WO2013127876A1

WO2013127876A1 - Injection device with improved piston rod drive

Info

Publication number: WO2013127876A1
Application number: PCT/EP2013/053960
Authority: WO
Inventors: Markus Frantz
Original assignee: Tecpharma Licensing Ag
Priority date: 2012-02-29
Filing date: 2013-02-27
Publication date: 2013-09-06

Abstract

A drive mechanism is described which, among other things, has a gear unit (9) which is kinematically arranged between a drive element (5) and a guide element (7) and, on rotation of the drive element (5) relative to a housing (1), causes a movement of the guide element (7) relative to the housing (1) and to the drive element (5) by way of which a piston rod (6) is moved along the longitudinal axis thereof relative to the drive element (5) and/or to the guide element (7).

Description

Injection device with improved piston rod drive

The invention relates to an injection device for administering a liquid product, in particular a medicament, such as insulin for diabetes therapy. In particular, the invention relates to a drive mechanism for such an injection device.

From the prior art, such as WO 99/38554 AI, injection devices are known in which a threaded piston rod is rotated relative to a housing in rotation to a piston of a product container for the distribution of the product to move. The piston rod is in threaded engagement with the housing or with respect to the housing fixed member. Due to the threaded engagement, rotation of the piston rod causes it to be screwed in the dispensing direction and displace the piston. In order to set the piston rod in rotation, a drive member is rotated, which is axially fixed with respect to the housing and extending in parallel to the longitudinal direction of the piston rod, engages formed by the piston rod longitudinal guides.

From the prior art, such as US 5,104,380 A, an alternative to this solution is known in which the longitudinal guides of the piston rod are in engagement with the housing or with respect to the housing fixed member, whereby the piston rod with respect to the housing rotatably but axially displaceable. The drive member engages the threads of the piston rod, whereby rotation of the drive member fixed with respect to the housing causes the piston rod to be axially displaced with respect to the housing.

In another, known from the prior art, namely the WO 04/078239 AI known alternative, the piston rod has two different threads, one of which is in engagement with the housing or a housing-fixed member and the other is in engagement with a drive member , which in a product distribution with respect to the housing rotationally fixed, but axially displaceable. The thread of the threaded engagement between the drive member and the piston rod has a pitch that is large enough that no Self-locking between the drive member and piston rod is. The axial movement of the drive member relative to the housing causes the piston rod to rotate, thereby screwing in the dispensing direction due to threaded engagement with the housing or housing-fixed member.

It is an object of the invention to provide a drive mechanism for an injection device which allows an even finer distribution of the product dose.

The object is solved by the features of claim 1. Advantageous developments emerge from the dependent claims, the description and the figures.

The invention is based on a drive mechanism for an injection device for administering a liquid medicament. The drive mechanism has a housing. The housing is preferably sleeve-shaped and / or elongated.

The housing is intended to receive a piston rod drive. The housing can optionally accommodate a product container or even form the product container. The housing can be one or more parts. For example, the housing may form a proximal housing part which receives the piston rod drive. The housing may further include a product container holder, which holds the product container, such. B. a carpule, receives and is connected to the housing or the proximal housing part. This connection can be such that the product container holder and the housing or the proximal housing part after connection inseparable, that is only solvable by destruction of fasteners. Such a solution is particularly advantageous in disposable injection devices which are disposed of as a whole after the product contained in the product container is completely discharged. Alternatively, the product container holder can also be releasably secured to the housing, whereby it is possible to use the drive mechanism, if necessary, multiple times, that is to replace an empty product container with a filled product container. The housing preferably serves to be gripped by the user of the device. In particular, the housing may have a substantially cylindrical shape. The housing may, for. B. a pointing device, in particular a window, by means of which or by which a currently set dose, preferably from a scale of a dose setting element, can be read.

The drive mechanism further includes a piston rod having a longitudinal axis. The piston rod is movable along its longitudinal axis and relative to the housing in the discharge direction, in particular in the product container in order to move a slidably received in the product container piston for displacement of the product from the product container. The piston rod comprises a first thread, in particular external thread, which advantageously extends around the longitudinal axis, in particular winds. The first thread may have a pitch that is so large that self-locking or no self-locking occurs, especially when the piston rod is acted upon by a force acting along its longitudinal axis. The thread can be one or more continuous.

The piston rod further includes a guide in addition to the first thread. The guide may comprise a longitudinal guide, such as, for example, extending parallel to the longitudinal axis of the piston rod. in the form of a guide groove or a flattened flank. Alternatively, the guide may be a second thread, in particular different from the first thread, which has a different thread pitch than the first thread. The second thread may be an external thread and / or have a pitch which is so large that a self-locking or no self-locking occurs, in particular when the piston rod is acted upon by a force acting along its longitudinal axis.

If the guide is a second thread, it is preferred that it has a greater or smaller pitch than the first thread and / or an opposite or a same or similar direction of rotation as the first thread. If the guide is a second thread, it may be superimposed on the first thread. In particular, the first thread and the second thread or their threads can cross each other. This is z. B. possible if the first thread and the second thread the same direction of rotation, but different gradients exhibit. Furthermore, this is possible if the first thread and the second thread have different directions of rotation, such. B. a left-hand thread and a right-hand thread, wherein the second thread may have a larger, a same or a smaller pitch than the first thread. These thread pitch combinations are also useful when the first thread and the second thread do not overlap or cross over or the threads are overlay free. For example, the first thread and the second thread may be arranged at different positions relative to the longitudinal axis of the piston rod. For example, the second thread may be disposed proximal of the first thread, or vice versa. For example, one of the first thread and the second thread can be arranged in the region of the proximal end of the piston rod and the other of the first and second threads can be arranged in the region of the distal end of the piston rod. For example, arranged at different axial positions and / or separate first and second threads, the first or the second thread in a region of the piston rod may be arranged, which has a larger outer diameter than the region with the other thread. This area may preferably be formed at the proximal end of the piston rod.

