EP0334924B1 - Lockable hydraulic cylinder - Google Patents

Lockable hydraulic cylinder Download PDF

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Publication number
EP0334924B1
EP0334924B1 EP88908198A EP88908198A EP0334924B1 EP 0334924 B1 EP0334924 B1 EP 0334924B1 EP 88908198 A EP88908198 A EP 88908198A EP 88908198 A EP88908198 A EP 88908198A EP 0334924 B1 EP0334924 B1 EP 0334924B1
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EP
European Patent Office
Prior art keywords
piston
locking
hydraulic cylinder
cylinder
locking parts
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP88908198A
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German (de)
French (fr)
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EP0334924A1 (en
Inventor
Gerhard Reuber
Reinhard Nowack
Jürgen LINKE
Rainer Jesse
Uwe Nerger
Eugen Fleisch
Peter Thiele
Gerhard NÜSSLE
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.)
Daimler Benz AG
Continental Teves AG and Co oHG
Original Assignee
Daimler Benz AG
Alfred Teves GmbH
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Publication of EP0334924A1 publication Critical patent/EP0334924A1/en
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Publication of EP0334924B1 publication Critical patent/EP0334924B1/en
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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
    • 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
    • F15B15/26—Locking mechanisms
    • F15B15/261—Locking mechanisms using positive interengagement, e.g. balls and grooves, for locking in the end positions

