PIPETTE FOR USE WITH A PIPETTE TIP AND PIPETTE TIP FAMILY COMPRISING SEVERAL PIPETTE TIPS OF DIFFERENT TYPES FOR USE WITH A PIPETTE

Description

[0001] The invention relates to a pipette for use with a pipette tip. Furthermore, the invention relates to a pipette tip family comprising several pipette tips of different types for use with a pipette.

[0002] Pipettes are used primarily in scientific and industrial laboratories with medical, molecular biology, and pharmaceutical applications for dosing selected volumes of liquids. These liquids can be homogeneous (single-phase) liquids consisting of a single liquid component or a homogeneous mixture of several liquid components (solutions). Furthermore, the liquids can be heterogeneous (multiphase) mixtures of a liquid with another liquid (emulsions) or a solid (suspensions).

[0003] Pipettes have a stem-shaped pipette body with a stud (attachment) at the lower end for clamping a pipette tip. The stud is often conical, cylindrical, or partially conical and cylindrical and is also referred to as a "working cone." A pipette tip is a hollow tube with a tip opening at the lower end and a plug-in opening at the upper end, with which the pipette tip can be clamped onto the stud. The liquid is drawn into and dispensed from the pipette tip. The aspiration and dispensing of the liquid is controlled by the pipette. Fixed-volume pipettes are used for pipetting constant volumes. With variable-volume pipettes, the volume to be dispensed is adjustable. A mechanical counter is used to display the set volume. To set the volume, the stroke of the drive mechanism is adjustable using an adjustment device coupled to the counter.The pipette tip is removed from the tube after use and can be replaced with a fresh pipette tip. This prevents contamination during subsequent pipetting operations.

[0004] Air-cushion pipettes have a piston-cylinder system in the pipette body, which is connected via a channel to a hole in the stem. Pipette tips for air-cushion pipettes (air-cushion pipette tips) do not have an integrated piston. Moving the piston in the cylinder moves an air cushion to draw liquid into and expel it from a pipette tip clamped onto the stem. Disadvantages of air-cushion pipettes include dispensing errors due to changes in the length of the air cushion caused by the weight of the aspirated liquid and the influences of temperature, air pressure, and humidity. Contamination of the pipette by aerosols can also be problematic.

[0005] Positive displacement pipettes are used with pipette tips with an integrated piston (positive displacement pipette tips). This type of pipette features a stud for attaching the pipette tip and a drive mechanism that can be coupled to the integrated piston to move the piston. The piston comes into direct contact with the liquid, eliminating the effects of an air cushion. Positive displacement pipettes are particularly suitable for dispensing liquids with high vapor pressure, high viscosity, or high density, and for applications in molecular biology where aerosol-free operation is critical to avoid contamination.

[0006] Air cushion or positive displacement pipette tips for single use or reusable are made of plastic or glass.

[0007] Pipettes are available in different sizes, each with a matching pipette tip type or several matching pipette tip types with similar nominal volumes. For different applications, users must keep pipettes and pipette tips of different sizes on hand, which incurs corresponding costs for acquisition, maintenance, and storage. Color-coding pipettes and pipette tips is common practice to facilitate correct identification. This carries the risk of misinterpretation by the user.

[0008] EP 2 574 402 B1 describes a syringe for use with a dosing device that has a code on the upper edge of the syringe barrel that is dependent on the syringe type. Furthermore, a dosing device for use with a syringe is described that has a scanning device with a ring sensor for scanning the code, which is connected to an evaluation device that, in the event of error-free scanning, controls the dosing device to an operating state dependent on the code. This includes, for example, the display of the set dosing volume.

[0009] DE 199 48 818 A1 describes a syringe with a code on the upper end of the syringe plunger and a pipette ("syringe holder") with an information reader for reading the code. Upon detection of a specific syringe of a certain type, e.g., a 50 ml syringe, this value can be displayed via optical display elements (e.g., LEDs or LCDs).

[0010] WO 2011 / 110141 A1, SU 597 411 A1, and US 4,679,446 A describe air-cushion pipettes with attachments divided into multiple conical sections with steps in between, wherein the different conical sections have different clamping zones for clamping on pipette tips of different sizes. Several channels extend through the spigot, one of which opens into the central lower end face of the spigot and the others at the undersides of the steps. The other ends of the channels are connected to piston-cylinder systems. Due to the multiple channels in the spigot and the multiple piston-cylinder systems, these air-cushion pipettes are structurally complex. Clamping on pipette tips of different sizes is associated with different attachment forces due to the different clamping zones.

[0011] EP 0 152 120 A2 describes an air-cushion pipette comprising a digital linear drive module and connectable displacement modules of different sizes with conical pins for clamping pipette tips. A pipette tip of a specific size can be clamped onto the pins of each displacement module. To work with pipette tips of different sizes, the displacement module must be replaced with the displacement module that matches the respective pipette tip size.

[0012] US 2002 / 0001545 A1 and US 6,749,812 B2 describe an air-cushion pipette with an automatic tip ejector. It has a spring-loaded hub for attaching pipette tips and a spring-loaded ejector sleeve guided thereon. Furthermore, tip detection for pipette tips is provided, with different tip types having different base configurations. With this tip detection, different pipette tip types are recognized by a different displacement of the hub relative to the ejector sleeve, which is detected by an electronic sensor.

[0013] Conventional pipettes have the disadvantage that they rely on electronic sensors to detect pipette tips or syringes. These sensors detect both the displacement of the tip and the displacement of the ejector sleeve. These electronic sensors can be subject to severe stress from forces, vapors, etc., and are prone to failure. The electronic components increase the complexity and cost of the device. Furthermore, they limit the sterilization options. Different pipette tip types have different clamping surfaces on the tip.

[0014] Based on this, the invention aims to create a pipette that is less prone to failure and can be used with pipette tips of different types. Furthermore, a pipette tip family comprising several pipette tips of different types that can be used with the same, less prone to failure pipette is to be created.

[0015] The object is achieved by a pipette having the features of claim 1. Advantageous embodiments of the invention are specified in subclaims.

[0016] The pipette according to the invention for use with a pipette tip comprises: a stem-shaped pipette housing, a pin at the lower end of the pipette housing for clamping a pipette tip with a collar having a plug-in opening at its upper end, a drive device comprising a drive element for displacing a displacement element for sucking liquid samples into the pipette tip and ejecting the samples from the pipette tip, and an operating element protruding from the pipette housing and displaceable relative to the pipette housing, a scanning device with a scanning element arranged next to the pin and displaceable in the longitudinal direction of the pin relative to the pipette housing for displacement by the collar of a pipette tip when the pipette tip is clamped onto the pin, and a mechanical display device coupled to the scanning device, wherein the scanning device is designed to adjust a display of the display device,which depends on the position of the sensing element relative to the pipette body, for setting a display dependent on the type of pipette tip by clamping a pipette tip with a collar height characteristic of the type of pipette tip onto the pin.

[0017] The pipette according to the invention is suitable for use with a pipette tip from a pipette tip family. Pipette tips of different types can be clamped onto the stem of the same pipette. These form a pipette tip family. Pipette tips of different types differ in particular with regard to one or more of the following features: nominal volume, shape, dimensions, material (e.g. PP and / or PE), with or without coating, with or without surface treatment (e.g. treatment using pearl effect technology for better drainage of detergent-containing liquids), tubes with or without an inserted filter (filter tip), electrically insulating or electrically conductive, and degree of purity (e.g. standard, sterile, protein-free, PCR-pure, biologically pure). Pipette tips of different types have collars of different heights. Pipette tips of the same type have collars of the same height.The height of the collar is characteristic of the pipette tip type. The collar is the area at the top of the pipette tip with which the pipette tip protrudes from the stud or into which the stud dips when the pipette tip is clamped onto the stud. The pipette tip has a seating area on the inner circumference of the collar for clamping onto the stud. The sensing element is arranged next to the stud so that it can be displaced by the collar of a pipette tip when the tip is clamped onto the stud. This makes the sensing element suitable for displacement by the collar of a pipette tip clamped onto the stud. The sensing element can be displaced to varying degrees by collars of different heights. However, it can also be non-displaceable by a collar of low height and displaceable by one (or more) collars of different heights of greater height.The sensing device adjusts the display of the display device depending on the height of the collar detected by the sensing element. The display can include, for example, a volume display or an display of another feature of the pipette tip. The user can use pipette tips of different types and directly read a display dependent on the type used. The display is automatically adjusted to the type of pipette tip used. The mechanical display device is a display device in which the different displays are adjusted mechanically. To adjust the display, the display device is coupled to the sensing device. The display is adjusted by moving the sensing element. Since the pipette does not require an electrical sensor to detect the pipette tip type, the risk of failure is reduced.Another advantage is that the pipette can be designed purely mechanically without electronic components, so that there is no need to replace or recharge batteries and the sterilization options are expanded.

