Fixed dose injection device

Abstract

A drug delivery device for sequentially delivering a predetermined plurality of fixed doses, wherein the drug delivery device comprises a housing assembly, a drive mechanism comprising a drive tube and adapted to sequentially deliver the predetermined plurality of doses, and an activation mechanism for activating the drive mechanism. The drive mechanism further comprises a pre-tensioned torsion drive spring (108, 208) that holds an initial amount of energy and is adapted to rotate the drive tube, wherein each activation of the drive mechanism and completion of the dose sequence of the drive tube reduces the amount of energy held in the drive spring, and the initial amount of held energy that is held prior to the first activation is sufficient to deliver the predetermined plurality of fixed doses.

Description

Technical Field

[0001] This invention relates to a drug delivery device for delivering a predetermined plurality of fixed doses. More particularly, this invention relates to a drug delivery device in which the dispensing of fixed doses is driven by a pre-tensioned torsion spring. Background Technology

[0002] Drug delivery devices for self-administering various liquid drug formulations currently exist in a variety of shapes and sizes. Some are adapted to connect to infusion sets, while others can be connected to or integrated with injection needles. The latter type is referred to as injection devices. Some are durable devices that include a cartridge with a drug reservoir, where the cartridge can be replaced. Others are disposable devices that are discarded when the cartridge is empty. Disposable devices can be multi-dose devices, where the user can set the desired dose size before each injection, or single-dose devices, which can administer only a single dose of a given size. The latter involves so-called “shelter activation,” where the cannula is covered by a shelter at the front of the device, which releases the dose when pressed. Then, when the user presses the device against the skin, only the cannula is exposed to enter the skin, thereby depressing the shelter and releasing the dose. These injection devices are disposed of after a single injection.

[0003] Fixed-dose devices are preferred for some users because they may feel uncomfortable or be unable to operate the device to adjust the correct dose each time. For example, simplicity and ease of use are crucial to prevent user errors leading to overdosing or underdosing when children or the elderly use the device. In other cases, treatment protocols specify fixed doses, such as for GLP-1 inhibitors.

[0004] However, the device itself accounts for a large portion of the cost, not to mention the amount of materials used and therefore required for disposal. Therefore, it is desirable to manufacture a fixed-dose device capable of delivering multiple doses in a fixed volume.

[0005] In existing multi-dosing devices, the motor consists of a spring that coils up when the dose is adjusted. One solution is to manufacture a standard multi-dosing device where the maximum dose size is limited, so it can only be selected to a fixed dose size. However, this introduces the risk that the user may not select the correct dose and thus receive a smaller dose than intended. This problem has been addressed in WO2020089167, submitted by NovoNordisk, where a ratchet tube locks to the housing until the full dose has been set and the drive mechanism has been released.

[0006] Another fixed-dose device is disclosed in WO2019 / 09179 filed by Sanofi-Aventis. This disclosure relates to an injection device with a longitudinally movable dose tracker that provides automatic dose setting based on a pre-selected dose size. The disclosed injection device includes an elongated housing 10 extending along a longitudinal axis (z) and piston rods 20, 120 operatively engaged with a piston 7 of a cartridge 6 filled with a drug. The injection device also includes dose trackers 60, 150, 250, 350, 450, 550 operatively engaged with the piston rods 20, 120, wherein the dose trackers are proximally displaced relative to the housing 10 from an initial position (i) (see FIG. 25) toward at least a first activated position (a) (see FIG. 26) to set the dose, and wherein the dose trackers are distally displaced relative to the housing (10) from the activated position (a) toward the initial position (i) to dispense the dose. The injection device includes springs 80 and 144 to push the dose tracker in a proximal direction. The injection device also includes interlocking devices 84, 184, 284, and 584 for locking the dose tracker in an initial position (i), and release members 100, 101, 190, 290, and 590 for releasing the interlocking devices 84, 184, and 284. For example, if release member 190 is activated to release or release dose tracker 150, dose tracker 150 begins to rotate relative to the housing under the action of relaxed spring 144. An alternative fixed-dose device with selectable fixed dose sizes is disclosed in WO 2017 / 106221 filed by Merck Sharp & Dohme Corp. However, the possibility of selecting between different fixed dose sizes increases the complexity of the device, and the selection function is not always ideal. Alternatively, the ability to provide different fixed dose sizes can be achieved by using a set of two or more different fixed-dose devices.

[0007] An alternative fixed-dose device is disclosed in WO2018 / 007259 filed by Copernicus. This disclosure relates to an injection device for delivering a defined quantity of a dose of a fluid substance. The disclosed injection device includes a housing 1 having an arming mechanism and a dose delivery mechanism arranged along the longitudinal axis of the housing. The housing is coupled to a housing 3 for receiving a reservoir containing the fluid substance. The arming mechanism includes an axially non-displaceable mounting sleeve 5. The arming mechanism is rotatable about the axis of the housing in two opposite directions by a defined mounting angle (α). The mounting sleeve 5 is coupled to a torsion spring 10, which is tensioned by rotation of the mounting sleeve 5 during arming of the device. The dose delivery mechanism includes a helical ring 6 and a piston rod 4, which is non-rotatable and axially displaceable within the mounting sleeve 5. When the piston rod 4 cooperates with the helical ring 6, the helical ring 6 and the piston rod 4 are stationary during arming of the device. During each dose delivery, the piston rod 4 shifts a defined distance along the housing 1 due to the release of spring 10 and the rotation of the spiral ring 6. This shift of piston rod 4 causes the fluid substance to be discharged from the reservoir. It appears that the torsion spring must be tensioned in order to dispense the dose. An alternative design utilizing spring compression is described in WO 2017 / 098460, also filed by Copernicus. Another alternative device utilizing spring compression before each fixed dose is disclosed in WO94 / 26331, filed by Owen Mumford. However, keeping the device ready between doses is not always desirable because it requires the user to provide sufficient force to keep the device ready.

[0008] An alternative fixed-dose device is disclosed in WO2013 / 034651 filed by Menarini. This disclosure relates to a device for automatically injecting two doses of a drug in two consecutive injections. The disclosure describes an automatic injection device including a sliding sheath 30 that interacts with cam devices 26, 27, 28 when its front end 3 presses against the injection site to activate the triggering of a plunger 8, thereby controlling the delivery of the drug dose. A plunger guide 44 is disposed on the inner surface of a housing 1 for controlling the triggering sequence, and a dose knob 4 is used to prepare or set the device in the dose delivery state. The device is adapted to automatically re-lock the needle and reset the locking state after each dose delivery. This reduces the number of device parts, resulting in a simpler structure and lower cost. Devices with similar functionality by the same applicant are disclosed in WO2013 / 034647 and WO2011 / 111006. It appears that all alternatives use a compression spring as the power source for driving the plunger.

[0009] US 2013 / 0096513, WO 2014 / 060369, and WO 2014 / 198858 all describe drug delivery devices driven by torsion springs, wherein the torsion springs are tensioned during dose setting. US 2013 / 0096513 relates to a fixed-dose drug delivery device, while WO 2014 / 060369 and WO 2014 / 198858 relate to drug delivery devices with variable doses.

[0010] Therefore, there is an unmet need for alternative injection devices for delivering predetermined fixed doses, which addresses the need for simple, safe, user-friendly and robust drug delivery devices.

[0011] In view of the above, the object of the present invention is to provide a user-friendly, safe and robust drug delivery device for delivering a predetermined number of fixed doses. Summary of the Invention

[0012] In the disclosure of this invention, a number of embodiments and aspects will be described that will solve one or more of the above-described objectives, or objectives that will be apparent from the following disclosure and from the description of exemplary embodiments.

[0013] In a first aspect, a drug delivery device is provided for sequentially delivering a predetermined plurality of fixed doses of a drug, wherein the drug delivery device comprises:

[0014] - Housing components,

[0015] - A drive mechanism including a drive tube, wherein the drive mechanism is adapted to sequentially deliver a predetermined plurality of doses, and,

[0016] - An activation mechanism for activating the drive mechanism.

[0017] The drive mechanism includes a pre-tensioned torque drive spring (108, 208) that stores an initial amount of energy and is adapted to rotate the drive tube. Each activation of the drive mechanism and the completion of the drive tube dose sequence reduces the amount of energy stored in the drive spring, and the initial amount of stored energy, which is the energy stored before the first activation, is sufficient to deliver the predetermined plurality of fixed doses.

[0018] Therefore, a drug delivery device is provided for delivering a predetermined plurality of fixed doses without requiring the drive mechanism to be ready for activation or tensioned between doses, because the energy stored before the first activation is sufficient to deliver the predetermined plurality of fixed doses. The fixed-dose drug delivery device according to the invention is suitable for delivering doses of the desired volume multiple times. The predetermined quantity is determined by dividing the total amount of drug by the desired volume of the fixed dose. Each activation of the drive mechanism reduces the stored energy because the spring is not tensioned before each dose.

[0019] On the other hand:

[0020] - The housing assembly includes a guide structure, which includes a stop and activate guide portion and a drive guide portion;

[0021] - The drive tube is adapted to be guided along the stop and activate guide portion to activate the drive mechanism, and along the drive guide portion to deliver a fixed dose, and guided to the stop and activate guide portion, wherein dosing is stopped, thereby the drive tube is adapted to be guided in response to the execution of a drive tube dosing sequence including activation, dosing, and stopping dosing;

[0022] - The drive mechanism further includes a piston rod operably connected to the housing assembly and the drive tube.

[0023] The activation mechanism is adapted to move the drive tube from a first axial position to a second axial position along the stop and activation guide portion in a first axial direction, thereby activating the drive mechanism.

[0024] On the other hand, the drive mechanism is also adapted to bias the drive tube in a second axial direction opposite to the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube along the drive guide portion to the stop and activate guide portion in response to activation of the drive mechanism, thereby delivering a fixed dose of the predetermined plurality of fixed doses, and wherein the drive tube is operatively positioned to be guided along the stop and activate guide portion to deliver a subsequent fixed dose of the plurality of fixed doses.

[0025] In another or alternative aspect, the housing further includes internal threads, wherein the piston rod further includes external threads for threaded engagement of the internal threads of the housing assembly, wherein the drive tube is axially connected to the piston rod by a spline, thereby allowing the drive tube to be axially moved and rotated relative to the drive tube for locking, thereby allowing the piston rod to be operatively connected to the housing assembly and the drive tube.

[0026] In another or alternative aspect, the torsion drive spring is compressed, thereby adapting the drive mechanism to bias the drive tube in the second axial direction. Therefore, the drive spring is adapted to bias the drive tube toward the first position during metered administration, thereby ensuring that the guiding surface remains intact during metered administration.

[0027] In another or alternative aspect, the drug delivery device includes an axially movable spring base, wherein the drive mechanism includes a compression return spring located between the axially movable spring base and the housing, whereby the torque drive spring and the return spring are connected in series, thereby adapting the drive mechanism to bias the drive tube in the second axial direction.

[0028] In another or alternative aspect, the drug delivery device is adapted to deliver a drug at a distal end, wherein the drug delivery device includes a central axial axis defined between the distal and proximal ends, wherein the drug delivery device includes a slidably arranged spring base, wherein the torsion spring is arranged between the spring base and the drive tube, wherein the drive tube is positioned during activation and dosing such that the component of the central axial axis in the direction opposite to the direction of gravity is the second axial direction, thereby biasing the drive tube in the distal direction, thereby adapting the drive mechanism to bias the drive tube in the second axial direction.

[0029] In another or alternative aspect, the torsion drive spring is arranged between the drive tube and the housing assembly.

[0030] In another or alternative aspect, the housing assembly includes a fixed spring base, wherein one end of the torque-driven spring is attached to the fixed spring base. Therefore, the spring base becomes a fixed part of the housing assembly.

[0031] In another or alternative aspect, the stop and activate guide portions of the guide structure are axial portions, and the drive guide portion of the guide structure of the housing assembly includes a helical portion.

[0032] In another or alternative aspect, the stop and activate guide portions of the guide structure are axial portions, and the drive guide portion of the guide structure of the housing assembly includes a transverse portion.

[0033] In another or alternative aspect, the stop and activate guide portion of the guide structure is an axial portion, and the drive guide portion of the guide structure of the housing assembly includes a stepped portion, the stepped portion including a portion from a first group including transverse and helical portions and a portion from a second group including radial, helical and axial portions.

[0034] In another or alternative aspect, the drive tube includes a corresponding guide structure adapted to cooperate with the guide structure of the housing assembly.

[0035] In another or alternative aspect, the guide structure of the drive tube includes an axial portion and a helical portion.

[0036] In another or alternative aspect, for the drive tube in the first position, the housing assembly and the axial portion of the guide structure of the drive tube are abutted, and the helical portion of the housing assembly and the guide structure of the drive tube are abutted, wherein, for the drive tube in the second position, an axial clearance is provided between the housing assembly and the axial portion of the drive tube, whereby the helical portion of the drive tube can slide onto the helical portion of the housing assembly.

[0037] In another or alternative aspect, each delivered dose has an equal volume.

[0038] In another or alternative aspect, the drug delivery device includes an actuation mechanism, whereby each delivered dose has an equal volume.

[0039] In another or alternative aspect, the drive spring is pre-tensioned with a constant force to deliver a predetermined number of doses, wherein the force can be measured as an axial force transmitted from the piston rod, and wherein the constant force is defined as the force that varies by less than 20 percent between the first dose and the last dose.

[0040] In another or alternative aspect, the predetermined plurality of fixed doses is 2, 3, 4, 5 or 6, preferably 4.

[0041] In another or alternative aspect, the drug delivery device includes a drug filling cylinder having a piston arranged proximally, wherein the piston rod is operatively arranged to advance the piston.

[0042] In another or alternative aspect, the drug delivery device includes an integrated needle, and wherein the activation mechanism includes an axially movable needle shield for covering and exposing the needle, wherein the shield is adapted to activate the drive mechanism in response to movement in the proximal direction, thereby exposing the needle.

[0043] In another or alternative aspect, the drug delivery device includes a needle hub for an injection needle, and wherein the activation mechanism includes an axially movable release button adapted to activate the drive mechanism in response to axial movement.

[0044] In another or alternative aspect, the activation mechanism includes a connector operatively connected to the drive mechanism, wherein the connector is adapted to activate the drive tube in response to axial movement.

[0045] In another or alternative aspect, the activation mechanism includes a shield for covering the integrated needle tip and a connector operably connected to the drive mechanism, wherein the shield is operably arranged to engage the connector in response to rotation of the shield, and wherein the shield is axially movable and adapted to move the connector, thereby adapting to activate the drive tube in response to axial movement.

[0046] In another or alternative aspect, the first position of the drive tube is the distal position and the second position is the proximal position.

[0047] In another or alternative aspect, the drug delivery device is an injection device.

[0048] In another or alternative aspect, the drug delivery device further includes a drug reservoir with a piston arranged to discharge drug from the reservoir, wherein a piston rod is adapted to axially advance the piston, wherein the piston rod is axially splined to the housing assembly, thereby allowing the piston rod to be axially moved and rotated to lock relative to the housing assembly, wherein the drive tube further includes an internal thread, and wherein the piston rod further includes an external thread for threading engagement of the internal thread of the drive tube, thereby allowing the piston rod to be operatively connected to the housing assembly and the drive tube, wherein the drive mechanism further includes a compression drive spring for axially moving the drive tube and the piston, thereby allowing the drive mechanism and drive and return guide to return the drive tube to the first position.

[0049] In another or alternative aspect, the drug delivery device further includes an axially movable spring base, wherein the compression drive spring is located between the spring base and the housing, thereby connecting the torque drive spring and the compression drive spring in series.

[0050] In another or alternative aspect, the compression drive spring is integrated with the torsion drive spring.

[0051] On the other hand, the drive spring is pre-tensioned with a constant force to deliver a predetermined number of doses.

[0052] On the other hand, the housing assembly includes a guide structure, which includes a stop and activate guide portion and a drive guide portion.

[0053] On the other hand, the drive tube is adapted to be guided along the stop and activate guide portion to activate the drive mechanism, and along the drive guide portion to deliver a fixed dose, and guided to the stop and activate guide portion, wherein dosing is stopped, thereby the drive tube is adapted to be guided in response to the execution of a drive tube dosing sequence including activation, dosing, and stopping dosing;

[0054] On the other hand, the drug delivery device includes a reservoir with a piston, wherein the drive mechanism further includes a piston rod for engaging and advancing the piston rod to dispense the dose.

[0055] In a second aspect of this disclosure, a drug delivery device is provided for sequentially delivering a predetermined plurality of fixed doses of a drug, wherein the drug delivery device comprises:

[0056] - A housing assembly including a guide structure, the guide structure including a stop and activate guide portion and a drive guide portion;

[0057] - A drive mechanism adapted to sequentially deliver a predetermined plurality of doses, wherein the drive mechanism comprises:

[0058] - A drive tube adapted to be guided along the stop and activate guide portion to activate the drive mechanism, and along the drive guide portion to deliver a fixed dose, and guided to the stop and activate guide portion, wherein dosing is stopped, thereby the drive tube is adapted to be guided in response to the execution of a drive tube dosing sequence including activation, dosing, and stopping dosing;

[0059] - A torsion drive spring, which stores an initial amount of energy and is adapted to rotate the drive tube.

[0060] - A piston rod, operably connected to the housing assembly and the drive tube.

[0061] - An activation mechanism adapted to move the drive tube along the stop and activation guide portion from a first axial position to a second axial position in a first axial direction, thereby activating the drive mechanism.

[0062] The drive mechanism is further adapted to bias the drive tube in a second axial direction opposite to the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube along the drive guide portion to the stop and activate guide portion in response to activation of the drive mechanism, thereby delivering a fixed dose of a predetermined plurality of fixed doses, and wherein the drive tube is operatively positioned to be guided along the stop and activate guide portion to deliver a subsequent fixed dose of the plurality of fixed doses.

[0063] Each activation of the drive mechanism and the completion of the drive tube dose sequence reduces the amount of energy stored in the drive spring, and the initial amount of stored energy, which is the energy stored before the first activation, is sufficient to deliver a predetermined number of fixed doses.

[0064] Therefore, a drug delivery device is provided for delivering a predetermined plurality of fixed doses without requiring the drive mechanism to be ready for activation or tensioned between doses, because the energy stored before the first activation is sufficient to deliver the predetermined plurality of fixed doses. It appears that the volume of the fixed dose is determined by the housing and the guide of the drive mechanism. Therefore, the fixed-dose drug delivery device according to the invention is suitable for delivering doses of the desired volume multiple times. The predetermined quantity is determined by dividing the total amount of drug by the desired volume of the fixed dose. Similarly, with the fixed-dose drug delivery device according to the invention, the fixed dose can only be adjusted by modifying the drive mechanism and the guide of the device. Attached Figure Description

[0065] The following embodiments of the invention will be described with reference to the accompanying drawings, in which:

[0066] Figure 1A An exploded view of an injection device according to a first embodiment of the present disclosure is shown.

[0067] Figure 1B It shows Figure 1A Details of the cartridge holder in the embodiment shown.

[0068] Figure 1C It shows Figure 1A Details of the protective cover and movable portion of the cleaning component in the embodiment shown. Figure 1C The structure is shown in black and white and in grayscale in window W1, where the piston is separated from the chamber.

[0069] Figure 1D-1F It shows Figure 1A Details of the protective sheath following portion, cannula, needle interface, and cartridge engagement structure of the cleaning assembly shown in the embodiment. Figure 1F In the middle, window W2 shows the components in grayscale, and W3 shows a portion of the interface in grayscale to display the guide on the inner surface.

[0070] Figures 2A-2D It shows Figure 1A Further details of the cleaning components in the embodiments shown. Figure 2B , 2C The structure is shown in black and white in 2D and in grayscale in windows W4, W5, and W6 to increase the assessability of gaps, sloping surfaces, and separation sections. Window W6 is angled to show the slits in the interface.

[0071] Figures 3A-3F It shows Figure 1A Details of the guide structure of the elongated shell structure shown in the embodiment.

[0072] Figure 4A and 4B It shows Figure 1ADetails of the zero-point adjusting nut in the embodiment shown.

[0073] Figure 5 The setting is shown Figure 1A Further details of the zero-point adjustment mechanism on the elongated housing structure of the embodiment shown.

[0074] Figure 6 It shows Figure 1A A cross-sectional view of the proximal portion of the injection device of an embodiment. The illustrated injection device includes a piston washer.

[0075] Figure 7 It shows Figure 1A Details of the piston rod in the embodiment shown.

[0076] Figures 8A-8B It shows Figure 1A Details of the drive transistor in the embodiment shown.

[0077] Figures 9A-9B It shows Figure 1A Details of the housing insertion portion of the embodiment shown.

[0078] Figures 10A-10C It shows Figure 1A Details of the elongated shield structure of the embodiment shown.

[0079] Figure 11A-11B It shows Figure 1A Details of the connector in the embodiment shown.

