Abstract:
A floor covering includes: a surface layer having a plurality of conductive segments capable of being supplied with electrical power; an at least partially electrically insulating intermediate layer having a plurality of through-recesses distributed in a substantially regular manner so that the mean distance between a recess and the recess closest thereto is between approximately 5 and 20 cm; a base layer having a plurality of electrical contacts, of which at least some correspond to the recesses of the surface layer and are connected to an electronic controller; the surface, intermediate and base layers being superimposed in this order and positioned so that at least some of the conductive segments are arranged at least partially opposite a recess of the intermediate layer, and so that these conductive segments react to a pressure by approaching the electrical contacts which correspond to the base layer.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to the field of floor coverings, and more specifically floor coverings which are capable of detecting that a person has fallen. 
     Description of the Related Art 
     All developed countries are experiencing an increased ageing of their populations. This ageing can be seen in a very sharp increase of the number of people aged 60 and over. This situation creates a real challenge in the field of public health. It also creates serious problems in the management of the dependency of elderly people. 
     This is because elderly people are seeing their life expectancy increase every year. Furthermore, the development of social structures results in these people leading a more and more solitary existence, or living within specialised structures. 
     For people living alone, this isolation is an acute problem since they are at risk of dying of the consequences of a fall owing to an inability to call for assistance. In the case of specialised structures, the detection of falls is also very important, if it is desirable to avoid a very high number of care staff, with a very high cost for providing care, and cases of litigation regarding responsibility for lack of supervision. 
     The increasing awareness of these problems has resulted in studies being carried out which have shown that more than 7500 people die each year in France as a result of a fall which has not been detected in time, or from the consequences of a fall which has not been dealt with in a timely manner. 
     Currently, there is no device which provides a truly satisfactory solution for the detection of persons falling within their everyday environment. 
     SUMMARY OF THE INVENTION 
     The invention is intended to improve the situation. 
     To this end, the invention proposes a floor covering which comprises:
         a surface layer which comprises a plurality of conductive segments which are capable of being supplied with electrical power,   an intermediate layer which is at least partially electrically insulating and which comprises a plurality of through-recesses which are distributed in a substantially regular manner so that the mean distance between a recess and the recess to which it is closest is between approximately 5 cm and 20 cm,   a base layer which comprises a plurality of electrical contacts, of which at least some correspond to the recesses of the surface layer and which are connected to an electronic controller,   the surface layer, the intermediate layer and the base layer being superimposed in this order and positioned so that at least some of the conductive segments are arranged at least partially opposite a recess of the intermediate layer, and so that these conductive segments react to a pressure by approaching corresponding electrical contacts of the base layer,       

     the electronic controller further being arranged to selectively transmit a warning signal, in accordance with a condition which comprises the number of conductive elements to which it is connected which are adjacent to a conductive segment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       Other features and advantages of the invention will be better appreciated from a reading of the following description, taken from examples which are given by way of non-limiting illustration and taken from the drawings, in which: 
         FIG. 1  is a view with the covering according to the invention being partially broken away, 
         FIG. 2  is a close-up view of a portion of  FIG. 1 , 
         FIG. 3  is a sectioned view of  FIG. 2 , 
         FIG. 4  is a view similar to the view of  FIG. 3  when the covering is subjected to pressure, and 
         FIG. 5  is an example of a flow chart of an operation implemented in the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following drawings and description contain, for the most part, elements of a specific nature. They will therefore be able not only to serve to provide better understanding of the invention, but also to contribute to the definition thereof, where applicable. 
     As can be seen in  FIG. 1 , a floor covering  2  comprises a surface layer  4 , an intermediate layer  6 , a base layer  8  and an electronic controller  10 . 
     In order to better show all these elements,  FIGS. 1 to 4  will be described below simultaneously. In  FIG. 1 , a portion of the surface layer  4  has been broken away in the top left corner of the covering  2 .  FIG. 2  is a close-up view of a portion framed by dotted lines in  FIG. 1 , whilst  FIGS. 3 and 4  are sectioned views of  FIG. 2 , in the rest state and in response to a pressure which has a vertical component. 
     The term floor covering is intended to be understood to refer to any type of floor covering. This may be a simple carpet, that is to say, a floor covering whose surface-area is between approximately 60 cm 2  and a few tens of m 2 . However, the term floor covering has a much wider meaning and may cover all of the floor of a building or a dwelling, at least in the portions thereof which are intended to be visited by elderly persons. As can be seen in  FIG. 1 , the surface layer  4  comprises an electrical conductor  12  which extends in several parallel lines over the entire height of the floor covering  2 . 
