System for withdrawing blood

(12) PATENT DESCRIPTION (19) PL (11) 196255 (13) B1 (21) Application number: 360436 ^{(13) B1}(22) Date of notification: October 30, 2001 ^{(51) Int.Cl.}

A61B 5/15 (2006.01) (86) Date and number of the international application:

2001-10-30, PCT / EP01 / 12527 (87) International application publication date and number:

2002-05-10, WO02 / 36010 PCT Gazette No. 19/02

<td colspan="2">₍₅₄₎ System for withdrawing body fluids, a method for temporarily ejecting a needle⁽⁵⁴⁾ from the device for withdrawing bodily fluids and a lancing unit</td>

<td></td><td>(73) The right holder of the patent: F.HOFFMANN-LA ROCHE AG, Basel, CH</td>

<td>(30) Priority:</td><td></td>

<td>2000-10-31, DE, 10053974.2</td><td>(72) Inventor (s):</td>

<td>(43) Application was announced:</td><td>Michael Fritz, Biblis, DE Klaus-Dieter Sacherer, Kirchheim, DE Hans List, Hesseneck-Kailbach, DE</td>

<td>September 6, 2004 BUP 18/04</td><td>Thomas Weiss, Mannheim, DE</td>

<td>(45) The grant of the patent was announced: 31.12.2007 WUP 12/07</td><td>Frank Deck, Niederkirchen, DE Claudio Immekus, Mannheim, DE (74) Representative: Szczepańska Zofia, PATPOL Sp. z o. o</td>

(57) 1. System for withdrawing body fluids, characterized in that it comprises a drive unit (100, 100 ') with a pusher (10, 110) that moves to perform the lancing operation from a rest position to the lancing position, and a lancing unit (20, 120, 120 '), in which there is a lancet (30, 130, 130') with a needle, which in the resting position of the pusher is inside the lancing unit, and moves through the pusher when moving to the lancing position so that that the needle exits at least partially through the exit orifice (41, 41 ') of the lancing unit, the plunger and the lancet engaging a form fit for the puncture operation, and the plunger has an attachment area (11) that can be held by the fastening device ( 32a, 32b) on a form-fit lancet, or the lancet has a mounting area (131) which is retained by a fastening device (132a, 132b) on the plunger, the fastening device is initially in the open position when the lancet and the plunger are not engaged and, due to the longitudinal movement, surrounds to close the mounting region, the at least one fastening element of the fastening device moving transversely in the longitudinal direction in the closed position when the lancet and the plunger are coupled such that the lancet is connected to the follower by a form fit.

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PL 196 255 B1

Description of the invention

The present invention relates to a system for withdrawing body fluids, a method for temporarily removing a needle from a body fluid withdrawal device, and a lancing unit. This system serves to withdraw body fluids from parts of the body, in particular the fingertip, by making a small puncture.

In the field of clinical diagnostics, it is necessary to obtain samples of body fluids, in particular blood samples, in order to determine their content of constituent substances. If more blood is needed, it is usually drawn with a syringe or similar device that is inserted into the blood vessels. However, the present invention relates to an area where small amounts of sample, in the range of a few µΐ or less, are needed to determine the analytical parameters. This procedure is widely used, in particular for measuring blood sugar levels, but is also applicable to the determination of coagulation parameters, triglycerides, HBA1c or lactate. In the field of diabetes mellitus, people with diabetes control their own sugar levels (so-called home monitoring). This is needed to bring the blood sugar level back to normal by administering insulin. If the camera shows that you are low on blood (hypoglycaemia), it may lead to unconsciousness or even death. If, on the contrary, the patient has too much sugar, it has grave consequences such as blindness and gangrene.

Small hand-held blood collection machines, so-called lancing aids, required for measuring blood sugar levels, which can be easily and reliably operated by the user, nurse and support staff, have become widespread. Recently, systems for the collection of interstitial fluids have also been known, with which, in principle, appropriate analyzes can be performed.

A significant problem in this field is contamination and injury from the lancets used. With many commercially available apparatuses, the lancet is either removed or discarded after the puncture operation. The free, in this case, needle of the lancet can lead to injuries which can lead to infections. Therefore, some countries seek to prohibit blood collection systems in which the point of the needle becomes freely accessible after use.

Prior art documents describe various variants of blood withdrawal systems in which the needle is protected after the puncture operation. US 5 314 442 describes a lid in which a lancet is placed. To perform the puncture operation, the lancet is advanced out of the sheath by a pusher or the like so that the needle extends out through the opening. Following puncture, the lancet is retracted into the sheath and the flexible elements on the lancet ensure that the lancet needle cannot escape without the pusher action. Similar systems based on this principle have been described in US 4,990,154 and 5,074,872 and in WO 00/02482. A further system in which the retraction of the lancet into the sheath is achieved by an integrated spring is described in DE 198 55 465. While the mentioned documents already deal with the problem of contamination or injury to the user, the coupling of the drive mechanism to the lancet is only achieved by thorough compression. In this case, the puncture depth of the needle is limited by the stopper. It has turned out, however, that the impact of the lancet against the bumper leads to a vibration of the needle which increases the pain on puncture. This problem is described in more detail in the patent description EP 0565 970.