[0080] Figure 12A-12B Cross-sectional views of the proximal end of the injection device are shown from two different angles. The illustrated device is similar to... Figure 1A The embodiments shown are the same.

[0081] Figures 13A-13D It shows Figure 1A Details of the drive mechanism in the embodiment shown.

[0082] Figures 14A-14B Cross-sectional views of the entire injection device are shown from two different angles. The device illustrated is related to... Figure 1A The embodiments shown are the same.

[0083] Figures 15A-15B It shows in Figure 1A User operations and status during the operation of the injection device. Figure 15A The procedure for administering the first fixed dose is shown, and 15B shows the subsequent doses.

[0084] Figure 16A-16T It shows the different states and intermediate arrangements. Figure 1AThe injection device is provided, and detailed illustrations of its operation are given.

[0085] Figure 17 An exploded view of an injection device according to a second embodiment of the present disclosure is shown.

[0086] Figure 18 Detailed illustration Figure 17 A cross-sectional view of the embodiment shown.

[0087] Figure 19 It shows Figure 17 Details of the housing in the embodiment shown.

[0088] Figure 20 It shows Figure 17 Details of the inner tubular portion of the housing in the embodiment shown.

[0089] Figure 21 It shows Figure 17 Details of the relocking tube in the embodiment shown.

[0090] Figure 22 It shows Figure 17 Details of the connector in the embodiment shown.

[0091] Figures 23A-23B It shows Figure 17 Details of the drive transistor in the embodiment shown.

[0092] Figure 24 It shows Figure 17 Details of the elongated shield structure of the embodiment shown.

[0093] Figures 15A-15B It shows in Figure 1A User operations and status during the operation of the injection device. Figure 15A The procedure for administering the first fixed dose is shown, and 15B shows the subsequent doses.

[0094] Figures 25A-25G show different states and intermediate arrangements. Figure 17 The injection device is provided, thus providing a detailed illustration of the operation of the device during the first dose.

[0095] Figures 26A-26B illustrate the different states and intermediate arrangements during subsequent doses. Figure 17 The injection device.

[0096] In the accompanying drawings, similar structures are primarily identified by similar reference numerals. Reference numerals followed by the letter "a" indicate the distal end of the structure, while those followed by "b" indicate the proximal end. Reference numerals including the first and second numerals followed by a "." are used to indicate the function or structural detail of the structure. In this way, the first numeral indicates the primary (relatively large) structure, and the second numeral indicates the secondary (relatively small) structure or specific function. Reference numerals followed by the letters "c," "d," and "e" indicate features exhibiting rotational symmetry. Detailed Implementation

[0097] When using terms such as “up” and “down,” “right” and “left,” “horizontal” and “vertical,” or similar relative expressions, these terms are for reference only with respect to the accompanying drawings and do not necessarily represent the actual usage context. The accompanying drawings are schematic representations, and therefore the construction of different structures and their relative dimensions are for illustrative purposes only. When the term “component” is used with respect to a given part, it can be used to define a single part or a portion of a part that has one or more functions.

[0098] In the following detailed description, further specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without these specific details. In other instances, well-known methods, processes, components, circuits, and networks have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments.

[0099] It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first subject may be referred to as a second subject, and similarly, a second subject may be referred to as a first subject. Both the first subject and the second subject are subjects, but they are not the same subject. Furthermore, the terms "subject," "user," and "patient" are used interchangeably herein.

[0100] As used herein, the term "if" can be interpreted as meaning "when," "after," "in response to determination," or "in response to detection," depending on the context. Similarly, the phrases "if determination" or "if [the condition or event of the statement] is detected" can be interpreted as meaning "after determination," "in response to determination," "after [the condition or event of the statement] is detected," or "in response to [the condition or event of the statement]," depending on the context.

[0101] As used herein, the terms distal and proximal are analogous to anatomical terms used to describe ends located remotely from or closest to the body attachment points. Therefore, the distal end of an injection device is defined in the context of the user holding the device in a ready-to-injection position, whereby the end with the injection needle will be the distal end, and the opposite end will be the proximal end. Furthermore, the distal and proximal ends of the various components of the device are also defined in this context.

[0102] As used in this paper, the front edge and rear edge are used to describe the edges of a structure that moves relative to another structure. The front edge is the edge in the direction of movement, while the rear edge is the opposite. In this way, the front and rear edges are defined according to the direction of relative movement between the structures.

[0103] As used in this article, rotational symmetry is a property of structures that appear identical or function identical after several rotations of a portion of their structure. The degree of rotational symmetry of a structure is the number of different orientations that appear identical with each rotation. n-order rotational symmetry, where n is 2 or greater, is also called n-fold rotational symmetry relative to a specific point (in 2D) or an axis (in 3D), or n-order discrete rotational symmetry, meaning that rotating by an angle of 360° / n does not change the object. The properties of a structure can relate to both the visible appearance and functional capabilities of its structural features.

[0104] As used herein, the term clockwise direction describes the direction in which the hands of a clock rotate when viewed from the front. Therefore, clockwise rotation of the injection device is the clockwise rotation observed when viewing the device from the distal front. Counterclockwise or reverse clockwise rotation is defined as the opposite direction.

[0105] As used herein, the proximal side is the face of the device viewed from the proximal end and in the distal direction, while the distal side is the face of the device viewed from the distal end and in the proximal direction.

[0106] As used herein, the positive axis or longitudinal direction is defined from the proximal end to the distal end. The positive axis and distal direction are used interchangeably and have the same meaning. Similarly, the negative axis and proximal direction are defined interchangeably and have the same meaning. The central axis of the device is defined as passing through the center of the injection device in the positive axis direction; it is also called the longitudinal axis, and has the same meaning.

[0107] As used in this article, the positive radial direction is defined along the radial axis originating from the central axis and has a direction perpendicular to the central axis.

[0108] A positive circumferential direction or positive angular direction is defined for a point located at a radial distance from the central axis, wherein the circumferential direction is counterclockwise and perpendicular to both the axial and radial directions. As used in this disclosure, the direction can be positive and negative. For example, the term axial direction encompasses a positive axial direction from the proximal end to the distal end and a negative axial direction in the opposite direction.

[0109] Both the radial and circumferential directions are referred to as transverse directions in this paper because they are transversely perpendicular to the axial direction. For a given coordinate along the axis, the transverse plane is defined in this paper as the plane spanned by two vectors in the radial and circumferential directions, with the central axis as the normal vector.

[0110] As used herein, axial motion of a structure is used to describe a motion in which the displacement vector of the structure has a component in the axial direction. Translational motion is used only to describe uniform motion in the axial direction. Pure, strict, or uniform axial motion is the same as translational motion, and these terms are used interchangeably.

[0111] Radial motion of a structure is used to describe a motion in which the displacement vector of the structure has a component in the radial direction. Pure or strict radial motion is used only to describe uniform motion in the radial direction. Therefore, pure, strict, and uniform radial motion are the same, and these terms are used interchangeably.

[0112] Circumferential, angular, or rotational motion of a structure is used to describe a motion in which the displacement vector of the structure has a component in the circumferential direction. Pure or strictly circumferential motion is used only to describe uniform motion in the circumferential direction. Therefore, pure, strictly, and uniform circumferential motion is the same as pure, strictly, and uniform angular or rotational motion, and these terms are used interchangeably. The definition of rotational motion of a structure also includes a special case where the structure comprises a central axis defining the axis of rotation. In this special case, all positions of the structure deviating from the central axis are subject to circular motion, while the displacement vector of positions on the central axis is zero. Therefore, the rotation of a structure about its own central axis and its movement in the axial direction is called rotational motion.

[0113] Helical motion of a structure is used to describe a combination of axial and angular or rotational motions, where the displacement vector of the structure includes both circumferential and axial components. The definition of helical motion also includes a special case where the structure comprises a central axis defining the axis of rotation. In this special case, all positions of the structure deviating from the central axis are subject to helical motion, while the displacement vector of positions on the central axis includes only the axial component. Therefore, the rotation of a structure around its own central axis and its axial movement is referred to as helical motion.

[0114] In this context, pure, rigorous, and uniform motion are abstract mathematical definitions, and these terms are used to describe the ideal or abstract motion of a device. Therefore, one should not expect a structure in a real device to exhibit this ideal behavior, but rather expect it to move in a pattern that approximates this ideal motion.

[0115] As used herein, a right-hand thread or helical portion is a thread or helical portion in which the helix moves in the positive axial direction when the screw is turned clockwise. Screws with right-hand threads are typically the default thread and are turned in the positive axial direction by a counter-clockwise rotation, usually performed by the right hand. Similarly, screws with left-hand threads are turned in the positive axial direction by a clockwise rotation, and therefore can be performed with the left hand and are a mirror image of the movement of a right-hand thread operated by the right hand.

[0116] Embodiments of this disclosure are described in detail with respect to injection devices including reusable integrated needle cannulas with a clean chamber, wherein the injection device is adapted to provide multiple predetermined fixed doses. However, in alternative embodiments, a needle cartridge as described in EP20157959.6 entitled "Injection Device with Integrated Needle" may be integrated instead of a single reusable needle submitted by NovoNordisk.

[0117] First Embodiment

[0118] Figures 1-16 illustrate a first embodiment of an injection device for delivering multiple fixed doses according to the present disclosure. Figure 1A An exploded view of this injection device is shown. Figure 1B -14 shows additional details of the individual structures and mechanisms. Figure 15A and 15B A series of states during the use of the injection device 100 are shown in perspective, thus illustrating user operations from the receiving device, the initiating device, and the delivery of multiple fixed doses. Figure 16 shows in detail the interrelationships of the mechanical structures during operation. As used herein, states define a certain arrangement or configuration of the device, and states and operations provide a framework for explaining how the device works.

[0119] Figure 1A The cap 105, the shield tip 119, and the shield follow-up portion 120.1 of the cleaning module 120 are shown (see [reference]). Figure 2B The device includes a needle interface 125 with a needle cannula 124, a housing insertion portion 160, a tubular elongated needle guard structure 110, a cartridge holder 130, a cartridge 135, a tubular elongated housing structure 140, a connector 170, a guard return spring 107, a drive tube 180, a dose drive spring 108, a piston rod 109, and a spring base 165.

[0120] housing assembly

[0121] The injection device includes a housing assembly that provides a rigid frame with guides and connectors for guiding and connecting other components of the device. The housing assembly includes a housing insert 160, a tubular elongated housing structure 140, a cartridge holder 130, and a spring base 165. These structures are fixedly connected after final assembly, and the housing assembly provides a reference frame for describing the relative movement and position of the other structures. The elongated housing structure 140 includes internal threads for engaging the external threads of a piston rod. The internal threads may be provided as an integral nut member rotatably and axially fixed to the housing structure 140. In one example, the nut member is an integral part of the housing structure 140. Alternatively, the nut member may be a separate part fixed to the housing during assembly of the injection device, for example, by adhesive or welding. The nut member has internal threads on its inner surface that engage with the external threads of the piston rod 109, causing the piston rod to move helically as it rotates relative to the housing structure. Alternatively, the internal threads are directly provided within the housing. The housing insert 160 includes a cap latch at the end of a track with a capped bayonet. The housing insertion portion 160 also includes a proximal edge for guiding the shroud. For further description, the housing assembly may be simply referred to as the housing, and the needle shroud assembly may be simply referred to as the needle shroud.

[0122] The injection device 100 includes a drive mechanism and a triggering or activating mechanism. The drive mechanism includes a piston rod 109, a drive spring 108, and a drive tube 180, and these structures are operatively arranged within a housing for dispensing the dose. The triggering mechanism includes an elongated shield structure 110 and a connector 170, and these structures are operatively arranged within a housing for triggering the dose dispensing mechanism.

[0123] Needle shield assembly

[0124] The injection device also includes a needle shield assembly comprising a shield tip 119 and an elongated shield structure 110. The elongated shield structure 110 includes a window 111 for inspecting the medication. The elongated shield can be positioned in a first location that overlaps with a cartridge holder window 131 and in a second location that does not overlap, wherein a solid portion of the elongated shield structure covers the window 131 in the second location.

[0125] cartridge holder

[0126] The cartridge holder 130 is adapted to receive a cartridge 135. The cartridge holder includes a window 131 for checking the drug in the cartridge 135. Figure 1B The cartridge holder 130 is shown in outline, the cartridge holder including an axial rib 132 for axially guiding the needle interface and a neck 137 for snapping onto the cartridge. Figure 1AThe flexible arm and the proximal extension tab 130.1 for aligning and positioning the cartridge case when inserted into the housing during assembly. A circumferentially extending flange 134 is provided on the inner surface at the distal end of the cartridge case holder to provide a small axial clearance with the distal surface of the cartridge case after assembly and in the initial packaged out-of-package state.

[0127] medicine tube

[0128] like Figure 1A As further shown in Figure 1, the elongated cartridge 135 includes a distal end 135a sealed by a puncturable diaphragm and an open proximal end 135 closed by a piston. The piston is not shown in Figure 1. The cartridge includes multiple fixed-dose reservoirs containing a drug. A diaphragm covered by a cap is disposed at the distal end 135a. The cap and the main portion of the reservoir are separated by a neck 137.

[0129] Needle assembly

[0130] The injection device also includes a needle assembly comprising a needle interface 125 and a reusable needle cannula 124. The cannula includes a proximal end for piercing a punctureable septum and establishing fluid communication with a reservoir, and a distal end for insertion into the skin of a subject or user.

[0131] Piston gasket

[0132] Although not shown in Figure 1, a piston washer can be attached to the piston rod to provide a pressure foot for contacting the piston. Alternatively, a dose measurement module for measuring the relative rotation between the piston rod and the piston can be disposed between the piston rod and the piston. Such a measurement module also provides a suitable pressure foot. Such a dose measurement module is described in WO20141128155 entitled "Dose capturing cartridge module for drug delivery device". Alternatively, the piston rod directly contacts the piston.

[0133] cap

[0134] The cap 105 is adapted to be releasably installed into the housing insert portion 160. The cap includes a protrusion 105.2. Figure 16F The inner surface of the cap 105 includes protrusions adapted to be guided by axial and circumferential cap mounting rails 161, which will be described in detail later in this application. The protrusions are also adapted to cooperate with a snap-lock 161.1, thereby releasably locking the cap 105 to the inner housing portion 160. The cap is adapted to be installed and removed by sequential axial and rotational movements, thus providing a bayonet engagement with the injection device. The inner surface of the cap 105 also includes axially extending ribs 105.1. Figure 16AThe axially extending ribs project from the inner surface and adapt the cap to transmit torque to the cover structure 110 via the axially extending ribs 116 on the outer surface of the cover, as will be referred to later. Figure 16A Explanation.

[0135] Spring base

[0136] The spring base 165 is fixedly mounted to the housing structure 140 at the proximal end and is adapted to receive and support the compressible torque-driven spring 108.

[0137] Drive spring

[0138] The drive spring 108 is pre-tensioned or coiled and positioned between the spring base and the drive tube 180. The drive spring is also adapted to generate torque on the drive tube, thereby discharging the medication. The drive spring includes torsional sections 108.3 and 108.4 with relatively small spacing between the coils, and a compressible section 108.4 adapted to transmit axial force to the drive tube after compression and during medication discharging. The ability to drive the drive tube in the axial direction enables the dosing termination mechanism and allows the drive tube to be reset.

[0139] Return spring

[0140] The connector return spring 107 is positioned between the spring base 165 and the connector 170 and is adapted to push the connector in the distal direction.

[0141] Cleaning components

[0142] Cleaning the needle between injections allows for the reuse of the same integrated needle under clean conditions multiple times. Therefore, in an alternative embodiment of this disclosure, the injection device includes a cleaning assembly 120, such as... Figure 2B As shown in the diagram. The movable shield structure 110 is fixedly connected to the cleaning assembly 120 via a shield follower portion 120.1, and the principle of the cleaning module is disclosed in further detail in WO2019 / 101670. The cleaning assembly 120 includes a cleaning agent that keeps the distal end of the needle cannula 124 clean between injections. The shield follower portion 120.1 of the cleaning module is fixedly connected to a shield tip 119, which in turn is fixedly connected to the movably arranged elongated needle shield structure 110. The shield tip 119 can be snapped into the needle shield structure 110 via an elastic arm 119.1 engaging the elongated shield structure 110, such that the cleaning chamber assembly 120 follows the axial and rotational movement of the movably arranged shield structure 110. The shield structure 110 connected to the cleaning assembly 120 is movably arranged relative to the needle cannula 124 fixed to the housing.

[0143] The cleaning assembly 120 preferably includes a chamber containing a liquid cleaning agent. In one example, the liquid cleaning agent may be the same preservative contained in the liquid medication in cartridge 135. In a preferred example, the cleaning agent is the same preservative-containing liquid medication contained in cartridge 135, which is filled into the chamber of the cleaning module during activation of the injection device. In an alternative embodiment, the cleaning agent is embedded in a porous plug. In another alternative, the cleaning agent is embedded in the matrix of a solid plug.

[0144] The shroud can be positioned in several locations. The initial position is defined by an initial angular position and a corresponding initial axial position. The locked position is defined by a locking angular position and a corresponding locking axial position. The unlocked distal position is defined by an unlocking angular position and a corresponding distal unlocking axial position. The movable shroud can be changed from the initial position to the locked position by a combination of rotation and proximal movement, in which the shroud is axially locked. In both positions, the needle tip is covered by the shroud and contained within the cleaning chamber assembly. During use, the shroud can be further rotated and moved proximally to the unlocked distal position, thereby exposing the tip. By further proximal movement of the shroud, a larger portion of the needle is exposed and injection can be performed. After injection, the shroud returns to the locked position, thereby cleaning the needle tip.

[0145] If, for some reason, it is necessary to reuse the needle without cleaning it, the cleaning module can be omitted.

[0146] Returning to Example 100 as illustrated. Figure 1B A perspective view of a cartridge holder 130 with a proximal extension tab 130.1 is shown, which is used to align and position the cartridge holder 130 relative to the housing 140 when inserted into the housing during assembly. Figure 1C An exploded view of a cleaning module 120 is shown, which includes a shield follower portion 120.1 and a movable portion 120.2. The movable portion includes a piston 122 and a piston rod 123, the piston rod having a radially extending arm 123.1 for cooperating with a needle interface 125 and the shield follower portion 120.1. The radially extending arm 123.1 includes a chamber housing engagement surface 123.2 for engaging the cleaning chamber 120 and an interface engagement portion 123.3 for engaging the interface 125. The needle follower portion 120.1 includes a cleaning chamber housing 121, which includes a distal tubular portion, an intermediate tubular portion, and a proximal tubular portion. These portions are integrally connected. A cap is provided at the distal end of the distal tubular portion, the cap covering the distal diaphragm onto the cleaning chamber housing. The outer surface of the middle tubular portion is provided with a cover protrusion 121.1 for snapping onto the cover tip 119 and an interface pushing protrusion 121.2. Figure 1CWindow W1 displays the same component in grayscale to better show the sloping surfaces and void sections. (As shown) Figure 2B As shown, an inclined proximal surface guide 121.3 is provided at the proximal end of the cleaning chamber housing 121 for guiding the piston rod 123 and piston 122 in the proximal direction in response to rotation. Window W3 in the figure supports an understanding of the mechanism for guiding or pushing the piston rod in the proximal direction. Rotating the piston rod 123 releases static friction, and further rotating the piston rod and pushing it into the inclined surface 121.3 of the cleaning chamber provides a first clearly defined axial movement. Figure 2D The image shows a cleaning agent reservoir 121.4, which is used to seal the distal end of the needle cannula under sterile conditions before use and under clean conditions during use.

[0147] Figure 1D A perspective view shows the needle cannula 124, the movable portion of the clean chamber 120.2 including a piston 122 and a piston rod 122, and the relative positioning of the cartridge engagement structure including a rigid portion 126 and a soft inner plug (not shown). The soft inner plug may be made of rubber and is adapted to seal the proximal end of the needle cannula under aseptic initial conditions before use. The rigid portion 126 provides support for the soft inner plug and is adapted to move the cartridge in a proximal direction in response to the movement of the interface 125 in a proximal direction once the needle has established a fluid connection with the drug in the reservoir. The soft plug can be punctured by the proximal tip of the needle cannula. The rigid portion 126 includes a radially extending interface engagement tab 126.1 and a radially extending cartridge engagement tab 126.2. The rigid portion also includes a distally extending blocking portion 126.3 for blocking further axial movement of the interface when the interface is in the proximal position. Figure 2D As seen, the blocking portion 126.3 is adapted to engage a small notch or circumferential slit 125.7 in the interface after a small relative rotation. The rigid portion 126 includes a proximal surface at the proximal end 126b, which, after assembly, abuts the distal surface of the cartridge. Thus, proximal movement of the rigid portion 126 of the cartridge engagement structure provides proximal movement of the cartridge.