     In the example described here, the conductor  12  is a single electrical wire having a diameter of approximately 1 mm which is connected to an electrical power supply which is not illustrated. The wire  12  rests in the example described here on a lower portion of the surface layer  4 , which electrically insulates it. The wire  12  may or may not be further insulated by a sheath. The diameter of this electrical wire may vary in accordance with the current requirements and the supply options envisaged. This single electrical wire may be replaced by a plurality of wires which are electrically insulated from each other and which are each connected to an independent electrical supply. It may also be a conductor system, for example, of the monoconductor or multiconductor printed circuit type, or the like. It may also be a conductive layer which covers the lower portion of the surface layer  4 . It may also be a plurality of push-buttons. 
     As will be seen below, the conductor  12  performs the function of becoming deformed under pressure in a substantially vertical direction in order to establish a local electrical contact which allows this pressure to be detected. 
     The intermediate layer  6  is located directly below the surface layer  4 , in contact with the electrical conductor  12 . In the example described here, the intermediate layer  6  is produced from an electrically insulating material, for example, a layer of insulating plastics material. 
     The intermediate layer  6  comprises a multiplicity of holes  14  which allow the base layer  8  to appear in  FIGS. 1 and 2 . 
     The holes  14  are through-recesses which are formed in a regular manner in the intermediate layer  6 . In the example described here, these recesses have a circular shape with a radius of 1 cm. In other embodiments, the shape of these recesses may vary and may, for example, be a rectangle, a lozenge, or any other suitable polygon, or any closed contour, in particular formed by means of revolution. The recess has a surface which is selected to be between 2 cm 2  and 9 cm 2 , for a thickness of the intermediate layer of between approximately 3 mm and 12 mm. 
     Consequently, the recesses  14  are provided to allow the deformation of the layer  4  through them so that the conductor moves into the vicinity of and/or into contact with (adjacent to) the base layer  8 . The portion of the conductor  12  which moves into the vicinity of and/or into contact with the base layer  8  forms a conductor segment. 
     As can be seen in  FIGS. 3 and 4 , the base layer  8  has a plurality of electrical contacts  16  which are each connected by means of a wire  18  to the electronic controller  10 . 
     In the example described here, the electrical contacts  16  of the base layer  8  are selected to have a contact surface 3 to 5 times greater than the contact surface of an electrical conductor  12  of the surface layer  4 . This facilitates the contact therewith during a deformation of the surface layer  4  following a pressure, and prevents detection errors. However, in different variants, the cross-section of the electrical contact  16  may be able to be selected to be identical to that of the electrical conductor  12 , or less than it. 
     In the example described here, the surface layer  4  is superimposed on the intermediate layer  6 , which is itself superimposed on the base layer  8 , in this order. 
     The coating  2  is therefore provided to be deposited with the base layer  8  in contact with the ground and with the surface layer  4  as a contact surface for walking. To this end, the surface layer  4  may advantageously be of linoleum, a plastics tile, a carpet or any other type of floor surface as defined by sanitary standards. 
     Advantageously, the surface layer  4  may be selected to be less hard than the intermediate layer  6 , which may, for example, have a pressure resistance of approximately from 15 kg/cm 2  to 25 kg/cm 2 . In this manner, the surface layer  4  may become deformed more readily inside the recesses  14  under the effect of pressure, which allows the detection sensitivity to be increased. 
     In the same manner, the base layer  8  is suitable for acting as a connection to the ground, and to be, for example, of rubber if the covering  2  is a carpet, or to be a material which is suitable for adhesion or another fixing method if it is a covering for an entire room. 
     Besides being superimposed, the layers  4 ,  6  and  8  are specifically arranged so that the conductor  12  is arranged opposite all the recesses  14  or at least the vast majority thereof, and so that the electrical contacts  16  are themselves opposite all these recesses  14  or the vast majority thereof. 
     In this manner, as illustrated in  FIG. 4 , when a pressure represented by an arrow in this Figure, for example, the force applied by the weight of a person, is applied to the surface layer  4 , it becomes deformed and fills the recesses in the region of the location where this pressure is applied, and the conductor  12  comes into contact with the electrical contacts  16  in the relevant recesses  14 . 
     In the example described here, the recesses  14  are spaced apart vertically and horizontally, from centre to centre, by a distance of approximately 7.5 cm and if a covering having a surface of 1.6 m by 2.1 m is considered, 252 detection locations are therefore obtained, which are formed by the three members comprising the conductor  12 , recess  14 , contact  16 . Advantageously, the spacing between the recesses  14  may be between 5 cm and 20 cm. 
     When a person falls, he is necessarily in an extended position on his back, on the stomach, or at least with a quite extensive portion of his body on the ground. As each of these detection locations is connected to the electronic controller  10  by a wire  18 , it becomes easy to monitor the activity in order to detect any fall. A sufficiently tight mesh thus allows the difference to be detected between a fall and the presence of one or more persons walking on the covering  2 . 
