EP0287423B1 - Method for rigidly attaching a metal piece to a thermoplastic support, and a metal-thermoplastic electric contact - Google Patents

Method for rigidly attaching a metal piece to a thermoplastic support, and a metal-thermoplastic electric contact Download PDF

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Publication number
EP0287423B1
EP0287423B1 EP19880400782 EP88400782A EP0287423B1 EP 0287423 B1 EP0287423 B1 EP 0287423B1 EP 19880400782 EP19880400782 EP 19880400782 EP 88400782 A EP88400782 A EP 88400782A EP 0287423 B1 EP0287423 B1 EP 0287423B1
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EP
European Patent Office
Prior art keywords
metal part
thermoplastic
process according
thermoplastic support
recess
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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.)
Expired - Lifetime
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EP19880400782
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German (de)
French (fr)
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EP0287423A1 (en
Inventor
Pierre Vincent
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Merlin Gerin SA
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Merlin Gerin SA
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Publication of EP0287423A1 publication Critical patent/EP0287423A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/40—Securing contact members in or to a base or case; Insulating of contact members
    • H01R13/405—Securing in non-demountable manner, e.g. moulding, riveting
    • H01R13/41—Securing in non-demountable manner, e.g. moulding, riveting by frictional grip in grommet, panel or base
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/58—Electric connections to or between contacts; Terminals
    • H01H1/5822—Flexible connections between movable contact and terminal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/02—Details
    • H01H73/04—Contacts

