EP1110612A2 - 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 the pipette to be handled in each case Syringe can be inserted axially into the pipette or can be removed from it (DE 43 41 229 C1). With such a pipette, the cylinder is fixed and piston of the syringe by means of radially adjustable cylinder gripping levers and Piston gripping lever. The cylinder gripping levers and the piston gripping levers are in place under spring force in the gripping position and are counter to spring force in the release position bringable. Actuators on the pipette housing serve this purpose can be operated by hand against the spring force.

Pipettes with axially insertable syringes are regarding the design the cylinder gripping device and the piston gripping device constructively complex. Pipettes with a radial design are simpler in design Syringe insertable and removable from this syringe. From one The present invention is based on such a pipette (DE 29 26 691 C2).

In the known pipette from which the invention is based, the radially accessible Cylinder gripping device fixed to the pipette housing as a top view U-shaped flange-like edge with pressure spring located above designed as a circumferential, projecting flange Attachment section of the cylinder of the syringe according to the radial Insert carries. The piston head protruding upwards from the cylinder the plunger of the syringe is simultaneously with the insertion of the flange of the cylinder laterally in a piston receptacle on the piston gripping device introduced. The piston holder is common to two lateral ones a U-forming jaws formed that the piston head when inserting Grasp the syringe sideways and hold it at the same time.

To the piston gripping device of the axially displaceable in the pipette housing The piston actuating device in this pipette also includes an actuating device, which is attached to the piston actuator. It is about here around a fold-out clamping member that flipped up to insert the syringe and to finally fix the piston head between the Jaws is pivoted down. By swinging down will already be firmly attached to the piston head under their own spring force Clamping jaws additionally pressed against the piston head.

To ensure that an inserted piston head is firmly seated between the clamping jaws Ensuring is the starting point for the teaching of the invention each jaw with profiling, in particular with cutting-like Provide profiles. With appropriate material selection for the piston head will be the profiles, especially if it is cutting-like profiles act laterally in the material of the piston head indented so that with regard to the considerable axial forces, which are transferred from the piston actuator to the piston head during operation become, not just a pure frictional connection between jaws and Piston head, but to a certain extent also gives a positive fit.

It has been shown in practice that the previously explained, from the prior art Technique known construction can be improved in various respects is. First, you have to put a syringe on the syringe when inserting it into the pipette exert significant lateral force. The barrel of the syringe can easily absorb this force. This is problematic with the piston and Piston head, especially for slimmer syringes. Especially the piston head must namely with great effort between the jaws of the piston gripping device be pressed. You can only do this sometimes apply by pressing on the piston head itself. If you try that just by power transmission through the cylinder so it can easily happen that the piston head breaks off or only crooked and therefore inoperable sits in the piston gripping device.

Furthermore, in this prior art, the piston head is pressed in a non-positive between the side jaws Pre-fixation of the piston also in the axial direction. When inserted The syringe can therefore be a little too high when inserted sitting piston head (piston not yet fully retracted) no longer move axially. You have to take the syringe out and then reinsert with piston fully inserted.

The actuating device designed as a closure flap for the piston gripping device must have a manual override to move them. This manual control element interferes with operation in the Hand-held pipette because it is imperative to use the piston actuator axially moves together in the pipette housing. On the one hand, therefore a corresponding displacement path in the pipette housing is kept open manual operation collides with the one holding the pipette Hand. This is particularly the case with an ergonomically appropriate design problem of the pipette housing, in which the pipette housing by the hand is completely gripped.

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

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

According to the invention for the operation of the pipette on the side of the piston head Syringe clamping jaws ineffective while inserting the syringe or almost ineffective and only become effective after insertion the syringe against the plunger head of the syringe. Through this method can - according to the invention - the - more sensitive - piston head insert into the piston holder practically without force. This also eliminates the axial pre-fixation of the piston head, so that, if necessary, the piston when it because it should protrude a little too far from the cylinder, even when it is inserted Syringe can be pushed down. This can also be done automatically happen, for example by an insertion slope on the open Closed end of the piston receptacle facing away from the end of the pipette housing the piston gripping device. The state of the art of which Invention is based here has a correspondingly acting, axially working Clamping spring, which forms such an insertion slope, the spring force but must be very high in order to despite the clamping force of those already employed Jaws an axial displacement of the piston into the inserted To reach position.

