WO1980002239A1 - Dispositif pour presses - Google Patents

Dispositif pour presses Download PDF

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Publication number
WO1980002239A1
WO1980002239A1 PCT/SE1979/000093 SE7900093W WO8002239A1 WO 1980002239 A1 WO1980002239 A1 WO 1980002239A1 SE 7900093 W SE7900093 W SE 7900093W WO 8002239 A1 WO8002239 A1 WO 8002239A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
movement
function generator
values
hydraulic
Prior art date
Application number
PCT/SE1979/000093
Other languages
English (en)
Inventor
H Folkesson
U Oeberg
Original Assignee
Saab Scania Ab
H Folkesson
U Oeberg
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 Saab Scania Ab, H Folkesson, U Oeberg filed Critical Saab Scania Ab
Priority to PCT/SE1979/000093 priority Critical patent/WO1980002239A1/fr
Priority to DE19792953438 priority patent/DE2953438A1/de
Priority to JP50075579A priority patent/JPS6031600B2/ja
Publication of WO1980002239A1 publication Critical patent/WO1980002239A1/fr

Links

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
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/22—Control arrangements for fluid-driven presses controlling the degree of pressure applied by the ram during the pressing stroke
    • 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
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/10—Stamping using yieldable or resilient pads
    • B21D22/12—Stamping using yieldable or resilient pads using enclosed flexible chambers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/26—Programme control arrangements

