Field of the invention

The present invention pertains to a heated floor panel, par ^¬ ticularly in the floor near the exit or entrance of an air- craft. Moreover, the invention pertains to an aircraft having a heated floor panel, in particular in the floor near the exit or entrance.

Background of the invention

In the exit areas of aircraft heated floor panels may be em ^¬ ployed. The floor panels are equipped with a heating system internal to the floor panel which is able to heat up the floor near the exit of the aircraft. This may done on the one hand to improve the comfort level of the passengers and the cabin crew, on the other hand to compensate for the usually low temperatures on the outside of the aircraft that may oc ^¬ cur especially during long-haul flights. The document US 6,611,659 B2 discloses a heated floor panel for an aircraft that comprises a heater, a temperature sensor and an overheating protection switch to keep the floor panel from overheating. The document US 2011/0149447 Al discloses a heatable floor panel having a ground fault interrupting circuit installed therein . The document EP 1 854 719 A2 discloses a heated floor panel for an aircraft having a heated panel, a controller strapped to the outside of the housing of the floor panel and a ground fault circuit interrupting the current delivered to the heat ^¬ ed panel in case of a ground fault.

The document US 7,104,462 B2 discloses a solid state thermo ^¬ stat including a thermostat input operatively configured to be coupled to a temperature sensor, a comparator for comparing an output of the temperature sensor to a predefined set- point temperature, and solid-state switching circuitry opera ^¬ tively coupled to the comparator for selectively switching current to a thermostat output based on the comparison by the comparator.

Summary of the invention

It is therefore one object of the present invention to pro- vide for an improved heated floor panel which is easy to maintain and repair, easy to install, reliable in terms of electric fault detection and flexible in linking to existing floor heating systems of an airborne vehicle, such as an air ^¬ craft .

This problem is solved by a floor panel for an aircraft hav ^¬ ing the technical features of claim 1, and an airborne vehi ^¬ cle having the technical features of claim 13. According to a first aspect of the present invention, the floor panel comprises a heated floor panel for an airborne vehicle. The floor panel comprises a controller housing, a first heated panel configured to heat the floor panel, a pan ^¬ el connector arranged in a wall of the controller housing, at least one power line coupled between the panel connector and the heated panel and configured to supply electric power, which is input to the panel connector, to the first heated panel, a switch connected in one of the power lines, and a microcontroller connected to the switch and configured to ac ^¬ tuate the switch for interrupting the electric power supply to the first heated panel in case of an electric fault in the floor panel.

According to a second aspect of the present invention, an airborne vehicle comprises a floor heating system, the floor heating system comprising a floor panel according to the first aspect of the present invention, which is operatively connected to a cabin information data system of the airborne vehicle via a communication data bus.

Embodiments of the invention

One main idea of the present invention is to provide for a heated floor panel for an airborne vehicle, which may be eas ^¬ ily installed within the vehicle, which is easy to maintain and repair and which provides an integral housing for compo- nents, in particular for a microcontroller of the floor panel which may be arranged within the floor panel. That way, a separate housing structure for the microcontroller in the airborne vehicle or the structure of the vehicle may be dis ^¬ pensed with. With such a floor panel, the installation ef- fort, installation space and installation costs may be sig ^¬ nificantly reduced.

The dependent claims provide additional technical features of advantageous embodiments and further improvements of the in- vention.

According to an embodiment, the floor panel further comprises a second heated panel configured to heat the floor panel, wherein the microcontroller is configured to control a power supply to the first and the second heated panel. This pro ^¬ vides the advantage of multiple heated panels being control ^¬ lable by a single microcontroller in a master/slave relation- ship. This allows for a more flexible layout of the floor panel as well as easier industrialization, cost reduction and other advantages. According to a further embodiment of the floor panel, the floor panel further comprises a temperature sensor arranged in the heated panel and coupled to the microcontroller. Ad ^¬ vantageously, with such a temperature sensor it is possible to control the actual average temperature that the floor pan- el is heated up to.

According to yet another embodiment of the floor panel, the microcontroller is configured to store a configurable temper ^¬ ature setpoint value and to control the heated panel accord- ing to the temperature setpoint value and a temperature value determined from the temperature sensor. This provides the ad ^¬ vantage that the temperature can be flexibly set via external access to the floor panel. In some embodiments, a value for the temperature setpoint may be adjusted externally and transmitted via a data bus to the microcontroller.

According to yet another embodiment of the floor panel, the controller housing is connected to the heated panel by means of an electrical connector, which is electrically engaged, when the controller housing is mechanically mounted to the heated panel. Advantageously, the electrical connector may be electrically engage without a specific need for visual con ^¬ trol or feedback providing a secure and reliable electrical connection of the controller housing with the heated panel.