The object of the present invention is to propose a system for withdrawing physiological fluids which, on the one hand, avoids contamination or infection from the lancets used, and, on the other hand, allows the user to perform a little painful puncture. A further object is to simplify the systems known from the state of the art, reduce the costs of their production and, in particular, to propose a solution by which the systems can be made smaller. The latter point is particularly important when developing an arrangement that works with stored lancets and allows the user to change to an unused lancet without having to undertake complicated handling steps for this purpose.

The system for withdrawing bodily fluids according to the invention is characterized in that it comprises a drive unit with a pusher that moves to carry out the lancing operation from a rest position to the lancing position, and a lancing unit in which a needle lancet is located, which in a resting position the pusher is inside the lancing unit and moves through the pusher when it moves to the piercing position so that that the needle exits at least partially through the exit orifice of the lancing unit, the plunger and the lancet are engaged by a form fit for the puncture operation and the pusher has an attachment region which can be held on the lancet in the form of a form fit by means of the fastening device. , or the lancet has an attachment area which is retained by a clamping device on the plunger, the fastening device is initially in the open position when the lancet and the plunger are not engaged and, due to the longitudinal movement, surrounds to close the mounting region, the at least one fastening element of the fastening device moving transversely in the longitudinal direction in the closed position when the lancet and the plunger are coupled such that the lancet is connected to the follower by a form fit.

Preferably, the lancing unit includes a sleeve in which the lancet is slidably disposed.

Preferably, the lancet clamping device or plunger has at least one movable element which moves perpendicular to the lancet position inside the sleeve towards the puncture position so that the plunger is connected to the lancet by a form fit.

Preferably, the sleeve has a channel through which the lancet moves, the channel having a narrowing whereby at least one element moves in a direction perpendicular to that direction during the movement of the lancet towards the puncture position.

Preferably, the lancing unit is removably mounted on the drive unit.

Advantageously, the coupling of the pusher with the lancet in the form of a form fit is achieved by applying the cover to the drive unit.

Preferably, when disengaging the lancing unit from the drive unit, the coupling of the plunger and the lancet is disengaged.

Preferably, the fastening device comprises at least two flexible elements which move towards each other when the plunger is engaged with the lancet.

Preferably, the system includes a device for adjusting the amount of needle protruding from the cover.

Preferably, the system has a magazine with a plurality of lancets which can be sequentially engaged with a follower of the drive unit.

Preferably, the fastening device has two or more fastening elements which close when you place the lancing unit on the drive unit, such that the fastening elements hold the lancet mounting area.

Preferably, the fasteners are associated with a spring element that moves the fasteners towards each other.

Advantageously, the fastening elements can be biased by the tensioning element against the force of the spring element so that they are open, and applying the lancing unit to the drive unit releases the tensioning element so that the fastening elements move relative to each other.

The method of temporarily removing a needle from a device for withdrawing bodily fluid from the body according to the invention is characterized in that it comprises the steps of

- coupling the lancet to the pusher of the drive unit by means of a form fit, where either the pusher has a clamping area and the lancet has a clamping device, or the lancet has a clamping region and the pusher is equipped with a clamping device,

- moving the plunger from a rest position in which the lancet needle is in the lancing unit to a position where the needle extends from the exit opening of the lancing unit, the clamping device being initially in the open position when the lancet and plunger are not engaged and by movement longitudinal clamping device, at least one clamping element of the clamping device moves transversely to the longitudinal direction so that the at least one securing element at least partially surrounds the securing area such that the securing device is in the closed position when the lancet and the plunger are engaged such that the lancet is connected to the pusher by a form fit,

- the return movement of the pusher to retract the needle back into the lancing unit.

Preferably, the coupling of the lancet to the drive unit is achieved by applying the lancing unit to the drive unit.

Preferably, engagement of the lancet with the pusher is released by removing the lancing unit from the drive unit.

The lancing unit for application to the drive unit according to the invention is characterized in that it comprises a lancet with a needle and a fastening device with fastening means for producing a form-fit connection with the pusher of the drive unit, wherein

The fastening device is initially in the open position when the lancet and the plunger are not engaged and the fastening members move transversely in the longitudinal direction as they move along the lancet in the sleeve of the lancing unit in the closed position when the lancet and the plunger are engaged such that the lancet is connected to the pusher by means of a form fit.

Preferably, the sleeve has a taper whereby the securing elements move relative to each other as the lancet passes through the sleeve.

