EP0268894B1 - Drawing device for a press - Google Patents

Drawing device for a press Download PDF

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Publication number
EP0268894B1
EP0268894B1 EP87116280A EP87116280A EP0268894B1 EP 0268894 B1 EP0268894 B1 EP 0268894B1 EP 87116280 A EP87116280 A EP 87116280A EP 87116280 A EP87116280 A EP 87116280A EP 0268894 B1 EP0268894 B1 EP 0268894B1
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EP
European Patent Office
Prior art keywords
pressure
piston
space
spaces
pistons
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EP87116280A
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German (de)
French (fr)
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EP0268894A3 (en
EP0268894A2 (en
Inventor
Siegfried Baur
Rudi Brandstetter
Gerhard Roos
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L Schuler GmbH
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L Schuler GmbH
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Publication of EP0268894A2 publication Critical patent/EP0268894A2/en
Publication of EP0268894A3 publication Critical patent/EP0268894A3/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/10—Devices controlling or operating blank holders independently, or in conjunction with dies
    • B21D24/14—Devices controlling or operating blank holders independently, or in conjunction with dies pneumatically or hydraulically

Definitions

  • the invention relates to a pulling device for a press of the generic type.
  • Such a pulling device is described in DE-A1-35 05 984 & EP-A-0 192 115.
  • the various individual functions of the pulling device are independently adjustable and controllable.
  • the drawing device has pressure cylinders for sheet metal holding during the drawing and pressure cylinders for ejecting the workpieces, as well as a pressure cheek guided in the press table and movable and supported by the pressure cylinders. After the working stroke of the drawing ram, follow-up control devices come into effect for a time-independent ramp-up of ejector and drawing piston rods.
  • the drawing piston rods can be detached from the underside of the pressure cheek.
  • the sheet inserted into the tool is first pressed against the sheet holder by the drawing ring and then moved together with the sheet holder against the holding force exerted by the drawing device.
  • the ram In addition to the holding force to be exerted by the pulling device, the ram must also overcome the inertial forces which come into effect as a result of the acceleration of the movable masses of the sheet metal holder and pulling device at the beginning of the deformation.
  • the drawing device in FIG. 1 has a number of printing cylinders 3 for sheet metal holding and at least one printing cylinder 5 for ejecting the shaped workpiece.
  • the pressure cylinders 3 and 5 are held by a bracket 8, which can be part of the press table, and act on the pressure cheek 1 from below via their piston rods 4 and 31.
  • the piston rods 4 can be detached from the underside of the pressure cheek 1 for ejector operation.
  • Ball sockets are indicated by 30 and 32 respectively.
  • pressure rods 2 Above the pressure beam 1, pressure rods 2 are shown, which engage in the drawing tool on the press table and are placed against the sheet metal holder or an Auserfer element.
  • the piston rods 4 and 31 are extended downward and extend into an additional additional pressure cylinder 6 and 7, respectively.
  • the diameters are those with the piston rods 31, 4 Pistons 22 and 23 carried along are of different sizes if, for example, the same pressure conditions are to prevail in the pressure cylinders 6, 7.
  • a pressure chamber 36 and 9 is provided above each of the pressure pistons 22, 23, the actual effective surface 33 and 34 of each piston 22, 23 and thus the piston rods 31, 4 being moved in the direction of pull 37 when they are pressurized. Stops 25 limit the movement of the piston rods 31, 4 in the upward movement.
  • the pressure chamber 36 above the piston 22 is on the one hand in fluid communication via a pressure line 10 with a pressure volume chamber 18 in a pre-acceleration cylinder 13 which is fixed to the press.
  • a follow-up line 12 is led into the pressure chamber 36, from which hydraulic fluid can flow in the pressure chamber 36 when suction pressure occurs.
  • the pressure spaces 9 in the pressure cylinders 7 are in flow connection separately from one another via pressure lines 11, each with a pressure volume space 19 in the pre-acceleration cylinder 13.
  • a follow-up line 12 is led into the pressure chambers 9, from which hydraulic fluid can flow in the pressure chambers 9 when suction pressure occurs.
  • the inflow of hydraulic fluid from a pressure accumulator into the pressure chambers 36 and 9 is accomplished via a throttling directional control valve.
  • the directional control valve which can be a so-called prop valve, is controlled as a function of the position or movement of the ram into the open position.
  • a pressure chamber 14 is assigned to the pressure piston 15, and hydraulic fluid from a pressure accumulator 21 when a valve 20 is switched under high pressure Pressure is supplied.
  • the valve 20 is also a throttling directional control valve and the control is also carried out, for example, from the press control via the control line 35 as a function of the position or movement of the drawing ram.
  • the timing of the directional control valve 20 in the pressure line to the pressure chamber 14 of the pre-acceleration cylinder 13 and the directional control valve in the follow-up line 12 into the pressure chambers 36, 9 can be explained with reference to FIG. 2.
  • the movement characteristics of the ram, plotted against the angle of rotation, are shown in curve 26.
  • the sheet holder with the sheet lying thereon and to be formed into a workpiece must be pre-accelerated in the direction of pull 37 (curve 27) by opening the directional control valve 20 in the pressure line the pressure chamber 14 in the pre-acceleration cylinder 13.
  • the movement of the pressure pistons 16, 17 in the pressure quantity spaces 18, 19 moves a targeted amount of hydraulic fluid via the pressure lines 10, 11 into the pressure spaces 36, 9, so that the pressure pistons 22, 23 in the direction of pull 37 be accelerated.
  • the pre-acceleration phase 28 changes into a suction phase 29 for the pressure chambers 36, 9 when the drawing plunger with the drawing ring hits the sheet metal.
  • the directional valves in the follow-up lines 12 to the pressure chambers 36, 9 must be opened.
  • the suction phase in the pressure chambers 36, 9 ends with the reversal of the movement of the drawing ram and the controlled raising of the pressure cheek 1.
  • the diameters of the pistons 17, 16 in the pressure volume spaces 18, 19 must be set in relation to the active surfaces 33, 34 on the pistons 22, 23 in the pressure spaces 36, 9. It is understood that the pressure pistons 18, 19 can be moved by separate pre-acceleration cylinders 13 for the use of other stroke and pressure conditions. That would be e.g. then given when the pre-acceleration of the sheet metal holder is to be achieved for spatial reasons and for reasons of a low pressure specification.

