Metering assembly for implantable infusion device and implantable infusion device having such metering assembly

Abstract

The present invention relates to an implantable infusion device for delivering infusion fluid to a patient, and a metering assembly for such an implantable infusion device. The infusion device comprises a pressurized infusion fluid reservoir, an infusion fluid dispensing member and the metering assembly. The metering assembly includes an inlet valve, an outlet valve, and an infusion fluid accumulator having an accumulator volume in line with the valves. The two valves are both normally closed. An inlet valve controls the inflow of infusion fluid from the infusion fluid reservoir into the accumulator volume. An outlet valve controls the outflow of infusion fluid from the accumulator volume into the infusion fluid dispensing member. The metering assembly also includes an actuator device for actuating the valve. The actuator arrangement includes an actuator that alternately actuates the two valves so as to avoid simultaneous opening of the two valves.

Description

Technical Field

[0001] The invention relates to a metering assembly according to the preamble of claim 1 and an implantable infusion device according to the preamble of claim 12 . Background Art

[0002] U.S. Patent No. 5,049,141 discloses an implantable infusion device having the features of the preamble of claim 12. The prior art implantable infusion device includes a metering assembly having the features of the preamble of claim 1. The prior art implantable infusion device is intended for delivering an infusate (i.e., a medical fluid or fluid medication) to a patient and comprises a pressurized infusate reservoir, an infusate dispensing member, and the metering assembly. The infusate reservoir is filled with the infusate and pressurized at a pressure higher than the pressure inside the patient's body. The infusate dispensing member of the prior art device is in the form of a catheter and is configured to dispense the infusate from the infusate reservoir to a site inside the patient's body. The metering assembly is configured to control the amount of infusate to be infused per unit time, i.e., the medication dose. To this end, the prior art metering assembly includes an infusate reservoir having an accumulator volume and a pair of normally closed valves, i.e., an inlet valve and an outlet valve. The inlet valve controls the inlet of the infusate from the reservoir into the accumulator volume. The outlet valve controls the outlet of infusate from the accumulator volume to the infusate dispensing member. In a first state, the inlet valve is open and the outlet valve is closed, thereby allowing infusate flow from the pressurized infusate reservoir into the accumulator volume while simultaneously blocking infusate flow from the accumulator volume through the dispensing member. In a second state, the inlet valve is closed and the outlet valve is open, thereby allowing infusate flow from the accumulator volume through the dispensing member while simultaneously blocking infusate flow from the pressurized infusate reservoir into the accumulator volume. The accumulator volume has a pressure between the pressure of the pressurized infusate reservoir and the pressure inside the patient's body. Thus, in the second state, infusate accumulated within the accumulator volume is "pumped" from the accumulator volume into the infusate dispensing member and, thus, into the patient's body. Cycling between the first and second states allows control of the infused medication dose, wherein increasing the cycling rate increases the infused volume per unit time, and thus, the medication dose. The metering assembly of the prior art includes an actuator device, which is configured to actuate the inlet valve and the outlet valve between the first state and the second state. The actuator device of the metering assembly of the prior art includes two separate actuators for controlling the opening and closing cycles of the inlet valve and the outlet valve. The separate actuators are in the form of electronically controlled solenoids, with the first solenoid actuating the inlet valve and the second solenoid actuating the outlet valve. There is a potential risk that magnetic field effects (e.g., during magnetic resonance imaging (MRI)) may cause the solenoids to malfunction, resulting in the inadvertent opening of both the inlet valve and the outlet valve, thereby leading to an uncontrolled overdose of the drug. Summary of the Invention

[0003] It is an object of the present invention to provide a metering assembly and an implantable infusion device as mentioned at the outset which have increased safety and at the same time are of simple and robust design.

