CN103447105A

CN103447105A - Pipette with blocking system

Info

Publication number: CN103447105A
Application number: CN2013102334731A
Authority: CN
Inventors: J·维尔默; I·温特
Original assignee: Eppendorf SE
Current assignee: Epedov Europe
Priority date: 2012-05-02
Filing date: 2013-04-28
Publication date: 2013-12-18
Anticipated expiration: 2033-04-28
Also published as: CN103447105B; EP2659978B1; EP2659978A1; PL2659978T3

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

Pipette

Technical field

The present invention relates to a kind of pipette of replaceable pipette tip.

Background technology

Pipette especially at use for laboratory in metering liquid.For this reason, pipette tip is clamped on the bearing of pipette by upper shed.The bearing great majority are the conical or columniform projections with respect to the housing of pipette, and pipette tip can be clamped on described projection by upper shed.By under shed, pipette tip can absorb and discharge liquid.Air cushion pipette (Luftpolsterpipette) comprises the discharger for air, and described discharger is connected with pipette tip phase earthing by the hole in bearing.By discharger, air cushion is moved, thereby liquid is inhaled in pipette tip or therefrom discharge.For this reason, discharger has with the discharge chamber of stop movably.Discharger normally has the movably cylindrical shell of piston in inside.

Pipette tip is disassembled and is replaced with new pipette tip from bearing after crossing.Can in the metering process of back, avoid being infected with thus.Usually pipette tip has the dismounting device for the removal pipette tip, and described dismounting device can be realized in the situation that do not contact pipette tip by push-botton operation removal pipette tip.But disposable pipette tip cost is advantageously made of plastic.

Movably stop and drive unit are coupled, and described drive unit is for making piston move at cylindrical shell.Drive unit has lifting arm, and described lifting arm can move by stop element between upper backstop and lower backstop.When starting the air intake discharge chamber, stop element is on lower backstop.When starting air is discharged from cylindrical shell, stop element is on backstop.The amount of liquid that absorbs or discharge is relevant with the stroke of stop movably also so relevant with the stroke of lifting arm.Movably the swept volume of stop is not accurately consistent with the liquid measure absorbed and discharge.Because air column is long at the effect end micro stretching of the gravity of liquid, so swept volume surpasses liquid volume.Swept volume is especially relevant with viscosity, temperature, air pressure and wettability effect with the density of liquid with the deviation of liquid volume.For example, known by WO03/033151 or US-A-3827305, by regulating the position of upper backstop, pipette is calibrated to definite metered volume.

At volume, in fixing pipette, the distance between upper backstop and lower backstop is constant.Known a kind of fixed volume pipette that comprises upper backstop from US4020698, described upper backstop is configured to the screw shell that can adjust by truing tool.

In the adjustable pipette of metered volume, the position of upper backstop is transformable.Known pipette has the upper backstop of leading screw form, and described leading screw can be regulated in the feed screw nut in being fixedly placed on housing.In order to regulate described leading screw, there is governor motion, the display unit for showing adjusted metered volume of described governor motion and counter form is coupled.

DE4335863C1 and US5,531,131 have described a kind of pipette, and in described pipette, columniform executive component stretches out and is connected with the upper end of lifting arm from housing in the above, and described lifting arm is connected with piston on bottom.Lifting arm is guided through the upper channel of leading screw and the lower channel of lower backstop.Lifting arm has the stop element of outwardly directed protuberance form, the motion of described protuberance restriction lifting arm between leading screw and lower backstop.By overcoming the defeating into executive component of back-moving spring, piston is deeper moved in cylindrical shell, until stop element abuts on lower backstop.After to the executive component unloading, due to the effect of back-moving spring, piston turns back to its initial position, and in described initial position, stop element abuts on leading screw.Adjusting device for adjusting screw has regulating sleeve, and described regulating sleeve stretches out from housing in the above, and executive component can axially move in described regulating sleeve.Regulating sleeve is rotatably supported in housing and by synchronous piece and can not be connected with the upper end of leading screw with relatively rotating.By rotating regulating sleeve, can make leading screw move together with nut, wherein, synchronous piece can axially move in the axial groove of regulating sleeve.

In addition, known pipette, wherein columniform executive component is simultaneously with the regulating element that acts on adjusting screw.For this reason, executive component can not relatively rotate with can axially movably with the upper end of leading screw, be connected.The synchronous piece of the polyhedron form on the upper end of leading screw sinks in the receptacle of complementation of executive component.Executive component is movably disposed within breach sleeve-shaped, that be rotatably supported in the drive disk assembly in housing.Executive component can not be connected with drive disk assembly by the synchronous piece of the rib form in the axial groove of outwardly directed and embedding drive disk assembly with relatively rotating.Drive disk assembly has the ring gear of the tooth that band axially stretches out on periphery in the outside, for engaging-in these teeth of a gear of the counter that shows adjusted metered volume.

Known pipette has blocking mechanism, and described blocking mechanism prevents from by mistake changing adjusted metered volume in metering process.For this reason, between the tooth of two adjacent axial sensings of the ring gear on the periphery that can be embedded in around the tooth of the axial sensing on a lever arm of the caliper lever of horizontal axis deflection drive disk assembly.Lever is pressed in this blocking device by spring.Have button for release, described button partly stretches out and is applied on another lever arm of above-mentioned lever by the face tilted in housing from housing.By button deeper is pressed in housing and can makes deviation of lever, thus described tooth from ring gear out.In this position, executive component can rotate for regulating metered volume.This locking system of the turned position of executive component has been described in EP0527170B1.

Known locking has shortcoming, and described being latched in can be destroyed by the power rotating operation element to improve in blocking device.In addition, to press down unlock button and regulate metered volume and also require great effort very much simultaneously.In addition, the wedge drive (Keilgetriebe) that operation consists of with lever button requires relative high power consumption.In addition, limited the precision of regulating metered volume in the ring gear of the engaging-in drive disk assembly of tooth.In addition, the installation of described many single parts expends.

Summary of the invention

Set out thus, task of the present invention is, a kind of pipette had the dissoluble locking of the turned position of executive component is provided, and described pipette has favourable application characteristic.

This task solves by the pipette with the described feature of claim 1.The favourable design of pipette provides in the dependent claims.

