Patent Description:
In the disclosure of the present invention reference is mostly made to the treatment of Human Growth Hormone, HGH, however, this is only an exemplary use of the auto-injector.

The most common type of auto-injection devices adapted to receive a drug filled cartridge (also termed reservoir or container) and expel a dose therefrom are generally elongated e.g. pen-formed for being hold in a user's one hand and utilizes a so-called cartridge holder adapted to receive and mount a cartridge in the device. Correspondingly, most pen-formed drug delivery devices comprises a generally cylindrical cartridge holder for receiving and holding a generally cylindrical drug-filled cartridge in a mounted position, the cartridge comprising a proximally facing and axially displaceable piston, and a main body with a housing in which a drug expelling mechanism is arranged, the mechanism comprising an axially displaceable piston rod adapted to engage the piston of a mounted cartridge to thereby expel a dose of drug from the cartridge. Between the cartridge holder and the main body coupling means is provided allowing a user to remove the cartridge holder from the main body and reattach it when a used cartridge has been exchanged with a new cartridge. The cartridge is inserted in the cartridge holder by axial movement through a proximal opening. Conventionally, the coupling means are in the form of a threaded connection or a bayonet coupling.

It is conventionally only insufficiently addressed that there is a need for devices that are easier and more intuitive to use.

<CIT> discloses a drug delivery system comprising a cartridge and a front-loaded cartridge holder adapted to axially receive and hold a cartridge in a loaded position. The cartridge comprises first coupling means arranged at the distal portion, and the cartridge holder comprises second coupling means arranged at the distal portion, wherein the first and second coupling means are configured to engage each other to thereby axially secure a cartridge mounted in the cartridge holder.

However, this front-loaded drug delivery system is cumbersome to use since it requires that a user uses two hands for the operation of loading the drug delivery system with a cartridge since one hand is needed to hold the device and another is needed to insert and rotate the cartridge. For at least some groups of users this may prevent own use or make own use very cumbersome.

<CIT> discloses a medical delivery system comprising a container which is adapted to be fastened to a dosing assembly. One of the container and the dosing assembly comprises a rotatable element adapted to cooperate with the other one of the container and the dosing assembly, so as to lock/fasten the container to the dosing assembly. <CIT>, <CIT> and <CIT> describe medicament delivery systems comprising also releasable rotational locking mechanisms.

There is provided an auto injector for administering injection of a medicament from a cartridge containing the medicament, the auto injector comprising:.

wherein at the first angle, movement of the cartridge assembly is allowed and at the second angle, movement of the cartridge assembly is restricted in the receiving direction at least from moving beyond a predefined longitudinal position.

Thereby the ejector rest portion and the ejector lock support member in combination may form a stop that is disengaged at the first angle and engaged at the second angle.

Thus, it is appreciated that, at the second angle, the ejector lock by its turning effectively introduces a stop, by its support member receiving the rest portion. The stop prevents further movement of the rest portion beyond the support member in the receiving direction, if the rest portion is not otherwise prevented from landing on the support member. Thus, the stop contributes to prevent the cartridge from movement beyond a stop position, relative to the housing, in the receiving direction.

At least when the needle of the cartridge assembly penetrates a being's skin a force is transferred from the needle to the cartridge and works to push the cartridge backwards in the receiving direction against the stop when it is engaged. The stop at least contributes to maintaining the position of the cartridge since otherwise precise dose administering may be obstructed.

When the ejector, by means of the stop, sits at the stop position, its ejector support face supports that an end portion of the cartridge or cartridge assembly rests thereon to prevent unintended movement in the receiving direction.

The auto injector enables convenient front-loading of a cartridge accommodated in a cartridge assembly. Since the needle on the cartridge assembly may be protected by a needle cover reliably attached to the cartridge assembly, there is no increased risk of being injured by the needle while loading the auto injector with a cartridge accommodated in a cartridge assembly.

The auto injector enables convenient front-loading by: overcoming the spring-loaded bias when the cartridge meets the support face of the ejector, guiding the cartridge retention members from the passage to a position where the cartridge is prevented from moving out of the cartridge receiver, and turning the ejector lock to prevent movement beyond the stop in the receiving direction such that the cartridge maintains its position in the housing when a pressure on the needle in the receiving direction is at least partially transferred to the cartridge. It is important that the cartridge maintains its position since otherwise precise dose administering is obstructed.

It is appreciated that various distances should be dimensioned such that the support face of the ejector lock abuts the rest portion of the ejector when the cartridge sits in the retention position. Thereby the cartridge is locked or is in a locked position being prevented both from a forward movement and a backward movement, wherein the backward movement is the same as the receiving direction. The cartridge is locked when the stop is engaged i.e. when the ejector lock is at the second angle, whereas the cartridge is unlocked when the stop is disengaged i.e. when the ejector lock is at the first angle.

In some aspects the ejector lock support member extends axially from a wall of the ejector lock, e.g. in the form of a pin, to support the ejector at a transversely extending ejector rest portion. In some aspects the ejector lock support member extends transversely along a rim or edge of the ejector lock to support the ejector at transversely extending ejector rest portion or at an axially extending rest portion.

In some aspects one or more of the ejector lock support portion, the ejector rest portion and the ejector slot are recessed into the ejector lock or the ejector.

It is appreciated that the ejector lock is supported e.g. in a bearing that allows the lock to turn or be turned, at least a fraction of a revolution, while preventing a longitudinal movement.

In some embodiments, the ejector comprises an ejector rod with an ejector support face; wherein the ejector rod has an ejector rod bore to form a longitudinal passage, and wherein the ejector support face is arranged at one end of the ejector rod and has a disc shape or an annular shape.

Thereby the disc shape or annular shape may form the support for the cartridge to rest thereon all around its end portion periphery. An aperture of the bore is located in a centre portion of the ejector abutment face. The bore gives room for a plunger that at least over some displacements thereof may move, independently of the ejector, to move a first stopper of the cartridge to expel at least a portion of the medicament from the cartridge.

In some embodiments, the ejector rod comprises an ejector collar arranged about the ejector support face. The ejector collar may have an inner diameter which is larger than an outer diameter of an end portion of the cartridge or cartridge assembly such that when the end portion of the cartridge or cartridge assembly abuts the ejector support face, the collar accommodates the end portion of the cartridge or cartridge assembly in a centralised position relative to the ejector rod.

Thereby the cartridge or cartridge assembly can be guided to abut robustly on the ejector support face. In some aspects the ejector collar has an inner chamfer face which improves guiding of the cartridge or cartridge assembly towards the ejector support face.

In some embodiments, the ejector comprises an ejector rod configured with one or more ejector cut-outs to form one or more ejector cogs between the ejector cut-outs; and wherein the ejector lock is configured with one or more ejector lock cogs between one or more ejector lock cut-outs, respectively.

Thereby the one or more ejector cogs may abut with the one or more ejector lock cogs to form the stop when engaged. The stop is engaged by aligning the cogs of the ejector and the ejector lock. Turning of the ejector lock at least a portion of a revolution about the longitudinal axis may disengage the stop whereby the ejector cogs can be accumulated in the ejector lock cut-outs. In this way the cogs and the cut-outs form complementary cogs and cut-outs.

The one or more cogs of the ejector rod and the one or more complementary cut-outs of the ejector lock are arranged at angular ranges about the longitudinal axis such that a cog can be accommodated in its entirety or partially by a complementary cut-out. A cog may extend over e.g. <NUM> degrees and a complementary cut-out may extend over <NUM> degrees plus an angular range to allow a clearance when the ejector rod and thus the cog moves in the longitudinal direction in or out of the cut-out of the ejector lock.

The angles at which cut-outs, cogs and complementary cogs and cut-outs are located implicitly define the first angular position where the ejector lock and ejector rod mutually are angularly positioned to allow movement of the cartridge assembly in the receiving direction, and the second angular position where the ejector lock and ejector rod mutually are angularly positioned to restrict movement of the cartridge assembly in the receiving direction at least restricted from moving beyond a predefined longitudinal position.

In the second angular positon, at least one cog of the ejector rod abuts end-to-end at least one cog of the ejector lock; whereas in the first angular position, the at least one cog of the ejector rod is accommodated in a complementary cut-out.

