SAFETY BELT, ESPECIALLY FOR AN AIRCRAFT SEAT

Description

[0001] The present invention relates to a seat belt, in particular a seat belt for an aircraft seat.

[0002] The invention is adaptable to all types of seats, in particular economy, business, and first class seats on an aircraft and to all types of seat belts with 2, 3, 4, or 5 point attachment with or without a retractor system.

[0003] The present invention can also find an application in the field of transport vehicles (cars, buses, trains, etc.) requiring the use of a seat belt.

[0004] In the field of aircraft, the known mechanisms for closing a seat belt are standard for almost all commercial flights. These standard mechanisms comprise, in a manner known per se, a closing buckle formed by a male element and a female element capable of cooperating with each other to ensure the closing of the belt. For belts without a retractor, the male element and / or the female element can slide relative to a corresponding strap to adapt the belt to the passenger's morphology.

[0005] The fastening of seat belts is generally checked by flight crew, particularly during parking, taxiing, takeoff, and landing of the aircraft, but also in the event of turbulence and / or emergency situations. However, such visual checks are time-consuming to perform and do not ensure that the passenger unfastens their seat belt immediately after the check by the flight crew. In addition, there are potential errors associated with such visual checks carried out by a human being.

[0006] Some known devices, such as the one described in document US6737862, provide detection of seat belt closure. However, these devices do not detect the adjustment of the belt around the passenger's body.

[0007] The invention aims to effectively remedy these drawbacks by proposing a safety belt, in particular intended to be installed on an airplane seat, comprising: a closing buckle comprising a male element and a female element, a first strap connected to the male element and a second strap connected to the female element, the first strap and the second strap being capable of being attached together by means of the closing buckle being able to pass from an open state to a closed state by bringing the male element and the female element into cooperation, said seat belt further comprising: a system for detecting the closing state of the seat belt capable of generating information relating to a closing state of the seat belt, and a system for detecting the mechanical tension state of the seat belt capable of generating information relating to a mechanical tension state of at least one strap of the seat belt.

[0008] The invention thus makes it possible to automatically check the seat belt in order to determine whether the belt is fastened and whether the strap is correctly tensioned around the passenger. The invention also makes it possible to ensure that the seat belt is correctly positioned on the passenger and is not closed behind or under the passenger seated in his seat.

[0009] A seat belt representing the closest state of the art is disclosed by document US 2013 / 207442 A1.

[0010] According to one embodiment, the closure state detection system comprises: a magnetic element disposed on one of the female element and the male element of the closure loop, and a magnetic field sensor disposed on the other of the female element and the male element of the closure loop.

[0011] According to one embodiment, the magnetic field sensor, in particular the Hall effect sensor, is a magnetic switch capable of closing due to the proximity of the magnetic element when the closing loop is closed.

[0012] According to one embodiment, the sensor is of the capacitive type or an electromagnetic contactor without the need for a magnet or an electromagnetic contactor requiring a magnet, such as a reed switch.

[0013] According to the invention, the mechanical tension state detection system comprises an elastic member and a switch arranged between a portion of a strap loop and a portion of a male element or a female element, such that when a mechanical tension applied to a strap exceeds a threshold, the strap deforms the elastic member and activates the switch to indicate that the seat belt is sufficiently tight around a portion of a passenger's body. Alternatively or additionally, the mechanical tension state detection system comprises a piezoelectric sensor or a strain gauge reacting to pressure applied by a strap of the seat belt. The piezoelectric sensor or the gauge will be able to detect the deformation of the elastic member.

[0014] According to one embodiment, the elastic member is constituted by a folding rod.

[0015] According to one embodiment, the elastic member consists of at least one spring.

[0016] According to one embodiment, the elastic member is a leaf spring.

[0017] According to one embodiment, said seat belt comprises a control unit connected to the system for detecting the closure state of the seat belt and to the system for detecting a level of mechanical tension of the seat belt.

[0018] According to one embodiment, said control unit is capable of controlling a communication module, in particular wireless, to transmit information relating to the state of closure of the seat belt and / or information relating to the state of mechanical tension of the seat belt.

[0019] According to one embodiment, the control unit is configured to power up the communication module after detecting a change in state of the seat belt and to cut off a power supply to the communication module after said communication module has transmitted the change in state of the seat belt.

[0020] According to one embodiment, the control unit is configured to detect a change in mechanical voltage state only if the switch changes state for a duration greater than a threshold and if the closing loop is in the closed state.

