EP2659978A1 - Pipette with blocking system - Google Patents

Abstract

The pipette (1) has a transfer element (19) and display adjustable unit (23) that are coupled to the transmitting portions (20,21) for transmitting a rotary movement of the transfer element to a movement of display adjustable unit. A circular cylindrical locking element is arranged on the outer circumference of the transfer element. The locking portion and the unlocking elements (106) are coupled to the transmitting unit for transferring the movement of the unlocking element relative to the housing to the movement of the locking portion from the locking position.

Description

The invention relates to a pipette for exchangeable pipette tips.

Pipettes are used especially in the laboratory for dosing liquids. For this purpose, a pipette tip with an upper opening is clamped on a seat of the pipette. The seat is usually a conical or cylindrical projection relative to a housing of the pipette, on which a pipette tip can be clamped with the upper opening. Through a lower opening, the pipette tip can absorb and dispense liquid. Bubble pipettes include an air displacement device communicating with the pipette tip through a hole in the seat. By means of the displacement device, an air cushion is displaced, so that liquid is sucked into the pipette tip and ejected therefrom. For this purpose, the displacement device has a displacement chamber with a displaceable boundary. The displacement device is usually a cylinder with a piston displaceable therein.

The pipette tips are released from the seat after use and replaced with a fresh pipette tip. As a result, contamination can be avoided at subsequent dosages. In most cases, pipette tips have a discharge device for ejecting the pipette tips, which allow ejection by button operation without touching the pipette tips. Single-use pipette tips are available inexpensively from plastic.

The displaceable boundary is coupled to a drive device which serves to displace the piston in the cylinder. The drive device has a lifting rod, which with a stop element between an upper and a lower stop is displaceable. At the beginning of the suction of air into the displacement chamber, the stop element is located at the lower stop. At the beginning of the displacement of air from the cylinder, the stop element is located at the top stop. The absorbed or dispensed amount of liquid depends on the stroke of the movable limit and thus from the stroke of the lifting rod. The stroke volume of the displaceable boundary does not correspond exactly to the amount of liquid absorbed and dispensed. Since the air column lengthens slightly under the weight of the liquid, the stroke volume exceeds the liquid volume. The deviation of stroke volume and liquid volume depends in particular on the density and viscosity of the liquid, the temperature, the air pressure and wetting effects. It is known, for example from the WO 03/033151 or US-A-3,827,305 To calibrate pipettes by adjusting the position of an upper stopper body to a specific dosing volume.

For fixed volume pipettes, the distance between the top and bottom stops is constant. From the US 4,020,698 is a fixed volume pipette with an upper stop body in the form of an adjustable by means of a calibration tool threaded sleeve known.

For pipettes with adjustable dispensing volume, the position of the top stop is variable. Known pipettes have an upper stop body in the form of a threaded spindle which is adjustable in a fixedly arranged in the housing spindle nut. To adjust the threaded spindle adjusting devices are available, which are coupled with display devices for displaying the set metering volume in the form of a counter.

The DE 43 35 863 C1 and US 5,531,131 describe a pipette in which a cylindrical actuator protrudes from the top of the housing and with the connected to the upper end of a lifting rod, which is connected at the lower end with the piston. The lifting rod is passed through the upper passage channel of a threaded spindle and the lower passage channel of a lower stop body. It has a stop element in the form of an outwardly projecting bead, which limits the movement of the lifting rod between the threaded spindle and the lower stop body. By pressing the actuating element against the force of a return spring, the piston is moved deeper into the cylinder until the stop element bears against the lower stop body. After relieving the actuator returns due to the action of the return spring of the piston in its initial position, in which the stop element bears against the threaded spindle. Adjustment means for adjusting the threaded spindle have an adjusting sleeve, which projects up out of the housing and in which the actuating button is axially displaceable. The adjusting sleeve is rotatably mounted in the housing and rotatably connected via drivers with the upper end of the threaded spindle. By turning the adjusting sleeve, the threaded spindle is displaceable with the spindle nut, wherein the drivers are axially displaceable in the axial grooves of the adjusting sleeve.

Furthermore, pipettes are known in which a cylindrical actuating element also serves as an adjusting element for adjusting the threaded spindle. For this purpose, the actuator is rotatably and axially displaceable connected to the upper end of the threaded spindle. A driver in the form of a polygon at the upper end of the threaded spindle immersed in a complementary axial receptacle of the actuating element. The actuating element is arranged displaceably in an opening of a sleeve-shaped transmission part, which is rotatably mounted in the housing. The actuator is rotatably connected to the transmission part via drivers in the form of outwardly projecting ribs which engage in axial grooves of the transmission part. The transmission part has outside on Circumference to a sprocket with axially projecting teeth into which engages a gear of a counter, which serves to display the set dosing volume.

The known pipettes have a lock that prevents unintentional changes during dosing a set dosing volume. For this purpose, an axially directed tooth on a lever arm of a two-armed lever, which is pivotable about a horizontal axis, engages between two adjacent axially directed teeth of a ring gear on the circumference of the transmission part. In this locking position, the lever is pressed by a spring. To unlock a button is present, which partially protrudes from the housing and acts within the housing via a tapered surface on the other lever arm of the lever. Depressing the button deeper into the housing will pivot the lever so that the tooth is clear of the sprocket. In this position, the actuator is rotatable to adjust the Dosiervolumens. Such locking the rotational position of the confirmation element is in the EP 0 527 170 B1 described.

The known locking has the disadvantage that it can be destroyed in the locked position by turning the actuating element with increased force. In addition, it is cumbersome to depress the release button and at the same time to adjust the dosing volume. Moreover, the operation of the wedge gear formed by the key and the lever requires a relatively high expenditure of force. Furthermore, the engagement of the tooth in the ring gear of the transmission part limits the fineness of the adjustment of the metering volume. In addition, the assembly of many items is expensive.

Based on this, the object of the invention is to provide a pipette with a releasable locking of the rotational position of the actuating element, which has favorable application properties.

