Electrical resistance of the so-called band type

Description

[0001] The current invention refers to an electrical resistance of the so-called band or type, based on the traditional use of a wrapped laminar sheet made of a crystallized mineral with high dielectric strength and chemical stability such as mica.

[0002] It is known that the electrical resistances of the band type are currently made according to numerous constructive types, each marked by technical and functional peculiarities suitable for several applications and multiple uses.

[0003] In general, the band electrical resistances can be classified in nozzle band resistances, band resistances with mica insulation and ceramic band resistances.

[0004] In particular, the technical field mostly involving the present invention refers to band electrical resistances with mica insulation, especially suitable for heating flat surfaces in contact or irradiation, inserted into hollow bodies for heating metallic masses.

[0005] Said band electrical resistances with mica insulation having the features disclosed in the preamble of the appended claim 1 are known for example from GB 121210 A.

[0006] Typical applications of the mica band electrical resistances are represented in industrial circle by injection and extrusion cylinders of the machines for plastic material working, planes for presses, moulds for plastic materials, ovens, test benches, incubators, packaging machines, woodworking machines, electrical rooms, medical scientific equipment and even more.

[0007] In addition, the electrical resistances of the band type are also used in small appliances, irons, curling-tongs, cosmetics, plates for person's hair stretching and the like.

[0008] Traditionally, an electrical resistance of the so-called band kind of known type comprises a laminar base element, a sheet of substantially rectangular shape made of material with high dielectric strength, which is precisely the mica.

[0009] The electrical resistance in exam also includes a resistive wire, usually a strip of rectangular cross section, which is electrically connected, according to a proper circuit diagram, with an electricity source.

[0010] In particular, the resistive wire is wrapped around the laminar base element resulting close to a plurality of surface sectors surface of the outer edges of the laminar element itself.

[0011] Generally, such an electrical resistance also comprises two laminar shield supports, made of mica as well and arranged so as to cover the resistive wire coupled with the laminar base element in order to prevent contacts with an outer metallic shell, such as a tin or electro-zinced sheet iron, through which the transmission to the mass to be heated of the thermal energy produced by the resistive wire wrapped around the laminar base element takes place.

[0012] The electrical resistances of known type just described in their essential features, although distinguished by high application flexibility and good performances, in any case present the recognized drawback of sometimes leading to the collapse of the resistive wire when it reaches high operating temperatures for several times, in the order, for example, of 400÷600°C.

[0013] Indeed, under these operating conditions of the electrical resistance, the laminar base element made of mica expands, undergoing to traction the resistive wire placed close to the surface sectors of the outer edges of the laminar element till to often cause structural failure and, more in general, the substantive inefficacy of the electrical resistance, with the consequent need to operate repair or, more properly, replacement interventions of the resistive wire, still expensive and therefore undesired.

[0014] The present invention aims to overcome the drawback of the known technique just mentioned.

[0015] In particular, main purpose of the invention is to provide an electrical resistance of the so-called band type which compared to electrical resistances of the known type eliminates or at least drastically limits the risks of structural failure of the resistive wire and, therefore, a malfunction or, more realistically, a substantial inability to use the electrical resistance itself.

[0016] Within such a purpose, it is a first task of the present invention to carry out an electrical resistance of the so-called band type which, compared to the prior art allows to reduce the interventions for its maintenance, repair and/or replacement, as far as the resistive wire is concerned in particular.

[0017] It is a second task of the current invention to make available an electrical resistance of the so-called band type which presents operating costs lower than the equivalent electrical resistances of known type.

[0018] It a last but not least purpose of the present invention to develop an electrical resistance of the so-called band type whose operation is more reliable than electrical resistances of the prior art.

[0019] The aforesaid purposes are achieved by means of an electrical resistance of the so-called band type according to the attached claim 1, as hereinafter referred for the sake of brevity.

[0020] Additional technical features of detail of the electrical resistance of the invention are set forth in the dependent claims.

[0021] Advantageously, the electrical resistance according to the invention is more reliable during operation than the equivalent electrical resistances of current use.

[0022] This is due to the through holes made in the laminar base element made of high dielectric strength material, usually near all the surface sectors where the resistive wire is arranged close to the laminar base element.

[0023] These through holes, indeed, allow to avoid or at least limit the expansion phenomenon, along its own longitudinal axis, of the laminar base element in case of high operating temperatures of the resistive wire, discharging the negative effects of this phenomenon through the instant breaking the intermediate tongue interposed between the through holes and the surface sectors of the laminar element on which the resistive wire rests.