[0021] According to one embodiment, the control unit is configured to enter a sleep mode after a predetermined period of inactivity.

[0022] According to one embodiment, said seat belt comprises a source of electrical energy, in particular a battery, to be electrically autonomous.

[0023] According to one embodiment, a capacitor is electrically connected in parallel with the electrical energy source so as to cause current consumption from the electrical energy source to avoid its passivation linked to a long period of inactivity of the electrical energy source.

[0024] According to one embodiment, the control unit integrates a counter of a number of activations of the communication module to evaluate a level of electrical energy remaining from the electrical energy source.

[0025] According to one embodiment, the seat belt comprises a stop arranged on a part of an adjustable strap so as to prevent tightening of the seat belt when no one is seated on the corresponding seat.

[0026] According to one embodiment, a fixed strap has a sufficient length to prevent the seat belt from being tightened when no one is seated on the corresponding seat.

[0027] According to one embodiment, the magnetic sensor of the seat belt closure state detection system, and the seat belt mechanical tension state detection system are arranged on the same male or female element of the seat belt.

[0028] The invention also relates to a seat comprising a safety belt as previously defined.

[0029] The invention further relates to an aircraft comprising a seat as previously defined.

[0030] The present invention will be better understood and other characteristics and advantages will become apparent upon reading the detailed description which follows, comprising embodiments given for illustrative purposes with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which: [ Fig. 1 ] There figure 1 is a schematic representation of a seat belt according to the present invention; [ Fig. 2 ] There figure 2 is a schematic front representation of a male element of a closure buckle incorporating a system for detecting the state of mechanical tension of the seat belt; [ Fig. 3 ] There figure 3 is a schematic side representation of the male element of the figure 2 ; [ Fig. 4] [Fig. 5 ] THE figures 4 et 5 are schematic representations of alternative embodiments of the mechanical tension state detection system of the seat belt; [ Fig. 6 ] There figure 6 is a diagram of operating steps of a seat belt according to the present invention; [ Fig. 7 ] There figure 7 is a schematic representation of a three-point type belt integrated into a seat, particularly an airplane seat.

[0031] It should be noted that, in the figures, the structural and / or functional elements common to the different embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0032] There figure 1 shows a seat belt 10, in particular intended to be installed on an airplane seat, comprising a closing buckle 11 comprising a male element 12 and a female element 13, as well as a first strap 15 connected to the male element 12 and a second strap 16 connected to the female element 13.

[0033] The first strap 15 and the second strap 16 are made of fabric. The first strap 15 and the second strap 16 are capable of being attached together by means of the closing buckle 11 which can pass from an "open" state to a "closed" state by bringing the male element 12 and the female element 13 into cooperation. The male element 12 and / or the female element 13 can slide relative to a corresponding strap 15, 16 to adapt the belt to the morphology of the passenger.

[0034] A system 18 for detecting the closure state of the seat belt 10 is capable of generating information relating to the closure state of the seat belt 10.

[0035] For this purpose, the closed state detection system 18 comprises a magnetic element 19, such as a magnet, arranged on the female element 13 and a magnetic field sensor 20 placed on the male element 12. Alternatively, the structure could be reversed, that is to say that the magnetic element 19 could be arranged on the female element 13 and the magnetic field sensor 20 could be arranged on the male element 12. Alternatively, the magnetic element 20 could be a coil carrying a current.

[0036] The magnetic field sensor 20 is preferably a magnetic switch, in particular a reed switch capable of closing due to the proximity of the magnetic element 19 when the buckle 11 is in the closed state. Alternatively, the magnetic field sensor 20 is a Hall effect sensor. Alternatively, the sensor is of the capacitive type or an electromagnetic contactor without the need for a magnet. Alternatively, it would be possible to use other means of detecting the closure of the belt buckle, such as a piezoelectric sensor or a strain gauge.

[0037] Furthermore, a system 22 for detecting the state of mechanical tension of the seat belt 10 is capable of generating information relating to a state of mechanical tension of at least one strap 15, 16 of the seat belt 10. Thus, information relating to a "taut" state of the belt 10 is generated by the system 22 when the tension applied to a strap 15, 16 exceeds a threshold and the belt buckle 11 is in a closed state or information relating to a "slack" state when the mechanical tension applied to a strap 15, 16 is below the threshold.