According to pipette of the present invention, have:

Shaft-like housing,

Bearing, for pipette tip can be remained on to the bottom of housing with unclamping,

Discharger with discharge chamber, described discharge chamber is included in mobile stop in this discharge chamber,

For connecting the interface channel of opening of discharge chamber and bearing,

With described mobile stop, be coupled, for the drive unit of the described mobile stop of mobile discharger,

The mechanism for restriction that can regulate, for limiting described mobile stop by the movement of drive unit,

The executive component be connected with drive unit, stretch out from the upper end of housing, for the movement by along moving of an axis, controlling described mobile stop with for by rotating described executive component, regulating the mechanism for restriction that described energy is regulated,

Columniform drive disk assembly, described drive disk assembly can support in definite Shangdi, position rotationally and vertically in housing, wherein, executive component can move in the axially extended receptacle of described drive disk assembly, and can not be connected with drive disk assembly by the mechanism for not relatively turnable connection with relatively rotating

The first mechanism be coupled with executive component and the described mechanism for moving-limiting that can regulate,

the first mechanism is for regulating the motion of the described mechanism for moving-limiting that can regulate for the rotational motion of executive component is transmitted,

The mechanism for showing that can regulate, for showing metered volume, this mechanism for showing that can regulate comprises the display that can see from the outside,

With the second mechanism that drive disk assembly and the described mechanism for demonstration that can regulate are coupled, for the rotational motion by drive disk assembly, transmitting is for regulating the motion of the described device for demonstration that can regulate,

Columniform blocking element on the neighboring of drive disk assembly,

Atretic body with the columniform acting surface of part, described acting surface abuts on the periphery of blocking element in locked position of coupler,

Be used for making atretic body to move to the mechanism of locked position of coupler,

Release element that at least one stretches out from housing, that can support with respect to housing with moving, and

The 3rd mechanism be coupled with atretic body and release element, for by release element with respect to the motion of housing transmit for atretic body from locked position of coupler out, away from the motion of blocking element.

According to pipette of the present invention, the metered volume of setting guaranteed by following manner, that is, atretic body is arranged on the periphery of columniform blocking element in locked position of coupler.The drive disk assembly that has blocking element on neighboring is fixed thus.Columniform blocking element can form dividually with the ring gear for actuation counter.In thus can be at an arbitrary position or compare in more selectable turned position and realize locking with traditional locking, in described traditional locking, blocking element embeds the ring gear for actuation counter.Thus, reduce the mistake when regulating metered volume.In addition, also make to find the locking point to become easy.The columniform acting surface of the part of atretic body can be larger than the tooth of latched lever of the prior art.Locking is more difficult like this is overcome or destroys, and the reliability of locking is improved.In addition advantageously, atretic body, blocking element and can save on the ring gear be placed in spatially for actuation counter for the 3rd mechanism that transmits motion.At this, what for the 3rd mechanism transmitted, can affect by frictional force forms with the wedge drive ground that improves operating physical force.

According to a kind of design, pipette has each release element stretched out from housing on the sidewall deviated from each other of housing, described release element is coupled by the 3rd mechanism and atretic body for transmitting respectively, in order to by operating described one or described another release element, atretic body is removed from blocking element selectively.This design is particularly advantageous when left-handed people and dexterous people use pipette, for these two kinds of people, has the release element that can easily get at available.

According to a kind of design, blocking element is ring gear on the periphery of drive disk assembly, that have the tooth radially outward pointed to, and atretic body has the ring gear of the tooth that band radially inwardly points on the columniform acting surface of described part, and the tooth of the ring gear that described atretic body has is engaged in the tooth of blocking element in locked position of coupler.In the another kind design, blocking element is ferromagnetic, and atretic body is magnet.According to the another kind design, blocking element is that checking cylinder and atretic body are brake block.First two and latter two scheme also can be used in combination.

Preferably, atretic body comprises at least five teeth and/or maximum 35 teeth, preferably includes in addition at least 15 teeth and/or maximum 25 teeth.

According to another kind, design, described have the caliper lever for the 3rd mechanism transmitted, this caliper lever comprises the first lever arm of acting on atretic body and comprises the second lever arm, described the second lever arm or act on release element or itself be release element.This design can be saved spatially and be implemented, and makes it possible to release effortlessly.Thereby, for using king-sized power to make atretic body insert the reliable especially embodiment of locking in locked position of coupler, this design is favourable.

According to the another kind design, each lever arm of caliper lever mutually tilts in obtuse angle and/or extends in the camber line around executive component.This design is conducive to save and lay spatially around drive disk assembly equally.

According to the another kind design, release element has and can be bearing in to deflection another lever in housing, and this another lever has the lever arm in the 3rd mechanism acted on for transmitting and the operation section stretched out from housing.This design can realize, by the transmission mechanism that comprises a plurality of lever arms, transmits power, and the transmission of described power makes release become easy.Thereby, for using king-sized power to make atretic body insert the reliable especially embodiment of locking in locked position of coupler, this design is favourable.

According to the another kind design, between described another lever and housing, exist for described another lever being locked to the mechanism of unlocked position.This being designed with is beneficial to only by singlehanded adjusting metered volume, because the user can unclamp described another lever and then use thumb and forefinger rotating operation element like a cork in unlocked position.

According to the another kind design, there is spring element for the mechanism that atretic body is moved to locked position of coupler, described spring element is bearing on the spring base be fixedly connected with housing and to the atretic body in locked position of coupler and loads.When release element being unloaded, spring element is fixed on atretic body in locked position of coupler.When the operation release element, the effect that atretic body overcomes spring element moves out from locked position of coupler.After to the release element unloading, spring element turns back in locked position of coupler the atretic body motion.Preferably at this spring element, also be used in during the 3rd mechanism of transmission and release element motion turn back to initial position, from described initial position, by the operation release element, can carry out release.According to a kind of preferred design, spring element is helical spring or volute spring.

According to the another kind design, there is another spring element, described another spring element is bearing on the bearing be fixedly connected with housing and in unlocked position release element is loaded.The effect that release element can overcome described another spring element is operated, and turn back to unlocked position by described spring element motion after unloading in.

In a kind of optional design, can be along two different direction operation release elements, and atretic body by the 3rd mechanism for transmitting like this and release element be coupled, make by along one of them direction operation release element, atretic body can move out also thereby can be unlocked from locked position of coupler, and pass through along another direction operation release element, atretic body can move and turn back in locked position of coupler.

