Autoinjector with push-release

Abstract

The invention relates to an automatic injector having a housing, a product container axially fixed in the housing, a torsion spring, a drive element, a thrust element and a needle guard, wherein the needle guard performs an actuation movement in the proximal direction when the automatic injector is pressed onto an injection site. In order to push liquid out of the product container through the injection needle into the injection site, the torsion spring rotates the drive element, and the rotating drive element causes the thrust element and the piston in the product container to move in the distal direction. The automatic injector comprises a coupling, which releases the drive element for rotation due to the actuation movement of the needle guard. The coupling comprises a first coupling element, which engages in a second coupling element via an axial locking surface, wherein the engagement can be released by an axial coupling stroke of the two coupling elements.

Description

Technical Field

[0001] The invention relates to the field of medical injection devices for administering liquid substances, in particular drugs or medicinal substances such as insulin and hormone preparations. The invention relates to an automatic injector with an energy storage device for ejecting a predetermined dose from a disposable product container. Background Art

[0002] Injection devices or injection devices for simplifying the administration of substances further include so-called automatic injectors, which have an energy accumulator with which the ejection can be performed automatically, that is, without external input or application of force by the user. The energy accumulator advantageously stores the energy required for the automatic substance output in a mechanical form. Such an energy accumulator can be a spring, which is loaded into the injection device in a tensioned state and outputs energy by relaxation. The energy output is carried out on a piston rod or a pressure element, which pushes the piston into the product container. The energy accumulator can also be arranged to automate the process of injection needle piercing. Alternatively, the piercing process can be performed manually, that is, only by the user, without the need to use the energy stored in the injection device for this purpose.

[0003] The injection device may include a product container holder for accommodating a product container, wherein the product container can be radially, axially and preferably also held in the product container holder in a rotationally fixed manner. The product container holder can be axially fixedly and rotationally connected to the housing of the injection device, or can be moved relative to the housing during the piercing process and / or needle retraction process. The product container can be a cartridge injector (karpule) for disposable or repeated releasable connection with a disposable injection needle or a disposable prefilled injector (fertigspritze) with an injection needle that is non-releasably connected thereto. The product container has a hollow cylindrical product container section, which movably supports a piston or a stopper. The piston can form a sealing gap with the inner circumference of the product container section and move in the distal direction by means of a piston rod to output the product from the product container through the injection needle.

[0004] The injection device may have a needle guard which, after the injection has been completed, protrudes distally beyond the distal end of the injection needle or moves relative to the housing into this position when the needle guard spring is relaxed, in order to prevent accidental access to the injection needle and thereby reduce the risk of injury. For an autoinjector, the needle guard may also serve as a trigger element to trigger the ejection of the product, wherein the needle guard is moved relative to the housing in the proximal direction for this purpose. Alternatively, the triggering of the autoinjector may be achieved by actuating a trigger button of the autoinjector, wherein the needle guard serves at least as a visual protection before the autoinjector is used.

[0005] Patent application WO 2016 / 205963 describes an exemplary automatic injector, which includes a housing with a longitudinal axis and a product container axially fixedly arranged in the housing. The automatic injector also includes a needle protection sleeve, which can be moved in the longitudinal direction between the proximal position and the distal position and is coupled to the needle protection spring. The spiral spring or transmission spring is connected to the housing through a first end and is connected to a drive element arranged coaxially to the longitudinal axis in the form of a rotating threaded rod in a rotationally non-rotatable manner through a second end, in which energy for automatically ejecting the product can be stored. The threaded rod is threadedly engaged in a propulsion member in the form of a propulsion sleeve that does not rotate in the housing, and the propulsion sleeve drives the stopper of the product container at least approximately constant ejection speed when moving in the distal direction. Before ejection, the retaining element engages in the recess of the propulsion member with two flexible retaining arms and prevents the movement of the propulsion member. The arm of the retaining element is held in the engagement by a locking sleeve. When the ejection is triggered, the locking sleeve moves out of the position of the recess by the proximal movement of the needle guard, so that the retaining arms can be radially loosened and the push member is released. Before the ejection and in certain cases over the course of several years, the torque of the coil spring is applied via the drive element to the proximal end of the push member and the push force is applied to the retaining element, which leads to static material loads of the push member and the retaining arms and can lead to possible fatigue phenomena.

[0006] Patent application WO 2009 / 037141 A1 describes an automatic injector with ejection motion for highly viscous drugs, wherein the needle guard pushes the trigger sleeve in the proximal direction by a small trigger stroke when placed on the injection site and thereby releases the radial engagement between the trigger sleeve and the drive member. The drive member is driven by a helical spring and pushes the piston rod in the axial direction by a threaded connection with the proximal thread of the built-in piston rod, which is responsible first for the automatic piercing motion and then for the ejection of the drug. The piston rod also includes a distal portion, the diameter of which is greater than the diameter of the threaded proximal portion of the piston rod.

[0007] Patent application WO 2017 / 089254 A1 describes an automatic injector with a transmission spring which is released from the outside by the user via engagement on the proximal end of the threaded rod.

[0008] The terms "product", "drug" or "medical substance" in this context include any flowable medical preparation, such as a liquid, solution, gel or fine suspension containing one or more medically active ingredients, which is suitable for controlled administration into subcutaneous or muscle tissue by means of a cannula or a hollow needle. Thus, the drug can be a composition with only one active ingredient, or a premixed or co-formulated composition with multiple active ingredients from a single container. The term includes in particular pharmaceutical products, such as peptides (e.g. insulin, drugs containing insulin, containing GLP-1 and derivative or similar preparations), proteins and hormones, biologically obtained or effective active ingredients, hormone-based or gene-based active ingredients, nutritional preparations, enzymes and other substances, whether in solid (suspended) or liquid form. The term also includes polysaccharides, vaccines, DNS or RNS or oligonucleotides, antibodies or antibody parts, as well as suitable basic substances, auxiliary agents and carrier substances.