[0148] Figure 1EA perspective view of the needle interface 125 is shown. Interface 125 includes a central disc portion 125.9 and a proximal extending skirt 125.11 extending from the disc portion. Skirt 125.11 is adapted to close the distal end of the cartridge 135 and the cartridge engagement structure including a rigid portion 126. Needle interface 125 also includes axially extending fingers 125.1 extending proximally from skirt 125.11 and adapted to cooperate with an axially extending rib 132 of the cartridge holder to allow relative axial movement between the interface and the cartridge holder and to prevent relative rotational movement. Two axially extending tubular portions (corner segments, which are curved like tubes but do not extend 360 degrees in the circumferential direction) or flanges 125.12 connecting the tubular portion 125.13 to the central portion 125.9 extend from the distal surface of the central disc portion 125.9. The tubular portions are adapted to surround the cleaning assembly 120. Figure 2D As best viewed, the gel tower 125.10 for securing the needle cannula is centrally located on the central disc portion 125.9. The interface 125 also includes a track disposed in the skirt 125.11 and adapted to guide the rotational movement of the cartridge engagement structure. The track includes a proximal axial portion 125.2 and a helical portion 125.3, the proximal axial portion providing an initial seat for the interface engagement tab 126.1 of the cartridge engagement structure, the helical portion for rotating the tab 126.1 and thus the rigid portion 126 of the cartridge engagement structure in response to guided proximal movement of the needle interface 125. The track also includes a distal axial portion 125.4, adapted to allow or guide relative axial movement of the tab 126.1 and thus the rigid portion 126 of the cartridge engagement structure at the end of rotation. Ribs 128 projecting in the negative radial direction, i.e., toward the center of the interface 125, are provided on the inner surface of the axially extending flange 125.12. Rib 128 includes an axially extending surface 128.1 flush with the edge of flange 125.12. The axially extending surface 128.1 provides a rotation stop for engaging piston rod 123. A circumferentially extending surface 128.2 is also provided at the distal end of rib 128 (see also...). Figure 1F Windows 3 and Figure 2D The circumferentially extending surface 128.2 provides an axial stop for engaging the push tab 121.2 of the chamber housing.

[0149] Figure 1F It shows Figure 1D The assembly of the modules shown, wherein Figure 1EThe interface 125 shown is in its unpackaged state, which is the initial state and prior to establishing a fluid connection between the needle cannula and the reservoir of the cartridge 135. It should be noted that an axial clearance is provided between the blocking portion 126.3 and the proximal surface of the central portion 125.9, allowing relative axial movement between the interface 125 and the rigid portion 126 of the cartridge engagement structure adjacent to the cartridge 135. Therefore, the clearance allows the needle cannula to be inserted into the cartridge in response to relative axial movement. Window W2 shows the entire assembly in grayscale. Window W3 shows the inner surfaces of the needle interface 125 with surfaces 128.1 and 128.2 and the guide 128.

[0150] Figure 2A A perspective view of a cleaning chamber housing 121 positioned in a needle interface 125 in its unpackaged state is shown. A tubular portion 125.13 surrounds the proximal portion of the cleaning chamber housing, and a radially extending interface push tab 121.2 rests on the distal support surface 127 of the interface in a first angular position. As explained in detail later in this application, upon activation, the needle shield is adapted to be guided in a proximal helical motion. Since the cleaning chamber housing is fixed to the needle shield, the push tab 121.2 performs a proximal helical motion relative to the rotationally fixed needle interface in response to activation. The needle interface is axially movable between a distal position and a proximal position. Since the needle interface is axially movably positioned on the cartridge holder 130, the push tab 121.2 of the chamber housing pushes the needle interface from the distal position to the proximal position in response to the needle shield moving from an initial position to a locked position. Furthermore, during the axial movement of the shield, the push tab 121.2 rotates together with the shield from the initial position to the locked angular position. In the locked angle position, the push tab 121.2 is angledly aligned with the notch 125.5 in the tubular portion 125.13 of the needle interface, and it is aligned with the axial stop surface 128.2. An axial clearance is provided between the push tab 125.2 and the axial stop surface 128.2. Between the initial position of the shroud and the locked angle position, the interface has moved proximal distance to engage the proximal end of the needle cannula 124 with the reservoir of the cartridge 135. The proximal movement of the interface further provides rotation of the cartridge engagement structure, whereby the tab 126.2 with the cam surface has been rotated and forced into the axial clearance between the distal surface of the distal end of the cartridge and the proximal surface of the circumferentially extending flange 134 (see [link to relevant documentation]). Figure 1ATherefore, the axial clearance between the cartridge and the circumferential flange 134 has become larger and the cartridge has been pushed in the proximal direction relative to the cartridge, and the neck engagement arm 133 has been deflected. In the locked position of the shield (corresponding to the proximal position of the interface 125), contact has been established between the blocking portion 126.3 of the cartridge engagement structure and the central interface portion 125.9. In this position, the cleaning chamber housing can be moved proximally until it abuts the stop surface 128.2. For the shield and shield follower portion 120.1 in the locked position, the shield follower portion is adapted to move with the shield to the distal unlocked position in a further proximal helical movement. For the shield and shield follower portion 120.1 in the distal unlocked position, the shield and shield follower portion can be further moved in a strictly proximal direction to deliver the dose through the needle.

[0151] Figure 2B A perspective view of a cleaning chamber piston rod 123 arranged in a cleaning chamber housing 121 is shown. As shown, an inclined surface 121.3 on the proximal surface of the housing 121 is axially aligned with the axially extending surface 123.2 of the piston rod. In this initial position, the surface 123.3 of the piston rod is arranged abutting the rotation stop 128.1 of the interface 125, and therefore cannot move counterclockwise relative to the interface. Initially, a circumferential clearance is provided between the inclined surface 121.3 and the engagement surface 123.2 of the housing, and in response to the proximal helical movement of the housing, the inclined surface 121.3 and the engagement surface 123.2 will approach and engage with each other to make contact. Thus, any static or adhesive friction between the plunger 122 and the housing 123 is overcome by relative rotation. In response to further rotation until the shroud is locked in the position, the inclined surface will generate a proximal directional force on the piston rod 123, thereby pulling the piston rod 123 and the plunger out of the cleaning chamber housing.

[0152] Because the plunger 136 in cartridge 130 is positioned abutting the piston rod 109, proximal movement of the cartridge relative to the cartridge holder (which is part of the housing assembly) will create overpressure within the cartridge. If the reservoir comes into fluid contact with the needle cannula, liquid will flow into the cleaning chamber. Additional features are provided to pull the plunger 122 out of the cleaning chamber housing 121 to overcome adhesive friction between the plunger and the chamber housing 121; however, when a fluid connection is established, pulling will also increase flow between the reservoir and the chamber housing 121.

[0153] Shell structure

[0154] Figure 3A and 3B A perspective view shows features arranged at the inner surface of the tubular shell structure 140 in an axial cut of the shell. Figure 3B In the middle, the axial cut is set in the plane containing the central axis of window 141, and in Figure 3A In this process, the injection has been rotated 90 degrees around the central axis, thus one of the windows 141c is visible behind the cutting plane. (As shown) Figures 3C to 3F As seen, the tubular shell structure 140 includes an outer tubular portion 143 and an inner tubular portion 154. In the illustrated example, the inner tubular portion 154 is integrally connected to the outer tubular portion. The outer tubular portion includes an outer surface having an outer diameter and an inner surface having an inner diameter. Similarly, the inner tubular portion includes an outer surface having an outer diameter and an inner surface having an inner diameter.

[0155] exist Figure 3A and 3B In the figures, the inner tubular portion 154 has been removed to clearly show the structure between the outer tubular portion 143 and the inner tubular portion 154. These figures show the distal guide structure of the housing 142 protruding from the inner surface. The distal guide structure 142 is adapted to guide the shield structure 110. These figures further show the intermediate guide structure of the housing 144c and the proximal guide structure of the housing 146c. The intermediate guide structure 144d, which is positioned with 180-degree rotational symmetry to 144c, is also shown. Figure 3D As shown in the diagram. The intermediate guide structure 144 also protrudes from the inner surface and provides an integral connection between the outer tubular portion 143 and the inner tubular portion 154. The intermediate guide structure is also adapted to guide the connector 170 and the shield structure 110. The proximal guide structure 146c forms a recess in the surface and is adapted to guide the connector 170. The distal guide 142c, intermediate guide 144c, and proximal guide 146c all have corresponding guides positioned in a rotationally symmetrical manner, but not all guides are shown or indicated. However, when referring, for example, to the distal guide 142, it can be any distal guide positioned in a rotationally symmetrical manner, and in the illustrated example, 142 can refer to one or both of the distal guides 142c and 142d.

[0156] The distal guide 142 includes a first axial portion 142.1, a first lateral portion 142.2, a second axial portion 142.3, a second lateral portion 142.4, and a third axial portion 142.5 providing a rotation stop. The intermediate guide includes a proximal lateral portion 144.1, a first axial portion 144.2, a distal lateral portion 144.3, and a second axial portion 144.4. The proximal guide includes a first axial portion 146.1, a first lateral portion 146.2, a second axial portion 146.3, a third axial portion 146.4, a ramp portion 146.5, and a flush portion 146.6. Together, the guide surfaces provide closed tracks that allow for cyclic guidance of the connector. The surfaces of the lateral portions extend in both radial and circumferential directions, the surfaces of the axial portions extend in both axial and radial directions, and the surface of the ramp portion 146.4 extends from the bottom of the recess toward the surface of the flush portion 146.5. The flush portion extends in both axial and circumferential directions and is flush with the inner surface.

[0157] Figure 3C Corresponding to Figure 3A The cut shown is such that the inner tubular portion 154 remains therein. It should be noted that the intermediate guide 144 is positioned in the annular space between the outer tubular portion 143 and the inner tubular portion 154. Figure 3D The perspective view shows the shell structure 140, in which tubular cuts have been made. The tubular cuts are made in a plane containing the inner surface of the shell structure, and the cuts remove the structure outside that plane. Therefore, only the structure on the inner surface is visible. Figure 3D An internal connection structure 140.3 for connection with the housing insertion portion 160 is shown. The connection structure 140.3 is adapted to position the insertion portion at an angle relative to the housing structure 140. Figure 3D Rib 140.1 is further shown, which, together with the radial surface of guide 142, supports the radial center position of the shield structure 110. A proximal-positioned rib 140.2 supports the radial position of the return spring 107. At the proximal end, a portion of the elongated housing structure 140 is shown proximally to rib 140.2. Figure 3E Corresponding to Figure 3B The cut shown in the figure has the inner tubular portion 154 left inside, as in 3C. Figure 3F The same perspective view as in 3D is shown, but the structure is viewed from a different angle, revealing details of the proximal guide 146c. The proximal guide 146c is considered as an edge surrounding the recess, but this edge is positioned in a plane with an inner surface. As seen, guides 142, 144, and 146 are arranged with double rotational symmetry. For the proximal guide 146c, the other rotated guide is not visible due to the angle of the perspective view.

[0158] therefore, Figures 3A to 3FTechnical details of the housing structure 140 according to the first embodiment are shown together. The distal guide 142 of the housing is adapted to guide the shield in both the rotational and axial directions along a connecting guide surface including a first axial portion 142.1, a first lateral portion 142.2, a second axial portion 142.3, and a second lateral portion 142.4. An intermediate guide is adapted to guide the connector in both the rotational and axial directions and includes a proximal lateral portion 144.1, a first axial portion 144.2, a distal lateral portion 144.3, and a second axial portion 144.4. As explained later, the first axial portion 144.2 of the intermediate guide 144 also provides a rotation stop for the shield 110 during injection. The proximal guide is adapted to guide the connector in the axial and rotational directions during a working cycle, and includes a first axial portion 143.1 providing a rotational stop and adapted to guide proximal axial movement, a first lateral portion 146.2 for guiding counterclockwise rotational movement, and a second axial portion 146.2 providing a rotational stop and adapted to guide distal axial movement together with a third axial portion 146.3. The proximal guide also includes a ramp portion 146.5 and a flush portion for guiding the connector back to the beginning of a working or dosing cycle.

[0159] Zero-point adjustment mechanism

[0160] Figure 4A and 4B A perspective view of a zero-point adjusting nut 106 according to an alternative embodiment of the present disclosure is shown. As shown, the distal side is... Figure 3A The middle part is visible at the distal end 106a, while the proximal side is... Figure 3B The adjusting nut 106 is visible at its proximal end 106b. It includes an internal thread 106.1 for engaging the external thread 109.1 of the piston rod 109 and an external thread portion 106.2 for engaging the internal thread 154.2 of the housing. In the illustrated embodiment, the external thread 106.2 is shown as two external thread portions, which are located proximal to the nut 106 and protrude from its outer surface. The external thread 106.2 can be made of any number of external thread portions. Alternatively, the threaded connection 106.2, 154.2 between the nut 106 and the housing can be replaced by a purely rotary guide.

[0161] Furthermore, ratchet arms 106.3 are provided on the outer surface of the adjusting nut 106. In the disclosed embodiment, two ratchet arms 106.3c and 106.3d are positioned with double rotational symmetry at the distal end 106a of the adjusting nut 106. Any suitable number of ratchet arms 106.3 can be provided. However, to increase the rotational stability of the adjusting nut 106, at least two rotationally symmetrical ratchet arms are preferred. Double rotational symmetry means that rotating 180 degrees around the central axis of the nut 106 will not change the appearance of the nut 106.

[0162] Figure 5 The perspective view shows an elongated shell structure 140 cut in half, thus revealing its inner surface. The elongated shell structure defines a distal end 140a and a proximal end 140b. Also shown, an inner tubular portion 154 adapted to support an adjusting nut 106 is provided on the inner surface of the elongated shell structure 140. Due to the cut, the inner tubular portion 154 is also shown as a half-tube. The illustrated embodiment is provided with axial teeth 154.3 adapted to engage with a ratchet arm 106.3 of the nut, which allows the adjusting nut 106 to rotate in only one direction. The permitted direction of rotation is clockwise, meaning that the ratchet arm 106.3 and the teeth 154.3 interface prevent the nut from rotating counterclockwise relative to the shell. The blocking or stopping direction of the adjusting nut 106 is the same as the direction of rotation of the piston rod because it advances in the distal direction during dosing. In this way, the adjusting nut will not accidentally shift during dosing.

[0163] In some embodiments, the inner tubular portion 154 is further provided with an internal thread 154.2, the direction of which causes the adjusting nut 106 to helically screw in the proximal direction when rotated in a permissible clockwise direction. Therefore, the threaded connections 106.2, 154.2 between the nut and the housing provide an additional gearing mechanism between the rotation of the adjusting nut 106 and the axial displacement of the rotationally fixed piston rod 109, which, for example, can be used to compensate for the relatively large pitch of the threaded connection between the adjusting nut 106 and the piston rod 109.

[0164] During the assembly of the injection device, it is desirable to minimize the distance, or air gap, between the piston rod 109 and the piston 136 inside the cartridge 135. Minimizing the air gap ensures that medication is dispensed from the reservoir in response to distal movement of the piston rod 109. If the gasket 104 is attached to the piston rod 109, as... Figure 6 The preferred embodiment disclosed herein aims to minimize the air gap between the distal surface of gasket 104 and the proximal surface of piston 136, such that when the injection device is arranged in a storage-permissible state, gasket 104 and piston 136 are abutted to each other, and the device is ready for delivery to the end user. In the following description of air gap elimination, reference will be made to the piston rod abutting the piston; however, the same considerations apply when eliminating the air gap between the piston and the gasket.

[0165] As the adjusting nut rotates relative to the housing structure during final assembly, the piston rod 109 is helically advanced in the distal direction until the piston rod 109 or washer 104 abuts the piston 136 inside the cartridge 135. In embodiments including threaded connections 106.2, 154.2 between the nut and the housing, the advancement of the piston rod relative to the housing is compensated for or counteracted by proximal movement of the adjusting nut relative to the housing.

[0166] The rotation of the adjusting nut is preferably accomplished using a special tool in the production line, the tool being adapted to engage the adjusting nut and transmit rotation to it. In a preferred example, the piston rod 109 is arranged to engage with the adjusting nut to provide a subassembly, which is then arranged in the inner tubular portion 154 of the housing. Subsequently, a computerized device is used to detect the relative position of the piston 136 in the cartridge 135 to be used in this particular injection device. Once the position of the piston 136 and the position of the piston rod 109 are obtained, the computer can determine the angular displacement required for the adjusting nut 106, arranged during assembly of the injection device, to position the piston rod abutting against the piston 136.

[0167] During assembly, the position of the proximal end of the piston rod 104 is thus adjusted by rotating the adjusting nut in the one-way interface with the inner tubular portion 154. It is important here that the adjusting nut can rotate in the direction that pushes the piston rod 109 into contact with the piston 136.

[0168] After assembly, with the piston rod 109 or washer 104 adjacent to the piston 136, it is impossible to further rotate the adjusting nut clockwise. Furthermore, in any assembled state, the nut 106 has no external interface with the external environment. Therefore, it is impossible to contact the outer surface with external tools or apply external torque to the nut.

[0169] The result of the above operation is that the adjusting nut 106 is self-locking relative to the housing structure, and it is not necessary to physically fix the nut 106 to the housing. Therefore, it is not necessary to weld or glue the nut component 11 to the housing.

[0170] Drive mechanism

[0171] Figure 6 A cross-sectional view of the proximal portion of the injection device is shown after zero-point adjustment between piston 136 and washer 104. Piston rod 109 is positioned at a proximal position indicating that the first dose has not yet been dispensed. Figure 7 A perspective view of the piston rod 109 is shown, with details of the external thread 109.1 and the axial track 109.2. Figure 8A and 8BThe drive tube 180 is shown in perspective views from different angles. These views show a tab 183c that projects from the outer surface and provides a structure for cooperating with the connector 170 during activation of the drive tube 180 and for relocking the shield structure 110 after a dose has been dispensed. The tab 183 includes a distally oriented surface 183.1 (a distal surface or distally oriented surface means that at least one component of the normal vector is oriented in the distal direction) and an axial portion 183.2 that provides an angularly oriented surface for cooperating with the connector 170. The views also show a helical structure 184c that projects from the outer surface and is adapted to axially block the connector in response to premature attempts to stop the dose during dosing. The tab 183 is positioned proximal to a lateral opening disposed in the helical structure 184. The views also show an axial surface 182c that is adapted to cooperate with the housing during activation and for providing a rotational stop that defines dose termination. Features 182, 183, and 184 will be explained in detail later in this application.

[0172] The drive tube 180 is provided with an inwardly projecting protrusion 180.2 that extends from its inner surface and is adapted to engage an axial track 109.2 of the piston rod 109. The piston rod 109 is adapted to be slidably arranged in the drive tube, thereby allowing relative axial displacement but preventing relative rotation. The drive tube 180 is provided with a ratchet arm 181c for engaging teeth 165.1 inside the tubular spring base 165, thereby forming a one-way ratchet interface such that the drive tube 180 rotates in only one direction to dispense the dose, which in the disclosed example is counterclockwise. The ratchet arm 181c thus prevents the piston rod 109 from rotating in a clockwise direction. In the illustrated example, the drive tube includes two ratchet arms 181c, 181d arranged with double rotational symmetry. In response to the counterclockwise rotation of the drive tube 180 and the piston rod 135, the ratchet arm 181 provides a dose-clicking sound during dispensing.

[0173] The engagement between the piston rod 109 and the drive tube 180 prevents relative rotation. Therefore, when the adjusting nut 106 is rotated clockwise during zero-point adjustment, the nut causes distal translation of the piston rod 109 because the drive tube is locked to prevent rotation in the clockwise direction.

[0174] In an embodiment according to this disclosure, the torque transmission drive spring 108 shown in FIG. 1 is arranged inside the drive tube 180 and is fixedly attached to the drive tube and spring base 165 at each end. The distal end includes a distal attachment 108.1 fixedly attached to the drive tube 180 and a proximal attachment 108.2 fixedly attached to the spring base 165. The drive spring is wound up or tensioned during assembly, thereby storing energy to rotate the drive tube with sufficient torque, thereby delivering multiple doses without further tensioning.

[0175] Incorporating a torsion spring into the drive mechanism offers several advantages. The inventors of this invention recognized that, in embodiments with a compression spring, the compression spring propels into the cartridge when it releases energy. If the injection device is designed to prevent the compression spring from advancing into the cartridge, the overall length of the device increases. Therefore, in length-limited constructions, the diameter of the spring is limited by the diameter of the cartridge. The inventors of this invention discovered that the torsion spring does not need to extend into the cartridge to limit the overall length of the device. Therefore, the torsion drive spring is not limited by the diameter of the cartridge or piston rod and is advantageous in length-limited constructions.

[0176] According to embodiments of this disclosure, the torsion-driven spring is arranged proximal to the cartridge and outside the piston rod 109. Therefore, the torsion-driven spring allows the spring to enclose a larger volume, thereby increasing the mass, i.e., the amount of spring material (e.g., steel). In other words, performance related to long-term storage and dosing can be improved due to the increased material or mass used. With the increased mass, the internal stress of the spring can be reduced, and / or the spring profile can be made flatter, thereby minimizing the dose-time variation between the first and last doses of the device. The inventors of the present invention have also discovered that if the maximum internal stress of the spring is reduced, the stress induced in the plastic component supporting the spring is also reduced, which is necessary to allow for long-term storage.