Definitions

  • the present invention relates to an arrangement for presses preferably intended for forming sheet metal blanks and with which the forming is effected by hydraulic pressure which varies during a pressing operation, and which comprise a pair of relatively movable components which are made to carry out a relative movement during the pressing operation, means for sensing the said movement and generating a control signal which, according to a functional relationship relevant to the pressing operation, depends on the sensed movement, and a hydraulic system for regulating by means of the control signal the hydraulic pressure so that this may be varied during the pressing operation according to the functional relationship.
  • the in ⁇ vention relates to an improved arrangement for controlling the hydraulic working pressure which acts in such a press during a pressing opera- tion and which thereby controls, either directly or indirectly, the course of the operation.
  • Pressure control of this kind in a press may be considered necessary so that satisfactory working results may be obtained when carrying out deep drawing and similar pressing operations when sheet metal blanks are to be given a complicated form.
  • various solution may be found on the market, based on drawing a curve which represents on a specific scale the relationship between the hydraulic pressure and the movements carried out which has been found to be suitable for a pressing operation.
  • a templet is then produced from 'plate or another rigid material so that the contour of this corresponds accurately with the curve and this templet is fixed to a movable means appertaining to the press which detects the movements involved, in a mechanical way.
  • a templet sensor transmits during the pressing operation the lateral movements obtained from the displacements of the templet to a signal generator in the form of a pressure control valve or a potentiometer which controls an electro-hydraulic valve via an amplifier.
  • a signal generator in the form of a pressure control valve or a potentiometer which controls an electro-hydraulic valve via an amplifier.
  • a templet-sensing arrangement for hydraulic presses which works with photocells is know from Patent 322 193.
  • the templet which, as in the above-described arrangement, is displaced by one of the moving components of the press, can be made in this instance from a piece of paper which is cut so that it gives the desired pressure curve and which is theninserted in a holder so that depending on its movement, light from a light source located on one side of the temple s screened from or reaches a row of photocells arranged on the other side.
  • the arrangement requires that every time a new part is to be produced a templet must be made or the pressure curve adjusted on an existing one, if it is not desired to file all the templets used for future use, and the procedure for trimming a pressure curve into shape is basically juslas labour and time-consuming as with a conventional templet made of plate, for in this case as well the
  • _OMPI W1 templet must be removed from the machine for each modification of the pressure values and after adjustment, which can be effected by cutting away or sticking on -a piece of paper along the contour of the pattern, this must be inserted again in its place in the holder.
  • Another aim which the invention seeks to achieve is to generate the control signal which represents the working pressure in such a way that it is not subject to errors on the grounds of inaccurate movement sensing, mechanical wear, etc., that the course of a pressing operation can be followed visually, and thus the movement and pressure values prevailing at any given moment according to the relevant relationship can be observed, and that the latter can be reproduced for filing, when applied, without preventing the same relationship being used in the production process.
  • the said means comprise a manually programm ⁇ able electric function generator which has a large number of contact points arranged in rows and columns for reproducing in electrically readable form pairwise associated pressure and move- ment values constituting points in the relevant functional rela ⁇ tionship and which at its output is connected to the hydraulic system, while its input side is operatively connected via an electrical measurement transducer to either of the said components so that it receives a measurement signal which is a measure of the movement covered and which makes the function generator in turn and in sequence read off and produce at its output the said pressure values as the movement values are reached.
  • the function generator consists preferably of a programming panel, the electrical parts of which comprise in a known way two crossing .systems of parallel conductors situated in different planes, which are separately assigned to the pressure or movement values respec ⁇ tively which increase stepwise and gradually within each system, from a common starting point.
  • the panel also has in a known way a perforated board covering the conductor systems, the holes in which are located right at the intersection points of the system, and suitable plug contacts for fitting in the holes.
  • the pro- c ⁇ dure is to insert, for each of the movement values, a plug contact in the hole which corresponds with a selected demand pressure value so that the plug contact positions on the panel depict as a whole the pressure curve believed to be suitable for a certain pressing operation. If the working results are not satis- factory it is possible:with ' a.few. ma ⁇ upulatio ⁇ s to.adjust the curve rapidly, by moving one or more of the plugs so that the demand value of the hydraulic pressure for a specific relative position of the movable components of the press -or during a certain part of the total forming movement is raised or lowered compared with the former value.
  • Each functional relationship programmed in this way can be recorded easily and rapidly for filing by providing the programming panel with a diagram sheet which is pierced by the plug contacts as they are inserted in the holes in the panel.
  • the function generator has a row of lamps or the like which are lit in turn in time with the sensed movement values. In this way, the operator can easily check the progress of a pressing operation.
  • Figure 1 is an axial section through a hydraulic press with the arrangement accord- ing to the invention
  • Figure 2 is an electrical circuit diagram of the arrangement
  • Figure 3 illustrates a programmed relationship between the forming movements and the pressure.
  • the stand 1 On its lower section the stand 1 bears a hydraulic assembly 6 comprising a cylinder 7 in which an outer pressing piston 8 is inserted, which passes at the top via an intermediate base 9 into a draw ring 10 on which the sheet metal blank 3 is placed when the press is in the open position.
  • the hydraulic assembly also has an inner piston 11 which bears a central tool component, in this instance constructed as a die 12.
  • the chambers 13 and 14 underneath the outer and inner pistons respecti ⁇ vely are filled with hydraulic fluid and are connected via pressure lines 15 and 16 to a hydraulic syste • comprising a pump assembly 17.
  • the hydraulic system is designed to effect all the fluid transporta ⁇ tion which is required for closing the press, whereby during the expansion of the fluid chamber 13 the outer piston 8 moves upwards into the position shown in the Figure, bringing the inner piston 11 with it; similarly, for opening the press, pressure medium is introduced into the two annular chambers 18 and 19 which are located between the cylinder 7 and the outer piston, and between the other piston and the inner piston respectively, at the same time as the chamber 13 is compressed.
