WO2018095503A1

WO2018095503A1 - Safety device for a motor vehicle seat

Info

Publication number: WO2018095503A1
Application number: PCT/EP2016/001973
Authority: WO
Inventors: Jun Liu
Original assignee: Audi Ag
Priority date: 2016-11-23
Filing date: 2016-11-23
Publication date: 2018-05-31

Abstract

The invention concerns a safety device (20) for a motor vehicle comprising: - A housing element (22); - A trigger element (24) being configured to be movable between a resting position and a triggering position and being movably mounted to the housing element (22); - A tilting device (26) being configured to move an attached headrest (16) from a starting position to a safety position in response to the trigger element (24) being moved from the resting position to the triggering position, whereby the safety device (20) is designed to be mounted on the motor vehicle in an installation position defined with regard to a longitudinal vehicle direction and that the trigger element (24) is configured to be movable relative to the housing element (22) from the resting position to the triggering position by an inertia force acting on the trigger element (24) in the longitudinal vehicle direction.

Description

SAFETY DEVICE FOR A MOTOR VEHICLE SEAT

DESCRIPTION: The invention relates to a safety device for a motor vehicle according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle.

US 2005/0035642 A1 describes a headrest that automatically tilts forward in the case of a crash so that a passenger is protected from possible whiplash injuries. The headrest comprises a tilting mechanism that is spring loaded. The tilting mechanism is activated by an electromagnet, which obtains a pulse from a sensor. The sensor can for example be an acceleration sensor, which is used as a means for detecting a rear end impact. It can be disad- vantageous to trigger the tilting mechanism with a pulse from such a sensor, as this can result in a too long reaction time to protect the passenger especially well from a whiplash injury.

DE 103 02 778 A1 describes a headrest with a mechanism that allows lateral sections of the headrest to be automatically tilted sideways closer to a head of a passenger in the case of a sideway impact on the car. The tilting of the lateral sections of the headrest is triggered by an inertia force acting on an unlocking mechanism in a transverse vehicle direction. However, such a headrest can not protect passenger from whiplash injuries due to a rear end impact.

DE 10 2004 023 395 B3 discloses a headrest with a tilting mechanism that can tilt the headrest forward in the case of a rear end impact on the car. The tilting of the headrest is triggered by an actuator. The headrest also compris- es a locking mechanism that locks the headrest in a forward tilted position. The triggering of the tilting of the headrest by an actuator may be too slow to protect a passenger especially well and may have reliability issues in the case of a crash. It is an object of the present invention to provide a safety device for a motor vehicle indicated in the preamble of patent claim 1 , by means of which the safety of a motor vehicle can be increased with particular reliability. Furthermore, it is an object of the present invention to provide a motor vehicle with particular safety.

This object is solved by a safety device having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

A first aspect of the invention concerns a safety device for motor vehicle. This safety device comprises a housing element. Furthermore, this safety device comprises a trigger element being movably mounted to the housing element and being configured to be movable between a resting position and a triggering position. This means the trigger element moves relatively to the housing element between the resting position and the triggering position. Furthermore, the safety device comprises a tilting device being configured to move an attached headrest from a starting position to a safety position in response to the trigger element being moved from the resting position to the triggering position. The starting position is the regular position of a headrest as configured by, for example, a passenger. The safety position is a position where the headrest is at least partially closer to the head of a passenger seated in front of the headrest than in the starting position. Typically, the headrest is tilted forward by 3-5 degrees relatively to a backrest of a seat when the headrest is moved from its starting position to its safety position in order to prevent a passenger from a whiplash injury in the case of a rear end impact. This moves at least a portion of the headrest approximately 2-10 cm closer to the head of a passenger seated in front of the headrest. A rear end impact, also called rear end collision or rear impact crash, is a special form of car crash. A rear end impact means that a car hits a slower moving car in its front. The car being hit is accelerated forward due to this impact. Due to inertia forces, the head of a passenger in the car being hit is correspondingly accelerated backwards relative to the backrest of its seat due to the rear end impact. This can result in so called whiplash injuries.

