INJECTION DEVICE FOR ADMINISTERING OR TRANSFERRING FLUID PRODUCT

Description

[0001] The present invention relates to an injection device, in particular to an injection device with a dosing device with which a dose or amount of a substance to be dispensed from or with the aid of the injection device can be adjusted.

[0002] Various injection devices are known from the prior art, in particular pin- or pen-shaped injection devices. WO93 / 07922 A1 shows such a pin- or pen-shaped injection device. The pen comprises a dosing device and a delivery mechanism, which are coupled to one another via a two-part one-way slip clutch 20 / 21. The coupling is achieved by intermeshing asymmetrical toothings, with the coupling engagement being assisted by a spring. A clutch input member 20 has a toothing pointing axially in the distal direction. A clutch output member 21 has a toothing complementary to the toothing. The two clutch members are arranged coaxially to the longitudinal axis of the pen and are designed to be rotatable relative to the housing of the pen. The individual teeth of the toothings have two flanks, with the two flanks having different pitches.One flank faces in the axial direction, and the second flank is inclined relative to the longitudinal axis. The axially aligned flanks prevent relative rotation between the clutch input member 20 and the clutch output member 21 in one direction during clutch engagement, while the second, inclined flanks allow relative rotation in the opposite direction.

[0003] To set the dose to be administered, the dosage knob 14 of the dosage device, together with the dosage sleeve 15, is unscrewed from the device housing. The coupling input member 20 is arranged in a manner that prevents rotation relative to the dosage knob 14, and the coupling output member 21 is arranged in a manner that prevents rotation relative to the delivery device. When increasing the dose, the pen is designed so that a relative rotation can occur between the coupling input member 20 and the coupling output member 21. The inclined flanks of the coupling teeth slide over each other, with the coupling input member 20 being moved axially against the spring force. When the tooth tips are exceeded, the coupling input member 20 springs back along the axially aligned flanks to its axial starting position and produces an audible click.If the dosing button 14 is screwed back into the housing, the one-way slip clutch prevents relative rotation between the dosing device and the conveyor mechanism due to the axially aligned tooth flanks on the coupling members 20, 21, whereby the rotation of the dosing button is thus passed on to the conveyor mechanism, allowing product to be dispensed from the pen. To correct the dose, the coupling engagement between the coupling members 20, 21 must be released manually and against the spring force. Once the coupling engagement is released, the dosing device can be moved back to its original position independently of the conveyor mechanism. This type of dose correction requires skill and strength from the user because both hands are needed to release the coupling engagement and keep it released, i.e. against the spring force. Once released, the dosing sleeve must then also be screwed back.When screwing back the dosing sleeve, there is no clicking noise as feedback for the user when the coupling is released.

[0004] EP1003581 B1 also shows a pen-shaped injection device in Figures 15 to 17. This injection device has a two-way slip clutch between the dosing device and the delivery device. The dosing device comprises a dosing sleeve 80 with a dosing button 81 arranged on the sleeve. The dosing sleeve 80 can be coupled to the driver tube 85 of the delivery device via the bushing 82. The clutch consists of a clutch input member (not shown) that is fixedly arranged on the dosing sleeve 80 and a clutch output member 93, referred to as a rosette, which is fixedly attached to the bushing 82. The clutch is closed by pressing the dispensing button 88 in the distal direction and is not positively engaged as long as the dispensing button is not actuated.The clutch input and output links have teeth that generally allow relative rotation, even when the clutch links touch each other due to weight forces. As long as the clutch is not closed by pressing the dispensing button, this allows a dosing movement for adding more fluid and for adjusting the dose. In the current state-of-the-art design, the two-way slip clutch does not produce a clicking sound, so a click function must be installed additionally and at a different location in the device.

[0005] EP 1218042 B1 discloses an injection pen with a drive sleeve having saw teeth arranged circumferentially on an outer side, which interact with ratchet arms of a dosing sleeve to generate a clicking sound when the dosing sleeve is rotated relative to the drive sleeve to set a dose. To dispense, the user presses a dispensing button distally, whereby axial teeth of the dosing sleeve are coupled with axial, front-side teeth on the drive sleeve, so that the drive sleeve rotates together with the dosing sleeve and can thereby move the piston rod in the dispensing direction.

[0006] It is an object of the present invention to provide an injection device of the type mentioned, ie an administration device with a dosing device and a conveying device which can be detachably coupled to one another via a coupling mechanism, which is of simple construction and gives the user improved perceptible feedback when setting the dose and correcting doses which are set too high.

[0007] This problem is solved by the subject matter having the features of claim 1.

[0008] Further advantageous embodiments emerge from the dependent claims. Description of the invention

[0009] In the context of this description of a generally pen-shaped injection device, various directional and positional specifications are made, which are briefly explained here. Axial orientation refers to orientation along the longitudinal axis of the injection device. Distal refers to the end of the injection device to which the injection needle is attached. Proximal, in turn, refers to the opposite end of the injection device. In the distal direction, it means looking in the direction of the distal end, and in the proximal direction, analogously, it means looking in the direction of the proximal end.

