PIEZO-ACTIVATED DRIVE UNIT FOR SYRINGE PUMP

Description

Technical field

[0001] The present disclosure relates to a piezoelectric drive unit for medical applications, in particular for installation in a medical syringe pump, infusion pump, dosing pump, and the like. Furthermore, an associated method for generating a slide feed of the slide of the piezoelectric drive unit is disclosed. In addition, an associated medical syringe pump with the piezoelectric drive unit and a component belonging thereto are proposed. Finally, a computer program on a data carrier for executing the method by a control unit of the piezoelectric drive unit according to the disclosure is proposed. State of the art

[0002] In medical technology, syringe pumps or infusion pumps are frequently used for the precise delivery and dosing of medical fluids such as liquid medications, drug solutions, infusions, and the like. Delivery and dosing are achieved by the controlled dispensing of the drug solution from a syringe inserted into the pump. One example of a commercially available syringe pump is the "Space plus Perfusor" from B. Braun. For precise delivery and dosing, a drive unit integrated into the syringe pump causes a linear movement of a syringe plunger. This linear movement is typically achieved through spindle drives and reduction gears to advance a piston plunger within the drive unit.However, a disadvantage of such drive systems is the high number of moving parts that must fit together, leading to increased wear points and potential sources of error. This negatively limits important aspects of these systems, particularly regarding their accuracy, durability, robustness, maintenance requirements, and manufacturing costs.

[0003] Furthermore, the use of piezoelectric elements (units) or piezo actuators (piezo actuators; in short: piezos) in the drive technology of metering or precision pumps is generally known, particularly for the design of piezoelectric actuators, but also in other applications. For example, WO 2016 / 153171 A1 relates to a dispensing pump in a process for the manufacture of electronics with a linear actuator for the direct valve metering of a liquid such as a synthetic resin, which is metered directly from a reservoir in a valve body via a nozzle by actuating a valve stem. In this process, a guide rod of the linear actuator, along which a movable element arranged on the valve stem can move, is linearly moved for direct valve metering by means of the periodic expansion and linear deformation of a piezoelectric unit.

[0004] Furthermore, JP 2006 281178 A discloses a particularly miniaturizable syringe pump for a production line in semiconductor manufacturing, capable of dispensing a tiny quantity, e.g., 0.1 microliters, of even a viscous liquid, such as an adhesive or paste, with high speed and high precision. This is achieved by the expansion and contraction of a piezoelectric element, which precisely moves a movable piston, equipped with a drive rod, by a minute amount in the conveying direction. When the drive rod moves in a first direction, a rotatably mounted ball of a coupling element is brought into pressure contact, locking it in place. This locking action prevents the coupling element from moving when the drive rod moves in a second direction.When using such a syringe pump mounted on a robot arm, its movements can be realized at high speed and with high acceleration, thus reducing the cycle time of the production line. However, insofar as the solution proposed here includes the coupling element with the ball rotatably mounted on an inclined surface, as well as sliding and spring elements, it nevertheless exhibits a disadvantageous amount of play and requires a complex interplay of individual component fits. An additional disadvantage with regard to wear is that the pressure contact of the rotatably mounted ball, which causes the locking mechanism, results in very high, point-like forces and peak loads of surface pressure (cf. Hertzian contact stress on curved surfaces) occurring in the coupling element. Furthermore, due to the small stroke or...The small dosage quantity results in a correspondingly low affordable delivery rate.

[0005] Furthermore, CN 102192135 discloses a piezoelectric pump based on the fundamental principle of a positive displacement pump, modified from a diaphragm pump known for medical applications. In this pump, the stroke of the diaphragm is generated not by a rotary motor in the usual manner, but by a piezoelectric element.

[0006] Medical syringe pumps (drives) are again known from EP 2198164 B1 and EP 3337534 A1, in which piezoelectricity is used to generate rotation or torque in an otherwise conventional unidirectional spindle drive (as described above). For example, EP 3337534 A1 discloses a drive mechanism for a portable piezoelectric (microfluidic) pump for delivering drug from a syringe, housed in a cartridge, to a patient. In the pump, piezoelectric elements, when excited, cause a linear movement of a push rod connected to the syringe, advancing the syringe and delivering the drug. The high torque generated by the piezoelectric elements is directly converted into the same torque at the lead screw, so that no torque-increasing reduction system is required.

[0007] US 4,736,131 A discloses a linear motor drive device comprising a pair of actuators, each having a first piezoelectric element, a pair of levers connected to the first piezoelectric element, and a device for amplifying the displacement caused by the first piezoelectric element. A second piezoelectric element is connected to the pair of actuators. The second piezoelectric element displaces the levers in a direction perpendicular to the direction of actuation of the levers.

[0008] US 6,104,125 A discloses a linear actuator with two spaced-apart seats connected by a central piezoelectric element. The seats are mounted in a rail frame. Each seat has a piezoelectric element and an elastic zone for engaging or disengaging from the rail frame. By alternately energizing and deactivating the central piezoelectric element, the central piezoelectric element can be alternately extended or retracted, thus moving the seats and consequently the actuator longitudinally along the rail frame. This allows for linear and precise movement of the actuator at the micrometer level.

[0009] US 5,319,257 A discloses a uniaxial drive system or microactuator capable of operation in an ultra-high vacuum environment. The mechanism comprises a flexible coupling with a through-bore and two clamping / sliding assemblies mounted at the axial ends of the coupling. The clamping / sliding assemblies are energized by voltage-driven piezoelectric elements within them to engage operatively with the shaft and coupling, causing the shaft to move through the bore along its axis of rotation.

[0010] US 2011 / 152827 A1 discloses a pump drive for drug delivery that uses a linear piezoelectric motor to advance a syringe plunger to deliver a liquid drug. The mechanism operates on a principle based on a leadscrew with a rotary axis and a ratchet.

[0011] The aforementioned state of the art therefore has a number of disadvantages and design-related limitations. In particular, medical syringe pumps with (piezoelectric) spindle drives still suffer from the problem of inherent backlash. Spindle drives require many interlocking, moving components (spindle, gears, motor, bearings, etc.). To achieve the desired or required accuracy and precision in the delivery and dosing of the medical fluid with this design, very tight dimensional tolerances and fits must be selected. These individual tolerances and fits must be coordinated with each other during the design phase and then meticulously verified and ensured through quality control after manufacturing.Furthermore, moving components are subject to wear and tear; as a result, this leads to a medium-term loss of accuracy or costly maintenance requirements.

[0012] Furthermore, the aforementioned design with a (piezoelectric) spindle drive results in a disadvantageous increase in installation space requirements, which persists despite a short stroke and a correspondingly low flow rate (or pumping capacity). Additional disadvantages arise during operation, including increased energy consumption, the generation of waste heat, and operating noise. Additionally, the low holding force of stepping and oscillating drives is a drawback. Consequently, the conventional design offers only limited suitability for use in mobile patient devices such as portable infusion pumps.

[0013] Therefore, there is a need to improve upon the aforementioned aspects and overcome the disadvantages of the prior art. One problem that the present disclosure aims to solve is to provide a quieter, more accurate, and more stable drive unit for use in medical dosing and precision pumps, particularly infusion pumps. This should reduce setup and calibration efforts. In particular, when used in a medical syringe pump, the drive unit should be suitable for providing consistent, precise dosing, especially drug delivery, over extended periods. Furthermore, it is important to present a drive unit design that exhibits reduced or even no susceptibility to wear despite high forces. Additional objectives include making the drive unit, and thus the overall pump, lighter and increasing energy efficiency.

[0014] The problem of the disclosure is solved with a piezo-actuated or piezoelectric drive unit for a medical (syringe) pump with the features of claim 1.

[0015] According to the disclosure (or according to a first-mentioned aspect of the present disclosure), a piezoelectric drive unit comprises (or has): a drive frame, a control unit, a push rod, a linear guide, a slide, and a first clamping device for the slide. The piezoelectric drive unit is configured for dispensing and / or metering medical fluids from a medical container. In particular, the piezoelectric drive unit is configured for (especially for installation in) a medical syringe pump, infusion pump, or the like, which moves in an axial longitudinal direction. The push rod on the drive frame is configured to be oscillating in the longitudinal direction by means of a longitudinal stroke device, so that, upon action of at least a first piezo actuator of the longitudinal stroke device, it is moved back and forth by its (actuated) extension and contraction.