     Furthermore, the mesh of the example described here is also very tight, which provides a high level of precision. 
     The extent of a person lying down signifies that it is possible to detect a fall:
         when more than ten detection locations are activated in a square having a side of approximately 30 cm, or in a rectangle which has a similar surface-area and whose diagonal line is approximately 35 cm long, or over a surface-area of approximately 0.09 m 2 , for a minimum length of time, for example, in the order of one minute, or   when 4 detection locations which are aligned horizontally, diagonally or vertically are activated for a minimum period of time, for example, in the order of one minute.       

     Generally, the minimum period of time for the detection may be selected to be greater than 15 seconds. In a variant, the detection may not be dependent on a minimum period of time. 
     These scenarios exclude the case of walking or the presence of several people on the coating  2 . This is because an adult foot in the vast majority of cases has a length of less than 35 cm, which corresponds to a shoe size  53 . Consequently, the detection criteria described above allow the upright position to be discriminated, in which only the feet are in contact with the ground. Furthermore, when several people are present, even if they are very close, they will not bring about any detection owing to the meshes described, even if the centre-to-centre distance of the recesses  14  is 20 cm. 
     The calculations required for the detection may be carried out within the electronic controller  10 . To this end, it may comprise a calculation unit in the form of an on-board device, a dedicated card or any other appropriate means. The electronic controller  10  may also comprise wired communication means (via conventional telephone line or via a network, for example, Ethernet), or wireless communication means (via a GSM, GPRS, 3G or WiFi communication interface). 
     Furthermore, the electronic controller  10  may be produced in several portions. In this instance, the electronic controller  10  comprises a first portion  20  which is connected to the wires  18 , and which comprises a communication interface which is similar to that described above. 
     The portion  20  communicates with a remote portion  22  which can carry out the detection calculations mentioned above, and which may itself comprise a communication interface similar to the one described above. 
     These communication interfaces may be used in order to transmit alerts in the event of a fall being detected, for example, to a central telesurveillance station, to an assistance call centre, to the nursing station in the case of a hospital, a clinic or a retirement home, etcetera. 
     Finally, the electronic controller  10  may include only a communication interface which is similar to the one described above, all of the calculations for the detection of a fall being remote on a detection server to which the electronic controller  10  is connected via this interface. 
       FIG. 5  shows an example of a flow chart that the electronic controller  10  can carry out in order to detect falls. 
     In an operation  20 , the electronic controller  10  is initialised, with all the parameters connected with the detection of falls, and with the initialisation of the communication interface. 
     Then, in an operation  25 , a detection loop begins. This loop comprises the detection of the electrical signals in the wires  18 . When no pressure is detected, the wires  18  do not have any electrical signal. 
     If an electrical signal is detected in a specific wire  18 , this means that the conductor  12  is in contact with an electrical contact  16 . In response to this detection, an identifier of the detection location associated with the given wire  18  is stored, with a time marker. 
     Then, in an operation  30 , the calculation unit verifies the list of identifying pairs of the wire/time marker in order to determine whether these verify one of the conditions for the detection of a fall set out above. 
     If this is the case, the communication interface is activated in an operation  35  in order to send a fall detection signal, then the detection continues with the operation  25 . If not, the loop continues directly with the operation  25 . 
     The sending of the fall detection signal may comprise all the useful information, including the location of the covering  2  if it is known, a time period associated with the time markers in order to indicate the time of the fall, etcetera. 
     As mentioned above, the invention may be applied both to carpets and complete floor coverings, in order to equip an entire hospital or a retirement home, for example, and is based on the conversion of a pressure connected with a fall into an electrical signal whose location is known, in order to detect a fall. 
     In a different number of variants, the covering may have the following features:
         the electronic controller comprises a calculation unit which is capable of detecting a fall in accordance with the signal transmitted over the electrical wires which are connected to the electrical contacts,   the calculation unit is arranged so as to detect:
           the activation of more than ten detection locations in a surface-area of approximately 0.09 m 2 , for a period of time greater than or equal to 30 seconds, and/or   the activation of four detection locations which are aligned horizontally, diagonally or vertically for a period of time greater than or equal to 30 seconds,   
           the electronic controller further comprises a communication interface which is capable of selectively transmitting the detection signal,   the communication interface is of the wired type,   the communication interface operates with a conventional telephone network,   the communication interface operates with an Ethernet network,   the communication interface is of the wireless type,   the communication interface operates with a wireless telephone network of the type GMS, GPRS or 3G, and   the communication interface operates with a wireless network of the WiFi type.