CH715854A2 - Delivery device with coupling mechanism. - Google Patents

Abstract

The invention relates to an administration device comprising a housing (10), a carpule holder (13) which can be detachably connected to the housing (10), a piston rod (60), a drive sleeve (40) and a first coupling part (90) rotatable relative to the housing (10), a second coupling part (110) axially displaceable relative to the housing (10) and a third coupling part (120) connected non-rotatably to the piston rod (60) and axially displaceable relative to the piston rod (60) and the housing (10). The carpule holder (13) can be connected to or separated from the housing (10) by at least one rotational movement relative to the housing (10), the first coupling part (90) being rotated by the rotational movement. The first and second coupling parts (90, 110) are coupled to one another with a cam gear, so that a rotation of the first coupling part (90) causes an axial displacement of the second coupling part (110). The third coupling part (120) is rotatively coupled or decoupled from the drive sleeve (40) due to the axial displacement.

Description

TECHNICAL AREA

The present invention relates to the field of medical administration devices for administering liquid substances, in particular medicaments or medicinal substances such as insulin and hormone preparations. The invention relates to an administration device with a coupling mechanism.

BACKGROUND OF THE INVENTION

Known injection devices comprise a housing with a dosing and dispensing mechanism and a carpule holder. This is connected to the housing and holds a cartridge with a medicinal substance.

To set a dose, the user turns or pulls on a dosing element of the dosing and dispensing mechanism, the dosing element being unscrewed or moved out of the housing of the injection device. So that the dose set in this way can be poured out, the user presses a pouring button at a proximal end of the injection device and thereby generates a force in the distal direction, whereby the dosing element is screwed or pushed into the housing. In contrast to setting a dose, when pouring out the dosing element transfers the rotary or sliding movement to a drive sleeve or coupling sleeve, which thereby drives a piston rod in order to pour the substance out of the carpule. Depending on the design, the piston rod can be rotated or screwed or can only be moved relative to the housing.

[0004] Disposable injection devices (disposable) are disposed of after the entire contents of the carpule have been poured out. In the case of reusable injection devices, the carpule in the injection device can be exchanged for a new carpule. For this purpose, the carpule holder is separated from the housing so that the carpule can be exchanged. Furthermore, the piston rod, which is in a distal end position, must be returned to a proximal starting position so that the injection device is ready to pour out the contents of the new, full carpule. The extended piston rod is usually pushed back into the housing of the injection device in the proximal direction by the user. To do this, however, the piston rod must be decoupled from the drive element (e.g. the drive sleeve), as a reverse rotation lock (e.g. in the form of a one-way ratchet) would prevent the piston rod from being pushed back. This optional coupling of the piston rod with the drive element or decoupling of the piston rod from the drive element of the dosing and dispensing mechanism is made possible by a return mechanism or reset mechanism.

Such a return mechanism must on the one hand enable the piston rod to be pushed back into the housing into an initial position when the carpule holder is removed from the housing and, on the other hand, ensure that the piston rod is reliably coupled to the drive element when the carpule holder is completely connected to the housing is, so that a dispensing movement of the dispensing element is reliably transmitted to the piston rod.

DISCLOSURE OF THE INVENTION

[0006] It is an object of the invention to enable a reusable administration device to be reliably reset when the carpule is changed.

[0007] This object is achieved by an administration device according to the independent claim. Preferred embodiments are the subject of the dependent claims.

According to the invention, the administration device, in particular an injection device, for pouring out a dose of a product from a carpule held in the administration device comprises a housing which defines an axial direction or a longitudinal axis, a carpule holder which is releasably connected to a distal end of the housing can be connected, a piston rod and a drive sleeve for driving the piston rod in a distal direction for discharging the product from the carpule. The administration device according to the invention further comprises a first coupling part which is rotatable relative to the housing, a second coupling part which is axially displaceable relative to the housing and a third coupling part which is non-rotatably connected to the piston rod and axially displaceable relative to the piston rod and relative to the housing. The carpule holder can be connected to the housing or separated from the housing by at least one rotational movement relative to the housing, the first coupling part being rotated by the rotational movement. The first and the second coupling part are coupled to one another with a cam gear, which is designed such that the rotary movement of the first coupling part causes an axial displacement of the second coupling part, the third coupling part being rotatably coupled or decoupled from the drive sleeve by the axial displacement.

The carpule holder is attached to the housing with at least a rotary movement (or a combination of a rotary movement and an axial movement) relative to the latter, for example by means of a screw connection or by means of a bayonet lock.

By means of the cam gear, a rotary movement of the carpule holder relative to the housing can be easily transferred into a linear, axial displacement movement of the second coupling part.

If the third coupling part, which alternatively couples the drive sleeve with the piston rod rotatively or decoupled directly interact with the carpule holder, there is a risk that the third coupling part will be rotated unintentionally. Since the third coupling part is non-rotatably connected to the piston rod, the piston rod would also rotate as a result, which would result in an unintentional discharge or an undesired backward movement of the flange.