[0016] At least one piezo actuator is connected to the control unit. That is, the control unit is configured to actuate at least one piezo actuator to oscillate by a first piezo stroke, or to expand and contract. The linear guide on the drive frame is arranged (essentially) parallel to the push rod. The carriage for conveying is movable along the linear guide in the longitudinal direction. The term "conveying" refers specifically to a conveying drive for a medical (syringe) pump using the piezoelectric drive unit as disclosed, which can be installed (especially permanently) in the (syringe) pump.

[0017] Furthermore, the control unit is configured, as disclosed, to coordinate (or control) the first clamping device of the slide. The first clamping device is configured (or controlled) to switch between a first coupling state for coupling the slide to the push rod and a first decoupling state for decoupling the slide from the push rod. The first coupling state is designed to generate a slide feed during the first coupling state in accordance with the longitudinal stroke of the push rod, which can be moved from an axial starting position. The first decoupling state is designed to release the push rod for a movement separate from the slide, in particular for a retraction movement back to the starting position.

[0018] According to the disclosure, the first clamping device is configured to have at least one second piezo actuator connected to the control unit for its actuation (i.e., activation, triggering, piezoelectrically actuated oscillation). This second piezo actuator is configured to bring about at least the first coupling state by expanding or contracting. In other words, the control unit is configured to actuate the second piezo actuator to oscillate by a second piezo stroke, or to expand and contract.

[0019] The holding mechanism of the first clamping device works by holding the (initially) advanced push rod in place. This holding mechanism is sufficient if no further tensile forces act on the slide, and is particularly sufficient to allow the slide to be moved back and forth without load. Here, the term "slide" refers to the axially movable (load-bearing) base body along the push rod.

[0020] The first clamping device is distinguished from the prior art particularly by the advantage that the first clamping force to be applied or applicable between the slide and the push rod (in a transverse direction to the longitudinal direction) can be effected directly, i.e. without (complex) force redirection.

[0021] The term piezo actuator refers to a piezoelectric component that utilizes the inverse piezoelectric effect to perform a defined mechanical movement or displacement when an electrical voltage is applied. When an electrical voltage is applied to the piezo actuator (via a control unit), the resulting displacement is a movement amplitude, a (relative) longitudinal extension, or so-called piezo stroke of the actuator, on the order of micrometers; during this movement, the actuator contracts in the transverse direction. The displacement persists as long as the electrical voltage is applied. Therefore, the movement amplitude or (relative) longitudinal extension of the piezo actuator is a reversible or oscillating displacement.

[0022] When using the piezo actuator, the amplitude of movement or the relative longitudinal extension of the piezo actuator is preferably controllable, in particular by applying an electrical voltage. In this respect, the amplitude of movement or the (relative) longitudinal extension is proportional to the electric field strength (where the field strength is defined as the quotient of voltage and electrode spacing). Specifically, the amplitude of movement or the relative longitudinal extension, i.e., an actual value or the current piezoelectric stroke, is controllable as a function of the electrical voltage. That is to say, the piezo actuator is configured to reproduce or execute the amplitude of movement or the relative longitudinal extension as a full or partial component of a nominal, theoretical, or maximum value of the (relative) displacement or longitudinal extension of the piezo actuator.

[0023] Preferably, the piezo actuator can be designed as a multilayer piezoelectric element (or piezoelectric stack). For this purpose, several thin, especially ceramic, piezoelectric elements are joined together with intervening electrodes in a series arrangement or in a sandwich construction.

[0024] The control unit for controlling the piezoelectric drive unit can be designed or equipped with a storage unit or data carrier (or machine-readable storage medium). Preferably, the storage unit or data carrier can be permanently integrated or integrated. Alternatively or cumulatively, the control unit can be electrically (or signal-wise) connected or connectable via an interface to a storage unit external to the control unit.

[0025] According to the present disclosure, several advantages and improvements arise compared to the prior art. The disclosed piezoelectric drive unit is characterized by high accuracy combined with high forces for conveying and for precise, reliable movement and guidance within the drive. In this respect, a particularly simple and fast, yet sensitive, recirculation measurement is proposed. The comprehensive use of piezoelectric technology as disclosed advantageously reduces the number of moving components compared to the prior art, resulting in reduced wear and increased robustness. Furthermore, this results in a significantly reduced installation space for the drive unit. At the same time, these considerably advantageous optimizations are achieved with at least the same, or even higher, performance and accuracy of the proposed drive unit.

[0026] A further advantage over conventional solutions is that the disclosed piezoelectric drive unit enables bidirectional drive operation. Therefore, both positive and negative slide feeds in the longitudinal direction are possible.

[0027] Furthermore, the disclosed piezoelectric drive unit operates very quietly. This represents a significant benefit for users, particularly in situations involving infusions lasting several hours and / or with portable (syringe) pumps. Moreover, compared to conventional designs, the overall piezoelectric drive implementation offers further product-related advantages, especially with regard to portable (syringe) pumps, including a small footprint, low energy consumption, and minimal heat dissipation during operation.

[0028] Preferably, alternatively, or cumulatively, at least one second piezo actuator can be configured to release the first clamping device into the first decoupling state by extending it. In particular, at least one second piezo actuator can be configured to effect the first decoupling state and / or to effect the first coupling state by contracting it.

[0029] Preferably, alternatively, or cumulatively, the at least one second piezo actuator can be configured to act on the push rod in a transverse direction by means of the first clamping device, releasing and / or clamping it. In particular, the at least one second piezo actuator can be configured to provide a compressive force acting in the first clamping device or a resulting restoring force that has a vector component acting on the push rod in the transverse direction.

[0030] Preferably, alternatively, or cumulatively, the control unit can be configured to provide a first coupling state and subsequently a first decoupling state. The first coupling state is provided to generate a slide feed corresponding to the longitudinal stroke of the pushrod, which can be moved from an axial starting position, and in particular to generate a slide feed to a longitudinally advanced (incremental, i.e., successively advanced) feed position. Subsequently, the first decoupling state is provided to release the pushrod for a movement independent of the slide. This independent movement can, in particular, involve a retraction movement of the pushrod back to its starting position while the slide remains in the (incremental) feed position.

[0031] Preferably, alternatively, or cumulatively, the piezoelectric drive unit can further comprise a guide rail and a second clamping device for the carriage. The guide rail is positioned parallel to the push rod on the drive frame. The second clamping device for the carriage can be actuated by at least one second piezo actuator and / or at least one third piezo actuator connected to the control unit. Furthermore, the second clamping device is configured to switch between a second coupling state and a second decoupling state. The second coupling state is designed to lock the carriage against unintended axial movements on the guide rail. The second decoupling state is designed to release the carriage from the guide rail, allowing it to move freely.This serves in a particularly advantageous way to secure the sled against slipping in the movable longitudinal direction.

[0032] Preferably, the guide rail can be designed with a so-called linear grinding pattern in a radial direction (or along a transverse direction or at an acute angle to a transverse direction). This serves to create additional surface resistance for further securing against slippage of the clamped surfaces relative to each other.

[0033] The second clamping device, preferably provided in addition to the first, serves to reinforce the transverse clamping of the slide, securing it against further applied loads or forces. Clamping takes place on the rib-shaped guide rail, which is a profile provided for this purpose in the drive frame, preferably an aluminum profile.

[0034] Thus, an advantageous benefit of the second clamping device lies in the additional securing of the slide against axial slippage. When the slide releases the push rod in the first decoupling state so that it can be retracted to then perform the next longitudinal stroke for the incremental slide advance (repeated cycle), the second clamping device ensures that when forces act on the slide, it remains secured against slippage. This is advantageous, for example, for securing the piezoelectric drive unit disclosed herein, or the entire drive unit system installed in a (syringe) pump, against unplanned mechanical loads. For instance, the additional securing mechanism can prove particularly beneficial in the scenario of an unintentional drop or fall of a patient with a mobile system.

