US3559247A - Means for hydraulic presses - Google Patents

Means for hydraulic presses Download PDF

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Publication number
US3559247A
US3559247A US713910A US3559247DA US3559247A US 3559247 A US3559247 A US 3559247A US 713910 A US713910 A US 713910A US 3559247D A US3559247D A US 3559247DA US 3559247 A US3559247 A US 3559247A
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US
United States
Prior art keywords
press head
press
movements
quota
hydraulic
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
US713910A
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English (en)
Inventor
Paul Larsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Norden Holding AB
Original Assignee
ASEA AB
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 ASEA AB filed Critical ASEA AB
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Publication of US3559247A publication Critical patent/US3559247A/en
Anticipated expiration legal-status Critical
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/005—Control arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space

Definitions

  • the present invention relates to a means for hydraulic presses, preferably powder presses, to control their press head movement and that of inbuilt tools.
  • the invention provides a solution of this and other similar problems and is characterised in that movements of both the upper and the lower press heads are sensed by individual position sensing means, the output signals of which, after modification in a quota means, are combined to a comparison signal arranged to control a hydraulic valve for checking the press head movement.
  • a certain required movement ratio can be set between the two press heads and, for example during pressing, gradual or linear adjustment of the movement ratio to the desired value can be automatically obtained.
  • one press head is balanced, preferably the lower, by one or more hydraulic cylinders, the outlets of which are substantially throttled by the hydraulic valve.
  • suitable position sensing means such as potentiometers, and suitable quota means, a potentiometer or a device according to the Swedish patent application No. 16,452/ 65 it is easy to obtain the desired adjustment signal for the hydraulic valve and thus the desired constant or variable movement ratio between upper and lower press heads in order to obtain good quality in the finished product.
  • the invention is exemplified in the accompanying drawing which shows a powder press with an upper movable press head 11 and a lower movable press head 12.
  • a pressure piston 13 In the upper press head 11 is a pressure piston 13, arranged to be pressed down into a mold with a cavity 14 in the power press head 12. Powder material, for instance metal powder is poured into the mold.
  • the lower press head 12 is balanced by two (or some other number) hydraulic cylinders 15 and the powder material in the lower press head 12 is pressed against a stamp 16 in the base. Two pistons (plungers) 17 from the lower press head 12 are inserted and sealed with respect to said balancing cylinders 15.
  • the control equipment used is in principle constructed as a position-servo means where the guiding magnitude is the position of the upper press head 11 and the controlling magnitude is the position of the lower press head 12.
  • the position of the upper press head is sensed in a suitable manner, for example by means of a potentiometer 18, by photo-electric cells, or the like, and output signals from the potentiometer 18 will thus be a measurement of the position of the upper press head 11.
  • the position of the lower press head is sensed in a similar way, for example by means of a potentiometer 19, and the output signal from this potentiometer will be a measurement of the position of the lower press head 12.
  • a second potentiometer 20 is connected in series with one of the potentiometers 18 and the output signals from this potentiometer will thus be k-l, where k is a certain factor set in the potentiometer 20 and if the output signals from potentiometers 20 and 19 are compared, a comparison signal proportional to said factor k is obtained.
  • the device 20 is called a quota means.
  • this means can be arranged with a radiation source and a radiation-sensitive emitter, between which is placed a curved screen of opaque material which influences the output signal from the emitter.
  • the position of the curve is made dependent on the position of one of the press heads and it may be a straight line or be more complicated depending on the desired quota.
  • the latter means is described in Swedish patent application No. 16,452/ 65.
  • Comparison signals are supplied to an integrating amplifier 21, the output side of which is connected to a regulator of suitable type, for example of the type described in Swedish Pat. No. 170,280.
  • a current coil 22 connected to said amplifier 21 the supply of pressure medium to a hydraulic valve 23 connected to the outlet from the hydraulic balancing cylinders 15 is controlled.
  • the various press heads may be included in a larger tool and for each alteration in area of the body a new movable lower press head can be arranged and its position compared with that of the upper press head (not shown).
  • auxiliary pressure cylinders 24 If, during the pressing, the friction of the powder against the walls of the cavity 14 in the tool is not sufiicient, additional pressure is exerted on the powder by auxiliary pressure cylinders 24.
  • the press head can be lifted in a similar manner.
  • the normal pressure is obtained in a main cylinder 25 in a manner known per se.
  • the device operates in the following way:
  • Powder is poured into the mold cavity 14 and pressure is applied on the upper press head 11 in the pressure chamber 25. If there were no control equipment and the powder body and thus the cavity were cylindrical, the lower balanced press head 12 would be pressed down half as far as the upper press head.
  • the desired ratio possibly adjustable during the operation, has been set between the movements of the upper and lower press heads, and even with more complicated bodies an output signal from the amplifier 21 is obtained which corresponds to the deviation from the desired, preset ratio.
  • the hydraulic valve 23 is adjusted in accordance with this value and the balancing pressure in the cylinders is altered in such a way that the movement of the lower press head will be adjusted in relation to that of the upper press head to achieved the desired, preset ratio.
  • the ratio can be set at a constant or variable value according to the shape and material of the powder body.
  • a hydraulic press with inbuilt and movable upper and inbuilt and movable lower press parts, means to control the movements of these parts, comprising sensing means for sensing the movements of the upper part and sensing means for sensing the movements of the lower part, quota means, the output side of one of said sensing means being coupled to said quota means, to furnish an input signal thereto, said quota means including means to multiply the input signal by a constant K, whereby the output signal of said quota means is the product of said constant and the input signal, means to combine the output signal of said quota means and the output signal from the other sensing means, without passing through said quota means, to form a comparison signal, a hydraulic valve for controlling the feed rate of pressure medium to at least one of the movable press parts, control means for said valve, and means to furnish said comparison signal to said control means.
  • the position sensing means comprising otentiometers.
  • the quota means comprising a potentiometer series-connected to one of the position sensing means.
  • the quota means comprising a source of radiation, a radiation sensing emitter and a radiation screening device movably arranged between the source and the emitter.
  • a position measuring potentiometer which is coupled to a potentiometer in the quota means, the output of which is at least indirectly connected to another position measuring potentiometer in order to provide a comparison signal which is fed to an integrating amplifier the output of which controls the feed of pressure medium to the hydraulic valve.
US713910A 1967-03-22 1968-03-18 Means for hydraulic presses Expired - Lifetime US3559247A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE03999/67A SE338241B (de) 1967-03-22 1967-03-22