If, however, according to the invention, the third coupling part (rotatably connected to the piston rod) is actuated by a pure axial movement in order to couple or decouple the drive sleeve rotatively with the piston rod, unwanted rotation of the piston rod can be reliably avoided.

The first and the second coupling part are coupled to one another with a cam gear. The cam gear enables a rotary movement of the first coupling part to be transferred or translated into an axial movement of the second coupling part. The second coupling part is preferably only displaced axially and does not rotate.

The cam gear preferably comprises a cam carrier and a tap member, wherein the first or the second coupling part forms the cam carrier and the other of the first or the second coupling part comprises the tap member. The curve support specifies the sequence of movements and / or the direction of movement and the pick-off element is forced by the curve or the shape of the curve support along this specified sequence of movements and / or the specified direction of movement.

To replace a carpule, the carpule holder can be released or separated from the housing with at least one rotary movement relative to the latter. The first coupling part is preferably also rotated by the rotary movement. The cam gear transmits this rotary movement of the first coupling part into an axial displacement movement of the second coupling part, and the second coupling part is preferably displaced in the distal direction. As a result, the third coupling part axially connected to the second coupling part is also displaced distally. As a result of this displacement, the third coupling part is no longer in engagement with the drive sleeve. The piston rod with the third coupling part can then rotate relative to the drive sleeve. The piston rod can then be pushed back from a distal end position into a proximal starting position.

After resetting the piston rod and replacing the carpule, the carpule holder can be reconnected to the housing. In order to connect the carpule holder to the housing, the first coupling part is turned back. The cam mechanism translates this rotary movement of the first coupling part into an axial displacement movement of the second coupling part, preferably in the proximal direction. The third coupling part, which is axially connected to the second coupling part, is thereby also displaced axially in the proximal direction. This brings the third coupling part back into engagement with the drive sleeve. The third coupling part thus rotatively couples the drive sleeve to the piston rod, so that a rotary movement is transmitted from the drive sleeve to the piston rod.

The administration device is preferably designed as an injection device and particularly preferably as a reusable injection device (also referred to as "reusable"), in which, after the contents of the carpule have been poured out, the carpule can be replaced and the injection device can be replaced with the new carpule can be used. In contrast, a disposable injection device, which is also referred to as “disposable”, is disposed of after one or more injection processes, but at the latest after the last dose that can be dispensed. The carpule cannot be exchanged in such a disposable injection device.

The injection device comprises a housing in which a dosing and dispensing mechanism and also the reset mechanism are located.

In the present description, the term “distal” denotes a side or direction directed towards the front, insertion-side end of the injection device or towards the tip of the injection needle. In contrast, the term “proximal” denotes a side or direction directed towards the rear end of the injection device opposite the end of the injection device.

The term axial refers to the longitudinal axis of the housing. Correspondingly, an axial direction is parallel to the longitudinal axis of the housing or in the longitudinal direction of the housing. A radial direction refers to a direction perpendicular to the longitudinal axis of the housing.

The term “product”, “drug” or “medicinal substance” in the present context includes any flowable medical formulation that is suitable for controlled administration by means of a cannula or hollow needle into subcutaneous or intramuscular tissue, for example a liquid, a solution, a gel or a fine suspension containing one or more medicinal active ingredients. Thus, a medicament can be a single agent composition or a premixed or co-formulated multiple agent composition from a single container. The term includes in particular drugs such as peptides (e.g. insulins, insulin-containing drugs, GLP 1-containing and derived or analogous preparations), proteins and hormones, biologically obtained or active ingredients, active ingredients based on hormones or genes, nutritional formulations, enzymes and other substances in solid (suspended) or liquid form. The term also includes polysaccharides, vaccines, DNA or RNA or oligonucleotides, antibodies or parts of antibodies as well as suitable basic, auxiliary and carrier substances.

The terms “injection device” or “injector” in the present description are understood to mean a device in which the injection needle is removed from the tissue after a controlled amount of the medical substance has been dispensed. Thus, in the case of an injection system or an injector, in contrast to an infusion system, the injection needle does not remain in the tissue for a long period of several hours.

The term “non-rotatably” means that no relative rotational movement is possible. For example, according to the invention, the third coupling part is non-rotatably connected to the piston rod. This means that the third coupling part cannot rotate relative to the piston rod. The term “rotatively coupled or decoupled” means that in a rotationally coupled state no relative rotational movement is possible, while in a rotationally decoupled state a relative rotational movement can take place between two parts.

In a preferred embodiment, the cam mechanism is formed by a guide groove in one of the first or second coupling part and by a guide cam on the other of the first or second coupling part. The guide cam is guided through the guide groove, whereby the rotational movement of the first coupling part in a linear and axial displacement of the second coupling part can be transmitted relative to the building. The second coupling part is then preferably only displaced axially and does not rotate.

The axial displacement of the second coupling part preferably causes an axial displacement of the third coupling part relative to the piston rod and also relative to the housing, whereby the third coupling part couples or decouples the drive sleeve with the piston rod. As a result of the axial displacement, the third coupling part is preferably brought into engagement with the drive sleeve or the engagement is canceled.

