Patent Application
20240285859
The invention relates to a single dose injection device for expelling one dose of a predetermined fixed volume of a liquid drug. More particular the invention relates to an injection device which is pre-filled by the manufacturer of the injection device by use of a pre-filled cartridge and designed for manually expelling one single fixed dose of a predetermined volume of liquid drug from the encapsulated cartridge and preferably by one stroke of an axially movable piston rod moving translational inside the cartridge.
The invention further relates to a method of assembling such single dose injection device.
Syringes used to expel the full content of a cartridge in one stroke has been known for decades. An example of such syringe is disclosed in U.S. Pat. No. 2,753,867. Here an exchangeable cartridge containing a liquid drug is inserted into a tubular housing structure and a threaded nut element guiding a piston rod is screwed into the housing structure to secure the cartridge axially relatively to the housing structure. The content of the cartridge is expelled by moving a plunger in the distal direction inside the cartridge. The axial movement of the plunger is performed by the user manually pushing the piston rod in the distal direction. The full injectable volume contained in the cartridge is expelled as one single dose through a double pointed needle assembly attached to a needle interface provided distally on the housing structure. The forward movement of the piston rod is first stopped when the plunger inside the cartridge reaches the distal neck part of the cartridge hence the proximal stop is not fixed but depend on the physical shape of the cartridge and the resiliency of the plunger. The volume expelled as the plunger moves through the cartridge hence very much depend on the physical tolerances of the cartridge and the tolerances in the filling process.
A different example of an automatic spring-operated injection device wherein a cartridge can be used is provided in EP 3,628,352. In this example, the cartridge used has a difference in the fill volume due to tolerances and therefore also a different axial position of the plunger prior to use. Therefore, once the cartridge is mounted in the housing structure, a gap can exist between the plunger and the piston rod. When injecting, the piston rod may move in this free space without actually moving the plunger inside the cartridge which means that the axial movement of the piston rod is not converted directly into a similar movement of the plunger which causes the volume of the expelled dose to vary from cartridge to cartridge depending on the tolerances determining the position of the plunger in the individual cartridge. To compensate for this, the automatic firing mechanism can be adjusted in its relative axial position during assembly of the injection device.
A more traditional manual multi-dose insulin injection device is disclosed in US 2018/0140,776. In this injection device a piston rod is rotated in a threaded nut element to move helically in the distal direction during injection to thereby press out an individually set dose. During assembly of this injection device it is possible to axially position the nut element in relation to the housing.
It is henceforth an object of the present invention to provide a solution wherein the volume expelled when expelling the single fixed dose is not dependent on the above explained tolerances.
This is preferably done by moving the piston rod forward a predetermined travel distance in one single stroke of the piston rod and to make the physical position of this travel distance in relation to the housing structure and thus the cartridge embedded in the housing structure variable for each individual injection device.
The invention is further defined in claim 1. Advantageous embodiments are defined in the dependent claims. Accordingly, in one aspect of the present invention, a single dose injection device for delivering a predetermined volume of a liquid drug, comprises:
Further, according to the invention, the piston rod structure and the nut element are provided with engagement means for releasable securing the piston rod structure to the nut element in a start position of the piston rod structure in which start position, the piston rod structure abuts the plunger, at least in use,
The travel distance of the piston rod is thus the distance the piston rod is movable from its start position to its stop position. However, it is important that the travel distance is transformed one-to-one to plunger movement all though the plunger has a variable position inside each individual cartridge. This is achieved by guiding the piston rod in a nut element which is adjustable in relation to the housing structure. It is hence possible, for each individual injection device to adjust the physical position of the travel distance. The position of the travel distance is preferably adjusted such that the piston rod structure (including the piston rod foot) abuts the plunger in the start position of the piston rod.
Preferably, the piston rod foot abut the plunger in a situation of use. Due to temperature variations, the abutment is not necessarily fully established when the injection device is in storage. However, as a starting position, when in use, the piston rod foot abuts the plunger.
The actual physical position of the start position is preferably determined by the physical design of the nut element. However, the distance between the start position and the stop position is decisive for the length the piston rod moves during ejection and the position of this distance, the travel distance, is adjustable for each individual injection device.
