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EP0080393A1 - Bi-metal device connected in series to a heater - Google Patents

Bi-metal device connected in series to a heater Download PDF

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Publication number
EP0080393A1
EP0080393A1 EP82402022A EP82402022A EP0080393A1 EP 0080393 A1 EP0080393 A1 EP 0080393A1 EP 82402022 A EP82402022 A EP 82402022A EP 82402022 A EP82402022 A EP 82402022A EP 0080393 A1 EP0080393 A1 EP 0080393A1
Authority
EP
European Patent Office
Prior art keywords
bimetallic strip
heater
face
opposite
strip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP82402022A
Other languages
German (de)
French (fr)
Other versions
EP0080393B1 (en
Inventor
Dominique Moreau
Pierre Duchemin
Francis Castel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telemecanique SA
Original Assignee
La Telemecanique Electrique SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by La Telemecanique Electrique SA filed Critical La Telemecanique Electrique SA
Publication of EP0080393A1 publication Critical patent/EP0080393A1/en
Application granted granted Critical
Publication of EP0080393B1 publication Critical patent/EP0080393B1/en
Expired legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10Operating or release mechanisms
    • H01H71/12Automatic release mechanisms with or without manual release
    • H01H71/14Electrothermal mechanisms
    • H01H71/16Electrothermal mechanisms with bimetal element
    • H01H71/164Heating elements

Definitions

  • the invention relates to a device for detecting current overcurrents, in particular for a protection device, comprising in a housing, on the one hand, a bimetallic strip having a first fixed fixed end and a second free end which is capable of actuating, directly or indirectly, a safety switch fixed in the housing and, on the other hand, an insulated electric heater which is placed in "good thermal contact along the bimetallic strip and one end of which is connected at a point in the bimetallic strip located between the ends, so that the current to be monitored crosses the heater and the bimetallic strip.
  • Such devices are widely used in protective devices, such as thermal relays, the function of which is to indirectly open the supply circuit of a consumer device to be monitored when the intensities of the currents passing through it exceed, during a certain time, a particular setpoint.
  • the heater is generally produced in the form of a coil of resistant wire placed around the bimetallic strip.
  • the first condition means that the device must have a response time greater than a standardized value for current overloads of the order of six times the nominal current.
  • the second condition means that the device containing the protective device must not be too large and that the same protective device case must be able to contain different protective devices to be used with nominal current currents. different.
  • the value of the ratio between these two resistances influences the response time; when the power dissipated in the bimetallic strip is preponderant, the response time is shorter than in the opposite case; this response time also becomes shorter when the heater is coiled over the entire length of the bimetallic strip; too short a response time may cause the protective device to trip prematurely.
  • Bimetallic devices and coiled heater have the advantage of good mechanical strength when short-circuit currents appear due to the weak electro-dynamic forces which appear between the bimetallic strip, where the direction of the current circulates longitudinally and the turns of the heater, where the direction of the current is perpendicular to the previous one.
  • the invention therefore proposes to provide a bimetallic device and heater capable of being traversed by a large nominal current which is capable of having a response time that meets the requirements and which benefits from good mechanical resistance, when the The bimetallic strip that it uses has dimensions which have been chosen in advance to meet lower nominal currents, for which a coiled heater is entirely satisfactory.
  • the heater consists of a thin strip of copper material, a good current conductor, which is placed longitudinally along a portion of the first longitudinal face of the bimetallic strip, from which it is separated by a thin insulating sheet and which is applied to this sheet by a multiplicity of deformable lateral tabs which bypass the two edges of the bimetallic strip and the ends of which rest on a second longitudinal face opposite the first face.
  • Such a device does not allow an easy adaptation of the response time insofar as one cannot then benefit from the speed of deformation provided by a bimetallic strip which heats up directly in its mass; by elsewhere, the need to fold the copper strip to locate the current input and output in the vicinity of the bimetal root does not provide good thermal efficiency and requires the use of two electrical connection parts instead of a.
  • a protective device visible in FIG. 1, comprises a box 1 having a multiplicity of housings of given length m such as 2, in each of which is disposed a device for detecting overcurrents 3; this box which can contain other organs has been deliberately limited in size in the figure.
  • Each device such as 3 is connected, on the one hand, to a current input terminal 4 connected to a phase R of a supply network and, on the other hand, directly or not to a current output terminal 5 which is connected by a conductor to a corresponding terminal of a current consuming device, not shown.
  • the device 3 comprises a bimetallic strip 6 having a first fixed end 7 which is connected to the terminal 4 and which is made integral with the housing by any suitable means, for example by a screw 8 so as to constitute an embedding; this bimetallic strip has a second end 9 which is free and which cooperates with a transmission device 10 capable of directly or indirectly causing the opening of a safety switch 11 when the end 9 moves by a certain amount.
  • This switch is, for example placed - in series with the coil .12 of an electromagnet belonging to a contactor 14 having power switches 15 placed in the supply circuit of the current consuming device 16 (see also the block diagram in Figure 2).
  • a heater of the type with a coil of resistant wire may be associated with the bimetallic strip.
  • the device 3 uses a heater 17, which consists of a fine conductive strip or ribbon 18 made of a copper material which is a good conductor of the current (see FIGS. 3 and 4).
  • This blade has a first end 19 which is electrically connected with the terminal 4 and a second end 20 which is connected to the bimetallic strip 6, for example by electrical welding, at a particular point 21 thereof situated between the ends 7 and 9 .
  • the blade 18 extends longitudinally along a portion 36 of the bimetallic strip and is applied against a thin insulating sheet (22) which is itself placed against a first face 23 of the bimetallic strip, (see also figure 5).
  • a good thermal transfer between the blade 18 and the face 23, "through the insulating sheet 22, is provided by the pressure communicated by two multiplicity of opposite lateral tabs 24, 25 which are placed on either side of the blade 18 and which are curved in such a way that ends such as 26, 27 of each of the legs such as 28, 28 ′ come to bear, by means of the insulating sheet, on a second face 29 opposite the first face 23.
  • the insulating sheet 22 has a width sufficient to circumvent, like the legs, the opposite edges 30, 31 of the bimetal strip and also to present, under the ends of the legs, insulating portions 32, 33 of the sheet 22.
  • the heater 17 is made flat, in one piece, by cutting from a suitable metal sheet (see Figure 6), and the legs are then bent by a tool or machine studied for this purpose.
  • the first end 19 of the blade has a lateral extension 34 which is not placed opposite the bimetallic strip, this arrangement making it possible to protect the blade from deformations which could appear when the electrical connection between the heater and a conductor 35 going to terminal 4.
  • the choice of the number of legs and their width depends, on the one hand on the mechanical characteristics of the material used for the blade 18, on the forces which it is necessary to communicate to this blade to make it press well against the insulating sheet and for allow it to withstand the electro-dynamic forces that appear during short circuits and, on the other hand, precautions taken to prevent the mechanical association of the heater with the bimetallic strip from imparting parasitic rigidity to the latter.
  • the materials used for the heater will be, for example, copper or a suitable brass.
  • bimetallic strip comprising a pair of metals having very different coefficients of expansion, such as invar and an Fe - Ni - Cr alloy, or a bimetallic strip further comprising a pair of metals having very different coefficients of expansion such as those mentioned, an intermediate layer of copper or nickel, when it is necessary to reduce the inherent electrical resistance of the bimetallic strip.