Definitions

  • the invention relates to a method of rigid fixing of a flattened metal part on a thermoplastic support, in particular of a low voltage electrical contact on a plastic contact arm, in which the thermoplastic support has an insertion notch flat and without play at the end of the metal part.
  • the known fixing methods use either bonding or overmolding, or ultrasonic welding.
  • the handling of glues and adhesives is delicate and it requires complicated and expensive installations.
  • Overmolding requires special molds allowing the introduction of the metal part inside the mold, which complicates the molding operation of the thermoplastic part.
  • Welding using ultrasound generates vibrations which are detrimental to neighboring parts and to surface conditions.
  • the present invention relates to a rigid fixing method using standard tools and ensuring perfect positioning of the two parts.
  • the fixing method according to the invention comprises the following steps; the thermoplastic support is placed with the metal part inserted in the notch on a resistance welding machine, one of the electrodes of which is in contact with the metal part, the metal part is heated by passing an electric current through it embedded in the thermoplastic support by causing a local supercooling of the thermoplastic material and a pressure is maintained to maintain the part metal in the notch on the metal part during the heating operation to cause a rise in the molten thermoplastic material and an encrustation.
  • the supercooling of the thermoplastic material is obtained by heating the metal part by Joule effect using a resistance welding machine. This supercooling is controlled by adjusting the amplitude of the current and the passage time through the metal part and possibly by the clamping pressure of the two parts. It is also possible to use a capacitive discharge welder.
  • the very good mechanical connection between the two parts is obtained by the localized melting of the thermoplastic material over the entire periphery of the metal part inserted in the notch.
  • the slight penetration of the metal part into the thermoplastic support causes a rise in the molten thermoplastic which clogs all the interstices between the metal part and the notch to obtain an assembly comparable to an overmolding.
  • the two parts can be perfectly positioned relative to each other on the welding machine, for example using shims or clamping cylinders, prior to the fixing or welding operation.
  • Document US-A-3,497.952 relates to the fixing of a contact in a plastic block.
  • One end of the contact has bosses and cavities, and this end is force fitted into an orifice so as to compress the plastic material confining the orifice.
  • induction heating the contact the internal tensions in the plastic are reduced and the softened plastic enters the cavities to strengthen the anchoring.
  • the inlaying operation is combined with the welding of a conductor on the metal part, this welding being carried out by the weld during the heating of the metal part carrying out the incrustation.
  • the electrical conductor can be a flexible connection braid.
  • the welding of this braid is carried out by applying the end to be welded to the free face of the metal part by inserting it between this part and the welding electrode.
  • contact pads having a low resistivity and a high resistance to erosion, such as molybdenum or tungsten carbonate.
  • the fixing method according to the invention can be easily automated and the fixing is final at the end of the welding operation.
  • the invention also relates to an electrical contact manufactured according to the inventive method, this contact being for example, the movable contact of a low voltage electric circuit breaker.
  • the thermoplastic support has the advantage of an electrical insulation of the electrical contact and an ease of choice of shapes due to the molding of this thermoplastic part.
  • an electrical contact 10 in particular the movable contact of an electrical circuit breaker, consists of a support 12 made of a molded thermoplastic material and a metal part 14.
  • the metal part 14 of flattened and elongated shape is assembled by the one 16 of its ends to the thermoplastic support 12 while the opposite end 18 carries a contact pad 20 capable of cooperating with a fixed contact in the closed position of the breaking device.
  • the electrical contact 10 is pivotally mounted on an axis 22 passing perpendicularly through the thermoplastic support 12 of flattened and elongated shape.
  • To the metal part 14 is welded a braid 24 for electrical connection.
  • the metal part 14 extends in the extension of the thermoplastic support 12 and its end 16 is inserted into a notch 26 formed in the support 12.
  • the metal part 14 is fixed to the thermoplastic support 12 according to the invention by heating the metal part 14 so as to cause an overcooling of the thermoplastic material and an inlay of the metal part 14 in the notch 26.
  • This operation is made on a welding machine, schematically shown in Figure 2, the thermoplastic support 12 with the metal part 14 inserted in the notch 26 being placed on a lower electrode 28 of the welding machine.
  • the support 12 is placed flat on the face of the electrode 28, the notch 26 with the metal part 14 being oriented upwards in the direction of the upper electrode 30 of the welding machine.
  • the lower electrode 28 carries a contact pad 32 projecting from the face of the electrode 28 to carry the end 18 of the metal piece 14.
  • the height of the pad 32 compensates for the offset between the support 12 and the metal piece 14.
  • the metal part 14 is held in mechanical and electrical contact with the pad 32 by a clamping system, schematically represented by an arm 34 of a jack which presses on the upper face of the metal piece 14 opposite the pad 32
  • the upper electrode 30 carries a contact pad 36 brought into contact with the end 16 of the metal part 14.
  • the thickness of the metal part 14 is slightly greater than the depth of the notch 26 to produce a slight projection of the part 14, on which the pad 36 is applied for the welding operation.
  • the welding operation is carried out by bringing the electrodes 28, 30 together, and by passing the current from the electrode 30 through the patch 36, the metal part 14 and the patch 32.
  • the Joule effect heating of the metal part 14 causes a local melting of the thermoplastic material in contact with the metal part 14, and an inlay of the end 16 of the metal part 14 in the notch 26.
  • This inlay can be accompanied by a slight penetration into the notch 26 bringing the metal part flush with the thermoplastic support 12 or possibly with slight shrinkage, if care is taken to use a patch 36 of dimension smaller than that of the notch 26, to maintain the electrical contact with the metal part 14.
  • the heating time and the pressure applied by the electrodes 28.30 are determined depending on the nature of the materials to be assembled.
  • the welding operation does not modify the relative positioning of the support 12 and of the metal part 14, this positioning being carried out by any appropriate means, in particular by wedges or imprints made on the electrodes 28, 30.
  • the small clearance provided between the metal part 14 and the notch 26 compensates for manufacturing inaccuracies, additional compensation being able to result from the plasticity of the support 12.
  • the shape of the notch 26 is of course combined with that of the end 16 of the metal part 14 for fixing on all of the faces of the end 16 housed in the notch 26.
  • the braid 24 is fixed to the metal part 14 can be carried out during a following welding operation on the same machine or on another machine, but according to the invention, this welding operation is carried out simultaneously by inserting the end 38 of the braid 24 between the pad 36 of the upper electrode 30 and the end 16 of the metal part 14.
  • the pad 36 of the upper electrode 30 is applied to the end 38 of the braid 24 and during the passage of the current welds this end 38 on the metal part 14 in the usual manner.
  • the end 38 can of course have been tinned beforehand.
  • the use of the same machine and the simultaneous production of the braid 24 and the fixing of the metal part 14 on the thermoplastic support 12, allow an appreciable saving in cost and manufacturing time.
  • the electrical contact 10 is ready to be mounted in the electrical appliance and does not require any further treatment, in particular cleaning or rectification.
  • the invention is of course in no way limited to the manufacture an electrical contact and it can be used for any attachment of a metal part to a part made of a thermoplastic material.

