EP1110612B1 - Pipetting system with pipette and syringe tip - Google Patents

Abstract

A pipette has clamping jaws (16) arranged on a piston holding device (13). The tip of the pipette can be inserted through the clamping jaws when the jaws are opened without or with only marginal contact of the piston head (8). The jaws can be laterally adjusted after the tip is placed on the piston head. Preferred Features: The adjusting movement of the jaws is tilted on the piston head in such a way that it has an essentially tangential component and the end position of the adjusting movement of the jaws on the piston head lies just before the dead point up to each side of the dead point.

Description

The invention relates to a pipette for a pipette system with a such a pipette and a syringe, namely a pipette with the features the preamble of claim 1.

There are pipettes in which each to be handled with the pipette Syringe axially inserted into the pipette or from this again is unmasked (DE 43 41 229 C1). In such a pipette, the fixing of cylinder takes place and piston of the syringe by radially deliverable Zylindergreifhebel and Plunger gripping levers. The cylinder grip levers and the piston grip levers stand under spring force in gripping position and are against spring force in the release position brought. Serve actuating elements on the pipette housing, the manually operated against the spring force.

Pipettes with axially insertable syringes are in terms of design the Zylindergreifeinrichtung and the piston gripping device constructive consuming. Structurally simpler are pipettes with radially into the Pipette retractable and removable from this syringe. From one such pipette, the present invention is based (DE 29 26 691 C2).

In the known pipette, from which the invention proceeds, the radially accessible, on the pipette housing fixedly mounted Zylindergreifeinrichtung as in plan view U-shaped flange-like edge with overlying pressure spring executed, the running as a circumferential, projecting flange Attachment section of the cylinder of the syringe after radial Pushes in. The piston head protruding upwards out of the cylinder the piston of the syringe is simultaneously with the insertion of the flange of the cylinder laterally into a piston receptacle on the piston gripping device introduced. The piston receptacle is of two lateral, common a U-forming jaws formed, which the piston head when inserting At the same time grasp the syringe sideways and hold it in a clamped position.

To the piston gripping device of the axially displaceable in the pipette housing Piston actuator in this pipette further includes an actuator, which is attached to the piston adjusting device. It is about here by a fold-out clamping member, which folded up to insert the syringe and for final fixing of the piston head between the Swinging jaws down. By swinging down they are already firmly attached to the piston head under their own spring force anyway Jaws additionally pressed against the piston head.

To the tight fit of an inserted piston head between the jaws to ensure is the starting point for the teaching of the invention each jaw with profilings, in particular with cutting-like Profiling provided. With appropriate material selection for the piston head are the profilings, especially when it comes to cutting-like profiles acts laterally in the material of the piston head pressed so that in terms of considerable axial forces, transferred in the operation of the piston adjusting device on the piston head be, not just a pure adhesion between jaws and Piston, but to some extent also gives a positive connection.

It has been shown in practice that the previously explained, from the state of Technique known construction in various respects capable of improvement is. On the one hand you have to the syringe when inserting into the pipette one exert considerable lateral force. The cylinder of the syringe can absorb this force without further ado. The problem is the piston and Piston head, especially for slimmer syringes. Especially the piston head namely, with great effort between the jaws of the piston gripping device be pressed. Sometimes you can only have that power Apply by pressing on the piston head itself. If you try that only by power transmission by means of the cylinder, so it can easily happen that the piston head breaks off or only crooked and thus inoperative sitting in the piston gripping device.

Furthermore, in this prior art when pressing the piston head between the laterally fitting jaws a non-positive Pre-fixing of the piston also in the axial direction. When inserted Syringe so you can possibly the insertion a bit too high seated piston head (not yet fully retracted piston) no longer move axially. You have to take out the syringe again and then Insert again with fully inserted piston.

The designed as a flap actuator for the piston gripping device must have a manual actuator to move it. This manual actuator interferes with during operation in the Hand held pipette, because it inevitably with the piston adjusting device moved together in the pipette housing axially. On the one hand, therefore, must a corresponding displacement in the pipette housing kept open On the other hand, the manual operation collides with the pipette holding Hand. This is especially in an ergonomically appropriate design the pipette housing problematic in which the pipette housing of the hand is completely covered.

The teaching is therefore based on the problem with a pipette for radial Inserting the syringe to overcome the difficulties outlined above.

The problem indicated above is solved with a pipette having the features of the preamble of claim 1 by the features of the characterizing one Part of claim 1.

