Medical fluid pump having a drive head

Abstract

The invention relates to a medical fluid pump, in particular a syringe pump, having: a housing (6) in which a syringe cylinder (14) is able to be received; a securing device for securing a syringe plunger rod (16) and / or the syringe cylinder (14); and a drive device for bringing about a controlled relative movement, directed in the axial direction (A14) of the syringe cylinder (14), between the syringe cylinder (14) and syringe plunger rod. For improved securing of the syringe plunger rod (16), the securing device is formed by multiple blades (30) which, in the manner of a central or bladed shutter (LV) known from camera technology, are grouped concentrically about a shutter axis that is able to be oriented with respect to the axis (A14) of the syringe cylinder (14) and are movable synchronously by means of a drive device for securing the syringe plunger rod (16) in order to change the central clearance between the blades (30).

Description

[0001] Medical fluid pump with one drive head

[0002] Description

[0003] The present disclosure relates to a medical fluid pump, in particular a syringe pump, which may be equipped with a drive head.

[0004] Developments in modern medicine, particularly intensive care medicine, have led to infusion therapies that require the targeted delivery and precise dosing of highly effective medications via fluid pumps. A very commonly used fluid pump design for this purpose is the so-called syringe pump. Syringe pumps are used in medicine to deliver a defined dose of medication to patients from a syringe. The syringe is automatically extruded at a specific rate to deliver a defined amount of medication to the patient over a defined period of time. Such medical fluid pumps are available in a wide variety of designs.What they have in common is that they have a housing for receiving a syringe cylinder, a fixing device for fixing a syringe piston rod, and a drive device for effecting a controlled relative movement between the syringe cylinder and the syringe piston rod in the axial direction of the syringe cylinder.

[0005] According to a variant on the market in which the syringe plunger rod is driven, a filled syringe cylinder is inserted into the syringe pump and the free end of the extended syringe plunger rod is secured using a drive head attached to a holding / drive arm. The end section of the syringe plunger rod must be held in place by a fixing device, often driven by a motor, which is usually done by pivoting, angled clamp-like arms or claws on the drive head. Furthermore, the drive head should be provided with a device that makes it possible to measure the force that a pump drive exerts on the syringe plunger via the drive arm and the drive head mounted on it. One of the purposes of this type of force monitoring is to be able to quickly detect blockages in the fluid path between the syringe and the patient.Syringe pumps are known, for example, from EP 0 566 825 A1 or EP 1 329232 B1.

[0006] This well-known claw mount allows syringes of different sizes to be securely held in place. However, when very small syringes with correspondingly small syringe barrels 14 are to be secured, inaccuracies in the axial fixation become increasingly apparent.

[0007] It is therefore an object of the present disclosure to further develop a medical fluid pump of the design described above in such a way that the fixing device is able to fix fluid pumps or syringes in a wide size range more effectively and securely.

[0008] This object is achieved by a medical fluid pump, in particular a syringe pump, having the features of claim 1.

[0009] The fixing device is formed by a plurality of blades which, in the manner of a central or leaf shutter or an iris diaphragm known from camera technology, are grouped concentrically around a shutter axis parallel to the movement axis of the drive arm. By means of the drive device, which can be operated manually or motor-driven, they can be moved synchronously with the change in the central free space between the blades. The opening remaining between the blades in the center can be varied in such a way that, regardless of size, it is always almost circular and the center point remains constant. In the open state, i.e. in a state in which the blades are shifted radially outwards, the free end of the extended syringe plunger or syringe piston rod can be inserted into the drive head.By motor drive, manually, or by spring force, the slats can now be moved synchronously radially inward until they hit the contour of the syringe plunger rod. Due to the design of the slatted closure, the slats always remain uniformly and concentrically grouped around the closure axis, and the slats are moved radially inward until the slats define the smallest possible opening of the slatted closure, namely the opening that touches the contour of the syringe plunger rod or the contour of a plunger plate. This results in improved, i.e. more secure fixation over the entire circumference of the syringe plunger rod or a syringe plunger plate carried by it, with the particular advantage that this fixation is independent of the size of the inserted syringe.