[0018] According to one embodiment of the invention, the display, which is dependent on the type of pipette tip, comprises or is a volume display. In this embodiment, the pipette tips of different types are pipette tips with different nominal volumes. The nominal volume is the volume of the pipette tip that can be used for pipetting. It is specified by the manufacturer and used to indicate the measuring range. According to another embodiment, the height of the collar increases with the nominal volume of the pipette tip. According to another embodiment, the height of the collar decreases with the nominal volume of the pipette tip. The volume display comprises at least one volume displayed by the display device.For a variable-volume pipette, this is the volume that can be dispensed with a pipette tip with a specific nominal volume at a specific setting of the adjustment device, and / or for a variable-volume or fixed-volume pipette, this is the nominal volume of the clamped-on pipette tip. As the nominal volume of the pipette tip increases, the volume display shifts to higher values.

[0019] This automatically adjusts the volume display to the pipette tip being used. The user can use pipette tips with different nominal volumes and read the set pipetting volume and / or nominal volume directly from the display without any interpretation effort.

[0020] According to a further embodiment of the invention, the mechanical display device displays a display dependent on a specific type of pipette tip when the sensing element is not displaced by the collar of a pipette tip attached to the pin. This is the case when no pipette tip is attached to the pin, or when a pipette tip with a short collar is attached to the pin that is not high enough to displace the sensing element. In both cases, the display device is adjusted to display a display dependent on the type of pipette tip with the short collar. In this case, the sensing element can be held by a stop device in an initial position from which it is not displaced when a pipette tip with the short collar is clamped onto the pin.When a pipette tip with a long collar is clamped onto the pin, high enough to displace the sensing element, the sensing device sets a reading that depends on the type of pipette tip with the long collar attached. In another embodiment, the reading of the indicator device is always adjusted when a pipette tip with a collar is attached to the pin.

[0021] According to another embodiment, the control element is coupled to the drive element. According to another embodiment, the control element is permanently connected to the drive element or coupled to it via a gear.

[0022] According to one embodiment of the invention, the pipette is an air-cushion pipette for use with an air-cushion pipette tip. According to another embodiment, a displacement device is arranged in the pipette housing and is connected via a channel to a hole at the lower end of the pin. According to another embodiment, the displacement device is a displacement chamber with a displaceable displacement element therein. According to another embodiment, the displacement device is a cylinder with a displaceable piston sealingly guided therein. According to another embodiment, the drive element is a lifting rod that can be displaced vertically in the pipette housing and is coupled at the lower end to the displacement element and at the upper end to the operating element. According to another embodiment, the operating element is an operating button that protrudes from the upper end of the pipette housing and can be pressed at least partially into it.

[0023] According to another embodiment, the pipette is a positive displacement pipette for use with a positive displacement pipette tip. According to another embodiment, the drive element is a lifting rod guided in a vertical through-channel of the pin, with a vertical bore at the lower end for clamping a piston rod protruding from the top of the integrated piston of a pipette tip. According to another embodiment, the upper end of the lifting rod is coupled to the operating element. According to another embodiment, the operating element is an operating button that protrudes from the upper end of the pipette housing and can be pressed at least partially into the pipette housing.

[0024] According to another design, the pipette is a fixed-volume pipette. With a fixed-volume pipette, the drive element can be moved back and forth by a defined measuring stroke. When designed as a positive-displacement pipette, the pipette can be used with positive-displacement pipette tips that have different tube diameters and correspondingly adapted piston diameters, allowing different volumes to be pipetted with the same measuring stroke. According to another design, the fixed-volume pipette has a display device that shows the nominal volume of a pipette tip clamped onto the attachment.

[0025] According to a further embodiment, the pipette is a variable pipette. This has an adjustable volume. According to a further embodiment, the measuring stroke of the pipette is adjustable. According to a further embodiment, the pipette has a display device that shows the set measuring stroke. According to a further embodiment, the display device comprises a counter. According to a further embodiment, the variable pipette comprises a first setting element for setting the volume, which is arranged at the upper end of the pipette housing. According to a further embodiment, the first setting element is simultaneously the operating element or an additional component. When designed as an additional component, the first setting element is, for example, a sleeve-shaped setting knob that is rotatably mounted at the upper end of the pipette housing and surrounds an operating button, wherein the operating button can be pressed at least partially into the setting knob.According to another embodiment, the variable pipette has a display device that indicates the nominal volume of a pipette tip clamped onto the attachment. According to another embodiment, the display device shows the nominal volume in addition to the set volume.

[0026] According to another embodiment, the pipette has a piston spring that, after the operating element is relieved of pressure, displaces the drive element upwards until a first stop device becomes effective (strikes). By actuating the operating element, the lifting rod can be displaced downwards, counteracting the action of the piston spring, until a second stop device becomes effective (strikes). According to another embodiment, the operating element is coupled to the drive element via a gear, which allows the drive element to be driven in different directions.According to a further embodiment, the drive device comprises a switching device, so that when the operating element is actuated, the drive element can first be displaced downwards until the second stop device becomes effective and when the operating element is actuated further, the switching device controls the displacement of the drive element in the opposite direction until the first stop device becomes effective.

[0027] According to a further embodiment, the nominal volumes of the pipette tips or other characteristics characterizing the type of pipette tips that can be used with the pipette are indicated on the pipette and / or the pipette is provided with one or more markings indicating the nominal volumes or other characteristics characterizing the type of pipette tips that can be used with the pipette. According to a further embodiment, the nominal volumes or other characteristics characterizing the type are indicated on the pipette tips and / or the pipette tips are provided with one or more markings indicating the nominal volumes or other characteristics characterizing the type.

[0028] According to a further embodiment, the pin is rigidly connected to the pipette housing, wherein the pin is preferably not movable relative to the pipette housing. The pin can be directly or indirectly connected to the pipette housing. In particular, the pin can be rigidly connected to a frame or chassis that supports the pipette housing and is rigidly connected to it.

[0029] According to a further embodiment, the sensing device comprises a slider guided vertically on the pipette housing, which has the sensing element at the lower slider end and whose upper slider end is coupled to the display device. In this embodiment, by clamping pipette tips with collars of different heights onto the pin, the lower slider end, and thus the slider, can be displaced upwards to varying degrees. During the displacement, the upper slider end acts on the display device and adjusts the volume display or another display depending on the type of pipette tip accordingly.

[0030] According to a further embodiment, the slider has various nominal volume information or various other information characterizing the type of pipette tip on an outer side in a vertical direction, and the pipette housing has a window in the displacement area of ​​the nominal volume information or the other information on the slider, through which only a complete nominal volume information or a complete other information on the slider is visible from the outside. The nominal volume information or other information and the window are arranged in such a way that for each pipette tip attached to the pin, the corresponding nominal volume information or other information is visible from the outside through the window. This is controlled by the height of the collar of the pipette tip. This makes it easy for the user to see which pipette tip type is attached.

[0031] According to the invention, the pipette comprises a first stop device with a first stop element on the drive device and a second stop element on the pipette housing, which can be brought into contact with one another by displacement of the drive element in a first direction, and a second stop device with a third stop element on the drive device and a fourth stop element on the pipette housing, which can be brought into contact with one another by displacement of the drive element in a second direction, which is opposite to the first direction, in order to define a measuring stroke of the drive device together with the first stop device.

[0032] According to the invention, the pipette comprises an adjustment device with a first adjustment element mounted on the pipette housing and a second adjustment element on the first or second stop device for adjusting the measuring stroke by adjusting the first adjustment element and a mechanical counter coupled to the adjustment device for displaying the setting of the adjustment device, wherein the scanning device is coupled to a mechanical range adjustment device on the counter, which is designed to set a counting range of the counter which depends on the position of the scanning element relative to the pipette housing.

