DE102018108609A1 - Working cylinder device with at least one working cylinder unit with mechanical position assurance and retrofitted under load rod emergency seal and method for their operation - Google Patents

Abstract

In order to mechanically secure at a working cylinder device (100) with at least one working cylinder unit (50), in which the reached position of extension of the piston rod (22, 22 '), even under load and mechanically secured working cylinder unit (50) in case of failure of the rod seals (33) loosen the mechanical fuse and retract the piston rod (22, 22 '), in the rod seal sleeve (29) an open towards the inner circumference annular space (40) is provided in If necessary from the free end of an emergency seal (37) can be introduced and pressed. For this purpose, the rod seal sleeve (29) is formed in two parts in the axial direction with a separation in the axial region of the annular space (40).

Description

The invention relates to a working cylinder device with at least one working cylinder unit, also called piston-cylinder units, which has a cylinder with a substantially closed cylinder base and a dense axially guided therein piston. Between the cylinder bottom and the piston thus a first pressure chamber is present, which can be acted upon by a pressurized working fluid, which is supplied via a pressure chamber port, which is often located in the cylinder bottom.

These power cylinder units are used with different working media - for example as a hydraulic cylinder or as a pneumatic cylinder - to perform linear movements. In this case, the piston rod protrudes out of the cylinder, even in the fully retracted position of the piston, and can be connected with its free end with a part to be moved, for example a load to be lifted.

There are two types of construction:

Piston with piston rod:

On the side facing away from the cylinder bottom of the piston, a piston rod fixedly connected to the piston extends axially partially out of the cylinder, which has a smaller cross-section than the piston. The piston has only a relatively short compared to the axial length of the cylinder interior piston sealing surface, which is in all Ausfahrzuständen in the cylinder. This short piston sealing surface travels sealingly axially relative to the cylinder sealing surface, which extends substantially over the entire length of the cylinder interior, which must be formed as a smooth cylinder sealing surface.

The free end of the cylinder generally has in addition an annular, applied to the outer circumference of the piston rod scraper to prevent ingress of foreign bodies between the outer periphery of the piston rod and the cylinder inner surface.

If this scraper is another sealing surface, this results in between this further sealing surface and the piston in the cylinder, a second pressure chamber, which can be acted upon separately from the first pressure chamber with a pressurized working fluid, so that a double, so controlled in two axial directions movable, Working cylinder unit is present.

Piston = piston rod, plunger:

The cylinder has only a relatively short, compared to the axial length of the cylinder interior, so-called rod sealing surface at the open, front end of the cylinder in the form of an inner circumferential surface, while over the remaining length of the cylinder has a contrast larger inner diameter.

The piston acts as the piston rod itself, which has about as compared to the axial length of the cylinder interior, just as long, smooth piston sealing surface in the form of its outer circumferential surface on which the short rod sealing surface of the cylinder is always sealing, while over the remaining length of the inner circumferential surface of the cylinder maintains a radial distance to the concentric piston sealing surface extending therein. If necessary, therefore, the free, inner end of the piston rod - which acts as a displacement body, ie plunger, when entering the cylinder - must be guided by additional measures in the cylinder cross-section.

Due to the design, there is thus usually only a first pressure chamber in this design, so that such a working cylinder unit can be acted upon only on one side with working medium, whereby an axial outward movement of the piston rod is effected.

The present application relates to this second design, which operates on the positive displacement principle and which is referred to as Plungertyp.

II. Technical background

Depending on the intended use, it may be necessary, especially for safety reasons, to reach the extended position of the piston rod relative to the cylinder not only by providing the necessary pressure in the pressure chamber of the cylinder, but additionally to provide a mechanical, frictional or positive locking of the cylinder Axial position of the piston rod is present, if possible at any extension position, that is stepless, or at least in individual stages with the smallest possible distances from one stage to the next.

If the working cylinder unit is multi-stage telescopic, of course, such a mechanical position assurance is present on each telescopic stage.

This is especially necessary when the power cylinder unit is used for lifting and subsequent support of an object in the raised state, possibly for longer time during which the pressure booster should be able to be switched off.

