FR2691869A1 - Flat and flexible heating element with integrated connection. - Google Patents

Abstract

- The invention relates to a flexible heating element (1) comprising at least one resistive wire (2) defining a circuit (6) with at least one input strand (4) and one output strand (5), said wire being inserted between two films of electrical insulation (3, 3 ') and being connected to at least one external electrical unit by connection means (10) characterized in that the connection means consist at least of one connection tab ( 10) flexible forming an extension of the heating element (1), and comprising inserted between the two insulating films (3, 3 '), at least two connecting strands (4, 5) drawn from the circuit (6), connected to the electrical unit and having a resistivity adapted to their connection function. - Application to household appliances.

Description

FLAT AND SOFT HEATING ELEMENT

WITH INTEGRATED CONNECT

______________________

  The present invention relates to the general technical field of flexible heating elements comprising a heating circuit and a means of electrical connection to

an external source of energy.

  The present invention relates to a flexible heating element, preferably flat, comprising at least one resistive wire defining a heating circuit inserted between

two electrical insulating films.

  Such a heating element can of course be used in all areas of application requiring the heating of parts for example mechanical, or liquid, or even fluid, and the heating element according to the invention is not limited to A specific field of application Preferably, the heating element according to the invention is more particularly intended to be integrated in a household appliance, and the invention relates, for this purpose, any appliance having a heating element according to the invention, and more particularly the cooking appliances such as kettles, and irons, in

particular to steam.

  It is already known to produce flexible heating circuits comprising a resistive element obtained for example by etching a suitable conductive metal. The resistive element made for example from a copper, tin or copper alloy. aluminum is inserted, for example by a heat treatment under pressure, between two sheets of an electrical insulating material The latter may be

  polyester, silicone glass, or micanite.

  The heating element thus produced has a certain flexibility, is generally substantially flat and can have all possible circular, rectangular geometrical shapes depending on the use and the desired implantation. Conventionally, such heating elements are integrated into a structure or apparatus for providing thermal energy and are provided for this purpose with means of connection to a power source Up to now, electrical connections have always consisted of having recourse, regardless of the application considered, to a series of insulated flexible son and / or a set of insulated rigid metal bars connecting the circuit of the resistive element to the power supply or sources of power conventionally, the connection between the son of the link and the circuit bars is made by soldering, preferably tin, wire on the resistive circuit In some applica conductive adhesives or even other types of welding such as

electric welding.

  At the industrial level, and in particular in the case of the manufacture of household appliances, the use of a connection based on cables, wires or bars of the type mentioned above, which must be put in place on the appliances. household appliances, is a long, delicate operation and therefore represents a significant cost Thus, it is usually necessary to precut the son to length, isolate and possibly provide pods, then proceed to the connection with the organs to feed or to regulate, and proceed to the actual welding This series of operations is difficult to integrate into an industrial manufacturing process, especially for the production of household appliances such as

irons.

  The object of the invention is therefore to overcome the various disadvantages mentioned above and to provide a flexible heating element allowing the elimination of any additional electrical connection reported on the heating element to facilitate the

mounting said elements.

  Another object of the invention is to provide a flexible heating element on which different electrical units can be connected without the operation of

  connection itself is made more complex.

  A complementary object of the invention aims to provide a flexible heating element whose connection means have a good moisture-proofing so that they can be integrated in the appliances, in particular household appliances, intended to operate in condition.

significant relative humidity.

  The aims assigned to the invention are achieved by means of a flexible heating element comprising at least one resistive wire defining a circuit with at least one input strand and one output strand, said strand being inserted between two strands of film. electrical insulator and being connected to at least one external electrical unit by connecting means characterized in that the connecting means are constituted at least by a flexible connecting tab forming an extension of the heating element, and comprising inserted between the two insulating films, at least two connecting wires drawn from the circuit, connected to the electrical unit and having a

  resistance adapted to their connection function.

  Other features and advantages of the invention will appear and will appear in more detail in the reading

  of the description given below, with reference to the drawings

  attached, given as illustrative and non-limiting examples, in which: Figure 1 shows in a view from above, a flexible heating element according to the invention comprising a

  connecting tongue according to the invention.

  Figure 2 shows in a view from above, another variant of connecting tab according to the invention. Figure 3 shows in a view from above, a heating element according to the invention comprising a plurality of connection tongues and details of embodiment. FIG. 4 shows, in a cross-sectional view, a connection tongue according to the invention and

provided with sealing means.

  FIG. 5 shows, in a partial cross-section taken in an iron soleplate, a connection tongue according to the invention and

  provided with other sealing means.

  FIG. 6 shows, in a plan view, an iron soleplate provided with a heating element

according to the invention.

