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EP1987257B1 - Pneumatic drive system - Google Patents

Pneumatic drive system Download PDF

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Publication number
EP1987257B1
EP1987257B1 EP07702849A EP07702849A EP1987257B1 EP 1987257 B1 EP1987257 B1 EP 1987257B1 EP 07702849 A EP07702849 A EP 07702849A EP 07702849 A EP07702849 A EP 07702849A EP 1987257 B1 EP1987257 B1 EP 1987257B1
Authority
EP
European Patent Office
Prior art keywords
control valve
valve means
output unit
drive system
pneumatic
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.)
Not-in-force
Application number
EP07702849A
Other languages
German (de)
French (fr)
Other versions
EP1987257A1 (en
Inventor
Dieter Waldmann
Jan-Peter Bender
José ARANA
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.)
Festo SE and Co KG
Original Assignee
Festo SE and Co KG
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 Festo SE and Co KG filed Critical Festo SE and Co KG
Publication of EP1987257A1 publication Critical patent/EP1987257A1/en
Application granted granted Critical
Publication of EP1987257B1 publication Critical patent/EP1987257B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/06—Servomotor systems without provision for follow-up action; Circuits therefor involving features specific to the use of a compressible medium, e.g. air, steam
    • F15B11/064—Servomotor systems without provision for follow-up action; Circuits therefor involving features specific to the use of a compressible medium, e.g. air, steam with devices for saving the compressible medium
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/202—Externally-operated valves mounted in or on the actuator
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/225—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke with valve stems operated by contact with the piston end face or with the cylinder wall
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/421—Flow control characterised by the type of actuation mechanically
    • F15B2211/424—Flow control characterised by the type of actuation mechanically actuated by an output member of the circuit
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy

Definitions

  • the invention relates to a pneumatic drive system, comprising at least one pneumatic drive having a drive housing and a driven in this regard by Druck Kunststoffbeetzschung output unit, wherein the output unit includes a driven piston which divides two working chambers of the drive housing from each other, one or both connected to a pneumatic control line are switchable in the course between an air-saving and in this respect a larger flow cross-section openable control valve means which are assigned depending on the position of the output unit activatable actuating means which can cause a switching of the control valve means in the Lucasspar too when the output unit due to the Through this control valve means in the pneumatic drive incoming compressed air has reached a stroke end position or a short before lying position.
  • One from the EP 0771396 B1 known pneumatic drive system of this type includes a pneumatic crusher designed as Krustenbrecherzylinder which is vertically aligned in the usual position of use and includes a controlled by pressurized pressurized optionally lowerable or liftable output unit whose task is to immerse in a predetermined cycle in a molten aluminum bath, in order to break up a material crust possibly formed on its surface.
  • the direction of movement of the output unit is predetermined by a directional specification valve.
  • a plunger valve control valve means are switched, which can be switched between a maximum flow enabling open position and the air flow completely shut-off air saving.
  • the control valve means are in the open position, so that a high actuating force can be provided. Shortly before reaching the maximum retracted stroke end position, however, the output unit switches the control valve means into the air-saving position so that no further compressed air can flow in. This prevents excessive filling of the associated working chamber and brings about an air consumption saving. If a pressure drop occurs due to systemic leakage in the clogged air volume, the output unit drops so far until the control valve means switch back to the open position, so that compressed air is pumped and the output unit is moved back into the retracted stroke end position.
  • the DE 10 2004 029 990 A1 describes a pneumatic cylinder with cushioning, the piston shuts off an exhaust passage when reaching its end position, so that the fluid can only flow through a throttle channel.
  • a throttle effective with respect to injected fluid is used to build up a backpressure for braking a piston.
  • control valve means are designed so that the air-saving is compared to the open position a smaller flow cross-section releasing throttle position.
  • the air-saving is thus no longer formed as the air flow completely occlusive shut-off, but as a throttle position, the continue to allow - albeit reduced compared to the open position - air flow.
  • a saving in compressed air is thus not possible to the same extent as in the prior art discussed above.
  • the particular advantage of the embodiment according to the invention lies in the at least largely avoiding oscillating movements of the output unit relative to the drive housing in the Hubendlagen. Due to the constant Beernachströmung in the working chamber, the output unit can be reliably held in its stroke end position, so that frequent switching of the control valve means with resulting wear does not occur and also ongoing disturbing vibrations of the pneumatic drive can be largely excluded.
  • control valve means in such a way that the flow cross-section released in the throttle position has a dimension which, taking into account the air pressure present on the input side of the control valve means, determines a flow which lies in the region of the leakage discharge occurring in the system section arranged downstream of the control valve means.
  • the resulting flow should expediently correspond at least to the leakage discharge.
  • the output unit is reliably held. Without causing excessive pressure increase in the powered working chamber.
  • Particularly expedient is a pertinent interpretation that the predetermined flow in the area of interpretation permissible leakage flow is.
  • the leakage occurring for example, between the output unit and the drive housing or in the region of fluid line connection points is within the permissible range, this is constantly compensated and the retracted output unit remains fixed in its stroke end position. Only when the leakage occurring in the system exceeds the permissible value, occur due to the low Gutnachbuch on the aforementioned position instabilities of the output unit, which is practically synonymous with an advantageous wear indicator, because of the optionally occurring in the region of the stroke end position reciprocating movements of the Output unit can be concluded that one or more of the components of the drive system has exceeded its reliable wear limit and should be replaced.
  • inventive measures can be implemented particularly advantageous in a trained as a linear actuator pneumatic drive. Nevertheless, they can be realized, for example, in rotary actuators or rotary actuators.
  • the pneumatic drive designed as a linear drive is preferably a pneumatic cylinder, the output unit of which has a piston rod protruding from the drive housing.
  • the piston rod may be provided on the front side with a shock element, which is particularly suitable to pierce the crust of a molten aluminum bath.
  • control valve means of the type described can be switched on in both control lines or in only one control line. Accordingly, the effect explained in both or only at a stroke end position of the output unit.
  • control valve means it is advantageous for the control valve means to be preceded on the input side by a directional specification valve which is connected or connectable to a compressed air source supplying the operating pressure and by means of whose switching position the stroke direction of the output unit can be predetermined.
  • the directional specification valve is in particular a 5/2-way valve.
  • a particularly compact arrangement results when at least the control valve means and the pneumatic drive are combined to form a structural unit.
  • the optional directional control valve may also be part of this structural unit.
  • the actuating means associated with the control valve means expediently contain response means arranged directly on or in the drive housing which respond to them at or above a certain position of the output unit and cause the switching of the control valve means from the open position into the throttle position.
  • the response means may be designed for purely mechanical or for the electrical actuation of the control valve means.
  • mechanical response means comprise at least one plunger member projecting in the stroke of the output unit and displaceably mounted.
  • control valve means have adjustment means that allow a variable specification of the released in the throttle position flow cross-section.
  • the flow rate occurring in the throttle position can be adjusted as needed.
  • FIG. 1 shows a circuit diagram of a particularly advantageous equipped pneumatic drive system.
  • pneumatic drive system includes a preferably designed as a linear actuator pneumatic drive 2 and its operating mode controlling, designated overall by reference numeral 3 control device. If required, these components can be combined to form a compact unit.
  • the pneumatic drive 2 includes a housing having a longitudinal shape, designated as a drive housing 4, and a movable output unit 6 in this respect, with the execution of mutually opposite linear working movements 5a, 5b.
  • the pneumatic drive 2 is designed as equipped with a piston rod 7 pneumatic cylinder.
  • the piston rod 7 is part of the output unit 6 and at one end attached to a displaceably arranged in the interior of the drive housing 4 output piston 8.
  • the output piston 8 divides the interior of the drive housing 4 in a rear-side first working chamber 12 and a front, displaced by the piston rod 7 displaceable second working chamber 13.
  • the end face of the drive housing 4 outstanding end portion of the piston rod 7 is the force tap.
  • the pneumatic drive 2 could also be a rodless linear drive.
  • the piston rod 7 would then occur another Kraftabgriffsglied, for example, a longitudinal slot of the drive housing 4 enforcing driver.
  • the pneumatic drive system 1 is suitable for any application. In a particularly advantageous manner, it can be used in the production and / or processing of aluminum, wherein the pneumatic drive 2 then forms a so-called Krustenbrecherzylinder. The further description should be based on this application, but also applies to other applications.
  • the output unit 6 can be driven to the aüsfahrenden work movement 5a, wherein it dives after covering a certain distance in the molten metal, while piercing the possibly formed on the surface of the melt material crust by means of the impact element 14.
  • the material crust is characterized broken up.
  • the output unit 6 then moves up to her retracted Hubendlage opposite, not shown extended Hubendlage. Both stroke end positions are expediently predetermined by the output unit 6 striking in a manner not shown on a housing-fixed stop surface, which may be provided in particular on the associated end-side end wall 2a, 2b of the drive housing 4.
  • the extended output unit 6 can be driven to its retracting working movement 5b, where it is pulled back completely out of the molten metal until it is finally back in the retracted Hubendlage.
  • the pressurization which causes the desired working movement 5a, 5b is determined by a directional specification valve 11 of the control device 3. This is on the one hand to a standing under the desired operating pressure compressed air available compressed air source 15 and connected to the atmosphere 16. On the other hand, it is connected to the first working chamber 12 via a first fluidic control line 17 and to the second working chamber 13 via a second fluidic control line 18. It can be selectively positioned in one of two switching positions, wherein in each case a working chamber 12 or 13 compressed air is supplied, while at the same time the respective other working chamber 13 or 12 is vented. The easiest way to realize this functionality is through a 5/2-way valve as shown.
  • the actuation of the directional specification valve 11 is preferably carried out electrically or electromagnetically. It may be a directly actuated or a pilot operated valve. To realize the desired functionality it can Also composed of several functionally linked individual valves, for example, from two 3/2-way valves.
  • first control valve means 22 are turned on.
  • second control valve means 23 can be used. Both control valve means 22, 23 can optionally assume the open position 24 shown in the drawing or a throttle position 25 which functions, inter alia, as an air-saving function.
  • the control valve means 22, 23 are each designed as a two-position valve and contain only a symbolically indicated control valve member 26 which defined by its currently occupied position either the open position 24 or the throttle position 25.
  • control valve means 22, 23 are constantly acted upon in the direction of the open position.
  • the basic position of the control valve means 22, 23 is thus the open position 24.
  • the open position 24 of the compressed air is provided a maximum flow area available. This is preferably chosen so that the compressed air when flowing through the control valve means 22, 23 experiences no or at least no appreciable throttling.
  • the released flow cross-section may in particular correspond to the nominal cross-section of the respectively assigned control line 17, 18.
  • a free flow cross section for the passage into the connected working chamber 12 or 13 are available.
  • the released in the throttle position 25 flow cross-section is, however, less than that of the open position, so that the flowing therethrough Compressed air is throttled.
  • the input pressure normally corresponds to the operating pressure provided by the compressed air source 15, unless a throttling point serving to reduce the pressure is switched on between the compressed air source 15 and the control valve means 22, 23 (not shown).
  • the flow cross-section released in the throttle position 25 preferably has a size such that in the throttle position 25, taking into account the air pressure present on the input side of the control valve means 22, 23, a flow rate is established which is located in the region of the airflow occurring due to leakage, which is located in the control valve means 22, 23 downstream system section permissibly occurs due to tolerance.
  • a certain leakage flow is unavoidable due to not completely excludable system leaks.
  • Small amounts of compressed air can occur in particular at line connection points or in the dynamically sealed areas between the output unit 6 and the drive housing 4. If the throttle position is present, compressed air is always fed into the connected working chamber 12 or 13 to the extent that it escapes at the same time as a result of leakage. Even if this flow rate is not exactly adjustable, it should at least be within the range of permissible leakage throughput, and as a precaution, you can choose a preset compared to the permissible one Leakage throughput has a slightly larger inflow rate.
  • control valve means 22, 23 may have symbolically indicated by an arrow adjustment means 28 which allow a variable and in particular stepless specification of the released in the throttle position 25 flow cross-section.
  • the two control valve means 22, 23 are each associated with actuating means 32 which enable a position-dependent activation and preferably also deactivation of the control valve means 22, 23 from the axial position of the output unit 6.
  • the actuating means 32 for a mechanical actuation of the control valve means 22, 23 are formed. They contain response means 33, which are embodied here in the form of a displaceably mounted in the longitudinal direction of the output unit 6 ram member and the starting from one of the two end walls 2a, 2b axially into the interior of the drive housing 4 and thereby protrude the output piston 8:
  • the response means 33 are coupled for movement with the control valve member 26 and therefore take in the basic position of the control valve means 22, 23 a due to the action of the actuating means 32 belonging to Beauftschungsstoff 27 as far as possible axially into the interior of the drive housing 4 projecting response position.
  • the output unit 6 approaching a Hubendlange meets with its output piston 8 before reaching the Hubendlage on the located in their Anschbig response 33.
  • These include 33 such as the associated actuating means 32 to those control valve means 22 or 23, for the compressed air supply to the each other working chamber 12, 13 are responsible.
  • the output unit 6 cooperates in the region of the retracted stroke end position with those actuating means 32 which are associated with the second control valve means 23 responsible for the compressed air supply into the second working chamber 13.
  • the output unit 6 cooperates with the first control valve means 22 responsible for supplying the first working chamber 12.
  • the arrangement is such that the output unit 6 first acts on the response means 33 when it has approached a distance "S" of the associated stroke end position.
  • the response means 33 are pushed back by the output unit 6, which with simultaneous compression of the resilient urging means 27, a switching of the associated control valve means 22 or 23 from the previously occupied open position in the throttle position causes.
  • a typical duty cycle of the exemplary pneumatic drive system 1 is as follows.
  • the starting point is the retracted stroke end position of the output unit 6 indicated by the dot-dash line.
  • the second control valve means 23 are in the throttle position due to the activated actuating means 32, while the first control valve means 22 assume the open position.
  • the output unit 6 cooperates with the actuating means 32 of the first control valve means 22 and switches them into the throttle position 25, so that the per unit of time further inflowing amount of compressed air is reduced.
  • the directional specification valve 11 is switched to the second switching position by, for example, time-controlled or position-dependent controlled actuation. It then takes place the same sequence of movements as just described, but now the output unit 6 executes the retracting output movement 5b and leaves the molten metal again. As soon as the output unit 6 encounters the response means 33 of the second control valve means 23, the switchover of the latter into the throttle position 25 begins, so that the air flow flowing in from then into the second working chamber 13 is reduced.
  • a new duty cycle begins with the renewed switching of the directional specification valve 11.
  • the described wear indicator also works, of course, with respect to the first control valve means 22, when the output unit 6 is exposed in the extended stroke end position of a counter-force acting in the retraction direction, for example when the pneumatic drive 2 is used with a different orientation than described above.
  • non-contact response means can also be used, in particular so-called reed switches or other position sensors. In this case, the switching of the control valve means 22, 23 would take place by means of electrical signals.
  • control valve means 22, 23 are combined with the pneumatic drive 2 to form a compact structural unit. If necessary, even the directional specification valve 11 incorporated into this unit, together with the existing control lines 17, 18th
  • control valve means can also be switched on in the course of only one of the two control lines 17, 18.
  • control valve means can also be switched on in the course of only one of the two control lines 17, 18.
  • the first control line 17 could in this case be a simple line without valve means turned on.
  • a plurality of pneumatic actuators may also be contained in the pneumatic drive system 1.
  • Each pneumatic drive 2 are preferably assigned their own control valve means 22, 23.
  • the directional specification valve 11 can then be used as needed for the simultaneous control of several pneumatic drives 2.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Fluid-Driven Valves (AREA)
  • Actuator (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

