Pipette, in particular piston stroke pipette, and use of a cover

Abstract

The invention relates to a pipette (1), comprising: - a housing (2), which has a proximal end (3) and a distal end (4) situated opposite said proximal end and which, in a handle region (5) of the pipette (1), can be gripped by a hand (H) of a person operating the pipette (1); - a pickup and ejection device (6) which is arranged in an interior of the housing (2) and by means of which a liquid to be pipetted can be picked up in or ejected from at least one pipette tip (7), wherein at least one coupling end (8) of the pickup and ejection device (6) protrudes beyond the distal end (4) of the housing (2) and can be clampingly coupled to a proximal end (9) of the at least one pipette tip (7); and - a syringe release device (10) by means of which a pipette tip (7) coupled to the coupling end (8) of the pickup and ejection device (6) can be released from the coupling end (8), wherein the pickup and ejection device (6) has an operator control knob (15), and the syringe release device (10) has a release knob (11). To reduce dosing inaccuracies resulting from warming of the pipette (1) caused by contact with the hand of the person operating the pipette (1), a cover (16) is proposed which forms at least a part of the handle region (5) of the pipette (1), wherein a slot (19) extends from a proximal end (24) of the cover (16) to the distal end of said cover and can be enlarged, and the cover (16) is thus elastically expanded, such that said cover can be pushed onto the housing (2).

Description

[0001] Pipette, in particular piston-operated pipette, and use of a sheath

[0002] Description

[0003] Introduction

[0004] The invention relates to a pipette, in particular a piston-operated pipette, comprising a housing having a proximal end and a distal end opposite the latter, which can be grasped in a gripping region of the pipette by a hand of a person operating the pipette, a receiving and dispensing device arranged in an interior of the housing, by means of which a liquid to be pipetted can be received into or dispensed from at least one pipette tip, wherein at least one coupling end of the receiving and dispensing device protrudes beyond the distal end of the housing and can be clamped to a proximal end of the at least one pipette tip, a tip ejection device with which a pipette tip coupled to the coupling end of the receiving and dispensing device can be ejected from the coupling end,wherein the receiving and dispensing device has an operating button preferably projecting beyond a proximal end of the housing and the tip ejection device has an ejection button preferably projecting beyond the proximal end of the housing, and wherein the pipette has a sheath which forms at least part of the grip area of ​​the pipette.

[0005] Furthermore, the invention relates to a tubular or groove-shaped casing for connection to a pipette, in particular to a piston-operated pipette, of the type described above.

[0006] State of the art

[0007] Pipettes are used in laboratories to dispense a wide variety of liquids. The pipettes in question here are primarily piston-operated pipettes (also called micro or microliter pipettes), which are also available in a special design known as multi-channel pipettes, or so-called handheld dispensers (multipettes, steppers, trackers, repeaters), which enable rapid work with microtiter plates or many parallel reaction mixtures. Piston-operated pipettes are used in conjunction with pipette tips that attach to their distal tip. These are disposable plastic items that only come into contact with the liquid to be dispensed during pipetting.In hand dispensers, a direct displacement reservoir, which is also a disposable plastic item and is constructed similarly to a syringe, takes over the function of the pipette tip and has a larger storage volume for repeated dispensing of a defined volume.

[0008] A key criterion for the quality of a pipette is the dispensing of a precisely defined amount of liquid, which is either fixed and unchangeable or adjustable. Dosing accuracy is often a key prerequisite for the quality and validity of the analysis performed using a pipette. Large-scale field trials have shown that dosing accuracy decreases over the course of a working day with the duration of pipette use. This undesirable circumstance jeopardizes the quality of the analysis when working with such a pipette for extended periods.