The ejector cogs have end portions denoted an ejector rest portion and the ejector lock cogs have end portions denoted an ejector lock support portion. The ejector lock support portion supports the ejector rest portion when the stop is engaged.

Thus the cogs have respective end portions which abut one another when the stop is engaged. Cut-outs of the ejector rod and cut-outs of the ejector lock have respective bottom portions. The bottom portions may extend between side portions separating cogs and cut-outs.

At a longitudinal position of the ejector rod where the cogs abut one another, the ejector defines by its length relative to the ejector lock at which position the cartridge or cartridge assembly is restricted from further movement by means of the stop in the receiving direction. The ejector may be suspended by a resilient member to move in the opposite direction of the receiving direction, in which case the cogs of the ejector rod travels away from the cogs of the ejector lock.

As mentioned above the cartridge or cartridge assembly may be supported at a disc shape or annular shape, which in some embodiments is configured with a surrounding collar.

In some aspects the ejector rod has four cogs and four cut-outs and the ejector lock has four complementary cogs and four complementary cut-outs. This gives a good trade-off between the amount of rotation needed to turn the ejector rod and the ejector lock relative to each other from a securely locked position to an open position and mechanical robustness of the cogs.

In some aspects the cogs and cut-outs have an even angular size, e.g. <NUM> degrees or <NUM> degrees - in both cases minus an angular range to allow a clearance between a cog and a cut-out.

In some embodiments one or more of the cut-outs and the cogs have a substantially rectangular shape.

Thus, the one or more cut-outs, such as ejector cut-outs and/or ejector lock cut-outs have edges orthogonal to the longitudinal axis and edges along the longitudinal axis. Due to the edges along the longitudinal axis a good engagement for retaining a relative angular position between the ejector rod and the lock is obtainable at least when the stop is engaged.

In some aspects thereof the ejector cut-outs accommodate ejector lock cogs and ejector lock cut-outs accommodate ejector cogs in a complementary manner such that spaces are substantially filled out between cogs to resemble a cylindrical object. However, an angular clearance is typically needed between cogs to allow sufficiently low friction of a longitudinal movement and to allow for variations occurring during manufacture of the ejector and ejector lock.

In some aspects the cut-outs and the cogs comprise a triangular portion, an arc of a circle or another polygon or curve.

In some embodiments the one or more cut-outs and the one or more cogs comprise a portion that is inclined relative to the longitudinal axis and relative to an axis orthogonal to the longitudinal axis.

The portion that is inclined relative to the longitudinal axis may be one or more of an end portion of one or more cogs, a bottom portion of one or more cut-outs, and a side portion of one or more cogs or cut-outs.

As an aspect of securing smooth longitudinal movement any angle between a side portion and a bottom portion should be <NUM> degrees or greater and any angle between a side portion and an end portion should be <NUM> degrees or greater. Thereby it should be prevented that a nose or overhang is formed, behind which cogs could be stuck in unfortunate positons.

In some of the aspects, wherein a portion is inclined, the ejector cut-outs may accommodate ejector lock cogs and ejector lock cut-outs may accommodate ejector cogs in a complementary manner such that spaces are substantially filled out between cogs to resemble a cylindrical object. However, an angular clearance is typically needed between cogs to allow sufficient low friction of a longitudinal movement.

In some embodiments, ejector cogs and lock cogs comprise an end portion that is inclined relative to the longitudinal axis at an angle of less than <NUM> degrees or less than <NUM> degrees or less than <NUM> degrees relative to the orthogonal of the longitudinal axis.

The inclined end portions may contribute such that when the stop is engaged by turning of the lock, further turning of the lock causes a longitudinally tightening force acting on the ejector and transmitted though the ejector to the cartridge and/or cartridge assembly. In this way it may be possible to at least substantially remove clearances that occur due to manufacture variations.

The end portions of lock cogs and end portions of ejector cogs are inclined substantially at the same angle such that the end portions are mutually parallel. In some aspects the bottom portions of the cut-outs may be inclined by substantially the same angle. Thereby the cogs fit into the cut-outs.

Thus the cogs have respective end portions which abut one another when the stop is engaged. Due to the inclined end portions and possibly manufacture variations, a desired tightening force or clearance reduction may occur at an angular position of the lock where the ejector cogs and the lock cogs do not align centre-to-centre, but somewhat offset therefrom.

Thereby it may be possible to tighten up the cartridge in a more precise longitudinal position as well as ensuring that cartridge length dimension tolerances do not result in or at least risk expelling fluid from the cartridge when pressing the needle towards the skin. Thus the risk of unintended rearward travel of the cartridge due to short cartridge length in combination with a too retracted lock position is reduced. Had the cartridge not been prevented from such unintended rearward travel, a plunger rod in contact with the stopper could possibly press out medicament too soon before the needle is properly inserted in the skin of the patient and thus the full dose would not be administered to the patient.

In some embodiments, the ejector comprises an ejector rod configured with a substantially cylindrical portion with one or more chamfers about the longitudinal axis to form a rotational asymmetric end portion; and wherein the ejector lock is configured with one or more complementary chamfer cuts to form a complementary rotational asymmetric end portion.

In some aspects the chamfer is positioned such that the end portion extends over a portion that is substantially orthogonal to the longitudinal axis. The end portion that extends over a portion that is substantially orthogonal to the longitudinal axis may extend over less than <NUM> degrees e.g. over less than <NUM> degrees or less than <NUM> degrees.

In some embodiments, the auto injector comprises a plunger rod; wherein the ejector comprises an ejector rod which is spring-loaded by a spring ejector member; wherein the plunger rod and the bore are configured for longitudinal relative movement.

Thereby the ejector and the plunger rod can be closely integrated. Also, the plunger rod may be moved along the longitudinal axis, at least over some distance, without bringing the ejector rod along and vice versa.

The ejector rod may comprise a cylindrical object through which the bore extends; wherein the above-mentioned cut-outs and cogs are located at one end of the cylindrical object and wherein the above-mentioned disc shape or annular shape is arranged at the other end.

In some aspects, the bore through the ejector rod and an exterior face of the plunger rod are configured with coupling means and complementary coupling means, respectively, that retains a relative angular position and allows a relative longitudinal movement. There may be formed a track extending along a straight line along the longitudinal axis on the wall of the bore that engages with a groove in the plunger rod, and/or vice versa. Thereby longitudinal movement is allowed while angular retention is provided.

In some embodiments, the plunger rod comprises an inner plunger rod part and an outer plunger rod part; wherein the inner plunger rod part and the outer plunger rod part are coupled by a thread; wherein the inner plunger part is retained in a bearing allowing rotation of the inner plunger part while preventing a longitudinal movement; and wherein the outer plunger rod part is retained in an angular position relative to the housing.

Thereby the outer plunger part may be actuated to move in the longitudinal direction by rotation of the inner plunger rod part. The outer plunger part may be configured to move a first stopper of the cartridge to expel at least a portion of the medicament from the cartridge.

In some aspects the inner plunger rod part is rotational driven by a drive module, which may comprise a motor and one or more of transmission and gearing to couple the motor to the inner plunger rod. The inner plunger rod part may comprise a spindle portion that engages with an inner thread in the outer plunger rod part.

In some aspects the outer plunger rod part is retained in the angular position relative to the housing in that there is formed a longitudinally extending plunger rod groove in the wall of the outer plunger rod; wherein the plunger rod groove engages with a longitudinally extending bead or track on the inner wall of the ejector rod bore. This configuration allows displacement, at least over some distances, of the outer plunger rod relative to the ejector rod and vice versa while retaining a relative angular position between them.

In some embodiments, the auto injector comprises an angle retaining slot and an angle retaining guide configured to engage with each other and arranged on or in the cartridge receiver or a member rigidly coupled to the cartridge receiver and at the ejector rod.

Thereby the ejector rod is suspended for angular retention with the cartridge receiver and for longitudinal displacement at least over some distances.