Description

L'invention est relative à un procédé de fixation rigide d'une pièce métallique aplatie sur un support thermoplastique, notamment d'un contact électrique basse tension sur un bras de contact en matière plastique, dans lequel le support thermoplastique présente une encoche d'insertion à plat et sans jeu de l'extrémité de la pièce métallique.The invention relates to a method of rigid fixing of a flattened metal part on a thermoplastic support, in particular of a low voltage electrical contact on a plastic contact arm, in which the thermoplastic support has an insertion notch flat and without play at the end of the metal part.

Pour allier les avantages des pièces métalliques, notamment de solidité et de conduction électrique avec ceux des pièces thermoplastiques, notamment d'isolation électrique et de facilité de moulage, on a été amené à créer des assemblages rigides pour constituer une pièce monobloc en métal et en thermoplastique. Les procédés connus de fixation font appel soit au collage ou surmoulage, soit à la soudure aux ultra sons. La manipulation des colles et des adhésifs est délicate et elle nécessite des installations compliquées et coûteuses. Le surmoulage nécessite des moules spéciaux permettant l'introduction de la pièce métallique à l'intérieur du moule, ce qui complique l'opération de moulage de la pièce thermoplastique. La soudure aux ultra sons engendre des vibrations préjudiciables aux pièces voisines et aux états des surfaces. La présente invention a pour objet un procédé de fixation rigide utilisant des outils standards et assurant un positionnement parfait des deux pièces.To combine the advantages of metal parts, in particular of solidity and electrical conduction with those of thermoplastic parts, in particular of electrical insulation and ease of molding, we have been led to create rigid assemblies to constitute a single piece of metal and thermoplastic. The known fixing methods use either bonding or overmolding, or ultrasonic welding. The handling of glues and adhesives is delicate and it requires complicated and expensive installations. Overmolding requires special molds allowing the introduction of the metal part inside the mold, which complicates the molding operation of the thermoplastic part. Welding using ultrasound generates vibrations which are detrimental to neighboring parts and to surface conditions. The present invention relates to a rigid fixing method using standard tools and ensuring perfect positioning of the two parts.

Le procédé de fixation selon l'invention comprend les étapes suivantes; on dispose le support thermoplastique avec la pièce métallique insérée dans l'encoche sur une machine à souder par résistance dont l'une des électrodes est au contact de la pièce métallique, on chauffe la pièce métallique par passage d'un courant électrique pour l'incruster dans le support thermoplastique en provoquant une surfusion locale du matériau thermoplastique et on exerce une pression de maintien de la pièce métallique dans l'encoche sur la pièce métallique pendant l'opération de chauffage pour provoquer une remontée du matériau thermoplastique en fusion et une incrustation.The fixing method according to the invention comprises the following steps; the thermoplastic support is placed with the metal part inserted in the notch on a resistance welding machine, one of the electrodes of which is in contact with the metal part, the metal part is heated by passing an electric current through it embedded in the thermoplastic support by causing a local supercooling of the thermoplastic material and a pressure is maintained to maintain the part metal in the notch on the metal part during the heating operation to cause a rise in the molten thermoplastic material and an encrustation.