Publications (1)

Publication Number Publication Date
US3559247A true US3559247A (en) 1971-02-02

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ID=20263314

Family Applications (1)

Application Number Title Priority Date Filing Date
US713910A Expired - Lifetime US3559247A (en) 1967-03-22 1968-03-18 Means for hydraulic presses

Country Status (5)

Country Link
US (1) US3559247A (de)
DE (1) DE1752005B2 (de)
FR (1) FR1556871A (de)
GB (1) GB1210877A (de)
SE (1) SE338241B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742811A (en) * 1970-08-13 1973-07-03 Us Navy Apparatus for controlling the fabrication of electroexplosive devices
US3901635A (en) * 1974-02-08 1975-08-26 Wean United Inc Control system for briquetters
US4035118A (en) * 1973-08-27 1977-07-12 Macmillan Kenneth T Self-centering matrices for retreading molds
US4081910A (en) * 1976-05-19 1978-04-04 Hammond H Jack Shut height gauge and method of using same
US4184827A (en) * 1975-12-16 1980-01-22 General Electric Company Apparatus for monitoring and controlling the operation of a dual platen press
US4199539A (en) * 1975-12-16 1980-04-22 General Electric Company Method for monitoring and controlling the operation of a dual platen press
US4240778A (en) * 1979-08-27 1980-12-23 Efco, Inc. System for providing for parallelism in fluid powered press or the like
US4490315A (en) * 1982-02-04 1984-12-25 Northern Telecom Limited Methods of moulding of plastics articles
US5198241A (en) * 1991-01-29 1993-03-30 Spex Industries, Inc. Apparatus for preparation of samples for spectrographic analysis
US5547360A (en) * 1994-03-17 1996-08-20 Tamagawa Machinery Co., Ltd. Powder molding press

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2645849A1 (de) * 1976-10-11 1978-04-13 Osterwalder Ag Hydraulisch angetriebene presse
DE2808091A1 (de) * 1978-02-24 1979-08-30 Moog Gmbh Einrichtung zum daempfen des schnittschlags bei hydraulischen pressen
DE2830779C2 (de) * 1978-07-13 1984-03-08 Eckhard 4512 Wallenhorst Schulz Hydraulische Doppeldruckpresse
DE3142126A1 (de) * 1981-10-23 1983-05-11 Dorst-Keramikmaschinen-Bau Otto Dorst U. Dipl.-Ing. Walter Schlegel, 8113 Kochel "presse zum herstellen masshaltiger presslinge aus pulverfoermigem material"
DE3829128A1 (de) * 1988-08-27 1990-03-08 Laeis Gmbh Verfahren zur herstellung von pressformteilen und vorrichtung zur durchfuehrung des verfahrens
DE4331017C2 (de) * 1993-09-13 1999-09-23 Langenstein & Schemann Gmbh Verfahren zum Steuern einer Presse für Steinformlinge

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742811A (en) * 1970-08-13 1973-07-03 Us Navy Apparatus for controlling the fabrication of electroexplosive devices
US4035118A (en) * 1973-08-27 1977-07-12 Macmillan Kenneth T Self-centering matrices for retreading molds
US3901635A (en) * 1974-02-08 1975-08-26 Wean United Inc Control system for briquetters
US4184827A (en) * 1975-12-16 1980-01-22 General Electric Company Apparatus for monitoring and controlling the operation of a dual platen press
US4199539A (en) * 1975-12-16 1980-04-22 General Electric Company Method for monitoring and controlling the operation of a dual platen press
US4081910A (en) * 1976-05-19 1978-04-04 Hammond H Jack Shut height gauge and method of using same
US4240778A (en) * 1979-08-27 1980-12-23 Efco, Inc. System for providing for parallelism in fluid powered press or the like
US4490315A (en) * 1982-02-04 1984-12-25 Northern Telecom Limited Methods of moulding of plastics articles
US5198241A (en) * 1991-01-29 1993-03-30 Spex Industries, Inc. Apparatus for preparation of samples for spectrographic analysis
US5346381A (en) * 1991-01-29 1994-09-13 Instruments Sa, Inc. Apparatus for preparation of samples for spectrographic analysis
US5547360A (en) * 1994-03-17 1996-08-20 Tamagawa Machinery Co., Ltd. Powder molding press

Also Published As

Publication number Publication date
DE1752005A1 (de) 1971-07-15
GB1210877A (en) 1970-11-04
FR1556871A (de) 1969-02-07
DE1752005C3 (de) 1975-02-13
DE1752005B2 (de) 1974-07-04
SE338241B (de) 1971-08-30

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