[0033] According to a further embodiment, the range adjustment device comprises a marking arranged outside the counter at the upper end of the slide, whereby, when pipette tips with collars of different heights are clamped onto the pin, the slide can be displaced upwards to different distances in order to position the marking to indicate different counting ranges laterally next to or between different positions on the counter. In this embodiment, collars of different heights position the marking to the side next to or between different positions on the counter, i.e., to the side next to or behind the first decimal place and / or to the side next to or in front of the first decimal place. In Depending on the height of the collar, the marking can be adjusted so that the counter directly indicates the volume that can be pipetted with the attached pipette tip at the given stroke setting. This allows the counter's counting range to be shifted by one or more orders of magnitude. This allows pipette tips with nominal volumes that differ by one or more orders of magnitude to be used with the same pipette.

[0034] According to another embodiment, the range setting device comprises a switchable gear mechanism through which the counter is coupled to the setting device. By switching the switchable gear mechanism, various gear ratios can be selected. In Depending on the height of the collar, the gear can be switched so that the counter shows the volume that can be pipetted with the attached pipette tip at the given setting of the measuring stroke.

[0035] According to a further embodiment, the sensing element is formed at the lower slide end of a slide sleeve, which is vertically movable along a housing shaft of the pipette housing, which has a pin at its lower end. The slide sleeve is guided particularly easily and precisely along the housing shaft.

[0036] According to a further embodiment, the marking is a boundary of a diaphragm connected to the upper end of the slide. Digits of the counter are readable from the outside through the diaphragm and a window in the pipette housing. According to a further embodiment, the diaphragm is adjusted by the slide so that only the digits that indicate the set pipetting volume for the attached pipette tip are readable and / or framed by the diaphragm, and / or the marking indicates the first digit before the decimal point and / or the highest digit after the decimal point. According to a further embodiment, the digits of the counter or the counter rollers are arranged one above the other. According to another embodiment, the digits of the counter or the counter rollers are arranged next to each other in a horizontal direction.In this design, the marking is connected to the upper end of the slider via a transmission mechanism, which converts a vertical displacement of the upper end of the slider into a horizontal displacement of the marking. According to another design, the marking is a bar-like graduation mark in a frame of the aperture, which can be positioned behind the smallest pre-decimal place of the counter mechanism and / or before the highest decimal place of the counter mechanism, which applies to a clamped pipette tip.

[0037] According to a further embodiment, the pipette comprises a first spring device with a first engagement point on the pipette housing and a second engagement point on the drive device in order to displace the drive element in the first direction until the first stop element rests on the second stop element when the operating element is relieved.

[0038] According to a further embodiment, the first spring device is a first coil spring, which is supported at its lower end by a first spring bearing on the housing and at its upper end by a second spring bearing on the lifting rod. According to a further embodiment, the lifting rod is guided through the first coil spring.

[0039] According to a further embodiment, the operating element is also the first adjustment element, wherein the operating element is rotatably mounted in the housing and coupled to the second adjustment element via a first gear. According to a further embodiment, the first gear comprises a spindle nut, a threaded spindle which is threadably engaged with the spindle nut, vertically aligned, and rotatably coupled to the operating element, having a longitudinal bore through which the lifting rod is passed, and a linear guide which is aligned vertically in the pipette housing and on which the spindle nut is guided. Here, the spindle nut is the second adjustment element, the lower end face of the spindle nut is the first stop element, and a bead protruding radially from the lifting rod below the spindle nut is the second stop element.

[0040] According to a further embodiment, the mechanical counter is coupled via a second gear to the setting knob or operating knob rotatably mounted in the housing.

[0041] A further embodiment has a third stop device with a fifth stop element on the slide and a sixth stop element on the pipette housing, and a second spring device with a third engagement point on the pipette housing and a fourth engagement point on the slide to apply downward pressure to the slide and to engage the fifth stop element against the sixth stop element when no pipette tip is attached to the pin. This holds the slide in a defined lower stop position before a pipette tip is attached, from which the slide can be moved upward by attaching the pipette tip to the pin.

[0042] According to another embodiment, the second spring device is a second coil spring, which is held at the lower end by a third spring bearing on the slide and at the upper end by a fourth spring bearing on the housing. This embodiment is structurally simple and space-saving.

[0043] To clamp the piston rod into the bore of the lifting rod, after clamping the pipette tip, the lifting rod can be moved downwards by pressing the control button until the second stop device becomes active. This can be done immediately before the liquid is drawn into the pipette tip. To draw the liquid, the user simply needs to release the control button, as the first spring mechanism moves the lifting rod upwards. Pressing the control button again dispenses the liquid from the pipette tip.

[0044] The pipette tip can be removed from the pipette manually.According to a further embodiment of the positive displacement pipette, ejection of the pipette tip with integrated piston by the operating element is made possible in that the lifting rod has a lower lifting rod part, the vertical bore extends to the upper end of the lower lifting rod part, an upper lifting rod part engages in the vertical bore and a third spring device is integrated into the upper lifting rod part, which third spring device is designed such that by pressing the operating element downwards, the upper lifting rod part can initially be displaced downwards in parallel with the lower lifting rod part until the third stop element rests against the fourth stop element and when an increased pressure force is applied to the operating button, the third spring device compresses so that the upper lifting rod part penetrates deeper into the lower lifting rod part, whereby the piston rod is pushed out of the vertical bore and the pipette tip is pushed off the pin.

[0045] According to a further embodiment, the air cushion pipette has an ejector which enables the pipette tip to be released by actuating the operating element and / or an additional ejector button.

[0046] According to another embodiment, the slider is connected at the top to an ejector button protruding from the upper end of the pipette housing. When actuated, the slider can be moved downwards to allow the lower end of the slider to strip a pipette tip from the stem. The slider thus forms an ejector, allowing pipette tips to be detached from the stem without touching them with the hand.

[0047] To release the integrated piston from the lifting rod, the withdrawal of the piston from the pipette tip can be limited by a stop so that the piston is separated from the lifting rod by stripping off the pipette tips.

[0048] A further embodiment has a fourth stop device with a seventh stop element on the ejector button and an eighth stop element on the housing, which are designed to limit the upward displacement of the ejector button and a transmission device between the ejector button and slider, which is designed to prevent the ejector button from displacing upwards when the slider is displaced upwards and to displace the slider downwards when the ejector button is displaced downwards. As a result, the starting position of the non-actuated ejector button is not changed by the upward displacement of the slider. As a result, the ejector button does not assume different starting positions when pipette tips with collars of different heights are attached. Furthermore, the path of the ejector button for stripping a pipette tip from the pin can be kept constant regardless of the pipette tip used.Compared to designs in which the release button and slider are rigidly connected, the ease of use and the visual appearance are improved.

[0049] According to a further embodiment, (i.) the transmission device is a fourth spring device having a fifth engagement point on the release button and a sixth engagement point on the slide, whereby upon upward displacement of the slide, the fourth spring device is compressed, and upon downward displacement of the release button, the fourth spring device is first compressed and then the release button carries the slide, or (ii.) the transmission device is a locking device arranged between the release button and the slide, which enables upward displacement of the slide relative to the release button and prevents downward displacement of the push button relative to the slide. According to a preferred embodiment, the locking device is a directional locking mechanism.

[0050] In both variants (i.) and (ii.), the upward displacement of the release button is limited by the fourth stop device. Thus, it assumes a defined upper stop position from which it can be moved downward.

[0051] In variant (i.), the ejection button and ejection rod are not rigidly coupled to one another, but via a fourth spring device. The fourth spring device can in particular be a (helical) spring or a flexible element (e.g. an element made of rubber, silicone or a thermoplastic elastomer). The ejection button and slider are only slightly spaced from one another, so that when the ejection button is actuated, the fourth spring device is compressed first and when the ejection button comes into contact with the slider, the latter is also moved downwards. On the other hand, an upward movement of the slider when attaching a pipette tip does not lead to an upward movement of the ejection button, since the fourth stop device prevents this and only the fourth spring device is compressed.

[0052] In variant (ii.), the ejector button and the slider are connected to each other via a locking device. The locking device has the function of preventing the movement of a component in a certain direction, while allowing movement in the opposite direction. The locking device comprises, for example, a gear wheel mounted on the ejector button, which has a freewheel. The slider is provided with teeth on one side like a rack. When a pipette tip is attached, the ejector is moved upwards and the gear wheel rotates freely. When the ejector button is pressed, however, the free rotation of the gear wheel is stopped and the slider is moved downwards so that the lower end of the slider wipes the pipette tip off the pin.

