EP1730480A1

EP1730480A1 - Impedemeter person-weighing scale

Info

Publication number: EP1730480A1
Application number: EP05746628A
Authority: EP
Inventors: Benoît LINGLIN; Bénédicte SIMOND
Original assignee: SEB SA
Current assignee: SEB SA
Priority date: 2004-04-01
Filing date: 2005-03-31
Publication date: 2006-12-13
Also published as: FR2868534B1; FR2868534A1; WO2005098376A1

Abstract

The inventive impedometer person-weighing scale comprises a measuring plate (1) supported by a weighing base provided with at least weight sensor, wherein said measuring plate is provided with at least two electrodes (2, 3, 4, 5) which contact a person's feet during measuring and are connected to an electric circuit for bioelectric impedance measuring and for displaying the person's body composition. According to said invention, said electrodes (2, 3, 4, 5) are made of an electroconductive tissue.

Description

IMPEDANCEMETER SCALE

The present invention relates to an apparatus for measuring body composition, in particular of the scale type comprising an electrical measurement circuit associated with a unit for calculating the bioelectric impedance of a person.

Measuring body composition gives indications of a person's state of health. More particularly, knowing the amount of body fat and its evolution over time is an effective aid during a diet. Among the methods of measuring fat mass, there is the measurement of the impedance of the human body correlated with the amount of water in the body: the human body is composed of lean mass, consisting of muscles, bones, organs, tissues and fat mass. Water constitutes about 70% of the lean mass, while the fatty mass contains almost none. Therefore, by measuring the electrical impedance of the human body and the total weight of a person, one can calculate, with a few adjustment parameters, the body fat and lean mass.

Such a device for measuring body composition is described in document FR 2 830 740 in the name of the applicant. This device comprises a measurement platform supported by weight sensors connected to a common electrical circuit and to a display. The circuit also includes an electronic module intended to measure a bioelectric impedance, as well as a source of electrical energy intended to generate a variable electrical signal which crosses the body of the individual. The signal is sent through the body of the individual by two excitation electrodes and the resulting signal is measured across two measurement electrodes. The electrodes are made of steel and are carried by a measuring plate made of plastic. When taking a measurement, the user stands on the measurement platform, his bare feet resting on the electrodes. Operating satisfactorily, this device offers little comfort in use, a feeling of cold is often felt in contact with the user's feet with the large metallic masses of the electrodes.

Document EP 1 125 550 describes another type of device for measuring body composition where the electrodes are produced by a conductive deposit in a thin layer on a flat plate made of glass or resin. This device certainly provides better comfort in contact with the feet with the electrodes than the device described above, but it turns out to be a delicate and fairly expensive embodiment.

The object of the present invention is to remedy at least in part the aforementioned drawbacks and to propose an apparatus for measuring body composition capable of avoiding the feeling of cold when in contact with the electrodes, while being reliable in operation and easy to produce.

Another object of the invention is an apparatus for measuring body composition which is able to offer good comfort in contact with the electrodes, while making it possible to produce advantageous designs of the latter and of the measuring plate supporting them.

Another object of the invention is a device for measuring the body composition of simplified construction, capable of being industrialized at a reduced manufacturing cost.

These aims are achieved with an impedance scale comprising a measuring plate supported by a weighing base which comprises at least one weight sensor, the measuring plate being provided with at least two electrodes intended for contacting the feet of the individual during a measurement, said electrodes being connected to an electrical circuit for measuring the bioelectric impedance and for displaying the body composition of the individual, because said electrodes are made of an electrically conductive fabric.

By electrically conductive fabric is understood a surface having a certain flexibility, while being resistant, constituted by a regular assembly of interlaced wires either woven or meshed, these wires being at least partly made of, or covered by, an electrically conductive material. Thus, the threads constituting the fabric can be electrically insulating fibers, synthetic or natural, woven or knitted, the fabric obtained then being metallized; or the fabric can be obtained by mixing electrically insulating fibers with electrically conductive threads; or even the threads constituting the fabric can be electrically conductive threads woven or knitted.

Furthermore, to perform its functions of excitation and measurement electrode in an impedance scale, the conductive surface of such an electrode intended for direct contact with the human body, in this case with the feet of a individual, must be at least equal to 1cm ² , distributed over an area of about 15cm ² to guarantee contact even in the event of improper placement of the foot on the platform of the device.