The drive mechanism further comprises a piston rod drive comprising at least a drive member and a guide member. The drive member and / or the guide member may each be designed sleeve-shaped and / or preferably surround the piston rod. In particular, the drive member and the guide member may each be in contact with the piston rod.

The drive member and the guide member are in particular arranged to each other that between the drive member and the guide member, an axial movement is not possible and a rotational relative movement is possible. In other words, the drive member and the guide member are axially fixed relative to each other with respect to the longitudinal axis of the piston rod. For example, the drive member with the guide member in an engagement, in particular be snapped, which prevents movement of the drive member relative to the guide member along the longitudinal axis of the piston rod but allows a rotational movement between the drive member and guide member. In particular, that is Drive member and the guide member preferably arranged permanently fixed relative to each other axially both at a dose setting and during the dose distribution.

One of the drive member and guide member may be in a first engagement with the first thread and the other of the drive member and guide member may be in a second engagement with the guide of the piston rod. For example, the guide member with the first thread is in a first engagement and the drive member with the guide of the piston rod in a second engagement, or vice versa.

In particular, the drive member and / or the guide member may be arranged not displaceable relative to the housing in the longitudinal direction of the piston rod. In other words, the drive member and guide member are axially fixed both at a dose setting and during a dose release, preferably permanently relative to the housing. In particular, in the case of the dose distribution, the drive member and the guide member can perform rotational movements relative to the housing.

According to the invention, the drive mechanism to a transmission which is arranged kinematically between the drive member and the guide member. "Kinematically between" does not necessarily mean "geometrically between" but rather that the transmission converts or mediates movement of the drive member into movement of the guide member. Upon rotation of the drive member relative to the housing, the transmission may cause movement of the guide member relative to the housing and the drive member. In particular, the drive member rotates relative to the housing and relative to the guide member, wherein the guide member also moves relative to the housing and the drive member due to the action of the transmission. Due to the interaction of the drive member via the transmission with the guide member, the piston rod is moved along its longitudinal axis relative to the drive member and / or the guide member upon rotation of the drive member relative to the housing, in particular in the dispensing direction. The fact that both the drive member and the guide member rotate upon rotation of the drive member, an even finer distribution of the adjusted product dose compared to the devices of the prior art can be achieved, in particular to an even greater extent, if the guide is a second thread. By appropriate arrangement of the thread but also a coarser distribution can be achieved if this should be desired.

In particular, due to the first engagement, the second engagement, and the rotation of the drive member relative to the housing, the piston rod is moved along its longitudinal axis relative to the drive member and / or guide member, particularly in the dispensing direction and when a set product dose is to be dispensed.

Such a transmission can be realized by means of several designs. These embodiments have in common in common that the gear has at least one gear which is rotatable about an axis of rotation which is radially spaced from the longitudinal axis of the piston rod, or is rotated when the drive member is rotated relative to the housing. In particular, this gear may have an external toothing. The tooth forms for such gears are familiar to the expert.

In preferred embodiments, the at least one gear part of a planetary gear, such as. B. may be a planetary gear meshing with a ring gear and a sun gear. The planetary gear can roll, in particular with its circumference, both on the ring gear and on the sun gear. Planetary gears as such should be known in the art, the terms sun gear, ring gear, planetary gear and planet carrier Termini are technici.

In particular, the planetary gear can be arranged on a planet carrier and on a rotational axis spaced apart from the longitudinal axis of the piston rod, in particular a planetary gear axis of rotation. The Planetenraddrehachse is preferably stationary with respect to the planet carrier. For example, the planetary carrier or the planetary gear may form a planetary pin on which the planetary gear is rotatably arranged relative to the planetary carrier and which forms the Planetenraddrehachse. The planet carrier may be rotatable in certain embodiments about the longitudinal axis of the piston rod, which may thus also be referred to as a planet carrier rotation axis. In such embodiments, the planetary gear can rotate about two axes, namely about the axis on which it sits (Planetenraddrehachse) and about the longitudinal axis of the piston rod (planet carrier rotation axis). In versions where the planet carrier is rotationally fixed with respect to the housing, the planetary gear can rotate at least about the Planetenraddrehachse.

In particular, the planetary gear more than one planetary gear, such. B. have three or four planetary gears, which may be evenly distributed over the circumference of the sun gear in particular. The planet gears may preferably be arranged on a common planet carrier, d. h., That the Planetenraddrehachsen, on each of which sits at least one planetary gear, may be stationary relative to each other. Several planet wheels have the advantage of centering the sun gear radially and securing it against movement of the sun gear transverse to the longitudinal axis of the piston rod.

In a preferred embodiment, the planet carrier rotatably connected to the drive member, the ring gear rotatably connected to the housing and the sun gear rotatably connected to the guide member. This causes the drive member and the guide member to rotate in the same rotational direction when the drive member is rotated relative to the housing.

In a further embodiment, the planet carrier rotatably connected to the housing, the ring gear rotatably connected to the drive member and the sun gear rotatably connected to the guide member. This causes the drive member and the guide member to rotate in opposite directions of rotation when the drive member is rotated relative to the housing.

In yet another embodiment, the planet carrier rotatably connected to the housing, the ring gear rotatably connected to the guide member and the sun gear rotatably connected to the drive member. This ensures that the drive and the guide member rotate in opposite directions of rotation when the drive member is rotated relative to the housing.

