DE102019111396A1 - Child safety seat with a seat belt pretensioning module - Google Patents

Abstract

The invention relates to a child safety seat which comprises an integrated four-point belt for restraining a child in the child safety seat, a communication interface and a pretensioning module, the pretensioning module for increasing the belt tension acting on the integrated four-point belt in response to receiving the pre-crash signal the communication interface is designed.

Description

The present invention relates to child safety seats for use in passenger vehicles such as automobiles. Disclosed are a child safety seat, a child safety system, a vehicle comprising a child safety system, a method for operating a child safety seat and a computer program product for performing a method for operating a child safety seat.

Child safety seats can be placed on a mounted seat of a passenger vehicle with or without a detachable connection to the vehicle frame or can be permanently mounted in a vehicle. Passenger vehicles are also usually equipped with seat belts that can be used to secure a child safety seat and / or a child sitting in the child safety seat, in order to prevent injuries during collisions or in other situations that involve high acceleration. Many vehicles also have integrated anchoring structures to which a child safety seat can be attached (e.g. in accordance with the ISOFIX standard).

In many newer vehicles, seat belts are additionally equipped with pretensioning modules. Shortly before an impending crash or other high acceleration, the pretensioner increases the tension of the seat belt significantly in order to facilitate early coupling of the occupant to the vehicle frame which is subject to sudden acceleration. A pretensioner is typically triggered by a controller (such as an engine control unit, ECU) that receives signals from sensors in the body of the vehicle, and can be designed to respond in a crash situation using explosive expanding gas to act to propel a piston that retracts the belt. Alternatively, pretensioners can use an electric drive or, more generally, an energy converter with a mechanical output that can act repeatedly and over a longer period of time to provide protection in the event of events other than collisions or pre-collisions.

There may be instances where a pretensioner does not efficiently reduce a person's degrees of freedom. A pretensioner mounted in a vehicle only acts on the corresponding seat belt where the pretensioner is mounted. However, many child safety seat models include a special child restraint system, such as an integrated four-point belt. In this case, the seat belts of a vehicle can only be used as an attachment for the child safety seat. If a pretensioner is triggered to increase the belt tension of a vehicle seat belt that secures a child safety seat, the corresponding seat belts of the child safety seat remain unaffected by this process. As a result, the pretensioning process can lead to a tighter fixation of the child safety seat, while the risk of inertial movement of the child within a belt slack or a slack in the seat belt of the safety seat still exists.

Summary

A child safety seat is disclosed which comprises an integrated four-point belt for restraining a child in the child safety seat, a communication interface and a pretensioning module, the pretensioning module being designed to increase the belt tension acting on the integrated four-point belt in response to the receipt of the pre-crash signal by the communication interface is.

By increasing the tension of the integrated four-point belt in response to the receipt of the pre-crash signal, the pretensioning module can tighten the integrated four-point belt, thereby reducing belt slack in the integrated pretensioning belt and thus preventing the occupant (a child seated in the child safety seat) from being connected earlier. on the sluggish frame of the accelerating (including decelerating) vehicle. In this way, the stress on the child from top performers can be reduced or minimized.

It should be noted that, in general, the vehicle can be any vehicle that can carry the child safety seat, including cars, trucks, boats, trains, or planes. It is assumed that the vehicle can be assigned a forward direction x (roll axis), a lateral direction y (pitch axis) and a vertical direction z (yaw axis). The negative forward direction is referred to herein as the reverse or opposite direction.

Likewise, the child safety seat is not limited to a specific construction. For example, the child safety seat can be adapted to accommodate a child in a sitting position, in a lying position (as can be the case with toddler carriers or baby carriers) or in a transition position (tilted) between sitting and lying down. The child safety seat is also not limited to being mounted in any particular orientation relative to the vehicle, as may be the case with seats that are adapted for mounting in the vehicle so that an occupant of the seat faces the fore or aft direction of the vehicle . Further Child safety seats can be used that can be rotated around a pivot point between an entry position and a functional position. In the entry position, the seat can be oriented sideways so that an adult can easily position the child in the seat and then rotate the seat towards the functional position in which the child is pointing in the forward or backward direction of the vehicle.

