HK1226674A1 - Ambulatory infusion system including a step switching mechanism for valve control - Google Patents

Description

Portable infusion system including a step switch mechanism for valve control

Technical Field

The present disclosure is in the field of dosing units for ambulatory infusion systems. The present disclosure is also in the field of drive units for use in combination with drug delivery units and portable infusion systems for infusing liquid drugs into the body of a patient over an extended period of time. Furthermore, the present disclosure is in the field of methods for coupling a dosing unit and a drive unit.

Background

Portable infusion devices are well known in the art, for example in the treatment of diabetes by subcutaneous continuous infusion of insulin (CSII) and in the treatment of pain or cancer, and are available from a number of suppliers, such as Roche diagnostics gmbh, Germany, or Medtronic minimed inc, CA, USA.

These portable infusion devices or systems are typically of the syringe-driver type, according to a classical and widely accepted design. Many disadvantages of such devices are well known in the art. In particular, they have limited accuracy because they involve delivering very small amounts of drug, typically in the nanoliter range, from a cartridge having a total drug volume in the milliliter range. Therefore, further principles and architectures have proposed the use of dedicated dosing units downstream from the drug reservoir, comprising, for example, a micro-membrane pump or a micro-piston pump, as well as a precise metering adapted to be coupled to the drug reservoir and designed in particular for small volumes. Although several designs for such administration units are known in the art, they are quite complex, most of them being expensive and/or critical with respect to large scale.

EP1970677a1 discloses a system with a miniaturized metering piston pump having a dosing cartridge that is repeatedly coupled to and filled from a larger reservoir, subsequently coupled to an infusion site, and infused with liquid drug in progressive steps and over an extended period of time. In order to have the dosing cartridge alternatively coupled to the reservoir and the infusion site, a valve system is proposed.

Disclosure of Invention

EP2163273a1 discloses a dosing unit according to the principles established in EP1970677a 1. According to this disclosure, the dosing unit is (typically releasably) coupled to a separate drive unit for both piston movement and valve switching depending on the plunger position. The valve switch is effected by moving (e.g. rotating) the dosing cartridge of the dosing unit relative to a fixed valve member, thereby establishing an exchangeable fluid communication of the dosing cartridge with either the inlet or the outlet.

It is a general object of the present disclosure to provide an alternative design for a portable infusion system with separate actuation for piston displacement and valve switching, and components thereof. This object is achieved by the subject matter of the independent claims. Specific exemplary embodiments are defined by the respective dependent claims and by the embodiments described in the present description and the drawings.

According to the present disclosure, an administration unit for a portable infusion system may include a metering pump unit and a valve unit. The valve unit may have a fill port designed to fluidly couple with a liquid drug reservoir and an exhaust port designed to fluidly couple with an infusion site interface. The valve unit may further comprise a shut-off valve (shut-off) body which is movable between a filling position in which it fluidly couples the filling port with the dosing cylinder of the pump unit, and an alternate discharge position in which it fluidly couples the dosing cylinder of the pump unit with the discharge port. The dosing unit may further comprise a valve driver coupling coupled to or integral with the shut-off valve body and acting as an output element of a step switching mechanism (stepswitching mechanism).

For operation of the dosing unit, the valve driver is operatively coupled to the valve actuator via the valve driver, the valve driver and the valve driver coupling in combination forming a step switch mechanism. As will be discussed in more detail below in the context of exemplary embodiments, coupling the valve unit with a coupling valve actuator via a step switch mechanism demonstrates a number of advantages. In particular, it allows the valve transmission to operate with relatively low accuracy requirements. Furthermore, it is advantageous for a simple and convenient assembly and disassembly of the modular infusion system.

The pump unit may particularly be designed as a miniaturized piston pump with a dosing cartridge and a piston arranged for sealing sliding engagement inside said dosing cartridge, e.g. in a bore extending along the centre axis of said dosing cartridge, i.e. coaxial with the cartridge axis. It should be noted that the term "aperture" (here and below) does not imply any limitation with respect to the manufacturing process. The dosing cartridge may be manufactured as the other components of the dosing unit, e.g. by machining, injection moulding, 3D printing or other manufacturing techniques which may be used alone or in combination.

The cartridge and piston in combination define a variable volume metering chamber in a syringe-like manner, wherein the volume is defined by the cross-sectional area of the bore and the piston position. There is a fluid coupling between the metering chamber and the valve unit, such that the fluid coupling to the cartridge and the valve unit is used for sucking the liquid drug into the metering chamber via the valve unit, and alternatively transferring the liquid drug from the metering chamber. The piston may be movable between a most distal position and a most proximal position, wherein the most distal position corresponds to a maximum volume of the metering chamber and the most proximal position corresponds to a minimum and e.g. negligible volume of the metering chamber. The volume of the metering chamber is also referred to as the fill volume of the dosing cartridge. In typical embodiments, which may be used, for example, in the CSII field, the maximum fill volume may, for example, be in the range of 10 μ Ι to 200 μ Ι, corresponding to 1 to 20 units of liquid U100 insulin formulation. In a particular embodiment, the maximum fill volume is in the range of 50 μ l to 100 μ l, e.g. 60 μ l. The diameter of the bore may be in the range of a few millimeters, causing the piston to displace in the range of a few millimeters to a few centimeters.