In yet another embodiment, the planet carrier rotatably connected to the guide member, the ring gear rotatably connected to the housing and the sun gear rotatably connected to the drive member. This causes the Turn the drive and the guide member in the same direction of rotation when the drive member is rotated relative to the housing.

In yet another embodiment, the transmission may include a first gear having a first outer toothing and a first pitch circle diameter and a second gear having a second outer pitch and a second pitch circle diameter. The first pitch circle diameter is larger or smaller than the second pitch circle diameter. Due to the different Wälzkreisdurchmesser the first outer toothing rotates at a different angular velocity than the second outer toothing when the drive member is rotated relative to the housing. For example, the first gear and the second gear may be disposed on a common axis about which they are rotatable. Alternatively, the first gear and the second gear may be arranged on a common planet carrier, wherein the spaced apart from the longitudinal axis of the piston rod first axis of rotation of the first gear and spaced from the longitudinal axis of the piston rod second axis of rotation of the second gear in the circumferential direction or radially relative to the longitudinal axis relative can be offset from each other.

In particular, in this embodiment, the transmission having a ring gear with a first internal toothing and a second internal toothing, wherein the first outer toothing of the first gear meshes with the first internal toothing of the ring gear and wherein the second outer toothing of the second gear meshes with the second internal toothing of the ring gear.

The transmission may further include a first sun gear meshing with the first planetary gear and having a second sun gear meshing with the second planetary gear. The first sun can z. B. rotatably with the drive member and the second sun gear can, for. B. rotatably connected to the guide member. The first ring gear and the second ring gear can, for. B. be fixed to the housing.

In particular, the axis of rotation on which the first gear is arranged and the axis of rotation on which the second gear is arranged can rotate relative to the housing and about the longitudinal axis of the piston rod. It is advantageous if the first and second gears are arranged on a common planet carrier, wherein the first axis of rotation and the second axis of rotation need not necessarily coincide but may also be offset from each other.

In a further embodiment which does not require a ring gear, the at least one gear can have a first outer toothing with a pitch circle diameter and a second outer toothing with a second pitch circle diameter, wherein the first pitch circle diameter is greater or smaller than the second pitch circle diameter. The first outer toothing is preferably rotationally fixed relative to the second outer toothing, in particular permanently, d. H. also when the at least one gear and / or the drive member is rotated.

It is preferred that the rotational movement of the drive member is converted via the first outer toothing in a rotational movement of the at least one gear and this gear drives the guide member via its second outer toothing.

Preferably, the axis of rotation on which the at least one gear is arranged with respect to the housing fixed, d. h., That this axis of rotation can not rotate in particular about the longitudinal axis of the piston rod.

The drive mechanism has a dose setting mechanism in generally preferred embodiments. The dose setting mechanism may, for. B. be designed as described in WO 99/38554 to Figures 15 to 17. For example, the dose setting mechanism may include a non-self-locking Schaub connection along which an injection button in which a dose setting member, in particular, or the injection button itself is rotated relative to the housing and unscrewed from the proximal end of the housing to over this proximal end to overstep a distance determined by the angle of this rotation. Upon axial retraction of the injection button, the screwing movement converts this axial movement into a rotation of the drive member. In combination with the transmission according to the invention, the screwing movement also converts this axial movement into a rotation of the guide member. Alternatively, it is possible that the dose setting element is configured as indicated in EP 1 819 382 B1. Thus, the dose setting mechanism may comprise a dose setting member in the form of a dosing button axially fixed relative to the housing, which is rotated relative to the housing for dose adjustment. Rotation of the dose setting member relative to the housing causes rotation of a dose indicating drum relative to the housing. The dose indicating drum is threadable in the housing, in particular received by threaded engagement with the housing. As the dose setting knob rotates, the dose indicating drum is threaded along the housing with the dose to be administered displayed in a window of the housing. For the dose distribution, the dose display drum is screwed back to the value zero, while in the meantime the necessary rotational movement is transmitted in the drive mechanism according to the invention to the drive member, which in turn rotates relative to the housing.

Alternatively, or in addition to this embodiment, the drive mechanism may comprise a spring which is tensioned in the setting of the desired product dose and emits their spring energy to the drive member in the form of a rotation of the drive member for a product distribution. For this purpose, the drive mechanism on an operating knob, the actuation of which causes the energy stored in the spring is delivered to the drive member, whereby this is rotated relative to the housing.

In generally preferred embodiments, the drive mechanism may comprise a unidirectional clutch which permits rotation of the drive member or guide member in a rotational direction and locks in the opposite direction of rotation. In particular, the permissible direction of rotation may be that by means of which the piston rod is moved in the dispensing direction or distal direction of the drive mechanism. The unidirectional coupling can be designed as a ratchet z. B. is arranged between the housing and drive member.

In particular, the unidirectional coupling can be designed so that an initial resistance, which is set large enough to one by the dose setting on the Clutch acting torque must be overcome before a rotation takes place. Generally preferably, the dose setting mechanism is coupled to the drive member so as to prevent rotation of the drive member at the dose setting and to effect the dose distribution. In particular, z. Example, via a clutch, a dose display drum and the drive member for the distribution are rotationally determined, in particular by pressing an operating knob, which rotate the dose display drum and the drive member together, in particular are relatively rotatable relative to each other. The clutch may be open at the dose setting so that the drive member is rotationally decoupled from the dose indicating drum.

