EP0350053B1 - Multiple-stage hydraulic telescopic actuator with control of the extension or retraction of the telescopic parts in an imposed order - Google Patents

Multiple-stage hydraulic telescopic actuator with control of the extension or retraction of the telescopic parts in an imposed order Download PDF

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Publication number
EP0350053B1
EP0350053B1 EP89112435A EP89112435A EP0350053B1 EP 0350053 B1 EP0350053 B1 EP 0350053B1 EP 89112435 A EP89112435 A EP 89112435A EP 89112435 A EP89112435 A EP 89112435A EP 0350053 B1 EP0350053 B1 EP 0350053B1
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EP
European Patent Office
Prior art keywords
intermediate piston
cylinder
valve
piston
base
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Expired - Lifetime
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EP89112435A
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German (de)
French (fr)
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EP0350053A1 (en
Inventor
Gerd BRÄCKELMANN
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Montanhydraulik GmbH
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Montanhydraulik GmbH
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    • 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
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/16—Characterised by the construction of the motor unit of the straight-cylinder type of the telescopic type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/24—Devices, e.g. jacks, adapted for uninterrupted lifting of loads fluid-pressure operated
    • B66F3/25—Constructional features
    • B66F3/26—Adaptations or arrangements of pistons
    • B66F3/28—Adaptations or arrangements of pistons telescopic

Definitions

  • the invention relates to a multi-stage hydraulic telescopic cylinder according to the preamble of claim 1.
  • a telescopic cylinder is described for example in DE-A-2 253 646.
  • the desired extension sequence intermediate stage - final stage is ensured in that a bypass is provided in the cylinder wall, which creates a connection between the cylinder pressure chamber and the pressure chamber of the intermediate piston in the extended end position of the intermediate piston via the intermediate piston head.
  • a hole in the intermediate piston wall must be run over. Running into the bypass on the cylinder wall and passing over the bore in the intermediate piston wall make metallic seals necessary, which do not seal completely, with the result that such telescopic cylinders are not completely stable in the holding situation.
  • the invention is based on the object of designing a generic telescopic system in such a way that its absolute positional stability is ensured in the holding situation.
  • the telescopic cylinder according to the invention which generally avoids bypasses or bores in the critical areas, permits the use of elastic seals, so-called soft seals, at least at those points where a 100% seal is a prerequisite for the absolute positional stability of the cylinder in the holding situation.
  • the solution according to the invention then also builds shorter solutions than bypasses.
  • the solution is also easy to manufacture, assemble and maintain, as well as being low-wear.
  • DE-A-3 021 633 also addresses the fact that in connection with the protection of the connecting line between the cylinder pressure chamber and the pressure chamber of the intermediate stage, a check valve is arranged in parallel by a check valve which can be mechanically actuated when the intermediate piston moves into the extension output stage to the longitudinal axis of the cylinder is not recommended and an arrangement of the valve inclined to the longitudinal axis of the telescopic cylinder is preferable.
  • this then involves considerable manufacturing problems.
  • both the closing body of the valve securing the connecting line between the cylinder pressure chamber and the interior of the intermediate piston are expedient also associated with the so-called adjusting ring return springs assigned to the intermediate piston crown.
  • a branch line that bypasses the valve in the branch line and leads into the connecting line, starting from the connecting line in the intermediate piston bottom that leads to the cylinder annular space above the intermediate piston bottom, leading from the interior of the end piston via the bushing leading from the intermediate piston bottom, through a connecting line spring-loaded valve which can be actuated by pressure medium pressure on the cylinder annulus side is secured.
  • This configuration ensures that the reciprocating piston can also be retracted from the extended position if the intermediate piston has already been lowered to such an extent that the intermediate piston bottom area has passed over the connection of the inlet pressure medium line to the cylinder annulus.
  • a short-circuit line between the cylinder annular space and the cylinder pressure space, which is blocked when the end piston is moved against the intermediate piston is also provided with a valve that opens toward the cylinder pressure space, which ensures that leakage oil that enters the annular space, in particular leakage oil that enters the annular space from the inlet pressure medium line , does not lead to an unwanted displacement of the intermediate piston.
  • the actuating plunger associated with the valve inserted into the connecting line in the base of the intermediate piston is suitable as a slide.
  • the solution according to the invention can be implemented in a corresponding manner with a telescopic bushing for the entry pressure medium to the floor of the first stage and into the interior of the final stage.
  • the telescopic cylinder consists of the cylinder 11, the intermediate piston 12 guided therein and the final stage 13, the end piston 13 guided in the intermediate piston 12.
  • the cylinder base is designated 111, the cylinder pressure chamber 112, between the cylinder 11 and the cylinder Intermediate piston 12, the cylinder annulus 112 'is formed.
  • the bottom of the intermediate piston 12 is designated 121, the pressure chamber of the intermediate piston 12 with 122, between the intermediate piston 12 and the end piston 13, the annular space 122 'of the first stage or the intermediate piston 12 is formed.
  • the bottom of the end piston 13 is designated by 131, the interior of the end piston by 132.
  • the pressure chambers 112, 122 of the system are sealed off from the respective annular spaces 112 ', 122' by elastic seals 21, 22 on the circumference of the intermediate piston head 121 or end piston head 131 , the annular spaces 112 ', 122' to the outside then also by elastic seals 23, 24 on the cylinder 11 or on the intermediate piston 12.
  • metallic seal 21 ' On a still provided in the intermediate piston crown 121 metallic seal 21 'will be discussed later.
  • the outlet pressure medium line 114 which acts on the cylinder pressure chamber 112 and is connected to the circumference of the cylinder 11, from a control slide 113, namely a directional valve for the mutual connection of the pressure medium lines 114, 116 to a pressure medium source and with a pressure medium sink
  • the inlet pressure medium line 116 which also extends from the control slide 113, is connected.
  • the position A symbolizes stop
  • the position B extends and the position C retracts.
  • a line 123 which connects the cylinder pressure chamber 112 with the pressure chamber 122 of the intermediate stage 12 and extends through the bottom 121 of the intermediate piston 12, is secured by a non-return valve (125) opening at the transition of the intermediate stage 12 into the extended end position in the direction of the cylinder pressure chamber 112.
  • the implementation 124 ' is sealed against the bottom 131 of the output stage 13 by an elastic seal 26.
  • the inputs of the lines 124 and 124 ⁇ lying on the circumference of the intermediate piston crown 121 are shielded from one another by the seal 21 '. Since this seal 21 'does not have to perform any holding functions, it can be a metallic seal with which the connection 116' of the inlet pressure medium line 116 on the cylinder 11 can be run over without damage. There is then still a constantly open connection 133 between the interior 132 of the output stage 13 and the annular space 122 'of the intermediate stage 12.
  • the collet 129 which runs up against a stop 117 on the cylinder 11, is lowered, so that its stop 129 'acting on the plunger 125' of the closing body 125 of the valve 123 inserted into the line 123 (125) opens the Valve (125) and the continuous connection between the cylinder pressure chamber 112 and the pressure chamber 122 of the intermediate stage 12 is established.
  • valve (126) in the outgoing line from the connecting line between the interior 132 of the output stage 13 and the inlet pressure medium line 16, above the intermediate piston crown 121 into the cylinder annular space 112 'branching branch 124' in the intermediate piston crown 121 is one of the closing body 126 of the valve outgoing, with the valve closed in the pressure chamber 122 of the intermediate piston 12 projecting, axially parallel plunger 126 'is provided.
  • the control slide 113 is moved into position B and pressure medium is first introduced into the cylinder pressure chamber 112 via the extension pressure medium line 114 , a simultaneous overflow of the pressure medium into the pressure chamber 122 of the intermediate stage 12 by the valve located in the connecting line 123 between the cylinder pressure chamber 112 and the pressure chamber 122 of the intermediate stage 12, under the action of the pressure medium present behind it in the cylinder pressure chamber 112, supported by a return spring 125 ⁇ closed valve (125) is prevented, so that initially only the intermediate stage 12 extends.
  • the adjusting ring 129 which runs against the stop 118 on the cylinder 11 and is supported on the intermediate piston crown 121, is lowered, with its plunger 125 ′ extending from the closing body 125 of the valve (125) overlapping attachment 129 ′ the closing body 125 ′ Lowering via the plunger 129 'opens the valve, so that if the supply of pressure medium continues, pressure medium can now flow into the intermediate piston pressure chamber 122, under the action of which the end piston 13 is extended.
  • the extension sequence between intermediate pistons 12 and end pistons 13 is thus clearly defined.
  • the control slide 113 is moved into position C and pressure medium passes through the inlet pressure medium line 116, the connecting line 124 in Intermediate piston crown 121 and the passage 124 'in the interior 132 of the final stage 13, from which it passes through the passage 133 into the annular space 122' of the intermediate stage 12 and causes the intermediate stage 12 to be drawn in.
  • the embodiment according to FIG. 4 ensures that the end piston 13 can also be retracted from the extended position when the intermediate stage 12 is lowered so far that the intermediate piston crown 121 has already run over the connection 116 'of the inlet pressure medium line 116 to the cylinder annulus 112' . Then retracting pressure medium through the branch line 124 adopted still provided in the intermediate piston crown 121 while still opening the check valve 130 provided therein still into the connecting line 124 and from there into the passage 124 'and further into the interior 132 of the output stage 13 and the annular space 122' of the intermediate stage 12 to arrive.
  • the check valve 130 which closes under spring pressure, ensures that the retraction sequence of the end piston 13 - intermediate piston 12 remains guaranteed under normal conditions.
  • a short-circuit line 124 IV which is blocked when the reciprocating piston 13 is lowered against the intermediate piston crown 121, is additionally provided between the cylinder annulus 112 'and the cylinder pressure chamber 112, into which a spring-loaded check valve 133 opening to the cylinder pressure chamber 112 is inserted.
  • This short-circuit line 124 IV enables the breakdown of leakage oil entering the annular space 112 ', such as leakage oil originating in the hydraulic oil line 116, build-up excess pressure to the cylinder pressure space 112, thereby avoiding that the intermediate piston 12 runs in unintentionally.
  • the necessary for the intended retraction of the intermediate piston 12 interruption of the connection between the cylinder annulus 112 'and the cylinder pressure chamber 112 is by the plunger designed as a slide 126' of the lead 124 through the passage 124 'in the interior 131 of the reciprocating piston 13 in the intermediate piston crown 121 inserted, caused by running up of the retracting piston 13 on the plunger 126 'in the closed position valve 126 which, lowered, shuts off the short-circuit line 124 IV .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)

