WO1994026510A1 - Balancing system for a bending press - Google Patents

Balancing system for a bending press Download PDF

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Publication number
WO1994026510A1
WO1994026510A1 PCT/FR1994/000328 FR9400328W WO9426510A1 WO 1994026510 A1 WO1994026510 A1 WO 1994026510A1 FR 9400328 W FR9400328 W FR 9400328W WO 9426510 A1 WO9426510 A1 WO 9426510A1
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WO
WIPO (PCT)
Prior art keywords
cylinder
pressure
lateral
press brake
cylinders
Prior art date
Application number
PCT/FR1994/000328
Other languages
French (fr)
Inventor
Jean Treillet
Original Assignee
Jean Treillet
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jean Treillet filed Critical Jean Treillet
Publication of WO1994026510A1 publication Critical patent/WO1994026510A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/007—Means for maintaining the press table, the press platen or the press ram against tilting or deflection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/24—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/24—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam
    • B30B15/245—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam using auxiliary cylinder and piston means as actuating members

Definitions

  • the present invention relates to hydraulic press brakes, the movable deck of which is actuated by at least three jacks. Most often, on this type of machine, it is the lower deck which is mobile and actuated by a single-acting hydraulic circuit in which the opening is made by gravity and free flow of oil from the jacks to the tank.
  • the number of cylinders on these machines can be as little as 1, but there are many models available.
  • This central cylinder is double, that is to say that it has two independent sections, namely a first section, for example central e, for rapid approach, receiving all the pump flow during this phase; a second annular section forming, with the first, a double section supplied with pressure during the folding phase and giving a central thrust capable of causing a deformation of the movable deck parallel to that of the fixed deck;
  • This guide although very resistant, does not allow to maintain a correct parallelism between the two decks due to the uncontrolled elastic deformations of the material.
  • the present invention is based on a different principle since it uses two distribution systems as in the first aforementioned solution, while preserving the advantage of parallel deformation due to the presence of a central jack; It is simple and does not require you to enter the digital folding data. It is characterized in that:
  • each lateral cylinder is associated with a central half-cylinder to constitute a unit supplied by its own proportional distributor and managed by its own electronic servo loop called axis card.
  • the lateral jack and the central half jack of a set can be separated so that only one of the two is started.
  • each proportional distributor and the set of cylinders with which it is associated there is a hydraulic distributor with three positions allowing to imitate it, either only a central half-cylinder, or a lateral cylinder, or both at the same pressure .
  • the signal controlling the two distributors is provided by the detection of a parallelism fault, -the invention is extended to several lateral jacks distributed on each side of the center of the press; each cylinder being provided with an open / closed valve and the
  • FIG. 1 represents a press brake equipped with two lateral jacks and a central jack with double section.
  • FIG. 2 represents a first example of an electro-hydraulic diagram in accordance with the invention.
  • FIG. 3 represents a second example of an electro-hydraulic diagram in accordance with the invention.
  • FIG. 4 represents a third example of an electro-hydraulic diagram in accordance with the invention.
  • the press brake shown comprises a frame with its two uprights (1a) and (1b) supporting the fixed upper deck (2) provided with the elongated punch (3) and the movable lower deck (4) provided with the matrix (5). Both contribute to bending the sheet (6) eccentric with respect to the median axis of the press under the effect of a thrust given by 3 jacks (7), (8), (9).
  • the jack (8) is double, that is to say that it has a central section (10) and an annular section (11).
  • To the right of the lateral jacks (7) and (9) are placed two devices for measuring the travel (12) and (13), most often in the form of digital incremental rules connected to two electronic axis cards controlled in parallel. ism.
  • FIG. 2 represents a first embodiment of the electro-hydraulic diagram; the jack (7) and the section (11) of the jack (8) are connected directly to the outlet orifice (16) of the proportional distributor (17). Likewise, the jack (9) and the section (10) are connected to the outlet orifice (18) of the proportional distributor (19).
  • proportional distributors are generally supplemented by a pressure balance, not shown in the diagrams, which makes it possible to deliver an oil flow proportional to the tension applied to the coils whatever the pressure necessary to bend and, conversely, to adapt the distr ibué flow, for a given pressure, to the speed programmed on the axis map.
  • a valve (20) On the conduit connecting the jack (9) to the orifice (18) is a valve (20) allowing to isolate or not this jack.
  • the coils (17a) (17b) (19a) (19b) are supplied with proportional voltage by the amplifiers (21) and (22) which receive their instructions from the axis cards (23) and (24) connected to the incremental rules ( 12) and (13); a comparator and calculator (25) ensures the synchronization of the axis cards (23) and (24) by integrating possible stroke corrections on the lateral jacks to take account of the difference in deformation of the uprights (la) (1b) and maintain the overall parallelism of the two
  • the distributor (26) Upstream of the proportional distributors, the distributor (26) has the task of putting the pump (27) driven by the motor (28) in communication either with the circuit, or with the pilots for opening the non-return valves (29). (30) which, when open, cause the apron to descend after the folding operation.
  • the action on the control member excites the coil (31) of the valve (26) and closes the valve (20). It energizes the coil (19a) of the proportional distributor (19) as much as possible so that the bulkhead rises approach at high speed since all the pump flow passes into the chamber (10) of the jack (8).
  • the other cylinders are filled by suction of oil through the non-return valves (29) and (30).
  • the distributor (19) closes, the valve (20) opens and the work cycle begins; the two proportional distributors (17) and (19) open according to the voltages applied to the coils by the amplifiers (21) and (22), which result from the defined program and from the information provided by rules (12) and (13) ; during this phase, the distribution of pressures in the two sets of cylinders (7) (11) and (9) (10) depends on the position of the more or less eccentric sheet.
  • the double central cylinder always performs its bending role on the movable deck.
  • the maximum eccentricity corresponds to zero pressure in one of the sets of jacks therefore at the position of the center of gravity of the forces applied by the other set, that is to say the barycenter of the forces represented by their sections.
  • the system therefore behaves as if, at this point, there was a virtual cylinder.
  • the race stops at the point fixed by the computer (25) when the two incremental rules (12) (13) arrive at the programmed level.
  • the diagram of this figure 3 has the same base as that of figure 2.
  • the valve (20) is replaced by the distributors (33) and (34) and the jacks (7) and (9) are equipped pressure sensors (14) and (15).
  • the rapid approach stroke is obtained in the same way as in FIG. 2, this time by exciting the coil (37) of the distributor (34); then, at the change of speed, the distributor (34) returns to rest and the two proportional distributors (17) and (19) open according to the voltage applied to the coils as before. If the ratio between the pressures detected by the sensors (15) and (14) or U2 / U1 is greater than a predetermined value, by
  • the computer comparator (25) causes the coils (36) and (38) to be excited so that only the cylinder (9) having the highest pressure is driven by The lower stopper (19) and the lower half (11) with the lowest pressure are supplied by the distributor (17). the other cylinders are then filled by suction through the non-return valves (29) and (40). It is obvious that the system is symmetrical and that for an eccentric sheet on the left, the coils (35) and (37) will be excited when the ratio of the voltages U2 / U1 becomes less than the inverse value of the aforementioned limit.
  • Figure 4 shows the extension of the invention to press brakes whose cylinders are more widely distributed along the movable deck therefore having several lateral cylinders on each side of the axis, or two in the figure.