The drive mechanism may optionally include a mechanism for inhibiting the setting of a dose exceeding the amount of drug in the product container, wherein a dose is adjusted by rotation, particularly a dosing member or dose setting member or dosing knob of a dose setting mechanism. The mechanism may comprise a limiter, which is arranged kinematically between drive member and dosing member, in particular a dose display drum. The limiter and the drive member may be coupled such that relative rotation, particularly during dose adjustment, between the dose setting member and the drive member causes the limiter to move to a stop position in which the limiter inhibits the setting of a dose corresponding to the dose Amount of a product in the product container exceeds. Examples of correspondingly suitable limiters are disclosed in WO 2010/149209 or in WO 01/19434 A1, in particular in FIG.

The invention has been described with reference to several advantageous embodiments. In the following, advantageous embodiments will be described with reference to figures. The disclosed features form the subject matter of claim 1 in particular individually and in any combination with the claims or / and the foregoing description advantageous further. Show it:

Figures la-lc an injection device of the prior art, namely from the

FIGS. 15 to 17 of WO 99/38554 A1,

FIG. 2 shows a first embodiment of a drive mechanism according to the invention, FIG. 3 shows a second embodiment of a device according to the invention

Drive mechanism,

Figure 4 shows a third embodiment of an inventive

Drive mechanism,

Figure 5 shows a fourth embodiment of an inventive

Drive mechanism,

Figure 6 shows a fifth embodiment of an inventive

Drive mechanism,

Figure 7 shows a sixth embodiment of an inventive

Drive mechanism,

Figure 8 is a piston rod for the invention described herein

Embodiments,

Figure 9 shows an alternative piston rod for the embodiments of the invention described herein.

In the figures 2 to 7 each embodiments of a drive mechanism are shown, which have preferred embodiments of a piston rod drive. Such a piston rod drive can be integrated into the device from FIGS. 1 a to 1 c. In the known from the prior art device of the figures la to lc is a manually operable injection device.

The device comprises a dose setting mechanism, which is at least one dosing member 2 in the form of a Dosierknopfs, in particular rotationally and axially fixed to a dose display drum 21 is connected. The dosing member 2 is for adjusting the product dose to be administered with respect to a housing 1 rotatable, in particular screwed. To increase the dosage, the dosing member 2 is unscrewed from the proximal end of the housing 1. To reduce the dosage, the dosing member 2 is screwed back into the housing 1. In general, it can be stated that the dosing member 2 can be screwed back and forth relative to the housing 1 for setting the dose. For the screwing movement, the dosing member 2, in particular the dose-indicating drum 21, has a thread which is in engagement with a thread of the housing 1. The thread pitch is such that no Self-locking occurs when the dosing member 2 is loaded or operated with a force acting in the ejection direction.

The housing 1 has a window 14 in which the product dose set by the dose setting mechanism is displayed. The dose display drum 21 has on its outer periphery a scale with the various adjustable product cans, which extends helically in accordance with the thread pitch of the thread 11. For the dose setting, a portion of the scale, namely the scale value corresponding to the desired product dose, is displayed in window 14.

The injection device from the figures la to lc further comprises a first coupling member 3, which is non-rotatably, but axially displaceably connected to a drive member 5. Such a connection can be z. B. by means of a groove extending along the longitudinal axis of the injection device realize.

The particular sleeve-shaped first coupling member 3 has a toothing 31, which rests in a toothing 22 which is formed on the dosing member 2. At a dose setting, the first coupling member 3 is rotationally fixed with respect to the housing 1. In this case, the toothing 22 is rotated relative to the toothing 31. The toothing 22 and the toothing 31 form an axial coupling. For dose distribution, a trained at the proximal end of the device actuator button 4 is pressed, in particular with the thumb of the user's hand, which surrounds the housing 1. The thereby acting in the distal direction of the user force on the actuator button 4 is transmitted to the toothing 31, which is pressed into the toothing 22, whereby the dosing member 2 and the first coupling member 3 are rotatably coupled relative to each other. By pressing the actuating button 4 and the non-self-locking thread 11, the dosing member 2 is screwed back into the housing 1. By rotationally fixed during actuation connection between the dosing member 2 and the first coupling member 3, the first coupling member 3 is rotated relative to the housing 1. The coupling member 3 takes with the drive member 5, which also rotates. The drive mechanisms according to the invention can be combined not only with the device shown in Figures la to lc, but in principle with any device in which an actuation of the drive mechanism for a product distribution causes rotation of the drive member 5. If the drive mechanism is provided with a dose setting mechanism, it is preferable that the drive member 5 is not rotated in the dose setting movements of the dose setting mechanism relative to the housing 1. In particular, a rotation of the drive member 5 can take place only when operating the drive mechanism for a product distribution.

The invention can also be advantageous z. B. in devices such as those used in US 5,104,380 A, WO 2007/017052 AI. In these devices, the drive energy is not provided manually deviating from the device of Figures la to lc, but by a spring which is either stretched or stretched at a dose setting and is connected to the drive member 5 that the or at least a part of stored spring energy upon actuation of an actuating element or operating knob 4, the drive member 5 rotates or rotates for the product distribution. This type of device also allows for combination with a dose indicating drum 21. The spring may preferably be a torsion or torsion spring.

The drive mechanisms according to the invention shown in Figures 2 to 7 have as essential features a piston rod 6, and a piston rod drive comprising a drive member 5 and a guide member 7, on. Furthermore, the drive mechanism comprises a gear which is arranged kinematically between the drive member 5 and the guide member 7.