The child safety seat can be on and / or attached to a seat of the vehicle which comprises anchoring points to which the child safety seat can be connected. For example, the child safety seat may include locking mechanisms that take advantage of or are based on the conventional ISOFIX locking mechanism (or conventional ISOFIX fasteners). ISOFIX fastening devices are adapted so that they engage in corresponding anchoring points which are arranged in a line behind the area of the turning point in which the seat surface of the vehicle seat adjoins the seat backrest of the vehicle seat on which the child safety seat is to be mounted.

The preload module can be designed to react passively to the pre-crash signal. For example, the preload module may not include a processor and the pre-crash signal is a DC voltage level present according to an "on / off" scheme, the pre-crash signal directly triggering the preload actuation if it takes the “on” level (e.g. by providing the pretensioning module with a tensioning means that includes an electromechanical lock that is unlocked by the voltage corresponding to the “on” level of the pre-crash signal ), and the preload actuation is suppressed when the pre-crash signal assumes the "off" level. Alternatively, the child safety seat and / or the pretensioning module can comprise an electronic control unit comprising a processor and a memory, the memory comprising instructions, the execution of the instructions by the processor causing the pretensioning module to increase the belt tension acting on the integrated four-point belt in response to receiving the pre-crash signal through the communication interface. The communication interface is in a communicative connection (e.g. wired, wireless) with the preload module for forwarding the pre-crash signal to the preload module or for signaling the receipt of the pre-crash signal.

The pre-crash signal can be generated by appropriate hardware (which can be integrated in the vehicle and include a detection unit such as a radar system) that is specially adapted for the provision of the pre-crash signal for the child safety seat; or by existing hardware such as a collision avoidance system, a pre-crash system, a forward collision warning system or a collision mitigation system mounted in the vehicle. The pre-crash signal can be specifically intended to trigger the pretensioning module of the child safety seat. It should be noted that embodiments of the invention are considered valid only if they involve an increase in belt tension in response to receipt of a pre-crash signal or if they provide a means for increasing belt tension in response to the reception a pre-crash signal is adapted include.

As explained in more detail below, there are numerous possible ways of providing the pretensioning module with the necessary amount of energy to carry out the increase in belt tension by an order of magnitude sufficient to ensure improved protection against inertial movements of the child relative to the child safety seat. Examples include a chemical energy source (e.g. when the preload module employs pyrotechnic technology), a mechanical energy storage device (which needs to be charged, e.g. when placing, securing, assembling or using the seat in a vehicle), and / or a source for electromagnetic energy (e.g. an electric motor connected to an electrical power connector inside the vehicle). The pretensioning module is preferably adapted to increase the belt tension of the integrated four-point belt to a value between 100 Newtons and 1000 Newtons.

The voltage actuation of the biasing module in response to receiving the pre-crash signal can be subject to certain conditions. For example, the pretensioning module can only be triggered when the integrated four-point belt is properly engaged, which z. B. can be determined by using a suitable sensor or a contact voltage. If the belt is improperly fastened, further tensioning of the belt can buckle the belt, which can expose an occupant of the child safety seat to a higher risk of injury than leaving the improperly fastened belt as it is without the pretensioning module generating additional belt tension.

According to one embodiment, the pre-crash signal signals an imminent crash-induced acceleration of the child safety seat. When the child safety seat is firmly connected to the frame of the vehicle, but without it Case to be limited, the acceleration of the child safety seat can be equated with the acceleration of the vehicle. As a result, the pre-crash signal can indicate that a collision of the vehicle has a high probability of occurrence (e.g. higher than a threshold value) or is inevitable within a predetermined reference period. It should be noted that the crash-induced acceleration of the child safety seat can have a positive or negative value.

According to one embodiment, the crash-induced acceleration is imminent within less than 500 milliseconds and preferably less than 300 milliseconds. These periods are typical of the “pre-ignition phase” in passenger vehicles, during which automatically reversible measures are carried out by the car's pre-crash system, such as the use of electric belt tensioners, the adjustment of the headrests and the closing of the sunroof and windows. With a pyrotechnic preload module, the time in which the crash-induced acceleration is imminent can be even shorter (10-100 milliseconds) due to the much faster release of the preload through the use of pyrotechnics.