Abstract

Balancing system for a bending press actuated by at least three actuators (7, 8, 9), the central actuator including an approach section (10) and a complementary section (11). The side actuators are each associated with one of the sections of the central actuator, thus forming two self-contained assemblies (7, 11) and (9, 10); each assembly is controlled by its control loop and the two loops are controlled in parallel. For highly eccentric bending, two distributers (33, 34) suppress the action of the side-actuator with the lowest pressure and that of the central actuator section with the highest pressure. Only one actuator remains operational for each loop, which allows bending to be achieved at the side actuator.

Description

SYSTEME D'EQUILIBRAGE POUR PRESSE-PLIEUSE  BALANCING SYSTEM FOR PRESS BRAKE
La présente invention est relative aux presses-plieuses hydrauliques dont le tablier mobile est actionné par au moins trois vérins. Le plus souvent, sur ce type de machine, c'est le tablier inférieur qui est mobile et actionné par un circuit hydraulique à simple effet dans lequel l'ouverture se fait par gravité et écoulement libre de l'huile des vérins vers la bâche. The present invention relates to hydraulic press brakes, the movable deck of which is actuated by at least three jacks. Most often, on this type of machine, it is the lower deck which is mobile and actuated by a single-acting hydraulic circuit in which the opening is made by gravity and free flow of oil from the jacks to the tank.
Le nombre des vérins de ces machines peut être que 1 conque, mais il existe de nombreux modèles ne  The number of cylinders on these machines can be as little as 1, but there are many models available.
comportant que trois vérins dont un au voisinage de chaque extrémité et un vérin au centre. Ce vérin central est double, c'est à dire qu'il comporte deux sections indépendantes, à savoirrune première section, par exemple central e, pour l'approche rapide, recevant tout le débit de la pompe durant cette phase;une deuxième section annulaire formant, avec la première, une section double alimentée en pression pendant la phase pliage et donnant une poussée centrale apte à provoquer une déformation du tablier mobile parallèle à celle du tablier fixe;cette comprising only three cylinders, one in the vicinity of each end and a cylinder in the center. This central cylinder is double, that is to say that it has two independent sections, namely a first section, for example central e, for rapid approach, receiving all the pump flow during this phase; a second annular section forming, with the first, a double section supplied with pressure during the folding phase and giving a central thrust capable of causing a deformation of the movable deck parallel to that of the fixed deck;
caractéristique est essentielle pour obtenir une bonne régularité de l'angle de pliage. characteristic is essential to obtain good regularity of the bending angle.
Cette conception a été choisie à titre d'exemple non limitatif et il est évident que le vérin central double peut être remplacé par deux vérins juxtaposés ou  This design was chosen by way of nonlimiting example and it is obvious that the double central jack can be replaced by two juxtaposed jacks or
superposés sans que cela change la nature de l'invention. superimposed without changing the nature of the invention.
Dans ces machines, tous les vérins sont alimentés habituellement par un flux d'huile commun donc à une pression i dentique. Lorsque la tôle à plier, moins longue que la presse, est excentrée, il se produit un couple de  In these machines, all the jacks are usually supplied by a common oil flow, therefore at a dental pressure. When the sheet metal to be folded, which is shorter than the press, is offset, a couple of
basculement qui ne peut être compensé que par un guidage mécanique. Ce guidage, bien que très résistant, ne permet pas de conserver un parallélisme correct entre les deux tabliers en raison des déformations élastiques non maîtrisées de la matière. tilting which can only be compensated by mechanical guidance. This guide, although very resistant, does not allow to maintain a correct parallelism between the two decks due to the uncontrolled elastic deformations of the material.
Pour pallier ce défaut, deux solutions ont été prévues: -Supprimer le vérin central et commander les vérins latéraux séparément par leur propre système de distribution asservi au parallèlisme; cette solution perd l'avantage de la déformée parallèle des deux tabliers si aucun dispositif spécial additionnel n'est mis en oeuvre. -Placer, comme prévu dans le brevet français 89 16778, entre les trois vérins et l'alimentation centrale, des organes de modification de distribution, pression et débit, agissant de façon différente sur ces vérins et asservis à un détecteur de parallelisme. Cette solution est relativement complexe et nécessite l'entrée de données extérieures, sous forme de paramètres, tels que la force, la longueur pliée,la position de la tôle, etc... To remedy this defect, two solutions have been provided: -Delete the central jack and order the side jacks separately by their own distribution system controlled by parallelism; this solution loses the advantage of the parallel deformation of the two decks if no additional special device is used. -Place, as provided in French patent 89 16778, between the three jacks and the central supply, distribution, pressure and flow modification members, acting differently on these jacks and controlled by a parallelism detector. This solution is relatively complex and requires the input of external data, in the form of parameters, such as the force, the folded length, the position of the sheet, etc.
La présente invention relève d'un principe différent puisqu'elle fait appel à deux systèmes de distribution comme dans la première solution précitée, tout en préservant l'avantage de la déformée parallèle due à la présence d'un vérin central; Elle est simple et ne nécessite pas de rentrer les données numériques du pliage. Elle est caractérisée en ce que:  The present invention is based on a different principle since it uses two distribution systems as in the first aforementioned solution, while preserving the advantage of parallel deformation due to the presence of a central jack; It is simple and does not require you to enter the digital folding data. It is characterized in that:
-Chaque vérin latéral est associé à un demi-vérin central pour constituer un ensemble alimenté par son propre distributeur proportionnel et géré par sa propre boucle d'asservissement électronique appelée carte d'axe.  -Each lateral cylinder is associated with a central half-cylinder to constitute a unit supplied by its own proportional distributor and managed by its own electronic servo loop called axis card.
-En phase d' approche, l'un des demi-vérins centraux est seul alimenté grâce à la pleine ouverture de son distributeur proportionnel ainsi qu'à la fermeture de la vanne située sur le circuit alimentant le vérin latéral qui lui est associé. -In approach phase, only one of the central half-cylinders is supplied thanks to the full opening of its proportional distributor as well as the closing of the valve located on the circuit supplying the lateral cylinder associated with it.
-Le vérin latéral et le demi-vérin central d'un ensemble peuvent être dissociés afin que l'un des deux seulement soit al intenté. -The lateral jack and the central half jack of a set can be separated so that only one of the two is started.
-Entre chaque distributeur proportionnel et l'ensemble de vérins auquel il est associé, se trouve un distributeur hydraulique à trois positions permettant d' al imenter, soit seulement un demi-vérin central, soit un vérin latéral, soit les deux à la même pression.  -Between each proportional distributor and the set of cylinders with which it is associated, there is a hydraulic distributor with three positions allowing to imitate it, either only a central half-cylinder, or a lateral cylinder, or both at the same pressure .
-II existe un signal agissant sur les deux distributeurs à trois positions de manière à éliminer l'alimentation du vérin latéral ayant la pression la plus basse ainsi que celle du vérin central ayant la pression la plus élevée. -Le signal résulte de la comparaison des pressions dans les deux vérins latéraux.  -There is a signal acting on the two distributors with three positions so as to eliminate the supply of the lateral jack having the lowest pressure as well as that of the central jack having the highest pressure. -The signal results from the comparison of the pressures in the two lateral cylinders.
-Le signal est activé pour commander deux bobines -The signal is activated to control two coils
homologues des distributeurs lorsque le rapport des pressions droite-gauche est supérieur à une valeur prédéterminée, ou pour commander les deux autres bobines lorsque le rapport des pressions droite-gauche est inférieur à l'inverse de cette même valeur. counterparts of distributors when the report of right-left pressures is greater than a predetermined value, or to control the other two coils when the ratio of right-left pressures is less than the inverse of this same value.
-Le signal commandant les deux distributeurs est fourni par la détection d'un défaut de parallélisme, -l'invention est étendue à plusieurs vérins latéraux répartis de chaque côté du centre de la presse; chaque vérin étant muni d'une valve ouverte/fermée et la -The signal controlling the two distributors is provided by the detection of a parallelism fault, -the invention is extended to several lateral jacks distributed on each side of the center of the press; each cylinder being provided with an open / closed valve and the
répartition des fermetures de valves se faisant par itération en fonction de la détection d'un défaut de parai lèl isme. distribution of valve closures by iteration as a function of the detection of a defect in the appearance of the valve.
D'autres caractéristiques et avantages de l'invention apparaîtront à travers la description qui suit de deux exemples de réalisation illustrés par les dessins annexés parmi lesquels:  Other characteristics and advantages of the invention will become apparent from the following description of two exemplary embodiments illustrated by the appended drawings among which:
-La figure 1 représente une presse-plieuse équipée de deux vérins latéraux et d'un vérin central à double section.. -La figure 2 représente un premier exemple de schéma électro-hydraulique conforme à l'invention.  FIG. 1 represents a press brake equipped with two lateral jacks and a central jack with double section. FIG. 2 represents a first example of an electro-hydraulic diagram in accordance with the invention.
-La figure 3 représente un deuxième exemple de schéma électro-hydraulique conforme à l'invention.  FIG. 3 represents a second example of an electro-hydraulic diagram in accordance with the invention.
-La figure 4 représente un troisième exemple de schéma électro-hydraulique conforme à l'invention.  FIG. 4 represents a third example of an electro-hydraulic diagram in accordance with the invention.
Sur 1a figure 1,1a presse-plieuse représentée comprend un bâti avec ses deux montants (1a) et (1b) supportant 1e tablier supérieur fixe (2) muni du poinçon allongé (3) et le tablier inférieur mobile (4) muni de la matrice (5). Tous deux contribuent à plier 1a tôle (6) excentrée par rapport à l'axe médian de 1a presse sous l'effet d'une poussée donnée par 3 vérins (7), (8), (9).  In FIG. 1.1a, the press brake shown comprises a frame with its two uprights (1a) and (1b) supporting the fixed upper deck (2) provided with the elongated punch (3) and the movable lower deck (4) provided with the matrix (5). Both contribute to bending the sheet (6) eccentric with respect to the median axis of the press under the effect of a thrust given by 3 jacks (7), (8), (9).
Le vérin (8) est double, c'est à dire qu'il comporte une section (10) centrale et une section (11) annulaire. Au droit des vérins latéraux (7) et (9) sont placés deux appareils de mesure de la course (12) et (13), le plus souvent sous forme de règles incrémentales digitales raccordées à deux cartes d'axe électroniques asservies en parai lèl isme.  The jack (8) is double, that is to say that it has a central section (10) and an annular section (11). To the right of the lateral jacks (7) and (9) are placed two devices for measuring the travel (12) and (13), most often in the form of digital incremental rules connected to two electronic axis cards controlled in parallel. ism.