The particular sleeve-shaped drive member 5 is rotatable relative to the housing 1 and preferably axially fixed. The drive mechanism is configured such that the drive member

5 upon actuation of the product discharge drive mechanism relative to the housing 1, particularly about the longitudinal axis of the drive mechanism or the piston rod

6 is turned. In an optional dose setting, the drive member 5 is not rotated relative to the housing 1 or the drive member 5 is rotatably relative to the housing 1. Preferably, the drive member 5 is arranged in the housing 1, that it is movable only in a single direction of rotation, that is not rotatable in the opposite direction of rotation. For this purpose, the drive mechanism may have a unidirectional clutch 52, the z. B. is designed as a ratchet. The unidirectional clutch 52 may, for. B. between the housing 1 and the drive member 5 act. For example, the drive member 5 may comprise an arm or ratchet arm for forming the unidirectional clutch 52, which in a circumferentially extending toothing of the housing 1 or a housing-fixed insert, as it is z. B. from the figures la and lb, engages.

For the drive mechanism from FIGS. 2 to 7, a piston rod 6 according to FIGS. 8 or 9 or from FIG. 1c can be used. Although a solid rod is shown, it may also be formed as a sleeve, i. H. it does not necessarily have to be massive.

The drive mechanism of Figures 2 to 7 further comprises a guide member 7 which is rotatable for a product discharge relative to the housing 1. The guide member 7 is further axially fixed relative to the housing 1. In this example, the guide member 7, as best seen in Figures 2 and 3, axially fixed to the drive member 5, in particular snapped axially fixed to the drive member 5. The connection between the guide member 7 and the drive member 5 is such that the guide member 7 is rotatable relative to the drive member 5.

The drive member 5 and the guide member 7 are thus axially fixed with respect to the housing 1, in particular regardless of whether a dose setting or dose distribution takes place.

The drive member 5 and the guide member 7 are respectively in engagement with the piston rod 6. In the figures 2 to 7 not all possibilities of engagement are indicated. In the figures 2 to 7 in particular the following interventions can be realized: When using a piston rod 6 according to Figure lc, the guide member 7 can engage in the guide 62 engaging the longitudinal guide 62 of the piston rod 6, wherein the drive member 5 in the first thread 61 having a pitch which is self-locking or not self-locking engages.

- The reverse case is possible, d. h., That the guide member 7 in the first thread 61, which may be self-locking or non-self-locking, engages, wherein the drive member 5 engages in the longitudinal guide 62.

The interventions of the drive member 5 and the guide member 7 in the piston rod 6 can also be such that the piston rod 6 is rotatable relative to the drive member 5 and the guide 7. For this purpose, as can be seen from the piston rods 6 of FIGS. 8 and 9, the guide member 7 engages in a first thread 61 and the drive member 5 in a second thread 63.

The second thread 63 is opposite to the first thread 61 in the piston rods 6 of Figures 8 and 9 from the direction of rotation ago. Since the threads 61, 63 are in opposite directions, the thread pitches can be different in magnitude but basically also the same size. Preferably, at least one of the threads 61, 63 of the slope ago so large that no self-locking occurs.

- Alternatively, the threads 61, 63 have the same direction of rotation, in which case they should then have different thread pitches from the amount.

In Figure 8, the first thread 61 is provided for engagement with the guide member 7 and distally of the second thread 63, which is provided for engagement with the drive member 5, respectively. In particular, the piston rod 6, where the second thread 63 is arranged, have a larger outer diameter than where the first thread 61 is arranged. In the example of FIG. 8, the second thread 63 is formed on an outer diameter enlarged portion located at the proximal end of the piston rod 6. In the piston rod 6 of Figure 9, the first thread 61 and the second thread 63 are superimposed, that is arranged at the same axial positions. Here, the threads 61, 63 intersect. The first thread 61 may be provided for engagement with the guide member 7 and the second thread 63 may be provided for engagement with the drive member 5, or vice versa.

The drive mechanisms according to the invention from FIGS. 2 to 7 have a common transmission, which is arranged kinematically between the drive member 5 and the guide member 7. The transmission is arranged to cause movement of the guide member 7 relative to the housing 1 and the drive member 5 upon rotation of the drive member 5 relative to the housing 1, particularly during or during dose distribution upon actuation of the drive mechanism. Due to the interventions of the drive member 5 and the guide member 7 with the piston rod 6 and the relative rotation between the drive member 5 and the guide member 7, the piston rod 6 is moved along its longitudinal axis relative to the drive member 5 and the guide member 7, in particular also relative to the housing first In this movement, the piston rod 6 is displaced or moved into the product container 8 and / or pressed against the piston slidably received in the product container 8, which is then moved relative to the product container 8 in the distal direction and the product contained in the product container 8 from the product container 8 displaced.

Due to the fact that the unidirectional clutch 52 no longer acts as shown in FIGS. 1 a to 1 c between the insert, which is in engagement with the thread 61 of the piston rod 6, but acts between the housing 1 and the drive member 5 , the guide member 7 shown in Figures 2 to 7 may be rotatable relative to the housing 1, resulting in the advantages described herein.

The transmission of Figures 2 to 6 are based on at least one planetary gear. The transmission of Figure 7 comes without planetary gear.

A planetary gear generally comprises a sun gear 93, a ring gear 94, and a planetary gear 95 disposed between ring gear 94 and sun gear 93, which are connected via its Outer periphery has a toothing which is in engagement with the toothing of the ring gear 94 and the sun gear 93. The planetary gear has at least one planetary gear 95, although it is preferred that over the circumference of several planet gears 95, such. B. two, three or four planetary gears 95 are arranged in particular evenly distributed. In the figures 2 to 6 z. B. four planetary gears arranged over the circumference, but only two of which are visible.

