WO2008113198A1 - Injection device with controlled needle retraction - Google Patents

Abstract

The invention relates to an injection device, especially autoinjector, which comprises: a) a housing (1), b) an actuating sleeve (6) which is mounted to be movable relative to the housing (1) and which can be placed on a point of injection of a patient with the distal end of the injection device, c) an injection needle (4) which protrudes over the distal end of the injection device when in the position of insertion and which can be moved back into the interior of the injection device, d) an actuating cam (17) which is arranged in an axially fixed manner relative to the injection needle (4) and which engages in a locking recess (20) when in the position of insertion to prevent the injection needle (4) from being retracted into the interior of the injection device, e) said actuation cam (17) being releasable from the engagement with the locking recess (20) by means of the actuating sleeve (6), thereby releasing the injection needle (4) for the retracting movement.

Description

 Injection device with controlled needle retraction

The invention is in the field of injection devices for administering a liquid product, in particular medicament. The invention relates to an injection device and a method for the controlled withdrawal of a needle from a puncture position.

In injection devices, in particular auto-injectors, it is known to inject a needle through the mechanism of the device into a patient and then to dispense the product through the needle into the patient. After the product has been dispensed, the needle is pulled back into the injection device.

For example, US Pat. No. 6,387,078 B1 discloses an injection device in which a needle is inserted first with the aid of a propulsion spring and then the product is discharged with this propulsion spring. When propulsion through the propulsion spring at the same time a return spring is tensioned. Immediately upon reaching the final position of a dispensing movement, the propulsion spring is decoupled from the return spring so that the return spring immediately retracts the needle into the housing. It may happen that the drug is not completely injected into the tissue of the patient, so that a small amount is lost. Especially with expensive drugs, this is annoying. Also with regard to the dose actually administered, the lost residue can lead to problems.

The object is therefore to provide an injection device and a method in which the patient can easily determine when the needle is retracted.

The object is solved by the features of the independent claims 1 and 15. Advantageous further developments emerge from the dependent claims.

The injection device may, for example, be adapted to dispense a product from a product container. The injection device is preferably a so-called autoinjected gate, in which a mechanism is provided which allows an automatic insertion of the injection needle and subsequent product release. After the product has been dispensed, the needle should be pulled back into the injection device.

The injection device comprises a housing. The housing has a distal and a proximal end. The distal end is the end where the needle is located. The proximal end is the end opposite the distal end.

The device further comprises an actuating sleeve which is movably mounted relative to the housing. The actuator sleeve is attachable to the distal end of the injection device at an injection site of the patient. Preferably, the actuating sleeve over the distal end of the housing over a small piece. The small piece should be sized so that when switching the actuating sleeve to this small piece in the proximal direction and back in the distal direction necessary switching operations can be performed. For example, when moving in the proximal direction, this may be the initiation of a puncture and, when moving back in the distal direction, the initiation of the return motion for the needle. In particular, an elasticity agent, such as e.g. a spring element or a spring can be provided, which can be tensioned in the proximal direction by the movement of the actuating sleeve and / or with which the actuating sleeve can be driven for the movement in the distal direction. The elasticity agent therefore has a restoring character and can be referred to as a return spring, for example. The elasticity means preferably serves to return an actuating sleeve, which is not sufficiently moved back into the proximal direction to trigger a switching operation, back into the starting position and / or to assist in a switching operation which is caused in the distal direction when the actuating sleeve is moved.

Preferably, the actuating sleeve can be pushed from its most distal position so far in the proximal direction that its distal end is approximately flush with the distal end of the housing, which corresponds to the state in which the user set the Inj ektions device to the injection site of the patient and pressed Has.

The device further comprises an injection needle which protrudes beyond the distal end of the injection device in a puncture position. The injection needle can be attached to a nem product container, in particular at its distal end, be arranged. At least the injection needle is fluidly connected to the interior of the product container. Inside the product container is the administered, especially liquid product. This product may be a hormone, such as growth hormone, or diabetes insulin, or another medicine. The product container is closed at its proximal end with a piston arranged displaceably relative to the product container. Movement of the piston towards the distal end of the product container dispenses the product through the needle. Preferably, the needle is axially fixed to the product container.

Preferably, the injection needle and in particular also the product container are arranged displaceably relative to the housing along the longitudinal axis of the injection device. For example, For example, the injection needle can be moved into the puncturing position from a starting position in which it is located, in particular, completely in the distal end of the injection device, i.e., does not protrude beyond the distal end of the device. In the puncture position, the needle projects beyond the distal end of the device by a distance corresponding to the depth of injection of the needle into the tissue of the patient. Preferably, the injection needle is retractable from the puncturing position, in particular after a product has been dispensed, again, preferably completely into the distal end of the injection device, that is, into an end position of the injection needle. In the final position but also in the starting position, there is the advantage that you can not sting unintentionally through the needle.

Furthermore, the device comprises a switching cam, which is arranged axially fixed to the injection needle and engages in the piercing position of the needle in a locking window. The engagement serves, in particular, to prevent a retraction movement of the injection needle into the interior of the injection device. This is particularly desirable if a product distribution has not yet been completed. Preferably, the switching cam is indirectly connected to the injection needle. For example, the switching cam may be formed on a holder for the product container, which is preferred, or on the product container. In particular, the switching cam may be formed on a part of the propulsion structure, which comprises, for example, at least the product container and the holder for the product container. Preferably, the switching cam is resiliently formed on a part of the propulsion structure. For example, the switching cam is resiliently connected via an elastic arm to the part of the propulsion structure. specially connected in one piece. However, this should not rule out other resilient arrangements.