In some aspects the angle retaining slot is configured in a member that accommodates the ejector rod and plunger rod when in a retracted position; the angle retaining slot may sit next to the ejector rod when it is retracted. The member, which may accommodate a motor coupled to drive the inner plunger rod, may comprise a collar providing a curb or seat for a spring inflicting the spring-load on the ejector. The angle retaining guide is then arranged on the ejector rod.

In some embodiments the ejector lock comprises an ejector lock guide pin configured to engage with a plunger rod track provided in the plunger rod, such that longitudinal movement of the plunger rod, at least over a predefined range, inflicts a turning of the ejector lock about the longitudinal axis.

Thereby it is possible to drive the auto injector with a single motor which at some displacements of the plunger rod inflicts turning of the lock and at other displacements of the plunger rod inflicts expel of a dose of medicament from the cartridge. At least the plunger rod track may be configured such that the plunger rod turns the ejector lock and disengages the stop at retracted positions where the plunger rod is at a position at a distance from the cartridge. The plunger rod track may be configured such that stop is engaged at advanced positions of the plunger rod, when at least it abuts or presses on a stopper of the cartridge.

In some embodiments movement of the plunger rod in the receiving direction, at least over a range of longitudinal positions, inflicts a turning of the ejector lock to the first angular position. Thereby the stop is disengaged at retracted positions of the plunger rod.

In some embodiments, the ejector lock is configured with an ejector lock bore to accept at least an end portion of the outer plunger rod and an ejector lock guide pin that extends inwardly from a wall of the ejector lock bore; wherein the outer plunger rod is configured with a plunger rod track that engages with the ejector lock guide pin and extends from a plunger rod distal rim towards the cartridge assembly opening; wherein the plunger rod track has at least one track portion that leads the ejector lock guide pin from a first angle to a second angle that are angularly spaced apart to turn the ejector lock from the first angular position to the second angular position.

Thereby rotation of the inner plunger rod part may bring about a longitudinal movement of the outer plunger rod part to at least engage with the cartridge at least at some longitudinal positions of the outer plunger rod part and to inflict a rotation of the ejector lock at other longitudinal positions of the outer plunger rod part to either lock or unlock the ejector member rod.

In some aspects the track is configured such that it rotates the ejector lock via the guide pin to a position that unlocks the ejector rod when the outer plunger rod is at an extreme longitudinal position away from the cartridge receiver opening. The track may rotate the ejector lock via the guide pin to another position that locks the ejector rod when the outer plunger rod is at a less extreme longitudinal position away from the cartridge receiver opening. Thus, as the outer plunger rod member is moved from an extreme position in the direction opposite of insertion, the ejector lock moves from a position where the ejector is unlocked to a position where the ejector is locked.

It is appreciated that the angular position of the guide pin relative to the cogs and cut-outs and the angular position of the outer plunger rod relative to the ejector rod are synchronized such that the rotation inflicted to the ejector lock by the track via the guide pin is angularly positioned to allow the cogs to abut end-to-end in second angular position, and the cogs to be accommodated in the cut-outs in the first angular position. It is appreciated that in the first angular position, the ejector is unlocked by the ejector lock and in the second angular position the ejector is locked by the ejector lock.

In some aspects the length of the ejector member and ejector lock when adjoining each other such that the cogs are accommodated by the complementary cut-outs.

The ejector lock is arranged e.g. in a bearing that allows the lock to turn or be turned, at least a fraction of a revolution, while preventing a longitudinal movement.

In some aspects the at least one track portion that leads the guide pin from the first angle to the second angle is inclined about <NUM>-<NUM> degrees relative to the longitudinal axis.

In some aspects the at least one track portion that leads the guide pin from the first angle to the second angle is an intermediate portion that continues from a first longitudinally extending track portion and continues to second longitudinally extending track portion. In some aspects thereof the first track portion is wider than the second track portion. In some aspects, wherein the first track portion is wider than the second track portion, the first track portion may comprise an inclined guide face or chicane that guides the guide pin into the intermediate track portion. The first track portion may extend from the first angle to the second angle. The inclined guide face may be inclined about <NUM>-<NUM> degrees relative to the longitudinal axis. The track is generally configured with track portions that extends longitudinally or at steep inclination angles; such that in the latter case, a turn is smoothly inflicted the guide pin typically by inclination angles not closer to the orthogonal of the longitudinal direction than about <NUM> degrees. Thereby, at least for that reason, the guide pin will not be stuck in the track.

In some aspects the track has a width at least at a portion of the track which is equal to a dimension of the guide pin plus a clearance, wherein the dimension of the guide pin may be its diameter or diameter or a circumferential circle or a width of the pin. The clearance may be smaller than <NUM>% or smaller than <NUM>% or smaller than <NUM>% the dimension of the guide pin.

The first, entry, portion of the plunger rod track may be wider than the intermediate and second portion of the plunger rod track. Thereby the ejector lock guide pin may be received and guided into the track at wider angles. This may prevent the ejector lock guide pin from unintentionally obstructing movement of the plunger rod.

In some embodiments, the plunger rod track is configured as a recess that extends from the plunger rod distal rim of the outer plunger rod. The depth of the recess matches a length of the guide pin such that they engage sufficiently for turning the ejector lock.

In some embodiments the ejector lock is coupled to a resilient member that biases the ejector lock towards the second angular position. Thereby more retracted positions of the plunger rod are required to disengage the ejector lock. This is particularly useful when an entry portion of the plunger rod track accepts the ejector lock guide pin at wider angles.

In some embodiments the auto injector comprises a drive module with a motor and one or more of transmission and gearing to couple the motor to the inner plunger rod. The drive module may be power suppled from one or more of a battery and a power supply. The drive module may be controlled via a microprocessor programmed to control the plunger rod via the drive module in response to user activated controls such as push-buttons.

A more detailed description follows below with reference to the drawing, in which:.

The term 'user' refers to a human being using the auto injector for self-administering a medicament. In this respect the user may also be designated a 'patient'. Thus, one use case of the auto injector is self-administration of a medicament. The auto injector is described with this use case in mind. However, in another use case an assistant, e.g. a nurse or home carer, may operate the auto injector to administer the medicament into the patient. The latter use case is also enabled by the present disclosure of the auto injector. The user may use the auto injector in connection with his or hers daily activities.

<FIG> shows an auto injector. The auto injector <NUM> may be configured for administering a medicament. The auto injector <NUM> may be an electronic auto injector.

The auto injector <NUM> comprises a housing <NUM>. The auto injector <NUM> comprises a cartridge receiver <NUM>. The cartridge receiver is configured to receive a cartridge and/or a cartridge assembly comprising a cartridge. The cartridge may contain the medicament.

The cartridge receiver <NUM> has a cartridge receiver opening <NUM>. The cartridge receiver <NUM> is configured to receive the cartridge and/or the cartridge assembly through the cartridge receiver opening <NUM> in a cartridge receiving direction <NUM> along a longitudinal axis, L.

The auto injector <NUM> may comprise a user interface <NUM>, as illustrated. The auto injector <NUM> comprises a trigger member, such as the contact member <NUM>. The contact member <NUM> may be configured to be pressed against an injection site on a patient's skin. The contact member <NUM> may be movable in the cartridge receiving direction <NUM>, relative to the housing, if pressed against the injection site. The contact member <NUM> may be part of the user interface <NUM>.

The user interface <NUM> comprises a first input member <NUM>, e.g. a button. The first input member <NUM> may provide for a user input from a user. For example, the first input member <NUM> may be used for receiving a push from a user to proceed to a next step.

The user interface <NUM> comprises a first output member <NUM> as illustrated, e.g. a plurality of LEDs. The first output member <NUM> may provide for a user output to a user. The user interface <NUM> may comprise a second output member (not shown), e.g. a speaker. The second output member may be configured to provide audible output to the user. For example, the first output member <NUM> and/or the second output member may be used to indicate a step in the procedure to the user and/or to indicate an error message.

The auto injector <NUM> may comprise a cover (not shown) to protect the auto injector from dirt and filth when not in use.

<FIG> shows the auto injector with a cartridge. The system <NUM> comprises an auto injector <NUM>, as described in relation to <FIG>, and an exemplary cartridge <NUM> received in the cartridge receiver <NUM> by front loading. The cartridge <NUM> is shown with a needle cover <NUM>. The needle cover <NUM> extends out of the contact member <NUM> to allow removal of the needle cover <NUM> from the cartridge <NUM>.