A typical case is the use of such, usually multi-stage, working cylinder unit as a lifting device for the horizontal lifting of an aircraft, for example, if this must be extensively serviced or the chassis must be tested or repaired in the unloaded condition.

Then at least three for lifting, usually in addition a fourth for support and horizontal position assurance, such working cylinder units are used together as a working cylinder device at different points of the aircraft, each one working cylinder unit is installed in a so-called. Tri-pod , So for the purpose of preventing tipping with three radially abstrebenden support struts equipped support frame.

In known solutions, a self-locking safety thread is applied as a mechanical fuse in each working cylinder unit on the outer circumference of the piston rod on which a meshing locking nut can be moved axially by screwing, which must be constantly manually updated by a helper, or with great effort electromotive drive of the lock nut and distance sensor via a control automatically up to an equidistant gap during operation must be adjusted continuously.

As a result, lifting and jacking up an airliner usually takes well over an hour, while a team of up to seven men are needed solely for manual, synchronous tracking of lock nuts, as well as communication, monitoring, backup and service.

Apart from that, the fact that the safety thread is located on the outer circumference of the piston rod, and in the permanently open annular gap between securing external thread and the sliding head restraint guide to move the threaded rod uncontrolled dirt, corrosion-resistant grease of the threaded rod, water and moisture penetrate and if the piston seal leaks, leaking oil from the oil pressure space below the piston can escape into the clearance above the piston, leading to significant disadvantages and unpredictable, unpredictable risks, which are described below.

With increasing operating time there is the increasing risk that in the inner tube on the free piston surface, especially in the sealed by a piston seal against the oil pressure space gap between the piston and tube inner wall, especially at long standstill in an upscale, consistent position, solids and dried dirt can cake so that they cause uncontrollable and inaccessibility without possibility of damage-free removal or cleaning when lifting grooves in the cylinder inner surface and the piston seal is destroyed either directly by mechanically pulling the stuck tightly on the cylinder inner wall foreign bodies or by cutting the grooves.

This unknown, directly uncontrollable risk of unpredictable total failure of the hydraulic seal of the hydraulic pressure required to hydraulically raise the threaded rod below the piston can cause the aircraft, possibly held in a raised position by the locknut for a long time, to cease to exist can be drained down. For this purpose, namely first a hydraulic pressure build-up for lifting the load and releasing the frictional and positive locking of the lock nut is imperative so that the then unloaded lock nut is free and can be turned back in the subsequent hydraulic lowering of the threaded rod while maintaining a distance gap.

If the piston seal fails to rebuild the pressure in the oil pressure chamber, so that the load can no longer be lifted due to the leak, the lock nut will remain firmly seated due to insurmountable frictional engagement. Thus, the mechanical position assurance can not be repealed, and the aircraft must then be recovered with great effort using mobile cranes. The main risk on the one hand in the large, "soft" distribution of the lifting load by loops under the not intended for point load aircraft outer surfaces and on the other hand in the difficult synchronization of the downward movement of the cranes with the other still functioning tripod lifts.

In any case, it must be ensured that the lightweight structure of the aircraft pressure cell is not damaged by uneven, even dynamically caused, uneven load distribution. Since no aircraft manufacturer guarantees for such unconventional salvage actions, in such cases there is the unpredictable risk of total loss due to irreparable structural damage to the aircraft.

III. Presentation of the invention

Technical task

It is therefore an object of the invention to provide a power cylinder apparatus having at least one power cylinder unit with a mechanical fuse for the instantaneous axial position of the piston rod and a method of operating such a power cylinder apparatus which provides for subsequent sealing of the rods -Sealing unit relative to the under load, mechanically secured in its extended position, piston rod allows the working cylinder device.

Solution of the task

This object is solved by the features of claims 1 and 12. Advantageous embodiments will be apparent from the dependent claims.

With regard to the working cylinder device and in particular its working cylinder unit is known such a working cylinder unit constructed according to the plunger principle that at the front end frontally open and at the rear end by a cylinder bottom substantially closed or at least closable cylinder at the front, open end of the cylinder interior having a rod sealing unit with a rod sealing sleeve, in whose inner peripheral surface at least one annular circumferential seal, the so-called rod seal, is present, which bears sealingly on the outer circumference of the piston rod.