[0004] In a metering assembly, this objective is addressed by providing an actuator device movable between a first position and a second position for alternately actuating an inlet valve or an outlet valve between the first and second states. In the first position, the actuator mechanically actuates the inlet valve and does not actuate the outlet valve, and in the second position, the actuator mechanically actuates the outlet valve and does not actuate the inlet valve. Because both the inlet and outlet valves are alternately mechanically actuated by the same actuator, simultaneous actuation of both valves is impossible. Consequently, simultaneous opening of the inlet and outlet valves and the resulting uncontrolled delivery of infusate are impossible. This improves safety. Furthermore, using the same actuator to actuate both valves results in a simple and robust design, allowing for easy and inexpensive manufacturing. In various embodiments, the actuator is movable between the first and second positions in different ways. In one embodiment, the actuator moves linearly and / or translationally. In another embodiment, the actuator moves rotationally. In yet another embodiment, the actuator moves pivotally. Of course, a combination of linear, rotational, and / or pivotal motions of the actuator is also possible and contemplated. Movement between the first and second positions can be the result of rigid-body motion of the actuator, elastic deformation of at least a portion of the actuator, or a combination of both. Both valves are normally closed, i.e., if and when not actuated by the actuator, they are in a closed state that blocks the flow of the infusate. Thus, the first position of the actuator controls the first state, and the second position of the actuator controls the second state. In one embodiment, the inlet valve and the outlet valve each include a biasing member configured to bias the respective valve into its closed position. In another embodiment, each valve includes a closing mechanism configured to maintain the respective valve closed if and when not actuated. In different embodiments, the actuator actuates the valves in different ways. In one embodiment, the actuator is configured to open the valves by a pushing motion and / or a thrust. In another embodiment, the actuator is configured to open the valves by a pulling motion and / or a pulling force. In yet another embodiment, the actuator is configured to open the valves by a rotational motion and / or a torque. Of course, combinations of these are possible and contemplated. The mechanical action of the actuator on the inlet valve and the outlet valve may be direct or indirect. In one embodiment, a portion of the actuator alternately directly contacts a portion of the inlet valve or a portion of the outlet valve, said contact transmitting the force and / or motion of the actuator to the respective valve in order to open it. In another embodiment, said alternating contact is indirect, the actuator acting on a transfer member which in turn (directly) acts on the respective valve. The pressurized infusate reservoir and the infusate dispensing member do not form part of the metering assembly, but rather form part of the implantable infusion device. The infusate reservoir is configured to contain and pressurize the infusate by known techniques, for example by means of pressure induced by a two-phase fluid.The technical details of the pressurized infusate reservoir are not essential to the present invention and are therefore omitted. In a preferred embodiment, the infusate dispensing member is a catheter. However, the technical details of the infusate dispensing member are not essential to the present invention and are therefore omitted. This also applies mutatis mutandis with respect to an infusate reservoir having an accumulator volume. In a preferred embodiment, the accumulator volume is formed by means of a diaphragm arranged in an accumulator chamber of the infusate reservoir, wherein the diaphragm is deflectable by means of an influx of infusate from the pressurized infusate reservoir while the valve is in the first state. The pressure on the rear side of the diaphragm may be the intermediate pressure that causes the described "pumping" action of the infusate reservoir. However, other infusate reservoir designs are possible and envisaged.

[0005] In one embodiment, an actuator includes an actuator member that alternately acts on an inlet valve or an outlet valve; and a force-generating member operatively coupled to the actuator member and configured to generate a force and / or motion for moving the actuator member between a first position and a second position. In one embodiment, the actuator member is a lever arm that is pivotally movable and / or flexibly bendable between the first position and the second position. In another embodiment, the actuator member is a push rod or pull rod that is linearly movable between the first position and the second position. In yet another embodiment, the actuator member is a cam member that is rotationally movable between the first position and the second position. The force-generating member is configured to generate a force and / or motion for moving the actuator member between the first position and the second position. In one embodiment, the force-generating member is configured to move the actuator member from the first position to the second position, while moving the actuator member from the second position to the first position by means of the force-generating member is not possible. In another embodiment, the force-generating member is configured to move the actuator member from the second position to the first position, while reversing the positioning by means of the force-generating member is not possible. In these cases, the actuator preferably includes a biasing member operatively coupled to the actuator member, the biasing member biasing the actuator member into the inactive actuation position. In yet another embodiment, the force generating member is configured to move the actuator member between two positions, which allows the biasing member to be omitted. In a preferred embodiment, the force generating member is a piezoelectric element. In other embodiments, the force generating member relies on other physical operating principles, such as hydraulics, pneumatics, or magnetism, to generate the force and / or motion.

[0006] In one embodiment, the actuator includes a biasing member that is operatively coupled to the actuator member and biases the actuator member against the force and / or movement of the force-generating member. This enables the use of a unidirectional force-generating member that is configured to move the actuator member from a first position to a second position or vice versa, but not to alternate between the two positions. Consequently, further design simplification and cost reduction can be achieved. In one embodiment, the biasing member is a spring element, preferably in the form of a coil spring. In another embodiment, the biasing member is an elastomeric element or the like.

[0007] In one embodiment, the actuator member is a lever arm movable between a first position and a second position by means of a force-generating member, the lever arm amplifying the movement of the force-generating member into an amplified actuating movement. The lever arm leverages the movement of the force-generating member. This allows the use of a force-generating member with a relatively small range of motion / displacement, which would not be sufficient to actuate the valve without the leverage effect. The use of a force-generating member with a small displacement / range of motion can lead to further simplified design and reduced costs. The lever arm has a positive mechanical advantage with respect to the movement of the force-generating member. Preferably, the mechanical advantage is in the range of between 1:5 and 1:60, preferably between 1:10 and 1:30, and more preferably at least about 1:20. Therefore, due to the basic mechanical principles involved, the mechanical advantage of the force of the force-generating member is negative.

[0008] In one embodiment, the lever arm is hinged at a pivot and is pivotally movable between a first position and a second position. The pivot is, for example, in the form of a pin, a fulcrum, or the like. In this embodiment, the lever arm is at least substantially rigid, and the movement of the lever arm between the first position and the second position is therefore a rigid body motion. This embodiment allows for a further simplified and more robust design.

[0009] In one embodiment, the lever arm is fixedly mounted and flexibly bendable between a first position and a second position. In this embodiment, at least a portion of the lever arm is resilient and / or flexible to allow for flexible bending movement between the first position and the second position. This can be achieved by selecting an appropriate resilient material and / or geometric properties of the lever arm. Since no pivot and / or fulcrum is required, this embodiment allows for a very simple and very robust design.