By front loading is understood that at least the cartridge <NUM> is received with its needle end pointing out of the cartridge receiver opening <NUM>. When the cartridge is being inserted and especially when it is fully inserted or almost fully inserted, the cartridge or cartridge assembly may be substantially covered by the housing or the contact member <NUM>. Especially in this situation the needle cover <NUM> serves as a protective means that makes it possible for a user at least to press on the needle cover <NUM> or a tip thereof to fully insert the cartridge without being injured by the needle. When the cartridge is fully inserted and sits in a retention position it is possible to detach the needle cover such that the auto injector is ready for use to inject the medicament or a portion thereof contained in the cartridge. After use, i.e. when a dose of medicament has been injected, the needle cover is attached such that the needle cover again serves as a protective means that makes it possible for a user at least to press on the needle cover <NUM> or a tip thereof to remove the cartridge without being injured by the needle.

<FIG> shows a cartridge, such as a cartridge <NUM> being configured to be received in the cartridge receiver of an auto injector, such as the auto injector described in relation to the preceding figures.

The cartridge <NUM> comprises a cartridge compartment <NUM>. The cartridge compartment <NUM> may be configured for containing a medicament. The cartridge <NUM> has a first end <NUM> and a second end <NUM>. The cartridge <NUM> comprises a cartridge outlet <NUM> at the first cartridge end <NUM>. The cartridge may be configured to expel medicament through the cartridge outlet <NUM>. The cartridge outlet <NUM> may be sealed by a needle penetrable sealing. The sealing may be made from rubber and optionally comprise a piercing which enables the needle to penetrate the sealing, while sealing the medicament when the needle is not penetrating the sealing.

The cartridge comprises a first stopper <NUM> movable inside the cartridge compartment, e.g. in a first stopper direction <NUM>, e.g. towards the first cartridge end. For example, the medicament may be expelled through the cartridge outlet <NUM> upon movement of the first stopper <NUM> in the first stopper direction. The cartridge comprises a cartridge back face <NUM> at the second cartridge end. The cartridge back face <NUM> comprises a cartridge back end opening for providing access to the first stopper <NUM> for a plunger rod.

As illustrated, the cartridge <NUM> may be a dual chamber cartridge. The cartridge comprises a second stopper <NUM> movable inside the cartridge compartment <NUM>, e.g. in the first stopper direction <NUM>, e.g. towards the first cartridge end. The cartridge compartment <NUM> comprises a first cartridge sub-compartment <NUM> and a second cartridge sub-compartment <NUM>. The first cartridge sub-compartment <NUM> is between the first stopper <NUM> and the second stopper <NUM>. The second cartridge sub-compartment <NUM> is between the second stopper <NUM> and the cartridge outlet <NUM>. The cartridge comprises a bypass section <NUM> for providing fluid communication between the first cartridge sub-compartment and the second cartridge sub-compartment. The bypass section <NUM> provides fluid communication between the first cartridge sub-compartment and the second cartridge sub-compartment when the second stopper <NUM> is positioned in the bypass section <NUM>.

The first cartridge sub-compartment <NUM> contains a first medicament component <NUM> of the medicament <NUM>. The first medicament component <NUM> may be a liquid as illustrated. The second cartridge sub-compartment <NUM> contains a second medicament component <NUM> of the medicament <NUM>. The second medicament component <NUM> may be a powder composition. By positioning of the second stopper <NUM> within the bypass section <NUM>, the first medicament component <NUM> may be transmitted into the second cartridge sub-compartment <NUM> via the bypass section <NUM>, thereby mixing the first medicament component <NUM> and the second medicament component <NUM> to achieve the combined medicament <NUM>.

The cartridge <NUM> may generally have a cylindrical form. However, the bypass section <NUM> may form a protrusion from the generally cylindrical form.

<FIG> shows a cartridge holder with a cartridge. The cartridge holder <NUM> accommodates at least a portion of the cartridge <NUM> by frictional coupling. Like the cartridge <NUM>, the cartridge holder <NUM> may have a generally cylindrical form. An inner diameter of the cartridge holder <NUM> matches with an outer diameter of the cartridge. The cartridge holder may be made from a plastics material, whereas the cartridge typically is made from glass or a glass-like material; the cartridge may also be made from a plastics material.

As shown, the cartridge holder <NUM> accommodates the first cartridge end <NUM> of the cartridge. The cartridge holder <NUM> has a cartridge holder slot <NUM> which accommodates the bypass section <NUM> which is shown in <FIG> as a protruding member. The cartridge holder introduces coupling options to the cartridge in the form of a needle assembly coupling portion <NUM>, which as shown may take the form of a threading, and cartridge retention members <NUM>. The cartridge retention members <NUM> may take the form of protrusions that extends from the generally cylindrical form of the cartridge holder <NUM>. The cartridge retention members <NUM> may be located at or close to the rim of the cartridge holder at the opposite end of the cartridge assembly outlet opening <NUM>. In some embodiments the cartridge retention members <NUM> are arranged at a greater distance from the rim than shown.

The needle assembly coupling portion <NUM> makes it possible to couple the cartridge <NUM>, via the cartridge holder <NUM>, to a needle assembly as will be described in greater detail below.

<FIG> shows a cross section of a cartridge assembly with a needle assembly. Note that the cartridge <NUM> is shown without stoppers, but with the bypass section <NUM>.

The needle assembly <NUM> is coupled to the cartridge holder by a respective needle assembly coupling portion <NUM> and cartridge holder coupling portion <NUM> of the needle assembly and the cartridge holder. The coupling portions <NUM> and <NUM> may be in the form of threading.

The needle assembly <NUM> comprises a needle hub <NUM> that holds a needle <NUM>. The needle hub <NUM> may have a bore at its one end into which the needle extends and on sidewalls of which the needle assembly coupling portion <NUM> is arranged. The needle assembly <NUM> also comprises a needle cover <NUM> that may be coupled by frictional coupling to the needle hub.

<FIG> shows a cartridge receiver. The cartridge receiver <NUM> has a cartridge receiver compartment <NUM> configured to receive a cartridge assembly <NUM> through a cartridge receiver opening <NUM>. The cartridge receiver compartment <NUM> has a first section, at a first distance from the cartridge receiver opening <NUM>, with inwardly extending first guide members <NUM> that are spaced apart to form passages <NUM> between the inwardly extending first guide members <NUM>. The inwardly extending first guide members <NUM> form a first bore accepting the cartridge assembly <NUM> when inserted through the cartridge receiver opening <NUM>. The diameter of the bore is slightly larger than an outer diameter of the cartridge assembly <NUM> excluding the cartridge retention members <NUM>, but is smaller than the diameter of a circle circumscribing the cross section of the cartridge assembly <NUM> and the cartridge retention members <NUM>. The cartridge retention members <NUM> can thereby not pass a first guide member <NUM> unless the cartridge is turned about the longitudinal axis, L, such that the cartridge retention members pass through the passages <NUM>.

The cartridge receiver compartment <NUM> has an additional second section <NUM>, with an annular shape, at a second distance, more remote than the first distance, from the cartridge receiver opening <NUM>. The second section <NUM> has second guide members <NUM>. The second guide members <NUM> are arranged with inclined faces and at angular positions about the longitudinal axis such that a cartridge retention member <NUM> having passed the passage <NUM> next to a first guide member <NUM> in the receiving direction is guided behind the first guide member <NUM> by an angular turning about the longitudinal axis, L.

The second guide members <NUM> form a second bore also accepting the cartridge assembly <NUM>. The diameter of the second bore is substantially the same as the first bore, i.e. slightly larger than an outer diameter of the cartridge assembly <NUM> excluding the cartridge retention members <NUM>, but smaller than the diameter of a circle circumscribing the cross section of the cartridge assembly <NUM> and the cartridge retention members <NUM>. The cartridge retention members <NUM> can thereby not pass a second guide member <NUM>. So when a cartridge retention member <NUM> lands on the second guide members <NUM>, a turning of the cartridge assembly is inflicted.