Description

Die Erfindung betrifft einen mehrstufigen hydraulischen Teleskopzylinder entsprechend dem Oberbegriff des Anspruches 1. Ein solcher Teleskopzylinder ist beispielsweise beschrieben in der DE-A-2 253 646.The invention relates to a multi-stage hydraulic telescopic cylinder according to the preamble of claim 1. Such a telescopic cylinder is described for example in DE-A-2 253 646.

Bei dem vorbekannten Teleskopzylinder wird die gewünschte Ausfahrfolge Zwischenstufe - Endstufe dadurch sichergestellt, daß in der Zylinderwandung eine Umgehung vorgesehen wird, die in Ausfahrendlage des Zwischenkolbens über den Zwischenkolbenboden eine Verbindung zwischen dem Zylinderdruckraum und dem Druckraum des Zwischenkolbens herstellt. Auch was die gewünschte Einfahrfolge Endstufe - Zwischenstufe betrifft, muß hierbei eine Bohrung in der Zwischenkolbenwandung überfahren werden. Das Einlaufen in die Umgehung an der Zylinderwandung und das Überfahren der Bohrung in der Zwischenkolbenwandung machen metallische Dichtungen erforderlich, die nicht vollständig abdichten, was zur Folge hat, daß solche Teleskopzylinder in der Haltesituation nicht vollständig lagestabil sind.In the known telescopic cylinder, the desired extension sequence intermediate stage - final stage is ensured in that a bypass is provided in the cylinder wall, which creates a connection between the cylinder pressure chamber and the pressure chamber of the intermediate piston in the extended end position of the intermediate piston via the intermediate piston head. As far as the desired drive-in sequence for the final stage - intermediate stage is concerned, a hole in the intermediate piston wall must be run over. Running into the bypass on the cylinder wall and passing over the bore in the intermediate piston wall make metallic seals necessary, which do not seal completely, with the result that such telescopic cylinders are not completely stable in the holding situation.

Ausgehend vom im vorausgehenden umrissenen Stand der Technik liegt der Erfindung die Aufgabe zugrunde, ein gattungsgemäßes Teleskopiersystem so auszugestalten, daß seine absolute Lagestabilität in der Haltesituation gewährleistet wird.On the basis of the prior art outlined above, the invention is based on the object of designing a generic telescopic system in such a way that its absolute positional stability is ensured in the holding situation.

Die Aufgabe wird mit einem gattungsgemäßen Teleskopzylinder gelöst, der entsprechend dem kennzeichnenden Teil des Anspruches 1 ausgestaltet ist.The object is achieved with a generic telescopic cylinder which is designed in accordance with the characterizing part of claim 1.

Der erfindungsgemäße Teleskopzylinder, der Umgehungen bzw. Bohrungen in den kritischen Bereichen generell vermeidet, gestattet den Einsatz elastischer Dichtungen, sogenannter Weichdichtungen, jedenfalls an den Stellen, an denen eine hundertprozentige Abdichtung Voraussetzung für die absolute Lagestabilität des Zylinders in der Haltesituation ist. Die erfindungsgemäße Lösung baut dann auch kürzer als Umgehungen verwendende Lösungen. Die Lösung ist im übrigen fertigungs-, montage- und wartungsfreundlich sowie verschleißarm.The telescopic cylinder according to the invention, which generally avoids bypasses or bores in the critical areas, permits the use of elastic seals, so-called soft seals, at least at those points where a 100% seal is a prerequisite for the absolute positional stability of the cylinder in the holding situation. The solution according to the invention then also builds shorter solutions than bypasses. The solution is also easy to manufacture, assemble and maintain, as well as being low-wear.

