EP2263800A2 - Pipette with pipette tip ejector - Google Patents

Abstract

A pipetting device comprises a base body; attachment(s) (34) protruding from the base body mounted axially movably on the base body to mount a pipette tip, a spring (24) where the attachment is supported on the base; a stop associated with the attachment; and an ejection device to release the pipette tip from the attachment that has throw-off device associated with the attachment. A pipetting device comprises a base body, attachment(s) protruding from the base body mounted axially movably on the base body to mount a pipette tip, a spring where the attachment is supported on the base, a stop associated with the attachment beyond where the attachment protrudes axially when it is not loaded toward the spring, and an ejection device to release the pipette tip from the attachment that has throw-off device associated with the attachment. The attachment and throw-off device are movable relative to one another and comprise a drive device cooperating with the throw-off device and/or the attachment for the relative movement of the throw-off device and attachment.

Description

The invention relates to a pipetting device with at least one approach for attaching a pipette tip and a discharge device for releasing a pipette tip of the approach.

Pipetting devices are used in particular in the laboratory for dosing liquids. These are picked up in pipette tips through a tip opening and dispensed. In the case of air cushion pipettes, a displacement device for a gas is integrated in the pipetting device and connected in a communicating manner with the pipette tip through the approach. By means of the displacement means an air cushion is displaced, so that liquid is sucked into the pipette tip and ejected therefrom. The displacement device is usually a cylinder with a piston displaceable therein.

The pipette tips are releasably connected to the neck so that they can be replaced with a fresh tip after use. As a result, contamination can be avoided at subsequent dosages. Single-use pipette tips are available inexpensively from plastic.

The approach for attaching pipette tips is often a cylindrical or conical projection with respect to a base body or a housing, on which a pipette tip with a mating Aufstecköffnung or recording is clamped. This can be done without touching the pipette tip by pressing the projection into the plug-in opening of the pipette tip provided in a holder.

In order to avoid contamination of the users, pipetting devices have a discharge device with a drive device and an ejector. By operating the drive means the ejector is displaced so that it dissolves the Pipettcnspitze of the approach, without having to be handled by the user. In many cases, the drive device has a mechanism which must be manually operated by means of an actuating button to release the pipette tip from the neck. Also possible are drive devices with an electric motor drive. The release of the pipette tip from the neck can require considerable effort, especially with pipette tips firmly clamped onto the neck. Already in single-channel systems, i. Pipetting devices having a single approach to a single pipette tip can make it difficult or impossible to drop the pipette tip from the neck. Particularly high expenditure of force can be required in multi-channel pipetting systems, which have several parallel approaches for attaching pipette tips, due to multiple peak ejection forces.

From the EP 0 992 288 A2 is a pipetting system with an axially movable ejector for releasing a pipette tip of a neck, a drive device for driving the axial movements of the ejector and a axial drive movement of the drive device in an axial movement of the ejector transmitting traction, pressure medium or linkage known. The force exerted by the ejector on the pipette tip exceeds the force exerted by the user, thereby facilitating ejection.

From the US 4,187,724 For example, there is known a pipetting device having a pipette tip fitting approach which is a shaft protruding portion of a shaft which is rotatable in the shaft. The pipetting device has a rotary drive for the shaft. Furthermore, the end facing the approach of the shaft is designed as a cam surface. The pipette tip points at Aufsteckende also a curved surface. By actuating a slider, the shaft is set in rotary motion whereby a pipette tip placed on the tab is rotated with its cam surface against the cam surface of the shaft so that as the shaft rotates, the lip rotates with respect to the pipette tip and the pipette tip is released.

In these pipetting devices, the actuation of the discharge device still requires a great deal of effort. In addition, the pipette tips are special parts due to the curved surface.

Furthermore, pipetting devices and associated pipette tips are known which have an internal shoulder to limit changes in the Aufsteckkraft and, accordingly, the force required for the operation of the discharge device. These pipetting systems have the disadvantage that the use of the pipette tips is often limited to the associated pipetting devices and vice versa. The user is limited by this.

Based on this, the present invention seeks to provide a pipetting available, which reduces the force required for the operation of the discharge device.

The object is achieved by a pipetting device with the features of claim 1. Advantageous embodiments of the pipetting device are specified in the subclaims.

• einen Grundkörper,
• mindestens einen vom Grundkörper vorstehenden, axial beweglich am Grundkörper gelagerten Ansatz zum Aufsetzen einer Pipettenspitze,
• eine Feder, über die der Ansatz am Grundkörper abgestützt ist,
• einen dem Ansatz zugeordneten Anschlag, über den der Ansatz axial hinaussteht, wenn er nicht zur Feder hin belastet ist, und
• eine Abwurfeinrichtung zum Lösen der Pipettenspitze von dem Ansatz, die einen dem Ansatz zugeordneten Abwerfer aufweist, wobei Ansatz und Abwerfer relativ zueinander beweglich sind.

The pipetting device according to the invention has

• a basic body,
• at least one projection projecting from the main body and axially movably mounted on the main body for fitting a pipette tip,
• a spring, via which the attachment is supported on the base body,
• a stop associated with the approach over which the projection projects axially when it is not loaded to the spring, and
• a release device for releasing the pipette tip from the lug, which has an ejector associated with the lug, wherein lug and ejector are movable relative to each other.