[0009] The prior art also includes the pipette according to DE 69728 186 T2, which has a sleeve-shaped housing part referred to as a frame in its handle area, which is provided with outwardly projecting longitudinal and transverse ribs to create a cross-sectional shape that deviates from a circular shape. Extending around this inner frame is a similarly sleeve-shaped membrane, arranged approximately coaxially to the frame and the longitudinal axis of the housing. This membrane is made of a foam material that acts as a cushion and is referred to as a membrane in the aforementioned publication. The membrane is intended to be bonded to the frame under heat and pressure, so that the aforementioned longitudinal and transverse ribs are embedded in the foam-like membrane material.The casing, which forms the outside of the pipette in the handle area and, thanks to its ribs, has a "bulged" and thus particularly ergonomic shape, is intended to support the user's grip, provide a particularly ergonomic shape, and thus reduce fatigue when working with the pipette, increase comfort, and prevent the development of so-called carpal tunnel syndrome.

[0010] The invention is based on the object of developing a pipette which can ensure the long-term stability of the dosing accuracy, ie even when working continuously for many hours in a day.

[0011] Solution

[0012] Starting from a pipette of the type described at the outset, this object is achieved according to the invention in that the casing has a slot running from a proximal end of the casing to its distal end, preferably parallel to the longitudinal axis of the housing, which slot can be enlarged and thus the casing can be elastically expanded such that it can be pushed onto the housing in a direction perpendicular or parallel to its longitudinal axis and / or to the longitudinal axis of the latter.

[0013] In this way, a casing can be created in a handle area of ​​the pipette, which can be connected to the pipette in a particularly simple manner, thus also enabling the retrofitting of an existing pipette with a casing. This is not possible with the manufacturing method of the pipette according to DE 697 28 186 T2, in which the casing is produced in one piece and as a closed sleeve using primary molding technology. While in the invention, the casing can be removed from the rest of the pipette due to elastic deformation, this is only possible in a destructive manner with the pipette previously known from DE 697 28 186 T2.

[0014] It was also discovered that dosing inaccuracies that occur when working with such a pipette for extended periods are due to heat input from the hand of the person operating the pipette. The hand heat is thus transferred from the hand to the grip area of ​​the housing and from there to the aspirating and dispensing device located inside the housing, where it leads to the aforementioned effect of a change in the amount of liquid (aspirated and) dispensed. Assuming a room temperature of around 20°C, at which all parts and components of a pipette are present at the start of use (in the stationary state of non-use), heat input from the hand of the person operating the pipette occurs when working with the pipette, where a hand surface temperature of around 30°C is assumed.During steady-state operation, which can occur after a prolonged period of several hours of use, a temperature increase of up to 10°C can occur in the intake and dispensing device, i.e., the dosing device, inside the pipette housing. This not insignificant temperature change leads to the aforementioned measurement or dosing inaccuracies.

[0015] This is now remedied by a covering – which can also be easily retrofitted – covering at least part of the pipette's handle area. The covering reduces the heat input from the handle area into the intake and dispensing device (dosing device), thus preventing any changes in the dispensed liquid volume over its service life. On the one hand, the covering can create additional resistance to heat conduction from the hand into the interior of the pipette. On the other hand, it can also complicate heat transfer due to an additional transition between two components (covering and housing), since contact or joint points exhibit poorer heat transfer behavior than areas with homogeneous material distribution without any material or component transitions.

[0016] In order to be able to benefit from the advantages of the invention even with existing pipettes without the need for a new design and with minimal effort, it is proposed that the casing be connectable to the housing, preferably by means of a force-fitting (frictional) and / or positive and / or material-fit connection, more preferably by means of a clip, clamp, snap-in, adhesive, bayonet, screw, or magnetic connection, and preferably detachable from the housing again in a non-destructive manner. Therefore, in this embodiment, implementing the invention with existing pipettes only requires the design and manufacture of a casing that fits the respective grip area of ​​the pipette.

[0017] For ergonomic reasons, the housing is approximately cylindrical in the grip area, preferably with an approximately oval cross-section, and has a longitudinal axis extending from the proximal end to the distal end of the housing. A casing adapted to this is particularly adapted to the outer surface of the pipette's housing and is therefore preferably also approximately cylindrical.

[0018] In order to minimize heat input into the pipette and at the same time to be able to exclude those zones of the handle area from the casing where there is no contact with the hand or fingers of the person operating the pipette, it is proposed that the slot be arranged on a side of the housing on which there is a free space between the fingertips and the ball of the hand when a person's hand is grasping the pipette, with the free space and the slot preferably being approximately congruent. This has the further advantage that, in the case of piston-operated pipettes with selectable or adjustable volume, a display for the currently set pipetting volume is often located in the said free space between the fingertips and the ball of the hand, so that this display is still visible and readable even after the casing has been applied.

