Positioning device for a motor vehicle door

Abstract

The invention relates to a positioning device for a motor vehicle door (1). This is equipped in its basic construction with a tappet (3), furthermore with an electromotive drive (4, 5, 6, 7, 8), and with a pyro-actuator (9). The drive (4, 5, 6, 7, 8) and the pyro-actuator (9, 10) act selectively on the tappet (3). According to the invention, the tappet (3) has a teeth (11) for engaging the electromotive drive (4, 5, 6, 7, 8) on one side and at least one stop (13, 14, 15) for the pyro-actuator (9, 10) on the other side.

Description

[0001] Opening device for a motor vehicle door

[0002] Description

[0003] The invention relates to a positioning device for a motor vehicle door, with a tappet, further with an electric motor drive, and with a pyroactuator, wherein the drive and the pyroactuator work selectively on the tappet.

[0004] Motor vehicle door opening devices are increasingly being used in modern automobiles, typically to ensure at least partial opening of handleless vehicle doors. In this case, the door or vehicle door occupies a gap relative to the vehicle body, allowing an operator to fully swing open the vehicle door through the gap created in this way. For this purpose, the vehicle door in question is usually equipped with an additional so-called e-lock, i.e., a vehicle door lock that can be opened by an electric motor.

[0005] Access to the motor vehicle door in question is achieved, for example, by the aforementioned operator starting the opening process with a remote control and / or an (automatically starting) communication (upon approach) between a chip card of the operator and the motor vehicle, after an authorization check, ensures that the electronic lock in question is opened.

[0006] As a result of this lock opening, the vehicle door in question is slightly opened by the spring forces generally generated by a circumferential rubber door seal, but cannot be swung open by the operator if a corresponding exterior door handle is missing. Nowadays, attempts are being made to dispense with such exterior door handles for aerodynamic reasons. As a result, handleless vehicle doors are preferred. Accordingly, following the lock opening, the opening device with its plunger ensures that the vehicle door is swung open relative to the body to such an extent, or to such a gap, that the operator can then reach behind the vehicle door through the gap and swing it open.For this purpose, the positioning device is typically arranged together with the motor vehicle lock inside the motor vehicle door and the extending plunger ensures that the motor vehicle door is pushed off the motor vehicle body.

[0007] This has proven to be fundamentally successful, as exemplified by DE 10 2007 021 840 B4. In this context, it should be emphasized that the term "motor vehicle door" is to be interpreted broadly in this context. This includes not only pivoting side doors, but also, in principle, tailgates, hoods, sliding doors, and even fuel tank flaps, charging port flaps, etc.

[0008] Since the known positioning devices are equipped with an electric motor drive to actuate the plunger, problems can arise if the electric motor drive fails. Such a failure occurs when a motor vehicle battery no longer provides or can no longer provide the required electrical energy to power the electric motor drive. This can occur as a result of a deep discharge of the motor vehicle battery or, in particular, if the electrical supply lines to the electric motor drive are interrupted after a crash. For this reason, the generic prior art according to DE 10 2020 131 792 B3 operates in such a way that the additional pyroactuator is provided.

[0009] With the help of this pyroactuator, a second gear can be axially adjusted if necessary, thereby breaking the operative connection to a first gear. This effectively causes a plunger connected to the second gear to undergo a sudden axial adjustment, thus opening the vehicle door in the emergency situation described. This means that the plunger in question can be actuated either by the electric motor drive in normal operation or by the pyroactuator in emergency operation.

[0010] For this purpose, the known setting device is equipped not only with the electric motor drive, but also with a first shaft carrying the first gear and a second shaft running parallel to the first shaft, on which the said second gear is arranged in a rotationally fixed manner. In addition, a spindle sleeve or tappet is provided that is operatively connected to the second shaft designed as a spindle. This leads to a relatively expansive and complex structure with the two gears and shafts. Furthermore, emergency operation is linked to the axial adjustment of the second gear, thereby breaking the operative connection to the first gear. This means that, in addition to the relatively expansive and complex structure, malfunctions can also occur, namely when the two gears are clamped against each other during emergency operation, or cannot be easily separated from each other. The invention aims to remedy this situation.

[0011] The invention is based on the technical problem of further developing such a positioning device for a motor vehicle door in such a way that a functional and compact design is ensured.

[0012] To solve this technical problem, the invention proposes, in a generic opening device for a motor vehicle door, that the tappet has, on the one hand, a toothing for engagement of the electric motor drive and, on the other hand, a stop for the pyroactuator.