[0177] The inventors of this invention have also discovered that, in embodiments where the torsion drive spring is arranged inside the drive tube, the drive tube can be adapted to provide dose bounces and allows the number of dose bounces to be increased by increasing its diameter. Therefore, the number of dose bounces can be increased without extending the axial length of the device.

[0178] According to embodiments of this disclosure, the outer surface of the drive tube includes a dose-feeding structure suitable for providing dose-feeding sounds, such as a ratchet arm straddling teeth disposed on a surrounding structure. Alternatively, the ratchet arm is disposed on the surrounding structure and the teeth are disposed on the drive tube. The number of dose-feeding sounds increases as the circumference of the outer surface of the drive tube 180 increases with the diameter of the drive tube. In the case of a rotating drive tube, the number of dose-feeding sounds is determined as a relationship between the circumference of the drive tube and the distance between the dose-feeding structure, such as the distance between the teeth (number of dose-feeding sounds = 2 * pi * radius / distance between teeth). Therefore, the number of dose-feeding sounds can be increased by increasing the radius, but not by increasing the length of the spring and therefore not by increasing the length of the device. Conversely, to increase the number of dose-feeding sounds of a piston driven by a compression spring arranged in the piston, the length of the compression spring must be increased. In the case of a compression spring, the number of dose-feeding sounds is determined by dividing the axial extension of the spring by the distance between the teeth (number of dose-feeding sounds = axial extension / distance between teeth).

[0179] Furthermore, the inventors of this invention discovered that the energy required to release the trigger mechanism, i.e., the activation energy, is a function of the internal stress of the drive spring. Therefore, compared to similar designs based on compression springs, the activation of the dosing engine using a torsion-driven spring requires less force.

[0180] Furthermore, the inventors have found that embodiments incorporating a drive mechanism based on a torsion drive spring are easier to assemble than embodiments based on an equivalent compression drive spring. Torsion springs are relatively shorter than compression springs, and therefore easier to operate.

[0181] The rotating drive tube is readily adapted to work with an electronic dose capture device that records the rotating structure during quantitative drug administration, as described in WO 2019 / 110494 entitled “Drug delivery system with multipolar magnet and sensor system”.

[0182] Housing insertion part

[0183] Figure 9A and 9B Two different perspective views are shown of a housing insert portion 160, which is fixedly mounted at the distal end of an elongated housing structure 110 via an alignment structure and a snap-fit ​​structure 160c.3. The housing insert portion includes a cap mounting track 161. As shown, the cap mounting track 161c includes an axially extending track portion 161c.2 having a proximal end and a distal end, and a circumferentially extending track portion 161c.3 having a first end and a second end. A snap-fit ​​lock 161c.1 is positioned at the first end of the circumferential track, and the second end is connected to the proximal end of the axially extending track 161c.2, thereby forming a track for a bayonet coupling that cooperates with an inner protrusion of the cap 105. A rotation stop 161c.4 is also provided at the second end of the track 161c. The housing insert portion 160 also includes an axially extending slit 163c on its inner surface for cooperating with an axially extending rib 116c on the outer surface of the shroud (see Figure 161c). Figure 10A As will be explained later. The inner housing portion 160 also includes a proximal guide 162d for guiding the shroud 110. The proximal guide 162d shown extends in the circumferential direction and, in the counterclockwise direction, includes a helical portion 162d.1, a transverse portion 162d.2 with zero pitch, and an axial portion 162d.3. Alternatively, a threaded connection can be used for a bayonet connection.

[0184] Slender protective structure

[0185] Figure 10A and 10BA perspective view is shown of a cylindrical, elongated protective structure 110 to be arranged inside a tubular housing 140. Figure 10A The far side of the shield structure 110 can be seen in the image, and... Figure 10B The near side view can be seen in the middle. Figure 10C A portion of the shield structure is shown in a perspective side view. The elongated shield structure 110 includes a tubular portion comprising an outer surface having an outer diameter and an inner surface having an inner diameter. An axially extending rib 116c is arranged at the distal end and projects from the outer surface. This rib is adapted to cooperate with the inner rib of the cap 105 and to cooperate with a slit 163 on the inner surface of the housing insert portion 165.

[0186] The shield structure 110 also includes a stepped helical guide 112 disposed on its outer surface and adapted to cooperate with the proximal guide 162 of the housing insertion portion and the distal guide 142 of the housing. The stepped helical guide 112 is disposed in an annular space between the outer surface of the tubular portion of the shield structure 110 and the inner surface of the outer tubular portion 143 of the housing. The stepped helical guide includes a continuous protruding structure extending in both the axial and circumferential directions, and includes a proximal lateral protrusion, a proximal left-handed helical protrusion, an intermediate lateral protrusion, a distal left-handed helical protrusion, and a distal lateral protrusion. The continuous protruding structure includes a plurality of axially and circumferentially oriented surface portions providing guide surfaces (a circumferential surface or circumferentially oriented surface means that at least one component of the normal vector is oriented in the circumferential direction). The surface portions can be seen in FIG10 and are indicated by the following terms and reference numerals. The system comprises a proximal axial guide portion 112.1, a first proximal lateral guide portion 112.2, a second proximal lateral guide portion 112.3, a first proximal helical guide portion 112.4, a second proximal helical guide portion 112.5, a first intermediate lateral guide portion 112.6, a second intermediate lateral guide portion 112.7, a first distal helical guide portion 112.8, a second distal helical guide portion 112.9, a first distal lateral guide portion 112.10, a second distal lateral guide portion 112.11, and a distal axial guide portion 112.12. In this manner, guide portions 112.2, 112.4, 112.6, 112.8, and 112.10 provide the distal side of the stepped helical guide 112, and guide portions 112.3, 112.5, 112.7, 112.9, and 112.11 provide the proximal side.

[0187] The elongated shield structure 110 also includes a proximal guide 114 located at the proximal end of the shield structure 110. Figure 10A The far side can be seen in the middle, and... Figure 10BThe proximal side is visible above. The proximal guide 114 is adapted to cooperate with the connector 170 and the intermediate guide 144 of the housing. The proximal guide 114 extends in the axial and circumferential directions and includes a first left-handed helical portion 114.1, a first right-handed helical portion 114.2, a second right-handed helical portion 114.3, a second left-handed helical portion 114.4, a first axial portion 114.5, a first lateral portion 114.6, a second axial portion 114.7, a third axial portion 114.8, and a second lateral portion 114.9.

[0188] Guide portions 114.1-114.9 are all surface portions, and guide portions 114.1, 114.2, 114.3, 114.4, and 114.9 provide the proximal side of the proximal guide 114, while surface portion 114.6 provides the distal side, i.e., visible from both the proximal and distal positions, respectively. The proximal guide portions 114.1, 114.2, 114.3, and 114.4 are adapted to cooperate with the connector during activation operation.

[0189] The distal guide portion 114.6 of the proximal guide is adapted to cooperate with the connector in response to premature release of pressure on the shield during dosing, as will be explained in detail later in this application.

[0190] The third axial portion 114.8 is adapted to cooperate with the intermediate guide 144 of the housing and provide a rotation stop to prevent the shield from rotating further counterclockwise relative to the housing and during dosing. Similarly, the second lateral portion 114.9 provides an axial stop that cooperates with the intermediate guide 144 and prevents the shield from moving further proximally during dosing.

[0191] The proximal guide 114 includes a locking structure 115, which includes guide portions 114.4 and 114.5. In the illustrated embodiment, the locking structure 115 is part of a hook-like structure. As will be explained in detail later, the locking structure 115 is adapted to releasably lock to a corresponding hook-like structure of the connector 170 during dosing.

[0192] The cover also includes a snap-fit ​​arm 113 having an axial surface portion 113.1 that provides a rotation stop. In the initial state, the snap-fit ​​arm is radially compressed by the inner surface of the housing insertion portion 160.

[0193] connector

[0194] Figure 11A and 11BA perspective view of a connector 170 to be disposed within a tubular housing 140 and between an elongated shield structure 110 and a drive tube is shown. The connector 170 is adapted to establish a connection between the shield and the drive tube and to activate the drive tube 180. The connector 170 is further operatively connected to an auto-locking mechanism adapted to automatically relock the shield upon dose termination. The connector 170 includes a distal guide 172 adapted to cooperate with a proximal guide 114 of the shield. The distal guide 172 extends in both the circumferential and axial directions and includes a left-handed helical portion 172.1, a right-handed helical portion 172.2, a first axial portion 172.3, a transverse portion 172.4, and a second axial portion 172.5.

[0195] Guide portions 172.1-114.5 are all surface portions, with guide portions 114.1 and 114.2 providing the distal side of the distal guide 172, and surface portion 172.4 providing the proximal side. The distal guide portions 172.1 and 172.2 are adapted to cooperate with the proximal guide of the shield during activation. The proximal guide portion 172.4 is adapted to cooperate with guide portion 114.6 of the proximal guide of the shield in response to premature release from pressure on the shield during dosing, as will be explained in detail later in this application.

[0196] The return spring 107 pushes the connector in the distal direction. Therefore, in response to establishing engagement between the left-hand spiral portion 172.1 and the first left-hand spiral portion 114.1 of the proximal guide of the shield, or in response to establishing engagement between the left-hand spiral portion 172.1 and the second left-hand spiral portion 114.1 of the proximal guide of the shield, the left-hand spiral portion pushes the connector in the clockwise direction and pushes the shield in the counterclockwise direction.

[0197] The distal guide 172 includes a locking structure 171 comprising a left-handed helical portion 172.1 and a first axial portion 172.3. The locking structure 171 is part of a hook structure adapted to be releasably locked to a corresponding hook structure of the proximal guide 114 of the shield. A releasable lock is established between the hook structures when the second left-handed helical portion 114.4 of the shield's locking structure 115 abuts against the left-handed helical portion 172.1 of the connector's locking structure 171 under axial compression of the return spring 107. This causes the shield to be pushed counterclockwise, and the connector to be pushed counterclockwise, establishing abutment between the first axial portion 172.3 of the connector and the first axial portion 114.5 of the shield. To release the lock, in response to counterclockwise rotation of the connector, the friction established at the abutment between the two left-handed helical portions 114.4 and 172.1 must be overcome.

[0198] Connector 170 includes a tubular portion 170.1 having a full 360-degree circumference, and two axially extending tubular portions 170.2 formed by two cuts in the tube and thus providing only a portion of the circumference. Connector 170 includes an outer surface having an outer diameter and an inner surface having an inner diameter. Figure 12A and 12B As shown in the cross-sectional view of the proximal end of the injection device, the outer surface of the connector is arranged adjacent to the inner surface of the outer tubular portion 143 of the housing. The connector surrounds the inner tubular portion 154 of the housing and the drive tube 180. The inner diameter of the connector is larger than the outer diameter of the tubular portion of the shield structure 110, therefore the guide portions 172.1-172.4 are provided with shoulders protruding in the negative radial direction, which are used to achieve contact between the proximal guide 114 of the shield and the distal guide 172 of the connector.

[0199] The connector also includes an intermediate guide 174 adapted to cooperate with an intermediate guide 144 of the housing and thus control the position of the connector relative to the housing. The intermediate guide of the connector extends in both axial and circumferential directions and includes: a first axial portion 174.1 providing a rotation stop, a first lateral portion 174.2, a second axial portion 174.3, a left-hand helical portion 174.4, a third axial portion 174.5, a fourth axial portion 174.6, and a second lateral portion 174.7.

[0200] The intermediate guide 174 of the connector defines a blocking structure including a second lateral portion 174.7, which is adapted to prevent accidental axial movement of the connector and thereby prevent accidental activation of the drive tube 180.

[0201] The intermediate guide 174 further defines a seat or locking structure 173 including a first lateral portion 174.2 and a second axial portion 174.3, wherein the locking structure is adapted to provide rotational locking to prevent the connector from rotating and moving distally in the initial position. In the initial position, the connector 170 is in its distal position.

[0202] Connector 170 also includes an activation tab 178 disposed on an inner surface and extending radially from the inner surface in a negative radial direction. The activation tab 178 includes a first lateral portion 178.1 providing a proximal contact surface adapted to activate the drive tube 180. The activation tab also includes an axial portion 178.2 adapted to release an automatic relocking mechanism in response to a clockwise impact from the drive tube 180, and a second lateral portion 178.3 providing a retaining portion to prevent premature dose interruption in response to pressure on the shield.

[0203] The connector also includes a proximal guide in the form of a snap-fit ​​arm 176 adapted to cooperate with a proximal guide 146 of the housing. A circle surrounding the double symmetrically arranged snap-fit ​​arms 176c and 176d in their relaxed state defines a diameter larger than the outer diameter of the connector and larger than the inner diameter of the housing. Therefore, in response to arranging the connector 170 inside the outer tubular portion 143 of the housing and contacting the inner surface with the snap-fit ​​arm 176, the snap-fit ​​arm deflects in the negative radial direction. In this position, the snap-fit ​​arm 176 applies a radial force on the inner surface of the housing in the radial direction. The snap-fit ​​arm includes a first axial portion 176.1 for cooperating with axial guide portions 146.1 and 146.3 of the proximal guide of the housing, and an outer surface portion 176.2 extending in both the axial and circumferential directions adapted to cooperate with axial portions 146.4, ramp portions 146.5, and flush portions 146.6.

[0204] Proximal part of the injection device

[0205] return Figure 12A and 12B . Figure 12A and 12B A cross-section of the near end of the device is shown. Figure 12A A central cross-section including windows 141 (but they are located on the far side of the device, which is not visible in Figure 12) is shown. Figure 12B It shows relative to Figure 12A The central cross-section rotated 90 degrees. For example... Figure 12B As shown, the drive tube 180 includes four tubular portions: a first tubular portion 185, a second tubular portion 186, a third tubular portion 187, and a fourth tubular portion 188.

[0206] The first tubular portion 185 is also a distal tubular portion and is disposed within the inner tubular portion 154 of the housing. The distal tubular portion includes an outer tubular portion 185.1 that contacts the inner tubular portion 154. The outer tubular portion 185.1 is connected to the second tubular portion 186 and also includes an axial surface portion 182c adapted to cooperate with the housing during activation and to define dose termination. The outer tubular portion 185.1 also includes a distal helical surface portion 189c adapted to cooperate with a proximal helical surface portion of the inner tubular portion 154 of the housing during dosing (see also...). Figure 8AThe distal tubular portion 185 also includes an intermediate tubular portion 185.2 extending in the proximal direction. The proximal portion of the intermediate tubular portion 185.2 is surrounded by the second tubular portion 186 and thus defines an annular spring receiving space providing a distal base for the drive spring 108. The outer surface of the proximal portion of the intermediate tubular portion 185.2 defines a spring clip 180.2 for axially engaging with the drive spring 108 in response to axial insertion of the drive spring into the annular spring receiving space. The distal tubular portion 185 also includes an inner tubular portion 185.3 extending distally from the intermediate tubular portion and including an inwardly projecting protrusion 180.2 adapted to engage an axial track 109.2 of the piston rod 109.

[0207] The second tubular portion 186 includes protruding helical structures 184c and 184d on its outer surface. The second tubular portion 186 also includes an axial surface portion 182d arranged in a double rotational symmetry with the axial surface portion 182c, the axial surface portion being adapted to cooperate with the shell during activation and to define dose termination. The second tubular portion 186 also includes a distal helical surface portion 189d arranged in a double rotational symmetry with the distal helical surface portion 189c, the distal helical surface portion being adapted to cooperate with the proximal helical surface portion 157d of the inner tubular portion 154 of the shell during dosing (see also...). Figure 8A and 13A The protruding helical structure 184 protrudes from the outer surface of the second tubular portion 186 and extends to the inner surface of the connector 170. The helical structure 184 is adapted to axially block the connector in response to premature release of pressure on the connector during dosing, thereby blocking the axial movement of the activation tab 178 protruding inward from the inner surface of the connector 170.

[0208] The second tubular portion 186 and the third tubular portion 187 are surrounded by a return spring 107. Together with the inner tubular portion 165.2 of the spring base 165, the second tubular portion 186 and the third tubular portion 187 define an annular space that accommodates a portion of the drive spring 108. The fourth tubular portion 188 of the drive tube 180 is also a proximal tubular portion and includes a ratchet arm 181c for engaging the teeth 165.1 inside the outer tubular portion 165.3 of the spring base.

[0209] Activation mechanism

[0210] Figure 13A A perspective view of the inner tubular portion 154 of the housing and the drive tube 180 is shown, with the distal tubular portion 185 inserted into the inner tubular portion 154 and therefore not visible in the figure. The drive tube 180 is in its original position at this time. Before the first dose, the original position is also referred to as the starting position. After the first dose, the original position is also referred to as the dose termination position. Figure 13BThe diagram shows the cross-section along the indicator line CC and as seen from the proximal end. Figure 13C The cross-section CC is shown as seen from the far end.

[0211] Figure 13A The activation tab 178 on the inner surface of connector 170 is also shown. Figure 13A Only the tabs are shown; the rest of the connector is not shown. The connector with the activation tab 178 is positioned at its contact protruding tab 183, thus ready to transmit proximal movement to the drive tube, whereby the drive tube can be activated. The drive tube 180 is biased by a drive spring in the distal direction and counterclockwise. Figure 13A In the diagram, the drive tube is shown in the rest position, with the axial surface portion 182 adjacent to the axial surface portion 156 of the inner tubular portion 154 of the housing, thereby preventing counterclockwise rotation of the drive tube 180. In the rest position, the distal helical surface portion 182 also adjacent to the proximal helical surface portion 157 of the inner tubular portion 154 of the housing, thereby preventing distal movement of the drive tube 180.

[0212] Figure 13D The proximal end of the helical surface portion 157d.1, which defines the starting point of the helical dose track, and the distal end of the helical surface portion 157d.2, which defines the ending point of the helical dose track, are shown in detail. Similarly, the distal helical surface portion 189d defines the front point or front edge 189d.1 and the rear point or rear edge 189d.2. In response to moving the connector in the proximal direction, the activation tab 178, when arranged abutting the protruding tab 183, causes proximal movement of the drive tube 180. As a result, the front edge 189d.1 moves proximally along the axial surface portion 182d until it passes the proximal end of the axial surface portion and reaches the starting point 157d.1 of the helical dose track. Due to the counterclockwise bias of the drive tube 189, the drive tube 189 rotates in the counterclockwise direction, and due to the distal bias, the front edge 189d.1 is forced into contact with the helical dose track of the inner tubular portion 154. Subsequently, the drive tube with the leading edge 189d.1 travels along the helical dose track in a distal helical motion until it reaches the endpoint 157d.2. Note the small indentation at the endpoint 157d.2 of the helical dose track. However, since the indentation is smaller than the extension of the helical surface portion 189d, it does not affect the helical motion of the leading edge 189d.1. The same effect is achieved by the angular offset surface portion 182c and the distal helical surface portion 189c.

[0213] Cross-section of the injection device in the start-up state

[0214] Figure 14A and 14B A cross-section of the injection device 100 is shown. Figure 14A Corresponding to Figure 12AAnd it shows the central cross-section including window 141. Figure 14B It shows that in relation to Figure 14A The view shows the central cross-section of the device after rotating it 90 degrees. (Example) Figure 12B As shown, the drive tube 180 includes four tubular sections.

[0215] Figure 14 shows the device 100 in the activated state, with the shroud rotated to activate the device. The shroud moves proximally together with the needle assembly 120 in a helical motion. The proximal movement of the shroud causes proximal movement of the needle interface 125, thereby establishing a fluid connection between the needle 124 and the reservoir in the cartridge 135. The cartridge 135 and the plunger 136 have also moved proximally, and due to abutment against the gasket 104, the plunger has stopped its proximal movement, thereby filling the chamber of the cleaning assembly 120 (gasket 104 in...). Figure 6 (As shown in the figure, but not in Figure 14).

[0216] Operation of the device

[0217] Figure 15 is used to illustrate the working principle of the embodiments of this disclosure from the user's perspective, and the working principle will be described in more detail later with reference to Figure 16. Figure 15A User operation of the injection device 100 for administering the first dose is shown, and Figure 15B The procedure for administering a subsequent dose is illustrated, wherein the subsequent dose can be any fixed dose in a sequence between the first and last doses of a plurality of fixed doses. The injection device can be stored and delivered in a secondary package, and in the unpackaged state (A1), the injection device has been removed from the secondary package.