Description

Die Erfindung betrifft eine Zieheinrichtung für eine Presse der gattungsbildenden Art.The invention relates to a pulling device for a press of the generic type.

Um zu verhindern, daß die Druckwange in einer mit einer Zieheinrichtung ausgerüsteten Presse dem Ziehstößel nach dem Umformen direkt nachläuft, sind für den Auswerfer der Werkstücke und das Festhalten der Werkstücke während des Ziehens verschiedene Druckzylindersysteme vorhanden, die in unterschiedlichen Bereichen an der Druckwange angreifen.In order to prevent the pressure cheek from running directly after the forming ram in a press equipped with a pulling device, various pressure cylinder systems are available for the ejector of the workpieces and the holding of the workpieces during the drawing, which act on the pressure cheek in different areas.

Eine solche Zieheinrichtung ist in der DE-A1-35 05 984 & EP-A-0 192 115 beschrieben. Hierbei sind die verschiedenen Einzelfunktionen der Zieheinrichtung wie Steuern des Blechhalterdrucks, Steuern der Blechhalteraufwärtsbewegung, Steuern der Auswerferbewegung und des Endlagenanschlags voneinander unabhängig einstellbar und steuerbar. Die Zieheinrichtung weist Druckzylinder für die Blechhaltung bei dem Ziehen und Druckzylinder für das Auswerfen der Werkstücke auf sowie eine in dem Pressentisch geführte und durch die Druckzylinder bewegbare und abgestützte Druckwange. Nach dem Arbeitshub des Ziehstößels kommen Nachlaufregeleinrichtungen zur Wirkung für einen zeitlich unabhängigen Hochlauf von Auswerfer- und Ziehkolbenstangen. Die Ziehkolbenstangen sind hierfür von der Unterseite der Druckwange lösbar.Such a pulling device is described in DE-A1-35 05 984 & EP-A-0 192 115. The various individual functions of the pulling device, such as controlling the sheet holder pressure, controlling the upward movement of the sheet holder, controlling the ejector movement and the end position stop, are independently adjustable and controllable. The drawing device has pressure cylinders for sheet metal holding during the drawing and pressure cylinders for ejecting the workpieces, as well as a pressure cheek guided in the press table and movable and supported by the pressure cylinders. After the working stroke of the drawing ram, follow-up control devices come into effect for a time-independent ramp-up of ejector and drawing piston rods. The drawing piston rods can be detached from the underside of the pressure cheek.