Since the third coupling part is always rotatably connected to the piston rod, the drive sleeve is rotatively coupled to the piston rod when the third coupling part is coupled to the drive sleeve. The delivery device is then in a coupled state in which it is ready for delivery. If, on the other hand, the third coupling part is not coupled to the drive sleeve, the administering device is in a decoupled state in which the piston rod can be reset by the user (reset movement).

Preferably, the second and the third coupling part are immovably connected to one another in the axial direction or are connected to one another in an axially fixed manner. As a result, when the second coupling part moves axially, the third coupling part is also shifted axially.

The first, second and third coupling parts are preferably designed in the form of a sleeve. The third coupling part is preferably located in a coupled state at least partially within the drive sleeve. This enables a space-saving arrangement.

[0029] The first coupling part is preferably designed as an actuating sleeve which can optionally be rotatively coupled to the carpule holder. The second coupling part is then preferably designed as a sleeve-shaped coupling ring which is coupled to the actuating sleeve by the cam mechanism. The third coupling part, which is connected to the piston rod in a rotationally fixed but axially displaceable manner, is preferably displaced axially distally or proximally by the coupling ring.

In a preferred embodiment, the first coupling part comprises an engagement element which can engage with a counter-engagement element in the carpule holder for the optional rotational coupling of the first coupling part to the carpule holder. The engagement element and the counter-engagement element can be coupled, for example, in the form of a keyway connection, so that there is a rotationally fixed connection.

Preferably, the first coupling part is mounted axially displaceable relative to the housing. The administering device further comprises an elastic element (for example a spring or an elastic plastic), by means of which the first coupling part can be pretensioned in the distal direction. This can ensure that the carpule is pressed with a pretensioning force against a distal stop in the carpule holder. The carpule is thus held immovably in the carpule holder by the elastic element and the first coupling part. Different lengths of the carpules (due to manufacturing tolerances) can also be compensated for with the elastic element.

In a preferred embodiment, the injection device comprises a ratchet element with ratchet arms, which are designed to interact with counter elements such as teeth or projections on the housing. The ratchet element allows the drive sleeve to rotate relative to the housing in a first direction of rotation (discharge direction) and prevents the drive sleeve from rotating relative to the housing in a second direction of rotation (dosing direction).

[0033] The ratchet element is preferably designed as a single, separate component. The ratchet element is therefore not formed in one piece with the housing or any other element. This simplifies the manufacture of the ratchet element. The ratchet element is preferably held non-rotatably on the housing, for example by means of a form fit or by a snap connection.

The ratchet element is preferably made essentially from a metallic material. For example, the ratchet element can be produced as a stamped and bent part from sheet metal.

CHARACTERS

Preferred embodiments of the invention are described below in connection with the attached figures. These are intended to show the basic possibilities of the invention and are in no way intended to be interpreted as restrictive. <tb> Fig. 1 <SEP> shows in a perspective view an exploded view of the administration device according to the invention in the form of an injection pen; <tb> Fig. 2 <SEP> shows a perspective view of a drive sleeve of the injection pen; <tb> Fig. 3a <SEP> shows a side view of an actuation sleeve of the injection pen; <tb> Fig. 3b <SEP> shows a perspective view of the actuating sleeve from FIG. 3a; <tb> Fig. 4a <SEP> shows a sectional view of the injection pen, the section running through the longitudinal axis; <tb> Fig. 4b <SEP> shows an enlargement of the proximal end area of the injection pen from FIG. 4a; <tb> Fig. 5 <SEP> shows the injection pen after setting a dose; <tb> Fig. 6 <SEP> shows the injection pen after the dose has been poured out; <tb> Fig. 7 <SEP> shows the housing in the uncoupled state without a carpule holder and without a carpule; <tb> Fig. 8 <SEP> shows the injection pen in the coupled state; <tb> Fig. 9 <SEP> shows a perspective external view of the injection pen with the protective cap fitted; <tb> Fig. 10 <SEP> shows an external view without a protective cap; <tb> Fig. 11 <SEP> shows a further external view; <tb> Fig. 12 <SEP> shows an external view of the proximal end area of the injection pen.

FIGURE DESCRIPTION

FIG. 1 shows an administration device according to the invention in the form of an injection pen in an exploded view. For this description, the single-sided end of the injection pen 1 is referred to as the distal end and the end of the injection pen 1 opposite the single-sided end is referred to as the proximal end. Correspondingly, the direction towards the needle or injection site is called the distal direction and the direction away from the needle is called the proximal direction. In FIG. 1, the distal, penetration-side end of the injection pen 1 is accordingly in the left, lower area and the proximal end of the injection pen 1 in the right, upper area.

In the embodiment shown, the injection pen 1 is designed as a reusable injection pen 1. As can be seen in FIG. 1, the injection pen 1 comprises a removable protective cap 5, an elongated, cylindrical housing 10, a dosing and dispensing mechanism in the housing and a carpule holder 13 in which a carpule 6 with a medical substance is held.

Dosing and dispensing mechanism

The metering and dispensing mechanism of the injection pen 1 is described in detail below. The reset mechanism for replacing a carpule is then explained.