The system for withdrawing bodily fluids according to the invention is also characterized in that it comprises a drive unit with a pusher that moves to carry out the lancing operation from a rest position to the lancing position, and a lancing unit in which a lancet is provided with a needle which the rest position of the pusher is inside the lancing unit and the pusher, when moving to the puncture position, moves in such a way that that the needle exits at least partially through the exit opening of the lancing unit, the plunger and the lancet being engaged by a form fit for the lancing operation in the longitudinal direction, the fastening device which is initially in the open position when the lancet and plunger are not engaged, engages the clamping area in the closed position by movement of at least one securing element transversely to the longitudinal direction, when the lancet and the plunger are coupled such that the lancet is connected to the plunger by a form fit.

An essential feature of the system is that the plunger and the lancet are engaged with each other by a form fit to carry out the puncture.

The form of a form fit within the meaning of the present invention is characterized in that it enables the lancet and the drive plunger to be coupled together with little effort. There are two main variants of obtaining a form fit. In a first variant, in order to engage the lancet and the plunger of the drive, the mold is closed such that the retention element is wrapped around. In the context of the present invention, the banding block is designated as a fastening device. If the fastening device is on the lancet, the pusher of the drive exhibits the fastening element, if, on the contrary, the fastening device is on the pusher of the drive, the fastening element is placed on the lancet (Figures 1 and 2 show practical embodiments). These form-fit variants are advantageously achieved in that a transverse movement of the fastening elements of the (first open) fastening device is obtained by a longitudinal movement in the puncture direction, which here closes in the fastening area. Preferably, when closing the fastening device, the fastening element is (at least partially) grasped such that the lancet is pulled as well when the plunger of the drive is withdrawn - at least until the fastening device is opened. Moreover, it is advantageous for the clamping device and the clamping area to be geometrically matched with each other so that, after the form fitting is obtained, no or only very little tolerance is formed in the puncture direction and the movement of the drive plunger both in the puncture direction and in the opposite direction flows freely to the movement of the lancet. This can be achieved when the longitudinal extension of the chamber with the clamping device closed is in line with the longitudinal extension of the clamping area or only slightly greater (see Fig. 1). In another embodiment of this variant, the recesses in the fastening area and the fastening elements of the fastening device are so aligned with each other in terms of elongation that a completely free transport in the direction of the lancing is possible (see Fig. 2).

In a second variant of the form fit, both the fastening device and the fastening area are substantially permanent, and the surrounding of the fastening area by the fastening device is achieved by the mutual movement of the forms provided by the two. As these units are permanent in form, it is not possible to fully embrace, but the fittings must be open enough to move relative to each other. The movement with respect to one another is thereby achieved (at least over a distance of the travel path) transverse to the puncture direction and a coupling is produced which is equally free in the puncture direction (see FIG. 4). Finally, a coupling by movement is also possible, which has components both transversely and parallel to the direction of the puncture (see Fig. 7).

The blood collection system according to the invention has a drive unit with a pusher, by which the lancet moves from the rest position to the puncture position. A number of drive mechanisms are known in the art that can be used in the field of blood collection apparatus. In particular, drive mechanisms are widely used which draw their energy from a previously tensioned spring. In the context of the present invention, drive units are preferably used which enable the directed movement of the plunger and the lancet, which is conditioned by the form-fit engagement. A guided movement is considered to be when both the lancet is punctured to a certain depth in the body and is pulled out after a certain time and along a certain path.

PL 196 255 B1 from the body. With the usual prior art systems based on a combination of spring and impact, the path-time course is influenced by many parameters, such as manufacturing tolerances (system friction, spring force) as well as the skin surface. The guided movement of the lancet, as described, for example, in EP 565 970 by a guide yoke, has turned out to be advantageous in terms of pain on puncture. With regard to the drive unit, the preferred drive mechanisms known from EP 565 970 and US 4 924 879 come into consideration.

An important embodiment of the invention provides a lancing unit which is detachable from the drive unit and which houses at least one lancet. The lancing unit comprises a housing in which a lancet is placed in a rest position. In this way, injuries caused by the lancet before or after use or contamination can be avoided. The housing may be configured to receive a single lancet or may be in the form of a multi-lancet magazine. As a rule, the lancets are located inside the magazine in separate chambers in order to prevent contamination of unused lancets with those already in use. The housing of the lancing unit is shaped such that it can be attached to the drive unit. For this purpose, the lancing unit can be designed, for example, in the form of a cover which is placed on the drive unit. Such embodiments have been described, for example, in the following patents: US 5,314,442, US 4,990,154 and US 5,074,872. An embodiment is also possible in which the lancing unit is permanently associated with the drive unit or is an integral part of the drive unit. This can be advantageous, in particular, for systems with a magazine, where the entire unit is thrown away when the magazine is used up. In the case of a magazine-type lancet unit, it may have, for example, adjacent chambers in which the lancets are provided, and the chambers are sequentially placed in the drive unit so that the lancets can be coupled to a follower of the drive unit. A drum-type magazine with lancets housing chambers arranged parallel to the longitudinal axis of the drum is also particularly advantageous. Similar to a revolver cylinder, such a magazine can be repeatedly loaded into the drive unit.