According to yet another embodiment of the floor panel, the floor panel further comprises a data line coupling the micro ^¬ controller to the panel connector configured to transfer controller data between the microcontroller and the panel con- nector. Advantageously, the data line being integrated into the panel connector reduces the number of connections between the floor panel and other components of an airborne vehicle. Moreover, the installation effort is significantly reduced. Additionally, the data line may be used for transferring the temperature setpoint value for controlling the temperature of the heated panel to the microcontroller.

According to yet another embodiment of the floor panel, the floor panel further comprises a communication device coupled to the microcontroller and configured to provide wireless communication to and from the microcontroller. With such a wireless communication, the number of electric lines needed to connect the floor panel to other components of the air ^¬ borne vehicle and therefore the system weight of the airborne vehicle is advantageously reduced. According to yet another embodiment of the floor panel, the switch comprises a solid state relay, in particular a MOSFET semiconductor switch. MOSFET switches are particularly advantageous since the MOSFET switch can be actuated at any point in time and not just only at zero current condition on the power lines. Thus, the floor panel is more effectively pro ^¬ tected against electric faults.

According to yet another embodiment of the floor panel, the floor panel further comprises a ground fault detection unit coupled to the at least one power line and configured to de ^¬ tect a ground fault of the floor panel. According to another embodiment of the floor panel, the floor panel further com ^¬ prises an arc fault detection unit coupled to the at least one power line and configured to detect an arc fault in the floor panel. In both cases, the floor panel is effectively protected against electric fault conditions. This leads to a better protection against electric hazards like fire, smoke, overheating or malfunction. According to yet another embodiment of the floor panel, the microcontroller is further configured to monitor the current in the heated panel, and/or to monitor the functional state of the switch, and/or to monitor the temperature in the controller housing, and/or to monitor the functional state of the temperature sensor. With these measures, an effective self-diagnosis functionality of the floor panel may be imple- mented.

According to yet another embodiment of the floor panel, the microcontroller is further configured to store a protocol as ^¬ sociated with electric faults detected by the ground fault detection unit and/or the arc fault detection unit in a nonvolatile data storage. In order to reliably be able to track back error conditions the occurrence of electric faults may be stored until a maintenance and repair technician is able to assess and evaluate the severity and the nature of the fault.

According to yet another embodiment of the floor panel, the floor panel may further comprise a reset button configured to reset all or a subset of fault entries stored in the protocol in the non-volatile data storage.

According to yet another embodiment of the floor panel, all or a subset of fault entries stored in the non-volatile data storage may be resettable by external means using either the data line or the communication device.

The invention will be explained in greater detail with reference to exemplary embodiments depicted in the drawings as ap ^¬ pended .

Short summary of the drawings

The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and to ^¬ gether with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The ele ^¬ ments of the drawings are not necessarily to scale relative to each other. Like reference numerals designate correspond ^¬ ing similar parts.

Fig. 1 shows a floor panel for an aircraft according to an embodiment of the invention.

Fig. 2 shows a floor panel for an aircraft according to another embodiment of the invention.

Fig. 3 shows a floor heating system of an aircraft including one or more heated floor panels accord ^¬ ing to yet another embodiment of the invention.

Fig. 4 shows an airborne vehicle including a floor

heating system according to yet another embodiment of the invention.

Fig. 5 shows an arrangement of heated floor panels in a master/slave architecture according to yet an ^¬ other embodiment of the invention.

Detailed description of the embodiments

Although specific embodiments have been illustrated and de ^¬ scribed herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equiva ^¬ lent implementations may be substituted for the specific em ^¬ bodiments shown and described without departing from the scope of the present invention. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein. „

Fig. 1 shows a floor panel 10, particularly a heated floor panel 10 for use in an airborne vehicle such as an aircraft. The floor panel 10 may be used in the floor near an exit or entrance area, for example a door of an airborne vehicle. Fig. 4 exemplarily shows such an airborne vehicle 20 having a floor heating system 21.

Returning to Fig. 1, the heated floor panel 10 may comprise a controller housing 9. The controller housing 9 may for exam- pie comprise a metallic material such as aluminum or a syn ^¬ thetic material.