In the inner circumference of the rod sealing sleeve at least one annular circulating so-called. Guidance band is arranged to rest on the piston rod, which serves the exact axial and safe centric guidance of the piston rod, but not the seal against this piston rod.

In the operation of a power cylinder unit, it could happen that the rod seal fails to load the power cylinder unit. Then a pressure build-up in the necessary pressure chambers to disengage the mechanical security elements, no longer possible.

In this situation, there would be the possibility of relieving and retracting the power cylinder unit, for example by adding an additional further power cylinder unit adjacent thereto, which is precisely defined in applications such as lifting an aircraft because of it, usually only three or four Entry points that would be occupied, is not possible.

The only option is then a subsequent sealing of the rod sealing unit against the under load, mechanically secured in its extended position, piston rod of the working cylinder unit.

This is inventively achieved in that the rod sealing sleeve consists of two successive in the axial direction sleeve parts which are detachably connected to each other, in particular from the freely accessible end face of the arranged at the free end of the cylinder end sleeve portion are screwed together.

If then in the transition region between the two sleeve parts to the inner periphery of the rod sealing sleeve open annular space is present, which is limited in the assembled state of the working cylinder unit of the two sleeve parts on the one hand and the outer periphery of extending therethrough piston rod on the other hand, can also in loaded State of the power cylinder unit can be opened by removing the end sleeve part of this annulus, and therein an emergency seal can be accommodated, which is pressed by re-screwing the end sleeve part and additionally seals the oil pressure chamber outside the defective regular Standsichtung.

Since the load rests on the free end of the piston rod, this emergency seal should not be closed ring-shaped in the initial state.

Preferably, this emergency seal consists of one or more axially successively arranged radially separated, sealing rings which can be wrapped around the piston rod and placed in this annulus one above the other. A less well reproducible solution is to insert a finite sealing strand in the annulus in several turns.

The at least one annular rod seal and in particular the at least one annular guide band is preferably arranged axially apart, ie with respect to the annular space opposite the free end, in particular arranged in the sleeve part facing away from the free end.

The remote from the free end sleeve part is usually releasably secured to the cylinder, in particular screwed.

In order to be able to remove the end sleeve part from the other sleeve part, a, between the two sleeve parts in particular axially acting, Abpress device is present, in particular in the form of axial threaded through holes can be screwed through the end-side sleeve part through the press-off screws from the free end side, which then push away the end sleeve part and thus releases the annular space for inserting the emergency seals.

As long as this emergency has not occurred, in the annulus a circumferential or at one point radially divided spacer ring, in particular in the form of a radially separated additional guide band arranged, which assumes an additional guiding and centering function as the others with a suitable choice of material and dimensions Guide straps too.

After the emergence of the emergency and the expansion of the placeholder ring, in particular the additional guide band, and replacing the same by the emergency seal located in the annulus, in particular the axial, compressible emergency seal.

If the working cylinder unit is designed to be multi-stage telescopic, the described emergency sealing device is provided separately on each telescopic stage.

The axially projecting partially into the cylinder and movable in the axial direction of the piston rod is formed on its outer peripheral surface at least over a considerable part, but at least over the area which is designed by pressure increase in the closed cylinder as the maximum extendable stroke, as a smooth piston sealing surface, with the piston rod fits tightly against the rod seal of the rod sealing unit of the cylinder.

As a result, a first pressure chamber is created which is bounded on the one hand by the cylinder and its cylinder base and the part of the piston rod projecting into the cylinder, and which has a first pressure chamber connection via which this first pressure chamber can be pressurized and by displacing the piston rod through the pressure medium, the piston rod can be further pressed out of the cylinder.