For example, the headrest can be attached to the tilting device by the same bars as it is usually attached to the backrest of a corresponding motor vehicle seat without the safety device. The tilting mechanism can tilt the headrest forward by turning those bars forward at their attachment point to the tilting device. Thus, at least a portion of the backrest is closer to a head of the passenger in the safety position than in the starting position. For this discription, forward is defined as the longitudinal vehicle direction in which the motor ve- hide is usually driving forward. It can also be understood as the longitudinal vehicle direction facing forward to the front of the motor vehicle form the seat and/or the headrest and/or the safety device. Due to the headrest being moved in its safety position in the case of a rear end impact, the risk of a whiplash injury is greatly reduced.

To provide a safety device for a motor vehicle that increases the motor vehicle safety with particular reliability, the safety device according to the invention is designed to be mounted on the motor vehicle in an installation position defined with regard to the longitudinal vehicle direction. The trigger element is configured to be movable relative to the housing element from the resting position to the triggering position by an inertia force acting on the trigger element in the longitudinal vehicle direction when the safety device is mounted in the installation position. Thus, the trigger element can be understood as a kind of mechanical, passive sensor which can detect a rear end impact and which can also mechanically simultaneously trigger the movement of the headrest from the starting position to the safety position. No electrical or other sensor components are needed, which could fail in the case of a crash. Thus, the safety device has a particular reliability. Furthermore, an inertia activated trigger element can react much faster than an electrical sensor, especially if the electrical sensor is combined with an electrical actuator as a tilting device. Thus, the safety device can move the headrest particularly fast from the starting position into the safety position by means of the tilting device. The tilting device is preferably also a purely mechanical component without any electrical components. Thus, it can be ensured with particular reliability that the headrest will be moved into the safety position before the head of a passenger snaps back too far during a rear impact. This prevents whiplash injuries. Thus, the safety of the motor vehicle can be especially increased with the safety device. For example, the tilting device comprises at least coil spring that is configured to move the headrest from the starting position to the safety position. A coil spring can provide a sufficient force with an especially small installation space. Furthermore, the tilting device comprising a coil spring can move the headrest much more reliable and much faster than a tilting device comprising some form of actuator. In its installation position, the safety device can for example be attached to the backrest of the seat, the headrest and/or some form of link between the headrest and the backrest by means of its housing element. The safety device with its housing element can also constitute such a link between the headrest and the backrest. This means the safety device with its housing element can also be used as a means to attach the headrest to the backrest when mounted on the motor vehicle.

In an advantageous embodiment of the invention, the tilting device features an installation position defined with regard to the longitudinal vehicle direction and the tilting device is configured to move at least a portion of the attached headrest forward along the longitudinal vehicle direction when the headrest is moved from the starting position to the safety position. Again, forward is defined as the normal forward driving direction corresponding to the longitudinal vehicle direction.

In an advantageous embodiment of the invention, the safety device comprises a control element, by means of which a threshold value for the inertia force acting on the trigger element can be determined, above which the trig- ger element is movable from the resting position to the triggering position. The control element can be used as a mean to set a threshold value for the severity of a rear impact above which the safety device will react by moving the headrest from the starting position to the safety position of the tilting device. For example, the control element can be configured as a simple me- chanical spring. Another advantage of the control element, especially if configured as a spring, is to keep the trigger element in its resting position at all times when an inertia force acting on the trigger element in the longitudinal vehicle direction is below the threshold value. This means the control member can prevent a creeping of the trigger element from the resting position to the triggering position over time. Such a creeping could otherwise occur due to, for example, inertia forces acting on the trigger element due to strong braking manoeuvres. The control element can prevent a false triggering of the tilting device and thus especially increases the reliability of the safety device.