Design according to another kind, have the ring gear of tooth on the neighboring of drive disk assembly, that band axially points to for the second mechanism transmitted, the gear of the described mechanism for demonstration is engaged to described tooth.Therefore this design is corresponding with traditional pipette, still, different from traditional pipette, and cylindrical blocking element forms dividually with the ring gear of the tooth that band axially points to.When cylindrical blocking element is realized to ring gear, described ring gear preferably has the number of teeth more more than the ring gear of the tooth with axial sensing.Preferably, the number of teeth of cylindrical blocking element is the axially at least twice of the number of teeth of the ring gear of the tooth of sensing of band, and being more preferably is at least three times.

According to another kind, design, driving mechanism has the axially movable lifting arm of energy, mobile stop for mobile discharger, the described mechanism for restriction that can regulate have along the axial mobile upper backstop of lifting arm, lower backstop and the periphery of lifting arm, between upper backstop and lower backstop, arrange, for the stop element of the stroke that limits lifting arm, and executive component is connected with lifting arm.According to a kind of preferred design, there is back-moving spring, described back-moving spring is bearing on the bearing be fixedly connected with housing, and the driving mechanism in initial position is loaded, and in described initial position, stop element abuts on backstop.The effect that described movably stop can overcome by the operation to executive component back-moving spring moves in discharge chamber, so that liquid is discharged from pipette tip.After to the executive component unloading, back-moving spring makes driving mechanism and therefore makes described movably stop motion turn back in initial position, so that liquid is sucked in pipette tip.

According to another kind, design, upper backstop is leading screw, this leading screw has upper channel, lifting arm is guided through described upper channel, and this leading screw is screwed in the feed screw nut be fixedly connected with housing, lower backstop has lower channel, and lifting arm extends through described lower channel, and lifting arm can move together with stop element between upper backstop and lower backstop.Alternatively, substitute leading screw and use tooth bar, backstop on described tooth bar can and have by the gear drive adjusting on bottom.

These designs of drive unit and adjustable mechanism for moving-limiting are simple in configuration aspects, and can realize regulating exactly metered volume.

According to the another kind design, for the first mechanism transmitted, be the other mechanism for executive component can not be connected with leading screw with relatively rotating, described other mechanism allows executive component to move axially with respect to leading screw.By this design assurance of the first mechanism for transmitting, the rotational motion of executive component can be delivered to leading screw, and executive component can move axially with respect to leading screw.

According to another kind design, described have polyhedron for the other mechanism that executive component can not be connected with leading screw with relatively rotating, described polyhedron be embedded into executive component complementation, in axially extended receptacle.

According to another kind design, one or more completely or partially being arranged on the soleplate be fixed in housing in following member: counter, counter transmission mechanism, atretic body, lever, release element, spring element, other spring element.These members can pre-installation on soleplate, and can equip for pipette the soleplate of described pre-installation.Realize thus installing sealing.

Preferably, according to pipette of the present invention, be hand-held pipette.Relate to a kind of pipette that user's one hand can be arrested and operate when moving liquid at this.Preferred described pipette is mechanically operated pipette.Also possible in principle, utilize electric driver or there is the mechanical actuation device of supporting by the power of electric driver (servo drive) to form pipette.

The accompanying drawing explanation

Below by the accompanying drawing of an embodiment, the present invention is described in detail.In the accompanying drawings:

Fig. 1 illustrates the profilograph according to pipette of the present invention;

Fig. 2 illustrates the amplification profilograph on the top of identical pipette;

Fig. 3 illustrates along the amplification profile of III-III line in Fig. 2;

Fig. 4 illustrates the amplification detail view IV of Fig. 2;

Fig. 5 illustrates the amplification profilograph of the bottom of identical pipette;

Fig. 6 illustrates the amplification profilograph of the bottom of identical pipette, wherein there is no lifting body;

Fig. 7 in the situation that case lid is removed, at the drive disk assembly that comprises counter and locked position of coupler from pipette body case shown in top and the perspective view observed from the side sideling;

Fig. 8 illustrates another perspective view of identical set;

Fig. 9 is at the drive disk assembly of the parts that comprise counter and blocking device from pipette body case shown in top and the perspective view observed from the side sideling;

Figure 10 is comprising the parts of counter and the drive disk assembly of blocking device sideling shown in perspective view top and that observe from the side;

Figure 11 is at the drive disk assembly that comprises blocking device shown in the partial view of the amplification of observing from above;

Figure 12 is at counter and blocking device shown in the partial view of the amplification of observing from below sideling;

Figure 13 is sideling from comprising the drive disk assembly of the parts of counter and the blocking device released state shown in top and the part perspective view observed from the side;

The drive disk assembly of the blocking device of Figure 14 in shown in the partial view of the amplification of observing from above, being included in released state;

Figure 15 sideling from the drive disk assembly of the parts of the variant of the parts that comprise counter shown in top and the perspective view observed from the side and blocking device,

Figure 16 from the member of Figure 15 shown in perspective view top and that observe from the side, does not wherein comprise operating knob sideling;

Figure 17 in the situation that case lid is removed, at the member of the Figure 15 in released state from pipette body case shown in top and the perspective view observed from the side sideling;

Figure 18 in the situation that case lid is removed, at the drive disk assembly of the parts of the another kind of variant of the parts that comprise counter from pipette body case shown in top and the perspective view observed from the side and interlocking position sideling;

Figure 19 is in identical layout shown in identical perspective view, wherein release of blocking mechanism;

Figure 20 a to 20d illustrate respectively identical pipette before the operating operation element (Figure 20 a), after carrying out the metering stroke fully and carry out (Figure 20 b) before overtravel, (Figure 20 c) after the execution overtravel and before the removal pipette tip, the part profilograph of (Figure 20 d) after the removal pipette tip.

The specific embodiment

In this application, appellation "up" and "down", " on " and " under " and " level " and " vertically " reference is the orientation of pipette when housing points to straight down together with bearing.In this orientation, the pipette tip be arranged on bearing can be aligned in the container under it, in order to draw or discharge liquid.

According to Fig. 1 and 2, the housing 1.1 that pipette 1 has is shaft-like, that be configured as handle, comprise housing top 2 and lower housing portion 3.Housing top 2 forms driver element together with all contained parts, and lower housing portion 3 forms deliverying unit together with all contained parts.The executive component 4 of cylindrical button-shape stretches out from housing top 2 in the above.Executive component 4 can axially movably and be rotatably supported in housing top 2.

Executive component 4 is by covering being screwed on cylindrical lifting arm 6 in 5.Lifting arm 6 is conducted through the upper channel 7 of leading screw 8 in housing top 2.Leading screw 8 is screwed in housing top 2 in the internal thread that remains on the feed screw nut 9 in definite position.

