APPARATUS FOR DETECTING A PROPER WEARING STATUS OF A SAFETY BELT

Abstract

Apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle includes a sensor device which is at least partially disposed in or on the safety belt and configured to output a sensor value as a function of a dependency on a disposition of the safety belt. An evaluation device determines in response to the sensor value output by the sensor device, whether an occupant of the motor vehicle properly wears the safety belt.

Claims

1.-11. (canceled)

12. Apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle, said apparatus comprising: a sensor device at least partially disposed in or on the safety belt and configured to output a sensor value as a function of a dependency on a disposition of the safety belt; and an evaluation device determining in response to the sensor value output by the sensor device, whether an occupant of the motor vehicle properly wears the safety belt.

13. The apparatus of claim 12, wherein the sensor device comprises a capacitor including two electrodes, with one of the two electrodes arranged in or on the safety belt and the other one of the two electrodes forming a heating wire arrangement of a seat heater, said evaluation device determining in response to a state value measured on the capacitor, whether the occupant properly wears the safety belt.

14. The apparatus of claim 12, wherein the sensor device comprises a microphone arranged on the safety belt and configured to output a microphone signal that corresponds to a detected sound signal, said evaluation device determining in response to the microphone signal, whether the occupant properly wears the safety belt.

15. The apparatus of claim 14, wherein the sound signal includes ambient noise and/or noise of the motor vehicle.

16. The apparatus of claim 14, further comprising a loudspeaker configured to generate the sound signal.

17. The apparatus of claim 16, wherein the evaluation device is configured to determine in response to a measurement of an elapsed time of the sound signal from the loudspeaker to the microphone, whether the occupant properly wears the safety belt.

18. The apparatus of claim 16, wherein the loudspeaker is configured to transmit the sound signal cyclically.

19. The apparatus of claim 16, wherein the loudspeaker is configured to output the sound signal as an ultrasonic signal.

20. The apparatus of claim 14, wherein the evaluation device is configured to determine in response to a change in a variable characterizing the sound signal, whether the occupant properly wears the safety belt.

21. A motor vehicle, comprising an apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly, said apparatus comprising a sensor device at least partially disposed in or on the safety belt and configured to output a sensor value as a function of a dependency on a disposition of the safety belt, and an evaluation device determining in response to the sensor value output by the sensor device, whether an occupant of the motor vehicle properly wears the safety belt.

22. The motor vehicle of claim 21, wherein the sensor device comprises a capacitor including two electrodes, with one of the two electrodes arranged in or on the safety belt and the other one of the two electrodes forming a heating wire arrangement of a seat heater, said evaluation device determining in response to a state value measured on the capacitor, whether the occupant properly wears the safety belt.

23. The motor vehicle of claim 21, wherein the sensor device comprises a microphone arranged on the safety belt and configured to output a microphone signal that corresponds to a detected sound signal, said evaluation device determining in response to the microphone signal, whether the occupant properly wears the safety belt.

24. The motor vehicle of claim 23, wherein the sound signal includes ambient noise and/or noise of the motor vehicle.

25. The motor vehicle of claim 23, further comprising a loudspeaker configured to generate the sound signal.

26. The motor vehicle of claim 25, wherein the evaluation device is configured to determine in response to a measurement of an elapsed time of the sound signal from the loudspeaker to the microphone, whether the occupant properly wears the safety belt.

27. The motor vehicle of claim 25, wherein the loudspeaker is configured to transmit the sound signal cyclically.

28. The motor vehicle of claim 25, wherein the loudspeaker is configured to output the sound signal as an ultrasonic signal.

29. The motor vehicle of claim 23, wherein the evaluation device is configured to determine in response to a change in a variable characterizing the sound signal, whether the occupant properly wears the safety belt.

30. A method for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle, said method comprising: outputting a sensor value as a function of a disposition of the safety belt by a sensor device which is at least partially disposed in or on the safety belt; and determining by an evaluation device in response to the sensor value output, whether an occupant of the motor vehicle property wears the safety belt.

Description

[0029] The drawing shows in:

[0030] FIG. 1 a schematic view of an apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle;

[0031] FIG. 2 a schematic view of the apparatus, wherein a principle of capacitive detection is used;

[0032] FIG. 3 a schematic view of the apparatus, wherein a principle of acoustic detection is used;

[0033] FIG. 4 a schematic view of the apparatus shown in FIG. 3, wherein a loudspeaker is used;

[0034] FIG. 5 a schematic view of a motor vehicle with an apparatus for detecting a proper wearing status of a safety belt of a safety belt assembly; and

[0035] FIG. 6 a flowchart of steps of a method for detecting a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle.