[0010] The invention relates to an improved injection device for administering a fluid product. The injection device comprises a housing with a receptacle for the product, a conveying device for conveying the product, and a dosing device for setting a product dose to be administered and for displaying the set product dose. The housing forms a receptacle for the product, preferably a receptacle for a container filled with the product. This container can preferably be a carpule. The conveying device comprises a piston rod which is movable relative to the housing in a conveying direction in order to dispense a set product dose in a conveying stroke corresponding to the set product dose. The conveying stroke is a translational movement of the piston rod, preferably a linear sliding movement.In a preferred embodiment, a movable piston of the container designed as a carpule is displaced during the conveying stroke. The conveying device further comprises a guide element which guides the translational movement of the piston rod. In a preferred embodiment, the guide element is designed as a longitudinal guide for the piston rod which is fixed to the housing, so that the piston rod can be axially displaced relative to the guide element, but cannot be rotated. The conveying device further comprises a drive element which engages with the piston rod. In a preferred embodiment, the drive element is designed as a threaded nut whose internal thread is engaged with a corresponding external thread on the outer surface of the piston rod. The threaded nut is preferably rotatable in the housing but axially fixed.In one possible preferred embodiment, the following kinematic arrangement results for the conveying mechanism of the conveying device: a rotation of the axially fixed threaded nut relative to the piston rod results in an axial movement of the piston rod, since the piston rod cannot rotate relative to the housing via the longitudinal guide. In other, equally preferred embodiments, the kinematic arrangement can also be inverted. This is achieved via a so-called kinematic reversal, whereby the threaded nut is fixed rotatably to the housing and the longitudinal guide is mounted rotatably and, if necessary, displaceably to the housing. If the longitudinal guide is rotated during this kinematic reversal, the piston rod screws through the thread of the threaded nut, which in this case is fixed relative to the housing.

[0011] The dosing device of the injection device comprises a dose setting element, preferably a dosing sleeve, which is threadedly engaged with the inside of the housing. A grippable element is attached to the proximal end of the dose setting element, which allows the user to set the desired dose. The dose setting element preferably performs a screwing movement out of the injection device when increasing the dose to be administered. To administer the set dose, or to reduce any dose that may have been set too high, the dose setting element can then be screwed back into the injection device. In a further preferred embodiment, there is a non-self-locking threaded connection between the housing and the dose setting element, which is designed as a dosing sleeve, so that the dosing sleeve can be screwed back into the injection device by applying axial forces.

[0012] The dosing device further comprises a coupling device that can operatively connect the dosing device to the conveying device. The coupling device is designed such that the setting and / or correction of a dose to be administered can occur independently of the conveying device, and such that, upon administration of a dose, the dosing device can be selectively operatively coupled to the conveying device such that a movement of the dosing device is transmitted in whole or in part to the conveying device. For example, only the rotational component of a screwing movement of a dosing sleeve can be transmitted to the conveying device, or alternatively, only the axial displacement. In one embodiment, the coupling device comprises a coupling sleeve with a coupling surface, wherein the coupling surface has engagement elements.The dosage setting element, designed as a dosing sleeve, has a coupling counter-surface with counter-engagement elements. Through a coupling movement, the coupling surface and counter-surface can be brought into engagement with one another, thus preventing relative movement between the coupling and dosing sleeve. In an alternative embodiment, the coupling surface and coupling counter-surface are always in engagement with one another, with the coupling movement being limited to blocking relative movement between the coupling and dosing sleeve. In a further preferred embodiment, the coupling surface and coupling counter-surfaces do not lie directly against one another, but are separated from one another by a so-called click disc. The click disc separates the relative movement of the coupling surface and coupling counter-surface, thus enabling optimization of the coupling properties.In particular, through clever shaping of the coupling surfaces, an acoustic feedback signal can be tailored to the user, informing them of the dose level during dosing and also during dose correction or dose change. The dosing device further comprises a dispensing button which is movably mounted at the proximal end of the dosing device. In a preferred embodiment of the dose setting member as a dosing sleeve, the dispensing button is attached coaxially to the dosing sleeve at its proximal end. The button is rotatable in particular relative to the dosing sleeve and is mounted with a certain degree of axial mobility. In a preferred embodiment, the coupling sleeve is also arranged coaxially to the dosing sleeve, wherein the coupling sleeve is preferably arranged at least partially within the dosing sleeve.In this embodiment, the coupling surface is arranged as an annular flange on the outer surface of the sleeve in its proximal region. Complementary to this, the coupling counter-surface is arranged, also in a ring shape, on the inside of the dosing sleeve. In one possible embodiment, the engagement elements and counter-engagement element are oriented axially to the injection device, so that in this case the coupling movement is an axial movement. For example, the coupling engagement can be achieved by pressing the dispensing button. The arrangement of dosing sleeve, coupling sleeve, and dispensing button can also comprise a spring which keeps the coupling surface and coupling counter-surface engaged. The dosing sleeve and coupling sleeve move axially together during a dosing movement, whereby relative rotation to one another is possible as long as the dispensing button is not pressed and the coupling is not blocked as a result.

