BE678840A

BE678840A -

Info

Publication number: BE678840A
Authority: BE
Priority date: 1966-04-01
Filing date: 1966-04-01
Publication date: 1966-09-16

Description

  

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  Cintrage des tubes, 
La présente invention concerne des perfectionnements apportés aux machines utilisées pour mettre de petites lon-   gueurs   de tubes ou de tuyaux sous forme de coudes ou de cintres en vue de les incorporer, par soudure ou par tout autre moyen, dans un système de tuyauteries. 



   Dans la mise sous   forme   de coudes de petites longueurs de tubes sans soudure, il est désirable que la courbure du soude soit constante et que la section droite du tube demeure parfaitement circulaire. Il est désirable aussi de réduire autant que possible les variations d'épaisseur de la paroi du tube, c'est-à-dire l'amincissement qui se produit sur le rayon extérieur du coude et l'épaississement qui se produit sur le 

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   rayon     inférieur de   ce   coude.: Il   y a lieu d'éviter aussi les 
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 éraflrres et autres .J.úfcrma t :

   U1S de la surface extérieure et de la surface intérieure du tub', a.1nBi que tout autre dommage qui   pourrais   affaiblir le   coude ,}!    gêner   le passage du fluide qui y   circule. Une   norme A.S.T.M. spécifie les tolérances admis- 
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 1 sibles pour les accessoires de tuyauteries de ce type, et l'expérience a montré que la. présente invention permet de remplir à la fois des   conditions     générales   mentionnées plus haut et les prescriptions pour les tuyauteries coudées. 



   Considérée dans sa généralité, et suivant l'un de ses aspects, la présente invention consiste à former des coudes en 
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 l'oran. une longueur de tube de façon à la faire avancer longitudu bernent dans un passade forme entre deux parties d'un moule porteuses chacune d'une Suivant'l.'uii des modes de réalisation de l'invention, un mandrin libre est placé de façon à pénétrer dans l' extriJmi td art'ivre de la pièce mise en forme l'opération précédente et qui ains-. supporte et. maintient ce mandrin. La partie arrière de ce 'nandrin libre se loue à l'inté- rieur de l'extrémité avant de la pioce suivante et la supporte. 



  Selon un autre aspect de l'invention et une autre de ses modes 
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 de réalisation, la pièce h rnuttre en forme est forcée sur et contre   l'extrémité arrière     d'un   mandrin libre qui est maintenu 
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 et L,uid0 de façon à pouvoir se déplacer d'un mouvement circu- laire   outre   un   cylindre   et un moule tous deux munis d'une gorge, ce   déplacement   s'effectuant à   1' encontre   d'une force de résis- tance   susceptible   de   céder   sous la   pression   du   mandrin.   Dans les deux cas,

   la partie arrière du   mandrin     exerce   une poussée 

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 radialement et par sa partie intérieure vers la pièce de support   intérieur   et   s'appliqua   radialmeent et vers l'intérieur contre la paroi du tube pour y prendre appui. La partie arrière du mandrin presse progressivement   à   l'intérieur du tube contre la paroi extérieure de ce tube à partir de l'extrémité avant de   celui-ci   et vers sa partie médiane, le tube s'appliquant sur le support intérieur par sa surface intérieure. 



   Dans les deux cas, l'ébauche de laquelle le coude doit être tiré se déplace progressivement dans une gorge inté- rieure incurvée à partir d'une position initiale pour laquelle il est sensiblement tangent à cette gorge et en contact avec le moule, et poursuit son mouvement jusqu'à ce que le coude soit complètement formé. 



   L'appareil peut comprendre   un   plongeur associé avec un cylindre de support et qui agit, suivant un mode de réali- sation de l'invention, en coopération avec des éléments fixes de formage et un bloc fixe de   guidage   délimitant un passage de   section   droite et de rayon requis,   et,   dans un autre mode de réalisation de l'invention, agissant en coopération avec un dispositif maintenant le tube sur le   cylindre,   ce dispositif      cédant lentement sous la pression du tube etrefoulant le piston ;

   d'un cylindre hydraulique ou   pneumatique.   Le cylindre tournant de formate et les éléments fixât! de formate sont tous faits en acier 4 forte résistance d'un support   approprié.   Dans les deux cas, deux mandrins libres sont utilisés et agissent de façon à donner à la paroi du tube une courbure correspondant à celle du passage de formage. Dans les deux cas aussi   l'un   de ces mandrins est fixé sur l'extrémité d'un plongeur qui applique une pression sur la tranche arrière du tube. Selon un mode de 

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 réalisation, l'autre mandrin est libre de toute attache et se déplace avec la pièce en formage dans le passage de formage, tandis que dans la deuxième forme de réalisation, cet autre mandrin est relié à un cylindre hydraulique exerçant une force de résistance.

   Le mandrin libre porte un collet extérieur sur sa partie médiane, les tranches d'extrémité des tubes en cours de formage venant s'appuyer de part et d'autre sur ce collet. 



   Les deux mandrins sont faits en arier à haute   résis-   tance et les   dimensions   de leur surface extérieure correspondent aux dimensions intérieures de la paroi extérieure du coude que l'on veut obtenir, et sont   incuivées   dans les trois dimensions à partir de leur région médiane et vers leurs extrémités de façon à présenter sur l'extérieur des surfaces incurvées composites roulant progressivement sur le rayon extérieur du coude. Dans le premier mode de réalisation, le mandrin libre est de forme allongée et présente deux surfaces incurvées composites l'une sur son extrémité avant, l'autre sur son extrémité arrière, ce qui lui donne la forme générale d'un onglet  La pointe de l'extrémité avant de ce mandrin est chanfreinée pour faciliter son entrée dans la pièce précédemment formée.

   Les surfaces extérieures des deux mandrins sont incurvées à la fois   longi..     tudinalement   et transversalement et leur surface   Intérieure   est rectiligne dans le sens longitudinal mais incurvée transversale- ment en forme de cylindre, de sorte que ces mandrins se   Culminent     presque   en pointe sur leurs extrémités et présentent   clos   surfaces courbes composites sur leurs côtés,   La,   description qui va suivre, et les dessins annexés donnés surtout à titre d'exemple non limitatif, feront mieux comprendre comment la présente invention peut être réalisée,

   

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Sur les dessins   annexée   = la figure   1   est une coupe verticale faite dans une forme de réalisation d'une machine conforme à l'invention et destinée au formage à froid de tubes, le plongeur d'une presse étant représenté dans sa position de poussée sur une ébauche qui va être mise en forme et un mandrin libre étant   plao   entra cette ébautoche   et   la   plage   prédédente;

   - la   figure   2 est une vue on perspective d'un Manchon pouvant être monté sur le plongeur de   la.   presse et   transmettant   la force de poussée sur la pièce en cours de formage} -la figure '3 est la reproduction à plue grande échelle d'une partie de la figure l et qui montre l'infraction entre une   pièce,   en cours de formage et les   sur faces   de formage qui   agissent   sur cette pièce à la fin   d'une   course du plongeur;

   - la figure 4 montre la position dans la machine et la forme de deux pièces en cours de formage à un instant inter- médiaire entre l'introduction d'une ébauche à mettre en forme et l'évacuation d'un coude   formé;   - la figure 5 est la vue en élévation d'une ébauche de tube montrant la forme initiale-des extrémités de cette ébauche: - la figure 6 est une élévation représentant,un tube coudé obtenu en partant de l'ébauche de la figure 5; - la figure 7 est une élévation représentant le coude de la figure 6 dont les extrémités ont été affranchies à la longueur voulue et chanfreinée de façon à former un coude prêt à être soudé entre deux longueurs de tuyauterie; - la figure 8 est une élévation latérale représentant l'une des moitiés d'un moule fixe pouvant remplacer les organes formant moule de la, machine des figures 1 à 4;

        

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 - la figure 9 est une vue en élévation du moule complet dont l'une des parties est présentée sur la figure 8; - la figure 10 représente .e cylindre de formage et montre sa gorge formant moule et ses deux extrémités allongées formant   portée:

     - la figure 11 est une vue patieelemt en coupe et !   partiellement   on   élévation   d'une deuxième forma de   réalisation   de la   présents     Invention   et représentant un mandrin dont l'une des   extrémités   oppose une   résistance   cédant   progressivement   sous la poussée de la pièce à mettre en   formai   - la   figura   12   est   une vue partielle sembalge à la   figure   11 mais corrcspondant à une   position   des   pièces   de la   Machine   et du tube à cintrer lorsque Celui-di est déjà   partiel*   lemetn cintré;

   et - a figufe   13   est une vue partielle semblable 4 la figre 11 mais représentant les pièces de la machine et une   Pièce   à cintrer dans la position qu'elles ont lorsque la dite pièce a été complètement mise en forme, 
Ainsi qu'on le voit sur la figure l, un socle horizontal 15, métallique et robuste, supporte un châssis vertical 16,   métallique,   robuste, fixé sur le socle, dont la forme en plan est celle d'un U et qui est percé transversale- ment,   Un   cylindre de formage 17 est placé de façon que ses extrémités soient supportées dans le châssis 16 par un certain nombre de roulements à rouleaux 18, un seul de ces roulements étant représenté sur la figure.

