EP2503162A1 - Fluid-actuated rotary drive - Google Patents

Abstract

The fluid operated rotary drive device (1) comprises a housing (2) and an output unit (38), which is rotatably mounted corresponding to the housing and is rotatable by carrying out a rotary output movement between two rotation end positions. A locking unit is supported corresponding to the housing in axial direction of a main axis (3) and is switchable from a release position for axial releasing process of a stop unit (58a,58b) into a locking position in locking engagement with the stop unit for blocking the stop position independent from forces causing the movement of the assigned stop unit.

Description

• ein Gehäuse,
• eine bezüglich des Gehäuses drehbar gelagerte und unter Ausführung einer rotativen Abtriebsbewegung zwischen zwei Dreh-Endpositionen verdrehbare Abtriebseinheit,
• mindestens eine in einem Antriebsraum des Gehäuses angeordnete und durch gesteuerte Fluidbeaufschlagung zu einer in Achsrichtung einer Hauptachse des Gehäuses orientierten linearen Antriebsbewegung zwischen zwei Hubendlagen antreibbare Antriebseinheit, die zur Erzeugung der rotativen Abtriebsbewegung über Getriebemittel mit der Abtriebseinheit bewegungsgekoppelt ist,
• und eine Positionsvorgabeeinrichtung, die mindestens eine im Verfahrweg mindestens einer Antriebseinheit angeordnete Anschlageinheit aufweist, die in Achsrichtung der Hauptachse relativ zum Gehäuse bewegbar ist und die zur Vorgabe mindestens einer zwischen den beiden Dreh-Endpositionen liegenden Dreh-Zwischenposition der Abtriebseinheit in einer das Erreichen einer Hubendlage der zugeordneten Antriebseinheit verhindernden Anschlagposition relativ zu dem Gehäuse lösbar blockierbar ist.

The invention relates to a fluid-operated rotary drive device, comprising:

• a housing,
• a rotatably mounted relative to the housing and rotatable under execution of a rotary output movement between two rotary end positions output unit,
• at least one drive unit, which is arranged in a drive space of the housing and can be driven by controlled fluid admission to a linear drive movement oriented between two stroke end positions in the axial direction of the housing, is motion-coupled to the output unit for generating the rotary output motion via transmission means;
• and a position setting device, which has at least one arranged in the travel of at least one drive unit stop unit which is movable relative to the housing in the axial direction of the main axis and to specify at least one lying between the two rotational end positions rotational intermediate position of the output unit in a reaching a Hubendlage the associated drive unit preventing stop position relative to the housing is detachably lockable.

One from the DE 19803819 B4 known rotary drive device of this type has a multi-part housing, on which an output unit is rotatably mounted, on which a component to be moved in rotation can be fixed. The output unit is in drive connection via transmission means with two drive units mounted linearly displaceably in the interior of the housing, which can be driven by applying fluid to a reciprocating linear drive movement in order to produce an oscillatory output rotary movement of the output unit. The two drive units can be moved between two Hubendlagen in which the output unit occupies one of two possible rotational end positions. In order to be able to position the output unit even in a rotational intermediate position lying between the two rotary end positions, the rotary drive device is additionally equipped with a positioning device which has two stop parts combined into an only uniformly movable stop unit, each in extension of one of the two drive units are arranged. In order to spend the drive unit in a rotational intermediate position, the stop unit is moved in the fluidically unencumbered state of the drive units by means of fluid force in the direction of the drive units, so that selbige mechanically driven and are moved so far, is applied to each stop part of the two stop units. The output unit is fixed as long in its intermediate rotational position, as the stop unit is under fluid loading.

A disadvantage of the known rotary drive device is that an active use of the stop unit is required is to shift the drive units in a desired rotational intermediate position predetermining intermediate stroke position. The position setting device is used to specify the rotational intermediate position as a thrust drive device for actuating the drive units, which requires a complex and especially bulky design. This drives up the manufacturing costs.

From the EP 1 703 144 B1 a fluid-actuated linear drive is known, which has an axially immovable by means of a locking device blockable output unit.

The invention has for its object to provide a rotary drive device that allows for cost-effective production of a precise specification of at least one rotational intermediate position of the output unit.

To achieve this object, it is provided that the position setting device includes a locking device which has at least one relative to the housing in the axial direction of the main axis supported and transversely to this main axis controlled relative to both the housing and the stop unit movable locking member, to block the stop position at least one stop unit is movable in a releasable mechanical locking engagement with the stop unit to be blocked, wherein the at least one drive unit by their Fluidbeaufschlagung relative to the previously locked in a stop position stop unit from a Hubendlage defined by the locked stop unit and the rotary intermediate position predetermining stroke Intermediate position is movable.

In this way, the output unit can be rotated without the action of the position setting device and solely by controlled fluid loading of the at least one drive unit from a rotary end position to the desired rotational intermediate position. The position presetting device is used only for presetting or for defining the rotational intermediate position by stopping the at least one drive unit when the same has reached its intermediate stroke position corresponding to the rotational intermediate position during its drive movement. Thus, since the torque required to rotate the output unit into the rotational intermediate position is applied by the same components as the torque required for rotation between two rotational end positions, namely by the at least one controllable fluid actuated drive unit, the position presetting device can be made smaller in size , resulting in moderate manufacturing costs. Favorable in this regard also has the effect that the drive unit in the rotational intermediate position predetermining stop position is locked mechanically fixed to the housing, so that an exact position specification is guaranteed and the output unit is independent of any pressure fluctuations backlash in its intermediate rotational position can be fixed. A further advantage of the rotary drive device is that the locking engagement can be canceled when the output unit is in a rotational intermediate position, so that the output unit can be selectively rotated into each of its two rotary end positions starting from the rotary intermediate position. The rotary drive device is characterized very variable use.

Advantageous developments of the invention will become apparent from the dependent claims.

The transmission means used to implement the linear movement of the at least one drive unit in the rotary movement of the output unit expediently comprise a driven sprocket arranged on the output unit and furthermore a rack-like drive toothing meshing with the driven sprocket on each drive unit.

Particularly advantageous is a structure in which the rotary drive device has two juxtaposed and in opposite directions linearly driven drive units, both of which are motion-coupled to the output unit via the gear means. The two drive units are expediently provided on the mutually facing longitudinal sides, each with a rack-like drive toothing, wherein the output unit is immersed with a driven sprocket between the two drive units and at the same time is engaged with both drive teeth. By the two drive units can be actuated by fluid force, thus a particularly high torque can be transmitted to the output unit. At the same time a symmetrical force is introduced into the output unit, which favors their life. However, it would be quite possible to equip the rotary drive device with only a single drive unit.