Such a fabric attached to the measuring plate of the device makes it possible to associate the properties of flexibility and mechanical resistance of the fabric with those of conductivity of the metallic deposit or of the electrically conductive wires which make up the fabric. This ensures the function of sending, respectively receiving, an electrical signal, by the tissue forming an electrode of the device. Furthermore, this fabric could be applied to a convex or concave surface or to a complex relief, the fabric being able to flex without stretching by adapting to the curve of such a non-planar surface.

In addition, the use of a conductive fabric ensures a feeling of increased comfort in contact with the user's feet with the electrodes of the measuring plate of the device, thus avoiding the feeling of cold generated by contact with masses. metal.

Preferably, the resistivity of such an electrically conductive fabric is less than 1000 Ohms / square. Such a fabric ensures sufficient electrical conductivity, without introducing measurement errors due to the resistance of the electrodes when they are used as excitation and / or measurement electrodes in a bathroom scale with impedancemetry.

In an alternative embodiment of the invention, said electrically conductive fabric is a metallized fabric.

Such a fabric is produced by applying a very thin layer of metal, for example nickel and / or copper, to a fabric, for example a polyester fabric. Such a fabric can be dyed or coated and it can also be washed and cleaned. This makes it possible to obtain a wide variety of colors and textures for the electrodes in order to be able to match them with those of the measuring plate and to obtain desired aesthetic effects.

In another advantageous variant of the invention, said electrically conductive fabric is a metallic fabric.

It turned out that the contact resistivity of the soles of the feet on a smooth plate is higher than that of the skin contact on a metallic fabric. This would be more particularly due to the fact that the frame or structure of such a fabric has more points of contact with the relief of the soles of the feet than a relatively flat plate.

Such a metallic fabric, made from woven, braided or meshed metallic wires, provides excellent conductivity, as well as good flexibility and remarkable longevity. Such a fabric can easily be cleaned by suction. In a preferred embodiment, this metallic fabric is of the three-dimensional type with multiple walls, for example of the type used in the electromagnetic shielding (EMI) of electronic devices, such a fabric ensuring at the same time excellent conductivity and a pleasant feeling of comfort to the touch. . In another variant of the invention, said electrically conductive fabric is a fabric made from wires comprising a core made of an electrically insulating material covered with a metallic coating.

This fabric made from woven, braided or meshed yarns then combines the good conductivity of the metallic coating with the excellent flexibility of a plastic core, while having good wear resistance.

Advantageously, said conductive fabric comprises woven, braided or meshed wires, of diameter less than 2 mm.

Such a conductive fabric is then flexible enough to adapt to a left surface or deformable under the effect of the weight of the user of the support piece of the electrodes.

In another variant of the invention, said electrically conductive fabric is a fabric made from son of electrically insulating material and incorporating at least one metallic conductor.

Such a fabric can be produced by wires of an electrically insulating material interlaced with metallic wires. In another embodiment, the fabric produced on the basis of electrically insulating son comprises an attached metallic or conductive wire, for example sewn, on this electrically insulating textile base. A flexible electrical circuit can thus be obtained on a textile basis.

In an advantageous embodiment, all the electrodes and their connections to a central electronic unit of an impedance scale are made by sewing the metal wires on a base formed by an electrically insulating fabric. Such a fabric can then be applied to the weighing pan.

Advantageously, said electrically conductive fabric is applied to a flexible support.

Such a flexible support generally has the shape of the electrode which is adapted to the shape of the foot of the individual who is standing on the platform of the apparatus and whose body composition is to be determined. Such an electrode on a flexible support forms a flexible sole assembly, having a significantly improved comfort in contact with the foot of the user. In addition, this flexible support increases the contact surface with the soles of the feet and therefore decreases the overall resistivity of this contact.

Usefully, said electrically conductive fabric is applied by gluing to its support.

This ensures rapid fixing of the conductive fabric of the invention on practically any type of support.

Preferably, the upper face of said measurement plate supporting the electrodes is a non-planar surface.

Such a curved surface adapts better to the shape of the soles of the feet of the user, the electrodes made of conductive fabric of the invention being flexible enough to match the shape of such a surface.

Advantageously, said fabric is covered with a layer of electrically conductive varnish on its face intended for contact with the feet of the user.

Such a conductive varnish provides protection against dirt and abrasion of the conductive fabric without altering its conductivity.

