WO2023020976A1

WO2023020976A1 - Aeroplane cabin furniture element provided with a clamping sensor

Info

Publication number: WO2023020976A1
Application number: PCT/EP2022/072729
Authority: WO
Inventors: Jean-Marc Obadia; Lisandre MARCOVICI-SOULAGE; Raed BSILI
Original assignee: Safran Seats
Priority date: 2021-08-17
Filing date: 2022-08-12
Publication date: 2023-02-23
Also published as: FR3126212B1; FR3126212A1

Abstract

The present invention relates to a furniture element (10) for an aeroplane cabin, comprising: - a clamping component (13) and a reaction component (14) intended to be clamped against one another to secure said furniture element (10); - said furniture element (10) further comprising a clamping sensor (16) arranged between the clamping component (13) and the reaction component (14); - said clamping sensor (16) comprising a strain gauge (17) for measuring a clamping torque between the clamping component (13) and the reaction component (14); and - communication means (19) for transmitting a clamping state between the clamping component (13) and the reaction component (14).

Description

DESCRIPTION

AIRCRAFT CABIN FURNITURE ELEMENT WITH A CLAMPING SENSOR

The present invention relates to an element of aircraft cabin furniture provided with a clamping sensor. The invention finds a particularly advantageous application with all the furniture items requiring to be fixed inside an airplane cabin, such as seats of the "economy" or "business class" type, seat shells mounted around a seat to provide privacy to the passenger, luggage racks, kitchen modules, or any other piece of furniture installed inside an aircraft cabin.

[0002] In a manner known per se, locks are used to secure a seat to the fixing rails of an aircraft cabin. Other seat elements, such as business seat shells, also require tightening to a predefined torque.

[0003] Due to the vibratory environment of an airplane cabin, the seats may encounter loosening problems at the fixing locks. Significant loosening presents a danger to the passenger in the event of an accident. Slight loosening can cause seat instability or vibration noise in flight, which can therefore cause discomfort for the passenger.

[0004] The locks are sometimes sealed with paint markings to check that the screws have not come loose. Only a regular visual check can guarantee that the tightening carried out is maintained at the desired torque. However, such visual checks take a long time to perform. In addition, there are possibilities of errors related to such checks carried out by a human being.

The invention aims to effectively remedy this drawback by proposing an element of aircraft cabin furniture comprising:

- a clamping component and a reaction component intended to be clamped against each other to secure said piece of furniture,

SUBSTITUTE SHEET (RULE 26) - said piece of furniture further comprising a tightening sensor arranged between the tightening component and the reaction component,

- said tightening sensor comprising a strain gauge intended to measure a tightening torque between the tightening component and the reaction component, and

- communication means for transmitting a tightening state between the tightening component and the reaction component.

The invention thus makes it possible, thanks to the presence of the integrated tightening sensor, to carry out automatically and remotely the tightening control of the furniture element of the aircraft cabin. The invention therefore makes it possible to carry out a rapid check while avoiding the human errors that may occur within the framework of a visual procedure, which offers a gain in safety.

[0007] According to one embodiment of the invention, the means of communication are of the wireless type.

[0008] According to one embodiment of the invention, the tightening sensor is an independent sensor.

According to one embodiment of the invention, the means of communication comprise a radio-frequency transponder associated with an antenna intended to receive electromagnetic waves to electrically supply the tightening sensor and to transmit a signal representative of the tightening state .

According to one embodiment of the invention, the sensor has the shape of a washer.

According to one embodiment of the invention, said piece of furniture consists of an aircraft seat comprising a lock intended to be fixed on a fixing rail of the aircraft cabin.

According to one embodiment of the invention, the sensor is arranged between a nut constituting the clamping component and a body of the lock constituting the reaction component. According to one embodiment of the invention, the sensor is arranged between a body of the lock constituting the clamping component and the fixing rail constituting the reaction component.

According to one embodiment of the invention, said piece of furniture further comprises an additional gauge for measuring stresses exerted on the seat other than lock tightening stresses.

[0015] According to one embodiment of the invention, said piece of furniture comprises means for filtering data returned by the strain gauge and the additional gauge to dissociate tightening stresses from stresses induced by another load exerted on headquarters.