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

• ● ein stangenförmiges Gehäuse,
• ● einen Sitz zum lösbaren Halten einer Pipettenspitze am unteren Ende des Gehäuses,
• ● eine Verdrängungseinrichtung umfassend eine Verdrängungskammer mit einer darin verlagerbaren Begrenzung,
• ● einen die Verdrängungskammer mit einer Öffnung im Sitz verbindenden Verbindungskanal,
• ● eine mit der verlagerbaren Begrenzung gekoppelte Antriebseinrichtung zum Verlagern der verlagerbaren Begrenzung der Verdrängungseinrichtung,
• ● einstellbare Mittel zum Begrenzen der Verlagerung der verlagerbaren Begrenzung durch die Antriebseinrichtung,
• ● ein mit der Antriebseinrichtung verbundenes, aus dem oberen Ende des Gehäuses herausstehendes Betätigungselement zum Steuern einer Verlagerung der verlagerbaren Begrenzung durch Verlagern entlang einer Achse und zum Einstellen der einstellbaren Mittel zum Begrenzen durch Drehen des Betätigungselements,
• ● ein zylindrisches Übertragungsteil, das im Gehäuse drehbar und in Axialrichtung an einer bestimmten Position gelagert ist, wobei das Betätigungselement in einer axial erstreckten Aufnahme des Übertragungsteils verlagerbar und über Mittel zum drehfesten Verbinden drehfest mit dem Übertragungsteil verbunden ist,
• ● mit dem Betätigungselement und den einstellbaren Mitteln zum Begrenzen der Verlagerung gekoppelten ersten Mitteln zum Übertragen einer Drehbewegung des Betätigungselement auf eine Bewegung zum Einstellen der einstellbaren Mittel zum Begrenzen der Verlagerung,
• ● einstellbare Mittel zum Anzeigen eines Dosiervolumens mit einer von außen sichtbaren Anzeige,
• ● mit dem Übertragungsteil und den einstellbaren Mitteln zum Anzeigen gekoppelten zweiten Mitteln zum Übertragen einer Drehbewegung des Übertragungsteils auf eine Bewegung zum Einstellen der einstellbaren Mittel zum Anzeigen,
• ● ein kreiszylindrisches Verriegelungselement am äußeren Umfang des Übertragungsteils,
• ● einen Verriegelungskörper mit einer teilzylindrischen Wirkfläche, die in Verriegelungsstellung am Umfang des Verriegelungselements anliegt,
• ● Mittel zum Verlagern des Verriegelungskörpers in die Verriegelungsstellung,
• ● mindestens ein vom Gehäuse vorstehendes, bezüglich des Gehäuses beweglich gelagertes Entriegelungselement und
• ● mit dem Verriegelungskörper und dem Entriegelungselement gekoppelte dritte Mittel zum Übertragen einer Bewegung des Entriegelungselements bezüglich des Gehäuses auf eine Bewegung des Verriegelungskörpers aus der Verriegelungsstellung vom Verriegelungselement weg.

The pipette according to the invention has

• ● a rod-shaped housing,
• A seat for releasably holding a pipette tip at the lower end of the housing,
• ● a displacement device comprising a displacement chamber with a movable therein limit,
• ● a connecting channel connecting the displacement chamber to an opening in the seat,
• ● a drive device coupled to the displaceable boundary for displacing the displaceable boundary of the displacement device,
• Adjustable means for limiting the displacement of the displaceable boundary by the drive device,
• An actuator connected to the drive means and projecting out of the upper end of the housing for controlling a displacement of the displaceable boundary by displacing along an axis and for adjusting the adjustable means for limiting by rotating the actuator,
• A cylindrical transmission part, which is rotatably mounted in the housing and in the axial direction at a certain position, wherein the actuating element in an axially extending receptacle of the Transfer parts displaceable and rotatably connected via means for non-rotatable connection with the transmission part,
• ● first means coupled to the actuator and adjustable displacement limiting means for transmitting rotary motion of the actuator to motion for adjusting the adjustable displacement limiting means,
• ● adjustable means for indicating a dosing volume with an externally visible display,
• ● Second means, coupled to the transmission part and the adjustable means for displaying, for transmitting a rotational movement of the transmission part to a movement for setting the adjustable means for displaying,
• ● a circular-cylindrical locking element on the outer circumference of the transmission part,
• A locking body with a part-cylindrical active surface, which rests in the locking position on the circumference of the locking element,
• ● means for displacing the locking body into the locking position,
• ● at least one of the housing projecting, with respect to the housing movably mounted unlocking and
• ● Third means coupled to the locking body and the unlocking element for transmitting movement of the unlocking element relative to the housing to movement of the locking body out of the locking position away from the locking element.

In the case of the pipette according to the invention, a set metering volume is ensured by arranging the locking body in the locking position on the circumference of the circular-cylindrical locking element. As a result, the transmission part is held, which the locking element on the outside Has circumference. The circular cylindrical locking element may be formed separately from the sprocket for driving a counter. This makes it possible to make the lock in any position or in more selectable rotational positions than in the conventional lock, in which engages a locking element in the sprocket for driving the counter. This will reduce errors in the adjustment of the dosing volume. Furthermore, finding a locking point is facilitated. The part-cylindrical active surface of the locking body may be formed larger than the one tooth of the locking lever in the prior art. Thus, the lock is less easily overcome or destroyed and the security of the lock is improved. Furthermore, it is advantageous that the locking body, the unlocking element and the third means for transmitting a movement to save space above a sprocket for driving a counter can be accommodated. In this case, the third means for transmitting come without a frictional and the operating force increasing wedge gear.

According to one embodiment, the pipette on opposite sides of the housing from the housing projecting unlocking elements, which are each coupled via third means for transmitting with the locking body to selectively displace the locking body away from the locking element by pressing the one or the other unlocking. This embodiment is particularly advantageous in terms of the use of the pipette by left and right handed people, for both of which an easily accessible unlocking element is available.

According to one embodiment, the locking element is a sprocket on the circumference of the transmission part with radially outwardly directed teeth and has the locking body on the part-cylindrical effective surface a sprocket with radially inwardly directed teeth, which engage in the locking position in the teeth of the locking element. In another embodiment, the locking element is ferromagnetic and the locking body is a magnetic body. According to another embodiment, the locking element is a brake cylinder and the locking body is a brake shoe. The first two and the last two variants can also be realized in combination.

Preferably, the sprocket of the locking body has at least five teeth and / or at most 35 teeth, more preferably at least 15 and at most 25 teeth.

According to a further embodiment, the third means for transmitting a two-armed lever with a first lever arm acting on the locking body on a second lever arm, which acts either on the unlocking element or itself is the unlocking element. This embodiment is space-saving feasible and allows a power-saving unlocking. It favors designs in which the locking body is brought into the locking position with a particularly high force, so that the locking is particularly secure.

According to a further embodiment, the lever arms of the two-armed lever are mutually obtuse inclined and / or extends in an arc around the actuating element. This embodiment is also advantageous for space-saving accommodation around the transmission part.

According to a further embodiment, the unlocking element has a further lever pivotally mounted in the housing with one on the third means for transferring acting lever arm and a housing projecting from the operating portion. This embodiment enables a power transmission via a transmission of a plurality of lever arms, which facilitates unlocking. It favors designs in which the locking body is brought into the locking position with a particularly high force, so that the locking is particularly secure.

According to a further embodiment, means for locking the further lever in an unlocking position are provided between the further lever and the housing. This design favors the adjustment of the dosing volume with a single hand, because the user can release the other lever in the unlocked position and then easily turn the actuator with your thumb and forefinger.