Conveniently, the position setting device is equipped with two each one of the drive units functionally associated stop units, which are movable independently relative to the housing of the rotary drive device and by the locking device in each case in at least one stop position fixed to the housing releasably mechanically are lockable. The independent design of the two drive units makes it possible to specify at least two different rotational intermediate positions of the output unit. The two stop units are not coupled to each other motion and can therefore be moved without mutual interference in its stop position.

The locking device may have a single locking member which can be used to lock both stop units, in particular such that it releases the respective other stop unit upon locking of each one stop unit. However, the position presetting device can be operated more universally and flexibly if the locking device has two independently operable locking members, so that each stop unit is assigned its own locking element individually and thus the two stop units can also be locked and unlocked independently of each other. The positioning operations can be carried out in this way very time-saving.

An expedient construction of the rotary drive device provides that each stop unit is arranged in coaxial extension of the drive unit cooperating with it. Above all, such an embodiment also favors a modular design of the rotary drive device, since in this case the advantageous possibility exists of realizing the position presetting device as part of an independent position presetting module which can be attached to a drive module comprising the at least one drive unit and the output unit.

Each stop unit expediently has a counter-locking member provided for cooperation with the locking member, which is displaceable relative to the housing in the axial direction of the main axis. As a result of this displaceability, it can optionally be positioned in a stop position for locking with the locking element or in at least one axial position deviating therefrom. The counter-locking member also assumes the function of carrying a stop surface, which is expediently facing the case to case in a stroke intermediate position to stop drive unit and which can cooperate with locked in the stop position counter-locking member with this drive unit so selbige is stopped in the desired intermediate stroke position. Depending on the configuration, the stop surface can cooperate directly or indirectly with the associated drive unit. In other words, when the stroke intermediate position is reached, the drive unit can either run directly onto the stop surface or it is supported on an intermediate member, which in turn is supported on the stop surface. As a possible intermediate member of this kind comes in particular a movable shock absorber member of a fluidic shock absorber in question, with which the stop unit can be equipped.

It is advantageous if the counter-locking member carries a fluidic shock absorber, which has a projecting in the travel of the associated drive unit movable shock absorber member and which ensures that the drive unit is gently braked when reaching its intermediate stroke position.

A particularly compact arrangement can be realized if the counter-locking member has an axially open cavity in the direction of the drive unit to be stopped occasionally in a stroke intermediate position, in which a for setting the intermediate stroke position directly or indirectly with the above mentioned abutment surface cooperating plunger plunger, which is coupled for movement with the drive unit. In particular, the stop ram is an integral part of the drive unit, so that it synchronously participates in its lifting movement in both directions. Conveniently, the stopper plunger is screwed into a drive body of the drive unit. The stop ram has expediently a smaller diameter than said drive body and protrudes in particular coaxial arrangement of this drive body away.

Preferably, the stop ram always protrudes into the cavity of the counter-locking member regardless of the relative position occupied between the associated drive unit and the stop unit cooperating therewith. It is advantageous if the stop ram is guided linearly displaceable by the counter-locking member.

For the counter-locking member is recommended a sleeve-shaped design with a continuous cavity in the axial direction. The stop plunger dips here from a front side into the counter-locking member. At the opposite rear end portion, in particular in an axially adjustable manner, a fluidic shock absorber can be fixed, which cooperates with the stop ram inside the cavity. The stop plunger expediently has on its front side a counter-abutment surface which cooperates with the fluidic shock absorber.

If a drive unit is moved from an intermediate hub position after unlocking the locking device previously in the previously inaccessible Hubendlage, it pushes the associated stop unit expediently in front of him. For this purpose, the Stop unit expediently received axially displaceable in a positioning of the housing, which is separated from the associated drive unit receiving drive space expediently fluid-tight. When the drive unit is subsequently moved again in the direction of its other stroke end position, the stop unit can follow the drive unit by means of its associated drive means in order to reach the stop position again in order to be able to be locked there. The drive means are in particular designed so that the stop unit is adjustable by fluid force and / or electrically and in any case without movement coupling with the associated drive unit in the stop position. However, it is also a pertinent embodiment of the drive means possible that the stop unit of the retracting drive unit is a piece far, taken to reach the stop position. Such drive means may be embodied for example in the form of a detachable latching connection device.

The controlled actuation of the at least one locking member of the locking device is expediently carried out by means of fluid force. Each locking member may be biased by spring means in the direction of a locking position, from which it can be switched by applying a fluidic pressure force in case of need in a release position for unlocking the associated stop unit. The effect of the spring force and the fluid force can also be reversed. It is also possible to provide an electrical actuation of the at least one locking member. In order to be able to easily carry out furnishing work, it is also expedient if, for actuation of the at least one locking member, a manual override device is present, with which it is purely manual and without assistance of foreign energy switching the locking member can be made.

Figur 1

eine bevorzugte Ausführungsform der erfindungsgemäßen Drehantriebsvorrichtung in einer perspektivischen Außenansicht,

Figur 2

einen Querschnitt durch die Drehantriebsvorrichtung gemäß Schnittlinie II-II aus Figuren 1 und 3,

Figur 3

einen Längsschnitt durch die Drehantriebsvorrichtung gemäß Schnittlinie III-III aus Figuren 1 und 2, wobei der Betriebszustand bei Einnahme einer ersten Dreh-Endposition der Abtriebseinheit gezeigt ist,

Figur 4

die Drehantriebsvorrichtung in einer der Figur 3 entsprechenden Längsschnittdarstellung, wobei ein Betriebszustand bei Einnahme einer ersten Dreh-Zwischenposition der Abtriebseinheit gezeigt ist,

Figur 5

in einer den Figuren 3 und 4 entsprechenden Darstellungsweise einen Betriebszustand bei Einnahme einer zweiten Dreh-Endposition durch die Abtriebseinheit,

Figur 6

einen Querschnitt durch die Drehantriebsvorrichtung im Bereich der Verriegelungseinrichtung und gemäß Schnittlinie VI-VI aus Figur 3,

Figur 7

den in Figur 3 strichpunktiert umrahmten Ausschnitt VII der Drehantriebsvorrichtung im Bereich der Verriegelungseinrichtung und in einem vergrößerten Maßstab, und

Fig. 8-11

verschiedene Betriebszustände der Drehantriebsvorrichtung, in denen die Abtriebseinheit unterschiedliche Drehpositionen einnimmt, wobei die Figur 8 eine erste Dreh-Endposition, die Figur 9 eine erste Dreh-Zwischenposition, die Figur 10 eine zweite Dreh-Endposition und die Figur 11 eine zweite Dreh-Zwischenposition illustriert.