Feed screw nut 9 is fixedly connected with the lifting body 10 in being fixed on housing top 2.Lifting body 10 is columniform basically, and be feed screw nut 9, be screwed into the support of lifting arm 6 directed in leading screw 8 wherein and leading screw.When pipette is installed, these members and other member are preloaded on lifting body 10, and the lifting body 10 that is equipped with these members is installed in housing top 2, so that lifting body remains in housing top 2 regularly.For this reason, lifting

body

10 and 2 locking location, housing top.Also possible in principle, the member pre-installation on lifting body 10 is directly installed in housing top 2.For this reason, housing top 2 can be configured according to lifting body 10 in inside.

Leading screw 8 has the screw synchronous part 11 that can not be connected with it in the above with relatively rotating.Screw synchronous part 11 has the hexagon 12 with centre bore 13 on periphery.Hexagon 12 is embedded in the interior hexagon 14 of executive component 4.

Executive component 4 is provided with two just relative radial protrusions 15,16 each other below, and described radial protrusion is protruding.Preferably have 4 radial protrusions 15,16.Radial protrusion 15,16 is embedded in the axially extended

groove

17,18 on the inboard of drive disk assembly 19 of hollow cylinder, and described drive disk assembly is rotatably supported in housing top 2.Drive disk assembly 19 has ring gear 20 in the above on periphery, the gear engagement of described ring gear and counter transmission mechanism 21, and a plurality of counter wheels 22 that are arranged side by side on horizontal axis of described counter transmission mechanism actuation counter 23.Counter 23 is fixed on housing top.Counter wheel 22 has respectively 0 to 9 numeral.With reference to figure 1 in the end the counter wheel 22 of face by counter transmission mechanism 21, driven.Each counter wheel 22 that is arranged in side is rotated further respectively a numeral, when the counter wheel that is arranged in their back is transitioned into 0 from 9.

Above counter 23, housing top 2 has the case lid 24 with window, can read the numeral of counter wheel 22 by described window.

Below leading screw 8, the flange 25 of protuberance form is set on lifting arm 6 as stop element.Abut in by flange 25 on the lower surface 26 of leading screw 8, limit moving up of lifting arm 6, described end face forms the upper backstop of flange 25.

Below feed screw nut 9, disk-shaped lower backstop 27 is arranged in lifting body 10 basically.Lower backstop 27 has bowl-shape recess, in this recess at center arrangement lower channel 28.In addition, lower backstop 27 has a plurality of (for example three or four) equably around each projection 29 of radially outward stretching out of the circumferential distribution of lower backstop.

Lower backstop 27 is guiding in the axially extended guide slit 30 of lifting body 10 on each projection 29.This is also shown in Fig. 3.Lower backstop can move up, until each projection 29 abuts on the upper end of guide slit 30.

Below lower backstop 27, be configured to helical spring overtravel spring 31 and be arranged in lifting body 10.The overtravel spring abuts on the downside of lower backstop 27 in the above.Overtravel spring 31 is bearing on the overtravel spring base 32 that is arranged in housing top 2 and is fixedly connected with it below.

Overtravel spring base 32 forms by the ring with L shaped cross section, and wherein, the horizontal sides of L shaped profile is surrounded the central through hole 33 of overtravel spring base 32.Overtravel spring 31 is bearing on the horizontal sides of L shaped profile and is surrounded by vertical limit in side.Overtravel spring 31 in the situation that preload by projection 29, lower backstop 27 tops are pressed onto on the upper end of guide slit 30.

Below lower backstop 27, with the driving element 34 with the coaxially directed form of sleeve of lifting arm 6, be arranged in lifting body 10.Driving element 34 has upper bush section 35 and lower sleeve section 36, and wherein, the internal diameter of upper bush section 35 and external diameter are larger than lower sleeve section 36.Lower sleeve section 36 has the tip 37 of truncated cone shape below.

On the top edge of upper bush section 35, exist that another radially outward stretches out, around flange 38.The external diameter of upper bush section 35 is less than the internal diameter of the through hole 33 of overtravel spring base 32, thereby upper bush section 35 and lower sleeve section 36 can import in through hole 33.The external diameter of described another flange 38 surpasses the internal diameter of through hole 33, thereby driving element 34 can not pass through through hole 33 fully.Overtravel spring base 32 forms end stop, and described another flange 38 forms the end stop element, the downward movement of their restriction driving elements 34.

In upper bush section 35, arrange the armature 39 (Anker) of the hollow cylinder of being made by ferromagnetic material in the above.In upper bush section 35, at the magnet 40 of described armature arranged beneath hollow cylinder.It below described magnet, is the tank shape section 41 that receives magnet 40.Armature 39 has interference fit (Presssitz) in upper bush section 35.Lifting arm 6 extends through the centre bore of armature 39 movably.Below armature, lifting arm 6 has the aciculiform section 42 that diameter reduces.Magnet 40 and tank shape section 41 are bearing on aciculiform section 42.Preferably, magnet 40 and tank shape section 41 are fixed on aciculiform section 44, and its mode is for example that magnet and tank shape section have interference fit.In addition, magnet 40 is bearing on the convex shoulder of lifting arm in the above, and aciculiform section 44 be take this convex shoulder exactly as initial.

Below annular disk 41, be configured to helical spring decoupling zero spring 43 and guide on aciculiform section 42, described decoupling zero spring is bearing on the bottom 43 of lower sleeve section 36 below.Armature 39, magnet 40 and decoupling zero spring 43 are members of decoupling device 44.

According to Fig. 1,2,5 and 6, housing top 2 below except having lower house opening 45 on inner rim, also be provided with do not add detailed description, the mechanism 46 for releasably being connected with other mechanism, described other mechanism is for releasably connecting lower housing portion 3.

Lower housing portion 3 has open circles shell of column 47 in the above, short, upper hollow conical section 48 that have large coning angle is connected on this open circles shell of column below, long, lower hollow cone section 49 that have the roundlet cone angle is connected to again on hollow conical section below, and described lower hollow cone forms running-on 50 (Ansatz) conical, for clamping pipette tip 51 with its bottom.It is conical that clamped pipette tip 51 is equally basically, has the under shed 53 that installs to the upper shed 52 on running-on 50 and pass through for liquid for cover.Upper shed 52 fundamentally is greater than under shed 53, and pipette tip 51 is tapered from the upper shed to the under shed.

