EP0019597A2 - Sicherungsvorrichtung für hydraulische Systeme - Google Patents

Sicherungsvorrichtung für hydraulische Systeme Download PDF

Info

Publication number
EP0019597A2
EP0019597A2 EP80830027A EP80830027A EP0019597A2 EP 0019597 A2 EP0019597 A2 EP 0019597A2 EP 80830027 A EP80830027 A EP 80830027A EP 80830027 A EP80830027 A EP 80830027A EP 0019597 A2 EP0019597 A2 EP 0019597A2
Authority
EP
European Patent Office
Prior art keywords
valve
section
safety device
pressure
output
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.)
Withdrawn
Application number
EP80830027A
Other languages
English (en)
French (fr)
Other versions
EP0019597A3 (de
Inventor
Giuseppe Cinotto
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.)
CHS GIUSEPPE CINOTTO HYDRAULIC SYSTEM SpA
Original Assignee
CHS GIUSEPPE CINOTTO HYDRAULIC SYSTEM SpA
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 CHS GIUSEPPE CINOTTO HYDRAULIC SYSTEM SpA filed Critical CHS GIUSEPPE CINOTTO HYDRAULIC SYSTEM SpA
Publication of EP0019597A2 publication Critical patent/EP0019597A2/de
Publication of EP0019597A3 publication Critical patent/EP0019597A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices
    • F15B13/015—Locking-valves or other detent i.e. load-holding devices using an enclosed pilot flow valve