In the following, only one planetary gear is used, this analogously applying to the other planetary gears 95 of the planetary gear. The planetary gear 95 is disposed on a Planetenraddrehachse about which it is rotatable and which is spaced from the longitudinal axis of the piston rod 6. Further, the planetary gear 95 is disposed on a planet carrier 91. At the planet carrier 91, the other planet gears 95 of the planetary gear are preferably arranged. In the examples shown, the planetary gear axis 95 of the planetary gear 95, which is spaced from the longitudinal axis of the piston rod 6, is formed by a carrier pin which is arranged on the planet carrier 91 and / or can be integral with the planet carrier 91. However, alternatively, the planetary gear 95 may form the support pin 92 itself, wherein the support pin 92 z. B. can be rotatably mounted on the planet carrier 91.

In the example of Figure 2, the ring gear 94 is fixed to the housing, i. H. formed axially and rotationally fixed to the housing 1 connected insert. The sun gear 93 is rotatably connected to the guide member 7, in particular in one piece with the guide member 7. The planet carrier 91 is rotatably connected to the drive member 5, in particular in one piece with the drive member. 5

Upon rotation of the drive member 5 relative to the housing 1, the planetary gear 95 is rotated about the longitudinal axis of the piston rod 6, which may also be referred to as a planet carrier rotation axis, and about the Planetenraddrehachse on which it is arranged. In this case, the planetary gear 95 rolls on the ring gear 94, whereby the sun gear 93 or the guide member 7 is rotated relative to the housing 1 and the drive member 5. With respect to the housing 1, the drive member 5 and the guide 7 rotate in the same direction of rotation, wherein relative to the housing 1, the guide member 7 rotates at a magnitude higher angular velocity than the drive member. 5

In the embodiment of Figure 3, the ring gear 94 is rotatably connected to the drive member 5, in particular in one piece with the drive member 5. The sun gear 93 is rotatably connected to the guide member 7, in particular integrally with the guide member 7. The planet carrier 91 is fixed to the housing, d. H. rotatably and axially connected to the housing 1.

Upon rotation of the drive member 5, the ring gear 94 rolls on the planetary gear 95, which is about its Planetenraddrehachse on which it is fixed with respect to the housing 1 rotates, whereby the sun gear 93 or the guide member 7 relative to the housing 1 and the drive member 5 is rotated. With respect to the housing 1, the drive member 5 and the guide member 7 rotate in opposite directions of rotation. Relative to the housing 1, the guide member 7 can rotate with a magnitude higher angular velocity than the drive member. 5

In the embodiment of Figure 4, the sun gear 93 is rotatably connected to the drive member 5, in particular integrally with the drive member 5. The planetary gear 94 is rotatably connected to the guide member 7, in particular in one piece with the guide member 7. The planet carrier 91 is - similar to the embodiment of Figure 3 - fixed to the housing. Upon rotation of the drive member 5, the sun gear 93 rolls on the planetary gear 95, whereby the ring gear 94 is rotated relative to the drive member 5 and the housing 1. With respect to the housing 1, the drive member 5 and the guide member 7 rotate in opposite directions of rotation. Relative to the housing 1, the guide member 7 can rotate in terms of amount at a lower angular velocity than the drive member. 5

In the embodiment of Figure 5, the drive member 5 is rotatably connected to the sun gear 93, in particular in one piece with the sun gear 93. The ring gear 94 is fixed to the housing, ie relative to the housing 1 axially and rotationally fixed. The planet carrier 91 is rotatably connected to the guide member 7, in particular in one piece with the guide member. 7 Upon rotation of the drive member 5 relative to the housing 1, the sun gear 93 rolls on the planetary gear 95, which in turn rolls on the ring gear 94, whereby the planet carrier 91 or the guide member 7 relative to the housing 1 and the drive member 5 in particular about the longitudinal axis of Piston rod 6 is rotated. Relative to the housing 1, the drive member 5 and the guide member 7 rotate in the same direction of rotation and the guide member 7 rotates at a lower angular velocity than the drive member. 5

FIG. 6 shows an embodiment of the drive mechanism according to the invention, which in the narrower sense has two planetary gears. In this case, the parts of the first planetary gear with the reference numerals used with reference to "a" and the parts of the second planetary gear with the suffix "b" are used. The planetary gear 95 a and the planetary gear 95 b are arranged here on a common planet carrier. In the example shown, the planetary gear axis of rotation on which the first planetary gear 95a is disposed and the planetary gear axis on which the second planetary gear 95b is disposed have a common axis of rotation formed by the support pin 92 and at the same time constitute the planetary carrier. The first planetary gear 95a and the second planetary gear 95b are rotatable relative to each other. Alternatively, the first planetary gear 95a and the second planetary gear 95b may be circumferentially and / or radially offset with respect to the longitudinal axis of the piston rod 6, particularly the planetary gear axes of the planetary gears 95a, 95b. Preferably, the planet gears 95a, 95b still sit on a common planet carrier.

The first sun gear 93 a is rotatably connected to the drive member 5, in particular in one piece with the drive member 5. The second sun gear 93 b is rotatably connected to the guide member 7, in particular in one piece with the guide member 7. The first ring gear 94 a and the second ring gear 94 b respectively fixed to the housing, in particular rotationally and axially connected to the housing 1. The ring gears 94a, 94b together form a one-piece insert, which may be referred to generally as ring gear 94. The first planetary gear 95a and the second planetary gear 95b may basically have the same diameter, in particular pitch circle diameter. If the Planetenraddrehachsen the first and second planetary gears 95a, 95b radially equidistant from the longitudinal axis of the piston rod 6, the drive member 5 and the Guide member 7 at the same angular velocity and rotate the same direction. Thus, the guide member 7 and the drive member 5 can rotate relative to each other, in the case of the same pitch circle diameter of the first and second planetary gears 95a, 95b, the Planetenraddrehachsen the planetary gears 95a, 95b be spaced differently radially from the axis of rotation of the piston rod 6. However, a radially different distance also allows that the pitch circle diameter of the first planetary gear 95a and the pitch circle diameter of the second planetary gear 95b are of different sizes. However, this is not shown in FIG.

