BE652654A

BE652654A -

Info

Publication number: BE652654A
Application number: BE652654A
Authority: BE
Priority date: 1964-09-03
Filing date: 1964-09-03
Publication date: 1965-03-03

Description

  

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  Sac et procédé et appareil pour le confectionner. 



   La présente invention concerne des récipients et, plus particulièrement, des perfectionnements apportés à des sacs qui sont confectionnés en partant de matières plastiques en feuillet flexibles, ainsi   que,des   procédés et des appareils pour les confec- tionner. 



   La présente invention a   notamment   pour buts de procurer: un sac bâti de façon perfectionnée ainsi qu'un procédé et un appareil pour le confectionner, où une matière plastique en feuille flexible est.pliée, soudée et coupée de manière à formér, lorsqu'elle est   séparée,   plusieurs ébauches de sac tubulaires   ouver-   tes à une extrémité èt fermées à l'autre par les opérations de pliage ou de soudage ,de manière à avoir un fond carré;

   un sac ainsi qu'un procédé et un appareil pour le   confec-   

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 tionner, où une feuille de matière flexibleappropriée est initiale-   zaent   pliée en un tube aplati qui est ensuite divisé en ébauches de sac fermées chacune à une   extraite,   chaque ébauche étant ouverte sur un mandrin et l'extrémité fermée étant transformée de manière à donner au sac un fond carré, un sac ainsi qu'un procédé et   un.appareil   pour le   confec-   tionner, où un tronçon de tube aplati est soudé transversalement à une extrémité puis ouvert sur un mandrin de manière à pouvoir   effectuer   des soudures supplémentaires dans'la matière du fond afin de donner au sac un fond carré;

   un procédé et un appareil pour confectionner des sacs, où   l'on   transforme une matière en feuille flexible en éléments ou      ébauches   tubulaires,'une   extrémité de chaque ébauche étant aplatie et fermée par une soudure ou un pli transversal, on ouvre chaque ébauche tubulaire de manière à former un corps de sac de section rectangulaire et un fond à l'extrémité fermée de l'ébauche tubulai- re comportant des sections d'extrémité triangulaires qui s'éten- dent   à   l'extérieur des côtés opposés du sac, on fait des soudures dans les sections triangulaires aux bords inférieurs des côtés du sac de manière à former un fond carré et en-enlève les parties d'extrémité qui se trouvent à l'extérieur des zones soudées;

     '   un procédé pour fabriquer un sac-suivant lequel on soude transversalement une extrémité d'un   élément ou   ébauche tubulaire en matière flexible, on ouvre l'ébauche tubulaire de manière à for- mer un corps de'section rectangulaire, on plie les parties de   l'ébauche   tubulaire situées à l'extrémité soudée et destinées à former le fond dans un plan transversal ce qui donne des sections d'extrémité triangulaires qui s'étendent dans le plan du fond et à l'extérieur des côtés opposés, on soude   les bords   intérieurs des sections triangulaires de manière à obtenir un fond carré et on enlève les sections triangulaires qui se trouvent à l'extérieur des bords soudés;

   un sac confectionné où une ébauche de sac tubulaire est formée avec une extrémité fermée, l'ébauche' tubulaire est glissée 

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 sur un mandrin dilatable, le mandrin est dilaté et l'ébauche tubu- laire est ouverte de manière à former un corps de section rectan- gulaire et des parties à l'extrémité fermée destinées à former le fond qui sont rempliées dans un plan transversal à l'extrémité du mandrin ce qui donne des sections pliées triangulaires qui   s'éten-   dent dans le plan du fond etlatéralement par rapport aux faces latérales ou côtés opposés du mandrin, les sections.triangulaires étant soudées le long des bords d'extrémité inférieurs des faces latérales du mandrin et leurs parties qui s'étendent à l'extérieur des lignes de soudure étant sectionnées pour former un fond carré ;

   un sac confectionné où un tube de matière est soudé transversalement à une extrémité le tube soudé est glissé sur un mandrin dilatable, le mandrin est dilaté et le corps du tube est ouvert de manière à présenter une section rectangulaire et des par- ties destinées à former le fond adjacentes à la soudure transver- sale sont repliées dans un plan transversal à l'extrémité du man- drin ce qui donne des sections triangulaires pliées qui s'étendent dans le plan du fond et latéralement par rapport aux faces latera- les opposées du mandrin, les sections triangulaires étant soudées le long des bords d'extrémité inférieurs des faces latérales du mandrin et   finalement   les sections triangulaires qui s'étendent à l'extérieur des lignes de soudure sont sectionnées pour former un fond carré;

   un appareil pour confectionner des sacs en une pellicule de matière plastique flexible soudable à chaud qui comprend un mécanisme servant à plier longitudinalement une nappe continue de la matière sous forme d'un tube aplati, un mécanisme pour souder le tube à chaud afin d'y former des soudures espacées, un méca- nisme pour sectionner le tube soudé en ébauches de sac dont une extrémité est fermée, un mécanisme pour amenpr les ébauches à des mandrins dilatables montés sur un bâti rotatif, un mécanisme pour dilater les mandrins et équarrir chaque ébauche de sac pour former un corps de section rectangulaire et un fond carré comportant des sections triangulaires saillantes pliées de chaque côté, un méca- 

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 nisme   pou-1,

     souder à chaud les sections triangulaires pliées le long des bords du fond et pour sectionner les parties des sections qui font saillie à l'extérieur des soudures ainsi formées et un mécanisme pour décharger les sacs achevés des mandrins et les   transférer   à une machine de remplissage et de fermeture automatique 
 EMI4.1 
 ou à un autre mécanie4e de traiteaent;

   un appareil servant à confectionner des sacs à partir d'une pellicule de matière plastique flexible soudable à chaud qui comprend un mécanisme servant à plier longitudinalement une nappe continue de la matière en un tube .aplati continu, un méca-   nisme   pour souder à chaud les bords latéraux chevauchants afin de former une soudure longitudinale, un mécanisme pour souder trans=   versalement   le tube à des intervalles déterminés, un mécanisme pour sectionner le tube en ébauches de sac comportant chacune une extrémité soudée   transversalement   un mécanisme pour amener les ébauches successivement à des mandrins dilatables montes sur une tourelle,

   un mécanisme   associé la   tourelle pour dilater les man- drins et équarrir chaque ébauche afin de former un corps de sec- tion rectangulaire et un fond carré comportant des sections triangulaires saillantes pliées de chaque côté, un mécanisme égale- ment associé à la tourelle pour souder à chaud les sections tri- angulaires pliées le long des bords du fond et pour sectionner les parties des sections qui font saillie à l'extérieur des soudures ainsi formées et un mécanisme pour décharger les sacs achevés et ouverts des mandrins. 