[0218] like Figure 15AAs shown, when the user wishes to administer the first fixed dose, the injection device is disassembled and thus provided in its unpackaged state (A1). The injection device is then activated by the user. Activation can be accomplished by grasping the main part 102 of the device with the right hand and the cap 105 with the left hand. The user then rotates the cap counterclockwise (for the example shown). The cap thus disengages from the cap latch 161.1 of the housing assembly and engages the needle shield, whereby the needle shield follows the rotation of the cap 105 until the cap 105 has rotated to the rotation stop 161.4. Due to the stepped helical guide 112 of the shield and the proximal guide 162 of the housing assembly, the needle shield undergoes a combined proximal and rotational movement in response to the user's rotation of the cap. Furthermore, through this initial rotation of the cap and the combined rotational and proximal movement of the needle shield, the needle cannula 124 pierces the diaphragm of the cartridge 135, and thus establishes fluid communication with the drug reservoir in the cartridge 135. Furthermore, during this operation, the cartridge 135 is moved proximally and pushed against the piston rod 109 or piston washer 104. When a fluid connection has been established with the cannula and the piston is positioned abutting the piston rod, the integrated needle is actuated, as will be explained in detail later. When the cap reaches the rotation stop, the injection device is positioned in the cap unlocked and activated state (B1), where the cap is unlocked and positioned for removal. The activated state is also shown in a cross-section in Figure 15.

[0219] In the next step, the user removes the cap 105, thereby placing the injection device in the cap-off state (C1), whereby the shield is locked to prevent axial translation.

[0220] Subsequently, the user manually rotates the needle shield counterclockwise, thereby arranging the device in the shield unlocked state (D1), where the shield is positioned and can be pressed proximally into the housing. Due to the guides 112, 162 between the shield and the housing, the shield undergoes a combined proximal and rotational movement when operating between the decapped state and the shield unlocked state. During the rotational unlocking movement of the needle shield, the needle shield exposes the cartridge inspection window 141 in the housing, thereby allowing inspection of the medication in the cartridge. Furthermore, the piston 136 is also visible in the observation window 141, and the position of the piston 136 relative to the fixed dose scale on the housing indicates the piston's movement during use, and thus indicates the remaining amount of the fixed dose in the reservoir. Figure 15A In the unlocked state (D1), piston 136 is positioned in the initial position and four doses remain in the reservoir. During proximal movement of the needle shield, the distal end of the needle tip protrudes through the septum at the distal end of the cleaning assembly 120, thereby releasing any excess pressure in the needle.

[0221] Subsequently, the user presses the needle sheath against the injection site, thereby displacing the sheath and connector 170 proximally against the force of the sheath return spring 107. The needle is then inserted into the patient's skin or subcutaneous layer. This action triggers the drive mechanism, delivering a fixed dose through the needle cannula in the dosing state (E1). Upon dose termination, the piston 136 has moved to the next position indicated by the remaining fixed dose scale on the housing, and the injection device can be removed from the injection site. The cut-out window of the remaining scale indicates the piston in the next position. It is useful to define sub-states for the corresponding dosing state as the piston 136 advances in the dosing state: the initial dosing state (E2.1) and the final dosing state (E2.2), where the piston is in the proximal pressurized position and the distal relaxurized position, respectively.

[0222] After the dosage has been administered, the user removes the device from the skin, thereby releasing pressure from the shield. Consequently, the shield moves distally due to the action of the return spring 107. The shield is subjected to distal movement, followed by a combined distal and rotational movement, due to the guides 112, 162 between the shield and the housing, and the guides 114, 142 between the shield and the connector 170, thereby automatically returning the shield to the relocked state (F1).

[0223] Subsequently, the user puts on the cap 105 via axial movement to place the device in the capped state (G1), which is Figure 15A The sequence shown represents the final state. The technical difference between the cap-unlocked and capped states within the same sequence is that the cartridge contains a smaller dose than the capped state.

[0224] Finally, rotate the cap to lock it into the housing assembly, thus entering the cap-locked state (A2). Figure 15B As shown in the image.

[0225] The difference between the cap-locked state (A2) and the box-out state (A1) is that the device has been activated. This is in Figure 15A and 15B As shown, the reason is that the shield moves proximally and rotates compared to its position in state (A1). Furthermore, in state (A2), the cartridge contains less dose than in state (A1). When the user rotates the cap to administer a subsequent dose, the cap is rotated to the cap-unlocked position without rotating the shield because the shield has already rotated to the activated but axially locked position. The difference between cap-unlocked state (B2) and cap-unlocked state (B1) is that in state (B2), the cartridge contains less dose than in state (B1), and corresponding differences can be observed between C1-C2, D1-D2…G1-G2, A2-A3, B2-B3…etc. This operating mode can continue until the last dose has been delivered, where it is impossible to trigger the drive mechanism again.

[0226] Detailed description of the operation of the device

[0227] Figures 16A to 16T Together, the relative and functional arrangements of the different structures during the state sequence of the injection device 100 are shown, and thus the operation of the device is shown in detail.

[0228] In embodiments of this disclosure, an injection device 100 for sequentially delivering multiple fixed doses includes: an elongated housing structure 140, a cartridge holder 130, and a housing insertion portion 160; an internally threaded housing; a shield including an elongated shield structure 110 and a needle tip 119; a needle interface 125 including a fixedly attached needle cannula 104; a cap 105 removably mounted on the housing and adapted to cover the distal end of the shield; a cartridge 135 having a movably arranged cartridge plunger 136; and a drive mechanism including a torsion drive spring 108, a drive tube 180, and a piston rod 109 having external threads for cooperating with the internal threads of the housing, the piston rod being arranged to connect to the plunger 136, and wherein the torsion spring is adapted to provide torque for rotating the drive tube 180 relative to the housing. The drive tube includes a ratchet mechanism that ensures rotation in the dosing direction and blocking in the non-dosing direction. The drive tube and piston rod are axially connected by a spline, thereby allowing relative axial movement and preventing relative rotation. The drive tube is adapted to advance the piston rod in response to rotation of the drive tube in the dosing direction, and the piston rod is adapted to advance the plunger 136 in the cartridge 135 to dispense a fixed dose due to its threaded connection to the housing. The drive mechanism is adapted to be activated by changing the drive tube from a distal position (where the drive mechanism is in a stationary mode) to a proximal position (where the drive mechanism is in a dosing mode). In the distal position, the drive tube is rotate-locked to the housing. In the proximal position, the drive tube is rotate-unlocked from the housing, and the torque provided can rotate the drive tube by a predetermined angle to dispense a fixed dose. In the stationary mode of the drive mechanism, the piston rod rotates and is axially locked, and the piston rod is rotate-locked to the housing via a splined connection to the drive tube 180, and axially locked via a threaded connection to the housing.

[0229] The torsion spring is pre-tensioned to deliver multiple doses during use without re-tensioning. The drive mechanism is adapted to change mode upon activation and, as explained later, to be repeatedly activated until the last dose has been expelled.

[0230] The cap can be positioned in an axially locked position and an axially unlocked position. The cap can be rotated between these two positions relative to the housing. For the cap in the axially unlocked position, it can be removed from the housing.

[0231] The needle interface 125 is movably disposed on the housing and movable relative to the housing between a distal position and a proximal position. The needle interface 125 is connected to the cartridge and rotate-locked relative to the housing. For the needle interface in the distal position, the proximal end of the needle cannula is disposed distal to the puncturable diaphragm of the cartridge. For the needle interface 125 in the proximal position, the needle cannula extends through the diaphragm and is positioned in fluid communication with the cartridge's reservoir. In response to moving the needle interface from the distal position to the proximal position, the needle cannula punctures the cartridge's diaphragm, causing the cartridge to move proximal distance relative to the housing and an axially locked piston rod.

[0232] The shield can be positioned in different locations. The initial position is defined by an initial angular position and a corresponding initial axial position. The locked position is defined by a locking angular position and a corresponding locking axial position. The unlocking distal position is defined by an unlocking angular position and a corresponding distal unlocking axial position. The unlocking proximal position is defined by an unlocking angular position and a corresponding proximal unlocking axial position. In the initial position, the shield is adapted to prevent axial and clockwise movement and to allow counterclockwise movement. In the locked position, the shield is adapted to prevent clockwise and axial movement. In this position, the shield is also adapted to allow counterclockwise rotation. In the unlocking distal position, the shield is adapted to prevent counterclockwise and distal movement of the shield and is also adapted to allow proximal movement. In the unlocking distal position, if the applied torque exceeds a predetermined threshold, the shield is also adapted to allow clockwise rotation. For the shield in the initial and locked positions, the needle tip is covered by the shield. In the unlocked position, the shield is adapted to move from the distal unlocked position (where the needle tip is exposed by the shield and pressure in the reservoir can be released) to the proximal unlocked position (where the needle tip extends further from the shield and can be inserted into the subject's subcutaneous layer). The user can manually operate the shield between the different positions. For the shield in the initial, locked, distal unlocked, and proximal unlocked positions, four different sets of angular and axial positions are defined: three different angular positions and four different axial positions.

[0233] The connector can be positioned in an initial position defined by an initial angular position and an initial axial position, wherein it is positioned to be rotationally locked to an intermediate guide 144 of the housing, wherein the intermediate guide 144 also prevents distal movement of the connector. The connector is biased in the distal direction by a return spring 107.

[0234] Figures 16A to 16T Together, the injection device 100 is shown in different states and intermediate arrangements, with the outer portions of the housing and the outer portions of the cap cut off to reveal some internal structures.

[0235] Figure 16AThe injection device in its unpackaged state is shown, and includes a cap 105, a shield structure 110, a housing insertion portion 160, a cartridge holder 130, a connector 170, a drive tube 180, a return spring 107, and a spring base 165. Figure 16A Reference figures are also provided for the proximal guide 162 of the housing insertion portion, the stepped spiral guide 112 of the shield, and the distal guide 142 of the housing. The user receives the device from the pharmacy and unpacks it from the secondary packaging. By unpacking, the user is provided with the injection device in its unpackaged state.

[0236] Figures 16B to 16E Together they showed Figure 16A The packaging condition shown is the same as Figure 16F The intermediate arrangement between the cap's unlocked state is shown. Figure 16B Reference numerals detailing the proximal guide 162 and the distal guide 142 are shown. The details are: a helical portion 162.1, a lateral portion 162.2, an axial portion 162.3, a first axial portion 142.1, a first lateral portion 142.2, a second axial portion 142.3, and a second lateral portion 142.4. Figure 16C and 16E Reference numerals showing details of the stepped helical guide 112 are provided. The details are: proximal axial guide portion 112.1, first proximal lateral guide portion 112.2, second proximal lateral guide portion 112.3, first proximal helical guide portion 112.4, second proximal helical guide portion 112.5, first intermediate lateral guide portion 112.6, second intermediate lateral guide portion 112.7, first distal helical guide portion 112.8, second distal helical guide portion 112.9, first distal lateral guide portion 112.10, second distal lateral guide portion 112.11, and distal axial guide portion 112.12. Figure 16D Reference numerals showing details of the proximal guide 114 of the shield are shown in Figure C. The details are: a first left-handed helical portion 114.1, a first right-handed helical portion 114.2, and a second right-handed helical portion 114.3. Figure 16C Reference numerals showing details of the distal guide 172 of the connector are shown. The details are: left-hand helical portion 172.1, right-hand helical portion 172.2, and first axial portion 172.3.

[0237] Outer packaging condition

[0238] The first user operation is to rotate the cap counterclockwise until it reaches the cap axial unlock position, thereby changing the cover from the initial position to the locked position, and thus the device changes from the unpacked state through a series of intermediate arrangements to the cap unlocked state (also known as the cover activation state).

[0239] More in detail, Figure 16A The arrangement of the injection device provided in its unpackaged state is shown. The cap 105 is arranged in an axially locked position, and the shroud is arranged in an initial position. A small circumferential clearance is provided between an axially extending rib 116 projecting from the inner surface of the cap and an axially extending rib 105.1 projecting from the outer surface of the shroud. A protrusion on the inner surface of the cap 105.2 is releasably held in the cap mounting track 161 by a snap-lock 161.1.

[0240] Figure 16B A first intermediate arrangement of the injection device is shown. Circumferential clearance has been eliminated by rotation, and abutment has been provided between the axially extending rib 116 of the cap and the axially extending rib 105.1 of the shroud. With further rotation, torque will be transmitted from the cap to the shroud. In the first intermediate arrangement, a circumferential clearance is provided between the first proximal helical guide 112.4 of the shroud and the helical portion 162.1 of the housing insertion portion, thereby allowing relative counterclockwise rotation between the shroud and the housing. Furthermore, only a small axial clearance is provided between the first proximal lateral guide portion 112.2 of the shroud and the lateral portion 162.2 of the housing, thereby preventing distal movement of the shroud beyond the axial clearance. Similarly, only a small axial clearance is provided between the second proximal lateral guide portion 112.3 of the shroud and the first lateral portion 142.2 of the housing, thereby preventing proximal movement beyond the axial clearance.

[0241] exist Figure 16C In the second intermediate arrangement of the injection device shown, the circumferential gap between the stepped helical guide 112 and the proximal guide 162 of the housing has been eliminated to provide abutment between the first proximal helical guide 112.4 of the shield and the helical portion 162.1 of the housing. In this position, a further circumferential gap is provided between the second proximal transverse guide portion 112.3 of the shield and the first transverse portion 142.2 of the housing, whereby the transverse portion 142.2 does not obstruct axial movement.

[0242] exist Figure 16D In the third intermediate arrangement of the injection device shown, the shield has been further rotated. In response to the rotation, the abutment between the helical guide portions of the shield and the housing provides rotational and proximal movement relative to the housing assembly. Thus, the stepped helical guide 112 has moved proximally along the helical guide portion 162.1. The stepped helical guide portion includes a front edge and a rear edge defined according to the direction of relative movement between the shield and the housing. Due to the relative movement, the area of ​​the abutment gradually decreases until the rear edge of the first proximal helical guide portion 112.4 reaches the proximal edge of the helical portion 162.1. At this minimum abutment position, the abutment between the stepped helical guide and the housing shifts from an abutment between helical portions to an abutment between transverse portions, thereby guiding the shield with pure rotation in response to further counterclockwise rotation. Figure 16DIn this configuration, the first proximal helical guide portion 112.4 of the shield and the helical portion 162.1 of the housing are adjacently disposed between the distal portion (near the rear edge) and the rear edge of the first proximal helical guide portion 112.4. Furthermore, as... Figure 16D As shown, the connector is arranged in an initial angular and axial position, where it is rotate-locked to the housing and prevents distal movement. The connector is biased in the distal direction by a return spring 107. Due to the proximal helical movement of the housing, an abutment in a resting position is established between the first left-hand helical portion 114.1 of the proximal guide of the housing and the left-hand helical portion 172.1 of the connector. In this position of the housing, a small axial clearance is provided between the second proximal helical guide portion 112.5 and the first lateral portion 142.2, thereby preventing pure axial movement in the proximal direction beyond the clearance.

[0243] exist Figure 16E In the fourth intermediate arrangement of the injection device shown, the shroud has been further rotated. The abutment between the lateral portion of the stepped helical guide 112 and the housing provides pure rotation. Therefore, the stepped helical guide 112 has moved counterclockwise along the lateral portion 162.2. The lateral guide portion 162.1 defines a first edge and a second edge, wherein the second edge is positioned counterclockwise relative to the first edge. The first intermediate lateral portion 112.6 includes a front edge and a rear edge defined according to the direction of relative movement between the shroud and the housing. Due to the relative movement, the area of ​​the abutment gradually decreases until the rear edge of the first intermediate lateral guide portion 112.6 reaches the second edge of the lateral portion 162.2. At this minimum abutment position, the abutment between the stepped helical guide and the housing shifts from an abutment between lateral portions to an abutment between helical portions, thereby guiding the shroud with helical motion in response to further counterclockwise rotation. Figure 16E In the illustrated arrangement, the first intermediate lateral guide portion 112.6 of the shield and the lateral portion 162.2 of the housing are abutted between the middle and rear edges of the guide portion. In the illustrated arrangement, a small axial clearance is provided between the second intermediate lateral guide portion 112.7 and the first lateral portion 142.2 of the housing, thereby restricting proximal movement.

[0244] Cap unlock, shield activation and lock status

[0245] In the cap unlocked and shield locked state, such as Figure 16FAs shown, cap 105 is arranged in the axially unlocked position, and shield is arranged in the locked position. The cap is positioned such that a protrusion 105.2 on the inner surface of the cap is located at the second end of the circumferential track portion 161.3, whereby the protrusion 105.1 is angularly aligned with the axial track portion 161.2 and is movable in the distal direction. The shield is arranged in the locked position, wherein an abutment is established between the stepped helical guide 112 and both the transverse portion 162.2 and the helical portion 162.1. In addition to the abutment between the first left-handed helical portion 114.1 of the proximal guide of the shield and the first left-handed helical portion 172.1 of the connector, an additional abutment is provided between the first right-handed helical portion 114.2 and the right-handed helical portion 172.2. Due to the proximal movement of the shield, the connector has moved proximally relative to the initial axial position and against the biasing force of the spring 107. The connector remains rotationally locked. To prevent clockwise rotation toward the outward orientation of the package, the axial surface portion 113.1 of the latch arm abuts the axial portion 162.3 of the housing. The latch 113 has been deflected from the compressed state in the radial direction behind the housing insertion portion 162.

[0246] Hat off

[0247] The second user operation is to pull the cap in the distal direction, thereby changing the device from the cap unlocked state to the cap removed state.

[0248] In the hat-off state, such as Figure 16G As shown, the cover has been removed from Figure 16F The main part 102 of the injection device shown is removed. The position of the shield relative to... Figure 16F The arrangement within remains unchanged and is still in the locked position. The shield is axially locked but allows for proximal helical movement guided by the abutment between the stepped helical guide 112 and the helical portion 162.1 of the housing.

[0249] Shield unlocked

[0250] The third user operation involves rotating the shield in the locked position counterclockwise until it reaches the unlocked position, thereby changing the device from the decapped state to the unlocked state through multiple intermediate arrangements.

[0251] Figure 16HA first intermediate arrangement is shown, in which the shroud has been rotated. In response to the rotation, the abutment between the helical guide portion of the shroud and the housing provides rotational and proximal movement relative to the housing assembly. Thus, the stepped helical guide 112 has moved proximally along the helical guide portion 162.1. The stepped helical guide portion includes a front edge and a rear edge defined according to the direction of relative movement between the shroud and the housing. Due to the relative movement, the area of ​​the abutment gradually decreases until the rear edge of the first distal helical guide portion 112.8 reaches the proximal edge of the helical portion 162.1. At this minimum abutment position, the abutment between the stepped helical guide and the housing shifts from an abutment between helical portions to an abutment between transverse portions, thereby guiding the shroud purely by rotation in response to further counterclockwise rotation. Figure 16H In this configuration, the first distal spiral guide portion 112.8 of the protective cover and the spiral portion 162.1 of the housing are abutted between the proximal portion (near the front edge) and the rear edge of the first distal spiral guide portion 112.8. Furthermore, in Figure 16H The position of the shield, as shown, establishes abutment between the first left-hand spiral portion 114.1 of the proximal guide of the shield and the first left-hand spiral portion 172.1 of the connector. In this position of the shield, a small axial clearance is provided between the second proximal spiral guide portion 112.5 and the first lateral portion 142.2, thereby preventing purely axial movement in the proximal direction beyond the clearance. Due to the proximal spiral movement of the shield, the connector adjacent to the shield has moved further in the proximal direction. Due to the rotational movement of the shield and the rotational locking of the connector by the intermediate guide 144 of the housing, the shield 110 rotates relative to the connector 170, thereby causing the right-hand spiral portion 172.2 to slide along the first right-hand spiral portion 114.2, and thereby disengaging the first left-hand spiral portion 172.1 from abutment with the first left-hand spiral portion 114.1 of the proximal guide of the shield.