According to a further embodiment, the means for displacing the locking body into the locking position comprise a spring element which is supported on a spring bearing fixedly connected to the housing and loads the locking body in the locking position. The spring element holds the locking body in the locking position, when the unlocking element is relieved. Upon actuation of the unlocking the locking body is moved away against the action of the spring element from the locking position. After relieving the unlocking element, the spring element moves the locking body back into the locking position. In this case, the spring element preferably also moves the third means for transmitting and the unlocking element back into a starting position, from which the unlocking can take place by actuating the unlocking element. According to a preferred embodiment, the spring element is a helical spring or conical spring.

According to a further embodiment, a further spring element is present, which is supported on a fixedly connected to the housing bearing and loads the unlocking in unlocked position. The unlocking element is actuated against the action of the further spring element and is moved back from this after release in the unlocked position.

In an alternative embodiment, the unlocking element can be actuated in two different directions, and the locking body is coupled to the unlocking element via the third means for transmitting such that the locking body can be moved away from the locking position and thus unlocked by actuating the unlocking element in one direction by actuating the unlocking element in the other direction, the locking body is movable back into the locking position.

According to a further embodiment, the second means for transmitting a sprocket with axially directed teeth on the outer periphery of the transmission part, in which engages a gear of the means for displaying. Thus, this embodiment corresponds to the conventional pipette, but in contrast to the conventional pipette, the circular cylindrical locking element is designed separately from the sprocket with axially directed teeth. When the circular-cylindrical locking element is designed as a toothed ring, it preferably has more teeth than the toothed ring with the axially directed teeth. Preferably, the number of teeth of the circular cylindrical locking element is at least twice as large, more preferably at least three times as large as the number of teeth of the ring gear with the axially directed teeth.

According to a further embodiment, the drive device has an axially displaceable lifting rod for displacing the displaceable boundary of the displacement device, the adjustable means for limiting a displaceable in the axial direction of the lifting rod upper stop body, a lower stop body and arranged between the upper and lower stop body stop element on the circumference of the lifting rod for limiting the stroke and the actuating element is connected to the lifting rod. According to a preferred embodiment, a return spring is present, which is supported on a bearing fixedly connected to the housing and the drive mechanism loaded in a starting position in which the stop element rests against the upper stop body. Contrary to the action of the restoring spring, the displaceable boundary can be displaced into the displacement chamber by actuation of the actuating element in order to eject fluid from the pipette tip. After relieving the actuator, the return spring moves the drive mechanism and thus the movable limit back to the starting position to suck liquid into the pipette tip.

According to a further embodiment, the upper stop body is a threaded spindle having an upper passageway through which the lifting rod is passed and which is screwed into a fixedly connected to the housing spindle nut and the lower stopper body has a lower passageway through which the lifting rod extends therethrough is and is the lifting rod with the stop element between the upper stop body and the lower stop body displaced. Alternatively, instead of a threaded spindle, a toothed rack is provided which is adjustable by means of a toothed gear and has the upper stop body at the lower end.

These embodiments of the drive device and adjustable means for limiting the displacement are structurally simple and allow accurate adjustment of the metering volume.

According to a further embodiment, the first means for transmitting further means for non-rotatably connecting the actuating element to the threaded spindle, which allow an axial displacement of the actuating element with respect to the threaded spindle. This configuration of the first means for transmitting ensures that a rotational movement of the actuating element is transmitted to the threaded spindle and the actuating element is axially displaceable relative to the threaded spindle.

According to a further embodiment, the further means for non-rotatable connection of actuating element and threaded spindle on a polygon, which engages in a complementary axially extending receptacle of the actuating element.

According to a further embodiment, one or more of the following components are mounted on a base plate which is mounted in the housing: counter, counter gear, locking body, lever, unlocking element, spring element, another spring element. The components can be pre-mounted on the base plate and the pipette can be fitted with the pre-assembled base plate. As a result, a mounting seal is achieved.

The pipette according to the invention is preferably a hand-held pipette. This is a pipette that can be held and operated by a user when pipetting with just one hand. Preferably, the pipette is a mechanically driven pipette. Basically it is also possible to use the pipette with a electric drive or a mechanical drive with power assistance by an electric drive (servo drive) form.

Fig. 1

eine erfindungsgemäße Pipette in einem Längsschnitt;

Fig. 2

dieselbe Pipette in einem vergrößerten Längsschnitt durch einen oberen Teil;

Fig. 3

ein vergrößerter Schnitt entlang der Linie III - III von Fig. 2;

Fig. 4

vergrößertes Detail IV von Fig. 2;

Fig. 5

dieselbe Pipette in einem vergrößerten Längsschnitt durch einen unteren Teil;

Fig. 6

dieselbe Pipette ohne Hubkörper in einem vergrößertem Längschnitt durch einen unteren Teil;

Fig. 7

Übertragungsteil mit Zählwerk und Verriegelungseinrichtung in dem Gehäuse der Pipette bei abgenommener Gehäuseabdeckung in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 8

dieselbe Anordnung aus einer anderen Perspektive;

Fig.9

Übertragungsteil mit Zählwerk und Teilen der Verriegelungseinrichtung in dem Gehäuse der Pipette in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 10

Übertragungsteil mit Teilen des Zählwerks und Verriegelungseinrichtung in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 11

Übertragungsteil mit Verriegelungseinrichtung in einer vergrößerten Teilansicht von oben;

Fig. 12

Zählwerk mit Verriegelungseinrichtung in einer vergrößerten Teilansicht schräg von unten;

Fig. 3

Übertragungsteil mit Zählwerk und Teilen der Verriegelungseinrichtung in entriegeltem Zustand in einer perspektivischen Teilansicht schräg von oben und von der Seite;

Fig. 14

Übertragungsteil mit Verriegelungseinrichtung in entriegeltem Zustand in einer vergrößerten Teilansicht von oben;

Fig. 15

Übertragungsteil mit Teilen des Zählwerks und Teilen einer Variante der Verriegelungseinrichtung in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 16

die Bauteile von Fig. 15 ohne den Bedienknopf in einer Perspektivansicht schräg von unten und von der Seite;

Fig. 17

die Bauteile von Fig. 15 in entriegeltem Zustand in dem Gehäuse der Pipette bei abgenommener Gehäuseabdeckung in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 18

Übertragungsteil mit Teilen des Zählwerks und einer weiteren Variante der Verriegelungseinrichtung im Gehäuse der Pipette bei abgenommener Gehäuseabdeckung in einer Perspektivansicht schräg von oben und von der Seite;

Fig. 19

dieselbe Anordnung bei entriegelter Verriegelungseinrichtung in derselben Perspektivansicht;

Fig. 20a bis d

dieselbe Pipette vor dem Betätigen des Betätigungselement (Fig. 20a), nach dem vollständigen Ausführen des Dosierhubes und vor Ausführung des Überhubes (Fig. 20b). nach dem Ausführen des Überhubes vor dem Abwerfen der Pipettenspitze (Fig. 20c) und nach dem Abwerfen einer Pipettenspitze (Fig. 20d) jeweils in einem teilweisen Längsschnitt.