Finally, it is with a corresponding design of a pipette according to the invention easily possible on the shutter as an actuator for the piston gripping device on the sliding piston adjusting device to renounce. Rather, one can relatively easily find a fixed one Implement actuating device for the piston gripping device.

An embodiment of the pipette according to the invention is of particular importance according to claim 2. The fact that the adjusting movement of the jaws is steered so that it is with respect to the outer surface of the piston head has an essential tangential component, the required Strength for a sufficient positive connection of clamping jaws and piston head as low as possible. When executing the jaws with cutting-like profiles the manufacture for the transfer takes place considerable axial tensile forces necessary positive connection not by impressing the cutting-like profiles in the material of the piston head, but by cutting into the material with the tangential movement the piston head. You have to take into account that with conventional pipettes depending on the viscosity of the liquid to be pipetted forces up to 70 N or more can be transmitted in the axial direction have to. Of course, there must be any risk of slip between the piston adjusting device and the piston head are avoided, to maintain the desired dosing accuracy. This comes with lowest possible forces generated positive connection through the cutting-like profiles on the jaws are of considerable importance to.

In principle, claim 5, the positioning movement of the jaws by manually operating the actuator. Even more convenient it is, however, the higher forces that are necessary to cut the to apply cutting-like profiles in the material of the piston head are to generate the employment by the actuator but to ensure itself by the spring force of adjusting springs. The simplifies the construction of the actuator. In particular enables this is a fixed arrangement of the actuating device on the pipette housing. It is only for the initial application of force and later required to spread the jaws. It therefore only needs to be full or largely operational in the piston retracted piston his. So that you can move the actuator from the Loosen the piston setting 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 refinements and developments of the teaching of the invention are the subject of the subclaims.

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 is further explained with the explanation of a preferred embodiment with reference to the drawing. In the drawing shows

Fig. 1

a perspective view of a pipette system consisting of a pipette according to the invention and a syringe attached to it, ready for operation,

Fig. 2

1 with the syringe holder open,

Fig. 3

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

Fig. 4

detail, in a greatly enlarged representation, the area of the syringe holder on the pipette according to FIG. 3, the housing partially opened,

Fig. 5

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

Fig. 6

5, the clamping jaws of the piston gripping device being set against the piston head as in FIG. 5,

Fig. 7

6 with the jaws of the piston gripping device spread against spring force.

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

In Fig. 1 one recognizes handle shapes 3 and one from the pipette Motor control 4.

Fig. 4 in connection with Fig. 1 reveals that with such a pipette 1 used syringe 2, which is commercially available as a replacement part is, as usual, a cylinder 5 with a fastening section designed here as a flange 6 and with a piston 7. This is in Fig. 4 not recognizable, but hidden in cylinder 5. Only him is from him in the inserted state protruding from the end of the cylinder 5 Recognize piston head 8.

The pipette 1 itself has a pipette housing 9, in which only one in FIG. 4 indicated indicated piston actuator 10 axially displaceable is. The piston actuating device 10 is used in a motor-operated pipette 1 moved by the motor, with a manually operated pipette by hand, if necessary via a step mechanism that z. B. works with jack and rack.

A radially accessible cylinder gripping device is fixedly attached to the pipette housing 9 11. The cylinder gripping device 11 is here as in the already State of the art mentioned above (DE 29 26 691 C2) simply as a U-shaped, flange-like edge on the pipette housing 9, on which the Fastening section 6 of the cylinder 5 designed as a circumferential flange lies on. This is there on the edge by a pressure spring 12, the is also indicated in Fig. 4, non-positively fixed.

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

In the following, reference is made in particular to FIGS. 3, 4 and 5 which the following explanations can be easily understood. First, it is provided that the piston gripping device 13 the piston head 8 when syringe 2 is inserted with in a piston holder 15 of the piston gripping device lateral clamping jaws 16 grips and laterally clamping and axially considerable tensile forces from the piston actuating device 10 holds the piston 7 transmitting.

To the extent that this has been explained above, the pipette shown corresponds 1 still broadly based on the state of the art Technology is already known. This also applies to the extent shown in the and preferred embodiment is provided that the jaws 16 of the piston gripping device 13 with profiles, here and after preferred teaching are provided with cutting-like profiles 17. In Fig. 4 shows the cutting-like profiles 17 on the jaws 16 of the piston gripping device 13. There are a total of six stacked cutting-like profiles 17 per jaw 16.