As will be discussed further below, the piston may be coupled to a pump drive for reciprocating displacement in incremental or nearly infinite steps, thereby allowing for variation in fill volume in incremental or nearly infinite steps.

The shut-off valve body can have a variety of designs depending on the particular valve design. In a typical embodiment, it is an axially symmetric body with several radial and/or axial liquid channels for controlling the flow. Advantageously, there is at least one position in the shut-off valve body, in particular an intermediate position between the filling position and the discharge position, in which position the pump port is neither coupled to the filling port nor to the discharge port and the metering chamber is accordingly fluidically isolated.

In some embodiments, the valve actuator coupling includes a star wheel or star wheel portion, a sheave or a sheave portion (Geneva-typewheel section). As will be described in the context of exemplary embodiments below, the geneva wheel may be used as an output element particularly suited to the switchgear design of the present application. However, other types of step switch mechanisms may be used.

In some embodiments, the shut-off valve body is designed as a generally cylindrical body. The cylinder body may illustratively have a diameter of 3 mm or less, for example 1.5 mm. In a variant, the diameter may be varied in a plurality of steps along its length or continuously, the latter resulting in a conical shut-off valve body. The small size of the valve and in particular of the shut-off valve body is advantageous for several reasons, such as minimizing the dead volume of the fluid and the overall size.

In some embodiments, the shut-off valve body is made of a hard material, in particular a hard plastic, and the shut-off valve body contact surface of the valve housing is made of a soft material, in particular a rubber or a thermoplastic elastomer. Other soft plastics may also be used. Such a design is advantageous for sealing.

In some embodiments, the shutoff valve body is designed for rotatable movement about a valve axis of rotation. For embodiments of this type, the valve unit is designed as a rotary valve, wherein the valve state is determined by the rotational position of the shut-off valve body relative to the valve housing. For this type of embodiment, the filling position and the draining position are the rotational positions of the shut-off valve body, respectively, as described above, in which the fluid passage of the shut-off valve body is aligned with the filling port or the draining port, which are realized as bores in the valve housing. Alternatively, however, the valve unit may be realized in different ways, for example as a sliding valve with a linearly sliding shut-off valve body, or in a combination of a rotational movement and a sliding movement.

In some embodiments, the valve axis of rotation is parallel or perpendicular to the piston displacement axis of the pump unit. Any of those designs, which will be explained in more detail further below in the context of exemplary embodiments, allows for a particularly compact and user-friendly design.

In some embodiments, the valve actuator coupling includes an engagement groove for engaging with an engagement pin of the valve actuator as the drive element of the step switch mechanism.

In some embodiments, the dosing unit is designed to be releasably coupled with the drive unit. The releasable coupling of the dosing unit with the drive unit allows for the design of a modular portable infusion system, e.g. with a durable unit comprising the drive unit and which may comprise a user interface, control circuitry, etc. and a disposable unit designed for a single application, e.g. only a few days, and which may comprise a dosing unit and a liquid drug reservoir. For such modular designs, it is presented below that controlling the valve via a step switch mechanism is particularly advantageous for coupling and decoupling, as will be discussed further in more detail below. Alternatively, however, the dosing unit may be wholly or partly integrally formed with the drive unit.

The term "releasable coupling" correspondingly refers to a design allowing mechanical coupling and uncoupling of the drug delivery unit and the drive unit, substantially in the form of a substantially rigid mechanical coupling and in addition being able to be uncoupled subsequently, wherein uncoupling at least does not cause damage to the drive unit. For this purpose, corresponding mechanical mounting structures may be provided at both the dosing unit and the drive unit, as will be further described below. The mechanical coupling of the dosing unit to the drive unit advantageously couples at the same time the valve unit (in particular, the valve driver coupling) and the valve transmission of the dosing unit as well as the position of the piston drive of the dosing unit.

According to a further aspect, the present disclosure is directed to a drive unit. The drive unit may comprise a pump drive (pump drive) which comprises a pump actuator and a pump drive coupled to the pump actuator, which pump drive is designed for coupling to the piston of the metering pump unit for transmitting a pump drive force and/or a pump drive torque from the pump actuator to the piston of the pump unit. The drive unit may further comprise a valve transmission comprising a valve actuator and a valve driver coupled to the valve actuator, the valve driver being designed for coupling to a valve driver coupling of the valve unit for transmitting a valve switching force and/or a valve switching torque from the valve actuator to the valve unit, wherein the valve driver is a drive element of the step switch mechanism.

In some embodiments, the valve actuator includes an engagement pin for engaging the valve actuator coupling. The engagement pin is eccentric on the valve actuator body. The valve actuator may further include a center pin aligned with the valve gear output shaft. In operation, the engagement pin moves correspondingly in a circular path about the center pin.

In some embodiments, the drive unit is designed for releasable coupling with the dosing unit. "releasable" is understood to have the same meaning as previously described in the context of the administration unit.

According to yet further aspects, the present disclosure relates to a portable infusion system for infusing a liquid drug into a body of a patient over an extended period of time. The infusion system may comprise a dosing unit and a drive unit as generally described before and further below in the context of exemplary embodiments.