It is a question of a pneumatic drive system comprising at least one pneumatic drive (2) possessing a drive housing (4) and an output drive unit (6) able to be shifted in relation to it by the action of compressed air, the output drive unit (6) including an output drive piston (8), which in the drive housing (4) separates two working chambers (12 and 13) from one another, one or both of such chambers being connected with a pneumatic control line (17 and 18), such line having control valve means (22 and 23) able to be switched over between an air economy position and an open position (24) making available a flow cross section which is larger than that of the air economy position, such control valve means being provided with actuating means (32) able to be activated in a manner dependent on the position of the output drive unit (6), such actuating means being able to cause a switching over of the control valve means (22 and 23) into the air economy position, when the output drive unit (6), owing to the compressed air flowing through the control valve means (22 and 23) into the pneumatic drive (2), has reached an end of stroke position or a position just short thereof. The air economy setting has the particular feature that it is in the form of a choking setting (25) opening up a flow cross section which is smaller than in the open position (24).

Description

Die Erfindung betrifft ein pneumatisches Antriebssystem, mit mindestens einem Pneumatikantrieb, der ein Antriebsgehäuse und eine diesbezüglich durch Druckluftbeaufschlagung bewegbare Abtriebseinheit aufweist, wobei die Abtriebseinheit einen Abtriebskolben enthält, der in dem Antriebsgehäuse zwei Arbeitskammern voneinander abteilt, von denen eine oder beide an eine pneumatische Steuerleitung angeschlossen sind, in deren Verlauf zwischen einer Luftsparstellung und einer diesbezüglich einen größeren Strömungsquerschnitt freigebenden Offenstellung umschaltbare Steuerventilmittel eingeschaltet sind, denen in Abhängigkeit von der Position der Abtriebseinheit aktivierbare Betätigungsmittel zugeordnet sind, die ein Umschalten der Steuerventilmittel in die Luftsparstellung hervorrufen können, wenn die Abtriebseinheit aufgrund der durch diese Steuerventilmittel hindurch in den Pneumatikantrieb zuströmenden Druckluft eine Hubendlage oder eine kurz davor liegende Position erreicht hat.The invention relates to a pneumatic drive system, comprising at least one pneumatic drive having a drive housing and a driven in this regard by Druckluftbeaufschlagung output unit, wherein the output unit includes a driven piston which divides two working chambers of the drive housing from each other, one or both connected to a pneumatic control line are switchable in the course between an air-saving and in this respect a larger flow cross-section openable control valve means which are assigned depending on the position of the output unit activatable actuating means which can cause a switching of the control valve means in the Luftsparstellung when the output unit due to the Through this control valve means in the pneumatic drive incoming compressed air has reached a stroke end position or a short before lying position.