Definitions

  • the present invention relates to a safety device for hydraulic circuits comprising a source of fluid under pressure, a double-acting hydraulic actuator having a cylinder and a piston dividing the internal volume of the actuator cylinder into first and second working chambers with the piston rod extending through the second working chamber, a distributor arranged to receive fluid under pressure from said source, first and second fluid lines intercommunicating said distributor with said first and second working chambers resDectively, and an hydraulic servo-control arranged to control said distributor by the application of a control pressure thereto.
  • the invention relates to a safety device for use with a double-acting actuator controlling the lifting arm of an excavator, power-lift or similar machine, the device being arranged to prevent the uncontrolled lowering of a load carried by the lifting arm of the.machine in the event of the accidental rupture of the fluid supply line which supplies fluid to the actuator during raising of the load.
  • Safety devices for preventing such uncontrolled operation of an actuator are known but traditionally employ two pressure take-offs, one'from each of the two fluid lines supplying the actuator. These known devices operate by monitoring the pressure difference between the two fluid lines.
  • the object of the present invention is to provide a safety device which is particularly reliable, and has a greater operating safety and is more convenient to use than known safety devices.
  • the present invention provides a safety device for hydraulic circuits, particularly for excavators, power-lifts or similar machines, characterised in that it comprises a valve unit placed in said first fluid line and having an automatic controlling section and a working valve section controlled by the controlling section: the controlling section comprising a body having an input connected to the said hydraulic servo-control and-an output connected to the working section, and a valve body slidable mounted in said body and displaceable between an open position in which said input and output are placed in communication with each other, and a closed position in which communication between said input and output is prevented; the working section comprising a body connected to the output of the controlling section and having an input connected to said first fluid line and an output connected to said hydraulic actuator, said input and output being also connected to the body of the controlling section; a non-return valve being placed within the body of the working section, said non-return valve being arranged for connection between said input and output of the work ing section, when the flow of fluid in the working section is directed from
  • the valve body of the controlling section of the safety device is preferably formed with a first surface arranged to be subjected to the input pressure of the working section and with a second surface arranged to be subjected to the output pressure of the working section, the valve body being, in addition, subjected to the action of adjustable bias means tending to maintain the said valve body in its open position; the sum of the forces acting on the said valve body being such that in the presence of normal working pressures the valve body is in its open position, whilst in the absence of the input pressure in said working section the valve body is displaced by the output pressure of the working section, against the action of the said adjustable bias means, in its closed position.
  • the hydraulic circuit shown in Figure 1 is arranged to control the movement of an arm 10 which, for example, forms part of a power-lift not illustrated.
  • the hydraulic circuit comprises a pump 12 which supplies fluid under pressure to a three-position hydraulic distributor 14 of a type known per se, controlled by means of a manually operable servo control 16, also of known type.
  • the hydraulic distributor 14 is connected by first and second lines 20 and 22 to the cylinder of a double-acting hydraulic actuator 18 the piston rod of which is pivoted to the arm 10.
  • the piston of the actuator 18 divides the internal volume of the actuator cylinder into first and second working chambers with the piston rod extending through the second working chamber.
  • the lines 20 and 22 communicate with the first and second working chambers respectively.
  • the safety device 24 embodying the invention is disposed in the first line 20 and is provided with means (not shown) enabling its secural to the cylinder of the actuator 18.
  • the safety device 24 is functionally represented by the diagram of Figure 2 and is arranged to allow uninhibited operation of the actuator 1 8 in the presence of normal operating conditions of the hydraulic circuit while preventing sudden exit of fluid from the first working chamber of the actuator cylinder (and thus sudden lowering of the arm 10) should the line 20 become ruptured.
  • the safety device 24 is constituted by a unit comprising a working valve section 26 (see Figure 3), and a controlling section 28( Figure 4).
  • the working section 26 includes a cylinder 30 having an input duct 32 connected to the first-line 20, and an output duct 34 which lies offset with respect to the duct 32, and communicates with the first working chamber of the hydraulic actuator 18.
  • a selectively-operable non-return valve 36 is disposed within the cylinder 30 and comprises a valve body 38 in the form of a cylindrical sleeve the axis of which is directed perpendicularly to the ducts 32 and 34.
  • One end opening of the sleeve 38 communicates with the duct 32 and can be closed off by the cooperation of a spherical valve closure member 42 slidably mounted in the interior of the sleeve 38 with a valve seat formed internally around the said one end opening.
  • the sleeve 38 At its opposite end the sleeve 38 has an end plate 43 which faces a plate 54 of the cylinder 30.
  • a helical spring 51 reacts between the plates 43 and 54.
  • the interior of the sleeve 38 communicates with the duct 34 through a circular array of calibrated radial holes 44 formed in the cylindrical wall of the sleeve 38 and, in addition, through at least one further calibrated radial hole 46 axially spaced from the holes 44.