The cartridge receiver <NUM> comprises flanges and coupling means such as opening <NUM> for coupling to other components of the auto injector (not shown). The cartridge receiver <NUM> also comprises a base <NUM> comprising a bore <NUM> for a spring (not shown) providing a spring-bias to the contact member <NUM>, which may be guided by a guide rod (not shown) accommodated in a bore <NUM>.

<FIG> shows the cartridge receiver with an ejector. In this view the cartridge receiver <NUM> is shown in a different perspective than in <FIG>. It is shown that an ejector <NUM> extends out of the cartridge receiver <NUM> from the other end of the cartridge receiver than the cartridge receiver opening end.

<FIG> shows a detailed view of the first section and the second section of the cartridge receiver compartment. In this view, portions of the first section <NUM> and the second section <NUM> are cut up along the longitudinal axis and fold out from their generally annular shape. The functional aspects of the first section and the second section are described in connection with <FIG> below. The dashed line at the bottom of <FIG> indicates the orientation of the longitudinal axis, L, and points in the receiving direction, which in this depiction is to the left. The cartridge receiver opening (not shown in this depiction) is located towards the right hand side. Thus, the first section <NUM> is arranged closer to the cartridge receiver opening than the second section <NUM>. The curved dashed line to the left, DR, indicates a direction of rotation about the longitudinal axis when the first section <NUM> and the second section <NUM> are arranged as annular members.

The first section <NUM> comprises first guide members <NUM> and the second section <NUM> comprises second guide members <NUM>.

The first guide members <NUM> extends over first guide member angles <NUM> and are spaced apart to form passages <NUM> at passage angles <NUM> between the first guide members <NUM>.

The second guide members <NUM> have first faces <NUM> and second faces <NUM> (cf. The first faces and the second faces are arranged alternately and separated by first riser portions <NUM>. The first faces are, in the exemplary embodiment of <FIG>, divided into sections <NUM> and <NUM> separated by a second riser portion <NUM>. Similarly, the second faces are, in the exemplary embodiment of <FIG>, divided into sections <NUM> and <NUM> separated by second riser portions <NUM>. The first faces are inclined about a radial axis to the longitudinal axis and angularly arranged to extend at least partly over passage angles <NUM> and first guide member angles <NUM>.

The first guide members <NUM> have a first guide face that faces the cartridge receiver opening, i.e. to the right hand side in this depiction, and forms a convex pointing shape with an apex directed towards the cartridge receiver opening.

The first guide members <NUM> also have a face that faces away from the cartridge receiver opening, i.e. to the left hand side in this depiction, and forms a concave shape with a slope portion <NUM>, at slope angles <NUM>, leading towards a retention portion <NUM> at or about a bottom portion of the concave shape at a retention angle <NUM>. The slope portion <NUM> is inclined relative to the longitudinal axis and relative to the orthogonal thereto such that a turning of the cartridge is inflicted when a cartridge retention member <NUM> is pushed towards the slope portion <NUM> by a spring-loaded ejector <NUM>. The turning brings the cartridge retention member <NUM> to the retention portion <NUM>. To limit further turning of the cartridge assembly, a retention face <NUM> is provided substantially along the longitudinal axis.

Further, the first guide members <NUM> also have an eject face <NUM> with a slope that is inclined relative to the longitudinal axis and relative to the orthogonal thereto such that a turning of the cartridge is inflicted when a cartridge retention member <NUM> is pushed towards the slope portion <NUM> by a spring-loaded ejector <NUM>.

<FIG> shows an inbound journey and an outbound journey of a cartridge retention member. The cartridge retention member <NUM> is depicted as an object with a circular cross section, e.g. in the form of a guide pin, but it may have other forms. The cartridge retention member <NUM> is shown at different positions indexed by a numeral following the reference numeral; for instance <NUM>-<NUM> indicates the position of the cartridge retention member <NUM> at position <NUM>.

Dashed lines indicate a so-called inbound journey of the cartridge retention member <NUM> and dashed-dotted lines indicate a so-called outbound journey.

To avoid cluttering the figure, not all reference numerals are inserted, however the reference numerals used in <FIG> apply to <FIG> for like-shaped elements.

When a cartridge assembly <NUM> with a cartridge retention member <NUM> is inserted, starting out in the receiving direction, the cartridge retention member <NUM> follows an inbound journey. As examples the inbound journey may start at position <NUM> or position <NUM> or position <NUM> at different angles. At position <NUM> the cartridge retention member <NUM> may pass straight into the passage <NUM> to position <NUM>, whereas at position <NUM> the first guide member <NUM> inflicts a turning of the cartridge retention member, starting at position <NUM>, where the cartridge retention member lands on the first guide member and continuing by the inflicted turning and longitudinal movement such that it is guided into the passage <NUM>. Also at position <NUM> on the other side of the passage <NUM>, a first guide member <NUM> inflicts a turning of the cartridge retention member, starting at position <NUM>, where the cartridge retention member lands on the first guide member and continuing by the inflicted turning and longitudinal movement such that it is guided into the passage <NUM>. Thus, substantially irrespective of the angle at which the cartridge retention member is received, it is guided into the passage <NUM>.

Continuing its journey from a position, such as position <NUM>, in the passage, in the receiving direction, the cartridge retention member lands on a second guide member <NUM> of the second section <NUM> and in particular on a first section <NUM> thereof. Due to the inclined face of the first section <NUM>, a turning of the cartridge retention member <NUM> is inflicted, such that the cartridge retention member <NUM> turns from position <NUM> to position <NUM>, where it meets one of the first riser portions <NUM> which prevents further rotation. At this position, a user inserting the cartridge assembly will feel that the cartridge assembly stops moving, and will therefore intuitively release the force used for insertion. At this position <NUM>, a release of the force will make the spring-loaded ejector push the cartridge assembly and the cartridge retention member <NUM> outwards, opposite the receiving direction, to position <NUM>. At position <NUM> the cartridge retention member <NUM> lands on the slope portion <NUM> of a first guide member <NUM> leading towards the retention portion <NUM> at or about a bottom portion of the concave shape at a retention angle <NUM>. Due to the spring-loaded ejector working to push the cartridge retention member <NUM> outwards, the cartridge retention member <NUM> and hence the cartridge stays in a retention position, position <NUM>.

It should be noted that as the cartridge retention member travels out over the second riser portion <NUM>, it passes a point of no return and the inbound journey is generally not reversible. So, should the user ease the force used for insertion before position <NUM>, but after the point of no return, the cartridge still ends up in the retention position.

While in the retention position the cartridge and the cartridge assembly may be prevented from moving in the receiving direction by a lock that introduces a stop. Thereby the cartridge stays in its retention position even if a force overcoming the spring-load on the cartridge or cartridge assembly is overcome e.g. while the needle penetrates the skin. When the lock is released again to remove the stop, an outbound journey can start.

An outbound journey starts out from position <NUM> and is initiated when the spring-loaded force is overcome in the receiving direction, e.g. by a user pressing on a needle cover of the cartridge assembly. The cartridge retention member then lands on the second face <NUM> (cf. <FIG>) and in particular a first section <NUM> thereof at position <NUM>-<NUM>. Therefrom, it is brought to positon <NUM>. At this position, a user ejecting the cartridge assembly will feel that the cartridge assembly stops moving, since the cartridge retention member <NUM> meets a first riser portion <NUM>, and will therefore intuitively release the force used for ejecting the cartridge assembly. In releasing the force, the spring-loaded ejector will push the cartridge assembly and the cartridge retention member <NUM> outwards, opposite the receiving direction, to position <NUM>, where the cartridge retention member <NUM> meets an eject face <NUM> that guides the cartridge retention member <NUM> towards a position <NUM> in the passage <NUM> and onwards to a position <NUM> where the cartridge assembly is fully ejected and can be handled as needed e.g. to remove the cartridge from the cartridge assembly and dispose the cartridge.

It is noted that the direction of rotation, DR, is defined by the direction of the slopes of the first face and second face since they define in which direction turning is inflicted.