Definitions

  • the invention relates to a lockable hydraulic cylinder according to the preamble of claim 1.
  • Hydraulic cylinders of this type are used universally in technology and are distinguished, inter alia, by the fact that they can hold larger forces safely even in the locking position without pressure medium.
  • a piston-cylinder unit is known from DE-A-3 143 040, a locking piston movable perpendicular to the direction of movement of the working piston being provided which can be displaced into a recess in the piston rod.
  • This locking device requires a large amount of space and requires an additional pressure medium connection between the working piston and the locking piston.
  • a self-locking double-acting working cylinder in which a differential piston is axially displaceably mounted on the one hand on its outer diameter in the housing and on the other hand with its inner channel on a housing-fixed socket, with a locking piston which is on the one hand in the differential piston and on the other hand is mounted in the socket, the locking balls actuated.
  • this cylinder three components move relative to each other within the housing, which is a relatively complicated structure; on the other hand, a complex pressure medium connection within the differential piston is necessary.
  • the invention is therefore based on the object of creating a generic hydraulic cylinder in which the locking parts are held in a position-fixing engagement during the entire locking state. Furthermore, the hydraulic cylinder to be created should only have the smallest possible number of mutually movable parts with a simple structure, and the use of very small piston rods and piston diameters (6 to 16 mm) with very long strokes should be made possible.
  • the invention therefore consists in clamping the locking parts in the locked state by tapering surfaces of the locking piston. This also results in a whole series of advantages.
  • the clamping effect achieved results in a locking force.
  • the preload forces can thus be made smaller.
  • the valve opens very quickly when the ball is torn away.
  • the inventive measures also ensure that the balls are brought into the predetermined locking position, regardless of the position of the valve, so that the locking device can be operated both in a horizontal and in a vertical position with the same result.
  • the locking piston is provided in a blind bore in the cylinder base or in a component connected to it, it is advisable to improve the invention by using the features according to claim 3.
  • the locking parts can also be fixed in the unlocked state by using the features according to claim 4.
  • the position of the locking parts is in this state compared to the working piston and the locking piston precisely defined, which leads to a more precise triggering behavior in connection with the use of the features of claim 5.
  • these measures ensure that the locking parts moving with the working piston have no contact with the cylinder tube in the unlocked position. It is therefore made possible by these measures that the locking piston jams the locking parts in the unlocked position and the latter are only moved outward again when the locking position is reached by the deflection bushing.
  • the hydraulic cylinder shown in Fig. 1 consists of a cylinder tube 1, which is screwed to the cylinder bottom 2, and in which the working piston 3 is axially displaceable and is guided by the sealing rings 4 and 5 sealed.
  • the cylinder base 2 has a pressure connection 7 which can be connected to a pressure medium source and which is connected to the input space 8 also provided in the cylinder base 2.
  • a blind bore 13 is provided, in which a locking piston 6 is axially displaceable and acted upon by the spring 14 in the direction of the input space 8.
  • the spring 14 is supported on the one hand on the bottom of the blind bore 13 and on the other hand on a further blind bore 16 which is mounted in the locking piston 6.
  • the locking piston 6 is sealed by the sealing ring 17, which is located in an annular groove in the working piston 3 or locking piston 6.
  • the end section of the working piston 3 facing the input space 8 is provided on its jacket side with three radial through bores 15, in each of which a locking part 10 designed as a ball is guided in a radially movable manner.
  • the locking parts 10 are pressed radially outward into an annular groove-shaped radial recess 11 in the cylinder base 2 by the force of the spring 14 in conjunction with a first conical section 19 on the locking piston 6.
  • the sections of the locking parts 10 protruding from the working piston 3 in cooperation with the stop 12 prevent axial movement of the working piston 3.
  • the locking device described above is automatically unlocked. Due to the hydraulic pressure, the locking piston 6 is pushed into the blind bore 13 of the working piston 3 against the force of the spring 14. Characterized in that the sections of the locking piston 6 facing the input space 8 are each tapered in diameter, the locking parts 10 can move radially inward and thus release the locking in the piston head 2. During the movement of the working piston 3 in the cylinder tube 1, the locking parts 10 are pressed against the inner wall of the cylinder tube 1 by the remaining excess force of the spring 14 in connection with the second conical section 20 on the locking piston with a small radial force component.
  • the working piston 3 can be reset hydraulically, for example, via a working chamber opposite the input chamber 8 on the other side of the working piston, or mechanically via the piston rod 21 screwed into the working piston 3.
  • the locking piston 6 has a piston section 25, which is either very weakly conical, to which a cylindrical section 26 adjoins.
  • a piston section 25 which is either very weakly conical, to which a cylindrical section 26 adjoins.
  • a deflection bushing 29 is attached to the cylinder base 2 in the area of the input space 8. This has on its front side facing the working piston 3 an inclined chamfer 30 attached to the outer lateral surface.
  • the cylindrical section 26 of the locking piston 6 moves into the deflection bush 29, the locking parts 10 are moved radially outward by the action of the oblique chamfer 30.
  • radial passage channels 31 are provided distributed over the circumference of the deflection bushing 29.
  • the locking parts 10 do not cover an axial stroke path with the working piston 3.
  • the locking piston 6 is sealed by the seal 42 and axially displaceable in an insert cylinder 41 which is clamped to the cylinder base 2 by the screw 43.
  • a stepped, axial through bore is provided in the cylinder base 2; a sealing ring 44 is provided in an annular groove on the insert cylinder 41.
  • the insert cylinder 41 protrudes into an axial recess 45 which is provided in the working piston 3 on the end face facing the pressure connection 7.
  • This recess 45 is provided with a radial undercut into which the locking parts 10 can be moved to lock the working piston 3.
  • they are loaded radially outwards by the conical first step 46 on the locking piston 6 in cooperation with the compression spring 48 acting on the locking piston 6.
  • the working piston 3 is unlocked by introducing pressure into the pressure connection 7, which continues through the passage channels 49 in a radial expansion of the insert cylinder 41 into the working space 50 and from there through the radially extending channel 51 in the working piston 3.
  • the stepped piston 6 is moved into the insert cylinder 41 against the force of the compression spring 48. Due to the bevel 52 on the annular radially inward projection 53 on the working piston 3, the locking parts 10 are moved radially inward until they come to rest on the second step 47 of the locking piston 6.
  • the working piston 3 moves away from the pressure connection 7, while at the same time the return ring 54, which radially surrounds the insert cylinder 41 and is biased by the return spring 55, tracks the working piston 3 until the stop 56 of the return ring 54 on the step 57 of the insert cylinder 41 comes to rest.
  • the return spring 55 is supported on the one hand on the radial extension of the insert cylinder 41, to which the passage channel 49 is also attached, and on the other hand on an outer step of the return ring 54.
  • the path that the return ring 54 can travel conditionally through the return spring 55 is dimensioned such that the recesses 58, in which the locking parts 10 are guided, are passed axially. As a result, the locking parts 10 are secured against falling out of their recesses 58.

Abstract

A lockable hydraulic cylinder comprises a cylindrical tube (1) with at least one discharge connection (7), a working piston (3) sealed in the cylindrical tube (1) in which it slides, and a hydraulically operated closure element which engages with blocking elements (10). In order to achieve a compact locking unit which can also be incorporated in the cylinder and which has a small number of relatively moving parts of simple, compact design, the closure element is a differential piston (6) which travels in a sealed manner in a blind bore in the piston (3) and which is prestressed against the pressure in the direction of the locked position with an inlet space (8) adjoining the discharge connection (7). The diameter of the differential piston decreases near the inlet space (8) and the prestressed differential piston (6) exerts an outward radial force on the blocking elements (10). Radial recesses (11, 15) in which the blocking elements (10) engage are provided in the cylindrical tube (1) or in a component rigidly mounted on the latter, and in the piston (3).

Description

Die Erfindung betrifft einen verriegelbaren Hydraulikzylinder nach dem Oberbegriff des Anspruches 1.The invention relates to a lockable hydraulic cylinder according to the preamble of claim 1.