The open circles shell of column 47 of lower housing portion 3 is provided with the other mechanism for releasable connection 54 that does not add detailed description in the above on periphery, described mechanism is suitable with the mechanism 46 for releasably being connected housing top 2, so that lower housing portion 3 releasably is connected with housing top 2.Suitable mechanism 46,54 for releasably connecting housing top 2 and lower housing portion 3 has been described in DE102004003434B4.In this respect with reference to DE102004003434B4 and US2005/155438A1, and in this its content is adopted the application.

Lower hollow cone section 49 has in the above stretches out the extension 55 that surpasses hollow conical section 48 in lower housing portion 3.

Lower hollow cone section 49 has interface channel 56, and described interface channel makes the upper surface of extension 55 be connected with the lower surface of running-on 50.

Arrange in lower housing portion 3 and comprise cylindrical shell 57 and the layout of mobile piston 58 in cylindrical shell.Cylindrical shell 57 inserts in interface channel 56 and therein by being pressed into or being adhesively fixed with lower area.Below, cylindrical shell 57 is by relative interface channel 56 sealings of O shape ring 59.

Piston 58 has piston seal 60 on periphery, and described piston seal is at inner sealing cylindrical shell 57.Below piston seal 60, piston 58 has the extension 61 of aciculiform, and described extension can guide in the through hole 62 of bottom of cylindrical shell 57 and in interface channel 56, to reduce dead volume.Cylindrical shell 57 and piston 58 are vertically-oriented.In the above, the piston plate 63 of piston 58 supporting horizontal orientations, described piston plate has the conical recess 64 of vertical orientation at center, for the tip 37 of receiving driving mechanism 34.

Lower housing portion 3 has the seal cover 65 with the tank shape of columniform or conical outer cover in the above.The bottom of seal cover 65 is arranged in the top of piston plate 63, and has the upper shell opening 67 at center, by this upper shell opening, can get at from the outside piston plate 63.Seal cover 65 has outwardly directed protruding 68 on the edge of its outer cover, and described projection buckles in the corresponding recess 69 of open circles shell of column 47 of lower housing portion 3.

The movement made progress of the bottom limited piston 58 of seal cover 65.Be configured to helical spring, be bearing on extension 55 below and the piston spring 70 that is bearing in the above on the downside of piston plate 63 piston 58 is pre-tensioner to the downside of seal cover 65.

In addition, pipette 1 has dismounting device 71.Dismounting device 71 comprises the removal sliding part 72 be arranged on lower housing portion 3.Removal sliding part 72 has the profile be complementary with profile open circles shell of column 47, hollow cone section 49 upper hollow conical section 48 and lower.The removal sliding part has the removal end 73 of annular below.Removal end 73 is upwards shifted onto on lower housing portion 3 in the position of the removal sliding part 72 shown in Fig. 1 as far as possible far, thereby exposes for the running-on 50 that is set with pipette tip 51.

Removal sliding part 72 is connected with removal extension 74 in the above.Described removal extension comprises three vertical removal bars 75, and described removal bar is connected with the top edge of removal sliding part 72.Removal bar 75 is evenly distributed on the top edge of removal sliding part 72.Removal bar 75 below by the first buckle bindiny mechanism with unload division ring 76 and be connected, the described division ring that unloads is connected with the top edge of removal sliding part 72 by the second buckle bindiny mechanism.Hold certain distance with unloading division ring 76, each removal bar 75 in the above on the inner rim of described removal bar the upper removal spring base 77 by annular interconnect.Upper removal spring base 77 has L shaped cross section, wherein, the horizontal sides of cross section below overtravel spring base 32 in abutting connection with through hole 33.Upper removal spring base 77 vertical around limit point under.

Removal bar 75 has operative end 78 in the above.

Removal extension 74 or removal bar 75 extend in housing top 2 through shell nozzle 45.Abut on the downside of overtravel spring base 32 movement made progress of restriction removal extension 74 by upper removal spring base 77.

Below upper removal spring base 77, stretch out three braces 79 from 2 inboards, housing top, described brace is arranged to be evenly distributed on inner rim, and passes the space of lifting body 10.This is especially shown in Figure 4.Brace 79 forms lower removal spring base 80.Be configured to helical spring removal spring 81 in the situation that preload is arranged between removal spring base 77 and lower removal spring base 80, and upwards push dismounting device 71, thereby upper removal spring base 77 abuts on overtravel spring base 32.

Lower housing portion 3 utilizes the upper area of open circles shell of column 47 to be directed in the shell nozzle 45 on housing top 2.For releasably connecting lower housing portion 3, with the mechanism 46,54 on housing top 2, releasably interconnect.Driving mechanism 34 is embedded in upper shell opening 67 with most advanced and sophisticated 37, and abuts on piston plate 63 in recess 64.Piston plate 63 is upwards pressed driving mechanism 34, and, by decoupling device 44, lifting arm 6 is pressed onto on leading screw 8 with the flange top.

According to Fig. 7 to 14, above the ring gear 20 of the tooth that drive disk assembly 19 axially points at band on neighboring, there is columniform blocking element 82.Blocking element 82 has the ring gear 83 of the tooth that band radially outward points to.The division ratio ring gear 20 of ring gear 83 thinner.For example, ring gear 20 is provided with 60 tooth ring gears 83 and is provided with 180 teeth.

On the side of ring gear 83, radial finger to guide part 84 in arrange atretic body 85.Atretic body 85 is rectangular parallelepiped shape normally, and has the columniform acting surface 86 of part on the side towards ring gear 83.The columniform acting surface 86 of this part is provided with the ring gear 87 of the tooth that band radially inwardly points to.In the present embodiment, ring gear 87 has 18 teeth.

Be furnished with the spring base 88 be fixedly connected with housing 1.1 on the end of guide part 84 radially.Arrange the spring element 89 with the volute spring form between the outside of spring base 88 and atretic body 85.Spring element 89 is in the situation that during preload is pressed into locked position of coupler to atretic body 85 towards blocking element 82, ring gear 87 in described locked position of coupler with ring gear 83 in engagement.

In addition,

caliper lever

92,93 is bearing in the turntable bearing be fixedly connected with

housing

90,91 of bearing insert (Lageraugen) form, and described lever acts on atretic body 85 with the

first lever arm

94,95 respectively.For this reason, atretic body 85 has the space 96 of flute profile on upside, and the

cam

97,98 stretched out from the downside of the

first lever arm

94,95 embeds described

spaces.Lever

92,93 has respectively the second lever arm 99,100, and described the second lever arm extends towards the sidewall of putting toward each other 101,102 of case top 103.Case top 103 is stretched out in side with respect to shaft-like housing and have a basically oval shape on top view at ring gear 20,83 residing horizontal planes.