With respect to the length of an ejector rod <NUM> and the length of ejector cogs <NUM> thereof, to be explained in greater detail further below, it is noted that the cartridge retention member <NUM> should be allowed to travel between a first and a second extreme positions, L1 and L2, spaced apart at a longitudinal distance L12. At the position L2, the cartridge retention member <NUM> is at its retention position, i.e. an advanced position towards the cartridge receiver opening. At the position L1, the cartridge retention member <NUM> is at a 'deepest' position, in the receiving direction, given by the second face <NUM> or section <NUM> thereof. Thus, the ejector should be able to travel the distance L12. In some embodiments the position L3 may be located at a 'deeper' position than L1, in which case the ejector should allow the cartridge assembly retention member <NUM> to travel between L3 and L2.

<FIG> is a cross-sectional view of the first section of the cartridge receiver compartment. This cross-sectional view is orthogonal to the longitudinal axis and shows first guide member angles <NUM> and passage angles <NUM> that extend over the first guide members <NUM> and the passage <NUM>, respectively. The outwardly pointing apex of the first guide members is shown at a centre angle of the first guide member angles <NUM>. The first bore is indicated by reference numeral <NUM>.

The arrow designated by capital 'R' indicates a radial axis orthogonal to the longitudinal axis.

<FIG> is a cross-sectional view of the second section of the cartridge receiver compartment. This cross-sectional view is orthogonal to the longitudinal axis and shows the first sections <NUM> and the second sections <NUM> separated by first riser portions <NUM> and second riser portions <NUM>.

Each of one of the first sections <NUM> and each of one of the second sections <NUM> may extend over section angles. Section angles may by e.g. about <NUM> degrees.

<FIG> shows a detailed view of alternative first section and second section of the cartridge receiver compartment. The first guide members <NUM> of the first section <NUM> have a concave shape with a slope portion <NUM> that extends across the retention angle <NUM>.

The second guide members <NUM> of the second section <NUM> comprises a first face <NUM> that extends at least partly over passage angles <NUM> and first guide member angles <NUM>. A second face <NUM> extends between first faces, alternately. The first riser portions <NUM> separate the first faces <NUM> and the second faces <NUM>.

<FIG> shows an outer plunger rod. The outer plunger rod <NUM> is comprised by the plunger <NUM> and has a plunger rod front end <NUM> with a dimension that allows it to extend inside the cartridge to move a stopper therein. The outer plunger rod <NUM> may be moved by an inner plunger rod (not shown) and the inner plunger rod and the outer plunger rod may be coupled by threading such that turning of the inner plunger rod inflicts a longitudinal movement of the outer plunger rod <NUM>. The outer plunger rod <NUM> may be retained at an angle about the longitudinal axis by means of a longitudinally extending plunger rod groove <NUM> in the outer wall of the outer plunger rod.

The outer plunger rod <NUM> is configured with a plunger rod track <NUM>. The track <NUM> may extend from the rim of the outer plunger rod at the other end than the plunger rod front end <NUM>. The plunger rod track <NUM> has at least a first track portion <NUM> that leads an ejector lock guide pin <NUM> (cf. <FIG>) from a first angle to a second angle that are angularly spaced apart to turn the ejector lock <NUM> (cf. <FIG>) from the first angular position to the second angular position. A second track portion <NUM> extends from a plunger rod distal rim <NUM> along the longitudinal axis, L, towards and to connect with the first track portion <NUM> which is inclined with respect to the longitudinal axis e.g. at an angle of about <NUM>°, e.g. about <NUM>-<NUM>°, with respect to the longitudinal axis, L. Thereby the second track portion <NUM> accommodates the ejector lock guide pin <NUM> when the outer plunger rod <NUM> is in a forward position, towards the cartridge receiver opening <NUM>, to expel a medicament by moving the first stopper <NUM> in the first stopper direction as mentioned above. When the second track portion <NUM> accommodates the ejector lock guide pin <NUM>, the ejector lock <NUM> is angularly positioned to prevent the ejector rod <NUM> from moving backwards. A third track portion <NUM> connects with the first track portion <NUM> and continues along the longitudinal axis towards the plunger rod front end <NUM>. Thereby the third track portion <NUM> accommodates the ejector lock guide pin <NUM> when the outer plunger rod <NUM> is in a backward position, opposite the cartridge receiver opening <NUM>, whereat the outer plunger rod <NUM> is moved backwards, away from the first stopper <NUM>. Thus, the longitudinal position of the outer plunger rod <NUM> has the dual function of:.

This is explained in greater detail below.

Thus, the outer plunger rod part <NUM> is configured with a plunger rod track <NUM> that engages with the ejector lock guide pin <NUM> and extends from a plunger rod distal rim <NUM> towards plunger rod front end <NUM> and thus the cartridge receiver opening <NUM>.

<FIG> shows an ejector and an ejector lock. The ejector is generally designated <NUM> and comprises an ejector rod <NUM>. The ejector lock is configured to engage with the ejector rod by turning to thereby introduce a stop that prevents the ejector rod <NUM> from moving in the receiving direction.

The ejector rod <NUM> has an ejector collar <NUM> arranged about an ejector support face <NUM>, which supports the cartridge at a cartridge back face <NUM>, which may have the form of a rim. The ejector rod <NUM> has an ejector rod bore <NUM> to form a longitudinal passage all through the ejector rod <NUM>. The ejector rod bore <NUM> allows the outer plunger rod <NUM> to move along the longitudinal axis.

The ejector rod <NUM> is configured with one or more ejector cut-outs <NUM> to form one or more ejector cogs <NUM> between the ejector cut-outs <NUM>. Complementary therewith, the ejector lock <NUM> is configured with one or more ejector lock cogs <NUM> between one or more ejector lock cut-outs <NUM>, respectively. The ejector lock <NUM> is supported e.g. in a bearing that allows the lock to turn or be turned, at least a fraction of a revolution, while preventing a longitudinal movement. The ejector lock <NUM> may have a flange or a recess that engages with a complementary recess or protrusion, respectively, to maintain the ejector lock <NUM> in a fixed longitudinal position while allowing it to be turned at least a fraction of a revolution. The ejector cut-outs <NUM> are also denoted ejector slots <NUM>.

As shown, the ejector lock <NUM> has an angular position such that the ejector lock cogs <NUM> align with the ejector cut-outs <NUM>. The ejector rod <NUM> can thus move in the receiving direction until an end portion <NUM> of the ejector cogs abuts a bottom portion <NUM>, of the ejector lock cut-outs <NUM>, since the ejector lock cogs <NUM> and the ejector cogs <NUM> have substantially the same length. Thus, a bottom portion <NUM> of the ejector lock cut-outs <NUM> abuts the end portion <NUM> of the ejector cogs <NUM>. The end portion <NUM> of the ejector rod <NUM> is also denoted an ejector rest portion <NUM>.

When the ejector lock <NUM> is turned such that ejector cogs <NUM> align with ejector lock cogs <NUM>, a stop is introduced and the ejector rod <NUM> is prevented from moving in the receiving direction. The stop is introduced because, in that angular position of the ejector lock <NUM>, the end portion <NUM> of the ejector rod <NUM> abuts the ejector lock support portion <NUM> of the ejector lock <NUM>. The ejector lock support portion <NUM> of the ejector lock <NUM> is also denoted an ejector lock support portion <NUM>.

The ejector rod <NUM> may be prevented from turning, by means of an angle retaining guide <NUM> when it engages with an angle retaining slot <NUM> (cf. <FIG>), wherein the angle retaining slot <NUM> is arranged on or in the cartridge receiver <NUM> or a member rigidly coupled to the cartridge receiver <NUM>.

<FIG> shows an ejector lock. The ejector lock <NUM> is shown in greater detail here. It can be seen that the ejector lock <NUM> is configured with an ejector lock bore <NUM> accepting at least an end portion of the outer plunger rod <NUM>. An ejector lock guide pin <NUM> sits in the ejector lock bore <NUM> and extends inwardly from a wall thereof.

<FIG> shows various positions of the ejector relative to the ejector lock. In <FIG> the ejector rod <NUM> is shown in a longitudinal forward extreme position, relative to the ejector lock <NUM>, where it is spring-biased to be when a cartridge assembly is not inserted through the cartridge receiver opening, e.g. as shown in <FIG>. It can be seen that the ejector cogs <NUM> are aligned with ejector lock cut-outs <NUM>, although displaced far from each other, such that the stop is disengaged and the ejector rod <NUM> is thus allowed to move to an extreme position in the receiving direction. Thereby the inbound journey and the outbound journey described in connection with <FIG> can take place during insertion or ejection of a cartridge assembly.