[0024] In this way, the laminar base element cannot undergone to traction the resistive wire, preventing or significantly averting the negative effect of the structural failure for fatigue breakage of the latter, which can be typically found in similar known electrical resistances.

[0025] Still advantageously, the electrical resistance of the subject invention is easy to produce.

[0026] Equally advantageously, compared to the prior art the invention allows to reduce the maintenance, repair and/or replacement interventions of the components of band type electrical resistances, mostly with regard to the resistive wire.

[0027] In advantageous manner, therefore, the electrical resistance of the invention has operating costs lower than similar electrical resistances of the prior art.

[0028] Said purposes and advantages, as well others that will emerge further on, will greatly appear from the description that follows, related to preferred embodiments of the electrical resistance of the invention, given by way of illustrative and indicative, but not limiting, example with reference to the attached drawing tables where:

• figure 1 is a simplified side view of the electrical resistance of the invention;
• figure 2 is a side view of a particular of figure 1;
• figure 3 is an enlarged view of a particular of figure 1 in an operating condition different from that one of figure 1 and subsequent to the reaching of critical temperature conditions;
• figure 4 is a simplified side view of an executive variant of the resistance of figure 1;
• figure 5 is a side view of a particular of figure 4.

[0029] The electrical resistance of the so-called band or collar type, object of the invention and suitable to be used on industrial machines, irons, curling-tongs or small appliances, just to name a few of its applications, is shown in figure 1 where it is globally numbered with 1.

[0030] As it can be seen, the electrical resistance 1 includes a laminar base element 2, made of high dielectric strength material, and a resistive wire 3, suitable to be electrically connected with an electric power source, not represented.

[0031] Furthermore, the resistive wire 3 is wrapped around the laminar base element 2 resulting close to a plurality of surface sectors 4 defined in both the outer edges 2a, 2b of the laminar base element 2.

[0032] According to the invention, the laminar base element 2 presents near each of the surface sectors 4 a through hole 5 allowing the resistive wire 3, when it reaches high operation temperatures, about 400÷600 °C, to cause the collapse of an intermediate tongue 6 defined between each surface sector 4 and the through hole 5.

[0033] In essence, the peculiarities of the electrical resistance 1, which however represent a first embodiment of the invention, consists in that it comprises a plurality of through holes 5, one for each of the four surface sectors 4 at which the resistive wire 3 is close to the laminar base element 2, so that the through holes 5 are aligned each other along a longitudinal direction X' parallel to the longitudinal axis X defined by the laminar base element 2 itself.

[0034] It should be emphasized again that the surface sectors 4 are in this case defined along each of the outer edges 2a, 2b of the laminar base element 2, as well as the through holes 5 are made near each of these outer edges 2a, 2b.

[0035] Preferably but not necessarily, the laminar base element 2 presents a substantially rectangular profile in side view and a thickness not exceeding 1 mm, for example equal to 5 tenths of millimetre.

[0036] More specifically, the laminar base element 2 mainly develops along to the aforesaid longitudinal axis X.

[0037] In this case, furthermore, the laminar base element 2 presents a plurality of tapered notches 7 made in each of its outer edges 2a, 2b into which the resistive wire 3 is firmly received.

[0038] In particular, as figure 2 better shows, the bottom walls inferiorly delimiting the related tapered notches 7 define the surface sectors 4 firstly introduced which, therefore, belong to planes staggered with respect to the plane defined by the outer edges 2a, 2b.

[0039] The material of the laminar base element 2 is preferably a crystallized mineral such as mica, well-known electric heat resistant insulator.

[0040] The resistive wire 3 includes a strip made of metallic material, according to what is known to the person skilled in the art.

[0041] The intermediate tongue 6 has a height not exceeding 1.5 mm: in preferred but not bounding way, such a height presents a value of 1 mm.

[0042] Figure 2 highlights also that each through hole 5 defines a linear axis Z orthogonally intersecting the side faces 2c, 2d of the laminar base element 2, thus resulting perpendicular to the longitudinal axis Y.

[0043] In addition, each through hole 5 presents a centre placed at a prefixed distance from the outer edge 2a closest to it of the laminar base element 2.

[0044] More in detail, each through hole 5 mainly develops along the linear direction X' parallel to the longitudinal axis X and along which presents a size L₁ lower than the width L₂ of each of the surface sectors 4, chiefly that one directly facing it.