In an advantageous embodiment of the invention, the trigger element is movably mounted to the housing element by means of at least one rolling element. For example, the rolling element can be a barrel element, a ball element or some other form of bearing element. This can greatly reduce the friction between the trigger element and the housing element. This allows for an especially fast and reliable reaction of the safety device in the case of a rear end impact. Furthermore, in order to be able to tilt the headrest forward sufficiently fast during a rear end impact, an especially high movement force must be provided by the tilting device. For example, 20 Nm torque may be required for a sufficiently fast deployment of the headrest into the safety position. Also regulations for headrest static tests may require the headrest to be loaded with a backwards acting force. For example, a force of 890 N is applied on the headrest during tests as per regulation requirements. This may result in the safety device and/or the mounting of the trigger element on the housing element to be subjected to especially high loads. These high loads may result in especially high friction forces between the trigger element and the housing element. Still, it has to be ensured that the trigger element can be moved from the resting position to the triggering position by an inertia force despite these loads and the resulting friction. Without the mounting of the trigger element by means of at least one rolling element to the housing element, the trigger element could possibly be jammed in its resting position due to this friction. Thus, the rolling element especially increases the reliability of the safety device.

In an advantageous embodiment of the invention, the safety device comprises a holding element that is configured to be moved between a retaining position and a release position, by means of which the movement of the headrest from the starting position to the safety position is blocked by the holding element in the retaining position and released by the holding element in the release position, whereby the movement of the holding element from the retaining position to the release position is blocked by the trigger element in the resting position and released by the trigger element in the triggering position. This means the trigger element in the resting position itself does not block the movement of the headrest by means of the tilting device. Instead, the holding element holds the headrest in its starting position. For example, the holding element comprises a pawl element that keeps the headrest in its starting position against the force of a preloaded coil spring of the tilting device. Thus, the trigger element itself is not a subject to a force exerted by the preloaded coil spring. This means, the trigger element can be moved much more freely relatively to the housing element and/or with less force. Accordingly, the safety device can react especially reliable to a rear end impact. Furthermore, the safety device can be designed to be triggered by a rear impact with particular low impact forces. In an advantageous embodiment of the invention, a force is applied to the holding element in the retaining position by means of which the spring element, by means of which the holding element is movable from the retaining position to the release position with the trigger element being in the triggering position. This force can be much smaller than the force applied to the headrest by the tilting mechanism for moving the headrest from the starting position to the safety position. The holding element is spring loaded in its retaining position and is thus automatically moved into the release position when the trigger element is moved into the triggering position without the need for sensors, electrical components and/or actuators. Overall, this allows for a purely mechanical design of the safety device with an inertial activated tilting device, a spring loaded tilting device and a spring loaded holding element. In an advantageous embodiment of the invention, the trigger element comprises a recess corresponding at least to a section of the holding element, in which the holding element is at least partially movable for moving from the retaining position to the release position with the trigger element in the triggering position. This allows the design of a particular small safety device as the combination of trigger element and holding element needs a particular small installation space. Furthermore, the recess corresponding to at least the section of the holding element allows the release of the holding element by the trigger element in the triggering position without any further movable components. The resulting safety device is particular reliable. The recess in the trigger element is also easy and inexpensive to manufacture.

In an advantageous embodiment of the invention, at least a portion of the holding element features a profile, especially a wave profile and/or a saw tooth thread profile, by means of which the movement of the headrest from the starting position to the safety position can be blocked by the holding element in the retaining position. For example, the profile of the holding element can be engaged to a corresponding profile of a movable element of the tilting device in the retaining position of the holding element. The profile can bear a lot of force on a particular small contact surface, resulting in a particular small installation space.