[0019] If an outer surface of the housing in the handle area and / or an inner surface of the casing, which is in contact with the outer surface of the housing in the handle area in a connected state of casing and housing, has a roughness that is increased compared to the roughness of the outer surface of the casing and / or an outer surface of the housing in a remaining area, in particular is grooved, knurled or ribbed or microstructured, the heat transfer between the casing and the housing is further reduced by air inclusions in the boundary area between the two components (casing and housing) and the effect of dosing inaccuracy is thereby further minimized.

[0020] According to a further embodiment of the invention, a thermal insulation layer can be arranged between the casing and the housing, which preferably forms an entire contact area between the casing and the housing. The insulation layer is preferably a plastic film and / or is preferably firmly connected, in particular glued, welded, or sealed, to the outer surface of the housing in the handle area or to the inner surface of the casing. Materials with a low thermal conductivity coefficient or with good reflective properties (at least on their surface) with respect to radiation, in particular with respect to infrared radiation, are particularly suitable for the thermal insulation layer.

[0021] A particularly preferred embodiment of the casing is that it is trough-shaped and has two open end faces from which the pipette housing protrudes when the casing and housing are connected. Preferably, the casing has two, preferably ear-shaped, extensions at the proximal end, each extending essentially parallel to the longitudinal axis of the pipette and the longitudinal axis of the casing, which enclose a recess in the wall of the casing between them, from which a hook-shaped handle stop protrudes from the housing and projects radially outwards. Despite the complex geometry of a piston-operated pipette at its proximal end of the housing, the casing in this embodiment optimally fulfills its thermal insulation and shielding function and nevertheless in no way hinders the continued ergonomic operation of the pipette in laboratory operations.Particularly if the casing is designed as a retrofit component, it, and in particular its outer surface, can be provided with a marking and / or coding, in particular an inscription, embossing, a label, a special color that differs from the color scheme of the rest of the housing, or a barcode or QR code. In this case, the casing is also suitable as a carrier for customizing a pipette with specific information or a special design. These markings and / or coding can in particular be of an optical nature, but the integration of an electronic component, in particular an RFID chip, into the casing is also conceivable. In this way, customization can be easily achieved on the basis of a standard pipette, which can always be manufactured identically in large quantities, using cost-effective yet individually designed casings, particularly those in clip form.

[0022] In addition, the casing can also be used advantageously to improve the ergonomic design of the grip area of ​​existing (but also newly constructed) pipettes, namely by having a topography on its outer side adapted to the hand of the person grasping the pipette, in particular with groove-like depressions running in the circumferential direction of the grip area for inserting a finger of the hand and rib-like elevations arranged between two depressions and running parallel to these, each extending in the direction of spaces between adjacent fingers.

[0023] Finally, the object underlying the invention is achieved by using a sheath which is tubular or groove-shaped, has a longitudinal axis and a slot running from its proximal end to its distal end, which slot preferably runs parallel to the longitudinal axis and can be enlarged in a transverse direction, whereby the sheath is elastically expandable, for connection to a pipette which has a housing and a gripping area thereon, wherein the sheath, in an expanded state, can be pushed onto the latter in a direction perpendicular or parallel to its longitudinal axis and / or to the longitudinal axis of the housing of the pipette and, in a contracted state, is connected to the housing in a force-transmitting manner, wherein the sheath, in a state connected to the housing of the pipette, forms the gripping area.

[0024] Example

[0025] The invention will be explained in more detail below using an exemplary embodiment of a pipette, which is illustrated in the drawing. It shows: Fig. 1: a front view of the pipette with a pipette tip attached,

[0026] Fig. 2: like figure 1, but a top view,

[0027] Fig. 3: like figure 1, but a rear view,

[0028] Fig. 4: like figure 1, but a bottom view,

[0029] Fig. 5: a representation of a gripped by an operator’s hand

[0030] Pipette in the handle area and

[0031] Fig. 6: a clip-like cover for a pipette.