The locking window is preferably located radially outward from the switching cam. In particular, the switching cam can engage with a radially outward movement in the locking window. Preferably, the locking window with two relatively movable parts is distally and proximally limited. In particular, the housing or a housing-fixed element limit the locking window distally and the actuating sleeve the locking window proximally.

Furthermore, it is preferred that the width of the locking window facing in the longitudinal direction of the injection device is variable, so that depending on the width of the locking window of the switching cam is movable into engagement with the locking window or out of engagement with the locking window is movable. In other words, the width of the lock window is dynamic. Thus, for example, the locking window may disappear completely when its distal and proximal boundaries abut each other.

According to the invention, the switching cam can be moved by means of the actuating sleeve out of engagement with the locking window. As a result, the injection needle is released for the retraction movement from the puncture position to the end position. Since the user of the device can control the position of the actuating sleeve in a manner dependent on the contact pressure of the injection device to the injection site, he can thus determine the point in time at which the injection needle is drawn into the housing. For this purpose, the user of the device only needs to reduce the contact pressure of the injection device to the injection site. In particular, this causes the actuating sleeve to move in the distal direction.

Particularly preferably, the actuating sleeve is moved out of engagement with the locking window with the movement of the actuating sleeve in the distal direction. In particular, this movement reduces the width of the blocking window pointing in the longitudinal direction of the injection device, and in particular eliminates the fact that the switching cam is moved out of engagement with the blocking window.

The advantage of voluntary control of the time of needle withdrawal is that the user of the device can determine himself, in particular on the basis of experience. or how long the needle should remain in the tissue after product dispensing for complete product release, depending on the viscosity of the fluid. A fist value, which is given only as an example, is a duration of 5 seconds. This waiting time can ensure that the liquid product in the tissue is better distributed and that the product has been completely released due to the inertia of the product distribution. On the one hand, this offers economic advantages and, on the other hand, advantages in determining the actual dose of product administered.

Preferably, in order for the needle retraction to occur, at least two prerequisites should be satisfied, namely that the product dispensing has ended and the actuating sleeve has been moved in the distal direction.

Preferably, the switching cam has a stop surface facing in the proximal direction, which can cooperate with the actuating sleeve so that the switching cam can be taken from the actuating sleeve in a distal movement of the actuating sleeve when the switching cam is in the locking window. Therefore, it is also preferred that a movement of the switching cam in the proximal direction is locked when the stop surface of the switching cam with the proximal boundary of the locking window is in a stop. This prevents the needle and in particular the entire propulsion structure from being displaced in the proximal direction.

In particular, the switching cam can be shaped in the distal direction so that it is movable from the housing or the housing-fixed element out of engagement with the locking window and / or that it can be moved by the actuating sleeve out of engagement with a recess formed by the actuating sleeve , For example, such a shape may be an obliquely facing inclined surface that moves the switching cam out of the locking window in accordance with the principle of an inclined plane. Preferably, the movement with which the switching cam is moved out of engagement with the locking window, a radial, in particular a radially inwardly directed movement of the control cam.

In particular, in the starting position of the device, the switching cam can be in engagement with a recess formed by the actuating sleeve. This recess is preferably arranged proximally of the locking window. The recess will both delimited distally and proximally from the actuator sleeve. The recess can be a breakthrough or a pocket. Preferably, the switching cam can be brought out of engagement with the recess with a movement of the switching cam in the distal direction, as is the case for example in the movement of the needle from the starting position to the piercing position.

In particular, it is preferred that the switching cam is located in a retracted position in the distal end of the injection device, in particular the starting position and / or the end position of the injection needle, in engagement with the recess formed proximally of the locking window.

Preferably, the housing or a housing-fixed element has a radially inwardly facing Abragung, which engages so far in an opening formed by the wall of the actuating sleeve, that the radially inwardly facing inner surface of the Abragung approximately flush with the radially inwardly facing inner surface of the Actuating sleeve is. In particular, this projection forms the distal boundary for the blocking window. Due to the flush nature of the inner surfaces, the locking cam can slide smoothly from the inner surface of the projection onto the inner surface of the actuating sleeve, such as e.g. the case is when the needle is moved from the puncture position to the end position. The lock window is closed, d. e., that its proximal boundary abuts the distal boundary, so that the window width is zero.

Particularly preferably, the switching cam is coupled to a return spring, with which the switching cam and the axially fixedly connected injection needle and in particular the entire propulsion structure, are movable in the proximal direction. In particular, the switching cam is indirectly coupled to the return spring, such as e.g. via the holder for the product container and a functional sleeve against which the return spring, in particular with its proximal end, is supported. In particular, the holder and the functional sleeve can be axially fixed to each other so that they can behave like a single part.

Preferably, the return spring is a helical compression spring which can be prestressed in the distal direction with a movement of the functional sleeve and can be relaxed in the proximal direction with a movement of the functional sleeve. Particularly preferred is the return spring of a Vortriebsfeder prestressed. The propulsion spring can be used for propelling the needle from the starting position into the piercing position and preferably also for product dispensing. In preferred embodiments, therefore, a single propulsion spring is sufficient.