A further requirement for the lancing unit is the sterility of the lancets, which must be ensured over a long period of time. The sterility of the lancing unit can be achieved, as is customary in the art, by irradiation with gamma radiation. In order to maintain the sterile conditions properly, the lancing unit can be sealed in a sealed package, for example a polyethylene bag. In another embodiment, the openings of the lancing unit (for insertion of the pusher and for the exit of the needle tip) can be closed with a sealed foil. This may, for example, be a peel-off foil that is removed by the user prior to use. Preferably, however, thin films can be used which are pierced by the plunger or the needle tip during use, so that the user is spared additional handling. Such films can already be produced integrally in the manufacturing process of the lancing unit, which is usually an injection molding process.

In a further preferred embodiment, the needle tip is protected against contamination by an elastomer which is pulled off prior to puncture or is punctured during puncture in order to release the needle tip. Such protection of the needle against contamination is described in WO 01/66010, which is incorporated herein by reference.

There are one or more needle lancets inside the lancing unit. Regardless of the possible devices on the lancet which allow for positive engagement with the plunger, lancets as are sufficiently known in the art can be used in the context of the present invention. As a rule, such lancets have a plastic base body in which a metal needle is inserted. However, lancets without a separate base body are also possible (for example metal needles with a loss at the rear end as the attachment area).

It is important to the present invention that the plunger of the drive unit and the puncture lancet are engaged with each other by a form fit. This is where the invention differs significantly from the state of the art, where the mechanical coupling between the lancet and the drive is accomplished by fine pressing (US 5,314,442, US 4,990,154, US 5,074,872), a catch lever (WO 00/02482), a clamped connection (US Patent 3 030 959) or simply by pressure (DE 198 55 465). The form of a form fit is distinguished in that a mechanically reliable coupling between the drive and the lancet is achieved in this case without a great pressure force on the lancet in the direction of the puncture movement. In the case of prior art devices that work with a press-fit joint in the lid,

A spring element (e.g. in DE 198 55 465) or a stop element (e.g. in WO 00/02482) must be provided that holds the lancet so that the lancet, when engaging the lancing unit with drive unit did not come out of the lid. The spring elements in the lancing unit, however, lead to an increase in the production costs, which is particularly important since the lancing unit is a consumable material. In contrast, the overcoming of the retention element requires additional force on the side of the drive unit, and the overcoming also leads to needle vibration, which increases puncture pain. Moreover, in the case of systems that work with a press fit, the guided movement that causes the lancet to be withdrawn is problematic, as in this case the press fit can thereby be disengaged. Although the ratchet connection described in WO 00/02482 solves this problem, it is technically difficult to produce. In particular, it is difficult to establish such a ratchet connection in a continuous manufacturing process, since even slight variations in material or process conditions render the device inoperable. A further disadvantage of the device described in WO 00/02482 is that a ratchet joint is formed in the region of the path that serves to make a body puncture. Force deviations and vibrations that occur in the ratchet connection adversely affect the pain during puncture. A further disadvantage of this device is that the needle remains in the body after puncture and is not actively withdrawn. The needle is only pulled out when the cover is removed from the drive mechanism. In the case of a form fit from the plunger of the drive and the lancet according to the present invention, the connection between the plunger and the lancet can, on the contrary, be achieved without the need to apply any particular force in the puncture direction, and furthermore, a positive fit can be used to actively withdraw the needle after puncture. Due to this possibility of actively controlling the needle path-time curve by the drive unit, it is possible to set the puncture sequence as painless as possible.

Fig. 8 shows diagrammatically the force (f) - path (s) of the coupling process of the drive and the lancet for the press fit joint (a), the ratchet connection (b) and the form fit (c). It can be seen that when a press fit is used, the force increases strongly until the lancet is released from position when it is held by a retaining member or a spring. In a ratchet connection, the force increases with the binding and decreases as the connection is made. In the form of a positive fit, only slight forces are required for the fastening elements to slide together.