La surfusion du matériau thermoplastique est obtenue en chauffant par effet Joule, la pièce métallique à l'aide d'une machine à souder par résistance. Cette surfusion est maîtrisée par le règlage de l'amplitude du courant et du temps de passage à travers la pièce métallique et éventuellement par la pression de serrage des deux pièces. Il est également possible d'utiliser une soudeuse à décharge capacitive. La très bonne liaison mécanique entre les deux pièces est obtenue grâce à la fusion localisée du matériau thermoplastique sur toute la périphérie de la pièce métallique insérée dans l'encoche. La légère pénétration de la pièce métallique dans le support thermoplastique provoque une remontée du thermoplastique en fusion qui colmate tous les interstices entre la pièce métallique et l'encoche pour obtenir un assemblage comparable à un surmoulage. Les deux pièces peuvent être parfaitement positionées l'une par rapport à l'autre sur la machine à souder, par exemple à l'aide de cales ou de vérins de serrage, préalablement à l'opération de fixation ou de soudage.The supercooling of the thermoplastic material is obtained by heating the metal part by Joule effect using a resistance welding machine. This supercooling is controlled by adjusting the amplitude of the current and the passage time through the metal part and possibly by the clamping pressure of the two parts. It is also possible to use a capacitive discharge welder. The very good mechanical connection between the two parts is obtained by the localized melting of the thermoplastic material over the entire periphery of the metal part inserted in the notch. The slight penetration of the metal part into the thermoplastic support causes a rise in the molten thermoplastic which clogs all the interstices between the metal part and the notch to obtain an assembly comparable to an overmolding. The two parts can be perfectly positioned relative to each other on the welding machine, for example using shims or clamping cylinders, prior to the fixing or welding operation.

Le document US-A-3.497.952 concerne la fixation d'un contact dans un bloc en matière plastique. Une extrémité du contact présente des bossages et des cavités, et cette extrémité est emmanchée de force dans un orifice de façon à comprimer la matière plastique confinant l'orifice. En chauffant par induction le contact, les tensions internes à la matière plastique sont réduites et la matière plastique ramollie pénètre dans les cavités pour renforcer l'ancrage.Document US-A-3,497.952 relates to the fixing of a contact in a plastic block. One end of the contact has bosses and cavities, and this end is force fitted into an orifice so as to compress the plastic material confining the orifice. By induction heating the contact, the internal tensions in the plastic are reduced and the softened plastic enters the cavities to strengthen the anchoring.

Selon un développemnt important de l'invention, l'opération d'incrustation est combinée au soudage d'un conducteur sur la pièce métallique, ce soudage étant réalisé par la machine à souder pendant le chauffage de la pièce métallique réalisant l'incrustation. Dans l'application préférentielle du procédé selon l'invention à la fabrication de contacts électriques, notamment des contacts mobiles d'appareils de coupure de courant basse tension, le conducteur électrique peut être une tresse souple de connexion. Le soudage de cette tresse est réalisé en appliquant l'extrémité à souder sur la face libre de la pièce métallique en l'insérant entre cette pièce et l'électrode de soudage. Pour améliorer la qualité du contact électrique entre les électrodes de la machine à souder et la pièce métallique, il est avantageux d'utiliser des pastilles de contact ayant une faible résistivité et une forte tenue à l'érosion telles que des pastilles en molybdène ou en carbure de tungstène. Le procédé de fixation selon l'invention peut être facilement automatisé et la fixation est définitive dès la fin de l'opération de soudage.According to an important development of the invention, the inlaying operation is combined with the welding of a conductor on the metal part, this welding being carried out by the weld during the heating of the metal part carrying out the incrustation. In the preferred application of the method according to the invention to the manufacture of electrical contacts, in particular movable contacts of low voltage current cut-off devices, the electrical conductor can be a flexible connection braid. The welding of this braid is carried out by applying the end to be welded to the free face of the metal part by inserting it between this part and the welding electrode. To improve the quality of the electrical contact between the electrodes of the welding machine and the metal part, it is advantageous to use contact pads having a low resistivity and a high resistance to erosion, such as molybdenum or tungsten carbonate. The fixing method according to the invention can be easily automated and the fixing is final at the end of the welding operation.