In the pipetting device according to the invention, a pipette tip is plugged by axial insertion of the approach in the plug-in opening. The Aufsteckkraft is introduced into the spring. If the slip force exceeds a certain value, the spring is elastically deformed until the pipette tip clamped on the shoulder abuts against the stop. As soon as the pipette tip touches the stopper, it can no longer be pushed onto the attachment. As a result, the attachment force of the pipette tip is limited. The Aufsteckkraft is determined by the spring characteristic of the spring or any existing bias of the spring. The spring is designed and optionally biased, that the pipette tip exactly when it sits with the desired Aufsteckkraft on the approach, abuts the stop. The Aufsteckkraft is set so that the pipette tip sits securely on the approach or seals. Since a precise defined Aufsteckkraft is achieved, it is possible to limit the Aufsteckkraft to a low value, in which the required safety of the seat and the seal is just given. Thus, the Aufsteckkraft can be significantly reduced compared to conventional pipetting in which due to the uncertainties when plugging regularly excessive Aufsteckkraft is expended. Accordingly, in the pipetting device according to the invention, the force required for the actuation of the ejection device is reduced. In manually operable ejection devices are by Reduction of operating forces reduces the tendon and muscle strain of the user. Electromotive operated ejection devices can handle low power engines. According to one embodiment, the spring is so designed and / or biased that the approach of a defined Aufsteckkraft, which can be applied by attaching a pipette tip on the approach, in such a way towards the stop is displaced that the pipette tip abuts the stop.

To release the pipette tip of the approach approach and ejector are relative to each other axially and / or rotatably. The invention relates to embodiments in which the ejector is arranged stationarily with respect to the pipetting device and the drive device moves exclusively the approach. Furthermore, the invention involves embodiments in which the drive means moves the ejector and the approach. In preferred embodiments, the approach with respect to the pipetting device is stationary and the drive means is operatively connected only to the ejector, so that only the ejector is movable by means of the drive means.

According to one embodiment, the discharge device has a drive device operatively connected to the ejector and / or the attachment for relatively moving the ejector and the attachment.

According to one embodiment, the approach is supported directly on the spring. The connection of the approach with a permanently connected to the body Verdrängungscinrichtung can be done by means of a flexible connection, for example by means of a flexible hose or a telescopic pipe connection. According to one embodiment, the approach is firmly connected to a displacement device - for example with a cylinder of a relative to the main body axially displaceable piston-cylinder device - connected. The displacer is then displaced with the neck. The displacement of the displacement device can from the Drive device for the displacement device can be compensated. According to one embodiment, the cylinder is supported by the spring on the base body, so that the approach is indirectly cushioned over the cylinder.

According to one embodiment, the spring is an extended in the axial direction of the neck coil spring. The coil spring is preferably coaxial with the extension. The displacement device or drive device for the displacement device can advantageously be passed through the coil spring.

The pipetting device can be executed with a non-preloaded spring. Then the spring is compressed according to the increase in Aufsteckkraft when attaching the approach to the pipette tip. By designing the spring and the way to the concerns of the pipette tip on the stopper, it is possible to determine the Aufsteckkraft exactly. According to one embodiment, the spring has a spring bias. As a result, it comes only to an axial displacement of the approach when the Aufsteckkraft exceeds the force to bias the spring. As a result, the Autstcckkraft required for reaching the stop is defined. Furthermore, this favors particularly compact spring arrangements and short displacement paths of the approach.

According to one embodiment, the stop, which is hit by the pipette tip when plugged in, is firmly connected to the base body. According to another embodiment, the stop is axially movable with respect to the approach and a fixedly connected to the body boundary for the axial movement of the stop to the body out there.

According to one embodiment, the stop is formed on the ejector. In one embodiment of the ejector as a neck coaxial sleeve the stop is formed by the approach end facing the sleeve.

The approach can be fixed in various ways in its axial starting position for receiving a pipette tip, for example by connecting the approach with the spring. The initial position of the approach is then defined by the initial position of the spring unloaded by the approach. According to one embodiment, the approach is supported in the direction away from the spring at a further stop, against which it is pressed by the spring. As a result, the starting position is precisely determined. In addition, no connection between approach and spring is required.

According to one embodiment, the spring is exchangeable and / or there is a device for adjusting the spring preload. This makes it possible to adapt the attachment and ejection forces to differently shaped or sized pipette tips. The range of application of the pipetting device is thereby increased.

According to one embodiment, the drive device can be actuated against the action of a further spring supported on the one hand on a movable part of the drive device and on the other hand on the main body. As a result, the drive device automatically returns to its original position after actuation. For a defined starting position, for example, there is a fixed limitation with regard to the basic body for the movement of the ejector or the drive device. This can also be the limit for the axial movement of the stop to the main body out.

According to one embodiment, the base body on a support or frame. According to one embodiment, the main body has a housing, optionally with a carrier or frame contained therein.

According to one embodiment, the pipetting device is a hand-held device and / or a stationary device and / or an electrically driven device and / or a (semi-) automaton. In handheld versions, the pipetting device is manually guided to the location of the sample receptacles and sample dispensers, and the liquid intake and dispensing and actuation of the dispensing device are manually controlled. The drive devices for the displacement device and / or the ejector are designed mechanically and / or electromechanically. The latter also applies to the execution of the pipetting as a stationary device. When the pipetting device is designed as a (semi) automaton, all functions or a part of the functions of the pipetting devices (picking up and dispensing liquid, moving the pipetting devices into positions for picking up and dispensing liquid or pipette tips, picking up and dispensing pipette tips) are automatically carried out ,

According to one embodiment, the pipetting device has a series of parallel lugs for receiving pipette tips. It is a multi-channel pipetting system. Due to the multiplied peak discharge forces, the use of the invention is particularly advantageous here.