[0013] In a preferred embodiment, the coupling sleeve is secured against rotation relative to the threaded nut, but is axially movable. This allows for axial movement of the coupling sleeve relative to the threaded nut. If the coupling is locked by pressing the dispensing button and the dosing sleeve is screwed into the injection device, the coupling sleeve also follows this movement. Via the anti-rotation feature of the threaded nut, only the rotation is transmitted to the threaded nut, thus moving the piston rod axially.

[0014] To ensure that the drive element, designed as a threaded nut, can only rotate in the direction that results in movement of the piston rod in the dispensing direction, i.e. in the direction that causes dispensing, a so-called anti-rotation device is preferably provided between the housing and the threaded nut. This is a radially directed or axially directed anti-rotation device. The anti-rotation device is designed in such a way that rotation of the threaded nut against the dispensing direction is completely blocked. When rotating in the dispensing direction, the anti-rotation device preferably has a certain resistance, also called reluctance, which must be overcome in order to bring about movement of the threaded nut. This is advantageous in order to prevent unwanted dispensing when correcting a dose that has been set too high.In particular, the rotational resistances of the anti-reverse device and the clutch are adapted to each other.

[0015] When the maximum pumpable product quantity is reached, the axial movement of the piston rod is blocked. For this purpose, at least one stop is arranged at the proximal end of the piston rod, which engages with a counter-stop arranged on the drive element as soon as the maximum pumpable product quantity has been pumped out of the injection device. The stop and counter-stop can act radially, i.e., perpendicular to the longitudinal axis of the injection device, through threaded ends. Alternatively, the stop and counter-stop can also act axially, i.e., parallel to the longitudinal axis of the injection device. In advantageous embodiments, axial and radial effects can also be combined. Detailed description of the drawings

[0016] Various embodiments are explained below with reference to figures. Accordingly, those skilled in the art will recognize that various changes and modifications can be made to the embodiments shown below without departing from the spirit or scope of the invention. The description of well-known functions and constructions is deliberately kept brief for clarity and understanding. List of drawings

[0017] Figure 1 Exploded view of the individual parts of a first embodiment of an injection device according to the invention Figure 2 View of the injection device according to the first embodiment Figure 3 Longitudinal section of the first embodiment in the initial state Figure 4 Longitudinal section of the first embodiment with the dose set Figure 5 Exploded view of the individual parts of a second embodiment of an injection device according to the invention Figure 6 Longitudinal section of the second embodiment in the initial state Figure 7 Detailed section of the coupling arrangement of the second embodiment Figure 8 Detailed section of the anti-reverse device of the second embodiment Figure 9 Exploded view of the individual parts of a third embodiment of an injection device according to the invention Figure 10 Longitudinal section of the third embodiment in the initial state Figure 11 Detailed section of the coupling arrangement of the third embodiment Figure 12 Detailed section of the anti-reverse device of the third embodiment Figure13Detail of the snap-in device for the threaded sleeve of the third embodiment

[0018] The Figures 1 to 4 show a first embodiment of the injection device. Figure 1 shows an exploded view of the individual parts, Figure 2 a representation of the assembled injection device in its delivery state, Figure 3 shows a longitudinal section through the injection device in its initial state before setting a dose and Figure 4 shows the same longitudinal section, but at a set dose.

[0019] The basis for the pen-shaped injection device is the housing 5. The cartridge holder 2, containing a cartridge 3, is attached to the housing 5 via a snap connection. The dosing device and the delivery mechanism are arranged at least partially within the housing. The threaded sleeve 9 is firmly inserted into the housing 5. The threaded sleeve 9 has an internal thread 9a. The threaded sleeve could also be part of the housing.