[0032] A pipette 1 shown in Figures 1 to 4 in the form of a piston-operated pipette with adjustable dosing volume (single-channel pipette) has a housing 2 having a proximal end 3 and a distal end 4 opposite the latter. As can be seen in particular from Figure 5, the pipette can be grasped in a gripping area 5 by a hand H of a person operating the pipette.

[0033] Located in a non-visible interior of the housing 2 is a main part of a receiving and dispensing device 6, which represents a dosing device and with which a preset volume of a liquid to be pipetted is taken up (sucked in) and dispensed (ejected) at another location. Only the protruding components of the receiving and dispensing device 6 are visible at the proximal end 3 and the distal end 4 of the housing, which will be discussed further below.

[0034] The liquid to be pipetted is picked up solely in the area of ​​a pipette tip 7, which can be attached to a coupling end 8 of the receiving and dispensing device 6 of the pipette 1 and is temporarily securely but releasably coupled via the coupling of two conical geometries at the distal end of the receiving and dispensing device 6 (i.e., the coupling end) on the one hand and the proximal end 9 of the pipette tip on the other. The coupling end 8 projects beyond the distal end 3 of the housing 2.

[0035] The pipette 1 further comprises a tip ejection device 10, which serves to eject a pipette tip 7 coupled to the coupling end 8 of the receiving and dispensing device 6 from the coupling end 8. This is achieved by moving an ejection button 11 belonging to the tip ejection device 10 relative to the housing in the direction of its distal end, ie, in the direction of the pipette tip 7.As a result, a tubular ejection sleeve 12, which has a thickened adjustment section at its proximal end, also moves towards the pipette tip 7 and, after bridging a certain idle stroke, comes into contact with a circular end face 13 with a likewise circular end face 14 of the pipette tip 7 and then pushes the latter down from the coupling end 8 of the receiving and dispensing device 6, so that the clamping connection is released and the pipette tip 7 falls off, which is a disposable part that is discarded after the pipetting process has ended.

[0036] The actual pipetting process is carried out in such a way that an operating button 15 protruding beyond the proximal end 3 of the housing 2, which is part of the intake and dispensing device 6, is first pressed towards the pipette tip 7 against the force of an invisible spring. The attached pipette tip 7 is then immersed in a liquid to be pipetted and the operating button 15 is released so that a previously set, precisely defined volume is sucked into the pipette tip 7. After the pipette tip has been moved to a dispensing location (e.g., via a test tube or similar), the operating button 15 is pressed again, whereby the liquid in the pipette tip 7 is forced out of the pipette tip 7 by means of air displacement. By means of an additional stroke in the direction of the pipette tip 7, a further volume of air can be passed through the pipette tip 7, whereby complete emptying of the residue is achieved.The control button 15 then moves back into its initial position shown in Figures 1 to 4 by simply releasing it due to spring force.

[0037] Arranged in the handle area 5 of the pipette 1 is a sheath 16, which is designed as a plastic injection-molded part and is shown as a separate part in Figure 6. The sheath 16 is firmly connected to the housing 2 of the pipette 1 by means of a clip connection (clamp connection) so that no relative movement can occur between the sheath 16 and the housing 2 when working with the pipette 1, so that the pipette 1 and the sheath 16 are perceived and felt as a single unit. Nevertheless, due to its clip nature, the sheath can be removed from the pipette 1 without causing damage.

[0038] As can be seen from Figure 6, the casing 16 has a longitudinal axis 17 which, in the assembled state of the casing 16, coincides with a longitudinal axis 18 (see Figure 1) of the pipette 1 or at least runs parallel to it. The housing 2 of the pipette 1 (without a casing 16 connected to it) is approximately cylindrical with an oval cross-section in the handle area 5. The cross-section of the casing 16 is adapted to the cross-section of the housing 2. In its form free from external forces, as shown in Figure 6, the casing 16 has slightly smaller internal dimensions than the external dimensions of the housing 2 in the handle area 5.In order to be able to mount the casing 16 on the pipette 1, the casing 16 has a slot 19 running parallel to its longitudinal axis 17, which can be enlarged by elastically expanding the casing 16 at its longitudinal edges 20, which delimit the slot 19 on each side, by movement in the direction of the arrows 21, so that it can be pushed onto the housing 2, preferably parallel to its longitudinal axis 18, from the pipette tip 7. After being pushed on, the casing 16 is sufficiently firmly connected to the housing 2 of the pipette by its elastic prestress as a result of the expansion, so that the latter two form a handling unit when the pipette 1 is used.