[0053] Another embodiment has, in addition to the slide, an ejection slide which is guided vertically on the pipette housing and which is connected at the upper end to the ejection button and whose lower end is arranged next to the pin, offset radially to the lower end of the slide, whereby (i.) the lower ends of the slide and the ejector slide are arranged at the same height, so that by clamping a pipette tip with two circumferential steps at the upper end onto the pin, the slide can be moved by the inner step and the ejector slide cannot be moved by the outer step, and by pressing the ejector button the lower end of the ejector slide can be pressed against the outer step of the pipette tip in order to strip the tip off the pin, or (ii) the lower end of the slide is arranged lower than the lower end of the ejector slide, so that by clamping a pipette tip with a flat upper edge onto the pin, the slide can be moved upwards and the ejector slide cannot be moved upwards, and by pressing the ejector button the ejector slide can be pressed against the upper end of the pipette tip and the pipette tip can be stripped off the pin.

[0054] In this design, the range setting and ejection of the pipette tip are achieved by an ejector slide that is separate from the slide and one from it. This can, for example, be an outer and an inner slide sleeve, with the inner slide sleeve being guided on a shaft of the pipette and the outer slide sleeve on the inner slide sleeve. While one slide sleeve is moved upwards when the pipette tip is attached and moves the range setting, the other slide sleeve is not moved. This slide sleeve is only used when the ejector button is pressed. In variant (i.) this is achieved by the pipette tip having two concentric circumferential steps at the upper end, with the step that projects further up actuating the range setting and the lower end of the ejector slide meeting the step that projects less upwards. In variant (ii.)) this is achieved by the fact that when not actuated the slider protrudes further downwards than the ejection slider, so that by attaching a pipette tip with a flat upper edge the slider and not the ejection slider is displaced.

[0055] According to a further embodiment, the attachment has a circumferential shoulder at a distance from its lower end on the outer circumference, so that a pipette tip can be clamped onto the attachment using an upper edge of the collar or a circumferential inner step projecting radially inwards on the inner circumference of the collar until the inner step rests against the shoulder. This ensures that the attachment always engages the clamped-on pipette tip of the respective type to the same depth. If the collar of the pipette tip has an expanded section above the inner step and the attachment above the shoulder is not expanded to match the collar, the pipette tip can only be clamped onto the attachment with a seating area below the inner step.Even though the pipette tip can be pushed onto the hub until the upper edge of the collar rests on the shoulder, it can only be clamped onto the hub with a seating area below the upper edge of the collar. This ensures that pipette tips of different types, with collars of different heights, are clamped onto the hub with equal firmness. This is advantageous for securely clamping pipette tips onto the hub and releasing them from the hub without excessive force. In the designs of the pipette tip family explained below, in which the pipette tips can be pushed onto the hub until the upper edge of the collar or an inner step of the collar rests on the shoulder, the upper edge of the collar or the inner step is referred to as the "ninth stop element."

[0056] According to another embodiment, the pipette is a single-channel pipette. A single-channel pipette has only a single attachment at the lower end of the housing for clamping on a pipette tip. According to another embodiment, the pipette is a multi-channel pipette. A multi-channel pipette is a pipette that has several parallel attachments at the lower end of the pipette housing for simultaneously clamping on several pipette tips. In this embodiment, the scanning device can, in particular, have a scanning element arranged next to only one or next to several pins.

[0057] Furthermore, the object is achieved by a pipette tip family having the features of claim 17. Advantageous embodiments of the pipette tip family are specified in subclaims.

[0058] The pipette tip family according to the invention for use with a pipette comprises at least two pipette tips of different types, each pipette tip having a tip opening at the lower end, a collar having a plug-in opening with a height at the upper end that characterizes the type of pipette tip, and a seating area on the inner circumference of the collar for clamping onto a stud having a specific contour of a pipette, wherein pipette tips of different types can be clamped with their seating area onto the same clamping zone of the stud, so that they stand up with their collar at different heights on the stud.

[0059] The collar is the area at the top of the pipette tip with which the pipette tip protrudes from the stem or into which the stem dips when the pipette tip is clamped onto the stem. The height of the collar can be measured starting from the seat area of ​​the pipette tip, which is formed, for example, by a circumferential bead on the inner circumference of the collar. Pipette tips of different types can be clamped with their seat areas onto the same clamping zone of the stem, so that the distance between the top of the collar and the seat area increases proportionally to the immersion depth of the stem in the collar. In this pipette tip family, pipette tips with collars of different heights control a sensing element of a sensing device on the pipette in such a way that the sensing device sets a display on a display device on the pipette that depends on the type of pipette tip.As a result, when different types of pipette tips are clamped onto the tip, the indicator is set to indicate the type of pipette tip currently attached. Pipette tips in the pipette tip family can be air-cushion or positive displacement pipette tips. Positive displacement pipette tips have a cylindrical piston track between the tip opening and the attachment opening, as well as an integrated piston that can be moved along the piston track.

[0060] Pipette tips of different types differ in particular with regard to one or more of the following characteristics: nominal volume, shape, dimensions, material (e.g. PP and / or PE), with or without coating, with or without surface treatment (e.g. treatment using pearl effect technology for better drainage of detergent-containing liquids), tubes without or with an inserted filter (filter tip), electrically insulating or electrically conductive, degree of purity (e.g. standard, sterile, protein-free, PCR-pure, biologically pure).

[0061] According to a further embodiment, the pipette tip family comprises at least two pipette tips with different nominal volumes, wherein the pipette tips with different nominal volumes can be clamped onto the same pin with their seating area, so that their collars protrude at different heights from the pin. In this pipette tip family, pipette tips with collars of different heights control a sensing element of a sensing device of the pipette such that the sensing device sets or maintains the volume display of a display device of the pipette depending on the height of the collar. Consequently, when pipette tips with different nominal volumes are clamped onto the attachment, the corresponding volume display is always displayed.

[0062] According to one embodiment, the pipette tip family includes pipette tips whose nominal volumes differ by one or more orders of magnitude. These pipette tips are usable with a pipette with a mechanical counter to set a mark on the sensing device next to one of the counter rollers. In this pipette tip family, the heights of the collars differ by a multiple or an integer multiple of the height of a counter roller.

[0063] Because pipette tips of different types can be clamped onto the same clamping zone of the same pin with their seating area, it is possible to achieve a situation where pipettes of different types can be clamped onto the pin with the same clamping forces. This is advantageous for equally secure clamping of pipette tips of different types onto the pin. The clamping zone is a continuous zone of the pin that runs around the pin, is free of steps. According to a further embodiment, pipette tips of different types are designed such that they can only be clamped onto the same clamping zone of the pin. In this embodiment, pipette tips of different types cannot be clamped onto zones other than the clamping zone of the pin, thereby achieving identical clamping forces. With air-cushion pipette tips, this allows a tight fit on the pin with identical clamping forces.According to a further embodiment, the seating area of ​​the pipette tip includes a circumferential bulge and / or a circumferential groove. According to a further embodiment, a bulge of the seating area of ​​a pipette tip engages a groove of the clamping area on the pipette stem and / or a bulge of the clamping area engages a groove of the seating area.

[0064] According to a further embodiment, the height difference between the collars is a multiple or an integer multiple of the height of a counter roller, which is in the range of 1 to 7 mm, in particular in the range of 3 to 5 mm, and preferably 4.5 mm. In these ranges, the digits of the counter wheels are clearly visible while maintaining a compact design.

[0065] The pipette tips of the pipette tip family according to the invention have, in addition to the attachment opening on the inner circumference, a seating area with which they can be clamped onto the spigot of a pipette. The seating area is adapted to the contour of at least part of the spigot. For this purpose, the seating area can either have a contour complementary to the contour (e.g. a cylindrical or conical contour) of at least part of the spigot or have protruding sealing and / or guiding structures (e.g. sealing and / or guiding beads) on its inner circumference that are adapted to the contour (e.g. a cylindrical or conical contour) of at least part of the spigot. The pipette tips with different nominal volumes can be clamped onto the same spigot with their seating area, so that their collars protrude from the spigot at different heights.

[0066] According to a further embodiment, the clamping onto the attachment of a pipette is determined by a ninth stop element, which limits the sliding of the pipette tip onto the pipette stud by resting on the pipette. The ninth stop element is, for example, an inner step of the pipette tip that runs around the inner circumference of the pipette tip and projects radially inwards, which comes to rest on the lower end of the stud, or a downwardly tapered conical braking area of ​​the pipette tip that comes to rest on the lower end of the stud. The ninth stop element can be designed in the above manner for both an air cushion and a positive displacement pipette tip. In a positive displacement pipette tip, according to a further embodiment, the ninth stop element is an upper side or a circumferential, radially outwardly projecting shoulder of the piston or piston rod, which comes to rest on the pipette's lifting rod.