The invention will be explained in more detail with reference to the accompanying drawings. In this show:

FIG. 1

a preferred embodiment of the rotary drive device according to the invention in a perspective exterior view,

FIG. 2

a cross section through the rotary drive device according to section line II-II FIGS. 1 and 3 .

FIG. 3

a longitudinal section through the rotary drive device according to section line III-III Figures 1 and 2 wherein the operating state is shown assuming a first rotational end position of the output unit,

FIG. 4

the rotary drive device in one of FIG. 3 corresponding longitudinal sectional view, wherein an operating state when assuming a first rotational intermediate position of the output unit is shown,

FIG. 5

in a the Figures 3 and 4 corresponding representation of an operating state when taking a second rotational end position by the output unit,

FIG. 6

a cross section through the rotary drive device in the region of the locking device and according to section line VI-VI FIG. 3 .

FIG. 7

the in FIG. 3 dash-dotted framed section VII of the rotary drive device in the region of the locking device and on an enlarged scale, and

Fig. 8-11

various operating states of the rotary drive device, in which the output unit occupies different rotational positions, wherein the FIG. 8 a first rotational end position, the FIG. 9 a first rotational intermediate position, the FIG. 10 a second rotary end position and the FIG. 11 illustrates a second intermediate rotary position.

The rotary drive device designated in its entirety by reference numeral 1 is designed for actuation by means of fluid force and can be driven by means of a fluidic and preferably gaseous pressure medium. Preferably, compressed air is provided as drive medium.

The rotary drive device 1 has a preferably elongate and in particular multi-part housing 2 formed. The housing 2 has an imaginary, indicated in phantom in the drawing main axis 3, which is suitably formed by the longitudinal axis of the housing 2.

The housing 2 has a transverse axis 4 which is perpendicular to the main axis 3 and a vertical axis 5 which is perpendicular to both the main axis 3 and the transverse axis 4. The main axis 3 and the transverse axis 4 jointly span a plane designated as the main plane 6 FIGS. 3 to 5 coincides with the drawing plane.

On its outside, the housing 2 has several outer surfaces. It has in particular a in the axial direction of Vertical axis 5 oriented first outer surface 7 and a respective opposite oriented second outer surface 8. At right angles to the main axis 3, the housing 2 has, in particular, an oblong cross section, which is preferably a rectangular cross section whose longer sides are defined by the first and second outer surfaces 7, 8. The narrow sides of the cross section are oriented in the axial direction of the transverse axis 4 and are exemplarily formed by two opposite lateral outer surfaces 12, 13 of the housing 2, which can be convexly curved to the outside.

In one or in both lateral outer surfaces 12, 13 expediently at least one extending in the axial direction of the main axis 3 mounting groove 14 is formed on which can fix additional components. At least one fastening groove 14 can be used to fasten a position detection device (not shown), with the aid of which, among other things, the relative position of at least one first or second drive unit 24a, 24b, which is still described below, can be detected, which contactlessly detects the position detection device activating actuator 9 may be equipped.

The rotary drive device 1 is expediently subdivided into a drive module 101 and an intermediate position module 102 directly adjoining it in the axial direction of the main axis 3. The subdivision can be purely functional, but preferably also manifests itself in a structural subdivision. By way of example, the housing 2 is subdivided into a first housing section 2 a belonging to the drive module 101 and a second housing section 2 b belonging to the intermediate position module 102, wherein each of these Housing sections may in turn be designed in several parts again.

In the interior of the housing 2, the drive module 101 has two first and second drive spaces 15a, 15b, each having a longitudinal extent. They extend parallel to each other and each have a parallel to the main axis 3 aligned longitudinal axis 16a, 16b.

The two drive spaces 15a, 15b are arranged in the axial direction of the transverse axis 4 at a distance next to one another and expediently separated from each other by an intermediate wall 17 extending between them and in particular belonging to the housing 2. The longitudinal axes 16a, 16b are expediently located in the main plane 6.

Each drive space 15a, 15b has expediently a round and preferably a circular cross-section. It is therefore in particular cylindrical and preferably circular cylindrical drive spaces 15a, 15b.

In the first drive space 15a, the first (24a) of the two above-mentioned drive units 24a, 24b is arranged to be linearly displaceable in the axial direction of the associated longitudinal axis 16a. In a comparable manner, the second drive space 15b receives the second drive unit 24b linearly displaceable in the axial direction of the associated longitudinal axis 16b. The linear movement of the two drive units 24a, 24b, which is also referred to below as a linear drive movement 18, is illustrated in the drawing by a double arrow. It can be caused by controlled fluid admission of the drive units 24a, 24b by means of the above-mentioned fluidic drive medium. Each drive unit 24a, 24b expediently has an elongate drive body 22 with two head sections 25, 26 spaced apart from one another in the axial direction of the associated longitudinal axes 16a, 16b and a rack section 27 extending between the two head sections 25, 26. Each rack section 27 has its own the intermediate wall 17 facing the longitudinal side of a particular rack-like design drive teeth 28, which extends in the axial direction of the main axis 3 of the drive housing 2.

Preferably, each drive toothing 28 consists of a plurality of teeth arranged in a common plane and arranged successively in the axial direction of the longitudinal axis 16a, 16b, which each extend transversely and in particular at right angles to the said longitudinal axis 16a, 16b.

Each drive toothing 28 is expediently an integral part of the associated toothed rack section 27. However, it may also be formed as a separate body and fastened to the toothed rack section 27 by means of any fastening means.

Each head portion 25, 26 carries an annular sealing arrangement 32, via which it is in dynamic sealing contact with the peripheral wall of the respective associated drive space 15a, 15b. In this way, each drive space 15a, 15b is axially subdivided into two working chambers 33, 34, which communicate via an internal fluid channel system 35, indicated only by broken lines, of the housing 2 with connection openings 36 opening out to the outer surface of the housing 2.