In <FIG> the ejector rod <NUM> is shown in a longitudinal backward extreme position e.g. when a cartridge assembly retention member <NUM> is in contact with the second section <NUM> of the retention mechanism. This position of the cartridge assembly retention member <NUM> corresponds to the position L1 or L3 shown in <FIG>.

In <FIG> the ejector rod <NUM> is shown in a longitudinal position where the cartridge assembly retention member <NUM> is in the retention position abutting the bottom of the concave shape of the first guide member <NUM> of the first section <NUM>. This position of the cartridge assembly retention member <NUM> corresponds to the position L2 shown in <FIG>.

In <FIG> the ejector rod <NUM> is shown in the same longitudinal position as in <FIG>, but the ejector lock <NUM> is turned such that the stop is engaged. In this situation the ejector cogs <NUM> abuts the ejector lock cogs <NUM> end-to-end. Thus, an end portion <NUM> of the ejector cogs <NUM> abuts the end portion <NUM> of the ejector lock cogs <NUM>.

Thus, at least both of the length of the ejector rod <NUM> and the length of the cogs and the cut-outs should be dimensioned to allow the cartridge assembly retention member <NUM> to travel between position L1 and L2 and L3 and L2.

Thus, the elongated ejector <NUM> is suspended to move along the longitudinal axis, L, and is enabled to move beyond a stop position <NUM> (cf. <FIG>) at a first angular position of ejector lock <NUM> and is prevented from moving beyond the stop position <NUM> by the ejector cogs <NUM> abutting the ejector lock cogs <NUM> at a second angular position of the ejector lock <NUM> (cf. At the first angular position of ejector lock, the elongated ejector is enabled to move beyond the stop position, such as further until an extreme position <NUM> since the ejector cogs enter the ejector lock cut-outs <NUM> between the ejector lock cogs <NUM>. In some aspects the ejector rod is a substantially cylindrical rod coaxially arranged with the ejector lock, which comprises a substantially cylindrical portion.

<FIG> shows a cross section of an exemplary system <NUM> comprising an auto injector <NUM> and a cartridge assembly. The cartridge assembly <NUM> comprises a cartridge <NUM> with a cartridge compartment <NUM>, a needle assembly <NUM>, and a cartridge code feature <NUM>. The cartridge assembly <NUM> is received in the auto injector <NUM>. The auto injector <NUM> comprises the ejector rod <NUM> as described above. The ejector rod <NUM> is suspended for longitudinal movement and is spring-loaded by an ejector spring <NUM> which spring-loads the ejector rod <NUM> in the direction opposite of the receiving direction. Thereby, during insertion of the cartridge assembly <NUM>, the spring force exercised by the ejector spring <NUM> has to be overcome to insert the cartridge assembly into a position where it is held in a retention position.

The cartridge assembly <NUM> comprises a cartridge holder <NUM>. The cartridge holder <NUM> is configured for retention of the cartridge <NUM> in the cartridge receiver <NUM> of the auto injector <NUM>. The cartridge holder <NUM> comprises a cartridge retention member <NUM>. The cartridge retention member <NUM> engages with the cartridge receiver <NUM> for reception and retention of the cartridge <NUM> and the cartridge assembly <NUM> in the cartridge receiver <NUM>.

The needle assembly <NUM> comprises a needle <NUM> and a needle hub <NUM>. The needle assembly <NUM> is attached to the cartridge <NUM>, e.g. by the needle hub <NUM> having a cartridge holder coupling portion <NUM>, e.g. a threaded coupling portion, being in engagement with a needle assembly coupling portion <NUM> of the cartridge holder <NUM>. The needle <NUM> extends through the cartridge outlet <NUM> of the cartridge <NUM>. The cartridge outlet <NUM> may be blocked by a resilient sealing being penetrated by the needle <NUM>, when the needle assembly <NUM> is attached to the cartridge <NUM>.

The auto injector <NUM> comprises a code sensor <NUM> configured to read the cartridge code feature <NUM>. When the cartridge assembly <NUM> is inserted, as shown, the cartridge code feature <NUM> is lined up with the code sensor <NUM>.

The auto injector <NUM> comprises a plunger rod <NUM>. The plunger rod <NUM> is configured to advance a first stopper of the cartridge <NUM>. The plunger rod <NUM> comprises an outer plunger rod <NUM> with an inner thread, and an inner plunger rod <NUM> with an outer thread. The thread of the inner plunger rod <NUM> is in engagement with the thread of the outer plunger rod <NUM>. The outer plunger rod <NUM> is prevented from rotating relative to the housing of the auto injector. The movement of the plunger rod <NUM> comprises rotation of the inner plunger rod <NUM>. The rotation of the inner plunger rod <NUM> results in translational movement of the outer plunger rod <NUM>, due to the outer plunger rod <NUM> being rotationally restricted. The outer plunger rod <NUM>, when moved translationally in the first stopper direction <NUM>, is configured to abut the first stopper of the cartridge <NUM>, and to move the first stopper in the first stopper direction <NUM>.

The drive module <NUM> is coupled to actuate the plunger rod <NUM>. The drive module <NUM> is electrically connected to a battery for receiving electrical power. The drive module <NUM> comprises a motor <NUM>, such as an electromechanical motor, such as a DC motor. The drive module <NUM> comprises a transmission <NUM> for coupling the motor <NUM> to the inner plunger rod <NUM> of the plunger rod <NUM>.

The auto injector <NUM> comprises an ejection sensor <NUM>, such as a plunger rod position sensor. The ejection sensor <NUM> is configured to detect the position of the plunger rod <NUM>. In the illustrated example, the ejection sensor <NUM> comprises a tachometer configured to count/detect the revolutions of the motor <NUM>. Thus, the position of the plunger rod <NUM> may be determined based on the count of revolutions of the motor <NUM>. The ejection sensor <NUM> may, based on the detection of the position of the plunger rod <NUM>, detect the expelling of medicament and/or air in the cartridge compartment. The position of the plunger rod <NUM> may be indicative of the position of the first stopper of the cartridge <NUM>, e.g. the most advanced position of the plunger rod <NUM> during reception of the cartridge <NUM> may be indicative of the position of the first stopper of the cartridge <NUM>.

<FIG> show cross sections of a portion of an exemplary system comprising an auto injector and a cartridge assembly. The auto injector <NUM> comprises a cartridge receiver <NUM> configured for receiving and retaining a cartridge. The auto injector <NUM> comprises a contact member <NUM>. The contact member <NUM> may be movable between an extended contact member position and a retracted contact member position. The contact member <NUM> comprises a contact member protruding part <NUM>. The contact member protruding part <NUM> is configured to move with the contact member <NUM>. The contact member <NUM> may be biased, e.g. by a contact member spring (not shown), towards the extended contact member position.

The contact member comprises a needle cover engagement member <NUM>. The needle cover engagement member <NUM> is configured to abut a needle cover abutment face, e.g. of a needle cover positioned on the cartridge inserted into the cartridge receiver <NUM>.

The auto injector <NUM> comprises a contact member sensor <NUM> configured to detect a position of the contact member <NUM>. The contact member sensor <NUM> comprises a first contact member sensor <NUM> and a second contact member sensor <NUM>. The first contact member sensor <NUM> and the second contact member sensor <NUM> may be optical sensors. The contact member sensor <NUM> detects the position of the contact member <NUM> by the contact member protruding part <NUM> covering the first contact member sensor <NUM> when the contact member <NUM> is in a first contact member position, and the contact member protruding part <NUM> covering the second contact member sensor <NUM> when the contact member <NUM> is in a second contact member position.

The first contact member position may be detected by the first contact member sensor <NUM> being covered and the second contact member sensor <NUM> being covered. The second contact member position may be detected by the first contact member sensor <NUM> not being covered and the second contact member sensor <NUM> being covered. The extended contact member position may be detected by the first contact member sensor <NUM> not being covered and the second contact member sensor <NUM> not being covered.