Ein aus der EP 0771396 B1 bekanntes pneumatisches Antriebssystem dieser Art enthält einen als Krustenbrecherzylinder ausgebildeten Pneumatikantrieb, der in der üblichen Gebrauchslage vertikal ausgerichtet ist und der eine durch gesteuerte Druckluftbeaufschlagung wahlweise absenkbare oder anhebbare Abtriebseinheit umfasst, deren Aufgabe es ist, gemäß einem vorgegebenen Zyklus in ein Aluminiumschmelzbad einzutauchen, um eine an dessen Oberfläche eventuell ausgebildete Materialkruste aufzubrechen. Die Bewegungsrichtung der Abtriebseinheit wird durch ein Richtungsvorgabeventil vorgegeben. In den Verlauf der an die unten liegende Arbeitskammer des Pneumatikzylinders angeschlossenen Steuerleitung sind von einem Stößelventil gebildete Steuerventilmittel eingeschaltet, die zwischen einer einen maximalen Durchfluss ermöglichenden Offenstellung und einer die Luftströmung komplett absperrenden Luftsparstellung umschaltbar sind. Während des größten Teils der Hubbewegung der Abtriebseinheit befinden sich die Steuerventilmittel in der Offenstellung, sodass eine hohe Stellkraft zur Verfügung gestellt werden kann. Kurz vor Erreichen der maximal eingefahrenen Hubendlage jedoch schaltet die Abtriebseinheit die Steuerventilmittel in die Luftsparstellung um, sodass keine weitere Druckluft mehr nachströmen kann. Dies verhindert ein übermäßiges Füllen der zugeordneten Arbeitskammer und bringt eine Luftverbrauchseinsparung mit sich. Wenn in dem eingesperrten Luftvolumen aufgrund systembedingter Leckage ein Druckabfall auftritt, sinkt die Abtriebseinheit aufgrund ihres Gewichts so weit ab, bis die Steuerventilmittel wieder in die Offenstellung umschalten, sodass Druckluft nachgepumpt wird und die Abtriebseinheit neuerlich in die eingefahrene Hubendlage zurückbewegt wird.One from the EP 0771396 B1 known pneumatic drive system of this type includes a pneumatic crusher designed as Krustenbrecherzylinder which is vertically aligned in the usual position of use and includes a controlled by pressurized pressurized optionally lowerable or liftable output unit whose task is to immerse in a predetermined cycle in a molten aluminum bath, in order to break up a material crust possibly formed on its surface. The direction of movement of the output unit is predetermined by a directional specification valve. In the course of the connected to the lower working chamber of the pneumatic cylinder control line formed by a plunger valve control valve means are switched, which can be switched between a maximum flow enabling open position and the air flow completely shut-off air saving. During most of the lifting movement of the output unit, the control valve means are in the open position, so that a high actuating force can be provided. Shortly before reaching the maximum retracted stroke end position, however, the output unit switches the control valve means into the air-saving position so that no further compressed air can flow in. This prevents excessive filling of the associated working chamber and brings about an air consumption saving. If a pressure drop occurs due to systemic leakage in the clogged air volume, the output unit drops so far until the control valve means switch back to the open position, so that compressed air is pumped and the output unit is moved back into the retracted stroke end position.

So vorteilhaft die bekannte Luftsparmaßnahme auch ist, hat sie doch den Nachteil, dass durch das in Verbindung mit dem Nachpumpen der Druckluft häufige Öffnen und Schließen der Steuerventilmittel ein nicht unerheblicher Verschleiß auftreten kann. Des Weiteren können die durch das zyklische Nachpumpen hervorgerufenen Nachstellbewegungen der Abtriebseinheit zu Erschütterungen führen, die für den Betrieb des pneumatischen Antriebssystems oder der damit ausgestatteten Anlage störend oder gar schädigend sein können.As advantageous as the known air-saving measure is, it nevertheless has the disadvantage that a considerable wear can occur due to the frequent opening and closing of the control valve means in connection with the pumping-back of the compressed air. Furthermore, the adjustment movements of the output unit caused by the cyclic Nachpumpen may lead to vibrations that are responsible for the operation of the pneumatic Drive system or the system equipped with it can be disturbing or even damaging.

Die gleiche Problematik tritt auch bei dem in der WO 02/14698 A1 beschriebenen pneumatischen Antriebssystem zutage. Dieses unterscheidet sich von dem vorstehend zitierten im Wesentlichen nur dadurch, dass die Offenstellung als Drosselstellung ausgebildet ist, um die Befüllintensität des Pneumatikantriebes zu Gunsten eines weiter reduzierten Luftverbrauchs zu verringern. Bei Erreichen der Hubendlage der Abtriebseinheit werden die Steuerventilmittel wiederum in eine Schließstellung umgeschaltet.The same problem occurs also in the in the WO 02/14698 A1 described pneumatic drive system. This differs from the above-cited essentially only in that the open position is designed as throttle position in order to reduce the filling intensity of the pneumatic drive in favor of a further reduced air consumption. Upon reaching the stroke end position of the output unit, the control valve means are in turn switched to a closed position.

Die DE 10 2004 029 990 A1 beschreibt einen Pneumatikzylinder mit Endlagendämpfung, wobei der Kolben bei Erreichen seiner Endlage einen Auslasskanal absperrt, so dass das Fluid nur noch über einen Drosselkanal abströmen kann. Im Falle der DE 101 38 026 C2 wird eine in bezug auf eingespeistes Fluid wirksame Drossel eingesetzt, um einen zum Abbremsen eines Kolbens dienenden Gegendruck aufzubauen.The DE 10 2004 029 990 A1 describes a pneumatic cylinder with cushioning, the piston shuts off an exhaust passage when reaching its end position, so that the fluid can only flow through a throttle channel. In case of DE 101 38 026 C2 For example, a throttle effective with respect to injected fluid is used to build up a backpressure for braking a piston.

Es ist die Aufgabe der vorliegenden Erfindung, ein pneumatisches Antriebssystem der eingangs genannten Art zu schaffen, das im Betrieb eine verringerte mechanische Beanspruchung erfährt.It is the object of the present invention to provide a pneumatic drive system of the type mentioned, which undergoes a reduced mechanical stress during operation.

Zur Lösung dieser Aufgabe sind die Steuerventilmittel so ausgebildet, dass die Luftsparstellung eine im Vergleich zur Offenstellung einen geringeren Strömungsquerschnitt freigebende Drosselstellung ist.To solve this problem, the control valve means are designed so that the air-saving is compared to the open position a smaller flow cross-section releasing throttle position.

Abweichend vom Stand der Technik ist die Luftsparstellung somit nicht mehr als den Luftdurchfluss komplett verschließende Absperrstellung ausgebildet, sondern als Drosselstellung, die weiterhin einen - wenn auch gegenüber der Offenstellung reduzierten - Luftdurchfluss zulässt. Eine Einsparung an Druckluft ist somit zwar nicht in dem Maße wie bei dem eingangs diskutierten Stand der Technik möglich. Da der Durchfluss jedoch gegenüber der Offenstellung reduziert ist, steigt der in der Arbeitskammer herrschende Druck nur langsam an, sodass vor allem bei kurzen Arbeitstaktzeiten ein Anstieg des Arbeitskammerdruckes auf den auch als Versorgungsdruck bezeichenbaren Betriebsdruck vermieden werden kann. Der besondere Vorteil der erfindungsgemäßen Ausgestaltung liegt aber in der zumindest weitestgehenden Vermeidung oszillierender Bewegungen der Abtriebseinheit relativ zum Antriebsgehäuse in den Hubendlagen. Durch die ständige Luftnachströmung in die Arbeitskammer kann die Abtriebseinheit zuverlässig in ihrer Hubendlage festgehalten werden, sodass ein häufiges Umschalten der Steuerventilmittel mit daraus resultierendem Verschleiß unterbleibt und auch fortwährende störende Erschütterungen des Pneumatikantriebes weitgehend ausgeschlossen werden können.Deviating from the prior art, the air-saving is thus no longer formed as the air flow completely occlusive shut-off, but as a throttle position, the continue to allow - albeit reduced compared to the open position - air flow. Although a saving in compressed air is thus not possible to the same extent as in the prior art discussed above. However, since the flow is reduced compared to the open position, the pressure prevailing in the working chamber increases only slowly, so that an increase in the working chamber pressure can be avoided in particular at short operating cycle times to the operating pressure also denominated as supply pressure. The particular advantage of the embodiment according to the invention lies in the at least largely avoiding oscillating movements of the output unit relative to the drive housing in the Hubendlagen. Due to the constant Luftnachströmung in the working chamber, the output unit can be reliably held in its stroke end position, so that frequent switching of the control valve means with resulting wear does not occur and also ongoing disturbing vibrations of the pneumatic drive can be largely excluded.