   Ces buts et avantages de l'invention ainsi que d'autres encore ressortiront de la description donnée ci-après, à titre d'exemple avec référence aux dessins annexés dans   lesquels : ,   .la Fig. 1 est une vue en élévation schématique d'un appa- reil servant à confectionner un sac suivant l'invention; là Fig. 2 est une vue en plan de l'appareil de la Fig.l, largement schématique et en partie .arrachée; la Fig. 3 est une vue suivant la ligne 3-3 de la Fig.l, à plus grande échelle, de l'extrémité inférieure d'une ébauche de sac 'placée sur un mandrin conformateur dilaté;

   

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 la Fig.   4-   est une vue suivant la ligne   4-4   de la Fig.l, à plus grande échelle, de l'extrémité inférieure d'une ébauche de sac qui a été aplatie contre l'extrémité du mandrin conformateur et soudée; la Fig. 5, est une vue suivant la ligne 5-5 de la Fig.l, à plus grabde échelle, montrant l'opération de sectionnement finale qui achève le fond du sac; la Fig. 6'est une coupe fragmentaire suivant la ligne 6-6 de la Fig. 5, à plus grande échelle; la fig. 7 est une vue en perspective, en partie arrachée, montrant le sac achevé et ouvert; la Fig.   3.est   une vue en perspective, en partie arrachée, montrant le sac achevé et aplati;

   la Fig. 9 est une vue en élévation de côté, en partie arrachée, de la tourelle porte-mandrin représentée sur la Fig. l, à plus grande   échelle,   la Fig. 10 est une vue en plan de la tourelle porte- mandrin de la Fig. 9, certaines parties de la tourelle étant arra-   chées   et d'autres omises; la Fig. 11 est une coupe suivant   la,   ligne 11-11 de là Fig. 10,' ' la Fig. 12 est une vue en plan schématique d'un appareil servant à fabriquer une variante du sac; la Fig. 13 est une vue en élévation de côté de   l'appa-   reil de la Fig. 12, en substance suivant la ligne 13-13 de la Fig. 12; la Fig.   14   est une vue en élévation de côté de l'appa- reil de la Fig.   12,   en substance suivant la ligne   14-14   de la Fig. 



  12; la Fig. 15 est une   vue'en   perspective du sac modifié ouvert ;   et,   la Fig. 16 est une vue en perspective du fond du sac modifié   replié   et aplati, à une échelle légèrement réduite. 



   La confection du sac 10, qui est représenté achevé et 

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 ouvert sur la Fig. 7 ressortira clairement de la description du procédé et de l'appareil utilisé pour le confectionner,   l'appareil   étant représenté schématiquement sur les Figs. 1 et 2. Le sac est confectionné en partant d'une nappe 11   d'une   matière appropriée telle qu'une pellicule de polyéthylène relativement   mince.   Une nappe de matière plastique continue 11., provenant d'un rouleau d'alimentation ou d'une autre source, est transformée en un tube par un dispositif de pliage de construction classique, comme indi- qué en 12, et une soudure longitudinale   13'est   formée dans le tube en réunissant les bords chevauchants de la'pellicule.

   Cette opéra-      tion peut être exécutée par un galet de soudage à chaud 14 coopé- rant avec une plaque à souder intérieure 15 et un contre-galet 14'. 



   Le tube aplati 16 ainsi formé est ensuite soudé transversalement en 
17 à des endroits longitudinalement espacés par des fers à souder à mouvement de va-et-vient 18 et 18' fonctionnant par intermitten-   ce.   Le tube aplati et soudé 16 est avancé vers une barre porte- couteau où des lames de cisaille 19 et   19']qui   sectionnent le tube près des soudures transversales 17 le divisent en ébauches du sac successives 20 de dimensions égales. 



   Chaque ébauche de sac successive 20 est ensuite avancée entre des paires latéralement espacées de courroies d'alimentation coopérantes 21 .et   21'   et est glissée sur   l'un   de plusieurs man- drins contractés 22 qui sont montés périphériquement à une certaine distance les uns des autres sur une roue ou tourelle 23 qui tourne sur un arbre 23'. L'extrémité avant ou embouchure de chaque ébau- che de sac 20 est ouverte de manière à   s'engager   sur le mandrin contracté 22, par deux bras suceurs pivotants 24, 24' qui sont actionnés pour saisir les côtés de l'ébauche de sac près de son extrémité avant et pour s'écarter ensuite d'une distance prédéter- minée, suffisante pour recevoir le mandrin, et qui peuvent égale- ment avancer avec l'ébauche pour contribuer à l'enfiler sur le mandrin.

   Chaque mandrin 22 comprend deux plaques rectangulaires qui sont   écartées   l'une de l'autre pour dilater le mandrin après qu'il a reçu l'ébauche de sac par un mécanisme approprié lorsque 

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 la tourelle 23 tourne de manière à ouvrir l'ébauche. 



   L'ouverture de l'ébauche 20 donne au corps de l'ébauche une section rectangulaire et la partie 25 (Fig. 3) de l'ébauche destinée à former le fond du sac se plie automatiquement à plat contre l'extrémité extérieure du mandrin de manière à se placer dans un plan transversal à   l'axe   longitudinal du mandrin, des sections d'extrémité triangulaires pliées 26 et   26'   faisant saillie à l'extérieur des côtés du mandrin.

   Des soudures transversales 27 et   27'   (Fig.   4)   sont formées dans les parties pliées 26 et 26' par des fers à souder à mouvement de va-et-vient indiques en 28 et des platines mobiles coopérantes 28' (Fig. 1).Les parties extérieu- res des sections triangulaires 26 et 26' sont alors rognées ou sectionnées et évacuées au poste suivante comme   indique   par la Fig. 5, par des couteaux rogneurs à mouvement de va-et-vient   29   et des platines coopérantes 29' et on obtient ainsi un fond 25 rectan- gulaire ou carré dans lequel la ou les soudures 27, 27' délimitent les bords inférieurs des deux côtés latéraux opposés 30 et 30' résultant de l'équarrissage du corps du sac sur le mandrin 22. 



  Les soudures marginales 27 et 27' s'étendent légèrement vers l'ex- térieur des bords inférieurs des côtés latéraux 30 et 30', comme le montrent les Figs. 6 et 7. 



   Lorsqu'il est équarri comme le montre la Fig. 1 on éjecte le sac 10 de la tourelle 23 en contractant le mandrin 22 et en déplaçât le sac arialement vers l'extérieur dans un sens radial s'écartant du mandrin. Le sac fini peut alors être soufflé du mandrin ou bien un dispositif de démandrinage quelconque approprié peut être utilisé pour enlever le sac. Le sac peut alors être utilisé pour emballer des marchandises dans son état équarri et ouvert final,   et, à   cet effet, on le remplit de marchandises et on le soude convenablement à son extrémité supérieure pour   ferzser   son embouchure ouverte.