[0013] In this way, a compact yet functional design is achieved. This is because the plunger assumes a central function in that its adjustment is carried out directly with the help of the electric motor drive during normal operation. Namely, the plunger is equipped with teeth for engagement of the electric motor drive and is adjusted axially. On the other hand and independently of this, emergency operation is also directly possible. In this case, the pyroactuator alternatively ensures the required axial adjustment of the plunger via the stop. In fact, the axial adjustment of the plunger is brought about either by the electric motor drive during normal operation or by the pyroactuator during emergency operation. In principle, parallel loading of the plunger with the electric motor drive and additionally with the pyroactuator is also possible.

[0014] To realize and implement this in detail, the gearing generally runs along the length of the tappet. Furthermore, the drive engages the gearing via a gear. In addition to the gear, the drive typically also has at least one electric motor.

[0015] Furthermore, and advantageously, the drive is usually equipped with a drive pulley and a spring in addition to the gear and electric motor. The design is such that the electric motor, with its output shaft (possibly with the interposition of a gear), meshes with the drive pulley and sets it in rotation. The drive pulley, in turn, works with the interposition of a spring on the gear, which in turn engages the teeth along the longitudinal extension of the tappet.

[0016] The design is furthermore such that the radius of the gear varies along the travel path of the plunger and generally increases. This means that at the beginning of the plunger's travel path, the gear meshing with the teeth in the longitudinal extension of the plunger operates with a small radius on the plunger to drive it, which radius increases over the plunger's travel path. As a result, at the beginning of the plunger's travel path, a low torque is generally available for its axial adjustment, which torque increases over the plunger's travel path. This applies at least under the assumption that the electric motor rotates the gear with the same force and that, due to the radius increasing over the travel path, the torque increases along the plunger's travel path - as described.

[0017] Of course, other designs are also conceivable and are encompassed by the invention. Since the gearwheel is optionally coupled to the electric motor or the drive pulley as further components of the electric motor drive with the interposition of the spring, a particularly functional loading of the tappet with the help of the electric motor drive and also the pyroactuator is provided. This is because in normal operation there is the possibility that the spring interposed between the gearwheel and the drive pulley or the electric motor is tensioned in the event of any blockages of the tappet. This is the case, for example, if the motor vehicle door that can be loaded using the tappet is frozen shut. In this case, after a certain rotation path of the drive pulley orof the electric motor means that, for example, via a stop on the drive pulley with a simultaneously tensioned spring, the drive pulley strikes the gear wheel and in this way provides an "icebreaker function" and opens the vehicle door, breaking through any layer of ice.

[0018] Typically, however, the interposed spring ensures that the rotational movement of the drive pulley or electric motor is transferred to the gear. This approach has the further advantage that, in emergency operation and when the electric motor drive is stationary, the pyroactuator can easily apply pressure to the plunger beyond the stop, ensuring the desired axial adjustment of the plunger. In this case and during emergency operation, the spring allows a relative movement between the gear, which moves together with the plunger, and the drive pulley or electric motor, which is stationary relative to it. For this purpose, the spring is advantageously designed as a spiral spring, which can be inserted into a cavity in the drive pulley.

[0019] This means that, on the one hand, the spring provides overload protection during normal operation, for example when the plunger is blocked during operation (if the vehicle door is blocked by ice or something else). On the other hand, the spring ensures that the electric motor drive does not have to be "dragged along" during emergency operation. This is because in emergency operation, the gear wheel is moved together with the plunger by the pyroactuator, and the intermediate spring ensures that this movement is possible under tension of the spring, even when the drive pulley is stationary or the electric motor is not actuated. This means that only minimal operating forces are required during emergency operation, and consequently, even a compact and cost-effective pyroactuator can be used.

[0020] In this context, it is understood that one or more sensors are also provided. For example, a microswitch can be installed that registers the axial movement of the plunger. This microswitch monitors and senses, among other things, the retracted and extended states of the plunger and transmits this information to a control unit. Furthermore, a further sensor in the form of a proximity sensor is implemented, which detects the distance between the plunger and the vehicle door. This ensures that the positioning device is actually only activated when the vehicle door is closed.

[0021] The specific design of the stop on the plunger for the pyroactuator can be implemented in various ways. For example, it is conceivable that the stop is located at the end and / or approximately in the center of the plunger. Alternatively or additionally, it is also possible for the stop to be located inside the at least partially hollow plunger. In this case, the plunger is usually constructed in two parts: a cylinder that accommodates the pyroactuator and a piston that contains the stop.