In der DE-A-3 021 633 ist zwar auch schon ein mehrstufiger hydraulischer Teleskopzylinder beschrieben, bei dem die Ausfahrfolge Zwischenstufe - Endstufe über eine Verbindungsleitung im Zwischenkolbenboden sichergestellt wird, wobei in die Verbindungsleitung ein beim Übergang des Zwischenkolbens in die Ausfahrendlage entsperrbares Rückschlagventil eingefügt ist, damit allein wird das Problem der Lagestabilisierung des Teleskopzylinders in der Haltesituation jedoch noch nicht vollständig gelöst, da die auch hier gewünschte Einfahrfolge Endstufe - Zwischenstufe nach wie vor in der Weise bewirkt wird, daß der Boden der Endstufe beim Übergang in die Einfahrendlage der Endstufe eine die Verbindung zum Zylinderringraum herstellende Bohrung in der den Zylinderringraum begrenzenden Wandung der Zwischenstufe überfährt, was im Boden der Endstufe nach wie vor eine nichtleckfreie metallische Dichtung erforderlich macht. Angesprochen ist in der DE-A-3 021 633 dann auch, daß in Zusammenhang mit der Absicherung der Verbindungsleitung zwischen dem Zylinderdruckraum und dem Druckraum der Zwischenstufe durch ein beim Übergang des Zwischenkolbens in die Ausfahr-Endstufe mechanisch aufsteuerbares Rückschlagventil sich eine Anordnung des Rückschlagventils parallel zur Zylinderlängsachse nicht empfiehlt und ein zur Längsachse des Teleskopzylinders geneigte Anordnung des Ventils vorzuziehen ist. Damit sind dann allerdings erhebliche fertigungstechnische Probleme verbunden.In DE-A-3 021 633 a multi-stage hydraulic telescopic cylinder is already described, in which the extension sequence intermediate stage - final stage is ensured via a connecting line in the intermediate piston crown, the connecting line being inserted when the intermediate piston moves into the extended final position Unlockable non-return valve is inserted, so that the problem of stabilizing the position of the telescopic cylinder in the holding situation alone is not yet completely solved, since the desired drive-in sequence for the power amplifier - intermediate stage is still effected in such a way that the bottom of the power amplifier during the transition to the Retraction end position of the output stage passes over a bore that creates the connection to the cylinder annulus in the wall of the intermediate stage bounding the cylinder annulus, which still requires a non-leak-free metallic seal in the bottom of the output stage. DE-A-3 021 633 also addresses the fact that in connection with the protection of the connecting line between the cylinder pressure chamber and the pressure chamber of the intermediate stage, a check valve is arranged in parallel by a check valve which can be mechanically actuated when the intermediate piston moves into the extension output stage to the longitudinal axis of the cylinder is not recommended and an arrangement of the valve inclined to the longitudinal axis of the telescopic cylinder is preferable. However, this then involves considerable manufacturing problems.

Mit der Erfindung wird dann auch eine einwandfreie Absicherung der Verbindungsleitung zwischen dem Zylinderdruckraum und dem Innenraum der Zwischenstufe mittels einer Ventilanordnung parallel zur Längsachse des Teleskopzylinders realisiert. Zweckmäßigerweise sind hierbei sowohl dem Schließkörper des die Verbindungsleitung zwischen dem Zylinderdruckraum und dem Innenraum des Zwischenkolbens absichernden Ventils als auch dem dem Zwischenkolbenboden zugeordneten sogenannten Stellring Rückstellfedern zugeordnet.With the invention, a perfect protection of the connecting line between the cylinder pressure chamber and the interior of the intermediate stage is then realized by means of a valve arrangement parallel to the longitudinal axis of the telescopic cylinder. In this case, both the closing body of the valve securing the connecting line between the cylinder pressure chamber and the interior of the intermediate piston are expedient also associated with the so-called adjusting ring return springs assigned to the intermediate piston crown.

In Ausgestaltung der Erfindung geht von der von der den Innenraum des Endkolbens über die vom Zwischenkolbenboden ausgehende Durchführung beaufschlagenden Verbindungsleitung im Zwischenkolbenboden abgehenden, zum Zylinderringraum oberhalb des Zwischenkolbenbodens führenden, eine das Ventil in der Zweigleitung umgehende, in die Verbindungsleitung mündende Stichleitung aus, die durch ein federbelastetes, von zylinderringraumseitig anstehendem Druckmitteldruck aufsteuerbares Ventil abgesichert ist. Diese Ausgestaltung stellt sicher, daß sich der Hubkolben auch dann aus der Ausfahrstellung einziehen läßt, wenn der Zwischenkolben vorweg bereits soweit abgesenkt ist, daß der Zwischenkolbenbodenbereich den Anschluß der Einfahrdruckmittelleitung an den Zylinderringraum überfahren hat.In an embodiment of the invention, a branch line that bypasses the valve in the branch line and leads into the connecting line, starting from the connecting line in the intermediate piston bottom that leads to the cylinder annular space above the intermediate piston bottom, leading from the interior of the end piston via the bushing leading from the intermediate piston bottom, through a connecting line spring-loaded valve which can be actuated by pressure medium pressure on the cylinder annulus side is secured. This configuration ensures that the reciprocating piston can also be retracted from the extended position if the intermediate piston has already been lowered to such an extent that the intermediate piston bottom area has passed over the connection of the inlet pressure medium line to the cylinder annulus.

In weiterer Ausgestaltung ist dann auch noch eine bei gegen den Zwischenkolben verfahrenem Endkolben gesperrte Kurzschlußleitung zwischen dem Zylinderringraum und dem Zylinderdruckraum mit einem zum Zylinderdruckraum hin öffnenden Ventil vorgesehen, der sicherstellt, daß in den Ringraum gelangendes Lecköl, insbesondere aus der Einfahrdruckmittelleitung in den Ringraum gelangendes Lecköl, nicht zu einer ungewollten Verlagerung des Zwischenkolbens führt. Für die Sperrung der Kurzschlußleitung bei gegen den Zwischenkolbendoden abgesenktem Endkolben bietet sich der dem in die Verbindungsleitung im Boden des Zwischenkolbens eingefügten Ventil zugeordnete Betätigungsstößel als Schieber ausgebildet an.In a further embodiment, a short-circuit line between the cylinder annular space and the cylinder pressure space, which is blocked when the end piston is moved against the intermediate piston, is also provided with a valve that opens toward the cylinder pressure space, which ensures that leakage oil that enters the annular space, in particular leakage oil that enters the annular space from the inlet pressure medium line , does not lead to an unwanted displacement of the intermediate piston. To block the short-circuit line when the end piston is lowered against the intermediate piston end, the actuating plunger associated with the valve inserted into the connecting line in the base of the intermediate piston is suitable as a slide.