  • the forming operation itself is effected, as is known in this kind of press, in that the inner piston 11 together with the die 12 is made to move upwards by the supply of pressure fluid from the pumping assembly 17 via the line 16 into the chamber 14, so that the sheet metal blank 3 is drawn over the die and deformed.
  • a high fluid pressure arises in the forming chamber 5, which leads to the result that under the influence of the membrane 4 the sheet metal blank is pressed against all sides of the die and assumes the shape thereof, and in addition the casing of the unit 2, the draw ring 10 which rests thereon and the outer piston 8 move downwards during the draining of fluid from the chamber 13
  • the specific pressure in the forming chamber 5 is of great importance for the working results and it has been found that this pressure should be controlled so that it varies in a specific way with the mutual movement of the tool components, that is, as a function of the relative movements between the outer piston 8 and the inner piston 11, which parts are hereinafter called the two moveable components of the press.
  • One way proposed to accomplish this pressure control is to allow the fluid which is drained from the hydraulic assembly 6 during forming to pass through a valve arrangement 20 which ensures that the pressure upstream from the valve arrangement and with it the pressure in the fluid chamber which is compressed during forming (i.e.
  • the chamber 13 in the example of die-forming corresponds to a demand value which varies depending on the mutual displacement of the two • movable components of the press. Accordingly, the valve arrangement indirectly controls the fluid pressure which is effective in the forming chamber 5.
  • the fluid drained off in this way can either go to a tank 21 or, as described in Patent (patent
  • the measurement transducer 22 which is assumed to be the type of optical absolute position transducer which produces a digitally coded measurement signal, comprises a grid disc 24 which is attached rotatably but not displaceably to the intermediate base 9, and a rod 25 which rotates the grid disc and which is attached to the inner piston 11 by means of a bracket 26.
  • This projects out laterally through a slit 27 in the draw ring 10 and has a vertical extent such that the bracket can move freely relative to the draw ring at the upwards displacement of the in.ner piston.
  • the grid disc thereby rotates through an angle which exactly corresponds to the mutual displacement between the two moving components 8 and 11 and which is una bignously represented by the digital measurement signal which is supplied to the input 28 of the function generator.
  • an analogue position transducer for example, a contact-free potentiometer, from being used instead, when naturally another adaptation may be effected between the position transducer and the function generator.
  • the function generator comprises advantageously a conventional programming panel 29 with conducting systems which cross each other, which are located in separate planes so that the conductors themselves do not provide any link between the systems.
  • Each system comprises a large number of equidistantly located, conductors (of which only a small number are shown in the drawing), together forming a regular checked pattern, the rows 30 and columns 31 of which represent pressure and movement values respectively, all gradually increasing in small steps from the lower left-hand corner 32 of the panel.
  • a plug contact 34 By fitting a plug contact 34 in a hole, the two row and column conductors which pass inside it are connected to each other, thus allowing a point in a desired function relationship to be programmed in the function generator.
  • the function values corresponding to the positions of the holes should be given, the pressure values expediently in percent of the maximum operating pressure of the press, and displacement values in appropriate units of length.
  • the programming panel is also provided with an illuminated array 35, the lamps 36 of which are associated one by on with the columns of the panel and are connected to a decoder 37 which receives measurement signals from the position transducer 22 and which is designed to light the lamps 36 in turn and in sequence as the movement values corresponding to the columns are obtained.
  • the function generator has a second decoder 38 which is connected to each of the column conductors 31 via a gate 39, and which is designed so that, during a forming operation, it acti ⁇ vates one of the column conductors with the aid of the measurement signal received, which will occur in the same sequence and at the same moment as the corresponding lamp 36 is lit.
  • This activation can be effected so that the conductor in question is connected to electrical earth by means of its gate while all the remaining column conductors remain inactive due to the fact that their gates have a high impedance to earth.
  • the output side of the function generator comprises a resistance chain 40 in which each separate resistance is connected between a pair of adjacent conductors in the rows 30, and has a resistance value such that the series resistance- for the chain increases, preferably by the same amount at each step and calculated from the therminal point 41 according to the pressure values appertaining to the rows.
  • a current generator 42 connected to the terminal point provides a current with constant current strength and while forming is going on, this current can be conducted to earth only via the column conductor which is activated at that moment.
  • a voltage with such a characteristic is not, however, used directly for controlling the pressure, but is first modified, according to a characteristic feature of the invention, into a continuously varying signal, this being effected in a filter 43.
  • This can consist of a RC circuit with a variable condenser and by using this to adjust the filter time-constant in relation to the prevailing relative speed of the moving components in the press, it is possible to smooth, at least to a large extent, the stepwise variation in the direct current produced in the function generator at the transition from one column 31 to another.
  • the valve arrangement 20 comprises a pressure regulating valve 44 the characteristic of which is such that the pressure is proportional to the current in a spool 45 in the valve, it can be expedient to process the filtered direct current signal in the following way.
  • an oscillator 46 an alternating current is produced which has a small amplitude compared with the direct current and which is superimposed on the latter in an operation amplifier 47 so that, in a .known way, the mechanical hysteresis of the pressure control valve, or its tendency to stick, is eliminated.
  • the summing signal the mean current value of which is unchanged compared with the current at the point 41 , is applied to another operation amplifier 48 where it is compared with the voltage across a resistance 49 with low
  • the pressure control valve is operated as a pilot valve controlling a main valve 52. This is dimensioned in such a way that it is capable of taking over all or most of the stream of fluid which is to be drained from the press into the tank 21 or is to circulate from one fluid chamber 13 in the press, through the valve to the other fluid chamber 14.
  • the diagram paper is attached in the correct position on the board after which the actual pressure curve is transferred to the paper by the plug contacts 34 being pressed through the paper so that they make a series of holes 56 corresponding with the programmed points.