[0067] According to a further embodiment, the ninth stop element is an upper edge of the collar or a circumferential inner step of the pipette tip that projects radially inward on the inner circumference of the collar, above which the collar has an expanded section, so that the pipette tip can be clamped onto a pipette attachment until the upper edge of the collar or the inner step rests against a seating area arranged below the upper edge of the collar or the inner step, until the upper edge of the collar or the inner step rests against a shoulder of the attachment. This embodiment ensures that pipette tips of a certain type can be pushed onto an attachment at the same height. The upper edge of the collar can control the scanning element of a scanning device, regardless of whether the upper edge of the collar or the inner step rests against the shoulder.According to a further embodiment, the pipette tips are designed such that the pipette tips can only be clamped onto the attachment with a seating area below the upper edge of the collar or below the inner step, and cannot be clamped onto the attachment with the extended section of the collar above the inner step. According to a further embodiment, the pipette tips are designed such that they can be clamped onto a cylindrical or conical section of an attachment below a shoulder of the attachment. According to a further embodiment, the pipette tips are designed such that they cannot be clamped onto a cylindrical or conical section of the attachment above the shoulder with an extended section of the collar above the inner step.According to a further embodiment, the extended section of the collar above the inner step is configured such that a gap exists between the extended section of the collar and an extended section of the hub above the shoulder when the pipette tip is clamped onto the hub. This allows pipette tips of different types to be clamped onto the same hub with equal tightness. This promotes secure clamping onto the hub and easy release of the pipette tips from the hub without excessive force.

[0068] According to another embodiment, the seating area extends to the upper edge of the collar, with which the pipette tip can be clamped onto the hub until it rests against the shoulder. According to another embodiment, the seating area extends to the inner step, with which the pipette tip can be clamped onto the hub until it rests against the shoulder.

[0069] According to another embodiment, the pipette tip family comprises a pipette tip configured to be pushed onto the neck until the upper edge of the collar rests against a shoulder, and at least one pipette tip of a different type configured to be pushed onto the neck until the inner step rests against a shoulder. According to another embodiment, the pipette tip family comprises at least two pipette tips of different types configured to be pushed onto the neck of a pipette until the inner step rests against a shoulder.

[0070] According to another embodiment, each pipette tip has two concentric circumferential steps along its upper edge, with one step protruding further from the lower syringe opening than the other. These pipette tips are advantageous for pipettes in which the ejection button maintains the same position when not actuated, regardless of the height of the collar of the attached pipette tip.

[0071] According to a further embodiment, the pipette tip family comprises pipette tips with at least two of the following nominal volumes: 10 µl, 25 µl, 100 µl, 250 µl or 1,000 µl.

[0072] According to another embodiment, the pipette tip family includes pipette tips with nominal volumes of 10 µl, 100 µl, and optionally 1,000 µl, or 25 µl and 250 µl. A particular advantage of these designs is that the mechanical display device can change the volume display for pipette tips with different nominal volumes by adjusting the marking to different decimal places.

[0073] Furthermore, the invention relates to a pipette system comprising a pipette according to one of claims 1 to 16 and at least one pipette tip from the pipette tip family according to one of claims 17 to 23. The pipette system has the advantages of the pipette according to one of claims 1 to 16 and the pipette tips of the pipette tip family according to one of claims 17 to 23.

[0074] The invention is explained in more detail below with reference to the accompanying drawings of exemplary embodiments of the invention. In the drawings: Fig. 1: a positive displacement pipette in a non-actuated state in a vertical section; Fig. 2: the same positive displacement pipette with a pipette tip clamped on and coupled to the drive device in a vertical section; Fig. 3: the same positive displacement pipette ejecting a pipette tip in a vertical section; Fig. 4: the same positive displacement pipette with a 10 µl pipette tip attached without a housing ( Fig. 4a ) and with housing ( Fig. 4b ) each in a perspective side view and enlarged detail of Fig. 4a (Fig. 4c ); Fig. 5 the same positive displacement pipette with a 100 µl pipette tip attached without housing ( Fig. 5a ) and with housing ( Fig. 5b ) each in a perspective side view and enlarged detail of Fig. 3a ( Fig. 5c ); Fig. 6-8 the same positive displacement pipette with attached pipette tip with a nominal volume of 10 µl ( Fig. 6 ), 100 µl ( Fig. 7 ) and without attached pipette tip ( Fig. 8 ), each in a front view; Fig. 9-10Shaft of the same positive displacement pipette with attached pipette tip with a nominal volume of 10 µl ( Fig. 9 ) and 100 µl ( Fig. 10 ) in a vertical section; Fig. 11Transmission device with spring between ejection button and ejection slide of an air cushion pipette in a rough schematic representation; Fig. 12Transmission device with locking device between ejection button and slide of an air cushion pipette in a rough schematic representation; Fig. 13Enlarged detail of Fig. 12 ; Fig. 14 an air cushion pipette with separate scanning device and ejection device and pipette tip with steps at the upper end in a roughly schematic side view; Fig. 15-17 a direct displacement pipette with operating lever and switching device for moving the piston in both directions in front view ( Fig. 15 ), side view ( Fig. 16 ) and perspective view from the front and side ( Fig. 17 ).

[0075] In this application, the terms "top" and "bottom," "vertical" and "horizontal," and derived terms such as "above" and "below" and "one above the other" refer to an arrangement of the positive displacement pipette in which the plug is vertically aligned and located at the downward-facing end of the pipette body. With regard to the pipette tip, these terms refer to a vertical alignment of the pipette tip's central axis, with the tip opening at the bottom and the plug-in opening at the top.

[0076] According to Fig. 1 A pipette 1 designed as a positive displacement pipette has a substantially stem-shaped pipette housing 2, the upper part of which is shaped as a handle 3 and the lower part as a shaft 4. A pin 5, tapering downwards in steps, protrudes from the lower end of the shaft 4. A first shoulder 6 runs around the outer circumference of the pin, and a second shoulder 7 extends above it. A through-channel 8 extends vertically from the lower end of the pin 5 into the pipette housing 2.

[0077] An operating element 9 in the form of a sleeve-shaped control knob, closed at the top and open at the bottom, protrudes from the upper end of the pipette housing 2. A first adjustment element 10 in the form of a sleeve-shaped adjustment knob of an adjustment device 11 for adjusting the measuring stroke is arranged below the operating element 9 at the upper end of the pipette housing 2. The operating element 9 can be pressed almost completely vertically into the first adjustment element 10.

[0078] The lower end of a lifting rod 12 engages from above into the through-channel 8 of the pin 5. This rod extends upwards in the pipette housing 2 and is connected to the underside of the operating element 9.

[0079] The lifting rod 12 comprises an upper lifting rod part 13 and a lower lifting rod part 14. The upper lifting rod part 13 is inserted from above into a vertical first bore 15 which extends longitudinally through the entire lower lifting rod part 14, so that the upper lifting rod part 13 is displaceable in the lower lifting rod part 14.

[0080] A lower section of a tubular cage figs 16 is fixed in an upper section of a connecting element 17 in the form of a reducing sleeve (e.g. by screwing). The lower end of the cage figs 16 rests against a first projection 18 of the connecting element 17, which extends around the inner circumference. The lower lifting rod part 14 is fixed in the lower section of the connecting element 17 (e.g., by pressing in). The upper section of the connecting element 17 has larger inner and outer diameters than the lower section, and the connecting element 17 has a third shoulder 19 on the outer circumference between them.

[0081] The Kä fig 16 is limited at the top by a radially inwardly projecting, circumferential second projection 20. The upper lifting rod part 13 is connected by the cage fig 16 and the connecting element 17. The upper lifting rod part 13 has a circumferential bead 21, which is inserted into the cage fig 16 is arranged. A preloaded first coil spring 22 sits on the upper lifting rod part 13 between the bead 21 and the first projection 18. This presses the bead 21 against the second projection 20.

[0082] The top of the Kä figs 16 is a first stop element 23. Above this, a spindle nut 24 is arranged which is fixed in the pipette housing 2. In The spindle nut 24 engages a threaded spindle 25 having a second bore 26 through which the upper lifting rod part 13 is passed. The lower end face of the threaded spindle 25 forms a second stop element 27. The spindle nut 24 and the threaded spindle 25 are part of a first gear for adjusting the vertical position of the second stop element 27.