[0038] For this purpose, as shown in the figure 2 , the mechanical tension state detection system 22 comprises an elastic member 23 and a switch 24 arranged between a portion of a strap loop 25 clearly visible on the figure 3 and a portion of the male element 12. The strap loop 25 passes inside an opening 26 provided in the male element 12 in order to secure the strap 16 with the male element 12. Alternatively, the elastic member 23 and the switch 24 are arranged on the female element 13. By integrating the system 22 on the male element 12 or the female element 13 of the belt, it is avoided to have it installed on a strap 15, 16 which creates an uncomfortable bulge for the passenger.

[0039] Thus, when a mechanical tension applied to the strap 16 exceeds a threshold, the strap loop 25 deforms the elastic member 23 and engages the switch 24, which indicates that the belt is sufficiently tight. The elastic member 23 is calibrated so as to allow the engagement of the switch 24 when the mechanical tension applied to the strap 16 exceeds a mechanical tension threshold of between 5 and 20 Newtons and for example of the order of 10 Newtons. By "of the order of" is meant a variation of plus or minus 10% around the target value. The switch 24 is deactivated when the mechanical tension applied to the strap 16 falls below the threshold. By "engagement" of the switch 24 is meant a transition of the switch 24 from a default open state to a closed state or conversely a transition from the default closed state to an open state of the switch 24.

[0040] Alternatively or additionally, the mechanical tension state detection system 22 comprises a piezoelectric sensor or a strain gauge reacting to pressure applied by a seat belt strap. The piezoelectric sensor or the gauge will be able to detect the deformation of the elastic member 23.

[0041] As can be seen on the figure 1 , the seat belt 10 may include a stop 27 arranged on a portion of an adjustable strap 15, 16 so as to prevent the seat belt 10 from being tightened when no one is seated on the corresponding seat. Thus, the stop 27 prevents the switch 24 from being activated if the straps 15, 16 are not arranged around the passenger's body, in particular in the case where the belt is arranged behind or under the passenger. The stop 27 may take the form of an added element sewn onto a strap 15, 16.

[0042] Alternatively, a fixed strap 15, 16 has a sufficient length to prevent the seat belt 10 from being tightened when no one is seated on the corresponding seat. For this purpose, a minimum length of a strap 15, 16 is greater than the distance between the closing buckle 11 and the anchor points on either side of the seat.

[0043] In the embodiment of the figures 2 et 3 , the elastic member 23 is constituted by a folding rod 28. The strap loop 25 therefore folds the rod 28 when the belt 10 is tensioned.

[0044] In the embodiment of the figure 4 , the elastic member 23 is constituted by at least one spring 29, for example of the helical type.

[0045] In the embodiment of the figure 5 , the elastic member 23 is constituted by at least one leaf spring 30.

[0046] A control unit 31 is connected to the system 18 for detecting the closing state of the seat belt 10 and to the system 22 for detecting the mechanical tension state of the seat belt 10.

[0047] The control unit 31 is capable of controlling a communication module 32, in particular wireless, to transmit information relating to the closure state of the seat belt 10 and / or information relating to the mechanical tension state of the seat belt 10. The control unit 31 is capable of detecting four states of the belt, namely the states "open", "closed", "tensioned", and "slack".

[0048] The control unit 31 is configured to power up the communication module 32 after detecting a change in state of the seat belt 10 and to cut off a power supply to the communication module 32 after said communication module 32 has transmitted the change in state of the seat belt 10.

[0049] The control unit 31 is configured to detect a change in mechanical tension state (change from the "relaxed" state to the "tensioned" state or conversely change from the "tensioned" state to the "relaxed" state) only if the switch 24 changes state for a duration greater than a threshold, for example of the order of 10 seconds, and if the closing loop 11 is in the closed state.

[0050] Preferably, the belt 10 comprises an electrical energy source 34, in particular a battery, to be electrically autonomous. The battery 34 is for example a lithium battery. As illustrated in the figure 2 , a capacitor 33 is electrically connected in parallel with the battery 34 so as to cause a current consumption of the battery 34 to avoid its passivation linked to a long period of inactivity of the battery 34.

[0051] Preferably, the control unit 31 integrates a counter 37 of a number of activations of the communication module 32 to evaluate a remaining electrical energy level of the battery 34. Indeed, the communication module 32 is the most energy-consuming component of the system. Consequently, by knowing the electrical energy available in the battery 34 and by counting the number of activations of the communication module 32, it is possible to deduce therefrom the remaining electrical energy level of the battery 34.

[0052] Preferably, the magnetic sensor 20 of the system 18 for detecting the closure state of the seat belt 10, and the system 22 for detecting the mechanical tension state of the seat belt 10 are arranged on the same male element 12 or female element 13 of the seat belt 10. This makes it possible to facilitate the electrical connections with the control unit 31.