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

Fig. 1

a pipette according to the invention in a longitudinal section;

Fig. 2

the same pipette in an enlarged longitudinal section through an upper part;

Fig. 3

an enlarged section along the line III - III of Fig. 2 ;

Fig. 4

enlarged detail IV of Fig. 2 ;

Fig. 5

the same pipette in an enlarged longitudinal section through a lower part;

Fig. 6

the same pipette without lifting in an enlarged longitudinal section through a lower part;

Fig. 7

Transfer unit with counter and locking device in the housing of the pipette with the housing cover removed in a perspective view obliquely from above and from the side;

Fig. 8

the same arrangement from a different perspective;

Figure 9

Transfer part with counter and parts of the locking device in the housing of the pipette in a perspective view obliquely from above and from the side;

Fig. 10

Transmission part with parts of the counter and locking device in a perspective view obliquely from above and from the side;

Fig. 11

Transmission part with locking device in an enlarged partial view from above;

Fig. 12

Counter with locking device in an enlarged partial view obliquely from below;

Fig. 3

Transmission part with counter and parts of the locking device in the unlocked state in a perspective partial view obliquely from above and from the side;

Fig. 14

Transmission part with locking device in the unlocked state in an enlarged partial view from above;

Fig. 15

Transmission part with parts of the counter and dividing a variant of the locking device in a perspective view obliquely from above and from the side;

Fig. 16

the components of Fig. 15 without the control knob in a perspective view obliquely from below and from the side;

Fig. 17

the components of Fig. 15 in the unlocked state in the housing of the pipette with the housing cover removed in a perspective view obliquely from above and from the side;

Fig. 18

Transmission part with parts of the counter and a further variant of the locking device in the housing of the pipette with the housing cover removed in a perspective view obliquely from above and from the side;

Fig. 19

the same arrangement with unlocked locking device in the same perspective view;

Fig. 20a to d

the same pipette before operating the actuator ( Fig. 20a ), after complete execution of the metering stroke and before execution of the overstroke ( Fig. 20b ). after performing the overtravel before dropping the pipette tip ( Fig. 20c ) and after dropping a pipette tip ( Fig. 20d ) each in a partial longitudinal section.

In the present application, the terms "up" and "down", "above" and "below" and "horizontally" and "vertically" refer to an orientation of the pipette in which the housing is vertically aligned with the seat. In this orientation, a pipette tip mounted on the seat can be directed to an underlying vessel to aspirate or dispense liquid.

According to Fig. 1 and 2 the pipette 1 has a rod-shaped, designed as a handle housing 1.1 with an upper housing part 2 and a lower housing part 3. Das Upper housing part 2 with all parts contained forms a drive unit and the lower housing part 3 with all the parts contained a displacement unit. From the upper housing part 2 is above an actuator 4 in the form of a cylindrical push button out. The actuating element 4 is mounted axially displaceably and rotatably in the upper housing part 2.

The actuating element 4 is screwed with a thread in a cover 5 on a cylindrical lifting rod 6. The lifting rod 6 is passed in the upper housing part 2 through an upper passage channel 7 of a threaded spindle 8. The threaded spindle 8 is screwed into an internal thread of a housing upper part 2 held in a defined position spindle nut 9.

The spindle nut 9 is fixedly connected to a lifting body 10 which is fixed in the upper housing part 2. The lifting body 10 is substantially cylindrical and is a support for the spindle nut 9, the threaded spindle 8 screwed therein and the lifting rod 6 guided therein. During assembly of the pipette, these and other components are preassembled on the lifting body 10 and the lifting body 10 equipped with the components is mounted in the upper housing part 2, so that it is firmly held in the upper housing part 2. For this purpose, the lifting body 10 is locked to the upper housing part 2. In principle, it is also possible to mount the components preassembled on the lifting body 10 directly in the upper housing part 2. For this purpose, the upper housing part 2 can be equipped inside corresponding to the lifting body 10.

The threaded spindle 8 has a rotatably connected thereto Spindelmitnehmer 11 above. The Spindelmitnehmer 11 has on the circumference a hexagon 12 with a central hole 13. The hexagon 12 engages in a Innsensechskant 14 of the actuating element 4 a.

The actuator 4 is provided at the bottom with two diametrically opposed, radial projections 15, 16 which project outwardly. Preferably, four radial projections 15, 16 are present. The radial projections 15, 16 engage in axially extending grooves 17, 18 on the inside of a hollow cylindrical transmission part 19, which is rotatably mounted in the upper housing part 2. The transmission member 19 has at the top of the outer circumference a sprocket 20 which meshes with a gear of a counter gear 21 which drives a plurality of juxtaposed on a horizontal axis counter wheels 22 of a counter 23. The counter 23 is attached to the upper housing part. The Zählwerksräder 22 each have digits from 0 to 9. Das - based on Fig. 1 - The last counter gear 22 is driven by the counter gear 21. The counter wheels 22 arranged next to them are each further rotated by one digit when the meter wheel arranged behind them passes from 9 to 0.

Above the counter 23, the upper housing part 2 has a housing cover 24 with a window through which the digits of the counter wheels 22 can be read.

Below the threaded spindle 8, a beaded collar 25 is arranged as a stop element on the lifting rod 6. The displacement of the lifting rod 6 upwards is limited by contact of the collar 25 at the lower end face 26 of the threaded spindle 8, which forms an upper stop body for the collar 25.

Below the spindle nut 9, a substantially disc-shaped lower stop body 27 is arranged in the lifting body 10. The lower stop body 27 has a cup-shaped depression, in which a central passageway 28 is arranged centrally. Further, the lower stopper body 27 a plurality (eg, three or four) radially outwardly projecting projections 29 which are evenly distributed around its circumference.

The lower stop member 27 is guided on the projections 29 in axially extending guide slots 30 of the lifting body 10. This is also in Fig. 3 shown. Upwards he is 30 until the projection of the projections 29 at the upper end of the guide slots 30 displaced.

Below the lower stop body 27, a lifting spring 31 designed as a helical spring is arranged in the lifting body 10. At the top, the overstroke spring bears against the lower side of the lower stop body 27. At the bottom, the overstroke spring 31 is supported on an over-stroke spring bearing 32 which is arranged in the upper housing part 2 and thus firmly connected.

The over-stroke spring bearing 32 is formed by a ring with L-section, wherein the horizontal leg of the L-profile surrounds a central through hole 33 of the overstroke spring bearing 32. The overstroke spring 31 is supported on the horizontal leg of the L-profile and is laterally bordered by the vertical leg. The overstroke spring 31 presses the lower stopper body 27 with the protrusions 29 under bias against the upper ends of the guide slots 30.

Below the lower stopper body 27, a drive element 34 in the form of a coaxial with the lifting rod 6 aligned sleeve is present in the lifting body 10. The drive member 34 has an upper sleeve portion 35 and a lower sleeve portion 36, wherein the upper sleeve portion 35 has larger inner and outer diameter than the lower sleeve portion 36. The lower sleeve portion 36 has a frusto-conical tip 37 at the bottom.