   L'appareil peut être utilisé avec une machine à remplir et à fermer les sacs et des moyens peuvent être prévus, comme le montre la Fig. 1, pour décharger les sacs dans une trémie indiquée en 31 qui les guide pour les déposer par gravité ou par 

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 dépression dans un   alvéole   32 d'un transporteur en mouvement 33 'dans lequel les sacs sont remplis et fermés par des mécanismes appropriés. 



   En variante, les sacs 10 peuvent être enlevés des man- driris 22 pour être décharges horizontalement sur une plate-forme 
34 indiquée en traits pointillés sur la Fig. 1. Les sacs peuvent être avancés de la plate-forme   34   vers une machine de remplissage et de fermeture ou vers n'importe quel autre appareil servant à exécuter d'autres opérations sur les   sacs.   



   Si on désire emmagasiner les sacs pendant un certain 'temps après les avoir enlevés des mandrins 22 ou si on désire accumuler une certaine quantité de sacs en une pile, on peut plier chaque sac et aplatir son fond comme indique sur la Fig. 8. 



   A cet effet, il suffit d'aplatir   simultanément   le corps du sac et   e   fond 25, les côtés   30,   30' et 35, 35' étant aplatis ou repliés de manière \ amener la soudure longitudinale 13 sur une ligne de pliage médiane prévue dans la paroi latérale 35 qui devient le bord 36 du corps aplati. Le fond 25 est plié dans le plan d'une paroi latérale 34 de façon que la soudure   17   s'étende dans le sensde l'axe longitudinal du corps du sac et que les parties infé- rieures des parois latérales 35 et 35' se plient dans le plan du fond 25 le long des lignes 37, 37' et 38, 38' qui vont des extré- mités des soudures 27, 27' aux extrémités des plis marginaux 36, 
36'.

   Les plis latéraux 39 et 39' initialement formés dans le fond et les plis d'angle initiaux   40   et   40'   sont indiqués en traités pointillés sur la Fig. 8. 



   L'appareil représenté sur les Figs. 1 et 2 est pourvu de rouleaux d'alimentation coopérants   41,     42,     43   et 44 ou de dispositifs d'alimentation analogues servant à faire avancer la nappe et les ébauches de sac vers des postes de travail successifs et ces dispositifs d'alimentation ensemble avec les dispositifs de   oudure   et de sectionnement sont montés sur un bâti de support approprié et sont actionnés par des mécanismes d'entraîne- ment appropriés (aon représentés) qui y sont reliés. 

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   Le mécanisme de la tourelle 23   avçc   les appareils y associés servant à actionner les mandrins 22 est de préférence construit comme le montrent en détail les Figs. 9 à 11. Il comprend un   moyeu     45   monté sur l'arbre d'entraînement 23' dont l'extrémité tourillorne dans le palier   46.   Le moyeu 45 porte une couronne 47 qui comporte huit supports   48   espacés autour de sa périphérie pour .monter les mandrins dilatables 22. Chaque mandrin   22   comprend deux plaques rectangulaires mobiles l'une par rapport à l'autre 50 et 51. 



  Une plaque 50 est fixée sur une traverse 52 d'un support   48.   L'au- tre plaque 51 est fixée sur un coulisseau 53 qui comporte des rai- nures de guidage 54 et   54'   dans ses bords latéraux grâce auxquelles il peut coulisser sur deux rails de guidage tournés vers l'inté- rieur 55 et 55' qui sont prévus sur le support   48.   Le déplacement du coulisseau 53 sépare les plaques 50 et 51 tout en les maintenant parallèles l'une à   l'être.   Le coulisseau 53 est pourvu d'une rai- nure ou d'un chemin de came 56 sur sa face intérieure qui est per- pendiculaire au sens dans lequel il se déplace et qui reçoit un galet de came   57.   Le galet de came 57 est monté sur l'extrémité libre d'un bras de levier oscillant coudé en L 58.

   L'autre ' extrémité du levier de came 58 est attachée par un pivot 60 à un prolongement de support 61 sur le rail 55'. Le levier de came 58 porte un autre galet- de came 62 près du pivot 60 qui coopère avec le chemin de came   63 d'une   came   64.   La came 64 est fixée sur- un bâti fixe 65 sur lequel l'arbre 23 est monté. Le chemin de came 63 est façonné de manière à actionner le levier 58 pour déplacer la plaque mobile 51 du mandrin 22 dans un sens ou dans l'autre comme il le faut aux différents postes de travail situés dans le chemin du mandrin qui est entraîné dans un trajet circulaire par la rota- ' tion de l'arbre 23. Un ressort de traction 66 est relié en 67 au levier 58 et en 68 à une plaque 61 de manière à maintenir le galet de came 62 contre la cane 63. 



   Un tuyau d'air 70 est raccordé à une extrémité à un ajutage 71 et à l'autre extrémité à une ouverture 72 ménagée dans le moyeu 45 qui communique avec une boîte à vent 73 sur le bâti 

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 fixe 65 de manière à débiter un courant d'air dans le mandrin lorsque ce dernier atteint un poste de décharge des sacs et ainsi à éjecter le sac du mandrin. La boite à vent 73 est raccordée par le tuyau 74 à une arrivée d'air comprimé et peut être réglée pour assurer l'éjection du sac à n'importe quel point voulu. D'autres dispositifs d'éjection des sacs peuvent évidemment être utilisés pour enlever les sacs des mandrins lorsqu'ils sont achevés, 
Une variante du sac est représentée en 80 sur les Figs. 



    15 et     16.   Le sac est confectionné en partant d'une nappe 81 de pellicule de polyéthylène ou d'une matière plastique en feuille semblable qui est amenée à partir d'un rouleau d'alimentation à une barre de pliage (Fig.   12).   La barre de pliage 82 replie la nappe 81 sur   elle-même   .autour d'une ligne de pliage 'horizontale 83 de façon que les bords de la pellicule soient-décalés l'un de l'autre comme le montre le   desìn,,   un bord 84 s'étendant sur une courte distance vers l'extérieur de l'autre bord 85. Le tube aplati 86 ainsi formé est entraîné par des rouleaux 87 et   87'   vers un couteau chauffé 83 et un rouleau-enclume coopérant'88'.

   Le tube 86 est coupé et simultanément soudé par une soudure en cordon 89 à des intervalles logitudinalement espacés par le couteau 88 de manière à diviser 1a nappe en plusieurs ébauches de sac 90 qui comportent chacune des bords latéraux formés par des soudures en cordon 89 et une extrémité fermée le long de la ligne de pliage 83. 