The present invention will be better understood and other characteristics and advantages will become apparent on reading the following detailed description comprising embodiments given by way of illustration with reference to the appended figures, presented by way of examples not limitations, which may be used to complete the understanding of the present invention and the description of its realization and, where appropriate, contribute to its definition:

[0017] [Fig. 1] Figure 1 is a schematic representation of an element of aircraft cabin furniture comprising a clamping sensor according to the invention;

[0018] [Fig. 2] Figure 2 illustrates an application of the invention to the control of a tightening level of locks of an aircraft seat;

[0019] [Fig. 3] Figure 3 shows graphical representations of linear or polynomial regressions that can be used to relate strain gauge deformation to corresponding tightening torque.

It should be noted that the structural and/or functional elements common to the different embodiments have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties. Figure 1 shows a piece of furniture 10 intended to be fixed on a fixed element 1 1 of an aircraft cabin. The furniture element 10 may for example take the form of a seat or seat furniture, such as a side console or a seat shell intended to extend at least in part around the seat to confer a passenger privacy. The piece of furniture 10 may also take the form of a kitchen module or a luggage rack intended to be fixed to a wall of the aircraft cabin. The fixed element 11 may take the form of a fixing rail mounted on a floor or a wall of the aircraft cabin.

The furniture element 10 comprises a clamping component 13 and a reaction component 14 intended to be clamped against each other to ensure fixing of the furniture element 10 on the fixed element 1 1 . The clamping component 13 applies a clamping force to the reaction component 14 which generates an opposing force on the clamping component 13 in reaction to the clamping. The tightening component 13 for example takes the form of a tightening nut or any other element configured to receive a tightening torque via a tool such as a tightening key manipulated by an operator.

A clamping sensor 16 whose various components are shown in detail in Figure 2 is arranged between the clamping component 13 and the reaction component 14.

The tightening sensor 16 comprises a strain gauge 17 intended to measure a tightening force or a tightening torque between the tightening component 13 and the reaction component 14.

[0025] The sensor 16 also comprises communication means 19 for transmitting a clamping state between the clamping component 13 and the reaction component 14. The clamping state is determined from the force undergone by the pressure gauge. constraint 17 compressed between the two components 13 and 14 during tightening. If this force is greater than a threshold, then the clamping state between the components 13 and 14 is sufficient to guarantee a mechanical connection avoiding any vibration. On the other hand, if this force is lower than the threshold, then the state of tightening between the components 13 and 14 is insufficient to guarantee a mechanical connection avoiding any vibrations. The means of communication 19 are advantageously of the wireless type.

[0026] Advantageously, the sensor 16 is an autonomous sensor, that is to say a sensor which does not require any battery or on-board battery to ensure its operation.

For this purpose, the communication means 19 comprise a radio-frequency transponder 20 associated with an antenna 23 intended to receive electromagnetic waves to electrically supply the sensor 16 and to transmit a signal representative of the tightening state to destination of a reader 25. The electrical energy and therefore the current supplying the sensor 16 comes from a transformation by induction of an electromagnetic signal received by the antenna 23. The transponder 20 manages the transmissions and receptions of electromagnetic signals through antenna 23.

The clamping sensor 16 may also include a system 26 for collecting the electrical energy received by the antenna 23. The collection system 26 may include a capacitor circuit making it possible to temporarily store electrical energy to ensure a power supply for the various components of the sensor 16. An energy processing module 24 will be able to provide filtering of the electrical signals received as well as DC-DC conversion (or DC-DC conversion) so as to apply a suitable voltage to the electrical energy storage 26.

[0029] A microcontroller 22 manages the operation and communication between the various components of the tightening sensor 16. A module 28 provides the interface between the strain gauge(s) 17, 46 and the microcontroller 22. The module 28 makes it possible to feed and collect the data returned by the strain gauges 17, 46.

The sensor 16 is advantageously of the RFID type for "Radiofrequency Identification" in English. Alternatively, the transponder 20 may be of the NFC type for "Near Field Communication" in English, "Bluetooth" (registered trademark), BLE for "Bluetooth Low Energy", "Zigbee" (registered trademark) or LoRaWAN (for "Long Range Wide Area Network" in English) or any other type of radio frequency device suitable for the application.

Alternatively, the means of communication 19 may be wired type. It will thus be possible to use electrical harnesses ensuring an electrical connection between the microcontroller 22 of the sensor 16 and a central control system connected to a plurality of sensors 16. As a variant, the sensor 16 could comprise an on-board cell or battery.

