EP0152928B1 - Verfahren und Vorrichtung zum Verdichten von Giessereiformstoff - Google Patents

Verfahren und Vorrichtung zum Verdichten von Giessereiformstoff Download PDF

Info

Publication number
EP0152928B1
EP0152928B1 EP85101687A EP85101687A EP0152928B1 EP 0152928 B1 EP0152928 B1 EP 0152928B1 EP 85101687 A EP85101687 A EP 85101687A EP 85101687 A EP85101687 A EP 85101687A EP 0152928 B1 EP0152928 B1 EP 0152928B1
Authority
EP
European Patent Office
Prior art keywords
fact
accordance
press plate
pressure
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
Application number
EP85101687A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0152928A2 (de
EP0152928A3 (en
Inventor
Norbert Damm
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.)
BMD Badische Maschinenfabrik Durlach GmbH
Original Assignee
BMD Badische Maschinenfabrik Durlach GmbH
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 BMD Badische Maschinenfabrik Durlach GmbH filed Critical BMD Badische Maschinenfabrik Durlach GmbH
Publication of EP0152928A2 publication Critical patent/EP0152928A2/de
Publication of EP0152928A3 publication Critical patent/EP0152928A3/de
Application granted granted Critical
Publication of EP0152928B1 publication Critical patent/EP0152928B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/02—Compacting by pressing devices only
    • B22C15/08—Compacting by pressing devices only involving pneumatic or hydraulic mechanisms