Selon le mode de fonctionnement, des capteurs de  Depending on the operating mode,
pression (14) et (15) raccordés respectivement aux vérins (7) et (9) délivrent des tensions électriques U1,U2 proportionnelles aux pressions existant respectivement dans ces vérins. pressure (14) and (15) respectively connected to the cylinders (7) and (9) deliver electrical voltages U1, U2 proportional to the pressures existing respectively in these jacks.
La figure 2 représente un premier mode de réalisation du schéma électro-hydraulique; le vérin(7) et la section (11) du vérin (8) sont reliés directement à l'orifice (16) de sortie du distributeur proportionnel (17). De même, le vérin (9) et la section (10) sont reliés à l'orifice (18) de sortie du distributeur proportionnel (19).  FIG. 2 represents a first embodiment of the electro-hydraulic diagram; the jack (7) and the section (11) of the jack (8) are connected directly to the outlet orifice (16) of the proportional distributor (17). Likewise, the jack (9) and the section (10) are connected to the outlet orifice (18) of the proportional distributor (19).
Rappelons que les distributeurs proportionnels sont généralement complétés par une balance de pression, non représentée sur les schémas, qui permet de délivrer un débit d'huile proportionnel à la tension appliquée aux bobines quelle que soit la pression nécessaire pour plier et, réciproquement, d' adapter le débit distr ibué, pour une pression donnée, au régime programmé à la carte d'axe.  Recall that the proportional distributors are generally supplemented by a pressure balance, not shown in the diagrams, which makes it possible to deliver an oil flow proportional to the tension applied to the coils whatever the pressure necessary to bend and, conversely, to adapt the distr ibué flow, for a given pressure, to the speed programmed on the axis map.
Sur le conduit reliant le vérin (9) à l'orifice (18) se trouve une valve (20) permettant d'isoler ou non ce vérin. Les bobines (17a) (17b) (19a) (19b) sont alimentées en tension proportionnelle par les amplificateurs (21) et (22) qui reçoivent leur consigne des cartes d'axe (23) et (24) reliées aux règles incrémentales (12) et (13); un comparateur et calculateur (25) assure la synchronisation des cartes d'axe (23) et (24) en intégrant d'éventuelles corrections de course sur les vérins latéraux pour tenir compte de la différence de déformation des montants (la) (1b) et maintenir le parallélisme global des deux  On the conduit connecting the jack (9) to the orifice (18) is a valve (20) allowing to isolate or not this jack. The coils (17a) (17b) (19a) (19b) are supplied with proportional voltage by the amplifiers (21) and (22) which receive their instructions from the axis cards (23) and (24) connected to the incremental rules ( 12) and (13); a comparator and calculator (25) ensures the synchronization of the axis cards (23) and (24) by integrating possible stroke corrections on the lateral jacks to take account of the difference in deformation of the uprights (la) (1b) and maintain the overall parallelism of the two
tabliers (2) et (4)même en travail excentré. aprons (2) and (4) even in offset work.
En amont des distributeurs proportionnels, le distributeur (26) a pour tâche de mettre la pompe (27) entraînée par le moteur (28) en communication soit avec le circuit, soit avec les pilotes d'ouverture des clapets anti-retour (29) (30) qui, lorsqu'ils sont ouverts, provoquent la descente du tablier aprèè l'opération de pliage.  Upstream of the proportional distributors, the distributor (26) has the task of putting the pump (27) driven by the motor (28) in communication either with the circuit, or with the pilots for opening the non-return valves (29). (30) which, when open, cause the apron to descend after the folding operation.
Le fonctionnement du cycle est le suivant:  The cycle works as follows:
L'action sur l'organe de commande, non représenté, excite la bobine (31) de la valve (26)et ferme la valve (20). Elle met sous tension maximum la bobine (19a) du distributeur proportionnel (19) de sorte que 1e tablier monte en approche à grande vitesse puisque tout le débit de la pompe passe dans la chambre (10) du vérin (8). Les autres vérins sont remplis par aspiration d'huile à travers les clapets anti-retour (29) et (30). Arrivé au point de changement de vitesse, détecté par l'une des règles incrémentales (12) (13), le distributeur (19) se ferme, la valve (20) s'ouvre et le cycle de travail commence; les deux distributeurs proportionnels (17) et (19) s'ouvrent suivant les tensions appliquées aux bobines par les amplificateurs (21) et (22), qui résultent du programme défini et des informations fournies par les règles (12) et (13); pendant cette phase, la répartition des pressions dans les deux ensembles de vérins (7) (11) et (9) (10) dépend de la position de la tôle plus ou moins excentrée. Le vérin central double assure toujours son rôle de bombage sur le tablier mobile. On remarquera que l'excentration maximum correspond à une pression nulle dans un des ensembles de vérins donc à la position du centre de gravité des forces appliquées par l'autre ensemble c'est à dire le barycentre des forces représentées par leurs sections. Le système se comporte donc comme si, en ce point, il y avait un vérin virtuel. La course s'arrête au point fixé par le calculateur (25) lorsque les deux règles incrémentales (12) (13) arrivent au niveau programmé. Lorsque l'ordre d'ouverture est donné, celle-ci se fait en deux temps: The action on the control member, not shown, excites the coil (31) of the valve (26) and closes the valve (20). It energizes the coil (19a) of the proportional distributor (19) as much as possible so that the bulkhead rises approach at high speed since all the pump flow passes into the chamber (10) of the jack (8). The other cylinders are filled by suction of oil through the non-return valves (29) and (30). Arrived at the speed change point, detected by one of the incremental rules (12) (13), the distributor (19) closes, the valve (20) opens and the work cycle begins; the two proportional distributors (17) and (19) open according to the voltages applied to the coils by the amplifiers (21) and (22), which result from the defined program and from the information provided by rules (12) and (13) ; during this phase, the distribution of pressures in the two sets of cylinders (7) (11) and (9) (10) depends on the position of the more or less eccentric sheet. The double central cylinder always performs its bending role on the movable deck. It will be noted that the maximum eccentricity corresponds to zero pressure in one of the sets of jacks therefore at the position of the center of gravity of the forces applied by the other set, that is to say the barycenter of the forces represented by their sections. The system therefore behaves as if, at this point, there was a virtual cylinder. The race stops at the point fixed by the computer (25) when the two incremental rules (12) (13) arrive at the programmed level. When the opening order is given, it is done in two stages:
Un premier temps pour la décompression de tous les vérins à travers les distributeurs proportionnels (17) et (19) dont les bobines (17b) et (19b) reçoivent une tension modulée;un deuxième temps pour le retour rapide par l'excitation de la bobine (32) qui ouvre les clapets (29) (30) par alimentation de leur pilote respectif.  A first time for the decompression of all the cylinders through the proportional distributors (17) and (19) whose coils (17b) and (19b) receive a modulated voltage; a second time for the rapid return by the excitation of the coil (32) which opens the valves (29) (30) by supplying their respective pilot.
Dans ce premier exemple de réal isation, nous avons vu que l'excentration de la tôle ne pouvait pas dépasser l'axe des vérins virtuels. C'est pourquoi l'invention est complétée par la solution représentée sur la figure 3 qui permet d'excentrer la tôle jusqu'au droit d'un vérin latéral.  In this first example of realization, we have seen that the eccentricity of the sheet cannot exceed the axis of the virtual cylinders. This is why the invention is completed by the solution shown in FIG. 3 which allows the sheet to be offset as far as the right of a lateral jack.
Le schéma de cette figure 3 a la même base que celui de la figure 2. La valve (20) est remplacée par les distributeurs (33) et (34) et les vérins (7) et (9) sont équipés des capteurs de pression (14) et (15). La course d'approche rapide s'obtient de la même manière que sur la figure 2, en excitant, cette fois la bobine (37) du distributeur (34);puis,au changement de vitese,le distributeur (34) revient au repos et les deux distributeurs proportionnels (17) et (19) s'ouvrent suivant la tension appliquée aux bobines comme précédemment. Si le rapport entre les pressions détectées par les capteurs (15) et (14) soit U2/U1 est supérieur à une valeur prédéterminée, par The diagram of this figure 3 has the same base as that of figure 2. The valve (20) is replaced by the distributors (33) and (34) and the jacks (7) and (9) are equipped pressure sensors (14) and (15). The rapid approach stroke is obtained in the same way as in FIG. 2, this time by exciting the coil (37) of the distributor (34); then, at the change of speed, the distributor (34) returns to rest and the two proportional distributors (17) and (19) open according to the voltage applied to the coils as before. If the ratio between the pressures detected by the sensors (15) and (14) or U2 / U1 is greater than a predetermined value, by
exemple, parce que la tôle est excentrée à droite, le comparateur calculateur (25) provoque l'excitation des bobines (36) et (38) de sorte que, seuls le vérin (9) ayant la pression la plus haute es t a l imenté par l e d i s tr i buteur ( 19 ) e t l e dem i -vér i n (11) ayant la pression la plus basse est alimenté par le distributeur (17). les autres vérins sont alors remplis par aspiration à travers les clapets anti-retour (29) et (40). IL est évident que le système est symétrique et que pour une tôle excentrée à gauche, les bobines (35) et (37) seront excitées lorsque le rapport des tensions U2/U1 deviendra inférieur à la valeur inverse de la limite précitée. example, because the sheet is eccentric to the right, the computer comparator (25) causes the coils (36) and (38) to be excited so that only the cylinder (9) having the highest pressure is driven by The lower stopper (19) and the lower half (11) with the lowest pressure are supplied by the distributor (17). the other cylinders are then filled by suction through the non-return valves (29) and (40). It is obvious that the system is symmetrical and that for an eccentric sheet on the left, the coils (35) and (37) will be excited when the ratio of the voltages U2 / U1 becomes less than the inverse value of the aforementioned limit.
On voit donc que, pour une forte excentrâtion, il reste en pression seulement un vérin pour chaque carte d'axe; par conséquent, si la résultante des efforts de pliage se trouve au voisinage de l'axe du vérin (9) par exemple, la pression dans le demi-vérin (11) tend vers zéro et le parallélisme est conservé.  We therefore see that, for a strong offset, there remains only one cylinder in pressure for each axis card; consequently, if the result of the folding forces is in the vicinity of the axis of the jack (9) for example, the pressure in the half-jack (11) tends towards zero and the parallelism is preserved.
Le reste du fonctionnement se comporte comme dans le cas précédent.  The rest of the operation behaves as in the previous case.
Bien entendu, on peut imaginer d'autres systèmes de détection que les capteurs de pression dans les vérins latéraux;on peut, par exemple, détecter directement le défaut de parallèlisme, témoin de l'impossibilité d'équilibrer le couple de basculement par la simple répartition des pressions dans tous les vérins. On peut aussi prendre l'information directement sur la carte d'axe qui n'arrive pas à atteindre la vitesse programmée sur le côté le plus chargé, ou l'inverse.  Of course, one can imagine other detection systems than the pressure sensors in the lateral cylinders; one can, for example, directly detect the lack of parallelism, witnessing the impossibility of balancing the tilting torque by the simple pressure distribution in all cylinders. We can also take the information directly from the axis map which does not reach the programmed speed on the most loaded side, or vice versa.