[0083] The first adjustment element 10 is fixedly connected to an adjustment sleeve 28. This is coupled to the threaded spindle 25 via a drive device 29 with axially extending grooves 30 on the inside of the adjustment sleeve 28 and radially outwardly projecting wings 31 engaging therein. The drive device 29 is coupled to the threaded spindle 25 in a rotationally fixed manner and is vertically displaceable relative to one another. Consequently, by rotating the first adjustment element 10, the axial position of the second stop element 27 in the pipette housing 2 can be adjusted without axially displacing the first adjustment element 10.

[0084] The first stop element 23 and the second stop element 27 together form a first stop device 32 which limits the upward displacement of the lifting rod 12.

[0085] The upper lifting rod part 13 is passed through the spindle nut 24 and is firmly connected to the operating element 9 so that it can be displaced vertically downwards by pressing the operating element 9.

[0086] The adjusting sleeve 28 is coupled at its lower end to a mechanical display device in the form of a mechanical counter via a pinion 33. Counter rollers 35 of the counter 34, arranged one above the other on a vertical axis of rotation, are visible from the outside through a first window 36.1 in a vertical side surface of the pipette housing 2.

[0087] The lower end face of the connecting element 17 is a third stop element 37.

[0088] A cup-shaped fourth stop element 38 is held in the pipette housing 2 below the connecting element 17. The fourth stop element 38 has a central through-hole 39 in its base 40, through which the lower lifting rod part 14 extends. The fourth stop element 38 is held in place by a compensating spring 41 acting on its upper edge and supported in the pipette housing 2, via a collar 42 extending around its outer circumference, on a fourth shoulder 43 in the pipette housing 2. The third stop element 37 and the fourth stop element 38 together form a second stop device 44, which limits the downward displacement of the lower lifting rod part 14.

[0089] A first spring device 45 in the form of a conical spring has a first engagement point in the pipette housing 2 on the upper side of the base 40 and a second engagement point on the third shoulder 19 of the connecting element 17 in order to press the cage when the operating button 9 is released. fig 16 to be moved upwards until the first anchor device 32 is struck.

[0090] The lifting rod 12 and the operating button 9 are part of a drive device 46 for a piston.

[0091] According to Fig. 4 and 5 A scanning device 47 is mounted on the pipette housing 2. This device has a scanning element 48 formed by the lower end of a slide 49. The slide 49 has a slide sleeve 50 guided on the shaft 4 at the bottom and a diaphragm 51 at the top. The slide sleeve 50 and the diaphragm 51 are connected to one another via a rod 52. The rod 52 is fixed at the bottom in a projection 53 protruding laterally from the slide sleeve 50. A web-like graduation mark 54 of the diaphragm 51 forms a marking 55 that can be set behind the lowest pre-decimal place and / or in front of the highest decimal place of the counter 34.

[0092] The aperture 51 is arranged on the inside of the pipette housing 2 outside in front of the counter 34, so that the graduation mark 54 is visible from the outside through the first window 36.1 of the pipette housing 2, which is covered by a transparent pane.

[0093] At the upper end of the aperture 51 is a flag 56 on which several different nominal volume indications 57, 58 are arranged one above the other. One nominal volume indication 57, 58 is visible from the outside through a second window 36.2 of the pipette housing 2, which is covered by a transparent pane.

[0094] The rod 52 of the slide 49 carries a radially projecting disc 59 which forms a fifth stop element 60.

[0095] The projection 53 is arranged through a shaft opening 61 at the lower end of a shaft 62 arranged laterally on the pipette housing 2. Within the shaft 62, the rod 52 is guided through a hole in a horizontal partition 63 of the pipette housing 2. The upper side of the partition 63 (in Fig. 4 (additionally entered) is a sixth stop element 64, which limits the downward displacement of the slide 49 by engaging the fifth stop element 60. The fifth stop element 60 and the sixth stop element 64 together form a third stop device 65.

[0096] A second spring device 66 in the form of a second helical spring 67 is supported at a third engagement point at the top on a holder 68 of the pipette housing 2 for the counter 34 and at a fourth engagement point at the bottom on a horizontal frame part 69 of the panel 51. The second helical spring 67 is pretensioned to hold the fifth stop element 60 in contact with the sixth stop element 64.

[0097] A pipette tip 70 has according to Fig. 2 and 3 a cylindrical piston running area 71. At the lower end of the cylindrical piston running area 71, there is a conical starting section 72. The tip opening 73 is arranged centrally at the lower end of the starting section 72.

[0098] The piston running area 71 is connected at the top to a conical transition area 74, which is followed by a cylindrical connecting area 75. The cylindrical connecting area 75 is connected to a collar 77 via an extension 76. The collar 77 has a slightly conical shape that widens upwards. On its inner circumference, it has a circumferential bead 78, which belongs to or forms a seating area 78.1.

[0099] In A piston 79 is arranged on the pipette tip 70. This piston has a conical piston section 80 that can be inserted into the cylindrical piston running area 71. At the upper end, the piston section 80 is sealed from the piston running area 71 by a sealing edge 81. At the bottom, the piston section 80 can be inserted into the conical initial section 72 of the pipette tip 70.

[0100] At the top, the piston section 80 is connected to a conical connecting section 82, which can be inserted into the transition area 74. A short piston rod 83 projects upwards from the transition area 74.

[0101] Pipette tips 70 with different nominal volumes have cylindrical piston running areas 71 and corresponding conical piston sections 80 with different cross-sections. They also differ in that the collar 77 has a different height relative to the seat area 78.1.

[0102] At the upper end of the collar 77 is the attachment opening 84 of the pipette tip 70.

[0103] According to Fig. 2 and 4 until 7 A pipette 1 with the pin 5 is inserted into the attachment opening 84 of a pipette tip 70 with an integrated piston 79. When the pipette tip 70 is attached to the pin 5, an inner step 76.1 strikes within the collar 77 (cf. Fig. 9 ) or the upper edge of the collar 77 (cf. Fig. 10 ) onto the second shoulder 7. In both designs, the bead 78 below the first shoulder 6 rests equally against the pin 5 under prestress, so that the pipette tip 70 is securely clamped onto the pin 5. The bead 78 and thus the seating area 78.1 of both designs rests sealingly against the same clamping zone 5.1 of the pin 5.

[0104] When the upper edge of the collar 77 hits the second shoulder 7, the slider 49 is not moved and the display of the mechanical counter 34 remains unchanged. This is the case when attaching the 100 µl pipette tip, which is inserted into the Figuren 2 , 5 , 7 and 10 The display is the same as in Fig. 8 , which shows the pipette without the pipette tip 70 attached. The graduation mark 54 shows the user the lowest digit before the decimal point or the highest digit after the decimal point.

[0105] When the inner step 76.1 hits the second shoulder 7, the upper edge of the collar 77 projecting beyond the inner step 76.1 hits the lower end of the slide 49 and moves it upwards against the action of the second coil spring 67. In doing so, the aperture 51 is displaced so that the graduation mark 54 is moved into a different position between two counter rollers 35 of the counter 34. This is the case when attaching the 10 µl pipette tip 1, which is in Fig. 4 , 6 and 9 is shown. The displacement of the graduation mark 54 depends on the height of the collar 77. Depending on the nominal volume of the pipette tip 70, the graduation mark 54 is thus set next to a specific position on the counter 34.

[0106] Additionally, the user is shown the respective nominal volume information 57, 58 for the attached pipette tip 70 in the second window 36.2. Pipetting with pipette 1 is explained below.

[0107] The piston rod 83 is connected to the lifting rod 12 by pressing the operating element 9 until the second stop device 44 hits. In this case, the piston rod 83 is clamped into the first bore 15 of the lifting rod 12. This is shown in Fig. 2 shown.

[0108] Thereafter, with the control element 9 pressed in, the lower end of the pipette tip 70 can be immersed in a liquid in a container. When the control element 9 is released, the lifting rod 12 and thus the piston 79 are displaced upward by the first spring device 45 until it strikes the first stop device 32, and liquid is sucked into the pipette tip 70.

[0109] To dispense the collected liquid volume, the lower end of the pipette tip 70 is inserted into another container, and the liquid is dispensed by pressing the operating element 9 until it hits the second stop device 44. The piston 79 is thereby moved to its lowest position in the pipette tip 70, and the liquid volume is displaced through the tip opening 73 into the container.

[0110] According to Fig. 3 To release the pipette tip 70, the operating element 9 is pressed further in so that the first coil spring 22 compresses and the upper lifting rod part 13 pushes the piston rod 83 out of the first bore 15.