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  • Thermally Actuated Switches (AREA)

Abstract

1. Detection device for excess currents (3), particularly for protection apparatus, comprising, in a case (1), on the one hand, a bimetallic strip (6) having a first fixedly embedded end (7) and a second free end (9) adapted for directly or indirectly operating a safety switch (11) which is secured in the case, and, on the other hand, an electric insulated heater (17) constituted by a thin conducting blade (18) located, with good thermal contact, along a first longitudinal face (23) of the bimetallic strip (6) by means of transverse insulated tightening means one end (20) of which is connected to a point of the bimetallic strip (6) situated between the ends in such a way that the current to be monitored flows across the heater (17) and the bimetallic strip (6), a thin insulating sheet (22) being disposed between the heater (17) and said first face (23), wherein said tightening means are constituted by a plurality (24, 25) of opposite deformable side clips (28, 28') cut in opposite regions (24, 25) of the conducting blade (18), which pass round the two edges (30, 31) of the bimetallic strip and whose ends (26, 27) bear, by means of bent portions (32, 33) of the insulating sheet (22), on a second longitudinal face (29) opposite the first face.

Description

L'invention concerne un dispositif de détection de surintensités de courant , en particulier pour un appareil de protection, comprenant dans un boîtier, d'une part, une bilame ayant une première extrémité fixe encastrée et une seconde extrémité libre qui est apte à actionner, directement ou indirectement, un interrupteur de sécurité fixé dans le boîtier et, d'autre part, une chaufferette électrique isolée qui est placée en" bon contact thermique le long de la bilame et dont une extrémité est reliée en un point de la bilame situé entre les extrémités, de façon telle que le courant à surveiller traverse la chaufferette et la bilame.The invention relates to a device for detecting current overcurrents, in particular for a protection device, comprising in a housing, on the one hand, a bimetallic strip having a first fixed fixed end and a second free end which is capable of actuating, directly or indirectly, a safety switch fixed in the housing and, on the other hand, an insulated electric heater which is placed in "good thermal contact along the bimetallic strip and one end of which is connected at a point in the bimetallic strip located between the ends, so that the current to be monitored crosses the heater and the bimetallic strip.