Es besteht insbesondere die Möglichkeit, die Steuerventilmittel so auszubilden, dass der in der Drosselstellung freigegebene Strömungsquerschnitt ein Maß aufweist, das unter Berücksichtigung des eingangsseitig an den Steuerventilmitteln anstehenden Luftdruckes einen Durchfluss vorgibt, der im Bereich des in dem den Steuerventilmitteln nachgeordneten Systemabschnitt auftretenden Leckageabflusses liegt. Der sich ergebende Durchfluss sollte zweckmäßigerweise zumindest dem Leckageabfluss entsprechen. Dadurch wird die Abtriebseinheit zuverlässig.festgehalten, ohne einen übermäßigen Druckanstieg in der gespeisten Arbeitskammer hervorzurufen.In particular, it is possible to design the control valve means in such a way that the flow cross-section released in the throttle position has a dimension which, taking into account the air pressure present on the input side of the control valve means, determines a flow which lies in the region of the leakage discharge occurring in the system section arranged downstream of the control valve means. The resulting flow should expediently correspond at least to the leakage discharge. As a result, the output unit is reliably held. Without causing excessive pressure increase in the powered working chamber.

Besonders zweckmäßig ist eine dahingehende Auslegung, dass der vorgegebene Durchfluss im Bereich des auslegungsbedingt zulässigen Leckageabflusses liegt. Solange dann die beispielsweise zwischen der Abtriebseinheit und dem Antriebsgehäuse oder im Bereich von Fluidleitungs-Verbindungsstellen auftretende Leckage im zulässigen Bereich liegt, wird diese ständig kompensiert und die eingefahrene Abtriebseinheit bleibt in ihrer Hubendlage fixiert. Erst wenn die im System auftretende Leckage den zulässigen Wert überschreitet, treten wegen der zu geringen Luftnachfuhr die eingangs erwähnten Lageinstabilitäten der Abtriebseinheit auf, was praktisch gleichbedeutend mit einer vorteilhaften Verschleißanzeige ist, weil anhand der gegebenenfalls im Bereich der Hubendlage auftretenden hin und her gehenden Bewegungen der Abtriebseinheit darauf geschlossen werden kann, dass eines oder mehrere der Bauteile des Antriebssystems seine zuverlässige Verschleißgrenze überschritten hat und ausgetauscht werden sollte.Particularly expedient is a pertinent interpretation that the predetermined flow in the area of interpretation permissible leakage flow is. As long as the leakage occurring, for example, between the output unit and the drive housing or in the region of fluid line connection points is within the permissible range, this is constantly compensated and the retracted output unit remains fixed in its stroke end position. Only when the leakage occurring in the system exceeds the permissible value, occur due to the low Luftnachfuhr on the aforementioned position instabilities of the output unit, which is practically synonymous with an advantageous wear indicator, because of the optionally occurring in the region of the stroke end position reciprocating movements of the Output unit can be concluded that one or more of the components of the drive system has exceeded its reliable wear limit and should be replaced.

In den Unteransprüchen sind noch weitere vorteilhafte Ausgestaltungen des erfindungsgemäßen Antriebssystems definiert.In the dependent claims, further advantageous embodiments of the drive system according to the invention are defined.

Die erfindungsgemäßen Maßnahmen lassen sich besonders vorteilhaft bei einem als Linearantrieb ausgebildeten Pneumatikantrieb umsetzen. Gleichwohl können sie beispielsweise auch bei Drehantrieben oder Schwenkantrieben realisiert werden.The inventive measures can be implemented particularly advantageous in a trained as a linear actuator pneumatic drive. Nevertheless, they can be realized, for example, in rotary actuators or rotary actuators.

Bei dem als Linearantrieb ausgebildeten Pneumatikantrieb handelt es sich vorzugsweise um einen Pneumatikzylinder, dessen Abtriebseinheit über eine aus dem Antriebsgehäuse herausragende Kolbenstange verfügt. Bei einer vorteilhaften Ausgestaltung als Krustenbrecherzylinder kann die Kolbenstange stirnseitig mit einem Stoßelement versehen sein, das insbesondere geeignet ist, um die Kruste eines Aluminiumschmelzbades zu durchstoßen.The pneumatic drive designed as a linear drive is preferably a pneumatic cylinder, the output unit of which has a piston rod protruding from the drive housing. In an advantageous embodiment as Krustenbrecherzylinder the piston rod may be provided on the front side with a shock element, which is particularly suitable to pierce the crust of a molten aluminum bath.

In Abhängigkeit vom Anwendungsfall können in beide Steuerleitungen oder in nur eine Steuerleitung Steuerventilmittel der geschilderten Art eingeschaltet sein. Dementsprechend ergibt sich der erläuterte Effekt bei beiden oder nur bei einer Hubendlage der Abtriebseinheit.Depending on the application, control valve means of the type described can be switched on in both control lines or in only one control line. Accordingly, the effect explained in both or only at a stroke end position of the output unit.

In jedem Fall ist es von Vorteil, wenn den Steuerventilmitteln eingangsseitig ein Richtungsvorgabeventil vorgeschaltet ist, das mit einer den Betriebsdruck liefernden Druckluftquelle verbunden oder verbindbar ist und durch dessen Schaltstellung die Hubrichtung der Abtriebseinheit vorgegeben werden kann. Bei dem Richtungsvorgabeventil handelt es sich insbesondere um ein 5/2-Wegeventil.In any case, it is advantageous for the control valve means to be preceded on the input side by a directional specification valve which is connected or connectable to a compressed air source supplying the operating pressure and by means of whose switching position the stroke direction of the output unit can be predetermined. The directional specification valve is in particular a 5/2-way valve.

Eine besonders kompakte Anordnung ergibt sich, wenn zumindest die Steuerventilmittel und der Pneumatikantrieb zu einer Baueinheit zusammengefasst sind. Auch das gegebenenfalls vorhandene Richtungsvorgabeventil kann Bestandteil dieser Baueinheit sein.A particularly compact arrangement results when at least the control valve means and the pneumatic drive are combined to form a structural unit. The optional directional control valve may also be part of this structural unit.

Die den Steuerventilmitteln zugeordneten Betätigungsmittel enthalten zweckmäßigerweise unmittelbar am oder im Antriebsgehäuse angeordnete Ansprechmittel, die bei oder ab einer bestimmten Position der Abtriebseinheit auf diese ansprechen und das Umschalten der Steuerventilmittel aus der Offenstellung in die Drosselstellung veranlassen. Dabei können die Ansprechmittel zur rein mechanischen oder auch zur elektrischen Betätigung der Steuerventilmittel ausgebildet sein. Mechanische Ansprechmittel enthalten zweckmäßigerweise mindestens ein in den Hubweg der Abtriebseinheit ragendes, verschiebbar gelagertes Stößelglied.The actuating means associated with the control valve means expediently contain response means arranged directly on or in the drive housing which respond to them at or above a certain position of the output unit and cause the switching of the control valve means from the open position into the throttle position. The response means may be designed for purely mechanical or for the electrical actuation of the control valve means. Advantageously, mechanical response means comprise at least one plunger member projecting in the stroke of the output unit and displaceably mounted.

Um insbesondere einen Einsatz mit unterschiedlichen Betriebsdrücken zu ermöglichen, ist es von Vorteil, wenn die Steuerventilmittel über Einstellmittel verfügen, die eine variable Vorgabe des in der Drosselstellung freigegebenen Strömungsquerschnittes ermöglichen. Somit kann die in der Drosselstellung auftretende Strömungsrate nach Bedarf justiert werden.In particular, to enable use with different operating pressures, it is advantageous if the control valve means have adjustment means that allow a variable specification of the released in the throttle position flow cross-section. Thus, the flow rate occurring in the throttle position can be adjusted as needed.

Nachfolgend wird die Erfindung anhand der beiliegenden Zeichnung näher erläutert. Die einzige Figur (Figur 1) zeigt ein Schaltbild eines in besonders vorteilhafter Weise ausgestatteten pneumatischen Antriebssystems.The invention will be explained in more detail with reference to the accompanying drawings. The only figure ( FIG. 1 ) shows a circuit diagram of a particularly advantageous equipped pneumatic drive system.

Das in seiner Gesamtheit mit Bezugsziffer 1 bezeichnete pneumatische Antriebssystem enthält einen bevorzugt als Linearantrieb ausgebildeten Pneumatikantrieb 2 und eine dessen Betriebsweise steuernde, insgesamt mit Bezugsziffer 3 bezeichnete Steuereinrichtung. Diese Komponenten können bei Bedarf zu einer kompakten Baueinheit zusammengefasst sein.The designated in its entirety by reference numeral 1 pneumatic drive system includes a preferably designed as a linear actuator pneumatic drive 2 and its operating mode controlling, designated overall by reference numeral 3 control device. If required, these components can be combined to form a compact unit.

Der Pneumatikantrieb 2 enthält ein Längsgestalt aufweisendes, als Antriebsgehäuse 4 bezeichnetes Gehäuse und eine diesbezüglich unter Ausführung einander entgegengesetzter linearer Arbeitsbewegungen 5a, 5b bewegliche Abtriebseinheit 6.The pneumatic drive 2 includes a housing having a longitudinal shape, designated as a drive housing 4, and a movable output unit 6 in this respect, with the execution of mutually opposite linear working movements 5a, 5b.