According to one embodiment, the pretensioning module comprises a force limiter for limiting the increase in belt tension to a predefined maximum value. A force limiter can be used in various ways, such as using an elastic element (e.g. a torsion bar in the seat belt retractor) or an energy management loop in the strap of the integrated four-point seat belt, and can provide the advantage of reducing the risk of occupant injuries caused by mechanical overloading of the upper body is reduced.

According to one embodiment, the communication interface is an “over the air” interface or a wired interface. This can facilitate the integration of the preload module with other wired or "over the air" systems that may be present in a given vehicle, and consequently it can add flexibility to the use of the preload module in vehicles that are not responsible for the proper control of the Are configured to increase the preload module.

The communication interface is preferably adapted to receive the pre-crash signal through a communication link that has a comparatively low latency. In one example, a communication link with low latency is used in the form of a cable which, in order to transmit the pre-crash signal, is set to a predefined voltage level which is specific for the pre-crash signal. In the example, the communication interface is either an active interface with a processor that controls the tension applied to the cable, or the communication interface is a passive interface and a processor of the pretensioning module controls the tension applied to the cable via the communication interface. In a further example the low latency connection uses a communication protocol and in a more specific example the low latency connection is a wireless connection according to the Bluetooth standard with aptX low latency compression.

According to one embodiment, the pretensioning module comprises one of the following means for increasing the belt tension: a pyrotechnic belt tensioner, a pretensionable elastic element (e.g. a spring, an elastic tension belt) or an electric motor. These means for performing the increase in belt tension can be suitable for generating a sufficient linear or angular momentum to ensure that a desired tension force is achieved in the short time (typically between 1 second and 100 milliseconds) between receipt of the pre-crash signal and the expected time of the collision of the vehicle or another acceleration of the child safety seat (also referred to herein as the “pre-crash period”).

Pyrotechnic preload modules typically include a chemical container containing reactants for a rapid exothermic reaction which, when triggered, is capable of amplifying during the pre-crash period. Such modules typically release gas during a controlled explosion; H. under high pressure and high temperature, in (for example) a solid hose. The linearly expanding gas then exerts an impulse on a piston, which drives the integrated four-point belt directly or via a suitable linkage (e.g. a tensioning wheel).

A pretensionable elastic element is understood here to mean an elastic element with a slight plasticity, so that a desired pretensioning force remains constant when it is exerted on the elastic element. Examples include, among others, a spring comprising a coil spring made of steel, a torsion spring made of steel, and a gas spring. In a case where the elastic member is linear, the triggered pulse can be converted into a rotation of a tensioning wheel. The elastic element can by a pawl, a bolt acting on a retaining element or another suitable mechanism adapted for unlocking within the pre-crash period, which is a electromagnetic device, such as an electrically controlled magnetic or pyrotechnic actuator, is held in its biased position.

An electric motor converts electromagnetic forces (an electric field, a magnetic field, or both) into linear impulse or angular momentum and is preferably equipped with a capacitor adapted to provide a current high enough to produce a desired tension force within the Achieve pre-crash period.

According to one embodiment, the child safety seat further comprises a lever which is arranged on the outside of a seat shell of the child safety seat, wherein the elastic element can be pretensioned by actuating the lever. This can have the advantage that no technical energy source is required to pretension the elastic element. The lever can be integrated into a portion of the seat that is used regularly, e.g. B. a seat element (so that the lever can be operated by the weight of the occupant while sitting in the seat) or a rotatable handle (e.g. if the seat is a toddler carrier).

According to one embodiment, the child safety seat further comprises a rebound bar, wherein the rebound bar is adapted to be fixedly fixed to the seat, and to form an abutment in relation to a vehicle seat on which the child safety seat is to be mounted, the lever through the rebound bar is given.

A rebound bar may be located on the supporting base, footboard, or headboard of the seat and may include a locking mechanism and an unlock button. In general, “rebound” is understood to mean the movement that occurs in response to the initial impact of a crash; d. H. in the event of a crash, two forces always occur, the initial force of the crash and the subsequent rebound that acts on the occupant. The rebound bar typically leans against the back support of the vehicle seat when the child safety seat is mounted on the vehicle seat. The rebound movement of the child safety seat in the event of a crash can be reduced via the rebound bar. Another advantage of the rebound bar can be that in the event of a rear impact with the vehicle in which the child safety system is installed, a rotation of the child safety seat in the rear direction is also controlled.

