Drive mechanism for an injection device

Abstract

To provide an injection device for discharging several previously set or user-selectable doses of medicines.SOLUTION: An opposing party member and a rotatable member of an injection device include a dose setting mechanism including a first mechanical code 242 and a second mechanical code each, the rotatable member can be rotated within a range of a number of rotation states relative to a housing and the opposing party member for setting a dose, the rotatable member is restrained along a longitudinal axis relative to the housing or the opposing party member during setting of a dose, and one of the rotatable member and the one's opposing party member can be displaced to a discharge position along a longitudinal axis relative to the other of the rotatable member and the opposing party member only when the first mechanical code is aligned to the second mechanical code for discharging a dose.SELECTED DRAWING: Figure 25

Description

[Technical field]

[0001] The present disclosure relates in one embodiment to an injection device, such as a pen-type injector, for the ejection of a preset or user-selectable dose of a medicament. In particular, the present disclosure relates to an injection device including an ejection mechanism, such as a wind-up ejection mechanism, and including a dose setting mechanism, the dose setting mechanism being configured to prevent or block the dose ejection procedure when the actual set dose does not match the predetermined or prescribed dose size. [Background technology]

[0002] As such, injection devices for setting up and dispensing single or multiple doses of liquid medicaments are well known in the art. In general, such devices have a purpose substantially similar to that of a conventional syringe.

[0003] Injection devices, especially pen-type injectors, must meet several user-specific requirements. For example, in the case of patients with chronic diseases such as diabetes, the patients may be physically frail and may also have visual impairments. Therefore, a suitable injection device, especially intended for home medicines, must be robust in construction and easy to use. Furthermore, the operation and general handling of the device and its components must be clear and easily understandable. Furthermore, the dose setting and dose dispensing procedures must be easy to operate and clear.

[0004] Typically, such devices include a housing including a specific cartridge holder adapted to receive a cartridge at least partially filled with the medicament to be dispensed. Such devices further include a drive or ejection mechanism, usually having a displaceable piston rod adapted to operatively engage with the piston of the cartridge. By means of the drive mechanism and its piston rod, the piston of the cartridge can be displaced in a distal or dispensing direction, thus ejecting a predetermined amount of medicament through a piercing assembly that is to be releasably coupled with the distal end of the housing of the injection device.

[0005] The medicament to be dispensed by the injection device is provided and contained in a multi-dose cartridge. Such cartridges typically include a glass barrel that is sealed distally with a pierceable closure and further sealed proximally by a piston. In the case of a reusable injection device, the empty cartridge can be replaced with a new one. In contrast, a disposable type injection device is to be discarded when the medicament in the cartridge has been dispensed or used up.

[0006] In some applications, it may be advantageous to limit the minimum drug dose that can be administered from the device as well as the maximum dose. This can ensure, for example, that only therapeutically effective amounts are administered. Such functionality is particularly relevant for drug combinations, where a minimum amount of combined drugs is required to ensure sufficient delivery of one component of the combination to be therapeutically effective, while allowing some variation in dose that is important for other components of the combination.

[0007] In some applications, it may be advantageous to provide a device that allows for the delivery of only one fixed dose value or multiple dose values. It may be desirable to provide a minimum fixed dose value and a device that allows for the delivery of integer multiples of the minimum fixed dose value.

[0008] A further application is for treatments where different discrete, non-contiguous doses of a pharmaceutical are required. For example, different doses may be required to meet the therapeutic needs of different user groups, or to allow individual users to deliver different doses at different times of the day, e.g., in the morning or in the evening.

[0009] It is therefore desirable to have an injection device that provides a restriction of the deliverable dose value to a limited number of commonly available dose values. The injection device should allow the delivery of only one or a few fixed dose values. The injection device should be configured to prevent setting or expelling a dose that does not match a pre-describe or predetermined dose size. Summary of the Invention [Means for solving the problem]

[0010] In one embodiment, an injection device is provided for ejection of a number of preset or user-selectable doses of a medicament, typically a liquid medicament. The injection device includes an elongated housing extending along a longitudinal axis or along a main axis. The housing is configured to accommodate a cartridge, the cartridge containing the medicament and having a bung sealing the proximal end of the cartridge. The injection device further includes an ejection mechanism including a trigger and a piston rod. When triggered by the trigger, the piston rod is configured to urge against the bung along the longitudinal axis in a distal direction relative to the housing. The drive mechanism is configured to apply a drive force or drive impulse to the piston rod by depressing the trigger in a distal direction to urge the piston rod against the bung to eject the medicament from the distal end of the cartridge.

[0011] The injection device further includes a dose setting mechanism. The dose setting mechanism includes a rotatable member and a mating member. The mating member includes a first mechanical code. The rotatable member includes a second mechanical code. The first and second mechanical codes are of complementary shape. The first mechanical code corresponds to a code of the second mechanical code and vice versa.

[0012] For setting the dose, the rotatable element is rotatable relative to the housing and relative to the counter member within a number of rotational states. During setting the dose, the rotatable member is constrained along the longitudinal axis relative to the housing or relative to the counter member. In other words, at least during setting the dose, the rotatable member is exclusively subjected to rotational movement relative to the housing and / or relative to the counter member. At least during setting the dose, the rotatable member is axially constrained or axially fixed to the housing and / or the counter member.

[0013] For ejection of a dose, one of the rotatable member and the counter member is displaceable along the longitudinal axis relative to the other of the rotatable member and the counter member to an ejected position only when the first mechanical code is aligned with the second mechanical code. If the first mechanical code is not aligned with the second mechanical code, longitudinal displacement of the rotatable member and the counter member relative to one another to reach the ejected position is effectively blocked or prevented by mismatch of the mechanical codes of the rotatable member and the counter member.

[0014] The corresponding and complementary shaped first and second mechanical cords of the rotatable member and mating member limit longitudinal or axial displacement of the rotatable member relative to the mating member to such a configuration of the rotatable member in which the first mechanical cord is aligned with the second mechanical cord.

[0015] Typically, the ejection mechanism and the dose setting mechanism are switchable between a dose ejection mode and a dose setting mode. In the dose setting mode, the piston rod is stationary while the user is provided with the possibility to set a dose of a desired size. The dose setting may involve the rotation of the rotatable member. Typically, the rotatable member is rotatable relative to the counter member and relative to the housing within a number of discrete rotational states. Each discrete rotational state may correspond to a standard unit of a dose of the drug. During the dose setting, when the rotatable member is rotated from one discrete rotational state to a successive discrete rotational state, the dose size may increase by a standard unit of the drug or by a multiple of the standard unit.

[0016] The first and second mechanical codes are configured and selected such that only some predetermined rotational states of the rotatable member out of a range of many rotational states allow the first mechanical code to align with the second mechanical code and thus allow relative axial or longitudinal displacement of the rotatable member with respect to the other member. In this manner, the number of different size dose values ​​that can be set and dispensed by the injection device can be reduced to a desired minimum value. Typically, the first and second mechanical codes are configured to allow for setting and dispensing at least one predetermined size dose. The first and second mechanical codes may further be configured to allow and support setting and dispensing a second predetermined dose and / or a third predetermined dose. The second predetermined dose may be twice as large as the first predetermined dose. In particular, the first and second mechanical codes may be configured to allow and support setting and dispensing one predetermined dose size and further dose sizes that are integer multiples of the predetermined dose size.

[0017] It is particularly useful that the rotatable member and / or the counter member are integrated into existing components of the injection device. The implementation of the first mechanical code into the counter member and the integration of the second mechanical code into the rotatable member only require a redesign or reconstruction of at least one of the counter member and the rotatable member, which are anyway present in the injection device. To this extent, the functionality of the injection device as described herein can generally be obtained without the implementation of additional mechanical components in the dose setting mechanism or the ejection mechanism.

[0018] The ejection mechanism may include a wind-up ejection mechanism. Such a wind-up ejection mechanism includes, among other things, a mechanical energy store. The mechanical energy store is pre-installed or pre-energized when the injection device is manufactured. Optionally, the mechanical energy store can be further energized or tensioned when the dose is actually dialed or set through the dose setting mechanism. In this manner, the mechanical energy stored in the mechanical energy store can be increased during dose setting.

[0019] Typically, and during dose setting, a mechanical energy store is coupled to the piston rod for transmitting a driving force or torque to the piston rod to drive and displace the piston rod distally. The release of energy from the mechanical energy store to the piston rod can be controlled and / or triggered by a trigger. By means of one or several clutches, the mechanical energy of the energy store can be transferred to a driving impulse or force acting on the piston rod to drive the piston rod distally relative to the housing. The trigger can be operatively coupled to one or several clutches of the wind-up ejection mechanism and / or the dose setting mechanism to release the distal movement of the piston rod under the effect of the depleting mechanical energy store.

[0020] The first mechanical cord is complementary in shape to the second mechanical cord and vice versa. The first mechanical cord can be axially offset from the second mechanical cord while the other is in the dose setting position. The first mechanical cord can be located axially or longitudinally away from the second mechanical cord as long as the dose setting mechanism and / or the ejection mechanism are in the dose setting mode.

[0021] The injection device can be switched to the dose ejection mode by displacing at least one of the rotatable member and the counter member to the ejection position. When at least one of the rotatable member and the counter member is in or reaches the ejection position, the injection device is switched to the dose ejection mode. When in the dose ejection mode, the piston rod is subjected to a distal forward movement, thus urging against the bung. Switching from the dose setting mode to the dose ejection mode is typically triggered by depressing the trigger, typically in a distal direction, relative to the housing. The distal displacement of the trigger is transmitted either directly or via at least one additional member, for example by a clutch to one of the rotatable member and the counter member, thus inducing a respective longitudinal displacement of the counter member relative to the rotatable member.

[0022] To switch the injection device into the dose ejection mode, at least one of the rotatable member and the counter member is typically subjected to a longitudinal or axial sliding displacement relative to the housing of the injection device. For example, one of the rotatable member and the counter member is subjected to a distal sliding displacement relative to the housing, while the other of the rotatable member and the counter member is axially fixed relative to the housing. To switch the injection device from the dose setting mode to the dose ejection mode, one of the rotatable member and the counter member is axially displaceable, for example slidably axially displaceable, relative to the other of the rotatable member and the counter member.

[0023] When the first mechanical code and the second mechanical code are not aligned, axial or longitudinal displacement of the rotatable member relative to the mating member is blocked by the first and second mechanical code, thus preventing and inhibiting switching of the injection device to the dose ejection mode.

[0024] The mechanical blocking induced by the misaligned first and second mechanical cords may even be transmitted back to the trigger, which cannot be fully depressed in the distal direction unless the first and second mechanical cords are aligned. In this manner, immediate feedback is provided to the user. The dose ejection operation of the injection device cannot be initiated or triggered unless the first and second mechanical cords are aligned, and therefore unless the actual dose set corresponds to the predetermined dose size. Finally, the trigger of the ejection mechanism cannot be fully depressed in the distal direction.

[0025] For switching the injection device from a dose setting mode to a dose ejection mode, at least one of the rotatable member and the counter member is displaceable relative to the other of the rotatable member and the counter member. For example, in one example, the rotatable member is axially constrained along the longitudinal axis relative to the housing only when the injection device is in the dose setting mode. For switching the injection device to a dose dispensing mode, the rotatable member is axially displaceable relative to the housing and relative to the counter member. Here, the counter member is rigidly attached to the housing. In another example, during switching of the device from a dose setting mode to a dose ejection mode, it is the counter member that is exclusively subjected to longitudinal displacement. Here, the rotatable member is axially fixed to the housing during dose setting as well as during dose ejection. In a further example, for switching of the injection device from a dose setting mode to a dose ejection mode, it is even conceivable that both the rotatable member and the counter member are subjected to longitudinal displacement relative to the housing and relative to each other.

[0026] According to a further example, longitudinal displacement of one of the rotatable member and the mating member to the ejection position is prevented unless the first and second mechanical cords are aligned. Only when the first and second mechanical cords are aligned with each other do they permit and enable their relative longitudinal displacement. When properly aligned, the first mechanical cord can receive at least a portion of the second mechanical cord and vice versa. When properly aligned, the first and second mechanical cords can be arranged in an at least partially interleaved or overlapping configuration.

[0027] In one example, the second mechanical cord can pass through the first mechanical cord, or vice versa. Thus, when reaching the ejection position, the first mechanical cord and the second mechanical cord are either mechanically engaged with each other, e.g., locked against rotation, or one of the first and second mechanical cords passes through the other of the first and second mechanical cords. In the latter case, the first and second mechanical cords are mechanically disengaged when reaching the ejection position. In one example of the dose setting position, the second mechanical cord is located distally from the first mechanical cord. When correctly aligned, the second mechanical cord can pass through the first mechanical cord, and thus reaches the distal side of the first mechanical cord when reaching the ejection position of at least one of the rotatable member and the counter member.

[0028] When properly aligned, the first and second mechanical codes enable longitudinal displacement of at least one of the rotatable member and the mating member toward and to the ejection position over a mode-switching distance. The mode-switching distance is greater than the distance by which at least one of the rotatable member and the mating member can be longitudinally moved relative to the other of the rotatable member and the mating member when the first and second mechanical codes are not aligned. When the first mechanical code is properly aligned with the second mechanical code, the distance by which at least one of the rotatable member and the mating member can be longitudinally displaced toward the ejection position is a maximum. This maximum distance is greater than or equal to the mode-switching distance required to switch the injection device from a dose setting mode to a dose ejection mode.