[0045] Such a constructive design ensures a greater bearing capacity for each of the surface sectors 4 on which the resistive wire 3 is placed close to, conversely increasing the structural strength of the intermediate tongue 6.

[0046] Figure 2 also shows that, at purely preferential title, each of the through holes 5 presents a profile of rectangular shape in longitudinal section, whose base is represented by the size L₁ just cited.

[0047] It is also highlighted that the centres of the through holes 5 are spaced apart each other by a regular pitch P which however coincides with the pitch spacing apart each other the midpoints M of the surface sectors 4.

[0048] It is understood that in further invention embodiments, the through holes can have a profile which differ from the rectangular one, as well as embodiments may exist in which the through holes made in the same laminar base element have profiles which differ each other.

[0049] As shown in figure 3, once yielding of the intermediate tongue 6 has occurred, the resistive wire 3 is placed close to the bottom wall 5a that, in the operating conditions of the electrical resistance 1 which can be found before such a yielding, delimits the through hole 5 and that, due to the aforesaid yielding, is actually the new surface sector of support of the resistive wire 3: in this case, along the size L₁ the bottom wall 5a is narrower than the surface sector 4 that it replaces.

[0050] Figures 4 and 5 show a possible execution variant of the invention where the electrical resistance of the so-called band type, now globally indicated with 50, differs from that one previously described and marked with 1 for the different shape of the laminar base element 51.

[0051] More precisely, the laminar base element 51 has outer edges 51 a, 51 b completely regular and linear, devoid of those tapered notches of the laminar base element 2.

[0052] It follows that the resistive wire 52 is placed close to the surface sectors 53 directly belonging to each of the outer edges 51 a, 51 b of the laminar base element 51.

[0053] It has to be noted that the through holes 54 take the same position, the same profile and the same sequence along the longitudinal direction X' of the through holes 5 made in the laminar base element 2 of the electrical resistance 1 previously described.

[0054] Operatively, in the common operating conditions, the electrical resistance 1 takes the configuration of figure 1, with the resistive wire 3 connected with an electricity power source and wrapped around the laminar base element 2 so as to be inserted for some sections in the tapered notches 7.

[0055] When, for whatever reason, usually after more operating cycles, the resistive wire 3 overheats up to a temperature to be considered high, higher than 300°C, it causes the longitudinal expansion of the laminar base element 2 made of high dielectric strength material such as mica.

[0056] This causes the collapse of the intermediate tongue or support bridge 7 and the complete opening of the various through holes 5 affected by this phenomenon, so that the wire resistive 3 lies on the bottom wall 5a of the aforesaid through holes 5, taking the configuration of figure 3 without sustaining tensile forces that cause the harmful and undesired structural failure.

[0057] The operation of the electric resistance 50, which normally takes the configuration of figure 4, is fully similar to that one described for the electric resistance 1.

[0058] Based on the foregoing, it is, therefore, understood that the electrical resistance of the so-called band type of the invention achieves the purposes and reaches the advantages previously mentioned.

[0059] In execution, changes will be made to the electrical resistance of the invention consisting, for example, in a number of laminar base elements different from that one on which the previous discussion has been based and illustrated in the appended drawings: for example, the laminar base elements will typically be two in number.

[0060] It is obvious that, in such cases, the electrical resistance will include a pair of resistive wires, one for each of the laminar base elements.

[0061] Furthermore, in other embodiments of the invention, not shown, the resistive wire can be placed close to a number of surface sectors of the laminar base element different from that one shown in the following drawings, consequently varying also the positioning of one or more of the through holes facing to aforesaid contact surface sectors.

[0062] Moreover, in further embodiments of the electrical resistance here claimed, always not represented, the resistive wire could be located arranged close to a plurality of surface sectors of only one of the outer edges of the laminar base element, which does not affect the advantage brought by the present invention.

[0063] Beyond this, other embodiments of the invention could provide that the through holes are made only near a few of the surface sectors in which the resistive wire is in contact with the base laminar base e element.

[0064] Moreover, in further embodiments of the electrical resistance of the invention, not shown, the through holes could be aligned and, preferably, equally spaced apart each other along several longitudinal directions parallel each other and to the longitudinal axis defined by the laminar base element.