[0010] This concept can be used particularly advantageously in medical fluid pumps in which the housing is designed to accommodate syringe barrels of different sizes, and in which the fixing device is accommodated in a drive head which is movable linearly along a movement axis via a tubular or rod-shaped drive arm to the housing. In this case, it is particularly advantageous to design the arrangement according to claim 2, i.e. to arrange the lamella closure in such a way that the closure axis is guided so as to be movable linearly and perpendicular to the movement axis of the drive arm, preferably free from friction or constraining forces, in a plane spanned by the axes of the syringe barrels of different diameters positioned in the housing.Because the closure axis is free of constraint forces and the contour of the syringe piston rod is axially or rotationally symmetrical, the closure axis aligns with the axis of the syringe piston rod during the closing movement of the lamella closure, whereby syringes of different sizes or circumferential contours can be fixed precisely and free of tension in the medical fluid pump.

[0011] Advantageous embodiments are the subject of further subclaims.

[0012] The slats can be formed from bodies of various shapes, i.e., contours and thicknesses. If they are plate-shaped, the slatted shutter takes up a compact installation space.

[0013] Typically, a louvre shutter is designed so that the louvres can be rotated inward or outward together via a mechanism. Each louvre is mounted on an axle, and all louvres are connected to a ring via another axle so that they move together. The more louvres used, the more circular the opening becomes. To keep the design of the drive head as simple as possible, it is advantageous if the central or louvre shutter is formed by a module that can be incorporated into the drive head.

[0014] The linear mobility of the shutter axis can be ensured in various ways. If the module of the lamella shutter is movably guided in the drive head, the moving mass remains relatively small.

[0015] On the other hand, the design of the drive head is simplified if the central or louvre shutter is fixedly mounted in a drive head, and the latter is movably connected to a drive arm. A further advantage of this design is that in this case, a piston pressure sensor can also be fixedly mounted behind the louvre shutter, concentric with the axis of the louvre shutter.

[0016] It is further advantageous if the drive mechanism is formed by a rotatably mounted adjusting ring. Such an adjusting ring can be easily accommodated within a drive head, and the drive force required to move the slats can be kept relatively low. This opens up the possibility of preloading the slats into the closed position using a compact spring mechanism, from which they can be manually moved to the open position.

[0017] However, the operational advantages of the medical fluid pump arise when the adjusting ring is motor-driven, with the drive motor also housed in a drive head. Due to the small masses to be moved, such a motor can be designed with a very small volume, allowing it to be conveniently housed in the housing of the drive head.

[0018] A particularly advantageous embodiment of the syringe plunger fixation results from the development of claim 6, according to which the lamellae each have a beveled surface, at least in a radially inner region on their side facing away from the housing, which can be brought into contact with a collar of a plunger rod head when a syringe is inserted. With this design, the syringe plunger can also be fixed in the axial direction without play, for example in a drive head, which makes it easier to initialize the measuring system for the force applied to the syringe plunger and improves the accuracy of the syringe plunger control. The resulting axial freedom from play is also advantageous for ensuring constant delivery under changing pressure conditions (positive or negative holding pressure due to changes in the height of the pump relative to the patient).

[0019] In principle, the number of lamellae can be varied within wide limits. The lamellae can also overlap each other. However, if the lamellae are assigned an axial stabilizing function for the syringe plunger, it is advantageous for the lamellae to lie in a common plane. This has the additional advantage that the lamellae can be made thicker and thus more robust.

[0020] Medical fluid pumps are regularly operated in an environment that cannot be kept free from fluid splashes. The fluids administered with the syringes often contain substances, such as glucose, which can impair the mechanics of the fixation device, for example, causing it to stick. To prevent such impairments, it is advantageous to provide the lamellae with a fluid-repellent coating.

[0021] Particularly effective protection of the mechanical components of the slatted shutter is achieved when the slats are covered by an elastically stretchable sleeve.

[0022] If the medical fluid pump has a sensor that detects the opening width of the lamella closure, the sensor's output signal can be used to identify the type and / or size of the inserted syringe. Another advantage of the lamella closure used in the invention is that small actuating forces are generally sufficient for the synchronous movement of the lamellae, thus even opening up the possibility of using a motor drive for the lamella closure via magnetic force coupling.

