate the volume lock. Moreover, according to user feedback, it is not intuitive that the operating button also serves to unlock the volume setting.

[0008] From Patent Document 1, an air cushion pipette is known that has an adjustable pipetting volume and a locking element for locking the set pipetting volume. This pipette has a rod-shaped housing, a seat at the lower end of the housing for detachably holding a pipette tip, and a displacement device having a displacement chamber and a movable limiting part inside it. This pipette further has a drive mechanism for moving the movable limiting part of the displacement device and a locking body that can lock the drive mechanism against undesirable adjustment of the set pipetting volume.

[0009] Patent Document 2 discloses a device for locking a volume adjustment screw for a pipetting system. The device for locking a volume adjustment screw for a pipetting system comprises, on the one hand, a meshing clutch system for holding the position of the volume adjustment screw, and this pipetting system, - A first gear having a first tooth, - A second gear having second teeth, wherein the first gear is a locking gear intended to be non-rotatable relative to the fixed part of the pipetting system, and the second gear is intended to be rotatably fixed relative to an adjustment screw, and vice versa. - Elastic return means that can return the first gear and the second gear toward each other so that the first tooth engages with the second tooth, Furthermore, a system for controlling a meshing clutch holding system, wherein the control system is - A position selector designed to rotate around the longitudinal central axis of the pipetting system between three positions: a free adjustment position, a fine adjustment position, and a locked position. - A control member connected to a position selector by a rotatable fixing, which interacts with the lock gear of the meshing clutch system, A system that includes, As a result, a) When the selector is in the free adjustment position, the control member axially separates the lock gear from the other gears of the meshing clutch system by resisting the force of the elastic return means, so that the first and second teeth do not engage. b) When the selector is in the fine adjustment position, the control member allows the lock gear to move away from it, and then, in the event of a tooth-to-tooth transition caused by the rotation of another gear, the lock gear moves axially closer to the other gear. c) When the selector is in the locked position, the control member locks the lock gear axially to prevent the first and second teeth from disengaging. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] European Patent Application Publication No. 2659978 [Patent Document 2] European Patent No. 3749456 [Overview of the Initiative]

[0011] The present invention aims to overcome the shortcomings known from the prior art and propose an operating concept for a pipette that enables simple and intuitive locking of the volume adjustment mechanism with low operating force, while reliably protecting the pipette user from undesirable adjustments to the set pipetting volume.

[0012] This objective is achieved by a pipette equipped with a housing for a displacement device, which comprises a displacement chamber and a movable limiting section for setting the pipetting stroke of the pipette. The pipette further has an operating element for setting the pipetting volume of the pipette by moving the limiting section within the housing and for performing the pipetting operation. The operating element is operably connected to a piston movable within the displacement chamber of the displacement device. In addition, the pipette includes a counter for displaying the set pipetting volume and a locking mechanism for locking and / or unlocking the volume setting via the operating element.

[0013] According to the present invention, the locking mechanism is provided to include a lock slide that interacts with a lock ring that can be connected to a counter, such that the lock ring in a first position allows adjustment of the pipetting volume, and the lock ring in a second position locks the rotation of the lock ring and the counter that can be connected to the lock ring. By locking the counter by fixing the lock ring, which is at least indirectly connected to the counter, the volume adjustment part can be effectively locked to protect the pipette from unintentional adjustment of the pipetting volume. In this way, the user can easily transition the pipette from a locked state to an unlocked state, preventing accidental changes in the pipetting volume.

[0014] The additional features described in the dependent claims enable advantageous embodiments and improvements of the pipette specified in the independent claim.

[0015] In an advantageous embodiment of the pipette, the locking mechanism is provided to include a blocking element (50) that prevents the rotation of the counter wheel of the counter when the locking mechanism is in the locked position. The blocking element can fix the locking ring in place in a simple manner, thereby preventing the rotation of the counter wheel of the counter and thus the adjustment of the pipetting volume. In particular, a shape-fit connection is established between the blocking element and the locking ring to prevent the rotation of the counter wheel of the counter.

[0016] According to an advantageous embodiment of the present invention, a first stop contour (Anschlagkontur) and a second stop contour are formed on the locking ring, and in the locked position of the locking mechanism, the locking slide abuts against the first stop contour, and in the unlocked position, it abuts against the second stop contour of the locking ring. As a result, the user can be given both visual and tactile feedback indicating whether the locking slide is in the unlocked or locked position. This particularly provides user-friendly locking or unlocking of the pipette volume adjustment section.