[0029] In another example, the injection device further includes a dosing spring that is compressible along the longitudinal direction. The dosing spring is further engaged with one of the rotatable member and the mating member. The dosing spring is directly or indirectly engaged with one of the rotatable member and the mating member. The rotatable member or the mating member is displaceable along the longitudinal direction from a dose setting position to a dose ejection position against the action of the dosing spring. Thus, the dosing spring is configured to return the rotatable member or the mating member from the dose ejection position towards and to the dose setting position.

[0030] In other words, in the initial configuration and when the user grasps the injection device for setting a dose, the rotatable member or the counter member is located in a dose setting position. It is permanently maintained or biased in the dose setting position by the dosing spring. It is then displaceable to a dose ejection position against the action of the dosing spring, assuming that the first and second mechanical codes are correctly aligned. Typically, one of the rotatable member and the counter member that is longitudinally displaceable under the action of the dosing spring is also mechanically engageable with the trigger.

[0031] Typically, the trigger is also longitudinally displaceable from a dose set position to a dose ejection position against the action of the dosing spring. Both the trigger and the rotatable or mating member are displaceable from a dose ejection position to an initial dose set position under the action of the dosing spring. The spring may include a longitudinally extending compression spring configured to induce a longitudinal displacement of at least one of the rotatable member, the mating member, and the trigger toward an initial dose setting position. Typically, the dose setting position is a proximal position, and the dose ejection position is a distal position. When the rotatable member, the mating member, or the trigger is displaced from the dose setting position to the dose ejection position, it is subjected to a distal displacement. For example, when the trigger is released, at least one of the rotatable member, the mating member, and the trigger is displaced in the opposite direction, i.e., in the proximal direction, to the dose setting position.

[0032] In a further example, at least one of the rotatable member and the trigger is maintained in a proximal dose setting position under the action of a dosing spring. In this manner, dialing or setting of the dose, which involves rotation of the rotatable member relative to the housing and relative to the counter member, respectively, can be triggered immediately by the user, i.e., without any further manipulation of at least one of the rotatable member, the counter member, or the trigger.

[0033] According to a further example, the first mechanical cord and the second mechanical cord each include at least a first cord feature. The first cord feature includes at least one of a protrusion and a recess. Typically, the first mechanical cord includes one or more of such cord features, and the second mechanical cord includes one or more of such cord features. The cord feature of the first mechanical cord is of a complementary shape to the cord feature of the second mechanical cord. For example, when the first mechanical cord includes a first cord feature having a protrusion, the second mechanical cord includes a first cord feature having a recess that matches the protrusion of the first mechanical cord. The cord feature can further include not only a single protrusion and a single recess, but also a sequence or pattern of at least one protrusion and at least one recess. The second mechanical cord that matches the first mechanical cord includes a corresponding sequence or pattern of protrusions and recesses.

[0034] When in the dose setting position, at least one protrusion or recess of the first mechanical cord is aligned with, but does not engage, a correspondingly shaped recess or protrusion of the second mechanical cord.

[0035] When at least one of the rotatable member and the mating member is subjected to a longitudinal displacement toward the ejection position, at least one protrusion or recess of the first mechanical cord engages with, slides into, or slides through at least one recess or protrusion of the second mechanical cord.

[0036] Typically, at least one protrusion of the first cord feature of one of the first and second mechanical cords includes an abutment surface, which allows the protrusion to abut axially or longitudinally with an abutment surface of the other of the first and second mechanical cords. In this manner, and for example when the protrusion of the first mechanical cord is not aligned with the recess of the second mechanical cord, the protrusion abuts the second mechanical cord when at least one of the rotatable member and the counter member is moved towards the ejection position. As soon as the abutment surface of the protrusion of one of the first and second mechanical cords abuts the other of the first and second mechanical cords, further axial or longitudinal displacement of the rotatable member relative to the counter member is blocked and prevented.

[0037] According to a further example, the first mechanical cord and the second mechanical cord each include at least a second cord feature including at least one of a protrusion and a recess. In other words, each of the first mechanical cord and the second mechanical cord includes the first cord feature and at least a second cord feature, and optionally a third cord feature, a fourth cord feature, or even further code features. Each of the code features of the first mechanical cord and the second mechanical cord includes at least one of a protrusion and a recess. A code feature may include only one protrusion, or only one recess. One of the first and second code features may also include both a protrusion and a recess, or even a sequence of protrusions and recesses. Typically, and according to another example, the first and second code features are arranged at a predetermined angular distance from each other on the circumference of at least one of the counter member and the rotatable member.

[0038] By having multiple cord features, the first and second mechanical cords can be distributed and spread out along the circumference of at least one of the mating member and the rotatable member. In this manner, increased abutment between the rotatable member and the mating member can be achieved, reducing blocking forces that would be transmitted between the first and second mechanical cords in the event of misalignment.

[0039] The maximum blocking force that would be provided by the first and second mechanical cords in the case of the misaligned configuration can be effectively distributed over multiple cord features of the first and second mechanical cords. More than just one cord feature is even more useful when the rotatable member and the counter member are non-rotatably lockable or non-rotatably engageable when reaching the ejection position. The torque or force transmitted from the rotatable member to the counter member can then be divided between multiple cord features of the first and second mechanical cords.

[0040] The first and second code features can be arranged at a predetermined angular distance from each other on the inner or outer circumference of at least one of the counter member and the rotatable member. For example, when the counter member is insertable into a hollow-shaped rotatable member, the code feature of the counter member is typically provided on the outer circumference of the counter member and the code feature of the rotatable member is provided on the inner circumference or inner circumference of the rotatable member. The code feature of the counter member can be located on the outer wall of the sleeve-shaped counter member. The code feature of the rotatable member can be provided on the inner wall of a receptacle or hollow part of the rotatable member. In another example, it may be a rotatable member that is received inside a hollow part or hollow receptacle of the counter member. The code feature of the counter member is then provided on the inner circumference of the counter member, hence on the inward-facing side wall of the counter member, and the code feature of the rotatable member is provided on the outer surface, hence on the outer circumference of the rotatable member.

[0041] The first mechanical cord can be provided on a longitudinal end of the counter member facing the rotatable member, and the second mechanical cord can be provided on a longitudinal end of the rotatable member facing the counter member.

[0042] When the rotatable member is implemented, for example, as a trigger, the first mechanical code can be provided at its distal end, while the counter member can be provided or integrated in a proximal part of the housing, for example at the proximal end of the housing.

[0043] According to another example, at least one of the first mechanical cord and the second mechanical cord includes at least two or more cord features that are equidistantly or equiangularly arranged around the circumference of at least one of the mating member and the rotatable member. The equidistant or equiangular arrangement of two or more cord features around the circumference, e.g., the inner or outer circumference, of at least one of the mating member and the rotatable member has the advantage that the mating member and the rotatable member can engage via the first mechanical cord and the second mechanical cord when properly aligned.

[0044] By increasing the number of interengaging cord features of the mating member and the rotatable member, the total force and stability of the mechanical engagement provided by the first and second mechanical cords can be improved. Thus, a somewhat more robust and stable mechanical engagement between the first and second mechanical cords can be provided. This is advantageous, for example, when the rotatable member and the mating member are non-rotatably locked in the ejected position, where the rotational interlock between the first and second mechanical cords is configured to transfer angular momentum across the interface of the rotatable member and the mating member when in the ejected position.

[0045] With equidistant and equally shaped cord features, the number of allowable alignment configurations of the first and second mechanical cords per revolution of the rotatable member relative to the mating member increases accordingly. With two cord features, there are two of the rotational states of the rotatable member in which the first and second mechanical cords are longitudinally aligned. With three identically shaped and equidistantly or equiangularly aligned cord features, there are three rotational states of the rotatable member in which the first and second mechanical cords are properly aligned, and so on.

[0046] The two or more code features of one of the first and second mechanical cords are of equal or different shapes. With two identically shaped and equidistantly or equiangularly aligned code features of the first and second mechanical cords, there are two rotational states of the rotatable member per revolution in which the first and second mechanical cords are aligned. With three identically shaped and equidistantly or equiangularly aligned code features of the first and second mechanical cords, there are three alignment configurations of the first and second mechanical cords per revolution of the rotatable member from which the injection device can be switched to a dose ejection mode. With differently shaped first and second code features or with non-equidistant or non-equidistant angular separation of the code features, there is only one allowable alignment configuration of the first and second mechanical cords per revolution of the rotatable member.

[0047] According to a further example, the at least one protrusion is a radial protrusion and the at least one recess is a radial recess. For a protrusion extending radially inward, the recess also extends radially inward. For a protrusion extending radially outward, a radial recess of complementary shape also extends radially outward. The radial protrusion includes a cross-section that matches the cross-section of the radial recess. When the first mechanical cord is correctly aligned with the second mechanical cord, the radial protrusion can slide into the radial recess of complementary shape when at least one of the rotatable member and the counter member is subjected to a longitudinal displacement towards the ejection position.

[0048] When in the ejected position, the radial projection may still be located inside the radial recess or may pass longitudinally through the radial recess. When the radial projection remains engaged with the radial recess upon reaching the ejected position, the rotatable member and the counter member are non-rotatably engaged or non-rotatably locked. Thus, any further rotation of the rotatable member or the counter member is transmitted equally and therefore unchanged to the other of the rotatable member and the counter member.

[0049] In another example, the radial protrusion can be located on a first side of the radial recess, longitudinally away from the radial recess. When at least one of the rotatable member and the counter member is moved to the ejection position, the radial protrusion can pass through the radial recess and then be located on the opposite side, and therefore on the second side, of the radial recess. In this example, the rotatable member and the counter member can rotate freely relative to each other even when the ejection position is reached and when the injection device is switched to the dose ejection mode.

[0050] According to a further example, the radial projection comprises an elongated rib extending along the longitudinal direction and / or the radial recess comprises an elongated groove extending along the longitudinal direction. In other words, the radial projection and the elongated rib are configured to form a splined engagement of the rotatable member and the counter member. For this, one of the projection and the recess only needs to be elongated along the longitudinal direction. With the elongated rib and / or the elongated groove, a torque-resistant engagement between the first and second mechanical cords and between the rotatable member and the counter member can be established and obtained as soon as the rib or projection enters the recess or the elongated groove. With the elongated rib and / or the elongated groove, the rotatable member of the counter member is subjected to a relative longitudinal displacement while the rotational connection between them is maintained.

[0051] According to another example, the at least one protrusion is an axial protrusion extending along the longitudinal direction. The at least one recess is of corresponding shape and comprises an axial recess extending along the longitudinal direction. The first and second mechanical cords may be provided with a multiplicity of axial protrusions and axial recesses. Here, the first and second mechanical cords may be provided on end faces or on distally or proximally facing flanges of the rotatable member and / or the counter member, respectively.

[0052] For example, the axial protrusions and / or axial recesses of the cord features of at least one of the first and second mechanical cords can be provided on end faces of at least one of the rotatable member and the mating member, the end faces facing longitudinally, e.g., in the proximal or distal direction. Such axially extending and interengaging cord features are particularly useful for implementation with rotatable members or mating members having relatively thin side walls. In the case of a radial recess, the thickness of the side wall should be at least somewhat greater than the radial depth of the radial recess.

[0053] In another example, at least one of the axial protrusions and the axial recesses includes a tapered or toothed structure oriented in the longitudinal direction. Typically, the first mechanical cord includes both at least one axial protrusion and at least one axial recess. The second mechanical cord also includes at least one of both an axial protrusion and an axial recess that are complementary in shape to the axial protrusions and axial recesses of the first mechanical cord. The tapered or toothed structure of at least one of the axial protrusions and axial recesses further provides limited circumferential guidance functionality as the first mechanical cord approaches the second mechanical cord in the longitudinal direction. If the first mechanical cord is not to be absolutely precisely angularly aligned with the second mechanical cord, the tapered or toothed structure of the mutually corresponding axial protrusions and axial recesses can provide and induce an additional somewhat smaller rotation of at least one of the rotatable member and the mating member when one of the rotatable member and the mating member is longitudinally displaced toward the ejection position.

[0054] The longitudinally oriented tapered or toothed structure of the first and second mechanical cords also provides a torque-resistant engagement between the rotatable member and the mating member. If the axial projection is sized to completely fill the axial recess, the rotatable member can be effectively locked to the mating member when the ejection position is reached. Also here, at least one axial projection and at least one axial recess of the first and second mechanical cords can non-rotatably lock the respective mechanical cords, and thus the rotatable member and the mating member. This is particularly useful to prevent rotation of the rotatable member during the dose ejection procedure.

[0055] For example, at least one of an axial protrusion and an axial recess can be provided on a trigger configured as a rotatable member, The other can be provided on the housing of the injection device. When the rotatable member, and thus the trigger, is depressed in a distal direction and thus reaches the ejection position, the trigger can be locked against rotation relative to the housing through mutually corresponding and interengaging protrusions and recesses.

[0056] According to a further example, at least one of the first mechanical cord and the second mechanical cord can include a crown wheel or a crown gear. The crown wheel or crown gear can be broken to represent one of the first or second mechanical cords. For example, the crown gear of one of the rotatable member and the mating member can be broken and include a somewhat flat-shaped abutment surface, thus representing a section of the crown gear that is an axial recessed void. When improperly aligned or when the first and second mechanical cords are not aligned, the axially protruding teeth of one of the rotatable member and the mating member face the abutment or abutment surface of the other of the rotatable member and the mating member, thus preventing longitudinal displacement of at least one of the rotatable member and the mating member relative to the other of the rotatable member and the mating member. The teeth cannot engage and cannot prevent further longitudinal displacement of the rotatable member or the mating member toward the ejection position.