In preferred embodiments, the injection device may comprise a blocking element which is fixedly connected to the switching cam via the driving structure. In particular, the blocking element is connected via the functional sleeve and the holder for the product container with the switching cam. As a result, the blocking element and the switching cam have a fixedly defined axial distance from each other, which is not changed during the entire switching operation in the injection device. The blocking element can be movable in the puncturing position of the injection needle into engagement with the recess formed proximally of the locking window of the actuating sleeve. In particular, the blocking element can be moved upon completion of the piercing into engagement with the recess. As a result, the injection needle is blocked for withdrawal from the puncture position in the proximal direction. In particular, the blocking element can release a locking engagement with a piston rod acting on the piston during movement into the engagement, thereby simultaneously driving the piston rod for a dispensing movement of the advancing spring.

Furthermore, the return spring can be decoupled from the propulsion spring by the movement of the locking element into engagement with the recess after the propelling spring has biased the return spring during the plunge movement.

Particularly preferably located in the piercing position of the needle and in particular before a complete product distribution, ie, during the dispensing movement, the switching cam in engagement with the locking window and the locking element in engagement with the recess formed by the actuating sleeve. During this state of the injection device, there is a small distance, in particular from 0.3 to 3 mm, between the proximal boundary of the blocking window and the stop surface of the switching cam facing in the proximal direction. The blocking element is in this case with its pointing in the proximal direction stop surface in contact with the proximal boundary of the recess of the actuating sleeve. Particularly preferred is the axial distance between the pointing in the proximal direction stop surface of the control cam and the in proximal direction facing stop surface of the locking element prevails, larger, in particular by the small distance greater than the axial distance between the proximal boundary of the recess of the actuating sleeve and the proximal boundary of the locking window. By the mentioned small distance a haptic, in particular tactile, or acoustic signal can be generated which indicates the completion of the product distribution. It is preferred that the propulsion structure, and thus the blocking element and the switching cam of the return spring by the amount of the small distance in the proximal direction is movable. As a result, the stop surface of the switching cam pointing in the proximal direction abruptly abuts against the proximal boundary of the locking window, whereby the signal is generated.

Preferably, after completion of the product dispensing, the locking member may disengage from the recess, allowing the return spring to relax by the small distance to produce the signal. It is particularly preferred that disengagement of the locking element from the engagement with the recess is blocked, in particular by the outer peripheral surface of the piston rod moving past the blocking element.

The invention further relates to a method for drawing an injection needle extended from the distal end of the injection device into the distal end, whereby the actuating sleeve moves out of the distal end of the injection device and thereby a locking cam engaging in a locking window is carried along by the actuating sleeve. During the driving movement, the switching cam is moved out of the locking window. The switching cam firmly connected to the injection needle is moved in the proximal direction, so that the extended injection needle is retracted into the distal end of the injection device. The process is complete, d. H. with all its procedural steps, outside the human or animal body feasible.

Advantageous method steps result from the operation of the device.

The invention will now be described with reference to figures. The features disclosed in the figures form the invention individually and in combination with the features described above, the invention advantageously further. Show it:

FIGS. 1 a and 1 b show a sectional view of an injection device according to the invention with an attached cap, wherein FIG. 1 b is a view rotated by 90 ° relative to FIG. 1 a, about the longitudinal axis;

2a and 2b are sectional views of the injection device with a cap removed, wherein FIG. 2b is a view rotated by 90 ° with respect to FIG. 2a about the longitudinal axis;

FIGS. 3a and 3b show sectional views of the injection device according to the invention in an activated state, FIG. 3b being a view rotated by 90 ° with respect to FIG. 3a about the longitudinal axis,

4a and 4b are sectional views of the injection device according to the invention in a triggered state, Figure 4b is compared to Figure 4a rotated by 90 ° about the longitudinal axis view, Figures 5a and 5b are sectional views of the injection device according to the invention in a eingochenenen state, Figure 5b a comparison with FIG 5a is a view rotated 90 ° about the longitudinal axis,

6a and 6b are sectional views of the injection device according to the invention in a dispensed state, wherein FIG. 6b is a view rotated by 90 ° with respect to FIG. 6a about the longitudinal axis;

7a and 7b are sectional views of the injection device according to the invention in a state in which the injection device has delivered a signal indicating the end of the payout clicking sound, Figure 7b is compared to Figure 7a rotated by 90 ° about the longitudinal axis view,

8a and 8b are cross-sectional views of the injection device according to the invention in which a retraction of the injection needle is activated, wherein FIG. 8b is a view rotated with respect to FIG. 8a by 90 ° about the longitudinal axis,

9a and 9b are sectional views of the injection device according to the invention in a final state, wherein FIG. 9b is a view rotated by 90 ° with respect to FIG. 9a about the longitudinal axis;

FIG. 10 shows a sectional representation of the signaling unit from FIGS. 1 to FIG. 11 is a perspective view of the signaling unit of FIG. 10;

FIG. 12 shows an injection device according to the invention with another embodiment of a signaling unit,

13 shows a sectional view of the signaling unit from FIG. 12, FIG. 14 shows a further sectional view of the signaling unit from FIG. 12, and FIG

Figures 15 and 16 show a further embodiment of a signaling unit according to the invention.

Unless otherwise indicated, like reference numerals designate the same parts.