[0020] The dosing device comprises the dosing sleeve 11, the outer surface of which at least partially bears a thread 11c that engages the internal thread 9a of the threaded sleeve 9. The threaded connection between the threaded sleeve 9 and the dosing sleeve 11 is not self-locking. The rotary knob 11a, which allows the user to set the dose, is located at the proximal end of the dosing sleeve 11. The dosing sleeve 11 has numerical markings on its outer surface. When the dosing sleeve 11 is unscrewed from the housing 5 during the dosing process, the set dose is displayed in the window 9b of the threaded sleeve 9. Figure 3shows a longitudinal section through an injection device of the first embodiment in the initial state. The coupling 10 is arranged coaxially to the dosing sleeve 11. The coupling 10 has an annular flange 10b in its proximal region, which, upon axial movement of the coupling 10 relative to the dosing sleeve 11 in the distal direction, engages with a complementary annular counter-surface 11f of the dosing sleeve 11. The flange 10b has a coupling toothing 10c (as in Figure 1shown), which can be brought into engagement with a corresponding (counter-)toothing 11b on the counter-surface 11f. At the proximal end of the injection device, a dispensing button 14 is snapped onto the dosing sleeve 11 in such a way that the button 14 can move slightly axially relative to the dosing sleeve 11 and is freely rotatable. The possible movement of the dispensing button 14 is guided by corresponding guides at the proximal end of the coupling 10. The dosing click spring 13 is arranged between the dispensing button 14 and the coupling 10. In the initial state, the spring 13 presses the dispensing button in the proximal direction relative to the coupling. Due to the snap connection between the dispensing button 14 and the dosing sleeve 11, the coupling is pressed in the distal direction relative to the dispensing button 14 and the dosing sleeve 11 in response. Overall, the flange 10b and the counter-surface 11f are pressed against one another by the relaxation force of the spring.If the dosing sleeve 11 is now rotated relative to the coupling, the teeth of the counter surface 11f slide over the teeth of the flange 10b. This causes the coupling 10 to perform a repeated, slight axial movement in the proximal direction and back to its original position. With a suitable toothing shape, the relative rotation of the dosing sleeve 11 and the coupling 10 produces an audible and tactile click for the user. By pressing the dispensing button 14 in the distal direction against the spring force, relative rotation of the coupling 10 and the dosing sleeve 11 is prevented, so that the coupling 10 and the dosing sleeve 11 are secured against rotation relative to each other.

[0021] As can be seen from the Figures 1 and 4As can be seen, the coupling 10 is designed as a sleeve. On its inner surface, it has two opposing and axially oriented guides 10a, which are designed as ribs. These ribs engage in corresponding guides 7c, which are designed as axially running grooves on the outer surface of a threaded nut 7. Like the coupling 10, the threaded nut 7 is designed as a sleeve and is arranged coaxially to the coupling in the injection device, at least partially surrounded by the coupling 10. The threaded nut 7 is rotatable in the housing 5, but axially fixed. In the distal direction, the threaded nut 7 is held by a piston rod guide 5a of the housing 5; in the proximal direction, the threaded nut 7 is held by the housing insert 6 via the flange 7a. The housing insert 6 is firmly snapped onto the housing 5. Alternatively, it could also be part of the housing.On its inner side, the threaded nut 7 has a thread that engages with the external thread of the piston rod 8, which is designed as a threaded rod. The threaded rod 8 is mounted so as to be axially displaceable relative to the housing, but is secured against rotation by the piston rod guide 5a. For this purpose, the threaded rod has longitudinal grooves 8n. Rotation of the threaded nut 7 relative to the threaded rod 8 forces an axial movement of the threaded rod 8 relative to the threaded nut 7 and housing 5 due to the piston rod guide 5a. The threaded nut 7 has flexible arms 7b at its distal end, each of which has a tooth at its free end. The flexible arms 7b extend approximately radially outwards so that the teeth attached thereto engage with a ratchet (not shown) on the inside of the housing. For this purpose, the flexible arms 7b are preloaded, particularly in the radial direction, as soon as the threaded nut 7 is inserted into the housing 5.The arms, teeth, and ratchet are shaped so that the threaded nut 7 can only rotate in one direction, whereby a certain mechanical resistance, known as reluctance, must be overcome. In the position shown in . Figure 1In the embodiment shown, the threaded nut 7 can be turned in the direction which results in a movement of the threaded rod 8 in the distal direction. In the present embodiment, it is therefore not possible to move the threaded rod 8 in the proximal direction. At the distal end of the threaded rod 8, a flange 4 is attached which can act directly on the plug of the carpule 3. If the threaded rod 8 is moved in the distal direction, axial forces can be transferred from the threaded rod 8 via the flange 4 to the carpule plug, whereby a displacement of the carpule plug in the distal direction with the injection needle attached results in the release of product.Since the threaded nut rotates relative to the housing during dispensing, the flexible arms 7b also move relative to the housing, their teeth move over the housing ratchet and generate an acoustic, tactile signal that is perceptible to the user and can be used as dispensing feedback.

[0022] The function of the first embodiment of the injection device is briefly explained below. The first embodiment is designed as a so-called disposable pen. This means that the injection device is fully assembled, i.e., with the product to be administered, and is handed over to the user. Before use, the user only needs to vent, also known as prime, the injection device. The typical sequence of an injection process can be as follows: the user removes the protective cap 1 from the injection device and attaches an injection needle (not shown) to the needle holder 2a. The dose can now be set using the rotary knob 11a. To do this, the rotary knob 11a is turned so that the dosing sleeve 11 screws out of the injection device. The dosing sleeve is unscrewed from the injection device until the desired dose is displayed in window 9b.If a dose is accidentally set too high, the dose can be corrected by turning the knob in the opposite direction, which screws the dosing sleeve 11 back into the housing. The dosing device limits the maximum adjustable dose to a preset value. If an attempt is made to unscrew the dosing sleeve from the housing beyond this value, the radial stop 11e on the dosing sleeve 11 and the counter-stop 9d on the threaded sleeve 9 interact to prevent further rotation.