[0036] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0037] The apparatus 10 for detecting a proper wearing status of a safety belt 12 of a safety belt assembly 14 in an unillustrated motor vehicle is shown in FIG. 1. FIG. 1 further shows an occupant 16, which sits in a vehicle seat 24 having a headrest 18, a backrest 20 and a seat cushion 22. The safety belt 12 forms a chest belt 26 which extends between an upper outer attachment point 28 and an inner attachment point 30. The inner attachment point 30 is usually designed as a belt buckle 32, in which a buckle tongue 34 is arranged, for example locked. A portion of the safety belt 12, referred to as lap belt 38, extends between the inner attachment point 30 and the lower outer attachment point 36. This arrangement of the safety belt 12 corresponds to a so-called three-point belt, with the belt buckle 32 including a knob, not shown, by means of which the occupant 16 can unlock and remove the buckle tongue 34 from the belt buckle 32 so as to enable a comfortable getting out from the vehicle seat.

[0038] Furthermore, FIG. 1 shows a sensor device 40, which is arranged at least partially in or on the safety belt and is connected by a transmission unit 42 to an evaluation unit 44. The sensor device 40 is capable of outputting at least one sensor value which is dependent on a disposition, i.e. positioning of the safety belt. For example, a sensor value for an open belt buckle 32—i.e. the occupant has not locked the buckle tongue 34 in the belt buckle 32—differs from a further sensor value for a closed belt buckle—i.e. the occupant has correctly put on a safety belt 12. The sensor value is provided via the transmission unit 42 to the evaluation device 44. The evaluation device 44 is configured to determine on the basis of the provided sensor value, whether an occupant of the motor vehicle wears the safety belt as intended. The evaluation device 44 may, for example, include means which are able to alert the occupant 16 that the safety belt 12 is not worn as intended. For this purpose, for example, warning signals, for example warning lights and/or warning sounds, can be activated and/or the motor vehicle is prevented from starting.

[0039] FIG. 2 shows the apparatus 10, wherein detection of the proper wearing status of the safety belt 12 can be realized through capacitive detection. For this purpose, an electrical capacitor or a device similar to an electrical capacitor is used in the motor vehicle. The first electrode 46 is attached to the lap belt 38, for example. The first electrode 46 may be woven into the lap belt 38 in the form of metallic fibers and/or may be applied to a fabric of the webbing of the safety belt 12 in the form of a metallic coating. A second electrode 48 associated to the first electrode 46 and configured as a heating wire arrangement for a vehicle seat heater is formed in the vehicle seat 24, in particular in the seat cushion 22 of the vehicle seat 24. The electrode 48 and the electrode 48 substantially oppose one another and are each connected to the evaluation device 44 via the transmission unit 42, which is designed as a cable 50, for example. As they oppose one another, the two electrodes 46 and 48 form the capacitor-like arrangement, which has an electrical capacitance. The electrical capacitance, i.e. the sensor value, depends in this embodiment inter alia on the distance between the two electrodes 48 and 46 from each other and on the material being arranged between the two electrodes 46 and 48. Thus, the capacitance of the capacitor-like arrangement as measured by the evaluation device 44 can be used to determine whether the lap belt 38 property extends around a lower body of the occupant 16 and not directly on the surface of the seat cushion 22 between the lower body of the occupant 16 and the seat cushion 22.

[0040] As also shown in FIG. 2, as an alternative or In addition, a further capacitor-like arrangement may be used in the apparatus 10 to detect capacitively whether an occupant 16 wears the safety belt 12 as intended. For this purpose, a further electrode 52 can be arranged in and/or on the chest belt 26. A further seat heating mat or electrode 54 may be integrated in the backrest 20 of the vehicle seat 24 to form with the associated electrode 52 a further capacitor-like arrangement. The seat heating mat or electrode 54 and the electrode 52 are each connected to the evaluation device 44 via a cable 50. As the evaluation device 44 measures the electrical capacitance of the capacitor-like arrangement formed by the electrodes 52 and 54, it can be determined whether the safety belt 12 extends on the upper body of the occupant 16 and not on the back of the occupant 16 between the upper body of the occupant 16 and the backrest 20 of the vehicle seat 24. Measuring the electrical capacitance of the capacitor-like arrangements of the apparatus 10 by means of the evaluation device 44 can be established, for example, by applying an alternating voltage to the capacitor-like arrangement and measuring the current flow. Since the electrical capacitance and the current flow in an ΔC circuit are directly proportional to each other, the capacitance of the capacitor-like arrangement can be determined by using simple physical formulas.

[0041] FIG. 3 shows the apparatus 10, in which the sensor device 40 can have at least one microphone or belt microphone 56 arranged on the safety belt. The belt microphone 56 is configured to detect a sound signal 58 and to output a microphone signal in correspondence with the sound signal 58. The microphone signal is provided via the transmission unit 42 to the evaluation device 44. The evaluation device 44 is configured to evaluate the microphone signal as to whether the safety belt 12 is disposed as intended around the occupant 16. This means that when the safety belt 12 is disposed as intended around the occupant 16, a first microphone signal is generated by the belt microphone 56 in response to the sound signal 58 and differs from a second microphone signal, which is generated by the belt microphone 56 in response to the sound signal 58 when the safety belt 12 is incorrectly worn or not worn at all by the occupant 16.

