Seat belt retractor capable of detecting the presence of a rear-facing restraint device

Abstract

The invention relates to a seat belt retractor capable of detecting the presence of a rear-facing restraint device. The seat belt retractor (2) according to the invention comprises means for allowing the retraction and extension of a seat belt (6). The seat belt retractor (2) is notable in that it comprises means for detecting the extension (22) of the seat belt (6) beyond a normal length, and the detection means (22) are capable of transmitting an alert indicating the presence of a rear-facing restraint device (16) to a control unit (26) of a safety airbag when the seat belt (6) is extended beyond its normal length. Figure 2

Description

Title of the invention: Seat belt retractor capable of detecting the presence of a rear-facing restraint device. Technical field to which the invention relates

[0001] The present invention relates to the technical field of the automotive industry. More particularly, the present invention relates to a seat belt retractor for motor vehicles. Technological background

[0002] In the field of the automotive industry, regulations require the presence of safety devices in motor vehicles, in order to best preserve the integrity of their occupants during an accident.

[0003] Among the various types of existing safety devices, seat belts and safety airbags, also known as airbags, play a crucial role in the event of an accident.

[0004] Seat belts are used to restrain passengers in their seats during a violent collision, while airbags are designed to cushion the impact of passengers against an element of the passenger compartment of a motor vehicle.

[0005] Seat belts and airbags are designed to provide optimal safety for adults. For smaller individuals, these safety systems are less suitable, and may even be dangerous for young children.

[0006] Indeed, the tension of the seat belts may be too strong for a child and cause injury to the child when the motor vehicle undergoes a violent impact.

[0007] Due to their different morphology, children will also take longer than adults to impact an airbag. This delay can be detrimental to the child because the pressure inside the airbag can decrease rapidly before the child is actually inflated.

[0008] In order to overcome the lack of adaptability of the safety devices mentioned above, Regulations require the use of a child restraint device, also known as a car seat, until children are 10 years old.

[0009] For younger children, regulations specifically require the use of a rear-facing child restraint system, where the child sits facing backward. This position significantly reduces the risk of head and neck injuries in a frontal collision.

[0010] However, a rear-facing restraint system has the disadvantage of requiring the backrest of the restraint system to be positioned close to the backrest of another seat in the The deployment of a safety airbag from the seat back or dashboard can violently impact the back of a rear-facing child restraint system. The airbag can then violently push the restraint system away, seriously injuring the child seated in it.

[0011] It is therefore essential to be able to detect the presence of a rear-facing restraint device in a motor vehicle, in order to prevent violent movement of said restraint device when a safety airbag is triggered. Object of the invention

[0012] To achieve this objective, the invention proposes a seat belt retractor comprising means for enabling the winding and unwinding of a seat belt.

[0013] The seat belt retractor is notable in that it includes means for detecting the unwinding of the seat belt beyond a normal length, and in that the detection means are capable of transmitting an alert indicating the presence of a rear-facing restraint device to a control unit of a safety airbag when the seat belt is unwinded beyond the normal length.

[0014] The normal length is chosen to correspond to the seat belt extending beyond a length sufficient to restrain an adult in a motor vehicle seat. Preferably, the normal length is less than the minimum length of a seat belt required to secure a rear-facing child restraint system to a motor vehicle seat. For example, the normal length is between 1 m and 2 m.

[0015] According to another embodiment of the invention, the detection means are configured to transmit the alert to the airbag control unit when the seat belt is extended beyond a normal length and beyond a predefined adjustment time. Preferably, the adjustment time is equal to or greater than 1 minute.

[0016] According to another embodiment of the invention, the detection means comprise a mark present on the seat belt as well as a device for detecting the appearance of the mark.

[0017] By way of non-limiting example, the mark may be a coloured pattern and the detection device may be an optical detection device capable of identifying the passage of the coloured pattern.

[0018] According to another example, the mark can be a magnetic element and the detection device can be a device for detecting the magnetic field emitted by said magnetic element.

[0019] According to another embodiment of the invention, the detection means comprise a device for measuring the quantity of seat belt present in the retractor. By “quantity,” we mean, for example, a measurement of the length of seat belt present in the retractor.

[0020] According to another embodiment, the measuring device includes a distance measuring sensor between said measuring device and the seat belt. By way of non-limiting example, the distance measuring sensor may be an optical measuring sensor or an ultrasonic measuring sensor.

[0021] Of course, the different features, variants and embodiments mentioned above can be combined with each other in various ways, provided that they are not incompatible or mutually exclusive.

[0022] The invention also relates to a safety device for a passenger in a motor vehicle, comprising a safety airbag whose deployment is controlled by a control unit, the control unit is connected to a seat belt retractor as described above, and the control unit is configured to prevent the deployment of the safety airbag or to modify the inflation of the safety airbag, from the moment when the detection means of the seat belt retractor transmit to said control unit an alert indicating the presence of a rear-facing restraint device.

[0023] According to another embodiment of the invention, the safety device includes seat belt pretensioning means whose characteristics can change after receiving an alert issued by the detection means.

[0024] The invention also relates to a motor vehicle comprising a safety device as described above. Description of the figures

[0025] The invention will be better understood from the following description, which relates to preferred embodiments, given by way of non-limiting examples, and explained with reference to the accompanying schematic drawings, in which:

[0026] [Fig-1] illustrates a side view of a first mode of use of a seat belt retractor according to the invention;

[0027] [Fig.2] illustrates a side view of a second mode of use of a seat belt retractor according to the invention. Detailed description of the invention

[0028] As a reminder, the invention proposes a seat belt retractor capable of detecting the presence of a rear-facing restraint device in a motor vehicle, in order to to prevent violent displacement of said restraint device during the deployment of a safety airbag.