   La partie du cylindre 17 qui se trouve entre les deux joues du châssis perte une gorge formant moule dont la section et le rayon intérieur correspondent à 

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      ceux de la surface incurvée intérieure du coude à. obtenir. Pour un tube à cintrer de diamètre donner le rayon de la gorge portée par le cylindre   17   doit   correspondre   au rayon désiré pour la surface intérieure du coude fini.

   Un support formant moule 22, porteur d'une gorge et en forme générale d'L est fixé en position dans le châssis   16   entre une plaque verticale dl appui 23 et une plaque de base   24.   De la sorte, la position du support   22   peut facilement être   réglée de   façon qu'une partie des bords de la gorge de ce support 22 coïncide avec les bords de la gorge du cylindre. 



  Un guide vertical 25 porte une   gorge de   formage comlémentaine de la gorge du supportfixe 22 et les bords de -'Jette gorge coïncident avec les borda   -le   celle de ce support   22   de façon à former un passais du diamètre désiré. L'extrémité inférieure du guide 25 épouse la forme de la surface latérale du cylindre 17 et sur cette extrémité sa gorge et celle du support 22 constituent   l'entrée   du pasrate ce formate dans lequel les   pièces   à cintrer seront   poussées,   e guide 25 est maintenu en position par une vis 29 ce vissant dans une traverse 30, engagée de façon amovible des échancrures ménagées dans les jours du châssis 16, et traversant   l'espace   intérieur de celui-ci. 



   Une plaque horizontale de formage 31   prolonge   la partie inférieure du support 22 et est Maintenue appliquée contre ce   support 'par   une vis de serrage 32 se vissant dans une traverse 33 qui, elle aussi, s'engage dans des échanorures du châssis   16   et traverse l'espace intérieur de ce châssis,   !-Et   plaque de formage 31 forme un   prolongement   de la gore du 

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 support 22, Cette gorge du support 22, lui se continue dans la plaque de formage   31,   a un   diamètre  sal à celui du diamètre j extérieur du coude que l'un désire obte'ir. 



   Comme on le voit sur la   figur''   5, les ébauches des- 
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 tinées à fournir les tubes cintrés ou ce ides sont des morceaux de tube 34 de faible longueur dont la petite 35 formera le rayon extérieur du coude fini et dont la partie 36 formera le rayon intérieur de ce coude. Du métal su   alimentaire   est prévu 
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 dans la région où la paroi du tube tendit, a s'allonge!!.- au cintrage. L'extrémité avant de l'ébauche qui pénètre la première dans le passage de fnrmage est ne forme irrégulière, et couple d'abord perpendiculairement à l'axe longitudinal      
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 de l'ébauche, ce qui dom.. .a ,, t,e 37 de cette extrémité., ;      puis coupé, obliquement par rapport à cet axe, ce qui donne la , partie 38 de cette extrémité.

   L'extrémité arrière de l'ébauche 
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 est aussi de forme irrê;"Ul1l::t'c et pcy:.e d'abord perpendiculaire- ment à l'axe longitudinal, eu cl': donne la partie 39 de cette extrémité, puis coupée obliquement par rapport à cet axe, ce qui donne la partie   40   de la dite   extrémité.   L'inclinaison de cette partie 40 sur l'axe est plus petite que celle de la partie 38.

   Après mise en forme, et comme le montre la figure 7, les coudes obtenus sont coupés à la longueur voulue et leurs 
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 extrémités ;}()ut chant'rein6Gs en kil pour permettre de les souder sur les extrémités de tuyauteries chanfreinées de la même   façon,   
Pour assurer la   régularité   de la mise en forme, il est prévu un mandrin 46, de forme allongée, robuste et rigide et sans 
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 aucune attache avec, aucune piil(e de la machine. Ce mandrin 46 porte un   collet     annulaire     47   sur sa partie médiane.

   Comme on le 
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 voit sur les figures 1< 3 et 4, la surface z±3 tournée vers 

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 l'intérieur du mandiim 46- des génératles longitudinales      rotilignes finis est   incurvée     transversalement,     tandis   que la surface de ce mandrin tournée vers   l'extérieur   est incurvée à la fois longitudinalement et transversalement de façon à former une surface extérieure de sortie 49 et une surface extérieure d'entrée 50 continues et de courbure comste.

   Ce mandrin a donc la forme générale d'une banane à extrémités pointues, 
La partie Intérieure de l'extrémité d'entrée du mandrin est chanfreinée en 51 pour faciliter sa pénétration à l'intérieur de la pièce précédent, 
Ainsi qu'on le voit sur les figures l à 4, le mandrin libre 46 coopère à la mise en forme de deux pièces successives. 



  Au cours de ce   formate,   l'extrémité avant uu mandrin pénètre et se trouve complètement entourée par   l'extrémité   arrière de la pièce précédente, et son extrémité arrière pénètre dans l'ex-   trémité   avant de la pièce à former suivante, en prenant appui en   porte-à-faux   sur sa paroi. 



   La surface intérieure 48 du mandrin est conforme au trou central du tube à cintrer et sec surfaces extérieures 49 et 
50 viennent en contact graduellement avec la paroi extérieure de la pièce en cours   de   cintrage au fur et à mesure que le mandrin   tourne   autour du cylindre. 



   Les ébaches à cintrer se trouver t poussées en suc- cession dans un passage   incurvé,   le passade représenté étant circulaire, par un ensemble comprenant un plongeur 75 dont l'extrémité avant de poussée 56 esten forme de segment comme l'extrémité avant du mandrin 46.

   L'extrémité du plongeur 56 est   rigidement   sur un manchon   52   qui est représenté à plus grande échelle sur les figures 2 et 3 La partie extérieure 

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      de   l'extraite   avant de ce Manchea une coupe irrégulière for- metn un éaulm,en   58   et,   transve.     salement,   deux angles vifs sépares par deux parties 59 en   for.;   de dents, la partie inté-   rieure   de cette extrémité du   manchon   étant   tailler     légèrement     en   biseau rentrant en 70. 



   Avant de commencer la première opération de mise en   truie,   une pièce rebutée est insérés dans le passage de formage et on fait   descendre   le plongeur 55.Cette pièce rebutée descend et s'introduit partiellement dans le passage. Le plongeur 55 est ensuite   releva et   un Mandrin libre 46 est placé dans le passage de   formée   de façon que son extrémité avant vienne se loger dans l'extrémité arrière de la pièce rebutée, son collet 47 portant sur la tranche de cette extrémité arrière. 



   La pièce rebutée prend alors la position que toutes les pièces prendront ap ¼sformage, la référence 34a désignant sur la figure 1 aussi hier. la pièce rebutée qu'une des pièces sui- vantes occupant la même position. 



   Une ébauche 34b est alors introduite de façon que son extrémité avant vienne coiffer l'extrémité arrière du mandrin 46, et le plongeur 55 de la presse est   descendu   à nouveau, vient porter sur l'extrémité arrière de l'ébauche 34b et l'entîne dans son mouvement. 