According to the invention for operating the pipette laterally on the piston head of Syringe attaching jaws during insertion of the syringe ineffective or almost ineffective and will only after successful insertion the syringe to the piston head of the syringe hired. By this method can according to the invention the - sensitive - piston head Practically force-free in the piston seat insert. This eliminates the axial prefixing of the piston head so that, if necessary, the piston when he because something should project too far out of the cylinder, even when inserted Syringe can be pushed down. This can also be done automatically done, for example, by a chamfer on the open End of the pipette housing facing away from the closed end of the piston receiving the piston gripping device. The state of the art of which the Invention starts, although here has a correspondingly acting, axially working Clamping spring, which forms such an insertion bevel, the spring force But it must be very high, in spite of the clamping force of the already clamped employees Jaws an axial displacement of the piston in the inserted Reach position.

Finally, it is with appropriate design of a pipette according to the invention readily possible, on the flap as an actuator for the piston gripping device on the displaceable piston adjusting device to renounce. Rather, one can relatively easily have a fixed one Realize actuating device for the piston gripping device.

Of particular importance is an embodiment of the pipette according to the invention according to claim 2 to. The fact that the adjusting movement of the jaws is directed so that they with respect to the lateral surface of the piston head has a significant tangential component becomes the required Power for a sufficient positive connection of jaws and piston head as low as possible. When executing the jaws with cutting-like profiling, the production of the transfer takes place considerable axial tensile forces necessary positive connection not by realizable with only very high forces impressions of cutting-like profilings in the material of the piston head, but by cutting into the material with the tangential movement of the piston head. One must take into account that with conventional pipettes depending on the viscosity of the liquid to be pipetted quite forces up to 70 N or more can be transmitted in the axial direction have to. Of course, it must take every risk of slippage between the piston adjusting device and the piston head are avoided, to comply with the desired dosing accuracy. This comes along with it lowest possible forces generated positive connection through the cutting-like profiles on the jaws quite significant importance to.

Basically, with claim 5, the adjusting movement of the jaws produce by manual operation of the actuator. Even more convenient but it is, though the higher forces that are at the cutting of the cutting-like profilings in the material of the piston head apply are to produce by the actuator, the employment but to ensure itself by the spring force of Anstellfedern. The simplifies the construction of the actuator. In particular, allows this is a stationary arrangement of the actuator on the pipette housing. It is only for initial force application and later required for spreading the jaws. It must therefore only at full or largely in the cylinder retracted piston functional be. This can be the actuator of the movable Loosen the piston adjusting device and assign it to the pipette housing in a fixed position All advantages for the handling of the pipette according to the invention.

Preferred embodiments and further developments of the teaching of the invention are the subject of the dependent claims.

Fig. 1

in einer perspektivischen Ansicht ein Pipettensystem aus einer erfindungsgemäßen Pipette und einer daran angebrachten Spritze, funktionsbereit,

Fig. 2

das Pipettensystem aus Fig. 1 mit geöffneter Spritzenaufnahme,

Fig. 3

die Pipette des Pipettensystems aus Fig. 1 in einer Fig. 2 entsprechenden Darstellung,

Fig. 4

ausschnittweise, in stark vergrößerter Darstellung den Bereich der Spritzenaufnahme an der Pipette gemäß Fig. 3, das Gehäuse teilweise geöffnet,

Fig. 5

in vergrößerter Darstellung, ausschnittweise, eine Kolbengreifeinrichtung einer erfindungsgemäßen Pipette mit eingesetztem Kolbenkopf einer Spritze,

Fig. 6

eine Betätigungseinrichtung für die Kolbengreifeinrichtung aus Fig. 5, wobei die Klemmbacken der Kolbengreifeinrichtung wie in Fig. 5 an den Kolbenkopf angestellt sind,

Fig. 7

die Betätigungseinrichtung aus Fig. 6 mit gegen Federkraft gespreizten Klemmbacken der Kolbengreifeinrichtung.

In the following the invention will be explained with the explanation of a preferred embodiment with reference to the drawing. In the drawing shows

Fig. 1

in a perspective view of a pipette system of a pipette according to the invention and a syringe attached thereto, ready to work,

Fig. 2

the pipette system of FIG. 1 with opened syringe receptacle,

Fig. 3

2 shows the pipette of the pipette system from FIG. 1 in a representation corresponding to FIG. 2,

Fig. 4

Sectionally, in a greatly enlarged view of the area of the syringe holder on the pipette of FIG. 3, the housing partially open,

Fig. 5

in an enlarged view, fragmentary, a piston gripping device of a pipette according to the invention with inserted piston head of a syringe,

Fig. 6

an actuating device for the piston gripping device from FIG. 5, wherein the clamping jaws of the piston gripping device are set to the piston head as in FIG. 5,

Fig. 7

the actuator of FIG. 6 with splayed against spring force jaws of the piston gripping device.

