Injection device for administering a fluid product and method for assembling said device

Abstract

The invention relates to an injection device for administering a fluid product into the body of a patient and to a method for assembling said injection device. Said injection device comprises an at least two-part plunger rod (2a; 2a'; 2a''; 2b; 2b'; 2b''), wherein the axial distance between said plunger rod (2a; 2a'; 2a''; 2b; 2b'; 2b'') and a stopper (3a; 3a') provided in a container (3; 3') is determined during the assembly of the injection device and is determined in such a way that a distal end of said plunger rod (2a; 2a'; 2a''; 2b; 2b'; 2b'') and the stopper (3a; 3a') rest against each other.

Description

[0001] Injection device for administering a fluid product and method for assembling this device

[0002] The invention relates to an injection device for administering a fluid product, in particular a liquid medicament, from an injection device into the body of a patient and a method for assembling this injection device.

[0003] The term "medicine" as used herein includes any flowable medicinal formulation suitable for controlled administration through a means such as a hypodermic needle, a cannula, or a hollow needle, for example, comprising a liquid, a solution, a gel, or a fine suspension containing one or more medicinally active ingredients. A medicament may be a composition with a single active ingredient or a premixed or co-formulated composition with multiple active ingredients from a single container. Medication includes drugs such as peptides (e.g.Insulins, insulin-containing medicines, GLP-1-containing and derived or analogous preparations), proteins and hormones, biologically derived or active ingredients, active ingredients based on hormones or genes, nutritional formulations, enzymes and other substances in solid (suspended) or liquid form, but also polysaccharides, vaccines, DNA or RNA or oligonucleotides, antibodies or parts of antibodies as well as suitable base, excipient and carrier substances.

[0004] Various administration devices are known from the prior art. Document EP2247327B1 discloses an injection device with a variable connection between the stopper and the piston rod, which comprises a piston rod means and a piston rod base. This variable connection allows the piston rod and the stopper to be assembled or mounted without any gap between them. This is particularly desirable, on the one hand, to compensate for manufacturing tolerances of the individual parts of the injection device and, on the other hand, to allow the user to omit the priming process performed before the administration process. The priming process must be performed before administering a dose so that a correct dose can be administered. This is particularly important for an injection device in which one or more fixed and equal doses are administered.

[0005] A disadvantage of this injection device is that its assembly or mounting is difficult, since the piston rod means and the piston rod base must be welded together, particularly using a complex laser process, to form an injection device with a piston rod that is in abutting contact with the plug. It is an object of the invention to provide an injection device and a method for assembling this injection device, wherein the assembly or mounting of the injection device and the handling of the injection device are simplified for the user.

[0006] This object is achieved by the subject matter of the independent claims. Advantageous embodiments are defined in the dependent claims.

[0007] In the injection device according to the invention, the distal direction refers to the side to which an injection needle can be attached to administer the fluid product. In the injection device according to the invention, the proximal direction refers to the side opposite the distal side.

[0008] The injection device according to the invention for administering a fluid product with a longitudinal axis (L) comprises a housing with a distal and a proximal end. The housing can be at least partially or completely sleeve-shaped.

[0009] The injection device further comprises a container containing the fluid product and a plug axially movable along the longitudinal axis (L). The plug is received in the container and can be moved in the distal direction to discharge the fluid product. The plug can be moved in the distal direction via a piston rod. The piston rod is formed in several parts, in particular at least in two parts. The piston rod can thus also comprise more than two parts. The piston rod is provided at least partially or completely in the housing.

[0010] The at least two-part piston rod comprises a piston rod means and a piston rod base, wherein the piston rod base is at least partially received by the piston rod means. The piston rod base and the piston rod means are axially movable relative to one another and arranged in a rotationally fixed manner relative to one another. The axial distance between the piston rod base and the plug is determined during assembly of the injection device and is determined such that a distal end of the piston rod base and the plug are in contact with one another. The length of the piston rod can be determined or adjusted by the axial relative movement between the piston rod means and the piston rod base.During assembly of the injection device, by bringing the distal end of the piston rod base together with the stopper, in particular with the proximal end of the stopper, it is possible, on the one hand, to compensate for manufacturing tolerances of the individual parts of the injection device and, on the other hand, to omit the priming process performed by the user prior to the administration process. After bringing the distal end of the piston rod base together with the stopper, in particular with the proximal end of the stopper, an injection device is available through which a correct dose can be administered without a prior priming process.

[0011] The injection device comprises an insert. The insert can be at least partially or completely sleeve-shaped. The insert has an external thread. The external thread is preferably arranged on an outer surface of the insert. The insert is provided at a proximal end of the piston rod base and / or within the piston rod base. The external thread of the insert is in threaded engagement with an internal thread on the piston rod means or alternatively with an internal thread on the piston rod base, wherein upon relative rotation between the insert and the piston rod means or alternatively the piston rod base, the piston rod base is axially movable relative to the piston rod means such that the distal end of the piston rod base and the plug abut one another. The insert is arranged rotatably relative to the piston rod means and / or the piston rod base.The piston rod means and / or the piston rod base are preferably connected to the housing in a rotationally fixed manner. The use of the injection device thus ensures that the piston rod base can be moved in the distal direction during assembly or mounting of the injection device, thereby coming into contact with the plug. By using the injection device insert, the joining of the distal end of the piston rod base with the plug, in particular with the proximal end of the plug, can be carried out as simply, cost-effectively, and reliably as possible.

[0012] The piston rod base is at least partially received by the piston rod means. The piston rod base is arranged to be axially movable relative to the piston rod means. Thus, the length of the piston rod can be determined or adjusted. The piston rod means is preferably at least partially or completely sleeve-shaped. The piston rod base can be formed from solid material or, alternatively, at least partially or completely sleeve-shaped. The piston rod base is preferably received in the at least partially or completely sleeve-shaped piston rod means.

[0013] In one embodiment of the invention, a toothing can be provided at the proximal end of the piston rod base and a toothing can be provided at a distal end of the insert, wherein the two toothings are arranged to be rotatable relative to one another in a first direction of rotation about the longitudinal axis (L). The two toothings are designed such that the two toothings are rotatable relative to one another in a first direction of rotation about the longitudinal axis (L). In this embodiment, the insert with the external thread is in threaded engagement with the internal thread of the piston rod means. The insert is provided at the proximal end of the piston rod base. The insert can move or push the piston rod base relative to the piston rod means in the distal direction. The insert is arranged to be axially movable and rotatable relative to the piston rod means.The insert can be rotated relative to the piston rod means in the first rotational direction about the longitudinal axis (L) in order to displace the piston rod base in the distal direction.

[0014] In another embodiment of the invention, a toothing can be provided at the proximal end of the piston rod means and a toothing can be provided at a proximal end of the insert, wherein the two toothings are arranged to be rotatable relative to one another in a first direction of rotation about the longitudinal axis (L). The two toothings are designed such that the two toothings are rotatable relative to one another in a first direction of rotation about the longitudinal axis (L). In this embodiment, the insert with the external thread is in threaded engagement with the internal thread of the piston rod base. The insert is provided within the piston rod base. Preferably, the insert can be designed such that it is provided at least partially within the piston rod base and is also arranged at the proximal end of the piston rod base.The insert can be rotated relative to the piston rod base in the first rotational direction about the longitudinal axis (L) in order to move the piston rod base in the distal direction.

[0015] In addition, the two toothings of the first and the other embodiment of the invention can be designed such that a relative rotation in a second direction of rotation opposite to the first direction of rotation is blocked.

[0016] Due to the threaded engagement between the insert and the piston rod means or alternatively the piston rod base, the rotation in the first direction of rotation about the longitudinal axis (L) causes the piston rod base to be axially movable relative to the piston rod means, in particular in the distal direction, such that the distal end of the piston rod base and the plug lie against one another. The insert is rotated relative to the piston rod means and / or the piston rod base in the first direction of rotation about the longitudinal axis (L). The piston rod base is moved axially relative to the piston rod means, in particular in the distal direction, until the distal end of the piston rod base axially abuts the plug, whereby the distal end of the piston rod base and the plug come to lie against one another.