In an alternative embodiment of the invention, said electrodes are mounted removable relative to the measurement plate. The electrodes can be removably mounted with their support (for example a faceplate mounted on the front of the weighing pan) or with respect to their support, for example by using a hook attachment fitting into slots in a frame provided for this purpose. effect. This allows you to adapt the front of the scale to the colors of the bathroom or to replace stained or worn electrodes.

The invention will be better understood from the study of the embodiments taken on a non-limiting basis and illustrated in the appended figures in which: - Figure 1 is a perspective view of the apparatus of the invention;

- Figure 2 is an exploded view of the apparatus of the invention;

- Figure 3a is a front view of an electrode assembly according to an alternative embodiment of the invention and Figure 3b is a perspective view of the electrode assembly of Figure 3a; - Figure 4 is a perspective view of an apparatus of the invention with the electrodes of Figures 3a and 3b.

FIG. 1 illustrates a perspective view of an impedance scale according to the present invention comprising, in the upper part, a plate 1 provided with excitation electrodes 2.3 and measurement electrodes 4.5, as well as a display window 6. Several buttons 7 are arranged next to the display window 6 and are used to navigate the menu proposed on the display screen, in particular for entering the age value , the type of sex, the size, etc., to validate the values entered, to call up a memory, or even to display on the screen a specific type of measured parameter, its history, etc. The tray 1 is closed by lower part by a base 8 through which pass feet 9 bearing on the ground.

Referring to Figure 2, there is the base 8 of generally rectangular shape having holes 11 at the four corners. Feet 9 pass through the orifices 11 while bearing with their upper part on a support plate 12, their lower part being intended to bear on the ground. Each leg 9 contains a weight sensor of the type described in the document FR 2,734,050 in the name of the applicant, the foot 9 comprising an interface 10 fixed, for example, by gluing to the support plate 12, one of the bearing areas of the weight sensor being fixed by clipping to the interface 10 , the other support area coming into contact with the lower part of the foot 9. The contour of the support plate 12 follows that of the base 8, the support plate 12 being rigid enough to support without deforming the weight of the user . Such a support plate is made of an electrically insulating material, for example wood or a rigid plastic material with a thickness of about 20 mm. A cutting 14 is made in the front part of the support plate 12, cutting which is intended to receive an electrical box assembly 15.

The electrical box assembly 15 comprises an electronic card 17 on the lower part of which is fixed a battery box 18, on its upper part being fixed an LCD screen display. The electronic card 17 integrates an ASIC card constituting the electronic control unit of the device, the electronic card 17 comprising connections connecting the ASIC card to the display 19, to the power supply, as well as to a connection zone. 20. The connection area 20 receives, as will be explained below, the connections of the electrodes of the device and those of the common electrical circuit of the weight sensors.

In the central part of the upper face of the support plate is formed a recess 22 in the form of an inverted H intended to receive a connection piece 23 in the form of a lizard with arms apart. The recess 22 has a contour with conical sides and rounded edges in order to facilitate the orientation and the rapid installation of the connection piece 23. The connection piece 23 comprises, at its lateral ends, four lateral strips 24 and, in its front part, four central strips 25. The central strips 25 are provided to come into contact with the conductive tracks of the connection area 20 of the electronic card 17, while the side strips 24 are intended for direct contact with the electrodes of the device.

A faceplate 27 is affixed to the support plate 12 and forms a mounting base for the electrodes of the device. The front plate 27 comprises for this purpose, in its front part, two oval protrusions 28, 29 having the same shape and the same dimensions as the excitation electrodes 2.3, in particular their internal fixing part, and, in its rear part, two circular protuberances 30, 31 having the same shape and the same dimensions as the internal part for fixing the measurement electrodes 4,5. The protrusions 28, 29, 30, 31 each have an orifice 33 through which a lateral strip 24 of the connection piece 23 projects. A light 32 is formed in the central front part of the front plate 27 revealing the screen of the 'display 19 located below. The front plate 27 also comprises, in the lower part of the light 32, openings allowing the passage of the buttons 7 mounted to the electrical box 15.

More particularly according to the invention, the device has four electrodes 2,3,4,5 made of an electrically conductive fabric, electrodes intended for contact with the feet of the individual. Such a fabric is for example a polyester fabric with a Ni-Cu-Ni finish.