The coil spring can exert enough force on the casing element that it disengages the holding element automatically from the casing element once the trigger element has been moved into the triggering position because of the profile. For example, the holding element is pushed into the recess because a movable casing element is tension loaded by the coil-spring element and the profile transfers the tension moment to a pushing force on the holding element. In this case, it is not necessary to provide a force by means of which the holding element is movable from the retaining position to the release position with the trigger element being in the triggering position by means of the spring element. Without this spring element the safety device is especially economic to manufacture. In order to release the movement of the headrest from the starting position to the safety position the holding element only has to be moved by roughly the length of the depth of the profile. For example, the profile can have a depth of less than 5 mm, preferably less than 3 mm. This means there can be a particular small movement for moving the holding element from the retaining position to the release position. This allows for a particular fast reaction time of the safety device in the case of rear end impact. The reaction time can be defined as the time that passes between the rear impact and the time when the headrest has reached its safety position. In an advantageous embodiment of the invention, the trigger element and the holding element are movably mounted to each other by means of at least one rolling element. This rolling element can be similar to the rolling element by means of which the trigger element is movable mounted to the housing element. The movable mounting of the trigger element and the holding ele- ment to each other by means of a rolling element has similar advantages as the rolling element by means of which the trigger element is movable mounted to the housing element. The movable mount of the trigger element and the holding element to each other by means of the at least one rolling element allows for a safety device with a particular reliability and short reaction time.

In an advantageous embodiment of the invention, the tilting device comprises a locking device, by means of which the headrest can be locked in the safety position, whereby the locking device is detachable for a reset of the headrest from the safety position to the starting position. The locking device ensures that the headrest stays in the safety position regardless of a further vehicle movement and/or forces acting on the headrest. This ensures that a passenger is particularly well protected against whiplash injuries. Due to the locking device being detachable for a reset of the headrest the safety device and/or the headrest can be reused after a rear end impact which has triggered the reaction of the safety device.

A second aspect of the invention concerns a motor vehicle with a passenger seat and with a headrest. According to the invention, this motor vehicle also comprises at least one safety device according to the first aspect of the invention. Preferably, this safety device is used to mount the headrest to the backrest of the at least one passenger seat of the motor vehicle. Preferably there is at least one safety device corresponding to at least each passenger seat with a headrest. Such a motor vehicle is particularly safe for its passengers. Embodiments of the first aspect of the invention are also embodiments of the second aspect of the invention. The reverse is also true.

Further advantages, features and details of the invention are apparent from the following description of a preferred embodiment as well as based on the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respective specified combination, but also in other combinations or alone without departing from the scope of the invention.

The drawings show in:

Fig. 1 a schematic side view of a motor vehicle seat mounted into a testing device;

Fig. 2-4 respectively a schematic front view, side view and back view of a safety device for a motor vehicle; Fig. 5 a schematic sectional view of the safety device as shown in Fig.

4;

Fig. 6-8 an illustration in three schematic sectional views of the safety device according to Fig. 5 on how a trigger element of the safe- ty device triggers a response of the tilting device of the safety device during a rear end impact;

Fig. 9 a schematic sectional view of the safety device with an alternative design; Fig. 10 a schematic sectional view of the safety device with another alternative design; and Fig. 11 an exploded drawing of the safety device according to Fig. 9.

Fig. 1 shows in a schematic perspective view a motor vehicle seat 10 mounted into a testing device 12. The seat 10 comprises a backrest 14 and a headrest 16, which are attached to each other. The testing device 12 applies loads to the seat 10, especially the backrest 14 and the headrest 16, in order to prove that the seat 10 meets regulation requirements. Specifically, the testing device 12 applies a load of 890 N to the headrest. This and the direction of this force are indicated by arrow 18. Usually, the seat 10 is mounted into a motor vehicle in such a position that a passenger seated on the seat 10 is facing forward in the forward driving direction of the motor vehicle. In the case of a rear end impact on the motor vehicle, a passenger seated on the seat 10 is accelerated backwards into the seat 10. If the distance between the headrest 16 and a head of the passen- ger is particular high, this can lead to a so-called whiplash injury. Due to this reason, the headrest 16 should be as close as possible to the head of the passenger. However, a particularly close position of the headrest 16 to the head of the passenger can result in an uncomfortable position for the passenger during normal driving conditions.