Definitions

  • the invention relates to a method for compacting foundry molding material, in particular molding sand, by means of a pressing plate lying directly on the molding material surface, which is accelerated to a lifting speed of up to 20 m / s by means of driving force.
  • the invention further relates to devices for carrying out the method.
  • the causes should not only be the above-mentioned disadvantages, but also the fact that with the usual overall height of molded boxes and a correspondingly large compression stroke, highly explosive explosives with the corresponding energy content would have to be used, which naturally also entail safety-related risks. After all, the achievable mold hardness must be regarded as positive with this dynamic pressing.
  • the invention has for its object to further develop the latter method in such a way that a uniform and reproducible compression is achieved.
  • this object is achieved in that the press plate accelerates up to 50% of the total stroke time up to the maximum stroke speed in the start-up phase, moves with an almost constant stroke speed in the subsequent movement phase and up to a maximum of 30% of the stroke in the run-out phase Total stroke time is degressively delayed.
  • the method according to the invention initially results in a soft initial acceleration of the press plate and thus also of the molding material, as a result of which excessive compression in the region of the mold back is avoided.
  • the Compression continues after this start-up phase in the main phase, in which the maximum lifting speed is reached and maintained almost constant, and leads to an increasing compression of the molding material over the entire molding material height.
  • the advantage is achieved that the compression pressure persists for a long time due to the speed curve and is only gradually reduced in the run-down phase. This pressure adjustment leads to a uniform mold hardness over the entire height of the molding material.
  • the absolute value of the mold hardness leaves. determine themselves by setting the maximum lifting speed.
  • Another solution of the invention which can be used in connection with the aforementioned method, is that the lifting speed of the press plate is chosen inversely proportional to the height of the molding material.
  • the lifting speed is advantageously between 20 and 12 m / s for molds up to 200 mm high and between 12 and 7 m / s for molds with 200 to 400 mm high and between 7 and 2 m / s for molds larger than 400 mm. In this way, reproducible degrees of compaction depending on the height of the molding material or the height of the mold to be produced can be obtained.
  • the press plate is driven by means of a prestressed spring drive, preferably by means of a gas spring in the form of a closed, high-tensioned compressed gas volume.
  • the driving force generated by the compressed gas volume is therefore transmitted directly to the press plate and is not, as in the prior art of the generic type, first converted into the acceleration of a push piston, which is then braked on the press plate.
  • the compressed gas is advantageously recompressed after the expansion, so that the drive gas always remains in the drive system.
  • the explosion process eliminates the need for exhaust gas removal and ventilation.
  • the maximum lifting speed of the pressure plate is set by the level of the gas pressure and the gas pressure drop over time and thus the time profile of the lifting speed of the pressure plate is controlled by hydraulic back pressure.
  • the level of the gas pressure determines the maximum lifting speed and is set according to the height of the molding material and / or the desired compression. The rule to be followed is that the higher the desired compression and the lower the height of the molding material, the higher the gas pressure must be.
  • the drop in gas pressure over time which determines the course of the acceleration or deceleration of the press plate, can be controlled by means of the hydraulic counterpressure with the least expenditure on machinery and equipment.
  • another control option for the speed curve results from the fact that the compressed gas volume is closed off with one or more. spanned gas volumes, which are connected in the course of the pressure drop. In this way, for example, given a small volume of compressed gas, the maximum stroke speed can be maintained over a longer period of time or a longer stroke without the need for large pressure accumulators. Such a series connection of several gas volumes enables simple control by switching individual gas volumes on and off.
  • the press plate is decoupled from the driving force of the gas volume in the phase of the lifting movement and decelerated to its end position solely because of the resistance of the molding material to counteract its inertia.
  • the method according to the invention can also be implemented in that the press plate is driven electromagnetically, since fast accelerations and high speeds are also possible with such a drive.
  • magnetic fields of controllable intensity can be brought into effect along the stroke of the press plate.
  • the invention is based on a device which, in a conventional manner, consists of a model plate, a molding box containing the molding material with filling frame and a pressing plate arranged above it with a drive, under the effect of which the pressing plate is immersed in the filling frame with compression of the molding material .
  • a device which, in a conventional manner, consists of a model plate, a molding box containing the molding material with filling frame and a pressing plate arranged above it with a drive, under the effect of which the pressing plate is immersed in the filling frame with compression of the molding material .
  • Such known devices are used, for example, for static pressing with a hydraulic drive.
  • such a device is characterized in that a storage device with high-pressure gas is used as the drive. whose boundary is formed by a drive piston to which the press plate is connected, that the drive piston is on its opposite side under the action of a hydraulic counter-load, which corresponds to the controllable flow rate of a hydraulic medium from a hydraulic chamber Chend the desired course of the lifting speed of the press plate is degradable, and that the discharge cross-sections of the hydraulic chamber are designed so that the hydraulic medium can run at a speed of more than 10 m / s in order to achieve the maximum lifting speed of up to 20 m / s .
  • the working pressure of the compressed gas reservoir can be preset by changing the volume, so that the total stroke and the pressure height can be adapted to the height of the molding material.
  • the pressure curve over the entire stroke can also be influenced by the fact that the compressed gas store is connected to at least one switchable external compressed gas store.