Vorzugsweise ist der Pneumatikantrieb 2 als mit einer Kolbenstange 7 ausgestatteter Pneumatikzylinder konzipiert. Die Kolbenstange 7 ist Bestandteil der Abtriebseinheit 6 und einenends an einem im Innern des Antriebsgehäuses 4 verschiebbar angeordneten Abtriebskolben 8 befestigt.Preferably, the pneumatic drive 2 is designed as equipped with a piston rod 7 pneumatic cylinder. The piston rod 7 is part of the output unit 6 and at one end attached to a displaceably arranged in the interior of the drive housing 4 output piston 8.

Der Abtriebskolben 8 unterteilt den Innenraum des Antriebsgehäuses 4 in eine rückseitige erste Arbeitskammer 12 und eine vordere, von der Kolbenstange 7 verschiebbar durchsetzte zweite Arbeitskammer 13. Der stirnseitig aus dem Antriebsgehäuse 4 herausragende Endabschnitt der Kolbenstange 7 dient dem Kraftabgriff.The output piston 8 divides the interior of the drive housing 4 in a rear-side first working chamber 12 and a front, displaced by the piston rod 7 displaceable second working chamber 13. The end face of the drive housing 4 outstanding end portion of the piston rod 7 is the force tap.

Prinzipiell könnte der Pneumatikantrieb 2 auch ein kolbenstangenloser Linearantrieb sein. An die Stelle der Kolbenstange 7 würde dann ein anderes Kraftabgriffsglied treten, beispielsweise ein einen Längsschlitz des Antriebsgehäuses 4 durchsetzender Mitnehmer.In principle, the pneumatic drive 2 could also be a rodless linear drive. In place of the piston rod 7 would then occur another Kraftabgriffsglied, for example, a longitudinal slot of the drive housing 4 enforcing driver.

Das pneumatische Antriebssystem 1 eignet sich für beliebige Anwendungen. In besonders vorteilhafter Weise lässt es sich bei der Herstellung und/oder Verarbeitung von Aluminium einsetzen, wobei der Pneumatikantrieb 2 dann einen sogenannten Krustenbrecherzylinder bildet. Die weitere Beschreibung soll sich an diesem Einsatzfall orientieren, gilt jedoch auch für andere Anwendungen.The pneumatic drive system 1 is suitable for any application. In a particularly advantageous manner, it can be used in the production and / or processing of aluminum, wherein the pneumatic drive 2 then forms a so-called Krustenbrecherzylinder. The further description should be based on this application, but also applies to other applications.

Bei einem Einsatz als Krustenbrecherzylinder ist der Pneumatikantrieb 2, abweichend von der Zeichnungsdarstellung, mit vertikaler Ausrichtung seiner Längsachse mit Abstand oberhalb eines Aluminiumschmelzbades installiert. Das Antriebsgehäuse 4 ist dabei ortsfest an einem Gestell fixiert und die Kolbenstange 7 ragt nach unten. Bei maximal in das Antriebsgehäuse 4 eingefahrener Abtriebseinheit 6 - im Folgenden als "eingefahrene Hubendlage" bezeichnet, die in Figur 1 strichpunktiert angedeutet ist - ist die Abtriebseinheit 6 komplett nach oben aus der Schmelze herausgefahren. Ein stirnseitig am äußeren Ende der Kolbenstange 7 angeordnetes Stoßelement 14 ist dabei zur Oberfläche des nicht näher gezeigten Metallschmelzbades beabstandet. Durch gesteuerte Druckbeaufschlagung kann die Abtriebseinheit 6 zu der aüsfahrenden Arbeitsbewegung 5a angetrieben werden, wobei sie nach Zurücklegen einer gewissen Wegstrecke in das Metallschmelzbad eintaucht, und zwar unter Durchstoßen der sich an der Oberfläche der Schmelze eventuell gebildeten Materialkruste mittels des Stoßelementes 14. Die Materialkruste wird dadurch aufgebrochen. Die Abtriebseinheit 6 bewegt sich dann bis zu ihrer der eingefahrenen Hubendlage entgegengesetzten, nicht näher dargestellten ausgefahrenen Hubendlage. Beide Hubendlagen sind zweckmäßigerweise dadurch vorgegeben, dass die Abtriebseinheit 6 in nicht weiter dargestellter Weise auf eine gehäusefeste Anschlagfläche auftrifft, die insbesondere an der zugeordneten stirnseitigen Abschlusswand 2a, 2b des Antriebsgehäuses 4 vorgesehen sein kann.When used as Krustenbrecherzylinder the pneumatic drive 2, deviating from the drawing representation, with vertical alignment of its longitudinal axis at a distance above a molten aluminum bath installed. The drive housing 4 is fixedly fixed to a frame and the piston rod 7 protrudes downwards. At maximum in the drive housing 4 retracted output unit 6 - hereinafter referred to as "retracted stroke end position", the in FIG. 1 dash-dotted lines is indicated - the output unit 6 is moved out completely from the top of the melt. A front end arranged on the outer end of the piston rod 7 shock element 14 is spaced from the surface of the metal melt bath not shown in detail. By controlled pressurization, the output unit 6 can be driven to the aüsfahrenden work movement 5a, wherein it dives after covering a certain distance in the molten metal, while piercing the possibly formed on the surface of the melt material crust by means of the impact element 14. The material crust is characterized broken up. The output unit 6 then moves up to her retracted Hubendlage opposite, not shown extended Hubendlage. Both stroke end positions are expediently predetermined by the output unit 6 striking in a manner not shown on a housing-fixed stop surface, which may be provided in particular on the associated end-side end wall 2a, 2b of the drive housing 4.

Durch Umsteuerung der Druckluftbeaufschlagung kann die ausgefahrene Abtriebseinheit 6 zu ihrer einfahrenden Arbeitsbewegung 5b angetrieben werden, wobei sie wieder komplett nach oben aus der Metallschmelze herausgezogen wird, bis sie sich letztlich wieder in der eingefahrenen Hubendlage befindet.By reversing the application of compressed air, the extended output unit 6 can be driven to its retracting working movement 5b, where it is pulled back completely out of the molten metal until it is finally back in the retracted Hubendlage.

Die die gewünschte Arbeitsbewegung 5a, 5b hervorrufende Druckbeaufschlagung wird durch ein Richtungsvorgabeventil 11 der Steuereinrichtung 3 bestimmt. Dieses ist einerseits an eine unter dem gewünschten Betriebsdruck stehende Druckluft zur Verfügung stellende Druckluftquelle 15 sowie an die Atmosphäre 16 angeschlossen. Andererseits ist es über eine erste fluidische Steuerleitung 17 an die erste Arbeitskammer 12 und über eine zweite fluidische Steuerleitung 18 an die zweite Arbeitskammer 13 angeschlossen. Es kann wahlweise in einer von zwei Schaltstellungen positioniert werden, wobei jeweils einer Arbeitskammer 12 oder 13 Druckluft zugeführt wird, während gleichzeitig die jeweils andere Arbeitskammer 13 oder 12 entlüftet wird. Am einfachsten lässt sich diese Funktionalität wie abgebildet durch ein 5/2-Wegeventil realisieren.The pressurization which causes the desired working movement 5a, 5b is determined by a directional specification valve 11 of the control device 3. This is on the one hand to a standing under the desired operating pressure compressed air available compressed air source 15 and connected to the atmosphere 16. On the other hand, it is connected to the first working chamber 12 via a first fluidic control line 17 and to the second working chamber 13 via a second fluidic control line 18. It can be selectively positioned in one of two switching positions, wherein in each case a working chamber 12 or 13 compressed air is supplied, while at the same time the respective other working chamber 13 or 12 is vented. The easiest way to realize this functionality is through a 5/2-way valve as shown.

Die Betätigung des Richtungsvorgabeventils 11 erfolgt vorzugsweise elektrisch oder elektromagnetisch. Es kann sich um ein direkt betätigtes oder um ein vorgesteuertes Ventil handeln. Zur Realisierung der gewünschten Funktionalität kann es sich auch aus mehreren funktionell verknüpften Einzelventilen zusammensetzen, beispielsweise aus zwei 3/2-Wegeventilen.The actuation of the directional specification valve 11 is preferably carried out electrically or electromagnetically. It may be a directly actuated or a pilot operated valve. To realize the desired functionality it can Also composed of several functionally linked individual valves, for example, from two 3/2-way valves.

In den Verlauf der ersten Steuerleitung 17 sind erste Steuerventilmittel 22 eingeschaltet. In vergleichbarer Weise finden sich im Verlauf der zweiten Steuerleitung 18 zweite Steuerventilmittel 23. Beide Steuerventilmittel 22, 23 können wahlweise die aus der Zeichnung ersichtliche Offenstellung 24 oder eine unter anderem als Luftsparstellung fungierende Drosselstellung 25 einnehmen. Zweckmäßigerweise sind die Steuerventilmittel 22, 23 jeweils als Zweistellungsventil konzipiert und enthalten ein nur symbolisch angedeutetes Steuerventilglied 26, das durch seine momentan eingenommene Stellung entweder die Offenstellung 24 oder die Drosselstellung 25 definiert.In the course of the first control line 17 first control valve means 22 are turned on. In a comparable manner, in the course of the second control line 18, second control valve means 23 can be used. Both control valve means 22, 23 can optionally assume the open position 24 shown in the drawing or a throttle position 25 which functions, inter alia, as an air-saving function. Conveniently, the control valve means 22, 23 are each designed as a two-position valve and contain only a symbolically indicated control valve member 26 which defined by its currently occupied position either the open position 24 or the throttle position 25.