[0035] Preferably, alternatively, or cumulatively, the first piezo actuator, the (optional) second, and the (optional) third piezo actuators can be designed with different technical specifications (i.e., size, type, etc.). These potentially differing technical specifications particularly concern design-relevant parameters such as the piezoelectrically actuated or nominal piezo force and / or the piezoelectrically actuated or nominal piezo stroke, and / or dimensions (length, height, width), and / or material, coating, number of layers, and the like. This allows for a particularly compact design and optimal, variable functional configuration.

[0036] Preferably, alternatively, or cumulatively, the (first / second / third) piezo stroke or the (in particular, but not limited to: unipolar) deflection or longitudinal extent, especially its nominal, theoretical, or maximum value, can be approximately 5 to 45 micrometers, more preferably approximately 8 to 16 micrometers, more preferably approximately 9 micrometers. Alternatively, or cumulatively, more preferably, the (relative to the length of the piezo actuator) deflection or the relative longitudinal extent of the (first / second / third) piezo actuator, especially its nominal, theoretical, or maximum value, can be approximately 0.1%, more preferably approximately 0.2%.

[0037] In particular, the (first / second / third) piezo actuator can have a cross-sectional area of ​​5 x 5 mm²; a length of 9 mm; an electrical capacitance of 800 nF; and / or a piezoelectric force of 850 Newtons [e.g., piezo actuator of technical type "PB 5.9" (Piezotechnics GmbH, Germany)]. Alternatively or cumulatively preferably, the piezo actuator can be at least partially encased in metal and / or formed with a protective coating, preferably polymeric or ceramic, which provides protection against high humidity.

[0038] In particular, the at least one (first / second / third) piezo actuator can refer to a plurality or multiple of the (first / second / third) piezo actuator. For example, a paired arrangement may be preferred, i.e., two (identical) first / second / third piezo actuators oscillating side by side. Accordingly, the piezoelectric forces of the first / second / third piezo actuator are advantageously increased or amplified many times over.

[0039] In particular, the second clamping device can be configured to provide the second coupling state when de-energized. In other words, the second clamping device, or the slide, is secured to the guide rail against unintended axial movement. This advantageously protects the piezoelectric drive unit against mechanical damage and / or unintended activation (or operation) due to slippage. This serves, in particular, to prevent the unintentional, and potentially harmful, administration of medication to a patient, for example, due to an accidental drop of the (syringe) pump. This is a significant safety risk, especially in the case of a portable (syringe) pump used for long-term infusion.

[0040] Preferably, alternatively or cumulatively, the control unit can be configured to provide the second decoupling state either prior to or simultaneously with the first coupling state in order to execute a slide feed of the slide according to the longitudinal stroke of the push rod movable from an axial starting position.

[0041] Preferably, alternatively or cumulatively, the control unit can be configured to provide the second coupling state directly following or simultaneously with the executed slide feed.

[0042] Preferably, alternatively, or cumulatively, at least one of the longitudinal stroke device and / or the first clamping device and / or the second clamping device can be designed as a solid-joint-mounted mechanism. In particular, the respective solid-joint-mounted mechanism can be designed to be fatigue-resistant with respect to the oscillation of at least one (associated) piezo actuator from the at least one first, second, and / or third piezo actuator. The term "solid-joint-mounted mechanism" refers to the use of solid joints, i.e., elastically deformable or deformed special areas of a (component) for motion control or in the sense of functional kinematics. This feature serves to further increase the accuracy and robustness of the drive unit as a system or arrangement. In this respect, the solid-joint-mounted mechanism is characterized by its backlash-free nature and design.Compared to the prior art described in the introduction, which uses a backlash-prone design based primarily on sliders, balls, springs, etc., the backlash-free design with solid-state joints, which is preferred here, makes the tolerance matching considerably easier. This makes the design more cost-effective. Furthermore, the preferred embodiment is characterized by a much more compact installation space and fewer parts. In particular, the preferred fatigue-resistant (or permanently elastic) design of the respective solid-state joint-supported mechanism ensures wear-free and maintenance-free operation, as well as durability without any signs of material fatigue. A mechanical load, material selection, specific geometry, and any observable (or simulated) deformation of the respective solid-state joint can be incorporated into a corresponding design within the permissible stresses in the fatigue-resistant range (according to Wöhler curves).The elastic deformation of the solid-state joint in the solid-state joint-supported mechanism results in a restoring force, similar to that of a leaf spring. This offers the advantage of eliminating the need for other restoring preload elements, such as a spring, and the associated bearing elements, such as a bushing.

[0043] Preferably, alternatively, or cumulatively, if the first clamping device is designed as a solid-body hinged mechanism, the first clamping device may include a bending spring. The bending spring is arranged in a push-rod clamping section between the push rod and the slide. Furthermore, the bending spring is rotatably mounted on the drive frame at a bending spring pivot point to form a bending spring lever arm extending towards the push-rod clamping section. Preferably, the bending spring may also be counter-supported at a contact point on the slide in a restoring manner along the extension of the bending spring lever arm. Furthermore, the bending spring is designed to deform in the transverse direction upon piezoelectrically actuated expansion of the second piezo actuator such that the push rod is released from the slide into the first decoupling state.Preferably, the bending spring can be designed to create a preload upon deformation, resulting in a bending spring restoring force in the transverse direction, such that when the second piezo actuator contracts, the slide couples back to the push rod in the first coupling state. The holding mechanism of the first clamping device functions by holding the (initially) advanced push rod in place while the solid joint returns to its original position.

[0044] Preferably, alternatively, or cumulatively, if the second clamping device is designed as a solid-body hinged mechanism, it may have a pivot-arm-like clamping lever. The clamping lever is rotatably mounted about the longitudinal axis of the linear guide in order to effect the second coupling state when the at least one second piezo actuator and / or third piezo actuator expands piezoelectrically, due to its deflection force. More preferably, the clamping lever may be designed to translate a deflection force acting on the clamping lever from the at least one second piezo actuator and / or third piezo actuator into a guide rail clamping force acting on the guide rail, amplified according to lever principles. Preferably, the clamping lever may be provided around a clamping lever pivot point that coincides with the center of the linear guide.In particular, when at least one third piezo actuator expands laterally, this causes the clamping lever to rotate around its pivot point with a corresponding clamping lever lever length. The clamping lever lever length corresponds to the distance from the clamping lever pivot point to a pressure point (during expansion) of the at least one third piezo actuator on the clamping lever.

[0045] Preferably, alternatively, or cumulatively, if the longitudinal lifting device is designed as a solid-joint mounted mechanism, the longitudinal lifting device may have a two-sided lever rocker element. The lever rocker element is pivotably mounted in its central section at an end of the drive frame located rearward of the direction of the slide feed, particularly at a rear frame plate, about a lever rocker pivot axis orthogonal to the longitudinal direction or at a lever rocker pivot point. Preferably, the fixed lever rocker pivot point can be provided in the form of a bolted connection of the solid joint to the drive frame of the drive unit. The solid joint, in particular the lever rocker element, is an element made of an elastic material, especially metal, which is always deflected or deformed elastically.Furthermore, the lever rocker element forms a short lever rocker arm and a long lever rocker arm on both sides at opposite ends, in order to effect the longitudinal stroke of the push rod when the at least one first piezo actuator is expanded by a first piezo stroke using piezoelectric actuation.

[0046] Preferably, the lever rocker element can be designed to translate the first piezo stroke of the first piezo actuator, which is applied to the short lever rocker arm, into the longitudinal stroke of the push rod arranged on the long lever rocker arm, which is enlarged according to the lever principle.