[0065] In this case, the through holes will be aligned each other even along a further longitudinal direction orthogonal to the longitudinal axis of the laminar base element, resulting, preferably but not necessarily, equally spaced apart each other through an intermediate tongue of the type previously described, suitable to collapse in order to release traction tension suffered by the resistive wire when the latter reaches hot operating temperatures.

[0066] It is finally specified that the electrical resistance of the so-called band type of the invention could include, especially in case it is of armoured type, all the other components generally provided for these industrial items, such as a couple of support layers made of mica arranged close to the resistive wire so as to isolate it and prevent contact with the outer metallic shell (or envelope) used to transmit thermal heat produced by the resistive wire to the mass.

[0067] It is clear that many other changes may be made to the electrical resistance in exam, without departing from the principle of novelty intrinsic in the inventive idea expressed here, as it is clear that, in the practical implementation of the invention, materials, shapes and sizes of the illustrated details can be changed, as needed, and replaced with others technically equivalent.

[0068] Where the constructive features and techniques mentioned in the following claims are followed by reference numbers or signs, those reference signs have been introduced with the sole objective of increasing the intelligibility of the claims themselves and therefore they have no limiting effect on the interpretation of each element identified, by way of example only, by these reference signs.

Claims

1. Electrical resistance (1; 50) of the so-called band type comprising at least one laminar base element (2; 51); made of high dielectric strength material, and at least one resistive wire (3; 52), suitable to be electrically connected with an electricity source and wrapped around said laminar element (2; 51), said resistive wire (3, 52) being also placed close to a plurality of surface sectors (4; 53) of at least one of the outer edges (2a, 2b; 51 a, 51 b) of said laminar element (2; 51), characterized in that said laminar base element (2; 51) presents near one or more of said surface sectors (4, 53) at least one through hole (5; 54) suitable to allow said resistive wire (3; 52), when it reaches high operating temperatures, to cause yielding of at least one intermediate tongue (6) defined between at least one of said surface sectors (4; 53) and said through hole (5; 54).

2. Resistance (1; 50) as claim 1) characterized in that said laminar base element (2; 51) mainly develops along a longitudinal axis (X) and said material with which said laminar base element (2; 51) is made consists of mica.

3. Resistance (1; 50) as claim 1) or 2) characterized in that said through hole (5; 54) defines a linear axis (Z), incident orthogonally the side faces (2c, 2d) opposed each other of said laminar base element (2; 51) and orthogonal to said longitudinal axis (X), and presents a centre placed at a prefixed distance from one of said outer edges (2a, 2b; 51 a, 51 b) closest to it of said laminar base element (2; 51).

4. Resistance (1; 50) as any of the previous claims characterized in that said intermediate tongue (6) presents a height not exceeding 1.5 mm.

5. Resistance (1; 50) as any of the previous claims characterized in that said through hole (5; 54) presents a profile which mainly develops along a linear direction (X') parallel to said longitudinal axis (X) and along which it presents a size (L₁) greater than the width (L₂) of each of said surface sectors (4; 53).

6. Resistance (1; 50) as any of the previous claims characterized in that said through hole (5; 54) presents a rectangular shape profile in longitudinal section.

7. Resistance (1; 50) as any of the previous claims characterized in that once yielding of said intermediate tongue (6) has occurred, said resistive wire (3; 52) is placed near the bottom wall (5a) which, in the operating conditions verifiable before said yielding, delimits said through hole (5; 54) and which, following to said yielding, replaces one of said surface sectors (4; 53).

8. Resistance (1; 50) as claim 1) characterized in that it includes a plurality of through holes (5; 54), one at each of said surface sectors (4; 53) in which said resistive wire (3; 52) is placed close to said laminar base element (2; 51), so that said through holes (5; 54) are aligned each other along at least one linear direction (X') parallel to said longitudinal axis (X).

9. Resistance (1; 50) as the claim 8) characterized in that the midpoints of said surface sectors (4; 53) and the centres of said through holes (5; 54) are spaced apart each other by a regular pitch (P).

10. Resistance (1; 50) as any of the previous claims characterized in that said surface sectors (4; 53) are defined along each of said outer edges (2a, 2b; 51 a, 51 b) of said laminar base element (2; 51) and said through holes (5, 54) are made near each of said outer edges (2a, 2b; 51 a, 51 b) of said laminar base element (2; 51).