L'invention est également relative à un contact électrique fabriqué selon le procédé inventif, ce contact étant par exemple, le contact mobile d'un disjoncteur électrique basse tension. Le support thermoplastique présente l'avantage d'une isolation électrique du contact électrique et une facilité de choix des formes due au moulage de cette pièce thermoplastique.The invention also relates to an electrical contact manufactured according to the inventive method, this contact being for example, the movable contact of a low voltage electric circuit breaker. The thermoplastic support has the advantage of an electrical insulation of the electrical contact and an ease of choice of shapes due to the molding of this thermoplastic part.

D'autres avantages et caractéristiques ressortiront plus clairement de la description qui va suivre d'un mode de mise en oeuvre de l'invention donné à titre d'exemple non limitatif et représenté aux dessins annexés dans lesquels:

  • la figure 1 est une vue schématique en plan d'un contact électrique selon l'invention;
  • la figure 2 est une vue en élévation de la machine à souder pendant la phase de soudage du contact selon la figure 1;
  • la figure 3 est une vue de côté du contact selon la figure 1;
  • la figure 4 est une vue analogue à celle de la figure 3 montrant les pièces avant leur assemblage, le support thermoplastique étant représenté en coupe.
Other advantages and characteristics will emerge more clearly from the description which follows of an embodiment of the invention given by way of nonlimiting example and represented in the appended drawings in which:
  • Figure 1 is a schematic plan view of an electrical contact according to the invention;
  • Figure 2 is an elevational view of the welding machine during the contact welding phase according to Figure 1;
  • Figure 3 is a side view of the contact according to Figure 1;
  • Figure 4 is a view similar to that of Figure 3 showing the parts before their assembly, the thermoplastic support being shown in section.