To provide a solution to those two conflicting interests, a safety device 20 can be provided. An example of this safety device 20 is shown in the schematic side views of Fig. 2 to 4. This safety device 20 allows moving an attached headrest 16 from a starting position to a safety position in response to a rear end impact. The starting position of the headrest 16 features sufficient distance from the head of the passenger to allow for a comfortable seating position. During a rear end impact, the headrest 16 is tilted forward so that at least a portion of the headrest 16 is closer to the backside of the head of the passenger than in the starting position. This is called the safety position of the headrest 16 and can stop a backward movement of the head relative to the body of the passenger particularly early. This reduces a risk of a whiplash injury for the passenger. The design and inner workings of the safety device 20 are illustrated especially by the sectional view of the safety device 20 according to Fig. 5 and the exploded view of an alternative design of the safety device 20 according to Fig. 11. The safety device 20 comprises a housing element 22, which is con- figured to be fixed to the backrest 14 of the seat 10. The safety device 20 also comprises a trigger element 24, which is movably mounted to the housing element 22 and which is configured to be movable between a resting position and a triggering position. For the safety device 20 shown in the figures, the trigger element 24 is designed as a movable block element. Furthermore, the safety device 20 comprises a tilting device 26 that is configured to move the attached headrest 16 from the starting position to the safety position in response to the trigger element 24 being moved from the resting position to the triggering position. In the design shown in the figures, the tilting device 26 comprises a coil spring 28 and a movable casing element 30. The case ele- ment 30 can be turned relatively to housing element 22 around a middle axis, which can be defined by a middle axis of a pin 52 by means of which the trigger element 24 is mounted to the housing element 22.

For example, the headrest 16 is attached to the safety device 20 by the up- per rod 32, which connects to the movable casing element 30. The safety device 20 itself is attached to the backrest 14 of the seat 10 by the lower rod 34. The lower rod 34 connects to a cover element 66, which is fixed to the housing element 22. The safety device 20 is designed to be mounted on the motor vehicle in an installation position defined with regard to a longitudinal vehicle direction.

The trigger element 24 is configured to be movable relative to the housing element 22 from the resting position to the triggering position by an inertia force acting on the trigger element in the longitudinal vehicle direction when the safety device 20 is mounted in the installation position. This is illustrated in the sectional views of Fig. 6 to Fig. 8 of the safety device 20. Fig. 6 shows the trigger element 24 in its resting position. The resting position of the trigger element 24 locks a holding element 36 into a retaining position. This retaining position is also shown in Fig. 6. In the retaining position, the holding element 36 is engaged to the casing element 30 by profile 38, which is preferably an involute thread profile or a triangular profile. This position of the holding element 36 holds the casing element 30 against the coil spring 28, which is preloaded in such a way that it would otherwise tilt the casing element 30 relative to the cover element 66 and housing element 22 in the di- rection as indicated by arrow 40 in Fig. 4, resulting in the movement of the headrest 16 from the starting position to the safety position.

In the case of a rear end impact, the trigger element 24 slides backward in the longitudinal vehicle direction relatively to the housing element 22 due to the inertia force acting on the trigger element 24 in the longitudinal vehicle direction. This force and the sliding direction is illustrated in Fig. 7 by arrow 68. The trigger element 24 comprises a recess 44 that corresponds to at least a section of the holding element 36. As soon as the trigger element 24 has slid sufficiently far from the resting position to the triggering position, this recess 44 allows the holding element 36 to start moving from the retaining position to the release position. These positions of the trigger element 24 and the holding element 36 are illustrated in Fig. 7 and Fig. 8. The movement of the holding element 36 towards the recess 44 is illustrated by arrow 46.

A force is applied to the holding element 36 in the retaining position by means of a spring element, by means of which the holding element 36 is movable from the retaining position to the release position with the trigger element 24 being in the triggering position. This spring element 50 is preloaded while the holding element 36 is in the retaining position and pushes the holding element 36 downward into the recess 44 of the trigger element 24. This allows for an especially fast reaction time of the safety device 20.