All though the travel distance is a fixed distance, the position of the travel distance in relation to the housing structure is, as herein explained, adjustable. As the cartridge is fixed to the housing structure, the position of the travel distance in relation to the cartridge and to the plunger inside the cartridge are also adjustable.
The nut element and hence the position of the travel distance are thus individually adjustable for each individual injection device and the position of the travel distance can be adjusted to accommodate the individual position of the plunger inside each cartridge.
The piston rod is coupled to the nut element in a position defining the start position but in a releasable coupling such that the piston rod can be moved out of the start position to start the ejection. Further, the stop position for the piston rod is defined by a stop surface on the piston rod. In the stop position this stop surface engages and abuts against the nut element.
The distance between the start position and the stop position is the travel distance that the piston rod travels in relation to the nut element and to the housing structure including the cartridge during one single ejection and could also be referred to as the length of the stroke of the piston rod.
The piston rod structure is releasable secured to the nut element by releasable engagement means. These releasable engagement means secures the piston rod in a releasable position from which the piston rod can be released simply by applying a pressure on to the proximal end of the piston rod. In one example, the engaging means between the piston rod and the nut element comprises a number of radial arms provided on either the piston rod or the nut element engaging the other of the piston rod or the nut member.
In a preferred example, the radial arms are provided on the piston rod whereas the nut element is provided with an angled front which is engaged by the radial arms when the piston rod is in its start position. The angled front is preferably sloped in the proximal position to better prevent the piston rod from movement in the proximal direction when assembled.
Alternatively, the engagement means between the piston rod and the nut element comprises a number of further radial arms provided on the piston rod frictionally engaging a recessed inner surface on the nut element in the start position of the piston rod.
In a different example the engaging means between the piston rod and the nut element comprises a number of radial gripping teeth provided on either the piston rod or the nut element engaging the other of the piston rod or the nut member. In this example, the radial gripping teeth are preferably provided on the piston rod and the nut element is provided with an angled surface which is engaged by the radial gripping teeth when the piston rod is in its start position. The gripping teeth can have any desired size and shape.
The physical location of the start position is determined by the physical design of the nut element which in one example is provided with a proximal flange which defines the start position for the piston rod and which proximal flange engages with the stop means on the piston rod in the stop position.
The adjustment of the nut element in relation to the housing structure can be envisage in a number of different ways. It could be a strictly linear adjustment, or it could be a helical adjustment. In a preferred example, the nut element is preferably axially adjusted in relation to the housing structure in a threaded connection between the nut element and the housing structure.
Following the adjustment, the nut element can be secured to the housing structure in a number of different ways. In one example, the nut element and the housing structure could be welded together e.g. by laser welding. In a different example a ratchet interface could be used which specifically could be a one-way ratchet.
In one example the housing structure is provided with a thread on an inner surface engaging a corresponding thread on an outer surface of the nut element. These threads can be either full threads or segments of threads. In one example, the pitch of the threads are configured such that the nut element is moved in the distal direction when the nut element is rotated anti clockwise in the thread connection to thereby obtain the adjusted position.
In order to maintain the nut element in the adjusted position, the flanges of the thread can be provided with axial friction knobs. These knobs can have any desired size and shape necessary to hold the nut element from rotation in the opposite direction and away from the adjusted position. As an alternative to, or as an addition to the axial friction knobs a ratchet interface can be provided. Such ratchet interface could be formed as one or more flexible teeth operating in a toothed rib such that rotation is allowed in both rotational directions. To further prevent the nut element from unscrewing the ratchet interface can be a one-way ratchet interface provided between the nut element and the housing structure. Such a one-way ratchet interface can operate together with the described friction knobs but can also operate without the friction knobs.
Such one-way ratchet can in one example be provided as a flexible ratchet carrier provided on one of the nut element or the housing structure and an axial rib structure provided the other of the nut element and the housing structure. The flexible ratchet carrier thus engages with the axial rib structure to form the one-way ratchet. For this purpose, the ratchet carrier can be provided with one or more teeth for the actual engagement. The flexible ratchet carrier is preferably formed as an arm or as a beam construction. The nut element and the housing structure are thus irreversible connected in the assembled state. However, the flexible ratchet carrier could as mentioned be provided as a ratchet interface allowing rotation in both directions.