In FIG. 6, the first and second planetary gears 95a, 95b are equally spaced radially from the longitudinal axis of the piston rod 6, so that they should have different pitch circle diameters. In the example shown, the pitch circle diameter of the first planetary gear 95a is larger than the pitch circle diameter of the second planetary gear 95b. But it is also the reverse arrangement possible, namely that the first planetary gear 95 a has a smaller pitch circle diameter than the second planetary gear 95 b.

Upon rotation of the drive member 5, the first sun gear 93a rolls on the first planetary 95a, which rolls on the first ring gear 94a. In this case, the common planet carrier or the support pin 92 is rotated about the longitudinal axis of the piston rod 6 relative to the housing 1. The planetary carrier or the trunnion 92 carries the second planetary gear 95b, which rolls on the second ring gear 94b, whereby the second sun gear 93b or the guide member 7 is rotated relative to the housing 1 and the drive member 5. With respect to the housing 1, the drive member 5 and the guide member 7 rotate in the same direction of rotation. In the example shown in Figure 6, the guide member 7 rotates with respect to the housing at a lower angular velocity than the drive member 5. If the pitch circle diameter of the second planetary gear 95b greater than that of the first planetary gear 95 a, the guide member 7 would relative to the Housing 1 rotate at a higher angular velocity than the drive member. 5 Regardless of which of the first and second planetary gears 95a, 95b has the larger pitch circle diameter, in the embodiment of FIG. 6 the second ring gear 94b, which is preferably present for stability reasons, can be omitted.

In the embodiment of FIG. 7, at least one, preferably several, in particular two, three or four toothed wheels 97 are provided. In the following, only one gear 97 will be described, the explanations for this apply mutatis mutandis to the other gears 97. The gear 97 has a first toothing 97a and a second toothing 97b, wherein the first toothing 97a has a larger pitch circle diameter than the second toothing 97b. The first toothing 97a and the second toothing 97b are rotatable relative to each other, in particular integrally connected to each other. The gear 97 is seated on an axis of rotation which is arranged radially spaced from the axis of rotation of the piston rod 6. The axis of rotation is formed by a support pin 96 which is fixed to the housing, in particular rotationally and axially fixed with respect to the housing 1. The support pin 96 is formed on an insert, which is snapped with the housing 1 in the example shown. Alternatively, this insert could also be glued or welded to the housing 1. An external toothing is rotatably connected to the drive member 5, in particular integrally formed on the drive member 5. The toothing meshes with the first toothing 97a of the toothed wheel 97. The guide member 7, which is rotatable but axially fixed relative to the drive member 5, in particular connected thereto, is non-rotatably connected to a toothing which meshes with the second toothing 97b. In the example shown, the toothing is integrally formed by the guide member 7. Upon rotation of the drive member 5 relative to the housing 1, the teeth of the drive member 5 roll on the first teeth 97a, whereby the gear 97 is rotated relative to the housing 1 and wherein the guide member 7 is rotated relative to the housing 1 and the drive member 5 , In the example shown in Figure 7, drive member 5 and guide member 7 rotate relative to the housing 1 in the same direction of rotation. With respect to the housing 1, the drive member 5 rotates at a higher angular velocity than the guide member 7. Conversely, namely, if the teeth 97a has a smaller pitch circle diameter than the teeth 97b, the drive member 5 would with respect to the housing 1 with a turn greater angular velocity than the guide member. 7 LIST OF REFERENCE NUMBERS

Housing 6 piston rod

Thread 61 first thread

Wall 62 longitudinal guide

Product container receptacle 63 second thread

Window 64 flange

Dosing member 7 guide member

Dose display drum 71 Use

first coupling structure /

Gearing 8 product container

Coupling member 9 Transmission second coupling structure / 91 planet carrier

Gearing 92 Supporting pin annular projection 93 Sun gear

Ratchet arm 94 ring gear

Engaging member 94a first ring gear

94b second ring gear

Actuation knob 95 planetary gear

Connecting portion 95a first planetary gear

95b second planetary gear

drive member

Engagement counterpart 96 Trunnion unidirectional clutch / 97 gear

Ratchet arm 97a first toothing

97b second toothing

Claims

claims

A drive mechanism for an injection device for administering a liquid product or medicament, comprising:

a) a housing (1),

b) a piston rod (6) having a longitudinal axis, a first thread (61) extending about the longitudinal axis, and a guide (62; 63) in addition to the first thread (61), the guide (62; 63) extending along the longitudinal axis of the piston rod (6) extending longitudinal guide (62) or a second thread (63) which has a different thread pitch than the first thread (61) may be, c) a piston rod drive, comprising the following elements:

a drive member (5),

a guide member (7), wherein between the drive member (5) and the guide member (7) an axial movement is not possible and a rotational relative movement is possible,

d) wherein one of the drive member (5) and guide member (7) with the first thread (61) in a first engagement and the other of drive member (5) and guide member (7) with the guide (62; 63) of the piston rod ( 6) is in a second engagement, characterized in that

e) the drive mechanism comprises a gear (9) which is kinematically arranged between the drive member (5) and the guide member (7) and relative to the housing (1) relative to the housing (1) movement of the guide member (7) relative to rotation of the drive member (5) to the housing (1) and the drive member (5), whereby the piston rod (6) along its longitudinal axis relative to the drive member (5) and / or the guide member (7) is moved.

2. Drive mechanism according to claim 1, characterized in that due to the first engagement, the second engagement and the rotation of the drive member (5) relative to the housing (1), the piston rod (6) along its longitudinal axis relative to the drive member (5) and / or the guide member (7) is moved.