  • the pressure plate is guided axially displaceably on the drive piston. This enables the pressure plate to be driven directly when the gas volume is released and, after relaxation has taken place, to be moved further on the basis of its kinetic energy in order to effect the residual compression in the run-down phase.
  • the press plate is profiled in accordance with the model contour.
  • it can have individual elevations in order to achieve uniform compression over the entire height of the molding material, regardless of the respective model height.
  • the mass of the press plate is preferably selected inversely proportional to the height of the molding material or the molding material mass.
  • the mass of molding material and press plate to be decelerated is also decisive. Due to the inverse proportionality of the mass, the proportionally higher plate mass acts instead of the lower molding material mass at a low molding material height and, together with the desired higher lifting speed at low molding material heights, leads to a comparatively higher compression impulse with a correspondingly high compression intensity.
  • the pressure plate mass and the molding material mass are in a ratio between 1: 1 and 1:10.
  • the lifting speed and the speed curve can also be influenced in a simple manner by selecting the pressure plate mass. With the same driving force, a shorter press-on phase with a higher lifting speed is achieved with a smaller press plate mass.
  • a further device suitable for carrying out the method is characterized according to the invention in that the drive consists of a plurality of electromagnetic coils arranged axially one behind the other and the press plate has a coil body immersed in it. The press plate can thus be accelerated in accordance with the desired speed profile.
  • the current intensity of each coil can be controllable in order to influence the height of the lifting speed and its course over time. This can also be achieved by switching the coils on and off separately.
  • the coil former is advantageously arranged in a free-flying manner within the coils and is held in the raised starting position by a centering and retention coil.
  • the diagram according to FIG. 2 provides information about the course of the speed of the press plate which occurs in the known and the method according to the invention.
  • the stroke speed peaks at the moment of the impact of the impact piston and thereafter decreases linearly over a larger area and decreases degressively in the run-down phase.
  • the speed increases up to to achieve the maximum lifting speed, which then remains approximately constant over a larger area, the main phase, in order to change relatively suddenly into a degressive deceleration in the phase-out phase.
  • the maximum lifting speed is adapted to the height of the molding material and the desired degree of compaction.
  • Figure 3 shows an embodiment of a device solution.
  • a model 2 sits on a plate 1 that can be raised and lowered, and a molding box 3 surrounding it, onto which a filling frame 4 is placed.
  • Molding box 3 and filling frame 4 are conventionally prior to compression with molding material, for.
  • a compression unit Arranged above this molding unit is a compression unit, generally designated 6, which essentially consists of a pressure cylinder 7 and a press plate 8.
  • the press plate 8 has a peripheral edge 8a drawn downwards and is guided by means of guide rods 9 in the stationary part 6a of the compression unit 6.
  • the press plate 8 is further guided at its center on a pin 10 by means of an extension 8b and axially movable on it to a limited extent, a collar 11 arranged at the end of the guide pin 10 serving as the limit stop and having the bottom 12 of a recess 12a in the press plate 8 cooperates.
  • the guide pin 10 sits on the piston rod 13 of a drive piston 15 which, like the piston rod 13, is provided with a cylindrical cavity 14.
  • the piston rod 13 and the piston 15 represent the lower limit of a cylinder space 16, which serves as a gas pressure accumulator.
  • the upper limit of the volume of the gas pressure accumulator 16 is formed by an actuating piston 17 which projects with an extension 18 into the cylindrical space 14 of the piston 15.
  • the actuating piston 17 in turn delimits a pressure chamber 19 which is acted upon hydraulically via an opening 20.
  • On the piston 17 also engages a shift rod 21 which passes through the upper cover of the pressure cylinder 7.
  • a hydraulic chamber 22 is delimited by the drive piston 15, the piston rod 13, the pressure cylinder 7 and the lower cylinder cover and can be acted upon by hydraulic oil via connections 23 which also serve as a drain.
  • the gas pressure accumulator 16 can be connected via connections 24 to one or more further gas pressure accumulators of constant volume, which can be used to track leakage air or as gas volumes that can be switched on and off to change the overall stroke.
  • the starting position before a compression stroke is shown in FIG.
  • the press plate 8 has previously been placed on the surface of the molding material filling 5 together with the molding box 3 and the filling frame 4 by lifting the model plate 1 into its upper position, being on the guide pin 10 until the upper end face 25 stops centric approach 8b on a stop disc 26 of the piston rod 13 has been performed.
  • the drive piston 15 is under a gas prestress in the cylinder space 16 and a hydraulic back pressure in the hydraulic space 22.
  • the cross section of the outflow 23 is designed so that the outflow speed is in any case above 10 m / s, so that piston speeds between 2 and 20 m / s can be generated.
  • the temporal degradation of the gas pressure in the gas pressure accumulator 16, the effective area of the drive piston 15, the piston mass, the mass of the pressure plate 8, the hydraulic drainage capacity and the mold box area and the height of the compression stroke determine the compression speed and thus the compression result.
  • the piston rod 13 Before reaching its end position, the drive piston 15 is braked.
  • the piston rod 13 has a conical extension 13a at its upper end.
  • a damping ring 7a is inserted into the lower end of the cylinder 7, through whose opening 7b the piston rod 13 engages.
  • the cross section of the annular space present between the piston rod 13 and the wall of the opening 7b is appreciably larger than the cross section of the outlets 23.
  • the limited displaceability of the press plate 8 on the guide pin 10 leads to a free stroke, which is indicated by 27 in FIG. In this way, fluctuating properties of the molding material and the associated different compression strokes can be automatically compensated. If the working piston 15 has reached its end position, the pressure plate 8 will continue to move due to its inertia up to the end position, which is determined by the fluidity of the molding material particles still present, and will also produce an additional compression effect on the back of the mold.