   Chaque ébauche de sac successive 90 est avancée par les rouleaux d'alimentation 91 et 92 vers les courroies 93 et 94, le rouleau 95 étant monté sur un bras pivotant 96 de manière à faire avancer les ébauches de sac par intermittence entre les deux paires de courroies 93 et   94.   Les ébauches sont amenées par les courroies 93 et 94 dans une position appropriée pour' être déplacées   latéra-   lement par un mécanisme de transfert à angle droit qui comprend deux paires de segments coopérants 97, 9?'. et 98, 98'.

   Les seg- ments tournants 97, 97' et 98, 98'   écartent   les ébauches des cour- roies 93 et 94 et les amènent vers des paires de rouleaux d'ali- mentation   100   et 101 d'où elles sont amenées aux mandrins 22 sur la 

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 tourelle 23 par des rouleaux d'alimentation 44 et des courroies 
21, 21 de ,la façon décrite avec référence à la Fig. 1. Les mandrins 
22 sont dilatés et le fond du sac est formé de la même façon que celle décrite avec référence au sac 10.

   Les parties 102 des ébau- ches de sac 90 destinées à former le fond sont équarries sur le mandrin 22 et les sections   d'extrémité   triangulaires résultantes sont soudées transversalement par des organes de soudure de manière à former des soudures en cordon 103 et 103' comme le montre la Fig.   15,,   les parties saillantes des sections triangulaires pliées   étant   sectionnées de la même façon que celle décrite avec référence aux sections triangulaires 26 et 26' de la Fig. 5. 



   Si on désire replier les sacs après les avoir enlevés des mandrins 22 on peut les aplatir comme le montre la Fig. 16. 



  La partie formant le corps du sac est .aplatie de manière à repren- dre sa position initiale avant son montage sur les mandrins 22. 



  Les côtés latéraux   104   et 104' et les côtés d'about   105,   105' sont aplatis de manière à amener les soudures en cordon 89 le long des bords latéraux du corps. La partie 102 destinée à former le fond est repliée autour du bord inférieur 106 d'un côté latéral   104'     contre-le   côté opposé 104 ce qui donne des sections triangulai- l'eu inférieures des parois d'extrémité qui se plient dans le plan du fond 102 le long des lignes de pliage   107.,     107',   et 108, 108' qui vont des soudures d'extrémité-103 et 103' aux extrémités des plis marginaux. 



   Bien entendu, l'invention n'est en .aucune façon limitée aux détails de la construction qui précède, de nombreux change- ments et modifications pouvant en effet y être apportés sans sor- tir de son cadre.



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  Bag and method and apparatus for making it.



   The present invention relates to containers and, more particularly, to improvements to bags which are made from flexible sheet plastics, as well as to methods and apparatuses for making them.



   The present invention particularly aims to provide: a bag constructed in an improved manner as well as a method and apparatus for making it, wherein a flexible sheet plastic material is folded, welded and cut so as to form, when is separated, several tubular bag blanks open at one end and closed at the other by folding or welding operations, so as to have a square bottom;

   a bag and a method and apparatus for making it

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 tion, where a sheet of suitable flexible material is initially folded into a flattened tube which is then divided into closed bag blanks each with one extracted, each blank being opened on a mandrel and the closed end being processed to give the bag a square bottom, a bag and a method and apparatus for making it, where a flattened section of tube is welded transversely at one end and then opened on a mandrel so that further welds can be made in the bottom material to give the bag a square bottom;

   a method and apparatus for making bags, in which a flexible sheet material is converted into tubular elements or blanks, with one end of each blank being flattened and closed by a weld or transverse fold, each tubular blank is opened from so as to form a bag body of rectangular cross section and a bottom at the closed end of the tubular blank having triangular end sections which extend outward from the opposite sides of the bag, one makes welds in the triangular sections at the lower edges of the sides of the bag so as to form a square bottom and peel off the end portions which lie outside the welded areas;

     'a method of making a bag, in which one end of a tubular element or blank made of flexible material is transversely welded, the tubular blank is opened so as to form a rectangular section body, the parts are folded. the tubular blank located at the welded end and intended to form the bottom in a transverse plane which gives triangular end sections which extend in the plane of the bottom and outward from the opposite sides, the inner edges of the triangular sections so as to obtain a square bottom and the triangular sections which are outside the welded edges are removed;

   a made-up bag where a tubular bag blank is formed with a closed end, the tubular blank is slipped

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 on an expandable mandrel, the mandrel is expanded and the tubular blank is opened so as to form a body of rectangular section and portions at the closed end intended to form the bottom which are tucked in a plane transverse to the end of the mandrel resulting in triangular bent sections which extend in the plane of the bottom and laterally of the side faces or opposite sides of the mandrel, the triangular sections being welded along the lower end edges of the mandrel. side faces of the mandrel and their parts which extend outside the weld lines being cut to form a square bottom;

   a made-up bag where a tube of material is welded transversely at one end, the welded tube is slid over an expandable mandrel, the mandrel is expanded and the body of the tube is opened so as to present a rectangular section and parts intended to form the bottom adjacent to the cross weld are folded in a transverse plane at the end of the chuck resulting in folded triangular sections which extend in the plane of the bottom and laterally with respect to the opposite side faces of the core. mandrel, the triangular sections being welded along the lower end edges of the side faces of the mandrel and finally the triangular sections which extend outside the weld lines are sectioned to form a square bottom;

   an apparatus for making bags of a flexible heat-sealable plastic film which comprises a mechanism for longitudinally folding a continuous web of the material into a flattened tube, a mechanism for heat-sealing the tube therein forming spaced welds, a mechanism for cutting the welded tube into bag blanks with one end closed, a mechanism for feeding blanks to expandable mandrels mounted on a rotating frame, a mechanism for expanding the mandrels and squaring each blank bag to form a body of rectangular section and a square bottom comprising projecting triangular sections folded on each side, a mechanism

 <Desc / Clms Page number 4>

 louse-1 nism,

     heat sealing the folded triangular sections along the edges of the bottom and for severing the portions of the sections which protrude outside the welds so formed and a mechanism for unloading the completed bags from the mandrels and transferring them to a filling machine and automatic closing
 EMI4.1
 or to another processing mechanism;

   an apparatus for making bags from a flexible heat-sealable plastic film which comprises a mechanism for longitudinally folding a continuous web of the material into a continuous flattened tube, a mechanism for heat-sealing them overlapping side edges to form a longitudinal weld, a mechanism for transversely welding the tube at determined intervals, a mechanism for cutting the tube into bag blanks each having one end transversely welded a mechanism for feeding the blanks successively to mandrels expandable mounted on a turret,

   a mechanism associated with the turret for expanding the chucks and squaring each blank to form a rectangular section body and a square bottom having protruding triangular sections bent on each side, a mechanism also associated with the turret for welding heat the triangular sections folded along the edges of the bottom and for severing the portions of the sections which protrude outside the welds so formed and a mechanism for unloading the completed and opened bags from the mandrels.