In one example, the rebound bar is arranged on the child safety seat in such a way that it can be rotated about an axis, and it can be unlocked in several positions, the lever mechanism being actuatable by the rotation. The elastic element can be charged by pressing the back support of the safety seat against the back support of the vehicle seat.

According to one embodiment, the elastic element can be pre-tensioned by using the integrated four-point belt in the child safety seat. For example, the integrated four-point belt can be wound up when the child is sitting in the seat, and the elastic element, e.g. B. a coil spring is tensioned by unwinding the belt. Using the belt to tension the pretensioner module can also reduce the risk of forgetting to manually operate the tensioner, as it can be assumed that the integrated four-point belt will be used regularly before the vehicle begins to move.

According to one embodiment, the child safety seat comprises a supporting base and a seat element, wherein the seat element provides a seat for the child in the seat, the seat element is rotatably mounted relative to the supporting base, the elastic element can be biased by the rotation of the seat element relative to the supporting base . The rotation of the seat member relative to the supporting base may be horizontal (i.e. about an axis that is parallel to the Z-axis) or vertical (e.g. about an axis that is parallel to the Y-axis). This can be a further advantageous way of charging the elastic element of the prestressing module. Using the seat element to tension the pretensioning module can also reduce the risk of forgetting to manually actuate the tension, since it can be assumed that the seat element is regularly rotated into a position suitable for driving before the vehicle begins to drive.

According to one embodiment, the seat element is horizontally rotatable from an entry position to a driving position and from a driving position to an entry position (ie around the Z-axis of the vehicle), the entry position and the driving position differing through a rotation angle of at least 45 degrees and preferably at least 80 degrees different from each other. The entry position can make it easier to position a child in the seat from one side of the seat. When the seat element is in the driving position, the child is aligned with the positive or negative forward direction of the seat.

A rotational angle of at least 45 degrees can provide a sufficiently long rotation path to efficiently reduce the force required to charge the elastic element. A use of the self-tuning function with a Rotational angles of at least 80 degrees can make it easier to position a child in the seat.

According to one embodiment, the child safety seat is an infant carrier.

According to one embodiment, the child safety seat comprises a supporting base and a seat element, the seat element providing seating for the child in the seat, the seat element being vertically rotatable through a vertical angle between the supporting base and the seat element and the actuation of the pretensioning module to adapt the vertical angle leads. The axis of vertical rotation lies within a plane that is parallel to the x-y plane of the vehicle and the vertical angle is defined between the supporting base and the seat plane. The axis of rotation is preferably parallel to the y-axis of the vehicle. Here, the prestressing force exerted by the prestressing module can be used to additionally rotate the child safety seat, in response to receiving the pre-crash signal, into an orientation that corresponds to a specific horizontal (lying) orientation of the occupant. This takes into account the observation that the collision of a vehicle usually causes an acceleration whose component, which is parallel to the x-y plane, is large compared to its z-component. After this vertical rotation, the occupant's body would consequently be oriented more parallel to the xy plane (which plane would carry the largest component of the collision pulse with it), so that a collision pulse that is absorbed by the occupant is basically along the length or Width of the occupant's body is aligned. This can reduce the risk of collision injuries caused by inertial movements of the upper body perpendicular to the x-y plane.

In a further aspect, the invention relates to a child safety system that comprises a pre-crash detection unit of a vehicle and the child safety seat according to the embodiment described herein, the pre-crash detection unit being adapted to send the pre-crash signal to the communication interface is.

A pre-crash detection unit is adapted to use one or more sensors (a sensor module) to detect an imminent impact of the vehicle in which the child safety seat is mounted with an obstacle. A crash event is considered to be imminent if it can be considered to occur (e.g. based on a measured distance between the vehicle and the obstacle and a current relative speed of the vehicle and the obstacle) within the pre-crash period defined above.