FIGS. 1a, 1b to 9a, b show an injection device of a preferred embodiment. With particular reference to FIGS. 1a and 1b, the injection device has a housing 1 which consists of a proximal housing part 1a and with the proximal housing part with a latching connection Ic axially fixed, distal housing part Ib. The latching connection Ic is formed from a window contained in the proximal housing part, in which an elastic tongue formed by the distal housing part Ib is snapped.

In the housing 1, a product container 2 is accommodated, at the distal end of which an injection needle 4 for dispensing a liquid product contained in the product container 2 is located. At the proximal end, the product container 2 has a displaceable piston 3, the movement of which causes a product discharge relative to the product container 2 and in the direction of the injection needle 4, for which reason it is also possible to speak of a dispensing movement. The product container 2 is received in the device such that it is displaceable in the distal direction, so that the injection needle 4 emerges from the distal end of the injection device. Therefore, here can be talk of a plunge. The product container 2 is axially fixedly connected to a holder 10 for the product container 2. The housing 1, in particular its distal and proximal housing parts Ia, Ib have a viewing window 12, through which the user of the injection device can take a look at the product container 2. The holder 10 surrounds the product container 2 in a sleeve shape, so that, in order to reveal the view of the container 2, it either itself has a viewing window or, as in this example, a transparent material. The product container 2 is provided with a functional sleeve 11 arranged proximally at the proximal end thereof the bracket 10 formed axially fixedly connected. The product container 2 has at its proximal end a radially projecting collar which is grasped by the clamp. The functional sleeve 11 has at its distal end on a radially projecting collar, which is also encompassed by the clip. Thus, product container 10, functional sleeve 11 and holder 10 are axially fixed together, so that they can be moved as a single part. In the following, this combination is referred to as a propulsion structure 2, 10, 11.

The functional sleeve 11 surrounds a piston rod 5, which can act on the piston 3 for a product discharge. The piston rod 5 has a sleeve-shaped part, which surrounds a propulsion spring 6, wherein the propulsion spring 6 is supported distally on the piston rod 5 and proximally on a switching sleeve 8, in particular on a base 8a formed thereon.

A signaling unit is arranged on the piston rod 5, with which one, preferably at least three or more haptic and / or acoustic signals can be generated for the piercing process and / or the dispensing process. The signaling unit comprises a connected to the switching sleeve 8 grid rod 23 and a surrounding the grid bar 23 engaging sleeve 22 which is axially fixedly connected to the piston rod 5, in particular latched. The engagement sleeve 22 has an engagement element 26 which engages in a groove 27 formed by the grid bar 23. The grid rod 23 has at its proximal end a head 24 which is movable in a direction formed by the activation element 13 sliding guide 25 in the proximal direction. The head is with its distal end in engagement with a base 8a formed by the shift sleeve 8, wherein the engagement prevents the head 24 and thus the grid bar 23 in the distal direction relative to the shift sleeve 8 is movable. The exact operation of this arrangement will be explained later with reference to Figs. 10 and 11, in which the signaling unit shown in Figs. 1 to 9 is shown in detail. Alternatively, the signaling unit of FIGS. 10 and 11 may be replaced by another signaling unit according to FIGS. 12 to 14 and yet another signaling unit according to FIGS. 15 and 16. The injection device shown in FIGS. 1 to 9 need not be substantially changed for this purpose.

In the initial state of the injection device shown in FIGS. 1a and 1b, the advancing spring 6 is prestressed, so that it supports the needle 4 and in particular the propulsion structure 2, 10, 11 drive for a piercing movement and can move the piston 3 for a Ausschüttbewegung. The functional sleeve 11 has a blocking element 16 on which a radially inwardly directed shoulder is formed, which in the initial state interacts with a shoulder projecting radially outward at the distal end of the piston rod 5, so that the piston rod 5 is relatively movable for movement is locked to the functional sleeve 11. The blocking element 16 is held by a radially inwardly facing surface of the switching sleeve 8 in engagement with the piston rod 5. Preferably, the blocking element 16 is connected via a spring arm elastically connected to the functional sleeve 11, in particular in one piece. The resilient arrangement may be configured such that the blocking element 16 tends to move radially outwards, this being prevented by the radially inwardly facing surface of the switching sleeve 8.

The functional sleeve 11 has at its proximal end at least one snap element 15, which snaps in the initial state to prevent movement of the functional sleeve 11 and thus the propulsion structure 2, 10, 11 in the shift sleeve 8. As a result, the prestressed spring 6 can not yet relax and the propulsion structure 2, 10, 11 does not yet move in the distal direction.