[0009] The term "distal end" refers to a side or direction of the end of the front portion of the drug delivery device, the end of the piercing side, or the tip of the injection needle. In contrast, the term "proximal end" refers to a side or direction of the end opposite to the end of the piercing side at the rear portion of the drug delivery device.

[0010] In the present description, the term "injection system" or "injector" is understood to be a device for which the injection needle is removed from the tissue after the delivery of a controlled amount of a medical substance has been completed. Thus, in an injection system or in a syringe, the injection needle does not remain in the tissue for a prolonged period of several hours, unlike an infusion system. Summary of the invention

[0011] The object of the present invention is to provide an automatic injector with a torsion spring drive for automatically ejecting liquid from a prefilled syringe fixed to a housing, wherein the torque of the torsion spring is reliably blocked or absorbed until the planned ejection. This object is achieved by an automatic injector and a drive unit having the features of the independent claims. Preferred embodiments of the invention are the subject matter of the dependent claims.

[0012] The automatic injector according to the present invention comprises a one-piece or multi-piece housing with a longitudinal axis and a pre-filled prefilled injector, which has a product container and an injection needle or cannula that is non-releasably fastened thereon. The prefilled injector is axially non-movably accommodated in the housing, wherein the tip of the injection needle protrudes in the distal direction from the distal housing end at the piercing depth. The automatic injector also includes a torsion spring, a drive element, a propulsion element and a needle protection sleeve that are pre-tightened to push out the maximum content of the product container at one time. In order to push out the liquid from the product container through the injection needle, the torsion spring rotates the drive element around the longitudinal axis, and the rotating drive element causes the linear movement of the propulsion element to move the piston in the product container. When the automatic injector is pressed against the injection site and the injection needle is thereby caused to penetrate into the injection site, the needle protection sleeve moves along the proximal direction with an actuation stroke and thereby starts or enables the liquid to be pushed out. Here, the actuation stroke of the needle protection sleeve corresponds at least to the penetration depth of the injection needle.

[0013] The automatic injector finally comprises a coupling, which does not comprise a propulsion element and is independent of the propulsion member, which coupling only has a coupling element different from the propulsion element, which prevents the rotation of the drive element before ejection and, as a result of the movement of the needle guard during piercing, releases the drive element or the rotation element connected to the drive element in a torsionally fixed manner for rotation. The coupling therefore does not prevent the linear movement of the propulsion element, but directly prevents the torque of the torsion spring on the drive element. This prevents the torsionally fixed connection or coupling of the drive element and the propulsion element from being loaded and possibly damaged during the entire storage period of the automatic injector.

[0014] Advantageously, all coupling elements of the coupling are located distally of the torsion spring or on the needle guard side, so that the drive element does not extend beyond the proximal end of the torsion spring. It is further preferred that no recess for engaging the retaining element is provided in the pusher element, so that the pusher element can be screwed onto the thread to different degrees during assembly, depending on the specified ejection stroke or the axial initial position of the stopper. For partially filled prefilled injectors, the pusher element is not screwed over the entire length of the transmission, so that a small portion of the maximum ejection stroke can be easily adjusted.

[0015] In a preferred embodiment, the coupling comprises an inwardly directed first coupling element which selectively engages in an outwardly directed second coupling element via a locking surface which acts counter to a rotation about the longitudinal axis and is preferably oriented parallel to the longitudinal axis, wherein the engagement is released by an axial coupling stroke or axial relative movement of the two coupling elements. By means of this axial movement, no additional space is required in the radial direction in the autoinjector, in contrast to a radial decoupling in which the first coupling element moves away from the second coupling element in the radial direction.

[0016] The coupling stroke, which can be carried out manually or with spring support without a transmission ratio, corresponds to the actuation stroke of the needle guard during puncture and therefore at least to the puncture depth of the injection needle, which itself is at least 3 mm and preferably at least 5 mm. The torque of the torsion spring is locked or accommodated parallel to the longitudinal axis of the automatic injector by a coupling element with locking surfaces. The axial extension of these locking surfaces is lower than the size of the coupling stroke, but is advantageously at least 2 mm, preferably at least 4 mm, and can also correspond in practice at least to the puncture depth.

[0017] In a preferred embodiment, the propulsion element has a non-rotationally symmetrical cross section, which has an axial guide element in the form of a groove, a plane or a rib parallel to the longitudinal axis, by which the propulsion element is axially and linearly guided by the housing or a guide counterpart element accommodated in the housing in a rotationally fixed manner. Here, the propulsion element is coupled to the drive element by a thread and only moves axially in the ejection direction, rather than, for example, in a spiral propulsion movement. Friction between the end face of the distal end of the propulsion member and the piston is thereby avoided, and in addition, it is easier to provide the drive element and / or the propulsion element with a thread suitable for generating a changed ejection force or to provide a special thread surface coating than to provide the housing. The propulsion element can be screwed to different degrees when screwed into the thread of the drive element or when tightened onto the thread of the drive element, depending on the prescribed ejection stroke or axial initial position of the plug. If the housing and / or the axial guide element allow a plurality of discrete rotational positions of the propulsion element, i.e. if the propulsion element can be guided through the housing in a first orientation and in a second orientation rotated around the longitudinal axis by 180° or even only 90° relative to the first orientation, then part of the propulsion stroke can be adjusted with a resolution of less than one thread pitch, in particular half the thread pitch or even only a quarter of the thread pitch.