[0023] Exemplary embodiments of the invention are explained in more detail below using schematic drawings. They show:

[0024] Fig. 1 is a perspective view of a medical fluid pump according to a first embodiment of the present disclosure in the form of a syringe pump with a closed cover or front flap;

[0025] Fig. 2 is a perspective view of the syringe pump shown in Fig. 1 with the front flap in the open position;

[0026] Fig. 3a and 3b are schematic partial views of a first embodiment of the medical fluid pump with inserted syringes of different sizes;

[0027] Fig. 4a and 4b are schematic partial views of a second embodiment of the medical fluid pump with inserted syringes of different sizes;

[0028] Fig. 5a and 5b are perspective views of the fixing device for a syringe plunger rod in the form of a lamella closure with a representation of syringes of different sizes;

[0029] 6a to 6c are schematic views illustrating the components of a lamella closure used in a medical fluid pump according to the invention;

[0030] Figs. 7 to 9 are schematic views of variants of a lamella closure used in the medical fluid pump, with variants of lamellae; Fig. 10 is a sectional perspective view of another embodiment of a lamella closure with a fixed syringe plunger head;

[0031] Fig. 11 is an enlarged view of the slatted closure according to Figure 10 with the slats retracted;

[0032] Fig. 11a and 11b are perspective views of a slat used in the slatted shutter according to Fig. 10 and 11;

[0033] Fig. 12 is a schematic view of the slatted shutter with drive motor shown in Figures 10 and 11;

[0034] Fig. 13a and 13b are perspective partial views of the medical fluid pump according to Fig. 3a and 3b to illustrate the linear mobility of the lamella axis according to a variant;

[0035] Fig. 14a and 14b are perspective partial views of the medical fluid pump according to Fig. 4a and 4b to illustrate the linear mobility of the lamella axis according to a modified variant;

[0036] Fig. 15 shows, on an enlarged scale, a perspective sectional view of a detail of Figure 14a to illustrate the linear guidance of the slatted shutter in the drive head;

[0037] Fig. 16a and 16b are enlarged views of the medical fluid pump according to Fig. 13a, 13b, viewed along the axis of the syringe barrel;

[0038] Figs. 17a and 17b are enlarged views of the medical fluid pump according to Figs. 14a and 14b, viewed along the axis of the syringe barrel; Figs. 18a and 18b are schematic views of the drive head housing to illustrate a further modified embodiment of the fixing device for the syringe plunger rod;

[0039] Fig. 19a to 19c are schematic views of the principle of a slide guide which can be used for the linear mobility of the lamella shutter axis;

[0040] Fig. 20 and 21 are schematic views of the drive head housing to illustrate two further modified embodiments of the fixing device for the syringe plunger rod; and

[0041] Fig. 22A and 22B are enlarged perspective views of a modified leaf shutter based on a leaf shutter LV according to Fig. 10.

[0042] Detailed description of preferred embodiments

[0043] Fig. 1 and Fig. 2 show a perspective view of a medical fluid pump in the form of a syringe pump, which is designed with a motor-driven drive head. However, it should be emphasized at this point that the concept according to the application is suitable for all types of medical fluid pumps that have a housing in which a syringe barrel can be accommodated, a fixing device for fixing a syringe plunger rod, and a drive device with which a controlled relative movement in the axial direction of the syringe barrel can be effected between the syringe barrel and the syringe plunger rod.

[0044] Fig. 1 shows the medical fluid pump 2 with a front flap 4 in a closed position. The front flap 4 typically has a display 5 on its outside. Fig. 2 shows the device 2 with the front flap 4 in an open position.

[0045] The medical fluid pump 2 has a substantially cuboid-shaped housing main body 6. The front flap 4, with which a receiving area 8 can be closed, is arranged on a long side surface of the housing main body 6, which side surface faces a user in the operating position of the medical fluid pump 2. The front flap 4 is pivotally connected to a long edge of the main body 6 via a hinge device 11. On an inner side of the front flap 4, on a long edge opposite the hinge device 11, spring clips 13 are provided, by means of which the front flap 4 is clamped to the main body 6 in the closed position. Magnets can also be used instead of spring clips.

[0046] To the side of the display 5 on a side wall of the housing main body 6 there is a drive head 10 which is arranged essentially perpendicular to the side wall of the housing main body 6 and which can be extended and retracted essentially perpendicular to the side wall of the housing main body 6 via a holding drive arm 18 which is not visible in Figures 1 and 2 but is shown in Figures 3 and 4.

[0047] The receiving area 8, also referred to as the syringe recess, is designed to laterally hold syringe cylinders 14 (not shown) of different sizes—as schematically illustrated in Figures 3 and 4—in a manner that allows the respective syringe plungers to be displaced via syringe plunger rods 16 by means of the drive head 10, which serves as a stop for the syringe plunger. For this purpose, the drive head 10 is moved by means of a drive integrated in the main housing body 6 via a tubular or rod-shaped drive arm 18, specifically linearly along a movement axis A18. To simplify the reception of the syringes, a push button 12 can be provided on the drive head 10. When pressed down, this push button releases the drive head 10 from the drive so that it can be moved manually. Instead of a push button, a syringe clamp can also be provided to fix the syringe cylinder in the syringe recess.This syringe bracket can be pulled out and folded to the side by 90 degrees when the drive head is extended.