[0017] During the relative rotation between the insert and the piston rod base or alternatively the piston rod means in the first direction of rotation about the longitudinal axis (L), the rotational force can increase to indicate, upon reaching a certain threshold value, that the distal end of the piston rod base is in axial abutment contact with the plug. Thus, it can be precisely determined when the distal end of the piston rod base and the plug, in particular the proximal end of the plug, are in axial abutment contact. At this threshold value, the toothing between the insert and the piston rod base or alternatively the piston rod means is locked. This locking between the insert and the piston rod base or alternatively the piston rod means has the effect that the piston rod means and the piston rod base are axially fixedly connected relative to one another, in particular via the insert.Thus, the at least two-part piston rod is formed, which can move the plug received in the container in the distal direction in order to pour out the fluid product.

[0018] Relative rotation between the insert and the piston rod means and / or the piston rod base in a second direction of rotation opposite to the first direction of rotation is blocked. For this purpose, the two toothings are designed such that relative rotation in the first direction of rotation about the longitudinal axis (L) is possible and in the second direction of rotation is prevented. Thus, the stop contact between the piston rod base and the plug cannot be released.

[0019] The insert can engage, in particular, rotationally fixed, with a tool of the injection device, and the tool can rotate the insert relative to the piston rod means and / or the piston rod base in the first rotational direction about the longitudinal axis (L). The insert can have an opening, in particular at the proximal end, which serves to allow the tool to engage, in particular, rotationally fixed, with the insert in order to transmit rotation of the tool, in particular rotation of the tool in the first rotational direction about the longitudinal axis (L), to the insert.

[0020] By rotating the insert or the insert connected to the tool, the axial distance between the piston rod base and the plug can be determined such that the distal end of the piston rod base and the plug are aligned. This is a simple, cost-effective, and reliable assembly step for aligning the distal end of the piston rod base with the plug.

[0021] In a single assembly step, the container holder, which houses the container, can be axially connected to the housing, which houses the piston rod base, the piston rod center, and the insert. A snap connection, plastic deformation, a screw connection, an adhesive connection, or a welded connection can be provided.

[0022] In one embodiment of the invention, in a prior assembly step, the insert with an external thread is screwed into the piston rod means with an internal thread, and the piston rod base is inserted into the piston rod means through the distal end of the piston rod means. In another embodiment of the invention, alternatively, in a prior assembly step, the insert with an external thread is screwed into the piston rod base with an internal thread, and the piston rod base accommodated by the insert is inserted into the piston rod means.

[0023] To form a fixed, particularly axially and rotationally fixed, connection between the container holder and the housing, the container holder can have one or more snap elements or snap counter-elements that snap into one or more snap counter-elements provided on the housing. The snap elements and the snap counter-elements can have various designs.

[0024] Alternatively, the container holder or the housing can have one or more plastically deformable elements, in particular one or more plastically deformable ribs, which can engage with one or more corresponding counter-elements on the container holder or on the housing, for example one or more micro-toothings or one or more toothed ribs, in order to form a fixed, in particular axially and rotationally fixed connection between the container holder and the housing. The plastically deformable element and the corresponding counter-element can be provided on an outer or inner surface of the container holder or on an outer or inner surface of the housing, so that the container holder and the housing can be firmly connected, in particular axially and rotationally fixed, by a relative axial movement and / or by a relative rotational movement between the container holder and the housing.The one or more plastically deformable ribs are formed from a plastically deformable material. The one or more corresponding counter-elements are preferably formed from a rigid material or from a material that is not plastically deformable or less deformable than the material of the plastically deformable element.

[0025] Alternatively, the container holder and the housing can be screwed, glued or welded together, for example by laser welding.

[0026] Alternatively, a screw nut can be provided between the container holder and the housing in order to form a fixed, in particular axially and rotationally fixed connection between the container holder and the housing. The screw nut can be self-locking. For example, the container holder and the housing can first be connected to one another via a threaded connection, with the screw nut being arranged between the container holder and the housing. The screw nut can then secure the threaded connection between the container holder and the housing in that, through relative rotation between the screw nut and the container housing or the housing, a toothing provided on the screw nut can engage with a toothing provided on the container holder or on the housing in order to form a fixed, in particular axially and rotationally fixed connection between the container holder and the housing.

[0027] Alternatively, a sleeve can be provided between the container holder and the housing in order to form a fixed, in particular axially and rotationally fixed connection between the container holder and the housing. The sleeve can be designed as a spring element or at least partially resilient or elastic. For example, the container holder and the housing can first be connected to one another via a threaded connection, wherein the sleeve is arranged between the container holder and the housing. The sleeve can then secure the threaded connection between the container holder and the housing in that, through relative rotation between the sleeve and the container housing or the housing, a toothing provided on the sleeve can engage with a toothing provided on the container holder or on the housing in order to form a fixed, in particular axially and rotationally fixed connection between the container holder and the housing.Alternatively, the sleeve can be firmly connected, in particular axially and rotationally fixed, to the container holder or the housing or can be formed in one piece with the container holder or the housing.

[0028] Combinations of the above-mentioned compounds may also be provided.

[0029] The injection device can preferably have a container fixation in order to hold the container in the container holder in the distal direction, in particular without play. The container fixation can be designed as a holding element. The holding element can be designed as a separate element or, alternatively, can be formed integrally with the housing, the container holder or the container of the injection device. The holding element can be at least partially sleeve-shaped, completely sleeve-shaped or made of solid material. The holding element can preferably be at least partially or completely resilient or elastic. In another embodiment of the invention, the holding element can preferably be at least partially or completely plastically deformable.Thus, during assembly of the container holder with the housing, the retaining element can move or push the container received in the container holder in the distal direction relative to the container holder, so that the container can be held in the container holder without play. This allows manufacturing tolerances of the individual components of the injection device to be compensated.

[0030] The holding element can preferably be designed as a holding spring or as a resilient holding element or alternatively as a plastically deformable rib or ribs which can come into abutting contact with the container, in particular with a proximal edge of the container, in order to push the container in the distal direction relative to the container holder.

[0031] Combinations of the aforementioned connections can also be provided. After the container holder and the housing are firmly connected, particularly axially and rotationally, in a further assembly step, the axial distance between the piston rod base and the plug of the injection device is determined such that a distal end of the piston rod base and the plug lie against each other.

[0032] Due to the relative rotation between the insert and the piston rod means or alternatively the piston rod base in the first direction of rotation about the longitudinal axis (L), the piston rod base is axially displaced relative to the piston rod means such that the distal end of the piston rod base and the plug lie against one another. When a certain threshold value is reached, measuring a force increase, in particular a sudden force increase, can indicate that the distal end of the piston rod base and the plug are lying against one another. This threshold detection measures a torque increase, in particular a sudden torque increase, which occurs during the relative rotation in the first direction of rotation about the longitudinal axis (L) due to the engagement between the toothing of the insert and the toothing of the piston rod base or the toothing of the piston rod means.This locking mechanism between the insert and the piston rod base, or alternatively, the piston rod means, ensures that the piston rod means and the piston rod base are axially fixed relative to each other, particularly via the insert. Thus, the at least two-part piston rod is formed, which can move the plug received in the container in the distal direction to discharge the fluid product.

[0033] In another embodiment of the invention, a toothing can alternatively be provided on the outer surface of the insert, which can engage with one or more snaps on the piston rod base or on the piston rod means to form an axially fixed connection between the piston rod means and the piston rod base, wherein the distal end of the piston rod base and the plug abut each other. The snap can be spring-loaded or elastic. The snap can be provided on an inner surface on the piston rod means or on an inner surface on the piston rod base.