[0022] This means that in this case, the pyroactuator is housed in the cylinder and operates with a plunger that can be extended upon ignition of the pyroactuator and acts on the piston as a further component of the two-part tappet. For this purpose, the piston is equipped with a stop, which is generally located inside the piston and on its front side. As soon as the pyroactuator or the propellant charge inside it is ignited, the extending plunger ensures that the piston, with the internal stop, is moved away from the cylinder. In this case, the cylinder housing the pyroactuator remains stationary, and only the piston is moved, ensuring the desired opening movement of the vehicle door in emergency operation.

[0023] As a result, measures such as the spring as a component of the electric motor drive are unnecessary in this variant, because the gearing is usually provided in the longitudinal extension of the tappet on the cylinder. Since in emergency operation the electric motor, as well as the gear and the cylinder, remain stationary, whereas only the piston is moved axially with the help of the pyroactuator, an overall simple and cost-effective variant can be realized in this case. This simplifies assembly and reduces costs, simply due to the small number of required components. In fact, in this case, not only the spring but also the drive disk are usually dispensable, so that the electric motor can work directly on the gear, if necessary with the interposition of the gearbox.

[0024] In a further embodiment, it has proven effective if the pyroactuator acts entirely on the plunger via an intermediary lever. This lever can provide a deflection or an increase in torque in conjunction with the actuation of the plunger. For the reasons described above, the triggering of the pyroactuator is generally associated with the plunger extending due to the ignited propellant charge and, in the variant mentioned, acting on the lever, for example pivoting it around its axis. This allows the plunger to act on one end of the lever, which can be designed as a two-arm lever, for example, while the other end of the two-arm lever moves against the stop on the plunger, thereby adjusting it axially. Finally, it has proven particularly effective and advantageous if the pyroactuator and the plunger overlap at least partially in their respective longitudinal extents and in plan view.In the case where the pyroactuator engages the cylinder in the two-part embodiment of the plunger with the cylinder and piston, even a complete overlap is possible. In any case, the at least partial overlap between the pyroactuator and the plunger in their respective longitudinal extensions ensures that the positioning device according to the invention is particularly compact and small in design. This is further enhanced by the fact that the gearwheel engaging the teeth on the plunger, and thus also the electric motor drive, also overlaps with the plunger, thus providing an overall nested design with compact dimensions.

[0025] The previously described positioning device can, in principle, be arranged and mounted inside a motor vehicle door or tailgate. However, it is equally conceivable to place the positioning device in question inside a motor vehicle body. In this case, mounting it in a B-pillar of a motor vehicle body has proven advantageous, for example, if the positioning device is to be used to raise a motor vehicle side door.

[0026] All this is achieved by considering a functional and cost-effective design that ensures and provides flawless normal operation as well as emergency operation. These are the key advantages.

[0027] The invention is explained in more detail below using a variant which merely represents an exemplary embodiment; in the following:

[0028] Fig. 1 shows the installation device according to the invention in a first embodiment, Fig. 2 shows another further second variant,

[0029] Fig. 3 shows a third embodiment of the installation device according to the invention and

[0030] Fig. 4 the drive in detail.

[0031] The figures show a positioning device for a merely indicated motor vehicle door 1. The motor vehicle door 1 is not limited to a motor vehicle side door. The motor vehicle door 1 or motor vehicle side door is pivotally hinged relative to an indicated motor vehicle body 2. With the aid of the positioning device, the motor vehicle door 1 is moved from its solid-line position into a dashed-line raised position. This creates a gap or engagement gap S of the associated and schematically illustrated door leaf relative to the motor vehicle body 2, through which an operator can grasp the door leaf and pivot it fully open. This generally requires that the motor vehicle door 1 has first been opened.

[0032] For this purpose, a motor vehicle lock equipped with an electric motor opening drive (not shown) may also be provided. The motor vehicle lock (not shown) and the positioning device, which will be described in detail below, are indicated for this purpose and according to the exemplary embodiment inside the motor vehicle door 1. There is also the possibility that the motor vehicle lock and the positioning device in question define a structural unit. In any case, the positioning device, which will be described in detail below, can extend a plunger 3 in the axial direction A. During its adjustment in the axial direction A, the plunger 3 moves against the indicated motor vehicle body 2, for example a B-pillar of the motor vehicle body 2 if the motor vehicle door 1 is a front motor vehicle side door.As a result, the motor vehicle door 1 is opened, namely from the solid position to the dashed position, forming the gap or engagement gap S.