Bei dem Arbeitshub des Ziehstößels der Presse wird zunächst das in das Werkzeug eingelegte Blech durch den Ziehring gegen dem Blechhalter gedrückt und danach zusammen mit dem Blechhalter entgegen der von der Zieheinrichtung aufgebrachten Haltekraft verschoben. Neben der von der Zieheinrichtung aufzubringenden haltekraft muß der Ziehstößel auch die Massenträgheitskräfte, die durch die Beschleunigung der beweglichen Massen von Blechhalter und Zieheinrichtung zum Anfang der Verformung zur Wirkung kommen, überwinden.During the working stroke of the ram of the press, the sheet inserted into the tool is first pressed against the sheet holder by the drawing ring and then moved together with the sheet holder against the holding force exerted by the drawing device. In addition to the holding force to be exerted by the pulling device, the ram must also overcome the inertial forces which come into effect as a result of the acceleration of the movable masses of the sheet metal holder and pulling device at the beginning of the deformation.

Zur Vermeidung dieser schlagartig auftretenden Belastung auf den Ziehstößel ist es bei der Zieheinrichtung nach der EP-A1-0 074 421 bekannt, die mehrere Druckstangen für den Blechhalter tragende Druckwange über eine druckmittelbeaufschlagbare Kolbenstange eines pressenfesten Druckzylinders zu bewegen. Die Kolbenstange ist mit einem Druckkolben wirkverbunden, der eine in Ziehrichtung beaufschlagbare Wirkfläche aufweist. Die Wirkfläche ist über eine stößelwegabhängig arbeitende Steuerung direkt aus einem Druckspeicher beaufschlagbar, so daß hierdurch vor dem Aufsetzen des Ziehstößels auf den Blechhalter dieser in Ziehrichtung vorbeschleunigbar ist. Die Bewegung der Kolbenstange der Zieheinrichtung in der Vorbeschleunigungsphase ist zeitgesteuert und läßt eine Vorbeschleunigung von getrennt angeordneten und wirkenden Zieh- und Auswerferkolben nicht erkennen.In order to avoid this sudden load on the ram, it is known in the pulling device according to EP-A1-0 074 421 to move the pressure cheek carrying a plurality of pressure rods for the sheet metal holder via a piston rod of a pressurized pressure cylinder which can be pressurized with pressure medium. The piston rod is operatively connected to a pressure piston which has an active surface which can be acted upon in the direction of pull. The active surface can be acted upon directly from a pressure accumulator via a control that operates depending on the ram, so that this allows the drawing ram to be pre-accelerated in the direction of drawing before the drawing ram is placed on it. The movement of the piston rod of the pulling device in the pre-acceleration phase is time-controlled and does not reveal a pre-acceleration of pulling and ejection pistons which are arranged and act separately.

Demgegenüber ist es Aufgabe der Erfindung, ausgehend von Stand der Technik nach dem Oberbegriff des Anspruchs 1 die Vorbeschleunigung der Kolbenstangen für den Blechhalterdruck und den Auswerferbetrieb in Ziehrichtung über gezielt vorgegebene, dosierte Mengen an Hydraulikflüssigkeit zu steuern.In contrast, it is an object of the invention, starting from the prior art according to the preamble of claim 1, to control the pre-acceleration of the piston rods for the sheet metal holder pressure and the ejector operation in the direction of drawing via specifically predetermined, metered amounts of hydraulic fluid.

Diese Aufgabe wird gelöst durch die im Anspruch 1 angegebene Lösung. Die Merkmale der weiteren Ansprüche beinhalten bevorzugte Ausgestaltungen.This object is achieved by the solution specified in claim 1. The features of the further claims contain preferred configurations.