For the teaching it is now essential that the jaws 16 with respect the piston holder 15 adjustable, in particular pivotable on the Piston gripping device 13 are arranged. The syringe 2 is open Clamping jaws 16 without or only marginally touching the piston head 8 insertable through the jaws 16 and after inserting the syringe 2, the clamping jaws 16 can then be adjusted laterally on the piston head 8. This procedure for the pipette 1 according to the invention is generally the same Advantages explained in part of the description.

The illustrated and preferred embodiment shows in FIG Swivel axes 18 pivotally mounted jaws 16 with the again preferably rotatably mounted cutting-like profiles 17, executed here as cutting rollers.

The particularly preferred embodiment shown in FIGS. 4 and 5 also shows that the adjustment movement of the pivoting profiles 17 provided jaws 16 is steered so that it on the piston head 8 or the outer surface of the piston head 8 a substantial tangential Component. This is realized here in that the Swivel axes 18 for the jaws 16 laterally offset for the piston holder 15 are in the piston gripping device 13.

The embodiment shown in Fig. 5 further shows that more preferred Teach the end position of the positioning movement of the jaws 16 the piston head 8 just before the dead center to just beyond the dead center lies. The dead center is the point at which the central axis the cutting-like profile 17 of the jaw 16 exactly on the connecting line the central axis of the piston head 8 with the swivel axis 18 the jaw 16 is. The embodiment shown in Fig. 5 shows an end position of the positioning movement of the jaws 16, which is just on this side the dead center. The aim is always a sufficiently long one Cutting line of the cutting-like profiles 17 and nevertheless a safe one Fixing the piston head 8 between the jaws 16. For this purpose can u. U. also go to a position slightly beyond the dead center.

With the pipette 1 according to the invention it can also be provided that the positioning movement the jaws 16 by manual actuation of the actuator 14 is generated.

In the exemplary embodiment of a pipette 1 according to the invention, in particular Dimensions exploited that a good clamping effect of the jaws 16 achieved with comparatively little effort, at least maintained can be. In the illustrated embodiment is namely provided that although the higher force required to cut the blade-like Profiling 17 of the jaws 16 in the material of the piston head 8 is required, is generated by the actuating device 14, but that then the adjustment of the jaws 16 by the force of adjusting springs 19 is maintained. By manual actuation of the actuation device 14 is then only the opening of the jaws 16 causes against the spring force (see Fig. 5). So wins an additional degree of freedom for the arrangement of the actuator 14.

With skillful design of the positioning movement of the jaws 16 with cutting-like profiles 17 can even provide that only the Adjusting springs 19 generate the required adjusting force. At least you can, as in the illustrated embodiment, a sufficient pitch maintained to the substantial axial required in operation To be able to transmit tensile forces.

The pipette 1 according to the invention can also be used, as in the prior art Technology, the actuating device 14 on the piston gripping device 13 arrange. This has been explained in the general part of the description Disadvantage. The previously explained concept with the adjusting movement of the clamping jaws 16 by spring force, however, allows that, also 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 displaceable in the pipette housing 9, but seen in this way arranged in a stationary manner in the pipette housing 9.

Arranged stationary in the pipette housing 9 means with regard to the actuating device 14 not mandatory that this is not movable at all is. In the illustrated and so far preferred embodiment shows namely, that the actuating device 14 as on the pipette housing 9th arranged closure for the piston receptacle 15 is executed. I agree said in the illustrated embodiment, the actuator 14 executed as a slide valve. Of course, versions would also be as Locking flap, twist lock or the like possible.

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

The illustrated and preferred embodiment shows one Construction in which the actuator 14, the jaws 16 at closed piston receptacle 15 releases and with the piston receptacle open 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 securely coupled up and down move. In contrast, the position shown in FIGS. 2, 3 and 4 is the Actuating device 14 one in which by means of the actuating device 14 oppose the jaws 16 of the piston gripping device 13 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 holder 15 in this position, in which the syringe 2 can be separated from the pipette 1 in total.