[0111] In a pipette 1 designed as an air-cushion pipette, the lifting rod 12 is coupled to a piston, which can be displaced in a cylinder arranged in the pipette housing 2 by actuating the operating element 9. The cylinder is connected via a channel to a hole in the lower end of the pin 5.

[0112] As with the positive displacement pipette, the sensing device 47 can be designed such that it has a sensing element 48 at the lower end of a slide 49, which has a slide sleeve 50 guided on the shaft 4. The slide 49 is coupled at the top to a marking 55 for setting laterally next to a counter roller 35 of a counter 34 and, if necessary, to a flag 56 for displaying various nominal volume values ​​57, 58 in a window.

[0113] The slider 49 can also be used to eject the pipette tip 70. For this purpose, the slider 49 is Fig. 9 coupled to an ejection button 85 that protrudes outward from the pipette housing 2. In principle, the ejection button 85 can be rigidly connected to the slide 49. However, this has the consequence that the position of the ejection button 85 depends on the height of the collar 77 of the respective attached pipette tip 70.

[0114] In the examples of Fig. 11 bis 13 This is avoided by providing a fourth stop device 86 with a seventh stop element 87 on the ejection button 85 and an eighth stop element 88 on the pipette housing 2, which limit an upward displacement of the ejection button 85. In addition, a transmission device 89 is provided between the ejection button 85 and the slide 49, which, when the slide 49 is displaced upward, does not displace the ejection button 85 upwards and, when the ejection button 85 is displaced downwards, displaces the slide 49 downwards.

[0115] According to Fig. 11 the transmission device 89 comprises a fourth spring device 90 between the release button 85 and the rod 52 of the slider 49, which is designed as a third coil spring 91.

[0116] The fourth spring device 90 is pre-tensioned, so that when the ejector button 85 is not pressed in, the fourth stop device 86 is effective. When a pipette tip 70 is attached, the slide 49 is displaced upwards and the fourth spring device 90 is compressed. The ejector button 85 remains in its upper stop position. When the ejector button 85 is actuated, the fourth spring device 90 is initially further compressed. The ejector button 85 then presses on the rod 52 of the slide 49, causing the latter to strip the pipette tip 70 from the pin 5.

[0117] According to Fig. 12 and 13The transmission device 89 comprises a locking device 92 arranged between the release button 85 and the slide 49. This locking device is a gear 93 rotatably mounted on the release button 85, which has a freewheel 94. The rod 52 has a toothed strip 95 on one side, which engages with the gear 93.

[0118] When the ejector button 85 is not actuated, the fourth stop device 86 is activated due to a fifth spring device 96 acting on it. When a pipette tip 70 is attached, the slider 49 is displaced upward, allowing the gear 93 to rotate freely. Only when the ejector button 85 is actuated does the free rotation of the gear 93 stop, and the rod 52 is also moved downward. As a result, the slider 49 pushes the pipette tip 70 off the pin 5.

[0119] According to Fig. 14 Displacement of the ejector button 85 when attaching the pipette tip 70 is prevented by the fact that an ejector slide 97 is provided in addition to the slide 49. The slide 49 has an inner slide sleeve 98 guided on the shaft at its lower end, and the ejector slide 97 has an outer slide sleeve 99 guided on the inner slide sleeve 98 at its lower end.

[0120] The pipette tip 70 has two concentric circumferential steps 100, 101 at the upper edge, with the inner step 100 projecting further upwards in the vertical direction than the outer step 101.

[0121] When the pipette tip 70 is attached, the inner step 100 actuates the slide 49, thereby setting the graduation mark 54 on the mechanical counter 34. The ejector slide 97 is not actuated by the outer step 101. When the ejector button 85 is pressed, the lower end of the ejector slide 97 strikes the outer step 101 and pushes the pipette tip 70 off the pin 5.

[0122] According to Fig. 15 bis 17 A pipette 1 designed as a positive displacement pipette comprises a pipette housing 2 with an operating element 9 designed as a vertically pivotable operating lever 102 on a vertical side surface and a first adjustment element 10 designed as a rotary knob 103 for setting a volume at the upper end. A positive displacement pipette tip 70 can be clamped onto the pin 5 at the bottom.

[0123] By pressing the operating lever 102 downwards once or repeatedly, a set volume can be drawn into the pipette tip 70. A spring is arranged in the pipette housing 2; this spring is tensioned by pressing the operating lever 102 downwards and pivots the operating lever 102 upwards after the spring is released. The length of the movement of the operating lever 102 and / or the number of times it is actuated depends on the set volume. Furthermore, by pivoting the operating lever 102 downwards once or repeatedly, the drawn-up liquid can be dispensed from the pipette tip 70. The actuation or the number of actuations depends, in turn, on the set volume.

[0124] In order to control both the suction of liquid into the pipette tip 70 and the ejection of liquid from the pipette tip 70 by pivoting the operating lever 102 downward, the drive device of the pipette 1 has a switching device which reverses the direction of displacement of the piston 79 by actuating the operating lever 102 after the set volume has been sucked into the pipette tip 70. Consequently, further actuation of the operating lever 102 causes the ejection of the aspirated liquid from the pipette tip 70. List of reference symbols

[0125] 1 pipette 2 pipette body 3 handle 4 shaft 5 pin 5.1 clamping zone 6 first shoulder 7 second shoulder 8 through-channel 9 operating element 10 first adjusting element 11 adjusting device 12 lifting rod 13 upper lifting rod part 14 lower lifting rod part 15 first bore 16 cage 17 connecting element 18 first projection 19 third shoulder 20 second projection 21 bead 22 first coil spring 23 first stop element 24 spindle nut 25 threaded spindle 26 second bore 27 second stop element 28 adjusting sleeve 29 driving device 30 groove 31 vane 32 first stop device 33 pinion 34 mechanical counter 35 counter roller 36.1 first window 36.2Second window 37Third stop element 38Fourth stop element 39Through hole 40Base 41Compensating spring 42Collar 43Fourth shoulder 44Second stop device 45First spring device 46Drive device 47Sensing device 48Sensing element 49Slide 50Slide sleeve 51Aperture 52Rod 53Protrusion 54Graduation mark 55Marking 56Flag 57Nominal volume indication 58Nominal volume indication 59Disc 60Fifth stop element 61Shaft opening 62Shaft 63Partition 64Sixth stop element 65Third stop device 66Second spring device 67Second coil spring 68Holder 69Frame part 70Pipette tip 71Piston running area 72Conical Initial section 73Tip opening 74Conical transition area 75Cylindrical connection area 76Extension 76.1Inner step 77Collar 78Bead 78.1Seat area 79Piston 80Conical piston section 81Sealing edge 82Conical connecting section 83Piston rod 84Sliding opening 85Ejector button 86Fourth stop device 87Seventh stop element 88Eighth stop element 89Transmission device 90Fourth spring device 91Third coil spring 92Locking device 93Gear 94Freewheel 95Toothed strip 96Fifth spring device 97Ejector slide 98Inner slide sleeve 99Outer slide sleeve 100Inner step 101Outer step 102Operating lever 103Rotary knob.

Claims

1. A pipette for use with a pipette tip of a pipette tip line comprising pipette tips of different types, comprising: • a rod-shaped pipette housing (2), • a neck (5) at the bottom end of the pipette housing (2) for clamping on a pipette tip (70) with a collar (77) having a mounting opening (84) at its upper end, • a drive apparatus (46) comprising a drive element (12) for displacing a displacement element (79) for drawing in liquid samples into the pipette tip (70) and ejecting the samples from the pipette tip (70), and an operating element (9) projecting from the pipette housing (2) and displaceable relative to the pipette housing, • a scanning apparatus (47) having a scanning element (48) arranged next to the neck (5) and displaceable in the longitudinal direction of the neck (5) relative to the pipette housing for being displaced by the collar (77) of a pipette tip (70) when clamping the pipette tip (70) onto the neck (5), • a mechanical display apparatus (34) coupled to the scanning apparatus (47), wherein the scanning apparatus (47) is designed so that it adjusts a display of the display apparatus (34) which depends on the position of the scanning element (48) relative to the pipette housing (2), for adjusting a display depending on the type of pipette tip (70) by clamping onto the neck (5) a pipette tip (70) with a height of the collar (77) characteristic of the type of pipette tip (70), characterized by • a first stop apparatus (32) with a first stop element (23) on the drive apparatus (46) and a second stop element (27) on the pipette housing (2) that can be brought into contact against each other by displacing the drive element (12) in a first direction, • a second stop apparatus (44) with a third stop element (37) on the drive apparatus and a fourth stop element on the pipette housing (2) that can be brought into contact against each other by displacing the drive element (12) in a second direction that is opposite the first direction in order to define a measuring stroke of the drive apparatus (46) together with the first stop apparatus (32), • an adjusting apparatus (11) with a first adjusting element (10) mounted on the pipette housing (2), and a second adjusting element on the first or second stop apparatus (32, 44) for adjusting the measuring stroke by adjusting the first adjusting element (10), • a mechanical counter (34) coupled to the adjusting apparatus (11) for displaying the adjustment of the adjusting apparatus (11), • wherein the scanning apparatus (47) is coupled to a mechanical range adjusting apparatus on the counter (34) that is designed so that it adjusts a count range of the counter (34) which depends on the position of the scanning element (48) relative to the pipette housing.