In the description of the dosing and dispensing mechanism, the structural features of the individual components are discussed first. Then the functions, in particular setting, correcting and dispensing a dose, are described.

Within the housing 10, the injection pen 1 comprises an inner housing sleeve 15 fixed to the housing, a dosing sleeve 20 for setting and correcting a dose, a display sleeve 28, a coupling sleeve 30, a drive sleeve 40 and a piston rod 60 arranged inside the drive sleeve 40, which is driven by the drive sleeve 40 can be driven to dispense the medical substance from the carpule 6. The injection pen 1 also includes a dispensing button 70 at the proximal end for triggering the dispensing process.

The carpule holder 13 can be detachably connected to the housing 10 in a distal end region of the housing 10 by means of a bayonet lock. The carpule holder 13 supports the carpule 6 and has at its distal end a connecting element to which an injection needle or injection cannula (not shown) can be attached.

Furthermore, the carpule holder 13 has two cams 14 in the proximal end region in order to connect the carpule holder 13 to the housing 10. In addition, there are two engagement elements in the form of grooves 15 in the proximal end area, which are used for rotational connection to an actuating sleeve 90.

The housing 10 is designed in the form of a sleeve. In a proximal area, a radial opening or opening 11 is formed in the jacket of the housing sleeve. A number scale on the display sleeve 28 can be read from the outside through this opening 11.

The inner housing sleeve 15 has a cylindrical shape and is arranged coaxially to the outer housing sleeve of the housing 10. By means of snaps, which engage in a wall on the inside of the housing 10, the inner housing sleeve 15 is snapped onto the housing 10 in an immovable manner both in the axial direction and in rotation relative to the latter.

In addition, the housing sleeve 15 has in a proximal area on its inside a threaded segment 16 which is in threaded engagement with an external thread 22 of the dosing sleeve 20. In the proximal area, an axially aligned web is also formed (not shown). The maximum adjustable individual dose or the screwing movement of the dosing sleeve 20 out of the housing sleeve 15 is limited by this web. The inner housing sleeve 15 thus supports the metering sleeve 20 rotatably relative to the housing 10.

The dosing sleeve 20 has the shape of a hollow cylinder or a sleeve and has at the proximal end an area with a diameter which is larger than the rest of the area of the dosing sleeve 20 and which serves as a handle 21 for turning the dosing sleeve 20. This handle 21 does not fit into the housing 10, but, as can be seen in FIG. 4, is at the proximal end of the housing 10. At the proximal end of the handle 21, the handle has an inwardly pointing circumferential bead 26, likewise recognizable in FIG. 2.

In the area of the handle, the dosing sleeve 20 has a larger inside diameter. At the transition from the area of the smaller inside diameter to the area of the larger inside diameter, there is an annular surface in the interior of the dosing sleeve 20 which is at right angles to the longitudinal axis. Axial teeth 25 are arranged circumferentially on this surface.

As mentioned, the metering sleeve 20 is threadedly connected to the inner housing sleeve 15. For this purpose, the metering sleeve 20 has an external thread 22 on its outside. At the distal end of the external thread 22, the dosing sleeve 20 comprises an axially aligned and radially protruding web as a stop element 23, which strikes the axial web of the inner housing sleeve 15 in a proximal end position of the dosing sleeve 20.

The display sleeve 28 has on its outside a number scale which shows the user the adjustable doses. At the proximal end, the display sleeve 28 comprises two grooves 29 distributed over the circumference, in which webs 24 of the metering sleeve 20 engage (FIG. 4) in order to connect the display sleeve 28 to the metering sleeve 20 in a rotationally fixed manner. The display sleeve 28 is arranged outside the housing sleeve 15 while the dosing sleeve 20 is located inside the housing sleeve 15. Behind the proximal end of the housing sleeve 15, the display sleeve 28 and the metering sleeve 20 are connected to one another in a rotationally fixed manner with the above-mentioned grooves 29 and webs 24.

The hollow cylindrical, elongated coupling sleeve 30 has on its inside a plurality of webs 31 which are arranged over the circumference and project towards the center and can be seen in FIG. In addition, the coupling sleeve 30 has a circumferential collar 32 in a proximal area, which has a distal and a proximal annular surface. On the distal surface there are four teeth 33 which are distributed over the circumference and point in the axial direction and, as described below, can interact with the axial teeth 25 of the dosing sleeve 20.

In a proximal end region, the coupling sleeve 30 also has grooves 34 on the inside (see FIG. 4). Web 78 of a spring holder 76 can engage in this, so that the spring holder 76 is connected to the coupling sleeve 30 in a rotationally fixed manner.

The spring holder 76 comprises a cylindrical section with a non-through bore from the proximal side. The spring holder 76 further comprises a plate-shaped collar 77 at the proximal end. The cylindrical section is located inside the coupling sleeve 30. Between the distal surface of the collar 77 of the spring holder 76 and the proximal surface of the collar 32 of the coupling sleeve 30 is a coupling spring 75 in the form of a metallic compression spring held.