[0034] The invention is described below with reference to several figures. The features disclosed herein advantageously further develop the invention, both individually and in combination. They show:

[0035] Figure 1: an exploded view of a first embodiment of the inventive

[0036] Injection device for administering a fluid product. Figure 2a shows a longitudinal sectional view of an assembly step of the injection device according to Figure 1.

[0037] Figure 2b is a longitudinal sectional view of a further assembly step of the injection device according to

[0038] Figure 1.

[0039] Figure 2c is a longitudinal sectional view of a further assembly step of the injection device according to Figure 1.

[0040] Figure 3: an exploded view of a second embodiment of the inventive

[0041] Injection device for administering a fluid product.

[0042] Figure 4a is a longitudinal sectional view of an assembly step of the injection device according to Figure 3.

[0043] Figure 4b is a longitudinal sectional view of a further assembly step of the injection device according to

[0044] Figure 3.

[0045] Figure 4c is a longitudinal sectional view of a further assembly step of the injection device according to Figure 3.

[0046] Figure 5: an exploded view of a third embodiment of the inventive

[0047] Injection device for administering a fluid product.

[0048] Figure 6a is a longitudinal sectional view of an assembly step of the injection device according to Figure 5.

[0049] Figure 6b is a longitudinal sectional view of a further assembly step of the injection device according to Figure 5.

[0050] Figure 6c is a longitudinal sectional view of a further assembly step of the injection device according to Figure 5.

[0051] Figure 1 shows an exploded view of a first embodiment of the injection device according to the invention for administering a fluid product. The injection device serves to administer several fixed and equal doses. The injection device, having a longitudinal axis (L), comprises a housing (1) with a distal and a proximal end. The housing (1) is sleeve-shaped. The housing (1) can preferably have a window (1a) through which, for example, it can be indicated whether a fixed dose has been drawn up or dispensed. The injection device further comprises a piston rod (2a; 2b) which is at least partially provided in the housing (1). The piston rod (2a; 2b) is designed in several parts. The piston rod (2a; 2b) comprises at least two parts. The at least two-part piston rod (2a; 2b) comprises a piston rod means (2a) and a piston rod base (2b).The piston rod (2a; 2b) is at least partially or completely provided in the housing (1). The injection device further comprises a container (3) containing the fluid product and a plug (3a; Fig. 2a) that is axially movable along the longitudinal axis (L). The container (3) can be accommodated in a container holder (5). The container (3) can be held in the container holder (5) in an axially and rotationally fixed manner. Alternatively, the housing (1) and the container holder (5) can be formed as a single piece. The container holder (5) can preferably have a window (5a) through which the container (3), the fluid product, and / or the movable plug (3a) can be seen. The window (5a) can serve, for example, to indicate to the user whether a fluid product is still intact or exhibits cloudiness or discoloration. Alternatively or additionally, the window (5a) can be used to display, for example, the number of doses administered or still available.An external thread (5b) can be provided at the distal end of the container holder (5) for attaching a removable injection needle. The distal end of the injection device can be covered with a removable closure cap (6). The piston rod (2a; 2b) can move the plug (3a) received in the container (3) in the distal direction to dispense the fluid product. A distal end of the piston rod (2a; 2b), in particular the distal end of the piston rod base (2b), can move the plug (3a) in the distal direction to dispense the fluid product. A flange (2c) can be provided at the distal end of the piston rod (2a; 2b), in particular at the distal end of the piston rod base (2b), which can move the plug (3a) in the distal direction to dispense the fluid product. The piston rod base (2b) and the flange (2c) are axially fixed, in particular axially and rotationally fixed.The piston rod base (2b) and the flange (2c) can be formed as one piece, two pieces, or multiple pieces. Alternatively, the piston rod base (2b) can have no flange (2c). The piston rod base (2b) is at least partially received by the piston rod means (2a), wherein the piston rod base (2b) and the piston rod means (2a) are arranged so as to be axially movable relative to one another and rotationally fixed relative to one another. The piston rod base (2b) is preferably made of solid material, and the piston rod means (2a) is preferably sleeve-shaped. Furthermore, the first embodiment of the injection device according to the invention comprises an insert (4) which is provided at a proximal end of the piston rod base (2b), wherein the insert (4) has an external thread (4a) which is in threaded engagement (4a; Figures 2a, 2d) with an internal thread (Figures 2a, 2d) on the piston rod means (2a).The insert (4) is arranged to be axially movable and rotatable relative to the piston rod means (2a). The insert (4) can move or push the piston rod base (2b) in the distal direction relative to the piston rod means (4a). Upon relative rotation between the insert (4) and the piston rod means (2a), the piston rod base (2b) is axially movable relative to the piston rod means (2a) such that the distal end of the piston rod base (2b), in particular the flange (2c) of the piston rod base (2b), and the plug (3a) lie against one another or come into axial abutment contact. The axial distance between the piston rod base (2b), in particular between the flange (2c) of the piston rod base (2b), and the plug (3a) is determined during assembly of the injection device.Furthermore, the proximal end of the piston rod base (2b) can preferably comprise a toothing (Figures 2a, 2h), and the distal end of the insert (4) can preferably have a toothing (4b), wherein the two toothings (Figures 2a, 2h; 4b) are arranged to rotate relative to one another in a first direction of rotation about the longitudinal axis (L). The two toothings (Figures 2a, 2h; 4b) can preferably be designed such that relative rotation in a second direction of rotation opposite to the first direction of rotation is blocked.

[0052] The first embodiment of the injection device according to the invention further comprises a dose button (8) provided at the proximal end of the housing (1). The dose button (8) can be moved axially back and forth relative to the housing (1) to draw up a predetermined dose of the fluid product and dispense it from the container (3). A marking (8b), visible through the window (1a) in the housing (1), indicates to the user whether a dose has been loaded or dispensed. To use the injection device, the user removes the closure cap (6) provided at the distal end of the injection device and places an injection needle onto an external thread (5b) of the injection device provided at the distal end of the container holder (5). The user pulls the dose button (8) in the proximal direction to load a predetermined dose.The dose button (8) is axially movable relative to the housing (1), in particular axially movable and rotationally fixed. The first embodiment of the injection device according to the invention further comprises a feed sleeve (7) with a retaining catch (7a), wherein the feed sleeve (7) is provided at least partially or completely in the housing (1). Furthermore, the feed sleeve (7) is preferably arranged rotationally fixed relative to the housing (1). When loading the specified dose, the feed sleeve (7) is moved in the proximal direction due to an axially fixed connection between the dose button (8) and the feed sleeve (7). The axially fixed connection between the dose button (8) and the feed sleeve (7) can be designed, for example, as a snap connection between a catch (7c) on the feed sleeve (7) and a recess (8a) in the dose button (8).In this first embodiment of the injection device according to the invention, the piston rod means (2a) has a toothing (2e). The retaining catch (7a) of the advance sleeve (7), which can be released with force, interacts with the toothing (2e) of the piston rod means (2a) in such a way that, upon an axial movement of the dose button (8) relative to the housing (1) in the proximal direction, the retaining catch (7a) of the advance sleeve (7) slides over the toothing (2e) of the piston rod means (2a) in the proximal direction. The piston rod means (2a) is held axially fixed relative to the housing (1). For this purpose, the housing (1) has a retaining catch (not visible) which interacts with the toothing (2e) of the piston rod means (2a) in such a way that during the axial movement of the dose button (8) relative to the housing (1) in the proximal direction, the retaining catch (not visible) of the housing (1) holds the piston rod means (2a) axially fixed relative to the housing (1).When dispensing the specified dose, the user presses the dose button (8) in the distal direction. Due to the axially fixed connection between the dose button (8) and the advance sleeve (7), the advance sleeve (7) is moved in the distal direction. The retaining catch (7a) of the advance sleeve (7) interacts with the toothing (2e) of the piston rod means (2a) in such a way that during the axial movement of the dose button (8) relative to the housing (1) in the distal direction, the retaining catch (7a) of the advance sleeve (7) holds the piston rod means (2a) in engagement with the toothing (2e) of the piston rod means (2a), so that the advance sleeve (7) drives the piston rod means (2a) along in the distal direction. The piston rod means (2a) is thereby moved in the distal direction relative to the housing (1).Due to the locking of the two toothings (Figures 2a, 4b; 2h) between the insert (4) and the piston rod base (2b), the piston rod means (2a) and the piston rod base (2b) are axially fixed relative to each other, in particular axially and rotationally fixed. The piston rod means (2a) thus moves the plug (3a) in the distal direction via the piston rod base (2b), in particular via the flange (2c) axially connected to the piston rod base (2b), in order to discharge the fluid product.The retaining catch (not visible) of the housing (1), which can be released using force, interacts with the toothing (2e) of the piston rod means (2a) in such a way that upon axial movement of the dose button (8) relative to the housing (1) in the distal direction, the retaining catch (not visible) of the housing (1) slides over the toothing (2e) of the piston rod means (2a) and engages with the subsequent toothing (2e) of the piston rod means (2a), which is arranged proximal to the preceding toothing (2e) on the piston rod means (2a). The piston rod means (2a) is thereby moved in the distal direction relative to the housing (1) and dispenses the specified dose. The fixed dose is defined by the corresponding axial stop contacts between a distal and a proximal inwardly projecting projection (not visible) on the housing (1) and an outwardly projecting cam (7b) on the feed sleeve (7).To load another preset dose, the user pulls the dose button (8) proximally again. At the end of the last dispensed dose, a stop (7c) provided on the feed sleeve (7) is in contact with a stop shoulder (2f) provided at the proximal end or in a proximal region of the piston rod means (2a). A further preset dose cannot be loaded.