The connection openings 36 can be connected for operating the rotary drive device 1 via fluid lines (not shown) with the interposition of a control valve device with a pressure source supplying the drive medium. By appropriate actuation of the control valve device, the working chambers 33, 34 can be fluid-loaded or relieved of pressure in such a coordinated manner that the two drive units 24a, 24b execute synchronous opposing drive movements 18.

The drive movements 18 of the two drive units 24a, 24b, which can be brought about by controlled application of fluid, are converted by gear means 37 of the rotary drive device 1 into an output rotary movement 43 of an output unit 38. The direction of rotation of the output rotational movement 43 depends on the linear movement direction of the drive units 24a, 24b and takes place optionally in a clockwise or counterclockwise direction. By the drive units 24a, 24b are driven to a reciprocating linear motion, can be tapped on the output unit 38, an oscillating output rotary motion 43.

The output unit 38 can be rotated in the context of its output rotational movement between two rotational end positions. By way of example, an angle of rotation of 180 ° is also present between these two rotational end positions, which are also referred to below as the first rotary end position and as the second rotary end position. The FIGS. 8 and 3 illustrate the first rotational end position, the Figures 10 and 5 the second rotary end position. Both rotary end positions are predefined by end stop means 55 of the rotary drive device 1, which are expediently effective between the housing 2 and the two drive units 24a, 24b.

By way of example, the end stop means 55 per drive unit 24a, 24b comprise an end stop unit 56a, 56b which are fixed on the housing 2 on the side of the drive units 24a, 24b opposite the intermediate position module 102. A first end stop unit 56a is arranged in coaxial extension of the first drive unit 24a, a second end stop unit 56b in coaxial extension of the second drive unit 24b. At each Endanschlageinheit 56a, 56b one of the associated drive unit 24a, 24b entgegenragende end stop surface 57a, 57b is arranged, on which the drive unit 24a, 24b impinges with its drive body 22 for specifying a Hubendlage.

In the out Figures 3 and 8th Resulting operating situation is a basic position of the rotary drive device 1, in which the first drive unit 24a is positioned by abutment against the end stop surface 57a of the first Endanschlageinheit 56a in its first stroke end position. Due to the drive-driven coupling via the transmission means 37, the second drive unit 24b assumes a second stroke end position lifted off from its associated end stop surface 57b. The output unit 38 is in this case in its first rotational end position.

In the out Figures 5 and 10 apparent operating state, both drive units 24a, 24b in their respect FIG. 3 shifted in each case opposite stroke end position, in which case the drive body 22 of the second drive unit 24b abuts against the end stop surface 57b of the second Endanschlageinheit 56b, so that the first Hubendstellung the second drive unit 24b is defined. Due to the transmission coupling via the transmission means 37, the second drive unit 24b here assumes a second stroke end position remote from its associated end stop surface 57a.

Thus, in the embodiment, the second Hubendlagen the drive units 24a, 24b respectively not directly determined by cooperation with Endanschlagmitteln, but indirectly, through the intermediary of the gear means 37, by taking a first Hubendlage each aban an Endanschlageinheit 56b, 56a adjacent other drive unit 24b, 24a ,

It is expedient if the end stop means 55, as is the case in the exemplary embodiment, are realized in the form of fluidic shock absorber means. By way of example, each end stop unit 56a, 56b is formed by a fluidic, for example a pneumatic or a hydraulic shock absorber. The shock absorber means ensure that the impact force of the drive units 24a, 24b is damped in their stroke end positions.

In order to be able to grasp the output rotary motion 43 conveniently, the output unit 38 is expediently equipped with at least one fastening interface 42, which is represented by a plurality of fastening holes as an example and on which an external component, which in particular can be rotationally moved, can be fastened in a particularly detachable manner. The external component is, for example, a gripping device belonging to a handling device.

As in particular from FIG. 2 it can be seen, the output unit 38 may be rotatably supported on the housing 2 with the interposition of a relative to her and with respect to the housing 2 separate bearing ring 44. By the pivot bearing a rotation axis 45 is defined for the output rotary motion 43, which is suitably rectified with the vertical axis 5. Expediently, the output unit 38 has a arranged in the region of the first outer surface 7, in Substantially disk-shaped driven plate 46, which is concentrically enclosed by the bearing ring 44 and on which the fastening interface 42 is located. Between the driven plate 46 and the bearing ring 44 rolling bearing means 62 are suitably arranged.

The output unit 38 expediently also includes a projecting into the housing 2 output shaft 47 which carries a driven ring gear 48 in concentric arrangement, which is located on the outer circumference of the output shaft 47 and expediently extends around the output shaft 47 around. It is designed in particular in the manner of a toothed wheel or pinion and in particular has a straight toothing, wherein its teeth are aligned parallel to the axis of rotation 45.

The output unit 38 dives with its driven sprocket 48 between the two drive units 24a, 24b and communicates with the drive teeth 28 in simultaneous meshing engagement. In this way, the driven sprocket 48 is a part of the transmission means 37, wherein a linear movement of the drive units 24a, 24b has the consequence that the driven sprocket 48 and thus the entire output unit 38 is driven to the output rotational movement 43 about the axis of rotation 45.

Notwithstanding the embodiment, the rotary drive device 1 may also contain only a single drive unit, so that the output gear ring 48 meshes with only one drive toothing 28. The dual arrangement of drive units 24a, 24b, however, allows the generation of higher torques.

In addition to the bearing ring 44, the output unit 38 can also be supported rotatably with respect to the housing 2 via a further rotary bearing device 84 axially spaced relative to the bearing ring 44.

The rotary drive device 1 is equipped with a position setting device 52, which is realized in the embodiment with the cooperation of the intermediate position module 102. The position setting device 52 makes it possible to specify at least one rotational intermediate position of the output unit 38 lying between the two rotational end positions. By way of example, the position setting device 52 advantageously allows the specification of two different rotational intermediate positions, which is related to the fact that one of the drive units 24a, 24b in each case participates in the specification of one of the two rotational intermediate positions. However, such functionality is not mandatory. The position setting device 52 can also be designed so that, despite the presence of two drive units 24a, 24b, only one rotary intermediate position of the output unit 38 can be predetermined.

An advantage of the position setting device 52 is that the possible with their help specification of at least one rotational intermediate position is optional. The position setting device 52 is thus also deactivated so far that the output unit 38 is continuously rotated between its two rotational end positions, without inserting a stopover at a rotational intermediate position.