According to one embodiment, each approach is supported on the main body via a separate spring.

According to one embodiment, the approaches associated with a common ejector.

• eine Verdrängungseinrichtung mit einer Verdrängungskammer mit einer verlagerbaren Begrenzung, einem Ansatz zum Verbinden mit einer Pipettenspitze und einem Verbindungskanal zwischen der Verdrängungskammer und dem freien Ende des Ansatzes,
• eine Antriebseinrichtung zum Antreiben der verlagerbaren Begrenzung der Verdrängungseinrichtung mit einem Antriebsorgan, das eine lösbare Wirkverbindung mit der verlagerbaren Begrenzung hat, und
• einer Bajonettverbindung zwischen der Antriebseinrichtung und der Verdrängungseinrichtung, die unter Herstellung der Wirkverbindung zwischen Antriebsorgan und verlagerbarer Begrenzung herstellbar und unter Lösung der Wirkverbindung zwischen Antriebsorgan und verlagerbarer Begrenzung lösbar ist.

According to one embodiment, the pipetting device according to the invention

• a displacement device having a displacement chamber with a displaceable boundary, a projection for connection to a pipette tip and a connection channel between the displacement chamber and the free end of the projection,
• a drive device for driving the displaceable boundary of the displacement device with a drive member which has a detachable operative connection with the displaceable boundary, and
• a bayonet connection between the drive device and the displacement device, which can be produced by establishing the operative connection between the drive member and displaceable boundary and releasing the active connection between the drive member and displaceable boundary.

The displacement device and the drive device for driving the displaceable boundary of the pipetting device can be connected to each other in a simple manner by mating along a longitudinal axis of the bayonet connection and rotating about the longitudinal axis of the bayonet connection or in a reverse manner separable from each other. When making the bayonet connection, the operative connection between the drive member and displaceable boundary is at the same time produced, without requiring special further actions for this purpose. When releasing the bayonet connection, the active compound is released without any special further actions. The invention enables a particularly simple, fast and secure connection and disconnection of the displacement device and the drive device for driving the displaceable boundary, for example during assembly, before autoclaving or other cleaning of the lower part, before replacing the lower part for purposes of changing the working area, repair etc. The bayonet connection is special störungsunanfallig. These advantages are particularly useful in manual and automatic connection and disconnection of displacing means and driving means for driving the displaceable boundary. The latter, for example, in an automatic assembly or a workstation with automatic tool change.

The drive device for driving the displaceable boundary can be designed in various ways. It has technical means to shift the drive member so that this shifts the movable limit of the displacement device. For this purpose, the drive member carries e.g. a linear motion. Accordingly, the drive device for driving the displaceable boundary on a linear drive. These are e.g. to a directly actuated by key operation stroke rod or to a linearly displaceable via an electric drive motor and a gear lift rod. Also considered is a pneumatically or hydraulically operated pressure medium cylinder as a drive for the lifting rod, which is actuated by a pneumatic or hydraulic control and a pressure medium reservoir. If the drive member does not perform a linear movement, but a spatial feed movement, the drive means for driving the movable boundary on a corresponding drive.

Preferably, the drive device for driving the movable boundary on a housing in which drive and drive member are arranged.

According to one embodiment, the drive member is a displaceable parallel to the longitudinal axis of the bayonet connection lifting rod of the drive means and has the Verdrungsungumung connected to the boundary, directed transversely to the lifting rod contact surface, which is pressed by a lifting spring against the end of the lifting rod. In this embodiment, the operative connection between the drive member and displaceable boundary produced automatically when making the bayonet connection and automatically released when dissolving the bayonet connection.

According to one embodiment, the contact surface is formed on a pressure piece connected via a rod to the displaceable boundary and the lifting spring is designed as a helical spring which is supported at one end on the pressure piece and others on the displacement chamber.

The bayonet connection can be configured in various ways. Included in particular by the invention is the configuration of the drive device as a male part and the displacement device as a female part of the bayonet connection and vice versa. According to one embodiment, the drive device has a cylindrical receptacle which has an opening at one end, through which the cylindrical receptacle is accessible in the axial direction from the outside, which has at least one axially directed longitudinal groove which is connected to an annular groove directed in the circumferential direction of the cylindrical receptacle is, and the Verdrängungscinrichtung on a cylindrical portion at least one outwardly projecting projection, wherein the cylindrical portion in the axial direction of the cylindrical receptacle through the opening in the receptacle and with the projection in the longitudinal groove inserted and screwed with the projection in the annular groove is. In this embodiment, the drive means is the female and the displacement means the male part.

According to one embodiment, the annular groove at a distance from the longitudinal groove on a in the axial direction of the receptacle extending boundary wall, to which the projection is rotatable. Reaching the limit indicates to the user that the bayonet connection is made.

According to one embodiment, the annular groove is connected at a distance from the longitudinal groove with a parallel thereto extending Längsnutabschnitt, which ends at a distance from the opening. By engaging the projection in the Längsnutabschnitt a backup of the bayonet connection is effected.

According to one embodiment, the annular groove has a ramp-like boundary wall whose distance from the opening increases with increasing distance from the longitudinal groove. The ramp-like course of the boundary wall facilitates the finding of the connection position and the separation of the displacement device from the drive device.

