DE102012212802A1 - Child seat for motor car, has trigger switch comprising voltage source that is integrated into seat, where voltage source is activatable such that current and/or voltage is supplied to trigger switch only after activation of voltage source - Google Patents

Abstract

The seat has a gas generator for providing an amount of gas into an inflatable structure i.e. airbag, in a release case. The structure comprises a trigger switch (1) integrated into the seat for detection of the release case and for provision of an electrical trigger signal in the release case, where the trigger signal performs the triggering of the gas generator. The trigger switch comprises a voltage source (20) integrated into the seat, where the voltage source is activatable such that current and/or voltage is supplied to the trigger switch only after activation of the voltage source.

Description

The invention relates to a child seat for a motor vehicle according to the preamble of claim 1.

A generic child seat is from the DE 94 05 366 U1 known. In this it can be provided that a head-facing side of a supporting device of a child seat is provided with an airbag which can be activated via a control device with collision sensor, wherein as collision sensor arranged in the seat electronic acceleration sensor is provided.

From the DE 10 2004 026 436 A1 is a mechanical locking and tripping device is known, which makes it possible, if necessary, a blocking effect and after lifting the lock a propellant gas mixture to flow out of a pressure vessel abruptly in order to fill an airbag system.

In general, it is known to arrange inflatable side structures (also referred to as "airpads") in a child seat which, in the event of a crash, leads to an improvement in the retention values. The necessary amount of gas can be provided by a gas generator. There is a need to provide such child seats with safe and reliable crash detection and subsequent defined ignition of a gas generator.

The present invention is therefore based on the object to provide a child seat for a motor vehicle, which enables reliable crash detection and ignition of a gas generator in the event of triggering.

This object is achieved by a child seat with the features of claim 1. Embodiments of the invention are specified in the dependent claims.

Thereafter, the solution according to the invention provides that a triggering circuit for detecting a triggering event and for providing an electrical triggering signal is integrated in the child safety seat. The triggering circuit comprises a voltage source integrated in the child seat. This can be activated in the sense that the voltage source provides current and / or voltage for the tripping circuit only after activation. The provision of an electronic trigger signal, which leads to the triggering of the gas generator, is thus not always possible, but only after activation of the triggering circuit.

The solution according to the invention provides by the integration of the voltage source in the child seat a self-sufficient, independent of the vehicle electronics protection system ready. This eliminates the need to provide contact lines to a central vehicle electronics, which is associated with a cost reduction.

The inventive design of the triggering circuit as activatable triggering circuit in the sense that the voltage source provides current and / or voltage for the elements of the triggering circuit only after activation, it is also ensured that the built-in seat energy source or voltage source has a long life , In the non-activated state, no current or no power is provided by the voltage source even when accidentally triggering a switching signal by an acceleration switch, for example, due to a jerky movement on the child seat not inserted into the motor vehicle. As a result, the reliability of the crash detection is further increased, since the ignition of the gas generator is excluded in the non-activated state of the child seat.

According to one embodiment of the present invention, the triggering circuit comprises an activation unit with at least one activation switch, in the switching of which the triggering circuit is activated. Depending on the switching state of the activation unit or its activation switch, the trigger circuit is activated or not. The triggering circuit has two states insofar; the activated state and the non-activated state.

According to one embodiment variant, provision is made for the at least one activation switch of the activation unit to be automatically connected to a vehicle when the child seat is connected to at least one holding element of a fastening system for connecting the child seat and the triggering circuit can thereby be activated. Such a vehicle-side arranged holding element is formed for example by a vehicle-side ISOFIX interface. The triggering circuit is thus activated by engaging the child seat on a vehicle-side ISOFIX interface. ISOFIX interfaces are known to those skilled in the art, so that will not be discussed further.

Alternatively or additionally, it may also be provided that the at least one activation switch is a manually operated switch arranged on the child seat, in the case of which the triggering circuit can be activated or deactivated by manual actuation thereof. In particular, it is an ON / OFF switch for activating the trigger circuit. Such a switch is for example - protected against accidental switching while driving - arranged on the back or on the bottom of the child seat.

A further embodiment of the invention provides that the child seat has means which visually indicate the activation state of the triggering circuit. Such a visual display is provided, for example, by an indicator in a control window.

It can be provided that such a display mechanically by a (also mechanical) activation switch, z. B. a manually operable ON / OFF switch, and / or when connecting the child seat with a vehicle-side holding element, in particular when locking the child seat on a vehicle-side ISOFIX interface, can be actuated. The control window is preferably attached well visible on the child seat. It can be mechanically connected to a manual activation switch and / or with a part of the child seat, for example via a Bowden cable, which is displaced or deflected when connecting the child seat with a holding element arranged on the vehicle side. Due to the mechanical connection of the display of the control window with, for example, an ISOFIX interface and / or an ON / OFF switch, a mechanical control display can be provided in a simple manner.

The triggering circuit has at least one accelerator switch disposed in the child seat, which provides an electrical switching signal when an acceleration occurs, without consuming electrical energy. The acceleration switches are thus designed so that they do not consume electrical energy. Such acceleration switches are known. They usually comprise a test mass on which an inertial force acts in the acceleration case. The acceleration switch can have a specially adapted to a child seat switching threshold.

It can also be provided that a plurality of acceleration switches are arranged in the child seat, which are aligned differently and thereby in a position to detect a crash direction, so that a targeted inflation of one or more inflatable structures in the child seat is made possible by the gas generator. Such direction-oriented acceleration switches ensure reliable triggering of the restraint protection system in the event of a crash.

The triggering circuit is preferably designed to generate an electrical trigger signal for triggering the gas generator in the activated state in the presence of a switching signal provided by an acceleration switch or in the presence of a plurality of such switching signals.

According to one embodiment variant, the triggering circuit has means for the time extension of a switching signal provided by an acceleration switch. The duration of the analog switching signal provided by an acceleration switch is characterized by the severity of the respective accident. The duration may only be a few microseconds. For a reliable ignition of the gas generator is preferably carried out an extension of the switching signal by the trigger circuit.

For this purpose, it can be provided that the triggering circuit is designed as an electronic self-holding circuit. Such self-holding circuits are known per se and are characterized by the fact that with a short switching command a long-lasting state change is triggered. According to one embodiment of the invention, the electronic latching circuit comprises a capacitor having an actuator, e.g. a gas generator, even after elimination of a provided by an acceleration switch, possibly very short, switching signal supplied with power. However, a corresponding triggering function can also be realized in another way.

According to a further embodiment of the invention, the tripping circuit comprises a transistor, in particular a MOSFET, wherein in the activated state of the tripping circuit and in the presence of a switching signal provided by an acceleration switch (ie when the acceleration switch closes) the voltage provided by the voltage source is applied to the gate of the transistor, which makes it conductive. The switching signal of one or more accelerator switches thus results in a voltage change and associated conduction of the transistor, thereby passing current through an actuator (e.g., a gas generator).

A further embodiment variant of the invention provides that the triggering circuit has a plurality of acceleration switches, two acceleration switches being arranged in series in at least one region of the child seat. Several switching threshold-optimized acceleration switches connected in series in the child seat can ensure that an unintentional violent impact on just one acceleration switch does not result in false tripping. The series-connected acceleration switches can be installed horizontally or vertically to each other. Tripping only occurs if critical acceleration values affect the entire child seat.

According to a further embodiment of the invention, at least one acceleration switch in a right side cheek and at least one acceleration switch in the left side cheek of the child seat is arranged, these acceleration switches are oriented differently. In this way, a detection of the crash direction and thus a targeted inflation of one or more of the inflatable structures of the child seat is made possible.

The voltage source is, for example, a rechargeable battery or a high quality battery. The accumulator must, according to the technical state, be charged at fixed intervals. When using a battery as a voltage source, an exchange takes place according to the battery properties after a defined time.

The invention will be explained in more detail below with reference to the figures of the drawing with reference to several embodiments. Show it:

1 a first embodiment of a tripping circuit integrated in a child seat for detecting a triggering case and for providing an electrical triggering signal;

2 a second embodiment of a built-in child seat trigger circuit for detecting a trigger case and for providing an electronic trigger signal;

3 exemplary and schematically possible installation positions of acceleration switches in a child seat;

4 an embodiment of a mechanical coupling of a display in a control window with a standard locking element of an ISOFIX mechanism;

5 an embodiment of a mechanical coupling of a display of a control window with an ON / OFF slide switch;

6 a further embodiment of an integrated in a child seat release circuit, wherein a plurality of acceleration switches are connected in series, and schematically the arrangement of a gas generator and inflatable structures in a child seat;

7 a further embodiment of a built-in child seat trigger circuit with a plurality of series-connected acceleration switches; and

8th the waveform of an electrical trip signal for triggering a gas generator based on an embodiment.

The 1 shows an embodiment of a triggering circuit which is used in a child seat for a motor vehicle and the detection of a triggering case and the provision of an electrical trip signal in the event of triggering, wherein in case of triggering a likewise integrated into the child seat inflator gas quantity for at least one inflatable structure of the child seat provides. The type of gas generator used is not important. For example, the gas generator may be a pyrotechnic gas generator, a compressed gas generator or a hybrid gas generator.

The integrated with all their components in the child seat trigger circuit 1 includes an activation unit 10 , a voltage source 20 , two acceleration switches 31 . 33 and a circuit part realizing an electronic latch circuit and including a capacitor C, a resistor R (T) and a transistor T. The transistor T is, for example, a MOSFET. On the operation of this self-holding circuit will be discussed below. Connected to the circuit is an actuator R (V), for example a gas generator.

The activation unit 10 includes two series-connected activation switches 11 . 12 , These are, for example, two switches, which are realized on the left side and on the right side of an ISOFIX interface or comparable attachment interface of the child seat. The switches are designed for example as a microswitch. The mounting brackets of the ISOFIX mounting system, which are arranged on the child seat of the ISOFIX mounting system on the vehicle side, become the switches 11 . 12 automatically closed. This ensures that the trigger circuit 1 is activated in the sense that the elements of the tripping circuit are supplied with power or voltage. In particular, it is now possible that when closing the acceleration switch 31 . 33 due to an acceleration, the circuit elements C, R (T), R (V) and T of the tripping circuit 1 be supplied with power and voltage.

Thus, by the activation unit 10 or the activation switches that form these 11 . 12 allows the trigger circuit 1 to operate in two states, a non-activated state in which the provision of an electrical triggering signal is not possible, and an activated state in which the provision of an electrical triggering signal is possible (namely, even if the acceleration switches 31 . 33 close or give a switching signal).

The acceleration switch 31 . 32 do not consume electrical energy. They preferably have a preferred direction in which an acceleration can be detected. By arranging a plurality of acceleration switches in the child seat, it is thereby possible to detect the direction of a crash or associated acceleration forces, whereby a targeted inflation of one or more inflatable structures of the child seat is made possible.

After activating the activation unit 10 and in the case of switching at least one of the acceleration switches 31 . 33 the voltage at the gate of the transistor T jumps to a voltage value dependent on the pulse length (maximum voltage source U). If this exceeds the threshold value, this causes the transistor T to become conductive and a current to flow through the actuator R (V) and the transistor T.

At the same time, during closing, at least one of the acceleration switches 31 . 33 the capacitor C charged. Closing or switching the switch 31 . 33 for a few microseconds already enough to charge the capacitor C. The charged capacitor C provides a self hold circuit in the sense as well as after opening the switches 31 . 33 (ie after elimination of the acceleration on the child seat and thus the switching signal) continues to flow through the actuator R (V) (gas generator) flows.

The 8th shows a waveform at the gate of the transistor, wherein the voltage is shown as a function of time. At time T _Z , at least one of the acceleration switches 31 . 33 closed, whereupon the voltage at the gate of the transistor T and thus also the current flow through the actuator R (V) (gas generator) increases abruptly. A slow drop in the signal curve 40 is achieved by the capacitor C and its gradual discharge. The Indian 8th voltage curve shown causes a corresponding current flow through the actuator R (V), eg gas generator. This current leads to the triggering of the gas generator.

By extending the switching signal of the acceleration switch 31 . 33 By the electronic self-holding circuit is thereby ensured that the electrical trip signal is sufficiently long to safely trigger the gas generator.

The circuit further comprises, in parallel with the capacitor C, a resistor R (T), which serves to define the discharge curve of the capacitor as independent as possible of environmental influences.

It should be noted that the transistor T operates as a power MOSFET, in particular not by a current, but only by the voltage change is switched at its gate. While the acceleration switch 31 . 33 are open, no current flows through the transistor T in the idle state.

The 2 shows an alternative embodiment of a trigger circuit 1 that differs from the embodiment of 1 only by the formation of the activation unit 10 different. In the embodiment of the 2 becomes the activation unit 10 through a mechanical switch 13 formed, which is mechanically switchable between two states. It is therefore an ON / OFF switch. This is preferred - protected against accidental switching - placed on the back or on the bottom of the child seat.

In the 3 are schematically possible installation positions of acceleration switches 31 to 33 in a child seat 2 shown. Such acceleration switches are for example in the seating area 21 , in the area of the backrest 20 and in the head area 23 of the child seat 2 educated. It may be provided that a plurality of differently oriented acceleration switch are arranged in the child seat.

The 4 shows an embodiment in which the child seat is a control window 6 for a mechanical display 61 implemented via which the activation state of the trigger circuit 1 (see. 1 . 2 ) is readable. According to the illustrated embodiment, the mechanical display 61 mechanically via a Bowden cable 7 with a standard locking stamp 8th connected to an ISOFIX mechanism. The standard locking stamp 8th includes a stamp 81 and one with this and with the Bowden cable 7 connected spring 82 , When engaging the latching arms attached to the child seat on the vehicle-side mounting brackets of the fastening system each of the stamp 81 mechanically shifted, what about the spring 82 and the Bowden cable 87 to a corresponding shift of the status display 61 leads.

As in a locking of the latching arms of the child seat on the vehicle-side mounting brackets of the fastening system and in the 1 shown activation switch 11 . 12 automatically switched, the mechanical display shows 61 on whether the trigger circuit 1 and that the protection system is activated or not.

In the embodiment of 5 is also in the child seat a control window 6 with a mechanical display 61 integrated. In this case, the mechanical indicator 61 over a Bowden cable 7 with a mechanical ON / OFF slide switch 13 connected (according to the embodiment of 2 ). The slide switch 13 has a contact 131 depending on the position of the slide switch 13 with one of two contacts 132 . 133 the trigger circuit is connected. Depending on whether a connection with the contact 132 or the contact 133 is present, the trigger circuit is activated or not. This is indicated by the ad 61 displayed.

In the 5 are the circuit elements of 2 that the acceleration switches 31 . 33 , the capacitor C, the transistor T, the resistor R (T) and the actuator R (V) comprise, simplified as a block 50 shown.

The 6 shows an embodiment of a trigger circuit, which is substantially the embodiment of the 1 and 2 equivalent. As a difference, it is provided that in two parallel arms in each case two switching threshold-optimized acceleration switch 31 - 34 are connected in series. This excludes that, for example, by an unintentional, violent shock to only one of the acceleration switch 31 - 34 it comes to a false trip. The different acceleration switches 31 - 34 together form an acceleration switch assembly 30 , The series-connected acceleration switches 31 - 34 For example, they can be arranged horizontally or perpendicular to each other.

It should be noted, however, that effective detection of a trip event and provision of an electrical trip signal can be provided even with only one acceleration switch.

6 further schematically shows the child seat 2 , in which the trigger circuit is integrated. The child seat 2 includes a seating area 21 , a backrest 22 , a head area 23 as well as side cheeks 24 that is both in the area of the backrest 22 as well as in the head area 23 extend. Such sidewalls 24 extend - based on the installed in a motor vehicle state of the child seat 2 - from the right and left sides of the backrest 22 and the head area 23 forward and can have a wall-like structure.

The 6 also shows schematically a gas generator 3 and several inflatable structures 4 , which in case of release via schematically indicated gas lines 5 with gas of the gas generator 3 be filled. Here are location of gas generator 3 and inflatable structures 4 merely to be understood as an example. For example, the gas generator instead of the head area 23 also in the area of the backrest 22 , in the seating area 21 or in the area of one of the side cheeks 24 be educated.

The inflatable structures 4 are in the illustrated embodiment on the inner sides of the side cheeks 24 educated. However, they can also be arranged in a different position and / or in a different position, for example also on the outside of the side cheeks 24 , The inflatable structures 4 can be formed in any way and are formed, for example, by inflating with a gas-inflating air cushion or deploying gas bags.

In the embodiment of 6 is provided that the acceleration switch 31 - 34 only in the area of one of the side cheeks 24 of the child seat 2 are arranged. The 7 shows an otherwise identical mode of operation, an alternative embodiment in which acceleration switch 31 - 34 and 35 - 38 in both side cheeks 24 of the child seat 2 are arranged. There are in each side cheek 24 arrangements 30 realized with two parallel line strands with two series connected acceleration switches. The greater the number of acceleration switches in the child seat, the better the direction of a crash can be detected and one or more of the inflatable structures 4 be inflated targeted by the gas generator.

The invention is not limited in its embodiment to the embodiments shown above, which are to be understood only as examples. For example, the nature of the design of the self-holding circuit is merely exemplary. The same applies to the number and arrangement of the acceleration switch. These can also be arranged in a different manner and in a different number than shown in the child seat. Also the realization of the activation unit 10 can be done in an alternative manner, for example by using other switches and / or the use of switches in conjunction with other fastening systems for child seats in the vehicle.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 9405366 U1 [0002]
• DE 102004026436 A1 [0003]

Claims (15)

Child seat ( 2 ) for a motor vehicle, comprising: - a gas generator ( 3 , R (V)) for providing a gas quantity in the event of triggering, - at least one inflatable structure ( 4 ), which in case of release with gas of the gas generator ( 3 , R (V)), and - one in the child seat ( 2 ) integrated trigger circuit ( 1 ) for detecting a triggering event and for providing an electrical triggering signal ( 40 ) in the event of triggering, which trigger the gas generator ( 3 , R (V)), characterized in that the triggering circuit ( 1 ) one in the child seat ( 2 ) integrated voltage source ( 20 ), which is designed activatable in the sense that only after activation of the voltage source ( 20 ) this current and / or voltage for the tripping circuit ( 1 ). Child seat according to claim 1, characterized in that the triggering circuit ( 1 ) at least one activation switch ( 11 - 13 ), in the switching of which the triggering circuit ( 1 ) is activated or deactivated. Child seat according to claim 2, characterized in that the at least one activation switch ( 11 . 12 ) when connecting the child seat ( 2 ) automatically switched with at least one vehicle-side holding element and the trigger circuit ( 1 ) is activated thereby. Child seat according to claim 3, characterized in that the triggering circuit ( 1 ) by snapping the child seat ( 2 ) can be activated on a vehicle-side ISOFIX interface. Child seat according to claim 2, characterized in that the at least one activation switch ( 13 ) on the child seat ( 2 ), manually operable switch is, upon its manual actuation, the trigger circuit ( 1 ) can be activated or deactivated. Child seat according to one of the preceding claims, characterized in that means ( 6 . 7 . 8th . 13 ) are provided which the activation state of the trigger circuit ( 1 ) visually. Child seat according to claim 6, characterized in that a visual indication by a display ( 61 ) in a control window ( 6 ) provided mechanically by an activation switch ( 13 ) and / or when connecting the child seat ( 2 ) can be actuated with a holding element arranged on the vehicle side. Child seat according to claim 7, characterized in that the display ( 61 ) via a Bowden cable ( 7 ) mechanically with a manual activation switch ( 13 ) and / or with a part ( 8th ) of the child seat ( 2 ), which when connecting the child seat ( 2 ) is displaced or deflected with a holding element arranged on the vehicle side. Child seat according to one of the preceding claims, characterized in that the triggering circuit ( 1 ) at least one in the child seat ( 2 ) arranged acceleration switch ( 31 - 38 ), which provides an electrical switching signal when an acceleration occurs. Child seat according to claim 9, characterized in that the triggering circuit ( 1 ) is designed, in the activated state in the presence of a by an acceleration switch ( 31 - 38 ) provided switching signal or in the presence of a plurality of such switching signals, an electrical trigger signal ( 40 ) for triggering the gas generator ( 3 To generate R (V)). Child seat according to claim 9 or 10, characterized in that the triggering circuit ( 1 ) Means (C, R (T)) for temporally extending one by an acceleration switch ( 31 - 38 ) provided switching signal. Child seat according to one of claims 9 to 11, characterized in that the triggering circuit ( 1 ) comprises a transistor (T), wherein in the activated state of the trigger circuit ( 1 ) in the presence of an accelerometer switch ( 31 - 38 ) provided a dependent on the pulse length voltage value, the maximum equal to the voltage of the voltage source ( 20 ) is applied to the gate of the transistor (T), whereby it becomes conductive. Child seat according to claim 12, characterized in that the triggering circuit ( 1 ) comprises an electronic latching circuit with a capacitor (C), which conducts a current through the transistor (T) and the gas generator ( 3 , R (V)) even after elimination of one by an acceleration switch ( 31 - 38 ) ensures provided switching signal. Child seat according to one of claims 9 to 13, characterized in that the triggering circuit ( 1 ) several Acceleration switch ( 31 - 38 ), wherein in at least one area ( 24 ) of the child seat ( 2 ) two acceleration switches ( 31 . 32 ; 33 . 34 ; 35 . 36 ; 37 . 38 ) are arranged in series. Child seat according to one of claims 9 to 14, characterized in that at least one acceleration switch ( 31 - 38 ) in a right side cheek ( 34 ) and at least one acceleration switch ( 31 - 38 ) in a left side wall ( 34 ) of the child seat ( 2 ), these acceleration switches ( 31 - 38 ) are aligned differently.

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