  • the pressure plate 8 Since air can be trapped within the molding column and below the pressure plate 8 at high compression speeds, the pressure plate 8 is to avoid shape errors with slots, holes or nozzles 28 provided.
  • the volume of the gas pressure accumulator 16 which also includes the volume of the cylindrical cavity 14, which is provided for reasons of weight saving, can be adjusted via the actuating piston 17. This allows the output pressure and thus the initial acceleration of the working piston to be varied. The final pressure remains constant regardless of the arrangement of the control piston 17 with a constant piston stroke. However, as already indicated, the time course of the acceleration can be varied by connecting external gas stores via the connections 24. These additional gas accumulators are also compressed back to their initial pressure when the working piston 15 is reset by means of the hydraulic medium.
  • FIG. 4 an embodiment is shown, the adjustment of the compression stroke, for. B. to adapt to different model geometries.
  • a damping sleeve 29 is arranged, which is offset from the pressure cylinder 7 by an annular space 30 on part of its outer surface.
  • the damping sleeve 29 is also provided with a plurality of openings 31 which establish the connection between the hydraulic space and the connections 23.
  • the damping sleeve 29 can be axially raised and adjusted via a hydraulic system acting on its underside with a connection 32, while the lowering takes place in the hydraulic chamber 22 by the hydraulic fluid.
  • the stroke length of the damping sleeve 29 should be approximately 20 to 30% of the compression stroke.
  • the molding material is first pre-accelerated below the additional pressure plate mass 35 until finally the remaining lower surface of the pressure plate runs onto the molding material back. The entire molding material mass is then accelerated further.
  • the pressure plate 8 and the additional pressure plate mass 35 will each continue to run into their respective end positions independently of one another and depending on the compression of the molding material that is achieved in some areas.
  • Figure 6 shows a variant which is particularly suitable for larger molded boxes.
  • two compression units 6, each with a press plate 8 are arranged next to one another on a common carrier 39, each press plate 8 covering approximately half the cross section of the molding box 3 or the filling frame 4.
  • the compression stroke of the two compression units 6 can be triggered together, but does not require an exact synchronization movement.
  • the switching elements that control the outflow of the hydraulic medium from the hydraulic chamber 22 of the pressure cylinder 7 are expediently arranged in parallel and a pressure compensation line is provided in front of the switching elements.
  • the variant according to FIG. 6 can also be modified in such a way that the upper and lower boxes of a complete box shape can be produced in a single work cycle.
  • FIG. 5 shows an advantageous exemplary embodiment of the hydraulic control.
  • the connections 23 are in a hydraulic high-pressure circuit, the source of which, for. B. a hydraulic pump, designated 41. It is fed from a tank 46. From the high-pressure source 41, the pressure medium passes through a control slide 42 and a check valve 43 into branch lines 44, which guide the pressure medium to the two connections 23 of the hydraulic chamber 22.
  • the branch lines 44 are connected via a controllable check valve 45 to an outlet tank 47, the outlet 48 of which opens into the tank 46 and which also has a vent 50.
  • the check valve 45 is connected to the control slide 42 via a control line 49 and can therefore be acted upon by the hydraulic pump 41. If necessary, the hydraulic chamber 22 can also be connected to the branch lines 44 via a line 51 and a throttle 52 for fine adjustment.
  • hydraulic chamber 22 In position B of control spool 42, hydraulic chamber 22 is acted upon by hydraulic pump 41, so that working piston 15 brings the gas volume in accumulator 16 to the desired final pressure.
  • the controllable check valve 45 is in the closed position.
  • the press plate 8 is by tracking the model plate 1 with mold box 3 and Filling frame 4 has been moved to its upper starting position.
  • the hydraulic chamber 22 is closed off from the hydraulic pump 41 via the check valve 43, while at the same time the pump opens the check valve 45 via the control line 49.
  • the hydraulic fluid can suddenly flow into the drain tank 47 via the connections 23, the branch lines 44 and the open check valve 45, the volume of which is large enough to hold the entire hydraulic quantity of the system and to reduce the pressure suddenly.
  • the working piston 15 and the pressure plate 8 move downward at the desired speed in order to compress the molding material filling 5.
  • FIG. 7 finally shows an embodiment of a compression unit 6 with an inductive drive.
  • a bobbin 54 with a plurality of coils 55, 56, 57 and 58 which are arranged axially one above the other, separately excitable and controllable is arranged in a machine frame 53. Furthermore, a stabilizing and holding coil 59 is present above the coil package 55 to 58.
  • the press plate 8 is fastened by means of rods 60 to a coil core 61 which is penetrated by the piston rod 62 with a terminal driver 63 of a log cylinder 64.
  • the cylindrical coils 55 to 59 generate a homogeneous, directed electromagnetic force field which automatically aligns the coil core 41 in the rest position, as well as during the movement.
  • the compression stroke can be changed in stages by the number of connected coils 55 to 58.
  • the course of acceleration is influenced by the field strength acting on the coil core 61 and, for a given dimension, depends on the current strength within the saturation range of the material of the coil core.
  • the compression result can thus be varied not only by varying the compression stroke, but also by changing the current strength of the coils.
  • the pressing plate 8 After compression has taken place, the pressing plate 8 is brought back into its starting position by means of the log cylinder 64 and fixed by activating the retention coil 59. Before each compression stroke, the piston rod 62 is extended to the position shown in FIG. 7.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)
  • Press Drives And Press Lines (AREA)
  • Control Of Presses (AREA)
EP85101687A 1984-02-23 1985-02-15 Verfahren und Vorrichtung zum Verdichten von Giessereiformstoff Expired EP0152928B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3406466 1984-02-23
DE3406466A DE3406466A1 (de) 1984-02-23 1984-02-23 Verfahren und vorrichtung zum verdichten von giessereiformstoff