The principle known mechanical position assurance for a certain extended position, ie axial position, the piston rod relative to the cylinder by means of cooperating, preferably positively cooperating, securing elements according to the invention consists of at least one axially rear, the cylinder bottom adjacent area attached to the piston rod piston-side securing element and at the cylinder inner wall in the axial direction several times in succession in each case at least one cylinder-side securing element, which can cooperate with the piston-side securing element by these in positive locking elements, these can preferably be locked together. In this case, this is a securing element as a detent recess in the cylinder inner wall and the other securing element, preferably the piston-side securing element, as at least one movable between a latched and a disengaged position locking projection which fits into the detent recess.

The cylinder-side detent recesses are arranged in the inner peripheral surface of the cylinder, preferably fixed in position.

The locking recesses are preferably always arranged in the axial direction at the same axial distance from each other.

Preferably, the latching projection is movable in the radial direction, preferably pivotable or radially displaceable. The piston-side securing element, in particular the latching projection, protrudes in the engaged, ie latched, position outwards beyond the outer contour of the piston-sealing surface.

If the securing elements, in particular latching projections and latching recesses, are latched into one another, preferably in the radial direction, the axial position of the piston rod is mechanically secured with respect to the piston, even if no pressure is applied in the first pressure chamber.

Preferably, the piston rod is formed at least in two parts by being formed as a smooth piston-sealing surface next to the shaft whose outer peripheral surface over the substantial part of its length, which represents the stroke of its piston rod through the front-side sealed cylinder opening, at the rear free end of this Shank a piston end piece is tightly secured.

The latching projections may then be secured to the outer periphery or the rear free end of this piston end piece of the plunger rod, which simplifies the manufacture of the piston rod.

From the radial rear side of each latching projection, in particular latching segment, a guide projection strives radially inwards and is radially guided in a guide recess which can be present separately from the guide recess which can be acted upon by a second inner pressure chamber.

To be able to act on the part of the radially inwardly directed surface of the latching projection, which is not directly acted upon by the first pressure chamber controlled with a different pressure, namely from a second pressure chamber, is in the interior of the piston rod, in particular the Kolbenendstückes, a Supply space available, with which the at least one guide recess for the guide extension of the movable latching projection is in communication.

The supply chamber communicates with a second pressure chamber connection, which is usually arranged in the outer surface of the cylinder surrounding this piston rod, in connection, usually via a connection space present between and connecting the supply space and the second pressure chamber connection.

In the supply to the second pressure chamber connection or in the second pressure chamber connection, an overpressure valve is usually arranged, which prevents the pressure in the second pressure chamber from rising above a predetermined maximum value, which is generally not higher than the maximum pressure for which the second pressure chamber is designed.

Since changing the axial extension position of the piston rod, the distance between the supply space in the piston or piston end and the second pressure chamber port in the bottom of the surrounding cylinder changes, the connecting space is formed by the hollow interior in the axial direction on hand telescoping, tightly into each other supplied supply pipes of which one is fastened at the rear, free end of the piston rod, in particular the piston end piece to the rear axially abstrebend tightly, and analogously abstrebend from the cylinder bottom for axially front and concentrically aligned another supply pipe. These two supply pipes can be guided directly into each other closely or there may be one or more further intermediate pipes between these two supply pipes, which, however, all together form a dense telescopic pipe system.

The second pressure chamber is thus formed by the connecting space and the supply space and the associated at least one guide recess up to the guide projection guided tightly therein.

Since the working cylinder unit is formed in several stages, preferably the first pressure chambers of all telescopic stages are connected to each other and also the second pressure chambers of all telescopic stages.

In addition, and independent of the previously described adjustable restrictors, a pilot operated check valve is installed in the connection of each pressure chamber to its pressure generator. This unlockable check valve consists of a spring-loaded check valve, which can also be referred to as a "fail-save" -Schließ safety valve, which is unlocked only when an oil control pressure or an electrical control signal against the spring preload and only then specifically a flow in the respective pressure chamber allows.

Preferably, a control is present, which controls the pressure generator, so each pump, and / or each adjustable throttle and each other existing valve, in particular also the each pressure chamber associated unlockable check valve.

For an exact control, at least the pressure difference between the first and the second pressure chamber should be known, preferably also the absolute values of the pressure in the two pressure chambers, for which reason at least one pressure difference sensor is present, which determines the pressure difference and the direction of the radial pressure Pressure-resultant, in particular at the guide projection, between the first and second pressure chamber can measure.