[0018] Further preferably, the drive element has a threaded rod with an external thread, and the thrust element has a thrust sleeve with an axial guide element and an internal thread adapted to the external thread. The internal thread extends over a length corresponding to the maximum ejection stroke, and the external thread is shortened to a small number of turns at the proximal end of the threaded rod, or comprises a thread section of less than one turn. Alternatively and in an injection molding-technically advantageous manner, the external thread extends over the maximum length of the ejection stroke and the internal thread is shortened accordingly. When the threaded rod rotates, the non-rotatably mounted thrust sleeve is pushed in the distal direction, which is easier to achieve than a linear guidance of the threaded rod.

[0019] The torsion spring as an elastic mechanism for generating torque is preferably a helical spring, but can also be configured as a leaf spring, a transmission spring, a conical spring, a coiled torsion spring, a torsion bar or a combination thereof. At the time of delivery or before the automatic injector is put into operation, in order to push out the entire content of the product container or at least the predetermined content at one time, the torsion spring is prestressed to the maximum or sufficient extent. Accordingly, the automatic injector does not have a dose selection mechanism. The prefilled disposable prefilled injector includes a product container and an injection needle that is non-releasably fastened thereon and is axially fixedly held in the housing of the automatic injector. The automatic injector or at least the prefilled injector and the injector holder are correspondingly only provided for disposable use.

[0020] In a preferred embodiment, the coupling comprises a coupling sleeve with inwardly directed teeth or projections as a first coupling element, which radially engages in a second coupling element, which is connected to the drive element in a rotationally fixed manner or is formed integrally with the drive element. The second coupling element comprises outwardly directed teeth or recesses on the drive element or on the spring coil connected to the drive element and the torsion spring in a rotationally fixed manner. The coupling sleeve is a separate component of the automatic injector and in particular does not comprise a locking member for locking the needle protection sleeve in the needle protection position after the injection has been completed.

[0021] In a preferred embodiment, the coupling sleeve has a retaining element which is released by the actuation movement or actuation stroke of the needle protection sleeve. Subsequently, the coupling sleeve with the first coupling element is moved axially and preferably in the proximal direction relative to the second coupling element during the coupling stroke by a spring, preferably a needle protection spring, and the drive element is released. Preferably, the coupling stroke of the coupling sleeve is limited by a distally directed stop on the mechanical support, whereby an acoustic signal can be generated which signals the start of ejection to the user.

[0022] In a preferred embodiment, one end of the torsion spring is coupled to the shaft of the spring coil in a rotationally fixed manner, and the spring flange defines a receiving area or volume of the torsion spring at the distal end. The second coupling element is spaced apart from the distal spring flange by at least the length or amplitude of the coupling stroke and is arranged on a widened portion of the spring coil, which is coupled to the drive element in a rotationally fixed manner, and the spring coil comprises a coil sleeve or a coil flange.

[0023] In a preferred embodiment, the coupling sleeve is a locking sleeve and has a locking member for locking the needle protection sleeve in the needle protection position at the end of the injection. Advantageously, the second coupling element is arranged on a drive sleeve as a drive element and its proximal end is spaced apart from the distal spring flange by at least the length of the coupling stroke. The drive sleeve is threadedly engaged with an advancement member in the form of a piston rod.

[0024] Further preferably, the drive sleeve and the locking sleeve have a sliding guide control with a first guide element and a second guide element, for example radially oriented guide cams, which engage in the guide grooves. The guide elements are designed and interact in such a way that after the rotation of the drive sleeve is released, the drive sleeve pushes the locking sleeve in the proximal direction with an initial rotation of at most 45° and a latching travel of at least 1 mm. This ensures that the locking sleeve reliably reaches its latching position even in the most unfavorable tolerance conditions. Advantageously, the guide cams are mounted on the drive sleeve and the guide grooves are arranged in the locking sleeve and are oriented at an angle to the longitudinal axis.

[0025] The automatic injector optionally comprises a permanently installed rotation sensor for continuously detecting at least one rotation position and preferably at least two rotation positions per revolution of the drive element during ejection, and the automatic injector comprises a processor unit for determining the axial piston position of the piston in the product container or the residual volume in the product container from the successively detected rotation positions. The rotation of the drive member directly caused by the torsion spring during ejection is continuously and preferably measured with a resolution of half a revolution or less, and the advancement and piston position are determined from this. The improved resolution allows the residual volume or the amount of drug ejected to be determined precisely, which is important in particular when the ejection does not proceed as planned or is even interrupted by the user. In addition, the progress of the ejection can be detected in real time, and in particular, fluctuations in the advancement speed can be recognized without delay.

[0026] The automatic injector may also optionally include an optical, acoustic or tactile signaling unit or display unit having an electronically controlled actuator. After determining the axial piston position corresponding to at least almost complete ejection and after a predetermined holding time has passed, the actuator is controlled or activated by the processor unit. This generates a signal that shows the end of the injection and gives the user confirmation that the automatic injector can now be reliably moved away from the puncture site. Accordingly, the automatic injector does not have a purely mechanically triggered end button (Endklick), in which the stop element is accelerated by a spring. The holding time is usually a few seconds, preferably at least 3 seconds, and ensures that the amount of the injected drug is completely absorbed or reabsorbed by the subcutaneous tissue, and that no fluid passes through the puncture site to reach the tissue surface after the automatic injector is removed.