The counter transmission mechanism be arranged in the below of caliper lever with ring gear 20 meshed gears.

In addition, the release element 106,107 with other lever form is bearing in the other turntable bearing 104,105 be fixedly connected with housing 1.1.Described other lever 106,107 is configured to single-arm lever in the present embodiment.Described single-arm lever embeds in the breach of case top 103 in side, and from case top 103, stretches out in side with operation section 110,111.The other turntable bearing the 104, the 105th of described other lever 106,107, bearing insert, the section that the downside from described other lever 106,107 of axle 112,113 stretches out embeds described bearing insert.In addition, described other turntable bearing 104,105 comprises unshowned other bearing insert in case lid, and the section that the upside from described other lever of axle 112,113 stretches out is embedded into described bearing insert.

In addition, arrange spring element 116,117 other, the leaf spring form between the other spring base 114,115 be fixedly connected with housing and described other lever 106,107.Described other spring element 116,117 is fixed on the inner surface of described other lever 106,107.By operation section 110,111, described other spring element is squeezing out in the described other through hole of lever 106,107 from case top 103, until described other lever 106,107 abuts in the interface wall of case top with the stop element 118,119 stretched out from downside.

The external margin of

caliper lever

92,93 by their other lever arm 99,100 abuts on the inboard of described other lever 106,107.

Arrange soleplate 120 in case top 103.Counter 23 sum counter transmission mechanisms 21 are installed on soleplate.The bearing insert of radially-directed section 84 and turntable bearing 90,91 and other turntable bearing 104,105 is formed in soleplate 120.

Soleplate 120 is fixed in the hole of housing 1.1 by axle 121,122.

In addition, soleplate is connected with the space of complementation in housing by grab 123,124.

Embodiment shown in Figure 15～17 is with the difference of described embodiment before, and other lever 106,107 is to be configured to the caliper lever equally, and described caliper lever is by the external margin of another the first lever arm 125,126 engagement levers.Described other lever is pressed onto in this position by other spring element 116,117, and described spring element is arranged between another second lever arm 127,128 of the bearing that is fixedly connected with housing and other lever 106,107.

In addition, the spheroid be spring loaded 129,130 partly protruded upward is incorporated in housing 1.1.Spheroid 129,130 configurations that are spring loaded are to the hole 131,132 of the correspondence on the downside of two other levers 106,107, and the spheroid 129,130 be spring loaded is received in described hole in unlocked position.

Embodiment shown in Figure 18～19 is with the difference of described embodiment before, and blocking element 82 is configured to the ferromagnetic metal ring on drive disk assembly 19, and atretic body 85 is configured to the magnet with the columniform acting surface 86 of part.

In whole forms of implementation, in the blocking device of Fig. 7 to 11, Figure 15 and Figure 18, atretic body 85 preventions hinder in other words drive disk assembly 19 and rotate.By the capable of being unlocked by pressing element operation section 110,111 of other lever 106,107 in other words, make

lever

92,93 deflections, and atretic body 85 radially out moves to unlocked position from blocking device, in described unlocked position, atretic body 85 does not block blocking element 82.This is shown in Figure 13,14,16 and 19.

In the embodiment shown in Fig. 7～14, other lever 106,107 remains in unlocked position, thus atretic body 85 can the effect campaign back locking device because of spring element 89 in.In the embodiment shown in Figure 15～19, lockable mechanism is fixed in unlocked position other lever 106,107 by spheroid 129,130, thereby described other lever also can be unloaded.Afterwards, in the embodiment of Fig. 7～14 by unloading other lever 106,107 and re-execute locking by lower another second lever arm 127,128 by other lever 106,107 in the embodiment of Figure 15～19, thereby remove the locking in blocking device.Figure 18 and 19 form of implementation also can realize even without spring element 89, because atretic body 85 is in the effect of magnetic force is moved to blocking device.

Can carry out release by operating one of two levers in whole embodiment.Therefore, for lefthanded and dexterous people, there is the possibility select the lever that can realize shirtsleeve operation.

Can use as follows pipette 1:

Pipette is booked on housing top 2.

At first, cancel locking by one in operation release element 106,107.Afterwards, drive disk assembly 19 with its executive component that can not be connected 4, can be rotated with relatively rotating.

Regulate the metering stroke by rotating operation element 4, until counter wheel 22 shows the metered volume of expectation.When rotating operation element 4, leading screw 8 by screw synchronous part 10, rotate and based on this leading screw be fixed on housing top 2 in feed screw nut 9 between be threaded and moved axially.At this, screw synchronous part 10 slides in the interior hexagon of executive component 4.Simultaneously, by other radial protrusion 15,16, rotate drive disk assembly 19 and regulate counter 23.Accordingly, the axial location that leading screw 8 regulates in housing top 2 can be read and therefore the metered volume on counter 23 can be read.

After setting metered volume, pass through unloading blocking element 106,107 in the embodiment shown in Fig. 7～14, and by operating another second lever arm 127,128 of other lever 106,107, regenerate the locking between atretic body 85 and drive disk assembly 19 in the embodiment shown in Figure 15～19.Prevent from thus by mistake rotating drive disk assembly 19 and therefore rotating operation element 4 by mistake, or make to rotate unintentionally the difficulty that becomes.

In addition, pipette tip 51 is sandwiched on running-on 50, and its mode is preferably, and running-on is pressed in support in ready pipette tip 51.

Before imbitition, by by the downward extrusion piston 58 of executive component 4 until another flange 38 is encountered lower backstop 27, air is discharged from cylindrical shell 57.Here, lifting arm 6 moves downward driving element 34 by decoupling device 44, and piston 58 deeper is pressed in cylindrical shell 57.At this, due to the power between magnet 40 and armature 39, decoupling device 44 not decoupling zeros.

Then, by pipette 1, the bottom of pipette tip 51 is immersed in liquid, and, by releasing operation element 4, the liquid of intended volume is inhaled in pipette tip 51.At this moment, piston spring 70 by piston 58 and therefore driving element 34 and lifting arm 6 push back original position, in described original position, flange 25 abuts on leading screw 8.

Fig. 1,2,5,6 and 20a in pipette 1 illustrate in this case.

Afterwards, by pipette 1, pipette tip 51 can point to another container with bottom.By depressing executive component 4, lifting arm 6 is moved downward, and, by decoupling device 44, driving element 34 is moved down, thereby piston 58 is moved downward again in cylindrical shell 57.Here, the amount of the metering of setting is discharged from basically.This situation is shown in Figure 20 b.