2. The pipette according to claim 1, wherein the display depending on the type of pipette tip (70) comprises or is a volume display.

3. The pipette according to claim 1 or 2, wherein the scanning apparatus (47) has a pusher (49) displaceably guided on the pipette housing (2) in a vertical direction that has the scanning element (48) on the lower pusher end, and whose upper pusher end is coupled to the display apparatus (34).

4. The pipette according to claim 3, wherein the pusher (49) bears different nominal volume data (57, 58) one over one another in a vertical direction on an outer side, or different other data characterizing the type of pipette tip (70), and the pipette housing (2) has a window (36) in the displacement region of the nominal volume data or the other data of the pusher (49), through which only one complete nominal volume datum (57, 58) or one complete other datum on the pusher (49) is visible from the outside.

5. The pipette according to one of claims 3 and 4, wherein the range adjusting apparatus comprises a mark (55) on the upper pusher end arranged on the outside in front of the counter (34), whereby the pusher (49) can be displaced upward to a varying extent when clamping pipette tips (70) with collars (77) of different heights on the neck (5) in order to position the mark (55) to display different count ranges laterally next to or between different counter rollers (35) of the counter (34).

6. The pipette according to one of claims 3 to 5, wherein the scanning element (48) is formed on the lower pusher end of a pusher sleeve (50) that can be shifted in a vertical direction along a shaft (4) of the pipette housing (2) which has the neck (5) at the lower end.

7. The pipette according to claim 5 or 6, wherein the mark is a bar-like graduation mark (54) of an aperture (51) connected to the upper pusher end.

8. The pipette according to one of claims 1 to 7, comprising a first spring apparatus (45) with a first contact point on the pipette housing (2), and a second contact point on the drive apparatus (46) in order to displace the drive element (12) in the first direction when the operating element (9) is released until the first stop element (23) comes into contact with the second stop element (27).

9. The pipette according to one of claims 3 to 8 that has a third stop apparatus (65) with a fifth stop element (60) on the pusher (49), and a sixth stop element (64) on the pipette housing (2), and a second spring apparatus (66) with a third contact point on the pipette housing (2), and a fourth contact point on the pusher (49) in order to stress the pusher (49) downward and place the fifth stop element (60) on the sixth stop element (64) when a pipette tip (70) is not mounted on the neck (5).

10. The pipette according to one of claims 3 to 9, wherein the pusher (49) is connected at the top to an ejection button (85) projecting from the upper end of the pipette housing (2), by the actuation of which the pusher (49) can be displaced downward in order to slip a pipette tip (70) from the neck (5) by the lower pusher end.

11. The pipette according to claim 3 and 10 that has a fourth stop apparatus (86) with a seventh stop element (87) on the ejection button (85), and an eighth stop element (88) on the pipette housing (2) that are designed to limit the displacement of the ejection button (85) upward, and that has a transmission apparatus (89) between the ejection button (85) and pusher (49) which is designed to prevent the ejection button (85) from being displaced upward when the pusher (49) is displaced upward, and to displace the pusher (49) concomitantly downward when the ejection button (85) is displaced downward.

12. The pipette according to claim 3 and 11, (i.) wherein the transmission apparatus (89) is a fourth spring apparatus (90) that has a fifth contact point on the ejection button (85) and a sixth contact point on the pusher (49), whereby when the pusher (49) is displaced upward, the fourth spring apparatus (90) is compressed, and when the ejection button (85) is displaced downward, initially the fourth spring apparatus (90) is compressed, and then the ejection button (85) entrains the pusher (49), or (ii.) wherein the transmission apparatus (89) is a locking device (92) arranged between the ejection button (85) and pusher (49) that allows an upward displacement of the pusher (49) relative to the ejection button (85) and prevents a downward displacement of the ejection button (85) relative to the pusher (49).

13. The pipette according to one of claims 3 to 9 that, in addition to the pusher (49), has an ejection pusher (97) guided in a vertical direction on the pipette housing (2) that is connected to the ejection button (85) at the upper end, and whose lower end is arranged radially offset to the lower end of the pusher (49) next to the neck, wherein (i.) the lower ends of the pusher (49) and ejection pusher (97) are arranged at the same height so that by clamping a pipette tip (70) with two peripheral steps (100, 101) on the upper end onto the neck (5), the pusher (49) is displaceable by the inner step (100), and the ejection pusher (97) is not displaceable by the outer step (101), and by actuating the ejection button (85), the lower end of the ejection pusher (97) can be pressed against the outer step (101) of the pipette tip (70) in order to slip it off of the neck (5), or (ii) the lower end of the pusher (49) is arranged lower than the lower end of the ejection pusher (97) so that by clamping a pipette tip (70) with a flat upper edge onto the neck (5), the pusher (49) is upwardly displaceable, and the ejection pusher (97) is not upwardly displaceable, and by actuating the ejection button (85), the ejection pusher (97) can be pressed against the upper end of the pipette tip (70), and the pipette tip (70) can be slipped off of the attachment (5).

14. The pipette according to one of claims 1 to 13, whose attachment (5) has a peripheral shoulder (7) on the outer circumference at a distance from the lower end so that a pipette tip (70) can be shoved on with a peripheral inner step (76) projecting radially inward on the inner circumference of the collar (77) until the inner step (76) contacts the shoulder (7).

15. A pipette tip line for use with a pipette comprising at least two pipette tips (70) of different types, wherein each pipette tip (70) has a tip opening (73) at the lower end, a collar (77) having a mounting opening (84) with a height at the upper end characteristic of the type of pipette tip (70), and a seat region on the inner circumference of the collar (77) for clamping onto a neck (5) with a specific contour of a pipette (1), characterized in that pipette tips (70) of different types can be clamped by their seat region (78.1) onto the same clamping zone (5.1) of the neck (5) so that they project upward with their collar (77) on the neck (5) at different heights.

16. The pipette tip line according to claim 15, comprising at least two pipette tips (70) which differ with respect to one or more of the following features: nominal volume, shape, dimensions, material, without or with coating, without or with surface treatment, tube without or with an inserted filter, electrically insulating or electrically conductive, and degree of purity.

17. The pipette tip line according to claim 15 or 16, wherein the difference in height with which the collar (77) of pipette tips (70) with different nominal volumes projects upward on the same neck (5) is the single or integral multiple of the height of a counter roller (35) of a mechanical counter (34).

18. The pipette tip line according to one of claims 15 to 17, wherein the difference in height is the single or integral multiple of 1 to 7 mm, preferably 3 to 5 mm, preferably 4.5 mm.

19. The pipette tip line according to one of claims 15 to 18, wherein above the seat region (78.1), the collar (77) has an upper edge or a circumferential inner step (76.1) projecting radially inward on the inner circumference, and the collar (77) has an expanded section above the inner step (76.1) so that the pipette tip (70) can be shoved onto an attachment (5) until the upper edge or the inner step (76.1) contacts a shoulder (7) of said attachment.

20. The pipette tip line according to one of claims 15 to 19, wherein each pipette tip (70) has two concentric peripheral steps (100, 101) on the upper edge, wherein one step (100) projects further upward than the other step (101) relative to the lower tip opening (73).

21. The pipette tip line according to one of claims 15 to 20 that has a cylindrical plunger travel region (71) between the tip opening (73) and mounting opening (84), and a plunger (79) with a plunger rod (83) at the upper end for being clamped in a hole in a stroke rod (12) of a pipette (1) formed as a positive displacement pipette.

22. A pipette system comprising a pipette according to one of claims 1 to 14, and at least one pipette tip (70) from the pipette tip line according to one of claims 15 to 21.