In a second aspect of the present invention, a method of assembling a single dose injection is provided. The method comprises a single dose injection device as defined in the claims wherein the method comprises the step of individually adjusting the axial position of the nut element for each individual injection device during assembly to thereby adjust the axial position of the travel distance of the piston rod structure relatively to the housing structure to an adjusted position wherein the piston rod structure abuts the plunger.
Hence, for each individual injection device the position of the nut element is adjusted to an adjusted position wherein the piston rod structure i.e. the piston rod or the piston rod foot abuts the plunger inside the cartridge such that the stroke of the piston rod is transferred to an identical linear movement of the plunger. By having this adjustability of the nut element and thus the travel distance of the piston rod it can be prevented that some of the piston rod movement is done in the air-gap space occasionally existing between the plunger and the piston rod structure due to the variable position of the plunger in the individual cartridge.
In a third aspect the invention relates to a plurality of single dose injection devices for delivering a predetermined volume of a liquid drug according to any of the apparatus claims and wherein each single dose injection device in the plurality has been individually assembled and adjusted according to the method claim.
An “injection pen” or “pen for injection” is typically an injection apparatus having an oblong or elongated shape somewhat like a pen for writing. Although such pens usually have a tubular cross-section, they could easily have a different cross-section such as triangular, rectangular or square or any variation around these geometries.
The term “Needle Cannula” is used to describe the actual conduit performing the penetration of the skin during injection. A needle cannula is usually made from a metallic material such as e.g. stainless steel and connected to a hub to form a complete injection needle also often referred to as a “needle assembly”. A needle cannula could however also be made from a polymeric material or a glass material. The hub also carries the connecting means for connecting the needle assembly to an injection apparatus and is usually moulded from a suitable thermoplastic material. The “connection means” could as examples be a luer coupling, a bayonet coupling, a threaded connection or any combination thereof.
The term “Needle unit” is used to describe one single needle assembly carried in a container. Such container usually has a closed distal end and an open proximal end which is sealed by a removable seal. The interior of such container is usually sterile such that the needle assembly is ready to use. Needle units specially designed for pen injection systems are defined in ISO standard No. 11608, part 2, and are often referred to as “pen needles”. Pen needles are usually double pointed having a front-end for penetrating through the skin of a user and a back-end for penetrating into the cartridge containing the drug such that liquid communication is established during injection.
As used herein, the term “Liquid drug” is meant to encompass any drug-containing flowable medicine capable of being passed through a delivery means such as a hollow needle cannula in a controlled manner, such as a liquid, solution, gel or fine suspension. Representative drugs include pharmaceuticals such as peptides, proteins (e.g. insulin, insulin analogues and C-peptide), and hormones, biologically derived or active agents, hormonal and gene-based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form.
“Cartridge” is the term used to describe the container actually containing the drug which are often referred to as the primary packing. Cartridges are usually made from glass but could also be moulded from a suitable polymer. A cartridge or ampoule is preferably sealed at one end by a pierceable membrane referred to as the “septum” which can be pierced e.g. by the non-patient end of a needle cannula. Such septum is usually self-sealing which means that the opening created during penetration seals automatically by the inherent resiliency once the needle cannula is removed from the septum. The opposite end of the cartridge is typically closed by a movable “plunger” which is a piston-like element made from rubber or a suitable polymer. The plunger is during use slidable moved inside the cartridge preferably in a distal direction. The space between the pierceable membrane and the movable plunger holds the liquid drug which is pressed out as the plunger decreased the volume of the space holding the liquid drug. The cartridges used for both pre-filled injection devices and for durable injections devices are typically factory filled by the manufacturer with a predetermined volume of a liquid drug. A large number of the cartridges currently available contains either 1.5 ml or 3 ml of liquid drug.
Since a cartridge usually has a narrower distal neck portion into which the plunger cannot be moved not all of the liquid drug contained inside the cartridge can actually be expelled. The term “initial quantum” or “substantially used” therefore refers to the injectable content contained in the cartridge and thus not necessarily to the entire content.