   These objects and advantages of the invention as well as others will emerge from the description given below, by way of example with reference to the appended drawings in which: FIG. 1 is a schematic elevational view of an apparatus for making a bag according to the invention; there Fig. 2 is a plan view of the apparatus of FIG. 1, largely schematic and partly broken away; Fig. 3 is a view taken on line 3-3 of Fig. 1, on a larger scale, of the lower end of a bag blank placed on an expanded shaping mandrel;

   

 <Desc / Clms Page number 5>

 Fig. 4- is a view taken on line 4-4 of Fig.l, on a larger scale, of the lower end of a bag blank which has been flattened against the end of the shaping mandrel and welded; Fig. 5, is a view taken on line 5-5 of Fig.l, on a larger scale, showing the final severing operation which completes the bottom of the bag; Fig. 6 is a fragmentary section taken on line 6-6 of FIG. 5, on a larger scale; fig. 7 is a perspective view, partly broken away, showing the bag completed and opened; Fig. 3. is a perspective view, partly broken away, showing the completed and flattened bag;

   Fig. 9 is a side elevational view, partly broken away, of the mandrel turret shown in FIG. 1, on a larger scale, FIG. 10 is a plan view of the chuck holder turret of FIG. 9, some parts of the turret being cut off and others omitted; Fig. 11 is a section taken on line 11-11 from there in FIG. 10, '' Fig. 12 is a schematic plan view of an apparatus for making an alternative bag; Fig. 13 is a side elevational view of the apparatus of FIG. 12, substantially along line 13-13 of FIG. 12; Fig. 14 is a side elevational view of the apparatus of FIG. 12, substantially along line 14-14 of FIG.



  12; Fig. 15 is a perspective view of the modified bag opened; and, FIG. 16 is a perspective view of the bottom of the modified folded and flattened bag, on a slightly reduced scale.



   The making of bag 10, which is shown completed and

 <Desc / Clms Page number 6>

 opened in Fig. 7 will emerge clearly from the description of the method and of the apparatus used to make it, the apparatus being shown schematically in FIGS. 1 and 2. The bag is made from a web 11 of a suitable material such as a relatively thin polyethylene film. A continuous plastic web 11, from a feed roll or other source, is made into a tube by a folding device of conventional construction, as shown at 12, and a longitudinal weld 13. 'is formed in the tube by joining the overlapping edges of the film.

   This operation can be carried out by a hot weld roller 14 cooperating with an inner weld plate 15 and a counter roller 14 '.



   The flattened tube 16 thus formed is then welded transversely in
17 at longitudinally spaced locations by reciprocating soldering irons 18 and 18 'operating intermittently. The flattened and welded tube 16 is advanced towards a knife bar where shear blades 19 and 19 '] which cut the tube near the transverse welds 17 divide it into successive bag blanks 20 of equal dimensions.



   Each successive bag blank 20 is then advanced between laterally spaced pairs of cooperating feed belts 21 and 21 'and is slid over one of several contracted mandrels 22 which are mounted peripherally spaced apart from each other. others on a wheel or turret 23 which turns on a shaft 23 '. The front end or mouth of each bag blank 20 is opened so as to engage the contracted mandrel 22, by two pivoting suction arms 24, 24 'which are operated to grip the sides of the bag blank. near its front end and then move away a predetermined distance sufficient to receive the mandrel, and which can also advance with the blank to help thread it onto the mandrel.

   Each mandrel 22 includes two rectangular plates which are spaced apart to expand the mandrel after it has received the bag blank by an appropriate mechanism when

 <Desc / Clms Page number 7>

 the turret 23 rotates so as to open the blank.



   The opening of the blank 20 gives the body of the blank a rectangular section and the portion 25 (Fig. 3) of the blank for forming the bottom of the bag automatically folds flat against the outer end of the mandrel. so as to lie in a plane transverse to the longitudinal axis of the mandrel, with folded triangular end sections 26 and 26 'projecting outward from the sides of the mandrel.

   Transverse welds 27 and 27 '(Fig. 4) are formed in the bent portions 26 and 26' by reciprocating soldering irons indicated at 28 and cooperating movable plates 28 '(Fig. 1) The outer parts of the triangular sections 26 and 26 'are then trimmed or sectioned and evacuated to the next station as indicated by FIG. 5, by reciprocating trimming knives 29 and cooperating plates 29 'and a rectangular or square bottom 25 is thus obtained in which the weld (s) 27, 27' delimit the lower edges on both sides. opposite sides 30 and 30 'resulting from the squaring of the body of the bag on the mandrel 22.



  The marginal welds 27 and 27 'extend slightly outward from the lower edges of the lateral sides 30 and 30', as shown in Figs. 6 and 7.



   When it is squared as shown in Fig. The bag 10 is ejected from the turret 23 by contracting the mandrel 22 and moving the bag therefrom arially outwardly in a radial direction away from the mandrel. The finished bag can then be blown from the mandrel or some suitable demander device can be used to remove the bag. The bag can then be used to pack goods in its final squared and opened state, and for this purpose it is filled with goods and suitably welded at its upper end to seal its open mouth.

   The apparatus can be used with a bag filling and sealing machine and means can be provided, as shown in FIG. 1, to unload the bags in a hopper indicated at 31 which guides them to deposit them by gravity or by

 <Desc / Clms Page number 8>

 depression in a cell 32 of a moving conveyor 33 'in which the bags are filled and closed by suitable mechanisms.



   Alternatively, the bags 10 can be removed from the mandiris 22 to be discharged horizontally onto a platform.
34 shown in dotted lines in FIG. 1. The bags may be advanced from platform 34 to a filling and closing machine or to any other apparatus used to perform other operations on the bags.



   If it is desired to store the bags for a period of time after removing them from the mandrels 22 or if it is desired to accumulate a certain amount of bags in a stack, each bag can be folded and its bottom flattened as shown in FIG. 8.



   To do this, it suffices to simultaneously flatten the body of the bag and the bottom 25, the sides 30, 30 'and 35, 35' being flattened or folded so as to bring the longitudinal weld 13 on a central fold line provided in the side wall 35 which becomes the edge 36 of the flattened body. The bottom 25 is folded in the plane of a side wall 34 so that the weld 17 extends in the direction of the longitudinal axis of the body of the bag and the lower parts of the side walls 35 and 35 'fold. in the plane of the bottom 25 along lines 37, 37 'and 38, 38' which go from the ends of the welds 27, 27 'to the ends of the marginal folds 36,
36 '.

   The side folds 39 and 39 'initially formed in the bottom and the initial corner folds 40 and 40' are shown in dotted lines in FIG. 8.