Bei Teleskopzylindern mit mehr als zwei Stufen, kann die erfindungsgemäße Lösung sinngemäß mit einer dementsprechend ausgelegten teleskopierbaren Durchführung für das Einfahrdruckmittel zum Boden der ersten Stufe in den Innenraum der Endstufe realisiert werden.In the case of telescopic cylinders with more than two stages, the solution according to the invention can be implemented in a corresponding manner with a telescopic bushing for the entry pressure medium to the floor of the first stage and into the interior of the final stage.

In der Zeichnung ist die Erfindung an Hand von Ausführungsbeispielen weitergehend erläutert. Es zeigen:

  • Fig. 1 einen zweistufigen Teleskopzylinder, ausgefahren,
  • Fig. 2 den Teleskopzylinder in Fig. 1, die Zwischenstufe ausgefahren, die End stufe eingefahren,
  • Fig. 3 den Teleskopzylinder in den Figuren 1 und 2 vollständig eingefahren,
  • Fig. 4 eine Ausgestaltung des Teleskopzylinders nach den Figuren 1 bis 3, ausgefahren,
  • Fig. 5 eine weitergehende Ausgestaltung des Teleskopzylinders nach Fig. 4, aus gefahren.
In the drawing, the invention is further explained using exemplary embodiments. Show it:
  • 1 is a two-stage telescopic cylinder, extended,
  • 2 the telescopic cylinder in FIG. 1, the intermediate stage extended, the final stage retracted,
  • 3 fully retracted the telescopic cylinder in Figures 1 and 2,
  • 4 shows an embodiment of the telescopic cylinder according to FIGS. 1 to 3, extended,
  • Fig. 5 is a further embodiment of the telescopic cylinder of FIG. 4, driven out.

Der Teleskopzylinder besteht aus dem Zylinder 11, dem darin geführten Zwischenkolben 12 und der im Zwischenkolben 12 geführten Endstufe, dem Endkolben 13. Der Zylinderboden ist mit 111 bezeichnet, der Zylinderdruckraum mit 112, zwischen dem Zylinder 11 und dem Zwischenkolben 12 ist der Zylinderringraum 112′ ausgebildet. Der Boden des Zwischenkolbens 12 ist mit 121 bezeichnet, der Druckraum des Zwischenkolbens 12 mit 122, zwischen dem Zwischenkolben 12 und dem Endkolben 13 ist der Ringraum 122′ der ersten Stufe bzw. des Zwischenkolbens 12 ausgebildet. Der Boden des Endkolbens 13 ist mit 131 bezeichnet, der Innenraum des Endkolbens mit 132. Die Druckräume 112, 122 des Systems sind gegenüber den jeweiligen Ringräumen 112′, 122′ durch elastische Dichtungen 21, 22 am Umfang des Zwischenkolbenbodens 121 bzw. Endkolbenbodens 131 abgedichtet, die Ringräume 112′, 122′ nach außen dann auch durch elastische Dichtungen 23, 24 am Zylinder 11 bzw. am Zwischenkolben 12. Auf eine noch im Zwischenkolbenboden 121 vorgesehene metallische Dichtung 21′ wird später eingegangen.The telescopic cylinder consists of the cylinder 11, the intermediate piston 12 guided therein and the final stage 13, the end piston 13 guided in the intermediate piston 12. The cylinder base is designated 111, the cylinder pressure chamber 112, between the cylinder 11 and the cylinder Intermediate piston 12, the cylinder annulus 112 'is formed. The bottom of the intermediate piston 12 is designated 121, the pressure chamber of the intermediate piston 12 with 122, between the intermediate piston 12 and the end piston 13, the annular space 122 'of the first stage or the intermediate piston 12 is formed. The bottom of the end piston 13 is designated by 131, the interior of the end piston by 132. The pressure chambers 112, 122 of the system are sealed off from the respective annular spaces 112 ', 122' by elastic seals 21, 22 on the circumference of the intermediate piston head 121 or end piston head 131 , the annular spaces 112 ', 122' to the outside then also by elastic seals 23, 24 on the cylinder 11 or on the intermediate piston 12. On a still provided in the intermediate piston crown 121 metallic seal 21 'will be discussed later.

Am Boden 111 des Zylinders 11 ist die von einem Steuerschieber 113, nämlich einem Wegeventil zur wechselseitigen Verbindung der Druckmittelleitungen 114, 116 mit einer Druckmittelquelle und mit einer Druckmittelsenke, ausgehende, den Zylinderdruckraum 112 beaufschlagende Ausfahrdruckmittelleitung 114 angeschlossen, am Umfang des Zylinders 11, und zwar im Bereich der Ausfahrendlage des Zwischenkolbenbodens 121 ist die ebenfalls vom Steuerschieber 113 ausgehende Einfahrdruckmittelleitung 116 angeschlossen. Von den drei möglichen Stellungen A, B, C des Steuerschiebers 113 symbolisiert die Stellung A Halt, die Stellung B Ausfahren und die Stellung C Einfahren. Wie aus den Schaltbildern ersichtlich ist, wird bei der Druckmittelbeaufschlagung der Ausfahrdruckmittelleitung 114 (Stellung B des Steuerschiebers 113) die Verbindung der Einfahrdruckmittelleitung 116 zum Tank freigegeben und bei der Druckmittelbeaufschlagung der Einfahrdruckmittelleitung 116 (Stellung C des Steuerschiebers 113) die Verbindung der Ausfahrdruckmittelleitung 114 zum Tank.At the bottom 111 of the cylinder 11, the outlet pressure medium line 114, which acts on the cylinder pressure chamber 112 and is connected to the circumference of the cylinder 11, from a control slide 113, namely a directional valve for the mutual connection of the pressure medium lines 114, 116 to a pressure medium source and with a pressure medium sink In the area of the extended end position of the intermediate piston crown 121, the inlet pressure medium line 116, which also extends from the control slide 113, is connected. Of the three possible positions A, B, C of the spool 113, the position A symbolizes stop, the position B extends and the position C retracts. As can be seen from the circuit diagrams, when the pressure medium line is applied to the exit pressure medium line 114 (position B of the control slide 113), the connection of the entry pressure medium line 116 to the tank is released, and when the pressure medium is applied to the entry pressure medium line 116 (position C of the control slide 113) the connection of the extension pressure medium line 114 to the tank is released .

Durch den Boden 121 des Zwischenkolbens 12 erstreckt sich zum einen eine den Zylinderdruckraum 112 mit dem Druckraum 122 der Zwischenstufe 12 verbindende, durch ein beim Übergang der Zwischenstufe 12 in die Ausfahrendlage in Richtung auf den Zylinderdruckraum 112 öffnendes Rückschlagventil (125) abgesicherte Leitung 123. Zum andern verläuft im Zwischenkolbenboden 121 eine den Innenraum 132 des Endkolbens 13 über eine vom Zwischenkolbenboden 121 ausgehende, sich durch den Endkolbenboden 131 erstreckende Durchführung 124′ mit der Einfahrdruckmittelleitung 116 in der Ausfahrendlage des Zwischenkolbens 12 verbindende Leitung 124, von der eine oberhalb des Zwischenkolbenbodens 121 in den Ringraum 112′ mündende, durch ein gegen Federdruck (126˝) beim Übergang des Endkolbens 13 in die Einfahrendlage öffnendes Ventil 126 abgesicherte Leitung 124˝ abzweigt.A line 123, which connects the cylinder pressure chamber 112 with the pressure chamber 122 of the intermediate stage 12 and extends through the bottom 121 of the intermediate piston 12, is secured by a non-return valve (125) opening at the transition of the intermediate stage 12 into the extended end position in the direction of the cylinder pressure chamber 112. Zum another runs in the intermediate piston crown 121, an interior 132 of the end piston 13 via a passage 124 'extending from the intermediate piston crown 121 and extending through the end piston crown 131' with the inlet pressure medium line 116 in the extended end position of the intermediate piston 12, connecting line 124, one above the intermediate piston crown 121 in the annular space 112 'opening, branched by a valve 126' branched off by a valve 126 opening against the spring pressure (126˝) at the transition of the end piston 13 into the retracted end position.

Die Durchführung 124′ ist gegenüber dem Boden 131 der Endstufe 13 durch eine elastische Dichtung 26 abgedichtet. Die am Umfang des Zwischenkolbenbodens 121 liegenden Eingänge der Leitungen 124 und 124˝ sind gegeneinander durch die Dichtung 21′ abgeschirmt. Da diese Dichtung 21′ keine Haltefunktionen erfüllen muß, kann es sich dabei um eine metallische Dichtung handeln, mit der sich der Anschluß 116′ der Einfahrdruckmittelleitung 116 am Zylinder 11 unbeschadet überfahren läßt. Es besteht dann noch eine ständig offene Verbindung 133 zwischen dem Innenraum 132 der Endstufe 13 und dem Ringraum 122′ der Zwischenstufe 12.The implementation 124 'is sealed against the bottom 131 of the output stage 13 by an elastic seal 26. The inputs of the lines 124 and 124˝ lying on the circumference of the intermediate piston crown 121 are shielded from one another by the seal 21 '. Since this seal 21 'does not have to perform any holding functions, it can be a metallic seal with which the connection 116' of the inlet pressure medium line 116 on the cylinder 11 can be run over without damage. There is then still a constantly open connection 133 between the interior 132 of the output stage 13 and the annular space 122 'of the intermediate stage 12.

Für die Betätigung des in die Verbindungsleitung 123 zwischen Zylinderdruckraum 112 und Zwischenkolbendruckraum 122 eingefügten Rückschlagventils (125) ist ein sich in einer Ringnut 128 am Umfang des Zwischenkolbenbodens 121 mit achsialem Spiel führender, unter der Einwirkung einer Feder 129˝ angehobener Stellring 129 vorgesehen, der mit einem in einen Rücksprung 128′ in der Ringnut 128 oberhalb des Ventils (125) hineinragenden Ansatz 129′ versehen ist, der sich über einen vom Schließkörper 125 des Ventils (125) ausgehenden, in den Rücksprung 128′ hineinragenden Stößel 125′ mit achsparallelem Verlauf erstreckt. Beim Übergang des Zwischenkolbens 12 in die Ausfahrendlage wird der gegen einen Anschlag 117 am Zylinder 11 auflaufende Stellring 129 abgesenkt, wodurch über seinen auf den Stößel 125′ des Schließkörpers 125 des in die Leitung 123 eingefügten Ventils (125) einwirkenden Anschlag 129′ die Öffnung des Ventils (125) bewirkt und die durchgängige Verbindung zwischen dem Zylinderdruckraum 112 und dem Druckraum 122 der Zwischenstufe 12 hergestellt wird.For the actuation of the check valve (125) inserted into the connecting line 123 between the cylinder pressure chamber 112 and the intermediate piston pressure chamber 122 in an annular groove 128 on the circumference of the intermediate piston crown 121 with axial play leading, under the action of a spring 129˝ raised collar 129 provided with a projection 128 'in a recess 128' in the annular groove 128 above the valve (125) provided approach 129 ' is, which extends over a from the closing body 125 of the valve (125), in the recess 128 'protruding plunger 125' with an axially parallel course. At the transition of the intermediate piston 12 into the extended end position, the collet 129, which runs up against a stop 117 on the cylinder 11, is lowered, so that its stop 129 'acting on the plunger 125' of the closing body 125 of the valve 123 inserted into the line 123 (125) opens the Valve (125) and the continuous connection between the cylinder pressure chamber 112 and the pressure chamber 122 of the intermediate stage 12 is established.

Für die Betätigung des Ventils (126) in der von der die Verbindung zwischen dem Innenraum 132 der Endstufe 13 und der Einfahrdruckmittelleitung 16 herstellenden Leitung 124 abgehenden, oberhalb des Zwischenkolbenbodens 121 in den Zylinderringraum 112′ mündenden Zweigleitung 124˝ im Zwischenkolbenboden 121 ist ein vom Schließkörper 126 des Ventils ausgehender, bei geschlossenem Ventil in den Druckraum 122 des Zwischenkolbens 12 vorspringender, achsparallel verlaufender Stößel 126′ vorgesehen. Beim Übergang der Endstufe 13 in die Einfahrendlage läuft der Boden 131 der Endstufe gegen diesen Stößel 126′ auf und senkt ihn gegen den Druck der den Schließkörper 126 des Ventils hinterfangenden Rückstellfeder 126˝ ab, woraus die Öffnung des Ventils (126) resultiert und die Verbindung zwischen dem Zylinderringraum 112′ und der Einfahrdruckmittelleitung 116 bei in Ausfahrendlage befindlichem Zwischenkolben 12 hergestellt ist.For the actuation of the valve (126) in the outgoing line from the connecting line between the interior 132 of the output stage 13 and the inlet pressure medium line 16, above the intermediate piston crown 121 into the cylinder annular space 112 'branching branch 124' in the intermediate piston crown 121 is one of the closing body 126 of the valve outgoing, with the valve closed in the pressure chamber 122 of the intermediate piston 12 projecting, axially parallel plunger 126 'is provided. At the transition of the final stage 13 into the retracted position, the bottom 131 of the final stage runs against this plunger 126 'and lowers it against the pressure of the return spring 126˝ trapping the closing body 126 of the valve, resulting in the opening of the valve (126) and the connection between the Cylinder annulus 112 'and the inlet pressure medium line 116 is made with the intermediate piston 12 in the extended position.