Ansprüche

1. Elektrischer Widerstand (1; 50) vom so genannten Bandtyp, umfassend mindestens ein laminares Basiselement (2; 51), das aus Material hoher dielektrischer Festigkeit hergestellt ist, und mindestens einen Widerstandsdraht (3; 52), der geeignet ist, elektrisch mit einer Elektrizitätsquelle verbunden zu sein, und um das laminare Element (2; 51) gewikkelt ist, wobei der Widerstandsdraht (3; 52) auch nahe zu einer Vielzahl von Oberflächensektoren (4; 53) von mindestens einer der äußeren Kanten (2a, 2b; 51a, 51b) des laminaren Elements (2; 51) platziert ist, dadurch gekennzeichnet, dass das laminare Basiselement (2; 51) nahe einem oder mehreren der Oberflächensektoren (4; 53) mindestens eine Durchbrechung (5; 54) zeigt, die geeignet ist, dem Widerstandsdraht (3; 52), wenn er hohe Betriebstemperaturen erreicht, zu erlauben, ein Fließen von mindestens einer Zwischenzunge (6) zu veranlassen, die zwischen mindestens einem der Oberflächensektoren (4; 53) und der Durchbrechung (5; 54) definiert ist.

2. Widerstand (1; 50) gemäß Anspruch 1), dadurch gekennzeichnet, dass das laminare Basiselement (2; 51) sich hauptsächlich entlang einer longitudinalen Achse (X) entwikkelt und das Material, mit dem das laminare Basiselement (2; 51) hergestellt ist, aus Glimmer besteht.

3. Widerstand (1; 50) gemäß Anspruch 1) oder 2), dadurch gekennzeichnet, dass die Durchbrechung (5; 54) eine lineare Achse (Z) definiert, einfallend senkrecht zu dem einander gegenüberliegenden Seitenflächen (2c, 2d) des laminaren Basiselements (2; 51) und senkrecht zu der longitudinalen Achse (X), und eine Mitte zeigt, die mit einem vorbestimmten Abstand von einer der äußeren Kanten (2a, 2b; 51a, 51b), die am nächsten zu ihr ist, des laminaren Basiselements (2; 51) platziert ist.

4. Widerstand (1; 50) gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Zwischenzunge (6) eine Höhe zeigt, die 1.5 mm nicht überreicht.

5. Widerstand (1; 50) gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Durchbrechung (5; 54) ein Profil zeigt, das sich hauptsächlich entlang einer linearen Richtung (X') parallel zu der longitudinalen Achse (X) entwickelt und entlang der es eine Größe (L₁) größer als die Breite (L₂) von jedem der Oberflächensektoren (4; 53) präsentiert.

6. Widerstand (1; 50) gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Durchbrechung (5; 54) im Längsschnitt ein rechteckiges Formprofil zeigt.

7. Widerstand (1; 50) gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass wenn das Fließen der Zwischenzunge (6) aufgetreten ist, der Widerstandsdraht (3; 52) nahe der Bodenwand (5a) platziert ist, die in den Betriebsbedingungen, die vor dem Fließen verifizierbar sind, die Durchbrechung (5; 54) begrenzt und die, dem Fließen folgend, einen der Oberflächensektoren (4; 43) ersetzt.

8. Widerstand (1; 50) gemäß Anspruch 1, dadurch gekennzeichnet, dass er eine Vielzahl von Durchbrechungen (5; 54) enthält, eine an jedem der Oberflächensektoren (4; 53), in denen der Widerstandsdraht (3; 52) nahe dem laminaren Basiselement (2; 51) platziert ist, so dass die Durchbrechungen (5; 54) miteinander entlang mindestens einer linearen Richtung (X') parallel zu der longitudinalen Achse (X) ausgerichtet sind.

9. Widerstand (1; 50) gemäß Anspruch 8), dadurch gekennzeichnet, dass die Mittelpunkte der Oberflächensektoren (4; 53) und die Mitten der Durchbrechungen (5; 54) voneinander durch ein regelmäßiges Abstandsmaß (P) beabstandet sind.

10. Widerstand (1; 50) gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Oberflächensektoren (4; 53) entlang jeder der äußeren Kanten (2a, 2b; 51a, 51b) des laminaren Basiselements (2; 51) definiert sind und die Durchbrechungen (5, 54) nahe von jeder der äußeren Kanten (2a, 2b; 51a, 51b) des laminaren Basiselements (2; 51) hergestellt sind.