Publications (3)

Publication Number Publication Date
EP0152928A2 EP0152928A2 (de) 1985-08-28
EP0152928A3 EP0152928A3 (en) 1986-06-04
EP0152928B1 true EP0152928B1 (de) 1988-01-20

Family

ID=6228536

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85101687A Expired EP0152928B1 (de) 1984-02-23 1985-02-15 Verfahren und Vorrichtung zum Verdichten von Giessereiformstoff

Country Status (5)

Country Link
US (1) US4617978A (enrdf_load_stackoverflow)
EP (1) EP0152928B1 (enrdf_load_stackoverflow)
JP (1) JPH078411B2 (enrdf_load_stackoverflow)
DD (1) DD235197A5 (enrdf_load_stackoverflow)
DE (2) DE3406466A1 (enrdf_load_stackoverflow)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8628132D0 (en) * 1986-11-25 1986-12-31 Doyle Ltd C F Compacting moulding mixture
CH672270A5 (enrdf_load_stackoverflow) * 1986-12-17 1989-11-15 Fischer Ag Georg
DE3740185A1 (de) * 1987-06-13 1989-06-08 Badische Maschf Gmbh Verfahren und vorrichtung zum verdichten von formstoff in giesserei-formmaschinen
DE3719846A1 (de) * 1987-06-13 1988-12-22 Badische Maschf Gmbh Verfahren und vorrichtung zum verdichten von formstoff in giesserei-formmaschinen
US5070928A (en) * 1990-02-28 1991-12-10 General Motors Corporation Forming press with quick-change tool-to-bolster locking mechanism
CH686412A5 (de) * 1992-03-10 1996-03-29 Fischer Georg Giessereianlagen Verfahren zum Verdichten von Formsand fuer Giessformen.
US5535809A (en) * 1993-11-24 1996-07-16 Grand Haven Brass Foundry Method and apparatus for packing a granular material for foundry use
WO2001070432A1 (en) * 2000-03-20 2001-09-27 Georg Fischer Disa A/S Method and apparatus for producing two-part moulds

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3233291A (en) * 1960-09-26 1966-02-08 Osborn Mfg Co Explosive force molding machine and method
DE7602966U1 (de) * 1976-02-03 1976-06-24 Badische Maschinenfabrik Gmbh, 7500 Karlsruhe Giesserei-formmaschine fuer kastenformen
DE2844464C2 (de) * 1978-10-12 1983-03-24 Bühler, Eugen, Dipl.-Ing., 8871 Burtenbach Verfahren und Vorrichtung zum Verdichten von Gießformen
JPS55120450A (en) * 1979-03-08 1980-09-16 Sintokogio Ltd Mold molding apparatus
DE3002702C2 (de) * 1980-01-25 1983-09-22 Alfelder Maschinen- und Modell-Fabrik Künkel, Wagner & Co KG, 3220 Alfeld Vorrichtung zum Zuführen des Formsandes in den in einer Sandformmaschine in Bereitschaft gehaltenen Formkasten