Further properties of the form joints according to the invention will become clear when compared with the solution disclosed in US patent 3,030,959. In the apparatus of this patent, the needles which are inserted into the tube are successively held by a ratchet device which is similar to a pencil. automatic. In addition to the problems of contamination by used needles which this apparatus leaves without release, it can be recognized that the position of the needles in the axial direction (i.e., the puncture direction) is not defined. As in the case of a mechanical pencil, the length of the protruding pencil tip can be freely selected by the user, the axial position of the needle also depends on the setting by the user. In the case of the form fit principle, the lancet and the drive unit, on the other hand, have mutually conforming attachment regions and clamping devices. By the geometric design of the clamping area and the clamping device, it can be achieved that the axial position of the lancet can be freely determined and thus the puncture depth can be accurately controlled. The use of a form fit thus avoids an axial force when engaging the lancet and the drive plunger, and an exact alignment can be achieved. With a form fit, one mold (clamping device) closes around the other mold (clamping area). Closing in this sense is understood to mean both the movement of the device parts transverse to the puncturing direction and the alternatively shaped interlocking of two shaped bodies in an unchanging shape. In a preferred embodiment the fastening device is open and closes around the fastening area when inserting this area into the fastening device. In particular, this closure is achieved with a longitudinal movement in which the longitudinal movement is converted into a movement of the fastening elements of the fastening device with a component transverse to the direction of the longitudinal movement. A practical advantage in achieving this conversion of a longitudinal movement into a transverse movement is to insert the longitudinal-movement fastening device into a converging channel (e.g. into a sleeve) or insert it into it (see FIG. 1). A convergent channel is understood here to mean not only convergent channels with a constant convergence, but generally channels whose clear width decreases

PL 196 255 B1 in the longitudinal direction. The channel does not therefore need to be a form closed on the peripheral surface. If, for example, the fastening device has two opposing hooks, as in FIG. 1, two walls are sufficient, the internal spacing of which becomes smaller.

On the other hand, it is also possible to close the fastening device by increasing the tension (see FIG. 2), which is possible, for example, by movement of the fastening device in the widening channel.

The subject matter of the invention is illustrated in the examples of embodiments in the drawings, in which: Fig. 1 shows a cross-sectional view through a lancing unit with a fastening device on the lancet;

Fig. 2 shows a cross-sectional view through part of the system with the fastening device on the drive unit;

Figure 3 is a cross-sectional view through the entire system and stages of use;

Figure 4 shows a cutout with a permanently shaped fastening device on the drive unit;

Fig. 5 shows the magazine of the lancing units;

Fig. 6 shows a system with a drive unit and a lancing unit; Fig. 7 shows a system with a shape-permanent fastening device; Fig. 8 is a force-path diagram for different types of coupling;

Fig. 9 shows a lancing unit with sterile protection; Fig. 10 shows a cylinder magazine.

Fig. 1 shows a blood collection system according to a first embodiment of the invention in operating phases I, II and III. In Figure 1, only partial aspects of the system are shown. The drawing lacks the drive unit for the pusher 10 and the housing of the drive unit in which the lancing unit 20 is mounted. As a drive unit for the pusher 10, the drive device described in EP 0 565 970 is particularly suitable.

The phases shown in Fig. 1 show the phases of the form-fit engagement between the plunger of the drive 10 and the lancet 30, and the actual piercing stage. For each of the three phases, 2 cross sections are shown along the longitudinal axis of the system perpendicular to each other. From the left representation of Phase 1, it can be seen that the lancet 30 is located within the sleeve 40. The illustrated lancet 30 has a base body made of plastic and a steel needle 31 is injection molded therein. On the side opposite the needle tip, the lancet exhibits a fastening device with fastening elements in the form of two hooks 32a and 32b. When inserting the plunger 10 into the lancet, the thickened end at the leading end of the plunger, which serves as the attachment area 11, gets between the two hooks 32a and 32b and ends up at the trailing end of the needle (phase II). It is also possible for the pusher to strike the lancet base body instead of the needle tip. Direct contact with the needle has the advantage that the length of the needle can be strictly controlled in production and thus the puncture depth can be controlled. As the plunger is further introduced, the lancet advances inside the sleeve 40 towards the exit opening 41 so that finally, the tip of the needle protrudes from the opening and pierces the underlying tissue. From the transition from Phase II to Phase II, it can be seen that the fastening devices 32a and 32b close on the lancet around the plunger attachment areas 11 as soon as the lancet passes within the sleeve 40. The lancet attachment device holds the plunger retainer such that it is formed. a form fit with which it is possible not only to move the lancet forward for the puncture, but also to substantially free active extraction of the lancet controlled by the drive unit. This is secured on the one hand by the fact that the end of the clamping area is placed over the needle end, but also by the hooks 32a and 32b which support the lower end of the clamping area from below. The length of the clamping area and the longitudinal extension of the chamber in the closed clamping device are adapted to each other so that the lancet can be driven freely in the puncture direction. By arranging the lancet or the fastening device in the tapered sleeve, the longitudinal movement of the lancet in the puncture direction is converted into a transverse movement of the fastening element which allows a form fit with the drive mounting area. As can be seen from the Figures, the sleeve 40 has a central region 40b which is tapered with respect to the top region 40a. Due to this narrowing, the lancet hooks 32a and 32b, when the lancet is inserted into the sleeve in the direction of the longitudinal axis, clamp so that the clamping area 11 is crimped. It has proved particularly advantageous to design the puncturing unit 20 so that the lancet is held in the sleeve, if not has no pusher effect. In this way it is possible to ensure that the needle is in the sleeve 40 when it is not working, and thus it will not cause any injuries or contamination from the protruding tip8