Von besonderem Vorteil hierbei ist die mengenmäßige Steuerung der Vorbeschleunigung der Kolbenstangen in Ziehrichtung und die über ein im Querschnitt veränderbares Wegeventil beeinflußbare Vorsteuerung über einen Vorbeschleunigungszylinder. Die synchrone Vorbeschleunigung ist durch die Trennung der Druckräume voneinander gewährleistet. Es werden Druckschwingungen zwischen dem Blech und dem Blechhalter unterbunden. Das Blech wird bereits im Beginn der Ziehphase gleichmäßig gehalten.Of particular advantage here is the quantitative control of the pre-acceleration of the piston rods in the direction of pull and the pre-control via a pre-acceleration cylinder, which can be influenced by a directional control valve which can be changed in cross section. The synchronous pre-acceleration is guaranteed by the separation of the pressure chambers from each other. Pressure vibrations between the sheet and the sheet holder are prevented. The sheet is held evenly at the start of the drawing phase.

Im folgenden wird die Erfindung anhand eines Ausführungsbeispiels in der Zeichnung erläutert.The invention is explained below using an exemplary embodiment in the drawing.

Dabei zeigen

Fig. 1
einen Vertikalschnitt durch die Zieh-, Auswerfer-und Vorbeschleunigungseinrichtungen und
Fig. 2
ein Diagramm der Ziehstößel- und Blechhalterbewegung.
Show
Fig. 1
a vertical section through the pulling, ejector and pre-acceleration devices and
Fig. 2
a diagram of the ram and sheet metal holder movement.