The position setting device 52 has two stop units 58a, 58b, wherein a first stop unit 58a is functionally associated with the first drive unit 24a and a second stop unit 58b with the second drive unit 24b cooperates. The two stop units 58a, 58b are expediently arranged in each case in coaxial extension of the respectively respectively cooperating first and second drive unit 24. Each stop unit 58a, 58b is located in the linear travel of the associated drive unit 24a, 24b, but is linearly movable relative to the housing 2 in the axial direction of the main axis 3. This movement of the stop units 58a, 58b will be referred to below as the positioning movement 63.

Each stop unit 58a, 58b is capable of preventing the drive unit 24a, 24b arranged in the axial extension thereof, that is to say the respectively functionally associated drive unit 24a, from reaching its second stroke end position. For this purpose, the relevant stop unit 58a, 58b is positioned in a stop position taken with respect to the housing 2 in the context of a positioning movement 63 and mechanically releasably mechanically locked in this stop position by a locking device 64 formed as part of the position setting device 52 such that it is prevented from further positioning movement 63 , The stop unit 58a, 58b can thus not be displaced by the drive unit 24a or 24b impinging on it, so that the drive unit 24a, 24b is stopped in a stroke intermediate position predetermined by the locked stop position. This stroke intermediate position, in turn, corresponds to a rotational intermediate position of the output unit 38 due to the slip-free drive coupling effected by the transmission means 37.

When the stopper unit 58a or 58b locked in the stopper position is unlocked, it can be displaced out of the stopper position by the drive unit 24a or 24b acting on it so that it no longer satisfies the position setting function and the drive unit which is no longer locked 24a and 24b can continue to move to the second stroke end position, in which the output unit 38 assumes the second rotational end position.

In the following, a particularly advantageous construction of the position specification device 52 and its components will be described with reference to the exemplary embodiment.

In coaxial extension to each drive space 15 a, 15 b, a parallel to the main axis 3 extending elongated recess is formed in the housing 2, which is referred to as a positioning chamber, hereinafter referred to in individual naming the alignment with the first drive chamber 15 a positioning as a first positioning chamber 65 a and with the second drive chamber 15b aligned positioning is designated as the second positioning chamber 65b. Both positioning chambers 65a, 65b are preferably formed in the second housing section 2b. In the first positioning chamber 65a, the first stop unit 58a extends in the second positioning chamber 65b, the second stop unit 58b. Each stop unit 58a, 58b is received in the associated positioning chamber 65a, 65b axially displaceable by performing the positioning movement 63.

Corresponding to the parallel arrangement of the two drive units 24a, 24b, the two positioning chambers 65a, 65b are also at the same axial height with respect to the main axis 3, wherein each positioning chamber 65a, 65b has a longitudinal axis 66a or 66b and these longitudinal axes 66a, 66b are expediently located in the Main level 6 run.

The positioning chambers 65a, 65b are fluid-tightly separated from the drive spaces 15a, 15b. An intermediate wall 67 of Housing 2 extends transversely to the main axis 3 between on the one hand the two positioning chambers 65a, 65b and on the other hand the two drive spaces 15a, 15b.

Each drive unit 24a, 24b has an abutment surface 68 oriented axially in the direction of the associated drive unit 24a, 24b, which axially faces a counter-abutment surface 69 belonging to the associated drive unit 24a, 24b. When an abutment unit 58a or 58b is locked in its stop position, the associated drive unit 24a, 24b, which is moved in the direction of its second stroke end position, is stopped by the cooperation of the stop surface 68 and the counter stop surface 69 before reaching this second stroke end position. The stop position is the intermediate stroke position mentioned above.

The stopping of the drive movement 18 of a drive unit 24a, 24b causing cooperation of a stop surface 68 and a counter-abutment surface 69 may consist in that the drive unit 24a, 24b with the counter stop surface 69 directly on the stationary by the locking device 64 relative to the housing 2 fixed stop surface 68 impinges , In the embodiment, however, a more advantageous indirect interaction between abutment surface 68 and counter-abutment surface 69 is realized by between the two surfaces 68, 69 a relative to both surfaces 68, 69 in the axial direction of the longitudinal axis 66a, 66b movable intermediate member is incorporated, that of a movable shock absorber member 72 of a fluidic shock absorber 73a and 73b is formed.

When a drive unit 24a, 24b approaches the intermediate stroke position to be preset by the position setting means 52, it encounters its counter stop surface 69 after bridging an axial gap 74 on the facing end surface 104 of the shock absorber member 72, which is spaced at this time by a Stoßdämpfabstand "s" of the stop surface 68. Upon further movement of the drive unit 24a, 24b pushes selbige the shock absorber member 72 in front of him until it hits the stop surface 68 under specification of the intermediate stroke position. The distance traveled by the shock absorber member 72 to impact on the abutment surface 68 and formed by the Stoßdämpfabstand "s" distance defines a damping distance, while the by the known function of the fluidic shock absorber 73a, 73b a decelerating or damping acting fluid counterforce is established which decelerates the associated drive unit 24a, 24b and thereby dampens their final impact upon reaching the intermediate lift position.

Each stop unit 58a, 58b includes a counter-latching member 75 slidably guided relative to the housing 2 in the associated positioning chamber 65a, 65b for carrying out the positioning movement 63 in the axial direction of the main shaft 3. One or more annular or sleeve-shaped guide elements 76 located on the inner circumference of each positioning chamber 65a, 65b fixed axially immovably, enclose the counter-locking member 75 in such a way that the latter, although axially displaceable, but is supported in the radial direction.

The counter-locking member 75 carries on the one hand the stop surface 68 and on the other hand, that component of the stop unit 58a, 58b, which is mechanically locked by the locking device 64.

With regard to the possibility of locking, the counter-locking member 75 has on its outer circumference a locking recess 77 extending radially with respect to the associated longitudinal axis 66a, 66b and open radially outwards. The locking recess 77 is formed in particular by a concentrically arranged on the outer circumference of the counter-locking member 75 annular groove. The locking recess 77 has a locking flank 78 oriented in the axial direction of the main axis 3, which is oriented in the axial direction in which the stop unit 58a, 58b to be stopped moves when it is displaced in the direction of its second stroke end position. In other words, the locking edge 78 is oriented in the opposite direction as the stop surface 68.