[0057] According to another example, the counter member and the rotatable member are non-rotatably connectable or non-rotatably lockable to each other through the first and second mechanical cords. This can be achieved either by radial projections and radial recesses provided on the rotatable member and the counter member, or alternatively by at least one axial projection and at least one axial recess on the rotatable member and on the counter member. In any case, the rotatable member and the counter member can be non-rotatably engaged when the first and second mechanical cords are mutually aligned and when the rotatable member and the counter member are subjected to a longitudinal displacement relative to each other to reach the ejection position.

[0058] Thus, the first and second mechanical codes have two functions: as long as the rotatable member is in a discrete rotational state that does not coincide with a predefined rotational state that corresponds to a predefined size of the dose to be expelled, the first and second mechanical codes block and prevent longitudinal displacement of at least one of the rotatable member and the counter member towards and to the expelling position. In effect, the injection device cannot be switched from the dose setting mode to the dose expelling mode. Moreover, when the rotatable member is in a predefined rotational state in a range of multiple rotational states in which the first mechanical code is longitudinally aligned with the second mechanical code, the mechanical code enables displacement of at least one of the rotatable member and the counter member by a mode switching distance, thus reaching the expelling position in which the rotatable member and the counter member are non-rotatably locked to each other through the first and second mechanical codes.

[0059] In another example, the counter member and the rotatable member are non-rotatably locked when one of the rotatable member and the counter member reaches the ejected position. When the ejected position is reached, the rotatable member and the counter member can also be in axial abutment by the first mechanical cord and the second mechanical cord. Here, the first mechanical cord and the second mechanical cord can also provide a longitudinal abutment between the rotatable member and the counter member. When non-rotatably locked in the ejected position, a torque applied to one of the rotatable member and the counter member is transmitted to the other of the rotatable member and the counter member. For example, if the counter member is rigidly coupled to the housing, the rotatable member is non-rotatably fixed to the housing when the ejected position is reached.

[0060] According to a further example, the counter part is integrated in the housing or the counter part is rigidly coupled to the housing. Here, the rotatable member is formed by the trigger or it is longitudinally displaceable relative to the housing by depressing the trigger distally. In this example, the first cord can be provided at the proximal end of the housing. The second cord can be provided at the distal end of the trigger. The trigger can include a side wall or skirt and the second mechanical cord can be provided on the side wall or skirt of the trigger. Furthermore, the first mechanical cord can include a series of axial recesses and protrusions along the circumference of the proximal front face of the housing. Correspondingly, the trigger can also include a series of axially extending protrusions and recesses along the circumference of the side wall or skirt. In other words, the trigger can include a distally facing crown wheel part or crown wheel portion and the housing can include a correspondingly shaped proximally facing crown wheel part or crown wheel portion. In this manner, the trigger can be non-rotatably locked to the housing when it is depressed distally toward and into the ejection position.

[0061] In a further example, the injection device includes a dose indicator and a drive sleeve. The dose indicator can form a rotatable member and is threadedly engaged with the housing. Here, the drive sleeve can form a counter member and is longitudinally displaceable relative to the housing by distally depressing a trigger. In this example, the rotatable member is rotatable but axially constrained and / or axially fixed to the housing. The counter member formed by the drive sleeve is non-rotatably locked to the housing and cannot rotate relative to the housing as long as the device is in a dose setting mode. Here, the drive sleeve and the dose indicator can constitute a splined engagement provided by first and second mechanical codes. The drive sleeve and the dose indicator can include at least a pair of mutually corresponding radial protrusions and recesses along their inner and outer circumferences.

[0062] Typically, the drive sleeve is located radially inside the dose indicator. The dose indicator comprises, at least in part, a hollow structure for receiving at least a portion of the drive sleeve. At least one radial recess or protrusion is provided on an outer surface of the drive sleeve to engage with a correspondingly shaped radial recess on an inner surface of the dose indicator. The dose indicator is subject to rotation during dose setting, while the drive sleeve is non-rotatably locked to the housing during dose setting. When a dose of the appropriate or predetermined size is set or dialed in, the second mechanical code of the dose indicator longitudinally aligns with a mating member, e.g., the first mechanical code of the drive sleeve, thus enabling longitudinal displacement of the drive sleeve relative to the dose indicator.

[0063] The longitudinal displacement of the drive sleeve, typically in the distal direction towards the ejection position, can be triggered by a trigger. When displacing the drive sleeve distally towards and to the ejection position, a torque-resistant engagement between the drive sleeve and the dose indicator can be established by a first mechanical cord and a second mechanical cord. When the ejection mechanism is implemented as a wind-up ejection mechanism, one of the drive sleeve and the dose indicator is engaged with a mechanical energy store, such as a helically wound torsion spring. Such a mechanical energy store is connected at one end to the housing and further connected at the opposite end to one of the dose indicator and the drive sleeve. As soon as the torque-resistant engagement between the drive sleeve and the dose indicator is established, thereby engaging the clutch, the mechanical energy from the mechanical energy store is released by the release of another clutch or clutch mechanism. Under the action of the depleting mechanical energy store, the dose indicator is then subjected to a dose-reducing rotation relative to the housing, which rotation is equally transmitted to the drive sleeve, thus transmitting a driving force to the piston rod for biasing against the bung of the cartridge.

[0064] According to another example, the injection device includes a cartridge containing a medicament. The cartridge is disposed inside the housing. The injection device can be configured or implemented as a disposable injection device that is intended to be discarded in its entirety once the medicament is expelled through a distal outlet of the cartridge, for example through a needle assembly that pierces a closure at the distal end of the cartridge.

[0065] In this context, the distal end or distal direction refers to the end of the injection device from which the liquid medicament is ejected. The proximal end or proximal direction refers to the end of the injection device that is furthest from the patient's biological tissue that is to be treated with the medicament. The injection device is typically configured for administration of a liquid medicament, such as insulin or heparin. The injection device is typically configured for self-medication. It is configured for operation by only one hand of the user. A trigger, typically provided at the proximal end of the injection device, is configured to be depressed by the user's thumb, while the remaining fingers of the same hand can grip the housing of the injection device.

[0066] The injection device may include a cartridge containing a liquid drug or medicament. By way of example, pressing an injection button causes a portion thereof to be expelled from the cartridge according to a dial setting or a preset amount. The terms "drug" and "medicament" may refer to a pharmaceutical formulation containing at least one pharma-ceutically active compound. Further details regarding specific pharmaceutical formulations may be obtained from the disclosures in co-pending application PCT / EP2018 / 082640, attorney docket no. DE2017 / 081, which are hereby incorporated by reference.

[0067] It is further apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope of the present disclosure as defined by the claims. Furthermore, it should be noted that any reference numbers used in the appended claims shall not be construed as limiting the scope of the present invention.

[0068] In the following, various embodiments of a data collection device in association with an injection device are described with reference to the drawings. [Brief description of the drawings]

[0069] [Figure 1] FIG. 2 is a top view of the drug delivery device of the present invention in the minimum dose position. [Diagram 2] FIG. 2 is an exploded view of the components of the device of FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of the device of FIG. 1. [Figure 4a] FIG. 2 is an enlarged cross-sectional view of a detail of the device of FIG. 1 in a dose setting mode. [Figure 4b] FIG. 2 is an enlarged cross-sectional view of a detail of the device of FIG. 1 in dose dispensing mode. [Diagram 5] FIG. 2 illustrates the interface between the number sleeve and the buttons of the device of FIG. 1. [Figure 6] FIG. 2 illustrates the interface between the housing and the buttons of the device of FIG. 1. [Figure 7a] FIG. 2 shows the interface between the number sleeve and the drive sleeve of the device of FIG. 1 in dose setting mode. [Figure 7b] FIG. 2 illustrates the interface between the number sleeve and the drive sleeve of the device of FIG. 1 in dose dispensing mode. [Figure 8] FIG. 2 shows the interface between the piston rod and the bearing of the device of FIG. 1. [Figure 9] FIG. 2 illustrates the interface between the clutch plate and the button of the device of FIG. 1. [Figure 10] FIG. 2 shows in cross-section the end components of the dose clicker of the device of FIG. 1. [Figure 11a] FIG. 2 shows in an enlarged view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 11b] FIG. 2 shows in an enlarged view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 11c] FIG. 2 shows in an enlarged view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 12a] FIG. 2 shows in enlarged cross-sectional view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 12b] FIG. 2 shows in enlarged cross-sectional view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 12c] FIG. 2 shows in enlarged cross-sectional view the sequence for producing a click at the end of dose dispensing of the device of FIG. 1. [Figure 13] FIG. 2 shows a gauge element of the device of FIG. 1. [Figure 14] FIG. 2 shows a portion of a digit sleeve of the device of FIG. 1. [Figure 15] FIG. 2 shows a further portion of the digit sleeve of the device of FIG. 1. [Figure 16] FIG. 2 shows a portion of a drive spring of the device of FIG. 1. [Figure 17a] FIG. 2 is a top view of the device of FIG. 1 with the 0 unit dialed in. [Figure 17b] FIG. 2 is a top view of the device of FIG. 1 with 96 units dialed in. [Figure 18] FIG. 2 illustrates the interface between the housing and the drive sleeve of the device of FIG. 1. [Figure 19] FIG. 2 illustrates the interface between the clutch plate and the drive sleeve of the device of FIG. 1. [Figure 20] FIG. 2 shows the final dose mechanism of the device of FIG. 1. [Figure 21] FIG. 2 shows a torsion spring of the device of FIG. 1. [Figure 22a] 2A-2C show different embodiments of the thread between the piston rod and the housing of the device of FIG. 1. [Figure 22b] 2A-2C show different embodiments of the thread between the piston rod and the housing of the device of FIG. 1. [Figure 22c] 2A-2C show different embodiments of the thread between the piston rod and the housing of the device of FIG. 1. [Diagram 23] FIG. 1 shows a cross-section of an injection device illustrating only the housing, the driver and the dose indicator. [Figure 24] FIG. 1 shows a cross-section of an injection device in which the driver forms the mating member and the dose indicator forms the rotatable member. [Diagram 25]25 illustrates the rotatable member and the counter member of FIG. 24 when the first and second mechanical cords are aligned and when the injection device is in a dose setting mode. [Figure 26] FIG. 26 shows the arrangement according to FIG. 25 when the device is in ejection mode. [Figure 27] FIG. 26 shows a configuration similar to FIG. 25, in which the first and second cords are not aligned. [Figure 28] FIG. 28 shows the configuration of FIG. 27, in which the first and second mechanical codes prevent the injection device from switching to a dose ejection mode. [Figure 29] 13 is a perspective view of another example of a rotatable member and a mating member with the first and second mechanical cords aligned; FIG. [Diagram 30] FIG. 30 further illustrates the configuration of FIG. 29, with the injection device switched to dose ejection mode. [Diagram 31] FIG. 13 illustrates the rotatable member and the counter member with the first and second mechanical cords out of alignment. [Diagram 32] FIG. 32 shows the configuration of FIG. 31, in which switching of the injection device to the ejection mode is prevented or blocked by the first and second mechanical cords. [Diagram 33] FIG. 13 shows a longitudinal section of a further example of an injection device. [Diagram 34] FIG. 34 is a cross-sectional perspective view of the proximal part of the injection device according to FIG. 33. [Diagram 35] 13 is a further example of an injection device with a counter member and a rotatable part when aligned. [Diagram 36] FIG. 36 shows the example of FIG. 35 when the first and second mechanical cords are not aligned. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] FIG. 1 shows a drug delivery device in the form of an injection pen. The device has a distal end (left end in FIG. 1) and a proximal end (right end in FIG. 1). The component parts of the drug delivery device are shown in FIG. 2. The drug delivery device includes a body or housing 10, a cartridge holder 20, a lead screw (piston rod) 30, a drive sleeve 40, a nut 50, a dose indicator (number sleeve) 60, a button 70, a dial grip or dose selector 80, a torsion spring 90, a cartridge 100, a gauge element 110, a clutch plate 120, a clutch spring 130, and a bearing 140. A needle arrangement (not shown) with a needle hub and a needle cover may be provided as an additional component, which can be replaced as explained above. All components are concentrically located around a common main axis I of the mechanism shown in FIG. 3.

[0071] The housing 10 or body is a generally tubular element with a proximal end having an enlarged diameter. The housing 10 provides a location for the liquid drug cartridge 100 and the cartridge holder 20, windows 11a, 11b for viewing the dose numbers on the number sleeve 60 and the gauge element 110, as well as features on its outer surface, e.g., a circumferential groove, for axially retaining the dose selector 80. The flange-like or cylindrical inner wall 12 includes an internal thread that engages with the piston rod 30. The housing 10 further has at least one internal, axially oriented slot or the like for axially guiding the gauge element 110. In the embodiment shown in the figures, the distal end comprises an axially extending strip 13 that partially overlaps the cartridge holder 20. The figures depict the housing 10 as a single housing component. However, the housing 10 can include two or more housing components that are permanently attached to each other during assembly of the device.

[0072] The cartridge holder 20 is located distally of the housing 10 and is permanently attached thereto. The cartridge holder is a transparent or translucent component that is tubular for receiving the cartridge 100. The distal end of the cartridge holder 20 may be equipped with a means for mounting a needle device. A removable cap (not shown) may be provided for mounting over the cartridge holder 20 or may be retained by a clip feature on the housing 10.