At the upper edge of the upper sleeve portion 35, a radially outwardly projecting, further circumferential collar 38 is present. The outer diameter of the upper sleeve portion 35 is smaller than the inner diameter of the through hole 33 of the overstroke spring bearing 32, so that the lower and the upper sleeve portion 35, 36 are insertable into the through hole 33. The outer diameter of the further collar 38 exceeds the inner diameter of the through-hole 33, so that the drive element 34 can not completely pass through the through-hole 33. The over-stroke spring bearing 32 forms an end stop and the further collar 38 an end stop element, which limit the displacement of the drive element 34 down.

In the upper sleeve portion 35, a hollow cylindrical armature 39 is arranged from a ferromagnetic material above. Below this, a hollow cylindrical magnet 40 is arranged in the upper sleeve section 35. Below this is a pot 41 which receives the magnet 40. The armature 39 has an interference fit in the upper sleeve portion 35. The lifting rod 6 extends slidably through the central hole of the armature 39 therethrough. Below the armature, the lifting rod 6 has a needle-shaped portion 42 of reduced diameter. The magnet 40 and the pot 41 are seated on the needle-shaped portion 42. Preferably, the magnet 40 and cup 41 are fixed on the needle-shaped portion 44, e.g. by having a press fit there. In addition, the magnet 40 is supported at the top on a shoulder of the lifting rod from which the needle-shaped portion 44 extends.

Below the annular disc 41 is formed on the needle-shaped portion 42 designed as a helical spring decoupling spring 43, which is supported at the bottom 43 of the lower sleeve portion 36 below. Armature 39, magnet 40 and decoupling spring 43 are components of a decoupling device 44.

According to FIG. 1 . 2 . 5 and 6 has the upper housing part 2 is provided below next to a lower housing opening 45 on the inner circumference with unspecified means for releasably connecting 46 with further means for releasably connecting the housing lower part 3.

The lower housing part 3 has a hollow cylindrical section 47 at the top, followed by a short upper hollow cone section 48 with a large cone angle, followed in turn by a long lower hollow cone section 49 with a small cone angle, with its lower end a conical projection 50 for clamping a pipette tip 51 forms. A clamped pipette tip 51 is also substantially conical with an upper opening 52 for attachment to the lug 50 and a lower opening 53 for the passage of liquid. The upper opening 52 is substantially larger than the lower opening 53 and from the upper to the lower opening, the pipette tip 51 tapers.

The hollow cylindrical portion 47 of the lower housing part 3 is provided at the top of the outer circumference with other means for releasable connection 54, which are not described in more detail, which are adapted to the means for releasably connecting 46 of the upper housing part 2 to releasably connect the lower housing part 3 with the upper housing part 2. Suitable means for releasably connecting 46, 54 of the upper housing part 2 and lower housing part 3 are in the DE 10 2004 003 434 B4 described. In this regard, reference is made to the DE 10 2004 003 434 B4 and US2005 / 155438 A1 , the content of which is hereby incorporated into this application.

The lower hollow cone section 49 has at the top a projection 55 projecting beyond the upper hollow cone section 48 in the lower housing part 3.

The lower hollow cone portion 49 has a connecting channel 56 which connects the upper end face of the extension 55 with the lower end face of the projection 50.

In the lower housing part 3, an arrangement of a cylinder 57 is arranged with a displaceable piston 58 therein. The cylinder 57 is inserted with a lower portion in the connecting channel 56 and fixed therein by press-fitting or gluing. At the bottom, the cylinder 57 is sealed off from the connecting channel 56 by means of an O-ring 59.

The piston 58 has on the circumference a piston seal 60, which seals on the inside of the cylinder 57. Below the piston seal 60, the piston 58 has a needle-shaped extension 61, which is insertable into a through-opening 62 in the bottom of the cylinder 57 and into the connecting channel 56 in order to reduce the dead volume. Cylinder 57 and piston 58 are vertically aligned. At the top, the piston 58 carries a horizontally oriented piston plate 63, which has at the center a vertically oriented, conical recess 64 for receiving the tip 37 of the drive member 34.

The lower housing part 3 has at the top a pot-shaped closure cap 65 with a cylindrical or conical jacket. The bottom of the cap 65 is disposed above the piston plate 63 and has a central upper housing opening 67, through which the piston plate 63 is accessible from above. At the edge of your shell, the cap 65 has outwardly projecting protrusions 68 which are snapped into corresponding recesses 69 of the hollow cylindrical portion 47 of the housing base 3.

The bottom of the cap 65 limits the displacement of the piston 58 upwards. A trained as a spiral spring piston spring 70, the bottom of the extension 55th and supported on top of the underside of the piston plate 63, biases the piston 58 against the underside of the closure cap 65.

Furthermore, the pipette 1 has a discharge device 71. The discharge device 71 comprises a discharge slide 72, which is arranged on the housing lower part 3. The discharge slide 72 has a contour adapted to the contours of the hollow cylindrical section 47, the upper hollow cone section 48 and the lower hollow taper section 48. Below it has an annular discharge end 73. The discharge end 73 is in the position of the discharge slide 72 of Fig. 1 pushed as far as possible up to the lower housing part 3, so that the conical projection 50 is free for attaching a pipette tip 51.

Above the discharge slide 72 is connected to a discharge extension 74. This includes three vertical discharge bars 75, which are connected to the upper edge of the discharge slide 72. The discharge bars 75 are evenly distributed over the upper edge of the discharge slide 72. The discharge bars 75 are connected at the bottom via a first snap connection with a discharge ring 76, which is connected via a second snap connection with the upper edge of the discharge slide 72. At a distance from the Abwurfring 76, the discharge rods 75 are connected at the top at its inner periphery by an annular upper Abwurffederlager 77 with each other. The upper Abwurffederlager 77 has an L-shaped cross section, wherein the horizontal leg of the cross section, the through hole 33 adjacent to the Überhubfederlagers 32. The vertical, circumferential leg of the upper Abwurffederlagers 77 is directed downward.

The discharge bars 75 have actuation ends 78 at the top.

The discharge extension 74 and the discharge bars 75 are hineinerstreckt through the lower housing opening 45 in the upper housing part 2. The displacement of the Abwurfverlängerung 74 upwards is limited by conditioning the upper Abwurffederlagers 77 on the underside of the Überhubfederlagers 32.

Below the upper Abwurffederlagers 77 are from the inside of the upper housing part 2 before three webs 79, which are arranged distributed uniformly over the inner circumference and pass through recesses of the lifting body 10. This is especially in FIG. 4 shown. The webs 79 form a lower ejection spring bearing 80. An ejector spring 81 designed as a helical spring is arranged under pretension between the upper ejection spring bearing 77 and the lower ejection spring bearing 80 and presses the ejection device 71 upwards so that the upper ejection spring bearing 77 rests against the overlay spring bearing 32.