[0252] from Figure 16H The first intermediate arrangement shown is to Figure 16K1 The shield is shown in the unlocked position, rotating with a proximal helical motion guided by the first distal helical portion 112.8, followed by a pure rotational motion guided by the first transverse portion 112.10. The arrangement for guiding the pure rotational motion is... Figure 16J As shown in the diagram. Through a proximal rotational movement of the shield 110 relative to the housing 140, the shield 110 moves relative to the connector 170, and the shield causes the connector to move relative to the housing. The right-hand helical portion 172.2 extends from the first right-hand helical portion 114.2 (…). Figure 16H Slide along the second right-handed spiral portion until the rear edge of spiral portion 172.2 reaches the proximal edge of the second right-handed spiral portion. Figure 16JWhen passing the rear edge, a new abutment is established between the second left-hand spiral portion 114.4 and the left-hand spiral portion 172.1 of the connector because the locking structure 171 of the distal guide of the connector moves to engage with the locking structure 115 of the proximal guide of the shield. Figure 16K1 When the left-hand helical portions 114.4 and 172.1 of the locking structures 115 and 171 abut under the biasing force of the return spring 107, they push the cover in a counterclockwise direction, thereby bringing the distal axial guide portion 112.12 into contact with the third axial portion 142.5 of the housing and stopping its rotation. A release locking mechanism is provided due to the biasing force and helical engagement. To release the lock, a torque exceeding the release threshold torque is required. As previously stated, the connector 170 has simultaneously moved relative to the housing. The connector 170 has been pushed out of the rotational lock with the intermediate guide 144 of the housing. Figure 16H Therefore, the rear edge of the second axial guide portion 174.3 has passed the distal edge of the first axial portion 144.2 of the intermediate guide, thereby transferring the first axial portion 144.2 from its abutment with the second axial guide portion 174.3 to its abutment with the left-hand spiral portion 174.4. The connector 170 is guided along the left-hand spiral guide portion 174.4 until the connector's snap-fit ​​arm 176 abuts the first axial portion 146.1 of the proximal guide of the housing, as shown. Figure 16K1 As shown in the image. Figure 16K2 The arrangement of connector 170 relative to drive tube 180 is shown, with the corner portions of the connector removed. The remainder includes an activation tab. The position of the activation tab 178 is indicated by a transverse portion 178.1 and an axial portion 178.2. As shown, the transverse portion 178.1 abuts the transverse portion 183.1 of the protruding tab 183 of the drive tube. Therefore, connector 170 is positioned to transmit force and proximal motion to the drive tube. Figure 16K3 The arrangement of Figure K2 is shown in K4 from the opposite side (rotated 180 degrees around the central axial axis). Also... Figure 16K3 As shown, when the shield is in the locked position, the connector has translated the drive tube a small distance in the proximal direction relative to its initial position, thereby exposing the proximal helical surface portion 157 (see Figure 157). Figure 16K3 ).exist Figure 13A The initial position of the drive tube 180 is shown in the figure. Figure 16K4 The injection device is shown in grayscale to provide a better impression of the surface orientation and the extension of different structures.

[0253] Dosage status

[0254] The fourth user operation is to push the shield in the proximal direction from the unlocked distal position until it reaches the unlocked proximal position, thereby changing the device from the shield unlocked state to the dosing state through multiple intermediate arrangements.

[0255] from Figure 16K1 The shield is shown in the unlocked state. Figure 16L1 In the first arrangement of the injection device in the metering state shown, the shield has been pushed axially from the unlocked distal position to the unlocked proximal position, thereby activating the tab 178 which has been pushed through the transverse opening in the outer helical structure 184. By the proximal movement of the shield, the shield has moved the interlocking connector 170. The connector adjacent to the drive tube 180 has moved the drive tube 180 from the distal rest position (where the drive tube is rotate-locked by the housing) to the proximal rotating position (where the drive tube will rotate relative to the housing). By the proximal movement, the torsionally tensioned drive spring 109 has been compressed and entered a compressed state. From the first arrangement of the device in the metering state ( Figure 16L1 The final diagram showing the arrangement of the drug in a quantitative dosing state. Figure 16N1 The drive tube has rotated 360 degrees during the distal helical motion, that is, a complete rotation, and returned to its initial position in the housing. Figure 13A (and 13N3), wherein the drive tube rotates and locks into the housing, thereby discharging a fixed dose. Through the rotational movement of the drive tube, the leading edge of the drive tube, having a distal helical surface portion 189, has been discharging from... Figure 16L3 The starting dosing position shown is located along the proximal spiral surface portion 157 of the inner tubular portion 154 of the casing in a counterclockwise direction. Figure 16M3 and 16M4 The intermediate shield is shown in the unlocked position, where the axial portion 183.2 impacts and abuts the axial portion 178.2 of the protrusion 178, as shown. Figure 16M2 As shown in the diagram. The drive tube, having its leading edge with a distal helical surface portion 189, continues its distal helical motion along surface portion 157 until it reaches the axial surface portion 156 of the inner tubular portion 154 of the housing. The drive spring is rotated by a torsionally pre-tensioned drive spring 108, and as the compressed drive spring 108 expands during release, the helical surface portion of the drive tube remains in contact with the helical surface portion 157 of the housing. Thus, the drive tube has returned to its initial position, corresponding to the position where the drive tube has reached the stop dosing position, and has prevented further counterclockwise rotation, as... Figure 13AAs shown in N3. In this position, in response to the release of axial and proximal directional forces on the shield when the device is lifted from the skin, i.e., the pressure on the shield tip 119, the activation tab 178 can move proximally through the lateral opening in the outer spiral structure 184. For the drive tube in the start-dose administration position, the intermediate shield unlock position, and the stop-dose administration position, three different sets of angular and axial positions are defined: three different angular coordinates and three different axial coordinates.

[0256] Activation of the automatic relocking mechanism

[0257] During the rotation of the drive tube 189 from the unlocked position of the intermediate shield to the stopped dosing position, the drive tube has supplied the connector with a torque exceeding the release threshold torque. Therefore, the connector's locking mechanism 171 has been released from the shield's locking mechanism 115, and the connector has rotated until it abuts against the rotation stop disposed in the housing. The automatic shield relocking mechanism is activated by releasing the locking mechanisms from each other.

[0258] During counterclockwise rotation, the rear edge of the left-hand spiral portion 172.1 moves slightly in the proximal direction along the second left-hand spiral portion until it has passed the proximal edge of the second left-hand spiral portion 114.1. Therefore, the connector has shifted from abutment with the left-hand spiral portion 114.4 of the housing to abutment with the right-hand spiral portion 114.3 of the housing; that is, a new abutment has been established between the right-hand spiral portion 172.2 of the connector and the second right-hand spiral portion 114.3 of the housing. Due to the right-hand spiral abutment, the connector is pushed counterclockwise under the biasing force of the distal orientation of the return spring 107. However, during the rotation of the connector, the connector arm 176 rotates along the first lateral portion 146.2 of the proximal guide of the housing until the abutment angle position between the axial surface 176.1 of the connector arm and the second axial portion 143.3 of the proximal guide of the housing. An optional and additional abutment is provided between the third axial portion 174.5 of the connector's intermediate guide and the first axial portion 144.2 of the housing's intermediate guide. This prevents further counterclockwise rotation of the connector 170. Due to the abutment between the distal axial guide portion 112.12 of the shroud's stepped spiral guide and the second axial portion 142.3 of the housing's distal guide, and possibly also due to the optional abutment between the third axial portion 114.8 of the shroud's proximal guide and the second axial portion 144.4 of the housing's intermediate guide, the shroud 110 in this unlocked proximal position is prevented from rotating clockwise, and the connector can only move the shroud in a purely axial direction.

[0259] Split dose prevention

[0260] During the activation of the drive tube 180, the connector has moved in the pure proximal axial direction until the activation tab 178 has reached... Figure 16L3 The position is indicated by a patterned rectangle. As previously described, through this movement of the connector, the drive tube 180 thus moves between a distal rest position (where the drive tube is rotate-locked by the housing) and a proximal rotational position (where the drive tube will rotate relative to the housing due to the torsion provided by the drive spring 108). Through this axial movement, the activation tab has moved through the lateral opening in the helical structure 184, and when the drive tube reaches the proximal rotational position, the drive tube begins to rotate, and the outer helical structure 184, protruding from the outer surface of the drive tube, rotates to laterally overlap with the activation tab 178, thereby holding the activation tab and the connector in the proximal position of the helical structure 184. The connector moves from... Figure 16L3 The starting dosing position shown in the diagram is rotated to move to... Figure 16N3 During the discontinuation dosing position shown, the activation tab 178 remains proximal to the helical structure 184 of the drive tube, thereby preventing dose fragmentation. If the pressure is released prematurely, i.e., before reaching the discontinuation dosing position, the connector and shield move in the distal direction until the distal oriented holding portion 178.3 of the activation tab 178 is axially abutted against the helical structure 184. Thereafter, if the axial proximal force on the shield is not re-established, the activation tab will slide along the helical structure 184 as the drive tube rotates to the discontinuation dosing position, thereby moving the activation tab in the purely distal axial direction through the transverse opening in the helical structure 184.

[0261] Figure 16M1 -M3 shows the same arrangement of the injection device 100. Figure 16M2 From and Figure 16M1 The device is shown at the same angle, but the corner portion of the connector has been cut off. Viewed from the relative position (rotated 180 degrees around the central axial axis). Figure 16M2 And M3. Figure 16M4 Displayed in grayscale Figure 16M3 The arrangement.

[0262] Figure 16N1 -N3 shows the same arrangement of the injection device 100. Figure 16N2 From and Figure 16N1 The device is shown at the same angle, but the corner portion of the connector has been cut off. Viewed from the relative position (rotated 180 degrees around the central axial axis). Figure 16N2 And N3.

[0263] Relocked status

[0264] The fifth user operation is to release the axial directional force on the shield by lifting the needle tip 119 from the skin, thereby moving the shield in the unlocked proximal position in the distal direction until it reaches the locked position, and thus the device has changed from the dosing state to the relocked state through a plurality of intermediate arrangements.

[0265] from Figure 16N1 The final arrangement shown is in the state of quantitative drug delivery. Figure 16P In the intermediate arrangement shown, the shield 110 has been moved axially from the proximal unlocking position to the distal unlocking position by the connector 170, thereby activating the tab 178, which has moved through the transverse opening in the outer spiral structure 184. Figure 16P The intermediate arrangement shown is to Figure 16Q In the intermediate arrangement shown, the connector has been rotated clockwise around the shield. From Figure 16Q The intermediate arrangement shown is to Figure 16S The relocked state shown indicates that the shield has been moved in the distal direction by connector 170 during clockwise rotation.

[0266] During distal movement, the right-hand helical portion 172.2 of the connector abuts the second right-hand helical portion 114.2 of the housing. Due to the helical abutment between the connector and the housing, the housing is pushed clockwise, thereby pushing the distal axial portion 112.12 toward the second axial portion 142.3 of the housing. Therefore, the housing is axially guided along the distal guide of the housing until the rear edge of the helical portion 172.2 has reached the distal edge of the second axial portion 142.2, thereby allowing the housing to rotate clockwise in response to further distal movement. Figure 16P The intermediate arrangement shown is illustrated. In the... Figures 16P to 16Q During clockwise rotation as shown in the intermediate arrangement, the stepped helical guide 112 slides between the first lateral portion 142.2 and the lateral portion 162.2, while the connector bias shield 110 slides along the proximal guide 114 of the shield. When the rear edge of the first distal lateral guide portion 112.10 reaches the edge between the lateral portion 162.2 and the helical portion 162.1 ( Figure 16Q The shield can move in a distal and rotational motion guided by the connector, which moves along the second right-hand helical portion 114.3 to a resting position adjacent to the first left-hand helical portion 114.1 of the proximal guide. Figure 16S ).

[0267] During the distal movement of the shield, the connector 170 has been guided in the distal direction by the first axial portion 144.2 of the intermediate guide of the housing, thereby preventing counterclockwise rotation, as in the final arrangement in the dosing state. Figure 16N1 )and Figure 16Pand 16Q The intermediate arrangement is shown in the diagram. When the leading edge of the left-hand spiral portion 174.4 reaches the proximal edge of the first axial portion 144.2, clockwise rotation of the connector is initiated. During distal movement, the connector arm or latching arm 176 has traveled along the axial guide portions 146.3 and 146.4 and along the ramp portion 146.4 to the flush surface portion 146.5, whereby the latching arm 176 has been radially compressed, as shown in the diagram. Figure 16Q As shown in the diagram, as connector 170 moves further in the distal direction, the left-hand helical portion 174.4 slides along the intermediate guide 144 of the housing, causing clockwise rotation until the rear edge of the helical portion 174.4 reaches the proximal edge of the first axial portion 144.2. In this position, the connector and the proximal guide of the housing are almost at rest, with the left-hand helical portion 172.1 abutting the first left-hand helical portion 114.1, and the connector arm has returned to abutting the first axial portion 146.1 of the proximal guide, as shown. Figure 16R As shown in the diagram. Therefore, the connector arm has been reset to its initial position and is ready to guide the connector during a new activation and dosing cycle. From Figure 16R The middle arrangement in Figure 16S In the relocked state, the connector moves to the distal end into the seat, wherein the first lateral portion 144.1 abuts the first axial portion 174.2, and wherein the axial portions 144.1, 144.2, 174.1 and 174.3 prevent rotation.

[0268] Cap status Cap locked status

[0269] The fifth user operation is as follows Figure 16T As shown, with the cap on, the protrusion 105.2 is inserted into the axial track portion 161.2, thereby allowing it to be rotated to position the device. Figure 15B The cap is shown in a locked state (the cap is not shown in conjunction with a detailed description of the operation). As... Figure 16T As shown, when the cap is rotated to the locked position, the axially extending rib is in a position that moves away from the protrusion 116. Therefore, when the cap is locked, there is no interaction between the cap 105 and the shield 110.

[0270] Second Embodiment

[0271] Figure 17 -26 illustrates a second embodiment of an injection device 200 for delivering multiple fixed doses according to the present disclosure. Figure 17 An exploded view of the injection device is shown, and Figure 18 A cross-sectional view is shown. Figure 18 Figure 23 shows further details of the individual structures and mechanisms. Figures 25-26 show in detail the interrelationships of the mechanical structures during operation.

[0272] Figure 17 The illustration shows a cap 205, a shield tip 219, and a shield follower portion 220.1 that also includes a movable portion of the cleaning module, the movable portion corresponding to the movable portion 120.2 in the first embodiment 1. Figure 17 The figure also shows a needle interface 225 with a needle cannula 224, a tubular elongated housing structure 240, and a housing cap portion 260 connected to the distal end of the housing structure 240. The figure also shows a tubular elongated needle guard structure 210, a cartridge holder 230, a cartridge 235, a connector 270, a guard return spring 207, a drive tube 280, a dose drive spring 208, a piston rod 209, and a spring base 265. The figure also shows a piston washer 204, which includes a ratchet arm and external threads, respectively for engaging the toothed ring and the internal threads on the inner surface of the piston rod 209, thereby allowing zero-point adjustment relative to the piston in the cartridge 235. Figure 18 A cross-sectional view of the injection device 200 is shown, with the injection device outside the packaging. The cross-section is cut through window 211 of the protective cover.

[0273] housing assembly

[0274] The injection device includes a housing assembly that provides a rigid frame with guides and connectors for guiding and connecting other components of the device. The housing assembly includes a housing cap portion 260, a tubular elongated housing structure 240, a cartridge holder 230 with a window 231, and a spring base 265. After final assembly, these structures are fixedly connected, and the housing assembly provides a reference frame for describing the relative movement and position of the other structures. The elongated housing structure 140 includes internal threads 254.3 for engaging the external threads of the piston rod.

[0275] The injection device 200 includes a drive mechanism and a triggering or activating mechanism. The drive mechanism includes a piston rod 209, a drive spring 208, and a drive tube 280, and these structures are operatively arranged within a housing for dispensing the dose. The triggering mechanism includes an elongated shield structure 210 and a connector 280, and these structures are operatively arranged within a housing for triggering the dose dispensing mechanism.

[0276] The tubular portion 254 includes an intermediate guide 244, which includes an outer axial portion 244.1 that is symmetrically arranged about a longitudinal axis at a first radial position and thereby defines a first diameter, and an inner axial portion 244.2 that is symmetrically arranged about a longitudinal axis at a second radial position and thereby defines a second diameter.

[0277] Needle shield assembly

[0278] The injection device also includes a needle shield assembly comprising a shield tip 219 and an elongated shield structure 210. The elongated shield structure 210 includes a window 211 for inspecting the medication. The elongated shield can be positioned in a first position overlapping with a cartridge holder window 231 and in a second position not overlapping, wherein a solid portion of the elongated shield structure covers the window 231 in the second position.

[0279] cartridge and cartridge holder

[0280] The cartridge holder 230 is adapted to receive the cartridge 235. The cartridge holder includes a window 231 for checking the drug in the cartridge 235. The cartridge 135 and the cartridge holder 230 are structurally and functionally similar to the cartridge 135 and cartridge holder 130 of the first embodiment, respectively.

[0281] Needle assembly

[0282] The needle assembly, including the needle interface 225 and the needle 224, is structurally and functionally similar to the needle assembly of the first embodiment.

[0283] cap

[0284] Cap 205 is adapted to be releasably mounted to housing cap portion 260. The cap includes an inner surface having protrusions adapted for engagement with a bayonet coupling track. The inner surface of cap 105 also includes axially extending ribs (not shown) projecting from the inner surface and adapted to transmit torque to the housing structure 110 via axially extending ribs 216 on the outer surface of the housing. Cap 205 is structurally and functionally similar to cap 105 of the first embodiment, except that cap 205 also encloses the main portions of the housing and cartridge.

[0285] Spring base

[0286] The spring base 265 is fixedly mounted to the housing structure 240 at the proximal end and is adapted to receive and support the compressible torque drive spring 108.

[0287] Drive spring

[0288] The drive spring 208 is pre-tensioned or coiled and positioned between the spring base and the drive tube 280. The drive spring is also adapted to generate torque on the drive tube, thereby discharging the medication. The drive spring includes a torsional section and a compressible section. The ability to drive the drive tube in the axial direction enables the dosage termination mechanism and allows the drive tube to be reset.

[0289] Return spring

[0290] A connector return spring 207 is positioned between a spring base 265 and a relocking tube 279 and is adapted to push the relocking tube in a distal direction. In the return arrangement, the relocking tube 279 abuts the housing 210, and the housing engages the connector, thereby allowing the housing 210 and connector 270 to return together with the relocking tube 279.

[0291] Cleaning components

[0292] The cleaning component is structurally and functionally similar to the cleaning component of the first embodiment.

[0293] Shell structure

[0294] Figure 19 A perspective view shows features arranged on the inner surface of the tubular shell structure 240 in an axial cut of the shell. (See figure) Figure 19 As seen, the tubular housing structure 240 includes an outer tubular portion 243 and an inner tubular portion 254. In the illustrated example, the inner tubular portion 254 is integrally connected to the outer tubular portion. The outer tubular portion includes an outer surface having an outer diameter and an inner surface having an inner diameter, wherein the outer tubular portion is adapted to accommodate a drive mechanism assembly and a relocking tube 279.

[0295] The housing structure 240 includes a guide structure comprising an axial surface portion 256 providing a sliding surface and a rotation stop, and a helical surface portion 257 providing a sliding surface suitable for guiding the drive tube 280 during metered drug delivery.

[0296] Figure 20 The inner tubular portion 254 is shown in detail in the perspective view, with the outer tubular portion 243 removed. The inner tubular portion includes a tubular drive tube engagement portion 254.1 for receiving the distal portion of the drive tube, and a tubular drive piston rod engagement portion 254.2 including threads 254.3 for threaded engagement of the piston rod 209. The piston rod engagement portion also includes a connector 254.4 for snap-fit ​​engagement with the cartridge holder 230.

[0297] Zero-point adjustment mechanism

[0298] like Figure 17 As seen, the piston washer includes external threads and a ratchet arm for cooperating with the threads and toothed ring on the inner surface of the piston, thereby achieving zero-point adjustment, similar to the method described with respect to the first embodiment.

[0299] Drive mechanism

[0300] The drive mechanism of the second embodiment has a structure and function similar to that of the first embodiment. In particular, the drive tube 280 is axially connected to the piston rod by a spline. Figure 23A and 23BThe drive tube 280 is shown in perspective views from different angles. As shown in FIG. 23, as a deviation from the first embodiment, the drive tube 280 of the second embodiment includes a closed guide rail 284 comprising a first lateral portion 284.1, a right-handed helical portion 284.2, and a left-handed helical portion 284.3. The lateral guide portion 284.1 includes a proximal orientation surface providing a connector seat, wherein the connector is seated before and after drive tube activation. The lateral portion also includes an abutment structure 283, which includes a distal orientation surface portion 283.1 providing an abutment surface for abutting the connector during activation. The right-handed helical portion 284.2 includes a distal surface providing an abutment surface for the connector in response to premature release of shield pressure, i.e., a split dose prevention feature. The left-handed helical portion 284.3 provides a ramp surface for rotating the connector upon dose termination, thereby initiating shield reset. For the first embodiment 100, the drive tube of the injection device 200 includes a guide structure, the guide structure including an axial surface portion 282 adapted to slidably engage an axial surface portion 256 of the housing in a rotationally locked arrangement, and a helical surface portion 289 for slidably engaging a helical surface portion 257 of the housing during metered administration.

[0301] The same consideration of incorporating a torsion spring into the drive mechanism in the second embodiment provides the same advantages as described in the first embodiment.

[0302] Slender protective structure

[0303] Figure 24 A perspective view of a cylindrical elongated shield structure 210 is shown. The proximal portion of the shield is disposed within a connector 270, which in turn is disposed within housing portions 240 and 260. The elongated shield structure 210 includes a tubular portion comprising an outer surface having an outer diameter and an inner surface having an inner diameter. An axially extending rib 216 is located at the distal end and projects from the outer surface. The rib is adapted to cooperate with the internal ribs of a cap 205.

[0304] The shield structure 210 also includes a radial guide 212 disposed at the proximal end and extending radially, thereby adapting the shield to cooperate with the connector 270.