[0017] Preferably, the block element has a bearing element and at least one arm (preferably two arms extending from the bearing element), and the block element is rotatably mounted on the bearing element. This allows the block element to engage with the lock ring in a simple manner, and the locking of the lock ring, thereby preventing volume adjustment, is achieved through the interaction of the arms with this other element, either by the arms directly engaging with the lock ring and locking it, or by being held by another element.

[0018] Particularly preferred is that an engagement lug (Rastnocken) is formed on the arm of the block element, and this engagement lug engages with the cam contour on one of the counter wheels of the counter. Such an engagement lug can form a simple shape-fit connection between the arm of the block element and the lock ring. This allows the counter to be locked, ensuring that unintended adjustment of the pipetting volume is prevented.

[0019] In the advantageous further development of the pipette, a catch contour is provided that is formed on the first stop contour of the locking ring, and that the catch contour secures the engagement lug and prevents the engagement lug from lifting off the cam contour on one of the counter wheels of the counter. This prevents the engagement lug on the arm of the locking element from lifting off the cam contour on the counter wheel. Thus, even when greater force is applied, further rotation of the counter wheel is reliably prevented, and unintended volume changes of the pipetting volume are prevented.

[0020] Particularly preferably, a recess is formed on the catch contour, and within the recess, an engagement lug is at least partially housed in the locked position of the lock slide of the locking mechanism. This creates a secure engagement that holds the engagement lug substantially without play, thus ensuring secure engagement of the engagement lug in the cam contour of the counter wheel of the counter. This prevents unintended disengagement of the lock.

[0021] According to an advantageous embodiment of the pipette, it is provided that the catch contour prevents radially outward movement of the engagement lug, such that the engagement contour on the radially inwardly facing surface of the engagement lug is pressed into the cam contour on one of the counter wheels. In this way, a form-fitting locking connection is established between the engagement contour on the engagement lug and the cam contour on the counter wheel, which locks the adjustment of the counter and thus the pipetting volume. By blocking movement of the arm of the blocking element through catching the engagement lug, lifting of the arm of the blocking element and associated unlocking can be prevented.

[0022] In an advantageous embodiment of the pipette, it is provided that the blocking element is biased by a pressing element, in particular a spring, such that the arm of the blocking element is pressed against one of the counter wheels of the counter. In this case, the arm of the blocking element having the engagement lug is pressed against the cam contour of the counter by the pressing element. This means that in the unlocked state of the locking mechanism, simple adjustment of the pipetting volume is possible when the biasing force is overcome, and ensures that when locking is desired, the engagement lug on the arm and the arm of the blocking element can be fixed in a simple manner onto the cam contour of the counter wheel, thereby locking the volume adjustment unit.

[0023] In an advantageous embodiment of the present invention, in the unlocked position of the locking slide, radially outward movement of the engagement lug is enabled, allowing adjustment of the pipetting volume and associated rotation of the counter wheel of the counter. In the unlocked state of the locking slide, since the engagement lug is freely movable radially outward, the engagement lug can lift off the cam contour, and the counter wheel can rotate until the engagement lug engages into the next recess of the cam contour of the counter wheel, thereby adjusting the pipetting volume by one increment. Further rotation allows the engagement lug to engage with the counter wheel in discontinuous steps of one increment each, thereby enabling corresponding detenting of the engagement lug in the counter.

[0024] According to an advantageous embodiment of the pipette, it is provided that a counter wheel of a counter engages with a transmission gear of a volume adjusting unit. The pipetting volume is typically set by an operating button or an adjusting wheel surrounding the operating button, and the adjusting wheel is at least indirectly connected to the counter. The transmission gear ensures that adjustment of the pipetting volume is also locked when the counter is locked. As a result, locking and unlocking of volume adjustment can be achieved in a simple manner by means of a lock ring connected to the counter.

[0025] In an advantageous embodiment of the pipette, it is provided that a contour extending radially inward from the locking slide engages by form fit in a recess between a first stop contour and a second stop contour on the lock ring. This makes it possible to establish a form-fit connection between the locking slide and the lock ring of the locking mechanism in a structurally simple manner.