[0053] Figure 2a shows a longitudinal sectional view of a first assembly step of the first embodiment of the injection device according to the invention according to Figure 1.

[0054] In one assembly step, a container holder unit is formed. To form the container holder unit, the closure cap (6) can first be placed on the container holder (5). Alternatively, the closure cap (6) can be placed on the container holder (5) during another assembly step. In a further assembly step, the container (3) pre-filled with the fluid product can be pushed into the container holder (5). The container (3) received with the stopper (3a) is displaced in the distal direction relative to the container holder (5) by a proximal end of the container holder (5). In another embodiment of the injection device according to the invention, a container fixation, for example in the form of a holding element (1c), for holding the container (3) in the distal direction without play, can be inserted into the container holder (5) before the container (3) is inserted into the container holder (5).In this first embodiment of the injection device according to the invention, the holding element (1c) is designed in the form of a plastically deformable rib. In a further assembly step, a drive unit is formed. To form the drive unit, the piston rod means (2a) is first placed into the advance sleeve (7). The piston rod means (2b) is pushed through the proximal end of the advance sleeve (7) and displaced in the distal direction relative to the advance sleeve (7). In a further assembly step, the insert (4) is screwed into the piston rod means (2a) via the threaded connection (2d; 4a) between the internal thread (2d) of the piston rod means (2a) and the external thread (4a) of the insert (4). The insert (4) is screwed through the proximal end of the piston rod means (2a) in the distal direction into the piston rod means (2b).In a further assembly step, the dose button (8) is placed onto the proximal end of the feed sleeve (7) received with the piston rod means (2a) and moved in the distal direction relative to the feed sleeve (7). In a further assembly step, the assembly consisting of the dose button (8), the feed sleeve (7), the insert (4) and the piston rod means (2a) is placed into the housing (1). This assembly is pushed through the proximal end of the housing (1) and moved in the distal direction relative to the housing (1). In a further assembly step, the piston rod base (2b) is placed into the piston rod means (2a). The piston rod base (2b) is pushed through the distal end of the piston rod means (2b) and moved in the proximal direction relative to the piston rod means (2b).In another embodiment of the device according to the invention, the flange (2c) is axially fixed to the piston rod base (2b) before the piston rod base (2b) is inserted into the piston rod means (2). In a further embodiment of the injection device according to the invention, the flange (2c) is axially fixed to the piston rod base (2b) after the piston rod base (2b) is inserted into the piston rod means (2). In this first embodiment of the device according to the invention, the flange (2c) is formed integrally with the piston rod base (2b).

[0055] In a further assembly step, the container holder unit and the drive unit are joined together, as shown in Figure 2b. In this assembly step, the container holder (5), which houses the container (3), is axially fixedly connected to the housing (1), which houses the piston rod base (2b), the piston rod means (2a), and the insert (4). A snap connection, plastic deformation, a screw connection, an adhesive connection, or a welded connection can be provided.

[0056] In this first embodiment of the device according to the invention, a connecting element (5c) is provided on the container holder (5), which can be connected to a connecting element (1b) of the housing (1). The connecting element (5c) of the container holder (5) or the connecting element (1b) of the housing (1) can have one or more plastically deformable elements, in particular one or more plastically deformable ribs, which can engage with one or more corresponding counter-elements on the connecting element (1b) of the container holder (5) or on the connecting element (1b) of the housing (1), for example one or more micro-toothings or one or more toothed ribs, in order to form a fixed, in particular axially and rotationally fixed, connection.

[0057] The one or more plastically deformable ribs may be formed from a plastically deformable material. The one or more corresponding counter-elements may preferably be formed from a rigid material or from a material that is not plastically deformable or from a material that is less deformable than the material of the plastically deformable element.

[0058] When the container holder unit is assembled with the drive unit, the holding element (1c) comes into abutting contact with the proximal edge (3b) of the container (3). This forces the container (3) in the distal direction relative to the container holder (5) to hold the container (3) in the container holder (5) without play.

[0059] In a further assembly step, as shown in Figure 2c, the axial distance between the piston rod base (2b), in particular the axial distance between the flange (2c) axially fixed to the piston rod base (2b) and the plug (3a) of the injection device is determined such that the distal end of the piston rod base (2b), in particular the flange (2c) axially fixed to the piston rod base (2b) and the plug (3a) come to rest against each other.

[0060] A tool (9) is pushed into the insert (4) through an opening (8c) at the proximal end of the dose button (8). The insert (4) has, in particular, an opening at the proximal end. The tool (9) engages, in particular engages, with the insert (4) in a rotationally fixed manner. The tool (9) rotates the insert (4) relative to the piston rod means (2a) in the first rotational direction about the longitudinal axis (L) due to the threaded connection (4a; 2d) between the insert (4) and the piston rod means (2a). The rotation of the tool (9) in the first rotational direction about the longitudinal axis (L) is transmitted to the insert (4).

[0061] By rotating the insert (4) or the insert (4) connected to the tool (9), the axial distance between the piston rod base (2b), in particular the axial distance between the flange (2c) axially fixed to the piston rod base (2b), and the plug (3a), can be determined such that the distal end of the piston rod base (2b), in particular the flange (2c) axially fixed to the piston rod base (2b), and the plug come to rest against one another. The piston rod base (2b) is moved or displaced in the distal direction within the piston rod means (2a) by the combined axial and rotational movement of the insert (4) and a stop contact between the insert (4) and the piston rod base (2b) relative to the piston rod means (2a).The piston rod means (2a) is held axially fixed relative to the housing (1) due to the engagement between the retaining catch (7a) of the feed sleeve (7) and the toothing (2h) of the piston rod means (2a), and due to the engagement between the retaining catch (not visible) of the housing (1) and the toothing (2h) of the piston rod means (2a). During the relative rotation between the insert (4) and the piston rod means (2a) in the first direction of rotation about the longitudinal axis (L), the rotational force increases to indicate, upon reaching a certain threshold value, that the distal end of the piston rod base (2b), in particular the flange (2c) axially fixedly connected to the piston rod base (2b), is in axial abutment contact with the plug (3a).A torque increase, in particular a sudden torque increase, which can be detected, indicates that the distal end of the piston rod base (2b), in particular the flange (2c) axially fixed to the piston rod base (2b), is in axial abutment contact with the plug (3a). Thus, it can be precisely determined when the distal end of the piston rod base (2b), in particular the flange (2c) axially fixed to the piston rod base (2b), and the plug (3a) are in axial abutment contact. At this threshold value, the toothing (4b; 2h) between the insert (4) and the piston rod base (2b) is locked. This locking between the insert (4) and the piston rod base (2b) causes the piston rod means (2a) and the piston rod base (2b) to be axially fixed relative to one another, in particular via the insert (4).Thus, the at least two-part piston rod (2a; 2b) is formed, which can move the plug (3a) received in the container (3) in the distal direction in order to pour out the fluid product.