De tels dispositifs sont largement utilisés dans les appareils de protection, tels que les relais thermiques, dont la fonction est d'ouvrir indirectement le circuit d'alimentation d'un appareil consommateur à surveiller lorsque les intensités des courants qui le traversent dépassent, pendant un certain temps, une valeur de consigne particulière.Such devices are widely used in protective devices, such as thermal relays, the function of which is to indirectly open the supply circuit of a consumer device to be monitored when the intensities of the currents passing through it exceed, during a certain time, a particular setpoint.

Dans les dispositifs connus, on réalise généralement la chaufferette sous la forme d'un bobinage de fil résistant placé autour de la bilame.In known devices, the heater is generally produced in the form of a coil of resistant wire placed around the bimetallic strip.

Si une telle disposition présente des avantages relativement à la qualité des échanges thermiques entre la chaufferette et la bilame, ainsi qu'une bonne tenue mécanique lors de l'apparition de courants de court-circuit, on constate que son utilisation dans une large gamme de courants nominaux, fait apparaître des difficultés lorsque l'appareil de protection doit répondre à des besoins industriels particuliers,If such an arrangement has advantages relative to the quality of the heat exchanges between the heater and the bimetallic strip, as well as good mechanical strength during the appearance of short-circuit currents, it is found that its use in a wide range of nominal currents, gives rise to difficulties when the protective device has to respond to special industrial needs,

Le choix des dimensions que l'on doit donner à une bilame et à la chaufferette bobinée qui la réchauffe, serait aisé si le constructeur ne devait tenir compte que des propriétés des matériaux disponibles et des forces ou déplacements qui doivent être développés ou respectivement effectués, lorsqu'une intensité particulière traverse l'appareil.The choice of the dimensions that must be given to a bimetallic strip and to the coiled heater which heats it, would be easy if the manufacturer had to take into account only the properties of the available materials and the forces or displacements which must be developed or respectively carried out, when a particular intensity crosses the device.

En fait, la mise en oeuvre industrielle d'un tel dispositif doit tenir compte, lorsqu'il est destiné à effectuer une protection, d'une part, de la nature des surcharges que subissent les appareils consommateurs et, d'autre part, des conditions d'une fabrication économique d'appareils aptes à satisfaire plusieurs calibres de courants nominaux.In fact, the industrial implementation of such a device must take into account, when it is intended to effect protection, on the one hand, of the nature of the overloads which the consumer devices undergo and, on the other hand, of the conditions for economical manufacture of devices capable of satisfying several ratings of nominal currents.

La première condition fait que le dispositif doit présenter un temps de réponse supérieur à une valeur normalisée pour des surcharges de courant de l'ordre de six fois le courant nominal.The first condition means that the device must have a response time greater than a standardized value for current overloads of the order of six times the nominal current.

La seconde condition fait que l'appareil contenant le dispositif de protection ne doit pas avoir des dimensions trop importantes et qu'un même boîtier d'appareil de protection devra pouvoir contenir des dispositifs de protection différents pour être utilisés avec des courants d'intensités nominales différentes.The second condition means that the device containing the protective device must not be too large and that the same protective device case must be able to contain different protective devices to be used with nominal current currents. different.

D'une façon générale, on constate que, lorsque les dimensions d'une bilame sont déterminées par le choix préalable d'un type de boîtier particulier et restent constantes pour tous les calibres nominaux, la puissance calorifique nécessaire pour provoquer une déformation donnée reste sensiblement constante. Il en résulte que la résistance ohmique totale du dispositif qui comprend celle de la chaufferette et celle de la portion de bilame montée en série doit diminuer lorsque l'intensité nominale augmente. La diminution de cette résistance totale peut être elle-même obtenue soit par la diminution de la résistance de la chaufferette, soit par celle de la bilame, soit par une diminution combinée des deux résistances.In general, it can be seen that, when the dimensions of a bimetal strip are determined by the prior choice of a particular type of housing and remain constant for all nominal sizes, the calorific power necessary to cause a given deformation remains substantially constant. It follows that the total ohmic resistance of the device which includes that of the heater and that of the bimetallic strip portion connected in series must decrease when the nominal current increases. The reduction in this total resistance can itself be obtained either by the reduction in the resistance of the heater, or by that of the bimetallic strip, or by a combined reduction in the two resistances.