[0010] In one embodiment, the inlet valve and the outlet valve are arranged at one end of a lever arm, said end of the lever arm acting alternately on the two valves.This embodiment is space-saving and allows a compact design.

[0011] In one embodiment, the inlet and outlet valves are arranged at opposing first and second ends of a lever arm, with the first end acting on the inlet valve and the second end acting on the outlet valve. This allows for additional freedom in the design of the metering assembly, particularly with respect to the placement of the inlet and outlet valves relative to other components. Furthermore, it is possible to actuate different valves using different mechanical advantages. In this embodiment, the lever arm moves between a first position and a second position like a rocker or seesaw.

[0012] In one embodiment, the force-generating member is a piezoelectric element, preferably in the form of a piezoelectric stack. Piezoelectric elements are commonly referred to as piezoelectric actuators and operate based on known physical principles. Applying power to a piezoelectric element causes it to expand and / or extend. De-energizing the element causes it to return to its unexpanded / unextended (original) size. The use of a piezoelectric stack (a known form of piezoelectric element) allows for a slender design while providing a relatively large range of motion / displacement for the force-generating element. Piezoelectric elements are highly useful components because they have the ability to change shape in response to voltage. When a positive voltage is applied, they expand, while a negative voltage causes them to contract. The degree of expansion varies depending on both the length of the piezoelectric element and the applied voltage. This means that the longer the piezoelectric element and the higher the voltage, the greater the expansion. Furthermore, the material of the piezoelectric element generates a resistive force that depends on both the voltage and the cross-section of the piezoelectric element. A larger cross-section and a higher voltage result in a greater resistive force that can be generated and transmitted. The present invention exploits the unique properties of the piezoelectric element / its material. In one embodiment, its expansion is exploited and amplified using the lever arm to achieve the desired amount of movement. This ensures operation within the required force working range while still achieving the desired displacement.

[0013] In one embodiment, the inlet valve and the outlet valve each comprise a movable ball valve element, a fixed valve seat and a biasing element, which biases the ball valve element into the valve seat, wherein the actuator acts at least indirectly on the ball valve element. This embodiment allows for a further simplified and very robust design. Preferably, the biasing element is a spring element, in particular a coil spring. The biasing element pushes the ball valve element into the valve seat, thereby biasing the respective valve into its closed position. In one embodiment, the actuator acts directly on the ball valve element to open the respective valve. In another embodiment, the action is indirect via a transmission member or the like.

[0014] In one embodiment, the inlet valve and the outlet valve each include an axially movable transmission member extending longitudinally between a first end and a second end, wherein the first end of the transmission member is configured to contact the actuator, and the second end of the transmission member is configured to contact the ball valve element. The transmission member is configured to transmit the force and / or movement of the force-generating member to the respective valve, in particular to the respective ball valve element. The transmission member can have a single-part or multi-part design. This embodiment allows the actuator to be positioned further away from the valve, and thus further away from the fluid-carrying components / portions of the metering assembly.

[0015] With respect to an implantable infusion device, the aforementioned objects are achieved by providing an actuator device that is movable between a first position and a second position for alternately actuating an inlet valve or an outlet valve, wherein in the first position, the actuator mechanically actuates the inlet valve and does not actuate the outlet valve, and wherein in the second position, the actuator mechanically actuates the outlet valve and does not actuate the inlet valve. To avoid repetition, reference is made to the disclosure / description regarding the metering assembly according to the present invention and its embodiments. Said disclosure / description also applies, mutatis mutandis, to the implantable infusion device according to the present invention and the corresponding embodiments of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In all drawings, the same elements are represented by the same reference numerals. The accompanying drawings schematically show:

[0017] Figure 1 is an illustration of one embodiment of an implantable infusion device according to the present invention having one embodiment of a metering assembly according to the present invention, the metering assembly being depicted in cross-section;

[0018] Figure 2 For another cross-sectional view relative to the longitudinal cross-sectional plane Figure 1 The metering assembly shown in ;

[0019] Figure 3 Based on Figure 1 and Figure 2 a cross-sectional view of a valve of a metering assembly;

[0020] Figure 4 is a longitudinal sectional view of another embodiment of a metering device according to the present invention; and

[0021] Figure 5 Based on Figure 4 Another longitudinal cross-sectional view of the metering component. DETAILED DESCRIPTION

[0022] refer to Figure 1, the implantable infusion device 1 comprises a pressurized infusion fluid reservoir 2, an infusion fluid dispensing member 3 and a metering assembly 4. The implantable infusion device 1 is configured to deliver an infusion fluid F, i.e., a medical fluid or a fluid drug, to a patient. Figure 1 In the configuration depicted in , the infusion device 1 is implanted in the body B of a patient.

[0023] The infusate reservoir 2 contains a pressurized volume of infusate F to be infused. Within the infusate reservoir 2, the infusate F is pressurized at a reservoir pressure p1. The reservoir pressure p1 is generated using known techniques and can be constant or variable. The technical details of the pressurized infusate reservoir 2 are not within the scope of the present invention. Therefore, a more detailed description of the specific design and function of the pressurized infusate reservoir 2 is unnecessary.