[0062] In a further assembly step, the opening (8c) at the proximal end of the dose button (8) can be closed, for example, with a label or a dose cap (11), as shown, for example, in the third embodiment of the injection device according to the invention in Figure 5.

[0063] Figure 3 shows an exploded view of a second embodiment of the injection device according to the invention for administering a fluid product. The first and second embodiments of the injection device according to the invention differ from each other in the arrangement of the insert (3') and the resulting adaptations to the design of the piston rod means (2a') and the piston rod base (2b'). Furthermore, the container fixation has a different design.

[0064] The second embodiment of the injection device comprises an insert (4') provided within the piston rod base (2b'), wherein the insert (4') has an external thread (4a') which is in threaded engagement (4a'; Figures 4a, 2g) with an internal thread (Figures 4a, 2g) on ​​the piston rod base (2b'). The insert (4') is arranged to be axially movable and rotatable relative to the piston rod base (2b'). Upon relative rotation between the insert (4') and the piston rod base (2b'), the piston rod base (2b') is axially movable relative to the piston rod means (4a'), so that the distal end of the piston rod base (2b'), in particular the flange of the piston rod base (2b'), and the plug lie against one another or come into axial abutment contact. The axial distance between the piston rod base (2b'), in particular between the flange of the piston rod base (2b') and the plug is determined during assembly of the injection device.The insert (4') can be rotated relative to the piston rod base (2b') in the first rotational direction about the longitudinal axis (L) in order to displace the piston rod base (2b') relative to the piston rod means (4a') in the distal direction. Furthermore, the proximal end of the piston rod means (2a') can preferably comprise a toothing (2h'), and the proximal end of the insert (4') can preferably have a toothing (4b'), wherein the two toothings (4b'; Figures 4a, 2h') are arranged to be rotatable relative to one another in a first rotational direction about the longitudinal axis (L). The two toothings (4b'; Figures 4a, 2h') can preferably be designed such that a second rotational direction opposite to the first rotational direction is blocked.

[0065] Figure 4a shows a longitudinal sectional view of a first assembly step of the second embodiment of the injection device according to the invention according to Figure 3.

[0066] The assembly steps of the first and second embodiments of the injection device according to the invention differ from each other by individual assembly steps which result from the different arrangement of the insert (4') in the injection device.

[0067] In an assembly step, a container holder unit is formed. Like the container holder unit according to the first embodiment of the injection device according to the invention, the container holder unit comprises the closure cap and the container held by the stopper, with the container being inserted into the container holder.

[0068] In a further assembly step, a drive unit is formed. The formation of the drive unit according to the second embodiment of the injection device according to the invention differs from the assembly steps of the drive unit according to the first embodiment of the injection device according to the invention in that the insert (4') with the external thread (4a') is screwed into an internal thread (2g) of the piston rod base (2b') instead of into an internal thread (2d) of the piston rod means (2a).

[0069] In a first assembly step, the piston rod assembly is first pushed distally into a push sleeve. The dose button is then pushed distally over the push sleeve. The assembly, consisting of the dose button, the push sleeve, and the piston rod assembly, is then pushed distally into the housing.

[0070] The piston rod base (2b') held by the insert (4') is inserted into the piston rod means (2a') in a further assembly step. The piston rod base (2b') held by the insert (4') is pushed through the distal end of the piston rod means (2b) and displaced axially in the proximal direction relative to the piston rod means (2b').

[0071] In a further assembly step, the container holder unit and the drive unit are joined together, as shown in Figure 4b.

[0072] In this assembly step, the container holder, which houses the container, is axially connected to the housing, which houses the piston rod base (2b'), the piston rod means (2a'), and the insert (4'). A snap connection, plastic deformation, a screw connection, an adhesive connection, or a welded connection can be provided.

[0073] In this second embodiment of the device according to the invention, a retaining element (1c') in the form of a retaining spring is provided on the housing. The retaining spring is firmly connected to the housing, particularly axially and rotationally fixed, particularly preferably as a single piece. When the container holder unit is assembled with the drive unit, the retaining element (1c') comes into abutting contact with a proximal edge (3b') of the container in order to press the container in the distal direction relative to the container holder without play.

[0074] In a further assembly step, as shown in Figure 4c, the axial distance between the piston rod base (2b'), in particular the axial distance between the flange axially fixedly connected to the piston rod base (2b') and the plug of the injection device is determined such that a distal end of the piston rod base (2b'), in particular the flange axially fixedly connected to the piston rod base (2b') and the plug come to rest against each other.

[0075] A tool is pushed through the opening at the proximal end of the dose button into the insert (4'). The tool engages, in particular, engages, with the insert (4') in a rotationally fixed manner. The tool of the injection device rotates the insert (4') relative to the piston rod base (2b') in the first rotational direction about the longitudinal axis (L) due to the threaded connection (4a'; 2g) between the insert (4') and the piston rod base (2b'). The rotation of the tool in the first rotational direction about the longitudinal axis (L) is transmitted to the insert (4'). The tool further serves to ensure that the toothing (4b') of the insert (4') can be held in engagement with the toothing (2h') of the piston rod means (2a'), so that when the tool is rotated in the first direction of rotation about the longitudinal axis (L), the insert (4') can be moved axially by the height of the toothing relative to the piston rod means (2a') and / or relative to the housing.By this rotation in the first direction of rotation about the longitudinal axis (L) of the insert (4) or of the insert (4) connected to the tool, the axial distance between the piston rod base (2b'), in particular between the flange axially fixed to the piston rod base (2b'), and the plug (3a), can be determined such that the distal end of the piston rod base (2b'), in particular the flange axially fixed to the piston rod base (2b'), and the plug come to rest against one another. The piston rod base (2b') is moved or displaced in the distal direction within the piston rod means (2a') due to the rotational movement of the insert (4), the threaded engagement (4a'; 2g) between the piston rod base (2b') and the piston rod means (2a'), and the axially fixed connection between the insert (4') and the piston rod means (2a').During the relative rotation between the insert (4') and the piston rod base (2b') in the first direction of rotation about the longitudinal axis (L), the rotational force increases to indicate, upon reaching a certain threshold value, that the distal end of the piston rod base (2b'), in particular the flange axially fixed to the piston rod base (2b'), is in axial abutment contact with the plug (3a). A torque increase, in particular a sudden torque increase, which can be detected, indicates that the distal end of the piston rod base (2b'), in particular the flange axially fixed to the piston rod base (2b'), is in axial abutment contact with the plug. Thus, it can be precisely determined when the distal end of the piston rod base (2b'), in particular the flange axially fixed to the piston rod base (2b'), and the plug (3a) are in axial abutment contact.At this threshold value, the toothing (4b'; 2h') between the insert (4') and the piston rod base (2b') is locked. This locking between the insert (4') and the piston rod base (2b') causes the piston rod means (2a') and the piston rod base (2b') to be axially fixed relative to one another, in particular via the insert (4'). Thus, the at least two-part piston rod (2a'; 2b') is formed, which can move the plug received in the container in the distal direction in order to discharge the fluid product.