The dispensing button 70 is arranged proximal to the spring holder 76. This has an axial support 72 which is located within the sleeve-shaped section of the spring holder 76. The dispensing button 70 further comprises a circumferential shoulder 71, which is snapped over the circumferential bead 26 of the dosing sleeve 20. This limits a movement of the dispensing button 70 relative to the dosing sleeve 20 in the proximal direction. In the distal direction, the dispensing button 70 is supported with its support 72 on the bottom of the bore of the spring holder 76. The dispensing button 70, the coupling spring 75 and the spring holder 76 are thereby held axially displaceably between the coupling sleeve 30 and the dosing sleeve 20.

The piston rod 60 comprises an external thread 61 with which it is screwed into an internal thread 82 (FIG. 4) of a threaded insert 80 fixed to the housing. As can be seen in FIG. 1, the piston rod 60 has two grooves 62 which are offset by 180 ° in the circumferential direction and which extend over the entire axial length of the piston rod 60. Struts 45 of the drive sleeve 40 engage in these grooves 62, whereby the drive sleeve 40 is connected to the piston rod 60 in a rotationally fixed but axially displaceable manner.

At the distal end of the piston rod 60 is a button-shaped end of the piston rod 60, which enables a snap connection with a flange 63, whereby the flange 63 is rotatable relative to the piston rod 60, but is held firmly in the axial direction on the piston rod 60. The flange 63 can act on a stopper in the carpule 6 in order to pour the medical substance out of the carpule 6.

In FIG. 2, the drive sleeve 40 is shown enlarged in a perspective view. The drive sleeve 40 is also cylindrical and has axial grooves 41 on its outside, in which the webs 31 of the coupling sleeve 30 are received, so that the drive sleeve 40 and the coupling sleeve 30 are connected to one another in a rotationally fixed manner. At the distal end of the drive sleeve 40 there is a circumferential collar 42. On its proximal annular surface, saw teeth 43 are arranged in the circumferential direction, which, as described below, interact with ratchet arms 52 of a click spring 50.

In a distal end region, the drive sleeve 40 has a plurality of radially inwardly pointing webs 45 on its inside (visible in FIG. 1) which can be brought into engagement with grooves 121 of a coupling part 120.

Compared to the drive sleeve 40, this coupling part 120 has only a short axial length. On the outside, the coupling part 120 has the grooves 121 just mentioned, and a circumferential edge at the distal end. On the inside of a through hole there are webs 122 which point radially inward and which engage in the grooves 62 of the piston rod 60. As a result, the coupling part 120 is always connected to the piston rod 60 in a rotationally fixed manner, but is mounted so as to be axially displaceable relative to the piston rod 60.

The dosing and dispensing mechanism further comprises a click spring 50. This is manufactured as a metal stamped and bent part and comprises a ring 51 to which two ratchet arms 52 are attached, which protrude axially from the ring 51 in the distal direction. The ratchet arms 52 are resilient relative to the ring 51. The click spring 50 is supported on the proximal side against a stop on the housing sleeve 15 fixed to the housing and on the distal side the ratchet arms 52 press into the saw teeth 43 of the drive sleeve 40. By means of prongs 54 on the ring 51, the click spring 50 is rotationally fixed relative to the housing 10 held on to this. Since the click spring 50 is slightly compressed, it is ensured that the ratchet arms 52 are always in engagement with the saw teeth 43 of the drive sleeve 40. Both ratchet arms 52 each have an angled end section 53 at their free end, which is designed to slide over the saw teeth 43 in a discharge direction when the drive sleeve 40 rotates relative to the housing 10 in the discharge direction. In the opposite direction (adjustment direction), the angled end sections 53 of the ratchet arms 52 abut against stop surfaces of the saw teeth 43, whereby a rotation of the drive sleeve 40 relative to the housing 10 is prevented.

The function of the dosing and dispensing mechanism is explained in detail below.

In FIG. 4, the injection pen 1 is shown in a longitudinal section in an initial position. To set a dose, the dosing sleeve 20 is rotated on its handle 21 relative to the housing 10 in the setting direction relative to the housing 10. Since the dosing sleeve 20 is in threaded engagement with the inner housing sleeve 15, it is thereby screwed out of the housing sleeve 15. The display sleeve 28 is non-rotatably connected to the dosing sleeve 20 and thus also rotates. The number scale printed on the display sleeve 28 can be seen through the openings 11 in the housing 10 and helps to set the desired dose.

The coupling sleeve 30 is prevented from rotating in the setting direction by means of the drive sleeve 40 and the ratchet arms 52 of the click spring 50 because the angled end sections 53 of the ratchet arms 52 abut the stop surfaces of the saw teeth 43 of the drive sleeve 40. Since the coupling sleeve 30 is prevented from rotating in the adjustment direction, the piston rod 60 connected to it in a rotationally fixed manner via the coupling part 120 is also prevented from rotating in the adjustment direction.