  The heating element 1 according to the invention, such as that shown in FIG. 1, consists in known manner of a resistive wire 2, of any suitable material, of the copper, aluminum, brass or other type, inserted between two sheets insulating members 3, 3 '(FIGS. 1 and 5) adhering to each other as well as to the wire 2 and whose composition is chosen according to the desired application, among materials of the PVC, polyester, polyimide type, silicone, etc. The thicknesses in play being minimal, the heating element is flexible and generally extends in a single extension plane, so that it can be considered flat Depending on the intended application, the element 1 obviously has a shape adapted to its location and the resistive wire 2 defines a circuit also adapted to the heat dissipation flow that it must provide In the

  description which follows, the heating element 1 to which it will be

  refers only for explanatory purposes, has a geometric tip shape characteristic of the heating elements to be mounted in an iron soleplate It is obvious that the geometric shape to which reference will be made is not limiting and that the A person skilled in the art can easily modify it to make it circular or rectangular, for example, in order to integrate the heating element into another electrical appliance such as household appliances.

cooking.

  The heating element 1, such as that shown in FIG. 1, comprises a resistive wire 2 defining, starting from an input strand 4 and an output strand 5, a resistive circuit 6. The resistive circuit 6 obtained by For example, by chemical cutting or serigraphic deposition advantageously presents a series of loops forming a serpentine circuit. The resistive wire 2 is intended to be connected, when the heating element is for example implanted in an iron soleplate, to an external electrical unit. constituted in this case by a power supply unit such as the sector The connection is obviously made via a power cable to be connected to the sector For this purpose, the heating element 1 comprises as connecting means a connection tab 10 forming a

  extension of the structure itself of the heating element 1.

  The connection tongue 10 extends, in the example shown in FIG. 1, outside the main geometrical envelope delimiting the heating element 1 and from the periphery of said envelope. In the embodiment shown in FIG. 1, the tongue 1 extends from the periphery 1 i formed by the rear edge of

  the heating element 1 thus constituting the attachment edge.

  In the variant embodiment shown in FIG. 1, the connection tongue 10 thus forms an external tongue, of variable length, depending on the distance of the necessary connections, and for example of square or rectangular shape. The connection tongue 10 is limited externally. by two portions of insulating film 3, 3 'and comprises inserted between these two films the two respectively inlet 4 and output 5 strands of the resistive circuit 6 In such a case the input 4 and output 5 strands constitute the main connecting strands of the circuit 6 and are intended to be connected to an electrical unit, in this case of supply For this purpose the connecting strands 4, 5 have a resistivity adapted to their connection function, obtained for example by widening their track relative to the average width of the tracks of the rest of the circuit 6 The connection tab 10 has the same internal structure as that of the rest of the heating element and therefore has the flexibility to be movable and folded out and from the main extension plane of the heating element 1 It can be connected directly to the appropriate electrical unit, simply by raising from its folding zone facing the rear edge 11, then by multidirectional deformation in the desired direction for the connection. The heating element shown in FIG. 2 differs from that shown in FIG. 1 only in the particular arrangement of the connecting means, which in this case

  are constituted by an internal connection tab 15.

  This extends at least in part, and in the variant shown in Figure 2 in full, within

  the geometric envelope delimiting the heating element 1.

  According to this variant embodiment, the connecting tongue 15 is thus formed by a re-entrant cut made from the periphery of the geometrical envelope forming the heating element 1 and preferably from the rear edge 11b. In the same way as for the first embodiment shown in Figure 1, the inner tongue 15 has a structure equivalent to that of the entire heating element and is provided with connecting strands 4 'and being in said tab. As shown in FIG. 3, the heating element according to the invention may comprise, in addition to a connection tongue 17 intended to be connected to the sector, at least one other pair of connecting strands forming strands of secondary connections 18 integrated in the resistive circuit 6 and pulled from the latter The secondary connection strands 18 may be inserted in connecting tongues similar to the external tongues 10 or internal 15, such as those shown in FIGS. 1 and 2. embodiment shown in Figure 3 the secondary connecting strands 18 are inserted into an inner tongue 19 obtained by partially cutting the insulating films 3, 3 'around the secondary connecting strands 18 The cutting line 20 remotely surrounds the secondary connection strands 18 except for an attachment edge opposite the end of the strands 18 and forming a connection zone with the rest of the Heating element The cutout may be formed by three lines a, 20b, 20c, complete or consist of simple pre-cut incisions along the same lines making it possible to initiate, at the time of assembly and connection, the clearance and in particular the recovery of the tongue 19 along the cutting line 20 previously cut The line 20b which defines the edge substantially perpendicular to the longitudinal axis of the secondary strands 18 extends at a distance from the periphery 11 C of the heating element 1 La tongue 20 is thus completely included in the heating element 1 In the heating elements 1 of the type of those shown in FIG. 3, the resistive circuit 6 may comprise several pairs or series of secondary connection strands 18, and consequently several series of internal or external connection tabs distributed along said circuit The internal or external connection tabs are intended to be connected 18, which they comprise to various electrical units connected to the electrical apparatus in which the heating element 1 is located. These electrical units may be, for example, control lamps, thermostats, electronic control pads, etc. In certain applications and especially when the heating elements according to the invention are mounted in household appliances, such as irons, it is important that the connecting tongues 10, 17 are provided with sealing means. household appliances of the type mentioned above are likely to operate in the presence of steam or moisture which must not be able to come into contact with the connecting strands 4, 5 or 18 For this purpose it is intended to dispose along the periphery of the tongues 10, 15, 17, 20 sealing means They may consist of the simple addition, gluing, for example, a ribbon 25 (FIG. 1) straddling the two insulating films 3, 3 'and extending at least over the end edge 26 of the tongue 10. The ribbon 25 may be chosen from any material having good properties