3. Drive mechanism according to one of the preceding claims, characterized in that the transmission (9) at least one gear (95; 97) which is rotatable about an axis of rotation which is radially spaced from the longitudinal axis of the piston rod (6), or rotated becomes when the drive member (5) is rotated relative to the housing (1).

4. Drive mechanism according to one of the preceding claims, characterized in that the at least one gear (95; 97) is a planetary gear (95; 95a, 95b) of a planetary gear meshing with a ring gear (94) and a sun gear (93).

5. Drive mechanism according to the preceding claim, characterized in that

- The planet carrier (91) rotationally fixed to the drive member (5) is connected,

- The ring gear (94) rotatably connected to the housing (1) is connected and

- The sun gear (93) rotatably connected to the guide member (7) is connected,

- And in particular that the drive member (5) and the guide member (7) rotate in the same direction of rotation when the drive member (5) is rotated relative to the housing (1).

6. Drive mechanism according to claim 4, characterized in that

- The planet carrier (91) rotationally fixed to the housing (1) is connected,

- The ring gear (94) rotatably connected to the drive member (5) is connected and

- The sun gear (93) rotatably connected to the guide member (7) is connected,

- And in particular that the drive member (5) and the guide member (7) rotate in opposite directions of rotation when the drive member (5) is rotated relative to the housing (1).

7. Drive mechanism according to claim 4, characterized in that

- The planet carrier (91) rotationally fixed to the housing (1) is connected,

- The ring gear (94) rotatably connected to the guide member (7) is connected and

- The sun gear (93) rotationally fixed to the drive member (5) is connected, - And in particular that the drive member (5) and the guide member (7) rotate in opposite directions of rotation when the drive member (5) is rotated relative to the housing (1).

8. Drive mechanism according to claim 4, characterized in that

- The planet carrier (91) rotatably connected to the guide member (7) is connected,

- The ring gear (94) rotatably connected to the housing (1) is connected and

- The sun gear (93) rotationally fixed to the drive member (5) is connected,

9. Drive mechanism according to one of claims 1 to 4, characterized in that the transmission (9) comprises a first gear (95 a) having a first outer toothing and a first pitch circle diameter and a second gear (95 b) having a second outer toothing and a second pitch circle diameter wherein the first pitch circle diameter is larger or smaller than the second pitch circle diameter, wherein the first outer gear rotates at a different angular velocity than the second outer gear when the drive member (5) is rotated, the first gear (95a) and the second gear (95b) are arranged, for example, on a common axis about which they are rotatable.

10. Drive mechanism according to the preceding claim, characterized in that the transmission (9) has a ring gear (94) with a first internal toothing (94 a) and a second internal toothing (94 b), wherein the first external toothing of the first gear (95 a) the first internal toothing (95 a) of the ring gear (94) meshes and wherein the second external toothing of the second gear (95 b) with the second internal toothing of the ring gear (94 b) meshes.

11. Drive mechanism according to one of the two preceding claims, characterized in that the axis of rotation, on which the first gear (95 a) is arranged, and the rotation axis on which the second gear (95b) is disposed rotates relative to the housing (1) and about the longitudinal axis of the piston rod (6).

12. Drive mechanism according to one of the preceding claims, characterized in that the at least one gear (95; 97) has a first external toothing with a first pitch circle diameter and a second outer toothing with a second pitch circle diameter, wherein the first pitch circle diameter is larger or smaller than the second pitch circle diameter wherein the first outer toothing is rotationally fixed relative to the second outer tooth when the at least one gear (95; 97) is rotated.

13. Drive mechanism according to the preceding claim, characterized in that the rotational movement of the drive member (5) via the first external toothing in a rotational movement of the at least one gear (95; 97) is converted and this gear (95; 97) via its second external toothing Guide member (7) drives.

14. Drive mechanism according to one of the two preceding claims, characterized in that the axis of rotation, on which the at least one gear (95; 97) is arranged, with respect to the housing (1) is stationary.

15. Drive mechanism according to one of the preceding claims, characterized in that the guide (62; 63) is a second thread (63) having a pitch greater or smaller than the first thread (61) and / or an opposite or a same direction of rotation as or as the first thread (61).

16. Drive mechanism according to one of the preceding claims, characterized in that the guide (62; 63) is a second thread (63) which is superimposed or not superimposed on the first thread (61) or which relates to the longitudinal axis of the piston rod (6 ) is disposed at a different position than the first thread (61).

17. Drive mechanism according to one of the preceding claims, characterized in that the drive member (5) and / or the guide member (7) relative to the housing (1) in the longitudinal direction of the piston rod (6) are not arranged displaceably.

18. Drive mechanism according to one of the preceding claims, characterized in that the dose setting mechanism comprises a non-self-locking screw connection, along which a dose setting member (2) is rotated relative to the housing, and unscrewed from the proximal end of the housing (1) extending beyond this proximal end by a distance determined by the angle of rotation, wherein upon axial retraction of the dose setting member (2), the screwing action converts this axial movement into rotation of the drive member (5) and / or the guide member (7).

19. Drive mechanism according to one of the preceding claims, characterized by a unidirectional coupling (52) which permits rotation of the drive member (5) or the guide member (7) in a rotational direction and locks in the opposite direction of rotation, wherein the permissible direction of rotation is that by means of which the piston rod (6) is displaceable in the distal direction of the drive mechanism.

A drive mechanism according to the preceding claim, characterized in that the unidirectional clutch (52) is adapted to overcome an initial resistance set high enough to withstand a torque applied by the dose setting on the clutch (52) must before a rotation of the drive member (5) takes place.