1 shows a perspective view of a pipette system from a pipette 1 and a syringe 2. The pipette 1 is shown and preferred Embodiment to a motorized repeating pipette. However, the teaching of the invention is not on motor-driven repeating pipettes limited, it can be for any type of pipette with inserted syringe, be it manually operated or motorized.

In Fig. 1 can be seen on the pipette 1 handle moldings 3 and a Engine operation 4.

Fig. 4 in conjunction with Fig. 1 shows that in such a pipette 1 used syringe 2, which is commercially available as a replacement part is, as usual, a cylinder 5 with a mounting portion designed here as a flange 6 and having a piston 7. This is in Fig. 4 not visible, but hidden in the cylinder 5. Of him is only the same in the inserted state from the cylinder 5 end outstanding Recognize piston head 8.

The pipette 1 itself has a pipette housing 9, in which one in Fig. 4 only indicated recognizable piston actuator 10 arranged axially displaceable is. The piston adjusting device 10 is in a motorized pipette 1 moved by the motor, with a hand-operated pipette by hand, if necessary via a step mechanism, the z. B. works with pawl and rack.

Fixed to the pipette housing 9 is a radially accessible Zylindergreifeinrichtung 11. The Zylindergreifeinrichtung 11 is here as in the already above-mentioned prior art (DE 29 26 691 C2) simply as a U-shaped, flange-like edge on the pipette housing 9 executed on which the designed as a circumferential flange mounting portion 6 of the cylinder. 5 rests. This will be there on the edge by a pressure spring 12, the also indicated in Fig. 4, fixed non-positively.

Also provided is a radially accessible, on the piston adjusting device 10 with this displaceably mounted piston gripping device 13 for the Piston head 8 of a syringe 2 and an actuator 14 for this Piston gripping device 13. In this respect, reference may also be made in particular to FIG. 4 become.

In the following, further reference is made in particular to FIGS. 3, 4 and 5, to which the following explanations can be well understood. First, it is provided that the piston gripping device 13, the piston head 8 with inserted syringe 2 with in a piston seat 15 of the piston gripping device laterally applying jaws 16 engages and laterally clamping and axially considerable tensile forces from the piston adjusting device 10 holding the piston 7 transmits.

As far as explained above, the illustrated pipette corresponds 1 still by and large the technique, which from the state of the Technique already known. This also applies insofar as shown in the and preferred embodiment is provided that the jaws 16 of the piston gripping device 13 with profilings, here and after preferred teaching with cutting-like profiles 17 are provided. In Fig. 4 shows the blade-like profiles 17 on the jaws 16 of the piston gripping device 13. There are a total of six superposed cutting-like profiles 17 each jaw 16th

For teaching is now essential first that the jaws 16 with respect the piston seat 15 adjustable, in particular pivotable on the Piston gripping device 13 are arranged. The syringe 2 is open Jaws 16 without or with only marginal contact of the piston head 8 can be used by the jaws 16 and after insertion of the syringe 2 are then the jaws 16 on the piston head 8 laterally adjustable. This procedure in the pipette 1 according to the invention has the generally Part of the description explained benefits.

The illustrated and preferred embodiment is shown in Fig. 5 at Swivel axes 18 pivotally mounted jaws 16 with the thereto again preferably rotatably mounted blade-like profiles 17, executed here as cutting rollers.

The particularly well recognizable in Fig. 4 and 5, preferred embodiment also shows that the adjusting movement of the pivotable profiles 17 provided jaws 16 is directed so that they on the piston head 8 and the lateral surface of the piston head 8 a substantial tangential Component has. This is realized here by the fact that Swivel axes 18 for the jaws 16 laterally offset from the piston receiving 15 are located in the piston gripping device 13.

The recognizable in Fig. 5 embodiment further shows that according to the preferred Teach the end position of the adjusting movement of the jaws 16 the piston head 8 just before the dead center to just beyond the dead center lies. To call dead center is the point where the central axis the cutting-like profiling 17 of the jaw 16 exactly on the connecting line the central axis of the piston head 8 with the pivot axis 18th the jaw 16 is located. The embodiment shown in Fig. 5 shows an end position of the adjusting movement of the jaws 16, just this side the dead center lies. The aim is always a sufficiently long Cutting line of the cutting-like profilings 17 and nevertheless a safe Fixation of the piston head 8 between the jaws 16. Dazu you can u. U. also go to a position slightly beyond the dead center.