[0026] According to an advantageous embodiment of the pipette, it is provided that the locking slide of the locking mechanism is oriented perpendicular to the longitudinal axis of the pipette. This makes it possible to arrange the locking slide in a manner that is particularly user-friendly, and makes it easy for a user to lock or unlock the volume adjusting unit of the pipette.

[0027] For operating the pipette, advantageously, it is provided that a finger hook is formed on the housing, and the locking slide of the locking mechanism is arranged on a side of the housing opposite the finger hook. This enables particularly simple and comfortable operation, especially operation of the pipette with one hand. Specifically, the pipette can be held by the finger hook while the finger of the same hand moves the locking mechanism from the locked position to the unlocked position, and the pipetting volume is then set by rotating the operating button.

[0028] An advantageous embodiment of the present invention provides that the locking ring is positioned coaxially with the counter wheel of the counter on the counter axis. This facilitates rotating the locking ring relative to the counter wheel of the counter in order to transition the locking mechanism from an unlocked state to a locked state by rotating the locking ring.

[0029] The various embodiments of the invention described in this application can be combined to their advantage unless otherwise specified in the individual cases. [Brief explanation of the drawing]

[0030] The present invention is described below with reference to the accompanying drawings in exemplary embodiments. Identical components or components having the same function are identified by the same reference numerals in different drawings.

[0031] [Figure 1] This is a cross-sectional view of a pipette according to the present invention, which includes an adjustable pipetting volume and a locking system for temporarily and reversibly locking the volume setting of the pipette. [Figure 2] A preferred embodiment of such a pipette counter mechanism is that it includes a locking mechanism for locking the volume adjustment section of the pipette in a first switching position. [Figure 3] Another preferred embodiment of such a pipette counter mechanism is that it includes a locking mechanism for locking the volume adjustment section of the pipette in a second switching position. [Figure 4] This is a cross-sectional view of the pipette through the locking surface, where the volume adjustment section is locked in the locked position of the locking mechanism. [Figure 5] This is a cross-sectional view of a pipette with a movable volume adjustment section, passing through the locking surface, in the unlocked position of the locking mechanism. [Modes for carrying out the invention]

[0032] Figure 1 shows a cross-sectional view of the pipette 10 of the present invention. The pipette 10 has a pipette upper part 21 and a lower part (not shown in Figure 1) that can be attached to the pipette upper part 21. The pipette upper part 21 comprises a housing 20, and an operating element 12, preferably an operating button 14, protrudes through an opening in the housing 20 at the front of the housing 20, facing away from the pipette lower part. The operating element 12 has two functions. Firstly, the operating element 12 is used to set the pipetting volume, i.e., the amount of liquid drawn up by the pipette 10 and then dispensed during a pipetting operation. The pipetting volume is set by rotating the operating element 12, where rotating the operating element 12 in one direction increases the set pipetting volume, and rotating it in the opposite direction decreases it. The adjustable pipetting volume is determined by design and lies between the minimum pipetting volume and the maximum pipetting volume. Secondly, the operating element 12 functions to aspirate and then dispense liquid during pipetting, thereby causing the operating button 14 of the operating element 12 to move axially along the central axis of the pipette. Furthermore, a finger hook 16 is formed in the housing 20 to facilitate holding the pipette 10. Also located in the housing 20, preferably on the opposite side of the finger hook 16, is an ejector 18 for dropping the used pipette tip from the holder at the bottom of the pipette after pipetting. For this purpose, the ejector 18 is operably connected to an ejection linkage 19, which initiates the ejection of the pipette tip by pressing down on the end face of the pipette tip. Multiple functions, in particular volume adjustment, liquid volume intake and dispensing, and / or pipette tip ejection, can also be integrated into a single operating button 14, thereby allowing for easy and comfortable operation with only a single operating button 14. Alternatively, the function may be divided into multiple components of the operating element 12, and in particular, in addition to the operating button 14, a separate ejector 18 for ejecting used pipette tips may be provided.Furthermore, the operating element 12 may also include an operating button 14 for aspirating and dispensing liquid, and an element moved by the operating button 14 for setting the pipetting volume, in particular a rotating wheel for setting the pipetting volume.