The needle. Slippage of the lancet in the sleeve towards the exit opening 41 will be effectively prevented by the fact that the hooks 32a and 32b will have a spacing that rests on the edges of the mean region 40b. The slope of these edges and the flexibility of the hooks can be adapted so that, on the one hand, the movement in the direction of the taper can be realized with little force and, on the other hand, unwanted slippage can be effectively avoided. In order to prevent the lancet from slipping out of the sleeve in the direction opposite to the puncture direction, in the embodiment shown, a flared portion 40c is provided at the lower end of the sleeve and a corresponding flared portion 30a at the lower end of the lancet base body.

As can be seen from Fig. III, the needle tip is still inside the sleeve 40 when pressing the clamping area 11 onto the needle tip. This is advantageous since the shock caused by the pressure has no effect on the formation of a puncture in the tissue, thus avoiding the pain of puncture caused by the needle. such a shock.

It is preferred according to the invention that the system is arranged such that, during the course of phases I, II and III, the return movement of the plunger 10 in the reverse direction is such that the plunger disengages from the lancet and the lancet is again completely inside the sleeve. There are two variants for coupling the plunger to the lancet. In a first variant, the housing, the drive unit and the lancing unit are so matched to each other that the pusher in the initial state is completely outside the lancing unit 20 (as shown for phase I). A disadvantage of this embodiment is that the pusher has to make a relatively long path to make the puncture. The advantage, however, is that the follower is completely outside the sleeve so that lateral movement is possible. Therefore, the first variant can advantageously be used for a system with a lancet magazine, in which successive different sleeves slide under the pusher. In a second variant, by coupling the lancing unit to the drive unit, the corresponding position is already achieved in phase II or slightly in the direction of phase III. With this embodiment, the path that the pusher has to follow can be kept very small, which is advantageous from a structural point of view.

Figure 2 shows a second embodiment of the invention, in which the lancet 130 has a clamping region 131 and the drive unit has a clamping device 132a, 132b. In Fig. 2, the area of ​​the system which serves for mounting the lancet and not for mounting the drive unit is likewise shown. Also in connection with this embodiment, it is advantageous to use a drive unit in which the follower 110 is guided. The pusher at its front end comprises a fastening device with fastening elements in the form of two hooks 132a, 132b which are connected to each other by a flexible bridge 133 (or hinge). The kit forms a spring element. In phase I, these hooks are under tension as their rear ends are held together by a sleeve 140. As the lancet 130 is advanced, the sleeve moves simultaneously with respect to the spring 141 so that the rear ends of the hooks are released and the front ends of the hooks are wrapped around the lancet attachment area 131. The lancet clamping area shows protrusions (recesses) which engage the hooks of the clamping device. The longitudinal displacement (in the puncture direction) of the intermeshed ends of the fastening device and the pulling along the extensions are essentially the same, so that a guided, substantially free, puncture movement can be performed by this setting. With this embodiment too, a conversion of the longitudinal movement of the clamping device into a lateral movement of the clamping element is realized.

Figure 3 shows a system according to the invention based on the principle of the form fit coupling according to figure 2. The drive unit 100 is based on the Softclix® apparatus which is described in EP B 0565 970. From this document it can be deduced how the rotation of the sleeve 171 transmitted by the drive spring 170 is converted into a driving motion of the follower 110. The tension of the drive spring by pressing the button 172 and the corresponding explanation of the mechanism are described in European patent application with file number EP 0010 2503.0. The drive unit has at its front end a fastening device with two fastening elements, in this specific case hooks 132a and 132b. As has already been deduced from FIG. 2, these hooks are connected to each other in a central region by an elastic bridge or by a hinge 133. On the side of the hooks facing the bridge 133 the fastening device is fastened by the sleeve such that the hooks are open. Sleeve 140 is held in position by a spring 141 located in the drive device. Fig. 3I further recognizes a lancet unit in which the lancet 130 is disposed in the cover 121. The lancet has at its lower end a clamping region 131 which is held by a clamping device 132a, 132b. The outer body of the lancet has a front narrow area and a collar 122 between this narrow area and the fastening device 131. The lancet tip is protected by the unscrewed plastic body 123 from contamination and mechanical influences. Internally, the lid 121 has a lancet passageway for a narrow area and an enlarged cross-sectional area suitable for removing the collar 122. Inside this enlarged cover channel there is a bead 124 which prevents the collar from sliding out spontaneously in the widened channel. The cover also has a sleeve 125 which serves to move back the sleeve 140 of the drive unit when attaching the lancing unit to the drive unit. This course can be followed by considering Figures 3I and 3II together. By moving the sleeve 140 away with the sleeve 125, the securing device is released to include the lancet securing region as can be seen in Fig. 3II. By pressing the button 172 and unscrewing the protective part 123 from the lancet, the system prepares for operation. By means of the device shown in Fig. 3II, a puncturing step is now performed in which the front end of the cover 120 is applied to the tissue and the drive unit is activated by pressing the release mechanism. After puncturing, the cover is pulled away from the drive unit in the direction of the longitudinal axis, the collar 122 being pulled back behind the ridge 124 so that the contaminated needle tip can no longer come out of the cover. The lancet unit of Fig. 3III can be discarded or coupled to the drive unit can be used for a further withdrawal operation.