The injection device has at the proximal end of its housing 1 an activation element 13, which is axially fixed and rotatable to the housing 1. The activation element 13 receives a return spring 21, which is supported distally at the proximal end of the shift sleeve 8 and proximally to the activation element 13. The return spring 21 has the task of applying the switching sleeve 8 and an axially acting on the switching sleeve 8 actuating sleeve 9 with a force acting in the distal direction, so that switching sleeve 8 and actuating sleeve 9 are pressed in the distal direction. The activation element 13 has an activation safeguard 14 which, in the switching states of the injection device shown in FIGS. 1a, 1b and 2a, engages behind the snap element 15 such that the snap element 15 is blocked or secured for movement out of engagement with the shift sleeve 8 is. Thus, an accidental triggering of the injection device can advantageously be prevented. By rotation of the activation element 13 z. B. by 90 ° relative to the housing 1, the activation fuse can be moved out of engagement with the snap element 15. A return spring 7 acting in the longitudinal direction of the device is distally supported on the shift sleeve 8 and proximally on the functional sleeve 11. As shown in this example, the return spring 7 surrounds the shift sleeve 8 and the functional sleeve 11. The return spring 7 is supported proximally, in particular on a collar 11a formed by the functional sleeve 11, which protrudes radially outwardly through an opening formed in the shift sleeve 8 attacks. In certain switching positions, therefore, the return spring 7 can cause a relative movement between the shift sleeve 8 and the functional sleeve 11. The return spring 7 is a compression spring, which can move the functional sleeve 11 relative to the switching sleeve 8 in the proximal direction. The return spring 7 is not or preferably biased only with a slight preload. For example, in the state of the injection device shown in Figures Ia and Ib, the biasing force of the return spring 7 is less than the biasing force of the propelling spring. 6

Distal to the shift sleeve 8, the actuating sleeve 9 is arranged relative to the housing 1 movable. The shift sleeve 8 and the actuating sleeve 9 can each act on each other with a compressive force, in particular be locked together and thereby move. So that the actuating sleeve 9 does not block the view of the product container 2, it also has a window in the region of the window 12. Alternatively, the actuating sleeve 9 may be formed of a transparent material. The actuating sleeve 9 is advanced in the initial state of the return spring 21 via the switching sleeve 8 distally over the distal end of the housing 1. The distal end of the actuating sleeve 9 serves to be attached to an injection site of a patient.

The holder 10 has a switching cam 17 which engages in a recess 18 of the actuating sleeve 9, which, as shown in this example, may be an opening. The switching cam 17 is elastic with the holder 10, such. B. via a resilient arm, in particular integrally connected. The switching cam 17 is preferably biased to tend to engage the recess 18 or to move radially outwardly. The radially projecting from the holder 10 outwardly switching cam 17 has distally an oblique surface, which can help to push the switching cam 17 out of engagement with the recess 18. Furthermore, the switching cam 17 proximally a transversely, in particular perpendicular to the longitudinal direction stop surface, which with the proximal boundary of Recess 18 may get into an axial stop, by the switching cam 17 can not be moved out of the recess 18.

The actuating sleeve 9 has an axial stop 19, on which the distal end of the holder 10 can abut at the end of a piercing movement.

At the distal end of the injection device, as shown in Figures Ia and Ib, a cap 32 is arranged, which protects the interior of the injection device from contamination, in particular the needle 4 keeps sterile. Before using the injection device, the cap 32 is pulled off, so that in particular the needle 4 and the actuating sleeve 9 are exposed, as shown in FIGS. 2a and 2b. The state of the injection device shown in Figures 2a and 2b differs from the state shown in Figures Ia and Ib only in that the cap 32 is removed.

The force exerted at the withdrawal of the needle cap 32 on the injection device is passed through the holder 10 on the functional sleeve 11 and there passed over the snapper 15 on the shift sleeve 8, which is supported on the actuating sleeve 9. The actuating sleeve 9 is in turn latched to the housing 1 via a projection Id formed by the distal housing part 1, so that the removal of the cap 32 from the injection device does not have any undesired effect on the mechanism.

In the switching state shown in Figures 2a and 2b, the actuating sleeve 9 can not or only very slightly be pushed into the distal end of the Inj ektions device, since this sliding movement is forwarded via the switching sleeve 8 to the snapper 15, wherein the snapper 15 at a Movement in the proximal direction is prevented by the activation element 13.

In FIGS. 3a and 3b, the injection device is shown in an activated state, ie, that the injection device can be triggered. The injection device is activated or unlocked with a rotary movement of the activation element 13, for example. B. by 90 °. Here, the snap elements 15 are released for a radially inwardly directed movement characterized in that the activation fuse 14 moves out of engagement with the snap elements 15, in particular is rotated. Thus, there is room for the snap elements 15 after to be deflected inside. Furthermore, the activation element 13, like the snap element 15, has an activation cam 13a, which is brought into axial alignment with the snap element 15 by the rotational movement of the activation element 13. The snap element 15 has proximally and the activating cam 13a arranged proximally thereof has distally a contour which, during the movement of the snap element 15 in engagement with the activation cam 13, can deflect the snap element 15 radially inwards. In this example, the contours are two sloping planes sliding off each other.

To trigger the injection device, the user of the device places it with the distal end on the preferably previously disinfected injection site. As a result, the actuating sleeve 9 is displaced relative to the housing 1 in the proximal direction, preferably so far until the distal end of the actuating sleeve 9 is approximately flush with the distal end of the distal housing part Ib. By the movement of the actuating sleeve 9, the switching sleeve 8 is taken in the proximal direction, wherein the snap elements 15 by means of the activation cams 13 a from the engagement with the switching sleeve 8 are pressed in particular radially inwardly. With the movement of the actuating sleeve 9 in the distal direction, as long as the snap elements 15 are snapped into the switching sleeve 8, and the elements of the propulsion structure 2, 10, 11 taken in the proximal direction. Since the piston rod 5 with the functional sleeve 11 is in a locking engagement, the piston rod 5 is also entrained in the proximal direction. Likewise, the signaling unit received in the piston rod 5 is entrained in the proximal direction. The head 24 formed proximally on the grid bar 23 can slide along in the guide 25 formed by the activation element 13.