[0033] The housing 20 includes a displacement device comprising a displacement chamber 24 and a movable limiting section 26 for limiting the pipetting stroke. The operating element 12 is configured to set the pipetting volume of the pipette 10 and perform a pipetting operation by moving the limiting section 26 within the housing 20. The operating element 12 is connected via a plunger rod 22 to a piston (not shown in Figure 1) that is movable within the displacement chamber 24 of the displacement device. The pipette 10 further includes a counter 30 for displaying the set pipetting volume and a locking mechanism 40 for locking and / or unlocking the volume setting via the operating element 12.

[0034] In this embodiment, the counter 30 comprises a first counter wheel (Zaehlrad) 32, a second counter wheel 34, a third counter wheel 36, and a fourth counter wheel 38. However, embodiments with fewer or more counter wheels are also possible.

[0035] The locking mechanism 40 includes a lock slide 42 for locking or unlocking the locking mechanism 40. The locking mechanism 40 further includes a lock ring 44, and the lock slide 42 engages with the lock ring 44 to move the volume adjustment section 60 of the pipette 10 from a locked state to an unlocked state, or from an unlocked state to a locked state.

[0036] A transparent viewing window is provided in the housing 20 so that the counter 30 can be viewed from the outside and the set pipetting volume can be read. A movable limiting part 26 for the plunger rod 22 is provided inside the housing 20, and the stroke of the piston is limited when the shoulder of the plunger rod 22 comes into contact with the movable limiting part 26. The pipetting volume is adjusted by displacing the limiting part 26.

[0037] The lower part of the pipette is operable via an operating element 12 and includes a displacement chamber 24 into which a piston connected to a plunger rod 22 enters. The lower part of the pipette further has a clamp section (Klemmbereich) for holding the pipette tip, and by acting the operating element 12, the used pipette tip can be released from the clamp section via an ejection linkage 19 and thereby dropped.

[0038] To change the pipetting volume of pipette 10, first, the lock slide 42 of the locking mechanism 40 is guided to the unlocked position. In this context, the “unlocked position” is understood to be the position of the locking mechanism that allows the operating element 12 to be rotated and, consequently, the pipetting volume to be changed. After setting the desired pipetting volume, the operating element 12 is then actuated to perform the pipetting operation. In this context, acting the operating element 12 is understood to mean pushing the operating element 12 down and displacing the operating element 12 axially along the longitudinal axis 72 of the associated pipette 10. The longitudinal axis extends from top to bottom in the plane of the drawing and runs from the operating element 12 through the upper pipette 21 and the lower pipette to the suction port at the end of the lower pipette, which is oriented away from the upper pipette 21.

[0039] Figure 2 shows a three-dimensional view of the locking mechanism 40 of the pipette 10 for locking a set pipetting volume. The locking mechanism 40 comprises a lock slide 42 and a lock ring 44 operably connected to the lock slide 42. The lock ring 44 locks the volume adjustment section 60 of the pipette 10 via the operating element 12, particularly by the lock slide 42 being pushed from the unlocked position to the locked position by the rotation of the operating button 14. The lock ring 44 and the counter wheels 32, 34, 36, and 38 of the counter 30 are located on a common counter shaft 31. The lock ring 44 is operably connected to a block element 50, which can engage with the counter wheels 32, 34, 36, and 38 of the counter 30, thus locking the volume adjustment section 60 of the pipette 10. The block element 50 has a bearing element 51 to which the block element 50 is rotatably mounted at a pivot point 52 inside the housing 20 of the pipette 10. The block element 50 has a first arm 53 that functions to lock the volume adjustment section 60. The block element 50 may also have a second arm 54 on the opposite side of the first arm 53, which can function to actuate the block element 50 or to press the block element 50 against the counter wheels 32, 34, 36, 38. The pipette 10 may further have a selector switch 28 that allows adjustment of different adjustment speeds for the volume adjustment section 60. In the embodiment shown in Figure 2, the locking mechanism 40 is shown in the unlocked state, in which the lock slide 42 is in contact with the second stop contour 48 of the lock ring 44, and the pipetting volume can be adjusted via the volume adjustment section 60.

[0040] Figure 3 shows another preferred embodiment of the locking mechanism 40 for a pipette according to the present invention. Essentially identical in configuration to Figure 2, this embodiment omits an additional selector switch 28 that allows for setting different adjustment speeds for the volume adjustment section 60. Therefore, any speed adjustment for the volume adjustment section is independent of the proposed locking mechanism 40. Furthermore, the locking mechanism 40 in Figure 3 is shown in the locked state, in which the lock slide 42 abuts against the first stop contour 46 of the lock ring 44, and the volume adjustment section 60 is locked.