[0024] The infusate dispensing member 3 is configured to dispense infusate F from the infusate reservoir 2 to a site inside the patient's body B. The infusate dispensing member 3 is fluidly connected to the infusate reservoir 2 via a metering assembly 4 .

[0025] In the embodiment shown, the infusate dispensing member 3 is a catheter 31 having a distal end 32 and a proximal end 33. The distal end 32 may also be referred to as the catheter tip and is located at the site inside the body B. The proximal end 33 is fluidically connected to the metering assembly 4.

[0026] In the illustrated embodiment, the pressurized infusate reservoir 2 and the metering assembly 4 are arranged in a housing (not depicted in detail). The housing containing the infusate reservoir 2 and the metering assembly 4 is made of a biocompatible material and is implanted in the patient's body B. In an embodiment not shown in the figures, the pressurized infusate reservoir and the metering assembly each include a separate housing, which is implanted at a different location in the patient's body.

[0027] The metering assembly 4 comprises an inlet line 5 , an outlet line 6 , an infusate reservoir 7 with a reservoir volume 8 , an inlet valve 9 , an outlet valve 10 and an actuator device 11 .

[0028] The inlet conduit 5 is fluidically connected to the pressurized infusate reservoir 2. The fluid connection is schematically depicted by means of a dashed line extending between the infusate reservoir 2 and the inlet conduit 5, as shown in FIG. Figure 1 The inlet conduit 5 is configured to receive a flow of infusate from the pressurized infusate reservoir 2 .

[0029] The outlet conduit 6 is fluidically connected to the infusate dispensing member 3. The fluid connection is schematically depicted by a dashed line extending between the outlet conduit 6 and the infusate dispensing member 3, as shown in FIG. Figure 1The outlet conduit 6 is configured to deliver the infusate flow to the fluid dispensing member 3 , ie the catheter 31 . In the embodiment shown, the outlet conduit 6 is fluidly connected to the proximal end 33 of the fluid dispensing member 3 in the form of the catheter 31 .

[0030] The infusate accumulator 7 comprises an accumulator volume 8. The infusate accumulator 7 is configured to accumulate a defined fixed volume of infusate received from the infusate reservoir 2 and delivered to the infusate dispensing member 3. The fixed volume is accumulated inside the accumulator volume 8. The accumulator volume 8 is in line with the inlet conduit 5 and the outlet conduit 6.

[0031] The inlet valve 9 is in fluid communication with the inlet conduit 5 and the accumulator volume 8. In other words, the inlet valve 9 is in line with the inlet conduit 5 and the accumulator volume 8. The inlet valve 9 controls the flow of infusate from the infusate reservoir 2 into the accumulator volume 8.

[0032] The outlet valve 10 is in fluid communication with the accumulator volume 8 and the outlet conduit 6. In other words, the outlet valve 10 is in line with the accumulator volume 8 and the outlet conduit 6. The outlet valve 10 controls the flow of infusate from the accumulator volume 8 into the fluid dispensing member 3.

[0033] Both the inlet valve 9 and the outlet valve 10 are normally closed. This means that if and when the valves 9, 10 are not actuated by means of the actuator means 11, the flow of infusate through the valves 9, 10 is blocked.

[0034] The actuator device 11 is configured to actuate the inlet valve 9 and the outlet valve 10 between a first state and a second state. In the first state, the inlet valve 9 is open and the outlet valve 10 is closed. The open inlet valve 9 allows a flow of infusate from the infusate reservoir 2 through the inlet conduit 5 into the accumulator volume 8. The closed outlet valve 10 simultaneously blocks a flow of infusate from the accumulator volume 8 through the outlet conduit 6 and into the fluid dispensing member 3. In the second state, the inlet valve 9 is closed and the outlet valve 10 is open. The closed inlet valve 9 blocks a flow of infusate from the infusate reservoir 2 through the inlet conduit 5 into the accumulator volume 8. At the same time, the open outlet valve 10 allows a flow of infusate from the accumulator volume 8 through the outlet conduit 6 into the fluid dispensing member 3.

[0035] Cycling or switching between the first state and the second state causes filling and draining of the accumulator volume 8, i.e., "pumping", whereby the rate of switching or cycling defines the amount of infusate F infused per unit time, and thus the dose of infusate F delivered to the patient. The amount of infusate F per unit time may also be expressed as the infusate rate F R .

[0036] The aforementioned "pumping" action can be described in more detail as follows: In a first step, the inlet valve 9 is open and the outlet valve 10 is closed, ie the valves 9 , 10 are in the aforementioned first state. Thus, the accumulator device 7 is filled to its fixed accumulator volume 8 .

[0037] In a second step, the entire accumulator volume 8 is discharged through the outlet duct 6 by actuating the valves 9 , 10 into the second state (inlet valve 9 closed, outlet valve 10 open).

[0038] Thus, the accumulator device 7 , more specifically its accumulator volume 8 , is alternately filled and emptied by the switching action of the valves 9 , 10 .

[0039] In the embodiment shown, the accumulator device 7 operates on the basis of known principles and comprises a design that is at least known in principle. Thus, the accumulator device 7 operates at an accumulator pressure p2 that is between the reservoir pressure p1 and the pressure p3 inside the patient's body B. The pressure p3 inside the patient's body B can be atmospheric pressure or a cardiovascular pressure slightly above atmospheric pressure. This pressure setting (i.e., p1 > p2 > p3) results in the aforementioned pumping action.

[0040] In the particular embodiment shown, the accumulator device 7 comprises an accumulator chamber 71 , a pressure chamber 72 , a diaphragm 73 , a rear stop surface 74 and a front stop surface 75 .

[0041] It is worth emphasizing that the depicted design of the accumulator device is optional and not essential to the invention. Therefore, the embodiments not shown in the figures include differently designed accumulator devices.

[0042] Now referring further to the specific design of the accumulator device 7 of the illustrated embodiment, a diaphragm 73 is arranged in the accumulator chamber 71. The diaphragm 73 is arranged in the accumulator chamber 71. Figure 1 The second position of the diaphragm 73 is deflectable between the first position and the second position depicted in FIG. Figure 1 The interior of the accumulator chamber shown in FIG is schematically illustrated using dashed lines. In its first position, the diaphragm 73 rests flat against the front stop surface 75. In its second position, the diaphragm 73 is deflected from the front stop surface 75 and pressed against the rear stop surface 74, thereby defining the fixed accumulator volume 8 within the accumulator chamber 71. The pressure chamber 72 is pressurized to the accumulator pressure p2 and is in fluid communication with the rear surface of the diaphragm 73, opposite the accumulator volume 8. It is worth noting that the embodiment not shown in the figures does not include the pressure chamber 72.

[0043] Referring again to the aforementioned steps of the pumping action, when the diaphragm 73 is in its first position, the accumulator volume 8 is empty. Opening the inlet valve 9 while maintaining the outlet valve 10 closed causes the inflowing infusate to deflect the diaphragm 73 into its second position, thereby filling the accumulator chamber 71 and / or the accumulator volume 8 to its defined fixed volume. Then, closing the inlet valve 9 and opening the outlet valve 10 (i.e., actuating the valves 9, 10 to their second states) causes the accumulator pressure p2 to press the diaphragm 73 back into its first position, flat against the front stop surface 75, thereby emptying and discharging the accumulator volume 8 through the outlet conduit 6.

[0044] Since p1 > p3 , opening both valves 9 , 10 simultaneously would cause an uncontrolled flow of infusate from the infusate reservoir 2 through the metering assembly 4 , from there directly into the fluid dispensing member 3 and further into the patient's body B. This would result in an uncontrolled delivery of infusate F to the patient.

[0045] In order to avoid the risk of such uncontrolled infusion fluid delivery, the actuator device 11 includes an actuator 12, which is movable between a first position and a second position for alternating actuation of the inlet valve 9 or the outlet valve 10 between the first state and the second state, wherein, in the first position, the actuator 12 actuates the inlet valve 9 and does not actuate the outlet valve 10, and wherein, in the second position, the actuator 12 actuates the outlet valve 10 and does not actuate the inlet valve 9.

[0046] Since both valves 9, 10 are normally closed and are actuated alternately by the same actuator 12, it is not possible to open both valves 9, 10 simultaneously by means of the actuator 12. Alternating actuation of both valves 9, 10 by means of the same actuator 12 results in increased safety and a simple design.

[0047] refer to Figure 1 and Figure 2 , depicting the first position of actuator 12. Since valves 9 and 10 are both normally closed, the first position of actuator 12 controls the first state of valves 9 and 10, and the second position of actuator 12 controls the second state of valves 9 and 10. In other words, moving actuator 12 from its second position into its first position opens inlet valve 9 and deactivates actuation of outlet valve 10, thereby causing it to close. Moving actuator 12 from its first position into its second position deactivates actuation of inlet valve 9, thereby causing it to close, while outlet valve 10 is actuated and thereby opened.

[0048] Now refer to Figure 2, the actuator 12 includes an actuator member 13 and a force-generating member 14. The actuator member 13 is configured to act directly or indirectly on the valves 9, 10 by means of force and / or motion (i.e., mechanically). The force-generating member 14 is configured to generate a force and / or motion for moving the actuator member 13 between its first and second positions. It is worth mentioning that such a design of the actuator 12 is optional. Therefore, in an embodiment not shown in the figures, the function of generating force and / or motion and the function of acting on the valves are integrated into the same member.

[0049] In the illustrated embodiment, the actuator 12 further includes a biasing member 15. The biasing member 15 is configured to bias the actuator member 12 against the force and / or movement of the force-generating member 14. The biasing member 15 is optional and, in particular, is not required when the force-generating member 14 is configured to move the actuator member 13 back and forth between a first position and a second position. However, in the illustrated embodiment, the force-generating member 14 is configured to move the actuator member 12 from its first position to its second position (but not vice versa) and to resist the bias of the biasing member 15. In the illustrated embodiment, it is not possible to move the actuator member 13 from its second position to its first position solely with the aid of the force-generating member 14. Instead, the movement of the actuator member 13 is initiated with the aid of the biasing member 15. Of course, other embodiments are contemplated in which the force-generating member is configured to move the actuator member from its second position to its first position, but not vice versa.