  • An element 48 in the form of a cup is slidably mounted in the interior of the body 38 and sealingly engages the cylindrical wall of the sleeve 38.
  • the bottom of the cup element 48 bears against the spherical valve closure member 42 and is provided with inclined discharge holes 50.
  • the cup element 48 is urged towards the valve closure member 42 by the action of an helical spring 52 reacting against the inner face of the end plate 43 of the sleeve 38.
  • the spring 52 therefore tends to maintain the valve closure member 42 against the valve seat 40, thereby closing the non-return valve 36 and preventing communication between the ducts 32 and 34.
  • the valve closure member. 42 also serves to close off the holes 44 while leaving open the hole 46.
  • the non-return valve 36 is associated with a control device 56 controlled by the controlling section 26.
  • the control device 56 comprises a shaft 58 slidably mounted in the cylinder 30 coaxially with the sleeve 38.
  • One end of the shaft 58 bears against the valve closure member 42 on the side thereof opposite the cup element 48.
  • the other end of the shaft 58 has a hollow portion 60 which lies in a cavity 62 of the cylinder 30 and bears against the bottom of a cup-shaped body 64 slidably mounted in the cavity 62.
  • the body 64 is urged in a direction away from the shaft 58 by a helical spring 67.
  • the duct 66 is formed in a threaded plug which is engaged in the cylinder 30 and serves to close off the cavity 62.
  • This plug is formed with a cylindrical cavity 72 which opens coaxially into the cavity 62.
  • An auxiliary piston 70 is slidably mounted in the cavity 72 and sealingly engages the walls of the cavity 72. One end of the auxiliary piston 70 projects from the cavity 72 into the cavity 62 where it bears against the bottom of the cup-shaped body 64.
  • the input duct 32 and the output duct 34 respectively communicate via a duct 74 and a duct 76 formed in the cylinder 30, with an input 78 and an input 80 of the controlling section 28.
  • the duct 76 communicates via a duct 82 with the cavity 72 containing the auxiliary piston 70.
  • the output duct 34 also communicates with a fluid- collection reservoir 84 (see Figures 1 and 2) by means of a pair of ducts 86, 88 in which there are respectively disposed a manually operable bypass valve 90 and an anti-surge valve 92 of type known per se.
  • the controlling section 28 of the safety device 24 (see Figure 4) comprises a cylinder 94 formed with an input duct 96 which communicates with the output of the servo control 16.
  • the duct 96 is also selectively connectable, by means of a slide valve or spool valve 98, with the output 68 which, as previously mentioned, is connected to the duct 66 of the working section 26.
  • the valve 98 is constituted by a cylindrical body sealingly slidable in a cavity 100 formed in the cylinder 94 and into which opens the input duct.96'. This cylindrical body has a cylindrical head end portion 102, a central portion 104 of reduced diameter, and a hollow end portion 106.
  • the interior of the hollow end portion 106 communicates with the cavity 100 via an axial passage 108 formed in the central portion 104 and a series of radial holes 110 provided in the lateral wall of the valve body in the zone intermediate the cylindrical head portion 102 and the central portion 104.
  • the cavity 1 00 is formed with an annular groove 101 which communicates with the collection reservoir 84 through a duct 112 formed in the cylinder 94.
  • Axial displacement of the body of the valve 98 provides for the selective connection of the output duct 68 to the input duct 96 or to the duct 112 this axial displacement being brought about in a manner to be described hereinafter.
  • the hollow end portion 106 of the slide valve 98 is guided in a slidable manner between the walls of the cavity 100 and the enlarged head 114 of a shaft 116.
  • the end of the shaft 116 remote from the head 114 is threadedly engaged in a block 118 which is located in a flanged bush 120 mounted in the cylinder 98.
  • the shaft 116 carries a stack of dished plate springs 122 which react between the block 118 and a washer 124 located in the cavity 100 and bearing against the end of the hollow end portion 106 of the valve 98.
  • the block 118 On its side away from the springs 122, the block 118 is engaged by an adjustment screw 126 accessible from the exterior of the cylinder 94.
  • the interior of the flanged bush 120 communicates via a duct 128 with the input 78 which, as previously mentioned, communicates with the input duct 32 of the working section 26.. A.
  • a piston 130 is slidably mounted in a seal-tight manner inside the cavity 132 of a cylindrical bush 134 which is mounted in the cylinder 94 coaxially with the cavity 100.
  • the piston 130 bears against the end face of the valve end portion 102.
  • the cavity 132 communicates, through an axial passage 136;with a duct 140 connected to the input 80 which, as previously mentioned, communicates with the output duct 34 of the working section 26.
  • a needle valve 138 controls fluid flow through the passage 136.
  • a piston 142 bears against one end of the needle valve 138 to control its operation.
  • the piston 142 is slidably mounted in a seal-tight manner in a cavity 144 of an end cap 145 of the cylinder 94.
  • the piston 142 is provided with a stem 146 which mounts a stack of dished plate springs 148 serving to urge the piston 142 into engagement with the needle valve 138.
  • the portion of the cavity 144 lying on the opposite side of the piston 142 to the stem 146 communicates with the input duct 96 through a duct 150 formed in the cylinder 94.
  • the operator by manually acting on the servo control 16, selectively sets the state of the distributor 14 such as to cause the delivery of pressurised fluid from the pump 12 either to the first line 20 to bring about a raising of the arm 10 , or to the second line 22 to cause lowering of the arm 10.
  • a change in the selected state of the distributor is initiated by the appropriate application to the distributor 16 of a control fluid pressure P of a value of seven bars by the servo control 16 (in contrast, the pressure of fluid delivered by the pump 12 can be as much as 350 bars).