By the term “Pre-filled injection device” is meant an injection device in which the cartridge containing the liquid drug is permanently embedded in the injection device such that it cannot be removed without permanent destruction of the injection device. Once the pre-filled amount of liquid drug in the cartridge is used, the user normally discards the entire injection device. Usually the cartridge which has been filled by the manufacturer with a specific amount of liquid drug is secured in a cartridge holder which is then permanently connected in a housing structure such that the cartridge cannot be exchanged.
This is in opposition to a “Durable injection device” in which the user can himself change the cartridge containing the liquid drug whenever it is empty. Pre-filled injection devices are usually sold in packages containing more than one injection device whereas durable injection devices are usually sold one at a time. When using pre-filled injection devices an average user might require as many as 50 to 100 injection devices per year whereas when using durable injection devices one single injection device could last for several years, however, the average user would require 50 to 100 new cartridges per year.
All references, including publications, patent applications, and patents, cited herein are incorporated by reference in their entirety and to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
All headings and sub-headings are used herein for convenience only and should not be constructed as limiting the invention in any way.
The use of any and all examples, or exemplary language (e.g. such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability, and/or enforceability of such patent documents.
This invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.
The invention will be explained more fully below in connection with a preferred embodiment and with reference to the drawings in which:
The figures are schematic and simplified for clarity, and they just show details, which are essential to the understanding of the invention, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts.
When in the following terms as “upper” and “lower”, “right” and “left”, “horizontal” and “vertical”, “clockwise” and “counter-clockwise” or similar relative expressions are used, these only refer to the appended figures and not necessarily to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as their relative dimensions are intended to serve illustrative purposes only.
In that context it may be convenient to define that the term “distal end” in the appended figures is meant to refer to the end of the injection device supporting the injection needle, whereas the term “proximal end” is meant to refer to the opposite end carrying the injection button as indicated on
When referring to clock-wise and anti or counter clock-wise in the following examples it is understood that the injection device is viewed from a position distal to the injection device. Clock-wise is thus a rotation following the arms on an ordinary clock and counter clock-wise is a rotation in the opposite direction.
To explain the various movements which take place in the injection device described in the example, the following terminology are used throughout the following detailed description;
“Translational movement” is meant to be a strictly linear movement without any rotation.
“Rotational movement” is any movement of rotation around a centre which centre can be a centre point i.e. in one planar or a centre axis i.e. having a longitudinal extension.
“Axial movement” means any movement in an axial direction. Such movement can be a strictly translational movement or include a rotational movement which thus makes it a “Helical movement” as this is meant to be an axial movement combined with a rotational movement.
“Telescopic” is meant to cover the situation in which a movable element moves out from, and/or into, a base element. The telescopic movement can be either translational or include a rotation thus making the telescopic movement helical.
As seen in
The needle assembly 20 used is a standard pen needle as disclosed in
In one example, the needle cannula 21 could be a gauge 29 (G29) needle cannula and the length of the distal part of the needle cannula 21 being inserted into the skin could be 4 mm when measured from the needle hub 22 to the sharp distal point 24. The distal part of the needle cannula 21 could further have a conical shape.
Inside the housing structure 1, the cartridge 10 is positioned as disclosed in
Distally the septum 11 is secured to the cartridge 10 by a metal cap 15 which is bended around a neck 16 of the cartridge 10 as it is generally know from cartridges.
The housing structure 1 disclosed in
A different alternative of fixating the cartridge 10 to the housing structure 1 is disclosed in
During injection, the plunger 12 is moved in the distal direction inside the cartridge 10 by a piston rod 50 which in the disclosed examples distally are provided with a separate piston rod foot 45 to better distribute the forces onto the plunger 12. The piston rod foot 45 could in one example be moulded integral with the piston rod 50.
The piston rod 50 engages, and is guided by, a nut element 60 which is axially adjustable relatively to the housing structure 1 as will be explained.
As best seen in
Besides the crush ribs 7 provided on the inner surface of the housing structure 1, a number of longitudinal ribs 8 for supporting the cartridge 10 are also provided. Further, the housing structure 1 has its inner surface provided with an inner thread 5 for securing the nut element 60 as will be explained. Distally to the inner thread 5, a toothing comprising a number of axial ribs 6 are provided which engages with the nut element 60.