Since no relative movement between the activation sleeve 11 and the shift sleeve 8 can take place during this movement, neither the return spring 7 nor the advance spring 6 are relaxed or relaxed.

The force that the user of the device has to exert on the housing 1, so that the actuating sleeve 9 is displaced in the proximal direction, essentially determined by the force of the return spring 21, against which the switching sleeve 8 and the actuating sleeve 9 are moved. The spring 21 is preferably a compression spring and formed from a plastic material. Alternatively, of course, springs made of a spring steel material or a Another spring material can be used. The axial attachment of the activation element 13 to the housing 1 is in the form of a Ringschnappverbindung with the housing. If the actuating sleeve 9 is not pressed sufficiently far onto the injection site, so that the snap elements 15 are not disengaged from the switching sleeve 8, a reset of the triggering mechanism, eg the switching sleeve 8 and the actuating sleeve 9, takes place when the injection device is removed from the injection site the return spring 21st

As can be seen from FIG. 4b, the movement of the actuating sleeve 9 in the proximal direction forms a blocking window 20, which is delimited distally from the housing 1, in particular the projection Id and proximally from the actuating sleeve 9. Since no relative movement between the propulsion structure 2, 10, 11 and the actuating sleeve 9 takes place during the movement of the actuating sleeve 9 in the proximal direction, the switching cam 17 remains in the recess 18.

After the snapper 15 are disengaged from the engagement with the shift sleeve 8, the propulsion spring 6 can relax partially, whereby the propulsion structure 2, 10, 11 is displaced in the distal direction. In this case, the injection needle 4 protrudes beyond the distal end of the injection device. Since the functional sleeve 11 is moved relative to the switching sleeve 8 in this piercing movement, the return spring 7 is compressed, i. curious; excited. The spring force of the propulsion spring 6 is during the entire piercing operation, i. also at the beginning and at the end of the piercing operation greater than the spring force of the return spring 7. This has e.g. the advantage that the piercing force is reduced, which helps to protect the injection device.

As can be seen from FIGS. 5a and 5b, in which the situation at the end of the piercing device is shown, the blocking element 16 engages in the recess 18 with a radially outwardly directed movement, as should be shown with the arrows in FIG. 5b , In order to improve this engagement, the blocking element 16 has a radially outwardly directed projection. The blocking element 16 fulfills a dual function. When the blocking element 16 engages in the recess 18, the blocking element 16 simultaneously disengages with the radially outwardly directed movement out of the piston rod 5, so that it is released for a dispensing movement. In return, the movement of the drive structure 2, 10, 11 is locked in the axial direction, in particular in the proximal direction. Through this process will the feed spring 6 decoupled from the return spring 7, that is, that the feed spring 6 in this state has no influence on the bias of the return spring 7. This is followed by a dispensing movement in which the signaling unit dispenses a time-constant clicking sound which can also be felt by the user of the device.

For the user of the device, no additional force is felt by the piercing process. This is caught by the Verschnappung between the actuating sleeve 9 and the shift sleeve 8 and is not supported on the housing. The force for the plunge process is conducted via the functional sleeve 11 to the collar of the product container 2. Thus, the piercing process is forcibly controlled, since the functional sleeve 11 advances the product container 2 until the end of the discharge and the piston rod 5 can dispense into the recesses 18 only after the engagement of the blocking elements 16. The piercing movement is stopped by the stop 19 on the actuating sleeve 9.

In the puncture movement of the switching cam 17 is pressed due to its distal configuration of the distal boundary of the recess 18 of the actuating sleeve 9 out of engagement with the recess 18 and displaced in the distal direction so that it locks in the locking window 20, as shown in Figures 5a and 5b is shown. The locking element 16 latched into the recess 18 is in contact with the proximal boundary of the recess 18. Since the locking element 16 and the switching cam 17 are due to their axially fixed arrangement to each other at a defined distance, it is preferred that in a recess engaging with the blocking element 16 between the proximal end of the switching cam and the distal end of the locking window 20 a smaller Distance is, which is 0.5 to 1 mm in this example. As will be explained below, this distance is used to generate a haptic or acoustic signal intended to signal complete product release. The small distance z arises from the difference between the distance which prevails between the stop face of the control cam 17 pointing in the proximal direction and the stop face pointing in the proximal direction, and the distance between the proximal boundaries of the recess 18 and the stop window 20.

In Figures 6a and 6b, the injection device is shown in a state after a successful product distribution. During the product dispensing, the outer peripheral surface of the sleeve-shaped part of the piston rod 5 presses the blocking element 16 into the recess. tion 18, whereby the blocking element 16 is secured against disengagement from the recess 18 during a product distribution. The piston rod 5 may have a recess or be dimensioned in length so that after the product has been discharged, the securing of the blocking element 16 through the outer Umfangsfiäche the piston rod 5 is omitted, so that the locking element 16, as shown in Figure 6b, from the recess 18 can disengage. The disengagement can be due to an elastically biased arrangement of the locking element 16 or due to the geometry of the locking element 16, which causes a pushing out of the locking element 16 from the recess 18, caused.