Preferably, however, both in the first and in the second pressure chamber, a pressure sensor is present, which measures the absolute pressure and - as well as a possibly existing differential pressure sensor - signal-technically connected to a preferably existing control and / or the measured value and the direction of the radial pressure Resulting, in particular on the guide projection, on an optical display unit passes.

Preferably, at least in the second pressure chamber, a pressure relief valve is provided to avoid that the pressure in this second pressure chamber above a set pressure increases, since this second pressure chamber, in particular due to its design by means of the described telescopic supply pipes and the hydraulically effective smaller cross-sections, only is loadable with pressure up to its designed strength.

With regard to the method, this object is achieved in that - in multi-stage telescopic design optionally in each affected telescope stage separately - for subsequent sealing of the rod sealing unit against the load under load, mechanically secured in its extended position piston rod solved the end sleeve part of the other sleeve part and is displaced axially so that from the then axially accessible annular space of the placeholder ring, in particular the built-in additional guide band, taken and the circumferentially not closed, usually subsequently cut radially, emergency seal around the piston rod is inserted around in the annulus.

Subsequently, the end sleeve portion is again axially displaced in the direction of the other sleeve part on the rod and screwed to the other sleeve part, whereby the emergency seal is pressurized and sealingly applied to the piston rod.

Since the emergency seal consists of at least one, usually several Notdichtungs elements, usually in cross-section angled, elastically deformable circumferentially not closed, ring whose free ends are usually placed against each other with a radially very flat miter cut, and the unloaded cross section of all in the annulus inserted emergency sealing elements is greater than the cross section of the annular space, the emergency sealing elements are so spread when screwing the end sleeve part to the other sleeve part and pressed between the rod outer surface and the annulus boundary surfaces that a reliable hydraulic seal is made. The same applies to the pressing together of the flat ends of each emergency seal element.

Thus, therefore, the working cylinder unit can be re-sealed in case of failure of the normal rod seal even under load, so with latched locking elements of the mechanical position assurance, and is thus functional again, at least in terms of disengaging the locking elements and the retraction of the piston rod.

The end sleeve part is preferably detached from the other sleeve part by means of a press-on device, since after prolonged operation the two sleeve parts generally adhere firmly to one another despite loosening the screw connections.

When operating a working cylinder device, in particular its working cylinder unit, the method steps such as extension of the piston rod, mechanical securing of the axial position of the piston rod, retraction of the piston rod can furthermore be achieved according to the invention as follows:

The extension of the piston rod is carried out by the first pressure chamber is subjected to a lifting pressure which is greater than the force acting on the piston rod counterforce in the axial direction and the additional internal friction forces of the working cylinder unit.

According to the invention, the second pressure chamber is opened towards the tank, so that working fluid can flow in from the tank when the piston rod is extended in terms of volume, in particular the second pressure chamber can draw in working fluid.

Alternatively, the second pressure chamber to the tank is closed, but is supplied from the first pressure chamber with additional working fluid, however, the connection between the first and second pressure chamber is strongly throttled, so that the pressure present in the second pressure chamber is substantially lower than in the first pressure chamber, and in particular not significantly higher than the hydrodynamic frictional resistance of the oil supply lines in the second pressure chamber. It will typically not be higher than 7 bar, better not higher than 5 bar, better not higher than 3 bar.

It is important that the pressure applied in the second pressure chamber is so low that thereby the detent extensions acted upon are not moved into the latching position.

In addition, according to the invention, an automatic mechanical fixation of the axial height position is provided, if e.g. During the lifting process in case of damage, an uncontrolled drop in the lifting pressure takes place.

For a preferably adjustable check valve is mounted in the intake passage from the tank or in the throttled connection from the first pressure chamber to the second pressure chamber:

Characterized the second pressure chamber is closed by the check valve, and driven by the now in the second pressure chamber relative to the first pressure chamber overpressure which acted upon latching projections in the latching position radially outward on the next locking projections in the cylinder during retraction.