Revendications

1. Résistance électrique (1 ; 50) du type appelé à bande, comprenant au moins un élément de base laminaire (2 ; 51), réalisé en un matériau à haute résistance diélectrique, et au moins un fil résistif (3 ; 52), approprié pour être électriquement connecté à une source d'électricité et enveloppant tout autour ledit élément laminaire (2 ; 51), ledit fil résistif (3 ; 52) étant également disposé à proximité d'une pluralité de secteurs de surface (4 ; 53) d'au moins l'un des bords extérieurs (2a, 2b ; 51a, 51 b) dudit élément laminaire (2 ; 51), caractérisée en ce que ledit élément de base laminaire (2 ; 51) présente au voisinage de l'un ou de plusieurs desdits secteurs de surface (4 ; 53) au moins un trou traversant (5 ; 54) approprié pour permettre audit fil résistif (3 ; 52), lorsqu'il atteint des températures de fonctionnement élevées, de provoquer une déformation d'au moins une languette intermédiaire (6) définie entre au moins l'un desdits secteurs de surface (4 ; 53) et ledit trou traversant (5 ; 54).

2. Résistance (1 ; 50) selon la revendication 1, caractérisée en ce que ledit élément de base laminaire (2 ; 51) se développe principalement le long d'un axe longitudinal (X) et en ce que ledit matériau avec lequel est réalisé ledit élément de base laminaire (2 ; 51) est constitué de mica.

3. Résistance (1 ; 50) selon la revendication 1 ou 2, caractérisée en ce que ledit trou traversant (5 ; 54) définit un axe linéaire (Z), incident de façon orthogonale vis-à-vis des faces latérales (2c, 2d) opposées l'une à l'autre dudit élément de base laminaire (2 ; 51) et orthogonal audit axe longitudinal (X), et présente un centre situé à une distance prédéfinie vis-à-vis de l'un desdits bords extérieurs (2a, 2b ; 51 a, 51 b) le plus près de celui-ci dudit élément de base laminaire (2 ; 51).

4. Résistance (1 ; 50) selon l'une quelconque des revendications précédentes, caractérisée en ce que ladite languette intermédiaire (6) présente une hauteur ne dépassant pas 1,5 mm.

5. Résistance (1 ; 50) selon l'une quelconque des revendications précédentes, caractérisée en ce que ledit trou traversant (5 ; 54) présente un profil qui se développe principalement le long d'une direction linéaire (X') parallèle audit axe longitudinal (X) et le long de laquelle il présente une taille (L₁) supérieure à la largeur (L₂) de chacun desdits secteurs de surface (4 ; 53).

6. Résistance (1 ; 50) selon l'une quelconque des revendications précédentes, caractérisée en ce que ledit trou traversant (5 ; 54) présente un profil de forme rectangulaire en section longitudinale.

7. Résistance (1 ; 50) selon l'une quelconque des revendications précédentes, caractérisée en ce qu'une fois que la déformation de ladite languette intermédiaire (6) s'est produite, ledit fil résistif (3 ; 52) est disposé au voisinage de la paroi inférieure (5a), qui, dans les conditions de fonctionnement vérifiables avant ladite déformation, délimite ledit trou traversant (5 ; 54), et qui, après ladite déformation, remplace l'un desdits secteurs de surface (4 ; 53).

8. Résistance (1 ; 50) selon la revendication 1, caractérisée en ce qu'elle comprend une pluralité de trous traversants (5 ; 54), à raison d'un à chacun desdits secteurs de surface (4 ; 53) dans lesquels ledit fil résistif (3 ; 52) est disposé au voisinage dudit élément de base laminaire (2 ; 51), de telle sorte que lesdits trous traversants (5 ; 54) soient alignés les uns avec les autres le long d'au moins une direction linéaire (X') parallèle audit axe longitudinal (X).

9. Résistance (1 ; 50) selon la revendication 8, caractérisée en ce que les points milieux desdits secteurs de surface (4 ; 53) et les centres desdits trous traversants (5 ; 54) sont espacés les uns des autres d'un pas régulier (P).

10. Résistance (1 ; 50) selon l'une quelconque des revendications précédentes, caractérisée en ce que lesdits secteurs de surface (4 ; 53) sont définis le long de chacun desdits bords extérieurs (2a, 2b ; 51a, 51 b) dudit élément de base laminaire (2 ; 51) et en ce que lesdits trous traversants (5 ; 54) sont réalisés au voisinage de chacun desdits bords extérieurs (2a, 2b ; 51 a, 51 b) dudit élément de base laminaire (2 ; 51).

Drawing