[0033] To actuate and move the plunger 3 in the axial direction A, an electric motor drive 4, 5, 6, 7, 8 is implemented, which is shown separately in Figure 4. Furthermore, a pyroactuator 9, 10 is provided independently to actuate the plunger 3 in the axial direction A. The electric motor drive 4, 5, 6, 7, 8 and the pyroactuator 9, 10 operate selectively on the plunger 3. In fact, the design is such that the plunger 3 is moved in the axial direction A during normal operation using the electric motor drive 4, 5, 6, 7, 8. However, if the electric motor drive 4, 5, 6, 7, 8 fails, the pyroactuator 9, 10 ensures, alternatively and optionally, in emergency operation, that the plunger 3 is extended and moved in the axial direction A.

[0034] Based on the separate detailed illustration of the electric motor drive 4, 5, 6, 7, 8 in Figure 4, it can be seen that it is initially equipped with an electric motor 4. The electric motor 4 meshes with an optional gearbox 5. With the help of the gearbox 5 or the electric motor 4, a drive disk 6 is set in rotation. The drive disk 6 works with the interposition of a spring 7 on a gear 8. The design is such that the spring 7 is designed as a spiral spring and fits into a cup-shaped recess in the drive disk 6. Furthermore, the drive disk 6 and the gear 8 are mounted coaxially.

[0035] The rotations of the electric motor 4 are now transmitted to the drive pulley 6 via the gear 5, which may be equipped with external gearing for this purpose. Since the spring or spiral spring 7 is connected to the drive pulley 6, the spring 7 moves together with the drive pulley 6.

[0036] The gear 8 is connected to the spring or spiral spring 7 by a pin at its end, so that rotational movements of the drive disk 6 are transmitted to the gear 8 via the interposition of the spring 7. According to the exemplary embodiment, the gear 8, or its rotations around the axis shared with the drive disk 6, result in the plunger 3 being moved "to the left" in the axial direction A when the gear 8 moves clockwise. For this purpose, the plunger 3 has, according to the exemplary embodiment, a toothing 11 which, according to the exemplary embodiment, runs in the longitudinal extension of the plunger 3.

[0037] This means that a clockwise movement of the drive disk 6 and consequently also of the gear 8 with the interposition of the spring 7 results in the plunger 3 being moved in the axial direction A by the engagement of the gear 8 with the toothing 11 on the plunger 3, and according to the exemplary embodiment extends to the "left" relative to a housing 12 accommodating the setting device. It can be seen that for this purpose the gear 8 has a different radius R. The design according to the exemplary embodiment is such that the radius R increases over the adjustment path or travel path of the plunger 3, which leads to the engagement gap S. Correspondingly, the toothing 11 is correspondingly inclined in the longitudinal extent of the plunger 3 so that the gear 8 can continue to engage with the toothing 11 with its external toothing, taking into account the increasing radius R.As a result, according to the exemplary embodiment and not by way of limitation, the electric motor drive 4, 5, 6, 7, 8 operates with increasing torque along the travel path of the plunger 3, as already described in the introduction. This, of course, applies only as an example.

[0038] Of particular importance for the invention is the fact that the plunger 3 not only has the aforementioned toothing 11 in its longitudinal extension, specifically for engagement with the electric motor drive 4, 5, 6, 7, 8 and specifically with the gear 8 as a component of the electric motor drive 4, 5, 6, 7, 8, but additionally and on the other hand, a stop 13, 14, 15 is provided for the pyroactuator 9, 10. The stop 13, 14, 15 in question can be provided at the end and / or approximately in the center of the plunger 3. Fig. 1 shows that both a central stop 14 and an end stop 13 are each integrally formed on the plunger 3. In fact, the plunger 3 is, for example, a plastic injection-molded part or a metal injection-molded part. The gear 8 may also be designed as a plastic injection-molded part.The same applies to the drive pulley 6 and the gear 5 as further components of the electric motor drive 4, 5, 6, 7, 8.

[0039] In the variant according to Fig. 2, only the end stop 13 is implemented. The variant according to Fig. 3 differs from the exemplary embodiments of Figs. 1 and 2 additionally in that in this case the stop 15 there is provided inside the at least partially hollow plunger 3. In fact, the variant according to Fig. 3 is designed such that in this case the plunger 3 is formed in two parts, with a cylinder 3a accommodating the pyroactuator 9, 10 and a piston 3b having the stop 15 as both components 3a, 3b of the plunger 3.