[0027] The automatic injector preferably has an electronic module, which has a circuit board and a sensor unit arranged thereon for detecting a state or process, a processor unit for processing the signal of the sensor unit, a communication unit for wirelessly transmitting the data of the processor unit to a third device, and a battery for powering the above-mentioned unit. Communication with a fixed third device, such as an expert system in a remotely located or cloud-based infrastructure, can be carried out, for example, via a 5G or 4G / LTE mobile radio network, especially a narrowband Internet of Things NB-IoT. Communication with a mobile third device, such as a mobile phone or a smart phone, or with a fixed gateway to a wired network is preferably carried out via a Bluetooth or BLE connection, which is advantageously started by out-of-band pairing. The electronic module also includes an optical, acoustic and / or tactile display unit, such as an optical display, in which the light conductor guides the light of the light source on the circuit board to the surface of the housing. The state displayed by the display unit can include information related to the drug, the instrument state of the automatic injector, the module state of the electronic module, or the process state of an ongoing or completed injection process. The display unit of the electronic module can be kept simple and limited to a few LEDs, for example in traffic lights or for illuminating selected guideposts and / or an acoustic signal generator for generating noises or melodies that are not related to speech. This is particularly advantageous in conjunction with the advanced graphic display and speech output possibilities of a smartphone, since the smartphone wirelessly coupled to the electronic module assumes more sophisticated communication with the user that goes beyond status displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. These embodiments should reveal the basic possibilities of the present invention and should not be construed as limiting. It is shown in the drawings:

[0029] Figure 1Components of a first variant of an automatic injector are shown,

[0030] Figure 2 Shown before injection through Figure 1 A longitudinal cross-sectional view of an automatic injector,

[0031] Figure 3 Shown through Figure 2 Cross section of an automatic injector,

[0032] Figure 4 Shown during injection through Figure 1 A longitudinal cross-sectional view of an automatic injector,

[0033] Figure 5 Shown after injection through Figure 1 A longitudinal cross-sectional view of an automatic injector,

[0034] Figure 6 Components of a second variant of an automatic injector are shown,

[0035] Figure 7 Shown before injection through Figure 6 A longitudinal cross-sectional view of an automatic injector,

[0036] Figure 8 Shown through Figure 7 Cross section of an automatic injector,

[0037] Fig. 9 Shown during injection through Figure 6 A longitudinal cross-sectional view of an automatic injector,

[0038] Fig.10 Show Figure 6 an actuating element of an automatic injector, and

[0039] Fig.11 Shown after injection through Figure 6 Longitudinal cross-sectional view of an automatic injector. DETAILED DESCRIPTION

[0040] Figure 11 is an exploded view of the components of an automatic injector according to a first variant of the invention. The automatic injector has a sleeve-shaped elongated housing with a longitudinal axis L and comprises a distal housing part 10a and a proximal closure cap or end cap 10b which is non-releasably engaged with the distal housing part. The distal housing part 10a and the closure cap 10b have the same cross section over the entire length of the automatic injector, and the closure cap comprises a single end face perpendicular to the longitudinal axis. The product container is held in the injector holder 12 in the form of a prefilled injector 11 with an injection needle non-releasably fastened to the product container, wherein the injector holder is axially fixed and non-rotatably accommodated in the housing 10a. The prefilled injector 11 is pressed into engagement with the shoulder of the injector holder 12 in the distal direction by a retaining spring section of a mechanical holder 13 firmly anchored in the housing 10b. The prefilled injector 11 is arranged in relation to the housing 10a so that the tip of the injection needle protrudes beyond the distal end of the housing 10a by a length corresponding to the subcutaneous or muscular penetration depth and is protected or covered at least laterally by the needle protection sleeve 14 before and after the injection. When the injection needle is inserted into the injection site, the needle protection sleeve 14 is pushed along the longitudinal axis L with an actuation stroke and against the force of the needle protection spring 15 in the proximal direction and thereby triggers the product to be ejected, as will be described in detail below. The needle protection sleeve includes two sleeve arms 14a for this purpose, which are arranged 90° offset or twisted 90° around the longitudinal axis L relative to two recesses 10c of the housing, which are called observation windows. After the injection is completed, the needle protection sleeve 14 can be moved from the actuated position along the longitudinal axis L in the distal direction to the needle protection position relative to the housing 10 and is prevented from being pushed back again there. The needle protection spring 15 is a spring made of metal, which acts as a compression spring and is configured as a coil spring (Wendelfeder).

[0041] The spring group 20 comprises a helical spring 20a, a spring coil 20b and a spring sleeve 20c. The helical spring 20a is anchored to the spring sleeve 20c with its outer end in a torsion-proof manner, and the spring sleeve is again torsion-proof accommodated in the housing 10a. The two outermost turns of the helical spring can be fixed tangentially, for example welded, so that the outermost turns themselves act as an integrated spring sleeve. The inner end of the helical spring 20a is connected to the spring coil 20b in a torsion-proof manner. The spring coil 20b comprises a spring shaft and a spring flange at the distal end and a spring flange at the proximal end that axially limit the spring volume. The spring group 20 can be fully preloaded as an independent component and assembled in the housing of the automatic injector and accommodate helical springs of different widths, as described in detail in the patent application WO 2016 / 205963 mentioned at the beginning. Here, WO 2016 / 205963 is fully incorporated into the present application by reference.

[0042] For simpler assembly, the automatic injector is composed of two subunits or components. In this case, the distal injector unit of the automatic injector includes a distal first housing part 10a, a needle protection sleeve 14, an instrument cover 16 and an injector support 12, and the proximal drive unit includes a closure cover 10b, a mechanical support 13, a needle protection spring 15, a switching sleeve 17, a locking sleeve 18, a drive and propulsion element, and a disposable loadable spring group 20 for automatic material output. During the emptying or assembly process, the prefilled injector is introduced into the injector unit and then the two subunits are assembled together, wherein the two housing parts 10a, 10b are non-releasably clamped together. The outer end of the helical spring 20a is anchored on the spring sleeve 20c or, in particular, if no spring sleeve is provided, on the mechanical support or directly on the closure cover. The spring flange can also be fastened to the spring sleeve, the mechanical support or the housing through its periphery.