The lower housing part 3 is guided with an upper region of the hollow cylindrical section 47 into the lower housing opening 45 of the housing upper part 2. The means for releasably connecting 46, 54 of the lower housing part 3 and upper housing part 2 are detachably connected to each other. The drive member 34 engages with the tip 37 in the upper housing opening 67 and is located in the recess 64 on the piston head 63 at. The piston plate 63 pushes the drive member 34 upwards and via the decoupling device 44, the lifting rod 6 is pressed against the threaded spindle 8 with the collar.

According to Fig. 7 to 14 the transmission part 19 has on the outer periphery above the toothed rim 20 with axially directed teeth a circular-cylindrical locking element 82. The locking element 82 has a toothed rim 83 with radially outwardly directed teeth. The ring gear 83 has a finer For example, the ring gear 20 is provided with 60 teeth and the ring gear 83 with 180 teeth.

In addition to the ring gear 83, a locking body 85 is arranged in a radially directed guide 84. The locking body 85 is generally cuboidal and has on the side facing the ring gear 83 a part-circular cylindrical active surface 86. The part-circular cylindrical active surface 86 is provided with a ring gear 87 with radially inwardly directed teeth. In the example, the sprocket 87 has a number of 18 teeth.

At the end of the radial guide 84 a fixedly connected to the housing 1.1 spring bearing 88 is arranged. Between spring bearing 88 and the outside of the locking body 85, a spring element 89 is arranged in the form of a conical spring. The spring element 89 presses the locking body 85 under pretension against the locking element 82 in a locking position in which the ring gear 87 is in engagement with the ring gear 83.

Further, two-armed levers 92, 93 are mounted in fixedly connected to the housing pivot bearings 90, 91 in the form of bearing eyes, which engage each with a first lever arm 94, 95 on the locking body 85. For this purpose, the locking body 85 has on the upper side a groove-shaped recess 96 in which from the underside of the first lever arms 94, 95 projecting cams 97, 98 engage. The levers 92, 93 each have a second lever arm 99, 100 which are extended towards opposite side walls 101, 102 of a housing body 103. The housing head 103 projects laterally at the level of the sprockets 20, 83 with respect to the rod-shaped housing and has a substantially oval shape in plan view.

The meshing with the ring gear 20 gear of the counter gear is disposed below the two-armed lever.

Further, in further connected to the housing 1.1 further pivot bearings 104, 105 unlocking elements 106, 107 are mounted in the form of further levers. The further levers 106, 107 are formed in this embodiment as a one-armed lever. They engage laterally in apertures of the housing head 103 and protrude laterally from the housing head 103 with an actuating portion 110, 111. The further pivot bearings 104, 105 of the further levers 106, 107 are bearing eyes into which engage portions of shafts 112, 113 projecting from the underside of the further levers 106, 107. Furthermore, the further pivot bearings 104, 105 comprise further bearing lugs, not shown, in the housing cover into which sections of the shafts 112, 113 projecting from the upper side of the further lever engage.

Furthermore, further spring elements 116, 117 are arranged in the form of leaf springs between firmly connected to the housing further spring bearings 114, 115 and the other levers 106, 107. The further spring elements 116, 117 are fixed to the inner surfaces of the further lever 106, 107. The further spring elements press the further levers 106, 107 with the actuating sections 110, 111 out of the apertures in the housing head 103 until the further levers 106, 107 bear against the limiting wall of the housing head with a stop element 118, 119 protruding from the underside.

The two-armed levers 92, 93 abut with the outer edges of their further lever arms 99, 100 on the inner sides of the further levers 106, 107.

In the housing head 103, a base plate 120 is arranged. Then the counter 23 and the counter gear 21 is mounted. The radial guide 84 and the pivot bearings 90, 91 and the bearing eyes of the further pivot bearings 104, 105 are formed in the base plate 120.

The base plate 120 is fixed by means of domes 121, 122 in holes of the housing 1.1.

Further, the base plate via snap hooks 123, 124 is connected to complementary recesses in the housing.

The embodiment of Fig. 15-17 differs from the embodiment described above in that the other levers 106, 107 are also designed as two-armed lever which contact the outer edge of the lever with a further first lever arm 125, 126. In this position, they are pressed by means of a further spring element 116, 117, which is arranged between a bearing fixedly connected to the housing and a further second lever arm 127, 128 of the further lever 106, 107.

Furthermore, sprung balls 129, 130 are integrated in the housing 1.1, which partially protrude upwards. The sprung balls 129, 130 are associated with corresponding holes 131, 132 on the undersides of the two other levers 106, 107, which receive the spring-loaded balls 129, 130 in an unlocked position.

The embodiment of Fig. 18-19 differs from the above-described embodiment in that the locking element 82 is formed as a ferromagnetic metal ring on the transmission part 19 and the locking body 85 as a magnet with circular-cylindrical active surface 86.

In all embodiments prevents or hinders in the locked position of the Fig. 7 to 11 . Fig. 15 and Fig. 18 By pressing against the actuating portion 110, 111 of an unlocking element or further lever 106, 107, the levers 92, 93 are pivoted and the locking body 85 moves in the radial direction from the locking position into the unlocked position, in the locking body 85 does not block the locking element 82. This is in Fig. 13 . 14 . 16 and 19 shown.

In the embodiment of Fig. 7-14 the further lever 106, 109 must be held in the unlocked position, so that the locking body 85 is not moved back by the spring element 89 in the locking position. In the embodiments of Fig. 15-19 holds the lock by means of the ball 129, 130, the other lever 106, 107 fixed in the unlocked position, so that it can also be relieved. Thereafter, a new interlock in the embodiment of Fig. 7-14 by relieving the further lever 106, 107 and in the embodiments of FIG Fig. 15-19 by pressing on the further second lever arm 127, 128 of the further lever 106, 107, so that the lock is released in the unlocked position. The embodiment of Fig. 18 and 19 can be realized without spring element 89, since the locking body 85 is displaced by the magnetic forces in the locked position.

In all embodiments, the unlocking can be done by pressing one of the two levers. Thus, right and left-handers have the opportunity to choose the lever that allows the simplest operation.

• Sie wird am Gehäuseoberteil 2 gegriffen.

The pipette 1 can be used as follows:

• It is gripped on the upper housing part 2.

First, the lock is released by pressing one of the unlocking elements 106, 107. Thereafter, the transmission element 9 and thus rotatably connected actuator 4 is rotatable.

A metering stroke is adjusted by rotating the actuator 4 until the meter wheels 22 indicate the desired metering volume. When turning the actuating element 4, the threaded spindle 8 is rotated about the Spindelmitnehmer 10 and axially displaced due to its threaded connection with the fixed housing upper part 2 in the spindle nut 9. At the same time, the transmission part 19 is turned over the further radial projections 15, 16 and the counter 23 is adjusted. As a result, the set axial position of the threaded spindle 8 in the upper housing part 2 and thus the metering volume at the counter 23 is read.