The locking device 64 expediently has a separate locking unit 64a, 64b for each stop unit 58a, 58b. In this case, a first locking unit 64a of the first stop unit 58a and a second locking unit 64b of the second stop unit 58b assigned. Each locking unit 64a, 64b is arranged in the region of the peripheral outer periphery of the associated stop unit 58a, 58b, in particular in the region of the outer circumference of the respective counter-locking member 75.

Each locking unit 64a, 64b has a locking member 82 which is constantly supported relative to the housing 2 in the axial direction of the main shaft 3 and which is transverse and in particular perpendicular to the main shaft 3 relative to the housing 2 and also relative to the associated stop unit 58a, 58b with respect to its counter-locking member 75 controlled is movable.

By way of example, the housing 2 has at its second housing section 2b two receiving recesses 83 extending at right angles to the main axis 3, which are each open to an outer side of the housing 2 and which each pass through one of the two positioning chambers 65a, 65b. By way of example, the two receiving recesses 83 lead to one of the two mutually oppositely oriented lateral outer surfaces 12, 13.

In each receiving recess 83, one of the locking members 82 is guided linearly displaceable, so that it can perform at 85 indicated by a double arrow linear working movement 85, whose direction is oriented in particular radially with respect to the associated counter-locking member 75.

When an abutment unit 58a, 58b assumes its stop position, the associated locking member 82 can be displaced in the context of the linear working movement 85 between an engaging into the locking recess 77 of the counter-locking member 75 locking position and a retracted from this locking recess 77 release position. The Figures 3 . 5 and 6 show a state in which the locking member 82 of the first locking unit 64a, the locking position and the locking member 82 of the second locking unit 64b occupies the release position.

In the locking position, the locking member 82 immersed in the locking recess 77 such that its locking edge 78 is supported on a facing side surface of the locking member 82.

Preferably, the locking member 82 has a counter-locking member 75 like a frame enclosing shape. It may have a cylindrical outer periphery over which it is slidably in contact with the wall of the associated receiving recess 83 for enabling the working movement 85.

Preferably, the locking member 82 is axially penetrated by a through hole 86, whose cross-sectional area is greater than the outer cross section of the counter-locking member 75 in that area which is axially adjacent to the drive body 22 side facing the recess recess 77.

The stop position of each stop unit 58a, 58b is predetermined in that the stop unit 58a, 58b bears against a housing-fixed position specification surface 87, which is oriented in the same axial direction as the locking sidewall 78. Preferably, the position setting surface 87 is located on the positioning chamber 65a, 65b To specify the stop position, the stop unit 58a, 58b, in particular with one of the intermediate wall 67 facing end face of its counter-locking member 75, abut the position input surface 87.

Starting from the stop position defined in this way, the stop unit 58a, 58b can be moved with the locking unit 64a, 64b unlocked while the positioning movement 63 is carried out in the direction of removal from the positioning surface 87. In this case, the direction of movement coincides with that direction of movement in which the drive unit 24a, 24b moves on its way in the direction of the second stroke end position. Each locking member 82 is movable in an individually controllable manner between its locking position and its release position.

By way of example, each locking unit 64a, 64b has a preferably mechanical spring device 92, by which it is constantly biased in the direction of the locking position. The spring device 92 is supported on the one hand on the locking member 82 and on the other hand directly or indirectly on the housing 2 from. By way of example, an indirect housing-side support is chosen, in that the spring device 92 bears against a cover element 93 which closes the open opening of the receiving recess 83 and which is fixed on the housing 2 by a securing ring 91 or in some other way. The cover member 93 may be part of a manual override device useful for manual actuation of the latch member 82.

For the need-controlled switching and holding a locking member 82 in the or in the release position, the locking member 82 is operatively connected to a Fluidbeaufschlagungsfläche 94 which delimits a formed in the interior of the housing 2 actuating space 95 in a movable manner. By way of example, the fluid loading surface 94 is part of a drive piston 96, which is drivingly coupled to the locking member 82 or may be formed directly from the locking member 82. Each Fluidbeaufschlagungsfläche 94 individually limits a separate operating space 95, which can be acted upon via a turn individual, in the drawing only dotted out indicated control channel 97 from the outside with a fluidic pressure medium or depressurized. Both control channels 97 expediently open to an outer surface of the housing 2, from where they are not in further manner shown with a controlled fluid admission controlling control valve means are connectable.

To move a locking member 82 in the release position and also to hold there, the associated operating space 95 is supplied with pressure medium, which provides a sufficiently high actuation force to overcome the restoring force of the associated spring means 92. To switch back to the locking position, a pressure relief of the operating chamber 95 is sufficient, so that the restoring effect of the associated spring device 92 comes into their own.

The counter-locking member 75 expediently has a cavity 89 which is axially open in the direction of the drive unit 24a, 24b cooperating therewith or in the direction of its drive body 22. This cavity is in particular realized in that the counter-locking member is sleeve-shaped, wherein its interior forms the said cavity.

Each drive unit 24a, 24b has a preferably rod-shaped stop ram 90 which is fixed at one end to the drive body 22 and extends axially from the drive body 22 in the direction of the coaxially adjoining stop unit 58a, 58b. Here, the stopper ram 90 passes through the drive space 15a, 15b of the subsequent positioning chamber 65a, 65b separating partition 67 and projects into the relevant positioning chamber 65a, 65b. The passage of the stopper plunger 90 through the intermediate wall 67 takes place in a displaceable and at the same time sealed manner. For this purpose, in the penetrated by the stop ram 90 opening of the intermediate wall 67 may be mounted a sealing ring.

The stopper plunger 90 is screwed in the embodiment with its the drive body 22 facing end portion in a threaded bore of the drive body 22. However, another type of attachment is also possible. Also, the stopper ram 90 may readily be integrally connected to the drive body 22.

In one embodiment, not shown, the stopper plunger 90 is a not fixedly connected to the drive body 22 component, so that it can be acted upon by the drive body 22 only sliding and the return movement is caused in other ways.

The end face of the stop plunger 90 opposite the drive body 22 expediently forms the counterstop surface 69 already mentioned above. Overall, the axial length of the stop plunger 90 is chosen such that it is constantly in the position independent of the relative position between the drive body 22 and the counter-locking member 75 Cavity 89 of the counter-locking member 75 is immersed.

It is advantageous if the stop ram 90 is guided linearly displaceably by the stop unit 58a, 58b, so that it assumes a stable position at right angles to the longitudinal axis 16a. The linear guide is expediently characterized in that the stop ram 90 is enclosed by at least one guide bush 98 slidable, which is fixed on the inner circumference of the cavity 89 delimiting wall of the counter-locking member 75. Conveniently, at least two axially spaced guide bushes 98 per stop ram 90 are present.