On remarquera, en outre, que l'action sur les distributeurs (33) et (34) ne provoque pas de décompression brutale puisque les vérins sont simplement isolés sans mise en communication avec la bâche grâce à l'utilisation de distributeurs à transfert fermé. La décompression se fait donc doucement dans le demi-vérin central par le fait que le piston continue sa course, puis, dès que la décompression est terminée, le clapet anti-retour (39), (40) s'ouvre pour laisser entrer l'huile dans le demi-vérin. Quant au vérin latéral, sa pression était, par conception, très faible mais la décompression se fait de la même manière. It will also be noted that the action on the distributors (33) and (34) does not cause decompression brutal since the cylinders are simply isolated without communication with the cover thanks to the use of closed transfer distributors. The decompression is therefore done slowly in the central half-cylinder by the fact that the piston continues its stroke, then, as soon as the decompression is finished, the non-return valve (39), (40) opens to let in. in the half cylinder. As for the lateral cylinder, its pressure was, by design, very low but the decompression is done in the same way.
A ce stade, il faut remarquer que l'augmentation de vitesse qui pourrait résulter de l'élimination brusque d'un des ensembles de vérins est vite corrigée par la réaction de la carte d'axe qui est capable de modifier la tension appliquée aux distributeurs proportionnels dans le temps très court de un à deux dixièmes de seconde, c'est à dire sur environ un millimètre de course; la partie excédentaire du débit étant alors envoyée à la bâche par le canal (60).  At this stage, it should be noted that the increase in speed which could result from the abrupt elimination of one of the sets of cylinders is quickly corrected by the reaction of the axis card which is capable of modifying the voltage applied to the distributors. proportional in very short time from one to two tenths of a second, that is to say over a millimeter of travel; the excess part of the flow then being sent to the cover by the channel (60).
La figure 4 montre l'extension de l'invention à des presses-plieuses dont les vérins sont plus amplement répartis le long du tablier mobile donc possédant plusieurs vérins latéraux de chaque côté de l'axe, soit deux sur la figure.  Figure 4 shows the extension of the invention to press brakes whose cylinders are more widely distributed along the movable deck therefore having several lateral cylinders on each side of the axis, or two in the figure.
Dans ce cas, il devient plus simple de remplacer les distributeurs (33) et (34) par une série de valves à deux positions ouverte/fermée (41) à (46) à raison d'une valve par vérin (51) (52) (11) (10) (55) (56) et de les commander par itération à partir de la détection d'un défaut de parallèlisms.  In this case, it becomes simpler to replace the distributors (33) and (34) with a series of two-position valves open / closed (41) to (46) due to one valve per cylinder (51) (52 ) (11) (10) (55) (56) and to order them by iteration from the detection of a parallelism defect.
Supposons, par exemple que la tôle est pliée à droite si la répartition des pressions entre la série des trois vérins de droite (10) (55) (56)et la série des trois vérins de gauche (51) (52) (11)ne permet pas d'équilibrer le tablier, et que, par conséquent, un défaut de parallélisme est détecté, les valves (41) et (44) se ferment puis, si c'est insuffisant, la valve (42) se ferme à son tour.11 ne reste alors en service, à gauche, que le demi-vérin (11) et, à droite, que les vérins (55) et (56) . Enf in, si la résultante des efforts de pliage est au droit du vérin (56), l'équilibrage ne sera obtenu que par la fermeture de la valve (45) donc de l'isolement du vérin (55). On voit donc l'analogie totale avec le cas de la figure 3, seule la distribution est légèrement différente pour être mieux adaptée à ce cas. Suppose, for example, that the sheet is bent to the right if the distribution of pressures between the series of the three cylinders on the right (10) (55) (56) and the series of the three cylinders on the left (51) (52) (11) does not allow the deck to be balanced, and that, consequently, a parallelism fault is detected, the valves (41) and (44) close then, if it is insufficient, the valve (42) closes at its tour.11 then remains in service, on the left, only the half-cylinder (11) and, on the right, only the cylinders (55) and (56). Finally, if the result of the bending forces is in line with the cylinder (56), balancing will only be obtained by closing the valve (45) and therefore the isolation of the jack (55). We therefore see the total analogy with the case of Figure 3, only the distribution is slightly different to be better suited to this case.
Il n'est pas exclu que cette variante de distribution soit appliquée au cas précédent, les distributeurs (33) et (34) étant remplacés par 4 valves ouvertes/fermées.  It is not excluded that this distribution variant is applied to the previous case, the distributors (33) and (34) being replaced by 4 open / closed valves.
Tous les utilisateurs de presse-plieuse connaissaient l'avantage de qualité fourni par les machines à' trois vérins ou plus mais ils ne pouvaient pas obtenir une qualité comparable en travail excentré. Or, le travail excentré permet, en particulier, de monter plusieurs postes de travail sur la même machine ce qui présente un surcroît de productivité important et est largement pratiqué dans la fabrication des boites de toutes formes qui nécessitent, pour être bien ajustées, une excellente qualité de pliage. La présente invention constitue le moyen le plus simple pour obtenir cette qualité en travail excentré, ce qui permet d'envisager un large développement de ce type de machine.  All users of the press brake were aware of the quality advantage provided by machines with three or more cylinders, but they could not achieve comparable quality in offset work. However, the offset work allows, in particular, to mount several workstations on the same machine which has a significant increase in productivity and is widely practiced in the manufacture of boxes of all shapes which require, to be properly adjusted, excellent folding quality. The present invention is the simplest way to obtain this quality in offset work, which makes it possible to envisage a wide development of this type of machine.