Par ailleurs, la valeur du rapport entre ces deux résistances influence le temps de réponse ; lorsque la puissance dissipée dans la bilame est prépondérante, le temps de réponse est plus court que dans le cas contraire ; ce temps de réponse devient également plus court lorsque la chaufferette est bobinée sur toute la longueur de la bilame ; un temps de réponse trop court peut provoquer un déclenchement prématuré de l'appareil de protection.Furthermore, the value of the ratio between these two resistances influences the response time; when the power dissipated in the bimetallic strip is preponderant, the response time is shorter than in the opposite case; this response time also becomes shorter when the heater is coiled over the entire length of the bimetallic strip; too short a response time may cause the protective device to trip prematurely.

Ces constatations conduisent donc à remarquer qu'il est très difficile de conférer à un dispositif de protection à bilame et chaufferette un comportement qui soit toujours adapté à celui de la charge, lorsque l'on souhaite protéger des appareils consommateur d'intensités nominales différentes à l'aide de bilames ayant toujours les mêmes dimensions, ou des dimensions sensiblement égales.These observations therefore lead to note that it is very difficult to give a bimetallic and heater protection device a behavior which is always adapted to that of the load, when it is desired to protect consumer devices with different nominal intensities at using bimetallic strips always having the same dimensions, or substantially equal dimensions.

On remarque notamment que, lorsque l'intensité nominale augmente, il est difficile de donner à la chaufferette et à la bilame les faibles résistances nécessaires ; cette difficulté résulte du fait que, d'une part, la longueur du fil résistant de la chaufferette devient si faible ou que son diamètre devient si important, qu'il n'est plus possible d'effectuer un bobinage convenable.We note in particular that, when the nominal current increases, it is difficult to give the heater and the bimetallic strip the low resistances necessary; this difficulty results from the fact that, on the one hand, the length of the resistant wire of the heater becomes so short or that its diameter becomes so large, that it is no longer possible to carry out a suitable winding.

Les dispositifs à bilame et chaufferette bobinée présentent toutefois l'avantage d'une bonne tenue mécanique lors de l'apparition de courants de court-circuit en raison des faibles efforts électro-dynamiques qui apparaissent entre la bilame, où la direction du courant circule longitudinalement et les spires de la chaufferette, où la direction du courant est perpendiculaire à la précédente.Bimetallic devices and coiled heater have the advantage of good mechanical strength when short-circuit currents appear due to the weak electro-dynamic forces which appear between the bimetallic strip, where the direction of the current circulates longitudinally and the turns of the heater, where the direction of the current is perpendicular to the previous one.

L'invention se propose, par suite, de fournir un dispositif à bilame et chaufferette apte à être traversé par un courant nominal important qui soit susceptible de présenter un temps de réponse répondant aux prescriptions et qui bénéficie d'une bonne résistance mécanique, lorsque la bilame qu'il utilise possède des dimensions qui ont été choisies à l'avance pour répondre à des courants nominaux inférieurs, pour lesquels une chaufferette bobinée donne toute satisfaction.The invention therefore proposes to provide a bimetallic device and heater capable of being traversed by a large nominal current which is capable of having a response time that meets the requirements and which benefits from good mechanical resistance, when the The bimetallic strip that it uses has dimensions which have been chosen in advance to meet lower nominal currents, for which a coiled heater is entirely satisfactory.

Selon l'invention, ce résultat est atteint grâce au fait que la chaufferette est constituée par une fine lame d'un matériau cuivreux, bon conducteur de courant, qui est placée longitudinalement le long d'une portion de première face longitudinale de la bilame, dont elle est séparée par une fine feuille isolante et qui est appliquée sur cette feuille par une multiplicité de pattes latérales déformables qui contournent les deux chants de la bilame et dont les extrémités s'appuient sur une seconde face longitudinale opposée à la première face.According to the invention, this result is achieved thanks to the fact that the heater consists of a thin strip of copper material, a good current conductor, which is placed longitudinally along a portion of the first longitudinal face of the bimetallic strip, from which it is separated by a thin insulating sheet and which is applied to this sheet by a multiplicity of deformable lateral tabs which bypass the two edges of the bimetallic strip and the ends of which rest on a second longitudinal face opposite the first face.

On connaît, par ailleurs, des dispositifs de détection de surintensités de courant faisant appel à une bilame à chauffage indirect dans laquelle la chaufferette est constituée par une fine lame de cuivre isolée qui est appliquée sur toute la longueur de la bilame et qui est maintenue en place par une pluralité d'agrafes placées transversalement par rapport à l'axe longitudinal.There are also known devices for detecting current overcurrents using an indirectly heated bimetallic strip in which the heater consists of a thin insulated copper strip which is applied over the entire length of the bimetallic strip and which is held in place. place by a plurality of staples placed transversely to the longitudinal axis.

Un tel dispositif ne permet pas une adaptation aisée du temps de réponse dans la mesure où l'on ne peut pas alors bénéficier de la rapidité de déformation procurée par une bilame qui s'échauffe directement dans sa masse ; par ailleurs, la nécessité de replier la lame de cuivre pour localiser l'entrée et la sortie de courant au voisinage de la racine de la bilame ne procure pas un bon rendement thermique et nécessite l'utilisation de deux pièces de raccordement électrique au lieu d'une.Such a device does not allow an easy adaptation of the response time insofar as one cannot then benefit from the speed of deformation provided by a bimetallic strip which heats up directly in its mass; by elsewhere, the need to fold the copper strip to locate the current input and output in the vicinity of the bimetal root does not provide good thermal efficiency and requires the use of two electrical connection parts instead of a.

L'invention, ainsi que d'autres mesures qui la complètent, seront mieux comprises à l'aide de la description détaillée ci-après.The invention, as well as other measures which complement it, will be better understood with the aid of the detailed description below.

Au dessin annexé :

  • La figure 1 montre une coupe locale d'un appareil de protection utilisant le dispositif selon l'invention ;
  • La figure 2 montre un schéma de principe du raccordement électrique et de la fonction d'un dispositif détecteur selon l'invention ;
  • La figure 3 représente une vue avant d'un dispositif détecteur ;
  • La figure 4 représente une vue arrière du dispositif de la figure 3 ;
  • La figure 5 illustre une vue du dispositif détecteur coupé par un plan QQ' de la figure 3; et
  • La figure 6 montre une vue de la chaufferette de l'appareil détecteur avant montage sur la bilame.
In the attached drawing:
  • Figure 1 shows a local section of a protective device using the device according to the invention;
  • Figure 2 shows a block diagram of the electrical connection and the function of a detector device according to the invention;
  • Figure 3 shows a front view of a detector device;
  • Figure 4 shows a rear view of the device of Figure 3;
  • FIG. 5 illustrates a view of the detector device cut by a plane QQ 'in FIG. 3; and
  • Figure 6 shows a view of the heater of the detector device before mounting on the bimetallic strip.

Un appareil de protection, visible à la figure 1, comporte un boîtier 1 présentant une multiplicité de logements de Longueur donnée m tels que 2, dans chacun desquels est disposé un dispositif détecteur de surintensités de cou- rant 3 ; ce boîtier qui peut contenir d'autres organes a été volontairement limité en dimensions sur la figure. Chaque dispositif tel que 3 est connecté, d'une part, à une borne d'entrée de courant 4 reliée à une phase R d'un réseau d'alimentation et, d'autre part, directement ou non à une borne de sortie de courant 5 qui est reliée par un conducteur à une borne correspondante d'un appareil consommateur de courant, non représenté.A protective device, visible in FIG. 1, comprises a box 1 having a multiplicity of housings of given length m such as 2, in each of which is disposed a device for detecting overcurrents 3; this box which can contain other organs has been deliberately limited in size in the figure. Each device such as 3 is connected, on the one hand, to a current input terminal 4 connected to a phase R of a supply network and, on the other hand, directly or not to a current output terminal 5 which is connected by a conductor to a corresponding terminal of a current consuming device, not shown.

Le dispositif 3 comprend une bilame 6 ayant une première extrémité fixe 7 qui est reliée à la borne 4 et qui est rendue solidaire du boîtier par tout moyen approprié par exemple par une vis 8 de façon à constituer un encastrement ; cette bilame possède une seconde extrémité 9 qui est libre et qui coopère avec un dispositif de transmission 10 apte à provoquer directement ou indirectement l'ouverture d'un interrupteur de sécurité 11 lorsque l'extrémité 9 se déplace d'une certaine quantité. Cet interrupteur est, par exemple placé -en série avec la bobine .12 d'un électro-aimant appartenant à un contacteur 14 ayant des interrupteurs de puissance 15 placés dans le circuit d'alimentation de l'appareil consommateur de courant 16 (voir également le schéma de principe à la figure 2).The device 3 comprises a bimetallic strip 6 having a first fixed end 7 which is connected to the terminal 4 and which is made integral with the housing by any suitable means, for example by a screw 8 so as to constitute an embedding; this bimetallic strip has a second end 9 which is free and which cooperates with a transmission device 10 capable of directly or indirectly causing the opening of a safety switch 11 when the end 9 moves by a certain amount. This switch is, for example placed - in series with the coil .12 of an electromagnet belonging to a contactor 14 having power switches 15 placed in the supply circuit of the current consuming device 16 (see also the block diagram in Figure 2).

Lorsque le même boîtier 1 est utilisé en fabrication pour recevoir divers dispositifs de détection de courant ayant des caractéristiques adaptées à divers calibres de courants nominaux imposés par la puissance consommée par la charge, on est conduit à utiliser des bilames dont la longueur P voisine de m sera toujours sensiblement la même, de façon à pouvoir utiliser le même point d'encastrement 13 et à présenter toujours son extrémité libre 9 en regard du dispositif de transmission 10 qui conserve la même position dans le boîtier.When the same box 1 is used in manufacturing to receive various current detection devices having characteristics adapted to various ratings of nominal currents imposed by the power consumed by the load, one is led to use bimetallic strips whose length P close to m will always be substantially the same, so as to be able to use the same embedding point 13 and always to present its free end 9 opposite the transmission device 10 which retains the same position in the housing.

Pour des calibres nominaux de courant inférieurs, une chaufferette du type à bobine de fil résistant pourra être associée à la bilame.For lower nominal current ratings, a heater of the type with a coil of resistant wire may be associated with the bimetallic strip.

Pour un ou plusieurs calibres de courant supérieurs, le dispositif 3 fait appel à une chaufferette 17, qui est constituée par une fine lame conductrice ou ruban 18 réalisée en un matériau cuivreux bon conducteur du courant (voir figures 3 et 4). Cette lame possède une première extrémité 19 qui est électriquement connectée avec la borne 4 et une seconde extrémité 20 qui est reliée à la bilame 6, par exemple par soudure électrique, en un point particulier 21 de celle-ci situé entre les extrémités 7 et 9.For one or more higher current ratings, the device 3 uses a heater 17, which consists of a fine conductive strip or ribbon 18 made of a copper material which is a good conductor of the current (see FIGS. 3 and 4). This blade has a first end 19 which is electrically connected with the terminal 4 and a second end 20 which is connected to the bimetallic strip 6, for example by electrical welding, at a particular point 21 thereof situated between the ends 7 and 9 .

Entre ses deux extrémités 19, 20, la lame 18 s'étend longitudinalement le long d'une portion 36 de la bilame et s'applique contre une feuille isolante mince (22) qui est elle-même placée contre une première face 23 de la bilame, (voir aussi figure 5). Un bon transfert thermique entre la lame 18 et la face 23,"à travers la feuille isolante 22, est procuré grâce à la pression communiquée par deux multiplicités de pattes latérales opposées 24, 25 qui sont placées de part et d'autre de la lame 18 et qui sont recourbées de façon telle, que des extrémités telles que 26, 27 de chacune des pattes telles que 28, 28' viennent s'appuyer, par l'intermédiaire de la feuille isolante, sur une seconde face 29 opposée à la première face 23. La feuille isolante 22 possède une largeur suffisante pour contourner, comme les pattes, les chants opposés 30, 31 de la bilame et pour présenter également sous les extrémités des pattes, des portions isolantes 32, 33 de la feuille 22. La chaufferette 17 est fabriquée à plat, d'une seule pièce, par découpage dans une feuille de métal approprié (voir figure 6), et les pattes sont ensuite recourbées par un outil ou machine étudiés à cet effet.Between its two ends 19, 20, the blade 18 extends longitudinally along a portion 36 of the bimetallic strip and is applied against a thin insulating sheet (22) which is itself placed against a first face 23 of the bimetallic strip, (see also figure 5). A good thermal transfer between the blade 18 and the face 23, "through the insulating sheet 22, is provided by the pressure communicated by two multiplicity of opposite lateral tabs 24, 25 which are placed on either side of the blade 18 and which are curved in such a way that ends such as 26, 27 of each of the legs such as 28, 28 ′ come to bear, by means of the insulating sheet, on a second face 29 opposite the first face 23. The insulating sheet 22 has a width sufficient to circumvent, like the legs, the opposite edges 30, 31 of the bimetal strip and also to present, under the ends of the legs, insulating portions 32, 33 of the sheet 22. The heater 17 is made flat, in one piece, by cutting from a suitable metal sheet (see Figure 6), and the legs are then bent by a tool or machine studied for this purpose.

On remarquera aux figures 1 et 3 que, la première extrémité 19 de la lame comporte un prolongement latéral 34 qui n'est pas placé en regard de la bilame, cette disposition permettant de mettre la lame à l'abri des déformations qui pourraient apparaître lorsque l'on réalise, par exemple par soudure, la connection électrique entre la chaufferette et un conducteur 35 allant vers la borne 4.It will be noted in FIGS. 1 and 3 that the first end 19 of the blade has a lateral extension 34 which is not placed opposite the bimetallic strip, this arrangement making it possible to protect the blade from deformations which could appear when the electrical connection between the heater and a conductor 35 going to terminal 4.

Le choix du nombre de pattes et de leur largeur dépend, d'une part des caractéristiques mécaniques du matériau utilisé pour la lame 18, des efforts qu'il est nécessaire de communiquer à cette lame pour la faire bien plaquer contre la feuille isolante et pour lui permettre de supporter les efforts électro-dynamiques qui apparaissent lors de courts- circuits et, d'autre part, de précautions prises pour éviter que l'association mécanique de la chaufferette avec la bilame ne communique à celle-ci une rigidité parasite. Les matériaux utilisés pour la chaufferette seront, par exemple, le cuivre ou un laiton approprié.The choice of the number of legs and their width depends, on the one hand on the mechanical characteristics of the material used for the blade 18, on the forces which it is necessary to communicate to this blade to make it press well against the insulating sheet and for allow it to withstand the electro-dynamic forces that appear during short circuits and, on the other hand, precautions taken to prevent the mechanical association of the heater with the bimetallic strip from imparting parasitic rigidity to the latter. The materials used for the heater will be, for example, copper or a suitable brass.

Pour adapter les caractéristiques du dispositif, on peut faire appel, soit à une bilame comprenant un couple de métaux'ayant des coefficients de dilatation très différents, tels que l'invar et un alliage Fe - Ni - Cr, soit à une bilame comprenant outre un couple de métaux ayant des coefficients de dilatation très différents tels que ceux mentionnés, une couche intermédiaire de cuivre ou de nickel, lorsqu'il est nécessaire de diminuer la résistance électrique propre de la bilame.To adapt the characteristics of the device, it is possible to use either a bimetallic strip comprising a pair of metals having very different coefficients of expansion, such as invar and an Fe - Ni - Cr alloy, or a bimetallic strip further comprising a pair of metals having very different coefficients of expansion such as those mentioned, an intermediate layer of copper or nickel, when it is necessary to reduce the inherent electrical resistance of the bimetallic strip.

Claims (2)

1. Dispositif de détection de surintensités de courant, en particulier pour appareil de protection, compr.enant, dans un boîtier, d'une part une bilame ayant une première extrémité fixe encastrée et une seconde extrémité libre qui est apte à actionner directement ou indirectement un interrupteur de sécurité fixé dans le boîtier et, d'autre part, une chaufferette électrique isolée constituée par une fine lame conductrice, qui est placée en bon contact thermique le long d'une première face longitudinale de la bilame à l'aide d'organes de serrage transversaux isolés et dont une extrémité est reliée en un point de la bilame situé entre les extrémités, de façon telle que le courant à surveiller traverse la chaufferette et la bilame, une fine feuille isolante étant disposée entre la chaufferette et ladite première face,
caractérisé en ce que lesdits organes de serrage sont constitués par une multiplicité (24, 25) de pattes latérales déformables opposées (28, 28'), qui sont découpées dans des régions opposées (24, 25) de la lame conductrice (18), qui contournent les deux chants (30, 31) de la bilame, et dont les extrémités (26, 27) s'appuient, par l'intermédiaire de portions repliées (32, 33) de la feuille isolante (22), sur une seconde face longitudinale (29) opposée à la première face.
1. Device for detecting current overcurrents, in particular for a protective device, comprising, in a housing, on the one hand a bimetallic strip having a fixed fixed first end and a second free end which is capable of actuating directly or indirectly a safety switch fixed in the housing and, on the other hand, an insulated electric heater constituted by a fine conductive strip, which is placed in good thermal contact along a first longitudinal face of the bimetallic strip using insulated transverse clamping members, one end of which is connected at a point of the bimetallic strip situated between the ends, so that the current to be monitored passes through the heater and the bimetallic strip, a thin insulating sheet being placed between the heater and said first face ,
characterized in that said clamping members consist of a multiplicity (24, 25) of opposite deformable lateral tabs (28, 28 '), which are cut out in opposite regions (24, 25) of the conductive blade (18), which bypass the two edges (30, 31) of the bimetallic strip, and whose ends (26, 27) are supported, by means of folded portions (32, 33) of the insulating sheet (22), on a second longitudinal face (29) opposite the first face.
2. Dispositif de détection de surintensité selon la revendication 1,
caractérisé en ce que la bilame (6) comporte, outre deux métaux ayant des coefficients de dilatation très différents, une couche de cuivre ou de nickel.
2. Overcurrent detection device according to claim 1,
characterized in that the bimetallic strip (6) comprises, in addition to two metals having very different coefficients of expansion, a layer of copper or nickel.
EP19820402022 1981-11-09 1982-11-03 Bi-metal device connected in series to a heater Expired EP0080393B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8120921A FR2516301A1 (en) 1981-11-09 1981-11-09 BILAMETER DEVICE PLACED IN SERIES WITH A HEATER
FR8120921 1981-11-09