Abstract

Une presse fonctionnant avec une pression hydraulique comprend une paire de composants mobiles l'un par rapport a l'autre (8, 11) qui, pendant une operation de pressage, effectuent un mouvement relatif qui est detecte. Un signal de commande produit au moyen du mouvement relatif detecte est utilise pour regler la pression hydraulique que l'on fait varier avec le mouvement relatif selon une certaine relation fonctionnelle. Pour produire le signal de commande, un generateur de fonctions electrique programmable manuellement (23) est prevu; un panneau (29) comprenant des contacts a fiche (34), sur lequel une pluralite de valeurs associees par paires de pression et mouvement, constituant des points electriquement et visuellement visibles dans la relation fonctionnelle desiree, peut etre installe. A l'entree (28) du generateur de fonctions est delivre un signal de mesure qui represente une mesure du mouvement relatif couvert par les deux composants et qui fait lire le generateur de fonctions et lui fait produire (24, 41-43) les valeurs de pression lorsque les valeurs determinees du mouvement correspondant a celles-ci sont atteintes.
PCT/SE1979/000093 1979-04-17 1979-04-17 Dispositif pour presses WO1980002239A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/SE1979/000093 WO1980002239A1 (fr) 1979-04-17 1979-04-17 Dispositif pour presses
DE19792953438 DE2953438A1 (de) 1979-04-17 1979-04-17 An arrangement for presses
JP50075579A JPS6031600B2 (ja) 1979-04-17 1979-04-17 プレス機械

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PCT/SE1979/000093 WO1980002239A1 (fr) 1979-04-17 1979-04-17 Dispositif pour presses
WOSE79/00093 1979-04-17

Publications (1)

Publication Number Publication Date
WO1980002239A1 true WO1980002239A1 (fr) 1980-10-30

Family

ID=20336940

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1979/000093 WO1980002239A1 (fr) 1979-04-17 1979-04-17 Dispositif pour presses

Country Status (3)

Country Link
JP (1) JPS6031600B2 (fr)
DE (1) DE2953438A1 (fr)
WO (1) WO1980002239A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356763A (en) * 1980-06-30 1982-11-02 Aktiebolaget Karlstads Mekaniska Werkstad Control arrangements for hydraulically-operated wood particle or fiber board press
DE19718579A1 (de) * 1997-05-05 1998-11-12 Claas Usines France Steuerung zur Regelung der Preßkraft einer Großballenpresse
ES2184579A1 (es) * 2000-11-13 2003-04-01 Canellas Rafael Sitjar Prensa rotativa para la fabricacion de comprimidos.