[0047] A short lever arm is configured as a segment extending from the lever pivot point to a first piezo actuator. A long lever arm is configured as a segment extending from the lever pivot point to the push rod. Around the lever pivot point, a lever with a short lever length (i.e., the short lever arm) is generated in a direction parallel to the longitudinal direction of the push rod by the first piezo stroke (e.g., approximately 0.01 mm) around the oscillating first piezo actuator. The short lever length is then multiplied around the lever pivot point by the long lever length (i.e., the long lever arm) to the push rod. Preferably, the short lever length can be 4 mm to 10 mm, and in particular approximately 7 mm. Preferably, the long lever length can be 10 mm to 25 mm, and more preferably 11 mm to 15 mm, and in particular approximately 12 mm.A lever effect of the solid-state joint is achieved according to a transmission ratio defined as the quotient of the long lever length to the short lever length. Preferably, this transmission ratio, as said quotient, can lie in the range of 1.4 to 4, more preferably from 1.5 to 2.0, and particularly from 1.7 to 1.8.

[0048] According to the aforementioned transmission ratio, a corresponding reduction in the force exerted by the first piezo actuator results, while simultaneously increasing the longitudinal stroke of the push rod. The push rod stroke performs an incremental slide advance along the longitudinal direction of the push rod. In other words, by designing the transmission ratio and / or the short and / or long lever length, a predetermined longitudinal stroke of the push rod and / or a predetermined first piezo force exerted by the first piezo actuator can be achieved. Preferably, the first piezo force, which acts axially on the push rod as a driving force for the advance, can be at least 50 Newtons, more preferably at least 100 Newtons, and particularly at least 200 Newtons.

[0049] A further (or second) aspect of the present disclosure relates to a method for generating a slide feed of the slide of a piezoelectric drive unit according to the first aspect of the present disclosure mentioned above. To avoid repetition, reference is made to the preceding disclosure relating to the first aspect with regard to essential and preferred technical features of all further aspects of the present disclosure. The method according to the disclosure can be carried out via the control unit of the piezoelectric drive unit and comprises the following steps, in particular in the form of a repeatable step sequence: An initial step relates to coupling (or coupling, clamping, temporary connecting) the slide to the push rod by means of the first clamping device of the slide into a piezoelectrically actuated first coupling state.

[0050] A further step then involves generating a slide feed, in particular to a longitudinally incremental feed position, coupled with a longitudinal stroke of the push rod from an axial starting position by means of a piezoelectrically actuated action of the longitudinal stroke device by means of at least one first piezo actuator. In particular, the slide feed can relate to a longitudinally incremental feed position.

[0051] A further step then involves decoupling (or decoupling, releasing, temporarily lifting the clamp) the slide from the push rod by means of the slide's first clamping device into a piezoelectrically actuated first decoupling state.

[0052] A further step then involves a separate movement of the push rod when the longitudinal stroke device is actuated piezoelectrically by means of at least one first piezo actuator. In particular, this separate movement can involve a retraction movement of the push rod from the longitudinally incremental advance position back to the starting position.

[0053] Preferably, alternatively or cumulatively, particularly in the case of the piezoelectric drive unit preferably provided with the second clamping device of the slide, the method (advantageously further developed beyond the basic principle) can comprise at least one of the two further optional steps that can be carried out via the control unit or both, as follows: An initial step relates to coupling (or coupling, clamping, temporarily connecting) the slide to the push rod by means of the first clamping device of the slide into a piezoelectrically actuated first coupling state.

[0054] Then, an optional step, which can be carried out by means of the second clamping device of the carriage if provided, involves switching from a second coupling state for securing the carriage against movement on the guide rail if provided, to a piezoelectrically actuated second decoupling state for releasing the carriage from the guide rail.

[0055] A further step then involves generating a slide feed, in particular to a longitudinally incremental feed position, coupled with a longitudinal stroke of the push rod from an axial starting position by means of a piezoelectrically actuated action of the longitudinal stroke device by means of at least one first piezo actuator. In particular, the slide feed can relate to a longitudinally incremental feed position.

[0056] An optional step, executable by means of the optionally provided second clamping device of the carriage, involves switching from the second decoupling state back to the piezoelectrically actuated second coupling state to secure the carriage against movement on the optionally provided guide rail, particularly in the incremental feed position. Regarding this latter step, it should be noted that the term "switching back" means that, in the case of the optionally provided second clamping device of the carriage, it makes sense to execute both associated optional steps (or neither if the second clamping device could not be used, for example, temporarily).In other words, the first optional step of switching to the second decoupling state (starting from a state in the second coupling state) is accompanied by, or functionally related to, the second optional step of (re-)switching to the piezoelectrically actuated second coupling state, especially when referring to the repeatable step sequence.

[0057] A further step then involves decoupling (or decoupling, releasing, temporarily lifting the clamp) the slide from the push rod by means of the slide's first clamping device into a piezoelectrically actuated first decoupling state.

[0058] A further step then involves a separate movement of the push rod when the longitudinal stroke device is actuated piezoelectrically by means of at least one first piezo actuator. In particular, this separate movement can involve a retraction movement of the push rod from the longitudinally incremental advance position back to the starting position.

[0059] Preferably, alternatively, or cumulatively, the method can comprise a further step executable via the control unit as follows: Controlling the oscillation of at least one piezo actuator from the at least one, second, and / or third piezo actuator. In particular, this can involve controlling the longitudinal stroke of the push rod, which is oscillatively movable on the drive frame by means of the longitudinal stroke device. More preferably, the control can be continuously variable.

[0060] A further aspect of the present disclosure relates to a medical (syringe) pump with a piezoelectric drive unit according to the first aspect of the present disclosure. Alternatively or cumulatively, the medical (syringe) pump may be designed and configured to perform the method for dispensing and / or dosing medical fluids according to the second aspect of the present disclosure mentioned above. In particular, the medical (syringe) pump may be designed as a portable infusion pump.

[0061] A further aspect of the present disclosure relates to a first clamping device and / or a second clamping device for a piezoelectric drive unit according to the first aspect of the present disclosure. In particular, the first clamping device and / or the second clamping device may be designed for use as an associated component (accessory, retrofit, or spare part). Alternatively or cumulatively, the first clamping device and / or the second clamping device may be designed for use in the method for dispensing and / or dosing medical fluids according to the second aspect of the present disclosure mentioned above.

[0062] A further aspect mentioned in the present disclosure relates to a computer program on a data carrier (or machine-readable storage medium) designed to carry out the disclosed method for dispensing and / or dosing medical liquids, wherein the method includes or executes the steps executable via the control unit, in particular the repeatable step sequence.

[0063] In summary, the use of a drive unit implemented entirely by means of piezo actuators (which are powerful, permanently precise, and wear-free), i.e., in particular as a replacement for or without the motor-driven spindle, stepping, and / or oscillating drive typically used in the drive unit, represents a key concept of the present disclosure in a syringe pump. A (piezoelectrically) axially oscillating (or longitudinally oscillating) push rod (whose longitudinal stroke is excited by the at least one first piezo actuator) pushes or pulls a slide in the desired (feed) direction. For this purpose, the push rod (or the longitudinal stroke device) as well as the first clamping device and preferably also the second clamping device are each moved by means of the associated at least one (first / second / third) piezo actuator.

[0064] Preferably, alternatively, or cumulatively, this piezoelectric actuation (or actuation, triggering, piezoelectrically actuated oscillation) can be implemented with continuously adjustable accuracy (up to the nominal maximum piezoelectric stroke of the respective (first / second / third) piezoelectric actuator), depending on the amplitude of the oscillation. Consequently, it is particularly advantageous that the accuracy of the drive (the smallest possible longitudinal stroke of the push rod or slide feed) can be continuously adjusted via the (piezoelectrically actuated) deformation of the first piezoelectric actuator.

[0065] In a particularly preferred embodiment, the different (at least one first, second, or third) piezo actuator(s), in a functional or mechanical interaction, move the slide by means of different (the first and second) clamping devices to alternately secure it on the axially oscillating push rod and on the guide rail, which is a profile fixed above the drive frame. Upon appropriate switching via the control unit, the slide is then moved or advanced (stepwise, intermittently, or cyclically) by the desired slide feed in the longitudinal direction. In other words, by means of a coordinated, temporary (or phased) clamping or coupling of the slide to the push rod and / or the guide rail, an (incremental) slide feed in the desired longitudinal direction is generated by the control unit.This results in a (drive) movement.