[0048] To start up the syringe pump 2, the front flap 4 is first opened and a syringe (not shown) with a filled syringe barrel 14 is inserted into the receiving area with the axis A14, as shown schematically in Figure 3. The housing 6 of the medical fluid pump 2 is only indicated schematically in Figures 3 and 4. During insertion, a shoulder section 20 of the syringe barrel 14 is placed on the housing main body 6 and the syringe barrel 14 is brought into contact with the inner wall of the receiving area 8. By means of a holding device (not shown) or by closing the front flap 4, the syringe barrel 14 is positioned in the housing main body 6 as shown in Figures 3 and 4. With the drive arm 18 extended, the free end of the extended syringe piston rod 16 must now be fixed in the drive head 10. The fixing device developed for this purpose is described in more detail below with reference to Figures 5 ff.

[0049] It can be seen from the illustration in Figures 3 and 4 that when positioning syringes of different sizes, the plane spanned by the axis A14 of the syringe cylinder 14 and the movement axis A18 of the drive arm 18 does not change. Only the lateral distance of the syringe piston rod 16 from the drive arm 18, i.e. the lateral distance between the axes A14 and A18, changes, namely between a value AG for a largest syringe (Figures 3a, 4a) and a value AK for the smallest syringe to be inserted (Figures 3b, 4b). Accordingly, the fixing device for the free end of the extended syringe piston rod 16 must also be linearly movable with respect to the drive arm 18 in the plane spanned by the axes A14 and A18, so that the syringe piston rod 16 can be moved by the drive head 10 without being subjected to bending forces.The linear mobility should preferably be designed in such a way that frictional forces are as low as possible and that the fixing device can align itself as freely as possible from constraining forces.

[0050] Figures 3a and 3b show a variant in which this mobility is provided by the drive head 10 being connected to the drive arm 18 in a linear manner perpendicular to the axes A14, A16. This linear mobility is indicated in Figures 3a and 3b by the solid double arrow LB and lies in the plane E, which is spanned by the axes A14 of the syringe cylinders 14 of different diameters positioned in the housing. According to an alternative variant, shown in Figures 4a and 4b, the drive head 10 is fixedly attached to the drive arm 18. The fixing device for the free end of the extended syringe piston rod 16 obtains its linear mobility perpendicular to the axes A14 and A18 by being accommodated in a displaceably guided manner within the drive head 10. This mobility is indicated in Figures 4a, 4b by the dashed double arrow LB.

[0051] The structure of the fixing device is described in more detail below with reference to Figures 5 ff.

[0052] As shown in Figures 5a and 5b, the fixing device is formed by a plurality of plate-shaped slats 30 which, in the manner of a central or slatted shutter LV known from camera technology and designed as a shutter module in Figures 5a and 5b, are grouped concentrically around a shutter axis A30 parallel to the movement axis A18 of the drive arm 18 (not shown in Figure 5), and which can be moved synchronously with the change in the central free space between the slats 30 by means of a drive device to be described further below. The slats 30 are circumferentially centrically positioned against the contour of the syringe piston rod 16, which has a cross shape in the illustrated embodiment, while the shutter axis A30 is aligned with the axis A14 of the syringe cylinder 14 and the syringe piston rod 16 essentially free of constraining forces due to the linear mobility LB in the plane E.The syringe is thus fixed by the drive head 10 in such a way that the syringe plunger rod is free from bending stresses. In this position, the drive head 10 can be driven via the drive arm 18 to empty the syringe cylinder 14 in such a way that the feed force acts precisely centrally on the syringe plunger rod 16. This, in turn, makes it possible to control the dosage of the active ingredient held in the syringe cylinder 14 with the greatest possible precision.

[0053] The number and shape of the slats 30 used for the slatted shutter can be varied within wide limits. Figures 6 to 9 show some possible embodiments of a usable slatted shutter by way of example. What all embodiments have in common is that - as shown schematically in Figures 6a to 6c - the slats 30 can be rotated jointly and synchronously inwards or outwards via a mechanism. For this purpose, for example, each slat 30 is mounted on an axis 32 of a, for example, stationary first ring 34 (see Figure 6b), and all slats 30 are each coupled to a rotatably mounted adjusting ring 36 via a further axis 38 so that they can move together when the adjusting ring 36 rotates, while the axes 38 move in a guide slot 40 of the adjusting ring 36. The kinematics can of course also be reversed by swapping the adjusting ring and the first ring.

[0054] From Figures 6 to 9, it can be seen that the opening width of the louvre shutter is always nearly circular during its change, and the center point, i.e., the shutter axis A30, remains constant. Furthermore, the opening width becomes more circular the more louvres 30 are used. The adjusting ring 36 can be driven manually, by a spring mechanism, or by a motor, e.g., by coupling the adjusting ring 36 to a motor- or spring-driven rack segment 42 or a manually operable adjusting lever 44.

[0055] According to an advantageous embodiment, it can be provided, for example, that the lamella closure is preloaded into the closed position by a spring device, and that the lamellae 30 are moved apart by an adjusting lever for inserting the syringe plunger rod 16. Alternatively, it is also possible to preload the lamella closure into an open position by spring force and to move it into the locking position by a motor drive of the adjusting ring.

[0056] With reference to Figures 10 and 11, an advantageous embodiment of the lamella closure is shown, with which the fixation of the syringe piston rod 16 is further improved. As shown in Figure 10, the syringe piston rod 16 carries a plate at its free end, usually as a piston rod head 46, which forms an annular collar 48 on the edge. The lamellae 30 have, at least in a radially inner region on their side facing away from the main housing body 6, a beveled surface 50 which, when the syringe is inserted, can be brought into contact with the annular collar 48 of the piston rod head 46 for fixation in the drive head 10, i.e., reaches behind the annular collar 48 and presses the latter axially against a contact surface 51 in the drive head 10. In this way, the syringe piston rod 16 can be axially immovable, i.e.be positioned in the drive head 10 without play, so that the thrust acting on the syringe plunger when emptying the syringe cylinder 14 can be more accurately detected and thus better controlled. For this purpose, a pressure force sensor can be mounted behind the contact surface 51.

[0057] In order to further increase the accuracy of the axial positioning of the piston rod head 46 in the drive head 10, the lamellae 30 in the embodiment shown in Figure 10 are arranged such that they do not overlap, but lie in a common plane and are movable in this plane. Figures 11, 11a and 11b show the design of the lamellae 30 on an enlarged scale. It can be seen that the lamellae 30 support one another in the circumferential direction and have a recess in the radially inner region which forms the beveled surface 50. In the remaining region, the lamellae have the shape of plates with a thickness D30 in the mm range. The lamellae 30 can be guided in a sliding manner in the lamella closure over the plate surfaces. Metallic materials or plastics can be selected as the material for the lamellae 30.

[0058] Figure 12 schematically shows how the slats 30 of the louvre shutter can be motor-driven from a central opening position. For this purpose, the adjusting ring 36, in which the radially aligned guide slots 40 for the pivot axes 38 are formed, is equipped with a toothed segment 142, with which a gear 52 meshes. The gear 52 can be driven by a worm gear 54 of a motor 56. The motor 56 is mounted in the drive head 10 such that it is moved together with the louvre shutter.

[0059] The motor 56 can be controlled via electrical contacts 58. However, it is equally possible to drive the motor 56 via a magnetic coupling, which simplifies the positioning of the motor 56 in the drive head 10 and makes it easier to meet the requirements for tightness and hygiene. It can also be provided that the gear 52 is slidably mounted so that it can be disengaged from the gear segment 142 to allow free rotation of the adjusting ring 36.

[0060] Figures 13a, 13b, 16a, and 16b show a first variant of the centered alignment of the lamella closure LV when using syringes or syringe barrels 14 of different sizes. In this variant, the lamella closure LV is permanently mounted in the drive head 10, which is guided along an axis A58 on a support arm 58 firmly connected to the drive arm 18. The axis A58 runs perpendicular to the axis A18 of the drive arm 18 and lies in a plane E defined by the axes A14 of the syringe barrels 14 of different sizes inserted into the medical fluid pump 2. Figure 13b and Figures 16a and 16b show how the insertion of syringes of different sizes affects the displacement position of the lamella closure LV with respect to the drive arm 18 so that the center of the lamella closure LV can be aligned with the axis A14 of the syringe cylinder 14.It can be seen that the arrangement is such that the receiving area 8 of the housing main body 6 fixes the syringe cylinders 14 such that their axes A14 always lie in the plane E. In this plane E, a linear mobility or displaceability (indicated by the double arrow in Figures 16a, 16b) perpendicular to the axis A14 of the syringe cylinders 14 is provided for the lamella closure LV. To accommodate and fix the syringes shown in Figures 16a and 16b, a displacement of the lamella closure LV by the dimension V is sufficient.

[0061] Figures 14a, 14b, 15, 17a, and 17b schematically illustrate a modified form of centering the lamella closure LV. Here, the lamella closure LV is mounted for linear movement in the housing of the drive head 10, which is fixedly connected to the drive arm 18. The linear movement of the lamella closure LV is achieved by an undercut guide rail 60, into which a guide pin 62 of a stationary component of the lamella closure LV engages with positive locking. The guide rail 60 allows the lamella closure LV to move along an axis corresponding to the axis A58 shown in Figure 13a, i.e., along an axis perpendicular to the axis A18 of the drive arm 18 and lying in a plane E defined by the axes A14 of the syringe cylinders 14 of different sizes inserted into the medical fluid pump 2.To accommodate and fix the syringes shown in Figures 17a and 17b, it is again sufficient to shift the lamella closure LV by the dimension V.

[0062] Figures 18a and 18b schematically show a further variant of the design of the fixing device for the syringe plunger rods 16 of syringes of different sizes. Figure 18a is a view of a housing of the drive head 10 from the side of the syringe barrel 14, and Figure 18b is a view from the rear of the housing of the drive head 10. The housing has a drive head lower shell (not shown in more detail) and a drive head upper shell. These housing shells can be made of plastic. Arranged inside the drive head 10 is a carriage 70, which supports the lamella closure LV or is part of a stationary component of the lamella closure LV.The carriage 70 is supported via linear bearings 72, which can be formed by plain bearings or ball bearing bushes, on guide rods 74 which extend along an axis A74 which runs parallel to the plane E described above and perpendicular to the axis A14 of the syringe cylinder 14.

[0063] The drive motor 56 for controlling the slats of the slatted shutter LV is located on the rear side of the carriage 70. The drive motor drives a first gear 52-1 via the worm gear 54, which drives a second gear 52-2 on the front side of the carriage 70 via a shaft (not shown in more detail) extending through a passage 76. The second gear 52-2 meshes with a toothed segment 142 of the adjusting ring 36 of the slatted shutter LV.

[0064] This type of slide guide allows the lamella shutter LV to align itself around the syringe piston rod 16 or the annular collar 48 of the syringe piston rod 16 during closing, essentially free of frictional forces in the plane E, by moving the linear bearings 72, so that the axis A30 of the lamella shutter is aligned with the axis A14 of the syringe cylinder 14, without subjecting the syringe piston and the syringe piston rod 16 to any constraining forces. A pressure gauge can also be arranged behind the lamella shutter LV in this embodiment. Furthermore, an optionally provided spring device is designated by a double arrow 78 in Figure 18b, which can be provided to ensure a defined position of the diaphragm mechanism. It can also be used additionally to minimize external forces acting on the lamella shutter when closing the opening.

[0065] The carriage guidance is thus implemented according to a principle schematically illustrated in three views in Figures 19a to 19c, according to which a carriage 70 is accommodated in a housing with multiple linear guides and can be displaced with as little friction as possible. In the carriage guidance according to Figure 19, the carriage 70 is guided by four linear bearings 72-1 to 72-4—in contrast to the embodiment according to Figure 18.

[0066] A variant of the embodiment according to Figure 18 is schematically shown in Figure 20. Deviating from the configuration according to Figure 18, the carriage 70 carries the lamella shutter LV and the drive motor 56 on the same side, so that the additional gear 52-2 for driving the adjusting ring can be omitted.

[0067] Reference numeral 176 denotes a feedthrough for the electrical connections of the motor 56. It can be omitted if contact rails or sliding contacts are provided or if the motor 56 is driven by magnetic force coupling.

[0068] In the variant shown in Figure 21, the motor is omitted. Here, the adjusting ring 36 is driven by a manually operable gear 52, indicated by the double arrow M. Otherwise, the variant corresponds to the embodiment shown in Figure 20.

[0069] To protect the accessible components and elements of the above-described medical fluid pump, and in particular the fixing device for the syringe plunger rod 16 accommodated in the drive head 10, from contamination and to ensure easier cleaning, they can be provided with a suitable coating, for example, a liquid-repellent nanocoating. It is also advantageous to encapsulate the drive unit and control the motor magnetically.

[0070] A variant for effective shielding of the lamella mechanism is shown schematically and by way of example in Figures 22a and 22b, which is based on a lamella closure LV according to Figure 10. Figure 22a shows the lamella closure LV in the most widely opened state, while Figure 22b shows the state in which the lamellae 30 are brought radially inward into contact with the annular collar 48 of the syringe plunger rod 16. A thin-walled, elastically expandable sleeve 80 can be seen, which extends radially inward from a front wall 82 of the lamella closure to the contact surface 51 for the plate 46 of the syringe plunger rod 16 and thus shields the entire mechanism of the lamella closure from the outside. When the slats 30 are moved radially inward, the sleeve 80 deforms as shown in Figure 22b and continues to effectively shield the interior of the slatted shutter LV from external influences.

[0071] Of course, deviations from the described embodiments are possible without departing from the basic idea of ​​the invention.

[0072] The lamella closure described above can in principle be used in any type of medical fluid pump that has a housing for receiving a syringe cylinder, a fixing device for fixing a syringe piston rod, and a drive device with which a controlled relative movement in the axial direction of the syringe cylinder can be effected between the syringe cylinder and the syringe piston rod.

[0073] The described lamella closure LV can also be used to grip a syringe barrel 14 to secure it and / or to perform the relative movement between the syringe barrel 14 and the syringe plunger 16. A sensor can be provided on the lamella closure to detect the opening width of the lamella closure. This signal can then be used for syringe detection.

[0074] If a motor drive for the louvre shutter is provided, a freewheel device can be provided in the gear train to temporarily decouple manual movement of the louvres from the motor. A device can also be provided to axially movably mount the gear 52 for driving the adjusting ring 36 of the louvre shutter LV, allowing it to be brought into and out of engagement with the worm gear 54 as needed.

[0075] It is also possible to give the lamella closure in the drive head 10 mobility in two axial directions, whereby the holder for the syringe cylinders 14 in the housing main body 6 could be simplified.

[0076] The drive concepts for the LV slatted shutter can also be varied and can also use a belt drive or an eccentric drive.

[0077] The linear mobility of the slatted shutter LV in the drive head 10 can also be provided by a rail geometry formed in the drive head 10.

[0078] The described medical fluid pump 2 can also be an infusion pump.

[0079] The invention thus provides a medical fluid pump, in particular a syringe pump, comprising a housing in which a syringe barrel can be accommodated, a fixing device for fixing a syringe piston rod and / or the syringe barrel, and a drive device for effecting a controlled relative movement between the syringe barrel and the syringe piston rod in the axial direction of the syringe barrel. To improve the fixing of the syringe piston rod and / or the syringe barrel, the fixing device is formed by a plurality of lamellae that are grouped concentrically around a closure axis that can be aligned with the axis of the syringe barrel, similar to a central or lamella closure known from camera technology, and that can be moved by means of a drive device for fixing the syringe piston rod in synchronization with the change in the central free space between the lamellae.

[0080] The fixing device can be used for all types of medical fluid pumps. Additional positive effects arise when the syringe pump is designed to accommodate syringe barrels of different diameters and is equipped with a drive head that can be moved linearly along a movement axis via a tubular or rod-shaped drive arm to the housing, in which the fixing device is accommodated. To ensure that the fixing is achieved in such a way that the syringe piston rod remains free from bending stresses, the lamella closure is preferably arranged in such a way that the closure axis is guided, preferably free of frictional forces, for linear movement and perpendicular to the movement axis of the drive arm in a plane spanned by the axes of the syringe barrels of different diameters positioned in the housing.

[0081] List of reference symbols

[0082] 2 syringe pumps

[0083] 4 front flap

[0084] 5 Display

[0085] 6 Housing main body

[0086] 8 Recording area

[0087] 10 Drive head

[0088] 11 Hinge device

[0089] 12 push button

[0090] 13 spring clips

[0091] 14 Syringe cylinder A14 Axis of 14

[0092] 16 Syringe plunger rod

[0093] 18 Drive arm A18 Axis of 18 0 Shoulder section 0 Slat D30 Thickness of 30

[0094] A30 axis of 30

[0095] 32 Axis

[0096] 34 first ring

[0097] 36 Adjusting ring

[0098] 38 additional axles

[0099] 40 leadership backdrop

[0100] 42 rack segment

[0101] 142 Gear segment

[0102] 44 adjusting levers

[0103] 46 Piston rod end / plate

[0104] 48 ring bundle

[0105] 50 area

[0106] 52 gear

[0107] 54 Worm gear

[0108] 56 Engine

[0109] 58 Support arm A58 Axis of 58

[0110] 60 guide rail

[0111] 62 guide pins

[0112] 70 sleds

[0113] 72 linear bearings

[0114] 74 guide rods A74 axis of 74

[0115] 76 Implementation 176 Implementation

[0116] 78 Spring device

[0117] 80 cuff

[0118] E Level

[0119] AG large distance

[0120] AK small distance

[0121] LB linear mobility

[0122] LV louvre shutter

[0123] V Measure of displacement

Claims

Claims 1. Medical fluid pump (2), in particular a syringe pump, with a housing (6) in which a syringe cylinder (14) can be accommodated, a fixing device for fixing a syringe piston rod (16) and / or the syringe cylinder (14), and a drive device for effecting a controlled relative movement between the syringe cylinder (14) and the syringe piston rod (16) in the axial direction (A14) of the syringe cylinder (14), characterized in that the fixing device is formed by a plurality of lamellae (30) which, in the manner of a central or lamella closure (LV) known from camera technology, are grouped concentrically around a closure axis (A30) which can be aligned with the axis (A14) of the syringe cylinder (14) and which can be moved by means of a drive device (36) for fixing the syringe piston rod (16) and / or the syringe cylinder (14) synchronously with the change of the central free space between the lamellae (30). are.

2. Medical fluid pump according to claim 1, characterized in that the housing (6) is designed to accommodate syringe cylinders (14) of different sizes, and the fixing device is accommodated in a drive head (10) which is movable linearly along a movement axis (A18) via a tubular or rod-shaped drive arm (18) to the housing (6), wherein the lamella closure (LV) is arranged in such a way that the closure axis (A30) is guided so as to be movable linearly and perpendicular to the movement axis (A18) of the drive arm (18), preferably free from frictional or constraining forces, in a plane (E) which is spanned by the axes (A14) of the syringe cylinders (14) of different diameters positioned in the housing.

3. Medical fluid pump according to claim 1 or 2, characterized in that the lamellae (30) are plate-shaped.

4. Medical fluid pump according to one of claims 1 to 3, characterized in that the central or lamella closure (LV) is formed by a module.

5. Medical fluid pump according to one of claims 2 to 4, characterized in that the central or lamella closure (LV) is guided in the drive head (6) in a linearly movable manner.

6. Medical fluid pump according to one of claims 2 to 4, characterized in that the central or lamella closure (LV) is fixedly received in the drive head (10), which is movably guided and connected to the drive arm (18).

7. Medical fluid pump according to one of claims 1 to 6, characterized in that the drive device is formed by a rotatably mounted adjusting ring (36).

8. Medical fluid pump according to claim 7, characterized in that the adjusting ring is motor-driven, wherein the drive motor (56) is preferably accommodated in a drive head (10) according to claim 2.

9. Medical fluid pump according to one of claims 1 to 8, characterized in that the lamellae (30) at least in a radially inner region on their side facing away from the housing (4) each have a bevelled surface (50) which can be brought into contact with an annular collar (48) of a piston rod head (plate 46) when the syringe piston rod (16) is inserted.

10. Medical fluid pump according to one of claims 1 to 9, characterized in that the lamellae (30) lie in a common plane.

11. Medical fluid pump according to one of claims 1 to 8, characterized in that the lamellae (30) are provided with a contamination, such as a liquid-repellent coating, such as a nano-coating.

12. Medical fluid pump according to one of claims 1 to 11, characterized in that the lamellae (30) are covered by an elastically stretchable cuff (80).

13. Medical fluid pump according to one of claims 1 to 12, characterized by a sensor by means of which the opening width of the lamella closure (LV) can be detected.

14. Medical fluid pump according to one of claims 1 to 13, characterized in that the drive device is motor-driven by magnetic force coupling.

15. Medical fluid pump according to one of claims 1 to 14, characterized in that the lamella closure (LV) is designed to grip the syringe cylinder (14) in order to fix it and / or to carry out the relative movement between the syringe cylinder (14) and the syringe piston (16).

Images