  • the safety device 24 In the presence of normal operating conditions in the hydraulic circuit, the safety device 24 is arranged to allow the uninhibited flow of fluid therethrough; however, should abnormal conditions arise, such as rupture of the line 20, which could lead to uncontrolled lowering of the arm 10, the safety device 24 effectively operates to prevent a sudden exit of fluid from the cylinder of the actuator 18.
  • the non-return valve 36 of the working section 26 is operatively inserted in the line 20 except when the distributor 14 is set for' lowering of the arm 10 and the controlling section 28 simultaneously detects the presence of normal operating conditions of the hydraulic circuit; in these latter conditions the non-return valve 36 is rendered inoperative by the control device 56.
  • Fluid from the line 20 enters the input duct 32 of the safety device 24 at an input pressure P d and causes the axial displacement of the sleeve 38 against the action of the spring 51.
  • the non-return valve 36 is opened to allow fluid to pass through the output duct 34 (at pressure P ) and into the interior of the hydraulic actuator 18.
  • removal of the input pressure P d (for example, due to the accidental rupture of the line 20) will result in the spring 52 closing the non-return valve 36 and thereby preventing uncontrolled lowering of the arm 10.
  • the provision of the anti-surge valve 92 allows the absorption of the pressure peaks occurring upon rupture of the line 20, whilst the by-pass valve 90 allows a subsequent slow and gradual manual lowering of the arm 10 to be achieved.
  • the controlling section 28 of the safety valve 24 acts to supply or cut off the control fluid pressure P s to the working section 26 in dependence on whether normal or abnormal operating conditions are present (the latter conditions corresponding, for example, to rupture of the line 20 ). If the control pressure signal P is fed to the working section 26, the non-return valve 36 is rendered inoperative and is opened to allow the passage of fluid through the holes 44 and the consequent lowering of the arm 10. If, on the other hand, the pressure signal P s is not supplied to the working section 26, the non-return valve 36 is allowed to close to prevent the lowering of the arm 10.
  • the supply of the control pressure P s to the working section 26 depends on the position of the valve 98 which is determined by the relative magnitudes of the various pressure and mechanical forces acting on the valve.
  • the equation of equilibrium of the valve 98 is as follows: in which X m is the force exerted by the spring 122, A is the surface area of the valve 98 subject to the pressure P d , B is the surface area of the head 114 of the shaft 116 subject to the pressure P s , and C is the surface area of the piston 130 subject to the pressure P .
  • valve 98 takes up a position in which it interrupts communication between the input duct 96 and the output 68 but establishes communication between the output 68 and the duct 112 connected to the reservoir 84.
  • the control pressure P s is no longer fed to the control device 56 of the working section 26 and as a consequence movement of the shaft 58 to the left as viewed in Figure 3 becomes possible so as to allow closure of the non-return valve 36.
  • the following condition of unbalance exists in the working section 26: where the term R represents the passive resistance of the working section 26.
  • the non-return valve 36 will therefore move to its closed position to prevent lowering of the arm 10.
  • the pressure P acts on the area F of the closure member 42 through the hole 46.
  • the values of the parameters X m (adjustable) and C must be chosen in accordance with the previously indicated equation of equilibrium for the valve 98, assuming for P a range of values lying between 50 and 350 bars with a corresponding range of values for P lying between 4.5 and 7 bars.
  • Variations in the pressure force P . B is achieved by varying the fluid flow between the ducts 96 and 112 in dependence on the position of the valve body 98, the valve position being in turn dependent on the difference between the pressures P c and P d .
  • the equation of equilibrium of the needle valve 138 is as follows: where X b is the force exerted by the springs 1 4 8, G is the area of the end of the needle valve 138 subject to the pressure P , and I is the surface area of the needle valve 138 subject to the pressure P c .
  • the needle valve 1.38 upon the distributor 14 being set to lower the arm 10 the needle valve 1.38 must be arranged to open after the opening of the non-return valve 36 under the action of the control pressure P s on the control device 56; in this manner, provided the line 20 is not ruptured, pressure will be re-established in the duct 32 to ensure proper operation of the controlling section 28.
  • FIG. 5 A modified form of the working section 26 of the safety device 24 is shown in Figure 5.
  • the working section 26 shown in Figure 5 differs from that illustrated in Figure 3 only in that the valve closure member of the non-return valve 36 is constituted by a cup-shaped body 1.60 rather than by a spherical member 42.
  • the cup-shaped body 160 is slidably mounted in the interior of the sleeve 38 and is formed with a frusto-conical end 162 arranged to cooperate with the valve seat 40.
  • the spring 52 reacts directly against the cup-shaped body 160 in such a way as to urge the frusto-conical end 162 towards the valve seat 40.
  • the interior of the cup-shaped body 160 communicates with the interior of the sleeve 38 by means of a series of calibrated radial holes 164 formed in the lateral wall of the body 160.
  • the radial holes 164 serve the same function as the hole 46 described with reference to Figure 3.
  • the operation of the Figure 5 form of the working section 26 is the same as for the Figure 3 form.
  • the described safety device is particularly suitable for use with double-acting hydraulic actuators incorporated in power-lifts, excavators and the like.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Lifting Devices For Agricultural Implements (AREA)
EP80830027A 1979-05-18 1980-05-06 Sicherungsvorrichtung für hydraulische Systeme Withdrawn EP0019597A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT68061/79A IT1118648B (it) 1979-05-18 1979-05-18 Dispositivo di sicurezza per circuiti idraulici particolarmente di scavatrici sollevatori e simili
IT6806179 1979-05-18