Derartige Hydraulikzylinder werden in der Technik universell angewandt und zeichnen sich unter anderem dadurch aus, daß sie in Verriegelungsstellung auch ohne Druckmedium größere Kräfte sicher halten können. Eine derartige Kolbenzylindereinheit ist aus der DE-A-3 143 040 bekannt, wobei ein senkrecht zur Bewegungsrichtung des Arbeitskolbens bewegbare Sperrkolben vorgesehen ist, welcher in eine Ausnehmung in der Kolbenstange verschiebbar ist. Diese Arretierungseinrichtung besitzt einen hohen Raumbedarf und erfordert eine zusätzliche Druckmittelverbindung zwischen dem Arbeitskolben und dem Arretierungskolben. Aus der DE-A-3 540 277 ist ein selbstsperrender doppelt wirkender Arbeitszylinder bekannt, bei dem ein Differentialkolben axial verschiebbar einerseits an seinem Außendurchmesser im Gehäuse und andererseits mit seinem Innenkanal an einer gehäusefesten Buchse gelagert ist, wobei ein Verschlußkolben, der einerseits im Differentialkolben und andererseits in der Buchse gelagert ist, die Verriegelungskugeln betätigt. Bei diesem Arbeitszylinder bewegen sich innerhalb des Gehäuses drei Bauteile relativ zueinander, wodurch sich ein relativ komplizierter Aufbau darstellt; zum anderen ist eine aufwendig zu fertigende Druckmittelverbindung innerhalb des Differentialkolbens nötig.Hydraulic cylinders of this type are used universally in technology and are distinguished, inter alia, by the fact that they can hold larger forces safely even in the locking position without pressure medium. Such a piston-cylinder unit is known from DE-A-3 143 040, a locking piston movable perpendicular to the direction of movement of the working piston being provided which can be displaced into a recess in the piston rod. This locking device requires a large amount of space and requires an additional pressure medium connection between the working piston and the locking piston. From DE-A-3 540 277 a self-locking double-acting working cylinder is known, in which a differential piston is axially displaceably mounted on the one hand on its outer diameter in the housing and on the other hand with its inner channel on a housing-fixed socket, with a locking piston which is on the one hand in the differential piston and on the other hand is mounted in the socket, the locking balls actuated. In this cylinder three components move relative to each other within the housing, which is a relatively complicated structure; on the other hand, a complex pressure medium connection within the differential piston is necessary.

Aus der US-A-2 887 991 ist ein gattungsgemäßer Hydraulikzylinder bekannt, der insofern nachteilig ist, daß die als Kugeln ausgestalteten Arretierungsteile im Verriegelungszustand in ihrer Lage nicht definiert sind. Diese Lage hängt vielmehr von der Druckdifferenz der auf den verriegelbaren Zylinder wirkenden Drücke ab. Ist diese Druckdifferenz hinreichend niederig, so bewegen sich die zur Arretierung dienenden Kugeln frei in einem dafür vorgesehenen Raum. Das kann zu unangenehmen Klappergeräuschen der Kugeln als auch zu Funktionsstörungen führen. Entsprechendes gilt für den aus der US-A-4 586 425 bekannten verriegelbaren Hydraulikzylinder, bei dem die Arretierungskugeln im Arretierungszustand ebenfalls nicht in radialer Richtung ständig belastet sind.From US-A-2 887 991 a generic hydraulic cylinder is known, which is disadvantageous in that the locking parts designed as balls are not defined in their position in the locked state. Rather, this position depends on the pressure difference between the pressures acting on the lockable cylinder. If this pressure difference is sufficiently low, the balls used for locking move freely in a space provided for this purpose. This can lead to unpleasant rattling noises from the balls as well as malfunctions. The same applies to the lockable hydraulic cylinder known from US-A-4 586 425, in which the locking balls are also not constantly loaded in the radial direction in the locked state.

Der Erfindung liegt daher die Aufgabe zugrunde, einen gattungsgemäßen Hydraulikzylinder zu schaffen, bei dem die Arretierungsteile während des gesamten Verriegelungszustandes in einem deren Lage fixierenden Eingriff gehalten werden. Weiterhin soll der zu schaffende Hydraulikzylinder nur eine möglichst geringe Anzahl zueinander beweglicher Teile mit einfachem Aufbau aufweisen, und es soll die Verwendung sehr kleiner Kolbenstangen und Kolbendurchmesser (6 bis 16 mm) bei sehr langen Hubwegen ermöglicht werden.The invention is therefore based on the object of creating a generic hydraulic cylinder in which the locking parts are held in a position-fixing engagement during the entire locking state. Furthermore, the hydraulic cylinder to be created should only have the smallest possible number of mutually movable parts with a simple structure, and the use of very small piston rods and piston diameters (6 to 16 mm) with very long strokes should be made possible.