Continue downward press operation element 4 by the power effect to improve, the residue in pipette tip 51 can be drained.At this, lower backstop 27 overcomes acting in guide slit 30 of overtravel spring 31 and moves down, and driving element 34 continues to move down by decoupling device 44, and this driving element also deeper pushes piston 58 in cylindrical shell 57.When overtravel, produce other overvoltage, this residual liquid of crossing on the inwall that pressure handle sticks to pipette tip 51 extrudes.

When driving element 34 encounters by another flange 38 the overtravel spring base 32 that forms end stop, overtravel finishes.Simultaneously, projection 29 arrive the operative end 78 of removal extensions 74 or with very little interval on this operative end.This situation is shown in Figure 20 c.

Afterwards, but removal pipette tip 51.For this reason, continue downward press operation element 4 with the power effect improved.Overtravel spring base 32 stops driving element 34 to continue to move downward.By the power improved, magnet 40 separates with armature 39, and lifting arm 6 continues to move downward and drives lower backstop 27.Lower backstop 27 with the projection 29 on operative end 78 to pressing down removal extension 74.Removal extension 74 drives removal sliding part 72 and together moves downward, and described removal sliding part extrudes pipette tip 51 by removal end 73 from running-on 50.

In the removal stroke, piston 58 no longer continues to move downward in cylindrical shell 57.Therefore, do not need below dead volume in cylindrical shell 57, and piston 58 is not encountered the bottom of cylindrical shell 57.If magnet 40 separates with armature 39, executive component 4 continues to move downward needed power consumption and can again reduce.When removal extension 74 is encountered the unshowned removal backstop in housing, the removal stroke finishes.This situation is shown in Figure 20 d.

After unclamp operation element 4, pipette 1 automatically return to Fig. 1,2,5,6 and 20a shown in initial position.At this moment, the removal spring is upwards pressed removal extension 74 and so removal sliding part 72.In addition, decoupling zero spring 43 is upwards pressed lifting arm 6 and magnet 40, until magnet 40 is fixed on armature 39 by magnetic force.In addition, overtravel spring 31 is upwards depressed backstop 27, until projection 29 reaches the upper end of guide slit 30.In addition, piston spring is upwards pressed piston 58, driving element 34 and is upwards pressed lifting arm 6 by decoupling device 44, until flange 25 abuts on leading screw 8.

In another kind of scheme, in order to carry out stroke, overtravel and removal stroke, can cancel and use decoupling device 44,43.Lifting arm 6 direct effects are to the conical recess 64 of piston 58.

Housing top 2 can be connected to become housing with another lower housing portion 3 simply, and in described housing, cylindrical shell 57 and piston 58 have another kind of cross section.Correspondingly, identical housing top 2 can be for the manufacture of the pipette 1 with different metered volume.In this external failure situations, can easily change lower housing portion 3 or housing top 2, or when needed, can give housing top 2 another lower housing portion 3 of equipment.In addition, for maintenance, repair and cleaning purpose, lower housing portion 3 can easily be taken off from housing top 2.

Reference numerals list

1 pipette

1.1 housing

2 housing tops

3 lower housing portion

4 executive components

The lid of 5 executive components

6 cylindrical lifting arms

7 upper channels

8 leading screws

9 feed screw nuts

10 lifting bodies

11 screw synchronous parts

12 hexagons

13 holes

14 interior hexagons

15,16 radial protrusions

17,18 grooves

19 drive disk assemblies

The ring gear of the tooth that 20 bands axially point to

21 counter transmission mechanisms

22 counter wheels

23 counters

24 case lid

The flange of 25 protuberance forms

26 lower surfaces

27 times backstops

28 lower channels

29 projections

30 guide slit

31 overtravel springs

32 overtravel spring bases

33 through holes

34 driving elements

35 upper bush sections

36 lower sleeve sections

37 truncated-cone shaped tip

38 another flanges

The armature of 39 hollow cylinders

The magnet of 40 hollow cylinders

41 tank shape sections

42 aciculiform sections

43 decoupling zero springs

44 decoupling devices

45 lower house openings

46 mechanisms for releasably connecting

47 open circles shell of columns

Hollow conical section on 48

49 times hollow cone sections

50 is conical pullover

51 pipette tips

52 upper sheds

53 under sheds

The 54 other mechanisms for releasably connecting

56 interface channels

57 cylindrical shells

58 pistons

59 O shape rings

60 piston seals

The extension of 61 aciculiforms

62 through holes

63 piston plates

64 conical recesses

65 cylindrical seal lids

67 upper shell openings

68 projections

69 recesses

70 piston springs

71 dismounting devices

72 removal sliding parts

73 removal ends

74 removal extensions

75 removal bars

76 unload division ring

Removal spring base on 77

78 operative end

79 braces

80 times removal spring bases

81 removal springs

82 blocking elements

83 ring gears with radially outer tooth

84 radially-directed sections

85 atretic bodies

86 acting surfaces

The ring gear of the tooth that 87 bands radially inwardly point to

88 spring bases

89 spring elements

90 turntable bearings

91 turntable bearings

92 caliper levers

93 caliper levers

94 first lever arms

95 first lever arms

96 spaces

97 cams

98 cams

99 second lever arms

100 second lever arms

101 sidewalls

102 sidewalls

103 case top

104 other turntable bearings

105 other turntable bearings

106 release elements (other lever)

107 release elements (other lever)

110 operation sections

111 operation sections

112 axles

113 axles

114 other spring bases

115 other spring bases

116 other spring elements

117 other spring elements

118 stop elements

119 stop elements

120 soleplates

121 axles

122 axles

123 grabs

124 grabs

125 another first lever arms

126 another first lever arms

127 another second lever arms

128 another second lever arms

129 spheroids that are spring loaded

130 spheroids that are spring loaded

131 holes

132 holes

Claims

1. pipette has:

Shaft-like housing (1.1),

Bearing (50), for pipette tip (51) can be remained on to the bottom of housing (1.1) with unclamping,

Discharger with discharge chamber (57), described discharge chamber is included in mobile stop (58) in this discharge chamber,

For the interface channel (56) of the opening that connects discharge chamber (57) and bearing (50),

With described mobile stop (58), be coupled, for the drive unit (6) of the described mobile stop (58) of mobile discharger,

The mechanism (8,25,27) for restriction that can regulate, for limiting described mobile stop (58) by the movement of drive unit (6),