[0073] The piston rod 30 is non-rotatably constrained relative to the drive sleeve 40 by a splined interface. When rotated, the piston rod 30 is forced to move axially relative to the drive sleeve 40 through its threaded interface with the inner wall 12 of the housing 10. The lead screw 30 is an elongated member having external threads 31 (FIG. 3) that engage corresponding threads on the inner wall 12 of the housing 10. The threads 31 may have a large lead-in, e.g., a wedge-shaped profile, at its distal end to engage a corresponding housing thread profile upon initial rotation. The interface includes at least one longitudinal groove or track and a corresponding protrusion or spline 45 on the driver 40. At its distal end, the lead screw 30 engages the clip-mounted bearing 140 of the bearing 140. The interface comprises an interface for the insertion of the lead screw 30 into the distal end of the lead screw 30. In this embodiment, the interface comprises two distally extending clip arms 32, which define an insertion space between them for the insertion of the bearing 140 interface. Alternatively, the interface can comprise only one single clip arm extending more than 180° around the longitudinal axis, or it can comprise one or several clip arms 32. The clip arms 32 can have a bent profile with a recessed clip portion as shown in FIG. 8. Preferably, the clip arms form a cylindrical outer surface at the bottom of the groove (fluted bottom) of the outer thread 31 with a diameter equal to or smaller than the outer diameter of the lead screw 30. A concave contact surface 33 is provided between the clip arms 32 for the abutment of a corresponding portion of the bearing 140.

[0074] The drive sleeve 40 is a hollow member that surrounds the lead screw 30 and is disposed within the numeral sleeve 60. It extends from its interface with the clutch plate 120 to a point of contact with the clutch spring 130. The drive sleeve 40 is axially movable relative to the housing 10, the piston rod 30, and the numeral sleeve 60 in a distal direction against the bias of the clutch spring 130, and in an opposite proximal direction under the bias of the clutch spring 130.

[0075] A splined tooth interface with the housing 10 prevents rotation of the drive sleeve 40 during dose setting. This interface, shown in detail in FIG. 18, includes a ring of radially extending external teeth 41 at the distal end of the drive sleeve 40 and corresponding radially extending internal teeth 14 on the housing component 10. When the button 70 is pressed, these drive sleeve 40 to housing 10 splined teeth 14, 41 are disengaged, allowing the drive sleeve 40 to rotate relative to the housing 10.

[0076] A further splined tooth interface with the number sleeve 60 is not engaged during dial setting, but is engaged when the button 70 is pressed, preventing relative rotation between the drive sleeve 40 and the number sleeve 60 during dosing. In the preferred embodiment shown in Figures 7a and 7b, this interface comprises inwardly facing splines 61 on a flange 62 on the inner surface of the number sleeve 60, and a ring of radially extending external splines 42 on the drive sleeve 40. Corresponding splines 61, 42 are located on the number sleeve 60 and the drive sleeve 40, respectively, so that axial movement of the drive sleeve 40 relative to the (axially fixed) number sleeve 60 engages or disengages the splines to non-rotatably couple or decouple the drive sleeve 40 and number sleeve 60.

[0077] Preferably, the splines 61, 42 are arranged such that they are disengaged when the teeth 41 of the drive sleeve 40 and the internal teeth 14 of the housing component 10 mesh, and engaged when the teeth 41 and the internal teeth 14 disengage. In a preferred embodiment, the splines 61, 42 are longer in the axial direction compared to the teeth 41, 14. This allows the engagement of the splines 61, 42 shortly before the disengagement of the teeth 41, 14. In other words, the splines 61, 42 and the teeth 41, 14 are designed and arranged such that actuation of the button 70 non-rotatably restrains the drive sleeve 40 relative to the numeral sleeve 60 before the drive sleeve 40 is rotated relative to the housing 10. Similarly, when the button 70 is released after dose dispensing, the axial movement of the drive sleeve 40 first non-rotatably restrains the drive sleeve 40 relative to the housing and then decouples the splines 61, 42. As an alternative to the corresponding splines 61, 42, teeth can be provided. As a further alternative, or in addition to the splines 61, 42, the drive sleeve 40 and the number sleeve 60 can be non-rotatably coupled to one another during dose dispensing by a clutch plate 120.

[0078] The interface of the drive sleeve 40 shown in FIG. 1. The clutch plate 120 includes a ring of ratchet teeth 43 located on the face and a corresponding ring of ratchet teeth 121 on the clutch plate 120 .

[0079] The driver 40 has a threaded portion 44 that provides a helical track for the nut 50 (FIG. 20). In addition, a final dose abutment or stop 46 is provided, which is either an end of the thread 44 track or, preferably, a rotating hard stop for interaction with a corresponding final dose stop 51 of the nut 50, thus limiting the movement of the nut 50 on the thread 44. At least one longitudinal spline 45 engages a corresponding track of the lead screw 30. Furthermore, the drive sleeve comprises a ramp 47 that interacts with a clicker arm 67 when the drive sleeve 40 is in its distal position during dose dispensing, i.e., when the button 70 is depressed.

[0080] The final dose nut 50 is located between the number sleeve 60 and the drive sleeve 40. It is non-rotatably constrained relative to the number sleeve 60 by a splined interface (splines 52 on the nut 50). It moves along a helical path relative to the drive sleeve 40 by a threaded interface (threads 44) when relative rotation occurs between the number sleeve 60 and the drive sleeve 40, which is only during dial setting. This is shown in FIG. 20. Alternatively, the nut 50 can be splined to the driver 40 and screwed onto the number sleeve 60. In the embodiment shown in the figures, the nut 50 is a full nut, but in alternative embodiments it may be a half nut, i.e. a component that extends approximately 180° around the central axis of the device. A final dose stop 51 is provided that engages with a stop 46 of the drive sleeve 40 when the dose is set corresponding to the remaining dosable amount of medication in the cartridge 100.

[0081] The dose indicator or number sleeve 60 is a tubular element as shown in Figures 2 and 3. The number sleeve 60 is rotated during dose setting (by the dose selector 80) and dose correction, as well as during dose dispensing by the torsion spring 90. Together with the gauge element 110, the number sleeve 60 defines a zero position ("non-working") and a maximum dose position. The number sleeve 60 may therefore be considered a dose setting member.

[0082] For manufacturing reasons, the number sleeve 60 of the embodiment shown in the figures includes a number sleeve lower portion 60a, which is rigidly secured to the number sleeve upper portion 60b during assembly to form the number sleeve 60. The number sleeve lower portion 60a and the number sleeve upper portion 60b are separate components only to simplify number sleeve 60 tooling and assembly. Alternatively, the number sleeve 60 may be a unitary component. The number sleeve 60 is constrained to the housing 10 by features toward the distal end to allow rotation but not translation. The number sleeve lower portion 60a is marked with a series of numbers that are visible through the gauge element 110 and openings 11a, 11b in the housing 10 to indicate the dialed-in dose of medication.

[0083] Additionally, the numeral sleeve lower portion 60a has a portion with an external thread 63 that engages the gauge element 110. End stops 64, 65 are provided on either end of the thread 63 to limit movement relative to the gauge element 110.

[0084] A clutch feature, in the form of a ring of splines 66 in the embodiment of Figure 5, is provided facing inwardly on the numeral sleeve upper part 60b for engagement with splines 73 of the button 70 during dose setting and dose correction. A clicker arm 67 is provided on the outer surface of the numeral sleeve 60 which interacts with the drive sleeve 40 and the gauge member 110 to generate a feedback signal. In addition, the numeral sleeve lower part 60a is adapted to couple to the nut 50 and clutch by a splined interface including at least one longitudinal spline. It is non-rotatably constrained relative to the plate 120 .

[0085] The interface for attachment of the torsion spring 90 to the lower number sleeve 60a includes a groove feature 68 having a large lead-in and a pocket 69 or anchor point for receiving the first coil or hook portion of the spring. The groove 68 has an end feature in the form of a ramp that is in interference with the hook portion 91 of the spring. The design of the groove 68 is such that the spring 90 can be received in the pocket 69 without interference with the gauge element 110.

[0086] The button 70, which forms the proximal end of the device, is permanently splined to the dose selector 80. A central stalk 71 extends distally from the proximal actuation face of the button 70. The stalk 71 comprises a flange 72 carrying splines 73 for engagement with the splines 66 of the number sleeve top 60b (FIG. 5). It is therefore also splined to the number sleeve top 60b by the splines 66, 73 (FIG. 5) when the button 70 is not pressed, but this spline interface is separated when the button 70 is pressed. The button 70 has a discontinuous annular skirt with splines 74. When the button 70 is pressed, the splines 74 on the button 70 engage with splines on the housing 10 (FIG. 6), preventing rotation of the button 70 (and hence the dose selector 80) during dosing. These splines 74, 15 disengage when the button 70 is released, allowing the dose to be dialed in. Additionally, a ring of ratchet teeth 75 is provided on the inside of flange 72 for interaction with clutch plate 120 (FIG. 9).

[0087] The dose selector 80 is axially constrained to the housing 10. It is non-rotatably constrained to the button 70 by a splined interface. This splined interface, which includes grooves that interact with spline features formed by the annular skirt of the button 70, remains engaged regardless of the axial position of the dose button 70. The dose selector 80, or dose dial grip, is a sleeve-like component with a serrated outer skirt.

[0088] Torsion spring 90 is attached at its distal end to housing 10 and at the opposite end to number sleeve 60. Torsion spring 90 is located inside number sleeve 60 and surrounds the distal portion of drive sleeve 40. As shown in FIG. 16, the spring has a hook 91 at one end for attachment to number sleeve 60. A similar hook end 92 is provided at the opposite end for attachment to housing 10. Torsion spring 90 is pre-wound at assembly such that it applies a torque to number sleeve 60 when the mechanism is at the zero unit dial setting. The act of rotating dose selector 80 to set a dose rotates number sleeve 60 relative to housing 10, further charging torsion spring 90.

[0089] Torsion spring 90 is formed from a helical wire with at least two different pitches. In Figure 21, both ends are formed from "closed" coils 93, i.e., the pitch is equal to the wire diameter and each coil touches the adjacent coil. The center portion has "open" coils 94, i.e., the coils do not touch each other.

[0090] The cartridge 100 is received in the cartridge holder 20 (FIG. 3). The cartridge 100 may be a glass ampoule having a removable rubber stopper 101 at its proximal end. The distal end of the cartridge 100 comprises a pierceable rubber seal that is held in place by a crimped annular metal band. In the embodiment depicted in the figures, the cartridge 100 is a standard 1.5 ml cartridge. The device is designed to be disposable, in that the cartridge 100 cannot be replaced by the user or medical personnel. However, reusable variants of the device may be implemented by removing the cartridge holder 20. This can be provided by allowing the lead screw 30 to be unwound and the nut 50 to be reset.

[0091] The gauge element 110 is constrained relative to the housing 10 by a splined interface to prevent rotation but allow translational movement. The gauge element 110 has a helical feature 111 on its inner surface that engages with a helical thread cut in the numeral sleeve 60 such that rotation of the numeral sleeve 60 causes axial translational movement of the gauge element 110. This helical feature on the gauge element 110 also creates stop abutments 112, 113 against the ends of the helical cut in the numeral sleeve 60 to limit the minimum and maximum doses that can be set.

[0092] The gauge element 110 has a generally plate or band-like component with a central aperture 114 or window and two flanges 115, 116 extending on either side of the aperture. The flanges 115, 116 are preferably not transparent and therefore shield or cover the numeral sleeve 60, while the aperture 114 or window allows a portion of the numeral sleeve lower portion 60a to be viewed. Additionally, the gauge element 110 has a cam 117 and a recess 118 that interact with the clicker arm 67 of the numeral sleeve 60 at the end of dose dispensing (FIGS. 11a-12c).

[0093] As seen in Figures 9 and 19, the clutch plate 120 is a ring-like component. The clutch plate 120 is splined to the number sleeve 60 by splines 122. It is also connected to the drive sleeve 40 by a ratchet interface (ratchet teeth 43, 121). The ratchet provides detent positions between the number sleeve 60 and the drive sleeve 40 corresponding to each dosage unit, engaging different inclined tooth angles during clockwise and counterclockwise relative rotation. A clicker arm 123 is provided on the clutch plate 120 for interaction with the ratchet feature 75 of the button.

[0094] The clutch spring 130 is a compression spring. The axial position of the drive sleeve 40, clutch plate 120 and button 70 is determined by the action of the clutch spring 130 applying a force to the drive sleeve 40 in a proximal direction. This spring force is reacted by the drive sleeve 40, clutch plate 120 and button 70, and when "unloaded" it is reacted through the dose selector 80 to the housing 10. The spring force ensures that the ratchet interface (ratchet teeth 43, 121) is always engaged. In the "unloaded" position, the spring force also ensures that the button spline 73 is engaged with the number sleeve spline 66 and that the drive sleeve teeth 41 are engaged with the teeth 14 of the housing 10.

[0095] The bearing 140 is axially constrained against the piston rod 30 and acts on the bung 101 in the liquid drug cartridge. It is axially clamped to the lead screw 30 but is free to rotate. The bearing 140 includes a disk 141 with a proximally extending shank 142. The shank 142 has a convex contact surface 143 at its proximal end. In addition, a concave portion 144 is provided on the shank 142. The curvature of the convex contact surface 143 and the concave contact surface 33 are selected such that the contact diameter between the bearing 140 and the lead screw 30 is small to minimize friction losses at this interface. The design of the clip interface between the bearing 140 and the lead screw 30 allows the lead screw 30 to be assembled axially from the proximal end and through threaded engagement into the housing 10, thus simplifying assembly. In addition, this design allows for a simple "open and close" type instrument for both components.

[0096] In the "non-operational" state of the device as shown in Figures 4a and 17a, the number slide The probe 60 rests against its zero dose abutments 64, 113 with the gauge element 110 and button 70 undepressed. The dose marking "0" on the number sleeve 60 is visible through windows 11b and 114 in the housing 10 and the gauge element 110, respectively.