The pre-crash signal can be generated using a suitable communication link, such as a wired or wireless link that uses one or more of the following elements: a bus topology, a peer-to-peer connection, a packet-based network, a link -Layer connection, an ad hoc network, etc., can be transmitted from the detection unit to the communication interface. The communication link can be part of a network within the vehicle that is managed by an integrated collision avoidance system of the vehicle. One example of a collision avoidance system is Mercedes-Benz PRE-SAFE ^® .

The pre-crash detection unit may comprise a sensor module employing known or future sensor technology including, but not limited to, radar, lidar, an image sensor (camera), ultrasound / sonar, etc.

In a further aspect, the invention relates to a vehicle including the child restraint system according to an embodiment disclosed herein.

In a further aspect, the invention relates to a method for operating a child safety seat which comprises an integrated four-point seat belt for restraining a child in the seat, a pretensioning module and a communication interface, the method comprising receiving a pre-crash signal through the communication interface and , in response to the receipt, causes the pretensioning module to increase the belt tension acting on the integrated four-point belt.

According to one embodiment, the pre-crash signal is received by a pre-crash detection unit of a vehicle. The vehicle that includes the pre-crash detection unit can be the vehicle that carries the child safety seat.

In a further aspect, the invention relates to a computer program product comprising computer-executable instructions for performing the method, according to an embodiment disclosed herein, for operating a child safety seat.

• 1 eine schematische Betätigungsumgebung eines Kindersicherheitssitzes zeigt;
• 2 Ausrichtungen eines horizontal rotierbaren Kindersicherheitssitzes zeigt; und
• 3 ein Flussdiagramm zeigt, das Schritte eines Verfahrens zum Betätigen eines Kindersicherheitssitzes veranschaulicht.

The examples and embodiments described above can be combined as desired, as long as the individual examples and embodiments are not mutually exclusive. Embodiments of the invention are described in more detail below, wherein:

• 1 shows a schematic operating environment of a child safety seat;
• 2 Shows orientations of a horizontally rotatable child safety seat; and
• 3 Figure 3 shows a flow diagram illustrating steps in a method for operating a child safety seat.

In the following, similar elements are identified by the same reference numbers.

1 Figure 3 is a schematic illustration of an exemplary child safety seat 100 in the context of an exemplary vehicle 110 . The child safety seat 100 includes an integrated four-point belt 102 , a prestressing module 104 and a communication interface 108 . In response to receiving a pre-crash signal through the communication interface 108 is the prestressing module 104 to raise the on the integrated four-point belt 102 acting belt tension using the tensioning device 106 designed.

The child safety seat 100 For example, it may be a chair-like seat that allows an occupant (a child seated in the child safety seat) to rest in a seated position, or an infant carrier that allows an infant to rest in a lying position. The child safety seat 100 may further comprise, among others, one or more of the following: a closure 202 or an equivalent counterpart for holding a tongue or equivalent means of the integrated four-point belt 102 ; one or more sensor (s) in communicative connection with the prestressing module 104 ; Armrests 208 ; a side impact protection system or other passive safety features a headrest; a back support 101 ; one or more connecting element (s) 210 to establish a positive connection with the frame of the vehicle 110 ; a seat element 107 ; a seat shell 109 ; a supportive base 200 ; a lever 105 that is used to pretension a tensioning means 106 is adapted; a rebound bar 204 which is adapted to it, firmly on the child safety seat 100 to be fixed, and in relation to a vehicle seat on which the child safety seat 100 is to be assembled to form an abutment; and one or more hinge (s), axle (s), pivot pins or other means that allow vertical and / or horizontal rotation of one or more elements of the child safety seat 100 relative to a supportive base 200 or a vehicle seat on which the child safety seat 100 should be mounted.

The integrated four-point belt 102 may further comprise, among other things, a tongue or equivalent means adapted to be inserted into the closure 202 or an equivalent one on the housing of the child safety seat 100 to engage the fixed or attached counterpart; and / or a force-limiting agent 103 to limit the belt tension to a specified maximum force.

The prestressing module 104 comprises the tensioning means 106 and may further include, among others, one or more of the following: a force limiting agent 103 to limit the belt tension to a predetermined maximum force; and a processor (controller) which is both for receiving a pre-crash signal from the communication interface 108 , optionally for processing the pre-crash signal, as well as for actuating the voltage means 106 is adapted in response to receipt of the pre-crash signal.