In the region of its rear end section 99 axially opposite the associated drive unit 24a, 24b, the counter-locking member 75 expediently carries one of the already mentioned fluidic shock absorbers 73a, 73b. Each fluidic shock absorber 73a, 73b has a shock absorber housing 100, with which it is screwed, expediently in an axially adjustable manner, in the rear end portion 99 of the counter-locking member 75. He is placed in coaxial extension of a stopper plunger 90.

The abovementioned shock absorber member 72 protrudes inside the cavity 89 on the front side of the fluidic shock absorber 73a, 73b and opposes the counterstop surface 69.

The shock absorber member 72, which consists for example of a plunger and a displacer, has a front end surface 104 facing the abutment surface 69 and, moreover, a rear end surface 105 disposed in the interior of the shock absorber housing 100, the latter facing the abutment surface 68. The stop surface 68 is in particular a component of the shock absorber housing 100 and is exemplarily inside the shock absorber housing 100.

A drive unit 24a, 24b is then in a stroke-intermediate position corresponding to a rotary intermediate position, when it rests with its arranged on the stopper plunger 90 counter-abutment surface 69 on the facing front end surface 104 of the shock absorber member 72 and the same until it abuts against the stop surface 68 in the Shock housing 100 has pushed. The counter-locking member 75 is locked in the housing firmly taking the stop position by the associated locking unit 73a, 73b.

The predetermined by the stop position stroke intermediate position and thus also the resulting rotational intermediate position are expediently variably predetermined. To change the intermediate stroke position, the fluidic shock absorber 73a, 73b can expediently be arranged and fixed in different axial relative positions with respect to the counter-locking member 75. By way of example, the adjustment can take place by screwing or unscrewing the shock absorber housing 100 into the counter-locking member 75 or from the counter-locking member 75. For fixing the position thus adjusted, for example, a screwed onto the shock absorber housing 100 and with the rear end face of the counter-locking member 75 braced lock nut 106 can be used.

As an alternative to the exemplary embodiment, the stop surface 68 may also be arranged on the shock absorber housing 100.

In one embodiment, not shown, of the rotary drive device 1, the stop unit 58a, 58b no shock absorber 73a, 73b, so that the stop surface 68 is formed in particular directly on the counter-locking member 75 or on a fixed to the counter-locking member 75 stop body.

If necessary, a drive unit 24a, 24b stopped in a stroke intermediate position can be moved further into the second stroke end position by switching the locking member 82 out of the locking position which positively locks the assigned stop unit 58a, 58b into the release position. In this way, the stop surface 68 is no longer fixed to the housing fixed and can yield under the thrust of the counter-attack surface 69 acting on them. The unlocked stop unit 58a or 58b then moves to perform a positioning movement 63 together with the no longer blocked drive unit 24a or 24b, until the latter has reached the second Hubendlage. At the transition between the intermediate stroke position and the second end of stroke position, the relevant drive unit 24a or 24b and the associated stop unit 58a, 58b thus form a movement unit.

When the stop unit 58a, 58b has been displaced out of the stop position by the stop unit 58a, 58b moved into the second stroke end position, it assumes an inoperative axial position. Here, its locking recess 77 is displaced relative to the stationary on the housing 2 remaining locking member 82.

In order for an abutment unit 58a, 58b, which has been displaced into the inoperative axial position, to be able to specify an intermediate rotational position during a subsequent operating cycle of the rotary drive device 1, each stop unit 58a, 58b is associated with drive means 107, which make it possible to provide Unlocked stop unit 58a, 58b from the inoperative axial position to reset their stop position.

An abutment unit 58a, 58b can only be returned from its inoperative axial position to the stop position if the drive unit 24a or 24b cooperating with it is or has been moved back into the intermediate stroke position and preferably into the first stroke end position at the same time or earlier.

By way of example, the drive means 107 per stop unit 58a, 58b comprise a motion-coupled to the stop unit 58a, 58b and in particular firmly connected drive piston 108. Preferably, the drive piston 108 is a component of the counter-locking member 75th

The drive piston 108 is received displaceably guided in the associated positioning chamber 65a, 65b under sealing. It limits an operating space 109, which is a partial space of the positioning chamber 65a, 65b and which is limited on the drive piston 108 axially opposite side by a housing-fixed boundary wall 110. The actuation space 109 is located on the side of the drive piston 108 which faces away axially from the associated drive body 22.

Each actuation space 109 communicates with an individual actuation channel 111 which is suitable for controlled fluid admission and which is expediently part of the above-described fluid channel system 35.

If a pressure medium is fed into the associated actuating chamber 109 via the assigned actuating channel 111, the associated drive piston 108 experiences a positioning force in the direction of the stop position. Therefore, the stopper unit 58a, 58b can be moved back to the stop position when the driving unit 24a, 24b aligned therewith permits.

The actuating chambers 109 are expediently integrated into the fluid channel system 35 such that a stop unit 58a or 58b is always fluidly acted upon by its drive piston 108 in the direction of the stop position if the associated drive unit 24a, 24b simultaneously drive in the direction of the first stroke end position performs. This ensures that an abutment unit 58a, 58b is available for specifying a rotary intermediate position when a stop unit 58a or 58b is in the first stroke end position.

Deviating from the exemplary embodiment, an implementation form would also be possible for the drive means 107, for example, in which each stop unit 58a, 58b is moved back directly into the stop position by the associated drive unit 24a, 24b. This can be achieved for example by friction and / or by a Verrastungsfunktion.

If, as in the exemplary embodiment, each drive unit 24a, 24b is assigned its own stop unit 58a, 58b, it is possible to define a rotational intermediate position in each direction of rotation of the output unit 38. By way of example, an in FIG. 9 illustrated first rotational intermediate position can be specified when the output unit 38 from the in FIG. 8 shown first rotational end position moves toward its second rotational end position. Furthermore, an in FIG. 11 illustrated second rotational intermediate position can be specified when the output unit 38 from the in FIG. 10 shown second rotational end position in the direction of the first rotational end position moves.

In all cases, it is possible to continue rotating the output unit 38 after a temporary stop in a rotary intermediate position either with the same direction of rotation or with the opposite direction of rotation. In this way, there is a high degree of flexibility in the specification of different rotational positions.