Die Zieheinrichtung in Fig. 1 weist eine Anzahl an Druckzylindern 3 für die Blechhaltung und zumindest einen Druckzylinder 5 für das Auswerfen des jeweils geformeten Werkstücks auf. Die Druckzylinder 3 und 5 sind über eine Konsole 8, die Teil des Pressentisches sein kann, gehalten und wirken über ihre Kolbenstangen 4 und 31 von unten auf die Druckwange 1. Die Kolbenstangen 4 sind von der Unterseite der Druckwange 1 für den Auswerferbetrieb lösbar. Mit 30 bzw. 32 sind Kugelpfannen angedeutet. Oberhalb der Druckwange 1 sind Druckstangen 2 gezeigt, die in das Ziehwerkzeug auf dem Pressentisch eingreifen und gegen den Blechhalter bzw. ein Auserferelement gelegt sind. Die Kolbenstangen 4 bzw. 31 sind nach unten verlängert und reichen bis in jeweils einen zusätzlichen weiteren Druckzylinder 6 bzw. 7. Im Hinblick auf die unterschiedlich aufzubringenden Druckkräfte in den Kolbenstangen 31, 4 bei dem Ziehen sind die Durchmesser der mit den Kolbenstangen 31, 4 mitgeführten Kolben 22 bzw. 23 unterschiedlich groß, wenn z.B. gleiche Druckverhältnisse in den Druckzylindern 6, 7 herrschen sollen. Oberhalb jedes der Druckkolben 22, 23 ist jeweils ein Druckraum 36 bzw. 9 vorgesehen, bei deren Druckbeaufschlagung die eigentliche Wirkfläche 33 bzw. 34 jedes Kolbens 22, 23 und somit die Kolbenstangen 31, 4 in Ziehrichtung 37 bewegt werden. Anschläge 25 begrenzen die Bewegung der Kolbenstangen 31, 4 in der Aufwärtsbewegung. Der Druckraum 36 oberhalb des Kolbens 22 steht einerseits über eine Druckleitung 10 mit einem Druckmengenraum 18 in einem pressenfesten Vorbeschleunigungszylinder 13 in Fließverbindung. Andererseits ist eine Nachlaufleitung 12 in den Druckraum 36 geführt, aus der bei auftretendem Saugdruck in dem Druckraum 36 Hydraulikflüssigkeit nachfließen kann. Die Druckräume 9 in den Druckzylindern 7 stehen getrennt voneinander einerseits über Druckleitungen 11 mit je einem Druckmengenraum 19 in dem Vorbeschleunigungszylinder 13 in Fließverbindung. Andererseits ist je eine Nachlaufleitung 12 in die Druckräume 9 geführt, aus der bei auftretendem Saugdruck in den Druckräumen 9 Hydraulikflüssigkeit nachfließen kann. Der Nachfluß von Hydraulikflüssigkeit aus einem Druckspeicher in die Druckräume 36 und 9 wird jeweils über ein drosselndes Wegeventil bewerkstelligt. Das Wegeventil, das ein sog. Prop-Ventil sein kann, wird in Abhängigkeit von der Stellung bzw. Bewegung des Ziehstößels in die Offen-Stellung gesteuert.The drawing device in FIG. 1 has a number of printing cylinders 3 for sheet metal holding and at least one printing cylinder 5 for ejecting the shaped workpiece. The pressure cylinders 3 and 5 are held by a bracket 8, which can be part of the press table, and act on the pressure cheek 1 from below via their piston rods 4 and 31. The piston rods 4 can be detached from the underside of the pressure cheek 1 for ejector operation. Ball sockets are indicated by 30 and 32 respectively. Above the pressure beam 1, pressure rods 2 are shown, which engage in the drawing tool on the press table and are placed against the sheet metal holder or an Auserfer element. The piston rods 4 and 31 are extended downward and extend into an additional additional pressure cylinder 6 and 7, respectively. With regard to the pressure forces to be applied differently in the piston rods 31, 4 during pulling, the diameters are those with the piston rods 31, 4 Pistons 22 and 23 carried along are of different sizes if, for example, the same pressure conditions are to prevail in the pressure cylinders 6, 7. A pressure chamber 36 and 9 is provided above each of the pressure pistons 22, 23, the actual effective surface 33 and 34 of each piston 22, 23 and thus the piston rods 31, 4 being moved in the direction of pull 37 when they are pressurized. Stops 25 limit the movement of the piston rods 31, 4 in the upward movement. The pressure chamber 36 above the piston 22 is on the one hand in fluid communication via a pressure line 10 with a pressure volume chamber 18 in a pre-acceleration cylinder 13 which is fixed to the press. On the other hand, a follow-up line 12 is led into the pressure chamber 36, from which hydraulic fluid can flow in the pressure chamber 36 when suction pressure occurs. The pressure spaces 9 in the pressure cylinders 7 are in flow connection separately from one another via pressure lines 11, each with a pressure volume space 19 in the pre-acceleration cylinder 13. On the other hand, a follow-up line 12 is led into the pressure chambers 9, from which hydraulic fluid can flow in the pressure chambers 9 when suction pressure occurs. The inflow of hydraulic fluid from a pressure accumulator into the pressure chambers 36 and 9 is accomplished via a throttling directional control valve. The directional control valve, which can be a so-called prop valve, is controlled as a function of the position or movement of the ram into the open position.

In die Druckmengenräume 18, 19 tauchen Druck- oder Plungerkolben 16, 17, die mit einem Druckkolben 15 starr verbunden sind. Dem Druckkolben 15 ist ein Druckraum 14 zugeordnet, dem aus einem Druckspeicher 21 bei Schaltung eines Ventils 20 Hydraulikflüssigkeit unter hohem Druck zugeführt wird. Das Ventil 20 ist gleichfalls ein drosselndes Wegeventil und die Ansteuerung erfolgt gleichfalls beispielsweise von der Pressensteuerung aus über die Steuerleitung 35 in Abhängigkeit von der Stellung bzw. Bewegung des Ziehstößels.Pressure or plunger pistons 16, 17, which are rigidly connected to a pressure piston 15, plunge into the pressure quantity spaces 18, 19. A pressure chamber 14 is assigned to the pressure piston 15, and hydraulic fluid from a pressure accumulator 21 when a valve 20 is switched under high pressure Pressure is supplied. The valve 20 is also a throttling directional control valve and the control is also carried out, for example, from the press control via the control line 35 as a function of the position or movement of the drawing ram.