   Le plongeur   55   continuant son mouvement de descente, l'épaulment 58 qu'il porte vient en contact avec la partie plate 39 de   l'extrémité   arrière de l'ébauche 34b. Au moment où cette ébauche 34b   commence   à tourner autour du cylindre central, le   métal   flue pour laisser pénétrer les dents 59 de   l'extrémité   du manchon dans   l'extrémité   de la pièce ces dents venant progressivement   s'assoir   sur une parie de la surface   40   

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 de la pièce en cours de cintrage.

   La partie intérieure de cette surface 40 est libre de s'étendre longitudinalement et en direc- tion du manchon   57.   (Voir figure 3), Le mandrin 56 et la pièce 34b se déplacent constamment ensemble sans aucun mouvement relatif   appréciable.   Lorsque la pièce atteint l'entrée du passage en forme, l'extrémité arrière du mandrin 46 bascule et la surface extérieure 49 de son extrémité arrière vient progressivement   n   contact avec la paroi extérieure de la pièce 34b, la maintient à la forme voulue et la presse   à   l'intérieur de la gorge en forme. 



  (Comparer les figures 1 et 3). Cette action empêche les fibres de la moitié avant de la pièce 34b de s'aplatir en se retirant vers' l'arrière de l'extrémité avant de la   pièce* vers   sa'partie médiane. 



  Simultanément, la surface intérieure 48   du.   mandrin 46 supporte les fibres de la paroi intérieure et les empêche de s'affaisser sur l'extrémité avant de la pièce 34b en restant constamment en contact linéaire avec celle-ci au cours de la formation du cintre. 



   Le mandrin libre et la paroi extérieure de la pièce 34b demeurent fixes l'un par rapport à l'autre au cours du cintrage, aucun mouvement relatif axial entre les deux ne se produisant. 



  Mandrin et pièce ne se déplacent que   circulairement.   



   La paroi extérieure de la pièce 34b tend à s'étier au ' cours du cintrage. Voir figure 4. Mais, le collet 47 du mandrin exerce une réaction de compression longitudinale sur cette paroi extérieure de l'extrémité avant de la pièce, laquelle s'exerce sur la partie plane   37   et s'ajoute aux forces de réaction de   compression   longitudinales   enerdrées   par les frottements entre la surface extérieure de la pièce et le support formant moule 22. 



  Ainsi qu'on le voit au mieux sur la figure 4, la paroi intérieure de la deuxième pièce 34b n'est pas contrainte longiudinalement 

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 et peut se racourcir légèrement. Le fluage plasique maximum se fait suivant l'axe neutre c'est-à-dire   à   égal! distance entre la surface intérieure et la surface extérieur de la pièce, et les extrémités se trouvant ainsi mises sensibl 'ment à   l'équerre.   Les deux extrémités de la pièce sontaorurs en   général   à peu près planes comme on le voit sur la figure 5. 



   Au cours du cintrage, l'extrémité   ava't   du mandrin 46 s'insère rigidement dans l'extrémité arrière de la paroi inté rieure de la pièce 34b précédentece qui a pour effet de faire agir le mandrin dans son ensemble comme un levier travaillant en porte-à-faux et appliquant   -lui   forces dirigées vers l'exté- rieur 'par son extrémité arrière. De plus, l'extrémité avant du mandrin supporte l'extrémité arri   re   de la paroi extérieure de la pièce 34a après que s'est produit le mouvement de basculement mentionné plus haut. 



   Lorsque le plongeur 55 atteint l'extrémité de sa course descendante, comme sur la figure 3, la pièce précédente 34a (qui est une pièce rebutée pour l'opération préliminaire de mis en route, mais qui est une pièce finie pour les opérations subséquentes), est enlevée de   l'appareil.   Le plongeur est remonté à nouveau, un autre mandrin 46 est placé dans l'extré- mité arrière de la pièce demeurée dans l'appareil, une nouvelle ébauche est placée sur ce mandrin, et les opérations décrites sont reprises autant de fois que nécessaire. 



   Les tubes d'acier inoxydable ont tendance à gripper lorsqu'ils sont soumis   à   un cintrage à froid et qu'ils frottent en s'appuyant fortement sur une autre surface. Au lieu d'utiliser un cylindre intérieur de formage et un moule extérieur fixe portant une rainure, on peut utiliser un mole fait en deux 

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 parties   fixes,' comme   représenté sur les figures 8 et 9, ces   orties   fixes étant faites en un alliage approprié. La figure 8   représente   une moitié d'un moule de formage fixe, fait en un alliage présentant une grande résistance et une faible tendance au grippage, le bronze d'aluminium ayant été trouvé satisfaisant à ces points de vue.

   Le moule complet se compose d'une moitié de droite 64 et d'une moitié de gauche 65 fixées en position relative exacte au moyen de goujons 66 et maintenues serrées l'une contre l'autre par des boulons 67. L'ensemble ainsi constitué peut être placé sur le plateau d'une presse appropriée. 



  L'utilisation et   l'action   du mandrin libre 46, et la succession des opérations sont les   marnes   que celles décrites pour les figurée l à 4. 



   Sur   les   figures   11     à   13 on voit que l'appareil repré- sente comporte aussi un organe de formage en forme de cylindre mais que le mandrin libre y est remplacé par un mandrin avant fixé rigidement au cylindre. L'introduction des pièces dans l'appareil est plus simple, la précision de la mise en position de l'ébauche est augmentée et l'action du mandrin avant sur la pièce en cintrage est   améliorée.   L'appareil de formage comporte dans ce cas aussi un socle horizontal 70 relativement lourds et un châssis formé par deux plaques verticales 71, distantes l'une de   l'autre,   s'élevant au-dessus du socle et fixées sur celui-ci.

   Un cylindre 72 porteur d'une gorge est monté de façon à traverser l'espace existant entre les deux plaques verticales et tourne sur des roulements à rouleaux appropriés 73 Le cylindre 72 est rigidement fixé sur un ensemble portant le mandrin avant et constitué par un bloc 74 qui   est 4   son tour fixé sur un levier 75   connecté-sur   l'extrémité du piston 76 d'un vérin 

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 hydraulique 77, oe vérin pivotant en 78 sur un support d'appui 
79.

   Ce vérin hydraulique et son piston sont tels qu'ils créent une résistance modérée s'opposant au mouvement du cylindre formeur et leur position peut être réglée pour régler oelle de ce cylindre   tormeur.   Le bloc 74 porte un alésage et un embrèvement dans lequel est solidement maintenue l'extrémité avant d'un mandrin 83 au moyen d'un boulon 84. La forme et le rôle du mandrin 83 sont les mêmes que ceux de la moitié arrière du mandrin 46. Le mandrin 
83 porte sur son extrémité avant un collet 85 sur lequel vient   s'assoir   un manchon 86. L'extrémité avant de ce manchon 86 est plane et perpendiculaire à l'axe alors que son extrémité arrière est fobijqeu suivant un angle qui correspond à celui de l'icli-   saison   de l'extrémité avant d'une ébaucha 34 placée sur le mandrin 
83.

   Une partie   incurvée   de faible profondeur est prévue dans l'embrèvment bloc 74 pour recevoir   l'extrémité   d'une pièce 34 et offrir un support radial aux fibres extérieures de l'extrémité avant de la pièce au coure du cintrage, Un moule ou guide 89 porteur d'une gorge glisse sur le   coda   70 et supporte un ensemble comportant un plongeur de près* sion 90 muni d'un mandrin plongeur 91 en forme d'onglet fixé sur le plongeur et un manchon 92 dont les extrémités ont une forme semblable à celle du manchon des figures'1 à 4. Le plongeur 90 est rigidement fixé sur le guide 89 par une bride 93.

   Les mandrins 83 et   91   sont solidaires de leurs supports respectifs, et   l'extré-   mité avant du mandrin 91 est raccourcie pour laisser passer l'extrémité du mandrin 83 comme on le voit sur la figure 11. 



   Le fonctionnement de l'appareil est le suivant ; le bloc 74 et le mandrin 83 qu'il porte étant dans la position   re-   présentée sur la figure   11,   et le plongeur 90 et le mandrin 91 étant sur leur position de retrait, une ébauche 34 peut être mise 

 <Desc/Clms Page number 15> 

 en   pétition   dans l'appareil de   façon   qu'elle s'assoie sur le   mandrin   86 et repose dans lt gorge du guide 89. Le manchon 92 du plongeur de   pression   est alors déplacé axialement de façon à venir pousser la pièce et la faire mouvoir contre la réaction du vérin hydraulique 77.