[0039] Again, from Figure 6 it can be seen that the casing 16 is trough-shaped and has two open end faces 22, 23, from which the housing 2 of the pipette 1 protrudes when the casing 16 and the housing 2 are connected, as can be seen in particular from Figure 5. Furthermore, and this is again best shown in Figure 6, the casing 16 has two ear-shaped extensions 25 at its proximal end 24, each of which extends essentially parallel to the longitudinal axis 17 of the casing 16 and the longitudinal axis 18 of the pipette 1. Furthermore, the two extensions 25 enclose a recess 26 in the wall 27 between them, from which - as can again be seen from Figure 5 - a hook-shaped handle stop 28 extending outwards in the radial direction protrudes from the housing 2.From Figure 6 it can also be seen that, in the assembled state of the casing 16, the slot 19 is arranged on a side of the housing 2 on which, when the hand H of an operator grasps the pipette 1, there is a free space 29 between the fingertips 30 and the ball of the hand 31. The free space 29 and the slot 19 are approximately congruent, so that in the area in which the outer surface of the pipette 1 in the grip area is not formed by the casing 16, there is no contact between the hand H and the pipette 1 and therefore no risk of heat transfer into the pipette 1. In the area of ​​the free space 29, a display is located in the housing 2 of the pipette 1, from which the currently set pipetting volume can be read. List of reference symbols.

[0040] 1 pipette

[0041] 2 housings

[0042] 3 proximal end

[0043] 4 distal end

[0044] 5 Grip area

[0045] 6 Receiving and Dispensing Facility

[0046] 7 Pipette tip

[0047] 8 Coupling end

[0048] 9 proximal end

[0049] 10 Tip ejection device

[0050] 11 Eject button

[0051] 12 Ejection sleeve

[0052] 13 Frontal surface

[0053] 14 Frontal surface

[0054] 15 Control knob

[0055] 16 Wrapping

[0056] 17 Longitudinal axis

[0057] 18 Longitudinal axis

[0058] 19 slot

[0059] 20 Longitudinal edge

[0060] 21 Arrow

[0061] 22 Front side 23 Front side

[0062] 24 proximal end

[0063] 25 extension

[0064] 26 Recess 27 Wall

[0065] 28 Handle stop

[0066] 29 open space

[0067] 30 fingertips

[0068] 31 Ball of the hand H Hand

Claims

Patent claims 1. Pipette (1), in particular a piston-operated pipette, with a housing (2) which has a proximal end (3) and a distal end (4) opposite the latter and is arranged in a The gripping area (5) of the pipette (1) can be grasped by a hand (H) of a person operating the pipette (1), a receiving and dispensing device (6) arranged in an interior of the housing (2), by means of which a liquid to be pipetted can be received into or dispensed from at least one pipette tip (7), wherein at least one coupling end (8) of the receiving and dispensing device (6) projects beyond the distal end (4) of the housing (2) and can be clamped to a proximal end (9) of the at least one pipette tip (7), a tip ejection device (10) with which a pipette tip (7) coupled to the coupling end (8) of the receiving and dispensing device (6) can be ejected from the coupling end (8),wherein the receiving and dispensing device (6) has an operating button (15) preferably protruding beyond a proximal end (4) of the housing (2), and the tip ejection device (10) has an ejection button (11) preferably protruding beyond the proximal end (4) of the housing, wherein the pipette (1) has a casing (16) which forms at least part of the grip region (5) of the pipette (1), characterized in that the casing (16) has a slot (19) extending from a proximal end (24) of the casing (16) to its distal end, preferably parallel to the longitudinal axis (18) of the housing (2), which slot can be enlarged and thus the casing (16) can be elastically expanded such that it can be pushed onto the housing (2) in a direction perpendicular or parallel to its longitudinal axis (17) and / or to the longitudinal axis (18) of the latter.