Die zeitliche Steuerung des Wegeventils 20 in der Druckleitung zu dem Druckraum 14 des Vorbeschleunigungszylinders 13 und des Wegeventils in der Nachlaufleitung 12 in die Druckräume 36, 9 ist anhand der Fig. 2 zu erläutern. Die Bewegungscharakteristik des Ziehstößels, aufgetragen über dem Drehwinkel, zeigt Kurve 26. Während des Arbeitshubes des Ziehstößels ist der Blechhalter mit dem auf diesem aufliegenden, in ein Werkstück umzuformenden Blech in Ziehrichtung 37 vorzubeschleunigen (Kurve 27) durch Öffnen des Wegeventils 20 in der Druckleitung zu dem Druckraum 14 im Vorbeschleunigungszylinder 13. Durch die Bewegung der Druckkolben 16, 17 in den Druckmengenräumen 18, 19 wird eine gezielte Menge Hydraulikflüssigkeit über die Druckleitungen 10, 11 in die Druckräume 36, 9 bewegt, so daß die Druckkolben 22, 23 in Ziehrichtung 37 beschleunigt werden. Die Vorbeschleunigungsphase 28 geht mit dem Auftreffen des Ziehstößels mit Ziehring auf dem Blech in eine Saugphase 29 für die Druckräume 36, 9 über. Hierzu sind die Wegeventile in den Nachlaufleitungen 12 zu den Druckräumen 36, 9 zu öffnen. Die Saugphase in den Druckräumen 36, 9 endet mit der Umkehr der Bewegung des Ziehstößels und dem gesteuerten Hochbringen der Druckwange 1.The timing of the directional control valve 20 in the pressure line to the pressure chamber 14 of the pre-acceleration cylinder 13 and the directional control valve in the follow-up line 12 into the pressure chambers 36, 9 can be explained with reference to FIG. 2. The movement characteristics of the ram, plotted against the angle of rotation, are shown in curve 26. During the working stroke of the ram, the sheet holder with the sheet lying thereon and to be formed into a workpiece must be pre-accelerated in the direction of pull 37 (curve 27) by opening the directional control valve 20 in the pressure line the pressure chamber 14 in the pre-acceleration cylinder 13. The movement of the pressure pistons 16, 17 in the pressure quantity spaces 18, 19 moves a targeted amount of hydraulic fluid via the pressure lines 10, 11 into the pressure spaces 36, 9, so that the pressure pistons 22, 23 in the direction of pull 37 be accelerated. The pre-acceleration phase 28 changes into a suction phase 29 for the pressure chambers 36, 9 when the drawing plunger with the drawing ring hits the sheet metal. For this purpose, the directional valves in the follow-up lines 12 to the pressure chambers 36, 9 must be opened. The suction phase in the pressure chambers 36, 9 ends with the reversal of the movement of the drawing ram and the controlled raising of the pressure cheek 1.

Um eine gleiche Vorbeschleunigung aller Kolbenstangen 31, 4 zu erreichen, sind die Durchmesser der Kolben 17, 16 in den Druckmengenräumen 18, 19 in Verhältnis der Wirkflächen 33, 34 an den Kolben 22, 23 in den Druckräumen 36, 9 einzustellen. Es versteht sich, daß für die Nutzung anderer Hub- und Druckverhältnisse die Druckkolben 18, 19 durch getrennte Vorbeschleunigungszylinder 13 bewegt werden können. Das wäre z.B. dann gegeben, wenn aus räumlichen Gründen und aus Gründen einer niedrigen Druckvorgabe die Vorbeschleunigung des Blechhalters erreicht werden soll.In order to achieve the same pre-acceleration of all piston rods 31, 4, the diameters of the pistons 17, 16 in the pressure volume spaces 18, 19 must be set in relation to the active surfaces 33, 34 on the pistons 22, 23 in the pressure spaces 36, 9. It is understood that the pressure pistons 18, 19 can be moved by separate pre-acceleration cylinders 13 for the use of other stroke and pressure conditions. That would be e.g. then given when the pre-acceleration of the sheet metal holder is to be achieved for spatial reasons and for reasons of a low pressure specification.