   The apparatus shown in Figs. 1 and 2 is provided with cooperating feed rollers 41, 42, 43 and 44 or similar feed devices for advancing the web and the bag blanks to successive work stations and these feed devices together with the sealing and severing devices are mounted on a suitable support frame and are actuated by suitable drive mechanisms (aon shown) connected thereto.

 <Desc / Clms Page number 9>

 



   The turret mechanism 23 with associated apparatus for actuating the mandrels 22 is preferably constructed as shown in detail in Figs. 9 to 11. It comprises a hub 45 mounted on the drive shaft 23 ', the journal end of which in the bearing 46. The hub 45 carries a ring 47 which has eight supports 48 spaced around its periphery for mounting them. expandable mandrels 22. Each mandrel 22 comprises two rectangular plates movable relative to each other 50 and 51.



  A plate 50 is fixed to a cross member 52 of a support 48. The other plate 51 is fixed to a slide 53 which has guide grooves 54 and 54 'in its lateral edges by which it can slide on. two inwardly facing guide rails 55 and 55 'which are provided on the support 48. The movement of the slide 53 separates the plates 50 and 51 while keeping them parallel to each other. The slider 53 is provided with a groove or a cam track 56 on its inner face which is perpendicular to the direction in which it moves and which receives a cam roller 57. The cam roller 57 is mounted on the free end of an L-angled swinging lever arm 58.

   The other end of the cam lever 58 is attached by a pivot 60 to a support extension 61 on the rail 55 '. The cam lever 58 carries another cam roller 62 near the pivot 60 which cooperates with the cam track 63 of a cam 64. The cam 64 is fixed to a fixed frame 65 on which the shaft 23 is mounted. . The cam track 63 is shaped so as to actuate the lever 58 to move the movable plate 51 of the mandrel 22 in one direction or the other as required at the various workstations located in the path of the mandrel which is driven in. a circular path through the rotation of the shaft 23. A tension spring 66 is connected at 67 to lever 58 and at 68 to a plate 61 so as to hold the cam follower 62 against the cane 63.



   An air pipe 70 is connected at one end to a nozzle 71 and at the other end to an opening 72 formed in the hub 45 which communicates with a wind box 73 on the frame.

 <Desc / Clms Page number 10>

 fixed 65 so as to deliver a current of air in the mandrel when the latter reaches a discharge station for the bags and thus to eject the bag from the mandrel. The air box 73 is connected by the pipe 74 to a compressed air inlet and can be adjusted to ensure the ejection of the bag at any desired point. Other bag ejection devices can obviously be used to remove the bags from the chucks when they are finished,
A variant of the bag is shown at 80 in Figs.



    15 and 16. The bag is made from a web 81 of polyethylene film or similar sheet plastic material which is fed from a supply roll to a folding bar (Fig. 12). . The fold bar 82 folds the web 81 back on itself around a horizontal fold line 83 so that the edges of the film are offset from each other as shown in the design. edge 84 extending a short distance outward from the other edge 85. The flattened tube 86 thus formed is driven by rollers 87 and 87 'towards a heated knife 83 and a cooperating anvil roll' 88 '.

   Tube 86 is cut and simultaneously welded by bead weld 89 at logitudinally spaced intervals by knife 88 so as to divide the web into several bag blanks 90 which each have side edges formed by bead welds 89 and one. closed end along fold line 83.



   Each successive bag blank 90 is advanced by the feed rollers 91 and 92 towards the belts 93 and 94, the roller 95 being mounted on a pivoting arm 96 so as to advance the bag blanks intermittently between the two pairs of Belts 93 and 94. The blanks are brought by belts 93 and 94 into a position suitable for being laterally moved by a right angle transfer mechanism which includes two pairs of cooperating segments 97, 9 ”. and 98, 98 '.

   The revolving segments 97, 97 'and 98, 98' separate the blanks from the belts 93 and 94 and bring them to pairs of feed rollers 100 and 101 from where they are fed to the mandrels 22 on. the

 <Desc / Clms Page number 11>

 turret 23 by feed rollers 44 and belts
21, 21 of, as described with reference to FIG. 1. The chucks
22 are expanded and the bottom of the bag is formed in the same way as described with reference to bag 10.

   The portions 102 of the bag blanks 90 for forming the bottom are squared on the mandrel 22 and the resulting triangular end sections are transversely welded by weld members to form bead welds 103 and 103 'as. shown in FIG. 15, the protrusions of the folded triangular sections being sectioned in the same manner as described with reference to the triangular sections 26 and 26 'of FIG. 5.



   If it is desired to fold up the bags after removing them from the mandrels 22, they can be flattened as shown in FIG. 16.



  The portion forming the body of the bag is flattened so as to return to its initial position before it is mounted on the mandrels 22.



  The side sides 104 and 104 'and the butt sides 105, 105' are flattened so as to bring the bead welds 89 along the side edges of the body. The part 102 intended to form the bottom is folded around the lower edge 106 of a lateral side 104 'against the opposite side 104 resulting in triangular sections of the lower end walls which fold in the plane. from the bottom 102 along the fold lines 107., 107 ', and 108, 108' which extend from the end welds 103 and 103 'to the ends of the marginal plies.



   Of course, the invention is in no way limited to the details of the foregoing construction, as many changes and modifications can in fact be made without going beyond its scope.

Claims

CLAIMS.

1.- Process for making a bag starting from a sheet plastic tube, characterized in that a transverse end weld is formed in the lower end of the tube which at this time is flattened, the opening is opened. tube flattened and welded at one end and the part of the tube adjacent to the transverse weld is flattened in a plane which extends transversely of the longitudinal axis of the tube so that triangular sections of the bottom of the bag located at the ends opposites of the transverse end weld extend laterally with respect to the adjacent portions of the tube forming the sides of the bag,

marginal welds are formed which extend perpendicular to the lower transverse weld and which form the opposite side edges of the bottom of the erected bag and parts of the triangular sections which extend outside the last mentioned welds are removed location.

2.- A process for making a bag, characterized in that a transverse marginal weld is formed in the end of a tube intended to form the bag which at this time is flattened, the tube is opened on a form or a mandrel and the part of the tube adjacent to the transverse weld is flattened in a transverse plane so as to form a. bottom for the bag having triangular sections at opposite ends of the transverse weld which extend relative to the adjacent sides of the tube body, marginal welds are formed perpendicular to the first weld which forms the edges opposites from the bottom of the erected bag and the triangular sections which extend outside the last mentioned welds are removed.