<FIG> schematically illustrates the auto injector <NUM> with no received cartridge and/or cartridge assembly. The contact member <NUM> is in the extended contact member position. A cartridge may be inserted into the cartridge receiver <NUM> in the cartridge receiving direction <NUM> through the contact member <NUM> defining a cartridge receiver opening <NUM>.

<FIG> schematically illustrates the auto injector <NUM> with a cartridge assembly <NUM> received. The cartridge assembly comprises a cartridge <NUM>, a cartridge holder <NUM> and a needle assembly <NUM>. The needle assembly comprises a needle <NUM> and a needle cover <NUM>. The needle cover has a needle cover abutment face <NUM>. The needle cover abutment face <NUM> engages the needle cover engagement member <NUM> of the contact member <NUM>. The contact member <NUM> is in the second contact member position, e.g. caused by the presence of the needle cover <NUM> and the abutment of the needle cover abutment face <NUM> on the needle cover engagement member <NUM>. The contact member protruding part <NUM> covers the second contact member sensor <NUM>. The contact member protruding part <NUM> does not cover the first contact member sensor <NUM>.

<FIG> schematically illustrates the auto injector <NUM> with a cartridge assembly <NUM> received. Compared to Fig. 6b, the needle cover <NUM> has been removed. The contact member <NUM> is in the extended contact member position. The contact member <NUM> is allowed to be moved to the extended contact member position since the needle cover abutment face <NUM> does not about the needle cover engagement member <NUM>. The contact member protruding part <NUM> has moved with the contact member <NUM>. The contact member protruding part <NUM> does not cover the second contact member sensor <NUM>. The contact member protruding part <NUM> does not cover the first contact member sensor <NUM>.

<FIG> schematically illustrates the auto injector <NUM> with a cartridge assembly <NUM> received. The contact member <NUM> is in the first contact member position. The first contact member position may be the retracted contact member position, or close to the retracted contact member position. The contact member <NUM> may have been moved to the first contact member position by the contact member <NUM> being pressed against an injection site, thereby inserting the needle <NUM> into the injection site. The contact member protruding part <NUM> has moved with the contact member <NUM>. The contact member protruding part <NUM> covers the first contact member sensor <NUM>. The contact member protruding part <NUM> covers the second contact member sensor <NUM>.

<FIG> shows various positions of the ejector relative to the ejector lock in an embodiment where the cogs have inclined faces. In <FIG> the ejector rod <NUM> and the ejector lock <NUM> are in a mutual position where the stop is engaged. However, it can be seen that the ejector lock cogs <NUM> and the ejector cogs <NUM> have inclined end portions that abuts one another. Therefore, a further turning of the ejector lock <NUM> by a few degrees or a fraction of a degree may move the ejector <NUM> in the direction opposite of the receiving direction to displace it up to and tightly against the cartridge or cartridge assembly. Thereby, it is possible to reduce or eliminate clearances that would otherwise allow the cartridge to move slightly e.g. by as little as a fraction of a millimetre, but that could cause an inaccurate dose being expelled. The amount of tightening force may be controlled e.g. by monitoring current drawn by a motor coupled to drive the ejector lock.

In <FIG> the ejector <NUM> and the ejector lock <NUM> are in a mutual position where the stop is disengaged. Bottom portions of the ejector cut-outs <NUM> and/or the ejector lock cut-outs <NUM> may be inclined by the same angle as the end portions of the cogs to match the cogs or, as shown, have a substantially flat bottom portion, substantially orthogonal to the longitudinal axis.

According to a first item there is provided an auto injector (<NUM>) for dministering injection of a medicament from a cartridge containing the medicament, the auto injector (<NUM>) comprising: a housing (<NUM>); a cartridge receiver (<NUM>) with a cartridge receiver compartment (<NUM>) configured to receive a cartridge assembly (<NUM>), with at least one cartridge retention member (<NUM>), when inserted through a cartridge receiver opening (<NUM>) along a longitudinal axis (L) in a receiving direction; wherein the cartridge receiver (<NUM>) has a passage (<NUM>) through which the at least one cartridge retention member (<NUM>) travels at least in the receiving direction, and a member (<NUM>) preventing movement beyond a retention position in a direction opposite of the cartridge receiving direction (<NUM>); an elongated ejector (<NUM>) that is configured with: an ejector support face (<NUM>) for supporting the cartridge or cartridge assembly (<NUM>) and an ejector rod (<NUM>) configured with one or more ejector cut-outs (<NUM>) to form one or more ejector cogs (<NUM>) between the ejector cut-outs (<NUM>); and an ejector lock (<NUM>) supported for turning at least a fraction of a revolution and maintained in a longitudinal position relative to the housing (<NUM>); wherein the ejector lock (<NUM>) is configured with one or more ejector lock cogs (<NUM>) between one or more ejector lock cut-outs (<NUM>); wherein the elongated ejector (<NUM>) is suspended to move along the longitudinal axis (L) and is enabled to move beyond a stop position (<NUM>) at a first angular position of ejector lock (<NUM>) and is prevented from moving beyond the stop position (<NUM>) by the ejector cogs (<NUM>) abutting the ejector lock cogs (<NUM>) at a second angular position of the ejector lock (<NUM>).

At the first angular position of ejector lock, the elongated ejector is enabled to move beyond the stop position since the ejector cogs enter the ejector lock cut-outs. In some aspects the ejector rod is a substantially cylindrical rod coaxially arranged with the ejector lock, which comprises a substantially cylindrical portion.

The ejector lock may be coupled directly or indirectly to drive means comprising a motor to rotate to and from the first angular position and the second angular position. In some aspects the ejector lock is rotated by manual operation.

In some aspects the ejector rod <NUM> has an ejector rod bore <NUM>, forming a longitudinal passage through the ejector rod <NUM>, wherein a plunger rod <NUM> is arranged to move longitudinally. The Plunger rod may comprise an outer plunger rod with an inner, longitudinal thread, and an inner plunger rod, such as a threaded rod, coupled such that rotation of the inner plunger rod causes the outer plunger rod to move longitudinally. The outer plunger rod may be prevented from rotating, while the inner plunger rod is supported to rotate and kept in a fixed longitudinal position. The inner plunger rod may be driven by a motor.

In some aspects the ejector lock is operated to rotate to and from the first angular position and the second angular position by being coupled to the plunger rod, whereby a longitudinal displacement of the plunger rod rotates the ejector lock.

Claim 1:
An auto injector (<NUM>) for administering injection of a medicament from a cartridge containing the medicament, the auto injector (<NUM>) comprising:
a housing (<NUM>);
a cartridge receiver (<NUM>) with a cartridge receiver compartment (<NUM>) configured to receive a cartridge and/or a cartridge assembly (<NUM>), with at least one cartridge retention member (<NUM>), when inserted through a cartridge receiver opening (<NUM>) along a longitudinal axis (L) in a receiving direction; wherein the cartridge receiver (<NUM>) has a passage (<NUM>) through which the at least one cartridge retention member (<NUM>) travels at least in the receiving direction, and a member (<NUM>) preventing movement beyond a retention position in a direction opposite of the receiving direction;
an elongated ejector (<NUM>) that is configured with: an ejector support face (<NUM>) for supporting the cartridge or cartridge assembly (<NUM>), a longitudinal ejector slot (<NUM>) extending towards the ejector support face (<NUM>) from an ejector rest portion (<NUM>); wherein the elongated ejector (<NUM>) is suspended to move along the longitudinal direction and is spring-loaded in the direction opposite of the receiving direction; and
an ejector lock (<NUM>) supported for turning at least a fraction of a revolution and maintained in a longitudinal position relative to the housing (<NUM>); wherein the ejector lock (<NUM>) has an ejector lock support portion (<NUM>) that is configured to align with and slide along the longitudinal ejector slot (<NUM>) at a first angle and to be brought to align with the ejector rest portion (<NUM>) at a second angle
wherein at the first angle, movement of the cartridge assembly is allowed and at the second angle, movement of the cartridge assembly is restricted in the receiving direction at least from moving beyond a predefined longitudinal position.