[0041] Figure 4 shows a cross-section of the pipette 10 through the locking surface in the locked state of the locking mechanism 40, in which case the volume adjustment section 60 cannot be moved. A contour 74 extending radially inward on the lock slide 42 engages with a recess 70 between the first stop contour 46 and the second stop contour 48 on the lock ring 44. In the locked state, the contour 74 is pressed against the first stop contour 46 of the lock ring 44. An engagement lug 59 formed on the first arm 53 of the block element 50 is securely captured in the recess 56 by a catch contour 58 formed on the first stop contour 46, and an engagement contour 57 formed radially inward of the engagement lug 59 is pressed against a cam contour 39 on one of the counter wheels 32, 34, 36, and 38 of the counter 30. As a result, a shape-fit connection is established between the engagement lug 59 of the block element 50 and the cam contour 39 of the counter 30, locking the counter wheels 32, 34, 36, and 38 against rotation. The entire transmission system of the volume adjustment unit 60 is locked by fixing the counter wheels 32, 34, 36, and 38 of the counter 30, and the transmission gear 64 that engages with both the gear of the volume adjustment unit 60 and the counter 30. Therefore, it is no longer possible to rotate the operating button 14 connected to the volume adjustment unit 60, and the pipette 10 is protected from undesirable adjustments to the set pipetting volume. The catch contour 58 on the first stop contour of the lock ring 44 prevents the first arm 53 of the block element 50 and the engagement lug 59 formed thereon from deviating radially outward, thereby preventing the secure engagement between the engagement lug 59 and the cam contour 39 of the counter 30 from being disengaged. In this state, the block element 50 is preferably preloaded by the pressing element 68 so that the engagement lug 59 on the first arm 53 of the block element 50 is pressed against the counter wheels 32, 34, 36, and 38 of the counter 30. The pressing element 68 may be configured in particular as a torsion spring.

[0042] Figure 5 shows the locking mechanism of Figure 4 in the unlocked state, in which the pipetting volume can be adjusted by the elements of the volume adjustment section 60 for displacing the movable limiting portion of the operating button 14 and the plunger rod 22. A contour 74 extending radially inward on the lock slide 42 engages with a recess 70 between the first stop contour 46 and the second stop contour 48 on the lock ring 44. In the unlocked state, the contour 74 is pressed against the second stop contour 48 of the lock ring 44, and the lock ring 44 rotates so that the recess 56 on the catch contour 58 of the lock ring 44 no longer engages with the engagement lug 59. Although the engagement lug 59 is still pressed against the cam contour 39 of the counter 30 by the pressing element 68, its radially outward movement is no longer blocked. Therefore, when adjusting the pipetting volume, the engagement lug 59 lifts away from the cam contour 39 and engages with the next recess of the cam contour 39 as the volume adjustment unit 60 rotates further, thereby changing the pipetting volume by one unit. This process is repeated until the desired pipetting volume is set. If the user wishes to fix the newly set pipetting volume and protect the pipette 10 from unintended changes in pipetting volume, the lock slide 42 is pushed back to the locked position after volume adjustment, thereby re-securing the engagement lug 59 by the catch contour 58 and locking the rotation of the counter wheels 32, 34, 36, and 38 of the counter 30. [Explanation of Symbols]

[0043] 10: Pipette 12: Operation elements 14: Operation buttons 16: Finger hook 18: Ejector 19: Ejection Linkage 20: Housing 21: Top 22: Plunger Rod 24: Displacement Chamber 26: Restricted part of movement (verlagerbare Begrenzung) 28: Selector switch 30: Counter (Zaehlwerk) 31: Counter axis 32: First counter wheel 34: Second counter wheel 36: The third counter wheel 38: The fourth counterwheel 39: Cam contour 40: Locking mechanism 42: Rock Slide 44: Lock ring 46: First stopping contour 48: Second stopping contour 50: Block elements 51: Bearing element 52: Turning point 53: First Arm 54: Second Arm 56: Recess 57: Engagement contour 58: Catch Outline 59: Engagement lug 60: Volume adjustment section 62: Shaft 64: Transmission gear 66: Return elements 68: Pressure element 70: Recess 72: Longitudinal axis 74: Outline