Zum Ausfahren des Teleskopzylinders, also zum in den Figuren 1 bis 3 in der Abfolge 3 - 2 - 1 erfolgenden Verschieben der Teleskopglieder 12 und 13, wird der Steuerschieber 113 in die Position B überführt und Druckmittel über die Ausfahrdruckmittelleitung 114 zunächst in den Zylinderdruckraum 112 eingeleitet, wobei ein gleichzeitiges Überströmen des Druckmittels in den Druckraum 122 der Zwischenstufe 12 durch das in der Verbindungsleitung 123 zwischen Zylinderdruckraum 112 und Druckraum 122 der Zwischenstufe 12 befindliche, unter der Einwirkung des hinter ihm im Zylinderdruckraum 112 anstehenden Druckmittels unterstützt durch eine Rückstellfeder 125˝ geschlossene Ventil (125) unterbunden wird, so daß zunächst ausschließlich die Zwischenstufe 12 ausfährt. Beim Übergang der Zwischenstufe 12 in die Ausfahrendlage wird der gegen den Anschlag 118 am Zylinder 11 auflaufende, am Zwischenkolbenboden 121 gelagerte Stellring 129 abgesenkt, wobei sein den vom Schließkörper 125 des Ventils (125) ausgehenden Stößel 125′ übergreifender Ansatz 129′ den Schließkörper 125′ über den Stößel 129′ absenkend das Ventil öffnet, so daß bei anhaltender druckmittelzufuhr nunmehr Druckmittel in den Zwischenkolbendruckraum 122 einzuströmen vermag, unter dessen Einwirkung der Endkolben 13 ausgefahren wird. Damit ist die Ausfahrfolge Zwischenkolben 12 - Endkolben 13 eindeutig festgelegt. Das beim Ausfahren der Zwischenstufe 12 aus dem Zylinderringraum 112′ zu verdrängende Druckmittel strömt bei noch in Einfahrendstellung befindlicher Endstufe 13 geöffnetem Ventil (126) durch die Zweigleitung 124˝ und die Verbindungsleitung 124 im Zwischenkolbenboden 121 in die beim Ausfahrvorgang zum Tank hin durchgängigen Einfahrdruckmittelleitung 116 ab.To extend the telescopic cylinder, i.e. to move the telescopic members 12 and 13 in the sequence 3 - 2 - 1 in FIGS. 1 to 3, the control slide 113 is moved into position B and pressure medium is first introduced into the cylinder pressure chamber 112 via the extension pressure medium line 114 , a simultaneous overflow of the pressure medium into the pressure chamber 122 of the intermediate stage 12 by the valve located in the connecting line 123 between the cylinder pressure chamber 112 and the pressure chamber 122 of the intermediate stage 12, under the action of the pressure medium present behind it in the cylinder pressure chamber 112, supported by a return spring 125˝ closed valve (125) is prevented, so that initially only the intermediate stage 12 extends. At the transition of the intermediate stage 12 into the extended end position, the adjusting ring 129, which runs against the stop 118 on the cylinder 11 and is supported on the intermediate piston crown 121, is lowered, with its plunger 125 ′ extending from the closing body 125 of the valve (125) overlapping attachment 129 ′ the closing body 125 ′ Lowering via the plunger 129 'opens the valve, so that if the supply of pressure medium continues, pressure medium can now flow into the intermediate piston pressure chamber 122, under the action of which the end piston 13 is extended. The extension sequence between intermediate pistons 12 and end pistons 13 is thus clearly defined. The pressure medium to be displaced when the intermediate stage 12 is extended from the cylinder annulus 112 'flows while still in the retracted position located final stage 13 open valve (126) through the branch line 124˝ and the connecting line 124 in the intermediate piston head 121 into the inlet pressure medium line 116 which is continuous to the tank during the extension process.

Zum Einfahren des Teleskopzylinders, also zum in den Figuren 1 bis 3 in der Abfolge 1 - 2 - 3 erfolgenden Verschieben der Teleskopglieder 12 und 13, wird der Steuerschieber 113 in die Position C überführt und Druckmittel gelangt über die Einfahrdruckmittelleitung 116, die Verbindungsleitung 124 im Zwischenkolbenboden 121 und die Durchführung 124′ in den Innenraum 132 der Endstufe 13, aus dem es durch den Durchgang 133 in den Ringraum 122′ der Zwischenstufe 12 gelangt und das Einziehen der Zwischenstufe 12 bewirkt. Die gleichzeitige Beaufschlagung des Zylinderringraums 112′ mit Einfahrdruckmittel ist unterbunden einerseits durch die Unterbrechung (126) der Verbindung 124˝ im Zwischenkolbenboden 121 und andererseits durch die Dichtung 21′ am Umfang des Zwischenkolbenbodens 121. Aus dem Druckraum 122 des Zwischenkolbens 12 verdrängtes Druckmittel strömt über die Leitung 123 im Zwischenkolbenboden 121 bei unter der Einwirkung vor ihm anstehenden Druckmitteldrucks öffnendem Ventil (125) in den Zylinderdruckraum 112 über und von dort durch die während des Einfahrvorganges zum Tank hin durchgängige Ausfahrdruckmittelleitung 114 ab. Beim Übergang des Endkolbens 13 in die Einfahrendlage wird der die Zweigleitung 124˝ zum Zylinderringraum 112′ oberhalb des Zwischenkolbenbodens 121 im Zwischenkolbenboden 121 absperrende Schließkörper 126 durch das Absenken des von ihm ausgehenden, in Schließlage des Schließkörpers 126 über den Zwischenkolbenboden 121 vorspringenden Stößels 126′ beim Auflaufen des Endkolbenbodens 131 auf den Zwischenkolbenboden 121 aus seiner Schließlage entfernt und das weiterhin durch die Einfahrdruckmittelleitung 116 eingespeiste Druckmittel vermag zunächst einmal durch die Zweigleitung 124˝ in den Zylinderdruckraum 112′ oberhalb des Zwischenkolbenbodens 121 zu strömen, womit das Einfahren der Zwischenstufe 12 im Anschluß an das Einfahren der Endstufe 13 eingeleitet wird. Nach dem Überfahren des Anschlusses 116′ der Einfahrdruckmittelleitung 116 am Zylinder 11 wird der Zylinderringraum 112′ sodann unmittelbar beaufschlagt. Sich im Zylinderdruckraum 112 befindliches Druckmittel strömt weiterhin durch die Ausfahrdruckmittelleitung 114 zum Tank hin ab.To retract the telescopic cylinder, that is to say to move the telescopic members 12 and 13 in the sequence 1 - 2 - 3 in FIGS. 1 to 3, the control slide 113 is moved into position C and pressure medium passes through the inlet pressure medium line 116, the connecting line 124 in Intermediate piston crown 121 and the passage 124 'in the interior 132 of the final stage 13, from which it passes through the passage 133 into the annular space 122' of the intermediate stage 12 and causes the intermediate stage 12 to be drawn in. The simultaneous loading of the cylinder annulus 112 'with the inlet pressure medium is prevented on the one hand by the interruption (126) of the connection 124' in the intermediate piston crown 121 and on the other hand by the seal 21 'on the circumference of the intermediate piston crown 121. Pressure medium displaced from the pressure chamber 122 of the intermediate piston 12 flows over the Line 123 in the intermediate piston crown 121 with the valve (125) opening under the action of the pressure medium pressure in front of it into the cylinder pressure chamber 112 and from there through the outlet pressure medium line 114 which is continuous to the tank during the retraction process. At the transition of the end piston 13 into the retracted end position, the branch line 124˝ to the cylinder annulus 112 'above the intermediate piston crown 121 in the intermediate piston crown 121 blocking closing body 126 by lowering the outgoing from it, in the closed position of the closing body 126 the intermediate piston crown 121 protruding plunger 126 'when the end piston crown 131 runs onto the intermediate piston crown 121 removed from its closed position and the pressure medium fed further through the inlet pressure medium line 116 can initially flow through the branch line 124˝ into the cylinder pressure chamber 112' above the intermediate piston crown 121, with which the retraction of the intermediate stage 12 is initiated after the retraction of the final stage 13. After driving over the connection 116 'of the inlet pressure medium line 116 on the cylinder 11, the cylinder annulus 112' is then immediately acted upon. Pressure medium located in the cylinder pressure chamber 112 continues to flow out through the extension pressure medium line 114 to the tank.