[0029] Figure 1 illustrates a non-limiting embodiment of a seat belt retractor according to the invention. The seat belt retractor 2 consists of a housing 4 comprising a spring-loaded belt winding shaft. The winding shaft is configured to allow the winding and unwinding, at will, of a seat belt 6 attached at one end to the winding shaft.

[0030] As illustrated by [Fig.1], the safety belt 6 includes a locking tab 8, suitable for inserting into a safety loop 10 fixed to a seat 12 of a motor vehicle, in order to allow the restraint of an adult-sized passenger 14 on said seat, according to a first mode of use of the invention.

[0031] According to a second use of the invention illustrated by [Fig.2], the safety belt 6 is unrolled so as to allow a rear-facing restraint device 16 to be held on the seat 12. More specifically, the safety belt 6 is positioned so as to rest on an upper part of the backrest 18 of the rear-facing restraint device 16.

[0032] Advantageously, the seat belt 6 includes a mark 20 in the form of a light-reflecting pattern, positioned along the seat belt 6 so as to be visible to an optical detection device 22 present in the passenger compartment of a motor vehicle, only when the seat belt 6 is holding a rear-facing restraint device 16 to the seat 12.

[0033] The mark 20 can be positioned along the seat belt 6 so as to be detected by the optical detection device when between 1 and 2 meters of said belt are unrolled.

[0034] The optical detection device 22 includes a control unit 24, configured to detect the presence of the mark 20 outside the housing 4. The control unit is connected to a control unit 26 of a safety airbag not shown in the figures. The term "connected" means the ability for two elements to exchange information.

[0035] Advantageously, the control unit 24 is configured to transmit an alert to the airbag control unit 26 when the control unit 24 detects, via the optical detection device 22, the appearance of the mark 20 during the unwinding of the seat belt 6.

[0036] The control unit 26 is configured to prevent the deployment of the safety airbag in the event of a collision involving the motor vehicle including the seat 12, so as to prevent a violent and uncontrolled displacement of the rear-facing restraint device 16 by the safety airbag.

[0037] Advantageously, the safety retractor allows a safety device, in this case an airbag, to be deactivated if a rear-facing child restraint system is present near said airbag. The invention thus increases the safety of a child when placed in this rear-facing restraint system in a vehicle equipped with an airbag.

[0038] Obviously, the control unit 24 is preferably connected to the control unit or control units of the safety airbags that are closest to the rear-facing restraint device 16, held to the seat 12 by the safety belt 6.

[0039] According to an alternative embodiment not shown, the belt may include a magnet positioned along the seat belt, so that its presence can be detected by appropriate detection means, so that the control unit 24 can transmit an alert to the airbag control unit 26 in order to prevent its deployment.

[0040] According to one embodiment, the control unit 24 can be configured to transmit the warning message to the command unit 26 after a predefined adjustment time, during which the mark 20 or the magnet is detected by the detection device. This time period can correspond to the average time it takes a passenger to adjust their seat belt. By way of non-limiting example, this time period can be equal to or greater than 1 minute.

[0041] According to another embodiment of the invention, the control unit 26 of the airbag can be configured to modify at least one of the following operating parameters of said airbag, when the control unit receives an alert message from the control unit 24:

[0042] - the time interval between a command to deploy the airbag and the actual deployment of said cushion;

[0043] - pressure and / or flow rate of the gas injected into the safety cushion to allow its deployment ;

[0044] - shape and / or dimensions of the safety cushion when deployed.

[0045] According to an alternative embodiment of the invention, the control unit 24 can also be connected to a pretensioning device not shown in the figures, allowing control of the pretension of the seat belt 6. The pretensioning device is configured to modify the strength of the pretension of the seat belt 6 and / or the time when this pretension will be effective, according to the alert transmitted by the control unit 24.

Claims

Demands

1. A seat belt retractor (2) comprising means for enabling the winding and unwinding of a seat belt (6), characterized in that it comprises means for detecting (22) the unwinding of the seat belt (6) beyond a normal length, and in that the detection means (22) are capable of transmitting an alert indicating the presence of a rear-facing restraint device (16), to a control unit (26) of a safety airbag, when the seat belt (6) is unwound beyond the normal length.

2. Seat belt retractor (2) according to claim 1, characterized in that the normal length is between 1 m and 2

3. 111. Seat belt retractor (2) according to claim 1 or 2, characterized in that the detection means (22) are configured to transmit the alert to the control unit (26) of the safety airbag, when the seat belt (6) is extended beyond a normal length and beyond a predefined adjustment time.

4. Seat belt retractor (2) according to claim 3, characterized in that the adjustment time is equal to or greater than 1 minute.

5. Seat belt retractor (2) according to any one of claims 1 to 4, characterized in that the detection means comprise a mark (20) present on the seat belt and a device for detecting the appearance of the mark (20).

6. Seat belt retractor (2) according to claim 5, characterized in that the detection device comprises an optical detection device (22).

7. Seat belt retractor (2) according to any one of claims 1 to 6, characterized in that the detection means comprise a device for measuring the quantity of seat belt present in the retractor.

8. Seat belt retractor (2) according to claim 7, characterized in that the measuring device comprises a distance measuring sensor between said measuring device and the seat belt.

9. Safety device for a passenger in a motor vehicle, comprising a safety airbag whose deployment is controlled by a control unit (26), characterized in that the control unit (26) is connected to a seat belt retractor (2) according to any one of claims 1 to 8, and in that the control unit (26) is configured to prevent the deployment of the safety airbag or to modify the inflation of the safety airbag, from the moment when the detection means (22) of the automatic retractor transmit to said control unit (26), an alert indicating the presence of a rear-facing restraint device (16).

10. Motor vehicle characterized in that it comprises at least one safety device according to claim 9.

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