After adjusting the Dosiervolumens is in the embodiment of Fig. 7-14 by relieving the unlocking element 106, 107 and in the embodiments of Fig. 15-19 by actuating the further second lever arm 127, 128 of the further lever 106, 107, the locking of the locking body 85 with the transmission part 19 is restored. As a result, the transmission part 19 and thus the actuator 4 is prevented from unintentional rotation or the unintentional rotation is difficult.

Further, a pipette tip 51 is clamped on the lug 50, preferably by being pressed into a pipette tip 51, which is held in a holder.

Before sucking liquid, air is expelled from the cylinder 57 by pushing the piston 58 downward by means of the operating member 4 until the further collar 38 strikes the lower stopper body 27. Here, the lifting rod 6 moves via the decoupling device 44, the drive element 34 down and the piston 58 is pushed deeper into the cylinder 57. Due to the force between the magnet 40 and the armature 39, the decoupling device 44 does not decouple.

Thereafter, by means of the pipette 1, the lower end of the pipette tip 51 is immersed in the liquid and the desired amount is sucked into the pipette tip 51 by releasing the actuating element 4. Here, the piston spring 70 pushes the piston 58 and thus the drive element 34 and the lifting rod 6 back to the starting position, in which the collar 25 rests against the threaded spindle 8.

In this situation, the pipette is 1 in Fig. 1 . 2 . 5 . 6 and 20a shown.

Thereafter, the pipette tip 51 can be aligned with the lower end to another vessel by means of the pipette 1. By pressing the actuator 4 down the lifting rod 6 is moved down and the decoupling device 44, the drive element 34 is displaced downwards, so that the piston 58 is again moved in the cylinder 57 down. In this case, the set metering is essentially delivered. This situation is in Fig. 20b shown.

Remains remaining in the pipette tip 51 can be blown out by pressing the actuating element 4 further down under increased force. Here, the lower stopper body 27 is displaced against the action of the overstroke spring 31 in the guide slots 30 down and on the decoupling device 44, the drive element 34 further displaced downwards, which pushes the piston 58 even deeper into the cylinder 57. During the overstroke, a further overpressure is generated which pushes out residual liquid adhering to the inner wall of the pipette tip 51.

The overstroke is completed when the drive element 34 with the other collar 38 strikes the overstroke spring bearing 32, which forms the end stop. At the same time, the projections 29 reach the actuating end 78 of the discharge extension 74 or are located at a very small distance above it. This situation is in Fig. 20c shown.

Thereafter, the pipette tip 51 can be dropped. For this purpose, the actuator 4 is pressed with increased force further down. The over-stroke spring bearing 32 prevents the drive member 34 from moving further down. Due to the increased force, the magnet 40 releases from the armature 39 and the lifting rod 6 moves further down and takes the lower stopper body 27 with. The lower stopper body 27 presses with the projections 29, the discharge extension 74 to the operating ends 78 down. The Abwurfverlängerung 74 takes the discharge slide 72 with downward, which pushes the pipette tip 51 from the approach 50 with the discharge end 73.

During the discharge stroke, the piston 58 is not further moved in the cylinder 57 down. As a result, no dead volume is needed down in the cylinder 57 and the piston 58 does not hit the bottom of the cylinder 57. If the magnet 40 is released from the armature 39, the force required for the further displacement of the actuating element 4 down again is reduced. The discharge stroke is completed when the Abwurfverlängerung 74 meets a discharge stop, not shown in the housing. This situation is in Fig. 20d shown.

After releasing the actuator 4, the pipette 1 automatically returns to the initial situation of Fig. 1 . 2 . 5 . 6 and 20a back. In this case, a Abwurffeder pushes the Abwurfverlängerung 74 and thus the discharge slide 72 upwards. Further, the decoupling spring 43 pushes the lifting rod 6 with the magnet 40 upwards until the magnet 40 is held by the magnetic forces on the armature 39. Further, the overstroke spring 31 pushes the lower stopper body 27 upward until the projections 29 have arrived at the upper ends of the guide slots 30. Further, the piston spring pushes the piston 58, the drive element 34 and the decoupling device 44, the lifting rod 6 upwards until the collar 25 rests against the threaded spindle 8.

In a further variant, the decoupling unit 44, 43 can be dispensed with in order to execute the stroke, overstroke and discharge stroke. The lifting rod 6 acts directly on the conical recess 64 of the piston 58.

The upper housing part 2 can be easily connected to another housing lower part 3 to a housing in which the cylinder 57 and the piston 58 have a different cross-section. Accordingly, the same upper housing part 2 can be used for the production of pipettes 1 with different dosing volumes. Furthermore, it is possible, in the event of a defect, to easily exchange the lower housing part 3 or upper housing part 2 or, if required, to fit the upper housing part 2 with another lower housing part 3. In addition, too, too Maintenance, repair and cleaning purposes, the lower housing part 3 are easily removed from the upper housing part 2.

List of reference numbers used

1

pipette

1.1

casing

2

Housing top

3

Housing bottom

4

actuator

5

Cover of the actuating element

6

cylindrical lifting rod

7

Upper passageway

8th

screw

9

spindle nut

10

lifting body

11

Spindelmitnehmer

12

hexagon

13

hole

14

Allen

15, 16

radial projections

17, 18

groove

19

transmission part

20

Sprocket with axially directed teeth

21

Zählwerksgetriebe

22

Zählwerksräder

23

counter

24

housing cover

25

beaded waistband

26

lower front side

27

lower stop body

28

lower passageway

29

projections

30

guide slots

31

travel spring

32

Überhubfederlager

33

Through-hole

34

driving element

35

upper sleeve section

36

lower sleeve section

37

frustoconical tip

38

another bunch

39

hollow cylindrical anchor

40

hollow cylindrical magnet

41

pot

42

needle-shaped section

43

decoupling spring

44

decoupling device

45

lower housing opening

46

Means for detachable connection

47

hollow cylindrical section

48

upper hollow cone section

49

lower hollow cone section

50

conical approach

51

pipette tip

52

upper opening

53

lower opening

54

further means for detachable connection

56

connecting channel

57

cylinder

58

piston

59

O-ring

60

piston seal

61

needle-shaped extension

62

Through opening

63

piston plate

64

conical depression

65

cylindrical cap

67

upper housing opening

68

projections

69

deepening

70

piston spring

71

discarding equipment

72

ejection slide

73

discharge end

74

shedding extension

75

Abwurfstange

76

shedding ring

77

Upper ejection spring bearing

78

actuating end

79

web

80

Lower ejection spring bearing

81

ejection spring

82

locking element

83

Cog with radially outward teeth

84

radial guidance

85

locking body

86

effective area

87

Cog with radially inward teeth

88

spring camp

89

spring element

90

pivot bearing

91

pivot bearing

92

two-armed lever

93

two-armed lever

94

first lever arm

95

first lever arm

96

recess

97

cam

98

cam

99

second lever arm

100

second lever arm

101

Side wall

102

Side wall

103

housing head

104

another pivot bearing

105

another pivot bearing

106

Unlocking element (further lever)