[0097] The torsion spring 90, which has some pre-wound turns applied during assembly of the device, applies a torque to the number sleeve 60 and is prevented from rotating by the zero dose abutment 64, 113. Due to the offset between the zero dose stop 64, 113 and the angular offset of the drive sleeve 40 spline teeth, it is also possible to "unwind" the mechanism slightly. This has the effect of preventing potential weepage when the dose is dialed in and the zero dose abutment is disengaged.

[0098] Automated assembly of the torsion spring 90 into the number sleeve 60 can be accomplished by incorporating large lead-in and groove features into the number sleeve 60. When the torsion spring 90 is rotated during assembly, the hook end form 91 rotates within the groove feature before engaging the anchor point in the number sleeve 60. It is possible to create an interference, or one-way clip feature, between the torsion spring 90 and the number sleeve 60 to help prevent the torsion spring 90 from disengaging the anchor point 69 during a subsequent assembly step.

[0099] The user selects a variable dose of liquid medication by rotating the dose selector 80 clockwise, thereby producing an identical rotation in the number sleeve 60. The rotation of the number sleeve 60 causes the torsion spring 90 to charge, increasing the energy stored therein. As the number sleeve 60 rotates, the gauge element 110 translates axially due to its threaded engagement, thereby indicating the value of the dialed-in dose. The gauge element 110 has flanges 115, 116 on either side of the window area 114 that cover the numbers printed on the number sleeve 60 adjacent to the dialed-in dose to ensure that only the set dose number is visible to the user.

[0100] A particular feature of the present invention is the inclusion of a visual feedback function in addition to the discrete dose numeric display typical in this type of device. The distal end (flange 115) of the gauge element 110 creates a sliding scale through a small window 11a in the housing 10. Alternatively, the sliding scale can be formed using a separate component that is engaged with the numeric sleeves 60 on different helical tracks.

[0101] When a dose is set by the user, the gauge element 110 translates axially a distance that is moved in proportion to the size of the dose setting. This function provides clear feedback to the user regarding the approximate size of the dose setting. Because the dispensing speed of an automatic injector mechanism may be higher than a manual injection device, it may not be possible to read the numerical dose indication during dispensing. The gauge function provides feedback to the user during dispensing regarding the progress of the dose without having to read the dose number itself. For example, the gauge indication can be formed by an opaque element on the gauge element 110 that exposes a component of a contrasting color directly underneath. Alternatively, the exposable element can be printed with an approximate dose number or other indicator to provide a more precise answer. In addition, the gauge indication simulates a syringe action during dose setting and dispensing.

[0102] Openings 11a, 11b in housing 10 allow the user to view the gauge functions and numerical display, as shown in Figures 17a and 17b. To reduce dust ingress and to prevent the user from touching the moving parts, these openings 11a, 11b are covered by semi-transparent windows. While these windows could be separate components, in this embodiment they are assembled into housing 10 using "twin shot" molding techniques. A first shot of translucent material forms the internal features and windows 11a, 11b, then a "second shot" of opaque material forms the outer cover of the housing 10.

[0103] The mechanism utilizes a dose selector 80 that has an increased diameter relative to the housing 10 to aid in dialing, although this is not a requirement of the mechanism. This feature is particularly beneficial (but not essential) for auto-injector mechanisms where the power source is charged during dose setting and the torque required to rotate the dose selector 80 may be higher than in non-automatic injection devices.

[0104] The drive sleeve 40 is prevented from rotating when the dose is set and the number sleeve 60 is rotated due to the engagement of its splined teeth 41 with the teeth 14 of the housing 10. Therefore, relative rotation must occur between the clutch plate 120 and the drive sleeve 40 via the ratchet interfaces 43, 121.

[0105] The user torque required to rotate the dose selector 80 is the sum of the torque required to wind the torsion spring 90 and the torque required to loosen the ratchet interface 43, 121. The clutch spring 130 is designed to provide an axial force to the ratchet interface 43, 121 and to bias the clutch plate 120 onto the drive sleeve 40. This axial load acts to maintain the ratchet teeth engagement of the clutch plate 120 and the drive sleeve 40. The torque required to loosen the ratchet 43, 121 in the dose setting direction is a function of the axial load applied by the clutch spring 130, the clockwise ramp angle of the ratchet teeth 43, 121, the coefficient of friction between the mating surfaces, and the average radius of the ratchet interface 43, 121.

[0106] When the user rotates the dose selector 80 sufficiently to increment the mechanism by one increment, the number sleeve 60 rotates one ratchet tooth relative to the drive sleeve 40. At this point, the ratchet teeth 43, 121 re-engage into the next detent position. An audible click is produced by the ratchet re-engagement and tactile feedback is provided by the change in required torque input.

[0107] Relative rotation of the number sleeve 60 and the drive sleeve 40 is permitted when the splines 42, 61 are disengaged during dose setting. This relative rotation also causes the final dose nut 50 to move along its thread path towards its final dose abutment on the drive sleeve 40.

[0108] If no user torque is applied to the dose selector 80, the number sleeve 60 is then prevented from rotating back under the torque applied by the torsion spring 90 only by the ratchet interface 43, 121 between the clutch plate 120 and the drive sleeve 40. The torque required to loosen the ratchet in the counterclockwise direction is a function of the axial load applied by the clutch spring 130, the counterclockwise ramp angle of the ratchet, the coefficient of friction between the mating surfaces, and the average radius of the ratchet features. The torque required to loosen the ratchet must be greater than the torque applied by the torsion spring 90 to the number sleeve 60 (and therefore the clutch plate 120). Therefore, the ratchet ramp angle is increased in the counterclockwise direction to ensure that this occurs while ensuring that the dial-up torque is as low as possible.

[0109] The user can then choose to increase the selected dose by continuing to rotate the dose selector 80 in a clockwise direction. The process of loosening the ratchet interface 43, 121 between the number sleeve 60 and the drive sleeve 40 is repeated for each dose increment. Additional energy is stored within the torsion spring 90 for each dose increment, potentially increasing the dose. Audio and tactile feedback is provided for each dialed increment by re-engagement of the ratchet teeth. The torque required to rotate the dose selector 80 increases as the torque required to wind the torsion spring 90 increases. Thus, the torque required to unwind the ratchet in a counterclockwise direction must be greater than the torque applied to the number sleeve 60 by the torsion spring 90 when the maximum dose is reached.

[0110] If the user continues to increase the selected dose until the maximum dose limit is reached, the number sleeve 60 engages its maximum dose abutment 65 on the maximum dose abutment 112 of the gauge element 110. This prevents further rotation of the number sleeve 60, the clutch plate 120 and the dose selector 80.

[0111] Depending on the number of increments already delivered by the mechanism, during dose selection the final dose nut 50 may bring its final dose abutment 51 into contact with the stop surface 46 of the drive sleeve 40. The abutment prevents further relative rotation between the number sleeve 60 and the drive sleeve 40, thus limiting the dose that can be selected. The position of the final dose nut 50 is determined by the total number of relative rotations between the number sleeve 60 and the drive sleeve 40 that have occurred each time the user sets a dose.

[0112] When the mechanism is in a state where a dose has already been selected, the user can deselect any number of increments from this dose. Deselecting a dose is accomplished by the user rotating the dose selector 80 counterclockwise. The torque applied by the user to the dose selector 80, when combined with the torque applied by the torsion spring 90, is sufficient to loosen the ratchet interface 43, 121 between the clutch plate 120 and the drive sleeve 40 in a counterclockwise direction. When the ratchet is loosened, a counterclockwise rotation is induced in the number sleeve 60 (through the clutch plate 120), which returns the number sleeve 60 towards the zero dose position and unwinds the torsion spring 90. The relative rotation between the number sleeve 60 and the drive sleeve 40 causes the final dose nut 50 to move back along its helical path away from the final dose abutment.

[0113] With the mechanism in a state where a dose is already selected, the user can activate the mechanism to begin delivery of the dose, which is initiated by the user depressing button 70 axially distally.

[0114] When the button 70 is depressed, the splines between the button 70 and the number sleeve 60 disengage, non-rotatably decoupling the button 70 and dose selector 80 from the delivery mechanism, i.e., from the number sleeve 60, the gauge element 110, and the torsion spring 90. The splines 74 on the button 70 engage with the splines 15 on the housing 10, preventing rotation of the button 70 (and thus the dose selector 80) during dosing. Because the button 70 is stationary during dosing, it can be used in a dosing clicker mechanism, as shown in FIG. 9. A stop feature in the housing 10 limits the axial movement of the button 70, reducing the risk of damaging internal components in response to any erroneous axial load applied by the user.

[0115] The clutch plate 120 and drive sleeve 40 move axially with the button 70. This engages the splined tooth interface 42, 61 between the drive sleeve 40 and the number sleeve 60 to prevent relative rotation between the drive sleeve 40 and the number sleeve 60 during dispensing, as shown in Figure 7a (splines 42, 61 disengaged) and Figure 7b (splines 42, 61 engaged). The splined tooth interface 41, 14 between the drive sleeve 40 and the housing 10 is disengaged, thus preventing relative rotation between the drive sleeve 40 and the number sleeve 60 during dispensing. The drive sleeve 40 is then able to rotate and is driven by the torsion spring 90 via the number sleeve 60 and the clutch plate 120 .

[0116] Rotation of the drive sleeve 40 causes the piston rod 30 to rotate due to the splined engagement, which in turn advances due to its threaded engagement into the housing 10. The number sleeve 60 rotation also causes the gauge element 110 to traverse axially back to its zero position whereby the zero dose abutments 64, 113 stop the mechanism.

[0117] The bearing 140 is axially clamped to the piston rod 30 but is free to rotate. Because the bearing 140 is in direct contact with the bung 101, it does not rotate as the piston rod 30 rotates and advances during dose dispensing. As explained above, the contact diameter between the bearing 140 and the piston rod 30 is small to minimize friction losses at this interface. The design of the piston rod 30 and bearing 140 eliminates the delicate clip function or large contact diameter present in previous concepts. This embodiment also allows the piston rod 30 to be assembled axially from the proximal end and through thread engagement into the housing 10, thus simplifying assembly.

[0118] Tactile feedback during dose dispensing is provided via a compliant cantilever clicker arm 123 integrated within the clutch plate 120. This arm 123 radially interfaces with a ratchet feature 75 on the inner surface of the button 70 such that the ratchet tooth spacing corresponds to the number sleeve 60 rotations required for a single incremental dose. During dispensing, as the number sleeve 60 rotates and the button 70 is non-rotatably coupled to the housing 10, the ratchet feature 75 engages the clicker arm 123 to produce an audible click-on as each dose increment is delivered.

[0119] Dose delivery continues due to the mechanical interactions described above while the user continues to depress button 70. When the user releases button 70, clutch spring 130 returns drive sleeve 40 (along with clutch plate 120 and button 70) to its "non-running" position, engaging splines 14, 41 between drive sleeve 40 and housing 10 to prevent further rotation and stop dose delivery.

[0120] During dose delivery, the drive sleeve 40 and number sleeve 60 rotate together so that no relative motion occurs in the final dose nut 50. Thus, the final dose nut 50 moves axially relative to the drive sleeve 40 only during dial setting.

[0121] Once dose delivery has been stopped by returning the number sleeve 60 to the zero dose abutment, the user can release the button 70 which will re-engage the spline teeth 14, 41 between the drive sleeve 40 and the housing 10. The mechanism is then returned to the "non-operated" state.

[0122] It is possible to adjust the angle of the spline teeth 14, 41 on either the drive sleeve 40 or the housing 10 so that when the button 70 is released, re-engagement of the spline teeth 14, 41 very slightly "unwinds" the drive sleeve 40, thereby removing the engagement of the number sleeve 60 against the zero dose stop abutment on the gauge element 110. This compensates for the effects of clearances in the mechanism (e.g. due to tolerances) which could otherwise cause slight advancement of the piston rod 30 and drug dispensing when the device is dialed for a subsequent dose due to the number sleeve 60 zero dose stop not arresting the mechanism and instead a restraining force back on the splines between the drive sleeve 40 and the housing 10.

[0123] At the end of dose dispensing, additional audible feedback is provided in the form of a "click" distinct from the "click" provided during dispensing to inform the user that the device has returned to its zero position via the interaction of the clicker arm 67 on the number sleeve 60 with the ramp 47 on the drive sleeve 40 and the cam 117 and recess 118 on the gauge element 110. This embodiment allows feedback to be made only at the end of dose delivery and not when the device is dialed back or away from the zero position.

[0124] 11a shows the position of the click feature when the device is in the "unactivated" state with the zero unit dialed in and the button 70 not depressed. It can be seen that the cam feature 117 on the gauge element 110 does not contact the clicker arm 67 on the number sleeve 60 when the button 70 is in the "unactivated" state, and therefore the clicker arm 67 is not displaced during storage or dialing.

[0125] During dial setting, the gauge element 110 translates proximally so that the cam 117 is no longer axially aligned with the clicker arm 67. At the start of dose delivery when the drive sleeve 40 translates distally, the ramp 47 on the drive sleeve 40 pushes the clicker arm 67 radially outward. During dose delivery, the gauge element 110 translates back distally and towards the end of dose delivery the clicker arm 67 contacts the cam 117 on the gauge element 110. For small doses, the cam 117 and clicker arm 67 are in contact at the start of the dose. Figures 11b-12c show the component interaction. After dose delivery the button 70 is released and the end of the dose mechanism returns to its "non-worked" position.