insulation to moisture.

  The sealing means may also consist, as shown in FIG. 4, in a folding of the lower insulating film 3 'on the other insulating film 3 The superposition of the films 3 and 3' extends over a sufficient length to come close the front end edge 27 of the tongue 10 Conversely, the upper insulating film 3 may be of greater length than the lower insulating film 3 'and folded on the latter In these embodiments, the connecting strands 4 and 5 which end the front end edge 27 are protected

  against any penetration of moisture.

  Figures 5 and 6 show an iron soleplate comprising a lower ironing plate 30 forming the heat-emitting plate, on

  which is fixed a upper retaining plate 31.

  The heating element 1 according to the invention is held in place by compression and by gluing between the plates and 31. The holding plate 31 is provided with a series of notches 32 arranged opposite the connection tongues 10, 15, 17, so as to form windows for the passage of the latter The electric units of the iron to be connected to the resistive circuit 6 are located at a level higher than that of the plate 31, it is possible to raise by folding the connecting tongues 10, 15, 17 through the notches 32 In FIG. 6, the notch 32 is arranged to allow the lifting of a connecting tongue 19 for connecting the connecting strands.

  secondary 18 to the edges of a thermostat 35.

  The assembly of the rear connector 36 (FIGS. 5 and 6) comprises an internal tongue 15 adhering by its upper face formed by the insulating film 3 on a movable tab 37 resulting from the partial or total cutting of a notch 32. movable tab 37 consists of a cut piece in the holding plate 31 so as to be connected thereto by

  one and preferably two deformable link arms 38.

  In the example shown in FIG. 6, the mobile tab 37 is of H-like shape, defining two external legs from the link arms 38. Advantageously, the resistive circuit 6 can be completely or partially surrounded by a inert resistive track, as shown in Figure 2, comprising for example two lateral strands 40a so as to follow the connecting strands 4, 4 'or 18 The strands 40 a as the whole of the inert track 40 are obviously inserted between the two sheets of insulating film 3, 3 'If necessary, the inert resistive track 40 can also completely surround the resistive circuit 6 and come to extend parallel and at the distance from the edge 26 of the tongue 10, 15 or 20 The lateral strands 40a are arranged in the connecting tongue 10, 15, 20 so that the legs 39 of the mobile tab 37 cover said strands 40a completely. Thus, during the production of a heating element according to the invention, each insulating film 3, 3 'comprising a layer of adhesive on its two opposite faces, the production of the heating structure can take place by pressing, directly in place between the two plates 30, 31 The sizing operation is simplified and the sealing of the heating element is particularly improved at the connecting strands 4, 5 Indeed, the presence of the movable tab 37 allows a gluing on the entire surface of the film 3 of the heating element, which represents a not insignificant simplification of the sizing process in itself on the one hand, and allows during the application of the holding plate 31 a pressing and gluing of the connection tab Against the central surface and the legs 39 of said plate The outer face of the tongue 10, 15, 19, formed by a portion of the film 3 'is not glued or is provided with a film

  additional preventing its adhesion on the plate 30.

  The overall tightness of the tongue 15 is thus ensured on the one hand by the compression of the strands 40a by the legs 39, and on the other hand by the compression of the insulating films 3, 3 'against each other , against the strands of

connection 4, 5.

  As shown in FIG. 5 for example, the mobile tab 37 can be raised from its initial plane of extension P parallel to the plane of extension of the soleplate so as to occupy, for example, a connection position in which the extension plane P 'extends substantially perpendicular to said plane P The tongue 15 can be raised to occupy any intermediate position such that P'1 or P'2, from a rotation of the movable plate 37 around a fictitious axis passing through the two arms of laison 38 and extending in the plane P It should be noted that due to the rigidity of the plate 31 the chosen spatial position of the tongue 15

is stable.

  The number of connecting strands thus inserted between the two sheets of insulating material 3, 3 'is not limited and as shown in FIG. 3 for example, three connecting strands 41, 42, 43 can be used. extend in the

tongue 17.