Publications (2)

Publication Number Publication Date
EP0019597A2 true EP0019597A2 (de) 1980-11-26
EP0019597A3 EP0019597A3 (de) 1981-04-22

Family

ID=11307558

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80830027A Withdrawn EP0019597A3 (de) 1979-05-18 1980-05-06 Sicherungsvorrichtung für hydraulische Systeme

Country Status (2)

Country Link
EP (1) EP0019597A3 (de)
IT (1) IT1118648B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3305282A1 (de) * 1982-02-18 1983-08-25 Atlas Copco AB, Nacka Lasthalteventil oder overcenterventil fuer hydraulische anlagen
EP0331076A1 (de) * 1988-03-03 1989-09-06 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Hydraulische Schaltung für Zylinder
EP0466582A1 (de) * 1990-07-13 1992-01-15 Kabushiki Kaisha Kosmek Hydraulische Schaltung zum Heben und Senken und Ventilblock für diese Schaltung
WO2005021978A1 (de) * 2003-08-27 2005-03-10 Bucher Hydraulics Ag Hydraulisch gesteuertes ventil mit mindestens einem hydraulischen antrieb

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3164171A (en) * 1961-01-30 1965-01-05 Clark Equipment Co Directional control valve
US3500721A (en) * 1968-07-23 1970-03-17 Eaton Yale & Towne Hydraulic control for two hydraulic motors
DE2209506A1 (de) * 1972-02-29 1974-01-24 Montan Hydraulik Gmbh & Co Kg Einrichtung zum steuern von hydroantrieben unter last
FR2231910A1 (en) * 1973-06-04 1974-12-27 Griffet Ets M Control valve for hydraulic jack of crane jib - has piston operated by low pressure oil to control main oil flow
DE2424973A1 (de) * 1974-05-22 1975-12-04 Montan Hydraulik Gmbh & Co Kg Einrichtung zum steuern von hydroantrieben
FR2312676A1 (fr) * 1975-05-27 1976-12-24 Caterpillar Tractor Co Systeme d'elevation de charge hydraulique