FIG. 4 shows a third embodiment of the invention, in which the form fit between the lancet and the drive is achieved by engaging geometrically matching clamping areas and clamping devices by means of a form fit. Fig. 4A shows a lancing unit 220 which has a sleeve 240 which houses a metal needle 231. The sleeve 240 has a thin transverse wall 250 which holds the metal needle and sleeve in alignment. This wall is preferably formed during the injection molding of the needles with plastic. Due to the relatively small thickness of this wall, it is possible to disconnect the mechanical connection of the sleeve and the needle during puncturing so that the needle moves past the wall. The exit opening from the sleeve is closed by a thin foil 260 which is pierced during the puncture. At its upper end, the needle 231 carries a clamping region 232 made by injection molding. For mechanical stabilization, the needle tapers to over-mold the clamping area 232 so as to avoid axial slippage. Retention of the needle in the sleeve can be achieved by roughening the needle on the outer surface, thickening or bending the needle within the sleeve. The drive follower 210 in this embodiment has, at its lower end, a mounting device 211 which includes a mounting region 232 as shown in the form of a positive fit. The fastening device 211 is open to the side so that the pusher arranged parallel to the needle with the fastening device 211 is guided to the height of the fastening area 232 and can engage the needle fastening area by shifting transversely to the needle axis or the puncture direction. After the form fit is thus obtained, the needle can be driven both in the puncture direction by the pusher 210 and can be actively pulled back. In the example shown, the lancet attachment region has a recess (recess) in which the clamping device engages during engagement, so that the two shapes are freely joined together as far as possible in the direction of the puncture.

FIG. 4B shows a magazine that is constructed from the lancing units 220 of FIG. 4A. With reference to the coordinates shown, the follower of the drive 210 can engage with the lancet mounting region by a movement in the Y direction (perpendicular to the surface of the drawing) or lift the form fit again. With the form fit raised, the pusher of the drive can be moved in the X direction (right / left) to the height of another lancet and re-engage with it by a movement in the Y direction so that the magazine lancets can be operated successively. With a positive fit, active needle movement is possible in both the positive and negative Z direction (up / down).

As an alternative to the coupling according to FIG. 4B, which allows movement of the drive plunger in both the x and y directions, the movement of the coupling can only be carried out in the x direction. For this purpose, the drive plunger has, for example, two opposing hooks, between which a passage is provided in the x direction. lancet mounting area. By movement in the x direction, the plunger can now move from lancet to lancet to perform a puncture in the z direction. If the plunger of the drive is in the x-direction at the height of the lancet, the plunger fastening device includes a form-fit lancet attachment area and can be moved by the pusher in the direction behind the plunger, then puncture and actively withdraws the lancet as well.

Fig. 5 shows a system that works automatically with the lancing units according to Fig. 1. As can be seen from the view (Fig. 5B), the lancing units (20, 20 'etc.) have been attached.

The PL 196 255 B1 are successively on the conveyor belt. The conveyor belt 301 runs around two rollers spaced apart 302, 303. One of the rollers is motorized so that the lancing units successively pass through the engagement positions 305. In this position, as shown in Fig. 4a, engagement is possible by means of a coupling shaped follower of drive 10 with lancing unit 20 in lancing position 305.

FIG. 6 shows the drive unit with which the lancing unit is coupled in analogy to the embodiment of FIG. 1. The shown drive system corresponds to that of European Patent reference 00102503.0. With this drive system, by depressing the button 420 against the biased spring 418, the sleeve 414 rotates axially so that the second spring 415 is biased. The sleeve 414 is retained in the end position so that the second spring 415 remains under tension. If the user lifts the arresting device, the spring 415 releases and the sleeve 414 turns in the opposite direction to the tensioning sequence. The sleeve 414 has a groove which serves as a guide for the drive cylinder 408 which has a spigot or the like on its outer surface which engages with the key. The rotation of the sleeve 414 is thus converted into a motion of the drive cylinder. The drive cylinder transmits its movement to a drive follower 480 which has a mounting area at its front end.

The drive unit further has a mounting area 450 onto which a lancing unit can be attached or screwed on. The lancing unit holds a cover 470 which has a surface for pressing against the skin surface. Included in the cover is a sleeve 471 which exhibits a lancet 472 with a fastening device on its side facing the needle tip. The lancet fastening device corresponds to the fastening devices 32a, 32b of Fig. 1. From figure 5, it can then be seen that the lancet form fitting to the plunger of the drive is already achieved by applying the cover 470 to the drive device.

Figure 7 shows a system for withdrawing bodily fluids which has many similarities with the system of Figure 3. In particular, we would like to refer to the description of the drive and tensioning mechanism given for Figures 3 and 6. The system of Figure 7 has a lancing unit 120 '. with cover 121 'and lancet 130'. The cover 121 'has an axial passage through which the lancet body can pass when a puncture is made. Preferably, both the passage and the lancet body are adapted to each other such that the axial guidance of the lancet during puncturing is carried out with only a very slight lateral movement. At its rear end, the cover has a thread 126 which can be screwed into a corresponding thread 127 of the drive unit 100 '. At the end opposite the needle tip, the lancet has one or more (in the illustrated case 2) plugs 131 'which penetrate into the form fit of the fastening device 132' when the cover is placed or screwed onto the drive unit. For this purpose, the drive device has openings or slots which show an axial portion 134a and a portion 134b arranged perpendicular thereto. When the cover is placed on the drive unit, the pins 131 'extend into the axial portion of the recess 134 and pass through it up to the height of the transversely arranged portion of the recess. By screwing the cover 120 'onto the drive unit 100' the pins 131 extend from the end of the axial portion to the transverse portion of the recess as far as the opposite end. As can be seen in Fig. 7II, the lancet is held axially by the pins by the clamping device 132 'so that a guided puncture movement by the lancet can be achieved. By inserting the pins into the transverse part of the recess, a movement with the lancet can be made both in the direction of extension of the needle tip and of retraction. As can be seen from figure 7, a form fit connection can be achieved between the lancet and the clamping device without a ratchet or clamp. The principle of coupling shown in Fig. 7 from the lancet and the drive plunger is of course also reversible, i.e. it is also possible by means of a suitable clamping device on the lancet and the clamping area on the plunger or drive.

FIG. 9 shows a further development of the system of FIG. 1. The drive follower 10 'has a mounting area 11' which in its upper steep has an oblique surrounding surface, which, as can be seen in FIG. 9B, fits into the oblique surface of the hooks during puncturing. 32a ', 32b'. The end of the pusher of the drive rests on the end of the needle and acts on the flexible hooks 32a ', 32b' when pressed against each other, so that the bevels on the inside of the hooks press against the bevels on the top surface of the mounting area so that the mounting area presses against the end of the needle and the lancing device forms easy connection between the clamping area and the lancet. By such a fit, a very precise retention between the lancet and the drive plunger can be achieved by means of a form fit which aligns manufacturing tolerances so that play is avoided both during puncture and during the return movement.

Fastening device in the form of hooks 32a '. 32b 'is further shaped such that the free ends of the hooks engage openings in the sleeve 40'. This avoids that the lancet 30 'could slip unnecessarily out of the sleeve 40'. As can be seen from the transition from Fig. 9A to Fig. 9B, the free ends of the hooks at the start of the pricking step first release from their slots and on sliding the hooks are pushed into the tapered sleeve so that they engage the drive pusher attachment area.

From Figure 9, it can further be seen that the needle tip 31 'is disposed in the material 35. The material is preferably an elastomer which tightly surrounds the needle tip so as to effectively prevent fouling of the needle tip. Suitable elastomers are styrene oligoblock copolymers, thermoplastic polyolefins, thermoplastic polyurethanes, thermoplastic copolyesters and thermoplastic copolyamides. For further details on lancet tip contamination, reference is made here to International Application WO 01/66010. In the starting position according to Fig. A before puncturing, the tip of the needle is in the elastomer and when the puncture is made it is pierced by the needle as can be seen from Fig. B. For this purpose, the sleeve 40 'has a plate 36 on its lower side with a central opening. The plate prevents the elastomer from exiting through the orifice so that it is pierced when the needle exits through the central orifice.

When the lancet is pulled back, the elastomer remains on the needle with the needle tip now free (see Fig. C).

FIG. 10 shows in section (FIG. A) and in perspective view (FIG. B) the cylindrical lancet magazine according to FIG. 1 or FIG. 9. With such a magazine it is possible to couple new lancets to the drive in a simple manner. For this purpose, the pusher of the drive can, for example, be permanently attached to the puncture site and the cylinder magazine shown in Fig. 10 it can rotate similar to the barrel of a revolver so that unused lancets are brought into engagement with the drive follower.