In FIG. 5, the injection pen 1 is shown in a sectional view after a dose has been set. If too high a dose is accidentally set, the dose can be corrected by screwing the dosing sleeve 20 back into the housing 10. The coupling sleeve 30 is still rotatably held relative to the housing 10, since the frictional force to move the pretensioned ratchet arms 53 over the saw teeth 43 is greater than the frictional force between the teeth 25 of the dosing sleeve 30 and the teeth 33 of the coupling sleeve 30. Consequently, can when setting and correcting a dose, when the dosing sleeve 30 is rotated in the setting direction or in the delivery direction (to correct a dose), the coupling sleeve 30, the drive sleeve 40, the coupling part 120 and thus the piston rod 60 do not rotate.

Since the dosing sleeve 20 rotates relative to the coupling sleeve 30 when setting and correcting a dose, the axial teeth 25 of the dosing sleeve 20 slide over the teeth 33 of the coupling sleeve 30 and thereby generate a clicking noise and vibrations. In this way, acoustic as well as tactile feedback is generated for the user in the setting direction (increasing the dose) and also in the delivery direction (reducing the dose).

FIG. 6 shows the injection pen 1 in a sectional view after the set dose has been poured out. To dispense the set dose, the user presses the dispensing button 70 in the distal direction. As a result, the coupling spring 75 is compressed and the coupling sleeve 30 is displaced axially in the distal direction relative to the dosing sleeve 20 via the spring holder 76. The teeth 33 of the coupling sleeve 30 are brought into engagement with the axial teeth 25 of the metering sleeve 20 by this displacement, as a result of which the coupling sleeve 30 is rotatively coupled to the metering sleeve 20.

Due to the distal force when the user presses the dispensing button 70, the dosing sleeve 20 is screwed back into the housing 10. This means that the frictional force between the ratchet arms 52 and the saw teeth 43 is overcome and the ratchet arms 52 slide over the saw teeth 43, whereby the coupling sleeve 30 can rotate relative to the housing 10 in the discharge direction. This means that the coupling sleeve 30 is also rotated relative to the housing 10 by the rotating dosing sleeve 20. As a result, the drive sleeve 40, which is connected non-rotatably to the coupling sleeve 30 and which also drives the piston rod 60 via the coupling part 120, is rotated. The piston rod 60 screws through the internal thread 82 in the threaded insert 80, as a result of which the flange 63 at the distal end of the piston rod 60 is axially displaced relative to the housing 10 and thus displaces the stopper located in the carpule 6 in the distal direction. As a result, the medical substance is released from the carpule 6.

The flexible ratchet arms 52 of the click spring 50 are moved during the rotation of the coupling sleeve 30 in the discharge direction over the saw teeth 43 of the coupling sleeve 30, whereby a clicking noise and a vibration are generated.

Reset mechanism

The reset mechanism (reset mechanism) of the injection pen 1 is explained below. This serves to reset the injection pen 1 when the entire contents of the carpule 6 has been poured out and the carpule 6 in the carpule holder 13 has to be replaced. First, the structural features are explained. The function of the reset mechanism is then described.

In FIG. 7, the injection pen 1 without carpule holder, carpule and protective cap is shown in a decoupled state in a sectional view. In the figure 8 the injection pen 1 is shown with the mounted carpule holder and carpule in the coupled-in state.

The reset mechanism comprises the threaded insert 80, an actuating sleeve 90, a coupling ring 110 and the coupling part 120, which are all arranged within the housing 10. The actuating sleeve 90, the coupling ring 110 and the coupling part 120 surround the piston rod 60.

The threaded insert 80 is held immovable relative to the housing 10 by means of a snap connection. It is sleeve-shaped and has a bayonet guide 81 in its outer surface in the form of elongated grooves, see Figure 1. The bayonet guide 81 serves to guide cams 14 of the carpule holder 13. As can be seen in Figure 7, the threaded insert 80 has an axial inside Guide 83 to guide the coupling ring 110 axially and non-rotatably. In addition, the actuating sleeve 90, the carpule spring 85 and the coupling ring 110 are arranged within the threaded insert 80.

The coupling ring 110 is connected axially fixed to the coupling part 120 by means of a snap lock. Furthermore, the coupling ring 110 is axially displaceably mounted within the threaded insert 80 through the guide 83 in the threaded insert 80. The coupling ring 110 has guide cams 111 pointing radially outward on its outside (can be seen in FIG. 1). In addition, the coupling ring 110 is partially located within the actuation sleeve 90.

The actuating sleeve 90 is shown enlarged in FIGS. 3a and 3b. It is cylindrical and rotatably mounted within the threaded insert 80. At its distal end it has two coupling cams 92 which can engage in correspondingly shaped grooves in the carpule holder 13 in order to couple the carpule holder 13 to the actuating sleeve 90 in a rotative manner. In addition, the actuating sleeve 90 has guide grooves 91 in its outer surface. The guide cams 111 of the coupling ring 110 are guided in these guide grooves 91. Guide grooves 91 and guide cams thus form a cam mechanism between the actuating sleeve 90 and the coupling ring 110. The guide grooves 91 each have three interconnected sections 93, 94, 95, as can be seen in FIG. 3a. In a first section 93, the guide groove 91 runs in the circumferential direction, at right angles to the longitudinal axis of the injection pen 1. In a second, inclined section 94, the guide groove runs obliquely, that is, both in the circumferential direction and in the proximal direction (similar to a thread). In a third section 95, the guide groove 91 again runs only in the circumferential direction. The function of this cam mechanism with guide groove 91 and guide cam 111 is explained in detail below.