The nut element 60 is disclosed in
In one embodiment disclosed in
Distally, the nut element 60 is provided with a number of flexible ratchet carriers 66 which flexes in the radial direction and engages the axial ribs 6 in the housing structure 1 such that the nut element 60 can only be rotated relatively to the housing structure 1 in one rotational direction. These flexible ratchet carriers 66 can be provided as flexible arms as disclosed in
However, the flexible ratchet carriers 66 need not be executed as a one-way ratchet but can also be shaped such that rotation is possible in both rotational directions.
On the outer surface, the nut element 60 is provided with a number of outwardly pointing support flanges 61 which lie against the inner surface of the housing structure 1. As best seen in
The nut element 60 is further provided with a number of radial openings 62 which can be aligned with the most proximal end of the cartridge 10 when mounted as best seen in
Further, the inner surface of the nut element 60 is provided with a number of longitudinal support ribs which supports the cartridge 10.
The injection button 40 disclosed in
Further, the piston rod 50 disclosed is provided with a first set 53 of flexible radial arms and a second set 54 of flexible radial arms. The second set 54 of flexible radial arms is on an outer surface provided with flat surfaces 55 which in one example each distally terminates in radial gripping teeth 56. This is best seen in the enlarged view in
When the piston rod 50 is mounted in the nut element 60 as seen in
Alternatively, the piston rod 50 can be moulded without the radial gripping teeth 56. In such embodiment, the proximal end of the first set 53 of radial arms engage the angled front 64 to define the start position of the piston rod 50. Hence, distally the piston rod 50, preferably with the piston rod foot 45, abuts the plunger 12 inside the cartridge 10 and the proximal end of the first set 53 of the radial arms engages the angled front 64 on the nut element 60 thus defining the start position of the piston rod 50. Since temperature changes in the liquid drug can alter the position of the plunger 12 during storage, a little clearance between the proximal end of the first set 53 of arms and the angled front 64 of the nut element 60 is allowed for without changing the fact that the piston rod 50 (and/or foot 45) abuts the plunger 12 in the adjusted start position as will be explained.
In the latter example disclosed in
In the example disclosed in
The two sets of flexible radial arms 53, 54 can comprise any number of flexible arms in each set. However, in the disclosed example two flexible arms are provided in each set of radial arms 53, 54. As indicated in the figures, the flexible radial arms 53, 54 are flexible in a direction allowing only movement of the piston rod 50 toward the distal end of the housing structure 1. Once the piston rod 50 is mounted in the nut element 60 as disclosed in
In
The start position as physically shown in
The travel distance (TD) thus expresses the distance the piston rod 50 is able to move from its start position to its stop position. This length of the travel distance (TD) thus being a fixed distance, however, the physical position of the travel distance (TD) can be changed by adjusting the position of the nut element 60 relatively to the housing structure 1 in dependency of the position of the plunger 12 inside the individually filled cartridge 10.
When filling liquid drug into the individual cartridge 10 different tolerances apply. There are tolerances on the volume of liquid drug filled into the cartridge 10 from the filling line and there are tolerances on the physical dimensions on the cartridge 10. Filling of a cartridge 10 is usually done by filling the liquid drug into the cartridge 10 from the distal end of the cartridge 10. The plunger 12 is thus positioned in the distal part of the cartridge 10 prior to filling and during filling the plunger 12 moves proximally to the position wherein the correct volume of drug has been filled into the cartridge 10. Once filled, the distal end of the cartridge is sealed by the septum 11. Hence, due to the various tolerances, the end position of the plunger 12 when filled will vary from cartridge 10 to cartridge 10.
Further, as cartridges 10 are usually formed from glass the physical tolerances are relatively large. The different tolerances result in a slightly different axial position of the plunger 12 inside the individual cartridge 10 after filling the liquid drug into the cartridge 10.
After the cartridge 10 is filled with liquid drug, the cartridge 10 is pushed into the housing structure 1 in the distal direction such that the metal bend 15 on the cartridge 10 are press fitted into the crush ribs 7 in the housing structure 1 as disclosed in
When the cartridge 10 is placed and secured in the housing structure 1, the position of the plunger 12 is electronical measured by a computerized sensor system such that the exact position of the plunger 12 inside each individual cartridge 10 is registered.