Furthermore, by opening the above-described pressure relief valve in the second pressure chamber damage or even destruction of the second pressure chamber is avoided by exceeding the maximum pressure allowed for this.

For securing the axial position of the partially or fully extended piston rod relative to the cylinder surrounding it - at each stage of the multistage working cylinder unit - first the pressure in the first pressure chamber is lowered by the lifting pressure to a lying below the holding pressure sink pressure, and the piston rod to retracted a small distance, namely so far, until the latching ridge is at the level of the beginning of sinking in the axial direction next detent recess and engages in it.

This locking of the securing elements is effected in that the radial outer side and a part of the radially inner side of the radially movable securing element, in particular of the movable locking projection, is located within the first pressure chamber and is thus acted upon by the sinking pressure prevailing there.

The remaining part of the radial inside of this securing element, in particular latching projection, however, is acted upon by the second pressure chamber with a latching pressure - together with an optionally existing additional latching force that can be provided by a mechanical force transmitter such as a spring - sufficient to to press the locking projection radially outward into the locking recess.

This is achieved according to the invention process safe in that shut off by the aforementioned check valve in the leading to the second pressure chamber supply line at the initiation of the sinking the oil volume in the second pressure chamber and the pressure is increased to the set value of the pressure relief valve, thus significantly above the sink pressure in the first Pressure chamber increases and hydraulically caused by high pressure in the second pressure chamber relative to the first pressure chamber caused radial displacement of the locking projections or securing elements in the locking recesses in the cylinder inner wall.

Once the locking projections are locked in the locking recesses, the pressure in the first pressure chamber can be further lowered to zero, and the piston rod is then held exclusively by the mechanical position assurance. The oil volume in the second pressure chamber remains trapped by the check valve and the pressure relief valve and ensures that after switching off any pressure oil supply and opening of the first pressure chamber and thus a permanent pressure drop to zero, the mechanical locking remains secure.

In the case of damage to the pressure chambers and thus uncontrollable lowering of the working cylinder unit, the locking projections already described drive immediately because of pressure increase in the second pressure chamber - because of the decreasing by the retraction of the piston rod volume in this closed second pressure chamber - compared to the first pressure chamber hydraulically radially to the outside and engage in the next locking recesses, and secure the previously only up to the event of damage hydraulically secured axial position now by positive locking and mechanical. from.

For the retraction of the piston rod from the axially secured by latching axial position, the piston rod is first extended a small distance to lift in the axial direction, the locking projections of the locking recesses and thus cancel the axial frictional radial frictional force caused by, so then the radial inward Driving and thus disengagement of the locking projections can be effected with a smaller force, and after disengagement of the locking projections, the piston rod can be retracted.

For this purpose, first - as described for the extension of the piston rod - proceeded. Subsequently, the controllable check valve is set in the supply line to the second pressure chamber to a higher passage pressure stage, so that by exiting the oil volume from the second pressure chamber, the latching pressure in relation to the first pressure chamber is lowered so far that a resulting, acting in the radial direction inward , Force on the locking projection results.

Then the pressure in the first pressure chamber is lowered by the lifting pressure to a sinking pressure and the piston rod retracted.

This sinking is effected by the applied weight of the previously to be lifted load by expelling the corresponding volumes of oil from the two pressure chambers, wherein the setting of the corresponding throttles provides the desired rate of descent.

embodiments

• 1a: eine zweistufige Arbeitszylinder-Vorrichtung im vollständig eingefahrenen Zustand beider Teleskop-Stufen im Längsschnitt, also geschnitten in axialer Richtung entlang der Linie I - I der 2a,
• 1a1 bis 1a4: das Einsetzen der Notdichtung,
• 1b: die Arbeitszylinder-Vorrichtung gemäß 1a im vollständig ausgefahrenem zustand beider Teleskop-Stufen,
• 1c: eine Detailvergrößerung aus 1b,
• 2a: eine stirnseitige Ansicht der Arbeitszylinder-Vorrichtung gemäß 1a bis c von vorne in Richtung IIa,
• 2b, c: Schnittdarstellungen entlang der Linie II b beziehungsweise II c gemäß 1a, das mittlere Rohr der Arbeitszylinder-Einheit 50 im Längsschnitt und in der stirnseitigen Frontansicht,
• 3a, b: einen Zylinder als Einzelteil im Längsschnitt und in Frontansicht
• 4: ein Kolben-Endstück in perspektivischer Ansicht mit daran angeordneten Rast-Segmenten,
• 5: die Rast-Segmente gemäß 4 in ihrer dortigen Anordnung, jedoch ohne das Kolben-Endstück,
• 6: den Druckverlauf in den beiden Druckräumen der Arbeitszylinder-Einheit gemäß der vorangegangenen Figuren in den verschiedenen Betriebszuständen.