Claims

R E V E N D I C A T I O N S
1. Presse-plieuse hydraulique dont le tablier mobile (4) est actionné par au moins trois vérins (7) (8) (9) c'est à dire un vérin à chaque extrémité de la presse et, au centre, soit un vérin double composé de deux sections 1. Hydraulic press brake, the movable deck (4) of which is actuated by at least three jacks (7) (8) (9), that is to say one jack at each end of the press and, in the center, one jack double composed of two sections
(10) (11) concentriques soit deux vérins côte à côte ou superposés; le débit et la pression dans les vérins étant distribués par un système électro-hydraulique comportant deux asservissements électroniques aptes à gérer la course du tablier mobile et le parallélisme entre les deux tabliers et équipés chacun d'un organe de mesure (12) (13) situé au voisinage d'un vérin latéral, et d'un distributeur hydraulique proportionnel (17) (19); chaque vérin latéral étant éventuellement équipé d'un capteur de pression (14) (15); caractérise en ce que chaque vérin latéral (7) (9) est associé respectivement à un demi-vérin central (11)(10) pour constituer un ensemble alimenté par son propre distributeur proportionnel (17) (19) et géré par sa propre boucle d'asservissement électronique(10) (11) concentric either two cylinders side by side or superimposed; the flow and pressure in the cylinders being distributed by an electro-hydraulic system comprising two electronic servos capable of managing the stroke of the movable deck and the parallelism between the two decks and each equipped with a measuring member (12) (13) located in the vicinity of a lateral jack, and a proportional hydraulic distributor (17) (19); each lateral jack possibly being fitted with a pressure sensor (14) (15); characterized in that each lateral cylinder (7) (9) is associated respectively with a central half-cylinder (11) (10) to constitute an assembly supplied by its own proportional distributor (17) (19) and managed by its own loop electronic servo
2. Presse plieuse selon la revendication 1 caractérisée en ce que, en phase d' approche, l'alimentation de l'un des demi-vérins centraux (10) se fait par la pleine ouverture de son distributeur proportionnel (19) ainsi que par la fermeture de la valve (20) située sur le circuit 2. Press brake according to claim 1 characterized in that, in the approach phase, the supply of one of the central half-cylinders (10) is done by the full opening of its proportional distributor (19) as well as by closing the valve (20) located on the circuit
d'alimentation du vérin laréral (9) qui lui est associé. supplying the side cylinder (9) associated therewith.
3. Presse-plieuse selon la revendication 1 caractérisée en ce que le vérin latéral (7) (9) et le demi-vérin central (11) (10) d'un ensemble peuvent être dissociés de sorte que l'un des deux seulement soit alimenté en pression. 3. Press brake according to claim 1 characterized in that the lateral cylinder (7) (9) and the central half-cylinder (11) (10) of an assembly can be separated so that only one of the two is supplied with pressure.
4. Presse-plieuse selon la revendication 3 caractérisée en ce que, entre chacun des distributeurs proportionnels (17)(19) et l'ensemble des vérins auquel il est associé, se trouve un distributeur hydraulique à trois positions (33) (34) permettant d'alimenter soit seulement un vérin latéral (7) (9) soit seulement un vérin central (11) (10) soit les deux à la même pression. 4. Press brake according to claim 3 characterized in that, between each of the proportional distributors (17) (19) and the set of jacks with which it is associated, there is a hydraulic distributor with three positions (33) (34) allowing to feed either only a lateral cylinder (7) (9) or only a central cylinder (11) (10) or both at the same pressure.
5. Presse-plieuse selon la revendication 4 caractérisée en ce qu'il existe un signal capable d'agir sur les deux distributeurs à trois positions (33) (34) de manière à éliminer l'alimentation du vérin latéral ayant la pression la plus basse ainsi que celle du demi-vérin central ayant la pression la plus haute. 5. Press brake according to claim 4 characterized in that there is a signal capable of acting on the two distributors with three positions (33) (34) so as to eliminate the supply of the lateral jack having the most pressure as well as that of the central half-cylinder having the highest pressure.
6. Presse-plieuse selon la revendication 5 caractérisée en ce que le signal résulte de la comparaison des 6. Press brake according to claim 5 characterized in that the signal results from the comparison of
pressions dans les deux vérins latéraux fournies par les capteurs de pression (14) (15). pressures in the two lateral cylinders supplied by the pressure sensors (14) (15).
7. Presse-plieuse selon la revendication 5 caractérisée en ce que le signal est activé pour commander les bobines homologues (36) (38) des deux distributeurs lorsque le rapport des pressions droite/gauche (15)/(14)est supérieur à une valeur prédéterminée, ou pour commander les bobines homologues (35) (37) lorsque le rapport des pressions droite/gauche (15)/(14) est inférieur à l'inverse de cette même valeur. 7. Press brake according to claim 5 characterized in that the signal is activated to control the homologous coils (36) (38) of the two distributors when the right / left pressure ratio (15) / (14) is greater than one predetermined value, or to control the homologous coils (35) (37) when the right / left pressure ratio (15) / (14) is less than the inverse of this same value.
8. Presse-plieuse selon la revendication 5 caractérisée en ce que le signal commandant les deux distributeurs (33) (34) dans un sens ou dans l'autre est fourni par la détection d'un défaut de parallélisme. 8. Press brake according to claim 5 characterized in that the signal controlling the two distributors (33) (34) in one direction or the other is provided by the detection of a parallelism fault.
9. Presse-plieuse selon la revendication 1 comportant plusieurs vérins latéraux de chaque côté de l'axe de la presse; caractérisée en ce que chacun des vérins est muni d'une valve ouverte/fermée (41)à (46); la répartition des fermetures de valves se faisant par itération en fonction de la détection d'un défaut de parallélisme. 9. Press brake according to claim 1 comprising several lateral cylinders on each side of the axis of the press; characterized in that each of the jacks is provided with an open / closed valve (41) to (46); the distribution of valve closures is done by iteration as a function of the detection of a parallelism fault.
PCT/FR1994/000328 1993-05-10 1994-03-24 Balancing system for a bending press WO1994026510A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9305596A FR2705052B1 (en) 1993-05-10 1993-05-10 BALANCING SYSTEM FOR PRESS BRAKE WITH 3 AND MORE JACKS.
FR93/05596 1993-05-10