Even with the pipette 1 according to the invention can provide that the adjusting movement the jaws 16 by a manual operation of the actuator 14 is generated.

In the embodiment of a pipette 1 according to the invention is in particular Exploited dimensions that a good clamping action of the jaws 16 achieved with relatively little effort, at least maintained can be. Namely, in the illustrated embodiment provided that, although the higher force to cut the cutting-like Profilings 17 of the jaws 16 in the material of the piston head 8 is required, is generated by the actuator 14, but then that the employment of the jaws 16 by the force of Anstellfedern 19 is maintained. By the manual operation of the actuator In addition, 14 then only the opening of the jaws 16 causes against the spring force (see Fig. 5). Wins one additional degree of freedom for the arrangement of the actuator 14th

With clever design of the adjusting movement of the jaws 16 with cutting-like profiles 17 can even provide that only the Adjusting springs 19 generate the required contact force. At least, though They can, as in the illustrated embodiment, a sufficient contact force maintained to the required in operation considerable axial To transmit tensile forces.

Also in the pipette 1 according to the invention can, as in the state of Technique, the actuator 14 on the piston gripper 13th Arrange. This has explained in the general part of the description Disadvantage. The previously discussed concept with adjusting movement of the jaws 16 by spring force but it allows that, so in the embodiment realized, the actuator 14 for the piston gripping device 13 is attached to the pipette housing 9. It is therefore not with the piston adjusting device 10 displaced in the pipette housing 9, but as seen arranged in a fixed position in the pipette housing 9.

Positionally arranged in the pipette housing 9 means with respect to the actuating device 14 not necessarily that they are not movable at all is. In the illustrated and so far preferred embodiment shows namely, that the actuator 14 than the pipette 9 arranged closure for the piston seat 15 is executed. Exactly said in the illustrated embodiment, the actuator 14 designed as a closure slide. Of course, also versions would be Closure flap, rotary closure o. The like. Possible.

Fig. 1 shows the actuating device 14 forming closure slide down, pushed into the closed position, while Fig. 2, 3 and 4 the shutter, which forms the actuator 14, upwards pushed show. In this position, the actuator 14 is the Piston receptacle 15 free while in the position shown in Fig. 1 the piston receptacle 15 closes.

The illustrated and preferred embodiment shows in so far a Construction in which the actuator 14, the jaws 16 at closed piston seat 15 releases and with open piston receptacle 15 opens against the spring force. In the closed shown in Fig. 1 So you can position the piston head 8 by means of Piston actuator 10 safely coupled up and down move. In contrast, the position shown in Fig. 2, 3 and 4 is the Actuator 14 such, in which by means of the actuator 14, the jaws 16 of the piston gripping device 13 against the force of the pressure springs 12 are spread apart, so that the Piston head 8 is released. This corresponds to the release of the Piston receptacle 15 in this position, in the just then the syringe. 2 can be completely separated from the pipette 1.

5 is already with regard to the design of the piston gripping device 13 been addressed. With Fig. 5 are Fig. 6 and Fig. 7 in connection. Fig. 6 and Fig. 7 show that in the illustrated and insofar preferred embodiment, the actuator 14 inside a Wedge guide 20 for adjusting heads 21 of the jaws 16, wherein in illustrated embodiment, the wedge guide 20 at the bottom, open End is wide and converges towards the top. This can be in Fig. 6 and 7 recognize it very well. Fig. 5 shows the left of the two-armed levers, the form the jaws 16, the adjusting heads 21 of the jaws 16. This run in the wedge guides 20 on the inside of the illustrated embodiment the actuator 14 forming shutter slide. 6 shows the position of the adjusting heads 21 with respect to the wedge guide 20, which corresponds to the position of the jaws 16 in Fig. 5, so the position with fixed piston head 8. In contrast, Fig. 7 shows a position in which straight has been started, the shutter slide, the actuator 14 forms, in the position shown in Fig. 2, 3 and 4 upward slide. It can be seen that the adjusting heads 21 of the clamping jaws 16 already something have been spread apart, forced by the wedge guide 20. An the lower ends of the wedge guide 20 can be seen retaining grooves 22, in which the Engage adjusting heads 21 with the closing slide fully pushed upwards can. As a result, the open position of the actuating device 14 is fixed.

Of course, there are many other constructive possibilities, according to the invention Desired result possible jaws as little as possible adjustable 16th to reach. The illustrated embodiment therefore represents only a preferred constructive variant.