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE456458B (sv) * 1983-07-12 1988-10-03 Nobel Elektronik Ab Reglerkrets

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2693780A (en) * 1951-02-10 1954-11-09 Glenn L Martin Co Pressure controlled forming apparatus
DE1227126B (de) * 1960-08-25 1966-10-20 Heid Ag Maschf Steuereinrichtung fuer Arbeitsmaschinen, insbesondere Werkzeugmaschinen
SE300099B (fr) * 1964-01-30 1968-04-08 Asea Ab
GB1162504A (en) * 1965-12-20 1969-08-27 Asea Ab Improvements in the Control of Hydraulic Presses.
FR1600859A (fr) * 1967-08-24 1970-08-03
CH570653A5 (fr) * 1973-07-21 1975-12-15 Lechler Apparatebau Kg
GB1426099A (en) * 1972-06-09 1976-02-25 Eumuco Ag Fuer Maschinenbau Programming method and circuit for controlling manipulator and press ram movement in a forming machine
US3962895A (en) * 1973-12-05 1976-06-15 Saab-Scania Aktiebolag Fluid forming apparatus having controllably variable forming pressure
US3987283A (en) * 1975-07-07 1976-10-19 Moeller Charles R Digital controller for punch presses and the like
DE2656456A1 (de) * 1975-12-16 1977-06-30 Gen Electric Verfahren und vorrichtung zur ueberwachung, analyse und steuerung des betriebs einer dual-plattenpresse
SE401898B (sv) * 1975-05-22 1978-06-05 Saab Scania Ab Regleranordning vid pressar for formning av platemnen medelst ett tryckmedium

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2693780A (en) * 1951-02-10 1954-11-09 Glenn L Martin Co Pressure controlled forming apparatus
DE1227126B (de) * 1960-08-25 1966-10-20 Heid Ag Maschf Steuereinrichtung fuer Arbeitsmaschinen, insbesondere Werkzeugmaschinen
SE300099B (fr) * 1964-01-30 1968-04-08 Asea Ab
GB1162504A (en) * 1965-12-20 1969-08-27 Asea Ab Improvements in the Control of Hydraulic Presses.
FR1600859A (fr) * 1967-08-24 1970-08-03
GB1426099A (en) * 1972-06-09 1976-02-25 Eumuco Ag Fuer Maschinenbau Programming method and circuit for controlling manipulator and press ram movement in a forming machine
CH570653A5 (fr) * 1973-07-21 1975-12-15 Lechler Apparatebau Kg
US3962895A (en) * 1973-12-05 1976-06-15 Saab-Scania Aktiebolag Fluid forming apparatus having controllably variable forming pressure
SE401898B (sv) * 1975-05-22 1978-06-05 Saab Scania Ab Regleranordning vid pressar for formning av platemnen medelst ett tryckmedium
US3987283A (en) * 1975-07-07 1976-10-19 Moeller Charles R Digital controller for punch presses and the like
DE2656456A1 (de) * 1975-12-16 1977-06-30 Gen Electric Verfahren und vorrichtung zur ueberwachung, analyse und steuerung des betriebs einer dual-plattenpresse

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Sven Lundquist "Mekaniska utrustningar", published 1962 by Sveriges Mekanförbund, Stockholm, see pages 89 to 97, especially pages 93 and 94 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356763A (en) * 1980-06-30 1982-11-02 Aktiebolaget Karlstads Mekaniska Werkstad Control arrangements for hydraulically-operated wood particle or fiber board press
DE19718579A1 (de) * 1997-05-05 1998-11-12 Claas Usines France Steuerung zur Regelung der Preßkraft einer Großballenpresse
US6112507A (en) * 1997-05-05 2000-09-05 Usines Claas France Apparatus and method for regulating the baling force in a square baler
ES2184579A1 (es) * 2000-11-13 2003-04-01 Canellas Rafael Sitjar Prensa rotativa para la fabricacion de comprimidos.

Also Published As

Publication number Publication date
JPS56500487A (fr) 1981-04-16
JPS6031600B2 (ja) 1985-07-23
DE2953438A1 (de) 1982-02-11

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