Sur les figures, un contact électrique 10, notamment le contact mobile d'un disjoncteur électrique, est constitué par un support 12 en un matériau thermoplastique moulé et une pièce métallique 14. La pièce métallique 14 de forme aplatie et allongée est assemblée par l'une 16 de ses extrémités au support thermoplastique 12 tandis que l'extrémité opposée 18 porte une pastille de contact 20 susceptible de coopérer avec un contact fixe en position de fermeture de l'appareil de coupure. Le contact électrique 10 est monté à pivotement sur un axe 22 traversant perpendiculairement le support thermoplastique 12 de forme aplatie et allongée. A la pièce métallique 14 est soudée une tresse 24 de connexion électrique. La pièce métallique 14 s'étend dans le prolongement du support thermoplastique 12 et son extrémité 16 est insérée dans une encoche 26 ménagée dans le support 12. Un tel contact électrique est bien connu en soi, et il est inutile de le décrire plus en détail. La fixation de la pièce métallique 14 sur le support thermoplastique 12 est réalisée selon l'invention par chauffage de la pièce métallique 14 de manière à provoquer une surfusion du matériau thermoplastique et une incrustation de la pièce métallique 14 dans l'encoche 26. Cette opération est réalisée sur une machine à souder, schématiquement représentée sur la figure 2, le support thermoplastique 12 avec la pièce métallique 14 insérée dans l'encoche 26 étant placé sur une électrode inférieure 28 de la machine à souder. Le support 12 est posé à plat sur la face de l'électrode 28, l'encoche 26 avec la pièce métallique 14 étant orientée vers le haut en direction de l'électrode supérieure 30 de la machine à souder. L'électrode inférieure 28 porte une pastille de contact 32 faisant saillie de la face de l'électrode 28 pour porter l'extrémité 18 de la pièce métallique 14. La hauteur de la pastille 32 compense le décalage entre le support 12 et la pièce métallique 14. La pièce métallique 14 est maintenue au contact mécanique et électrique de la pastille 32 par un système de serrage, schématiquement représenté par un bras 34 d'un vérin qui appuie sur la face supérieure de la pièce métallique 14 en regard de la pastille 32. L'électrode supérieure 30 porte une pastille de contact 36 amenée au contact de l'extrémité 16 de la pièce métallique 14. L'épaisseur de la pièce métallique 14 est légèrement supérieure à la profondeur de l'encoche 26 pour réaliser une faible saillie de la pièce 14, sur laquelle vient s'appliquer la pastille 36 pour l'opération de soudage. L'opération de soudage est réalisée par rapprochement des électrodes 28,30, et par passage du courant de l'électrode 30 à travers la pastille 36, la pièce métallique 14 et la pastille 32. L'échauffement par effet Joule de la pièce métallique 14 provoque une fusion locale du matériau thermoplastique au contact de la pièce métallique 14, et une incrustation de l'extrémité 16 de la pièce métallique 14 dans l'encoche 26. Cette incrustation peut s'accompagner d'une légère pénétration dans l'encoche 26 amenant la pièce métallique en affleurement du support thermoplastique 12 ou éventuellement en faible retrait, si l'on prend soin d'utiliser une pastille 36 de dimension inférieure à celle de l'encoche 26, pour maintenir le contact électrique avec la pièce métallique 14. La durée de chauffage et la pression appliquée par les électrodes 28,30 sont déterminées en fonction de la nature des matériaux à assembler. L'opération de soudage ne modifie pas le positionnement relatif du support 12 et de la pièce métallique 14, ce positionnement étant réalisé par tout moyen approprié notamment par des cales ou des empreintes ménagées sur les électrodes 28,30. Le faible jeu prévu entre la pièce métallique 14 et l'encoche 26 compense les imprécisions de fabrication, une compensation additionnelle pouvant résulter de la plasticité du support 12. La forme de l'encoche 26 est bien entendu conjuguée à celle de l'extrémité 16 de la pièce métallique 14 pour réaliser une fixation sur l'ensemble des faces de l'extrémité 16 logée dans l'encoche 26.In the figures, an electrical contact 10, in particular the movable contact of an electrical circuit breaker, consists of a support 12 made of a molded thermoplastic material and a metal part 14. The metal part 14 of flattened and elongated shape is assembled by the one 16 of its ends to the thermoplastic support 12 while the opposite end 18 carries a contact pad 20 capable of cooperating with a fixed contact in the closed position of the breaking device. The electrical contact 10 is pivotally mounted on an axis 22 passing perpendicularly through the thermoplastic support 12 of flattened and elongated shape. To the metal part 14 is welded a braid 24 for electrical connection. The metal part 14 extends in the extension of the thermoplastic support 12 and its end 16 is inserted into a notch 26 formed in the support 12. Such an electrical contact is well known per se, and it is unnecessary to describe it in more detail. The metal part 14 is fixed to the thermoplastic support 12 according to the invention by heating the metal part 14 so as to cause an overcooling of the thermoplastic material and an inlay of the metal part 14 in the notch 26. This operation is made on a welding machine, schematically shown in Figure 2, the thermoplastic support 12 with the metal part 14 inserted in the notch 26 being placed on a lower electrode 28 of the welding machine. The support 12 is placed flat on the face of the electrode 28, the notch 26 with the metal part 14 being oriented upwards in the direction of the upper electrode 30 of the welding machine. The lower electrode 28 carries a contact pad 32 projecting from the face of the electrode 28 to carry the end 18 of the metal piece 14. The height of the pad 32 compensates for the offset between the support 12 and the metal piece 14. The metal part 14 is held in mechanical and electrical contact with the pad 32 by a clamping system, schematically represented by an arm 34 of a jack which presses on the upper face of the metal piece 14 opposite the pad 32 The upper electrode 30 carries a contact pad 36 brought into contact with the end 16 of the metal part 14. The thickness of the metal part 14 is slightly greater than the depth of the notch 26 to produce a slight projection of the part 14, on which the pad 36 is applied for the welding operation. The welding operation is carried out by bringing the electrodes 28, 30 together, and by passing the current from the electrode 30 through the patch 36, the metal part 14 and the patch 32. The Joule effect heating of the metal part 14 causes a local melting of the thermoplastic material in contact with the metal part 14, and an inlay of the end 16 of the metal part 14 in the notch 26. This inlay can be accompanied by a slight penetration into the notch 26 bringing the metal part flush with the thermoplastic support 12 or possibly with slight shrinkage, if care is taken to use a patch 36 of dimension smaller than that of the notch 26, to maintain the electrical contact with the metal part 14. The heating time and the pressure applied by the electrodes 28.30 are determined depending on the nature of the materials to be assembled. The welding operation does not modify the relative positioning of the support 12 and of the metal part 14, this positioning being carried out by any appropriate means, in particular by wedges or imprints made on the electrodes 28, 30. The small clearance provided between the metal part 14 and the notch 26 compensates for manufacturing inaccuracies, additional compensation being able to result from the plasticity of the support 12. The shape of the notch 26 is of course combined with that of the end 16 of the metal part 14 for fixing on all of the faces of the end 16 housed in the notch 26.

La fixation de la tresse 24 sur la pièce métallique 14 peut être réalisée lors d'une opération suivante de soudage sur la même machine ou sur une autre machine, mais selon l'invention, cette opération de soudage est réalisée simultanément en insérant l'extrémité 38 de la tresse 24 entre la pastille 36 de l'électrode supérieure 30 et l'extrémité 16 de la pièce métallique 14. La pastille 36 de l'électrode supérieure 30 vient s'appliquer sur l'extrémité 38 de la tresse 24 et lors du passage du courant soude cette extrémité 38 sur la pièce métallique 14 de la manière usuelle. L'extrémité 38 peut bien entendu avoir été étamée au préalable. L'emploi d'une même machine et la réalisation simultanée du soudage de la tresse 24 et de la fixation de la pièce métallique 14 sur le support thermoplastique 12, permettent une économie appréciable de coût et de temps de fabrication.The braid 24 is fixed to the metal part 14 can be carried out during a following welding operation on the same machine or on another machine, but according to the invention, this welding operation is carried out simultaneously by inserting the end 38 of the braid 24 between the pad 36 of the upper electrode 30 and the end 16 of the metal part 14. The pad 36 of the upper electrode 30 is applied to the end 38 of the braid 24 and during the passage of the current welds this end 38 on the metal part 14 in the usual manner. The end 38 can of course have been tinned beforehand. The use of the same machine and the simultaneous production of the braid 24 and the fixing of the metal part 14 on the thermoplastic support 12, allow an appreciable saving in cost and manufacturing time.

Le contact électrique 10 est prêt à être monté dans l'appareil électrique et ne nécessite aucun traitement ultérieur notamment de nettoyage ou de rectification.The electrical contact 10 is ready to be mounted in the electrical appliance and does not require any further treatment, in particular cleaning or rectification.

L'invention est bien entendu nullement limitée à la fabrication d'un contact électrique et elle est utilisable à toute fixation d'une pièce métallique sur une pièce en un matériau thermoplastique.The invention is of course in no way limited to the manufacture an electrical contact and it can be used for any attachment of a metal part to a part made of a thermoplastic material.