At the end of the product distribution, the propulsion spring 6 has further relaxed, while the tension of the tensioned return spring 7 has remained constant. The spring force of the propulsion spring 6 is now lower than the spring force of the prestressed return spring 7. By releasing the engagement of the blocking element 16 with the recess 18, the return spring 7 and the propulsion spring 6 are coupled together again. This coupling causes, as shown in Figures 7a and 7b, the small distance z (see Figures 5b and 6b) disappears by the propulsion structure 2, 10, 11, d. H. In particular, the switching cam 17 is abruptly moved with its proximal end to the distal end of the locking window 20. When the switching cam 17 hits a haptic and / or an acoustic signal is generated. However, by this movement about the small path z, the needle 4 is not yet completely pulled out of the patient. The patient or the user of the device can now wait any time until the needle is completely pulled out of the patient, since he can start the automatic needle retraction of the device by his will.

A complete movement of the needle in the distal end of the housing 1 is not yet possible because, as can be seen from Figure 7b, the switching cam 17 is in engagement with the locking window 20 and thereby blocks the relaxation of the spring 7. To release the retraction of the needle 4, the user of the device only needs to remove it from the injection site. As a result, the return spring 21 can move the actuating sleeve 9 in the distal direction via the switching sleeve 8. In this case, the propulsion structure 2, 10, 11 is fixed relative to the actuating sleeve 9, so that the switching cam 17 augrund its distal configuration driven by the spring 21 in conjunction with the actuating sleeve 9 by means of the projection Id from the locking window 20 is pressed radially inwardly. Once the switching cam 17 inside has been pressed, the needle 4 is free to retreat. In addition, by releasing the engagement, the return spring 7 is released for a return movement. Due to the higher spring force of the prestressed return spring 7, the entire propulsion structure 2, 10, 11 is pressed in the proximal direction. In this case, the spring 6 is tensioned again, the spring force of the return spring 7 being greater than the spring force of the advancing spring 6 during the entire retraction process, ie also until the end of the retraction process.

In FIGS. 9a and 9b, the injection device is shown in a final state. In this state, the injection device again has the same dimensions as in the beginning. Thus, the cap 32 can be replaced and placed the Inj ektions device. In the final position, the needle is fully retracted into the distal end of the device. The snap element 15 is again locked to the shift sleeve 8 as at the beginning. However, a renewed release of the injection device is not possible, since this is a preloaded propulsion spring 6, as z. As shown in Figure Ia, would be necessary.

In FIGS. 10 and 11, the signaling unit of FIGS. 1 to 9 is shown in detail. The grid bar 23 has a grid 30, which comprises a plurality of latching elements 31, which are arranged along the longitudinal direction with gradually decreasing intervals. These distances are reduced by the decreasing spring force. The grid bar is connected at its proximal end, in particular with its head, to the shift sleeve 8 (eg, FIG. The grid rod 23 is surrounded by a grid sleeve 22 which is connected to the distal end of the propulsion spring 6 and / or to the distal end portion of the piston rod 5. The engagement sleeve has an engagement element 26 which engages in an annular groove 27. In particular, the engagement element 26 engages in the starting position in the groove 27 a. During the feed movement for piercing, ie during the piercing movement engages the engagement member from the groove 27 and moves over a first portion of the grid bar to the beginning of the plurality of locking elements 31. The first section has no further locking element but is substantially cylindrical or Tapered so that no signals are emitted during the piercing movement. In principle, embodiments in which this is possible are advantageous. The length of the first portion is dimensioned such that the engagement member 26 has substantially completely traversed the first portion upon completion of the puncturing movement. At the start of the dispensing movement rod 23 and sleeve 22 are pulled further apart, so that the engagement member 26 on the second Ab- cut, ie, the portion with the locking element 31, moves, so that the locking elements 31 are each overrun. Each time the locking elements are passed over, a short click signal is emitted. The time intervals from one click signal to the next are constant, although the decreasing spring force reduces the speed of the engagement member 26 with increasing distance. Erfϊndungsgemäß reduce the distances from one locking element to the next with increasing travel. This takes into account the changing speed.

On the radially opposite side, on which the engagement member 26 is arranged, for example, a further engagement member 26 may be provided. Preferably, as shown here, no further engagement member 26 is provided, but only a support formed by the sleeve wall, which serves as an abutment.

In FIGS. 12 to 14, an alternative embodiment of the signaling unit for the injection device from FIGS. 1 to 9 is shown. The grid 30 is arranged in a groove 29, namely on its flank. The locking elements 31 are in the circumferential direction of the groove edge. In the groove 29, an axially movable carriage 28 is arranged, which is axially fixedly coupled to the piston rod 5. During the dispensing movement, the carriage 28 is entrained by the piston rod 5, as a result of which the engaging element 26 arranged resiliently on the carriage 28 traverses the individual latching elements 31 of the grid 30. Again, the locking elements 31 each have distances from each other, which take into account the changing force of the propulsion spring for a time-constant delivery of signals. The distance of the saw teeth is thus chosen so that the individual clicks are made at regular intervals, although the carriage 28 with the piston rod 5 at the end of the distribution has a lower discharge rate than at the beginning.

FIGS. 15 and 16 show a further embodiment of the signaling unit, in which the grid 30 is formed by recesses, in particular windows, which are likewise mounted on the piston rod 5 with changing distances. The engagement member 26 is resiliently arranged on the functional sleeve 11. When distributing the piston rod 5 and thus the hole pattern 30 is moved past the engagement member 26, which engages in each hole pattern 31 and thus generates the signal. The advantage of this embodiment is that the engaging member 26 can be formed by the blocking element 16, so that this embodiment manages with very few parts.