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3164171A (en) * 1961-01-30 1965-01-05 Clark Equipment Co Directional control valve
US3500721A (en) * 1968-07-23 1970-03-17 Eaton Yale & Towne Hydraulic control for two hydraulic motors
DE2209506A1 (de) * 1972-02-29 1974-01-24 Montan Hydraulik Gmbh & Co Kg Einrichtung zum steuern von hydroantrieben unter last
FR2231910A1 (en) * 1973-06-04 1974-12-27 Griffet Ets M Control valve for hydraulic jack of crane jib - has piston operated by low pressure oil to control main oil flow
DE2424973A1 (de) * 1974-05-22 1975-12-04 Montan Hydraulik Gmbh & Co Kg Einrichtung zum steuern von hydroantrieben
FR2312676A1 (fr) * 1975-05-27 1976-12-24 Caterpillar Tractor Co Systeme d'elevation de charge hydraulique
US4000683A (en) * 1975-05-27 1977-01-04 Caterpillar Tractor Co. Hydraulic load lifting system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3305282A1 (de) * 1982-02-18 1983-08-25 Atlas Copco AB, Nacka Lasthalteventil oder overcenterventil fuer hydraulische anlagen
EP0331076A1 (de) * 1988-03-03 1989-09-06 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Hydraulische Schaltung für Zylinder
US4955283A (en) * 1988-03-03 1990-09-11 Kabushiki Kaisha Kobe Seiko Sho Hydraulic circuit for cylinder
EP0466582A1 (de) * 1990-07-13 1992-01-15 Kabushiki Kaisha Kosmek Hydraulische Schaltung zum Heben und Senken und Ventilblock für diese Schaltung
WO2005021978A1 (de) * 2003-08-27 2005-03-10 Bucher Hydraulics Ag Hydraulisch gesteuertes ventil mit mindestens einem hydraulischen antrieb

Also Published As

Publication number Publication date
IT1118648B (it) 1986-03-03
IT7968061A0 (it) 1979-05-18
EP0019597A3 (de) 1981-04-22

Similar Documents

Publication Publication Date Title
US5381823A (en) Hydraulic pressure control valve
EP1701074B1 (de) Druckbegrezungsventil mit Entlüftungsdämpfung
JP3298623B2 (ja) 非シャトル圧力補償器付液圧制御バルブ装置
US4727792A (en) Hydraulic holding valve
CA2492414C (en) Control system for a load handling apparatus
EP0559903B1 (de) Ventilvorrichtung
JPS6145103B2 (de)
KR20010032948A (ko) 이동 작업 기계용, 특히 종방향 진동의 감쇠를 위한 휠로우더용 유압 제어 장치
US4485724A (en) Hydraulic control apparatus
US4546786A (en) Flow control valve
US4018136A (en) Hydraulic apparatus for controlling movement of a member under loading
US5750950A (en) Hydraulic drive device for circuit breaker and circuit breaker using the same
US4091832A (en) Valve
JPH0231085A (ja) 油圧容器用の安全弁とそれを備える油圧回路
EP0019597A2 (de) Sicherungsvorrichtung für hydraulische Systeme
US3943825A (en) Hydraulic control system for load supporting hydraulic motors
CA1201039A (en) Control of fluid pressure circuits
US4133206A (en) Thrusting force detecting device of a rotary machining tool
US4344285A (en) Signal bleed-down valve
US4084604A (en) Pressure responsive distributing valve
US4286502A (en) Hydraulic load lifting system with automatic blocking valve
GB2047316A (en) Improvements in hydraulic control apparatus for controlling the operation of mine roof support props
US4862919A (en) Hydraulic control system for a multi-position valve
US2988060A (en) Automatic speed control safety valve for hydraulic elevators
US4445666A (en) Hydraulic jack device

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): AT BE CH DE FR GB IT LU NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19820325

RIN1 Information on inventor provided before grant (corrected)

Inventor name: CINOTTO, GIUSEPPE