In some embodiments of the portable infusion system, the valve driver and the valve driver coupler are in a disengaged state when the administration unit is coupled with the drive unit. For embodiments of this type, the engagement of the valve driver and the valve driver coupling only takes place in a state in which, after the coupling movement, the mechanical coupling between the drive unit and the dosing unit has been established. Thereby, the accuracy and alignment requirements for establishing the coupling are reduced to a large extent.

According to still further aspects, the present disclosure relates to a method for coupling a drug delivery unit and a method of driving a unit, as generally described before and further below in the context of exemplary embodiments. The method may comprise providing the drive unit and the dosing unit as structurally distinct units. The method may further comprise performing a coupling movement which causes the drive unit and the metering pump unit to enter an operable relative position, the coupling movement further causing the valve driver and the valve driver coupling to enter an operable relative position, wherein the valve driver and the valve driver coupling are in a non-engaged configuration during the coupling movement.

Drawings

Exemplary embodiments are discussed in more detail below with additional reference to the figures.

It should be noted, however, that in the following description, terms indicating a direction, position, or orientation, such as "left", "right", "up, down", "top", and "bottom", are intended merely to aid the reader's understanding and refer only to the accompanying drawings. It is not intended to imply any particular direction or orientation for the purposes of this application.

Fig. 1 shows the main components of a portable infusion system according to the present disclosure in a simplified functional view.

Fig. 2 shows an exemplary embodiment of a dosing unit in combination with an exemplary embodiment of a drive unit.

Fig. 3a, 3b illustrate an exemplary shutoff valve body with a valve actuator coupling attached in perspective view.

Fig. 4a, 4b, 4c illustrate the operation of the geneva gear as an exemplary embodiment of the step switch mechanism.

Fig. 5a, 5b show the internal structure of, and the operation of, a portion of an exemplary valve unit and an exemplary pump unit.

Fig. 6a, 6b show an exemplary portable infusion system.

Fig. 7a, 7b show the internal structure of, and the operation of, a portion of a further exemplary valve unit and a further exemplary pump unit.

Fig. 8 illustrates another example geneva gear.

Detailed Description

Fig. 1 shows a dosing unit 100 and a drive unit 200, as well as a liquid drug reservoir 300. It should be noted that only those structural and functional elements that are particularly relevant in view of the present disclosure are shown. Other units are also typically present, such as electronic control units, power supplies, user interfaces, etc.

The dosing unit 100 comprises a dosing pump unit 110 comprising a dosing cartridge having a bore and a piston (elements not separately numbered) as described above in the summary. In the proximal front wall of the administration cartridge, the aperture is arranged to couple to the fluid port of the pump port 127 a. The dosing unit further comprises a valve unit which can alternately be in a filling state 120b or a discharge state 120 a. During operation, the valve unit is repeatedly switched between these states. The reservoir 300 is fluidly coupled to the valve unit via the fill port 127b of the valve unit. The patient 900 is fluidly coupled to the valve unit via the fill port 127c, infusion site interface 890. It should be noted that the infusion site interface 890 is illustratively shown as being integral with an infusion line (e.g., a catheter). The dosing unit 100 further comprises a valve driver coupling 125 for switching the valve unit between the filling position 120b and the discharge position 120 a. Likewise, the dosing unit 100 comprises a pump driver coupling 115 for linearly moving a piston of the pump unit 110 inside the dosing cartridge.

With respect to the valve unit, it is further noted that fig. 1 only shows the state 120a, 120b in which either the fill port 127b or the drain port 127c is coupled to the pump port 127 a. In yet other intermediate states, all three ports 127a, 127b, 127c are closed, creating a fluid isolation.

The drive unit 200 includes a pump transmission 217 coupled to the pump drive coupling 215 and a valve transmission 227 coupled to the valve drive coupling 215.

In the following, reference is additionally made to fig. 2, which shows an exemplary dosing unit 100 and a corresponding exemplary drive unit 200, the dosing unit 100 and the drive unit 200 being part of the portable infusion system according to fig. 1. The driver unit 200 is typically designed as a long-life or durable module. Like other components of a portable infusion system, such as the user interface and control circuitry may be designed to have a useful life of months to years. The administration unit 100 is typically designed as a single-use module, which is typically temporarily used continuously for several days to (e.g.) 2 weeks and then discarded. Due to their different application times, the dosing unit 100 and the drive unit 200 are designed as releasable mechanisms and operable couplings as described previously. For mechanical coupling or mounting, the dosing unit 100 and the drive unit 200 are provided with a dosing unit mounting structure 195 and a drive unit mounting structure 295, respectively. Illustratively, the dosing unit mounting structure 195 is implemented as an elongated male structure having a T-shaped cross-section, and the drive unit mounting structure 295 is implemented as a corresponding elongated female structure having a T-shaped cross-section. The structure is designed to have a small clearance (optionally offset) sliding engagement. Optionally, a further locking element (not shown) may be provided. To couple the dosing unit 100 and the drive unit 200, the dosing unit 100 is moved linearly relative to the drive unit 200 in a direction opposite to arrow a such that the mounting structures 195, 295 are engaged. The uncoupling is performed by a corresponding linear reverse movement. In further embodiments, the mechanical coupling may be retained via a snap clamp, via a magnetic coupling, or the like, as will be described in the context of another embodiment below.

The direction indicated by arrow a is hereinafter referred to as "proximal" and the direction opposite arrow a is referred to as "distal".

The pump unit 110 and the valve unit 120 of the dosing unit 100 are exemplarily realized as a collinear design, wherein the piston displacement axis coincides with the valve rotation axis and is parallel to the arrow a, resulting in an elongated overall shape of the dosing unit 100. The valve unit 120 is disposed in a shape similar to the pump unit 110. The internal structure of both and the operation of the dosing unit 100 are further described below with additional reference to other figures.

At the proximal end of the valve unit 120, a valve driver coupling 125 is arranged rotatable about a valve rotation axis. The valve actuator coupling 125 is illustratively implemented as a sheave portion having three sectors.

The drive unit 200 comprises a pump transmission 217 and a valve transmission 227. The pump transmission 217 includes a pump actuator 217a and a pump gear 217b, and the valve transmission 227 includes a valve actuator 227a and a valve gear 227 b. Both the pump drive 217 and the valve drive 227 are designed for reciprocating operation.

Both the pump actuator 217a and the valve actuator 227a are illustratively embodied as conventional stepper motors. However, either of the two can also be implemented in different ways, for example as a standard dc motor, a brushless dc motor or a specially designed electromagnetic drive. Optional sensors may be present for control and/or feedback purposes, but are not required. For example, optional sensors may be provided for detecting the proximal and distal positions of the piston inside the bore of the drug delivery cartridge, which correspond to the minimum and maximum fill volumes of the drug delivery cartridge and/or linear position sensors may be provided for substantially continuously detecting the piston. Also, a sensor such as a contact or non-contact end switch may be present to detect whether the shutoff valve body of the valve unit 110 is in the filling position or the discharging position, respectively.

The pump gear 217b is designed as a reduction gear in the form of a conventional spur gear in combination with the spindle drive and the plunger 217c, so as to convert the rotary motion of the output shaft of the pump actuator 217a into a corresponding linear displacement motion of the plunger 217 in a direction parallel to the arrow a. In the coupled state of the dosing unit and the drive unit, the axis of the plunger 217c is coaxial with the bore of the dosing cartridge and the piston displacement axis. Attached to or part of plunger 217c is a pump drive 215 (not visible in fig. 2) which is designed to releasably couple with a pump drive coupling that is rigidly connected to or integral with a piston (not visible in fig. 2) of pump unit 110. The pump driver 215 and the pump driver coupling are designed as a push-pull coupling, such as a bayonet coupling, a snap-fit coupling, or the like. The reciprocating motion of the plunger 217c thereby causes a corresponding reciprocating piston motion in the proximal or distal direction, respectively.

The valve gear 277b is a reduction gear that is realized as a conventional gear with the valve driver 225 coupled to or integral with the output shaft of the valve gear 227 b. For the following design of the step-switch mechanism and the valve unit, the valve gear may be designed as a four-stage spur gear, for example. It should be noted, however, that alternative designs may be used for both the pump gear 217b and the valve gear 227b, such as planetary gears, worm gears, sprockets, or other types of traction drives.

Reference is additionally made below to fig. 3 and 4, respectively. Fig. 3a, 3b show two perspective views of the shut-off valve body 126 of the valve unit 120 together with a valve actuator coupling 125, the shut-off valve body 126 and the valve actuator coupling 125 being rigidly connected or integrally formed. The shut-off valve body 126 has a generally cylindrical shape and is designed for sealing and rotational sliding receipt in a corresponding bore of the valve housing. The shutoff valve body 126 has a central fluid passage 126a, which is implemented as a bolt hole and extends along the longitudinal axis of the shutoff valve body 126. The outlet of the central fluid passage 126a serves as a pump port 127 a. The shutoff valve body 126 also includes two radial passages 126b, 126c that are perpendicular and in fluid communication with the central passage 126 a. As will be explained in more detail below, the radial passages 126b, 126c are fluidly connected to a fill port 127b and a drain port 127 c. Illustratively, the radial channels 126b, 126c are arranged at a relative angle of 90 °. Other angles may be used.

The valve actuator coupling 125 is designed as a sheave portion. In a particular embodiment, the respective full sheave will have eight segments equally distributed around its circumference, while in fact three segments 125a for the valve actuator coupling 125 are implemented. The single segment 125a includes a concave circular peripheral surface 125b and a radial surface 125 d. The circular peripheral surface 125b and the radial surface 125d are connected via a small intermediate peripheral surface (not labeled). The radial surfaces 125d form radial engagement grooves 125c between adjacent segments 125 a.

Fig. 4 shows the design of the valve driver 225 and illustrates the interaction between the step switch mechanism, which is achieved by the combination of the valve driver 225 and the valve driver coupling 125. The valve driver 225 includes a body 225a, a center pin 225b and an eccentric engagement pin 225c, the individual components of the valve driver 225 being rigidly connected or integrally formed. The valve driver 225 is rigidly coupled to the output shaft of the valve gear 227b such that the center pin 225b and the output shaft are coaxial, such that when the output shaft rotates, the valve driver body 225a and the engagement pin 225c rotate about the center pin 225 b. As can be seen from fig. 4, the center pin 225b is actually a pin portion in which a section having a pointing engaging pin 225c is cut out. The diameter of the center pin 225b corresponds to the diameter of the circular peripheral surface 125, and the diameter of the engaging pin 225c corresponds to the width of the engaging groove 125c, so that substantially play-free sliding engagement is formed between the engaging pin 225c and the engaging groove 125c and between the center pin 225a and the circular peripheral surface 125 b.

Fig. 4a shows a configuration in which the valve unit 120 is in the filling position. In this state, the center pin 225b is in sliding rotational engagement with the circular circumferential surface 225 b. As long as the engagement pin 225c does not engage with the engagement groove 125c, any rotation of the valve driver 225 and in particular the retaining shaft 225b does not therefore cause any movement of the valve driver coupler 125. Via engagement, the valve actuator 125 is held and locked in its position.

To illustrate the operation of the step switch mechanism, assume that the valve actuator 225 is rotated clockwise, as indicated by the corresponding arrows in fig. 4a, 4b, 4 c. Fig. 4a shows the moment when the engaging pin 225c comes into engaging engagement with the engaging groove 125 c. Further rotation of the valve actuator 225 causes the engagement pin 225c to travel radially inward in the engagement slot 125c and, via sliding engagement with the slot wall, rotates the valve actuator coupling 125 in a counterclockwise direction with the shutoff valve body 126.

Fig. 4b shows a configuration in which the engaging pin 225c is at its radially innermost position in the engaging groove 125 c. Further clockwise rotation of the valve driver 225 will cause radially outward movement of the engagement pin 225c in the engagement slot 125c and further counterclockwise rotation of the valve driver coupler 125 until finally the engagement pin 225c leaves the engagement slot 125c, thereby ending the engagement between the engagement pin 225c and the engagement slot 125 c. Fig. 4c shows a configuration in which the engaging pin 225c is disengaged from the engaging groove 125c slightly later.

As can be seen in fig. 4a, 4b, 4c, the sheaves of the valve driver 125 are in engagement with at least one of the center pin 225b or the engaging pin 225c at all points in time. When the engagement pin 225b is in a position of engagement with the engagement groove 125c, the rotation of the valve driver coupler 225 is controlled by interaction with the engagement pin 225c via positive direction guiding. When the engagement pin 225c is in a position of non-interaction with the engagement slot 125c, the valve actuator coupling 125 is locked in place via engagement of the center pin 225b with the circular peripheral surface 125 b.

The configuration shown in fig. 4c is an intermediate configuration in which the valve unit is neither in the filling position nor in the discharge position, but rather there is no intermediate fluid coupling between the pump port 127a and either of the filling port 127a or the discharge port 127c, respectively. Further clockwise rotation of the plunger driver 225 will cause the foregoing sequence to be repeated, with the only difference being that the engagement pin 225c engages the other of the two slots 125 c. When the engagement pin 225c is disengaged from the second engagement groove 125c, the valve unit 110 is in the discharge position. Each full rotation of the valve driver 225 correspondingly causes rotation of the valve driver coupler 125, which corresponds to the angle between adjacent sheave type sections 125a or engagement grooves 125c, respectively.

For the exemplary design of the shutoff valve body shown in FIG. 3, the sequence of successive engaging and disengaging engagements between the engagement pin 225c and the two engagement slots 125c causes the valve actuator coupler 125 and the shutoff valve body 126 to rotate a total of 90 corresponding to the angle between the radial passages 126b, 126c, respectively. In a variant, the valve actuator coupling 125 can have more or fewer segments 125a, and the switching between the filling position and the discharge position can be effected via more than one intermediate step or without any intermediate step, as long as the total angle corresponds to the switching angle required according to the design of the shut-off valve body. For a typical design of a miniaturized ambulatory infusion system, the exemplary design shown is considered to be a good compromise taking into account factors such as friction (and thus energy consumption and design of the valve actuator), valve gear reduction ratio and overall size.

Switching the state of the valve unit back to the filling position is achieved in a similar way as a counter-clockwise rotation of the valve driver 225.

Advantageously, two pairs of stops (not shown separately) are provided that limit rotational movement between the valve actuator coupling 125 and the shutoff valve body 126 relative to the valve housing, such further movement of the valve actuator coupling 125 and the shutoff valve body 126 being prevented when the shutoff valve body is in the filling position or the discharge position, respectively. The rotational movement is therefore limited to an angular range between the filling position and the discharge position, respectively.

For such a design comprising a stop, a simple and effective control can be achieved when, for example, a stepper motor is used as the valve actuator. Since further movement of the valve actuator coupling 125 and the shut-off valve body 126 is not possible, further actuation of the stepper motor will cause a detectable loss of step when either the fill or drain position is reached. In this way, the filling position and the discharge position can be detected without the need for additional sensors.

The main advantage of using a step switch mechanism for the valve switch becomes clear from fig. 4a to 4c and the description given earlier.

As previously described, the rotational positions of the valve actuator coupler 125 and corresponding shut-off valve body 126 are well defined and locked for all rotational positions of the valve actuator 225 when the engagement pin 225c does not engage any of the engagement slots 125 c. This effectively maintains independence of the particular orientation of the valve actuator 225 and, in particular, the engagement pin 225 c. This is the case for the region indicated by the letter "B" in fig. 4, corresponding to a rotation angle of about 180 °, i.e. half of the full rotation of the valve driver 225. When switching between the filling position and the discharge position, respectively, it is therefore irrelevant in which exact rotational position the valve driver 225 starts its movement and after switching finally stops in which rotational position, as long as a complete sequence of engagement and disengagement between the engagement pin 225c and the engagement groove 125 is ensured. Thus, the accuracy requirements for the valve actuator and its control are significantly reduced.

The step switch mechanism is also advantageous with respect to the coupling of the dosing unit 100 and the drive unit 200. As previously mentioned, this process is performed on a routine basis by a user (such as a diabetic) who has no specialized mechanical abilities and in many cases has dyskinesias and/or visual impairments. As long as the engagement pin 225c is in a disengaged state, the only coupling between the valve driver 225 and the valve driver coupler 125 is provided by the sliding engagement between the center pin 225b and the circular peripheral surface 125 b. Thus, the coupling engagement between the dosing unit mounting structure 195 and the drive unit mounting structure 295 can be established by a simple translational movement of the dosing unit 100 relative to the drive unit 200 without requiring a specific orientation or rotational position of the valve driver 225. By coupling the dosing unit 100 to the drive unit 200 in this way, the correct operational position, and thus the operational coupling of the valve driver 225 with the valve driver coupling 125, is automatically established.

The foregoing advantages of the step switch mechanism can best be understood by comparison with alternative coupling forms that maintain the coupling via an angle, such as a pair of spur gears and a valve drive as a valve driver and valve driver coupling. Such coupling requires precise relative orientation of the coupling elements. Coupling via gears, such as spur gears, for example, requires that the teeth of one of the gears be aligned with the teeth of the other gear to establish proper meshing engagement.

The advantageous properties of a step switch mechanism for driving the movement of a valve are closely related to the general properties of a suitable step switch mechanism, with the driving or input element (valve driver) and the driven or output element (valve driver coupling) being in meshing engagement only temporarily for switching and over a portion of a full rotation of the driving or input element and otherwise disengaged. For a typical angle-maintaining gear, such as a spur gear, the drive or input member is in continuous meshing engagement with the driven or output member. Thus, other types of step-switch mechanisms as used in a wide variety of clock mechanisms and watches, for example, in film cameras and projectors, in pen-change mechanisms for chemical/medical analyzers or plotters, may be equally suitable for valve switching purposes.

The characteristics of the step-switch mechanism are also advantageous compared to alternative couplings that do not require special positioning, for example compared to a friction coupling via a pair of friction wheels, which are generally critical and are therefore subject to failure, for example due to unintentional friction reduction due to production and coupling tolerances, lubricants and wear.

However, coupling the administration unit 100 and the drive unit 200 in the manner described above requires a rotational position of the valve actuator coupling 125 in which either of the circular peripheral surfaces 125b is coaxially aligned with the center pin 225 b. For the embodiment shown, this requirement is met in both the filling position and the draining position (one of which is shown in fig. 4 a) and in the intermediate position shown in fig. 4c, respectively. Advantageously, for assembly, both in the filling position and in the discharge position, the shut-off valve body can be well defined by the stop as previously described. Since the dosing unit is typically a sterile disposable that is used for several days continuously and then discarded, only one coupling is performed for the dosing unit 100. Thus, the dosing unit may be provided by the manufacturer in a defined one of the filling position and the discharge position.

The internal structure of the dosing unit 100, in particular the pump unit 110 and the valve unit 120 and the operation thereof are received below with additional reference to fig. 5a, 5b, each of which shows a cross-sectional view of a part of the pump 110, as seen from the top of fig. 2 and the intersecting plane through the symmetry axes (piston displacement axis and valve rotation axis). Fig. 5a shows the filling state (valve body 126 in the filling position) and fig. 5b shows the draining state (valve body 126 in the draining position). However, for the exemplary design of the dosing unit 100, it has to be noted that the filling state and the discharge state are fluid equivalent and may thus be interchanged.

As can be seen from fig. 5a, 5b, the drug cartridge 112 illustratively has a central through hole of varying diameter along its central axis, and has a valve housing 127 sealingly disposed in a distal portion of the hole, and a piston 111 sealingly and slidably disposed from the valve housing 127 in the hole proximal side. During assembly, the valve unit is received distally from the central bore and the piston 111 is received proximally from the dosing cylinder 112, respectively. The proximal front surface of the piston 111 and the distal front surface of the valve housing 127 define, in combination, distal and proximal limiting surfaces of the metering chamber 113, respectively, and the pump port 127a is part of the proximal limiting surface.

As can be seen from fig. 5a, in the filling state the radial channel 126b is aligned with a filling port 127b, which, like the discharge port 127c, is formed by a radial fluid channel or bore in the valve housing 127. In this state, fill port 127b is correspondingly fluidly coupled with central passage 126 a. The other radial passages 126c are not aligned with the corresponding fluid passages or bores of the valve housing 127 and are thereby sealed closed via contact with the valve housing 127.

In the filling state, by displacing the piston 111 along the piston displacement axis in the distal direction opposite to arrow a, the dosing cartridge 112 can be filled accordingly with the liquid drug, thereby increasing and aspirating the liquid into the metering chamber 113. During this filling process, the valve unit 120 ensures fluid isolation of the exhaust port 127c, and thus of the infusion line 890.

In the discharge state shown in fig. 5b, the radial passage 126C is aligned with the discharge port 127C. In this state, the discharge port 127c is fluidly coupled with the central passage 126a, respectively. The other radial channels 126b are not aligned with the respective fluid channels of the valve housing 127 and are thereby sealed closed via contact with the valve housing 127.

In the discharge state, by displacing the piston 111 along the piston displacement axis in the proximal direction indicated by arrow a, the liquid in the metering chamber 113 can be discharged accordingly, thereby reducing and accordingly discharging the liquid from the metering chamber 113. During this expelling process, the valve ensures fluidic isolation at the fill port 127b, and thus the drug reservoir 300.

Fig. 6a, 6b illustrate an exemplary portable infusion system according to the present disclosure. The system includes a durable unit 400 and a disposable unit 500. Both units 400, 500 are shown oriented to correspond to the orientation during application, but are now in an unconnected state, e.g., prior to coupling. The coupling of the reusable unit 400 to the disposable unit 500 is achieved by linear movement of the reusable unit 400 relative to the disposable unit 500 in the direction indicated by arrow a. Fig. 6a and 6b differ only in that fig. 6a shows both units 400, 500 having an outer housing or casing, whereas the units 400, 500 in fig. 6b show no housing.

The reusable unit 400 includes a drive unit and may also include components such as a user interface, control circuitry, a communication interface, and the like. A circumferential seal 403 is provided at the interface to the disposable unit 500 to ensure water tightness or waterproof protection in the assembled state. Alternatively or additionally, a seal is provided at the disposable unit 500. In the following description, the same or corresponding elements as those of the foregoing embodiment are designated by the same reference numerals.

The disposable unit 400 comprises a dosing unit and a drug reservoir, which may be realized as a substantially flexible bag or pouch, such as for example a cylindrical rigid box, or a semi-rigid construction with rigid and soft or flexible elements. The same type of drug reservoir may be used in conjunction with a dosing unit as shown in figure 2.

The overall architecture of the administration portable infusion system and in particular of the administration unit and the drive unit corresponds to the design as shown in fig. 1. Furthermore, the design generally corresponds to the exemplary design shown in fig. 2 to 5. However, some aspects are implemented in a different manner, as will be described below.

In the embodiment of fig. 6, the drive unit is implemented as a mere rotary drive, and the pump driver 215 is a reciprocating rotary shaft. The pump driver 225 has a non-circular cross-section over at least a portion of its length, which may be achieved by a longitudinal female element (e.g., a slot) and/or a longitudinal protruding element (e.g., a wedge). The pump driver coupling (not shown) of the pump unit has a shape corresponding to the drive coupling 225 for engagement in the rotational direction and substantially frictionless or low-friction sliding engagement in the longitudinal direction. Thus, axial sliding engagement and rotational positive locking may be used to transmit drive torque from the pump driver 225 to a pump driver coupling having a corresponding cross-section. The pump drive coupling may be formed by an elongate axial element arranged away from the sealing piston and directed away from the metering chamber. The pump drive coupling may be rigidly coupled to the piston or integral with the piston. In order to convert the rotational movement of the pump driver 225 into a linear, or helical, movement of the piston, the distal part of the cartridge is provided with a thread, in particular an internal thread, the length of which corresponds at least to the total displacement distance of the plunger. A corresponding external thread is provided at least one portion of the pump drive coupling.

In contrast to the embodiment of fig. 2-5, in which the piston displacement axis coincides with the valve rotation axis, the valve rotation axis is parallel to arrow a' and perpendicular to the piston displacement axis. Accordingly, the valve housing 127 is also correspondingly perpendicular to the axis of the administration cartridge.

For coupling of the reusable unit 400 with the disposable unit 500, a snap clamp 405 is provided at the reusable unit. The snap clamp 405 is designed as a proximal split ring element and has a diameter to snap fit around the valve housing 127, which in this embodiment simultaneously serves as a drug delivery unit mounting structure. It should be understood that alternative mounting structures may be used, such as structures corresponding to that shown in fig. 2, as well as magnetic couplings and the like.

Corresponding to fig. 5a, 5b for the previous embodiment, the internal structure of the dosing unit according to the present exemplary embodiment 100, in particular the pump unit 110 and the valve unit 120, and the operation of the dosing unit, is explained below with additional reference to fig. 7a, 7 b. In the embodiment of fig. 7, the shutoff valve body 126 has only two radial passages 126b and 126, but no central passage. The radial passages 126b and 126c are designed as through holes that are axially displaced along the axis of symmetry of the shutoff valve body 126 and arranged at an exemplary angle of 90 °. Two pump ports 127a are provided, one of which is aligned with the radial passage 126b in the filling state (fig. 7 a) and the other of which is aligned with the radial passage 126c in the discharge state (fig. 7 b). Likewise, two corresponding apertures (not numbered) are provided in the substantially closed proximal front face 112a of the drug delivery cartridge 112, which are aligned with the pump port 127 a.

The fill port 127b and the exhaust port 127c are arranged parallel to the piston displacement axis and perpendicular to the valve rotation axis in this embodiment. For this purpose, a design is given which forms a straight fluid connection of the filling port 127b or the discharge port 127c, respectively, to the metering chamber 113 via the radial channel 126b or 126c, respectively.

Fig. 8 shows an arrangement of a step switch mechanism with a valve driver 225 and a valve driver coupling 115, which is exemplary of a state of non-meshing engagement.

Reference numerals

100	Dosing unit
		110	Pump unit
111	Piston
		112	Medicine feeding tube
112a	Proximal anterior
		113	Metering chamber
115	Pump drive coupling
		120	Valve unit
120a	Valves (discharge position)
		120b	Valves (filling position)
125	Valve actuator coupling
		125a	Sheave type section
125b	Round peripheral surface
		125c	Engagement groove
125d	Radial surface
		126	Shutoff valve body
126a	Central passage
		126b, c	Radial channel
127a	Pump port
		127b	Filling port
127c	Discharge port
		195	Drug delivery unit mounting structure
200	Drive unit
		215	Pump drive
217	Pump drive
		217a	Pump actuator
217b	Pump gear
		217c	Plunger piston
225	Valve actuator
		225a	Valve actuator body
225b	Center pin
		225c	Engagement pin
227	Valve drive
		227a	Valve actuator
227b	Valve gear
		295	Drive unit mounting structure
300	Drug reservoir
		400	Reusable unit
403	Sealing element
		405	Buckle clamp
500	Disposable unit
		890	Infusion line with infusion site interface
900	Patient's health

Claims (14)

1. A dosing unit (100) for a portable infusion system, comprising:

-a metering pump unit (110) comprising a dosing cartridge (112) and a piston (111), said piston (111) being arranged inside said dosing cartridge (112) in sealing sliding engagement;

-a valve unit (120), the valve unit (120) having: a filling port (127 b) designed to fluidly couple with a liquid drug reservoir (300); an outlet port (127 c), the outlet port (127 c) designed for fluid coupling with an infusion site interface (890); and a shut-off valve body (126), the shut-off valve body (126) being movable between a filling position in which the filling port (127 b) is fluidly coupled with the administration cartridge (112) and an alternate discharge position in which the administration cartridge (112) is fluidly coupled with the discharge port (127 c);

-a valve actuator coupling (125), the valve actuator coupling (125) being coupled to or integral with the shut-off valve body and being an output element of a step switch mechanism.

2. Dosing unit (100) according to claim 1, wherein the valve driver coupling (125) comprises a star wheel or a star wheel portion, a sheave or a sheave portion.

3. Dosing unit (100) according to any of the preceding claims, wherein the shut-off valve body (126) is designed as a substantially cylindrical body.

4. Dosing unit (100) according to any of the preceding claims, wherein the shut-off valve body (126) is made of a hard material, in particular a hard plastic, and the shut-off valve body contact surface of the valve housing (127) is made of a soft material, in particular a rubber or a thermoplastic elastomer.

5. Dosing unit (100) according to any of the preceding claims, wherein the shut-off valve body (126) is designed for a rotational movement around a valve rotation axis.

6. Dosing unit (100) according to claim 5, wherein the valve rotation axis is parallel or perpendicular to a piston displacement axis of the pump unit (110).

7. The dosing unit (100) according to any of the preceding claims, wherein the valve driver coupling (125) comprises an engagement groove (125 c), the engagement groove (125 c) being for engagement with an engagement pin (225 c) of a valve driver (225) as a driving element of a step switch mechanism.

8. The dosing unit (100) according to claim 7, wherein the dosing unit (100) is designed to be releasably coupled with a drive unit (200).

9. A drive unit (200), the drive unit (200) comprising:

-a pump transmission (217), the pump transmission (217) comprising a pump actuator (217 a) and a pump driver (215) coupled to the pump actuator (217 a), the pump driver (215) being designed to be coupled to a piston of a metering pump unit (110) to transmit a pump driving force and/or a pump driving torque from the pump actuator (217 a) to the piston (111) of the pump unit (110);

-a valve transmission (227), the valve transmission (227) comprising a valve actuator (227 a) and a valve driver (225) coupled to the valve actuator (227 a), the valve driver (225) being designed to be coupled to a valve driver coupling (125) of a valve unit (120) for transmitting a valve switching force and/or a valve switching torque from the valve actuator (227 a) to the valve unit (120),

wherein the valve driver (225) is a drive element of a step switch mechanism.

10. The drive unit (200) of claim 9, wherein the valve driver (225) comprises an engagement pin (225 c) for engaging with the valve driver coupling (125).

11. The drive unit (200) according to claim 9 or 10, wherein the drive unit (200) is designed to be releasably coupled with the dosing unit (100).

12. A portable infusion system for infusing a liquid drug into a body of a patient over an extended period of time, the infusion system comprising a dosing unit (100) according to claim 8 and a drive unit (200) according to claim 11.

13. The ambulatory infusion system according to claim 12, wherein the valve driver (225) and the valve driver coupler (125) are in a non-engaged state when the dosing unit (100) is coupled with the drive unit (200).

14. A method for coupling a dosing unit (100) according to any of claims 1 to 8 and a drive unit (200) according to any of claims 9 to 11, the method comprising:

-providing the drive unit (200) and the dosing unit (100) as structurally different units;

-performing a coupling movement causing the drive unit (200) and the metering pump unit (110) to enter an operable relative position, the coupling movement further causing the valve driver (225) and the valve driver coupler (125) to enter an operable relative position, wherein the valve driver (225) and the valve driver coupler (125) are in a non-engaged configuration during the coupling movement.