[0043] The prefilled injector 11 includes a cylindrical injector body as a product container, and a hollow injection needle is fixedly connected to an injector shoulder at its distal end. The injection needle of the prefilled injector is covered by a needle guard 11a, which is constructed as a so-called rigid needle cover, Rigid Needle Shield (RNS) and includes a rubber elastic needle protection element and a shell made of hard plastic. The needle guard protects the injection needle from mechanical action and contamination and keeps the injection needle and the product sterile. An instrument cover or a pull-off cover 16 is arranged on the distal end of the automatic injector in its delivery state, which is axially pulled off and / or screwed off and completely removed together with the needle guard 11a before using the automatic injector. The injector support 12 includes two fingers, which are fastened to the support sleeve of the injector support at its proximal end and have axial abutment elements for the injector shoulder at their distal ends. The illustrated injector holder can be adapted to the diameter of the prefilled injectors to be accommodated with a nominal filling volume of 1.5 ml, 2.25 ml or 4 ml, so that when the injector size is changed, no parts of the autoinjector have to be replaced except for the injector holder, or at least the distal housing part 10a is the same for all injector sizes. In particular, for the smallest injector diameters, the fingers can be flexible and pushed radially apart by the needle guard when the prefilled injector is axially introduced. In order to accommodate narrower injectors, the injector holder can also be embodied in two parts or supplemented by an adapter, as disclosed in patent application PCT / EP2020 / 052127. PCT / EP2020 / 052127 is hereby fully incorporated into the present application by reference.

[0044] The helical spring 20a or the spring coil 20b puts the drive element 21 into a rotational movement and puts the push element 22 into a preferably purely axial push movement. For this purpose, the threaded element engages in a thread extending over the push-out stroke and having a variable thread pitch. The threaded element comprises a thread segment whose extension in the direction of rotation or circumferential direction is less than half a turn, wherein preferably, the side surfaces of the thread segment have different pitch angles, so that when the thread pitch changes as the rotation proceeds, another area of ​​the side surface of the thread segment is correspondingly contacted by the thread. The variable thread can have a larger pitch in the starting range of the push-out and a smaller pitch at the end, thereby resulting in a constant push-out force despite the reduction of the spring force, as disclosed in the patent application WO 2016 / 205961. WO 2016 / 205961 is hereby fully incorporated into the present application by reference.

[0045] The switching sleeve 17 is arranged in a form-fitting manner with the proximal end of the sleeve arm 14a of the needle guard sleeve 14 and with the distal end of the needle protection spring 15 and is at least partially surrounded by the latter. The switching sleeve 17 is preferably snap-fitted with the proximal end of the sleeve arm of the needle guard sleeve 14 or even constructed in one piece with it. Inside the switching sleeve 17 and coaxially with the switching sleeve 17, a locking sleeve 18 is arranged, which is coupled to the switching sleeve 17 via a serrated locking member 18a elastically mounted on an arm pointing in the distal direction so that the actuation movement of the needle guard sleeve 14 and the switching sleeve 17 also causes the locking sleeve 18 to move proximally. By an additional proximal locking stroke of the locking sleeve 18 relative to the switching sleeve 17 to the proximal end position, the locking member 18a is reliably released from the switching sleeve 17 for inward movement. By the elastic action of the arm, the locking member 18a engages the proximal edge of the autoinjector from behind or snaps into an axially fixed recess of the autoinjector and thus locks the locking sleeve 18 against distal movement. When the autoinjector is removed from the puncture site, the switching sleeve 17 is pushed in the distal direction onto the locking member 18a by the needle protection spring 15, so that in the locked position, the locking member engages the proximal edge of the switching sleeve 17 from behind by the spring action of the arm and locks or blocks the switching sleeve and the needle protection sleeve from moving again in the proximal direction.

[0046] In order to adjust the puncture depth within the range of 5 to 8 mm and in particular to shorten it, the proximal stop of the needle guard on the housing or the proximal stop of the switching sleeve on the mechanical support can be defined by a short axial rib or projection which is appropriately mounted on one of the two stop parts. In order to adapt the puncture depth in this way, at least one coupling element cooperating with the needle guard and / or a triggering element mounted on the switching sleeve is also axially adapted or replaced accordingly for the correct triggering of the ejection.

[0047] The injector holder 12 is preferably made of a transparent material so that the contents of the injector can be optically inspected through a viewing window 10c in the housing 10a. A magnifying glass, preferably formed in the region of the viewing window by a variable thickness in the material of the injector holder, allows the identification of suspended particles in the liquid and the determination of the state of the drug. In order to protect the liquid from sunlight, an overlong device cover can be provided which extends over the region of the viewing window up to the proximal half of the autoinjector.

[0048] In accordance with Figure 1 In a first variant, the automatic injector comprises a drive element or a rotating member in the form of a threaded rod 21a with an external thread, which extends at least over a length corresponding to the ejection stroke. The threaded rod 21a is coupled to the spring shaft 20b in a rotationally fixed manner or even constructed integrally therewith. The propulsion element in the form of a propulsion sleeve 22a has a threaded element for engaging in the external thread on the inner side at the proximal end, the threaded element comprising a threaded section having preferably fewer turns than the external thread, or a threaded section having an extension range of less than one turn, preferably less than half a turn in the direction of rotation. The propulsion sleeve 22a is fixed in the mechanical support 13 or the housing to prevent rotation by an axial groove or other deviation from the rotationally symmetrical outer side, so that the rotation of the drive element generated by the rotation spring 20a is converted into a linear propulsion movement. Alternatively, the push sleeve 22a can have an internal thread extending over a length corresponding to the push-out stroke, and the thread of the threaded rod 21a can be reduced to a threaded element for engaging in the internal thread, the threaded element comprising a threaded section having preferably fewer turns than the internal thread, or comprising a threaded section having a length of less than one turn, preferably less than half a turn. The coupling sleeve 23 has a hollow cylindrical body and a retaining element, which has two flexible retaining arms 23a installed in the distal direction, and at the ends of the retaining arms, there is a retaining cam 23b protruding radially inward. The spring coil 20b has a distal widening portion 20d, which includes a coil sleeve arranged concentrically with the spring axis, and the coil sleeve has a locking surface that acts tangentially and points radially outward against the rotation around the longitudinal axis on four molded portions distributed on the circumference of the coil sleeve. The locking surface can also be formed by a stamping portion on the periphery of the coil flange of the widening portion 20d arranged concentrically with the spring axis.