[0126] In Figure 11b, the dose is dialed in and approximately one full dial revolution is applied to the number sleeve 60. The gauge element 110 is translated axially away from the zero unit position so that the cam 117 is no longer axially aligned with the clicker arm 67. Figure 11c shows the start of dispensing where the button 70 is depressed to initiate dose dispensing, axially translating the drive sleeve 70. The ramp 47 on the drive sleeve 40 pushes the clicker arm 67 radially outwards into radial alignment with the cam 117 on the gauge element 110.

[0127] FIG. 12a shows the mechanism at the end of dose dispensing with approximately 4 units remaining. The gauge element 110 moves axially back towards its zero unit position, so that the cam 117 axially aligns with the clicker arm 67. Rotation of the number sleeve 60 brings the clicker arm 67 into contact with the cam 117, so that the clicker arm 67 is pushed radially inwards. With approximately 2 units remaining, the number sleeve 60 rotates further and the clicker arm 67 follows the contour of the cam 117 (FIG. 12b). This radial displacement "charges" the clicker arm 67 which stores elastic energy. In FIG. 12c, dispensing is completed when the number sleeve 60 reaches its zero unit rotation position. The clicker arm 67 moves off the sharp edge of the cam 117 into the recess 118. The elastic energy is released, causing clicker arms 67 to spring radially outward into contact with cam 117, generating a distinct "click."

[0128] In the primary embodiment of the invention, the lead screw 30 advances by a fixed displacement per revolution of the drive sleeve 40. In other embodiments, the rate of displacement varies. For example, the lead screw 30 may advance a large displacement per revolution to dispense a first amount of drug from the cartridge 100, and a smaller displacement per revolution to dispense the remainder of the cartridge 100. This compensates for the fact that for a given displacement of the mechanism, the first dose dispensed from the cartridge 100 often has a smaller volume than the other doses. This is advantageous because it allows

[0129] 22 shows three embodiments with the circumferential projection of the threads 16 of the housing 10 and the threads 31 of the lead screw 30. The arrow R indicates the direction of rotation of the lead screw 30 relative to the housing 10 for all three figures.

[0130] In FIG. (a) is the main embodiment, where the pitch is equal on the housing 10 and the lead screw 30, so the lead screw 30 advances a fixed amount with each revolution of the drive sleeve 40. In FIG. (b) the first turn of the threads 31 on the lead screw 30 has a large pitch and the other turns have small pitches. During the first revolution, the lead screw 30 displacement depends on the large pitch of the first turn of the threads 31 on the lead screw 30, so it displaces a large amount per revolution. In the subsequent revolutions, the lead screw 30 displacement depends on the smaller pitch of the lead screw threads 31, so it displaces a smaller amount. In FIG. (c) the threads 16 on the housing 10 have a larger pitch than the lead screw 30. During the first revolution, the lead screw 30 displacement depends on the pitch of the housing threads 16, so it displaces a larger amount per revolution. On subsequent revolutions, the lead screw 30 displacement depends on the pitch of the lead screw threads 31, so it displaces by a smaller amount.

[0131] In one embodiment, the drug delivery device includes a dose setting mechanism for setting a minimum dose size. Such a dose setting mechanism must ensure that the user cannot dispense less medication than required.

[0132] As already explained above, the drug delivery device includes a number sleeve 60 that rotates in one direction, the dose setting direction, during dose setting. The number sleeve 60 rotates in the opposite direction during dispensing or correcting the set dose. The gauge element 110 engages threads 63 on the number sleeve 60, resulting in an axial movement in the dose setting direction during setting and in the opposite direction during dispensing or correcting.

[0133] 23, the spline engagement between the driver 40 and the dose indicator 60 is illustrated in further detail. The driver 40 includes radially outwardly extending lines 42 in the form of protrusions that engage correspondingly shaped splines 61 protruding from the inner surface of the hollow shaped dose indicator 60 or number sleeve.

[0134] In figures 24 to 28 an example of an injection device 1 is illustrated in which the driver 40 forms the counter member 240 and the dose indicator 60 forms the rotatable member 260 in the sense of the appended claims. As explained above, the injection device 1 is switchable between a dose setting mode in which one of the rotatable member 260 and the counter member 240 is in a proximal dose setting position s and a dose ejection mode in which the respective component, e.g. the rotatable member 260 or the counter member 240, is displaced longitudinally l to an ejection position e. In the example of figures 24 to 28, the rotatable member 260 forms the dose indicator 60. The rotatable member 260 is equivalent to the dose indicator 60 as explained above. It is substantially identical to the dose indicator 60 except for the second mechanical code 262, as explained in more detail below. The counter member 240 is equivalent to the driver 40 as explained above. The counter member 240 is substantially identical in shape to the driver 40 except for the second mechanical code. The counter member 240 includes a first mechanical cord 242 that differs from the geometry of the driver 40 as described above in connection with Figures 1-23. The rotatable member 260 includes or forms a digit sleeve 60 that is threadably engaged with the housing 10 as described above. The rotatable member 260 is axially fixed to the housing 10.

[0135] In the example of FIGS. 24 to 28, the driver 40 is a driver for use as shown in FIGS. 25 and 27. It is longitudinally displaceable between a quantity setting position s and a dose ejection position e as illustrated in Figure 26. The radially outwardly projecting portion can engage a peripheral or annular groove on the inside of the side wall of the housing 10 as illustrated in Figures 4a and 4b.

[0136] As illustrated in FIGS. 24-28, the rotatable member 260 includes a second mechanical cord 262. The counter member 240 includes a first mechanical cord 242. As illustrated in FIG. 24, each of the first mechanical cord 242 and the second mechanical cord 262 includes a first cord feature 245, 265. The first cord feature 245 of the first mechanical cord 242 includes at least one of a protrusion 246 and a recess 248. In the example illustrated in FIG. 24, the first cord feature 245 of the first mechanical cord 242 includes both a radial protrusion 246 and a radial recess 248.

[0137] The first cord feature 265 of the second mechanical cord 262 also includes at least one of a protrusion 266 and a recess 268. In an example as illustrated in FIG. 24, the first cord feature 265 of the second mechanical cord 262 includes both a radial protrusion 266 and a radial recess 268. The recesses 248, 268 and the protrusions 246, 266 are of complementary shapes. The protrusion or protrusion of one of the counter member 240 and the rotatable member 260 matches the recess or recess 248, 268 of the other of the counter member 240 and the rotatable member 260. The rotatable member 260 and the counter member 240 can be arranged in a nested or radially overlapping configuration. As illustrated in FIGS. 24-28, the rotatable member 260 includes at least a hollow portion configured to slidably receive at least a portion of the counter member 240. As illustrated in FIGS. 25-28, the counter member 240 may be located entirely inside a hollow sleeve-shaped portion of the rotatable member 260. As illustrated in FIGS.

[0138] In other examples not currently illustrated, the counter member 240 can include a hollow portion configured to slidably receive at least a portion of the rotatable member 260 .

[0139] In the illustrated example, the rotatable member 260 includes at least a first cord feature 265 inside a hollow portion of a sidewall of the rotatable member 260. Correspondingly, the counter member 240 includes a first cord feature 245 on an outer surface of the sidewall.

[0140] As further illustrated in FIG. 24, the first mechanical cord 242 includes a first cord feature 245 and a second cord feature 245'. And, the second mechanical cord 262 includes a first cord feature 265 and a second cord feature 265'. The first and second cord features 245, 245' of the counter member 240 are disposed at a predetermined angular distance from each other on the outer circumference or surface of the counter member 240. Correspondingly, the first and second cord features 265, 265' of the second mechanical cord 262 are located and disposed at a predetermined distance from each other along the inner circumference of the rotatable member 260. As illustrated in FIG. 24, the angle or circumferential distance between the first and second cord features 245, 245' of the first mechanical cord 242 is equal to the angle or circumferential distance between the first cord feature 265 and the second cord feature 265' of the second mechanical cord 262.

[0141] In a further example, the first and second cord features 245, 245′ of the first mechanical cord 242 can be equidistantly or equiangularly positioned around the circumference of the mating member 240. Similarly, the first and second cord features 265, 265′ of the second mechanical cord 262 can be equidistantly or equiangularly positioned around the inner circumference of the rotatable member 260.

[0142] As further illustrated in FIGS. 25 and 27, the protrusions 246 of the first mechanical cord 242 project radially outward and form longitudinally extending ribs around the outer periphery of the mating member 240. The ribs or protrusions 246 are formed by adjacently located recesses 248 which extend radially inwardly and form longitudinally elongated grooves in the outer periphery of the mating member 240.

[0143] Corresponding to the shape of the first mechanical cord 242, the second mechanical cord 262 on the inner surface of the rotatable member 260 includes a radial recess 268 configured to receive the radial protrusion 246. The radial recess 268 may include an elongated groove on the inner surface of the rotatable member 260. The recess 268 is circumferentially limited by at least one protrusion 266 configured to engage the recess 248 of the counter member 240.

[0144] The circumferential extensions of the corresponding projections 246,266 and recesses 248,268 are substantially equal such that the projections 246,266 almost entirely fill the hollow spaces defined by the corresponding recesses 248,268.

[0145] 24, the first and second cord features 245, 245' of the first mechanical cord 248 are symmetrical with respect to the center of the tubular counter member 240. The first and second cord features 265, 265' of the second mechanical cord 262 are also symmetrical with respect to the center of the sleeve or hollow shaped rotatable member 260. Thus, the first and second mechanical cords 242, 262 are invariant to a 180° rotation about the main or longitudinal axis l.

[0146] As explained above, the rotatable member 260 is rotatable in the dose increment direction during dose setting. During dose setting, and due to the ratcheting engagement of the clutch plate 120 with the mating member 240 at the proximal end of the mating member 240 as explained above in connection with the driver 40, which is actually represented by the mating member 240, the rotatable member 260 is rotatable into one of a number of discrete rotational states. The discrete rotational states are governed and determined by the step size of the ratcheting engagement between the clutch plate 120 and the mating member 240. In one example, and during one revolution of the rotatable member 260, it is in one of 24 discrete rotational states relative to the housing 10.

[0147] When the injection device 1 is in the dose setting mode s, the rotatable member 260 is rotatable as described above for setting a dose. During the setting of a dose, the first and second mechanical cords 242, 262 are axially offset. They are axially separated and disengaged. Switching the device to the dose ejection mode e and displacing the counter member 240 from the proximal dose setting position s to the distal dose ejection position e is only possible if the first mechanical cord 242 is longitudinally aligned with the second mechanical cord 262. Such an alignment is illustrated in FIG. 25, where the first and second cord features 265, 265′ of the second mechanical cord 262 of the rotatable member 260 are located in the same angular position compared to the first and second cord features 245, 245′ of the first mechanical cord 242 of the counter member 240.

[0148] In this particular pre-defined rotational state of the rotatable member 260, the counter member 240 can be displaced axially, e.g., in the distal direction 2, such that the first and second mechanical cords 245, 245' of the counter member 240 engage and overlap the first and second cord features 265, 265' of the rotatable member 260. Due to the symmetrical geometry and equidistant arrangement of the first and second cord features 245, 245' and 265, 265', there are now provided two permissible or pre-defined rotational states per revolution of the rotatable member 260 in which the injection device 1 can be switched from the dose setting mode to the dose ejection mode.

[0149] In the currently illustrated example, there are two different rotational states of the counter member 240 per revolution that can trigger the dose ejection procedure. In this embodiment, mismatch of the first and second mechanical cords 244, 262 and / or a rotational state of the second mechanical cord 262 out of alignment with respect to the first mechanical cord 242 will prevent distal displacement of the counter-member 240 to the dose ejection position e. This is illustrated by a comparison of Figures 27 and 28.

[0150] In FIG. 27, the first mechanical cord 242 is misaligned with respect to the second mechanical cord 262. As a result, and when a user attempts to displace the counter member 240 to the ejection position e, the misalignment of the first and second mechanical cords 242, 262 results in a configuration in which the abutment surface 264 of the rotatable member 260 abuts the abutment surface 244 of the counter member 240. The abutment portion 264 includes an abutment surface facing in a proximal direction. The abutment portion 244 or the abutment surface faces in a distal direction. The abutment portion 264 can be located at a longitudinal end of the rotatable member 260 facing towards the counter member 240. The abutment portion 244 of the counter member 240 is located at a longitudinal end of one of the projections 246 facing towards the rotatable member 260.

[0151] In particular, the abutment portion 264 or abutment surface can be located at the proximal end of the protrusion 266, and the abutment portion 244 or abutment surface is typically located at the distal end of the protrusion 246. In the event of a rotational misalignment between the first mechanical cord 242 and the second mechanical cord 262, the counter member 240 cannot be longitudinally displaced such that the first and second mechanical cords 242, 262 engage with each other in a torque-resistant manner. Any further distal displacement of the counter member 240, and thus the button or trigger 70, is effectively blocked and cannot trigger a dose dispensing or dose ejection procedure.

[0152] Another example of a combination of a rotatable member 360 and a counter member 340 is illustrated in Figs. 29-32. The ejection mechanism 4 and the dose setting mechanism 5 of this injection device are somewhat identical to the ejection mechanism 4 and the dose setting mechanism 5 as described above in relation to Figs. 1-23. Here, the rotatable member 360 is substantially equivalent or identical to the button 70 as described above. The counter member 340 is substantially equivalent or identical to the housing 10 as described above. To implement the example of Figs. 29-32, only minor modifications are required to the button 70 and / or the housing 10 to convert the button 70 into the rotatable member 360 and the housing 10 into the counter member 340, as described below. Only minor modifications to the housing 10 and / or the button 70 are required.