[0066] Preferably, alternatively, or cumulatively, the longitudinal stroke device and / or the first clamping device and / or the second clamping device can each be designed as the solid-state hinge-mounted (lever) mechanism(s). This allows, to a particularly advantageous extent, the small piezo strokes in the micrometer range of the respective associated (first / second / third) piezo actuator (even in continuous operation) to be converted into larger (useful) strokes without backlash. Furthermore, it is considered particularly advantageous that, by means of the preferred solid-state hinge-mounted (lever) mechanism(s), sufficient holding forces are generated for the movable components or the carriage, in accordance with the very high requirements for the operational reliability of such medical device drive units.

[0067] In addition, the drive unit proposed according to the disclosure can be easily designed as passively safe, i.e. locked when de-energized, in order to effectively protect a medical (syringe) pump against unintentional drug delivery in advance.

[0068] In general, as already explained above, a wide variety of technical advantages arise, which can be attributed to the permanent, high-precision nature of the piezoelectrically induced oscillation or expansion inherent in solid-state physics, even at the tiniest movement amplitudes or piezo strokes of the (first / second / third) piezo actuator. The small size of the piezo actuator also contributes to reducing the overall size of the drive unit and, consequently, the resulting (syringe) pump. With regard to a syringe pump, a slow feed rate or a piston plunger movement (a few millimeters per hour) may be preferred. In stable, clean, and quiet operation, a minimum delivery rate of, for example, 0.01 ml per hour can be achieved. Due to the previously explained energy efficiency, a longer or even extended wearing time, e.g., spanning several days, is possible in the case of a mobile (i.e., portable) device.(Pump carried / worn by a patient) can be implemented for their convenience.

[0069] The person skilled in the art understands that, based on the present disclosure, other areas of application besides a medical infusion pump are conceivable. While one focus of the conceivable applications of the present disclosure lies in the precise dosing of an infusion solution of an already diluted active ingredient or drug, pre-filled in the application form of a syringe, over a longer period, further applications and uses of the present disclosure are obvious to the person skilled in the art. This includes various tasks related to the automatic fine dosing of free-flowing liquids in production, for example in perfume blending, pharmaceutical manufacturing, etc. In particular, it is conceivable, with appropriate adjustment of the dimensions or...The technical parameters of the drive unit disclosed herein enable the precise dosing of a concentrated active ingredient or medication into a solution, particularly a stabilizing formulation and / or an infusion solution, in a diluting manner. This can be useful, for example, in an operating room setting with regard to the administration of anesthesia, whether required as a general or acute procedure, and / or for life-sustaining stabilization of a patient. In particular, the drive unit can also be optimized to perform pinpoint and / or spontaneous fine dosing in specifically desired or piezoelectrically controlled dosage volumes. Furthermore, it is conceivable to use the precise drive unit, especially by reversing the feed direction described above in the longitudinal direction of the push rod, for targeted automated sampling or blood collection in medical technology.In particular, modifications for use as a precise, wear-free drive unit of the smallest size for metering pumps or application pumps for (automated) (liquid) mixing, analysis, manufacturing, assembly are therefore obvious. Brief description of the characters

[0070] The disclosure is described in more detail below with reference to preferred embodiments and the accompanying drawings. These show: Fig. 1 a perspective view of a piezoelectric drive unit for a (not shown) medical syringe pump according to a first preferred embodiment according to the present disclosure; Fig. 2 another (to the view of Fig. 1 (rotated in space) perspective view of the piezoelectric drive unit according to the first embodiment; Fig. 3aor 3b two respective top views of the piezoelectric drive unit according to the first embodiment, illustrating a piston plunger travel of the drive unit relevant when used in the associated medical syringe pump; Figs. 4b to 4d (referring to the supervision of the Fig. 4a (marked section line BB) different representations of a longitudinal stroke device of the piezoelectric drive unit according to the first embodiment, as exemplified here as a preferred solid-body hinge-mounted mechanism: Fig. 4b a cross-sectional view in section plane BB; Fig. 4c a corresponding rear view; and Fig. 4d a perspective view of another section plane to illustrate the kinematic function of the longitudinal stroke device, which is piezoelectrically actuated by means of a first piezo actuator; Fig. 5 an enlarged section of the perspective view of the Fig. 2 (rotated in space) of the piezoelectric drive unit according to the first embodiment, focusing on the area of ​​the longitudinal stroke device for a push rod; Fig. 6 an enlarged section of the perspective view of the Fig. 1 (rotated in space) the piezoelectric drive unit according to the first embodiment, focusing on the area of ​​a second clamping device for a slide movable on the push rod, designed to secure it against movement on a guide rail; Fig. 7 a perspective view of a drive frame of the piezoelectric drive unit according to the first embodiment (isolated in the manner of an exploded view and shown in a profile-like cross-section), in particular showing the guide rail; Figs. 8a to 8c (referring to the supervision of the Fig. 4a(marked section line AA) different representations of a first clamping device and a second clamping device of the slide of the piezoelectric drive unit according to the first embodiment, as shown here by way of example as two further preferred solid-body hinge-mounted mechanisms: Fig. 8a a cross-sectional view in section plane AA (see Fig. 4a ), showing the first clamping device and the second clamping device; Fig. 8b a related detail section C from the Fig. 8a with regard to the second clamping device; and Fig. 8c a related detail section D from the Fig. 8a with regard to the third clamping device; Fig. 8d another (essentially to Fig. 8a(corresponding) cross-sectional view to illustrate the kinematic functions of the first clamping device, which is piezoelectrically actuated by means of a second piezo actuator, or of the second clamping device, which is piezoelectrically actuated by means of a third piezo actuator, of the piezoelectric drive unit according to the first embodiment; Fig. 9 a second embodiment of the piezoelectric drive unit according to the disclosure, for the schematic illustration of the temporal sequence or coordination of (work) steps executable by means of a control unit in the basic principle, i.e. when considering only a first clamping device; or for the schematic illustration of an associated method (concerning essential steps of a cycle) for dispensing and / or dosing medical liquids; Fig. 10a third embodiment of the piezoelectric drive unit according to the disclosure for the schematic illustration of the temporal sequence or coordination of (work) steps that can be carried out by means of a control unit, the case of a similar embodiment to the first embodiment (see Figures 1 to 8d ) illustrating an identical or comparable drive unit with a preferred second clamping device; or for the schematic illustration of the associated method (including optional, i.e., preferably executable, steps of a cycle); wherein otherwise comparable conditions to the second embodiment in Fig. 9 consist.

[0071] The figures are purely schematic and serve solely to aid in understanding the revelation. The same elements are designated with the same reference symbols. Description of preferred embodiments

[0072] The following are examples of embodiments of the present disclosure based on the accompanying figures.

[0073] Figures 1 to 8d relating to a piezoelectric drive unit 100 for a medical syringe pump (not shown; e.g., an infusion pump marketed under the brand name "Space Plus Perfusor" by the present applicant B. Braun) according to a first preferred embodiment according to the present disclosure. Again Figure 9 and 10 They schematically illustrate (in principle, i.e., with the patent-law character of a general disclosure) the temporal sequence or coordination of 110 (work) steps executable by means of a control unit. In particular, the extended scheme of Fig. 10 a method belonging to the first preferred embodiment.

[0074] As shown in the overall views of a piezoelectric drive unit 100 in the Figures 1 to 4dAs can be seen, this is designed with a piston plunger 90 for the axial (longitudinal) drive of a (not shown) medical syringe pump or comparable pump for dispensing and / or dosing medical fluids. The piston plunger 90 is moved in the (axial) longitudinal direction x by a (total or cumulative) piston plunger travel X (see in particular...). Figures 3a and 3b ) movable. For this purpose, the piston tappet 90 is moved in a multitude of incremental advances (cf. with reference to the Figure 9 and 10 : by means of sled feeds) proceed step by step (or in cycles, in cycles).