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Litejnoe Proizvodstro in Deutsch" Jg. 1973 H3, S. 6-9 *

Also Published As

Publication number Publication date
DE3406466A1 (de) 1985-08-29
EP0152928A2 (de) 1985-08-28
JPS60255237A (ja) 1985-12-16
DD235197A5 (de) 1986-04-30
DE3406466C2 (enrdf_load_stackoverflow) 1989-02-02
US4617978A (en) 1986-10-21
DE3561444D1 (en) 1988-02-25
EP0152928A3 (en) 1986-06-04
JPH078411B2 (ja) 1995-02-01

Similar Documents

Publication Publication Date Title
EP0152928B1 (de) Verfahren und Vorrichtung zum Verdichten von Giessereiformstoff
DE68909861T2 (de) Hydraulisches Schlagwerkzeug.
EP0170765A1 (de) Vorrichtung zum Verdichten von Giesserei-Formstoff
EP0127069B1 (de) Vorrichtung zum Verdichten von Giessereiformsand im Gasdruckverfahren
EP0131723B1 (de) Vorrichtung zum Verdichten von Giesserei-Formstoff mittels Druckgas
DE2165929B2 (de) Einrichtung zum beschleunigten aufbau und zur regulierung des nachdruckes an druckgiessmaschinen, insbesondere kaltkammer-druckgiessmaschinen
EP0139119B2 (de) Verfahren und Vorrichtung zum Verdichten von kornförmigen Formstoffen z.B. Giessereiformsand
EP0203322B1 (de) Vorrichtung zum Verdichten von Giesserei-formstoff mittels Druckgas
EP0152573B1 (de) Vorrichtung zum Verdichten von Giesserei-Formstoff mittels Druckgas
EP1053801B1 (de) Hydraulische Schliessvorrichtung zum Querfliesspressen von Werkstücken
EP0417753A2 (de) Mechanische oder hydraulische Presse mit Zieheinrichtung oder Ziehstufe einer Stufenpresse
DE3532190C2 (enrdf_load_stackoverflow)
DE2701693C2 (de) Formmaschine zum Herstellen von Gießformen
DE3123498C1 (de) Vorrichtung zum beschleunigten Aufbau und zur Regulierung des Nachdruckes an Druckgiessmaschinen
DE2755495C2 (enrdf_load_stackoverflow)
DE4028920A1 (de) Mechanische oder hydraulische presse mit zieheinrichtung oder ziehstufe einer stufenpresse
DE1155883B (de) Verfahren zur Herstellung von Kernen und Formen fuer Giessereizwecke
AT268010B (de) Auswerfereinrichtung für Schlagverformungsmaschinen
DD210530A3 (de) Vorrichtung zur erzeugung von druckimpulsen
DE2036232A1 (de) Giesserei-Formmaschine
DE3613202A1 (de) Einrichtung zur herstellung von keramischen formlingen stichwort: gefederter schiesskopf
DE3632925A1 (de) Verfahren und vorrichtung zur daempfung der am ende der formfuellphase auftretenden druckspitze bei druckgiessmaschinen
DD286946A7 (de) Verfahren zur pneumatischen erzeugung von stoessen
EP0768127A2 (de) Ziehvorrichtung für eine Presse
DE3500488A1 (de) Vorrichtung zum herstellen von giessformen

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): CH DE FR GB LI

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): CH DE FR GB LI

17P Request for examination filed

Effective date: 19860524

17Q First examination report despatched

Effective date: 19861016

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB LI

REF Corresponds to:

Ref document number: 3561444

Country of ref document: DE

Date of ref document: 19880225

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19980127

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19980205

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19980225

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990215

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19990316

Year of fee payment: 15

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF THE APPLICANT RENOUNCES

Effective date: 19990506

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19990215

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19991029

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000229

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000229

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL