Blood lancet device for obtaining blood samples for diagnosis purposes

The invention relates to a blood lancet device for Withdrawing blood for diagnostic purposes, comprising a housing with an outlet opening for the tip of the lancet, one in the housing along a predetermined straight Puncturing movable lancet holder for holding the Lancet and a lancet guide, by which the lancet holder is guided on the predetermined puncture path, having.

To get a drop of blood, the blood lancet device is surrounding with the outlet opening Contact surface against the skin (especially on the fingertip or an earlobe) pressed and a puncturing process triggered, wherein the lancet holder and held therein by a lancet in the blood lancet device existing lancet drive with a high speed along the predetermined puncture in Direction of needle is moved until its tip from the Exit orifice exits the extraction of the Blood drop required to produce wound. After that is the lancet holder by the lancet drive in returned a position at which the tip of the Lancet located in the housing.

Lancet devices are in many embodiments known. Most of the lancet drive is formed by a simple mechanism in which the Lancet holder propelled directly by a linear spring is and the closest point of exit width of the lancet tip impinges on a stop. This enables us stopped the lancet jerky and by the spring action returned to the starting position. Such blood lancet device is easy to produce, in the Function but not optimal, in particular because of the case Pain caused the puncture is relatively large.

The reduction caused by the production of the wound Pain, however, is of great medical importance. This is particularly true for diabetics who their Blood sugar levels frequently and regularly to the necessary insulin injections to the needs (of of food intake, physical activity and other Factors dependent) adapt, leading to blood sugar levels continuously if possible within certain Set limits to keep. This is for the health of such Patients and serious for the avoidance Late damage such as blindness, of paramount Importance. was in extensive investigations found that by close control of blood glucose levels serious long-term damage of diabetes Mellitus can be dramatically reduced.

A painless blood sampling allow blood lancet device, in which the relaxation movement of the drive spring by means of a rotary drive rotor in the puncturing movement is implemented. As a result, with the Impact of the lancet holder connected to a stop Vibration avoided.

A blood lancet device with such a rotor drive is described in US Patent 4,924,879. there the rotor is driven by a coaxial spiral spring. The rotational movement of the rotor through a connecting rod in the required linear movement of the lancet implemented.

In the lancet device described in U.S. Patent 5,318,584 the drive rotor rotates about a to the puncture direction parallel axis of rotation. Also in this Case, it is driven by a coaxial spiral spring. The conversion of the rotational movement in the required Linear movement of the lancet holder by means of a Rotational shift transmission, preferably by means of a cam control is realized. In this case, the rotor has a Recess, into which a suitable control pin of the The lancet holder engages. By this construction a very good penetration behavior with low vibration achieved and a precise reproducible puncture depth. This is associated with the production of the wound Pain very low. A disadvantage, however, is that the construction is relatively complicated, the precise interaction requires shaped components. The production is therefore complicated and expensive. reliable Function assumes a precise manufacturing.

The invention is based on this basis the object of a blood lancet device available to provide, in a precise and vibration-free injection behavior reduced production costs and Accordingly, a reduced cost is achieved.

The object is at a blood lancet device of type explained with rotor drive the lancet holder achieved in that the drive rotor to a has radially outwardly directed pressure surface, which in varying Axial distance such to the axis of rotation runs round it a vertex with maximum Wheelbase and a vertex opposite to the Rotational direction following propulsion section counter with the rotational direction of decreasing axial distance which the is driving spring designed so that they in a propulsive rotation angle range the drive rotor via a Pressure element a pressure with a radially towards the rotational axis directional component of the propulsion section the pressure surface exerts, so that the drive rotor by the pressure of the drive spring on the Printing area in the driving section in the direction of rotation is driven, and the drive rotor about an output-side Coupling mechanism with such the lancet holder is coupled to the tip of the lancet exiting from the exit opening, while the drive rotor located in the propulsion angle of rotation range.

The drive rotor with radially outward (away from the Rotation axis) directed pressure surface can be easily produced as a plastic part. The power transmission from the drive spring in the rotational movement of the drive rotor (Hereinafter referred to as the "drive-side coupling mechanism the lancet drive "hereinafter) is by the shape of the propulsion portion of the pressure surface certainly. Different configurations of the Printing area can consequently various desired movement characteristics of the drive rotor (rotational speed adjusted as a function of the angle of rotation) will. An advantageous has a shape proved, in which the propulsion section is at least partially is convexly curved.

To tighten the drive rotor has moved to a position be, wherein the pressure element of the near Vertex lies on the printing surface. This can be effected with different clamping mechanisms. Preferably carried out not only the drive of the puncturing movement, but also the tensioning of the lancet drive by cooperation of the spring and the pressure surface, wherein the pressure surface a tension section with counter the rotational direction of increasing axial distance has. Also the clamping portion is preferably at least partially convexly curved.

According to a further preferred embodiment, the output-side coupling mechanism by which the rotational movement the drive rotor in the puncturing and return movement the lancet holder is transferred, by A together with the drive rotor rotatable, a Cam formed recess forming, in which a with the lancet holder associated control pin engages. With this construction, the design of the Cam and the output-side coupling mechanism varies according to the desired penetration behavior will. Thus extensive opportunities that arise Velocity profile of the puncturing movement (depending the instantaneous speed of the position of the lancet holder) with regard to the lowest possible optimizing pain. A particularly simple design is achieved if the forming the control curve recess is formed in the drive rotor.

The invention is described based on the figures in Embodiments illustrated explained in detail. The it describes peculiarities can be used individually or in Combination can be used together to preferred Embodiments of the invention to provide. Show it:<dl tsize="7"><dt>Fig. 1</dt><dd>a longitudinal section through an inventive Blood lancet device during insertion a lancet into the lancet holder;</dd><dt>FIG. 2</dt><dd>a longitudinal section through the device according to Figure 1 in the rest position of the lancet drive.</dd><dt>Fig. 3</dt><dd>a longitudinal section through the device according to Figure 1 in the cocked position of the lancet drive.</dd><dt>Fig. 4</dt><dd>a longitudinal section through an alternative embodiment of a blood lancet device in the rest position;</dd><dt>Fig. 5</dt><dd>a longitudinal section through the device according to Figure 4 is in the cocked position of the lancet drive.</dd><dt>Fig. 6</dt><dd>a side view of the drive rotor of the device of FIGS. 4 and</dd><dt>Fig. 7</dt><dd>a side view of the clamping lever of the device of Fig. 4.</dd></dl>

In the housing 1 to that shown in FIGS. 1 to 3 Blood lancet device 2, a lancet holder of 3 a total designated 5 lancet drive such driven to a fixed in the lancet holder 3 Lancet 6 performs a puncturing motion in its tip 7 of a outlets opening 8 of the housing 1 leaking to adjacent one in at the outlet opening 8 Part of the body 9 (Fig. 3) to generate a wound. The to be applied to the body part 9 provided the outlet opening surrounding area is a contact surface 10 designated. The puncturing and returning motion of the lancet holder 3 is of a case in the illustrated by plastic webs 12 formed lancet guide 13 precisely guided on a linear straight puncturing path, so that practically no vibrations having components of motion perpendicular to the symbolized in Fig. 1 by the arrow 14 can puncture direction occur.

The lancet drive 5 consists essentially of a about an axis 15 rotating drive rotor 16 and a Drive spring 17, which in the case shown as a Fixing post 19 coiled torsion spring having two limbs 20, 21 are formed.

The drive rotor 16 has a radially outwardly directed Pressure surface 23, which in a varying center distance extends around the axis of rotation 15 around. A first Leg 20 of the drive spring 17 exerts a pressure element 24 is a pressure with a radially toward the Axis of rotation 15 directed components to the printing surface 23 out. This pressure transmission should be as be frictionless. Therefore, the pressure element 24 as at the end of the first leg 20 mounted on the Face 23 running wheel 25 is formed. The second Leg 21 is outside the rotation range of the drive rotor 26 16 is fixed.

The drive rotor 16 is 3-strahligsymmetrisch with Axis 15 as center of symmetry, so that its shape elements Repeat in a rotational angular distance of 120 °. The pressure surface 23 is in the drawing plane of Figures 1 to 3, with the plane of rotation of the drive rotor 16 coincides approximately triangular. Your (slightly rounded) Corners form apexes 27, the maximum the Distance of the pressure surface 23 from the axis of rotation 15 mark. Adjoining the vertices 27 contrary to the direction of rotation indicated by the arrow 28 the drive rotor 16, a section with decreasing center distance to which called propulsion section 30 becomes. The vertices 27 (relative to the direction of rotation 28) precede each portions of the pressure surface 23 where the axle decreases in the rotational direction (ie counter the rotational direction increases) and as clamping portions referred to 31st Overall, the pressure surface 23 between the apexes 27 in the plane of rotation slightly convex curved.

In order to cock the lancet drive 5, the lancet rotor must 16 from the rest position shown in FIG. 2 in Direction of rotation 28 is rotated and thereby shown in the FIG. 3 cocked position be brought. This can for example by means of an electric rotor drive happen. but is preferably a mechanical tensioner. It has in the case shown a clamping lever 33, of a torque in the direction of rotation 28 a rotor provided on the drive abutment portion 34, the in the case represented by cylindrical, of the End face of the drive rotor 16 formed projecting pins is exerting. The clamping lever 33 is composed of a in the quiescent state (Fig. 2) laterally from the housing 1 outstanding operating button 35 and in the housing 1 extending arm 36. Between the actuating button 35 and the swing arm 36 is a located Pivot 37, the axis thereof to the rotation axis 15 the drive rotor 16 parallel. To tighten the Lancet drive 5 is the operating button 35 in the direction of the arrow 39 is pressed into the housing. Thereby pivots the pivot arm 36 upwards and at the end of Swing arm 36 provided hook 40 detects one of the Abutment parts 34, so that the rotor 16 in the rotational direction 28 is rotated. Here, the pressure element 24 drives a Clamping portion 31 of the pressure surface 23 from. The distance the pressure element 24 from the axis of rotation 15 increases, the drive spring 17 is gradually stretched, until their first leg 20 by dashed lines in the (in Fig. 2 shown) position of maximum distance from the axis of rotation 15 is located. When the lancet drive 5 is fully tensioned, there is the drive rotor 16 in the illustrated in Fig. 3 position in which the pressure element 24 against an apex 27 of the Face 23 presses.

Once the lancet rotor 16 is further rotated in the direction of rotation 28 is reached, the pressure element 24 in the propulsion section 30 of the pressure surface 23. Thus begins a rotation angle range the movement of the drive rotor in which the Pressure of the drive spring 17 (which is substantially the Rotation axis 15 is directed, at least one component in this direction has) converted into a torque is driving the drive rotor 16 in the rotational direction 28th This rotation angle range in which the pressure element 24 is in contact with the driving portion 30, is called propulsive rotation angle range.

The drive spring 17 with the pressure member 24 and the Face 23 as a whole constitute a driving side Coupling mechanism by the rotation of the drive rotor 16 is produced, which in the propulsion rotation angle range quickly and automatically (without in this Movement phase a user interaction or possible is required) expires. To this rotary movement in the required linear movement of the lancet holder 3 with implement the lancet 6, an output-side coupling mechanism necessary, the different Manner can be realized. For example, a Pleuelmechanismus, as in U.S. Patent 4,924,879, is suitable.

However, preferably, the embodiment shown in the figures, in a together with the drive rotor 16 rotatable, preferably in the drive rotor 16 self-educated, formed by a recess 41 Cam 42 is provided in the one with the lancet holder 3 associated control pin 43 engages so that at least a part of the puncturing and return movement by the rotation of the cam 42 relative to the Control pin is determined. In this case the control pin moves the cam from 42nd The maximum displacement of the lancet holder 3 in the puncture direction is through a lower Reversal point 44 of the cam 42 determines the so is positioned to be inside of the control pin 43 the drive-rotation angle range of the rotor movement is executed. The control peg is preferably immediately on the lancet holder 3 (namely, at the of the lancet tip 7 averted end) attached.

To the insertion of the lancet into the lancet holder 6 3 easier, is provided at the lower end of the housing 1 a lower end part 46 provided that an elongated Shape with parallel to the rotor plane (ie in the plane of the drawing of Figures 1 to 3) extending major axis Has. It is one-sided on one of its narrow sides 46a pivotally (via a hinge 47 with parallel to the rotor axis extending pivot axis) of the remaining housing articulated. To insert the lancet is the lower End of the housing 1 by pivoting the lower end portion 46 (Fig. 1) opened so that the lancet holder 3 is easily accessible. The lancet 6 is at a their top 7 covering cap 48 taken and in the lancet holder 3 inserted. For more details via suitable lancet holders are U.S. Patent 5,318,584 and the references cited therein for remove.

The lower end part 46 is provided with an arm 49 coupled, the opening of the end part 46 with a Boom 55 collides. The boom 55 acts with the Lancet holder 3 such composition that an inserted therein Lancet due to the collision with the pivot arm 49 automatically when the end part 46 of the lancet holder 3 is ejected.

To adjust the penetration depth is at the hinge 47 opposite narrow side of the lower end part 46 an adjusting device 50 is provided, by the distance (in the puncturing direction) between the lower end part 46 and the rest of the housing 1 set can be. The larger this distance, the is lower (with the natural path of movement of the lancet holder 3) the penetration depth. To set the adjustment device 50 is a thumbscrew 51, which through an opening provided in the housing not shown recess accessible from the outside is.

The embodiment illustrated in Figures 4 and 5 response compared to the illustrated in FIGS 1 to 3 Lancet device a slimmer and more compact Housing shape, but right in the technical features largely with this agreement, which have the same function refers to components with the same reference numerals are.

A special feature is that the drive rotor 16 in this embodiment is 2-strahligsymmetrisch. His face 23 thus has two vertices 27 with each subsequent propulsion and Clamping portions 30 and 31 will result a smaller Design is possible, wherein the rotor 16 particularly compact can be made when the position of the pressure element 24 with respect to the longitudinal axis of the lancet holder 3 is laterally offset. Thereby, it is possible to Cam 42 to orient so that their lower turning points 44 based on the rotation axis 15 as in the same direction as the apexes 27 of the Pressure surface 23 are oriented, and at the same time the condition observed that the control pin 43 the lower reversal point 44 within the propulsion rotational angle range the drive rotor 16 leaves.

Another special feature of the figures 4 and 5 Embodiment is based on the figures in the 6 and 7 components separately shown clearly. While in Figures 1 to 3, the printing surface 23 in the Around the vertices 27 continuously convex curvature is such that the tensioning movement upon actuation of the clamping lever 33 without stopping in the propelling movement of the drive rotor 16 passes, has the drive rotor shown in Figure 6 at its vertices 27 each have a small recess 52 which is formed so that the Pressure element 24 snaps in. To get out of this position out the transition to the propulsion angle of rotation range the rotor movement and thus trigger the puncturing movement, an additional tripping mechanism is provided, the additional two in the case shown abutment parts 53 of the drive rotor 16 and a special realized design of the swing arm 36 of the clamping lever 33 is. These elements are adapted to one another, that the engagement between the swing arm 36 and that of this operated abutment portion 34 is interrupted at the moment is, in which the pressure element 24 in the recess 52 clicks. By briefly releasing and re Pressing the button 35 is the swing arm 36 in engagement This with an additional abutment parts 53. the puncturing motion is triggered.

Numerous other embodiments of the invention are possible. The drive rotor is preferably N-strahligsymmetrisch (N = 2,3,4). Basically, however, is also a not symmetrical configuration possible. Especially , a drive rotor having only one vertex and one about cam-shaped design of the pressure surface 23 be used. The pressure surface 23 is preferably a continuously steady, completely surrounding the axis Area. However, it may also be interrupted, if ensured by other constructive measures is that of the drive rotor reaches a state in where the pressure member 24 in the vicinity of a Vertex 27 is adjoined by a driving section connects with the described characteristics. In Usually, the pressure surface 23 a by movement of a Lines generated in the space area (ruled surface), wherein the generatrix parallel to the axis of the drive rotor runs. However, it is also a certain tendency or Curvature of the face 23 possible that they allow the Described functions can not be prevented.

The invention combines the advantages of a simple and robust mechanical components with a high-precision lancet guide. They can be realized with few components and easy to be assembled. Most parts are made of Plastic and can cost in large numbers - Be prepared - especially by spraying. The Drive spring is made of spring steel and has a simple Geometry, which is also cost-effective production allowed.