[0050] In the embodiment shown, the actuator member 13 is a lever arm 16. The lever arm 16 is movable between a first position and a second position by means of the force generating member 14, thereby amplifying the movement of the force generating member 14 into an amplified actuating movement acting on the inlet valve 9 or the outlet valve 10, respectively.

[0051] The lever arm 16 extends longitudinally between a first end 161 and a second end 162 (see Figure 2 ).exist Figure 1 and Figure 2 In the embodiment shown in FIG, the first end 161 acts alternately on the inlet valve 9 or the outlet valve 10 .

[0052] In the embodiment shown, the lever arm 16 is hinged at a pivot 163 and is thus pivotally movable between its first position and its second position. The pivot 163 may also be referred to as a fulcrum.

[0053] In the embodiment shown, the biasing member 15 is arranged at the second end 162 of the lever arm 16. The force generating member 14 is located between the pivot 163 and the first end 161 of the lever arm 16. The distance between the first end 161 and the pivot 163, acting on the valves 9, 10, and the distance between the force generating member 14 and the pivot 163, define the magnification of the lever arm 16, i.e., the leverage and / or mechanical advantage.

[0054] In the embodiment shown, the movement M1 generated by means of the force-generating member 14 is amplified to the actuating movement M2 at a ratio of 1:20.

[0055] The described mechanical lever principle also applies mutatis mutandis with respect to the biasing produced by means of the biasing member 15 .

[0056] In an embodiment not shown in the figures, the force generating member is located, for example, at the second end of the lever arm, and the biasing member is located, for example, between the pivot and the first end. Figure 2 The specific arrangements of the force generating member 14 , biasing member 15 , and pivot 163 depicted in FIG. 1 relative to each other and relative to the first and second ends 161 , 162 are exemplary and may be different in other embodiments.

[0057] Furthermore, with reference to an embodiment not shown in the figures, the lever arm is fixedly mounted and flexibly bendable between a first position and a second position. Figure 2 The pivot 163 shown in FIG. 1 is optional.

[0058] In the embodiment shown, the force generating member 14 is a piezoelectric element 141. In the embodiment shown, the piezoelectric element 141 is in the form of a piezoelectric stack 142 (ie, a longitudinally shaped piezoelectric element), but other shapes and forms are possible.

[0059] The piezoelectric element 141 operates on the basis of known physical principles. Specifically, the piezoelectric element 141 extends and / or expands when receiving electrical energy. When the power is removed, the piezoelectric element 141 returns to its original, unexpanded / unextended state.

[0060] In the embodiment shown, the energization and de-energization of the piezoelectric element 141 is controlled by means of a control unit 143. Said control unit 143 can be provided as an integrated component of the metering assembly 4. Alternatively, the control unit 143 can be provided as a separate component connected to the metering assembly 4, in particular the piezoelectric element 141. Figure 2, a control unit 143 is schematically depicted, wherein the connection to the piezoelectric element 141 is indicated by means of a dashed line. In an embodiment not shown in the figure, the control unit is not part of the device 1, but is a separate unit external to the patient's body B and connected to the device by means of a suitable wireless connection. Therefore, the control unit 143 is optional and not essential to the present invention.

[0061] In the embodiment shown, energizing the piezoelectric element 141 causes one end 144 of the piezoelectric element 141 to move and press against the lever arm 16. This causes the lever arm 16 to pivot about the pivot 163 (relative to the Figure 2 ) pivotally moves in a counterclockwise direction, whereby its first end 161 acts on the outlet valve 10. In its energized state, the piezoelectric element 141 operates against the bias of the biasing member 15. De-energizing the piezoelectric element 141 causes the end 144 to move away from the lever arm 16, thereby giving way to the clockwise pivotal movement of the lever arm 16 caused by the bias of the biasing member 15. Consequently, the first end 161 moves away from the outlet valve 10, deactivating its actuation and actuating the inlet valve 9 instead.

[0062] In the embodiment shown, the inlet valve 9 and the outlet valve 10 comprise Figure 3 The specific design is shown with respect to the inlet valve 9. The inlet valve 9 and the outlet valve 10 are identical. Therefore, the following description of the details of the inlet valve 9 also applies with respect to the outlet valve 10, mutatis mutandis.

[0063] Now refer to Figure 3 , the inlet valve 9 comprises a movable ball valve element 91, a fixed valve seat 92 and a biasing element 93. The biasing element 93 biases the ball valve element 91 into the valve seat 92, thereby closing the inlet valve 9 and thus causing a normally closed state of the inlet valve 9. The actuator 12 and more specifically the actuator member 13 ( Figure 3 ) acts on the ball valve element 91 and resists the bias of the biasing element 93.

[0064] In the embodiment shown, the actuator 12 acts indirectly on the ball valve element 91 by means of a transmission member 94 of the inlet valve 9. The actuating movement M2 of the actuator 12 is transmitted to the ball valve element 91 by means of said transmission member 94 in order to open the inlet valve 9.

[0065] In the embodiment shown, both valves 9, 10 further comprise a valve inlet passage 95 and a valve outlet passage 96. With respect to the inlet valve 9, the valve inlet passage 95 is fluidly connected to the inlet conduit 5, while the valve outlet passage 96 is fluidly connected to the accumulator volume 8. Now with respect to the outlet valve 10, its valve inlet passage 95 is fluidly connected to the accumulator volume 8, while its valve outlet passage 96 is fluidly connected to the outlet conduit 6.

[0066] The ball valve element 91 and the valve seat 92 are in line with the valve inlet passage 95 and the valve outlet passage 96. Moving the ball valve element 91 away from the valve seat 92 allows infusate flow between the valve inlet passage 95 and the valve outlet passage 96.

[0067] The transfer member 94 extends longitudinally between a first end 941 and a second end 942. The first end 941 is configured to be contacted by the actuator 12, or more specifically, with respect to the illustrated embodiment, by the first end 161 of the lever arm 16. The second end 942 of the transfer member 94 is configured to contact the ball valve element 91. The transfer member 94 is axially movable by means of the lever arm 16 in order to open the valve 9. More specifically, moving the lever arm 16 to its first position causes the first end 161 of the lever arm 16 to press against the first end 941 of the transfer member 94, thereby transferring the actuating motion M2 to the ball valve element 91, moving the ball valve element 91 away from the valve seat 92 and thereby opening the inlet valve 9. Moving the lever arm 16 back to its second position causes the bias of the biasing element 93 to move the ball valve element 91 back into the valve seat 92, thereby also moving the transfer member 94 back to its original position.

[0068] In the embodiment shown, the transfer member 94 has a two-part design including a first transfer pin 943 and a second transfer pin 944. The pins 943, 944 are coaxial with each other and with the ball valve element 91. The first transfer pin 943 includes a second end 942 and is positioned in line with the valve seat 92 and the valve outlet channel 96. Therefore, the first transfer pin 943 is located in the fluid-carrying area of ​​the valve 9. In contrast, the second pin 944 is located in the "dry" area of ​​the valve 9 that does not carry fluid. The second transfer pin 944 includes a first end 941 and a contact end 9441 of the transfer member 94. The contact end 9441 is opposite to the first end 941 and contacts the complementary contact end 9431 of the first transfer pin 943 via a fluid-tight flexible diaphragm 97, which fluidly separates the fluid-carrying area and the dry area of ​​the inlet valve 9.

[0069] Figure 4 and Figure 5 The figure shows another embodiment of the metering component 4a according to the present invention. Figures 1 to 3 The metering assembly 4 of the embodiment is substantially identical. To avoid repetition, only the relevant differences of metering assembly 4a relative to metering assembly 4 will be described. Unless otherwise described, the disclosure regarding metering assembly 4 also applies mutatis mutandis to metering assembly 4a. Therefore, not all features / details of metering assembly 4a will be described separately. Instead, reference is made to the description of metering assembly 4.

[0070] according to Figure 4 and Figure 5The metering assembly 4a differs in that the inlet valve 9a and the outlet valve 10a are arranged at opposite ends 161a and 162a of a lever arm 16a. The inlet valve 9a is arranged at the first end 161a, and the outlet valve 10a is arranged at the second end 162a. The first end 161a is configured to actuate the inlet valve 9a, while the second end 162a is configured to actuate the outlet valve 10a. The lever arm 16a is hinged at a pivot 163a and is thus pivotally movable between a first position, in which the first end 161a actuates opening of the inlet valve 9a, and a second position, in which the second end 162a actuates opening of the outlet valve 10a. The pivot 163a is located substantially midway between the first end 161a and the second end 162a. The force-generating member 14a acts at a contact point (not referenced) longitudinally between the first end 161a and the pivot 163a, thereby forming a T-shape with the lever arm 16a. The biasing member 15a contacts the lever arm 16a at a contact point (not referenced) located longitudinally between the second end 162a and the pivot 163a.

Claims

1. A metering assembly (4, 4a) for an implantable infusion device (1), comprising: an inlet conduit (5) configured for fluid connection with a pressurized infusion fluid reservoir (2) of the infusion set (1); an outlet conduit (6) configured for fluid connection with an infusion liquid dispensing member (3) of the infusion set (1); an infusion fluid accumulator (7, 7a), the infusion fluid accumulator (7, 7a) having an accumulator volume (8); an inlet valve (9, 9a) in fluid communication with the inlet conduit (5) and the accumulator volume (8); an outlet valve (10, 10a) in fluid communication with the accumulator volume (8) and the outlet conduit (6); wherein both the inlet valve (9, 9a) and the outlet valve (10, 10a) are normally closed; and an actuator device (11) configured to actuate the inlet valve (9, 9a) and the outlet valve (10, 10a) between a first state and a second state, wherein, in the first state, the inlet valve (9, 9a) is open and the outlet valve (10, 10a) is closed, thereby allowing the flow of infusate into the accumulator volume (8) through the inlet conduit (5) while blocking the flow of infusate from the accumulator volume (8) through the outlet conduit (6), and wherein, in the second state, the inlet valve (9, 9a) is closed and the outlet valve (10, 10a) is open, thereby allowing the flow of infusate from the accumulator volume (8) through the outlet conduit (6) while blocking the flow of infusate into the accumulator volume (8) through the inlet conduit (5); It is characterized by The actuator device (11) comprises an actuator (12, 12a) movable between a first position and a second position for alternately actuating the inlet valve (9, 9a) or the outlet valve (10, 10a) between the first state and the second state, wherein, in the first position, the actuator (12, 12a) mechanically actuates the inlet valve (9, 9a) and does not actuate the outlet valve (10, 10a), and wherein, in the second position, the actuator (12, 12a) mechanically actuates the outlet valve (10, 10a) and does not actuate the inlet valve (9, 9a).

2. The metering assembly (4, 4a) according to claim 1, wherein The actuator (12, 12a) comprises: an actuator member (13, 13a) which acts alternately on the inlet valve (9, 9a) or the outlet valve (10, 10a); and a force generating member (14, 14a) which is operatively coupled to the actuator member (13, 13a) and is configured to generate a force and / or motion for moving the actuator member (13, 13a) between the first position and the second position.

3. The metering assembly (4, 4a) according to claim 2, wherein The actuator (12, 12a) includes a biasing member (15, 15a) operatively coupled to the actuator member (13, 13a) and biasing the actuator member (13, 13a) against the force and / or movement of the force generating member (14, 14a).

4. The metering assembly (4, 4a) according to claim 2 or 3, wherein The actuator member (13, 13a) is a lever arm (16, 16a) which is movable between the first position and the second position by means of the force generating member (14, 14a), the lever arm (16, 16a) amplifying the movement of the force generating member (14, 14a) into an amplified actuating movement.

5. The metering assembly (4, 4a) according to claim 4, wherein The lever arm (16, 16a) is hinged at a pivot (163, 163a) and is pivotally movable between the first position and the second position.

6. The metering assembly according to claim 4, wherein: The lever arm is fixedly mounted and flexibly bendable between the first position and the second position.

7. The metering assembly (4, 4a) according to any one of claims 4 to 6, wherein The inlet valve (9) and the outlet valve (10) are arranged at one end (161) of the lever arm (16), and the end (161) of the lever arm (16) acts alternately on the two valves (9, 10).

8. The metering assembly (4a) according to any one of claims 4 to 6, wherein The inlet valve (9a) and the outlet valve (10a) are arranged at opposite first ends (161a) and second ends (162a) of the lever arm (16a), wherein the first end (161a) acts on the inlet valve (9a) and the second end (162a) acts on the outlet valve (10a).

9. The metering assembly (4, 4a) according to any one of claims 2 to 8, wherein The force generating member (14, 14a) is a piezoelectric element (141, 141a), preferably in the form of a piezoelectric stack (142, 142a).

10. The metering assembly (4, 4a) according to any one of the preceding claims, wherein The inlet valve (9, 9a) and the outlet valve (10, 10a) each comprise a movable ball valve element (91), a fixed valve seat (92) and a biasing element (93), the biasing element (93) biasing the ball valve element (91) into the valve seat (92), wherein the actuator (12, 12a) acts at least indirectly on the ball valve element (91).

11. The metering assembly (4, 4a) according to claim 10, wherein The inlet valve (9, 9a) and the outlet valve (10, 10a) each include an axially movable transfer member (94) extending longitudinally between a first end (941) and a second end (942), wherein the first end (941) of the transfer member (94) is configured to contact the actuator (12, 12a) and the second end (942) of the transfer member (94) is configured to contact the ball valve element (91).

12. An implantable infusion device (1) for delivering an infusion fluid (F) to a patient, comprising: Pressurized infusion fluid reservoir (2); Infusion liquid dispensing member (3); a metering assembly (4, 4a), the metering assembly (4, 4a) comprising an inlet conduit (5) in fluid communication with the infusate reservoir (2) and an outlet conduit (6) in fluid communication with the infusate dispensing member (3), an infusate accumulator (7, 7a) having an accumulator volume (8), an inlet valve (9, 9a) in fluid communication with the inlet conduit (5) and the accumulator volume (8), an outlet valve (10, 10a) in fluid communication with the accumulator volume (8) and the outlet conduit (6), and an actuator device (11) configured to actuate the inlet valve (9, 9a) and the outlet valve (10, 10a) between a first state and a second state, wherein both the inlet valve (9, 9a) and the outlet valve (10, 10a) are normally closed; wherein, in the first state, the inlet valve (9, 9a) is open and the outlet valve (10, 10a) is closed, thereby allowing the flow of infusate from the infusate reservoir (2) into the accumulator volume (8) while blocking the flow of infusate from the accumulator volume (8) through the infusate dispensing member (3); and wherein, in the second state, the inlet valve (9, 9a) is closed and the outlet valve (10, 10a) is open, thereby allowing the flow of infusate from the accumulator volume (8) through the infusate dispensing member (3) while blocking the flow of infusate from the infusate reservoir (2) into the accumulator volume (8); It is characterized by The actuator device (11) comprises an actuator (12, 12a) movable between a first position and a second position for alternate actuation of the inlet valve (9, 9a) or the outlet valve (10, 10a), wherein, in the first position, the actuator (12, 12a) mechanically actuates the inlet valve (9, 9a) and does not actuate the outlet valve (10, 10a), and wherein, in the second position, the actuator (12, 12a) mechanically actuates the outlet valve (10, 10a) and does not actuate the inlet valve (9, 9a).

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