[0049] Figure 2 Shown through the Figure 1 , a longitudinal section of the autoinjector in the state ready for injection after the instrument cover has been removed, in which the injection needle 11b is laterally covered by the needle protection sleeve 14. Before ejection, the retaining projection 23b of the retaining element engages in the recess of the axially fixed mechanical support 13 and is prevented from moving outwards by the inner circumference of the locking sleeve 18, whereby the coupling sleeve 23 is also unable to move axially. When the ejection is triggered, the locking sleeve 18 is moved out of the position of the recess by the proximal movement of the needle protection sleeve 14, so that the retaining arm 23a can be radially loosened and the coupling sleeve 23 is released.

[0050] Figure 3 A cross section through the automatic injector before ejection is shown, axially at the height of the proximal end of the coupling sleeve. Figure 2 Indicated by an interrupted vertical line. Here, the connecting sleeve includes four protrusions 23c, which are offset by 90° and pointed inwardly, as a first connecting element, which are non-rotatably engaged in four corresponding recesses on the widened portion 20d at the distal end of the spring coil as a second connecting element via radially oriented locking surfaces 24a. At the same time, the four molded parts 23d of the connecting sleeve, which are evenly distributed on the circumference and pointed outwardly, are engaged in four recesses of the spring sleeve 20c assembled in the housing in a non-rotatable manner. The protrusions 23c and the molded parts 23d have an angular extension range of approximately 45°. In addition, the inwardly directed protrusions are offset relative to the outwardly directed molded parts, so that a more or less constant thickness of the connecting sleeve is obtained. As shown by Figure 3 It can be seen that the alternately arranged recesses / stampings of the coupling sleeve can also be mentioned at the positions of the alternately arranged protrusions / moldings of the coupling sleeve. Through these two engagements, the spring coil 20b is coupled to the housing 10b in a rotationally fixed manner, so that the threaded rod 21a and the advancing sleeve 22a also do not move.

[0051] Figure 4 A longitudinal section through the combination of the automatic injector is shown immediately after the ejection is triggered or at the beginning of the ejection. The section plane of the lower half corresponds to Figure 2The section plane of the upper half is rotated 60° about the longitudinal axis relative to the section plane of the upper half. The needle protection sleeve 14 is moved proximally by contact with the injection site and thereby also pushes the locking sleeve 18 in the proximal direction under the tension of the needle protection spring 15. Therefore, for the first loosening movement, the retaining arm 23a of the coupling sleeve 23 is released radially outward and the coupling sleeve can move axially. The proximal end of the needle protection spring 15 is supported on the coupling sleeve 23 and pushes it proximally with a coupling stroke, wherein in this variant, the coupling stroke is different from the actuation stroke of the needle protection sleeve 14. Preferably, the locking sleeve 18 is moved proximally relative to the switching sleeve 17 with a locking stroke corresponding to the coupling stroke by a radially outwardly directed protrusion on the retaining arm 23a until the first stop with the mechanical support 13. In the end position of the locking sleeve, the locking member 18a is engaged with the inwardly directed protrusion in the recess of the mechanical support and the distal movement of the locking element is made impossible, thereby activating the locking of the needle guard sleeve. If the first stop is not realized by the coupling sleeve 23 but by the locking sleeve 18, the coupling sleeve can be used for the final stroke until the second stop and therefore can be used for the end button of the machinery at the end of the push-out. For this reason, the retaining arm 23a is released radially inwardly by the end edge of the proximal end of the advancing sleeve 22a for the second loosening movement. Because the locking surface of the inner protrusion 23c of the coupling sleeve and the locking surface of the recess of the widening portion 20d of the spring coil each have an axial extension range or have an overlap less than the coupling stroke, the engagement of the protrusion of the coupling sleeve with the recess of the widening portion is loosened, and the spring coil begins to rotate under the effect of the torsion spring. The locking surface of the widened portion 20d of the spring coil is located on a stamped portion of the coil flange, which is offset from the distal spring flange in the distal direction at least by a coupling stroke, or on a molded portion on the coil sleeve, which is offset from the distal spring flange in the distal direction at least by a coupling stroke.

[0052] Figure 5 A longitudinal section through the combination of the auto-injector after injection is shown. The section plane of the lower half corresponds to Figure 2The section plane of the upper half is rotated 90° around the longitudinal axis relative to the section plane of the upper half. The needle protection sleeve 14 moves from the rear end position to the front end position by the needle protection spring when the automatic injector is removed from the puncture site in the fixed movement, thereby covering the injection needle 11b laterally. The radially inwardly directed protrusion on the elastic arm of the locking member 18a engages in the recess of the mechanical support 13, thereby preventing the movement of the locking sleeve 18 in at least the distal direction. The locking sleeve abuts against the distal end face of the mechanical support at the proximal end, so that the locking sleeve cannot move in the proximal direction. The radially outwardly directed protrusion on the elastic arm of the locking member 18a engages the proximal edge of the switching sleeve 17 from behind, so that the switching sleeve cannot move in the proximal direction either. The axially fixed locking of the locking sleeve can also be performed by a locking element or a clamping element different from the locking sleeve.