The floor panel 10 may further comprise a heated panel 6 which is configured to heat the floor panel 10. The heated panel 6 may for example comprise an electric heating wire 6a or an electric heating foil 6a as a heater element, for exam ^¬ ple comprising manganin(R), which may be connected to power lines lib, 11c which carry a supply current for the heating wire 6a. It may also be possible to use heating foils instead of or additionally to the heating wire 6a. The panel sheets 6b may provide heat spreading functionality as well as me ^¬ chanical protection for the floor panel 10. The panel sheets 6b may for example comprise glassfibre structures, honeycomb structures, metallic surfaces or the like. The heated panel 6 provides first of all a mechanical function as it has to withstand the mechanical loads introduced to the heated panel 6 by the occupants of the aircraft and the aircraft itself. Proper selection of the panel sheets 6b may ensure this me ^¬ chanical function besides the purpose of supporting the heat spreading .

The floor panel 10 may further comprise a panel connector 11 which may be arranged in a wall of the controller housing 9. The panel connector 11 may be configured to couple the floor panel 10 to a power supply system within the airborne vehicle 20. The panel connector 11 is adapted to facilitate the in ^¬ stallation of the floor panel 10 in the airborne vehicle 20 by reducing the number of separate lines to be led through the airborne vehicle 20 and the respective connections to be made. The power supply may for example be a 115VAC power sup ^¬ ply.

The power lines 11a, lib are coupled between the panel con ^¬ nector 11 and the heated panel 6 and configured to supply electric power, which is input to the panel connector 11, to the heated panel 6 via a plug-in unit. In at least one of the power lines a switch 3 is connected. The switch 3 may for ex ^¬ ample comprise a solid state relay, in particular a MOSFET semiconductor switch. The switch 3 may be actuated to interrupt the electric power supply to the heated panel 6. The components 1, 3, 4 and 5 comprised in the controller housing 9 may constitute an integral subassembly within the housing. An electrical connector may be provided as heater connector 7 to electrically engage the controller housing 9 with respective electrical lines in the heated panel 6, or mounted on the heated panel 6.

The microcontroller 1 may be connected to the switch 3 in order to actuate the switch 3 for interrupting the electric power supply to the heated panel 6 in case of an electric fault in the floor panel 10. For detection of such electric faults, the floor panel 10 may for example comprise a ground fault detection unit 4 coupled to the at least one power line lib, 11c which may be configured to detect a ground fault of the floor panel 10. For example, undesired leakage currents may occur between electrical components of the heated panel 6 and the aircraft structure to which the heated panel 6 may be fixed. Such leakage currents may be detected by the ground fault detection unit 4 as difference between the currents carried on the power lines lib, 11c. A ground fault may be detected when the sum of the currents flowing in lines lib and 11c is not zero, i.e. some current is flowing not on its dedicated path back to the electrical power supply. Apart from supplying the heated panel 6 with power, the power lines lib, 11c may also supply the electronic components in the controller housing 9, such as the microcontroller 1, with electric power.

Alternatively or additionally, the floor panel 10 may com ^¬ prise an arc fault detection unit 5 coupled to the at least one power line lib, 11c which may be configured to detect an arc fault in the floor panel 10. Both types of faults, ground faults and arc faults may endanger the safety of the floor panel 10, thus with the electric fault detections units 4 and/or 5 such electric faults may be detected early. Respec ^¬ tive countermeasures may be implemented by the microcontrol- ler 1. For example, in case of an electric fault, the power to the heated panel 6 may be shut down temporarily or contin ^¬ uously .

The microcontroller 1 may further be configured to store a protocol associated with electric faults detected by the ground fault detection unit 4 and/or the arc fault detection unit 5 in a non-volatile data storage. The data storage may be an internal memory of the microcontroller 1. The floor panel 10 may further comprise a reset functionality for the faults having been put into the protocol. For example, it may be possible to implement a reset button in the floor panel 10 by means of which a maintenance technician may be able to re ^¬ set the data storage and remove older fault entries in the protocol. Alternatively, it may be possible to erase older entries in the protocol by means of an on-board maintenance system of the airborne vehicle 20.

The floor panel 10 may further comprise a temperature sensor 2 arranged in the heated panel 6. The temperature sensor 2 may be coupled to the microcontroller 1. The microcontroller 1 may be configured to store a configurable temperature set- point value and to control the heated panel 6 according to the temperature setpoint value and a temperature value deter ^¬ mined from the temperature sensor 2. A value for the tempera ^¬ ture setpoint may be adjusted externally and transmitted via the data line 11a to the microcontroller 1.

In order to communicate with a floor heating system 21 of the airborne vehicle 20, the floor panel 10 may comprise a data line 11a coupling the microcontroller 1 to the panel connect ^¬ or 11 which may be configured to transfer controller data be- tween the microcontroller 1 and the panel connector 11, and, hence, the floor heating system 21. The data line 11a may be integrated into the panel connector 11 so that only a single data bus for power supply and data connection is necessary to couple the floor panel 10 to the floor heating system 21 and the power supply of the airborne vehicle 20. The data line

11a may for example be adapted to be coupled to a CAN bus of the floor heating system 21.