[0023] During dosing and correction movements, the dosing sleeve rotates relative to the coupling, resulting in a clicking sound due to the relative movement of the teeth 10c and 11b. Once the desired dose has been set, the injection needle can be inserted at the designated location on the user's body. The user then presses the dispensing button 14 in the distal axial direction, thus blocking relative rotation between the coupling 10 and the dosing sleeve 11. With further pressure in the distal axial direction, the dosing sleeve begins to rotate back into the housing in a screwing motion. Due to the established anti-twist device between the dosing sleeve and coupling, the coupling 10 performs the same movement as the dosing sleeve 11. Since the coupling 10 is permanently secured against rotation relative to the threaded nut 7, the rotational movement of the dosing sleeve 11 is transferred to the threaded nut 7.However, since the coupling 10 is mounted on the threaded nut 7 so that it can slide axially, no axial forces are transmitted to the nut. As already described above, the rotating threaded nut 7 generates an axial movement of the threaded rod 8 in the distal direction. The flange 4 acts on the plug of the carpule and displaces it, corresponding to the displacement of the threaded rod 8, in the distal direction, allowing the previously set dose to be dispensed or administered.

[0024] At the end of the administration, when the dosing sleeve has been completely screwed back into the housing, radial stops (11d, 9c) on the dosing sleeve 11 and the threaded sleeve 9 prevent over-tightening of the dosing device.

[0025] When the last possible amount of product to be administered has been dispensed, i.e. when the carpule 3 has been completely dispensed, the conveyor device blocks further dispensing rotation of the dosing sleeve 11. The threaded end 8a of the threaded rod 8 comes into contact with the ribs of the internal thread 7g of the threaded nut 7 and prevents further axial movement of the threaded rod 8 relative to the threaded nut 7. Since the threaded rod 8 is secured against rotation with respect to the housing, joint rotation of the threaded nut 7 and threaded rod 8 is also not possible. As a consequence, further screwing in of the dosing sleeve 11 is prevented as long as the anti-rotation lock between the coupling 10 and the dosing sleeve 11 is maintained. In the event that the user has set a higher dose than the amount of product still available, the remaining amount not administered can be easily read through window 9b on the dosing sleeve 11 when the device is blocked.This remaining amount can then be injected in a further administration procedure using a replacement injection device.

[0026] Figures 5 to 8 show a second embodiment of the invention. This second embodiment is fundamentally similar to the first embodiment and functions the same for the user. Differences are evident in the anti-reverse device and the coupling mechanism between the dosing device and the conveyor. In addition, the second embodiment has an alternative design of the dosing button. These changes are explained in more detail below. Figures 5 to 8 explained below. Identical designators in the figures, which refer to multiple embodiments, mean that the associated elements are essentially the same in the various embodiments.