   La force exercée par le plongeur de pression 90 doit être assez forte pour vaincre la résistance opposée par le vérin 77.Le bloc 74 et son mandrin 83 se déplacent alors suivant un trajet incurve autour du centre de la gorge du cylindre formeur et prennent successivement des   positions     repré-     sentées   sur les   figures   12 et 13, Sur la figure   12,   la pièce      en cours de cintrage est   cintrée   autour du cylindre   fèrmeur   72 par   l'extrémité   avant du mandrin   prisonnier   83 et par 'la   gorge   de 
 EMI15.1 
 faible profondeur qui 1 entoura.

   Comme dans le pramiair mode de ïaUoatton da l'invwobiono le Mandrin 8T)-ba.tfou da façon ue $A au'aa oxt4vieure vient. progrosoivemont en contgot Avec la paroi nzb4r$ouro do le, moitié avant da la pièce et ilemptolie eo 9ppltt6<.P<(ctnpaï'ay les figures Il et 18), 9imultannant, la oure4co inieMpe du Mandrin 83 vient supporter intérieurement .axrc3m.

   avant da la, piooo suivant un o<antaot< linéaire et llompgohe de elattainser durant toute la formation du coudent aida en même temps à appliquer fortement la paroi intérieure de la   pièce   dans la gorge du cylindre   formeur,   Le mandrin plongeur      91 supporte par   l'intérieur   l'extrémité arrière de la   pièce   et l'empêche de s'affaisser pendant toute la durée du cintrage en permettant aux fibres intérieures de la pièce d'ajuster leur position relative par glissement relatif, comme on le voit' sur la figure 13, D'autre part, il ne se produit aucun   mouve-   ment relatif axial ou longitudinal appréciable entre les mandrins et la pièce au cours du cintrage,

   La gorge du guide 89 

 <Desc/Clms Page number 16> 

 exerce des forces de flexion   dirigées   vers   l'intérieur   en coopé- ration avec le mandrin 91 sur l'extrémité arrière de la pièce Et détermine ainsi le diamètre extérieur   de \ celle-ci.   Lorsque la position est celle représentée sur la figure 3. le cintrage est terminé.

   La pression à l'intérieur duvérin   77   est alors inversée tandis que   [Le   mandrin plongeur 91 est retiré sur sa position   Initiale.   La pièce cintrée est alors retirée à la main, après quoi le vérin   77   est actionné de façon à faire revenir vers, l'avant le mandrin 83 et le cylindre formeur 62 sur leur position        initiale,   ce qui termine le cycle opératoire, 
Dans ce deuxième mode db   réalisation,   il n'existe pas de gorge extérieure   remplissent   le même rôle que la   gorge   du support formant moule 22 et que la plaque horizontale de fomreage 31 de la   figura   l, espté la gorge   prévue   dans le   guide   89,

   
La   présente     invention   constiure un perfectionmet notable   des     procédés     antérieurs   de   cintrage   des   bubon     lorsque   cette opération   doit;

     se faire à foroid, L'affaissement de    parois   est   impossible   durant   l'opération   de   formage,   contrairemetn à ce qui se passe dans l'application des   procédé    antérieurement   connu    ce qui nécessitant une remisa en   forma   de la pièe cintrée L' épaisseur   des     parois   de la pièce finie est   sensiblement   uniforme en toutes les parties de cette pièce, 
Bien entendu la présente invention n'est pas limitée aux modes de réalisation décrits mais s'étend à toutes les variantes conformes + son esprit,



   <Desc / Clms Page number 1>
 



  Tube bending,
The present invention relates to improvements made to machines used for placing short lengths of tubes or pipes in the form of elbows or bends with a view to incorporating them, by welding or by any other means, into a piping system.



   In bending short lengths of seamless tubing, it is desirable that the curvature of the soda be constant and that the cross section of the tubing remains perfectly circular. It is also desirable to reduce as much as possible the variations in thickness of the tube wall, i.e. the thinning which occurs on the outer radius of the bend and the thickening which occurs on the

 <Desc / Clms Page number 2>

   lower radius of this bend: It is also necessary to avoid
 EMI2.1
 scuffers and others .J.úfcrma t:

   U1S of the exterior and interior surfaces of the tub ', a.1nBi than any other damage which could weaken the elbow,}! obstruct the passage of the fluid which circulates therein. An A.S.T.M. specifies the tolerances allowed
 EMI2.2
 1 sibles for pipe fittings of this type, and experience has shown that the. The present invention makes it possible to meet both the general conditions mentioned above and the requirements for bent pipes.



   Considered in general, and according to one of its aspects, the present invention consists in forming elbows in
 EMI2.3
 the oran. a length of tube so as to advance it longitudu bernent in a passage form between two parts of a mold each carrying a According to the embodiments of the invention, a free mandrel is placed so to penetrate into the extriJmi td art'Drunk of the shaped part the previous operation and which thus. supports and. maintains this mandrel. The rear part of this free nandrin hires out inside the front end of the next room and supports it.



  According to another aspect of the invention and another of its modes
 EMI2.4
 embodiment, the shaped part is forced onto and against the rear end of a free mandrel which is held
 EMI2.5
 and L, uid0 so as to be able to move in a circular motion beyond a cylinder and a mold both provided with a groove, this displacement being effected against a resisting force capable of. yield under the pressure of the mandrel. In both cases,

   the rear part of the chuck pushes

 <Desc / Clms Page number 3>

 radially and by its inner part towards the inner support piece and applied radially and inwardly against the wall of the tube to rest thereon. The rear part of the mandrel gradually presses inside the tube against the outer wall of this tube from the front end of the latter and towards its middle part, the tube being applied to the inner support by its inner surface. .



   In both cases, the blank from which the elbow is to be pulled progressively moves in an internal curved groove from an initial position for which it is substantially tangent to this groove and in contact with the mold, and continues its movement until the elbow is fully formed.



   The apparatus may comprise a plunger associated with a support cylinder and which acts, according to an embodiment of the invention, in cooperation with fixed forming elements and a fixed guide block delimiting a passage of straight section and radius required, and, in another embodiment of the invention, acting in cooperation with a device holding the tube on the cylinder, this device slowly yielding under the pressure of the tube and pushing the piston;

   a hydraulic or pneumatic cylinder. The rotating format cylinder and the elements fixed! of formate are all made of 4 strong steel with a suitable support. In both cases, two free mandrels are used and act to give the tube wall a curvature corresponding to that of the forming passage. In both cases also one of these mandrels is attached to the end of a plunger which applies pressure to the rear edge of the tube. According to a mode of

 <Desc / Clms Page number 4>

 In the embodiment, the other mandrel is free of any fasteners and moves with the workpiece in the forming passage, while in the second embodiment, this other mandrel is connected to a hydraulic cylinder exerting a resistance force.

   The free mandrel carries an external collar on its middle part, the end edges of the tubes being formed coming to rest on either side on this collar.



   The two mandrels are made of high strength arier and the dimensions of their outer surface correspond to the inner dimensions of the outer wall of the elbow to be obtained, and are incuivated in the three dimensions from their middle region and towards their ends so as to present on the outside of the curved composite surfaces rolling progressively on the outer radius of the bend. In the first embodiment, the free mandrel is of elongated shape and has two composite curved surfaces one on its front end, the other on its rear end, which gives it the general shape of a tab. the front end of this mandrel is chamfered to facilitate its entry into the previously formed part.