[0076] Figure 5 shows an exploded view of a third embodiment of the injection device according to the invention for administering a fluid product. The first and third embodiments of the injection device according to the invention differ from each other in the function of the injection device, namely the function of loading and dispensing a predetermined dose. Furthermore, the container fixation has a different design.

[0077] The third embodiment of the injection device according to the invention with a longitudinal axis (L) comprises a housing (1') with a distal and a proximal end. The housing (1') has a retaining element (1c") in the form of a retaining spring for moving or pushing a container (3') received in a container holder (5') in the distal direction relative to the container holder (5') without play. Furthermore, the third embodiment of the injection device according to the invention comprises a rotating sleeve (10), a feed sleeve (7'), and a dose button (8'). The housing (1') has an internal thread (1d) which is in a first threaded engagement (1d; 10a) with an external thread (10a) of the rotating sleeve (10). In addition, the rotating sleeve (10) comprises an internal thread (Figures 6a; 10b), which is in a second threaded engagement (Figures 6a, 10b; 7d) with an external thread (7d) provided on the feed sleeve (7').The first (1d; 10a) and the second thread engagement (Figures 6a, 10b; 7d) preferably have the same pitch direction. The first thread engagement (1d; 10a) also preferably has a larger thread pitch than the second thread engagement (Figures 6a, 10b; 7d). The second thread engagement (Figures 6a, 10b; 7d) preferably has a smaller thread pitch than the first thread engagement (1d; 10a). This makes it possible to achieve a transmission, in particular a path and / or force transmission, of a loading process and / or a dispensing process of a specified dose. Furthermore, the injection device comprises an at least two-part piston rod (2a"; 2b") for moving a plug (Figures 6a, 3a') received in the container (3') in the distal direction, so that the fluid product is dispensed. The at least two-part piston rod (2a”; 2b”) comprises a piston rod means (2a”) and a piston rod base (2b”).The piston rod base (2b") is at least partially received by the piston rod means (2a"), wherein the piston rod base (2b) and the piston rod means (2a) are arranged axially movable relative to one another and rotationally fixed relative to one another. The injection device further comprises an insert (4") provided at a proximal end of the piston rod base (2b"). The insert (4”) has an external thread (4a”) which is in threaded engagement (4a”; Figure 6a, 2d”) with an internal thread (Figure 6a, 2d') on the piston rod means (2a”). Upon relative rotation between the insert (4”) and the piston rod means (2a”), the piston rod base (2b”) is axially movable relative to the piston rod means (2a”), so that the distal end of the piston rod base (2b”), in particular an axially fixed flange (2c') of the piston rod base (2b”) and the plug (Figure 6a, 3a') lie against one another or come into axial abutment contact.The axial distance between the piston rod base (2b”), in particular between the flange (2c') of the piston rod base (2b”) and the plug (Figure 6a, 3a'), is determined during assembly of the injection device. Furthermore, the proximal end of the piston rod base (2b”) can preferably comprise a toothing (Figure 6a, 2h”), and the distal end of the insert (4”) can preferably have a toothing (4b”), wherein the two toothings (Figure 6a, 2h”; 4b”) are arranged to be rotatable relative to one another in a first direction of rotation about the longitudinal axis (L). The two toothings (Figure 6a, 2h”; 4b”) can preferably be designed such that relative rotation in a second direction of rotation opposite to the first direction of rotation is blocked.

[0078] The third embodiment of the injection device according to the invention further comprises a dose cap (11) arranged at the proximal end of the dose button (8'). The dose cap (11) is preferably axially fixed, in particular axially and rotationally fixed, to the dose button (8'). Alternatively, the dose cap (11) and the dose button (8') can be formed as a single piece. The dose button (8') is arranged at the proximal end of the housing (1') and can be moved axially back and forth relative to the housing (1') to draw up a predetermined dose of the fluid product and dispense it from the container (3'). To use the injection device, the user pulls the dose button (8') in the proximal direction to load a predetermined dose. The dose button (8') is arranged axially movable and rotationally fixed relative to the housing (1'). The rotary sleeve (10) is arranged to be rotatable and axially movable relative to the housing (1').The dose cap (11) comprises a retaining cam (11 a) which engages with a rotary sleeve.

[0079] (10) provided annular groove (Figures 6a, 10c) in order to form an axially fixed and rotatable connection between the rotating sleeve (10) and the dose cap (11) and / or the dose button (8'). Alternatively, an axially fixed and rotatable connection can be provided between the dose button (8') and the rotating sleeve (10) in order to form an axially fixed and rotatable connection between the rotating sleeve (10) and the dose cap (11) and / or the dose button (8'). When loading the specified dose, due to the axially fixed connection between the rotating sleeve (10) and the dose cap (11) and / or the dose button, the rotating sleeve (10) is moved together with the dose button (8') by the same distance in the proximal direction.Due to the first threaded engagement (10a; 10d) between the rotating sleeve (10) and the housing (1'), the rotating sleeve (10) is moved helically in the proximal direction when the specified dose is loaded, wherein the feed sleeve (7') is displaced in the proximal direction by a shorter distance than the rotating sleeve (10) or the dose button (8') due to the second threaded engagement (7d; Figures 6a, 10b) between the feed sleeve (7') and the rotating sleeve (10') and the arrangement which is non-rotatable relative to the housing (1'). The feed sleeve (7') has a retaining catch (7a') which can interact with a toothing (2e') provided on the piston rod means (2a').The retaining snap (7a') of the feed sleeve (7'), which can be released with the application of force, interacts with the toothing (2e') of the piston rod means (2a") in such a way that, upon an axial movement of the dose button (8') relative to the housing (1') in the proximal direction, the retaining snap (7a') of the feed sleeve (7') slides over the toothing (2e') of the piston rod means (2a") in the proximal direction. The piston rod means (2a”) is held axially fixed relative to the housing (1'). For this purpose, the housing (1') has a retaining catch (not visible) which interacts with the toothing (2e') of the piston rod means (2a") in such a way that during the axial movement of the dose button (8') relative to the housing (1') in the proximal direction, the retaining catch (not visible) of the housing (1') holds the piston rod means (2a") axially fixed relative to the housing (1'). When dispensing the specified dose, the user presses the dose button (8') in the distal direction.Due to the axially fixed connection between the rotating sleeve (10) and the dose cap.

[0080] (11) and / or the dose button (8'), the rotation sleeve (10) and the dose button (8') are moved by the same distance in the distal direction, wherein the feed sleeve (7') is displaced by a shorter distance than the rotation sleeve (10) or the dose button (8') in the distal direction due to the second threaded engagement (7d; Figures 6a, 10b) between the feed sleeve (7') and the rotation sleeve (10') and the rotationally fixed arrangement relative to the housing (1'). The retaining catch (7a') of the feed sleeve (7') interacts with the toothing (2e') of the piston rod means (2a") in such a way that during the axial movement of the dose button (8') relative to the housing (1') in the distal direction, the retaining catch (7a') of the feed sleeve (7') holds the piston rod means (2a") in engagement with the toothing (2e') of the piston rod means (2a"), so that the feed sleeve (7') carries the piston rod means (2a") in the distal direction.The piston rod means (2a") is moved in the distal direction. Due to the locking of the two toothings between the insert (4") and the piston rod base (2b'), the piston rod means (2a") and the piston rod base (2b") are axially fixed relative to one another, in particular axially and rotationally fixed. The piston rod means (2a") thus moves the plug (3a') in the distal direction via the piston rod base (2b"), in particular via the flange (2c') connected to the piston rod base (2b"), in order to discharge the fluid product.The retaining catch (not visible) of the housing (1'), which can be released using force, interacts with the toothing (2e') of the piston rod means (2a") in such a way that upon axial movement of the dose button (8') relative to the housing (1') in the distal direction, the retaining catch (not visible) of the housing (1') slides over the toothing (2e) of the piston rod means (2a") and engages in the subsequent toothing (2e') of the piston rod means (2a"), which is arranged proximal to the preceding toothing (2e') on the piston rod means (2a). The piston rod means (2a") is thereby moved in the distal direction and dispenses the specified dose. The fixed dose is defined by the corresponding axial stop contacts and / or rotational stop contacts between a distal and a proximal inwardly projecting projection (not visible) on the housing (1') and an outwardly projecting cam (8d) on the dose button (8').To load a new preset dose, the user pulls the dose button (8') again in the proximal direction. At the end of the last dispensed dose, a stop (not visible) provided on the feed sleeve (7') is in axial stop contact and / or in rotational stop contact with a stop shoulder (2f) provided at the proximal end or in a proximal region of the piston rod means (2a). A further preset dose cannot be loaded.