  Once the heating element 1 according to the invention is put in place in an electrical appliance, the actual connection between the connection wires 4, 5, 18 or 41, 42, 43 and the terminals of the electrical units can be realized. In other ways, it is possible, for example, to fix the connecting strands 4 or 5 to the terminals of the electrical apparatus using screws passing through the thickness of said connecting strands. It is possible to use additional fastening means such as staples 45 (FIG. 3) fixed directly through each connecting strands 41, 42 or 43 in a particularly advantageous manner. The staples 45 also pass through their fixing studs,

  the thickness of the insulating films 3, 3 '.

  The electrical assembly comprising the heating element according to the invention therefore no longer includes son, cables or connecting bars connecting the heating structure with the various electrical units of the device Indeed, thanks to the flexible connection tabs freely extending the heating structure and the resistive circuit in the form of dab, it is possible to fold said tongue to conform it in space and put it in relation with the connection terminal, thus making it fulfill a function equivalent to that of a wire connection The actual mounting is also greatly simplified In addition, in specific applications relating to household appliances likely to come into contact with moisture, the use of a sealing means, such as a tab mobile 37, not only keeps the mobility required for the connection tab 15, but also connection. preserve the tightness of the strands of

Claims (15)

R E V E N D I C A T IO N S   A flexible heating element (1) comprising at least one resistive wire (2) defining a circuit (6) with at least one input strand (4) and an output strand (5), said strand being inserted between two strands of film electrical insulator (3, 3 ') and being connected to at least one external electrical unit by connection means (10, 15, 19), characterized in that the connecting means are constituted by at least one connecting tongue (10). ,, 19) forming an extension of the heating element (1), and comprising inserted between the two insulating films (3, 3 '), at least two connecting strands (4, 5, 18) drawn from the circuit (6, )> connected to the electrical unit and having a resistivity   adapted to their connection function.   2 heating element according to claim 1 characterized in that it comprises a tongue (10) which extends outside and from the geometric envelope (11) defining said heating element, to form a external tab.   3 heating element according to claim 1 or 2 characterized in that it comprises a tongue (15, 19) which extends at least partly inside the geometric envelope (11) delimiting said heating element and from a fastening edge located inside said envelope, to form a internal tongue.   4 heating element according to claim 3 characterized in that the inner tongue (19) is obtained by partial cutting of the insulating films (3, 3 ') around the connecting strands, said tongue (19) being   completely included in the heating element (1). 1 L +   Heating element according to one of the claims from 1 to   4 characterized in that the connecting strands (4,) are formed by the input strand (4) and the strand of output (5) of the circuit (6).   6 heating element according to claim 5 characterized in that the circuit (6) comprises secondary connection strands (18) inserted in internal or external connection tongues (10, 15, 19), intended to be connected by the strands qu 'they include electrical units such as lamps, thermostat, electronic pads   Heating element according to one of the claims   characterized in that the connecting tongues (10, 15, 19) are provided with sealing means (3, 3 ', 25, 37, 40 a) arranged along the   the periphery of said tongue.   8 heating element according to claim 7 characterized in that the sealing means consist of a folding of one of the insulating films (3, 3 ') on the other insulating film to a length sufficient to close the terminal edge ( 27) of the tongue (10, 15, 19) near which the strands of connection (4, 5, 18).   9 heating element according to claim 7 or 8 characterized in that the sealing means consist of a ribbon (25) fixed astride the two insulating films (3, 3 ') and extending at least over the   end edge (26) of the tongue.   Heating element according to one of the claims   characterized in that it extends between two metal plates (30, 31) to which it adheres by gluing, one of the plates forming a heat-emitting plate (30), the other forming a holding plate (31). ) provided at the level of one or more 1.5-connection tabs (10, 15, 19) of a movable tab (37) adhered on one side by the connecting tab (10, 15, 19), said tab allowing the lifting of the tongue.   11 heating element according to claim 10 characterized in that the movable tab (37) consists of a cut piece in the holding plate (31) to which it is connected by at least and preferably   two link arms (38) deformable.   12 heating element according to claim 11 characterized in that the movable tab (37) is shaped like an H whose two outer legs (39) seal the tongue (10, 15, 19) by compressing the strands (40 a) of an inert resistive track (40)   inserted between the two insulating films (3, 3 ').   Heating element according to one of Claims 1 to 12   characterized in that the connecting strands (4, 5, 18) are connected directly to the electrical unit by means of fixing means, such as screws, crossing said strands.   Heating element according to one of Claims 1 to 12   characterized in that the connecting strands (4, 5, 18) are connected to the electrical units by means of staples (45) fixed directly through each strand (4, 5, 18) and the insulating films (3, 3 ').   Domestic appliance having a heating element   according to one of claims 1 to 14.   16 household appliance according to claim 15 characterized in that it consists of an iron.