   The outer surfaces of the two mandrels are curved both lengthwise and transversely and their inner surface is rectilinear in the longitudinal direction but transversely curved in the form of a cylinder, so that these mandrels culminate almost in a point at their ends. and have closed composite curved surfaces on their sides, The description which follows, and the accompanying drawings, given mainly by way of non-limiting example, will make it easier to understand how the present invention can be achieved,

   

 <Desc / Clms Page number 5>

 
In the accompanying drawings = Figure 1 is a vertical section taken in one embodiment of a machine according to the invention and intended for cold forming of tubes, the plunger of a press being shown in its pushed position on a blank which will be shaped and a free mandrel being placed between this blank and the previous range;

   - Figure 2 is a perspective view of a sleeve which can be mounted on the plunger of the. pressing and transmitting the pushing force on the part being formed} -Figure 3 is a larger scale reproduction of part of figure 1 and which shows the infringement between a part being formed and the forming surfaces which act on this part at the end of a plunger stroke;

   FIG. 4 shows the position in the machine and the shape of two parts being formed at an intermediate instant between the introduction of a blank to be shaped and the discharge of a formed bend; - Figure 5 is the elevational view of a tube blank showing the initial shape of the ends of this blank: - Figure 6 is an elevation showing a bent tube obtained starting from the blank of Figure 5; - Figure 7 is an elevation showing the bend of Figure 6, the ends of which have been franked to the desired length and chamfered so as to form an elbow ready to be welded between two lengths of pipe; FIG. 8 is a side elevation showing one of the halves of a stationary mold capable of replacing the mold members of the machine of FIGS. 1 to 4;

        

 <Desc / Clms Page number 6>

 - Figure 9 is an elevational view of the complete mold, one of the parts of which is shown in Figure 8; - Figure 10 represents .e forming cylinder and shows its groove forming a mold and its two elongated ends forming a bearing:

     - Figure 11 is a sectional patieelemt view and! partially elevation of a second form of embodiment of the present invention and showing a mandrel one of whose ends opposes a resistance gradually yielding under the thrust of the part to be shaped - figure 12 is a partial view shown at the bottom. FIG. 11 but corresponding to a position of the parts of the Machine and of the tube to be bent when the latter is already partial * lemetn bent;

   and - a figufe 13 is a partial view similar to figre 11 but showing the parts of the machine and a part to be bent in the position they have when said part has been completely shaped,
As seen in Figure l, a horizontal base 15, metal and robust, supports a vertical frame 16, metal, robust, fixed on the base, the plan shape of which is that of a U and which is drilled transversely, a forming cylinder 17 is placed so that its ends are supported in the frame 16 by a number of roller bearings 18, only one of these bearings being shown in the figure.

   The part of cylinder 17 which is located between the two cheeks of the frame loses a mold-forming groove whose section and internal radius correspond to

 <Desc / Clms Page number 7>

      those of the inner curved surface of the elbow to. get. For a diameter tube to be bent, give the radius of the groove carried by the cylinder 17 must correspond to the radius desired for the interior surface of the finished bend.

   A support forming a mold 22, carrying a groove and in the general shape of an L, is fixed in position in the frame 16 between a vertical support plate 23 and a base plate 24. In this way, the position of the support 22 can be adjusted. easily be adjusted so that part of the edges of the groove of this support 22 coincide with the edges of the groove of the cylinder.



  A vertical guide 25 carries a comlémentaine forming groove of the groove of the fixed support 22 and the edges of -'Jette groove coincide with the borda -le that of this support 22 so as to form a pass of the desired diameter. The lower end of the guide 25 conforms to the shape of the lateral surface of the cylinder 17 and on this end its groove and that of the support 22 constitute the entry of the pasrate this format in which the parts to be bent will be pushed, the guide 25 is maintained in position by a screw 29 this screwing into a cross member 30, removably engaged with the notches formed in the openings of the frame 16, and passing through the interior space thereof.



   A horizontal forming plate 31 extends the lower part of the support 22 and is held pressed against this support by a clamping screw 32 screwing into a cross member 33 which, in turn, engages in the notches of the frame 16 and passes through the interior space of this frame,! -And forming plate 31 forms an extension of the gore of the

 <Desc / Clms Page number 8>

 support 22, This groove in support 22, it continues in forming plate 31, has a diameter sal to that of the outside diameter of the elbow that one wishes to obtain.



   As can be seen in figure 5, the sketches of the
 EMI8.1
 Tines to provide the bent tubes or these ides are pieces of tube 34 of short length, the small 35 of which will form the outer radius of the finished bend and part 36 of which will form the inner radius of this bend. Food metal is provided
 EMI8.2
 in the region where the tube wall is stretched, a elongates !! .- when bending. The front end of the blank which first enters the finishing passage is irregular in shape, and first couples perpendicular to the longitudinal axis.
 EMI8.3
 of the blank, which dom .. .a ,, t, e 37 from this end.,; then cut obliquely with respect to this axis, which gives the part 38 of this end.

   The rear end of the blank
 EMI8.4
 is also of form irê; "Ul1l :: t'c and pcy: .e first perpendicular to the longitudinal axis, eu cl ': gives part 39 of this end, then cut obliquely with respect to this axis , which gives said end part 40. The inclination of this part 40 on the axis is smaller than that of part 38.

   After shaping, and as shown in Figure 7, the elbows obtained are cut to the desired length and their
 EMI8.5
 ends;} () ut chant'rein6Gs in kilograms to allow them to be welded on the ends of pipes chamfered in the same way,
To ensure the regularity of the shaping, a mandrel 46 is provided, of elongated shape, robust and rigid and without
 EMI8.6
 no attachment with, no piil (e of the machine. This mandrel 46 carries an annular collar 47 on its middle part.

   As we
 EMI8.7
 see in figures 1 <3 and 4, the surface z ± 3 turned towards

 <Desc / Clms Page number 9>

 the interior of the mandrel 46- of the finished rotilinear longitudinal generatles is curved transversely, while the surface of this mandrel facing outwards is curved both longitudinally and transversely so as to form an outer exit surface 49 and an outer surface input 50 continuous and curvature comste.

   This mandrel therefore has the general shape of a banana with pointed ends,
The inner part of the inlet end of the mandrel is chamfered at 51 to facilitate its penetration inside the previous part,
As seen in Figures l to 4, the free mandrel 46 cooperates in the shaping of two successive parts.



  During this formatting, the front end of the mandrel enters and is completely surrounded by the rear end of the previous part, and its rear end enters the front end of the next part to be formed, resting cantilevered on its wall.



   The inner surface 48 of the mandrel conforms to the central hole of the tube to be bent and dry outer surfaces 49 and
50 gradually come into contact with the outer wall of the part being bent as the mandrel rotates around the cylinder.



   The blanks to be bent are pushed in succession in a curved passage, the passage shown being circular, by an assembly comprising a plunger 75 whose front thrust end 56 is in the form of a segment like the front end of the mandrel 46 .

   The end of the plunger 56 is rigidly on a sleeve 52 which is shown on a larger scale in Figures 2 and 3 The outer part

 <Desc / Clms Page number 10>

      of the extract before this Manchea an irregular cut forms a shoulder, in 58 and, transve. dirty, two sharp angles separated by two parts 59 in for .; teeth, the inner part of this end of the sleeve being cut slightly at a bevel entering at 70.



   Before starting the first sowing operation, a rejected part is inserted into the forming passage and the plunger 55 is lowered. This rejected part descends and partially enters the passage. The plunger 55 is then raised and a free mandrel 46 is placed in the formed passage so that its front end comes to be housed in the rear end of the rejected part, its collar 47 bearing on the edge of this rear end.



   The rejected part then takes the position that all the parts will take after forming, the reference 34a designating in FIG. 1 also yesterday. the rejected part than one of the following parts occupying the same position.



   A blank 34b is then introduced so that its front end comes to cover the rear end of the mandrel 46, and the plunger 55 of the press is lowered again, bears on the rear end of the blank 34b and drives it In his movement.



   The plunger 55 continuing its downward movement, the shoulder 58 which it carries comes into contact with the flat part 39 of the rear end of the blank 34b. When this blank 34b begins to rotate around the central cylinder, the metal flows to allow the teeth 59 of the end of the sleeve to penetrate into the end of the part, these teeth gradually coming to sit on a part of the surface 40

 <Desc / Clms Page number 11>

 of the part being bent.

   The interior portion of this surface 40 is free to extend longitudinally and in the direction of the sleeve 57. (See Figure 3), the mandrel 56 and the workpiece 34b are constantly moving together without any appreciable relative movement. When the part reaches the entrance to the shaped passage, the rear end of the mandrel 46 tilts and the outer surface 49 of its rear end gradually comes into contact with the outer wall of the part 34b, maintains it in the desired shape and press inside the throat shaped.