5 is already regarding the design of the piston gripping device 13 been addressed. 5, FIGS. 6 and 7 are related. Fig. 6 and Fig. 7 show that in the illustrated and so far 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 It is wide at the end and converges towards the top. This can be seen in Fig. 6 and 7 recognize very well. Fig. 5 shows on the left on the two-armed levers form the jaws 16, the actuating heads 21 of the jaws 16. These run in the wedge guides 20 on the inside of the embodiment shown the actuator 14 forming shutter. 6 shows the position of the adjusting heads 21 with respect to the wedge guide 20, which corresponds to the position of the clamping jaws 16 in FIG. 5, that is to say the position with fixed piston head 8. In contrast, Fig. 7 shows a position in which straight has begun, the slide valve, the actuator 14 forms in the position shown in FIGS. 2, 3 and 4 upwards push. It can be seen that the adjusting heads 21 of the jaws 16 are somewhat have been spread apart, forced by the wedge guide 20. An the lower ends of the wedge guide 20 can be seen holding grooves 22 into which the Engage the adjusting heads 21 with the slide slide fully pushed up can. The open position of the actuating device 14 is thereby fixed.

Of course there are many other constructive possibilities that the invention Desired result adjustable clamping jaws 16 with as little force as possible to reach. The illustrated embodiment is therefore only a preferred one constructive variant.

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

Claims (10)

pipette for a pipette system with pipette (1) and syringe (2), A syringe (2) has a cylinder (5) with a fastening section (6), which is preferably designed as a flange, and a piston (7) with a piston head (8) protruding from the end of the cylinder (5) when inserted into the pipette (1). having, with a pipette housing (9) and a piston actuating device (10) which can be displaced axially in the pipette housing (9), with a radially accessible cylinder gripping device (11) attached to the pipette housing (9) for the fastening section (6) of a syringe (2), with a radially accessible piston gripping device (13) for the piston head (8) of a syringe (2) and with an actuating device (14) for the piston gripping device (13), The piston gripping device (13) grips the piston head (8) when the syringe (2) is inserted with clamping jaws (16) attached laterally in a piston receptacle (15) and laterally clamping and axially considerable tensile forces from the piston adjusting device (10) on the piston (7) transmits and wherein, preferably, the clamping jaws (16) are provided with profiles, in particular with cutting-like profiles (17), characterized, that the clamping jaws (16) are adjustable, in particular pivotably, on the piston gripping device (13) with respect to the piston receptacle, that the syringe (2) can be used with the jaws (16) open or with only marginal contact with the piston head (8) by the jaws (16) and that the clamping jaws (16) can be adjusted laterally after inserting the syringe (2) on the piston head (8). Pipette according to claim 1, characterized in that the positioning movement the jaws provided with cutting-like profiles (17) (16) on the piston head (8) is steered so that it with respect to the lateral surface of the Piston head (8) has an essential tangential component, and preferably, that the end position of the positioning movement of the clamping jaws (16) to the piston head (8) just before the dead center to just beyond the dead center lies. Pipette according to claim 1 or 2, characterized in that the cutting-like Profilings (17) are designed as cutting rollers. Pipette according to one of claims 1 to 3, characterized in that the adjusting movement of the clamping jaws (16) by manual actuation of the actuating device (14) is generated. Pipette according to one of claims 1 to 4, characterized in that the adjusting movement of the jaws (16) - at least - by Force is generated by a positioning spring (19) or positioning springs (19) and that by manual operation of the actuator (14) the opening of the Clamping jaws (16) is generated against the spring force. Pipette according to one of claims 1 to 5, characterized in that the actuating device (14) is attached to the piston actuating device (10) is. Pipette according to one of claims 1 to 5, characterized in that the actuating device (14) is attached to the pipette housing (9), and, preferably that the actuating device (14) as on the pipette housing (9) attached closure for the piston receptacle (15) is executed, and preferably that the actuator (14) as a slide gate is executed. Pipette according to claim 7, characterized in that the actuating device (14) the jaws (16) with the piston holder closed (15) releases and with open piston holder (15) against the force of Adjusting spring (19) or adjusting springs (19) opens, and, preferably, that the Actuating device (14) inside a wedge guide (20) for adjusting heads (21) the jaws (16), and, preferably, that the wedge guide (20) stands wide at the lower, open end and converges towards the top. Pipette according to claim 8, characterized in that the wedge guide (20) on the associated with the spread state of the jaws (16) End of the holding grooves (22) or the like for the adjusting heads (21) of the clamping jaws (16) into which the adjusting heads (21) of the clamping jaws (16) snap, so that the actuating device (14) is fixed in the open position. Pipette according to one of claims 1 to 9, characterized in that at the closed end facing away from the open end of the pipette housing (9) End of the piston receptacle (15), possibly designed as an axially acting compression spring or an insertion bevel having an axially acting compression spring (23) for the piston head (8) is arranged.

Images