The tension means 106 comprises, inter alia, means for increasing the belt tension of an integrated four-point belt 102 to a predetermined order of magnitude within the time interval between receipt of the pre-crash signal and an expected acceleration time of the child safety seat, e.g. B. due to a collision of a vehicle 110 that is the child safety seat 100 with it (the pre-crash period), including, but not limited to, a pyrotechnic belt tensioner, a pretensionable elastic element or an electric motor.

The prestressing module 104 can be operated without storing mechanical pre-tensioning energy, e.g. B. when the tension means 106 is an electric motor. In this case, the prestressing module 104 be equipped with a suitable energy storage device.

The communication interface 108 is for receiving a pre-crash signal and for providing the pre-crash signal, a notification information about the presence of the pre-crash signal and / or a control signal for activating, triggering, unlocking or actuating the preload module 104 to the prestressing module 104 customized. The communication interface 108 can be a passive interface (e.g. a socket or an antenna circuit) or an active interface that comprises an electronic communication control unit. The communication interface 108 can be adapted to receive the pre-crash signal via a wired communication link, a wireless or “over the air” communication link or an optical communication link, among other things. In one example is the communication interface 108 to designed to receive the pre-crash signal via a Bluetooth / aptX low latency connection.

The child safety seat 100 can in a vehicle 110 placed, connected to or mounted in it. In the example shown, the vehicle includes 110 a pre-crash detection unit 120 (which e.g. is part of a collision avoidance system), which is a sensor module 112 , a controller 114 and a communication interface 116 includes. The sensor module 112 may include known or future sensor technology including, but not limited to, radar, lidar, an image sensor (camera), ultrasound / sonar, etc. The controller 114 is for receiving and processing one from an output of the sensor module 112 received sensor signal, generating a pre-crash signal based on the sensor signal and forwarding (e.g. sending) the pre-crash signal via the communication interface 116 adapted to the child safety seat. The pre-crash signal can indicate an imminent crash-induced acceleration of the vehicle 110 and / or the child safety seat 100 Show. The control 114 is preferably operated so that the pre-crash signal is generated and transmitted when the sensor signal indicates that the crash-induced acceleration is imminent within less than 500 milliseconds and preferably less than 300 milliseconds.

2 Figure 12 shows first, second and third exemplary orientations of the child safety seat 100 that swivels on a supporting base 200 is appropriate. On the left will be the seat 100 and the base 200 Shown in the second relative orientation that matches the one in the seat 100 Allows the child located in the forward direction of a vehicle seat (not shown), the child safety seat 100 receives and who on the supporting basis 200 is appropriate to show. In the center of the drawing are the seat 100 and the base 200 shown in the first relative orientation that matches the one in the seat 100 Allows the child located to point to the left side of the vehicle seat (relative to the forward direction of the vehicle seat). This orientation provides “easy entry” for the child to be positioned sideways in the seat. On the right will be the seat 100 and the base 200 Shown in the third relative orientation, which allows the child to sit in the seat 100 should be located, allows to point to the backrest of the vehicle seat (ie relative to the forward direction of the vehicle seat).

The three orientations can be adjusted by rotating the child safety seat horizontally 100 relative to the supporting base 200 (indicated by curved arrows between the first and second orientations or between the first and third orientations) from one to another. The child safety seat 100 includes a mechanism (e.g. a gear mechanism, a Bowden cable or the like) for transforming rotational energy resulting from the horizontal rotation of the child safety seat 100 originates from the first (second) into the second (first) orientation or from the first (third) into the third (first) orientation, into elastic energy and for storing the transformed energy in the prestressing module 104 .

3 FIG. 12 shows a flow chart showing steps of an exemplary method for operating a child safety seat 100 illustrated. In step S302 receives a processor or a controller of the child safety seat 100 (e.g. encompassed by the communication interface 108 or the prestressing module 104 ), via the communication interface 108 , a pre-crash signal, e.g. B. by the controller 114 of the collision avoidance system is generated and via the communication interface 116 is transmitted. The pre-crash signal indicates an imminent crash-induced acceleration of the child safety seat. In response to receiving the pre-crash signal, the processor causes ( S304 ) that the tension means 106 by triggering, unlocking, activating or operating the voltage device 106 those on the integrated four-point belt 102 acting belt tension increased.