The executive component (4) be connected with drive unit (6), stretch out from the upper end of housing (1.1), for the movement of the described mobile stop of mobile control (58) by along an axis with for by rotating described executive component (4), regulating the described mechanism (8,25,27) for restriction that can regulate

Columniform drive disk assembly (19), described drive disk assembly can support in definite Shangdi, position rotationally and vertically in housing (1.1), wherein, executive component (4) can move in the axially extended receptacle of described drive disk assembly (19), and can not be connected with drive disk assembly (19) by the mechanism for not relatively turnable connection (15,16,17,18) with relatively rotating

The first mechanism (11,14) be coupled with executive component (4) and the described mechanism for moving-limiting (8,25,27) that can regulate, this first mechanism is for transmitting the rotational motion of executive component (4) motion for the mechanism for moving-limiting (8,25,27) for regulating described energy adjusting

The mechanism (23) for showing that can regulate, for showing metered volume, this mechanism for showing that can regulate comprises the display (22) that can see from the outside,

The second mechanism (20,21) be coupled with drive disk assembly (19) and the described mechanism (23) for showing that can regulate, be used for the rotational motion of drive disk assembly (19) is transmitted to the motion for the device (23) for demonstration for regulating described energy adjusting

Columniform blocking element (82) on the neighboring of drive disk assembly (19),

Have the atretic body (85) of the columniform acting surface of part (86), described acting surface abuts on the periphery of blocking element (82) in locked position of coupler,

Be used for making atretic body (85) to move to the mechanism (89) of locked position of coupler,

Release element (106,107) that at least one stretches out from housing (1.1), that can support with respect to housing (1.1) with moving, and

The 3rd mechanism (92 be coupled with atretic body (85) and release element (106,107), 93), for by release element (106,107) with respect to the motion of housing (1.1) transmit for atretic body (85) from locked position of coupler out, away from the motion of blocking element (82).

2. pipette according to claim 1, it is characterized in that, pipette has each release element (106,107) stretched out from housing (1.1) on the sidewall deviated from each other (101,102) of housing (1.1), described release element is respectively by the 3rd mechanism (92 for transmitting, 93) be coupled with atretic body (85), in order to by operating described one or described another release element (106,107), atretic body (85) is removed from blocking element (82) selectively.

3. pipette according to claim 1 and 2, it is characterized in that, blocking element (82) is ring gear (83) on the periphery of drive disk assembly (19), that have the tooth radially outward pointed to, and atretic body (85) has the ring gear (87) of the tooth that band radially inwardly points on the columniform acting surface of described part (86), and the tooth of the ring gear that described atretic body has is engaged in the tooth of blocking element (82) in locked position of coupler.

4. according to the described pipette of any one in claims 1 to 3, it is characterized in that, blocking element (82) is ferromagnetic, and atretic body (5) is magnetic.

5. according to the described pipette of any one in claims 1 to 3, it is characterized in that, blocking element (82) is ferromagnetic, and atretic body (5) is magnetic.

6. pipette according to claim 3, is characterized in that, atretic body (85) comprises at least 5 teeth and/or maximum 35 teeth, preferably includes in addition at least 15 teeth and/or maximum 25 teeth.

7. according to the described pipette of any one in claim 1 to 4, it is characterized in that, described have the caliper lever for the 3rd mechanism (92,93) transmitted, this caliper lever comprises the first lever arm (94,95) acted on atretic body (85) and comprises the second lever arm (99,100), described the second lever arm or to act on release element (106,107) upper or itself be release element (106,107).

8. according to the described pipette of any one in claim 1 to 5, it is characterized in that, each lever arm of caliper lever (92,93) (94,95,99,100) mutually tilts in obtuse angle and/or extends in the camber line around executive component (4).

9. according to the described pipette of any one in claim 1 to 6, it is characterized in that, release element (106,107) has and can be bearing in to deflection another lever in housing (1.1), and this another lever has the lever arm (125,126) in the 3rd mechanism (92,93) acted on for transmitting and the operation section (110,111) stretched out from housing.

10. pipette according to claim 7, it is characterized in that, exist between described another lever (106,107) and housing (1.1) for described another lever (106,107) being locked to the mechanism (129,130,131,132) of unlocked position.

11. according to the described pipette of any one in claim 1 to 8, it is characterized in that, have spring element (89) for the mechanism that atretic body (85) is moved to locked position of coupler, described spring element is bearing on the spring base (88) be fixedly connected with housing (1.1) and the atretic body in locked position of coupler (85) is loaded.

12. according to the described pipette of any one in claim 1 to 9, it is characterized in that, the second mechanism (20,21) that is used for transmitting has the ring gear of tooth on the neighboring of drive disk assembly (19), that band axially points to, and the gear of the described mechanism (23) for demonstration is engaged to described tooth.

13. according to the described pipette of any one in claim 1 to 10, it is characterized in that,

Driving mechanism (6) has the axially movable lifting arm of energy, for the mobile stop (58) of mobile discharger,

The described mechanism (8,25,27) for restriction that can regulate have along the axial mobile upper backstop (8) of lifting arm (6), lower backstop (27) and the periphery of lifting arm (6), between upper backstop and lower backstop, arrange, for the stop element (25) of the stroke that limits lifting arm, and

Executive component (4) is connected with lifting arm (6).

14. pipette according to claim 11, it is characterized in that, upper backstop (8) is leading screw, this leading screw has upper channel (7), lifting arm (6) is guided through described upper channel, and this leading screw is screwed in the feed screw nut (9) be fixedly connected with housing (1.1), lower backstop (27) has lower channel (28), lifting arm (6) extends through described lower channel, and lifting arm (6) can move together with stop element (25) between upper backstop (8) and lower backstop (27).

15. pipette according to claim 12, it is characterized in that, for the first mechanism (11 transmitted, 14) be the other mechanism for executive component (4) can not be connected with leading screw (8) with relatively rotating, described other mechanism allows executive component (4) to move axially with respect to leading screw (8).

16. pipette according to claim 13, it is characterized in that, described for making the other mechanism (11,14) that executive component (4) can not be connected with leading screw (8) with relatively rotating there is polyhedron, described polyhedron be embedded into executive component (4) complementation, in axially extended receptacle.

17. according to the described pipette of any one in claim 1 to 14, it is characterized in that one or more completely or partially being arranged on the soleplate (120) be fixed in housing (1.1) in following member:

Counter (23),

Counter transmission mechanism (21),

Atretic body (85),

Lever (92,93),

Other lever (106,108),

Spring element (89),

Other spring element (116,117).