Embodiments according to the invention are described in more detail below by way of example. Show it:

• 1a : A two-stage working cylinder device in the fully retracted state of both telescopic stages in longitudinal section, so cut in the axial direction along the line I - I of the 2a .
• 1a1 to 1a4 : inserting the emergency seal,
• 1b : the power cylinder device according to 1a in the fully extended state of both telescopic stages,
• 1c : a detail enlargement 1b .
• 2a FIG. 2: an end view of the power cylinder device according to FIG 1a to c from the front towards IIa .
• 2b, c : Sectional views along the line II b respectively II c according to 1a , the middle tube of the power cylinder unit 50 in longitudinal section and in the frontal front view,
• 3a, b : a cylinder as a single item in longitudinal section and in front view
• 4 a piston end piece in perspective view with detent segments arranged thereon,
• 5 : the rest segments according to 4 in their local arrangement, but without the piston tail,
• 6 : the pressure curve in the two pressure chambers of the working cylinder unit according to the preceding figures in the various operating conditions.

The 1a respectively 1b show in the retracted or extended state a working cylinder device 100 consisting of a two-stage cylinder unit 50 , usually operated as a hydraulic cylinder unit 50 , and in particular a fastening device 51 for attaching this cylinder unit 50 on a component of the environment.

Like the front view of the 2a and especially the sectional views of the 2b, c show is the power cylinder unit 50 rotationally symmetric about the longitudinal center 10 ' designed so that most of their items, especially the cylinders 21 . 21 ' and the piston rods 22 . 22 ' , Have a circular outer contour and / or inner contour.

The fastening device 51 is in this case at the radially outermost cylinder 21 ' attached and consists of three of this radially, ie in the transverse direction 11 , abstrebenden, in the axial direction 10 extending mounting plates 51 a . b . c in which in the axial direction 10 spaced through holes are present, through which a screw can be made with a component of the environment.

In this outermost cylinder 21 ' the radially outer telescopic stage 50.2 is - as with multi-stage power cylinder units 50 usual - an outer piston 22 ' in the axial direction 10 slidable, at the same time the inner piston 21 for the radially inner telescopic stage 50.1 forms, and in which in turn an inner piston 22 in the axial direction 10 is displaceable.

It is essential to the invention that the pistons 22 . 22 ' opposite to their respective cylinder 21 . 21 ' in both telescope stages 50.1 . 50.2 in each case in a plurality of latching positions along the axial direction can be latched positively as a position assurance 4 , in detail best in the enlargement of 1c shown.

For this purpose, each of the cylinders are in the rear area 22 . 22 ' extend beyond its outer circumference extendable locking elements present in the form of over a portion of the circumference extending latching segments 4a , in the extended state in corresponding locking recesses 4b - Of which in the radially opposite inner peripheral surface 21a of the surrounding cylinder 21 . 21 ' in the axial direction 10 a plurality are formed one behind the other - can lock. The detent recesses 4b are in this case preferably as circumferentially circumferential detent annular grooves 4b educated.

For easier manufacturability are the locking segments 4a each in a piston end piece 6 guided radially, which at the rear end of the otherwise tubular outer piston rod 22 ' is tightly fastened, so that this one at the front end frontally open inner cylinder 21 for the next inner telescope stage 50.1 forms. Likewise, such a piston end piece 6 on the radially inner piston rod 22 attached, which is not hollow in the passage direction in this case, but only from both end faces in the axial direction deep into this piston rod 22 having projecting axial bores.