[0040] The pyroactuator 9, 10, in turn, consists of a sleeve 9 containing an ignitable chemical propellant charge and a plunger 10. As soon as the chemical propellant charge inside the sleeve 9 is ignited, its expansion ensures that the plunger 10 is extended, as can be seen in Figure 3. In the variant according to Figure 3, the extended plunger 10 now moves against the stop 15 provided inside the piston 3b, which in the exemplary embodiment is located on the front side of the piston 3b. This causes the piston 3b to extend relative to the stationary cylinder 3a (to the "left"). This means that in the variant according to Figure 3, neither the spring 7 nor the drive disk 6 need to be implemented as components of the electric motor drive 4, 5, 6, 7, 8. This will be explained in more detail below.

[0041] Finally, as can be seen in Fig. 2, the pyroactuator 9, 10 additionally operates on the plunger 3 via the interposition of a lever 16a, 16b. According to the exemplary embodiment, the lever 16a, 16b is a two-arm lever pivotally mounted in the housing 12 about its central axis. This allows, in emergency operation and when the plunger 10 of the pyroactuator 9, 10 is extending, the extending movement of the plunger 10 can be redirected in the opposite direction. In this way, the pyroactuator 9, 10 and the plunger 3 can be arranged relative to one another in their respective longitudinal extensions and in plan view, and positioned inside the housing 12 such that they at least partially overlap.Furthermore, since the electric motor drive 4, 5, 6, 7, 8 engages with its gear 8 into the toothing 11 of the tappet 3, there is also an overlap at this point, resulting in a nested structure which leads to compact dimensions and the small-sized housing 12.

[0042] The functionality is as follows. During normal operation, a control unit (not shown) first ensures that, starting from the closed position of the motor vehicle door 1, the motor vehicle lock or motor vehicle door lock (not shown) is opened. This is usually done by an electric motor. As a result, the motor vehicle door 1 in question is already slightly raised relative to the motor vehicle body 2 by means of counterforces built up by a previously compressed circumferential seal. The control unit in question then actuates the setting device, specifically the electric motor drive 4, 5, 6, 7, 8.

[0043] In the exemplary embodiment, the electric motor drive 4, 5, 6, 7, 8 ensures that the gear 8 provided on the output side of the electric motor drive 4, 5, 6, 7, 8 engages with its outer peripheral toothing into the toothing 11 in the longitudinal extension of the tappet 3. As a result, the tappet 3 is moved "to the left" in the axial direction A in the exemplary embodiment. This leads to the tappet 3 moving against the motor vehicle body 2 or a B-pillar there. Since the positioning device as well as the motor vehicle lock (not shown) are arranged inside the motor vehicle door 1, this leads to the motor vehicle door 1 or the door leaf indicated in the figures moving from its solid position to the dashed position, taking into account the engagement gap S. Now the door leaf and thus the vehicle door can be picked up and swung open completely by an operator during normal operation.

[0044] However, if an emergency occurs and the electric motor drive 4, 5, 6, 7, 8 fails, for example, as a result of a crash, the electric motor drive 4, 5, 6, 7, 8 can no longer be actuated. The control unit already mentioned then ensures that the chemical propellant charge inside the pyroactuator 9, 10 is ignited. This causes the plunger 10 of the pyroactuator 9 to extend from the sleeve 9 that houses it. Possibly with the interposition of the lever 16a, 16b, the pyroactuator 9, 10 operates against the stop 13, 14, 15 on the plunger 3.

[0045] The crash or crash event is initiated by the control unit (not expressly shown) when the signal from an associated crash sensor indicates such a crash. The crash sensor can be an acceleration sensor installed in the motor vehicle body. In addition, the pyroactuator 9, 10 is only actuated by the control unit when the motor vehicle lock (not shown) inside the motor vehicle door 1 has also been opened beforehand. In this case, too, this door opening can be detected by a signal from a sensor on the part of the control unit, for example. The sensor can be one that is assigned to the locking mechanism inside the motor vehicle lock and detects a locking mechanism opening. I.e., the control unit ensures the ignition of the chemical propellant charge inside the pyroactuator 9, 10 only when the crash signal is present and the motor vehicle door 1 or the associated motor vehicle lock is opened.