Die Ausführungsform nach Fig. 4 stellt sicher, daß sich der Endkolben 13 auch dann aus der Ausfahrstellung einziehen läßt, wenn die Zwischenstufe 12 voreilend soweit abgesenkt ist, daß der Zwischenkolbenboden 121 bereits den Anschluß 116′ der Einfahrdruckmittelleitung 116 an den Zylinderringraum 112′ überfahren hat. Dann vermag Einfahrdruckmittel durch die im Zwischenkolbenboden 121 noch vorgesehene Stichleitung 124‴ unter Öffnung des darin vorgesehenen Rückschlagventils 130 immer noch in die Verbindungsleitung 124 und von dort in die Durchführung 124′ und weitergehend in den Innenraum 132 der Endstufe 13 sowie den Ringraum 122′ der Zwischenstufe 12 zu gelangen. Das unter Federdruck schließende Rückschlagventil 130 stellt hierbei sicher, daß die Einfahrfolge Endkolben 13 - Zwischenkolben 12 unter Normalbedingungen gewährleistet bleibt.The embodiment according to FIG. 4 ensures that the end piston 13 can also be retracted from the extended position when the intermediate stage 12 is lowered so far that the intermediate piston crown 121 has already run over the connection 116 'of the inlet pressure medium line 116 to the cylinder annulus 112' . Then retracting pressure medium through the branch line 124 vorgesehen still provided in the intermediate piston crown 121 while still opening the check valve 130 provided therein still into the connecting line 124 and from there into the passage 124 'and further into the interior 132 of the output stage 13 and the annular space 122' of the intermediate stage 12 to arrive. The check valve 130, which closes under spring pressure, ensures that the retraction sequence of the end piston 13 - intermediate piston 12 remains guaranteed under normal conditions.

Bei der Ausführungsform nach Fig. 5 ist ergänzend eine bei gegen den Zwischenkolbenboden 121 abgesenktem Hubkolben 13 gesperrte Kurzschlußleitung 124IV zwischen dem Zylinderringraum 112′ und dem Zylinderdruckraum 112 vorgesehen, in die ein federbelastetes, zum Zylinderdruckraum 112 öffnendes Rückschlagventil 133 eingefügt ist. Diese Kurzschlußleitung 124IV ermöglicht den Abbau von sich durch in den Ringraum 112′ gelangendes Lecköl, etwa vom in der Einfahrdruckmittelleitung 116 anstehenden Hydrauliköl herrührendem Lecköl, aufbauendem Überdruck zum Zylinderdruckraum 112 hin, womit vermieden wird, daß der Zwischenkolben 12 ungewollt einfährt. Die für das gewollte Einfahren des Zwischenkolbens 12 erforderliche Unterbrechung der Verbindung zwischen dem Zylinderringraum 112′ und dem Zylinderdruckraum 112 wird durch den als Schieber ausgebildeten Stößel 126′ des in die über die Durchführung 124′ in den Innenraum 131 des Hubkolbens 13 führende Verbindungsleitung 124 im Zwischenkolbenboden 121 eingefügten, durch Auflaufen des einfahrenden Hubkolbens 13 auf den Stößel 126′ in Schließstellung überführten Ventils 126 bewirkt, der abgesenkt die Kurzschlußleitung 124IV absperrt.In the embodiment according to FIG. 5, a short-circuit line 124 IV, which is blocked when the reciprocating piston 13 is lowered against the intermediate piston crown 121, is additionally provided between the cylinder annulus 112 'and the cylinder pressure chamber 112, into which a spring-loaded check valve 133 opening to the cylinder pressure chamber 112 is inserted. This short-circuit line 124 IV enables the breakdown of leakage oil entering the annular space 112 ', such as leakage oil originating in the hydraulic oil line 116, build-up excess pressure to the cylinder pressure space 112, thereby avoiding that the intermediate piston 12 runs in unintentionally. The necessary for the intended retraction of the intermediate piston 12 interruption of the connection between the cylinder annulus 112 'and the cylinder pressure chamber 112 is by the plunger designed as a slide 126' of the lead 124 through the passage 124 'in the interior 131 of the reciprocating piston 13 in the intermediate piston crown 121 inserted, caused by running up of the retracting piston 13 on the plunger 126 'in the closed position valve 126 which, lowered, shuts off the short-circuit line 124 IV .

Claims (7)