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WO1994026510A1 true WO1994026510A1 (en) 1994-11-24

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BE1016706A5 (en) * 2005-07-26 2007-05-08 Haco Nv Press device with enhanced parallel system like.

Citations (6)

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US2343167A (en) * 1941-06-21 1944-02-29 Hydraulic Dev Corp Inc Press leveling means
US3677009A (en) * 1970-11-12 1972-07-18 Kelso Marine Inc Control arrangement for the male die of a hydraulic press brake
JPS56109905A (en) * 1980-01-30 1981-08-31 Uchida Yuatsu Kiki Kogyo Kk Disturbance eliminating method in cylinder synchronizing system
JPS5922109A (en) * 1982-07-29 1984-02-04 Uchida Yuatsu Kiki Kogyo Kk Synchronous controlling method of three cylinders
SU1539401A1 (en) * 1988-01-18 1990-01-30 Рязанский завод тяжелого кузнечно-прессового оборудования Hydraulic system for synchronizing the cylinders ,particularly, of sheet-bending machine
EP0434541A1 (en) * 1989-12-19 1991-06-26 Amada S.A. Hydraulic bending press with movable lower beam

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Publication number Priority date Publication date Assignee Title
US2343167A (en) * 1941-06-21 1944-02-29 Hydraulic Dev Corp Inc Press leveling means
US3677009A (en) * 1970-11-12 1972-07-18 Kelso Marine Inc Control arrangement for the male die of a hydraulic press brake
JPS56109905A (en) * 1980-01-30 1981-08-31 Uchida Yuatsu Kiki Kogyo Kk Disturbance eliminating method in cylinder synchronizing system
JPS5922109A (en) * 1982-07-29 1984-02-04 Uchida Yuatsu Kiki Kogyo Kk Synchronous controlling method of three cylinders
SU1539401A1 (en) * 1988-01-18 1990-01-30 Рязанский завод тяжелого кузнечно-прессового оборудования Hydraulic system for synchronizing the cylinders ,particularly, of sheet-bending machine
EP0434541A1 (en) * 1989-12-19 1991-06-26 Amada S.A. Hydraulic bending press with movable lower beam

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PATENT ABSTRACTS OF JAPAN vol. 5, no. 189 (M - 99) 28 November 1981 (1981-11-28) *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 113 (P - 276) 4 February 1984 (1984-02-04) *

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FR2705052B1 (en) 1995-06-30

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