Claims (8)

  1. A process for rigid fixing of a flattened metal part (14) onto a thermoplastic support (12), notably of a low voltage electrical contact onto a contact arm made of plastic material, wherein the thermoplastic support (12) has a recess (26) of a depth corresponding appreciably to the thickness of the flattened metal part, for flat insertion of the end of the metal part (14) without clearance, a process comprising the following stages; the thermoplastic support (12) is placed with the metal part (14) inserted in the recess (26) on a resistance welding machine one of the electrodes (28, 30) of which is in contact with the metal part, the metal part (14) is heated by applying an electrical current to incrust it in the thermoplastic support (12) causing local overmelting of the thermoplastic material and a pressure is exerted maintaining the metal part (14) in the recess (26) on the thermoplastic part during the heating operation to cause the melting thermoplastic material to rise and bring about incrustation.
  2. The fixing process according to claim 1, characterized in that the metal part (14) is flush with or slightly set back from the edges of the recess (26) after fixing onto the thermoplastic support (12) of elongated shape, extending the incrusted metal part.
  3. The fixing process according to claim 1 or 2, characterized in that said one (30) of the electrodes (28, 30) of the welding machine is held in contact with the free face of the metal part (14) at the level of the recess (26).
  4. The fixing process according to any one of the above claims, characterized in that the heating operation of the metal part (14) contributes to welding of an electrical conductor (24) to said metal part.
  5. The fixing process according to claim 4, characterized in that between the two electrodes (28, 30) of a resistance welding machine there are arranged the thermoplastic support (12) bearing the metal part (14) and the electrical conductor (24) placed flat on the free face of the metal part at the level of the recess (26) and that after the electrodes (28, 30) have been moved together to clamp the electrical conductor (24), metal part (14) and thermoplastic support (12), heating is performed by Joule effect by making a current flow from one electrode to the other through the metal part.
  6. The fixing process according to any one of the above claims, characterized in that the heating operation is performed on a capacitive discharge welding machine.
  7. The fixing process according to any one of the above claims, characterized in that means (32) for relative positioning hold the metal part (14) and thermoplastic support (12) in a predetermined position during the heating operation.
  8. The fixing process according to any one of the above claims, characterized in that the electrodes (28, 30) of the resistance welding machine, performing heating of the metal part, are made of material of low resistivity and high erosion withstand such as molybdenum or tungsten carbide pads (32, 36).
EP19880400782 1987-04-17 1988-03-30 Method for rigidly attaching a metal piece to a thermoplastic support, and a metal-thermoplastic electric contact Expired - Lifetime EP0287423B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8705657 1987-04-17
FR8705657A FR2614143B1 (en) 1987-04-17 1987-04-17 METHOD OF RIGID FIXING OF A METAL PART ON A THERMOPLASTIC SUPPORT AND ELECTRICAL CONTACT IN METAL AND THERMOPLASTIC

Publications (2)

Publication Number Publication Date
EP0287423A1 EP0287423A1 (en) 1988-10-19
EP0287423B1 true EP0287423B1 (en) 1993-12-29

Family

ID=9350352

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880400782 Expired - Lifetime EP0287423B1 (en) 1987-04-17 1988-03-30 Method for rigidly attaching a metal piece to a thermoplastic support, and a metal-thermoplastic electric contact

Country Status (4)

Country Link
EP (1) EP0287423B1 (en)
DE (1) DE3886580T2 (en)
ES (1) ES2049261T3 (en)
FR (1) FR2614143B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008039704A1 (en) * 2008-08-26 2010-03-04 Tyco Electronics Amp Gmbh Contact arrangement with bent strand, relay with contact arrangement and method for mounting a relay

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB943845A (en) * 1961-04-14 1963-12-11 Belling & Lee Ltd Improvements in or relating to securing a member in a mouldable electrical insulating material
US3497952A (en) * 1967-08-24 1970-03-03 Burndy Corp Method of assembling plastic and metal parts
US3781986A (en) * 1972-05-30 1974-01-01 Bendix Corp Method of mounting electrical contacts within a connector body

Also Published As

Publication number Publication date
FR2614143B1 (en) 1992-09-04
FR2614143A1 (en) 1988-10-21
DE3886580T2 (en) 1994-06-16
EP0287423A1 (en) 1988-10-19
ES2049261T3 (en) 1994-04-16
DE3886580D1 (en) 1994-02-10

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