1. Hydraulic telescopic cylinder, having a cylinder (11), at least one hollow intermediate piston (12), which is displaceable therein, and a hollow end piston (13), which is displaceable in the end intermediate piston, and having annular chambers (112′, 122′) between the individual telescopic members, having a pressure medium discharge pipe (114), which discharges into the cylinder (11) at the base (111), and having a pressure medium inlet pipe (116), which communicates with the cylinder (11) and fills the annular chamber (112′) of the cylinder (11) when the intermediate piston (12) is wholly or partially retracted, as well as when the intermediate piston (12) is extended and the end piston (13) is retracted, having a first connecting pipe (123) between pressure chamber (112) of the cylinder (11) and pressure chamber (122) of the intermediate piston (12) in the intermediate piston base (121), and having a second connecting pipe (124) in the intermediate piston base (121), which pipe short-circuits the interior (132) of the hollow end piston (13) in the final extended position of the intermediate piston (12) by means of the pressure medium inlet pipe (116) and continues into the interior (132) of the end piston (13) via a passage (124′), which extends from the intermediate piston base (121), having a connection (133) between annular chamber (122′) of the intermediate piston (12) and interior (132) of the end piston (13), as well as having a directional valve (113) for the alternate connection of the pressure medium pipes (114, 116) to a source of pressure medium and to a trough of pressure medium, characterised in that
a) a valve is introduced into the connecting pipe (123) in the intermediate piston base (121) between the cylinder pressure chamber (112) and the pressure chamber (122) of the intermediate piston (12), which valve has a closing member (125) provided with a stem (125′), which extends in the direction of extension in an axis-parallel manner; when the valve is in its closed position, the stem (125′) protrudes into a socket (128′), which extends from an annular groove (128) on the periphery of the intermediate piston base (121); and an adjusting ring (129) is guided in the annular groove (128) with axial clearance, which adjusting ring abuts against a stop member (117) on the cylinder (11) as it passes the intermediate piston base (121) in the final extended position, and from which adjusting ring an extension member (129′) extends, which extension member extends into the socket (128′) in the annular groove (128) via the stem (125′);
b) and a branch pipe (124˝) extends from the connecting pipe (124), which leads to the interior (132) of the end piston (13) via the passage (124′), in the base (121) of the intermediate piston (12), which branch pipe discharges into the annular chamber (112′) of the cylinder above the intermediate piston base (121); a valve (126) is introduced into said branch pipe, a stem (126′) extending from the closing member (126) of said valve which closes under spring pressure, which stem extends in the direction of extension in an axis-parallel manner and protrudes into the pressure chamber (122) of the intermediate piston (12) via the intermediate piston base (121) when the valve is in its closed position.
2. Telescopic cylinder according to claim 1, characterised in that the closing member (125) of the valve, which is introduced into the connecting pipe (123) between the pressure chamber (112) of the cylinder and the interior (122) of the intermediate piston (12), is gripped behind by a return spring (125˝).
3. Telescopic cylinder according to claim 1 or claim 2, characterised in that the adjusting ring (129), which is associated with the intermediate piston base (121), is gripped behind by a return spring (129˝).
4. Telescopic cylinder according to one of claims 1 to 3, characterised in that a tap line (124‴) extends from the branch pipe (124˝), which starts from the connecting pipe (124) in the intermediate piston base (121), which connecting pipe leads to the interior (132) of the end piston (13), and said branch pipe leads to the annular chamber (112′) of the cylinder above the intermediate piston base (121), said tap line passing around the valve (126) in the branch pipe (124˝) and discharging into the connecting pipe (124), which tap line is protected by means of a spring-loaded valve (130), which is actuatable by means of the pressure medium pressure existing at the end facing the annular chamber of the cylinder.
5. Telescopic cylinder according to one of claims 1 to 4, characterised in that a short-circuit line (124IV), which is blocked when the end piston (13) is displaced towards the intermediate piston base (121), extends to the pressure chamber (112) of the cylinder from the branch pipe (124˝) in the intermediate piston base (121), said branch pipe leading to the annular chamber (112′) of the cylinder, which short-circuit line is protected by means of a spring-loaded valve (133), which is actuatable by means of the pressure medium pressure existing at the end facing the annular chamber of the cylinder.
6. Telescopic cylinder according to claim 5, characterised in that the actuating rod (126′) associated with the valve (126), which is introduced into the connecting pipe (124) in the base (121) of the intermediate piston (12), which pipe leads to the interior (132) of the end piston (13) via the passage (124′), is adapted as a slide member which blocks the short-circuit line (124IV).
7. Telescopic cylinder according to one of claims 1 to 6, having more than two stages, characterised by a telescopable passage for the retractable pressure medium, which passage starts from the base of the first stage and extends into the interior of the final stage.
EP89112435A 1988-07-08 1989-07-07 Multiple-stage hydraulic telescopic actuator with control of the extension or retraction of the telescopic parts in an imposed order Expired - Lifetime EP0350053B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3823225A DE3823225A1 (en) 1988-07-08 1988-07-08 Multi-stage hydraulic telescopic cylinder with positive control for the extension and retraction sequence of the telescopic members
DE3823225 1988-07-08

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EP0350053A1 EP0350053A1 (en) 1990-01-10
EP0350053B1 true EP0350053B1 (en) 1992-06-10

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EP89112435A Expired - Lifetime EP0350053B1 (en) 1988-07-08 1989-07-07 Multiple-stage hydraulic telescopic actuator with control of the extension or retraction of the telescopic parts in an imposed order

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7069728B2 (en) 2003-07-29 2006-07-04 Pratt & Whitney Canada Corp. Multi-position BOV actuator

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4021280C2 (en) * 1990-07-05 1994-08-25 Montan Hydraulik Gmbh & Co Kg Two-stage hydraulic telescopic cylinder with positive control for the extension and retraction sequence of the telescopic links
DE4219906C2 (en) * 1992-06-17 1995-04-20 Schema Hydraulik Gmbh Hydraulic cylinder with an axially movable piston
CN104033443A (en) * 2014-05-20 2014-09-10 苏州好特斯模具有限公司 Split type double-layer air cylinder
CN104358738B (en) * 2014-10-14 2017-03-01 北京工业大学 A kind of multi-stage cylinder of sequentially-operating
US20210360879A1 (en) * 2018-04-06 2021-11-25 Tmk Energiakoura Oy Hydraulic actuator, working device, and energy-wood grapple

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1030717A (en) * 1963-09-17 1966-05-25 Decca Ltd Improvements in or relating to two-stage fluid pressure operated piston and cylinderassemblies
DE1976924U (en) * 1965-02-17 1968-01-11 Toussaint & Hess Gmbh HYDRAULIC PISTON DRIVE WITH TELESCOPIC PISTON.
FR2129936B1 (en) * 1971-03-17 1976-02-06 Benalu Fr
DE2253646C3 (en) * 1972-11-02 1980-08-21 Montan-Hydraulik Gmbh & Co Kg, 4755 Holzwickede Multi-stage hydraulic telescopic cylinder
FR2253160B1 (en) * 1973-12-03 1977-06-24 Poclain Sa
DE2641216C2 (en) * 1976-09-14 1982-09-02 Montan - Hydraulik GmbH & Co KG, 4755 Holzwickede Multi-stage hydraulic telescopic cylinder
DE2648608C3 (en) * 1976-10-27 1979-11-29 Walter Hunger Kg, 8770 Lohr Control device for a differential cylinder
DE2719848C2 (en) * 1977-05-04 1985-09-26 Montanhydraulik Gmbh & Co Kg, 4755 Holzwickede Multi-stage hydraulic telescopic cylinder
DE2816175A1 (en) * 1978-04-14 1979-10-18 Montan Hydraulik Gmbh & Co Kg Multistage hydraulic telescopic cylinder - has non-return valve and by=pass in hydraulic system ensuring stable actuation of successive pistons
JPS5578809A (en) * 1978-12-06 1980-06-13 Yunitsuku:Kk Three-stage cylinder device
DE2900015A1 (en) * 1979-01-02 1980-07-10 Benteler Werke Ag Constant-rate telescopic cylinder spring device - has valve plug coupled to plunger in chamber connected to outer piston chamber
DE3021633A1 (en) * 1980-06-09 1981-12-17 Schütt, Friedrich, 4755 Holzwickede Multistage telescopic hydraulic ram - has control members in crowns of individual hollow pistons
JPS5797903A (en) * 1980-12-06 1982-06-17 Yunitsuku:Kk Double-acting cylinder
JPS57184709A (en) * 1981-05-08 1982-11-13 Yunitsuku:Kk Multiple hydraulic cylinder device
DE3615140A1 (en) * 1986-05-03 1987-11-05 Joh Tirre Ohg Maschf Pressure-medium-operated telescopic cylinder with at least two pistons guided one inside the other
DE8713223U1 (en) * 1987-10-01 1988-01-07 Dams, Joern, 4320 Hattingen, De

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7069728B2 (en) 2003-07-29 2006-07-04 Pratt & Whitney Canada Corp. Multi-position BOV actuator

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EP0350053A1 (en) 1990-01-10
DE58901623D1 (en) 1992-07-16
DE3823225A1 (en) 1990-01-11

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