107

Unlocking element (further lever)

110

actuating section

111

actuating section

112

wave

113

wave

114

another spring bearing

115

another spring bearing

116

another spring element

117

another spring element

118

stop element

119

stop element

120

baseplate

121

mandrel

122

mandrel

123

snap hooks

124

snap hooks

125

another first lever arm

126

another first lever arm

127

another second lever arm

128

another second lever arm

129

feathered ball

130

feathered ball

131

hole

132

hole

Claims (17)

With pipette ● a bar-shaped housing (1.1), A seat (50) for releasably holding a pipette tip (51) at the lower end of the housing (1.1), ● a displacement device comprising a displacement chamber (57) with a boundary (58) displaceable therein, ● a connecting channel (56) connecting the displacement chamber (57) to an opening in the seat (50), ● a drive device (6) coupled to the displaceable boundary (58) for displacing the displaceable boundary (58) of the displacement device, Adjustable means for limiting (8, 25, 27) the displacement of the displaceable boundary (58) by the drive device (6), ● an actuating element (4) connected to the drive device (6) and projecting out of the upper end of the housing (1.1) for controlling a displacement of the displaceable boundary (58) by displacing along an axis and adjusting the adjustable means (8, 25, 27) for limiting by turning the actuating element (4), A cylindrical transmission part (19) which is rotatably mounted in the housing (1.1) and in a certain position in the axial direction, the actuating element (4) being displaceable in an axially extended receptacle of the transmission part (19) and having means for rotationally fixed connection (15 , 16, 17, 18) is non-rotatably connected to the transmission part (19), ● first means coupled to the actuating element (4) and the adjustable means for limiting (8, 25, 27) the displacement for transmitting (11, 14) a rotational movement of the actuating element (4) to a movement for setting the adjustable means for limiting (FIG. 8, 25, 27) of the displacement, ● adjustable means for displaying (23) a dosing volume with an externally visible display (22), ● second means coupled to the transmission part (19) and the adjustable means for indicating (23) for transmitting (20, 21) a rotational movement of the transmission part (19) to a movement for setting the adjustable means for displaying (23), A circular-cylindrical locking element (82) on the outer circumference of the transmission part (19), A locking body (85) having a part-cylindrical active surface (86) which bears in the locking position on the circumference of the locking element (82), ● means for displacing (89) the locking body (85) into the locking position, ● at least one of the housing (1.1) above, with respect to the housing (1.1) movably mounted unlocking element (106, 107) and ● third means coupled to the locking body (85) and the unlocking element (106, 107) for transmitting (92, 93) movement of the unlocking element (106, 107) relative to the housing (1.1) to movement of the locking body (85) from the locking position of Locking element (82) away. A pipette according to claim 1, comprising unlocking elements (106, 107) projecting from the housing (1.1) on side walls (101, 102) of the housing (1.1) facing away from each other, each having third means for transmitting (92, 93) to the locking body (11). 85) for selectively displacing the locking body (85) away from the locking element (82) by actuating one or the other unlocking element (106, 107). A pipette according to claim 1 or 2, wherein the locking element (82) is a sprocket (83) on the periphery of the transmission part (19) with radially outwardly directed teeth and the locking body (85) on the part-cylindrical active surface (86) has a sprocket (87 ) with radially inwardly directed teeth which engage in the locking position in the teeth of the locking element (82). A pipette according to claim 1 to 3, wherein the locking element (82) is ferromagnetic and the locking body (5) is magnetic. A pipette according to claim 1 to 3, wherein the locking element (82) is ferromagnetic and the locking body (5) is magnetic. A pipette according to claim 3, wherein the locking body (85) has at least 5 and / or at most 35 teeth, further preferably at least 15 and / or at most 25 teeth. A pipette according to any one of claims 1 to 4, wherein the third means for transmitting (92, 93) comprises a two-armed lever having a first lever arm (94, 95) engaging the latch body (85) and a second lever arm (99, 100) who is either at the Unlocking element (106, 107) attacks or itself the unlocking element (106, 107). A pipette according to any one of claims 1 to 5, wherein the lever arms (94, 95, 99, 100) of the two-armed lever (92, 93) are obtuse-angled relative to each other and / or arcuate around the actuator (4). A pipette according to any one of claims 1 to 6, wherein the unlocking element (106, 107) has a further lever pivotably mounted in the housing (1.1) with a lever arm (125, 126) engaging the third means for transfer (92, 93) from the housing projecting actuating portion (110, 111). A pipette according to claim 7, wherein there are means for locking (129, 130, 131, 132) of the further lever (106, 107) in an unlocking position between the further lever (106, 107) and the housing (1.1). A pipette according to any one of claims 1 to 8, wherein the means for displacing the locking body (85) into the locking position comprises a spring element (89) supported on a spring bearing (88) integral with the housing (1.1) and the locking body (85) loaded in the locked position. A pipette according to any one of claims 1 to 9, wherein the second means for transmitting (20, 21) comprises a sprocket with axially directed teeth on the outer circumference of the transfer member (19) into which a gear of the display means (23) engages. A pipette according to any one of claims 1 to 10, wherein The drive device (6) has an axially displaceable lift rod for displacing the displaceable boundary (58) of the displacement device, ● The adjustable means for limiting (8, 25, 27) in the axial direction of the lifting rod (6) displaceable upper stop body (8), a lower stop body (27) and arranged between the upper and lower stop body stop element (25) on the circumference of the lifting rod (6) for limiting the stroke of the lifting rod, and ● the actuating element (4) is connected to the lifting rod (6). A pipette according to claim 11, wherein the upper stopper body (8) is a threaded spindle having an upper passageway (7) through which the lifting rod (6) passes and which is inserted into a spindle nut (9) fixed to the housing (1.1) ) is screwed, in which the lower stop body (27) has a lower passageway (28) through which the lifting rod (6) is extended therethrough and in which the lifting rod (6) with the stop element (25) between the upper stop body (8) and the lower stop body (27) is displaceable. Pipette according to Claim 12, in which the first means for transmitting (11, 14) are further means for non-rotatably connecting the actuating element (4) to the threaded spindle (8), which permits an axial displacement of the actuating element (4) with respect to the threaded spindle (8). allow. A pipette according to claim 13, wherein the further means for non-rotatably connecting (11, 14) actuating element (4) and threaded spindle (8) has a polygon, which engages in a complementary, axially extending extended receptacle of the actuating element (4). A pipette according to any one of claims 1 to 14, wherein one or more of the following components are wholly or partly mounted on a base plate (120) mounted in the housing (1.1): ● counter (23), ● Counter gear (21), ● locking body (85), ● lever (92, 93), ● further lever (106, 108), ● spring element (89), ● further spring element (116, 117).

Images