3.- A method of making a bag from a plastic sheet material, characterized in that a transverse marginal weld is formed in the end of a tube of thin-walled plastic material which to this moment is flattened, the flattened tube is squared onto a rectangular form or mandrel and the part of the tube adjacent to the cross-weld is flattened into a plane, <Desc / Clms Page number 13> which extends transversely to the longitudinal axis of the tube so as to form a square bottom having triangular sections located at opposite ends of the transverse weld which extend laterally with respect to the adjacent sides of the body of the tube,

forming marginal welds which extend in the triangular sections and perpendicular to the transverse weld to form opposite side edges of the bottom of the erected bag and cutting the triangular sections which extend outside the welds marginals mentioned last.

4.- Method. To make a bag starting from a film of plastic material, characterized in that a sheet of film is transformed into a flattened tube, a blank bag is cut, a marginal weld is formed. transverse in one end of the bag blank, the flattened blank and welded at one end are opened and the portion of the blank adjacent to the transverse weld is folded in a transverse plane so as to form a flat bottom having triangular sections located at opposite ends of the transverse weld which extend laterally with respect to adjacent angles of the body of the blank, flat welds are formed perpendicular to the transverse weld,

these welds intersecting the transverse weld to form the opposite side edges of the bottom of the bag erected in a predetermined manner and the triangular sections which extend outside of the last mentioned marginal welds are cut.

5.- A method of making a bag from a sheet of relatively thin flexible plastic film, characterized in that the sheet is transformed into a tube, the overlapping parts of the tube are welded to form a tube. longitudinal joint, the tube is flattened, the tube is cut into bag blanks, a transverse weld is formed in the end of a blank which at this time is flattened, the tubular blank is opened on a form or an expandable rectangular mandrel, the part of the blank adjacent to the transverse weld is bent in a transverse plane of <Desc / Clms Page number 14> so as to form a bottom for the bag comprising tria sections:

- double thickness gulars at the opposite ends of the transverse narginal weld, two planar marginal welds are formed, perpendicular to the transverse weld which force the opposite side edges of the bottom of the upright bag and remove the parts of the double thickness triangular sections which . extend outside the last mentioned welds.

6.- Method for making a bag starting from a tubular blank in plastic sheet material and one end of which is closed, characterized in that the flattened tubular blank is opened and the part of the adjacent blank is flattened. at the closed end in a plane which extends transversely to the longitudinal axis of the tubular blank so that the triangular sections of the closed end of the blank which forms the bottom of the bag extend laterally of the adjacent portions forming the sides of the bag, parallel transverse marginal welds are formed which extend across triangular sections and which form the opposite side edges of the bottom of the erected bag and the portions are lifted. triangular sections,

which extend outside the transverse welds.

7.- A method for making a bag starting from a tubular blank of plastic sheet material, one end of which is closed, characterized in that a continuous web of sheet material is folded on itself, transversely welded and sectioning the folded web at longitudinal intervals to form a plurality of tubes each having a closed end, each flattened tube is opened and the portion of the tube adjacent to the closed extract is flattened in a transverse plane a.

the longitudinal axis of the open tube so that triangular sections of the closed end of the tube forming the bottom of the bag extend laterally relative to the portions of the tube forming the sides of the bag, parallel transverse welds are formed which extend across triangular sections and which form the opposite side edges of the; <Desc / Clms Page number 15> bottom of the bag erected and parts of the triangular sections which extend outside the cross welds are removed.

8. - A method for making a bag according to claim 7, characterized in that the transverse welds are formed by means of welding members which also cut the projecting parts of the triangular sections.

9. - Bag made from a film of heat-soluble plastic material, characterized in that it comprises a body which, in the open state, has the shape of a tube of substantially rectangular section, comprising two pairs of opposite sides as well as a longitudinal heat-welded joint in one of its sides, and a bottom at one end of the body which comprises a lower heat-welded joint which extends transversely to the longitudinal weld and the length of which corresponds to the transverse dimension of a pair of opposing sides, and heat welded joints parallel to the ends. opposites of the lower seal which are perpendicular to the lower seal and which delimit the lower edges of the other pair of sides.

10.- Bag made of flexible plastic film, characterized in that it comprises a tubular body and a bottom, the body having a rectangular section and the bottom a rectangular shape when the bag is open, the body having a welded joint longitudinal heat seal that extends into the bottom and bottom having a heat welded center seal that extends across the end of the longitudinal seal and that is parallel to two opposite sides of the body, and heat welded marginal seals parallel to the opposite ends of the middle seal which determine the lower edges of the other pair of opposite sides.

11.- Bag made of plastic sheet material, characterized in that it comprises, when empty and flattened, two 'walls forming the body arranged face to face and joined by parallel lateral marginal folds which extend from the 'mouth of the body at a point near its lower end, a longitudinal heat-welded joint extending along one of the side folds <Desc / Clms Page number 16> and a substantially rectangular one-piece bottom with the walls forming the body and folded flat against their lower parts, the bottom having a heat-welded middle seam which extends one way down this bottom and marginal seams d. 'hot-welded end that extend in the other direction,

the lower middle seal being generally parallel to the side plies and the marginal end seals being parallel and placed at the ends of the middle seal, the ends of each middle seal being connected to a side ply by pleats formed in the walls of the body which converge to a meeting point at the lower end of a side fold.

12.- Bag made of plastic sheet characterized in that it comprises, when empty and flattened, two walls? forming the body of the bag arranged face to face and joined in one piece along their parallel side edges by folds which run from the mouth of the body to a point near its inner end, a longitudinal heat-welded joint extending along one of the side folds and a substantially rectangular bottom having opposing edges of one piece with folded triangular bottom sections of the walls forming the body, the bottom.

comprising a heat-welded middle joint which runs transversely in a direction substantially parallel to the side folds and substantially parallel heat-welded end joints which intersect the ends of the lower middle joint, the ex - - end connecting the bottom to the lower edges of the walls forming the body which extend between the lower triangular folded sections of these walls, so that when the bag is erected the side folds of the walls forming the body unfold and the walls open to form two pairs of opposing walls that extend. upwards from the edges of the bottom, each wall striping a width corresponding to the dimension of the lower edge from which it extends.

13.- Bag made from a film of relatively thin flexible plastic material which is initially transformed into a tube with one end closed, characterized in that it comprises a tubular body and a square bottom at the closed end of the body, this square bottom comprising joints hot-welded parallel. those that extend along the bottom edge of two opposite sides.

14.- Bag made from a section of heat-sealed, flexible, relatively thin plastic film which. is initially made into a flattened tube having heat welded bead edges, characterized in that when opened it has a rectangular bottom and a body of rectangular section and heat welded joints which extend into them. lower end * of the parallel sides so as to form two sides of the rectangular bottom.