[0032] In the example shown in Figure 1, the sensor 16 has the shape of a washer disposed between the clamping component 13 and the reaction component 14. Such a configuration of sensor 16 can easily be integrated on parts clamped by a screw-nut torque.

[0033] The sensor 16 includes a cover 27 that is transparent to radiofrequency waves. Antenna 23 may be wound inside the internal volume of cover 27. Furthermore, strain gauge 17 may be mounted on a mechanical part 29 working in compression. The mechanical part 29 is preferably made of a metallic material. The strain gauge 17 may comprise a piezoresistive material or any other material whose conductivity varies according to the stress undergone.

An implementation of the invention is described below with a piece of furniture 10 constituted by an airplane seat shown in FIG. 2. The airplane seat 10 comprises at least one seat 31 at least one folder 32. In this case, the seat 10 has two bases 31 and two folders 32 corresponding. The number of seats 31 and backrests 32 can of course be adapted according to the number of places desired on the seat 10. Liftable or fixed armrests 33 can be arranged on either side of a backrest 32. The armrests 33 are each mounted on a butt 35 integral with a lower structure 36 of the seat. The lower structure 36 carries bolts 38 each intended to be fixed on a fixing rail 39 mounted on a floor of the aircraft cabin.

For this purpose, a lock 38 comprises a body 40 and a plunger 41 movable in translation relative to the body 40. A tightening of a nut 42 of the lock 38 brings the plunger 41 closer to the body 40, so that the lock 38 is fixed on the fixing rail 39 by clamping a portion of said fixing rail 39 between the lips of the plunger 41 and the body 40 of the lock 38 .

The sensor 16 in the form of a washer can be arranged between the nut 42 constituting the clamping component 13 and the body 40 of the lock 38 constituting the reaction component 14. The sensor 16 in the form of a washer is arranged around the stem of the screw carrying the nut 42. The sensor 16 is intended to be compressed between the nut 42 and the body 40 during a tightening of the lock 38 on the rail 39.

Alternatively, the sensor 16 is disposed between the body 40 of the latch 38 constituting the clamping component 13 and the fixing rail 39 constituting the reaction component 14. In this case, the sensor 16 may take the form of a sheet pressed against a portion of the fixing rail 39. The sheet incorporates one or more strain gauges.

The control of the tightening of the locks 38 of seats is described below by interrogating the tightening sensors 16 via a radio-frequency reader 25. The radio-frequency reader 25 advantageously takes the form of an RFID type reader.

The reader 25 may be a mobile reader associated with a screen 44 of a portable electronic device, such as a mobile phone, digital tablet or laptop computer. As a variant, the reader 25 is an autonomous device integrating a screen 44 for displaying the tightening state of the various seat locks 38 .

The operator moves inside the aircraft cabin with the reader 25 which emits request signals. When the reader 25 is at a distance of less than a few meters from a tightening sensor 16, for example a distance of 2 to 3 meters, the electromagnetic signals of the reader 25 provide an inductive power supply to the tightening sensor 16.

The electrical energy received by the collection system 26 thus makes it possible to supply the microcontroller 22. The microcontroller 22 recovers the signals from measurement of the strain gauges and transmits them by radio frequency to the reader 25 via the antenna 23.

The screen 44 associated with the reader 25 makes it possible to display a report of the tightening state of the set of locks 38 of seats present in the cabin. If a tightening torque is below a predetermined threshold, for example set at 2N.m or at a percentage of the optimum torque, for example a percentage of the order of 80% of the optimum torque, a visual warning signal and/ or sound is emitted to the operator. The comparison between the measured tightening torque and the predetermined threshold can be performed at the level of the sensor 16 by the microcontroller 22 or by the reader 25 or by the portable device receiving the measurements of the tightening force.

As a variant, the aircraft cabin is equipped with one or more fixed radio-frequency readers 25 making it possible to supply the sensors 16 and to recover the data therefrom. The screen 44 can also take the form of a control station, consisting of a computer or a server, installed in an area of the aircraft cabin reserved for flight personnel.

The identification of a defective lock 38 is carried out by means of a database establishing a correspondence between the unique serial numbers of the sensors 16 and the unique references of locks and/or seats 10 with which have been associated the sensors 16. This database may be stored in a memory of the portable electronic device, of the reader, or of the control station. The database thus makes it possible to know the number of the seat of the sensor 16 interrogated and the position of the sensor 16 on the seat 10.