[0305] The elongated shield structure 210 also includes a proximal guide 214 located at the proximal end of the shield structure 210. Figure 24The proximal side of the proximal guide 214 can be seen in the image. The proximal guide 214 is adapted to cooperate with the connector 270 and the relocking tube 279. The proximal guide 214 extends in both the axial and circumferential directions and includes a first transverse portion 214.1, an axial portion 214.2, a right-hand helical portion 214.3, and a second transverse portion 214.4. The proximal guide 214 also includes a cutout 214.5 providing rotational locking for locking the shield in the shield-activated state, in which it cannot return to its out-of-pack state. The cutout provides a right-hand helical guide portion 214.6. Guide portions 214.1-214.4 are all surface portions providing the proximal side of the proximal guide 214.

[0306] connector

[0307] Figure 22 A perspective view is shown of a connector 270 disposed within the tubular housing portions 240, 260 and between the elongated shroud structure 110 and the drive tube. The connector 270 is adapted to establish a connection between the shroud 210 and the drive tube 280, and is adapted to activate the drive tube 280. The connector 270 includes a distal guide 272 adapted to cooperate with a proximal guide 114 of the shroud. The distal guide 272 extends in the circumferential direction and includes a transverse surface portion 272.1 serving as a distal orientation surface.

[0308] The connector also includes a stepped helical track 274 for cooperating with the radial guide 212 of the housing. The stepped helical track includes a distal lateral portion 274.1, a distal helical portion 274.2, an intermediate lateral portion 274.3, a proximal helical portion 274.4, and a proximal lateral portion 274.5. Due to the helical portions of the stepped helical track, rotational motion of the housing 210 can be converted into proximal motion of the housing, and due to the lateral portions of the stepped helical track 274, distal directional forces on the housing can be transmitted to the connector 270, thereby allowing the housing to move distally. If the housing applies a distal force on the helical portions of the stepped helical track 274, the connector can move distally or both distally and rotationally.

[0309] Connector 270 includes a first tubular portion 270.1 having a complete 360-degree circumference and a second tubular portion 270.2 having two cutouts, whereby the remainder of the second tubular portion forms two axially extending tubular portions 276. The first tubular portion includes a stepped helical track 274, and the two axially extending tubular portions 276 include a distal lateral surface 272.1 forming a distal guide 272, a first axial surface providing the first axial guide 276.1, and a second axial surface providing the second axial guide 276.2, positioned clockwise relative to the first surface. A sheath may be disposed within the first tubular portion 270.1, with a radial guide 212 extending through the stepped helical track 274. The axially extending tubular portions 276 extend from the inner surface of the first tubular portion 270.1 in a proximal direction and therefore have a smaller diameter. A lateral surface portion 272.1 is disposed on the distal orientation surface of the axial extension tube portion 276, and since the diameter of the tube portion 276 corresponds to the diameter of the shield 210, the proximal guide 214 having a proximal orientation surface is adapted to cooperate with the lateral guide portion 272.1. The diameter of the axial extension tube portion 276 further corresponds to the diameter of the inner axial portion 244.2 of the intermediate guide, thereby allowing the axial extension tube portion 276 to cooperate with the inner axial portion 244.2. The connector 270 includes an outer surface having an outer diameter and an inner surface having an inner diameter. Figure 18 As shown in the cross-sectional view of the injection device 200, the outer surface of the first tubular portion 270.1 of the connector is arranged adjacent to the inner surface of the tubular housing cap portion 260. An axially extending tubular portion 276 surrounds the inner tubular portion 254 of the housing and the drive tube 280. The axially extending arm 276 is also adapted to cooperate with the intermediate guide 244.1 of the housing, thereby guiding the movement of the connector relative to the housing.

[0310] Connector 270 also includes an activation tab 278 disposed at the proximal end of the axially extending tube portion 270.2 and extending radially from its inner surface in a negative radial direction (i.e., toward the center of the tubular portion). The activation tab 278 extends into the closed guide rail 284 of the drive tube. The activation tab 278 includes a first transverse portion 278.1 providing a proximal oriented contact surface adapted to engage a distal oriented surface 283.1 of an adjacent structure in the transverse portion 284.1 of the closed guide rail, thereby enabling proximal movement and activation of the drive tube 280. The activation tab 278 also includes a proximal oriented surface portion 278.2 adapted to engage the distal oriented surface of the closed guide rail 284, thereby allowing the connector to be guided during dose cycling and preventing dose fragmentation in response to premature release of proximal pressure on the shield. A shield relocking mechanism is activated in response to guiding the proximal portion 278.2 of the activation tab along the left-hand spiral guide portion 284.3.

[0311] Relock tube

[0312] The relocking tube 279 includes a first tubular portion 279.1 and a second tubular portion having two slits, whereby the remainder of the second tubular portion forms two axially extending tube portions 279.2. The relocking tube includes an axially extending guide rail 279.4 extending a relatively small distance (e.g., 1 / 10 of the length of the relocking tube) from proximal to distal. The two axially extending tube portions 279.2 include an axial guide portion 279.5, a first lateral guide portion 279.6, a right-hand helical portion 279.7, and a second lateral portion 279.8. The axially extending tube portions 279.2 also include an axial portion 279.9, which provides a rotation stop and axial guide for the connector. The axially extending tube portions 279.2 extend from the inner surface of the first tubular portion 279.1 in the proximal direction, and therefore have a smaller diameter. Helical and lateral guide portions 279.6-279.8 are disposed on the distal orientation surface of the axially extending tube portion 279.2, and since the diameter of the tube portion 279.2 corresponds to the diameter of the shroud 210, the proximal guide 214 having a proximal orientation surface is adapted to cooperate with the helical and lateral guide portions 279.8-279.8. The diameter of the axially extending tube portion 279.2 further corresponds to the diameter of the inner axial portion 244.2 of the intermediate guide. The diameter of the first tubular portion corresponds to the diameter of the outer axial portion 244.1 of the intermediate guide. The axially extending guide rail 279.4 is adapted to cooperate with the outer portion 244.1 of the intermediate guide, thereby relocking the tube 279 between a distal position and a proximal position defined by the proximal end of the guide rail 279.4, thereby re-locking and axially guiding the tube 279 by rotation between these two positions. Figure 18 This is shown to be the axial clearance between the outer portion 244.1 and the proximal end of the track. The relocking tube 279 includes an outer surface with an outer diameter and an inner surface with an inner diameter. (As shown...) Figure 18 As shown, the outer surface of the first tubular portion 279.1 of the relocking tube is arranged adjacent to the inner surface of the outer tubular portion 243 of the housing, and a return spring is located between the spring base 265 and the proximal edge of the relocking tube 279, thereby allowing the relocking tube to be biased distally in response to proximal movement. The axial extension tube portion 279.2 surrounds the inner tubular portion 254 of the housing and can cooperate with the axial extension tube portion 270.2 of the connector.

[0313] Detailed description of the operation of the device

[0314] Figures 25A to 26B together illustrate the relative and functional arrangements of different structures during the state sequence of the injection device 200, thereby showing the operation of the device in detail.

[0315] In embodiments of this disclosure, an injection device 200 for sequentially delivering multiple fixed doses includes: an elongated housing structure 240, a cartridge holder 230 and a housing cap portion 260, an internally threaded housing, a shroud including an elongated shield structure 210 and a needle tip 219, a needle interface 225 including a fixedly attached needle sheath 204, a cap 205 removably mounted on the housing and adapted to cover a major portion of the shroud, a cartridge 235 having a movably arranged cartridge plunger or piston 236, and a drive mechanism including a torsion drive spring 208, a drive tube 280 and a piston rod 209, the piston rod having external threads for cooperating with the internal threads of the housing, the piston rod being arranged to connect to the piston 236, and wherein the torsion spring is adapted to provide torque for rotating the drive tube 280 relative to the housing. The drive tube includes ratchet mechanisms 281, 265.1, which ensure rotation in the dosing direction and blocking in the non-dosing direction. The drive tube and piston rod are axially connected by a spline, thereby allowing relative axial movement and preventing relative rotation. The drive tube is adapted to advance the piston rod in response to rotation of the drive tube in the dosing direction, and the piston rod is adapted to advance the piston 236 in the cartridge 235 to dispense a fixed dose due to a threaded connection with the housing. The drive mechanism is adapted to be activated by changing the drive tube from a distal position (where the drive mechanism is in a stationary mode) to a proximal position (where the drive mechanism is in a dosing mode). In the distal position, the drive tube is rotate-locked to the housing. In the proximal position, the drive tube is rotate-unlocked from the housing, and the torque provided can rotate the drive tube by a predetermined angle to dispense a fixed dose. In the stationary mode of the drive mechanism, the piston rod rotates and is axially locked, and the piston rod is rotate-locked to the housing via a splined connection with the drive tube 280, and axially locked via a threaded connection with the housing.

[0316] The torsion spring 208 is pre-tensioned to deliver multiple doses during use without re-tensioning. The drive mechanism is adapted to change mode upon activation and, as explained later, to be repeatedly activated until the last dose has been expelled.

[0317] The cap can be positioned in an axially locked position and an axially unlocked position. The cap can be rotated between these two positions relative to the housing. For the cap in the axially unlocked position, it can be removed from the housing.

[0318] The shield can be positioned in different locations. The initial position is defined by an initial angular position and a corresponding initial axial position. The disengagement position is defined by a disengagement angular position and a corresponding disengagement axial position. The engagement distal position is defined by an engagement angular position and a corresponding distal engagement axial position. The engagement proximal position is defined by an engagement angular position and a corresponding proximal engagement axial position. In the initial position, the shield is adapted to allow counter-clockwise movement. In the disengagement position, the shield is adapted to prevent clockwise movement and allow clockwise movement. The shield does not engage with the connector in the sense that proximal movement of the shield does not translate into proximal movement of the connector, thus the shield cannot activate the drive tube in this position. In the engagement distal position, the shield is adapted to prevent both counter-clockwise and distal movement of the shield, and is also adapted to allow proximal movement. In the engagement distal position, if the applied torque exceeds a predetermined threshold, the shield is also adapted to allow clockwise rotation. For the shield in the initial and disengagement positions, the needle tip is covered by the shield. In the engagement position, the shield is adapted to move proximally from the distal engagement position (where the needle tip is exposed by the shield and pressure in the reservoir can be released) to the proximal engagement position (where the needle tip extends further from the shield and can be inserted into the subject's subcutaneous layer). In this position, further proximal movement can be prevented by abutting the needle interface 125 to block the shield tip 119. The user can manually operate the shield between the different positions. For the shield in the initial position, disengagement position, distal engagement position, and proximal engagement position, four different sets of angular and axial positions are defined: three different angular positions and four different axial positions.

[0319] The connector can be positioned in an initial or first position defined by a first angular position and a corresponding distal position, wherein the connector is allowed to move to a proximal position, guided along the rotationally locked relocking tube 279 until the connector 270 encounters the axial stop or shield tip 219 abutting the interface 225 on the housing. Therefore, the connector can be further positioned in a second position defined by the first angular position and the proximal position. Furthermore, the connector can be positioned in a third position defined by the second angular position and a corresponding distal position, wherein the first and third positions are defined by the same axial position.

[0320] Figures 25A to 26B collectively illustrate portions of the injection device 200 arranged in different states and intermediate configurations, with the outer portion of the housing and the entire cap removed to reveal some internal structures. Each illustrated state is shown in the figure, where some internal components are concealed by connectors and relocking tubes, e.g., 25B1, and each illustrated state is shown in the figure, where a portion of the outer portion of the relocking tube and the outer portion of the connector has been removed, e.g., 25B3. Some illustrated states are also provided in grayscale; for example, 25B2 corresponds to 25B1 and 25B4 corresponds to 25B3.

[0321] Outer packaging condition

[0322] Figure 25A shows a portion of the injection device 200 in its unpackaged state, and illustrates the shield structure 210, cartridge holder 230, connector 270, drive tube 280, return spring 207, relocking tube 279, and spring base 265. Figure 25A1 Parts of the injection device are shown in black and white, and Figure 25A2 The same parts are shown in grayscale to better illustrate the different components of the structure.

[0323] Hat unlocked

[0324] The first user operation is to rotate the cap counterclockwise until it reaches the axial unlock position, thereby changing the cover from its initial position to the disengaged position, and thus changing the device from the unpacked state to the unlocked state, as shown below. Figure 25B1 As shown in B2. In the cap-unlocked state, the cap can move axially. The cap-unlocked state is also called the shield-activated state because the shield has activated the device, or the shield-disengaged state because the shield is not engaged with the connector to activate the device, or the inactive state because the shield cannot activate the drive mechanism. Compared to embodiment 100, the shield 210 in embodiment 200 does not need to be axially locked to the housing in this state, but since the shield does not engage the connector, axial movement cannot be transmitted from the shield to the connector, and the connector cannot be moved to activate the drive tube 280. Since the radial guide 212 of the shield engages the stepped helical track 274 of the connector 270, the radial guide 212 abuts the proximal surface of the distal helical guide portion 274.2 of the stepped helical track during the proximal helical movement of the shield from the initial position to the disengaged position. In the disengaged position, the radial guide rests on the intermediate transverse portion 273.4, where there is no proximal side on the track 274. During the proximal helical movement of the housing, the housing has moved the relocking tube 279 proximal against the biasing force of the return spring 208, and in the disengaged position, the axial extension 279.2 of the relocking tube has moved into the notch 214.5, thereby providing rotational locking. For the housing in the disengaged position, the right-hand helical portion 279.7 of the relocking tube abuts the right-hand helical guide portion 214.6 of the notch and the right-hand helical portion 214.3 of the proximal guide, and thus pushes the housing in the distal direction. The distal force is transmitted from the housing to the connector through the abutment between the radial guide 212 and the track 274, thereby biasing the connector also in the distal direction. Therefore, in the following state, the relocking tube 279, housing 210, and connector are biased distally. In Figure 25B, it appears that the housing does not extend to the spring base and is therefore not compressed. However, although the illustrated embodiment is somewhat imprecise, the housing is at least slightly compressed in this state. Otherwise, when rotated from top to bottom, the parts will rattle inside the device, and vice versa.

[0325] Hat off

[0326] The second user operation is to pull the cap in the distal direction, thereby changing the device from the cap unlocked state to the cap removed state.

[0327] Since the cap is not shown in Figures 25A-26B, Figure 25B1 B2 also shows the hat-off state.

[0328] Shield engagement or activation status

[0329] The third user operation is to rotate the cover in the disengaged or inactive position (when it cannot activate the drive mechanism) counterclockwise until it reaches the engaged distal position or the activated position, thereby changing the device from the cap-off state to the cover-unlocked state.

[0330] from Figure 25C1From the disengaged position to the distal engaged position shown in C2, the shield rotates with a proximal helical motion guided by the distal helical portion 274.4, followed by a pure rotational motion guided by the proximal lateral portion 274.5. During the proximal helical motion of the shield along the distal helical portion 274.4, the right-hand helical guide portion 214.6 of the cut and the right-hand helical portion 214.3 of the shield slide abutting against the right-hand helical portion 279.7 of the relocking tube, thereby pushing the rotationally locked relocking tube 279 in the proximal direction. During the pure rotational motion of the shield, the abutment between the helical portion 279.7 of the relocking tube and the helical portions 214.7, 214.3 of the shield only transfers to the abutment between the right-hand helical portions 214.3, 279.7, and then to the abutment between the second lateral portion 214.4 of the proximal guide and the first lateral guide portion 279.6 of the relocking tube. Because the abutment surfaces between the second lateral portion 214.4 of the shield and the first lateral portion 279.6 of the relocking tube extend in a direction perpendicular to the biasing force of the return spring, the abutment provides a static position for the relocking tube 279 and the shield 210. Due to the biasing force and abutment between the lateral portions 214.4 and 279.6, a releasable locking mechanism is provided between the shield 210 and the relocking tube 279. To release the lock, a torque exceeding the release threshold torque is required. During the helical movement of the shield, the first lateral surface portions 214.1 and lateral surface portions 272.1 of the proximal guide of the shield abut, and during pure rotational movement, the shield slides relative to the connector until the axial portion 276.1 of the axial extension 276 abuts against the axial portion 214.2 of the proximal guide. Therefore, releasing the lock and thereby establishing abutment between the sheath and the spiral portions 214.3, 279.7 of the relocking tube will also disengage the sheath and the transverse portions 214.1, 272.1 of the connector. Another axial portion 276.2 of the connector's axial extension tube portion 276 is rotated-locked counterclockwise against the axial portion 279.9 of the rotationally locked relocking tube, which is slidably arranged with an intermediate guide 244 engaged in the axial track 279.4. The connector's activation tab 278 is seated in the transverse portion 284.1 of the closed guide track in the drive tube. In the distal engagement position, the sheath is adapted to move the connector in the proximal direction to activate the drive tube.

[0331] Dosage status

[0332] The fourth user operation is to push the shield in the distal engagement position in the proximal direction until it reaches the proximal engagement position, thereby changing the device from the shield unlocked state to the dosing state. The dosing state is shown in the arrangement shown in Figures 25D to 25E.

[0333] from Figure 25D1From the distal position of the shield engagement shown in D2 to the proximal position, the shield moves with a proximal and purely axial movement guided by a relocking tube traveling along the intermediate guide 144. During the proximal movement of the shield, the relocking tube 179 engaged by the shield translates proximally to further compress the return spring 208, and the connector engaged by the shield translates proximally, thereby activating the tab 278 to engage the proximal surface of the lateral portion 284.1 of the closing guide rail, and wherein the drive tube also translates proximally. Thus, the drive tube has moved from the distal position (where the drive tube is rotated-locked to the housing) to the proximal position (where the drive tube is rotated-unlocked from the housing). Figure 25D2 As shown, the torque provided by the drive spring 207 has rotated the drive tube, thereby activating the tab to slide out of the lateral portion 284.1 and into the right-hand helical portion 284.2 of the closed guide rail. Figure 25D also reveals the axial portion 257 of the inner tubular portion 254 adjacent to the housing (see Figure 25D). Figure 19 The axial portion 282 of the drive tube and the helical portion 256 of the housing adjacent to the helical portion 289 of the drive tube (see Figure 23).

[0334] Figure 25E shows another arrangement following the arrangement in 25D in the dosing state, where the drive tube 180 has been further rotated during dosing, thereby activating the tab 278 arranged proximally at the right-handed helical portion 284.2, which is adjacent to the portion about to change from right-handed to left-handed helical portion 284.3. As in the previous state, the connector abuts the axial portion 114.2 of the proximal guide of the shield, and the first lateral guide portion 279.6 of the relocking tube abuts the second lateral portion 214.4 of the proximal guide of the shield to transmit axial distal force from the relocking tube 279 through the shield 210 to the connector 270.

[0335] Activation of the automatic relocking mechanism

[0336] When the drive tube stops rotating upon reaching dose termination, the proximal portion 278.2 of the activation tab 278 disengages from the right-hand helical track, thus no longer preventing the connector from moving in the distal direction. Since the drive tube no longer prevents axial movement of the connector, the connector will move axially and rotate in the distal direction in response to pressure released from the shield, thereby engaging with the left-hand helical portion 184.3 of the drive tube. Therefore, the automatic relocking mechanism is activated.

[0337] Split dose prevention

[0338] During the dosing cycle, the activation tab 278 engages in the closed guide rail 284. Therefore, in response to lifting the shield from the skin, the activation tab will be blocked by the first transverse portion 284.1 or the right-hand spiral portion 284.2 of the guide rail 284 before the dose is completed, and the drive tube will continue to rotate until the dose is completed. Upon completion of rotation, the connector will be pushed distally along with the activation tab and the shield, but this prevents dose interruption or splitting, thereby ensuring the correct administration of the next dose. If the shield extends to the distal position, the needle tip will be placed in the clean chamber, potentially creating overpressure in the clean chamber. Overpressure could unintentionally interrupt dosing.

[0339] Relocked status

[0340] The fifth user operation is to release the axial directional force on the shield by lifting the needle tip 219 from the skin, thereby moving the shield in the proximal engagement position in the distal direction until it reaches the disengagement position, thereby changing the device from the dosing state through the intermediate arrangement shown in FIG25F to the disengagement state or non-actuated state shown in FIG25G.

[0341] Automatic relocking mechanism

[0342] Figure 25F shows an intermediate arrangement between the dosing state and the disengaged state shown in Figure 25G, where the drive tube has been rotated to abutment the axial portion 257, thereby completing the dosing. During the rotation of the drive tube, and in response to the release pressure from the shield, the activation tab 278 has moved to abutment the left-hand helical portion 284.3, and due to compression from the return spring 207, the activation tab 278 has been pushed to move along the left-hand helical track, thus causing the connector 270 to rotate and move axially to the second angular position and distal position. The force from the compression spring is transmitted from the relocking tube through the shield to the connector. During the rotation of the connector, the shield has rotated due to the abutment between the connector and the axial portion 214.2 of the proximal guide of the shield. Due to the rotation of the shield, and when the relocking tube is rotated to lock, the abutment between the shield and the relocking tube has shifted to the abutment between the right-hand helical portion 214.3 of the shield and the right-hand helical guide 274.7 of the relocking tube. The helical abutment surface allows the axial movement of the relocking tube 279 to be converted into rotational movement of the shield, and when the relocking tube is biased distally, the relocking tube moves distally and the shield rotates to the disengaged position, thereby disengaging the first lateral portion 214.1 of the shield's locking structure 215 from abutment with the lateral portion 272.1 of the distal directional lateral guide portion 272 of the connector. Since the two lateral portions 214.1, 272.1 are lateral, they can be forced to slide apart in response to the application of relative rotation.