15.- Bag made of plastic sheet material, characterized in that it comprises, when empty and flattened, two walls forming the body of the bag arranged face to face and joined by parallel lateral marginal folds which go from the side. 'mouth said body at a point near its lower end and which has a longitudinal heat-welded joint in the form of a cardboard, and a substantially rectangular bottom in one piece with the walls forming the body and folded flat against their undersides, the bottom having parallel heat-welded end joints spaced apart in the form of a bead and disposed transversely of a lower edge of one of the folded walls forming the body,

the ends of each end joint 'being connected to a side fold by the folds formed in the walls which converge to a meeting point located at the lower end of a side fold.

16.- Bag characterized in that it comprises a tube having a closed end so as to form a bottom, the bottom ettnt rectangular and having a median seal which extends in the sens of one of its dimensions, and transverse joints which are perpendicular to the middle joint at opposite ends of the latter <Desc / Clms Page number 18> these transverse joints delimiting the lateral edges of the bottom of the bag.

17.- Bag made of a relatively thin flexible plastic film which is initially made into an elongated tube, characterized in that it comprises a tubular body and a square bottom enclosing one end of the tube -, the square bottom comprising H-shaped heat welded seams, two opposing side edges of the bag being forced by flat welded seams which extend outside the walls of the bag.

18.- Bag made from a section of heat-welded, flexible, relatively thin plastic web which is Initially transformed into a tube, the overlapping edges of which are connected by a longitudinal flat heat-welded joint, characterized as that it comprises a rectangular bottom having a heat welded transverse flat gasket which extends across the end of the longitudinal seam and two parallel flat hot welded seams which extend across opposite ends of the transverse joint - salt so as to delimit two edges of the bottom of the bag.

19.- Apparatus for making. bags starting from a heat-sealable plastic film, characterized in that it comprises a device for folding a continuous web of film into a tube, a device for securing and cross-sealing the tube to longitudinal intervals to form several bag blanks each comprising a closed end, several expandable mandrels mounted at a distance from each other on a rotating support, a device for bringing the bag blanks to successive mandrels, a device for sliding each blank on a mandrel which at this moment is contracted,

a device for expanding each successive mandrel to squar the bag blank with the closed end of the blank which bends into a flat plane at the free end of the mandrel and which has end sections in substance triangular which protrude from each side at the end of the mandrel, a hot welding device associated with the turret or rotary support for transversely welding <Desc / Clms Page number 19> the triangular end sections along the end edges of the mandrel, and a trimming device associated with the turret for severing the triangular end sections so as to eliminate the parts which extend outwardly at the top. -delf.

marginal welds- 20.- Apparatus for making bags encased with a plastic film, characterized in that it comprises a device for folding a continuous web of film into a tube, a device for welding and transversely cutting the tube. at intervals to form a plurality of bag blanks each having parallel side welds and a closed end, an expandable mandrel mounted on a support device for bringing the blanks to the mandrel and sliding them onto the mandrel which at this time is contracted,

a device for expanding the mandrel to squar each blank so that its closed end bends flat against the free end of the mandrel and has substantially triangular end sections protruding from. each side at the end of the mandrel, and a device for welding and severing the triangular end sections along the edges of the mandrel.

21 - Apparatus for making bags starting from a plastic film, characterized in that it comprises a device for transforming a continuous web of film into a tube, a device for forming a longitudinal seal in the tube, a device for welding and transversely cutting the tube at intervals to form several bag blanks, an expandable mandrel mounted on a support, a device for.

bring the bag blanks to the mandrel and to slide them over the mandrel which at this moment is contracted, a device for expanding the mandrel in order to squar each bag blank so that its welded end bends flat against the free end of the mandrel and has substantially triangular end sections which protrude from either side of the end of the mandrel, a device <Desc / Clms Page number 20> to cross-weld triangular end sections. along the edges of the mandrel and a device for trimming the parts of the triangular end sections - which extend outwardly beyond the marginal welds * 22.

- Apparatus for making bags from a heat sealable plastic film, characterized in that it comprises a device for converting a continuous sheet of film into a tube, a device for heat sealing the overlapping edges of the web to form a longitudinal joint, a device for sectioning and transverse welding the tube at longitudinal intervals to form several blanks of the bag, several expandable mandrels mounted at a distance from each other on a rotating support, a device for bringing the blanks to successive mandrels, a device for sliding each blank on a mandrel which at this moment is contracted,

a device for expanding each successive mandrel to squar the blank so that its welded end bends in a flat plane at the free end of the mandrel and has its substantially triangular end sections which protrude on either side at the end of the mandrel, a hot welding device associated with the rotating support or turret for transversely welding the triangular end sections along the end edges of the mandrel and a trimming device associated with the turret for. cut the triangular end sections to remove those portions of the sections which extend outward beyond the marginal welds.

23.- Apparatus for making bags from a plastic film, characterized in that it comprises a device for converting a continuous web of the film into a tube, a device for welding side edges film to form a longitudinal seam, a device for transversely welding the tube at longitudinally spaced points so as to form several bag blanks, a device <Desc / Clms Page number 21> to separate each blank from the adjacent blanks, several flat contractile mandrels mounted peripherally at a distance from each other on a support turret,

a device for opening the front ends of successive bag blanks and for sliding them onto the mandrels which at this moment are contracted, a device for expanding the mandrels in order to square the bag blanks in such a way that: welded end forming the bottom of each blank folds flat against the free end of the expanded mandrel and has substantially triangular lower end sections which protrude from either side at the end of the mandrel, a device for Thread the triangular end sections transversely along the edges of the mandrel and a device for cutting the triangular end sections outside the weld lines.

24.- Apparatus for making a bag from a tube of plastic sheet material, one end of which is closed, characterized in that it comprises a mechanism for squaring the flattened blank and for flattening the part of it. the blank adjacent to its closed end in a plane which extends transversely to the longitudinal axis of the blank, this mechanism comprises a rotating turret comprising a series of radial mandrels spaced around its periphery, each mandrel comprising a plate fixed on the turret and a cooperating plate mounted on a slide,

a track for the slider and a device controlled by a cam for moving the slider back and forth on the track in order to bring it closer to the fixed plate and to move it away from it in a manner to expand and contract the mandrel: 25.- Apparatus for making a bag starting from a sheet plastic tube with one end closed, characterized in that it comprises a turret comprising a series of expandable mandrels spaced around its periphery to square the flattened bag blank and to bring the part <Desc / Clms Page number 22> of the blank adjacent to its closed end to bend in a plane which extends transversely to the longitudinal axis of the tubular blank,

each mandrel comprising a rectangular plate fixed to the turret and a cooperating rectangular plate mounted on a slider, a running track on the mandrel to support the slider in order to allow it to move in both directions, a lever actuated by a mounted cam on the turret and in engagement with the slider, a fixed cam to actuate the lever and a device associated with the turret to heat weld and cut the bent parts of the blank at the free ends of the mandrels while the mandrels are expanded by separating the rectangular plates.