It should be noted that the tightening torque of the lock 38 is estimated using an extrapolation of measurements of the strain gauge 17. In order to determine a relationship between a deformation of the strain gauge 17 and a corresponding tightening torque , several attempts to tighten and loosen a lock 38 are carried out. The tightening torque can be measured with different types of sensors or tools, such as a dynamometer. The relationship is finally established using statistical "regression" techniques. A linear relationship links, theoretically, the two variables but non-linearity is possible due to geometry, friction, contact forces, and other mechanical phenomena occurring between the clamping component 13 and the clamping component. reaction 14. A linear regression of the type y=b0+b1 x or a polynomial regression y = ' _lk=Q b _k x ^k which can establish a correspondence between the two parameters is shown in figure 3.

[0047] Advantageously, an additional gauge 46 (cf. FIG. 2) is also provided for measuring the stresses exerted on the seat other than the stresses of tightening a lock 38. This makes it possible to prevent the stresses exerted on the seat affect the tightness measurement.

The additional gauge 46 is positioned in an area of the seat which is not subject to the stresses induced by the tightening and which makes it possible to detect any external stress also detected by the main gauge 17. The stresses measured by the additional gauge 46 can be for example the weight or the activity of a passenger on the seat. The strain gauge 46 could for example be installed on a seat butt 35 or another element of the seat structure.

The strain gauge 46 is therefore necessary in the case of the presence of an external load on the system at the time of the operator's inspection, or for a version of a system operating in real time.

[0050] A filtering of the data returned by the gauges 17 and 46 is carried out to dissociate the tightening stresses with respect to the stresses induced by another load exerted on the seat. The final calculation of the tightening torque is carried out at the level of the aircraft cabin control station by the autonomous analysis of the tightening data returned by the two gauges 17 and 46, then is transmitted by radiofrequency to the reader 25 of the 'operator. Alternatively, the calculation of the tightening torque is carried out directly by the reader 25 or the associated electronic device. Of course, the different characteristics, variants and/or embodiments of the present invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that a person skilled in the art may consider in the context of the present invention and in particular all combinations of the various modes of operation described previously, which may be taken separately or in combination.

Claims

Aircraft cabin furniture element (10) comprising:

- a clamping component (13) and a reaction component (14) intended to be clamped against each other to ensure fixing of said piece of furniture (10), characterized in that said piece of furniture (10) further comprises a clamping sensor (16) disposed between the clamping component (13) and the reaction component (14),

- said tightening sensor (16) comprising a strain gauge (17) intended to measure a tightening torque between the tightening component (13) and the reaction component (14), and

- communication means (19) for transmitting a tightening state between the tightening component (13) and the reaction component (14). Aircraft cabin furniture element according to claim 1, characterized in that the communication means (19) are of the wireless type. Aircraft cabin furniture element according to claim 2, characterized in that the tightening sensor (16) is an autonomous sensor. Aircraft cabin furniture element according to any one of Claims 1 to 3, characterized in that the communication means (19) comprise a radio-frequency transponder (20) associated with an antenna (23) intended to receive electromagnetic waves to electrically power the tightening sensor (16) and to transmit a signal representative of the tightening state. Aircraft cabin furniture element according to any one of Claims 1 to 4, characterized in that the sensor (16) has the shape of a washer. Aircraft cabin furniture element according to any one of Claims 1 to 5, characterized in that it consists of an aircraft seat (10) comprising a lock (38) intended to be fixed on a fixing rail (39) of the aircraft cabin. Aircraft cabin furniture element according to Claim 6, characterized in that the sensor (16) is arranged between a nut (42) constituting the tightening component (13) and a body (40) of the lock (38) constituting the reaction component (14). Aircraft cabin furniture element according to Claim 6, characterized in that the sensor (16) is arranged between a body (40) of the lock (38) constituting the clamping component (13) and the fixing rail (39 ) constituting the reaction component (14). Airplane cabin furniture element according to any one of Claims 6 to 8, characterized in that it further comprises an additional gauge (46) for measuring stresses exerted on the seat other than bolt tightening stresses (38). Aircraft cabin furniture element according to claim 9, characterized in that it comprises means for filtering data returned by the strain gauge (17) and the additional gauge (46) to dissociate tightening stresses with respect to to stresses induced by another load exerted on the seat.