[0053] The internal and external embossing of the coupling sleeve and its corresponding counterpart can be different in structure, quantity and / or axial arrangement. For example, the profiled portion can take the form of an axial rib, and the recess on the spring coil or the spring sleeve is correspondingly designed as the form of an axial slit, or the profiled portion and the recess are both designed as teeth. The recess on the spring sleeve can also be directly mounted on the housing, and the corresponding connection can, but need not, also be loosened in the coupling stroke. Considering the disposable use and rotation prevention of the automatic syringe, the internal and external profiled portions of the coupling sleeve can also be designed to be different respectively, as long as only the axial extension and arrangement of the internal protrusion allow the coupling stroke to be loosened and the external profiled portion is compatible with the rotation orientation of the retaining arm of the coupling sleeve.

[0054] Figure 6 is an exploded view of the components of an automatic injector according to a second variant of the present invention. Figure 1The different components include a drive element in the form of a drive sleeve 21b, which is connected to the spring coil 20b in a rotationally fixed and axially fixed manner at the distal end of the torsion spring 20a or is even constructed integrally therewith. The drive sleeve has a threaded element at its distal end, which engages in the external thread of the piston rod 22b extending over a length corresponding to the ejection stroke. The threaded element includes a threaded section of an internal thread, which preferably has fewer turns than the external thread, or includes a threaded section with an extension in the rotational direction of less than one turn, preferably less than half a turn. The piston rod is located in the interior space of the drive sleeve and serves as an advancing element, and the piston rod has a longitudinal groove, into which the mechanical support 13 fixed to the housing engages, so that a purely axial forward movement of the piston rod is caused in a known manner by the rotational movement of the drive sleeve. Alternatively, the sleeve-shaped drive element can have an internal thread that extends over a length corresponding to the ejection stroke, and the thread of the threaded rod can be reduced to a threaded section with a small number of turns or a threaded section with less than one turn at the proximal end.

[0055] Figure 7 The device is shown in a state ready for injection after the device cover is removed. Figure 6 . The section plane of the lower half is rotated 90° about the longitudinal axis relative to the section plane of the upper half. The switching sleeve 17, which is pushed onto the proximal end of the needle protection sleeve 14 in the distal direction by the needle protection spring 15, is guided in a rotationally fixed manner in the mechanical support 13. The locking sleeve 18 is coupled to the switching sleeve 17 in a rotationally fixed manner. The drive sleeve 21b has a shaped portion in the form of two oppositely disposed axially oriented locking ribs 21c on its outer side as a second coupling element.

[0056] Figure 8 A cross section through the autoinjector is shown in the viewing direction at the distal end in the axial direction at the height of the shaped portion of the drive sleeve. Figure 7 The locking sleeve 18 comprises two locking grooves, into which the locking ribs 21c engage via the locking surfaces 24b and which prevent or block the drive sleeve from moving at least in the relaxation direction of the torsion spring (along the Figure 8 The viewing direction in the embodiment is along the counterclockwise direction) to prevent or stop the advancement of the piston rod 22b. The axial movement of the locking sleeve 18 when piercing with the coupling stroke corresponding to the actuation stroke in this variant is released, thereby releasing the engagement and releasing the drive sleeve for rotation.

[0057] As an alternative to the illustrated connection by means of two locking ribs / locking grooves, other shaped parts or projections on the drive sleeve can also be used as second connecting elements and engage in a rotationally fixed manner in a corresponding recess or embossing of the locking sleeve as a first connecting element, always assuming that the axial arrangement and extension of the locking surfaces are separated during the connecting stroke of the locking sleeve.

[0058] Fig. 9 A longitudinal section through the autoinjector is shown immediately after the ejection is triggered or at the beginning of the ejection. The needle guard sleeve 14 is moved proximally by contact with the injection site and thereby also pushes the switching sleeve 17 and the locking sleeve 18 in the proximal direction under the tension of the needle guard spring 15 and when the drive sleeve 21b is released as described.

[0059] The drive sleeve 21b can have a further shaped portion in the form of a pin or a cam, which as a first guide element engages in a second guide element in the form of a guide groove of the locking sleeve 18 after the coupling stroke. These guide elements act as a guideway control, so that an initial rotation of the drive sleeve causes the locking sleeve 18 to move further proximally relative to the switching sleeve 17 with a locking stroke into the end position of the locking sleeve, in which the locking of the needle guard is activated by the locking member 18a engaging with an inwardly directed protrusion into a circumferential groove of the axially fixed drive sleeve 21b. Fig. 9 , the locking sleeve can be seen in the axial end position assumed here, in which the locking sleeve is axially locked. The guide groove is not oriented parallel to the longitudinal axis of the autoinjector or is formed at an angle thereto or in the form of a helical segment.

[0060] Fig.10 A variant of the first guide element is shown in the form of an extension 21d in the proximal direction of the shaped part, which forms the locking rib 21c. The area of ​​the extension is angled relative to the longitudinal axis, correspondingly to the locking sleeve in the proximal direction of the shaped part. Figure 8 The locking groove shown in FIG is so wide that it can also accommodate the extension 21d as a second guide element. As soon as the end of the coupling stroke is approached, the axial locking rib 21c axially comes out of the locking groove and the locking surface is decoupled, and the drive sleeve 21b and the surface of the extension 21d that is angled relative to the longitudinal axis begin to rotate. As a result, the locking sleeve is further pushed in the proximal direction, especially relative to the switching sleeve, until the locking member of the locking sleeve is engaged behind the surrounding edge of the drive sleeve and the movement of the locking sleeve in the distal direction is not possible. The first angled guide element does not have to be directly attached to the locking rib 21c, but can also be offset in the circumferential direction and move in a separate guide groove that is different from the locking groove.