The actuating sleeve 90 is mounted axially displaceably in the threaded insert 80 which is fixed to the housing. As can be seen in FIG. 7, there is a carpule spring 85 on a proximal side of the actuation sleeve 90. This is slightly compressed and is supported on the proximal side on the threaded insert 80 and on the distal side on the actuation sleeve 90 a distal stop in the threaded insert 80 is biased in the distal direction.

When the medical substance has been completely poured out of the carpule 6, the carpule 6 in the injection pen 1 must be replaced. For this purpose, the carpule holder 13 is first rotated by an angular range relative to the housing 10 and then pulled out of the housing 10 with a pulling movement in the distal direction. As a result, the cams 14 are guided out of the bayonet guide 81 and the bayonet connection between the carpule holder 13 and the housing 10 is released. During the rotary movement of the carpule holder 13, the actuating sleeve 90, which is rotatively coupled to the carpule holder 13, is also rotated. Since the coupling ring 110 is axially guided in the housing sleeve 80 but cannot rotate, the actuating sleeve 90 rotates relative to the coupling ring 110. As a result, the guide grooves 91 are displaced relative to the guide cams 111. Due to the incline in the inclined section 94 of the guide groove 91, the guide cams 111 and thus the entire coupling ring 110 are displaced axially in the distal direction relative to the housing 10. Since the coupling ring 110 is connected axially fixed to the coupling part 120, the coupling part 120 is also displaced relative to the housing 10 and also relative to the piston rod 60 due to the axial displacement. This has the consequence that the coupling part 120 is pulled out of the drive sleeve 40 in the distal direction. As a result, the rotary coupling between drive sleeve 40 and coupling sleeve 30 and thus also between drive sleeve 40 and piston rod 60 is canceled. The piston rod 60 can thus be freely rotated together with the coupling part 10. The piston rod 60 can thus be pushed back into the housing 10 in the proximal direction by the user in order to reset the injection pen 1 and prepare it for a new injection. The piston rod 60 is screwed in the proximal direction through the internal thread 82 in the threaded insert 80.

After the new carpule 6 has been inserted in the carpule holder 13, the carpule holder 13 is inserted with its proximal end region into the distal region of the housing 10 or of the threaded insert 80 in the axial direction. The cams 14 of the carpule holder are received in the bayonet guide 81 of the threaded insert 80. By axially pushing the proximal end region of the carpule holder 13 into the housing 10, the grooves in the carpule holder 13 are also brought into engagement with the coupling cams 92 at the distal end of the actuating sleeve 90. Carpule holder 13 and actuating sleeve 90 are thereby rotationally coupled to one another.

In order to completely connect the carpule holder 13 to the housing 10, the axial movement must be followed by a rotational movement of the carpule holder 13 relative to the housing 10 (bayonet connection). During this rotational movement, the actuating sleeve 90 is also rotated relative to the housing 10. The coupling ring 110, on the other hand, is held non-rotatably relative to the housing 10 by the threaded insert 80. It cannot turn with it. This relative rotation between the actuating sleeve 90 and the coupling ring 110 has the consequence that the guide groove 91 is displaced relative to the guide cams 111. The guide cams 111 and thus the entire coupling ring 110 are pressed axially in the proximal direction by the inclined section 94 of the guide groove 91 (due to the cam mechanism). Since the coupling part 120 is axially fixedly connected to the coupling ring 110, the coupling part is also displaced in the proximal direction relative to the housing 10 and also relative to the piston rod 60. The grooves 121 of the coupling part 120 are thereby brought into engagement with the webs 45 of the drive sleeve 40. This means that the coupling part 120 is pushed into the drive sleeve 40 and rotatively coupled to it. As a result, the drive sleeve 40 is non-rotatably coupled to the piston rod 60 via the coupling part 120, which is always connected non-rotatably to the piston rod 60. A rotation of the drive sleeve 40 in this coupled-in state thus results in a rotation of the piston rod 60. The injection pen 1 is now in the coupled state again.

Due to the compressed carpule spring 85, which pretensions the actuating sleeve 90 in the distal direction, a spring force acts on the carpule 6 in the distal direction. As a result, the carpule 6 is pretensioned in the carpule holder 13 and held immovable.

All parts with the exception of the clutch spring 75, the carpule spring 85 and the carpule are made of plastic, preferably of polypropylene. The clutch spring and carpule spring are made of spring steel.

In FIGS. 9 to 12, the injection pen 1 according to the invention is shown in perspective external views. In FIG. 9, an external view of the injection pen 1 with the protective cap 5 put on is shown. Also visible in this view are the housing 10, the opening 11 in the housing 10 through which the numerical scale of the display sleeve 28 can be seen, the handle 21 of the dosing sleeve 20 and the dispensing button 70.