2. Pipette (1) according to claim 1, characterized in that the sheath (16) can be connected to the housing (2), preferably by means of a force-fitting (frictional) and / or form-fitting and / or material-fitting connection, more preferably by means of a clip, clamp, snap-in, adhesive, bayonet, screw or magnetic connection, and can preferably be detached from the latter again without causing any damage.

3. Pipette (1) according to claim 1 or 2, characterized in that the housing (2) in the handle area (5) is approximately cylindrical, preferably with an approximately oval cross-section, and has a longitudinal axis (18) running from the proximal end (3) to the distal end (4) of the housing (2) and the sheath (16) is adapted to the housing (2), in particular its outer surface, and is approximately cylindrical.

4. Pipette (1) according to claim 3, characterized in that the slot (19) is arranged on a side of the housing (2) on which, when a person's hand (H) grasps the pipette (1), there is a free space (29) between the fingertips (30) and the ball of the hand (31), wherein preferably the free space (29) and the slot (19) are approximately congruent.

5. Pipette (1) according to one of claims 1 to 4, characterized in that an outer circumferential surface of the housing (2) in the grip region (5) and / or an inner circumferential surface of the sheath (16), which is in contact with the outer circumferential surface of the housing (2) in the grip region (5) in a connected state of the sheath (16) and housing (2), has a roughness which is increased compared to the roughness of the outer circumferential surface of the sheath and / or an outer circumferential surface of the housing (2) in a remaining region, in particular is grooved, knurled or ribbed or microstructured.

6. Pipette (1) according to one of claims 1 to 5, characterized in that a thermal insulation layer is arranged between the casing (16) and the housing (2), which thermal insulation layer preferably forms an entire contact area between the casing (16) and the housing (2), wherein the insulation layer is preferably a plastic film and / or is preferably firmly connected, in particular glued or welded or sealed, to the outer surface of the housing (2) in the handle area (5) or to the inner surface of the casing (16).

7. Pipette (1) according to one of claims 1 to 6, characterized in that the casing (16) is trough-shaped and has two open end faces (22, 23) from which the housing (2) of the pipette (1) protrudes when the casing (16) and the housing (2) are connected, wherein the casing (16) preferably has at the proximal end (24) two preferably ear-shaped extensions (25) which each extend essentially parallel to the longitudinal axis (18) of the pipette (1) and the longitudinal axis (17) of the casing (16), which enclose between them a recess (26) in the wall (27) of the casing (16), from which recess a hook-shaped handle stop (28) protrudes from the housing (2) in a radially outward direction.

8. Pipette (1) according to one of claims 1 to 8, characterized in that the casing (16), in particular its outer surface, is provided with a marking and / or coding, preferably an inscription, embossing, a label, a special coloring that differs from the coloring of the rest of the housing (2) or a barcode or QR code.

9. Pipette (1) according to one of claims 1 to 9, characterized in that the casing (16) has on its outer side a topography adapted to the hand (H) of the person grasping the pipette (1), in particular with groove-like depressions running in the circumferential direction of the gripping region (5) for inserting a finger of the hand (H) and rib-like elevations arranged between two depressions and running parallel to these, each extending in the direction of spaces between adjacent fingers.

10. Use of a casing (16) which is tubular or groove-shaped, has a longitudinal axis (17) and a slot (19) extending from its proximal end (24) to its distal end, which slot preferably runs parallel to the longitudinal axis (17) and can be enlarged in a transverse direction (21), whereby the casing (16) can be elastically expanded, for connection to a pipette (1) which has a housing (2) and a gripping area (5) thereon, wherein the casing (16), in an expanded state, can be pushed onto the latter in a direction perpendicular or parallel to its longitudinal axis (17) and / or to the longitudinal axis (18) of the housing (2) of the pipette (1) and, in a contracted state, is connected to the housing (2) in a force-transmitting manner. is connected, wherein the casing (16) forms the grip region (5) when connected to the housing (2) of the pipette (1).

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