[0027] Compared to the first embodiment, the coupling mechanism between the conveyor and dosing device of the second embodiment comprises an additional element, a click disc 115. The second embodiment comprises a dosing sleeve 111, which is in threaded engagement with the threaded sleeve 9. The coupling mechanism also comprises the coupling 110, which is arranged in the injection device analogously to the first embodiment. Although geometrically designed differently, the dispensing button 114 and the dosing click spring 113 function in the same way as in the first embodiment. In contrast to the first embodiment, the flange 110b and the counter surface 111f do not engage directly with one another, but are separated from one another by the click disc 115. As already explained in the description of the first embodiment, the coupling mechanism fulfills two functions.The first function is to couple the conveyor and dosing device, and the second function is to generate an acoustic click sound or a tactile change in resistance during the dosing movement and the dose correction movement. In the first embodiment, flange 10b and counter surface 11f are designed as a two-way slip clutch, whereby the geometric configurations of the toothings 10c and 11b must allow both directions of rotation, which can be disadvantageous for generating a clearly audible click sound or a tactile change in resistance. The second embodiment does not have a two-way slip clutch in the sense of the first embodiment. The rotational movements in the coupling mechanism between coupling 110 and dosing sleeve 111 occur spatially separated. The click disk 115 is arranged coaxially between the coupling flange 110b and the counter surface 111f of the dosing sleeve 111 (analogous to a washer).The two-sided click disc 115, comprising a first and a second coupling surface, has a proximal toothing 115o that engages with the coupling toothing 110c on the coupling flange 110b, and a distal toothing 115u that engages with the toothing 111b of the mating surface of the dosing sleeve 111. The toothings 110c, 111b, 115o, and 115u preferably have an asymmetrical geometric design of the individual teeth. Figure 7shows a preferred design of the toothing on the click disk 115. In this embodiment, for example, the distal toothing 115u has teeth which have a tooth flank 115a which is aligned approximately in the axial direction. The teeth 115u then have a second tooth flank 115b which is inclined with respect to the axial direction; preferably, the angle of inclination of the tooth flank 115 deviates by more than 0° but less than 90° from the axis of the injection device. The teeth of the toothing 115o are preferably designed in a similar way. The teeth 115o are aligned such that, in an advantageous design, they are shaped so as to be mirrored to the toothing 115u with respect to a sectional plane which is perpendicular to the longitudinal axis of the injection device. The toothings 110c, resp. 111b, the coupling 110, or the dosing sleeve 111 are designed to complement the toothings 115o, or 115u.The described advantageous design of the coupling mechanism between the dosing device and the conveying mechanism results in a separation of the sliding surfaces, which move relative to one another and within the coupling mechanism during dose setting on the one hand and dose correction on the other. Due to the asymmetric shape of the teeth 115o, 115u, 110c, 111b, no relative movement can occur between the coupling 111 and the click disc 115 during an increase in the dose because the axially directed tooth flanks prevent any movement. Conversely, when the dose is increased, the dosing sleeve can be moved relative to the click disc due to the tooth flank orientation. During dose correction, the exact opposite is true, meaning that relative movement between the coupling and the click disc is possible and movement between the dosing sleeve and the click disc is prevented.The dosing spring 113 generates a force that presses the mutually arranged toothings of the clutch mechanism into each other. When the interlocking toothings move relative to each other, the individual teeth shift along the non-axially aligned tooth flank and apply an increasing restoring force to the dosing click spring 113. This increase in restoring force is noticeable to the user and can serve as tactile feedback. After passing over the tooth tips, the teeth jump back to their axial starting position along the axially aligned tooth flanks, driven by the restoring force of the spring. When the axial starting position is reached, the impact of the tooth surfaces on each other produces an acoustic signal, also known as a click.Due to the axial alignment of one tooth flank, when the teeth move into their axial starting position, a maximum of the spring's stored energy is used to generate the clicking sound and only a minimum is used to further shift the teeth relative to one another. Compared to the first embodiment, the second embodiment of the coupling mechanism between the dosing device and the conveyor shown here has the advantage that more perceptible acoustic feedback signals can be generated with the second embodiment during dosing and dose correction. Further variations are also conceivable, particularly in connection with the tactile feedback described. For example, the toothings 115u and 115o can have teeth of different heights with the same width, with the teeth on the dosing sleeve 111 and the coupling 110 being complementary to the associated teeth on the click disk 115. This refers in particular to the axial height of the teeth.As a result, the dosage click and the dose correction click can be acoustically distinguishable. In another exciting embodiment, the teeth 115u and 115o can have different widths, in particular, a different angle of rotation. For example, a tooth 115o can be twice as wide as a tooth 115u, so that each dose correction click sets back twice the dose that is raised with a dosage click.

[0028] Analogous to the first embodiment, the threaded nut 107 of the second embodiment is mounted axially fixed to the housing but rotatable. A reverse rotation lock additionally ensures that the threaded nut can only rotate or turn in one direction relative to the housing. However, compared to the first embodiment, the reverse rotation lock of the second embodiment is constructed differently. The threaded nut 107 is surrounded at its distal end by an annular toothed disk 117. The toothed disk 117 is mounted so as to be longitudinally displaceable relative to the threaded nut 107 but secured against rotation and is arranged coaxially to the threaded nut. For this purpose, the toothed disk 117 has axially proximally projecting guide cams 117b which are guided in the guide surfaces 107d of the threaded nut. The toothed disk further comprises a toothing 117a projecting in the distal direction which can engage with a provided counter toothing 105b of the piston rod guide 105a.A return spring 116 supported on the flange 107a presses the toothed disk 117 in the distal direction, so that the toothing 117a engages the counter-toothing 105b with a defined axial force. As shown in . Figure 8As shown, the toothing 117a is advantageously designed asymmetrically, so that a relative rotation of the toothed disk 117 to the housing 105 is possible and prevented in the other direction. The fact that the toothed disk 117 is arranged on the threaded nut in a rotationally secure manner means that the threaded nut can also only rotate in one direction. Compared to the anti-rotation device of the first embodiment, the anti-rotation device of the second embodiment has the advantage of being easier to manufacture. In addition, the anti-rotation device of the second embodiment is not prone to relaxation phenomena.A further advantage is that by introducing a separate spring, the rotational resistance of the threaded nut when rotating in the permitted direction can be varied by selecting a suitable spring without having to adapt the design - which is not possible with the first embodiment, which allows the acoustic and tactile release feedback as well as the reluctance to be controlled.

[0029] Compared to the first embodiment, the geometric design of the dispensing button 114 is also changed in the second embodiment. However, this geometric change has no significant impact on the function.

[0030] For the user, the changes made in the second embodiment compared to the first embodiment do not result in any fundamental differences in operation.

[0031] A third embodiment of the injection device is shown in the Figures 9 to 13 The third embodiment is based on the second embodiment. An advantage of the third embodiment over the second embodiment results from the reduction in the number of required components. A difference between the second and third embodiments results from the modified arrangement of the anti-reverse device, which in the third embodiment is no longer located on the threaded nut, but on the coupling, which makes it possible to combine the anti-reverse spring with the dosing click spring. The specific details of the third embodiment are explained below.

[0032] The anti-rotation device of the third embodiment comprises an annular toothed disk 217 which is mounted in the housing 205 so as to be movable but not rotatable. The mounting takes place via guide ribs 217b on the toothed disk 217 and guide grooves 205c on the inside of the housing. The toothed disk 217 comprises an asymmetric toothing 217a oriented axially in the distal direction. In the third embodiment, the coupling 210 has, at its distal end, an asymmetric counter-toothing 210d oriented axially in the proximal direction, which can engage with the toothing 217a. As in the design of the second embodiment, the asymmetric shape of the teeth 217a and 210d serves to permit relative movement in only one direction.A return spring 216 ensures that a force acts on the toothed disc 217 in the distal direction, which ensures that the toothed disc 217 can be brought into engagement with the toothing 210d on the coupling 210 after assembly of the injection device.

[0033] In the third embodiment, the return spring 216 not only acts on the toothed disk 217 in the distal direction, but also on the dosing sleeve 211 in the proximal direction. In the advantageous embodiment shown, the return spring 216 is arranged coaxially, outside the coupling 210, and is clamped between the distal end of the dosing sleeve 211 and the toothed disk 217. When setting a dose, the toothed disk 217 and the return spring 216 follow the axial movement of the coupling 210 and the dosing sleeve 211. This arrangement results in the second effect of the return spring 216. Since it directly presses the dosing sleeve 211 in the proximal direction and indirectly presses the coupling 210 (via the toothed disk 217) in the distal direction, this also has an effect on the coupling mechanism between the dosing device and the conveying device. As in the second embodiment, coupling 210 and dosing sleeve 211 are coupled to each other via a click disc 215.The click disc 215 is fundamentally constructed in the same way as the click disc 115 and functions in the same way as the click disc 115. The force of the return spring 216 on the coupling 210 and the dosing sleeve 211 causes the teeth 210c to engage with the teeth 215o, and the teeth 211b to engage with the teeth 215u. The second action of the return spring 216 thus replaces the action of the dosing click spring 113 from the second embodiment; therefore, a dosing click spring is no longer required in the third embodiment of the injection device.

[0034] In a further simplification from the second embodiment, the housing insert 106 of the second embodiment can be replaced in the third embodiment by a snap-in device 205d formed integrally with the housing 205 as in Figure 13shown. During assembly of an injection device of the third embodiment, the flange 207a of the threaded nut 207 is snapped into the snap-in device 205d of the housing 205 upon insertion. To simplify this process, the flange 207a has bevels 207e, which guide the temporary geometric deflection of the snap-in device 205. List of identifiers

[0035] 1Protective cap 2Carpule holder 2aNeedle holder 3Carpule 4Flange 5Housing 5aPiston rod guide 6Housing insert 7Threaded nut 7aFlange 7bFlexible arms 7cGuide 7gThread 8Threaded rod 8aThreaded end 8gThread 8nLongitudinal grooves 9Threaded sleeve 9aInternal thread 9bWindow 9cStop 9dCounter stop 10Coupling 10aGuide 10bFlange 10cCoupling teeth 11Dosing sleeve 11aRotary knob 11bTeeth 11cExternal thread 11dProximal radial stops 11dIstinal radial stop 11fCounter surface 12Metal ring 13Dosing click spring 14Dispensing button 105Housing 105aPiston rod guide 105bCounter teeth 107Threaded nut 107aFlange 107dGuide surfaces 110Coupling 110bFlange 110cCoupling teeth 111Dosing sleeve 111aRotary knob 111bTeeth 111fCounter surface 113Dosing click spring 114Dosing knob 115Click disc 115aTooth flank 115bTooth flank 115Proximal toothing 115Udistal toothing 116Return spring 117Tooth disc 117aTeeth / teeth 117bGuide cam 205Housing 205aPiston rod guide 205cLongitudinal guide grooves205dSnap-on device 207Threaded nut 207aFlange 207eBevel 210Coupling 210cCoupling teeth 210dCounter teeth 211Dosing sleeve 211bTeeth 214Dosing button 215Click disc 215oTooth flank 215uTooth flank 216Return spring 217Tooth disc 217aTeeth / teeth 217bGuide ribs