The microcontroller 1 may further be configured to monitor the current in the heated panel 6, the functional state of the switch 3, the temperature in the controller housing 9, and the functional state of the temperature sensor 2.

It may be possible to provide for multiple plug-in units in the controller housing 9 in order to distribute electric power from a single controller housing 9 to one or more heated panels 6. In that case, the microcontroller 1 may act as a master device for multiple heated panels 6 acting as respec ^¬ tive slave devices. The heated panels 6 may be connected to the controller housing 9 by means of an electric harness.

In order to connect multiple heated panels 6 to a single con ^¬ troller housing 9 it may be possible to provide further elec ^¬ trical connectors in the controller housing 9 which are not explicitly shown in Fig. 1 or 2.

Fig. 5 shows an example of such a master/slave architecture. Two heated panels 6 are connected to a single controller housing 9, whereas the leftmost heated panel 6 acts as the master panel and the rightmost heated panel 6 acts as a slave panel .

The microcontroller 1 may have additional control outputs for each of the slave devices. For example, the microcontroller 1 may control each heated panel 6 individually in parallel con ^¬ trol loops. All control loops may use the same reference tem- perature setpoint. Alternatively, it may be possible to se ^¬ lect a main heated panel 6 among the slave devices which is controlled in a single control loop by the microcontroller 1. In such a case, the remaining heated panels 6 are electrical ^¬ ly connected to the main heated panel in parallel so that the microcontroller 1 controls the temperature of the main heated panel and, in turn, the temperature of the remaining heated panels depending on the main heated panel.

Fig. 2 shows a schematic illustration of a floor panel 10 ac- cording to another embodiment. The floor panel 10 of Fig. 2 differs from the one depicted in Fig. 1 in that a communica ^¬ tion device 8 is coupled to the microcontroller 1 and configured to provide wireless communication 8a to and from the mi ^¬ crocontroller 1. With such a communication device 8 is it possible to dispense with the wire-bound data line 11a and couple to the floor panel to the floor heating system by means of a wireless connection 8a.

It may alternatively be possible to route controller data as power line communication (PLC) data over the power lines lib, 11c.

Both floor panels 10 of Fig. 1 and 2 may be configured to be coupled to a floor heating system 21 of an airborne vehicle 20 as exemplarily schematically illustrated in Fig. 3. One or several of the floor panels 10 may be coupled via a common data bus 12 with respect to the data lines 11a. One or both of the power lines lib, 11c may in each case be connected to a common power supply 13 of the airborne vehicle. It may be possible to provide electric ground by connecting one of the power lines lib, 11c to the structure of the airborne vehicle 20. The floor heating system 21 may for example comprise a cabin information data system (CIDS) 14 which may be coupled to one or more flight attendant panels (FAP) 15 by means of which communication or controlling data may be gathered from or input to the microcontrollers 1 of the respective floor panels 10. For example, the setpoint of the temperature to be achieved by the floor panels 10 may be set via a FAP 15. The microcontroller 1 may provide the CIDS 14 via the data bus 12 with diagnosis, repair and/or maintenance information. The microcontroller 1 may contain a built-in test equipment

(BITE) that may be controlled via the CIDS 14.

Using the floor panels 10 of Fig. 2, the floor panels 10 may in each case communicate with the CIDS 14 via a wireless com ^¬ munication link 8a as established by the communication device 8.

In the foregoing detailed description, various features are grouped together in one or more examples or examples with the purpose of streamlining the disclosure. It is to be under- stood that the above description is intended to be illustra ^¬ tive, and not restrictive. It is intended to cover all alter ^¬ natives, modifications and equivalents. Many other examples will be apparent to one skilled in the art upon reviewing the above specification.

The embodiments were chosen and described in order to best explain the principles of the invention and its practical ap ^¬ plications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with vari- ous modifications as are suited to the particular use contem ^¬ plated. In the appended claims and throughout the specifica ^¬ tion, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "compris ^¬ ing" and "wherein," respectively.

List of Reference Signs Microcontroller

Temperature sensor

Switch

Ground fault detection unit

Arc fault detection unit

Heated panel

a Heating element

b Panel sheets

Heater connector

Communication device

a Wireless communication

Controller housing

0 Floor panel

1 Panel connector

1a Data line

ib Power line

1c Power line

2 Data bus

3 Power supply

4 Cabin information data system

5 Flight attendant panel

0 Airborne vehicle

1 Floor heating system