Alternatively, the coil spring 28 can exert enough force on the casing element 30 that it disengages the holding element 36 automatically from the casing element 36 once the trigger element 32 has been moved into the triggering position because of the involute profile 38. In this case, a spring element by means by means of which the holding element 36 is movable from the retaining position to the release position with the trigger element 24 being in the triggering position is not necessary, resulting in especially low costs for the production of the safety device 20. This leads to a disengagement of the involute profile 38 of the holding element 36 from the casing element 30 once the holding element 36 has reached the release position. The release position of the holding element 36 and the triggering position of the trigger element 24 are illustrated in Fig. 8. Due to the casing element 30 now being released, the coil spring 28 can ro- tate the casing element 30 around a middle axis of the safety device 20, which is the same axis as the middle axis of the pin 52. This rotation is illustrated by arrow 40 in Fig. 4 and arrow 48 in Fig. 8. The end position of the casing element 30 is illustrated in the sectional views of Fig. 9 and Fig. 10. Fig. 9 and Fig. 10 clearly show that the upper rod 32 is now tilted forward relatively to the lower rod 34. This corresponds to the headrest 16 being tilted forward relatively to the backrest 14, thus being in its safety position.

The safety device 20 only comprises mechanical components. There are no electrical components or active sensor components. Electrical components or active sensor components could reduce the reliability of the safety device 20. Furthermore, the inertia activated triggering of the safety device 20 has a particular fast response time to a rear end impact, especially in comparison to an electrical activated safety device. For example, with the safety device 20 a response time of less than 40ms, especially less than 20ms, can be achieved. Accordingly, a motor vehicle with such a safety device 20 is especially safe as the headrest 16 will reach the safety position before the backward movement of the head of the passenger can cause injury even in the case of a particular forceful and/or high speed rear end impact.

The overall design of the safety device 20 needs a particular small installation space. Especially the coil spring 28 allows for a small construction of the safety device 20. The safety device 20 and its tilting device 26 need to provide a sufficiently high torque such as 20 Nm to tilt the headrest 16 into its safety position sufficiently fast and with a sufficient reliability. The safety device 20 also needs to meet the regulation requirements of bearing a testing load of 890 N as indicated by arrow 18 in Fig. 1. Those requirements can be fulfilled especially well by a safety device 20 with the holding element 36 and the profile 38.

The trigger element 24 is mounted to the housing element 22 by the pin 52. The trigger element 24 has an oblong slot 54 in its middle, which allows the trigger element 24 to slide in the longitudinal vehicle direction along the pin 52. In the design of the safety device 20 according to Fig. 6 to Fig. 8, the trigger element 24 slides inside the housing element 22 when it is moving between the resting position and triggering position. For the alternative designs of the safety device 20 according to Fig. 9 and Fig. 10, the trigger element 24 is movable mounted to the housing element 22 by means of at least one rolling element 56. For the design of the safety device 20 according to Fig. 9, those rolling elements 56 are configured as ball elements, that act as a bearing for the trigger element 24. This allows the trigger element 24 to move between its resting position and its triggering position with particular small resistance and/or friction. This allows the trigger element 24 to react faster to a rear end impact. This also results in a particular small reaction time of the safety device 20. Furthermore, the safety device 20 can also be activated by particular small inertia forces.

Also, the trigger element 24 and the holding element 36 are movably mount- ed to each other by means of at least one other rolling element 58. This other rolling element 58 reduces the friction between the holding element 36 and the trigger element 24 when they are moving relative to each other and between their respective positions. Again, this increases reliability and decreases the reaction time of the safety device 20.

The coil spring 28 can apply strong loads on the connections between the different members of the safety device 20. These loads could possible jam a safety device 20 or increase its reaction time to a rear end impact without the rolling elements 56 and 58.

In the design of the safety device according to Fig. 10, the rolling elements 56 and 58 are not designed as ball elements but rather as barrel elements. The advantageous of the barrel elements are similar to those of the ball elements.

The safety device 20 also comprises a control element 60, by means of which a threshold value for the inertia force acting on the trigger element 24 can be determined, above which the trigger element 24 is movable from the resting position to the triggering position. For example, the control element 60 can be configured as a mechanical spring element. Such a spring element can also prevent a gradual creeping of the trigger element 24 from the resting position to the triggering position due to inertia forces below the threshold value. For example, without the control element 60, strong breaking manoeuvres could gradually move the trigger element 24 to the triggering posi- tion, finally resulting in a false activation of the safety device 20.