Claims

1. An injection device for administering or delivering fluid product, preferably a pen-shaped injection device, comprising - a housing (5, 105, 205) having a receptacle (2) for the product, - a delivery apparatus having a piston rod (8) which is movable relative to the housing (5) in a delivery direction by a delivery stroke in order to dispense a set product dose in a delivery stroke corresponding to the set product dose, wherein the delivery apparatus can move the piston rod (8) to deliver product and for this purpose comprises a guide element (5a, 105a, 205a), which guides the movement of the piston rod (8), and a drive element (7, 107, 207), which is in engagement with the piston rod (8); - a dosing unit for setting a product dose to be administered, the unit having a dosing sleeve (11, 111, 211) and a rotary knob (11a) and having a dispensing button (14, 114, 214) arranged coaxially on the dosing sleeve (11, 111, 211), and wherein the dosing unit for administering or delivering fluid product is coupled to the delivery apparatus via a coupling mechanism, and in that - the coupling mechanism consists of at least two coupling surfaces which each carry toothing (10c, 110c, 210c, 11b, 111b) made up of teeth, and wherein the coupling surfaces (10b, 110b, 11f) are used, during the dosing process or during dose correction, to generate an acoustic and / or tactile signal corresponding to the set or corrected dose of the product to be administered by means of a relative movement, and wherein the relative movement between the at least two coupling surfaces (10b, 110b, 11f) can be prevented by releasing the dispensing button (14, 114, 214), characterized in that the coupling mechanism has a coupling member (10, 110, 210) which is arranged on the drive element (7, 107, 207) in a rotationally secure but axially displaceable manner, and - one of the at least two coupling surfaces (10b, 110b, 11f) is fixedly attached to the coupling member (10, 110, 210), and another of the at least two coupling surfaces (10b, 110b, 11f) is fixedly attached to the dosing sleeve (11, 111, 211) so that the coupling surface (10b, 110b) of the coupling member (10, 110, 210) and the coupling surface (11f) of the dosing sleeve can be brought into coupling engagement with one another directly or indirectly, wherein a radially or axially directed reverse-rotation lock (7b) is arranged between the housing (5, 105, 205) and the drive element (7, 107, 207) so that the drive element (7, 107, 207) can only rotate in the dispensing direction and the drive element (7, 107, 207) is blocked from rotating counter to the dispensing direction.

2. An injection device according to claim 1, the coupling engagement being indirect, characterized in that a click disk (115, 215) having a first and a second coupling surface is arranged between the coupling surfaces (10b, 110b, 11f) of the coupling member (10, 110, 210) and the dosing sleeve (11, 111, 211), the first coupling surface of the click disk (115, 215) having toothing (115o) which is complementary to the toothing (110c, 210c) on the coupling member (110, 210), and the second coupling surface of the click disk (115) being complementary to the toothing (111b) on the dosing sleeve (111, 211).

3. An injection device according to claim 2, characterized in that the teeth of the toothing (115o, 115u) have an asymmetrical shape so that, when the dispensing button (11, 114, 214) is not released, a relative movement between the dosing sleeve (111, 211) and the click disk (115, 215) can take place in one direction and a relative movement between the coupling member (110, 210) and the click disk (115, 215) can take place in the opposite direction.

4. An injection device according to claim 3, characterized in that the teeth of the toothing (115o, 115u) of the first and the second coupling surface have a different height.

5. An injection device according to claim 3 or 4, characterized in that the teeth of the toothing (115o, 115u) of the first and the second coupling surface have a different width.

6. An injection device according to any of claims 2 to 5, characterized in that the click disk (115, 215) is arranged coaxially to the dosing sleeve (111, 211).

7. An injection device according to any of claims 2 to 6, characterized in that during the dosing process, the dosing sleeve (111, 211) is moved relative to the click disk (115, 215), and the movement between the dosing sleeve and the click disk being prevented during the dose correction.

8. An injection device according to any of the preceding claims, characterized in that the at least two coupling surfaces (10b, 110b, 11f) can be brought into engagement by means of a spring (13, 113, 216).

9. An injection device according to any of the preceding claims, characterized in that the dosing sleeve (11, 111, 211) is in threaded engagement with the inside of the housing (5, 105, 205) and a grippable element (11a) is attached to the proximal end.

10. An injection device according to any of the preceding claims, characterized in that the injection device is designed as a disposable pen.

11. An injection device according to any of the preceding claims, characterized in that the guide element (5a, 105a, 205a) is designed as a longitudinal guide for the piston rod (8), which is fixed to the housing, and the drive element (7, 107, 207) is designed as a threaded nut which is rotatably but axially fixedly mounted in the housing (5, 105, 205) and the internal thread of which is in engagement with a corresponding external thread (8g) mounted on the outer surface of the piston rod, or via so-called kinematic reversal, the threaded nut being rotatably secured to the housing as a guide element and the piston rod being connected to a rotatable and displaceable longitudinal guide of the drive element (7, 107, 207) so that the piston rod can rotate due to the thread of the threaded nut.

12. An injection device according to claim 11, characterized in that the axial movement of the piston rod (8) is blocked when the maximum deliverable product quantity is reached.

13. An injection device according to claim 12, characterized in that at least one stop (8a) is arranged at the proximal end of the piston rod, which stop can come into engagement with a counter-stop (7) arranged on the threaded nut (7) and, as a result, a further axial movement of the piston rod (8) relative to the threaded nut (7) is prevented.