According to one embodiment, the longitudinal groove, the annular groove and optionally the Längsnutabschnitt is formed in a cylindrical coupling piece which forms the receptacle of the drive means and is fixed in this. This facilitates manufacture, assembly and disassembly.

According to one embodiment, the drive device has a spring which presses against the displacement device connected to the drive device via the bayonet connection. This will secure the bayonet connection.

According to one embodiment, the spring is arranged on a further opening of the receptacle, which is opposite to the opening for the axial insertion of the displacement device. Through the opening displacement and spring act on each other. According to a further embodiment, the spring is a helical spring, which is supported on an inner end face of the coupling piece.

According to one embodiment, the longitudinal groove and / or annular groove and / or the Längsnutabschnitt open to the other opening.

According to one embodiment, the displacement is a piston-cylinder device with a cylinder and a piston displaceable therein and the piston has the displaceable boundary. Other displacement means are also included in the invention, for example a displacement chamber with a displaceable boundary forming elastic wall. A piston-cylinder device is e.g. operated by a linear drive device. A corresponding actuation is possible with a displacement chamber with an elastic wall. The latter can also be controlled via a drive device with a spatial drive movement. For example, it is possible to externally control the elastic wall by the action of a hydraulic or pneumatic pressure means.

According to one embodiment, the approach is aligned coaxially to the longitudinal axis of the bayonet connection. According to a further embodiment, the approach is firmly connected to the displacement device.

According to one embodiment, the pipetting device has a discharge device for ejecting a pipette tip from the attachment, which has a discharge drive arranged on the drive device, an ejector arranged on the displacement device and a directed in the direction of the longitudinal axis of the bayonet connection, detachable axial clamping connection between discharge drive and ejector. The clamping connection can be produced simultaneously with the production of the bayonet connection with the phase of the axial collapse of the displacement device and the drive device and can be released in the reverse direction.

According to one embodiment, the ejector drive a projecting from the drive device parallel to the bayonet release rod and the ejector to a neck parallel, axial bore, with which the discharge rod is press-connected.

According to one embodiment, the ejector is guided on the displacement unit.

According to one embodiment, the ejector is a sleeve guided on the displacement device.

According to one embodiment, the pipetting device is a hand-held device and / or a stationary device and / or an electrically driven device and / or a (Flalb) Autozmat. In embodiments as a hand-held device, the pipetting device is manually guided to the location of the sample receptacles and sample dispensing, and the picking and dispensing of liquid and the actuation of the ejection device are controlled manually. The drive devices for the displacement device and / or the ejector are designed mechanically and / or electromechanically. The latter also applies to the execution of the pipetting as a stationary device. When the pipetting device is designed as a (semi) automaton, all functions or a part of the functions of the pipetting devices (picking up and dispensing liquid, moving the pipetting devices into positions for picking up and dispensing liquid or pipette tips, picking up and dispensing pipette tips) are automatically carried out ,

According to one embodiment, the pipetting device has a series of parallel lugs for receiving pipette tips. It is a multi-channel pipetting system. Each approach of the pipetting device is associated with a separate displacement means or a common over a bayonet connection is connected to the drive device. It may be a common drive device for all displacement devices.

Fig. 1

eine Hand-Pipettiervorrichtung mit getrennter Kolben-Zylinder-Einheit und Abwerfer im Längsschnitt;

Fig. 2

dieselbe Pipettiervorrichtung mit verbundener Kolben-Zylinder-Einheit und Abwerfer im Längsschnitt;

Fig. 3

eine Mehrkanal-Pipettiervorrichtung in einem Vertikalschnitt von vom;

Fig. 4

dieselbe Mehrkanal-Pipettiervorrichtung in einem Vertikalschnitt von hinten.

The invention will be explained in more detail with reference to the accompanying drawings of exemplary embodiments. In the drawings show:

Fig. 1

a hand-held pipetting device with separate piston-cylinder unit and ejector in longitudinal section;

Fig. 2

the same pipetting device with connected piston-cylinder unit and ejector in longitudinal section;

Fig. 3

a multi-channel pipetting device in a vertical section of the;

Fig. 4

the same multi-channel pipetting device in a vertical section from behind.

The indications "top", "bottom", "horizontal", "vertical" and "front", "rear" refer to the orientations of the pipetting devices according to the drawings. These are orientations of the pipetting devices in which the pipette tip is arranged with its tip opening at the bottom, in order to receive liquid from a vessel located below the pipetting device or to deliver it into such a vessel.

The pipetting device according to Fig. 1 and 2 has an elongated, shaped as a handle housing 1 with an upper housing part 2 and a lower housing part 3. The upper housing part 2 with all the parts contained forms a drive means and the lower housing part 3 with all parts contained a displacement device. The upper housing part 2 forms a base body. It has at the top a screw cap 4. From this, an adjusting sleeve 5 projects upwards. The adjusting sleeve 5 is mounted axially non-displaceably and rotatably in the upper housing part 2.

In the adjusting sleeve 5, a push button 6 is arranged, which protrudes further upwards.

The push button 6 is connected to a lifting rod 7, which is passed through a spindle 8 in the Gehäuscobcrteil 2. The spindle 8 is screwed into an internal thread 9 of a bearing body 10 fixed in the housing upper part 2.

The spindle 8 has a rotatably connected to her driver 11 above. The driver 11 has on the circumference two diametrically opposed radial projections 12. The radial projections 12 engage in - not shown - axially extending grooves of the adjusting sleeve 5 a.

The spindle 8 has an end stop 13 in the form of radially outwardly projecting ribs. In the position shown, the end stop 13 is located a short distance below a shoulder 14 of the bearing body 10, with which it cooperates.

The lifting rod 7 has a flange 15 which rests in the position shown at the bottom of the spindle 8.

At the lower end of the bearing body 10, a spring plate 16 is arranged, which engages with a collar 17 in the bearing body 10. The spring plate 16 has an axially projecting, sleeve-shaped bearing portion 18 below, through which the lifting rod 7 is passed.

Further, the pipetting device on a spring, not shown, which pushes the lifting rod 7 upwards, so that the flange 15 rests against the underside of the spindle 8. For example, a coil spring between flange 15 and spring plate 16 is arranged.

At a distance below the spring plate 16, a coupling piece 19 is fixed in the housing. This has inside several pockets 20. These have an axially over the entire length of the coupling piece 19 extended longitudinal groove 21. Furthermore, they have at the upper end of the coupling piece 19 over a small part of the circumference of the coupling piece 19 extended annular groove 22. This has at a distance from upper end of the coupling piece 19 below a ramp-like boundary wall, which is increasingly approximated starting from the longitudinal groove 21 to the upper end of the coupling piece 19. Finally, the pockets 20 at the other end of the annular groove 22 have a short axial longitudinal groove portion 23 which terminates at a distance from the upper end of the coupling piece 19 in the coupling piece 19.

Between spring plate 16 and coupling piece 19, a spring 24 is arranged under bias, which is designed as a helical spring.

The adjusting sleeve 5 has on the circumference a sprocket 25 which cooperates with a gear 26 which drives a counter 27 with a plurality of superimposed on an axis 28 Zählwerksrädern 29. The Zählwerksräder 29 each have numerals from 0 to 9. the lower Zählwerksrad 29 is driven by the gear 26. The overlying Zählwerksräder 29 are further rotated in each case by one digit when the underlying Zählwerksrad 29 passes from 9 to 0.

The lower housing part 3 can be detachably connected to the upper housing part 2. For this purpose, the lower housing part 3 on the jacket of an upper, cylindrical Section 30 a plurality of outwardly projecting ribs 31 which extend in the axial direction of the cylindrical portion 30.

The lower housing part 3 has below the cylindrical portion 30 a plurality of conical sections 31 to 33 of different length and conicity, which emerge from the drawing. The conical section 33 is connected at the bottom with a long, slightly conical projection 34 for attaching a pipette tip. This in turn has a short, more conical Aufsteckende 35 below.

The lower housing part 3 houses a displacement device in the form of a piston-cylinder unit 36. This has a conical portion 32 arranged in the cylinder 37, in which a piston 38 dips. The piston 38 is connected at the top via a piston rod 39 with a pressure piece 40. The piston 38 forms a displaceable boundary of the cylinder 37.

Above the pressure piece 40, the lower housing part 3 has a piston holder 41, which bridges the cylindrical portion 30 above. The piston holder 41 has at the top a central passage 42, through which a lower portion of the piston 7 can be axially guided. Between the pressure piece 40 and conical portion 31, a lifting spring 43 is arranged, which is designed as a helical spring. By the lifting spring 43, the piston 38 and the piston rod 39 are passed.

The lifting spring 43 is biased and presses the pressure piece 40 against the piston holder 41, so that the piston 38 is pulled out of the cylinder 37 maximum.

A connecting channel 44 extends through the lug 34 and connects the cylinder 37 with an orifice in the push-on end 35.

Further, the pipetting device has a discharge device 45. The discharge device 45 has in the upper housing part 2 in addition to the adjustment knob 5, an operating button 46. The actuating button 46 is connected to a discharge bar 47 which extends parallel to the lifting rod 7 through the upper housing part 2 therethrough.

In the discharge rod 47, a transmission 48 is integrated. The gear 48 converts an axial actuating stroke of the actuating knob 46 into a smaller drive stroke with increased force. Suitable transmissions 48 are in the EP 0 992 288 A described generally in the general part of the description and specifically in the description of the figures, which are incorporated by reference into the present application.

The discharge rod 47 is supported via a further coil spring 49 in the upper housing part 2, so that the actuating button 46 is pressed into the initial position shown, in which it can be pressed against the action of the other coil spring 49.

The lower end of the discharge rod 47 projects into a receptacle 50 at the lower end of the housing upper part 2.

The discharge device 45 has on the lower housing part 3 a discharge sleeve 51. This is guided on the cylindrical portion 30, the conical portion 32 and the projection 34. Accordingly, the contour of the discharge sleeve 51 is equalized to the contours of the aforementioned sections of the housing lower part 3. In this case, the discharge sleeve 51 has internal steps 52, 53 which limit the sliding of the discharge sleeve 51 upwards by abutting against conical sections 31, 33 of the housing lower part 3.

Furthermore, the discharge sleeve 51 has laterally at the upper edge a projection 54 which has an axial bore 55 for pressing in the lower end of the discharge rod 47.

The pipetting device can be used as follows:

Upper housing part 2 and lower housing part 3 can be connected by axial insertion and rotation of the lower part 3 in the coupling piece 19. As a result, a bayonet connection is made. Here, the ribs 31 are inserted into the longitudinal grooves 21, rotated by the annular grooves 22 and inserted into the short Längsnutenabschnitte 23. In this case, the spring 24 presses against the upper edge of the cylindrical portion 30, whereby the lower housing part 3 is fixed in its fastening position, in which the ribs 31 abut against the lower ends of the Längsnutenabschnitte 23, which form a stop. Further, the discharge sleeve 51 is pressed with the bore 55 on the lower portion of the discharge rod 47. The dismantling of the upper housing part 2 and lower housing part 3 can be done in the reverse manner.

After connecting the upper housing part 2 and the lower housing part 3, the lifting rod 7 engages through the passage 42 and lies with its lower end against the pressure piece 40.

To set a volume to be pipetted, the adjustment sleeve 5 is rotated until the counter 27 indicates the desired volume. When turning the adjusting sleeve 5, the driver 11 is rotated due to the radial projections 12. As a result, the spindle 8 rotates in the internal thread 9 and displaced axially in the upper housing part 2 with entrainment of the flange 15 and thus the lifting rod 7. The radial projections 12 displace axially along the grooves on the inside of the adjusting sleeve 5. As a result, the stroke of the lifting rod 7 is changed, which is executable upon actuation of the push button 6.

Further, a pipette tip 56 is clamped on the lower end of the projection 34. The pipette tip 56 has a lower tip opening 57 for receiving and dispensing liquid.

When attaching the pipette tip 56 on the neck 34 increases with increasing progress of the Aufsteckens the Aufsteckkraft. If the Aufsteckkraft exceeds the force with which the spring 24 is biased, the projection 34 and thus the entire lower housing part 3 is pressed against the action of the spring 24 upwards. If the upper edge 58 of the pipette tip 56 presses against the lower edge of the ejection sleeve 51 forming a stop 59, a further lifting of the housing lower part 3 is prevented since the ejection sleeve 51 rests against a boundary 60 in the receptacle 50 of the housing upper part 2. The Aufsteckkraft and thus the ejection required for the ejection force are thus limited to a certain value.

For pipetting the push button 6 is pressed down, so that the piston 38 displaces air from the cylinder 37. Then, the pipette tip 56 is immersed with its lower tip opening 57 in the liquid to be pipetted. Thereafter, the push button 6 is released and the lifting rod 7 is returned to its original position under spring action. Similarly, the piston 38 returns under the action of the spring 43 to its original position. In this case, the piston 38 sucks liquid through the lower tip opening 57 into the pipette tip 56.

Thereafter, the lower tip opening 57 of the pipetting device is aligned to a delivery location. The liquid contained in the pipette tip 56 by pressing the push button 6, re-immersion of the piston 38 in the Cylinder 37 and expressing air through the connecting channel 44 delivered. After releasing the operating knob 6, the lifting rod 7 and the piston 38 again by spring force back to the starting position.

For dispensing the pipette tip 56 is pressed on the operation button 46. As a result, the ejection sleeve 51 moves downward and pushes the pipette tip 56 from the projection 34 from.

According to Fig. 3 and 4 For example, a dispensing head 61 of a multi-channel pipetting device has a housing 62 in which eight parallel piston-cylinder devices 63 are arranged in a row. Each piston-cylinder device 63 has a cylinder 64 into which a piston 65 dips.

On each cylinder 64 designed as a helical spring spring 66 is guided, which rests on the bottom of a circumferential projection 67 of the cylinder 64.

In the area of the peripheral projection 67, the cylinder 64 is guided in a guide rail 68.

Further, each cylinder 64 is connected below the peripheral projection 67 with a conical projection 69 for attaching a pipette tip 70.

Above the coil spring 66, the cylinders 64 are passed through a fixedly arranged in the housing 62 support plate 71. The springs 66 are supported on the underside of the support plate 71.

The cylinders 64 have a further circumferential projection above, which forms a spring bearing 72. Each spring bearing 72 is engaged by a console, not shown, which projects from the inside of the wall of the housing 62.

All pistons 65 are held at the top in a piston receptacle 73 in the form of a traverse. The Kolbenaufhahme 73 has a pin 74 at the top for connection to a lifting rod, not shown, which leads to a drive for the piston 65.

On all the pistons 65 more, designed as helical springs springs 75 are guided, which are supported on the bottom of the spring bearing 72 and are supported at the top of the underside of the piston seat 73.

Finally, in the housing 62, an ejector 76 is mounted in the form of an angled plate. This has in the lower horizontal leg 77 eight holes through which the lugs 69 are passed. The vertical leg 78 is connected via a shaft 79 with a discharge bar, not shown.

The pistons 65 are guided by a piston seal 80 in the cylinder 64.

The dispensing head 61 is connected to the lifting rod and the discharge rod of a drive device, not shown. When attaching pipette tips 70, the lugs 69 are moved upwardly within the housing 62 as the attachment forces exceed the forces that bias the springs 66. As soon as the pipette tips 70 abut the ejector 76 with their upper edges, the further attaching movement is stopped because the ejector 76 abuts against the underside of the guide rail 68 with the upper side of its horizontal leg 77. As a result, the Aufsteckkräfte and thus the forces required to eject the pipette tips 70 are limited.

For pipetting, the pistons 65 are moved by means of the lifting rod connected to the pin 74. For the ejection of the pipette tips 70 of the shaft 79 is moved by means of the lifting rod down so that the ejector 76 down is moved and with its leg 77, the pipette tips 70 from the lugs 69 depressed.