Diese Aufgabe wird erfindungsgemäß durch die kennzeichnenden Merkmale des Anspruchs 1 gelöst. Die Erfindung besteht im Prinzip also darin, die Arretierungsteile im Arretierungszustand durch sich verjüngende Flächen des Verriegelungskolbens einzuklemmen. Hierdurch ergeben sich zusätzlich noch eine ganze Reihe von Vorteilen. Die erzielte Klemmwirkung hat eine die Verriegelung unterstützende Kraft zur Folge. Die Vorspannkräfte können somit kleiner gemacht werden. Weiterhin öffnet das Ventil bei Losreißen der Kugel sehr schnell. Durch die erfinderischen Maßnahmen ist es weiterhin sichergestellt, daß auch unabhänig von der Lage des Ventils die Kugeln in die vorbestimmte Verriegelungslage gebracht werden, so daß die Arretierungseinrichtung sowohl in waagerechter als auch in senkrechter Lage mit dem gleichen Ergebnis betrieben werden kann.This object is achieved by the characterizing features of claim 1. In principle, the invention therefore consists in clamping the locking parts in the locked state by tapering surfaces of the locking piston. This also results in a whole series of advantages. The clamping effect achieved results in a locking force. The preload forces can thus be made smaller. Furthermore, the valve opens very quickly when the ball is torn away. The inventive measures also ensure that the balls are brought into the predetermined locking position, regardless of the position of the valve, so that the locking device can be operated both in a horizontal and in a vertical position with the same result.

Einen besonders einfachen Aufbau des erfindungsgemäßen Hydraulikzylinders erhält man in Weiterbildung der Erfindung durch die Verwendung der Merkmale nach Anspruch 2.A particularly simple construction of the hydraulic cylinder according to the invention is obtained in a further development of the invention by using the features according to claim 2.

Ist der Verriegelungskolben in einer Sackbohrung des Zylinderbodens oder eines mit diesem verbundenen Bauteils vorgesehen, so empfiehlt sich in Verbesserung der Erfindung die Verwendung der Merkmale nach Anspruch 3.If the locking piston is provided in a blind bore in the cylinder base or in a component connected to it, it is advisable to improve the invention by using the features according to claim 3.

In Fortbildung der Erfindung läßt sich auch eine Fixierung der Arretierungsteile in entriegeltem Zustand durch Verwendung der Merkmale nach Anspruch 4 erreichen. Hierdurch ist die Lage der Arretierungsteile in diesem Zustand gegenüber dem Arbeitskolben und dem Verriegelungskolben genau definiert, was zu einer Präzisierung des Auslöseverhaltens in Verbindung mit der Verwendung der Merkmale nach Anspruch 5 führt. Weiterhin wird durch diese Maßnahmen erreicht, daß die sich mit dem Arbeitskolben bewegenden Arretierungsteile in entriegelter Stellung keinen Kontakt mit dem Zylinderrohr haben. Es wird daher durch diese Maßnahmen ermöglicht, daß der Verriegelungskolben die Arretierungsteile in entriegelter Stellung verklemmt und letztere erst wieder bei Erreichen der Verriegelungsstellung durch die Ablenkbuchse nach außen bewegt werden.In a further development of the invention, the locking parts can also be fixed in the unlocked state by using the features according to claim 4. As a result, the position of the locking parts is in this state compared to the working piston and the locking piston precisely defined, which leads to a more precise triggering behavior in connection with the use of the features of claim 5. Furthermore, these measures ensure that the locking parts moving with the working piston have no contact with the cylinder tube in the unlocked position. It is therefore made possible by these measures that the locking piston jams the locking parts in the unlocked position and the latter are only moved outward again when the locking position is reached by the deflection bushing.

Eine besonders einfache Ausgestaltung für die Arretierungsteile ergibt sich durch die Verwendung der Merkmale nach Anspruch 6.A particularly simple configuration for the locking parts results from the use of the features according to claim 6.

Die Funktion und andere erfindungswesentlichen Merkmale ergeben sich aus der nachfolgenden Beschreibung von drei bevorzugten Ausführungsformen der Erfindung.The function and other features essential to the invention result from the following description of three preferred embodiments of the invention.

Hierzu zeigt:

  • Fig. 1 ein erstes Ausführungsbeispiel
  • Fig. 2 eine zweites Ausführungsbeispiel der Erfindung im verriegelten Zustand
  • Fig. 3 ein Ausführungsbeispiel nach Fig. 2 in entriegeltem Zustand,
  • Fig. 4 ein drittes Ausführungsbeispiel der Erfindung.
This shows:
  • Fig. 1 shows a first embodiment
  • Fig. 2 shows a second embodiment of the invention in the locked state
  • 3 shows an embodiment according to FIG. 2 in the unlocked state,
  • Fig. 4 shows a third embodiment of the invention.

Bei allen Figuren werden für einander entsprechende Teile die gleichen Bezugszeichen gewählt.In all figures, the same reference numerals are chosen for corresponding parts.