[0153] As illustrated in Fig. 29, the rotatable member 360 forms the button 70 of the injection device 1. The rotatable member 360 or button 360 comprises a planar proximal end face 370 and an annular skirt 371 extending from the outer periphery of the end face 370 in the distal direction 2. On the skirt 371, and thus at the distal end of the rotatable member 360, a second mechanical cord 362 is provided which is of complementary shape to the first mechanical cord 342 at the proximal end of the counter member 340 or of the respective housing 310. To initiate or control a dosing operation, the rotatable member 360 or button 70 must be displaced from a dose setting position s as illustrated in Fig. 29 to an ejection position e as illustrated in Fig. 30.

[0154] The proximal end surface of the housing 310 includes a first mechanical cord 342. The first mechanical cord 342 includes a first cord feature 345 and a second cord feature 345'. Each of the first and second mechanical cord features 345, 345' includes a protrusion 346 and a recess 348. The second mechanical cord 362 of the rotatable member 360 also includes a first mechanical cord feature 365 and a second mechanical cord feature 365'. Each of the first and second cord features 365, 365' includes at least one protrusion 366 and a recess 368. The protrusion 366 is shaped to engage with the recess 348. The recess 368 is shaped to engage with the protrusion 346. In contrast to the example illustrated in FIGS. 24-28, the second mechanical cord 362 of the rotatable member 360 ... In the example, the protrusions and recesses 346, 366, 348, 368 extend in a longitudinal or axial direction.

[0155] Generally, the first mechanical cord 342 replaces and modifies the splines 15 provided on the proximal end of the housing 10 as illustrated in Figure 6. The first mechanical cord 342 and / or the second mechanical cord 362 can each include a toothed structure or a crown wheel structure.

[0156] It is further evident in Figures 29-32 that these protrusions 366 project at least slightly radially outward from the skirt extension 373. This longitudinally extending radial protrusion can engage a correspondingly shaped longitudinal groove on the inner surface of the dose selector 80 or dial grip. In this manner, the button 70 and dial grip or dose selector 80 are permanently locked against rotation. The radially outwardly extending protrusions of the skirt extension 377 are also shown in Figure 6.

[0157] Moreover, the projections 346, 366 and the recesses 348, 368 are tapered in the longitudinal direction. The projections 366 are tapered in the distal direction 2. The projections 346 are tapered in the proximal direction 3. In other words, the second mechanical cord 362 includes a toothed or geared structure and the first mechanical cord 342 includes a correspondingly shaped toothed or geared structure. Circumferentially offset from the first and second cord features 345, 345', 365, 365' is provided the abutment surface 344, for example provided on the proximally raised rib 372. In this manner, and in an annular position of the rotatable member 360 in which the second mechanical cord 362 is not aligned with the first mechanical cord 342, distal displacement of the rotatable member 360 relative to the housing 310 or relative to the counter member 340 is blocked by axial abutment of one of the protrusions 366 with the abutment surface 344 of the counter member 340.

[0158] This situation is illustrated diagrammatically in Figure 32, where the distal end of the protrusion 366 of the rotatable member 360 functions equally well, providing an abutment structure or surface 364. In the event of improper alignment, or misalignment of the first and second mechanical cords 342, 362, depression of the rotatable member 360 towards the dose ejection position e is effectively blocked.

[0159] Only in the rotated state of the rotatable member 360, in which the second mechanical cord 362 is longitudinally aligned with the first mechanical cord 342, is a distal forward movement of the mating member 360 permitted and supported. At this time, and when correctly aligned, the protrusions and recesses 366, 368 of the second mechanical cord 362 engage with the correspondingly shaped protrusions and recesses 346, 348 of the second mechanical cord 342. The protrusions 366 can slide axially into the recesses 348. The protrusions 346 can slide into the recesses 368. As a result, the rotatable member 360 can be advanced and displaced distally and to the dose ejection position e in order to switch the injection device 1 from the dose setting mode to the dose dispensing mode as described above in relation to Figs. 1-23.

[0160] In both the example as illustrated in Figures 24-28 and the example as illustrated in Figures 29-32, the rotatable member 260, 360 and the counter member 240, 340 are non-rotatably locked and engaged in a torque-resistant manner when the first and second mechanical cords 242, 342, 262, 362 are correctly aligned and one of the counter member 240 and the rotatable member 360 reaches the dose ejection position e. In this manner, the first and second mechanical cords 242, 342, 262, 362 provide two functions. When in misalignment, the first and second mechanical cords 242, 342, 262, 362 When properly aligned, the first and second mechanical cords 242, 342, 262, 362 not only enable and support switching of the device to a dose ejection mode, but also non-rotatably lock or non-rotatably couple the rotatable member 260, 360 to the mating member 240, 340.

[0161] In the dose ejection mode, and in the example of Figures 24-28, the counter member 240 is rotated by the rotatable member 260 in the dose increment direction under the action of the depleting torsion spring 90, thus transmitting the driving torque to the lead screw 30 or piston rod. In the example of Figures 29-32, the torque-resistant engagement between the rotatable member 360 and the counter member 340 prevents rotational movement of the rotatable member 360, and thus of the trigger 70, relative to the housing 310 during the dose ejection procedure.

[0162] In both examples as illustrated in Figs. 24-32, several permissible orientations can be individually set by adapting the geometry of the first and second mechanical cords 242, 342, 262, 362. Basically, the blocking of the dose setting illustrated above can generally be achieved when the first mechanical cord 242, 342 and the second mechanical cord 262, 362 include at least one cord feature. However, it may be beneficial to have two or more cord features along the circumference of the first and second mechanical cords 242, 342, 262, 362. In the case of blocking the longitudinal movement of one of the rotatable member 360 and the counter member 240, the presence of multiple, for example two or more, mutually engaging abutment surfaces 244, 344, 264, 364 is beneficial to distribute the mechanical load acting in the respective longitudinal direction between the counter member 240, 340 and the rotatable member 260, 360.

[0163] The permissible or predetermined orientations of the rotatable member at which dose ejection is permitted must be equally spaced around the circumference of the rotatable member. This ensures that the size of a predetermined dose does not change after each dispensing or ejection procedure.

[0164] For robustness of the mechanism as illustrated in Figures 24-32, it is beneficial for the number of convexities of one of the first and second mechanical cords 242, 342, 262, 362 to be the same as the number of concaves of the other one of the first and second mechanical cords 242, 342, 262, 362. The torque to be transmitted across the interface of the counter member 240, 340 and the rotatable member 260, 360 is then divided between the number of convexities and concaves available.

[0165] Having a large number of interengaging cord features along the circumference of the first and second mechanical cords 242, 342, 262, 362 may further be beneficial to prevent tilting or off-center movement of at least one of the counter member 240 and the rotatable member 360 when these components are subjected to a longitudinal displacement towards the ejection position e. Provided that the longitudinally displaceable components of the injection device are sufficiently prevented from tilting or off-center movement, some of the protrusions 246, 266, 346, 366 can be removed, resulting in the same selectable dose method. A reduced number of protrusions on the rotatable member 260 or of the dose indicator or number sleeve 60 may have the advantage that only the counter member 240 or the driver 40 has to be modified compared to the implementation of Figs. 1-23.

[0166] It may further be beneficial to add material to and remove material from the rotatable member 260 so that assembly of the mating member 240, and therefore the driver 40, with the rotatable member 260, and therefore with the number sleeve or dose indicator 60, is not inhibited. Modifications to the driver 40 do not affect the general handling and assembly process of the remaining components of the injection device 1. Hence, one and the same fully automated or semi-automated assembly line can be used to produce a variety of injection devices featuring different acceptable dose sizes.

[0167] The same arguments and benefits apply to the examples of Figs. 24-32. Here too, the number of allowed orientations of the rotatable member 360 can be set and applied by the geometry of the mutually corresponding first and second mechanical codes 342, 362. Here too, the allowed orientations must be equally spaced around the circumference of the housing 310 to ensure that the allowed doses do not change after each dispensing procedure. For the robustness of the mechanism, it is advantageous that for each convex portion 366 of the rotatable member 360, a matching notch or recess 348 of the housing 310 is provided, or vice versa. In this manner, the clutch torque or holding force transmitted from the housing 310 to the rotatable member 360 can be divided between the number of teeth and the number of convex portions. Furthermore, the stopping force or axial abutment force for blocking or preventing dispensing can also be divided between the number of teeth and the number of abutment surfaces 344, 364 for each non-allowed angular orientation of the rotatable member 360.

[0168] Provided that the rotatable member 360 is sufficiently prevented from tilting, some of the projections 366 can be removed, thus resulting in the same selectable dose method. The reduced number of teeth or projections 366 can have the advantage that only the housing 310 needs to be modified, compared to the example of the button 70 in FIG. 5. In this way, the modifications required to implement the prevention of an unexpected ejection procedure do not affect other functions used during the assembly of the remaining components of the injection device. Thus, one and the same assembly line can produce a wide range of injection devices featuring different allowable dose sizes. For this, only one of the various housings 310 featuring different mechanical codes 342 has to be selected.

[0169] The injection device 400 as illustrated in Figs. 33-36 is slightly different from the injection device 1 as illustrated in Figs. 1-32. The injection device 400 is also of the pen injector type. It includes a distal end 402 configured for releasable coupling with a needle hub, not illustrated here. It includes a proximal end 403 having a trigger or button 472. The basic functionality of the injection device 400 is comparable to that of the injection device 1. The injection device 400 can be switched between a dose setting mode and a dose ejection mode by depressing the trigger 472 in the distal direction. The injection device 400 includes a cartridge holder 20 configured to accommodate a cartridge 100 filled with a liquid medicament 6.

[0170] In the proximal direction, the cartridge 100 is sealed by a bung 101. The cartridge holder 20 is connectable or connected to a distal end of a body or housing 410 of the injection device 400. The injection device 400 comprises a dose ejection mechanism 4 and a dose setting mechanism 5 for setting and dispensing a dose of the medicament 6. The injection device 400 comprises an elongated piston rod 430 that is threadedly engaged with a radially inwardly projecting flange 412 of the housing 410. The piston rod 430 further comprises a drive shaft or drive sleeve and is in splined engagement with a driver 450 that surrounds the piston rod 430. The driver 430 is snapped into a ratchet sleeve 480. It is axially fixed to the ratchet sleeve 480 and non-rotatably locked to the ratchet sleeve 480. There may be a small amount of rotational play between the driver 450 and the ratchet sleeve 480. The distal end of the piston rod 430 is provided with a rotatable bearing 432 which acts as a pressure piece to exert a distally directed pressure on the bung 101 .

[0171] The ejection mechanism is a wind-up ejection mechanism. It includes a torsion spring 490. One end of the torsion spring 490 is fixed and connected to the ratchet sleeve 480. The opposite end of the torsion spring 490 is connected to a stop member 541. The stop member 541 is fixedly mounted inside the housing 410. The injection device 400 further includes a dose selector 482 rotatable relative to the housing and axially fixed to the housing 410. The button or trigger 472 is biased by a compression spring 474. It is depressable in a distal direction against the action of the spring 474. The button or trigger 472 is axially displaceable relative to the dose selector 482. It is configured to bias the driver 450 in a distal direction. There is a hook connection between the stem 476 of the trigger 470 and a radially inwardly extending protrusion of the driver 450. When button 472 is depressed distally, it abuts axially against the proximal end of driver 450, thus urging driver 450 distally. Under the action of spring 474, button 472 is displaceable proximally and the snap connection to driver 450 pulls driver 450 back to the initial dose setting position, as illustrated, for example, in Figures 33 and 34.

[0172] The housing 410 includes a window 411 for visualizing a portion of the outer circumference of the dose indicator 470. The exterior of the dose indicator 470 is provided with sequential numeric or other dose sizes indicating codes that appear within the window 411 when the dose indicator 470 is subjected to rotation relative to the housing 410. The dose indicator 470 includes a helical thread that is threadedly engaged with a corresponding helically threaded structure on the inner surface of the sidewall of the housing 410. The dose indicator 470 is in splined engagement with a ratchet sleeve 480.

[0173] A spline nut 434 and a locking nut 436 are further provided. The spline nut 434 is in splined engagement with the lead screw 430. Thus, rotation of the spline nut 434 results in rotation of the lead screw 430. The spline nut 434 can slide in an elongated groove (not illustrated) on the lead screw 430. The spline nut 434 is axially constrained inside the housing 410. The locking nut 436 is axially displaceable relative to the housing 410 between a dose setting position and a dose ejection position. In the dose setting position, and thus in the proximal position, the locking nut 436 is non-rotatably locked to the body via the mutually corresponding splined connection. In the distal dose ejection position, the locking nut 436 is non-rotatably locked to the spline nut 434 and is configured to transfer angular momentum to the spline nut 434.

[0174] On the inner circumference of the locking nut 436 is a toothed structure configured to engage a ratchet feature provided on a distal sleeve portion 482 of the ratchet sleeve 480. For dose setting and as the ratchet sleeve 480 is rotated in a dose increment direction, the ratchet feature of the ratchet sleeve 480 generates an audible sound and defines several discrete rotational positions of the ratchet sleeve 480 relative to the housing 410. Each discrete angular position of the ratchet sleeve 480 corresponds to and defines a particular size of a dose of the medicament 6. The ratchet sleeve 480, the driver 450, and the locking nut 436 are displaceable between a proximal dose setting position and a distal dose ejection position. In the dose setting position, the dose selector 482 is non-rotatably locked to the driver 450. To this end, a radially inwardly extending flange portion of the dose selector 482 is in splined engagement with splines on an outer surface of a portion of the driver 450. Thus, rotation of the dose selector 482 rotates the driver 450 and therefore the ratchet sleeve 480. The ratchet feature of the ratchet sleeve 480 clicks over the internal ratchet teeth of the locking nut 436. The locking nut 436 is prevented from rotating by external ribs that engage teeth in the body. The ratchet feature or ratchet arm of the ratchet sleeve prevents the stored energy in the torsion spring 490 from unwinding the selected dose. is powerful enough.