[0075] The piezoelectric drive unit 100 ( Figures 1 to 8dThe drive frame 70 has a drive frame 70 with a (rear) frame plate 75 at an end opposite the piston tappet 90. The drive frame 70 functions as a fixed profile or a stable outer housing. The piezoelectric drive unit 100 also has a linear guide 60. The linear guide 60, designed as a guide shaft, is clamped in the drive frame 70 in the longitudinal direction x.

[0076] Thus, a slide 20, which is movably arranged along the linear guide 60, can be moved to perform the actual feed function for conveying. A first clamping device 21 of the slide is moved in the same manner together with the slide 20.

[0077] The piezoelectric drive unit 100 further comprises a push rod 10. The push rod 10 is arranged at its end on the drive frame 70 or on the frame plate 75 via a longitudinal stroke device 11. The linear guide 60 and the push rod 10 run parallel to each other (essentially, within the limits of usual positional tolerances).

[0078] The piezoelectric drive unit 100 further comprises (at least) a first piezo actuator 1 of the longitudinal stroke device 11, a second piezo actuator 2 of the first clamping device 21, and a third piezo actuator 3 of a second (optional) clamping device 32. Specifically, the first piezo actuator 1 (in particular...) consists of... Fig. 4c ), the second piezo actuator 2 and the third piezo actuator 3 (especially Fig. 6 ) each in pairs consisting of two such next to each other, i.e. in the manner of a first / second / third double piezo actuator.

[0079] The respective first / second / third piezo actuators 1, 2, 3 are connected to a control unit 110 (indicated or drawn as a symbol box with a dashed outline) for piezoelectrically actuated expansion and contraction by a first / second / third piezo stroke. The control is effected by the control unit 110 in the respective figures via the control connections shown as dashed lines or arrows (see figure). Figures 1, 1 , 3a / b, 4a / d, 8a / d; 9 and 10). Preferably, the first / second / third piezo stroke is continuously adjustable (depending on a respective applied control voltage).

[0080] The push rod 10 is arranged to oscillate in the longitudinal direction x by a longitudinal stroke h by means of the longitudinal stroke device 11, or is (longitudinally) oscillated or moved back and forth. At least one first piezo actuator 1 of the longitudinal stroke device 11 acts on the push rod 10. Thus, the carriage 20 is moved along the linear guide 60 due to the first piezo force implemented by the longitudinal stroke device 11, by pushing (or pulling back) the carriage 20 from the push rod 10.

[0081] Especially the Figures 4b to 4d (referring to the supervision of the Fig. 4aAs can be seen from the marked section line BB), the longitudinal lifting device 11 is designed with a two-sided lever rocker element 15 (as a preferred solid-joint mounted mechanism). The lever rocker element 15 is pivotably mounted in its central lever rocker section 16 on the frame plate 75 about a lever rocker pivot axis Y orthogonal to the longitudinal direction x. At the opposite ends of the (two-sided) lever rocker element 15, a short lever rocker arm f and a long lever rocker arm e are formed.

[0082] When the at least one first piezo actuator 1 is expanded by a first piezo stroke via piezoelectric actuation, the longitudinal stroke h of the push rod 10 is effected (cf. Figure 9 and 10 ). Fig. 4dThe diagram uses arrows to illustrate the kinematic function and the lever-like transmission. For example, the maximum delivery force required for a syringe pump or standard infusion syringes can be approximately 100 Newtons. The push rod 10 is designed to provide this delivery force. For example, the piezo actuators selected for (at least one) the first piezo actuator are specified by the manufacturer for a maximum piezo force of 850 Newtons and a maximum piezo stroke of 0.009 mm. The lever rocker element 15 reduces the force (piezo force converted to push rod force) while simultaneously increasing the stroke (piezo stroke converted to longitudinal stroke as the push rod working stroke). Here, according to the lever principle, the two lever lengths of the long lever rocker arm e and the short lever rocker arm f come into play. Figures 4a to 4d An example of a force reduction of 1 : 2 is shown.

[0083] The first clamping device 21 of the slide 20 is controlled by the control unit 110 via the second piezo actuator 2. After clamping has occurred, the slide 20 can be moved along with the (moving) push rod 10 in a (temporary) first coupling state. Accordingly (see Figure 9 and 10 The slide is advanced according to the longitudinal stroke of the push rod. To allow the push rod 10 to perform a separate retraction movement back to its starting position, independent of the slide 20, without retracting the slide 20 or unintentionally reversing the desired slide advance, the first clamping device 21 is returned to a first decoupling state.

[0084] Especially the Figures 8a (referring to the supervision of the Fig. 4aThe first clamping device 21, as shown in the marked section line AA), 8c, 8d, is designed with a bending spring 25 (as a preferred solid-body hinge-mounted mechanism). The bending spring 25 is arranged in a push-rod clamping section 26 between the push rod 10 and the slide 20. Furthermore, the bending spring 25 is rotatably mounted on the drive frame 70 at a bending spring pivot point Q to form a bending spring lever arm d extending towards the push-rod clamping section 26. The bending spring 25 is also supported against the slide 20 at a contact point R in the extension of the bending spring lever arm d in a restoring manner. When the second piezo actuator 2 is extended in the transverse direction (see Figure 8c, 8d), the bending spring 25 is released. Fig. 1: y, z) the bending spring is deformed such that the push rod 10 is decoupled or released from the slide 20. The deformation also causes a preload with a bending spring restoring force in the transverse direction (reaction to F2, as indicated by the arrows), so that when the second piezo actuator 2 contracts, the slide 20 couples back to the push rod 10 in the first coupling state or is clamped.

[0085] The piezoelectric drive unit 100 according to the preferred first embodiment further comprises a guide rail 30 and a second clamping device 32 of the carriage 20. The guide rail 30 is provided in the longitudinal direction x, i.e., parallel to the push rod 10, on the drive frame 70 (in particular, Fig. 7 ). The second clamping device 32 of the slide 20, as in particular the Figure 6 , 8a, 8bAs can be seen in section 8d, the third piezo (dual) actuator 3 is used to switch between a second coupling state and a second decoupling state. During the temporary period of the second coupling state (which also occurs when there is no current), the carriage 20 is secured or blocked against unintended axial movements on the guide rail 30. During the temporary period of the second decoupling state, the carriage 20 is released from the guide rail, or the previously existing blockage is lifted, allowing it to move freely in the longitudinal direction.

[0086] For the design of the second clamping device 32, it is preferable to consider not the conveying force, but rather the potential force acting upon it during a fall. In such a scenario, the carriage 20 must not break free. For example, assuming the following: a fall height of approximately 1 m, a syringe pump weighing approximately 2 kg, and an impact duration of 10 ms, the force acting upon impact can be estimated at approximately 886 Newtons using the force-impulse equation. At least this clamping force, and in particular a force greater than or equal to 1,000 Newtons, must be applied by the first and / or second clamping device(s) 21, 32 (alone or together).

[0087] Since a minimum value for a (second and / or third) piezo stroke must also be realized (due to elasticities in the respective clamping mechanism) to ensure safe opening and closing, two (second or third) piezo actuators are used here, and their piezo force is connected in parallel as a (second or third) double piezo actuator (in Figures 8a, 8c , 8d (not recognizable due to the views in a cross-section).

[0088] Especially the Figure 6 , 8a (referring to the supervision of the Fig. 4a The second clamping device 32, as shown in the marked section line AA), 8b, 8d, is designed with a pivot-arm-like clamping lever 35 (as a preferred solid-body hinge-mounted mechanism). The clamping lever 35 rotates about the longitudinal axis M (in particular, Fig. 8dThe linear guide 60 is rotatably mounted. The piezoelectrically actuated expansion of the third piezo actuator 3 is caused by its deflection force, or third piezo force, acting on the clamping lever 35 (see the arrow at the top left in the diagram). Fig. 8d (indicated deflection in the direction of rotation) the second coupling state. The third piezoelectric force is converted into a guide rail clamping force, amplified according to the lever principle, which acts on the guide rail 30.