[0081] Figure 6a shows a longitudinal sectional view of a first assembly step of the third embodiment of the injection device according to the invention according to Figure 5.

[0082] The assembly steps of the first and third embodiments of the injection device according to the invention differ from each other by individual assembly steps which result from the function of loading and dispensing a fixed dose.

[0083] In one assembly step, a container holder unit is formed. The container holder unit is assembled according to the assembly steps of the first embodiment of the injection device according to the invention and, like this container holder unit, comprises a closure cap (6') and the container (3') received by the stopper (3a'), wherein the container (3') is inserted into the container holder (5'). In a further assembly step, a drive unit is formed. To form the drive unit, first the piston rod means (2a') is placed into the advance sleeve (7'). The piston rod means (2b') is pushed through the proximal end of the advance sleeve (7') and displaced in the distal direction relative to the advance sleeve (7').In a further assembly step, the insert (4”) is screwed into the piston rod means (2a”) via the threaded connection (2d'; 4a”) between the internal thread (2d') of the piston rod means (2a”) and the external thread (4a”) of the insert (4”). The insert (4”) is screwed into the piston rod means (2b”) through the proximal end of the piston rod means (2a”) in the distal direction. In a further assembly step, the rotation sleeve (10) is placed onto the proximal end of the feed sleeve (7') received with the piston rod means (2a”) and screwed in the distal direction relative to the feed sleeve (7') with the aid of the second threaded connection (7d; 10b) between the feed sleeve (7') and the rotation sleeve (10). In a further assembly step, the dose button (8) is placed on the proximal end of the feed sleeve (7) received with the piston rod means (2a) and moved in the distal direction relative to the feed sleeve (7).In a further assembly step, the assembly comprising the rotation sleeve (10), the feed sleeve (7'), the insert (4"), and the piston rod means (2a") is placed into the housing (1'). This assembly is placed onto the proximal end of the housing (1') and screwed in the distal direction relative to the housing (1') using the first threaded connection (1d; 10a) between the housing (1') and the rotation sleeve (10). In a further assembly step, the dose cap (11) is connected to the dose button (8') in an axially fixed, in particular axially and rotationally fixed, manner. The assembly comprising the dose cap (11) and the dose button (8') is placed into the housing (1') in a further assembly step. This assembly is placed onto the proximal end of the housing (1').This assembly is displaced axially relative to the housing (1') in the distal direction by the proximal end of the housing (1') in order to form an axially fixed connection between the dose cap (11) and the rotating sleeve (10). In a further assembly step, the piston rod base (2b") is placed into the piston rod means (2a"). The piston rod base (2b") is pushed through the distal end of the piston rod means (2b) and displaced relative to the piston rod means (2b) in the proximal direction, wherein the flange (2c') is provided at the distal end of the piston rod base (2b").

[0084] In a further assembly step, the container holder unit is joined to the drive unit, as can be seen in Figure 6b. In this assembly step, the container holder (5') accommodated with the container (3') is axially fixedly connected to the housing (1') which accommodates the piston rod base (2b"), the piston rod means (2a") and the insert (4"). A snap connection, a plastic deformation, a screw connection, an adhesive connection or a welded connection can be provided. The holding element (1c") provided on the housing (1'), in particular the retaining spring, comes into abutting contact with a proximal edge (3b") of the container (3') when the container holder unit is joined to the drive unit in order to press the container (3') relative to the container holder (5') in the distal direction without play.

[0085] In a further assembly step, as shown in Figure 6c, the axial distance between the piston rod base (2b”), in particular the axial distance between the flange (2c') axially fixed to the piston rod base (2b”) and the plug (3a') of the injection device is determined such that a distal end of the piston rod base (2b”), in particular the flange (2c') axially fixed to the piston rod base (2b”) and the plug (3a') come to rest against each other.

[0086] A tool (9') is pushed through an opening (11b) at the proximal end of the dose cap (11) into the insert (4"). The insert (4) in particular has an opening at the proximal end. The tool (9') engages, in particular in a rotationally fixed engagement with the insert (4"). The tool (9') rotates the insert (4") relative to the piston rod means (2a") due to the threaded connection (4a"; 2d') between the insert (4") and the piston rod means (2a") in the first rotational direction about the longitudinal axis (L). The rotation of the tool (9') in the first rotational direction about the longitudinal axis (L) is transmitted to the insert (4").

[0087] By rotating the insert (4”) or the insert (4”) connected to the tool (9'), the axial distance between the piston rod base (2b”), in particular between the flange (2c') axially fixed to the piston rod base (2b”), and the plug (3a'), can be determined such that the distal end of the piston rod base (2b”), in particular the flange (2c') axially fixed to the piston rod base (2b”), and the plug (3a'), come to rest against one another. The piston rod base (2b”) is moved or displaced in the distal direction within the piston rod means (2a”) by the combined axial and rotational movement of the insert (4”) and a stop contact between the insert (4”) and the piston rod base (2b”) relative to the piston rod means (2a”).During the relative rotation between the insert (4") and the piston rod means (2a") in the first direction of rotation about the longitudinal axis (L), the rotational force increases to indicate, upon reaching a certain threshold value, that the distal end of the piston rod base (2b"), in particular the flange (2c') axially fixed to the piston rod base (2b"), is in axial abutment contact with the plug (3a'). A torque increase, in particular a sudden torque increase, which can be detected, indicates that the distal end of the piston rod base (2b"), in particular the flange (2c') axially fixed to the piston rod base (2b"), is in axial abutment contact with the plug (3a'). Thus, it can be determined exactly when the distal end of the piston rod base (2b”), in particular the flange (2c') axially fixed to the piston rod base (2b”) and the plug (3a') are in axial stop contact.At this threshold value, the toothing (4b”; 2h”) between the insert (4”) and the piston rod base (2b”) is locked. This locking between the insert (4”) and the piston rod base (2b”) causes the piston rod means (2a”) and the piston rod base (2b”) to be axially fixed relative to one another, in particular via the insert (4”). Thus, the at least two-part piston rod (2a”; 2b”) is formed, which can move the plug (3a') received in the container (3') in the distal direction in order to discharge the fluid product.

[0088] In a further assembly step, the opening (11b) at the proximal end of the dose cap (11) can be closed, for example, with a label or another cap.

[0089] In a further embodiment of the injection device according to the invention, the injection device according to the third embodiment can have an insert according to the second embodiment. The function of this further embodiment of the injection device according to the invention, namely the loading and dispensing of a fixed dose, thus corresponds to the function of the third embodiment of the injection device according to the invention. However, the arrangement and design of the insert according to the further embodiment of the injection device according to the invention correspond to the arrangement and design of the insert according to the second embodiment of the injection device according to the invention.