[0046] In the embodiments according to Figs. 1 and 2, this results in the plunger 3 being moved "to the left" again and the motor vehicle door 1 being opened, taking into account the resulting engagement gap S. As a result, the motor vehicle door 1 can be swung open by the operator in emergency operation in the same way as in normal operation.

[0047] Since the electric motor 4, the downstream gear 5, and also the drive pulley 6 remain stationary during this process, the spring 7 located between the drive pulley 6 and the gear 8 ensures that the described movement of the plunger 3 is permitted by means of the pyroactuator 9, 10. During this process, the spring 7 is tensioned or deflected, respectively, and consequently permits the movement of the plunger 3 in the axial direction A as well as the associated pivoting movement of the gear 8.

[0048] In the embodiment according to Fig. 3, however, the drive disk 6 and the spring 7 are fundamentally dispensable, so that the electric motor 4 can actuate the gear 8 directly, if necessary with the interposition of the gear 5. This can be attributed to the fact that in the embodiment according to Fig. 3, in emergency operation, the cylinder 3a with the pyroactuator 9, 10 accommodated therein or its sleeve 9 remains at rest, whereas only the plunger 10 extends together with the piston 3b. This leads to a cost-optimized solution with reduced components, as already described in the introduction. Finally, it should be emphasized that the control unit, not shown in the embodiment and arranged, for example, inside the housing 12, is additionally equipped with its own electrical power supply, an energy storage unit, or its own power supply.This ensures that the pyroactuator 9, 10 can be safely actuated in the event of a crash and ensures the opening movement of the motor vehicle door 1. As already explained, the housing 12 in question can be arranged both inside the motor vehicle door 1 and inside the motor vehicle body 2. In principle, a mixed arrangement in both the motor vehicle door 1 and the motor vehicle body 2 is also possible, but not preferred. Reference symbol list.

[0049] Motor vehicle door 1

[0050] Motor vehicle body 2

[0051] Tappet 3

[0052] Cylinder 3a

[0053] Piston 3b

[0054] Electric motor 4

[0055] Gearbox 5

[0056] Drive pulley 6

[0057] Spring 7

[0058] Gear 8

[0059] Sleeve 9

[0060] Drive 4, 5, 6, 7, 8

[0061] Pyroactuator 9, 10

[0062] Stamp 10

[0063] Gearing 11

[0064] Housing 12

[0065] Attack 13, 14, 15

[0066] Lever 16a, 16b

[0067] Axial direction A

[0068] Engagement gap S

[0069] Radius R

Claims

Patent claims 1. A device for opening a motor vehicle door (1), comprising a tappet (3), further comprising an electric motor drive (4, 5, 6, 7, 8), and a pyroactuator (9, 10), the drive (4, 5, 6, 7, 8) and the pyroactuator (9, 10) selectively operating on the tappet (3), characterized in that the tappet (3) has, on the one hand, a toothing (11) for engagement of the electric motor drive (4, 5, 6, 7, 8) and, on the other hand, at least one stop (13, 14, 15) for the pyroactuator (9, 10).

2. Device according to claim 1, characterized in that the toothing (11) runs in the longitudinal extension of the plunger (3).

3. Device according to claim 1 or 2, characterized in that the drive (4, 5, 6, 7, 8) engages with a gear (8) in the toothing (11).

4. Device according to claim 3, characterized in that the gear wheel (8) has a different radius (R) and is optionally coupled with the interposition of a spring (7) to an electric motor (4) as a further component of the electric motor drive (4, 5, 6, 7, 8).

5. Device according to claim 4, characterized in that the radius (R) increases along the travel path of the plunger (3).

6. Device according to one of claims 1 to 5, characterized in that the stop (13, 14, 15) is provided at the end and / or approximately in the center of the plunger (3).

7. Device according to one of claims 1 to 6, characterized in that the stop (13, 14, 15) is provided in the interior of the at least partially hollow plunger (3).

8. Device according to one of claims 1 to 7, characterized in that the plunger (3) is formed in two parts with a cylinder (3a) receiving the pyroactuator (9, 10) and a piston (3b) having the stop (15).

9. Device according to one of claims 1 to 8, characterized in that the pyroactuator (9, 10) operates on the plunger (3) with the interposition of a lever (16a, 16b).

10. Device according to one of claims 1 to 9, characterized in that the pyroactuator (9, 10) and the plunger (3) overlap at least partially (in plan view) in their respective longitudinal extent.

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