Fig. 4 of the drawing finally shows that even in the illustrated embodiment a pipette 1 according to the invention from the open end the pipette housing 9 facing away from the closed end of the piston receiving 15 an insertion bevel 23 is arranged for the piston head 8, by the piston head 8 when inserting the syringe 2 forcibly in the Position is brought, in which the piston 7 completely into the cylinder. 5 is inserted. The insertion bevel 23 for the piston head 8 can thereby be designed as an axially acting Durckfeder or such axial having acting compression spring.

Claims (10)

1. Pipette
   for a pipette system having a pipette (1) and syringe (2),
   in which a syringe (2) includes a cylinder (5) having a fastening section (6) preferably designed as a flange and a plunger (7) having a plunger head (8) extending beyond a basal end of the cylinder (5) when inserted in the pipette (1),
   having a pipette housing (9) and an axially moveable plunger-positioning device (10) in the pipette housing (9),
   having a radially accessible cylinder-gripping device (11) mounted on the pipette housing (9) for the fastening section (6) of a syringe (2),
   having a radially accessible plunger-gripping device (13) for the plunger head (8) of a syringe (2) mounted on the plunger-positioning device (10) and movable therewith, and
   an actuating device (14) for the plunger-gripping device (13),
   wherein, when the syringe (2) is inserted, the plunger-gripping device (13) grips the plunger head (8) with jaw chucks (16) mounted on the inner sides of a plunger receptacle (15) and clamps it in a manner clamping laterally and withstanding a substantial amount of axial traction force from the plunger-positioning device (10) on the plunger (7) and
   wherein, preferably, the jaw chucks (16) are provided with a profile, in particular a serrated profile (17),
   characterized in that the jaw chucks (16) are adjustable in respect to the plunger receptacle (15), in particular pivotably mounted on the plunger-gripping device (13),
   that, when the jaw chucks (16) are open, the syringe (2) is insertable through the jaw chucks (16) without or with only marginal contact of the plunger head (8) and
   that, after inserting the syringe (2), the jaw chucks (16) are laterally engagable on the plunger head (8).
2. Pipette according to claim 1, characterized in that the engaging movement of the jaw chucks (16) provided with serrated profiling (17) on the plunger head (8) is directed in a manner such that it has a substantially tangential component with respect to a contact surface of the plunger head (8) and, preferably, that the end position of the engaging movement of the jaw chucks (16) on the plunger head (8) lies approximately slightly before or slightly after dead center, wherein dead center is the point in which the centerline of the serrated profiling (17) of the jaw chucks (16) lies exactly on the connecting line of the centerline of the plunger head (8) with the rotating axis (18) of the jaw chucks (16).
3. Pipette according to claim 1 or 2, characterized in that the serrated profiling (17) is in the form of cutting rollers.
4. Pipette according to any one of claims 1 to 3, characterized in that the engaging movement of the jaw chucks (16) is produced by manually actuating the actuating device (14).
5. Pipette according to any one of claims 1 to 4, characterized in that the engaging movement of the jaw chucks (16) is produced - at least also - by the force of an engaging spring (19) or engaging springs (19) and that the opening of the jaw clamps (16) against elastic force is produced by manually actuating the actuating device (14).
6. Pipette according to any one of claims 1 to 5, characterized in that the actuating device (14) is mounted on the plunger-positioning device (10).
7. Pipette according to any one of claims 1 to 5, characterized in that the actuating device (14) is mounted on the pipette housing (9), and, preferably, that the actuating device (14) is designed as a closure for the plunger receptacle (15) mounted on the pipette housing (9), and, preferably, that the actuating device (14) is designed as a shutter.
8. Pipette according to claim 7, characterized in that, when the plunger receptacle (15) is closed, the actuating device (14) releases the jaw chucks (16) and, when the plunger receptacle (15) is open, the actuating device (14) opens the jaw chucks (16) against the force of the engaging spring (19) or engaging springs (19), and, preferably, that the actuating device has a guide piece (20) for the engager heads (21) of the jaw chucks (16), and, preferably, that the guide piece (20) is wider on a lower, open end and tapers upwardly.
9. Pipette according to claim 8, characterized in that the guide piece (20) has holding grooves (22) or the like for the engager heads (21) of the jaw chucks (16) on an end assigned to the open state of the jaw chucks (16), in which the engager heads (21) of the jaw chucks (16) are locked so that the actuating device (14) is fixed in the open position.
10. Pipette according to any one of claims 1 to 9, characterized in that an insertion bevel (23), being formed optionally as an axially operative compression spring or having an axially operative compression spring, is arranged on the closed end of the plunger receptacle (15) opposite the open end of the pipette housing (9).

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