[0090] Reference symbol:

[0091] 1; 1' housing

[0092] 1 a Window of the housing

[0093] 1 b Connecting element of the housing

[0094] 1c; 1c'; 1c” holding element

[0095] 1d Internal thread of the housing

[0096] 2a; 2a'; 2a” piston rod center

[0097] 2b; 2b'; 2b” piston rod base

[0098] 2c; 2c' flange

[0099] 2d; 2d' internal thread of the piston rod center

[0100] 2e; 2e' toothing of the piston rod means

[0101] 2f; 2f stop shoulder

[0102] 2g internal thread of the piston rod base

[0103] 2h; 2h” toothing of the piston rod base

[0104] 2h' toothing of the piston rod center

[0105] 3; 3' containers

[0106] 3a; 3a' plug

[0107] 3b; 3b'; 3b” proximal edge of the container 4; 4'; 4” insert

[0108] 4a; 4a';4a” external thread of the insert

[0109] 4b; 4b'; 4b” toothing of the insert

[0110] 5; 5' container holder

[0111] 5a Container holder window

[0112] 5b External thread of the container holder

[0113] 5c Connecting element of the container holder

[0114] 6; 6' cap

[0115] 7; 7' feed sleeve

[0116] 7a; 7a' retaining catch

[0117] 7b Cam of the feed sleeve

[0118] 7c stop

[0119] 7d External thread of the feed sleeve

[0120] 8 Dose button

[0121] 8a recess

[0122] 8b Marking

[0123] 8c Opening the dose button

[0124] 8d Dose button cam

[0125] 9; 9' tool

[0126] 10 rotation sleeve

[0127] 10a External thread of the rotating sleeve

[0128] 10b Internal thread of the rotating sleeve

[0129] 10c ring groove

[0130] 11 Dose cap

[0131] 11a Retaining cam

[0132] 11 b Opening of the dose cap

Claims

Patent claims 1 . Injection device for administering a fluid product having a longitudinal axis (L) comprising: -a housing (1; 1') with a distal and a proximal end, -a container (3; 3') containing the fluid product and a plug (3a; 3a') axially movable along the longitudinal axis (L), - a piston rod (2a; 2a'; 2a”) comprising at least two parts, which is provided at least partially or completely in the housing (1; 1') and which can move the plug (3a; 3a') received in the container (3; 3') in the distal direction in order to discharge the fluid product, -wherein the at least two-part piston rod (2a; 2a'; 2a"; 2b; 2b'; 2b") comprises a piston rod means (2a; 2a'; 2a") and a piston rod base (2b; 2b'; 2b") and the piston rod base (2b; 2b'; 2b") is at least partially received by the piston rod means (2a; 2a'; 2a"), -wherein furthermore the piston rod base (2b; 2b'; 2b") and the piston rod means (2b; 2b'; 2b") are arranged axially movable relative to each other and rotationally fixed relative to each other and the axial distance between the piston rod base (2b; 2b'; 2b") and the plug (3a; 3a') is determined during assembly of the injection device and is determined such that a distal end of the piston rod base (2b; 2b'; 2b") and the plug (3a; 3a') lie against each other, characterized in that -an insert (4; 4'; 4") is provided at a proximal end of the piston rod base (2b; 2b'; 2b") and / or within the piston rod base (2b; 2b'; 2b"), wherein the insert (4; 4'; 4") has an external thread (4a; 4a'; 4a") which is in threaded engagement (4a; 4a'; 4a"; 2h; 2h'; 2g) with an internal thread (2h; 2h') on the piston rod means (2a; 2a'; 2a") or with an internal thread (2g) on ​​the piston rod base (2b; 2b'; 2b") and, -wherein upon relative rotation between the insert (4; 4'; 4") and the piston rod means (4a; 4a'; 4a") or the piston rod base (2b; 2b'; 2b"), the piston rod base (2b; 2b'; 2b") is axially movable relative to the piston rod means (2a; 2a'; 2a"), so that the distal end of the piston rod base (2b; 2b'; 2b") and the plug (3a; 3a') lie against one another.

2. Injection device according to claim 1, characterized in that a toothing (2h; 2h”) is provided on the proximal end of the piston rod base (2b; 2b”) and a toothing (4b; 4b”) is provided on a distal end of the insert (4; 4”), wherein the two toothings (2h; 2h”; 4b; 4b”) are arranged to be rotatable relative to one another in a first direction of rotation about the longitudinal axis (L).

3. Injection device according to claim 1, characterized in that at the proximal end of the piston rod means (4a') a toothing (2h') and at a proximal end of the insert (4') a toothing (4b') is provided, wherein the two toothings (2h'; 4b') are arranged to be rotatable relative to one another in a first direction of rotation about the longitudinal axis (L).

4. Injection device according to claim 2 or 3, characterized in that the two toothings (2h; 2h' 2h"; 4b; 4b'; 4b") are designed such that a relative rotation in a second direction of rotation opposite to the first direction of rotation is blocked.

5. A method for assembling a device according to any one of claims 1 to 4, comprising the following steps: -relative rotation of the insert (4; 4'; 4”) to the piston rod means (2a; 2a'; 2a”) or to the piston rod base (2b; 2b'; 2b”) in a first direction of rotation -relative axial movement of the piston rod base (2b; 2b'; 2b”) to the piston rod means (2a; 2a'; 2a”) -axial stop between the distal end of the piston rod base (2b; 2b'; 2b”) and the plug (3a; 3a'), wherein the distal end of the piston rod base (2b; 2b'; 2b”) and the plug (3a; 3a') come to rest against each other.

6. Method according to claim 5, characterized in that during the relative rotation between the insert (4; 4'; 4") and the piston rod means (2a; 2a'; 2a") or the piston rod base (2b; 2b'; 2b") in the first direction of rotation, the rotational force increases to indicate, upon reaching a threshold value, that the distal end of the piston rod base (2b; 2b'; 2b") is in axial abutment contact with the plug (3a; 3a').

7. Method according to claim 5 or 6, characterized in that the insert (4; 4'; 4") can be rotated relative to the piston rod means (2a; 2a'; 2a") or to the piston rod base (2b; 2b'; 2b") in the first direction of rotation and that a relative rotation between the insert (4; 4'; 4") and the piston rod means (2a; 2a'; 2a") or the piston rod base (2b; 2b'; 2b") in a second direction of rotation opposite to the first direction of rotation is blocked.

8. Method according to one of claims 5 to 7, characterized in that the insert (4; 4'; 4") can engage, in particular in a rotationally fixed engagement, with a tool (9; 9') and the tool (9; 9') can rotate the insert (4; 4'; 4") relative to the piston rod means (2a; 2a'; 2a") or the piston rod base (2b; 2b'; 2b") in the first direction of rotation.

9. Method according to one of claims 5 to 8, characterized in that the axial distance between the piston rod base (2b; 2b'; 2b”) and the plug (3a; 3a') is determined such that a distal end of the piston rod base (2b; 2b'; 2b”) and the plug (3a; 3a') come to rest against each other.

10. The method according to one of claims 5 to 9, characterized in that in one step a container holder (5; 5') received with the container (3; 3') is axially fixedly connected, in particular snapped, plastically deformed, screwed, glued or welded, to the housing (1; 1') receiving the piston rod base (2b; 2b'; 2b"), the piston rod means (2a; 2a'; 2a") and the insert (4; 4'; 4"), and in a further step the axial distance between the piston rod base (2b; 2b'; 2b") and the plug (3a; 3a') of the injection device is determined such that a distal end of the piston rod base (2b; 2b'; 2b") and the plug (3a; 3a') come to rest against one another.

11. Method according to claim 10, characterized in that the insert (4; 4”) with an external thread (4a; 4a”) is screwed into the piston rod means (2a; 2a”) with an internal thread (2d; 2d') and the piston rod foot (2b; 2b”) is inserted through the distal end of the piston rod means (2a; 2a”).

12. Method according to claim 10, characterized in that the insert (4') with an external thread (4a') is screwed into the piston rod base (2b') with an internal thread (2g) and the piston rod base (4b) received with the insert (4') is inserted into the piston rod means (4a).

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