[0053] The following is described with reference to the figure 6 , the operating steps of the seat belt 10 according to the invention.

[0054] When the seat belt is fastened in a step 100, the magnetic switch 20 of the buckle closes, which switches a static relay which makes it possible to supply the control unit 31 with energy via the battery (see step 101). The control unit 31 also controls the relay so as to be able to control its own power supply. The static relay is for example made on the basis of a MOSFET transistor.

[0055] In the case where the seat belt is properly fastened (see step 102) and its state is different from a previous state (see step 103), the control unit 31 powers up the communication module 32 via a similar static relay. The control unit 31 then transmits the "fastened" state to the communication module 32. The wireless communication module 32 transmits, in a step 104, the fastened status to a communication module 32 which sends it to a centralized system. Once the sending has been carried out, the control unit 31 cuts the power supply to the communication module 32 in order to save energy. Otherwise, the communication module 32 transmits a "not fastened" state in a step 105 and the system is deactivated in a step 106.

[0056] If the seat belt is fastened, the control unit 31 calculates, in a step 107, a closing time of the mechanical tension switch 24. If this time is greater than a predetermined time, for example of the order of 10 seconds, the control unit 31 then detects a "tight" state of the seat belt 10. The control unit 31 powers up the communication module 32 and transmits the "tight" state to said communication module 32 in a step 108. The wireless communication module 32 then transmits this state to the centralized system. Once the sending has been carried out, the control unit 31 cuts off the power supply to the communication module 32.

[0057] The control unit 31 then calculates the duration of opening of the mechanical tension switch 24. If this duration is greater than a predefined duration, for example of the order of 10 seconds, the control unit 31 then detects the "relaxed" state of the belt in a step 109. The control unit 31 powers up the communication module 32, and transmits the relaxed state to the communication module 32. The wireless communication module 32 in turn transmits it to the centralized system. Once the transmission has been carried out, the control unit 31 cuts off the power supply to the communication module 32.

[0058] Throughout the power supply period of the control unit 31, at each step transition and during the steps of calculating the closing or opening time of the mechanical tension switch 24, the control unit 31 checks whether the magnetic looping switch 20 is still closed. If this is no longer the case, i.e. if the closing loop 11 is open, the control unit 31 powers up the communication module 32 and transmits the "unlooped" status to it. The wireless communication module 32 in turn transmits this status to the centralized system. Once the sending has been carried out, the control unit 31 cuts the power supply to the communication module 32. The control unit 31 then cuts its own power supply and will resume operation during a new looping.

[0059] It should be noted that the activity of the belt is preferably supervised in a step 110. The control unit 31 is configured to switch to a standby mode in a step 111 after a predetermined period of inactivity, for example of the order of 2 seconds. This minimizes the electrical consumption of the system. The system becomes active again in a step 112 as soon as a change of state occurs linked to the unbuckling, tightening, or loosening of the belt in a step 113.

[0060] The preceding description was made for a seat belt 10 with two attachment points comprising two straps 15, 16 surrounding a portion of a passenger's body at the level of his pelvis.

[0061] In the embodiment of the figure 7, a seat provided with a three-point fastening belt comprises, in addition to the first strap 15 and the second strap 16, a third strap 36 associated with a second male element 12' to hold the passenger at shoulder level. In this case, the first male element 12 comprises a system 18 for detecting the state of closure of the seat belt, and a system 22 for detecting the state of mechanical tension of the seat belt. The second male element 12 may comprise only a system 18 for detecting the state of closure of the seat belt.

[0062] A sensor 38 may also be provided for detecting the presence of the passenger on the seat or on the seat belt buckle. This sensor 38 is arranged inside a seat cushion 39 of the seat or on the seat belt buckle to be able to determine whether a passenger is present on the seat. When present on the seat buckle, this sensor 38 may for example take the form of an accelerometer, a capacitive sensor, or any other sensor suitable for the application. When present on the seat cushion, this sensor 38 may for example take the form of an accelerometer, a capacitive sensor, a piezoelectric sensor, a strain gauge, or any other sensor suitable for the application.It will thus be possible, in particular during the take-off and landing phases of the aircraft, to emit a signal to a crew member or passenger in the event that the presence of a passenger in his seat is detected but the seat belt 10 is not correctly tensioned. This could mean that the passenger has inadvertently sat on the belt 10 and it is therefore necessary to alert him to avoid any risk to his safety.