Der in Fig. 1 dargestellte Hydraulikzylinder besteht aus einem Zylinderrohr 1, das mit dem Zylinderboden 2 verschraubt ist, und in welchem der Arbeitskolben 3 axial verschiebbar und durch die Dichtringe 4 und 5 abgedichtet geführt ist. Der Zylinderboden 2 besitzt einen an eine Druckmittelquelle anschließbaren Druckanschluß 7, welcher mit dem ebenfalls im Zylinderboden 2 vorgesehenen Eingangsraum 8 verbunden ist. In der dem Eingangsraum 8 zugewandten Stirnseite des Arbeitskolbens 3 ist eine Sackbohrung 13 angebracht, in welcher ein Verriegelungskolben 6 axial verschieblich und durch die Feder 14 in Richtung auf den Eingangsraum 8 beaufschlagt angeordnet ist. Hierzu stützt sich die Feder 14 zum einen am Boden der Sackbohrung 13 und zum anderen an einer weiteren Sackbohrung 16 ab, welche im Verriegelungskolben 6 angebracht ist. Der Verriegelungskolben 6 ist durch den Dichtring 17 abgedichtet, welcher sich in einer Ringnut im Arbeitskolben 3 oder Verriegelungskolben 6 befindet.The hydraulic cylinder shown in Fig. 1 consists of a cylinder tube 1, which is screwed to the cylinder bottom 2, and in which the working piston 3 is axially displaceable and is guided by the sealing rings 4 and 5 sealed. The cylinder base 2 has a pressure connection 7 which can be connected to a pressure medium source and which is connected to the input space 8 also provided in the cylinder base 2. In the end face of the working piston 3 facing the input space 8, a blind bore 13 is provided, in which a locking piston 6 is axially displaceable and acted upon by the spring 14 in the direction of the input space 8. For this purpose, the spring 14 is supported on the one hand on the bottom of the blind bore 13 and on the other hand on a further blind bore 16 which is mounted in the locking piston 6. The locking piston 6 is sealed by the sealing ring 17, which is located in an annular groove in the working piston 3 or locking piston 6.

Der dem Eingangsraum 8 zugewandte Endabschnitt des Arbeitskolbens 3 ist an seiner Mantelseite mit drei radialen Durchgangsbohrungen 15 versehen, in welchen jeweils ein als Kugel ausgebildetes Arretierungsteil 10 radial beweglich geführt ist. Die Arretierungsteile 10 werden in der dargestellten, verriegelten Lage durch die Kraft der Feder 14 in Verbindung mit einem ersten konischen Abschnitt 19 am Verriegelungskolben 6 radial nach außen in eine ringnutförmige radiale Ausnehmung 11 im Zylinderboden 2 gedrückt. Die jeweils aus dem Arbeitskolben 3 herausragenden Abschnitte der Verriegelungsteile 10 verhindern in Zusammenwirkung mit dem Anschlag 12 eine axiale Bewegung des Arbeitskolbens 3.The end section of the working piston 3 facing the input space 8 is provided on its jacket side with three radial through bores 15, in each of which a locking part 10 designed as a ball is guided in a radially movable manner. In the illustrated, locked position, the locking parts 10 are pressed radially outward into an annular groove-shaped radial recess 11 in the cylinder base 2 by the force of the spring 14 in conjunction with a first conical section 19 on the locking piston 6. The sections of the locking parts 10 protruding from the working piston 3 in cooperation with the stop 12 prevent axial movement of the working piston 3.

Soll dagegen der Arbeitskolben 3 durch Druckmittelbeaufschlagung über den Druckanschluß 7 und den Eingangsraum 8 hydraulisch bewegt werden, so entriegelt sich die oben beschriebene Sperreinrichtung selbsttätig. Durch den hydraulischen Druck wird der Verriegelungskolben 6 gegen die Kraft der Feder 14 in die Sackbohrung 13 des Arbeitskolben 3 hineingeschoben. Dadurch, daß die dem Eingangsraum 8 zugewandten Abschnitte des Verriegelungskolben 6 jeweils im Durchmesser verjüngt sind, können sich die Arretierungsteile 10 radial nach innen bewegen und somit die Verriegelung im Kolbenboden 2 aufheben. Während der Bewegung des Arbeitskolbens 3 im Zylinderrohr 1 werden die Arretierungsteile 10 durch die verbleibende Überschußkraft der Feder 14 in Verbindung mit dem zweiten konischen Abschnitt 20 am Verriegelungskolben mit einer geringen Radialkraftkomponente an die Innenwand des Zylinderohres 1 gedrückt.If, on the other hand, the working piston 3 is to be moved hydraulically by the application of pressure medium via the pressure connection 7 and the input space 8, the locking device described above is automatically unlocked. Due to the hydraulic pressure, the locking piston 6 is pushed into the blind bore 13 of the working piston 3 against the force of the spring 14. Characterized in that the sections of the locking piston 6 facing the input space 8 are each tapered in diameter, the locking parts 10 can move radially inward and thus release the locking in the piston head 2. During the movement of the working piston 3 in the cylinder tube 1, the locking parts 10 are pressed against the inner wall of the cylinder tube 1 by the remaining excess force of the spring 14 in connection with the second conical section 20 on the locking piston with a small radial force component.