Claims

1. A pipette (10), - A housing (20) for housing a displacement device, wherein the displacement device comprises a displacement chamber (24) and a movable limiting part (26) for limiting the pipetting stroke of the pipette (10), - An operating element (12) for setting the pipetting volume of the pipette (10) by moving the limiting portion (26) within the housing (20), and for performing a pipetting operation, wherein the operating element (12) is operably connected to a piston that is movable within the displacement chamber (24) of the displacement device, - A counter (30) for displaying the set pipetting volume, - A locking mechanism (40) for locking and / or unlocking the volume setting via the operating element (12) Equipped with, - A pipette (10) characterized in that the locking mechanism (40) comprises a lock slide (42) that interacts with a lock ring (44) which can be connected to the counter (30), and as a result, the lock ring (44) in a first position allows adjustment of the pipetting volume, and the lock ring (44) in a second position locks the rotation of the lock ring (44) and the counter (30) which can be connected to the lock ring (44).

2. The pipette (10) according to claim 1, characterized in that the locking mechanism (40) includes a blocking element (50) that prevents the rotation of the counter wheels (32, 34, 36, 38) of the counter (30) when the locking mechanism (40) is in the locked position.

3. The pipette (10) according to claim 2, characterized in that a first stop contour (46) and a second stop contour (48) are formed on the lock ring (44), and in the locked position of the lock mechanism (40), the lock slide (42) abuts against the first stop contour (46), and in the unlocked position, it abuts against the second stop contour (48) of the lock ring (44).

4. The pipette (10) according to claim 2 or 3, characterized in that the block element (50) has a bearing element (51) and at least one arm (53, 54) extending from the bearing element (51), and the block element (50) is rotatably attached to the bearing element (51).

5. The pipette (10) according to claim 4, characterized in that an engagement lug (59) is formed on the arm (53) of the block element (50), and the engagement lug (59) engages with a cam contour (39) on one of the counter wheels (32, 34, 36, 38).

6. The pipette (10) according to claim 5, characterized in that a catch contour (58) is formed on the first stop contour (46) of the lock ring (44), the catch contour (58) secures the engagement lug (59) and prevents the engagement lug (59) from lifting off the cam contour (39) on one of the counter wheels (32, 34, 36, 38).

7. The pipette (10) according to claim 6, characterized in that a recess (56) is formed on the catch contour (58), and the engaging lug (59) is at least partially housed within the recess (56) in the locked position of the locking mechanism (40).

8. The pipette (10) according to claim 6 or 7, characterized in that the catch contour (58) prevents the engagement lug (59) from moving radially outward, and as a result, the engagement contour (57) formed on the radially inward-facing surface of the engagement lug (59) is pressed against the cam contour (39) on one of the counter wheels (32, 34, 36, 38).

9. The pipette (10) according to any one of claims 4 to 8, characterized in that the block element (50) is biased by a pressing element (68), and as a result, the first arm (53) of the block element (50) is pressed against one of the counter wheels (32, 34, 36, 38) of the counter (30).

10. The pipette (10) according to any one of claims 5 to 9, characterized in that, in the unlocked position of the lock slide (42) of the locking mechanism (40), the engaging lug (59) can be moved radially outward, thereby enabling the rotation of the counter wheel (32, 34, 36, 38) of the counter (30) and the associated adjustment of the pipetting volume.

11. The pipette (10) according to any one of claims 1 to 10, characterized in that the counter wheels (32, 34, 36, 38) of the counter (30) engage with the transmission gear (64) of the volume adjustment unit (60).

12. A pipette (10) according to any one of claims 1 to 11, characterized in that a contour (74) extending radially inward from the lock slide (42) engages by shape fitting into a recess (70) between a first stop contour (46) and a second stop contour (48) on the lock ring (44).

13. The pipette (10) according to any one of claims 1 to 12, characterized in that the lock slide (42) of the lock mechanism (40) is oriented perpendicular to the longitudinal axis (72) of the pipette (10).

14. A pipette (10) according to any one of claims 1 to 13, characterized in that a finger hook (16) is formed on the housing (20), and the lock slide (42) of the locking mechanism (40) is positioned on the side of the housing (20) opposite to the finger hook (16).

15. The pipette (10) according to any one of claims 1 to 14, wherein the lock ring (44) is arranged coaxially with the counter wheels (32, 34, 36, 38) of the counter (30) on the counter shaft (31).

Images