LIST OF REFERENCE NUMBERS

1 housing

Ia proximal housing part

Ib distal housing part

Ic locking connection

Id pronunciation

2 product container

3 pistons

4 injection needle

5 piston rod

6 propulsion spring

7 return spring

8 shift sleeve

8a socket

9 actuating sleeve

10 product container holder

11 functional sleeve

I Ia covenant

12 viewing window

13 activation element

13a activation cams

14 Activation fuse

15 snap element

16 blocking element

17 switching cams

18 recess

19 Axial stop 0 Locking window 1 Return spring 2 Engagement sleeve 23 grid bar

24 head

25 sliding guide

26 engaging member 27 groove

28 sleds

29 groove

30 grid

31 locking element 32 cap

Z distance

Xo distance xo-Δx changed distance L longitudinal axis

Claims

claims 1. Injection device, in particular autoinjector, comprising: a) a housing (1), b) an actuating sleeve (9) which is mounted movably relative to the housing (1) and can be placed with the distal end of the injection device on an injection site of a patient, c) an injection needle (4) which protrudes beyond the distal end of the injection device in a puncture position and is movable back into the injection device, d) a switching cam (17) which is arranged axially fixed to the injection needle (4) and in the puncture position engages in a locking window (20) to prevent a retraction movement of the injection needle (4) in the interior of the injection device, e) wherein the switching cam (17) by means of the actuating sleeve (9) out of engagement with the locking window (20 ) is movable, so that the injection needle (4) is released for the withdrawal movement. 2. Injection device according to the preceding claim, wherein the housing (1, Id) or a housing-fixed element, the locking window (20) distally and the actuating sleeve (9) define the locking window (20) proximally. 3. Iηjektionsvorrichtung according to any one of the preceding claims, wherein the pointing in the longitudinal direction (L) of the injection device width of the locking window (20) is variable, so that depending on the width of the locking window (20) of the switching cam (17) in or out of Engagement with the locking window (20) is movable. 4. Injection device according to one of the preceding claims, wherein the switching cam (17) has a pointing in the proximal direction stop surface, which can cooperate with the actuating sleeve (9) so that the switching cam (17) of the actuating sleeve (9) during a movement of the Actuating sleeve can be taken in the distal direction when the switching cam (17) in the locking window (20). 5. Injection device according to one of the preceding claims, wherein the switching cam (17) in the distal direction is shaped so that it is movable from the housing (19 or the housing-fixed element out of engagement with the locking window (17)) and / or that of the actuating sleeve (9) is movable out of engagement with a recess formed by the actuating sleeve (9). 6. Inj ektions device according to one of the preceding claims, further comprising an elasticity means (21), in particular spring, which is tensioned by a movement of the actuating sleeve (9) in the proximal direction and with which the actuating sleeve (9) for movement in the distal direction is drivable. 7. Injection device according to one of the preceding claims, wherein the switching cam (17) withdrawn at a in the interior of the Iηjektionsvorrichtung Position, in particular in a starting position and / or an end position of the injection needle (4), in engagement with a of the actuating sleeve (9) proximally of the locking window (20) formed recess (18). 8. Injection device according to one of the preceding claims, wherein the housing (1) or a housing-fixed element has a radially inwardly facing Abragung (Id) which engages in a breakthrough formed by the actuating sleeve (9) so far that the radially inwardly facing inner surface of the Abragung (Id) is approximately flush with the radially inwardly facing inner surface of the actuating sleeve (9). 9. Injection device according to one of the preceding claims, wherein the switching cam (17) is resiliently formed on a part of a propulsion structure, in particular on a Hal sion (10) for a product container (2). 10. Injection device according to one of the preceding claims, wherein the switching cam (17) with a return spring (7) is coupled to the switching cam (17) and thus axially fixedly connected injection needle (4) are movable in the proximal direction. 11. Injection device according to one of the preceding claims, further comprising a blocking element (16) which is fixedly connected to the switching cam (17) via a propulsion structure (2, 10, 11) and which in the puncture position of the injection needle (4) in a Engagement with a proximal of the locking window (20) of the actuating sleeve (9) formed recess (18) is movable. 12. Injection device according to the preceding claim, wherein in the piercing position of the needle (4) of the switching cam (17) in engagement with the locking window (20) and the blocking element (16) is in engagement with the recess (18). 13. An injection device according to claim 12, wherein between the proximal boundary of the locking window (20) and the proximal direction facing stop surface of the switching cam (17) is a small distance (7), in particular from 0.3 to 3mm, wherein the blocking element (16) with its stop surface pointing in the proximal direction in contact with the proximal boundary of the recess (18) of the Actuating sleeve (9) is. 14. Injection device according to the preceding claim, wherein the propulsion structure (2, 10, 11) of the return spring (7) is movable by the amount corresponding to the small distance (Z), whereby a haptic, in particular tactile, or acoustic signal generated becomes. 15. Method for drawing in an injection needle (4) extended from the distal end of an injection device into the interior of the injection device, wherein an actuating sleeve (9) moves out of the distal end of the injection device and thereby engages in a locking window (20) switching cam (17) is moved along by the actuating sleeve (9), wherein in the entrainment movement of the switching cam (17) from the locking window (20) moves and with the injection needle (4) axially fixed switching cam (17) is moved in the proximal direction, so that the extended injection needle (4) is drawn into the interior of the injection device.