Die Rückstellung des Arbeitskolbens 3 kann beispielsweise über eine dem Eingangsraum 8 gegenüberliegende Arbeitskammer auf der anderen Seite des Arbeitskolbens hydraulisch erfolgen, oder aber auch mechanisch über die im Arbeitskolben 3 verschraubte Kolbenstange 21.The working piston 3 can be reset hydraulically, for example, via a working chamber opposite the input chamber 8 on the other side of the working piston, or mechanically via the piston rod 21 screwed into the working piston 3.

Für die in Fig. 2 und Fig. 3 dargestellte Ausführungsform trifft im wesentlichen das zu, was bereits im Zusammenhang mit Fig. 1 erläutert wurde. Im folgenden werden lediglich die Unterschiede gegenüber der Ausführungsformen nach Fig. 1 beschrieben.For the embodiment shown in FIGS. 2 and 3, essentially that which has already been explained in connection with FIG. 1 applies. Only the differences compared to the embodiments according to FIG. 1 are described below.

Zur Beaufschlagung der Arretierungsteile weist der Verriegelungskolben 6 einen Kolbenabschnitt 25 auf, der entweder sehr schwach konisch ausgeführt ist, an den sich ein zylindrischer Abschnitt 26 anschließt. Dadurch wird in entriegeltem Zustand, wie er in Fig. 3 dargestellt ist, keine Radialkraftkomponente nach außen auf die Arretierungsteile 10 wirksam. Dies hat zur Folge, daß die Arretierungsteile 10 in entriegeltem Zustand zwischen den Kanten 27,28 am Arbeitskolben 3 bzw. am Verriegelungskolben 6 durch die Kraft der Feder 14 eingeklemmt werden und sich in eingerückter Lage halten.To act on the locking parts, the locking piston 6 has a piston section 25, which is either very weakly conical, to which a cylindrical section 26 adjoins. As a result, in the unlocked state, as shown in FIG. 3, no radial force component acts on the locking parts 10 to the outside. The result of this is that the locking parts 10 are clamped in the unlocked state between the edges 27, 28 on the working piston 3 or on the locking piston 6 by the force of the spring 14 and hold in the engaged position.

Es besteht also während der Bewegung des Arbeitskolbens 3 im Zylinderrohr 1 kein Kontakt zwischen der Zylinderrohrinnenwand und den Arretierungsteilen 10, wodurch keine besonderen Maßnahmen wie beispielsweise Härten, Nitrieren oder Galvanisieren an der Innenfläche des Zylinderrohres 1 notwendig sind.There is therefore no contact between the inner wall of the cylinder tube and the locking parts 10 during the movement of the working piston 3 in the cylinder tube 1, as a result of which no special measures such as hardening, nitriding or galvanizing are necessary on the inner surface of the cylinder tube 1.

Um beim Erreichen der Verriegelungslage die Arretierungsteile 10 aus dieser eingerückten Lage wieder zu lösen ist am Zylinderboden 2 im Bereich des Eingangsraums 8 eine Ablenkbuchse 29 angebracht. Diese weist an ihrer dem Arbeitskolben 3 zugewandten Stirnseite eine an der äußeren Mantelfläche angebrachte schräge Anfasung 30 auf. Beim Erreichen der Verriegelungslage bewegt sich der zylindrische Abschnitt 26 des Verriegelungskolben 6 in die Ablenkbuchse 29 hinein, die Arretierungsteile 10 werden durch die Beaufschlagung mit der schrägen Anfasung 30 radial nach außen bewegt. Um eine optimale Druckbeaufschlagung des Arbeitskolbens 3 aus der verriegelten Lage heraus zu erreichen, sind radiale Durchlaßkanäle 31 am Umfang der Ablenkbuchse 29 verteilt vorgesehen.In order to release the locking parts 10 from this engaged position when the locking position is reached, a deflection bushing 29 is attached to the cylinder base 2 in the area of the input space 8. This has on its front side facing the working piston 3 an inclined chamfer 30 attached to the outer lateral surface. When the locking position is reached, the cylindrical section 26 of the locking piston 6 moves into the deflection bush 29, the locking parts 10 are moved radially outward by the action of the oblique chamfer 30. In order to achieve an optimal pressurization of the working piston 3 from the locked position, radial passage channels 31 are provided distributed over the circumference of the deflection bushing 29.