Durch Beaufschlagungsmittel 27, insbesondere von Federmitteln gebildet, sind die Steuerventilmittel 22, 23 ständig in Richtung der Offenstellung beaufschlagt. Die Grundstellung der Steuerventilmittel 22, 23 ist also die Offenstellung 24.By control means 27, in particular formed by spring means, the control valve means 22, 23 are constantly acted upon in the direction of the open position. The basic position of the control valve means 22, 23 is thus the open position 24.

In der Offenstellung 24 wird der Druckluft ein maximaler Strömungsquerschnitt zur Verfügung gestellt. Dieser ist vorzugsweise so gewählt, dass die Druckluft beim Hindurchströmen der Steuerventilmittel 22, 23 keine oder zumindest keine nennenswerte Drosselung erfährt. Der hierbei freigegebene Strömungsquerschnitt kann insbesondere dem Nennquerschnitt der jeweils zugeordneten Steuerleitung 17, 18 entsprechen.In the open position 24 of the compressed air is provided a maximum flow area available. This is preferably chosen so that the compressed air when flowing through the control valve means 22, 23 experiences no or at least no appreciable throttling. In this case, the released flow cross-section may in particular correspond to the nominal cross-section of the respectively assigned control line 17, 18.

Auch in der Drosselstellung 25 steht der Druckluft ein freier Strömungsquerschnitt zum Übertritt in die angeschlossene Arbeitskammer 12 oder 13 zur Verfügung. Der in der Drosselstellung 25 freigegebene Strömungsquerschnitt ist allerdings geringer als derjenige der Offenstellung, sodass die hindurchströmende Druckluft gedrosselt wird. Solange Druckluft durch die in Drosselstellung befindlichen Steuerventilmittel 22 oder 23 hindurch in die jeweils angeschlossene Arbeitskammer 12 oder 13 zuströmt, herrscht am Ventilausgang der Steuerventilmittel 22, 23 ein geringerer Luftdruck als an dem dem Richtungsvorgabeventil 11 zugeordneten Ventileingang. Der Eingangsdruck entspricht normalerweise dem durch die Druckluftquelle 15 zur Verfügung gestellten Betriebsdruck, sofern nicht zwischen die Druckluftquelle 15 und die Steuerventilmittel 22, 23 eine zur Druckreduzierung dienende Drosselstelle eingeschaltet ist (nicht dargestellt).Also in the throttle position 25 of the compressed air is a free flow cross section for the passage into the connected working chamber 12 or 13 are available. The released in the throttle position 25 flow cross-section is, however, less than that of the open position, so that the flowing therethrough Compressed air is throttled. As long as compressed air flows through the control valve means located in the throttle position 22 or 23 into the respectively connected working chamber 12 or 13, there is a lower air pressure at the valve outlet of the control valve means 22, 23 than at the direction input valve 11 associated with the valve inlet. The input pressure normally corresponds to the operating pressure provided by the compressed air source 15, unless a throttling point serving to reduce the pressure is switched on between the compressed air source 15 and the control valve means 22, 23 (not shown).

Der in der Drosselstellung 25 freigegebene Strömungsquerschnitt weist vorzugsweise eine dahingehende Größe auf, dass in der Drosselstellung 25 unter Berücksichtigung des eingangsseitig an den Steuerventilmitteln 22, 23 anstehenden Luftdruckes ein Durchfluss vorgegeben ist, der im Bereich des aufgrund von Leckage auftretenden Luftabflusses angesiedelt ist, welcher in dem den Steuerventilmitteln 22, 23 nachgeordneten Systemabschnitt toleranzbedingt zulässigerweise auftritt.The flow cross-section released in the throttle position 25 preferably has a size such that in the throttle position 25, taking into account the air pressure present on the input side of the control valve means 22, 23, a flow rate is established which is located in the region of the airflow occurring due to leakage, which is located in the control valve means 22, 23 downstream system section permissibly occurs due to tolerance.

Ein gewisser Leckageabfluss ist aufgrund nicht komplett ausschließbarer Systemundichtigkeiten nicht vermeidbar. Geringe Mengen an Druckluft können insbesondere an Leitungsverbindungsstellen oder in den dynamisch abgedichteten Bereichen zwischen der Abtriebseinheit 6 und dem Antriebsgehäuse 4 auftreten. Liegt die Drosselstellung vor, wird in die angeschlossene Arbeitskammer 12 oder 13 stets Druckluft etwa in dem Maße nachgespeist, wie sie zeitgleich durch Leckage entweicht. Selbst wenn dieser Durchflusswert nicht exakt einstellbar ist, sollte er sich doch zumindest im Bereich des zulässigen Leckagedurchsatzes bewegen, wobei man sicherheitshalber eine Vorgabe wählen kann, die im Vergleich zu dem zulässigen Leckagedurchsatz eine etwas größere Zuströmrate aufweist.A certain leakage flow is unavoidable due to not completely excludable system leaks. Small amounts of compressed air can occur in particular at line connection points or in the dynamically sealed areas between the output unit 6 and the drive housing 4. If the throttle position is present, compressed air is always fed into the connected working chamber 12 or 13 to the extent that it escapes at the same time as a result of leakage. Even if this flow rate is not exactly adjustable, it should at least be within the range of permissible leakage throughput, and as a precaution, you can choose a preset compared to the permissible one Leakage throughput has a slightly larger inflow rate.

Um eine exakte, anwendungsspezifische Justierung zu ermöglichen, können die Steuerventilmittel 22, 23 über symbolisch durch einen Pfeil angedeutete Einstellmittel 28 verfügen, die eine variable und insbesondere stufenlose Vorgabe des in der Drosselstellung 25 freigegebenen Strömungsquerschnittes ermöglichen.In order to allow an exact, application-specific adjustment, the control valve means 22, 23 may have symbolically indicated by an arrow adjustment means 28 which allow a variable and in particular stepless specification of the released in the throttle position 25 flow cross-section.

Den beiden Steuerventilmitteln 22, 23 sind jeweils Betätigungsmittel 32 zugeordnet, die ein von der Axialposition der Abtriebseinheit 6 positionsabhängiges Aktivieren und vorzugsweise auch Deaktivieren der Steuerventilmittel 22, 23 ermöglichen.The two control valve means 22, 23 are each associated with actuating means 32 which enable a position-dependent activation and preferably also deactivation of the control valve means 22, 23 from the axial position of the output unit 6.

Bei der besonders robusten Bauform des Ausführungsbeispiels sind die Betätigungsmittel 32 für ein mechanisches Betätigen der Steuerventilmittel 22, 23 ausgebildet. Sie enthalten Ansprechmittel 33, die hier in Gestalt eines in der Längsrichtung der Abtriebseinheit 6 verschiebbar gelagerten Stößelgliedes ausgeführt sind und die ausgehend von je einer der beiden Abschlusswände 2a, 2b axial in den Innenraum des Antriebsgehäuses 4 hinein- und dabei dem Abtriebskolben 8 entgegenragen:In the particularly robust design of the embodiment, the actuating means 32 for a mechanical actuation of the control valve means 22, 23 are formed. They contain response means 33, which are embodied here in the form of a displaceably mounted in the longitudinal direction of the output unit 6 ram member and the starting from one of the two end walls 2a, 2b axially into the interior of the drive housing 4 and thereby protrude the output piston 8:

Die Ansprechmittel 33 sind mit dem Steuerventilglied 26 bewegungsgekoppelt und nehmen daher in der Grundstellung der Steuerventilmittel 22, 23 eine aufgrund der Aktion der ebenfalls zu den Betätigungsmitteln 32 gehörenden Beaufschlagungsmittel 27 weitestmöglich axial in den Innenraum des Antriebsgehäuses 4 hineinragende Ansprechstellung ein.The response means 33 are coupled for movement with the control valve member 26 and therefore take in the basic position of the control valve means 22, 23 a due to the action of the actuating means 32 belonging to Beaufschlagungsmittel 27 as far as possible axially into the interior of the drive housing 4 projecting response position.

Die sich einer Hubendlange annähernde Abtriebseinheit 6 trifft mit ihrem Abtriebskolben 8 vor Erreichen der Hubendlage auf die sich in ihrer Ansprechstellung befindlichen Ansprechmittel 33. Dabei gehören diese Ansprechmittel 33 wie auch die zugeordneten Betätigungsmittel 32 zu denjenigen Steuerventilmitteln 22 oder 23, die für die Drucklufteinspeisung in die jeweils jenseitige Arbeitskammer 12, 13 verantwortlich sind. Mit anderen Worten kooperiert die Abtriebseinheit 6 im Bereich der eingefahrenen Hubendlage mit denjenigen Betätigungsmitteln 32, die den für die Druckluftzufuhr in die zweite Arbeitskammer 13 verantwortlichen zweiten Steuerventilmitteln 23 zugeordnet sind. In der ausgefahrenen Hubendlage kooperiert die Abtriebseinheit 6 mit den für die Speisung der ersten Arbeitskammer 12 verantwortlichen ersten Steuerventilmitteln 22.The output unit 6 approaching a Hubendlange meets with its output piston 8 before reaching the Hubendlage on the located in their Ansprechstellung response 33. These include 33 such as the associated actuating means 32 to those control valve means 22 or 23, for the compressed air supply to the each other working chamber 12, 13 are responsible. In other words, the output unit 6 cooperates in the region of the retracted stroke end position with those actuating means 32 which are associated with the second control valve means 23 responsible for the compressed air supply into the second working chamber 13. In the extended stroke end position, the output unit 6 cooperates with the first control valve means 22 responsible for supplying the first working chamber 12.