Further examples of the invention follow:

1. 1. Pipetting device with
   • a basic body (2),
   • at least one projection (34) projecting from the base body (2) and axially movably mounted on the base body (2) for fitting a pipette tip (56),
   • a spring (24), via which the projection (34) is supported on the base body (2),
   • a stop (59) associated with the lug (34), beyond which the lug (34) projects axially when not loaded with the spring (24), and
   • a release device (45) for releasing the pipette tip (56) from the lug (34) having an ejector (51) associated with the lug (34), the lug (34) and ejector (51) being movable relative to each other; a drive means (46, 47, 48) operatively connected to the ejector (51) and / or the shoulder (34) for relatively moving the ejector (51) and lug (34).
2. 2. Pipetting device according to Example 1, wherein the projection (34) is fixedly connected to a displacement device (36).
3. 3. Pipetting device according to Example 1 or 2, wherein the displacement means (36) via the spring (24) on the base body (2) is supported.
4. 4. Pipette device according to one of Examples 1 to 3, wherein the spring (24) in the axial direction of the projection (34) extending coil spring.
5. 5. Pipette device according to one of Examples 1 to 4, which has a prestressed spring (24).
6. 6. Pipetting device according to one of Examples 1 to 5, wherein the stop (59) axially relative to the projection (34) is movable and a fixed to the base body (2) connected boundary (60) for the axial movement of the stop (59) to the main body (2) is available.
7. 7. Pipetting device according to one of Examples 1 to 6, wherein the stop (59) on the ejector (51) is formed.
8. 8. The pipetting device according to one of Examples 1 to 7, wherein the projection (34) in the direction of the spring (24) away on a further stop (23) is supported, against which it is pressed by the spring (24).
9. 9. Pipetting device according to one of Examples 1 to 8, wherein the spring (24) is replaceable and / or means for adjusting the spring preload is present.
10. 10. Pipetting device according to one of Examples 1 to 9, wherein the drive means (46, 47, 48) against the action of a hand on a movable part of the Antriebseignchtigung (46, 47, 48) and on the other hand on the base body (2) supported further spring (49) is operable.
11. 11. Pipette device according to one of Examples 1 to 10, wherein the base body (2) has a carrier and / or a frame and / or a housing.
12. 12. Pipette device according to one of Examples 1 to 11, which is a hand-held device and / or a stationary device and / or an electrically driven and / or a (semi) automatic machine.
13. 13. The pipetting device according to one of Examples 1 to 12, which has a number of parallel lugs (69) for receiving pipette tips (70).
14. 14. Pipetting device according to Example 13, wherein each projection (69) via a separate spring (66) on the base body (62) is supported.
15. 15. Pipetting device according to Example 13 or 14, wherein the lugs (69) is associated with a common ejector (76).
16. 16. Pipette device according to one of Examples 1 to 15 with
    • a displacement device (36) having a displacement chamber (37) with a displaceable boundary (38), a projection (34) for connection to a pipette tip (56) and a connection channel (44) between the displacement chamber (37) and the free end of the projection (34)
    • a drive device (6, 7, 8) for driving the displaceable boundary (38) of the displacement device (36) with a drive element (7) which has a detachable operative connection with the displaceable boundary (38), and
    • a bayonet connection (19, 22, 30, 31) between the drive means (6, 7, 8) and the displacement means (36) which can be produced by establishing the operative connection between the drive member (7) and displaceable boundary (38) and by releasing the operative connection between drive member (7) and displaceable boundary (38) is releasable.
17. 17. The pipetting device according to Example 16, wherein the drive member (7) is a parallel to the longitudinal axis of the bayonet connection displaceable lifting rod of the drive means (6, 7, 8) and the displacement means (36) connected to the boundary (38), transverse to the lifting rod (7) directed contact surface which is pressed by a lifting spring (43) against the end of the lifting rod (7).
18. 18. The pipetting device according to Example 17, wherein the contact surface on a via a rod (39) connected to the boundary (38) pressure piece (40) is formed and at one end on the pressure piece (40) and the other end of the displacement chamber (37) as a helical spring trained lifting spring (43) is supported.
19. 19. The pipetting device according to one of examples 16 to 18, wherein the drive means (6, 7, 8) has a cylindrical receptacle (19) having at one end an opening through which the cylindrical receptacle (19) in the axial direction of is externally accessible, which has at least one axially directed longitudinal groove (21) which is connected to an annular groove (22) directed in the circumferential direction of the cylindrical receptacle (19), and wherein the displacement means (36) on a cylindrical portion (30) at least an outwardly projecting projection (31), wherein the cylindrical portion (30) in the axial direction of the cylindrical receptacle (19) through the opening in the receptacle (19) and with the projection (31) in the longitudinal groove (21) insertable and with the projection (31) in the annular groove (22) can be screwed.
20. 20. Pipetting device according to one of Examples 16 to 19, wherein the annular groove (22) at a distance from the longitudinal groove (21) in the axial direction of the Receiving (19) extending boundary wall up to which the projection (31) is rotatable.
21. 21. The pipetting device according to Example 19 or 20, wherein the annular groove (22) at a distance from the longitudinal groove (21) is connected to a parallel thereto extending Längsnutabschnitt (23) which terminates at a distance from the opening.
22. 22. Pipettiezvorrichtung according to one of Examples 19 to 21, wherein the annular groove (22) has a ramp-like boundary wall, the distance from the opening with increasing distance from the longitudinal groove (21) increases.
23. 23. The pipetting device according to one of Examples 19 to 22, wherein the longitudinal groove (21), the annular groove (22) and optionally the Längsnutabschnitt (23) are formed with a cylindrical coupling piece (19), the receiving the drive means (6, 7 , 8) forms and is fixed in this.
24. 24. The pipetting device according to one of Examples 16 to 23, wherein the drive device (6, 7, 8) has a spring (24) which is connected to the drive via the bayonet connection (19, 22, 30, 31) with the drive device (6, 7, 8) connected displacer (36) presses.
25. 25. The pipetting device according to Example 24, wherein the spring (24) is arranged on a further opening of the receptacle (19) which is opposite to the opening for the axial insertion of the displacement means (36).
26. 26. Pipetting device according to Example 24 or 25, wherein the spring (24) is a helical spring, which is supported on an inner end face of the coupling piece (19).
27. 27. Pipetting device according to one of examples 25 to 26, wherein the longitudinal groove (21) and / or the annular groove (22) and / or the Längsnutabschnitt (23) are open to the further opening.
28. 28. The pipetting device according to one of examples 16 to 27, wherein the displacement device (36) is a piston-cylinder device with a cylinder (37) and a piston (38) displaceable therein and the piston (38) has the displaceable boundary.
29. 29. Pipetting device according to one of Examples 16 to 28, wherein the projection (34) is aligned coaxially with the longitudinal axis of the bayonet connection (19, 22, 30, 31).
30. 30. The pipetting device according to one of Examples 16 to 29, wherein the projection (34) is fixedly connected to the displacement chamber (37)
31. 31. The pipetting device according to one of examples 16 to 30, with a discharge device (45) for releasing a pipette tip (56) from the projection (34), which has a drive device (6, 7, 8) arranged drop-off drive (46, 47, 48), an ejector (51) arranged on the displacement device (36) and a releasable axial clamping connection (47, 55) directed in the direction of the longitudinal axis of the bayonet connection (19, 22, 30, 31) between the ejection drive (45) and ejector ( 51).
32. 32. The pipetting device according to Example 31, wherein the ejection drive (45) of the drive device parallel to the bayonet connection (19, 22, 30, 31) projecting discharge rod (47) and the ejector (51) to the neck (34) parallel, axial Bore (55) which is press-connected to the discharge rod (47).
33. 33. Pipetting device according to Example 32, wherein the ejector (51) on the displacement means (36) is guided.
34. 34. The pipetting device according to one of Examples 16 to 33, wherein the ejector (51) is a guided on the displacement means (36) sleeve.