  (Compare Figures 1 and 3). This action prevents the fibers of the front half of the patch 34b from flattening as they retreat rearward from the front end of the patch * towards its middle part.



  Simultaneously, the interior surface 48 of the. mandrel 46 supports the fibers of the inner wall and prevents them from sagging on the front end of the workpiece 34b by remaining in constant linear contact therewith during the formation of the hanger.



   The free mandrel and the outer wall of the part 34b remain fixed with respect to each other during the bending, no axial relative movement between the two occurring.



  Mandrel and workpiece only move circularly.



   The outer wall of the part 34b tends to squeeze during bending. See figure 4. But, the collet 47 of the mandrel exerts a longitudinal compression reaction on this outer wall of the front end of the part, which is exerted on the flat part 37 and adds to the longitudinal compression reaction forces. enerdées by the friction between the outer surface of the part and the support forming the mold 22.



  As best seen in Figure 4, the inner wall of the second part 34b is not constrained longiudinally

 <Desc / Clms Page number 12>

 and may shorten slightly. The maximum plastic creep is done along the neutral axis that is to say on an equal footing! distance between the interior surface and the exterior surface of the part, and the ends thus being placed sensibl 'ment squared. The two ends of the part are generally roughly flat as seen in Figure 5.



   During the bending, the front end of the mandrel 46 fits rigidly into the rear end of the inner wall of the previous part 34b which has the effect of making the mandrel as a whole act as a lever working in cantilever and applying it outwardly directed forces from its rear end. In addition, the front end of the mandrel supports the rear end of the outer wall of the part 34a after the aforementioned rocking movement has occurred.



   When the plunger 55 reaches the end of its downward stroke, as in Figure 3, the previous part 34a (which is a part rejected for the preliminary operation of start-up, but which is a finished part for the subsequent operations) , is removed from the device. The plunger is reassembled again, another mandrel 46 is placed in the rear end of the part remaining in the apparatus, a new blank is placed on this mandrel, and the operations described are repeated as many times as necessary.



   Stainless steel tubing has a tendency to seize when subjected to cold bending and rubbing with heavy pressure on another surface. Instead of using an inner forming cylinder and a fixed outer mold with a groove, a mole made in two can be used.

 <Desc / Clms Page number 13>

 fixed parts, 'as shown in Figures 8 and 9, these fixed nettles being made of a suitable alloy. Fig. 8 shows one half of a stationary forming mold, made of an alloy exhibiting high strength and low tendency to seize, aluminum bronze having been found to be satisfactory from these points of view.

   The complete mold consists of a right half 64 and a left half 65 fixed in exact relative position by means of studs 66 and held tight against each other by bolts 67. The assembly thus formed can be placed on the bed of a suitable press.



  The use and the action of the free mandrel 46, and the succession of operations are the marls as those described for the figures l to 4.



   In FIGS. 11 to 13 it can be seen that the apparatus represented also comprises a forming member in the form of a cylinder, but that the free mandrel is replaced there by a front mandrel rigidly fixed to the cylinder. The introduction of the parts into the apparatus is simpler, the precision of the positioning of the blank is increased and the action of the front mandrel on the bending part is improved. The forming apparatus also comprises in this case also a relatively heavy horizontal base 70 and a frame formed by two vertical plates 71, spaced apart from one another, rising above the base and fixed thereon.

   A cylinder 72 carrying a groove is mounted so as to pass through the space existing between the two vertical plates and rotates on suitable roller bearings 73 The cylinder 72 is rigidly fixed on an assembly carrying the front mandrel and consisting of a block 74 which is 4 in turn fixed to a lever 75 connected to the end of the piston 76 of a cylinder

 <Desc / Clms Page number 14>

 hydraulic 77, oe pivoting cylinder in 78 on a support support
79.

   This hydraulic cylinder and its piston are such that they create a moderate resistance opposing the movement of the forming cylinder and their position can be adjusted to adjust the position of this forming cylinder. Block 74 has a bore and recess in which the front end of a mandrel 83 is securely held by means of a bolt 84. The shape and function of mandrel 83 are the same as those of the rear half of the mandrel. 46. The chuck
83 carries on its front end a collar 85 on which a sleeve 86 sits. The front end of this sleeve 86 is plane and perpendicular to the axis while its rear end is fobijqeu at an angle which corresponds to that of the icli- season of the front end of a blank 34 placed on the mandrel
83.

   A shallow curved portion is provided in the block recess 74 to receive the end of a part 34 and provide radial support to the outer fibers of the front end of the part during the bending. A mold or guide 89 a groove carrier slides on the coda 70 and supports an assembly comprising a close-up plunger 90 provided with a plunger mandrel 91 in the form of a tab fixed on the plunger and a sleeve 92 whose ends have a shape similar to that of the sleeve of Figures'1 to 4. The plunger 90 is rigidly fixed to the guide 89 by a flange 93.

   The mandrels 83 and 91 are integral with their respective supports, and the front end of the mandrel 91 is shortened to allow the end of the mandrel 83 to pass as seen in FIG. 11.



   The operation of the apparatus is as follows; the block 74 and the mandrel 83 which it carries being in the position shown in FIG. 11, and the plunger 90 and the mandrel 91 being in their withdrawn position, a blank 34 can be placed

 <Desc / Clms Page number 15>

 in petition in the apparatus so that it sits on the mandrel 86 and rests in the groove of the guide 89. The sleeve 92 of the pressure plunger is then moved axially so as to push the part and make it move against the reaction of the hydraulic cylinder 77.

   The force exerted by the pressure plunger 90 must be strong enough to overcome the resistance opposed by the cylinder 77. The block 74 and its mandrel 83 then move in a curved path around the center of the groove of the forming cylinder and take successive steps. positions shown in Figures 12 and 13, In Figure 12, the part being bent is bent around the locking cylinder 72 by the front end of the captive mandrel 83 and by the groove of
 EMI15.1
 shallow depth surrounding it.

   As in the pramiair mode of ïaUoatton da invwobiono the Chuck 8T) -ba. progrosoivemont en contgot With the wall nzb4r $ ouro do le, front half of the room and ilemptolie eo 9ppltt6 <.P <(ctnpaï'ay figures II and 18), 9 simultaneously, the oure4co inieMpe of Mandrel 83 comes to support internally .axrc3m.

   before it, piooo following a linear o <antaot <and llompgohe de elattainser during all the formation of the elbow at the same time helped to strongly apply the inner wall of the part in the groove of the forming cylinder, The plunger mandrel 91 supported by the inside the rear end of the part and prevents it from sagging throughout the bending period by allowing the inner fibers of the part to adjust their relative position by relative sliding, as seen in Figure 13, On the other hand, no appreciable axial or longitudinal relative movement occurs between the mandrels and the workpiece during bending,

   The guide's throat 89

 <Desc / Clms Page number 16>

 exerts inwardly directed bending forces in cooperation with the mandrel 91 on the rear end of the workpiece and thereby determines the outer diameter thereof. When the position is that shown in Figure 3. the bending is complete.