[0061] Fig.11 A longitudinal sectional view through the automatic injector after injection is shown. The needle protection sleeve 14 moves from the rear end position to the front end position by the needle protection spring in the fixed movement when the automatic injector is removed from the puncture site, thereby covering the injection needle 11b laterally. The locking member 18a engages with the radially inwardly directed protrusion on the elastic arm of the locking sleeve in the surrounding recess of the drive sleeve 21b, thereby preventing the movement of the locking sleeve in at least the distal direction. The locking sleeve abuts against the distal end face of the spring sleeve 20c at the proximal end, so that the locking sleeve cannot move in the proximal direction either. The radially directed protrusion on the elastic arm engages the proximal edge of the switching sleeve 17 from behind, so that the switching sleeve cannot move in the proximal direction either.

[0062] Reference numerals list

[0063] 10a Housing

[0064] 10b Enclosed hood

[0065] 10c concave part

[0066] 11 Pre-filled injector

[0067] 11a needle protection cover

[0068] 11b injection needle

[0069] 12 Injector bracket

[0070] 13 Mechanical support

[0071] 14-pin protection sleeve

[0072] 14a Arm

[0073] 15-pin protection spring

[0074] 16 Equipment cover

[0075] 17 Switch sleeve

[0076] 18 Locking sleeve

[0077] 18a Locking member

[0078] 20 Spring Set

[0079] 20a coil spring

[0080] 20b spring coil

[0081] 20c spring sleeve

[0082] 20d widening part

[0083] 21 driving components

[0084] 21a Threaded rod

[0085] 21b drive sleeve

[0086] 21c Forming Department

[0087] 21d guide element

[0088] 22 propulsion element

[0089] 22a Push sleeve

[0090] 22b piston rod

[0091] 23 Connecting sleeve

[0092] 23a Holding arm

[0093] 23b Retaining tab

[0094] 23c protrusion

[0095] 23d molding department

[0096] 24 locking surface.

Claims

1. An automatic injector comprising a housing, a product container axially fixed in the housing, a torsion spring, a drive element (21), a thrust element (22) and a needle protection sleeve (14), wherein: When the automatic injector is pressed onto the injection site, the needle guard (14) performs an actuation movement in the proximal direction, and wherein, in order to push the liquid from the product container through the injection needle (11b) into the injection site, the torsion spring causes the drive element (21) to rotate, and the rotating drive element causes the propulsion element (22) and the piston in the product container to move in the distal direction, characterized in that the automatic injector includes a coupling part, which does not include the propulsion element (22), and the coupling part releases the drive element (21) for rotation due to the actuation movement of the needle guard (14), wherein the coupling part includes a first coupling element, which is engaged in a second coupling element via a locking surface, wherein the engagement can be released by an axial coupling stroke of the two coupling elements.

2. The automatic injector according to claim 1, characterized in that The engagement can be released by an axial coupling stroke which corresponds at least to the penetration depth of the injection needle (11b).

3. The automatic injector according to claim 1 or 2, characterized in that: The advancing element (22) has an axial guide element for a purely linear advancing movement in the housing.

4. The automatic injector according to claim 3, characterized in that The drive element comprises a threaded rod (21a), and the thrust element comprises a thrust sleeve (22a).

5. The automatic injector according to claim 1 or 2, characterized in that: The coupling comprises a coupling sleeve (23) having the first coupling element, which radially engages in a second coupling element which is connected to the drive element (21) in a rotationally fixed manner.

6. The automatic injector according to claim 5, characterized in that The coupling sleeve (23) has a retaining element which is released by the actuating movement of the needle guard (14), and the autoinjector has a spring which subsequently moves the coupling sleeve (23) axially relative to the second coupling element during a coupling stroke.

7. The automatic injector according to claim 5, wherein: One end of the torsion spring is coupled to the spring coil (20b) in a rotationally fixed manner, and a spring flange defines a receiving area of ​​the torsion spring at the distal end, characterized in that the second connecting element is arranged on the widened portion (20d) of the spring coil (20b) and is spaced apart from the distal spring flange by at least the length of the connecting stroke.

8. An automatic injector according to claim 1 or 2, comprising a locking sleeve (18) having a locking member (18a) for locking the needle protection sleeve (14) in the needle protection position at the end of an injection, characterized in that The first coupling element is arranged on the locking sleeve (18).

9. The automatic injector according to claim 8, characterized in that The drive element comprises a drive sleeve (21b), and the thrust element comprises a piston rod (22b), and the second coupling element is arranged on the drive sleeve (21b).

10. The automatic injector according to claim 9, characterized in that The drive sleeve (21b) and the locking sleeve (18) have a slotted guide having a first guide element and a second guide element, the slotted guide being designed such that an initial rotation of the drive sleeve (21b) pushes the locking sleeve (18) in a proximal direction with a locking stroke.

11. The automatic injector according to claim 1 or 2, characterized in that: The first coupling element and the second coupling element comprise at least two locking surfaces on the shaped part or the corresponding recess.

12. An automatic injector according to claim 1 or 2, comprising a rotation sensor for detecting at least one rotational position per revolution of the drive element during ejection, and a processor unit for determining the axial piston position of the piston in the product container from the detected rotational position.

13. The autoinjector according to claim 12, comprising a communication unit for communicating with a third device and / or a display unit for displaying the status of the autoinjector.

14. A drive unit for an automatic injector, comprising a closure cap (10b), a torsion spring for ejecting the maximum content of a product container axially fixed in the automatic injector at one time, a drive element (21) and a propulsion element (22), wherein: In order to push the liquid out of the product container, the torsion spring rotates the drive element (21), and the rotating drive element causes the propulsion element (22) and the piston in the product container to move in the distal direction. The drive unit comprises a coupling having a first coupling element, which is engaged in a second coupling element via a locking surface, wherein the engagement can be released by an axial coupling stroke of the two coupling elements and the drive element (21) can be released for rotation.

15. The drive unit according to claim 14, characterized in that The coupling stroke is achieved by an actuating movement of the needle guard of the autoinjector and corresponds at least to the penetration depth of the injection needle.

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