The rotational angles of the output unit assumed in the two rotational intermediate positions depend on the design of the respective Stop unit 58a, 58b and can easily differ from each other. Among other things, this is facilitated by the fact that the two stop units 58a, 58b are movable relative to the housing 2 independently of one another and are also releasably mechanically lockable independently of one another in their respective stop position.

It is also advantageous that the two locking members 82 of the locking device 64 are independently operable so that they do not affect each other in their function. Nevertheless, with a corresponding design, it would nevertheless be possible to kinematically positively couple the two locking members 82, so that they alternately occupy, for example, their respective locking position and release position.

If no rotational intermediate position is desired, the output unit 38 can be rotated without intermediate stop between its two rotational end positions. For this purpose, only the locking member cooperating with the associated stop unit 58a, 58b is to be switched over in good time to the release position.

Claims (15)

A fluid operated rotary drive apparatus comprising: a housing (2), a driven unit (38) rotatably mounted with respect to the housing (2) and rotatable between two rotational end positions by executing a rotary output movement, - At least one in a drive space (15a, 15b) of the housing (2) arranged and controlled by fluid application to a in the axial direction of a main axis (3) of the housing (2) oriented linear drive movement (18) between two Hubendlagen drivable drive unit (24a, 24b ), which is coupled for generating the rotary output movement via gear means (37) with the output unit (38), - And a position setting means (52) having at least one in the travel of at least one drive unit (24a, 24b) arranged stop unit (58a, 58b) which is movable in the axial direction of the main axis (3) relative to the housing (2) and the default at least one between the two rotational end positions lying rotational intermediate position of the output unit (38) in a reaching a Hubendlage the associated drive unit (24a, 24b) preventing stop position relative to the housing (2) is releasably blockable, characterized in that said position setting means (52) includes a locking means (64) provided over at least one relative to said housing (2) in the axial direction of the main axis (3) and transverse to said main axis (3) relative to both the housing (2). and the stop unit (58a, 58b) controlled movable locking member (82) which is for blocking the stop position of at least one stop unit (58a, 58b) in a releasable mechanical locking engagement with the stop unit to be blocked (58a, 58b) movable at least one drive unit (24a, 24b) by its fluid loading relative to the previously locked in a stop position stop unit (58a, 58b) from a Hubendlage in a by the locked stop unit (58a, 58b) defined and the intermediate rotational position predetermining intermediate stroke position movable is. Rotary drive device according to claim 1, characterized in that the gear means (37) comprises a driven sprocket (48) arranged on the output unit (38) and a rack-like drive toothing (28) engaging the output sprocket (48) on each drive unit (24a, 24b). contain. Rotary drive device according to claim 1 or 2, characterized in that in the housing (2) arranged side by side and in opposite directions linearly driven drive units (24a, 24b) are arranged, both of which are motion-coupled via the transmission means (37) with the output unit (38). Rotary drive device according to claim 3, characterized in that the position setting device (52) has two respective one of the drive units (24a, 24b) functionally associated stop units (58a, 58b) which are independently relative to the housing (2) movable and by the locking device (64) are releasably mechanically locked in each case in at least one stop position. Rotary drive device according to claim 4, characterized in that the locking device (64) has two independently operable and each one of the stop units (58a, 58b) functionally associated locking members (82). Rotary drive device according to one of claims 1 to 5, characterized in that the at least one stop unit (58a, 58b) is arranged in coaxial extension of the drive unit cooperating with it (24a, 24b). Rotary drive device according to one of claims 1 to 6, characterized in that each stop unit (58a, 58b) in the axial direction of the main axis (3) relative to the housing (2) slidably guided counter-locking member (75), with which the locking member (82 ) can be brought into locking engagement for the positive fixing of the stop position and which carries a stop surface (68) which can interact with the drive unit (24a, 24b) when the locked stop position is taken in such a way that this drive unit (24a, 24b) Intermediate position of the output unit (38) corresponding and lying between the two possible Hubendlagen intermediate stroke position is stopped. Rotary drive device according to claim 7, characterized in that the counter-locking member (75) carries a fluidic shock absorber (73a, 73b) having a in the axial direction of the main axis (3) movable shock absorber member (72) in the path of the associated drive unit ( 24a, 24b) protrudes. Rotary drive device according to claim 8, characterized in that the stop surface (68) is a component of the fluidic shock absorber (73a, 73b) and in particular with the shock absorber member (72) cooperates, such that the associated drive unit (24a, 24b) with the interposition of the shock absorber member (72) is indirectly stoppable by the stop surface (68) in the intermediate stroke position. Rotary drive device according to one of claims 7 to 9, characterized in that the counter-locking member (75) has an axially open towards the associated drive unit (24a, 24b) cavity (89) into which a with the drive unit (24a, 24b ) motion-coupled and in particular as a fixed part of the drive unit (24a, 24b) formed stop plunger (90) is immersed - in particular the front side - for cooperation with the stop surface (68) formed counter-abutment surface (69). Rotary drive device according to claim 10, characterized in that the stop ram (90), regardless of the between the drive unit (24a, 24b) and the stop unit (58a, 58b) occupied relative position constantly in the cavity (89) of the counter-locking member (75) dips , wherein it is expediently guided in a linearly displaceable manner by the counter-locking member (75) in the interior of the cavity (89). Rotary drive device according to claim 10 or 11, characterized in that the counter-locking member (75) is sleeve-shaped, wherein it expediently one of the drive unit (24a, 24b) facing the front end portion and a related thereto, with an axially adjustable fluidic shock absorber (73a , 73b) has equipped rear end portion (99). Rotary drive device according to one of claims 1 to 12, characterized in that the at least one stop unit (24a, 24b) axially displaceable in a in the housing (2) formed and from the at least one drive space (15a, 15b) fluid-tight separated positioning (65a , 65b), wherein their drive means (107) are assigned, by means of which it can be moved to the stop position when the locking engagement is released. Rotary drive device according to claim 13, characterized in that the drive means (107) comprise a drive piston (108), which is coupled to the stop unit (58a, 58b) and delimits an actuation space (109) which can be subjected to fluid actuation in order to move the stop unit (58a, 58b) is. Rotary drive device according to one of claims 1 to 14, characterized in that the at least one locking member (82) between a locking engagement with the stop unit (58a, 58b) causing locking position and a stop unit (58a, 58b) releasing the axial release position can be switched wherein the switching is suitably evacuated by controlled fluid loading.

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