FIG. 10 shows the injection pen 1 without a protective cap 5. This view shows a needle protecting sleeve 7 snapped onto the distal end of the carpule holder 13, which protects the injection needle (not shown) and which must be removed before an injection. Nubs 8 can also be seen on the proximal end of the carpule holder 13. When the protective cap 5 is in place, these knobs 8 engage in correspondingly shaped depressions on the inside of the protective cap 5. As a result, the protective cap 5 is held in a specific rotational orientation on the housing 10 or on the carpule holder 13 by means of a snap connection. Part of the carpule 6 can be seen through an elongated, axial recess in the carpule holder 13.

FIG. 11 shows a further perspective external view of the injection pen 1 from a side which is opposite the side shown in FIG. In other words, FIG. 11 shows the injection pen 1 from FIG. 10 rotated by 180 ° about its longitudinal axis.

FIG. 12 shows the proximal end area of the injection pen 1, the viewing direction running from proximal to distal. It can be seen in this view that a company logo 9 or company logo of the manufacturer of the injection pen 1 is formed by depressions in a proximal end surface of the dispensing button 70.

REFERENCE LIST

1 injection pen 5 protective cap 6 carpule 7 needle protection sleeve 8 knobs 9 company logo 10 housing 11 opening 13 carpule holder 14 cams 15 inner housing sleeve 16 threaded segment 20 dosing sleeve 21 handle 22 external thread 23 stop element 24 web 25 axial teeth 26 bead 28 indicator sleeve 29 grooves 30 coupling sleeve 31 Web 32 Collar 33 Teeth 34 Grooves 40 Drive Sleeve 41 Grooves 42 Collar 43 Saw Teeth 45 Web 50 Click Spring 51 Ring 52 Ratchet Arms 53 End Sections 54 Prongs 60 Piston Rod 61 External Thread 62 Grooves 63 Flange 70 Discharge Button 71 Paragraph 72 Support 75 Clutch Spring 76 Spring Holder 77 Collar 78 Web 80 Threaded insert 81 bayonet guide 82 internal thread 83 axial guide 85 carpule spring 90 actuating sleeve 91 guide groove 92 coupling cams 93 first section 94 inclined section 95 third section 110 coupling ring 111 guide cams 120 coupling part 121 grooves 122 webs

Claims (11)

Claims 1. An administration device (1) for dispensing a dose of a product from a carpule (6) held in the administration device, comprising the administration device (1) a housing (10) defining an axial direction; a carpule holder (13) which is releasably connectable to the housing (10); a piston rod (60); a drive sleeve (40) for driving the piston rod (60); a first coupling part (90) rotatable relative to the housing (10); a second coupling part (110) axially displaceable relative to the housing (10); a third coupling part (120) rotatably connected to the piston rod (60) and axially displaceable relative to the piston rod (60) and the housing (10), wherein the carpule holder (13) can be connected to or separated from the housing (10) by at least one rotational movement relative to the housing (10), the first coupling part (90) being rotated by the rotational movement, characterized in that the first and the second coupling part (90, 110) are coupled to one another with a cam gear, so that a rotation of the first coupling part (90) causes an axial displacement of the second coupling part (110), wherein the third coupling part (120) is rotatively coupled or decoupled from the drive sleeve (40) by the axial displacement. 2. Administering device (1) according to claim 1, characterized in that the cam mechanism by a guide groove (91) in one of the first or second coupling part (90, 110) and by a guide cam (111) on the other of the first or second coupling part (90 , 110) is formed. 3. administering device (1) according to claim 1 or 2, characterized in that the axial displacement of the second coupling part (110) causes an axial displacement of the third coupling part (120) relative to the piston rod (60), whereby the third coupling part (120) with the drive sleeve (40) is rotatively coupled or decoupled. 4. administering device (1) according to one of claims 1 to 3, characterized in that the second and the third coupling part (110, 120) are immovably connected to one another in the axial direction. 5. administering device (1) according to one of claims 1 to 4, characterized in that the first, the second and the third coupling part (90, 110, 120) are sleeve-shaped. 6. Administering device (1) according to one of claims 1 to 5, characterized in that the first coupling part (90) comprises an engagement element (92) which can engage in a counter-engagement element in the carpule holder (13) for the rotative coupling of the first coupling part (90 ) with the carpule holder (13). 7. administering device (1) according to any one of claims 1 to 6, characterized in that the first coupling part (90) is additionally mounted axially displaceable relative to the housing (10) and that the administering device (1) has an elastic element (85), by which the first coupling part (90) can be biased in a distal direction. 8. administering device (1) according to one of claims 1 to 7, characterized by a ratchet element (50) with ratchet arms (52) which are designed to cooperate with counter-elements (43) so that a rotation of the drive sleeve (40) relative to the housing (10) is possible in a first direction of rotation and is prevented in a second direction of rotation opposite to the first direction of rotation. 9. administering device (1) according to claim 8, characterized in that the ratchet element (50) is designed as a separate component. 10. administering device (1) according to claim 8, characterized in that the ratchet element (50) is held non-rotatably on the housing (10). 11. administering device (1) according to claim 9 or 10, characterized in that the ratchet element (50) is made essentially of a metallic material.