Die Anordnung ist so getroffen, dass die Abtriebseinheit 6 auf die Ansprechmittel 33 erstmals einwirkt, wenn sie sich bis auf eine Wegstrecke "S" der zugeordneten Hubendlage angenähert hat. Beim Zurücklegen dieser restlichen Wegstrecke "S", die praktisch den Ansprechbereich der Ansprechmittel 33 definiert, werden die Ansprechmittel 33 durch die Abtriebseinheit 6 zurückgeschoben, was bei gleichzeitiger Komprimierung der federnden Beaufschlagungsmittel 27 ein Umschalten der zugeordneten Steuerventilmittel 22 oder 23 aus der bis dahin eingenommenen Offenstellung in die Drosselstellung hervorruft.The arrangement is such that the output unit 6 first acts on the response means 33 when it has approached a distance "S" of the associated stroke end position. When covering this remaining distance "S", which practically defines the response range of the response means 33, the response means 33 are pushed back by the output unit 6, which with simultaneous compression of the resilient urging means 27, a switching of the associated control valve means 22 or 23 from the previously occupied open position in the throttle position causes.

Kehrt sich die Bewegungsrichtung der Abtriebseinheit 6 anschließend wieder um, werden die zuvor in die Drosselstellung geschalteten Steuerventilmittel 22 oder 23 durch die zu den Betätigungsmitteln 32 gehörenden Beaufschlagungsmittel 27 in die Offenstellung zurückgeschaltet. Die Ansprechmittel 33 folgen praktisch der zurückweisenden Abtriebseinheit 6 nach, bis sie wieder bei der anfänglichen Ansprechstellung angelangt sind.If the direction of movement of the output unit 6 subsequently reverses again, the control valve means 22 or 23 previously switched into the throttle position are switched back into the open position by the actuating means 27 belonging to the actuating means 32. The response means 33 practically follow the rejecting output unit 6, until they are back to the initial response position.

Ein typischer Arbeitszyklus des beispielhaften pneumatischen Antriebssystems 1 läuft wie folgt ab.A typical duty cycle of the exemplary pneumatic drive system 1 is as follows.

Ausgangspunkt ist die strichpunktiert angedeutete eingefahrene Hubendlage der Abtriebseinheit 6. Hier befinden sich die zweiten Steuerventilmittel 23 aufgrund der aktivierten Betätigungsmittel 32 in der Drosselstellung, während die ersten Steuerventilmittel 22 die Offenstellung einnehmen.The starting point is the retracted stroke end position of the output unit 6 indicated by the dot-dash line. Here, the second control valve means 23 are in the throttle position due to the activated actuating means 32, while the first control valve means 22 assume the open position.

Um nun die ausfahrende Arbeitsbewegung 5a hervorzurufen, wird durch das die abgebildete Schaltstellung einnehmende Richtungsvorgabeventil 11 Druckluft in die erste Steuerleitung 17 eingespeist, während gleichzeitig die zweite Steuerleitung 18 entlüftet wird. Anfänglich ist die Ausfahrgeschwindigkeit der Abtriebseinheit 6 dabei noch etwas reduziert, weil die Druckluft nur gedrosselt aus der zweiten Arbeitskammer 13 ausströmen kann. Sobald jedoch die Abtriebseinheit 6 den Ansprechbereich der den zweiten Steuerventilmitteln 23 zugeordneten Ansprechmittel 33 verlassen hat, steht der durch die Offenstellung 24 der zweiten Steuerventilmittel 23 definierte vollständige Abströmquerschnitt zur Verfügung. Die Abtriebseinheit 6 bewegt sich jetzt mit hoher Geschwindigkeit in Richtung ihrer ausgefahrenen Hubendlage, wobei sie in der Lage ist, eine eventuell im Verfahrweg befindliche Metallkruste eines Metallschmelzbades zu durchstoßen.In order to now cause the extending working movement 5a, 11 compressed air is fed into the first control line 17 by the directional setting valve engaging the illustrated switching position, while at the same time the second control line 18 is vented. Initially, the extension speed of the output unit 6 is still somewhat reduced, because the compressed air can only flow throttled out of the second working chamber 13. However, as soon as the output unit 6 has left the response range of the response means 33 assigned to the second control valve means 23, the complete outflow cross-section defined by the open position 24 of the second control valve means 23 is available. The output unit 6 now moves at high speed in the direction of its extended stroke end position, being able to pierce a possibly located in the travel path metal crust of a molten metal bath.

Kurz vor Erreichen der ausgefahrenen Hubendlage beginnend, kooperiert die Abtriebseinheit 6 mit den Betätigungsmitteln 32 der ersten Steuerventilmittel 22 und schaltet diese in die Drosselstellung 25 um, sodass die pro Zeiteinheit weiter zuströmende Druckluftmenge reduziert wird.Starting shortly before reaching the extended stroke end position, the output unit 6 cooperates with the actuating means 32 of the first control valve means 22 and switches them into the throttle position 25, so that the per unit of time further inflowing amount of compressed air is reduced.

Anschließend wird durch beispielsweise zeitgesteuerte oder auch positionsabhängig gesteuerte Betätigung das Richtungsvorgabeventil 11 in die zweite Schaltstellung umgeschaltet. Es findet dann der gleiche Bewegungsablauf wie eben geschildert statt, wobei nun aber die Abtriebseinheit 6 die einfahrende Abtriebsbewegung 5b ausführt und die Metallschmelze wieder verlässt. Sobald die Abtriebseinheit 6 dabei auf die Ansprechmittel 33 der zweiten Steuerventilmittel 23 trifft, beginnt das Umschalten der Letztgenannten in die Drosselstellung 25, sodass der ab dann in die zweite Arbeitskammer 13 zuströmende Luftstrom reduziert wird.Subsequently, the directional specification valve 11 is switched to the second switching position by, for example, time-controlled or position-dependent controlled actuation. It then takes place the same sequence of movements as just described, but now the output unit 6 executes the retracting output movement 5b and leaves the molten metal again. As soon as the output unit 6 encounters the response means 33 of the second control valve means 23, the switchover of the latter into the throttle position 25 begins, so that the air flow flowing in from then into the second working chamber 13 is reduced.

Aufgrund der oben erläuterten Abmessungen des in der Drosselstellung 25 freigegebenen Strömungsquerschnittes wird hierbei in die zweite Arbeitskammer 13 fortlaufend Druckluft zumindest in einem Maße nachgespeist, dass die auftretende Leckage ausgeglichen wird. Dadurch verharrt die Abtriebseinheit 6 normalerweise unbeweglich in der eingefahrenen Hubendlage. Das Gesamtsystem befindet sich mithin in Ruhe und es treten keine mechanischen Belastungen auf.Due to the above-described dimensions of the released in the throttle position 25 flow cross-section is here in the second working chamber 13 continuously replenished compressed air at least to an extent that the leakage occurring is compensated. As a result, the output unit 6 normally remains immobile in the retracted stroke end position. The entire system is therefore at rest and there are no mechanical stress.

Ein neuer Arbeitszyklus beginnt mit dem neuerlichen Umschalten des Richtungsvorgabeventils 11.A new duty cycle begins with the renewed switching of the directional specification valve 11.

Tritt mit zunehmender Betriebsdauer des pneumatischen Antriebssystems 1 ein vermehrter Verschleiß auf, der zu einer Erhöhung des Leckageabflusses führt, reicht die in der Drosselstellung 25 nachgespeiste Druckluft nicht mehr aus, um die Abtriebseinheit 6 in der eingefahrenen Hubendlage zu fixieren. Vor allem bei vertikalem Einbau hat die Abtriebseinheit 6 daher die Tendenz, sich aus der eingefahrenen Hubendlage zu entfernen. Sobald sie jedoch den Ansprechbereich der Ansprechmittel 33 verlassen hat - beim Ausführungsbeispiel ist dies der Fall, wenn sich die Abtriebseinheit 6 um die Wegstrecke "S" aus der eingefahrenen Hubendlage herausbewegt hat -, wird durch vorübergehendes Umschalten der zweiten Steuerventilmittel 23 in die Offenstellung 24 verstärkt Druckluft in die zweite Arbeitskammer 13 nachgeführt, bis die Abtriebseinheit 6 wieder in die eingefahrene Endlage zurückkehrt und dann die zweiten Steuerventilmittel 23 wieder die Drosselstellung 25 einnehmen.Occurs with increasing operating time of the pneumatic drive system 1 increased wear, which leads to an increase in the leakage flow, the fed in the throttle position 25 compressed air is no longer sufficient to fix the output unit 6 in the retracted Hubendlage. Especially with vertical installation, the output unit 6 therefore has a tendency to move away from the retracted stroke end position. However, once it has left the response range of the response means 33 - in the embodiment, this is the case when the output unit 6 to the Distance "S" has moved out of the retracted Hubendlage - compressed air is fed into the second working chamber 13 by temporarily switching the second control valve means 23 in the open position 24 until the output unit 6 returns to the retracted end position and then the second control valve means 23 again take the throttle position 25.