   The pressure inside the actuator 77 is then reversed while [The plunger mandrel 91 is withdrawn to its Initial position. The bent part is then removed by hand, after which the jack 77 is actuated so as to return the mandrel 83 and the forming cylinder 62 towards the front to their initial position, which ends the operating cycle,
In this second embodiment, there is no external groove fulfilling the same role as the groove of the mold support 22 and as the horizontal shaping plate 31 of the figure l, expected the groove provided in the guide 89,

   
The present invention constitutes a notable perfection of the prior methods of bending buboes when this operation must;

     to be done foroid, The collapse of the walls is impossible during the forming operation, contrary to what happens in the application of previously known process which requires a storage in forma of the curved piece The thickness of the walls of the finished part is substantially uniform in all parts of this part,
Of course, the present invention is not limited to the embodiments described but extends to all the variants in accordance with its spirit,

Claims

. Summary, 1, A machine for the cold bending of lengths of tubes comprising, in combination a) a frame, b) a cylinder carrying a peripheral groove of partially circular cross section, which can turn in the frame, c) a member placed on the frame and forming with the cylinder a forming passage for the placing of a tube in the form of an elbow (of given inside radius and outside radius, d) a first device receiving the front end of a tube, placed in the forming passage and capable of moving with the tube in the forming passage in fixed longitudinal relation to the tube, this first device being arranged so as to progressively support the outer wall of the tube and prevent it from falling. flatten on its front half during its movement, e)

a second device penetrating into the rear end of the tube and arranged so as to move in fixed axial relation with this tube over a part of the forming passage, f) this first device and this second device acting in cooperation for the setting in the form of a tube at the radius of the passage, 2, A following machine 1, in which the second device comprises a thrust plunger on which is fixed a sleeve which pushes on the rear end of the tube in a fixed position with respect to the end of the plunger, and in which the 'sleeve bears only on a part of the rear end of the tube by means of a shoulder and teeth placed between <Desc / Clms Page number 18> the outer radius and the inner radius of the tube,

and said - sleeve stopping at a certain distance from the end of the tube on the radius of the inner wall of the tube, 3. A following machine 1, in which the first device comprises a front mandrel provided with an external collar on its median part, on which collar are supported simultaneously two ends of tube belonging to two lengths of tubes respectively. successive, 4, A following machine 1, in which the first device comprises a front mandrel provided with an outer collar on its median part, which collar is supported simultaneously by two ends belonging respectively to two successive lengths of tubes,

and whose diameter is substantially equal to the forming diameter so that this collar can act in conjunction with the leading end of the length of tube to resist the axial movement of the next length of tube as it moves in part of the forming passage, ' 5, A following machine 1, in which the first device comprises a front mandrel provided with an outer collar on its middle part, this mandrel tapering off from the collar and towards its two ends to come to support both the wall of the tube on its inner radius and on its outer radius in the front half of the tube, and the second device comprises a pressure plunger, one end of which has the same shape as the adjacent end of the conductive mandrel.

6. An apparatus for forming elbows starting from rectigian tabular blanks, comprising; <Desc / Clms Page number 19> a) a forming member carrying a groove, the bottom of which has a radius equal to the inner radius of the bend to be formed, b) a device which causes the blank to move progressively along the said incurie groove from an initial position for which it is substantially tangent to the groove and in contact with the forming member, the movement continuing until the bend is formed, c) and separate devices for shaping the blank,

placed inside each of the ends of this blank and having an outside radius and a configuration corresponding to the longitudinal and transverse inside radii of the finished bend in its part of maximum outside radius, the device for shaping the blank placed on the front end of the blank being arranged to act as a cantilever lever to gradually support the outer wall of the tube and prevent it from flattening in its front half during movement of the blank, d) the shaping device moving with the blank during the elbow forming operation.

7. A machine according to 6, comprising a device Opposing the movement of the blank in its path in the said groove but yielding under the pressure of the blank.

8. A following machine 6, in which the forming member is constituted by a movable forming cylinder, a hydraulic cylinder being rigidly connected with this cylinder and resistant, while yielding, to the movement of the cylinder.

9. A following machine 6, in which the member for shaping the preform comprises a front mandrel and a plunger. <Desc / Clms Page number 20> rear pressure, this mandrel and this plunger each being integral with a sleeve respectively bearing on the associated end of the blank in a fixed relative axial position with respect to this blank during its movement around the forming member, 10. A continuous machine for placing rectilinear tubular blanks in the form of elbows, comprising;

a) a forming device forming a curved passage receiving in succession a series of blanks which traverse it, b) and a device causing this to move -.;! blanks progressively and in succession over the entire length of said passage, this device comprising a free mandrel placed inside the forming passage, c) the avart end of said mandrel having a shape allowing it to penetrate into the forming passage. rear end of the previous blank to support it and prevent it from sagging, d) the rear part of this mandrel having a shape allowing it to penetrate into the front part of the next blank to support it and prevent it to sag, e)

this mandrel moving in the forming passage at the same time as the previous blank and the following blank during the formation of the elbow, 11. A following machine 10, in which the mandrel consists of: a) an elongated member in the general shape of a segment of a circle, b) the inner surface of this mandrel being rectilinear in the longitudinal direction but curved in the direction. transverse,.

<Desc / Clms Page number 21> c) the outer surface of this mandrel being curved both longitudinally and transversely so as to form continuous surfaces of composite curvature on the front end and on the rear end of the mandrel, d) this mandrel being arranged so as to. swing into the forming passage so that its composite curved outer rear surface gradually contacts the outer wall of the leading end of the next blank from the end of that blank and back to the part median of it, so as to support this wall and to prevent it from flattening during the formation of the elbows.

12. A following machine 11 in which said mandrel carries an annular collar on its middle part, which collar is respectively seated on the front end and the rear end of two successive blanks.

13. For use in an apparatus for forming elbows from rectilinear tubular blanks, a free mandrel comprising: a) an elongated body in the general shape of a ring segment, arranged to enter into the adjacent blanks and support their walls; b) the inner surface of the body of this mandrel being rectilinear in the longitudinal direction but curved transversely, c) and the outer surface of the body of this mandrel being curved both longitudinally and transversely so as to form continuous outer surfaces front and rear with composite curvature. <Desc / Clms Page number 22>

14. For use in an apparatus intended for forming bends starting from rectilinear tabular blanks, a mandrel comprising: a) a body arranged to penetrate into the front end of a blank to be shaped and to form. support, b) and a stopper placed on this body and on which sits the front end of a blank, c) the body of the mandrel having a shape allowing it to gradually support the outer wall of the blank from the front end thereof back and to the middle part of this blank during elbow formation.

In an apparatus for forming elbows from reotilinear tubular blanks; a) a device for advancing a blank along an enclosed path b) a device supporting the rear part of the blank and preventing it from sagging in its movement on said path., c) and a rigid device arranged so to be able to be placed in the front end of a blank, said device having a shape making it progressively come into contact with the outer wall of the front part of the blank between the end of this blank, behind and up to the middle part of said blank, and preventing this wall from sagging during the movement of the blank along said path.

16. A next machine 15, and comprising a device supporting a front end of the inner wall of a blank and constantly preventing it from sagging during the movement of this blank on said embedded path. <Desc / Clms Page number 23>

17. An apparatus for forming an elbow from a rectilgen tubular blank having a rear end of irregular cut forming an outer part perpendicular to its axis and an inner part inclined on this axis; a) a device making it possible to move this blank along a curved path so as to put it in the form of an elbow, b) this device comprising an orqane in contact with the rear end of the blank, c) this member having tooth-shaped parts which gradually penetrate into the blank as the metal flows during shaping.

13, In a device for the formation of elbows starting from rectilgfe tubular blanks; a) a device for moving a blank along a circular path so that its outer wall tends to elongate, b) and a device constraining the ends of this outer prong so as to significantly reduce its elongation during movement of the blank along said circular path, this device comprising! 1) a first member which can come into contact with the rear face of this outer wall, 2) a second member shaped so as to come into longitudinal contact with the front face of this outer wall, 3)

these two members moving together and with the blank without changing their relative positions during the shaping of this blank. <Desc / Clms Page number 24>

19, A machine according to paragraph 13 Jans which the blank and said members are constructed and arranged so that the inner wall of the blank is not under stress longitudinally.

20. In an apparatus for forming elbows starting from rectilinear tabular shoulders a) a mold forming a curved bearing surface receiving the wall of the blank to form the inner radius of the elbow, b) a plunger capable of come into contact with the rear end of a blank, said plunger moving in a rectilinear movement, c) a first mandir- connected to this plunger and which can come to be placed in the rear end of the blank for the supporting, d) an organ which can come into contact with the front end of the blank and moves in a curved path around the center of said surface, e)

and a second mandrel separates duprmeior. fixed on said member and being able to come to be placed inside the front end of the blank to support it and this second mandrel siutenant by one of its parts Ja front outer surface -: the abouche.

21. A next machine 20, comprising a device xonected to said member and resistant, all yielding, to the monvein of ect brgane when a blank is in the process of setting one firne ytiry of said support surface due to the plonerur movement .