Claims (15)

Pipetting device with, a base body (2), - At least one of the main body (2) projecting, axially movable on the base body (2) mounted projection (34) for placing a pipette tip (56), - A spring (24) via which the projection (34) on the base body (2) is supported, - A stop (59) associated with the projection (34), beyond which the projection (34) protrudes axially when it is not loaded to the spring (24), and - A discharge device (45) for releasing the pipette tip (56) of the projection (34) having an approach (34) associated ejector (51), wherein projection (34) and ejector (51) are movable relative to each other. A pipetting device according to claim 1, wherein the lug (34) is fixedly connected to a displacing means (36). Pipetting device according to claim 1 or 2, wherein the displacement means (36) via the spring (24) on the base body (2) is supported. A pipetting device according to any one of claims 1 to 3, wherein the spring (24) is a helical spring extended in the axial direction of the lug (34). A pipetting device according to any one of claims 1 to 4, comprising a biased spring (24). Pipetting device according to one of claims 1 to 5, in which the stop (59) is movable axially with respect to the projection (34) and a limit (60) fixedly connected to the base body (2) for the axial movement of the stop (59) to the base body (2 ) is present. Pipetting device according to one of claims 1 to 6, wherein the stop (59) on the ejector (51) is formed. A pipetting device according to any one of claims 1 to 7, wherein the lug (34) is supported away from the spring (24) by a further stop (23) against which it is pressed by the spring (24). Pipetting device according to one of Claims 1 to 8, in which the drive device (46, 47, 48) counteracts the action of a further spring (49) supported on the one hand on a movable part of the drive device (46, 47, 48) and on the other hand on the main body (2) ) is operable. Pipetting device according to one of claims 1 to 9, wherein the base body (2) comprises a support and / or a frame and / or a housing. Pipetting device according to one of claims 1 to 10, which is a hand-held device and / or a stationary device and / or an electrically driven and / or a (semi) automatic device. A pipetting device according to any one of claims 1 to 11, comprising a series of parallel lugs (69) for receiving pipette tips (70). A pipetting device according to claim 12, wherein each lug (69) is supported on the body (62) by a separate spring (66). A pipetting device according to claim 12 or 13, wherein the lugs (69) are associated with a common ejector (76). Pipetting device according to one of claims 1 to 14 with - a displacement device (36) having a displacement chamber (37) with a displaceable boundary (38), a projection (34) for connection to a pipette tip (56) and a connecting channel (44) between the displacement chamber (37) and the free end of the Approach (34), - A drive means (6, 7, 8) for driving the displaceable boundary (38) of the displacement means (36) having a drive member (7) having a detachable operative connection with the displaceable boundary (38), and - A bayonet connection (19, 22, 30, 31) between the drive means (6, 7, 8) and the displacement means (36) producing the operative connection between the drive member (7) and displaceable boundary (38) producible and under solution of Actual connection between the drive member (7) and displaceable boundary (38) is releasable

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