[0343] Cap status Cap locked status

[0344] The fifth user operation involves putting on a cap (not shown) for the injection device 200, by inserting the protrusion on the inner surface of the cap into the axial track portion on the housing, thereby allowing the cap to be rotated to position the device in the cap-locked state. The cap-locked state of the injection device 200 is not shown. When rotated back to the locked state, the cap 205 does not engage with the shield, and therefore does not push the shield toward the initial position.

[0345] Figures 26A and 26B illustrate two arrangements for applying a second or more doses without rotating the connector back to its first position. When the relocking tube is moved to its distal position, the connector 270 can remain in a third position with a second angular position (e.g., Figure 25G2 As shown in Figure 25B, or when the radial guide slides distally along the proximal helical guide 274.4, the shield 210 can force the connector to rotate to a first position with a first angular position. In the latter case, the new dose will begin from the arrangement shown in Figure 25B. In the first case, the new dose will begin from... Figure 25G2 The arrangement shown in Figure 26A begins and continues to the arrangement shown in Figure 26A, where the shroud pushes the relocking tube in the proximal direction until the axial portion 214.2 of the shroud abuts the axial extension 270.2 of the connector. In response to further rotation, the connector is pushed back to a first position with a first angular position, as shown in Figure 26. From here, the next dose continues, as described in Figure 25C.

[0346] Additional Examples

[0347] The additional alternative embodiments described are not shown separately and no reference numerals are provided. However, the features of the alternative embodiments correspond to the features of the illustrated embodiments, thereby providing one or more functions similar to or the same as the features of the illustrated embodiments.

[0348] In an alternative embodiment, a drug delivery device is provided for sequentially delivering a predetermined plurality of fixed doses of drug, wherein the drug delivery device comprises:

[0349] - Housing components,

[0350] - A drive mechanism including a drive tube, wherein the drive mechanism is adapted to sequentially deliver a predetermined plurality of doses, and,

[0351] - An activation mechanism for activating the drive mechanism.

[0352] The drive mechanism includes pre-tensioned torsion drive springs 108 and 208, which store an initial amount of energy and are adapted to rotate the drive tube. Each activation of the drive mechanism and the completion of the drive tube dose sequence reduces the amount of energy stored in the drive springs, and the initial amount of stored energy, which is the energy stored before the first activation, is sufficient to deliver the predetermined plurality of fixed doses.

[0353] Therefore, a drug delivery device is provided for delivering a predetermined plurality of fixed doses without requiring the drive mechanism to be ready for activation or tensioned between doses, because the energy stored before the first activation is sufficient to deliver the predetermined plurality of fixed doses. The fixed-dose drug delivery device according to the invention is suitable for delivering doses of the desired volume multiple times. The predetermined quantity is determined by dividing the total amount of drug by the desired volume of the fixed dose.

[0354] In an alternative embodiment:

[0355] -The housing assembly further includes a guide structure, which includes a stop and activate guide portion and a drive guide portion;

[0356] - The drive tube is adapted to be guided along the stop and activate guide portion to activate the drive mechanism, and along the drive guide portion to deliver a fixed dose, and guided to the stop and activate guide portion, wherein dosing is stopped, thereby the drive tube is adapted to be guided in response to the execution of a drive tube dosing sequence including activation, dosing, and stopping dosing;

[0357] - The drive mechanism further includes a piston rod operably connected to the housing assembly and the drive tube.

[0358] The activation mechanism is adapted to move the drive tube along the stop and activation guide portion from a first axial position to a second axial position in a first axial direction, thereby activating the drive mechanism.

[0359] The drive guide portion corresponds to the spiral portions 157 and 257 of the first and second embodiments, and the stop and activate guide portion corresponds to the axial portions 156 and 256 of the first and second embodiments. The drive tube, torque drive spring, and piston rod correspond to the drive tube 180 and 280, the torque drive spring 108 and 208, and the piston rod 109 and 209.

[0360] It appears that the volume of the fixed dose is determined by the housing and the guide of the drive mechanism. Therefore, the fixed-dose drug delivery device according to the invention is suitable for delivering the required volume of dose multiple times. Similarly, with the fixed-dose drug delivery device according to the invention, the fixed dose can only be adjusted by modifying the drive mechanism and the guide of the device.

[0361] The drive mechanism is also adapted to bias the drive tube in a second axial direction opposite to the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube 180, 280 along the drive guide portion 157, 257 to the stop and activate guide portion 156, 157 in response to activation of the drive mechanism, thereby delivering a fixed dose of the predetermined plurality of fixed doses, and wherein the drive tube is operatively positioned to be guided along the stop and activate guide portion to deliver a subsequent fixed dose of the plurality of fixed doses.

[0362] In an alternative embodiment, the housing further includes an internal thread, and the piston rod further includes an external thread for threading the internal thread of the housing assembly, wherein the drive tube is axially connected to the piston rod by a spline, thereby allowing the drive tube to be axially moved and rotated relative to the drive tube for locking, thereby allowing the piston rod to be operatively connected to the housing assembly and the drive tube.

[0363] In an alternative embodiment, the torsion drive spring is compressed, thereby adapting the drive mechanism to bias the drive tube in the second axial direction.

[0364] In an alternative embodiment, the drug delivery device includes an axially movable spring base, wherein the drive mechanism includes a compression return spring located between the axially movable spring base and the housing, whereby the torsion drive spring and the return spring are connected in series, thereby adapting the drive mechanism to bias the drive tube in the second axial direction. The spring base corresponds to spring bases 165 and 265 in the first and second embodiments.

[0365] In an alternative embodiment, the drug delivery device is adapted to deliver drug at a distal end, wherein the drug delivery device includes a central axial axis defined between the distal and proximal ends. The drug delivery device also includes a slidably arranged spring base, wherein a torsion spring is disposed between the spring base and the drive tube. During activation and dosing, the drive tube is positioned such that the component of the central axial axis in the direction opposite to the direction of gravity is the second axial direction, thereby biasing the drive tube distally. The drive mechanism is thus adapted to bias the drive tube in the second axial direction, i.e., gravity is used as the biasing force. The spring base corresponds to spring bases 165 and 265 in the first and second embodiments.

[0366] In an alternative embodiment, the torsion drive spring is arranged between the drive tube and the housing assembly.

[0367] In an alternative embodiment, the housing assembly includes a fixed spring base, wherein one end of the torque-driven spring is attached to the fixed spring base. The spring base corresponds to spring bases 165 and 265 in the first and second embodiments.

[0368] In an alternative embodiment, the stop and activate guide portions of the guide structure are axial portions, and the drive guide portion of the guide structure of the housing assembly includes a helical portion. The axial portions correspond to axial portions 156 and 256 in the first and second embodiments, and the helical portions correspond to helical portions 157 and 257.

[0369] In an alternative embodiment, the stop and activate guide portions of the guide structure are axial portions, and the drive guide portion of the guide structure of the housing assembly includes a transverse portion. The axial portions correspond to the axial portions 156, 256 of the first and second embodiments, and the transverse portions correspond to the helical portions 157, 257.

[0370] In an alternative embodiment, the stop and activate guide portions of the guide structure are axial portions, and the drive guide portion of the guide structure of the housing assembly includes a stepped portion, the stepped portion comprising a portion from a first group including lateral and helical portions and a portion from a second group including radial, helical, and axial portions. The axial portions correspond to axial portions 156, 256 in the first and second embodiments, and the stepped portions correspond to helical portions 157, 257.

[0371] In an alternative embodiment, the drive tube includes corresponding guide structures 182, 189, 282, and 287 adapted to cooperate with the guide structures 156, 157, 256, and 257 of the housing assembly. The corresponding guide structures of the drive tube correspond to the corresponding guide structures 182, 189, 282, and 287 of the drive tubes in the first and second embodiments. The guide structures of the housing assembly correspond to the guide structures 156, 157, 256, and 257 of the housing assembly in the first and second embodiments.

[0372] In an alternative embodiment, the guide structure of the drive tube includes an axial portion and a helical portion. The axial portion corresponds to axial portions 182 and 282 in the first and second embodiments, and the helical portion corresponds to helical portions 189 and 289.

[0373] In an alternative embodiment, for the drive tube in the first position, the axial portions of the housing assembly and the guide structure of the drive tube are abutted, and the helical portions of the housing assembly and the guide structure of the drive tube are abutted, wherein, for the drive tube in the second position, an axial clearance is provided between the axial portions of the housing assembly and the drive tube, whereby the helical portion of the drive tube can slide onto the helical portion of the housing assembly. The axial portions of the housing assembly and the guide structure of the drive tube correspond to axial portions 156, 256, 182, and 282 of the housing assembly and the guide structure of the drive tube. The helical portions of the housing assembly and the guide structure of the drive tube correspond to helical portions 157, 257, 189, and 289 of the housing assembly and the guide structure of the drive tube in the first and second embodiments.

[0374] In an alternative embodiment, each delivered dose has an equal volume.

[0375] In an alternative embodiment, the drug delivery device includes an activation mechanism, whereby each delivered dose has an equal volume.

[0376] In an alternative embodiment, the drive spring is pre-tensioned with a constant force to deliver a predetermined plurality of doses, wherein the force can be measured as an axial force transmitted from the piston rod, and wherein the constant force is defined as a force that varies by less than 20 percent between the first and last doses. During the administration of a predetermined plurality of fixed doses, this force can be measured by placing a force sensor between the piston rod and piston of the cartridge.

[0377] In an alternative embodiment, the predetermined plurality of fixed doses is 2, 3, 4, 5 or 6, preferably 4.

[0378] In an alternative embodiment, the drug delivery device includes a drug filling cartridge with a piston arranged proximally, wherein the piston rod (109, 209) is operatively arranged to advance the piston. The cartridge corresponds to cartridges 135, 235 in the first and second embodiments, and the piston corresponds to pistons 136, 236.

[0379] In an alternative embodiment, the drug delivery device includes an integrated needle sheath, and the activation mechanism includes an axially movable needle shield for covering and exposing the needle. The shield is adapted to activate the drive mechanism in response to movement in the proximal direction, thereby exposing the needle. The needle sheath corresponds to needle sheaths 124, 224 in the first and second embodiments, and the shield corresponds to elongated shield structures 110, 210.

[0380] In an alternative embodiment, the drug delivery device includes a needle hub for releasably mounting an injection needle, and wherein the activation mechanism includes an axially movable release button adapted to activate the drive mechanism in response to axial movement. The release button corresponds to the shield of the first and second embodiments.

[0381] In an alternative embodiment, the activation mechanism includes a connector operatively connected to the drive mechanism, wherein the connector is adapted to activate the drive tube in response to axial movement. The connector corresponds to connectors 170 and 270 in the first and second embodiments.

[0382] In an alternative embodiment, the activation mechanism includes a shield for covering the integrated needle tip and a connector operatively connected to the drive mechanism, wherein the shield is operatively arranged to engage the connector in response to rotation of the shield, and wherein the shield is axially movable and adapted to move the connector, and thus adapted to activate the drive tube in response to axial movement. The needle sheath corresponds to needle sheaths 124, 224 in the first and second embodiments, and the shield corresponds to elongated shield structures 110, 210. The connector corresponds to connectors 170, 270 in the first and second embodiments.

[0383] In an alternative embodiment, the first position of the drive tube is a distal position and the second position is a proximal position.

[0384] In an alternative embodiment, the drug delivery device is an injection device.

[0385] In an alternative embodiment, the drug delivery device further includes a drug reservoir with a piston arranged to discharge drug from the reservoir, wherein a piston rod is adapted to axially advance the piston, and wherein the piston rod is splined axially connected to the housing assembly, thereby allowing the piston rod to be axially movable and rotationally locked relative to the housing assembly. The drive tube also includes internal threads, and the piston rod further includes external threads for threaded engagement of the internal threads of the drive tube, thereby operably connecting the piston rod to the housing assembly and the drive tube, and allowing it to be advanced during rotation of the drive tube. The drive mechanism further includes a compression drive spring for axially moving the drive tube and the piston, thereby adapting the drive mechanism and the drive guide portion to drive the drive tube to the first position. During activation, the drive tube moves together with the piston rod, thereby separating the piston rod from the piston. During dosing, the drive tube performs a combination of axial and rotational movements, with contributions from the axial movement of the drive tube and from the rotational movement causing the piston rod to move axially.

[0386] In an alternative embodiment, the drug delivery device further includes an axially movable spring base, wherein the compression drive spring is located between the spring base and the housing, thereby connecting the torque drive spring and the compression drive spring in series. The spring base corresponds to spring bases 165 and 265 in the first and second embodiments.

[0387] In an alternative embodiment, the compression drive spring is integrated with the torsion drive springs 108 and 208 corresponding to the first and second embodiments, wherein the drive spring is a torsion drive spring having a compression section.

[0388] In an alternative embodiment, a drug delivery device is provided for sequentially delivering a predetermined plurality of fixed doses, wherein the drug delivery device includes a housing assembly, a drive mechanism, and an activation mechanism.

[0389] The housing assembly includes a guide structure, which includes a stop and activate guide portion and a drive guide portion. The drive guide portion corresponds to the spiral portions 157 and 257 of the first and second embodiments, and the stop and activate guide portion corresponds to the axial portions 156 and 256 of the first and second embodiments.

[0390] The drive mechanism is adapted to sequentially deliver a predetermined plurality of doses and includes a drive tube, a torsion drive spring, and a piston rod. The drive tube is adapted to be guided along the stop and activate guide portion to activate the drive mechanism. The drive tube is also adapted to be guided along the drive guide portion to deliver a fixed dose and to be guided to the stop and activate guide portion, wherein dosing is stopped by stopping rotation of the drive tube. Therefore, the drive tube is adapted to be guided in response to a drive tube dosing sequence including activation, dosing, and stopping dosing. The torsion drive spring is adapted to conserve an initial amount of energy and to rotate the drive tube, i.e., in the out-of-package state, the torsion spring is pre-tensioned by coiling, thereby conserving an initial amount of energy. The piston rod is operatively connected to the housing assembly and the drive tube. The drive tube, torsion drive spring, and piston rod correspond to drive tubes 180, 280, torsion drive springs 108, 208, and piston rods 109, 209.

[0391] The activation mechanism is adapted to move the drive tube along the stop and activation guide portion from a first axial position to a second axial position in a first axial direction, thereby activating the drive mechanism. In some embodiments, the drug delivery device may include a cover or button adapted to operate the activation mechanism to activate the drive mechanism.

[0392] The drive mechanism is further adapted to bias the drive tube in a second axial direction opposite to the first axial direction. The drive mechanism is adapted to rotate the drive tube along the drive guide portion to the stop and activate guide portion in response to activation of the drive mechanism, thereby delivering a fixed dose of a predetermined plurality of fixed doses, wherein the drive tube is operatively positioned to be guided along the stop and activate guide portion to deliver a subsequent fixed dose of the plurality of fixed doses. In some embodiments, the biasing device may be a compressible torsion drive spring, or a compressible return spring connected in series with the torsion drive spring.

[0393] Each activation of the drive mechanism and the completion of the drive tube dose sequence reduces the amount of energy stored in the torsion drive spring. The initial amount of stored energy, which is the energy stored before the first activation, is sufficient or greater than the energy required to deliver a predetermined number of fixed doses.

[0394] In the above description of exemplary embodiments, different structures and devices for providing the functions of different components have been described to the extent that those skilled in the art will understand the concept of the invention. The detailed construction and description of the different components are considered to be part of the normal design process performed by those skilled in the art following the routes set forth in this specification.

Claims

1. A drug delivery device for sequentially delivering a predetermined plurality of fixed doses, wherein the drug delivery device comprises: - Housing components, - A drive mechanism including drive tubes (180, 280), wherein the drive mechanism is adapted to sequentially deliver the predetermined plurality of fixed doses, and, - An activation mechanism for activating the drive mechanism. The drive mechanism includes a pre-tensioned torsion drive spring (108, 208) that stores an initial amount of energy and is adapted to rotate the drive tube (180, 280). Each activation of the drive mechanism and completion of the drive tube dose sequence reduces the amount of energy stored in the drive spring (108, 208), and the initial amount of stored energy, which is the energy stored before the first activation, is sufficient to deliver the predetermined plurality of fixed doses.

2. The drug delivery device according to claim 1, wherein... - The housing assembly includes a guide structure, which includes a stop and activate guide portion (156, 256) and a drive guide portion (157, 257); - The drive tube (180, 280) is adapted to be guided along the stop and activate guide portions (156, 256) to activate the drive mechanism, and along the drive guide portions (157, 257) to deliver a fixed dose, and guided to the stop and activate guide portions, wherein dosing is stopped, thereby the drive tube is adapted to be guided in response to the execution of a drive tube dosing sequence including activation, dosing, and stopping dosing; - The drive mechanism further includes a piston rod operably connected to the housing assembly and the drive tube; - The activation mechanism is adapted to move the drive tube from a first axial position to a second axial position along the stop and activation guide portions (156, 256) in a first axial direction, thereby activating the drive mechanism.

3. The drug delivery device of claim 2, wherein the drive mechanism is further adapted to bias the drive tube in a second axial direction opposite to the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube (180, 280) along the drive guide portion (157, 257) to the stop and activate guide portion (156, 157) in response to activation of the drive mechanism, thereby delivering a fixed dose of the predetermined plurality of fixed doses, and wherein the drive tube is operatively positioned to be guided along the stop and activate guide portion to deliver a subsequent fixed dose of the plurality of fixed doses.

4. The drug delivery device according to any one of claims 2-3, wherein the housing assembly further includes internal threads, wherein the piston rod (109, 209) further includes external threads for threaded engagement of the internal threads of the housing assembly, wherein the drive tube (180, 280) is axially connected to the piston rod by a spline, thereby allowing the drive tube to be axially movable and rotatably locked relative to the drive tube, thereby allowing the piston rod to be operatively connected to the housing assembly and the drive tube.

5. The drug delivery device according to claim 3, wherein the torsion drive springs (108, 208) are compressed, thereby adapting the drive mechanism to bias the drive tubes (180, 280) in the second axial direction.

6. The drug delivery device according to any one of claims 1 to 3, wherein the torsion drive spring (108, 208) is arranged between the drive tube (180, 280) and the housing assembly.

7. The drug delivery device according to any one of claims 1 to 3, wherein the housing assembly includes a fixed spring base (165, 265), wherein one end of the torsion drive spring (108, 208) is attached to the fixed spring base.

8. The drug delivery device according to claim 2 or 3, wherein the stop and activate guide portions (156, 256) of the guide structure are axial portions, and wherein the drive guide portions (157, 257) of the guide structure of the housing assembly include helical portions.

9. The drug delivery device according to claim 2 or 3, wherein the drive tube (180, 280) includes corresponding guide structures (182, 189, 282, 287) adapted to cooperate with the guide structures (156, 157, 256, 257) of the housing assembly.

10. The drug delivery device according to claim 9, wherein the guiding structure (182, 189, 282, 287) of the drive tube includes an axial portion (182, 282) and a helical portion (189, 289).

11. The drug delivery device of claim 10, wherein for the drive tube (180, 280) in the first position, the housing assembly and the axial portions (156, 256, 182, 282) of the guide structure of the drive tube are abutted, and the helical portions (157, 257, 189, 289) of the guide structure of the drive tube are abutted, and wherein, For the drive tube in the second position, an axial clearance is provided between the housing assembly and the axial portions (156, 256, 182, 282) of the drive tube, whereby the helical portions (189, 289) of the drive tube can slide onto the helical portions (157, 257) of the housing assembly.

12. The drug delivery device of claim 2 or 3, wherein the drive spring is pre-tensioned with a constant force to deliver the predetermined plurality of fixed doses, wherein the force can be measured as an axial force transmitted from the piston rod, and wherein the constant force is defined as a force that varies by less than 20 percent between the first dose and the last dose.

13. The drug delivery device according to claim 2 or 3, wherein the drug delivery device comprises a drug filling cylinder (135, 235) having a piston (136, 236) arranged proximally, wherein the piston rod (109, 209) is operatively arranged to advance the piston.

14. The drug delivery device according to any one of claims 1 to 3, wherein the drug delivery device includes an integrated needle (124, 224), and wherein the activation mechanism includes an axially movable needle shield (110, 210) for covering and exposing the needle, wherein the shield is adapted to activate the drive mechanism in response to movement in the proximal direction, thereby exposing the needle.

15. The drug delivery device according to any one of claims 1 to 3, wherein the drug delivery device includes a needle hub for an injection needle, and wherein the activation mechanism includes an axially movable release button adapted to activate the drive mechanism in response to axial movement.

Images