Diese von außen her erkennbare Oszillationsbewegung mit geringfügigem Hub der Abtriebseinheit 6 fungiert als Verschleißanzeige. Sie ist Ausdruck für eine über dem zulässigen Wert liegende Systemleckage und mithin ein Zeichen für Verschleiß einer oder mehrerer Systemkomponenten. Dies schafft die Möglichkeit, verschlissene Bauteile frühzeitig auszuwechseln, um ständig einen zuverlässigen Betrieb des Antriebssystems 1 zu gewährleisten.This recognizable from the outside oscillation movement with a slight stroke of the output unit 6 acts as a wear indicator. It is an expression of a system leak above the permissible value and thus a sign of wear on one or more system components. This provides the opportunity to replace worn components early in order to constantly ensure reliable operation of the drive system 1.

Die geschilderte Verschleißanzeige funktioniert selbstverständlich auch in Bezug auf die ersten Steuerventilmittel 22, wenn die Abtriebseinheit 6 in der ausgefahrenen Hubendlage einer in Einfahrrichtung wirkenden Gegenkraft ausgesetzt ist, beispielsweise wenn der Pneumatikantrieb 2 mit einer anderen Ausrichtung als der oben beschriebenen eingesetzt wird.The described wear indicator also works, of course, with respect to the first control valve means 22, when the output unit 6 is exposed in the extended stroke end position of a counter-force acting in the retraction direction, for example when the pneumatic drive 2 is used with a different orientation than described above.

Anstelle mechanischer Ansprechmittel 33 können auch berührungslos arbeitende Ansprechmittel eingesetzt werden, insbesondere sogenannte Reed-Schalter oder andere Positionssensoren. In diesem Fall würde das Umschalten der Steuerventilmittel 22, 23 unter Vermittlung elektrischer Signale stattfinden.Instead of mechanical response means 33, non-contact response means can also be used, in particular so-called reed switches or other position sensors. In this case, the switching of the control valve means 22, 23 would take place by means of electrical signals.

Beim Ausführungsbeispiel sind die Steuerventilmittel 22, 23 mit dem Pneumatikantrieb 2 zu einer kompakten Baueinheit zusammengefasst. Bei Bedarf kann auch noch das Richtungsvorgabeventil 11 in diese Baueinheit eingegliedert werden, zusammen mit den vorhandenen Steuerleitungen 17, 18.In the exemplary embodiment, the control valve means 22, 23 are combined with the pneumatic drive 2 to form a compact structural unit. If necessary, even the directional specification valve 11 incorporated into this unit, together with the existing control lines 17, 18th

Abweichend vom Ausführungsbeispiel können Steuerventilmittel auch in den Verlauf nur einer der beiden Steuerleitung 17, 18 eingeschaltet sein. Insbesondere bei einem Einsatz als Krustenbrecherzylinder würde es prinzipiell genügen, nur der mit der zweiten Arbeitskammer 13 kommunizierenden zweiten Steuerleitung 18 die erfindungsgemäßen Steuerventilmittel 23 zuzuordnen. Die erste Steuerleitung 17 könnte in diesem Fall eine einfache Leitung ohne eingeschaltete Ventilmittel sein.Deviating from the exemplary embodiment, control valve means can also be switched on in the course of only one of the two control lines 17, 18. In particular, when used as Krustenbrecherzylinder it would be sufficient in principle, only the second control line 18 communicating with the second working chamber to associate the control valve means 23 according to the invention. The first control line 17 could in this case be a simple line without valve means turned on.

Anstelle nur eines einzigen Pneumatikantriebes 2 können auch mehrere Pneumatikantriebe in dem pneumatischen Antriebssystem 1 enthalten sein. Jedem Pneumatikantrieb 2 sind dabei vorzugsweise eigene Steuerventilmittel 22, 23 zugeordnet. Das Richtungsvorgabeventil 11 kann dann bei Bedarf für die gleichzeitige Ansteuerung mehrerer Pneumatikantriebe 2 eingesetzt werden.Instead of only a single pneumatic drive 2, a plurality of pneumatic actuators may also be contained in the pneumatic drive system 1. Each pneumatic drive 2 are preferably assigned their own control valve means 22, 23. The directional specification valve 11 can then be used as needed for the simultaneous control of several pneumatic drives 2.

Claims (13)

  1. Pneumatic drive system with at least one pneumatic drive (2) which has a drive housing (4) and an output unit (6) movable relative to the former by means of compressed air pressurisation, wherein the output unit (6) contains an output piston (8) dividing two operating chambers (12, 13) in the drive housing (4) from one another and with one or both operating chambers connected to a pneumatic control line (17, 18), in the course of which are inserted control valve means (22, 23) switchable between an air economy position and an open position (24) allowing in this respect a larger flow cross-section, and which are assigned actuating means (32) which may be activated depending on the position of the output unit (6) and are able to generate a switch of the control valve means (22, 23) into the air economy position when the output unit (6), due to the compressed air flowing through these control valve means (22, 23) into the pneumatic drive (2), has reached an end-of-stroke position or a position lying shortly before it, characterised in that the air economy position is a restrictor position (25) allowing a smaller flow cross-section than the open position (24).
  2. Drive system according to claim 1, characterised in that the pneumatic drive or drives (2) is or are a linear drive(s).
  3. Drive system according to claim 1 or 2, characterised in that pneumatic drive or drives (2) is or are a pneumatic cylinder(s), with an output unit (6) containing a piston rod (7) extending out of the end face of the drive housing (4).
  4. Drive system according to claim 3, characterised in that the pneumatic cylinder is a crust-breaking cylinder, carrying on the end face of its piston rod (7) a ram element (14) suitable for piercing the crust of a metal melting bath.
  5. Drive system according to any of claims 1 to 4, characterised in that upstream of the control valve means (22, 23) on the inlet side is a direction setting valve (11) connectable or connected to a compressed air source (15) and able to feed the two control lines (17, 18) with compressed air under operating pressure, or to vent them, alternately in opposite directions.
  6. Drive system according to claim 5, characterised in that the direction setting valve (11) is in the form of a 5/2-way valve.
  7. Drive system according to any of claims 1 to 6, characterised in that at least the control valve means (22, 23) and the pneumatic drive (2) may be combined to form a unit.
  8. Drive system according to any of claims 1 to 7, characterised in that the actuating means (32) contain response means (33) which operate from or at a specific position of the output unit (6), thereby generating the switching of the assigned control valve means (22, 23) into the restrictor position (25).
  9. Drive system according to claim 8, characterised by actuating means (32) designed for the mechanical switching of the control valve means (22, 23), with response means (33) extending into the path of the stroke of the output unit (6) and able to be moved by the latter.
  10. Drive system according to claim 9, characterised in that the mechanical response means (33) contain at least one slidably mounted punch member.
  11. Drive system according to any of claims 8 to 10, characterised in that the actuating means (32) are so designed that they reset the assigned control valve means (22, 23) to the open position (24) when the output unit (6) once again leaves the response range of the response means (33).
  12. Drive system according to any of claims 1 to 11, characterised in that the flow cross-section provided in the restrictor position (25) is of a size which, allowing for the air pressure at the control valve means (22, 23) on the inlet side, presets a flow lying in the range of the acceptable leakage occurring in the system section downstream of the control valve means (22, 23), and expediently corresponding at least to the level of this acceptable leakage outflow.
  13. Drive system according to any of claims 1 to 12, characterised in that the control valve means (22, 23) have setting means (28) for variable presetting of the flow cross-section provided in the restrictor position (25).
EP07702849A 2006-02-21 2007-01-18 Pneumatic drive system Not-in-force EP1987257B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE202006002727U DE202006002727U1 (en) 2006-02-21 2006-02-21 Pneumatic drive system
PCT/EP2007/000398 WO2007096031A1 (en) 2006-02-21 2007-01-18 Pneumatic drive system

Publications (2)

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EP1987257A1 EP1987257A1 (en) 2008-11-05
EP1987257B1 true EP1987257B1 (en) 2009-07-22

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Family Applications (1)

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EP07702849A Not-in-force EP1987257B1 (en) 2006-02-21 2007-01-18 Pneumatic drive system

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US (1) US20090078110A1 (en)
EP (1) EP1987257B1 (en)
AT (1) ATE437309T1 (en)
AU (1) AU2007218273A1 (en)
CA (1) CA2611208C (en)
DE (2) DE202006002727U1 (en)
WO (1) WO2007096031A1 (en)

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CA2611208A1 (en) 2007-08-30
ATE437309T1 (en) 2009-08-15
AU2007218273A1 (en) 2007-08-30
EP1987257A1 (en) 2008-11-05
DE202006002727U1 (en) 2006-04-20
WO2007096031A1 (en) 2007-08-30
DE502007001127D1 (en) 2009-09-03
CA2611208C (en) 2014-02-25
US20090078110A1 (en) 2009-03-26

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