[0063] The invention also relates to an aircraft comprising a seat with two or three attachment points as previously defined.

Claims

1. A safety belt (10), in particular for an aircraft seat, comprising: - a closing buckle (11) comprising a male element (12) and a female element (13), - a first strap (15) connected to the male element (12) and a second strap (16) connected to the female element (13), - the first strap (15) and the second strap (16) being able to be attached together by means of the closing buckle (11) which can pass from an open state to a closed state by bringing the male element (12) and the female element (13) into cooperation with one another, wherein said safety belt (10) further comprises: - a system (18) for detecting the closing state of the seat belt (10) and for generating information relating to a closing state of the seat belt (10), and - a system (22) for detecting the state of mechanical tension of the seat belt (10) and for generating information relating to a state of mechanical tension of at least one strap of the seat belt (10), - the system (18) for detecting the closing state comprising: - a magnetic element (19) arranged on one of the female element (13) and the male element (12) of the closing buckle (11), and - a magnetic field sensor (20) arranged on the other of the female element (13) and the male element (12) of the closing buckle, - the magnetic sensor of the system (18) for detecting the closing state of the seat belt (10), and the system (22) for detecting the state of mechanical tension of the seat belt (10) being arranged on the same male or female element of the seat belt (10), - the system (22) for detecting the mechanical tension state comprising an elastic member (23) and a switch (24) arranged between a portion of a strap buckle and a portion of a male element (12) or female element (13), such that when a mechanical tension applied to a strap (15, 16) exceeds a threshold the strap deforms the elastic member (23) and triggers the switch (24) to indicate that the seat belt (10) is sufficiently tight around a portion of a passenger's body.

2. The safety belt according to claim 1, characterized in that the magnetic field sensor (20) is a magnetic switch (24) capable of closing due to the proximity of the magnetic element (19) when the closing buckle (11) is closed.

3. The safety belt according to claim 1 or 2, characterized in that the elastic member (23) is formed by a folding rod (28).

4. The safety belt according to any of the claims 1 to 3, characterized in that the elastic member (23) is formed by at least one spring (29).

5. The safety belt according to any of the claims 1 to 4, characterized in that the elastic member (23) is a leaf spring (30).

6. The safety belt according to any of the claims 1 to 5, characterized in that it comprises a control unit (31) connected to the system (18) for detecting the closing state of the safety belt (10) and to the system (22) for detecting a level of mechanical tension of the safety belt (10).

7. The safety belt according to claim 6, characterized in that said control unit (31) is capable of controlling a communication module (32), in particular a wireless one, to transmit information about the closing state of the safety belt (10) and / or information about the state of mechanical tension of the safety belt (10).

8. The safety belt according to claim 7, characterized in that the control unit (31) is configured to activate the power supply for the communication module (32) after detecting a change in state of the safety belt and to deactivate a power supply for the communication module (32) after said communication module (32) has transmitted the change in state of the safety belt (10).

9. The safety belt according to claims 1 and 6, characterized in that the control unit (31) is configured to detect a change in mechanical tension state only if the switch (24) changes its state for a duration superior a threshold and if the closing buckle (11) is in the closed state.

10. The safety belt according to any of the claims 6 to 9, characterized in that the control unit (31) is configured to switch to a standby mode after a predetermined period of inactivity.

11. The safety belt according to any of the claims 1 to 10, characterized in that it comprises a source of electrical energy (34), in particular a battery, so as to be electrically autonomous.

12. The safety belt according to claim 11, characterized in that a capacitor (33) is electrically connected in parallel with the electrical energy source (34) so as to cause a current consumption of the electrical energy source in order to avoid its passivation linked to a long period of inactivity of the electrical energy source (34).

13. The safety belt according to claims 7 and 11, characterized in that the control unit (31) integrates a counter (37) for a number of activations of the communication module (32) in order to evaluate a remaining level of electrical energy of the electrical energy source (34).

14. The safety belt according to any of the claims 1 to 13, characterized in that it comprises a stop (27) arranged on a part of an adjustable strap (15, 16) so as to prevent the safety belt from tightening when nobody is seated in the corresponding seat.

15. The safety belt according to any of the claims 1 to 13, characterized in that a fixed strap (15, 16) has such a sufficient length that the seat belt cannot be tightened when nobody is seated in the corresponding seat.

16. A seat comprising a safety belt (10) as defined according to any of the preceding claims.

17. An aircraft comprising a seat as defined according to the preceding claim.