Publications (2)

Publication Number Publication Date
EP0080393A1 true EP0080393A1 (en) 1983-06-01
EP0080393B1 EP0080393B1 (en) 1985-04-03

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ID=9263814

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820402022 Expired EP0080393B1 (en) 1981-11-09 1982-11-03 Bi-metal device connected in series to a heater

Country Status (3)

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EP (1) EP0080393B1 (en)
DE (1) DE3262898D1 (en)
FR (1) FR2516301A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0514931A3 (en) * 1991-05-24 1993-10-06 Matsushita Electric Industrial Co., Ltd. A thermal protector
DE4406377A1 (en) * 1994-02-26 1995-08-31 Abb Patent Gmbh Arrangement for heating thermo-bimetallic strip, shape memory alloy or similar
DE19610106A1 (en) * 1996-03-15 1997-09-18 Holzschuh Gmbh & Co Kg Remote control of vehicle heating and ventilation electric fan motor

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB332714A (en) * 1929-06-28 1930-07-31 Felten & Guilleaume Carlswerk Improvements in and relating to bi-metal releasing devices
FR714871A (en) * 1930-03-18 1931-11-21 Thomson Houston Comp Francaise Improvements to thermal relays and their heating devices
DE738071C (en) * 1941-10-15 1943-08-02 Siemens Ag Thermal release for electrical switches
DE1053640B (en) * 1954-06-12 1959-03-26 Ellenberger & Poensgen Overcurrent protection switch
DE1059552B (en) * 1956-08-16 1959-06-18 Stotz Kontakt Gmbh Circuit breaker for alternating current
DE1513256A1 (en) * 1965-03-16 1969-10-16 Licentia Gmbh Bimetal device, in particular bimetal release
DE2818203A1 (en) * 1978-04-26 1979-11-08 Bbc Brown Boveri & Cie Thermal switching device with bimetal strip - has heater placed on bimetal strip, separated by insulating foil and held in position clip

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE560551C (en) * 1929-06-25 1932-10-05 Felten & Guilleaume Carlswerk Bi-metal release with shunt

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB332714A (en) * 1929-06-28 1930-07-31 Felten & Guilleaume Carlswerk Improvements in and relating to bi-metal releasing devices
FR714871A (en) * 1930-03-18 1931-11-21 Thomson Houston Comp Francaise Improvements to thermal relays and their heating devices
DE738071C (en) * 1941-10-15 1943-08-02 Siemens Ag Thermal release for electrical switches
DE1053640B (en) * 1954-06-12 1959-03-26 Ellenberger & Poensgen Overcurrent protection switch
DE1059552B (en) * 1956-08-16 1959-06-18 Stotz Kontakt Gmbh Circuit breaker for alternating current
DE1513256A1 (en) * 1965-03-16 1969-10-16 Licentia Gmbh Bimetal device, in particular bimetal release
DE2818203A1 (en) * 1978-04-26 1979-11-08 Bbc Brown Boveri & Cie Thermal switching device with bimetal strip - has heater placed on bimetal strip, separated by insulating foil and held in position clip

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0514931A3 (en) * 1991-05-24 1993-10-06 Matsushita Electric Industrial Co., Ltd. A thermal protector
DE4406377A1 (en) * 1994-02-26 1995-08-31 Abb Patent Gmbh Arrangement for heating thermo-bimetallic strip, shape memory alloy or similar
DE19610106A1 (en) * 1996-03-15 1997-09-18 Holzschuh Gmbh & Co Kg Remote control of vehicle heating and ventilation electric fan motor

Also Published As

Publication number Publication date
FR2516301A1 (en) 1983-05-13
DE3262898D1 (en) 1985-05-09
EP0080393B1 (en) 1985-04-03
FR2516301B1 (en) 1984-11-30

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