[0042] The sound signal 58 may include an ambient noise and/or a noise of the motor vehicle. This means that, in particular during travel of the motor vehicle, noises which are generated, for example, by an operation of an engine of the motor vehicle and/or by tires of the motor vehicle rolling on the roadway, penetrate into an interior of the motor vehicle. These sounds that have propagated into the interior of the motor vehicle can be detected by the belt microphone 56 and converted into the microphone signal. When the evaluation device 44 determines that the sounds that have migrated into the interior of the motor vehicle are to be classified as particularly quiet, then the evaluation device 44 determines that the occupant 16 has not property put on the safety belt 12.

[0043] FIG. 4 shows the possibility in the apparatus 10 to generate the sound signal 58 by at least one loudspeaker 60 of the motor vehicle. As the sound signal 58 is actively generated by the loudspeaker 60, the evaluation device 44 can implement an elapsed time measurement, involving a measurement of the time that elapses between generation of the sound signal 58 by the loudspeaker 60 until detection of the sound signal 58 by the belt microphone 56. Based on the elapsed time measurement, the evaluation device 44 is able to determine a distance lying between the loudspeaker 60 and the belt microphone 56. As a result, the evaluation device 44 can determine whether the safety belt 12, in particular the chest belt, is being used properly by the occupant 16. When also using a belt microphone 56 on the lap belt 38, the evaluation device 44 is able to determine whether the lap belt 38 is properly used by the occupant 16.

[0044] Furthermore, in the apparatus 10, the loudspeaker 60 may be controlled such that the sound signal 58 is outputted cyclically, i.e. recurrently. As a result, a proper wearing status of the safety belt 12 can be checked not only once, for example immediately after having buckled up, but over the entire duration during which the occupant 16 should be buckled up.

[0045] Furthermore, the sound signal 58 may be formed as an ultrasonic signal. Because the human ear cannot perceive sound signals in the ultrasonic range, the apparatus 10 can be used in a motor vehicle without adversely affecting comfort for the occupant 16. Furthermore, the sound signal 58 formed as an ultrasonic signal can be generated by the loudspeaker 60, wherein the loudspeaker 60 can be part of an interior monitoring device of an anti-theft alarm system of the motor vehicle for example. It is, however, also conceivable for the loudspeaker 60 to be part of an infotainment system of the vehicle. The belt microphone 56 is tuned to the frequency range in which the loudspeaker 60 generates the sound signal 58, so that the belt microphone 56 is able to detect the sound signal 58 generated by the loudspeaker 60.

[0046] Moreover, the evaluation device may be able to determine at least one of the variables that characterize the sound signal 58 and to determine on the basis thereof whether the occupant 16 wears the safety belt 12 as intended. A variable that characterizes the sound signal 58 may be an amplitude or a frequency of the sound signal 58. When the sound signal 58 generated by the loudspeaker 60 encounters an obstacle, a sound signal may reach the belt microphone 56 which sound signal differs in its amplitude and/or frequency from the generated sound signal 58. In other words, the sound signal 58 may be attenuated and/or diffracted before being detected by the belt microphone 56. The evaluation device 44 is configured to determine, based on a diffraction or attenuation of the sound signal 58, whether the occupant 16 wears the safety belt 12 as intended. For example, the sound signal 58 is attenuated before being detectable by the belt microphone 56, when the occupant 16 passes the safety belt 12, in particular the chest belt 26, behind the back of the occupant 16, i.e. between the occupant 16 and the vehicle seat 24. As an alternative or in addition, the sound signal 58 may be attenuated and/or diffracted when the occupant 16 has placed the lap belt 38 directly on the seat cushion 22 of the vehicle seat 24, so that the occupant 16 sits on the lap belt 38.

[0047] FIG. 5 illustrates a motor vehicle 62, which includes an apparatus 10 for detecting a proper wearing status of a safety belt 12 of a safety belt assembly.

[0048] FIG. 6 shows a method for recognition of a proper wearing status of a safety belt of a safety belt assembly in a motor vehicle. In this method, a first step S1 involves output of at least one sensor value, which is dependent on the safety belt disposition, by means of a sensor device that is arranged at least partially in or on the safety belt, and a second step S2 involves determination by an evaluation device based on the sensor value output as to whether an occupant of the motor vehicle wears the safety belt as intended.

LIST OF REFERENCE NUMBERS

[0049] 10 apparatus [0050] 12 safety belt [0051] 14 safety belt assembly [0052] 16 occupant [0053] 18 headrest [0054] 20 backrest [0055] 22 seat cushion [0056] 24 vehicle seat [0057] 26 chest belt [0058] 28 upper outer attachment point [0059] 30 inner attachment point [0060] 32 belt buckle [0061] 34 buckle tongue [0062] 36 lower outer attachment point [0063] 38 lap belt [0064] 40 sensor device [0065] 42 transmission unit [0066] 44 evaluation unit [0067] 48 electrode [0068] 48 electrode or seat heating mat [0069] 50 cable [0070] 52 electrode [0071] 54 electrode or seat heating mat [0072] 56 microphone [0073] 58 sound signal [0074] 60 loudspeaker [0075] 62 motor vehicle.