The conductive fabric is first cut and then applied to the protrusions 28, 29, 30 and 31 of the plastron 27, the fabric washers being held in place by two flanges 34.35 applied to the plastron 27. The flanges 34.35 are provided with through openings 36, 37, 38, 39 revealing the upper surface, of contact with the feet of the user, with the electrodes 2, 3, 4, 5. Each of the electrodes then comes into contact with a lateral strip 24 located below, belonging to the connection piece 23. The flanges 34, 35 are fixed to the base 8 of the device by a screw fixing 41. Several screws 41 are arranged on the periphery of the flanges 34, 35, respectively of the base 8 and thus ensure uniform tightening of the two parts and, consequently, good contact of the electrodes 2, 3, 4, 5 with the lateral strips 24 of the connection piece 23. A transparent display window 6 then completes the front of the device. All the components are thus included inside a closed space of small thickness, ensuring a compact construction of the device. In an alternative embodiment of the invention, the electrodes 2,3,4,5 are cut according to a predetermined contour, for example slightly greater than that of the protrusions 28,29,30,31, and are applied by means of a layer of adhesive on these protrusions or directly on the plate 1. The conductive fabric can in this case be advantageously produced in the form of a sticker.

Figures 3a, 3b illustrate another alternative embodiment of the electrodes according to the present invention. An electrode 43 comprises a core 48 of parallelepiped shape made of a flexible material, this core being enveloped on these lateral faces by a sheet 47 of conductive fabric. Such an assembly can be obtained from a metallized polyester fabric heat-bonded to a polyurethane mouse core. An adhesive deposit 49, for example a double-sided adhesive, is added to the assembly thus obtained, using which it is applied to the plate of the apparatus. FIG. 4 illustrates the plate 1 of a bathroom scale with two recesses 45, 46 intended to receive two electrodes 43, 44 of the type shown in FIGS. 3a and 3b. The electrical connections connecting the electrodes 43, 44 to the electronic card can be of the type shown in FIG. 2.

The material of the core 48 can be: a silicone gel, a polyurethane foam, a neoprene foam, a polyethylene foam, or any flexible material having good damping properties in contact with the soles of the feet of the user who is standing standing on platform 1 of the appliance.

The material of the sheet 47 of conductive fabric can be a metallized polyester fabric, for example having a Ni-Cu-Ni finish.

Other variants and embodiments of the invention can be envisaged without departing from the scope of these claims.

Thus, the bathroom scale may include an electrode array comprising at least five electrodes made of a conductive fabric the invention.

In another variant of the invention, the electrodes are obtained from a metal grid made from a thin perforated sheet.

Claims

1. Impedance meter with a measuring plate (1) supported by a weighing base which includes at least one weight sensor, the measuring plate being provided with at least two electrodes (2,3,4,5; 43,44) intended for contact with the feet of the individual during a measurement, said electrodes being connected to an electrical circuit for measuring the bioelectric impedance and for displaying the body composition of the individual, characterized in that said electrodes (2,3,4,5; 43,44) are made of an electrically conductive fabric.

2. Scale impedance meter according to claim 1, characterized in that the resistivity of such an electrically conductive fabric is less than 1000 Ohms / square.

3. Impedance meter according to one of claims 1 or 2, characterized in that said electrically conductive fabric is a metallized fabric.

4. Impedance meter according to one of claims 1 or 2, characterized in that said electrically conductive fabric is a metallic fabric.

5. Impedance meter according to one of claims 1 or 2, characterized in that said electrically conductive fabric is a fabric made from son comprising a core of an electrically insulating material covered with a metallic coating.

6. Bathroom scale impedance meter according to one of claims 4 or 5, characterized in that said electrically conductive fabric comprises woven, braided or meshed wires, of diameter less than 2 mm.

7. Bathroom scale impedance meter according to one of claims 1 or 2, characterized in that said electrically conductive fabric is a fabric made from son of electrically insulating material and incorporating at least one metallic conductor.

8. Impedance meter according to one of the preceding claims, characterized in that said electrically conductive fabric is applied to a flexible support.

9. bathroom scale impedance meter according to one of the preceding claims, characterized in that said electrically conductive fabric is applied by gluing on its support.

10. Personal scale impedance meter according to one of the preceding claims, characterized in that the upper face of said plate (1) for measuring the electrodes (2,3,4,5; 43,44) is a non-planar surface.

11. Impedance meter according to one of the preceding claims, characterized in that said fabric is covered with a layer of electrically conductive varnish on its face intended for contact with the feet of the user.

12. Bathroom scale impedance meter according to one of the preceding claims, characterized in that said electrodes (2,3,4,5; 43,44) are removably mounted relative to the measuring plate.