List of reference symbols

100

Child safety seat

101

Back support

102

integrated four-point belt

103

Force limiter

104

Prestressing module

105

lever

106

Tension means

107

Seating element

108

Communication interface

109

Bowl

110

vehicle

112

Sensor module

114

control

116

Communication interface

120

Pre-crash detection unit

200

supportive base

202

Clasp

204

Rebound bar

208

Armrest

210

Connecting element

300

Procedure

Claims (18)

Child safety seat (100), which comprises an integrated four-point belt (102) for restraining a child in the child safety seat (100), a communication interface (108) and a pretensioning module (104), the pretensioning module (104) for increasing the amount of the integrated four-point belt (102 ) acting belt tension is designed in response to the receipt of a pre-crash signal by the communication interface (108). Child safety seat Claim 1 , wherein the pre-crash signal indicates an imminent crash-induced acceleration of the child safety seat (100). Child safety seat Claim 2 wherein the crash-induced acceleration is imminent within less than 500 milliseconds and preferably less than 300 milliseconds. Child safety seat according to one of the preceding claims, wherein the pretensioning module (104) comprises a force limiter (103) for limiting the increase in belt tension to a predefined maximum value. Child safety seat according to one of the preceding claims, wherein the communication interface (108) is an “over the air” interface or a wired interface. Child safety seat according to one of the preceding claims, wherein the pretensioning module (104) comprises one of the following means (106) for carrying out the increase in belt tension: a pyrotechnic belt tensioner, a pretensionable elastic element or an electric motor. Child safety seat Claim 6 which further comprises a lever (105) which is arranged on the outside of a seat shell (109) of the child safety seat (100), wherein the elastic element can be pretensioned by actuating the lever (105). Child safety seat Claim 7 further comprising a rebound bar (204), the rebound bar (204) being adapted to be fixedly fixed to the seat (100) and in relation to a vehicle seat on which the child safety seat (100) is to be mounted, to form an abutment, the lever (105) being given by the rebound rod (204). Child safety seat according to one of the preceding Claims 6 - 8th wherein the elastic element can be pre-tensioned in the child safety seat (100) by using the integrated four-point belt (102). Child safety seat according to one of the preceding Claims 6 - 9 wherein the child safety seat (100) comprises a supporting base 200) and a seat element (107), the seat element (107) providing seating for the child in the seat (100), the seat element (107) being rotatable relative to the supporting base ( 200) is attached, the elastic element can be biased by the rotation of the seat element (107) relative to the supporting base (200). Child safety seat Claim 11 wherein the seat element (107) can be rotated horizontally from an entry position to a driving position and from a driving position to an entry position, the entry position and the driving position differing from one another by an angle of rotation of at least 45 degrees and preferably at least 80 degrees. Child safety seat according to one of the preceding claims, wherein the child safety seat (100) is an infant carrier. Child safety seat according to one of the preceding claims, wherein the child safety seat (100) comprises a supporting base (200) and a seat element (107), the seat element (107) provides seating for the child in the seat (100), the seat element (107) around a vertical angle between the supporting base (200) and the seat element (107) is vertically rotatable and the actuation of the pretensioning module (104) results in an adjustment of the vertical angle. Child safety system, comprising a pre-crash detection unit (120) of a vehicle (110) and the child safety seat (100) according to one of the preceding claims, wherein the pre-crash detection unit (120) for sending the pre-crash signal to the Communication interface (108) is adapted. Vehicle (110) that has the child restraint system according to Claim 14 includes. A method (300) for operating a child safety seat (100) comprising an integrated four-point belt (102) for restraining a child in the seat (100), a pretensioning module (104) and a communication interface (108), the method comprising receiving a pre- Crash signal through the communication interface (108) and, in response to the receipt, causes the Pre-tensioning module (104) increases the belt tension acting on the integrated four-point belt (102). Procedure according to Claim 16 , wherein the pre-crash signal is received by a pre-crash detection unit (120) of a vehicle (110). Computer program product comprising computer-executable instructions for performing the method (300) Claim 16 or 17th includes.

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