Bei der Ausführungsform nach Fig. 4 ist vorgesehen, daß die Arretierungsteile 10 keinen axialen Hubweg mit dem Arbeitskolben 3 zurücklegen. Der Verriegelungskolben 6 befindet sich durch die Dichtung 42 abgedichtet axial verschiebbar in einem Einsatzzylinder 41, welcher mit dem Zylinderboden 2 durch die Schraube 43 verspannt ist. Hierzu ist im Zylinderboden 2 eine gestufte, axiale Durchgangsbohrung vorgesehen; ein Dichtring 44 ist in einer Ringnut am Einsatzzylinder 41 vorgesehen. In verriegeltem Zustand, wie er in Fig. 4 dargestellt ist, ragt der Einsatzzylinder 41 in eine axiale Ausnehmung 45, welche im Arbeitskolben 3 an der dem Druckanschluß 7 zugewandten Stirnseite angebracht ist. Diese Ausnehmung 45 ist mit einer radialen Hinterschneidung versehen, in welche die Arretierungsteile 10 zur Verriegelung des Arbeitskolbens 3 bewegt werden können. Hierzu werden sie durch die konische erste Stufe 46 am Verriegelungskolben 6 in Zusammenwirkung mit der den Verriegelungskolben 6 beaufschlagenden Druckfeder 48 radial nach außen belastet.In the embodiment according to FIG. 4 it is provided that the locking parts 10 do not cover an axial stroke path with the working piston 3. The locking piston 6 is sealed by the seal 42 and axially displaceable in an insert cylinder 41 which is clamped to the cylinder base 2 by the screw 43. For this purpose, a stepped, axial through bore is provided in the cylinder base 2; a sealing ring 44 is provided in an annular groove on the insert cylinder 41. In the locked state, as shown in FIG. 4, the insert cylinder 41 protrudes into an axial recess 45 which is provided in the working piston 3 on the end face facing the pressure connection 7. This recess 45 is provided with a radial undercut into which the locking parts 10 can be moved to lock the working piston 3. For this purpose, they are loaded radially outwards by the conical first step 46 on the locking piston 6 in cooperation with the compression spring 48 acting on the locking piston 6.

Die Entriegelung des Arbeitskolbens 3 geschieht durch Druckeinleitung in den Druckanschluß 7, die sich über die Durchlaßkanäle 49 in einer radialen Erweiterung des Einsatzzylinders 41 in den Arbeitsraum 50 und von dort aus durch den radial verlaufenden Kanal 51 im Arbeitskolben 3 fortsetzt. Über diesen Weg wird bei Druckeinleitung der Stufenkolben 6 gegen die Kraft der Druckfeder 48 in den Einsatzzylinder 41 hinein bewegt. Durch die Schräge 52 am ringförmigen radial nach innen weisenden Vorsprung 53 am Arbeitskolben 3 werden die Arretierungsteile 10 radial nach innen bewegt, bis sie an der zweiten Stufe 47 des Verriegelungskolbens 6 zur Anlage kommen. Durch die Druckbeaufschlagung verschiebt sich der Arbeitskolben 3 vom Druckanschluß 7 weg, während gleichzeitig der Rückstellring 54, der den Einsatzzylinder 41 radial umgibt und durch die Rückstellfeder 55 vorgespannt ist, dem Arbeitskolben 3 nachgeführt wird, bis der Anschlag 56 des Rückstellringes 54 an der Stufe 57 des Einsatzzylinders 41 zum Anliegen kommt. Die Rückstellfeder 55 stützt sich zum einen an der radialen Erweiterung des Einsatzzylinders 41, an dem auch der Durchlaßkanal 49 angebracht ist, und zu anderen an einer Außenstufe des Rückstellringes 54 ab. Der Weg den der Rückstellring 54 durch die Rückstellfeder 55 bedingt zurücklegen kann, ist dabei so bemessen, daß die Ausnehmungen 58, in denen die Arretierteile 10 geführt sind, axial überfahren werden. Hierdurch sind die Arretierteile 10 gegen ein Herausfallen aus ihren Ausnehmungen 58 gesichert.The working piston 3 is unlocked by introducing pressure into the pressure connection 7, which continues through the passage channels 49 in a radial expansion of the insert cylinder 41 into the working space 50 and from there through the radially extending channel 51 in the working piston 3. When the pressure is introduced, the stepped piston 6 is moved into the insert cylinder 41 against the force of the compression spring 48. Due to the bevel 52 on the annular radially inward projection 53 on the working piston 3, the locking parts 10 are moved radially inward until they come to rest on the second step 47 of the locking piston 6. Due to the pressurization, the working piston 3 moves away from the pressure connection 7, while at the same time the return ring 54, which radially surrounds the insert cylinder 41 and is biased by the return spring 55, tracks the working piston 3 until the stop 56 of the return ring 54 on the step 57 of the insert cylinder 41 comes to rest. The return spring 55 is supported on the one hand on the radial extension of the insert cylinder 41, to which the passage channel 49 is also attached, and on the other hand on an outer step of the return ring 54. The path that the return ring 54 can travel conditionally through the return spring 55 is dimensioned such that the recesses 58, in which the locking parts 10 are guided, are passed axially. As a result, the locking parts 10 are secured against falling out of their recesses 58.