22. A next machine 20, comprising a recoil forming member Dce moving in a rectili'-jne movement with said plunger and carrying a qorge supporting the rear end of 3. ' blank during its formatting. <Desc / Clms Page number 25>

23. In an apparatus for forming elbows starting from rectilinear sketches? a) a mold forming a curved support surface receiving the wall of the blank on its part to form the inner radius of the bend, b) a plunger which can come into contact with the rear end of a blank, is diver replacing with a rectic movement, C) a first mandrel fixed to said plunger and which can come inside the rear end of the blank to support it, d) a member which can come to be placed against the front end of the blank carrying a groove, and able to move on a curved path around the center of said curved surface, e)

and a second mandrel rigidly fixed inside said groove and, consequently, distant from said member, f) this second mandrel being arranged to be able to be capped by the front end of the blank so that this front end - Is housed 4 inside said groove and supported by the wall thereof, the second mandrel having a shape such that it gradually comes into contact with the outer wall of the blank starting from the end before this floor back and up to the middle part of it.

24. In a machine for cooling a length of tube in the form of an elbow, a rotating forming cylinder bearing. a curved peripheral groove, a sub-assembly of a pressure mandrel comprising a part which can be introduced into, and a part pushing on, the end of a tubular part to be formed and moving in a straight line while holding this part in the rotary forming groove, a front mandrel sub-assembly, part of which can be inserted into, and a <Desc / Clms Page number 26> part applies end pressure to a part, and e moving] following a curved path around the axis of,

forming cylinder rotating while maintaining the part in the barge of this cylinder, the parts of the two mandrels introduced into the part being formed, remaining there and moving with this part during its shaping, and a resistant energy device, while yielding to the movement of the rotary forming cylinder and the front mandrel during the elbow forming action and returning them to their original position after ejection of the formed part.

23, A machine according to 24, in which the pressure randirn sub-assembly moves in a straight line parallel to a tangent to the throat of the rotary forming cylinder, this sub-assembly being mounted and moving on a circular arc around the rotary forming cylinder.

26. A following machine 24, in which the mandrel sub-assemblies each comprise a mandrel which is received in the part and a sleeve which engages at the end of this part, this manidin applying a part of its cylindrical surface to the part to be bending inside the groove of the rotary forming cylinder to form the wall corresponding to the inner radius of the elbow, and the front mandrel having a curved portion with composite curvature shaping the wall corresponding to the outer radius of the elbow, setting in the form of the inner radius and that of the outer radius of the elbow being simultaneous.

27. A following machine 24, in which the subassemblies of mandrels each comprise a mandrel which is housed in the place to be formed and a sleeve which bears at the end on this part, these sleeves being cut in <Desc / Clms Page number 27> bevel on their end so as to come into oblique contact with the part to be bent but only on the inner parts of the ends of the part to be bent at a distance from the outer wall of the elbow, this outer wall of the part being longer than the inner wall and the metal on this inner wall flowing into the space left free by the sleeves., 28.

A following machine 24, in which the energy device is actuated by a pressurized fluid and is provided with a control device making it possible to rotate the rotary forming cylinder and the front mandrel so as to return them to their initial position after withdrawal of the pressure mandrel in its initial position, 29, In a machine for cooling a length of tube in the form of an elbow, a rotary forming cylinder carrying a curved peripheral groove, a pressure mandrel sub-assembly having a portion capable of being seated. '' insert into, and a part pushing on, the end of a part and moving in a straight line while maintaining the part in the rotary forming groove,

a support movable with the pressure mandrel and carrying a groove receiving the part to be bent, a front mandrel sub-assembly, part of which can be inserted into, and part applies pressure at the end, on the part, is moving along a curved path and holding the part in the groove of the rotating forming cylinder, and a resisting energy device, while yielding, to the movement of the rotating forming cylinder in one direction and capable of rotating this cylinder in the other direction, 30, In a process for placing lengths of metal tubes in the form of elbows,

the operations consisting in cutting the ends of these lengths of tubes so <Desc / Clms Page number 28> to provide on the outer radius of the bend surfaces perpendicular to the axis and oblique surfaces with respect to this axis, this section being such that the area of the inclined surfaces is greater on the rear end of the tube than on its end before so as to allow a greater flow of the metal towards the rear end of the tube during its shaping to introduce the tube in a cylindrical passage whose inside radius and outside radius depend on the dimensions of the length of tube 4 train to place the front end of the tube on a mandrel that can move with the tube following the curve

formed by the passage; 1 and exerting pressure on the part of the rear end of the tu. that an erpendicular to the axis thereof so as to forcibly pass the tube and mandrel in the curved passage while supporting the outer wall of the tube, gradually, starting from its front end, back and up 'to the middle part of the tube.

31. In a process for placing rectilinear tubular blanks in the form of elbows, the operations of: a) cutting a blank so that each of its ends is flat on the outside and the inside parts of each of these ends are oblique with respect to the axis of the blank, the angle of inclination of the front end on this axis being greater than the angle of inclination of the rear end, b) set up a blank so that it can move in a circular path, c) place the front end of the blank on a mandrel <Desc / Clms Page number 29> d) and causing the blank and the mandrel to move together along this curved path by pressure initially exerted on the part perpendicular to the axis of the rear end of the blank, then,

gradually on the inclined part of this rear end.

32. A method according to 31, comprising the operation of keeping the outer wall of the blank under compression during its movement on the circular path.

31. In a process for placing straight tubular blanks into a bend, the steps of: a) preparing a tubular blank for movement in a curved path, b) placing a mandrel on the tube. 'before the front end of this tubular blank, c) positioning said front end of the blank around the mandrel, d) and moving the blank and the mandrel together along said curved path by exerting a pressure on the rear end of the blank while maintaining longitudinal stress on the outer wall of the blank. at 34.

In a process for placing rectilinear tubular blanks in the form of an elbow, the operations consisting in a) preparing a tubular blank to make it move in a rectilinear path, b) placing a mandrel on the front of the end before this tubular blank, c) place said front end of the blank <Desc / Clms Page number 30> around the mandrel, d) to move the blank and the mandrel together along said path by exerting pressure on the rear end of the blank, e) and to keep the outer wall of the blank under compression constantly longitudinal while moving the blank along a curved path.

35. The following method 34 and comprising the operation of keeping the inner wall of the blank free from any longitudinal stress during said movement of this blank.

3b, In a process for placing rectilinear tubular blanks in the form of an elbow, the operations consisting in: a) preparing two tubular blanks to make them move in succession along a rectilinear path, b) placing the front end d 'an elongated mandrel and the rear end of the first blank so that the mandrel fits inside this blank, c) positioning the rear end of this mandrel and the front end of the second blank so that the mandrel fits inside this second blank, d) and to move the two blanks and the mandrel together along the said curved path by exerting pressure on the rear end of the second blank.

37, In a process for placing rectilinear tubular blanks in the form of elbows, the operations consisting of; a) prepare a tubular blank to move it along a curved path, b) position a mandrel having the general form] 3 of a <Desc / Clms Page number 31> segment of a circle and having a composite curved outer surface conforming to the outer pjroi of the desired bend on the front of the front end of this blank, c) place the front end of the blank around the mandrel , d) moving the blank and the mandrel together along said curved path by exerting pressure on the rear end of the blank, e) and allowing the mandrel to tilt during its curved movement along with the 'draft,

so that its exterior surface with composite curvature progressively supports the exterior wall of said blank from its front end, behind it and to the middle part of this blank, and prevents it from sagging.

38. In a method of placing rectilinear tubular blanks in the form of elbows, the operations consisting of; a) position the blank so that it can move along a circular path, b) and move this blank along this path while simultaneously supporting the outer p-king of the blank gradually from its end forward, backward and up to its middle part, to prevent it from sagging.

39. The following method 38 and comprising the step of supporting the front end of 1-. inner wall of the blank to prevent it from sagging, during the movement of the blank following 'In said circular path, 40. In a method of placing rectilinear tubular blanks in the form of elbows, the operations consisting at:

<Desc / Clms Page number 32> a) prepare a blank for movement in a curved path, b) place the front end of this blank on a first mandrel, c) place a second mandrel inside the rear end of the blank , d) and moving the blank and the two mandrels together along said curved path by exerting pressure on the rear end of the blank while maintaining longitudinal stress on the outer wall of the blank.

41. The following method 4, and comprising the operation of opposing a resistance to the joint movement of the blank and the mandrels, while yielding to co movement.