Claims (4)

  1. Drawing device for a press with a mechanically moved drawing slide and with a plate holder, with pressure cylinders (3) for plate holding during the drawing, with at least one pressure cylinder (5) for the ejection of the workpiece, and with a pressure cheek (1) movable in the press platen (8) by the piston rods (4, 31) of the pressure cylinders (3, 5) and transmitting the movement and forces of the pressure cylinders (3, 5) to the plate holder via pressure rods (2), characterised in that each piston rod (31, 4) has a pressure piston (22, 23) with an effective surface (33, 34) loadable in the drawing direction (37), in that each of the pressure spaces (36, 9) assigned to an effective surface (33, 34) has a flow connection on the one hand with a pressure-quantity space (18, 19) of a preacceleration cylinder (13) composed of the pressure-quantity space (18, 19), a pressure space (14) and a pressure piston (15) separating these spaces (14, 18, 19) from one another, and in that the or each pressure space (14) can be loaded with pressure via a throttling directional valve (20) by a control working as a function of the slide travel, with the result that, before the drawing slide is applied to the plate holder, the latter can be preaccelerated in the drawing direction (37) by loading the effective surfaces (33, 34) with hydraulic fluid from the pressure-quantity spaces (18, 19).
  2. Drawing device according to Claim 1, characterised in that each pressure space (36, 9) assigned to an effective surface (33, 34) on the piston rods (31, 4) has a flow connection with a respective pressure-quantity space (18, 19), and in that the pressure pistons (16, 17) interacting with the pressure-quantity spaces (18, 19) are jointly movable by the pressure piston (15) of a preacceleration cylinder (13).
  3. Drawing device according to Claim 2, characterised in that the pressure space (14) in the preacceleration cylinder (13) can be brought into flow connection with a pressure source (21) via a throttling directional valve (20), and the directional valve (20) can be switched by the press control working as a function of the slide travel.
  4. Drawing device according to one or more of the aforesaid claims, characterised in that, for the same stroke of the pressure pistons (16, 17) in the pressure-quantity spaces (18, 19), the diameter ratios of the pressure pistons (16, 17) to one another correspond to the surface ratios of the effective surfaces (33, 34) of the pressure pistons (23, 23) in the pressure cylinders (6, 7) to one another.
EP87116280A 1986-11-28 1987-11-05 Drawing device for a press Expired - Lifetime EP0268894B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863640787 DE3640787A1 (en) 1986-11-28 1986-11-28 DRAWING DEVICE FOR A PRESS
DE3640787 1986-11-28

Publications (3)

Publication Number Publication Date
EP0268894A2 EP0268894A2 (en) 1988-06-01
EP0268894A3 EP0268894A3 (en) 1989-11-29
EP0268894B1 true EP0268894B1 (en) 1992-08-12

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP87116280A Expired - Lifetime EP0268894B1 (en) 1986-11-28 1987-11-05 Drawing device for a press

Country Status (5)

Country Link
US (1) US4821552A (en)
EP (1) EP0268894B1 (en)
CA (1) CA1291372C (en)
DE (2) DE3640787A1 (en)
ES (1) ES2033769T3 (en)

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US5003807A (en) * 1989-10-30 1991-04-02 Teledyne Industries, Inc. Press assembly and method of operation
DE4218914A1 (en) * 1992-06-10 1993-12-16 Erfurt Umformtechnik Gmbh Hydraulic pulling device in a press
US5457980A (en) * 1992-11-05 1995-10-17 Toyota Jidosha Kabushiki Kaisha Method and device for controlling, checking or optimizing pressure of cushion pin cylinders of press by discharging fluid or initial pressure
DE69331974T2 (en) * 1992-11-05 2003-01-23 Toyota Motor Co Ltd METHOD AND DEVICE FOR REGULATING CHECKING OR OPTIMIZING THE PRESSURE OF A CYLINDER PIN BY A LIQUID OR INITIAL PRESSURE EXHAUST
JP2776196B2 (en) * 1993-04-28 1998-07-16 トヨタ自動車株式会社 Diagnosis method and device for pressure equalizing cushion device
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JP2812201B2 (en) * 1994-07-15 1998-10-22 トヨタ自動車株式会社 Press equipment
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Also Published As

Publication number Publication date
EP0268894A3 (en) 1989-11-29
EP0268894A2 (en) 1988-06-01
US4821552A (en) 1989-04-18
DE3640787A1 (en) 1988-06-01
ES2033769T3 (en) 1993-04-01
CA1291372C (en) 1991-10-29
DE3781099D1 (en) 1992-09-17

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