[0089] As can be seen in particular from the Figure 6 Understandably, the slide 20 is arranged in an outer sheet metal body. A slide pressure element 29 is designed as a (top in Fig. 6 A U-shaped wire spring, secured by Torx screws, is arranged. The slide pressure element 29 ensures that the sheet metal body is always free of play relative to the transversely oscillating third piezoelectrics 3 (expanding to the upper right). Fig. 6) is connected. When the pair of third piezoelectric elements 3 expands, the slide pressure element 29 is biased to exert downward counterforces. In this respect, the (U-shaped) slide pressure element 29, in its tendency to align itself in a straight line, exerts a restoring pressure force against the slide 20, or rather, a counterforce to the third piezoelectric force resulting from the expansion of the third piezoelectric elements 3. In other words, the spring force of the (U-shaped) slide pressure element 29 acts downwards, or against the sheet metal body, thereby generating the guide rail clamping force that secures the slide 20.

[0090] Fig. 9 or Fig. 10Figure 1 shows a second and a third embodiment of the piezoelectric drive unit according to the disclosure, as well as the associated method. Here, the temporal sequence and coordination of (work process) steps executable by means of a control unit 110 (indicated by a dashed line) in a (repeatable) basic cycle S1 to S4 and in an extended cycle S101 to S106 are schematically (or in principle) illustrated. The control unit 110 is configured to actuate (or trigger) at least one first, second, and, if applicable, third piezo actuator (via the control connections indicated by dashed lines) for piezoelectric oscillation.

[0091] In short, the basic cycle S1 to S4 involves alternating coordination, in which either the carriage moves or does not move, and the push rod 10 is either clamped by the carriage or not clamped.

[0092] Insofar as the in Fig. 10 The sequence shown corresponds to the cycle extended by the optional steps S102 and S104. Fig. 10 especially with the first embodiment (see Figures 1 to 8d ) the piezoelectric drive unit according to the disclosure, which additionally has the preferably provided second clamping device (locking on the guide rail 30). For the sake of clarity, the Figure 9 and 10 For simplicity, not including the longitudinal stroke device 11, the first clamping device 21 and, if applicable, the second clamping device 32 (reference numerals referring to the structural device aspects emphasizing Figures 1 to 8d) as such, but only one of the associated first piezo actuator 1, one of the associated second piezo actuator 2, and possibly one of the associated third piezo actuator 3 are shown. Therefore, the (relative or incremental) position (on the horizontally drawn travel axis) of the (also not shown) carriage (20) can be determined from the (relative or incremental) position of the second piezo actuator 2 (possibly together with that of the third piezo actuator 3): Initially (or at the start of each new cycle of the repeatable cycle S1 to S4; S101 to S106), a step S1, S101 of coupling / clamping of the carriage to the push rod 30 takes place. The carriage is clamped to the push rod 30 by means of piezoelectrically actuated expansion of the second piezo actuator 2 (see vertical arrows in Fig. 9 ). This corresponds to the (temporary) first coupling state of the first clamping device of the slide.

[0093] In short, in step S1, S101 the push rod10 is gripped by the carriage (clamped by means of the second piezo actuator 2).

[0094] Then, optionally (only Fig. 10 ) a step S102 of switching from a second coupling state (locking the carriage against the guide rail 30) to a (temporary) second decoupling state (unlocking the carriage from the guide rail 30). For this purpose, the third piezo actuator 3 (of the second clamping device of the carriage) is piezoelectrically actuated to expand, so that the previously existing clamping is released, thus enabling movement.

[0095] In short, in (optional) step S102 the clamping or running restriction of the carriage on the guide rail 30 is lifted or released.

[0096] Then a further step S2, S103 (generating) a slide feed s of the slide takes place, which is triggered or caused by a longitudinal stroke h of the push rod (see in Fig. 9 / 10 (the horizontal arrow and the finely dashed vertical line on the left of the image). The first piezo actuator 1 of the longitudinal stroke device extends from an axial starting position. It should be noted that in the schematic representation of the Figure 9 , 10 the first piezo stroke coincides with the longitudinal stroke h. That is, a lever implementation, which may be preferably provided (cf. Figures 4a to 4d ) is neglected here; the same applies to the piezo actuators 2, 3.

[0097] In short, in step S2, S103 the push rod 10 performs a longitudinal stroke h by being advanced by a first piezo stroke of the first piezo 1, thereby taking the pre-clamped slide with it.

[0098] Then, optionally (only Fig. 10) a step S104 of a (re-)change from the second decoupling state (release of the carriage from the guide rail 30) to the (temporary) second coupling state (locking of the carriage to the guide rail 30). For this purpose, the third piezo actuator 3 (of the second clamping device of the carriage) is piezoelectrically actuated to retract. Due to the coupling / clamping of the carriage to the guide rail 30, the carriage is secured against slippage.

[0099] In short, in (optional) step S104 the carriage is clamped or secured or its movement is restricted on the guide rail 30.

[0100] In a subsequent step S3, S105, the slide is decoupled from the push rod 30. For this purpose, the slide is released from the push rod 30 by means of piezoelectrically actuated contraction of the second piezo actuator 2 (see vertical arrows in Fig. 9). This corresponds to the first (temporary) decoupling state of the first clamping device of the slide.

[0101] In short, in step S3, S105 the slide releases its clamping to the push rod 30.

[0102] Subsequently, in step S4, S106, the push rod 10, separated from the slide 10, is moved or pulled back to its starting position (see in Fig. 9 / 10 (the horizontal arrow and the fine dashed vertical line on the left of the image). The first piezo actuator 1 of the longitudinal stroke device then retracts to its axial starting position.

[0103] In short, in steps S4 and S106, the push rod 10 is retracted back to its starting position, while the carriage remains at a new (incremental) feed position. Compare this to the offset of the carriage according to that of the second piezo actuator 2 at the beginning of the new cycle during the repeated step S1 or S101 (bottom of the image) compared to its position at the beginning of the first cycle (top of the image).

[0104] Through (multiple) repetitions of the cycle, the incremental slide feeds s add up or accumulate. This results in the total piston tappet travel X (with reference to the Figures 3a / 3b ). List of reference symbols

[0105] 1. First piezo actuator 2. Second piezo actuator 3. Third piezo actuator 10. Push rod 11. Longitudinal stroke device 15. Lever rocker element 16. Lever rocker center section 21. First clamping device 20. Slide 25. Bending spring 29. Slide pressure element 30. Guide rail 32. Second clamping device 35. Clamping lever 60. Linear guide 70. Drive frame 75. Frame plate 90. Piston plunger 100. Drive unit 110. Control unit a. Lever arm of the third piezo (second clamping device) b. Lever arm of the clamping lever (second clamping device) c. Lever arm of the second piezo (first clamping device) d. Lever arm of the bending spring (first clamping device) e. Long lever rocker arm (longitudinal stroke device) f. Short lever rocker arm (longitudinal stroke device) h. Longitudinal stroke sSlide feed xLongitudinal direction yWidth direction (transverse direction) zHeight direction (transverse direction) F2Bounce spring deformation force MLlongitudinal axis (linear guide) RContact point (bending spring) QPivot point (bending spring) XPiston tappet travel YLever rocker pivot axis S1 - S600 process steps

Claims

1. A piezoelectric drive unit (100) for dispensing and / or dosing of medical liquids from a medical container, especially for a medical-technical syringe pump, infusion pump or the like travelling in an axial longitudinal direction (x), comprising: - a drive frame (70), - a control unit (110), - a push rod (10) which is configured at the drive frame (70) to be movable in an oscillating manner about a longitudinal stroke (h) in the longitudinal direction (x) by means of a longitudinal stroke device (11) in order to be moved back and forth with acting of at least one first piezo actuator (1) of the longitudinal stroke device (11) connected to the control unit (110) by expansion and contraction thereof, - a linear guide (60) arranged at the drive frame (70) parallel to the push rod (10), - a carriage (20) movable along the linear guide (60) for conveying in the longitudinal direction (x), and - a first clamping device (21) of the carriage (20), coordinated by the control unit (110), which is configured to switch between a first coupling state for coupling of the carriage (20) to the push rod (10) and a first decoupling state for decoupling of the carriage (20) from the push rod (10), wherein the first coupling state is provided to meanwhile generate a carriage advance (s) of the carriage (20) according to the longitudinal stroke (h) of the push rod movable from an axial starting position to an advance position of the carriage (20) incremental in longitudinal direction (x), the first decoupling state is provided to release the push rod (10) for a motion separate from the carriage (20) for its retracting motion back to the starting position while remaining of the carriage (20) at the incremental advance position, and the first clamping device (21) comprises at least one second piezo actuator (2) connected, for its actuating, to the control unit (110), whereby the at least one second piezo actuator (2) is configured to cause, by expansion or contraction thereof, at least the first coupling state.