[0175] To dispense a dose, the user presses the button or trigger 472, thus compressing the compression spring 474. The teeth on the driver 450 and the teeth or spline features of the dose selector 482 disengage, and the dose selector 482 is thus non-rotatably decoupled from the driver 450. Distal displacement of the button or trigger 470 results in a respective distal displacement of the driver 450, as the trigger 470 or button axially abuts the proximal end of the driver 450. As the driver 450 advances distally, the locking nut 436 also advances distally together with the ratchet sleeve 480. The locking nut is thus disengaged from the teeth, and the body and locking nut 436 are free to rotate under the action of the depleting torsion spring 490. When in the dose ejection position, the locking nut 436 is non-rotatably coupled to, or non-rotatably locked into, the spline nut 434. Thus, the rotation of the locking nut 436 induced by the ratchet sleeve 480 driven under the action of the torsion spring 490 is transmitted unchanged to the rotation of the spline nut 434, thus rotating the lead screw 430, which advances in the distal direction due to the threaded engagement with the flange 412.

[0176] The injection device 400 may also be equipped with a final dose limiter as well as a final dose limiter, this function not being further illustrated.

[0177] In accordance with the terms of the claims, the ratchet sleeve 480 serves as the rotatable member 460, and the housing 410 provides the mating member 440. As illustrated in FIG. 34, the rotatable member 460 includes a second mechanical cord 462 of a complementary shape to the first mechanical cord 442 of the mating member 440. The first mechanical cord 442 includes a first mechanical cord feature 445, and the second mechanical cord 462 also includes a first feature 465. The first cord feature 465 includes a radial protrusion 466, and the first cord feature 445 includes a radial recess 448. The cord feature 445 further includes multiple protrusions 446, which are separated by recesses smaller than the circumferential width of the protrusions 466.

[0178] Thus, the radial projection 466 of the rotatable member 460 must be aligned longitudinally with the recess 448 of the counter member 440. Only when the mutually corresponding first and second mechanical codes 442, 462 are aligned longitudinally, the rotatable member 460 can be displaced in the distal direction 2 relative to the counter member 440 to the dose ejection position e. The first mechanical code 442 includes an abutment surface 444 facing in the proximal direction, and the second mechanical code 462 includes an abutment surface 466 facing in the distal direction 2 on the radially outwardly extending projection 466. In case of rotational misalignment of the rotatable member 460 and the counter member 440, the distal displacement of the rotatable member 460, and thus of the ratchet sleeve 480, is blocked and prevented. As a result, the injection device 400 cannot be switched from the dose setting mode to the dose ejection mode.

[0179] Although not illustrated, multiple first and second code features may be provided on the outer circumference of the rotatable member 460 as well as the inner circumference of the mating member 440. Depending on the shape and geometric configuration of the first and second mechanical codes 442, 462, various discrete and predetermined allowable dose sizes can be defined. For this, only modification of the first mechanical code 242 of the mating member is required.

[0180] Further examples of rotatable members and mating members are illustrated in Figures 35 and 36. Here, mating member 540 forms or mates with stop member 541 which is securely located inside housing 410. Rotatable member 560 is formed or constituted by driver 450. Counter member 540 is The mating member 540 includes a first mechanical cord 542 of a complementary shape to a second mechanical cord 562 of the rotatable member 560. The first mechanical cord 542 includes at least a first cord feature 545. The first cord feature 545 includes at least one of a protrusion 546 and a recess 548. The protrusion 546 may include a radially inwardly extending flange on the sleeve-shaped portion of the mating member 540. The recess 568 may include or be formed as a recess or an interruption of the radially inwardly extending flange or protrusion 566.

[0181] The second mechanical cord 562 includes at least a first cord feature 565. The first cord feature 565 includes at least one protrusion 566. The protrusion is a radially outwardly extending protrusion 566. The protrusion 566 is located at a predefined angular position on the outer surface of the sleeve of the rotatable member 560, and thus on the driver 450. In the dose setting position as illustrated, the protrusion 566 and the protrusion 546 are separated by an axial distance, or they can approximately abut.

[0182] In the dose setting position, the protrusion 566 of the rotatable member 560 is located proximal to the protrusion 546. In case of misalignment, the protrusions 546, 566 are longitudinally aligned. When the trigger 472, and thus the rotatable member 560, are subjected to a distal displacement towards the ejection position, the distally facing abutment 564 of the protrusion 566 abuts the proximally facing abutment 544 of the protrusion 546. In this manner, further distal displacement of the rotatable member 560 is effectively blocked. It cannot reach the dose ejection position e and switch the injection device 400 to the dose ejection mode.

[0183] This configuration is illustrated in FIG. 36. As a result, and due to the axial abutment of the trigger 472 and the rotatable member 560, the trigger 472 also cannot be depressed in the distal direction 2. Here, the user experiences somewhat direct mechanical and tactile feedback. Because there is minimal axial play between the trigger 472 and the driver 450 or the rotatable member 560, the user can be provided with somewhat robust and immediate blocking with substantially no axial play if the actual dialed dose size does not match the predetermined and required size of the dose.

[0184] In a different configuration illustrated in Fig. 35, the dose selector 482 is dialed to set a dose of a predetermined size. Here, the second mechanical code 562 is longitudinally aligned with the first mechanical code 542. The protrusion 566 is aligned with the correspondingly shaped recess 548, into which the protrusion 566 can slide or pass. Thus, the rotatable member 560 can be displaced to a dose ejection position e, switching the injection device 400 to a dose dispensing mode. [Explanation of symbols]

[0185] 1. Injection device 2 Distal direction 3 Proximal direction 4 Ejection mechanism 5 Dose setting mechanism 6. Drugs 10. Housing 11a,b opening 12 Flange-like inner wall 13. Strip 14 teeth 15 Spline 16 Internal Thread 20 Cartridge holder 30 Lead screw (piston rod) 31 External Thread 32 Clip Arm 33 Concave contact surface 40 Driver (axially movable drive sleeve) 41 teeth 42 Spline 43 ratchet teeth 44 Threaded part 45 Spline 46 Final Dose Stopper 47 Lamp 50 Nut 51 Final Dose Stopper 52 Spline 60 Dose Indicator (Number Sleeve) 60a Number Sleeve Bottom 60b Number sleeve top 61 Spline 62 Flange 63 External Thread 64, 65 End stopper 66 Spline 67 Clicker Arm 68 Groove 69 Anchor Point 70 Button 71 Handle 72 Flange 73, 74 Spline 75 ratchet teeth 80 Dose Selector 90 Torsion Spring 91, 92 Hook 93, 94 Coil 100 cartridges 101 Stopper 110 Gauge Elements 111 Spiral Features 112, 113 Fastener 114 Aperture 115, 116 Flanges 117 Cam 118 Recess 120 Clutch plate 121 ratchet teeth 122 Convex 123 Clicker Arm 130 Clutch spring 140 Bearing part 141 Disc 142 Handle 143 Convex Contact Surface 144 Concave part 240 Counterpart parts 242 Mechanical Code 244 Contact part 245 Code Features 246 Convex 248 Recess 260 Rotatable Member 262 Mechanical Code 264 Contact part 265 Code Features 266 Convex 268 Recess 310 Housing 340 Counterpart parts 342 Mechanical Code 344 Contact part 345 Code Features 346 Convex 348 Recess 360 Rotatable member 362 Mechanical Code 364 Contact part 365 Code Features 366 Convex 368 Recess 370 End face 371 Skirt 372 Ribs 373 Skirt extension 400 Injection Device 402 Distal end 403 Proximal end 410 Housing 411 Window 412 Flange 430 Piston rod 432 Bearing part 434 Spline nut 436 Locking Nut 440 Counterpart 442 Mechanical Code 444 Contact part 445 Code Features 446 Convex 448 Recess 450 Driver 460 Rotatable member 462 Mechanical Code 464 Contact part 465 Code Features 466 Convex 470 Dose Indicator 472 Trigger 474 Compression Spring 476 Handle 480 Ratchet Sleeve 482 Dose Selector 484 Sleeve part 490 Torsion Spring 540 Counterpart 541 Fastener parts 542 Mechanical Code 544 Contact part 545 Code Features 546 Convex 548 Recess 560 Rotatable member 562 Mechanical Code 564 Contact part 565 Code Features 566 Convex

Claims

1. 1. An injection device for the ejection of a medication in several pre-set or user selectable doses, comprising: an elongate housing (310) extending along a longitudinal axis (l) and configured to receive a cartridge (100), the cartridge (100) containing a medicament and having a bung (101) sealing a proximal end of the cartridge (100); an ejection mechanism (4) including a trigger (70) and a piston rod (30), the piston rod (30) being configured, when triggered by the trigger (70), to bias the piston rod (30) against the bung (101) along a longitudinal axis (l) in a distal direction relative to the housing (10); a dose setting mechanism (5) comprising a rotatable member (360) and a counter member (340), the counter member (340) comprising a first mechanical cord (342) and the rotatable member (360) comprising a second mechanical cord (362) of a complementary shape to the first mechanical cord (342); The first mechanical cord (342) includes a first cord feature (345) including at least one of a protrusion (346) and a recess (348), and the second mechanical cord (362) includes another first cord feature (365) including the other of a protrusion (366) and a recess (368) that are complementary in shape to the protrusion (346) and the recess (348) of the first cord feature (345); wherein for dose setting, the rotatable member (360) is rotatable relative to the housing (310) and relative to the counter member (340) within a number of rotational states, and during dose setting, the rotatable member (360) is constrained along a longitudinal axis (l) relative to the housing (310) or relative to the counter member (340); one of the rotatable member (360) and the counter member (340) is displaceable along the longitudinal axis (l) relative to the other of the rotatable member (360) and the counter member (340) to an ejection position (e) only when the first mechanical cord (342) is aligned with the second mechanical cord (362) for ejection of a dose; The injection device, wherein at least one convex portion (346, 366) is an axial convex portion extending along the longitudinal direction (l), and at least one concave portion (348, 368) is an axial concave portion extending along the longitudinal direction (l).

2. 2. The injection device of claim 1, wherein at least one of the axial protrusions (346, 366) and the axial recesses (348, 368) comprises a tapered or toothed structure facing in the longitudinal direction (l).

3. 3. The injection device of claim 1 or 2, wherein longitudinal displacement of one of the rotatable member (360) and the counter member (340) to the ejection position (e) is prevented unless the first mechanical cord (342) and the second mechanical cord (362) are aligned.

4. An injection device according to any one of claims 1 to 3, wherein the first mechanical cord (342) is axially offset from the second mechanical cord (362) when at least one of the rotatable member (360) and the counter member (340) is in a dose setting position.

5. An injection device according to any one of claims 1 to 4, further comprising a dosing spring (130) compressible along a longitudinal direction (l) and engaged with one of the rotatable member (360) and the counter member (340), wherein the rotatable member (360) or the counter member (340) is displaceable along the longitudinal direction (l) from a dose setting position (s) to a dose ejection position (e) against the action of the dosing spring (130).

6. 6. The injection device according to any one of claims 1 to 5, wherein the first mechanical cord (342) comprises a second cord feature (345') comprising at least one of a protrusion (346) and a recess (348), and the second mechanical cord (362) comprises a second cord feature (365') comprising the other of a protrusion (366) and a recess (368) that is complementary in shape to the protrusion (346) or the recess (348) of the second cord feature (345') of the first mechanical cord (342) (342), and the first and second cord features (345) and (345') of at least one of the first mechanical cord (342) and the second mechanical cord (362) are arranged at a predetermined angular distance from each other on a circumference of at least one of the counter member (340) and the rotatable member (360).

7. 7. An injection device according to any one of claims 1 to 6, wherein at least one of the first mechanical cord (342) and the second mechanical cord (352) comprises at least two or more cord features (345, 365) including at least one of a protrusion (346) and a recess (348) that are equidistantly or equiangularly arranged around at least one of the counter member (340) and the rotatable member (360).

8. An injection device according to any one of claims 1 to 7, wherein the counter member (340) and the rotatable member (360) are non-rotatably connectable or non-rotatably lockable to each other via a first mechanical cord (342) and a second mechanical cord (362).

9. 9. The injection device of claim 8, wherein when one of the rotatable member (360) and the counter member (340) reaches the ejection position (e), the counter member (340) and the rotatable member (360) are locked against rotation.

10. An injection device according to any one of claims 1 to 9, wherein the counter member (340) is integrated in or rigidly connected to the housing (10; 310) and the rotatable member (360) is formed by a trigger (70) or is longitudinally displaceable relative to the housing (10; 310) by depressing the trigger (70) in the distal direction.

11. An injection device according to any one of claims 1 to 9, further comprising a dose indicator (60) and a drive sleeve (40), wherein the dose indicator (60) forming the rotatable member (260) is threadedly engaged with the housing (10) and the drive sleeve (40) forming the counter member (240) is longitudinally displaceable relative to the housing (10; 310) by distally depressing a trigger (70).

12. The injection device according to any one of the preceding claims, further comprising a cartridge (100) containing a medicament and disposed inside the housing (10).

13. 13. An injection device according to any one of claims 1 to 12, wherein the trigger (70) is blocked from being fully depressed in the distal direction unless the first mechanical cord (342) and the second mechanical cord (362) are aligned.

14. An injection device according to any one of claims 1 to 13, wherein a first mechanical code (342) is provided on an end face of the counter member (340) and a second mechanical code (362) is provided on an end face of the rotatable member (360) and is directed towards the end face of the counter member (340).

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