Beim Zurückfahren des Arbeitskolbens 3 in Richtung Verriegelungsstellung wird der Rückstellring 54 durch die Stirnseite des Arbeitskolbens 3 gegen die Kraft der Rückstellfeder 55 verschoben. Hat der Vorsprung 53 die Ausnehmung 58 im Einsatzzylinder 41 überfahren, so werden die Arretierungsteile 10 durch den vorgespannten Verriegelungskolben 6, der sich in Richtung auf den Arbeitszylinder 3 bewegt, radial nach außen beaufschlagt. Der Arbeitskolben 3 ist somit wieder verriegelt.When the working piston 3 moves back in the direction of the locking position, the return ring 54 is displaced by the end face of the working piston 3 against the force of the return spring 55. If the projection 53 has passed over the recess 58 in the insert cylinder 41, the locking parts 10 are acted upon radially outwards by the prestressed locking piston 6, which moves in the direction of the working cylinder 3. The working piston 3 is thus locked again.

Claims (7)

1. A lockable hydraulic cylinder with a cylinder tube (1), with at least one pressure port (7), a displaceable working piston (3) sealedly arranged in the cylinder tube (1), with a hydraulically actuatable locking piston (6) serving to move locking parts (10) into engagement with recesses (11, 15, 45, 58), the said locking piston (6) being sealedly guided in relation to the pressure at the pressure port and being preloaded in the direction of the locked position in opposition to the pressure in an inlet chamber (8, 45) communicating with the pressure port (7), the said locking piston (6) comprising a tapering portion (19, 20, 25, 46), the said radial recesses (11, 15, 45, 58) into which the locking parts (10) are engageable being provided in the cylinder tube (1) or in a component part (41) rigidly coupled to the latter as well as in the working piston (3), characterized in that the locking piston (6) guided in a blind-end bore (13), subjected to preload, applies a radially outwardly directed force on the locking parts (10) in the locked condition, and in that the outwardly directed force is exerted by a conical surface (19, 51) of the tapering portion (19, 20, 25, 46).
2. A hydraulic cylinder as claimed in claim 1, characterized in that the tapering portion (19, 25) is arranged at the inlet-side end of the locking piston (6) and tapers towards the inlet chamber (8).
3. A hydraulic cylinder as claimed in claim 1, characterized in that a portion (41) on the bottom (2) of the cylinder tube (1), in which the locking piston (6) is guided, is radially encompassed by a resetting ring (54) which latter, while displaceable within limits, is biassed by a resetting spring (55).
4. A hydraulic cylinder as claimed in any one of the claims 1 to 3, characterized in that in the unlocked position the locking parts (10) by preload are acted upon by a radially inwardly directed force, the said inwardly directed force being given by a tilting torque which is exerted on the locking parts (10) by way of an edge in the recess (15) in the working piston and by way of a surface (28) which extends substantially transversely to the direction of motion of the locking piston (6) and is arranged thereon.
5. A hydraulic cylinder as claimed in claim 4, characterized in that in the locked position the end of the locking piston (6) projecting into the inlet chamber (8) extends into a deflection bushing (29) which is provided with an inclined chamfer (30) that acts outwardly upon the locking parts (10).
6. A hydraulic cylinder as claimed in any one of the claims 1 to 5, characterized in that the locking parts (10) are designed as balls.
7. A hydraulic cylinder as claimed in any one of the claims 1 to 6, characterized in that a locking unit is provided on both end surfaces of the working piston (3) and the cylinder tube (1), more particularly symmetrically to the radial plane.
EP88908198A 1987-09-26 1988-09-13 Lockable hydraulic cylinder Expired - Lifetime EP0334924B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19873732561 DE3732561A1 (en) 1987-09-26 1987-09-26 LOCKABLE HYDRAULIC CYLINDER
DE3732561 1987-09-26

Publications (2)

Publication Number Publication Date
EP0334924A1 EP0334924A1 (en) 1989-10-04
EP0334924B1 true EP0334924B1 (en) 1992-06-17

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ID=6337005

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88908198A Expired - Lifetime EP0334924B1 (en) 1987-09-26 1988-09-13 Lockable hydraulic cylinder

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EP (1) EP0334924B1 (en)
JP (1) JP2701906B2 (en)
DE (2) DE3732561A1 (en)
WO (1) WO1989002987A1 (en)

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Also Published As

Publication number Publication date
WO1989002987A1 (en) 1989-04-06
JPH02501403A (en) 1990-05-17
EP0334924A1 (en) 1989-10-04
DE3732561C2 (en) 1992-10-08
DE3732561A1 (en) 1989-04-13
DE3872222D1 (en) 1992-07-23
JP2701906B2 (en) 1998-01-21

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