2. The piezoelectric drive unit (100) according to claim 1, characterized in that the at least one second piezo actuator (2) is configured to release, by expansion thereof, the first clamping device (21) into the first decoupling state, especially to cause the first decoupling state and / or to cause, by contraction thereof, the first coupling state.

3. The piezoelectric drive unit (100) according to claim 1 or 2, characterized in that the at least one second piezo actuator (2) is configured to act, by expansion thereof, by means of the first clamping device (21) in a cross direction (y, z) in a releasing and / or clamping manner on the push rod (10), especially to provide a compressive force (F2) acting in the first clamping device (2) or a resulting restoring force having a vector component acting in the cross direction (y, z) on the push rod (10).

4. The piezoelectric drive unit (100) according to any of the preceding claims, characterized in that the piezoelectric drive unit (100) further comprises: - a guide rail (30) provided parallel to the push rod (10) at the drive frame (70); and - a second clamping device (32) of the carriage (20), which is actuatable by means of the at least one second piezo actuator (2) and / or of at least one third piezo actuator (3) connected to the control unit (110), whereby the second clamping device (32) is configured to switch between a second coupling state, especially provided without current, for run-inhibiting securing of the carriage (20) to the guide rail (30) against unintended axial movements and a second decoupling state for run-free de-securing of the carriage (20) from the guide rail (30).

5. The piezoelectric drive unit (100) according to the directly preceding claim, characterized in that the control unit (110) is configured: to provide the second decoupling state, respectively, temporally precedingly or simultaneously to the first coupling state in order to perform a carriage advance (s) of the carriage (20) according to the longitudinal stroke (h) of the push rod (10) movable from an axial starting position; and / or to provide the second coupling state, respectively, temporally directly subsequently or simultaneously to the performed carriage advance (s).

6. The piezoelectric drive unit (100) according to any of the preceding claims, characterized in that the longitudinal stroke device (11) and / or the first clamping device (21) and / or the second clamping device (32) is or, respectively, are formed as a respective solid body joint-supported mechanism, especially is or, respectively, are formed durable with respect to the oscillation of at least one piezo actuator from the at least one first, second and / or third piezo actuator (1, 2, 3).

7. The piezoelectric drive unit (100) according to the directly preceding claim, characterized in that in the case of the first clamping device (21) formed as a solid body joint-supported mechanism, it comprises a bending spring (25) which is arranged in a push rod clamping section (26) between the push rod (10) and the carriage (20), whereby the bending spring (25): - is rotatably supported on the drive frame (70) in a bending spring pivot point (Q) to form a bending spring lever arm (d) extending toward the push rod clamping section (26); - preferably is further restoringly counter-supported on the carriage (20) in an abutment point (R) in extension of the bending spring lever arm (d); and - is formed to deform with piezoelectrically actuated expansion of the second piezo actuator (2) in the cross direction (y, z) such that the push rod (10) is released from the carriage (20) into the first decoupling state; further preferably - is formed to cause, with deformation thereof, a preload with a bending spring restoring force (- F2) resulting in the cross direction (y, z), so that, with contraction of the second piezo actuator (2), the carriage (20) couples back to the push rod (10) into the first coupling state.

8. The piezoelectric drive unit (100) according to claim 6 or 7, characterized in that in the case of the second clamping device (32) formed as a solid body joint-supported mechanism, it comprises a pivot arm-like clamping lever (35), whereby the clamping lever (35): - is rotatably supported about the longitudinal axis (M) of the linear guide (60) in order to cause the second coupling state with piezoelectrically actuated expansion of the at least one second piezo actuator (2) and / or third piezo actuator (3) by its deflection force; further preferably - is formed to translate a deflection force of the at least one second piezo actuator (2) and / or third piezo actuator (3) acting on the clamping lever (35) into a guide rail clamping force, thereto amplified according to the lever law, applied to the guide rail (30).

9. The piezoelectric drive unit (100) according to any of claims 6 to 8, characterized in that in the case of the longitudinal stroke device (11) formed as a solid body joint-supported mechanism, it comprises a double-sided lever rocker element (15), whereby the lever rocker element (15): - in its central lever rocker midsection (16) at a rear end of the drive frame (70) with respect to a direction of the carriage advance (s), especially at a rear frame plate (75), is pivotally supported about a lever rocker rotation axis (Y) orthogonal to the longitudinal direction (x) and for this purpose forms on both sides at the opposite ends a short lever rocker arm (f) and a long lever rocker arm (e), respectively, in order to cause the longitudinal stroke (h) of the push rod (10) with piezoelectrically actuated expansion of the at least one first piezo actuator (1) by a first piezo stroke; further preferably - is formed to translate the first piezo stroke of the first piezo actuator (1) applied to the short lever rocker arm (f) into the longitudinal stroke (h) of the push rod (10) arranged on the long lever rocker arm (e), which is enlarged according to the lever law.

10. A method for generating a carriage advance of the carriage of a piezoelectric drive unit (100) according to any of the preceding claims comprising the steps subsequently executable via the control unit (110), especially in the manner of a repeatable step sequence (S1-S4; S101-S106): - coupling (S1, S101) of the carriage (20) to the push rod (10) by means of the first clamping device (21) of the carriage (20) into a piezoelectrically actuated first coupling state; - preferably optional switching (S102) by means of the, if applicable, provided second clamping device (32) of the carriage (20) from a second coupling state for run-inhibiting securing of the carriage (20) at the, if applicable, provided guide rail (30) into a piezoelectrically actuated second decoupling state for run-free de-securing of the carriage (20) from the guide rail (30); - generating (S2, S103) of a carriage advance of the carriage (20) to an advance position incremental in longitudinal direction (x), coupled with a longitudinal stroke (h) of the push rod (10) from an axial starting position with acting of the longitudinal stroke device (11) piezoelectrically actuated by means of the at least one first piezo actuator (1); - preferably optional switching (S104) by means of the, if applicable, provided second clamping device (32) of the carriage (20) from the second decoupling state back into the piezoelectrically actuated second coupling state for run-inhibiting securing of the carriage (20) to the, if applicable, provided guide rail (30), especially on the incremental advance position; - decoupling (S3, S105) of the carriage (20) from the push rod (10) by means of the first clamping device (21) of the carriage (20) into a piezoelectrically actuated first decoupling state; - separate motion (S4, S106) of the push rod (10) as a retracting motion of the push rod (10) from the advance position incremental in the longitudinal direction (x) back to the starting position, with acting of the longitudinal stroke device (11) piezoelectrically actuated by means of the at least one first piezo actuator (1).

11. The method according to the directly preceding claim, characterized in that further step is executable via the control unit (110): - controlling, preferably stepless controlling, of the oscillation of at least one piezo actuator (1, 2, 3) from the at least one, second and / or third piezo actuator, especially controlling of the longitudinal stroke (h) of the push rod (10) movable in an oscillating manner at the drive frame (70) by means of the longitudinal stroke device (11).

12. A medical-technical syringe pump with a piezoelectric drive unit (100) according to any of the preceding claims directed to the drive unit (100), in particular a fusion pump portable by a user.

13. A computer program on a data medium, configured for performing the method according to any of claims 10 or 11, whereby the method comprises the steps executable via the control unit (110), especially the repeatable step sequence (S1-S4; S101-S106).