When the position of the plunger 12 is measured, the nut element 60 is screwed into the thread 5 inside the housing structure 1 to a position wherein the piston rod 50 (when mounted) or preferably the piston rod foot 45 engages the plunger 12. The axial position of the nut element 60 is thus individually adjustable to an adjusted position during assembly of the injection device. The adjusted position being the position wherein the piston rod 50 (and/or foot 45) abuts the plunger 50 which is also the start position for the piston rod movement.
When the nut element 60 has been rotated to its adjusted position, the piston rod 50 is pushed into the nut element 60 to a position wherein the first set 53 or radial arms or the gripping arms 56 engages the angled front 64. This engagement defines the start position of the travel distance (TD). As best seen in
Alternatively, the piston rod 50 can first be positioned in the releasable secured position in nut element 60 before the nut element 60 is screwed into the housing structure 1 and the nut element 60 could be rotated until the piston rod 50 (or the piston rod foot 45) abuts the plunger 12 inside the cartridge 10.
In the disclosed example, the nut element 60 is provided with a number of ratchet carriers 66 which engages the axial ribs 6 inside the housing structure 1 such that the nut element 60 can only be rotated in one rotational direction in the thread connection between the thread 5 inside the housing structure 1 and the thread segments 65 provided on the nut element 60.
In one example the pitch of the thread 5 in the housing structure 1 and the pitch of the thread segments 65 on the nut element 60 can be e.g. 2 mm such that the nut element 60 is moved 2 mm in the distal direction per revolution. In such construction when e.g. 40 axial ribs 6 are provided inside the housing structure 1, the nut element 60 can be moved forward in increments of 0.05 mm (2 mm advancement to 40 ribs per revolution).
The allowed rotational direction being the one which moves the nut element 60 in the distal direction. When the nut element 60 has reached its adjusted position, it is thus not possible to rotate the nut element 60 in the proximal direction, as the ratchet interface 6, 66 only allows for rotation in one direction. In an alternative example, the nut element 60 can be irreversible secured to the housing structure 1 in the adjusted position preferably by welding the nut element 60 to the housing structure 1 e.g. by using laser welding. For this purpose, the housing structure 1 can be provided with a transparent area, an opening or the like such that the energy from a laser beam can be delivered to the area wherein the nut element 60 and the housing structure 1 has a physical point of contact.
Once the nut element 60 is positioned in the adjusted position, the piston rod 50 is inserted as disclosed in
The starting point of the piston rod movement could also be defined by the frictional engagement of the further radial arms 58 and the recessed inner surface 63 as disclosed in
When the nut element 60 is in the adjusted position and the piston rod 50 is mounted in the start position, the distal end of the piston rod 50 preferably has physical contact with the proximal backside of the plunger 12 such that there is no physical distance between the piston rod 50 and the plunger 12. However, some slack is allowed due to temperature variations.
In the disclosed example a separate piston rod foot 45 is provided which can be inserted into the cartridge 10 prior to inserting the piston rod 50. When such piston rod foot 45 is used, the physical contact is between the piston rod foot 45 and the plunger 12.
When the piston rod 50 has been inserted as disclosed in
Once the injection device is assembled as disclosed in
When injecting, the user applies a pressure onto the injection button 40. This is indicated by the arrow “P” in
The axial movement of the piston rod 50 from the start position to the stop position as indicated on
The volume expelled during injection is determined by the first position of the plunger 12 prior to injection as disclosed in
When the piston rod 50 (or the piston rod foot 45) initially abuts the plunger 12 in the first position, the travel distance (TD) of the piston rod 50 will be transformed to a similar movement of the plunger 12 inside the cartridge 10 hence the length of the travel distance
(TD) i.e. the distance between the start position and the stop position of the piston rod 50 and the length between the first position and the second position of the plunger 12 will be the same.
Some preferred embodiments have been shown in the foregoing, but it should be stressed that the invention is not limited to these but may be embodied in other ways within the subject matter defined in the following claims. The important issue reflected in the claims is to avoid that an air gap exist between the plunger and the piston rod foot after assembly, such that a part of the travel distance (TD) is consumed by this air gap and hence not fully transferred to plunger movement.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21180787.0 | Jun 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/066818 | 6/21/2022 | WO |