The tilting device 26 comprises also a locking device 62 by means of which the headrest 16 can be locked in the safety position. This means the locking device 62 will lock the position of the casing element 30 after it has been tilt- ed forward by the coil spring 28. In the shown examples, the locking device 62 is designed as a ratchet. This ratchet skips over bars 64 during movement of the headrest 16 by the tijting device 26. The bars 64 are attached to the housing element 22. This prevents a turning of the casing element 30 relative to the housing element 22 which would result in a movement of the headrest 16 from the safety position to the starting position. In order to be able to reset the headrest 16 from the safety position to the starting position, those bars 64 are detachable from the housing element 22. This allows the safety device 20 to be reusable after its activation due to a rear end impact.

Claims

CLAIMS:

1. Safety device (20) for a motor vehicle comprising:

- A housing element (22);

- A trigger element (24) being configured to be movable between a resting position and a triggering position and being movably mounted to the housing element (22);

- A tilting device (26) being configured to move an attached headrest (16) from a starting position to a safety position in response to the trigger element (24) being moved from the resting position to the triggering position,

characterized in that

the safety device (20) is designed to be mounted on the motor vehicle in an installation position defined with regard to a longitudinal vehicle direc- tion and that the trigger element (24) is configured to be movable relative to the housing element (22) from the resting position to the triggering position by an inertia force acting on the trigger element (24) in the longitudinal vehicle direction when the safety device (20) is mounted in the installation position.

2. Safety device (20) according to claim 1 ,

characterized in that

the tilting device (26) features an installation position defined with regard to the longitudinal vehicle direction and that the tilting device (26) is con- figured to move at least a portion of the attached headrest (16) forward along the longitudinal vehicle direction when the attached headrest (16) is moved from the starting position to the safety position.

3. Safety device (20) according to any one of the preceding claims,

characterized in that

the safety device comprises a control element (60), by means of which a threshold value for the inertia force acting on the trigger element (24) can be determined, above which the trigger element (24) is movable from the resting position to the triggering position.

4. Safety device (20) according to any one of the preceding claims,

characterized in that

the trigger element (24) is movably mounted to the housing element (22) by means of at least one rolling element (56).

Safety device (20) according to any one of the preceding claims, characterized in that

the safety device (20) comprises a holding element (36) that is configured to be moved between a retaining position and release position, by means of which the movement of the headrest (16) from the starting position to the safety position is blocked by the holding element (36) in the retaining position and released by the holding element (36) in the release position, whereby the movement of the holding element (36) from the retaining position to the release position is blocked by the trigger element (24) in the resting position and released by the trigger element (24) in the triggering position.

Safety device (20) according to, claim 4,

characterized in that

a force is applied to the holding element (36) in the retaining position by means of a spring element, by means of which the holding element (36) is movable from the retaining position to the release position with the trigger element (24) being in the triggering position.

Safety device (20) according to any one of claims 4 or 5,

characterized in that

the trigger element (24) comprises a recess (44) corresponding at least to a section of the holding element (36), in which the holding element (36) is at least partially movable for moving from the retaining position to the release position with the trigger element (24) in the triggering position

Safety device (20) according to any one of claims 4 to 6,

characterized in that

at least a portion of the holding element (36) features a profile, especially a wave profile and/or a saw tooth thread profile, by means of which the movement of the headrest (16) from the starting position to the safety position can be blocked by the holding element (36) in the retaining position.

Safety device (20) according to any one of claims 4 to 7,

characterized in that

the trigger element (24) and the holding element (36) are movably mounted to each other by means of at least one rolling element (58).

10. Safety device (20) according to any one of the preceding claims, characterized in that

the tilting device (26) comprises a locking device (62), by means of which the headrest (16) can be locked in the safety position, whereby the lock- ing device (62) is detachable for a reset of the headrest (16) from the safety position to the starting position.