Also the outer cylinder 21 ' is not made in one piece, but has a tubular central part, which also at its rear end by a tightly attached thereto cylinder tail 6 * is tightly closed.

The pistons 22 . 22 ' are opposite to each of them radially surrounding cylinders 21 . 21 ' each as a plunger, ie piston rod 22 . 22 ' , operated, for which each cylinder 21 . 21 ' near its front, end-side open end in each case in its Innenumfangfäche 21a arranged, annular encircling rod sealing units. The rod sealing units 5 each comprise at least one annular circumferential elastic seal and axially adjacent thereto - usually to a component, the sealing sleeve 29 , summarized - at least one also annularly rotating, the piston rod 22 . 22 ' leading and centering so-called guide band, both on the smooth, as a piston sealing surface 22a acting outer contact surface 22a the respective piston rod 22 . 22 ' in the axial direction 10 slidably abut.

For this purpose is on the respective cylinder 21 . 21 ' each a sealing sleeve 29 at the tubular central part 21d . 21'd tightly attached to the front end, in particular screwed tight, the inner peripheral surface part of the inner peripheral surface 21a or 21'a of the respective cylinder 21 . 21 ' is.

Preferably, in the inner peripheral surface of the sealing sleeve 29 each in the axial direction 10 spaced a plurality of annular grooves arranged in which over the inner peripheral surface radially inwardly above the guide bands 34 and rod seals 33 are arranged.

The formation of the guide sleeve 29 in 1a differs from that of the other figures.

The formation of the guide sleeve 29 according to 1a will be together with the 1a1 to 1a4 explained at the end of the description of the figures.

This will be in the first, radially inner telescopic stage 50.1 a first pressure room 1 formed, which is bounded radially by the inner piston rod 22 and the inner radially surrounding these outer cylinders 21 , this first pressure chamber 1 in the axial direction 10 is limited by the rod sealing unit 5 at the front end of this cylinder 21 as well as the cylinder bottom 21c in the form of the piston end piece 6 , at the rear, closed end of this cylinder 21 is tightly attached, as best in 1b can be seen.

The middle part 21d of the cylinder 21 the radially inner, first telescopic stage 50.1 is in 3a in longitudinal section and in 3b shown separately in the front view from the front:

In an analogous manner, in the radially outer second telescopic stage 50.2 also a first pressure room 1' formed, which in turn is limited in the radial direction by the piston rod 22 ' and the circumferentially surrounding cylinder 21 ' and in the axial direction 10 through the on this cylinder 21 ' arranged rod sealing unit 5 ' at the front, frontally open end of the outer cylinder 21 ' and at the rear end by the close to the middle part 21'd this cylinder 21 ' attached cylinder tail 6 ' ,

Theoretically, the working cylinder unit could 50 also be installed in reverse, and then the outwardly projecting part of the innermost piston rod 22 - Instead of as in the drawn state of the outermost cylinder 21 ' - The fixed and located on a component of the environment component of the working cylinder unit 50 form. Then the fastening device would 51 for securing the power cylinder unit 50 on a component of the environment on the inner innermost piston rod protruding freely from the surrounding cylinder 22 be attached. However, this solution has a number of disadvantages, and will be used at most in exceptional cases.

The piston end pieces 6 . 6 ' as well as the latching projections arranged thereon 4a in the form of rest segments 4a So make no seal between the piston to which they are attached, and the surrounding cylinder, so that the respective first pressure chamber 1 . 1' in the axial direction 10 both in front of and behind the piston end piece 6 extends.

Each of the first two pressure chambers 1 . 1' has a first pressure chamber connection 1a . 1'a , via which it can be supplied with working fluid, usually hydraulic medium, and pressurized.

In the radially outer first pressure chamber 1' the first pressure space port 1'a is a supply bore extending through the cylinder tail 6 ' extending therethrough and on the outside thereof with a pressure source, not shown, is connectable.

The first pressure chamber connection 1a consists for example in an axial through hole 30 extending through the piston end piece 6 ' the radially outer, second telescopic stage 50.2 extends through, and thereby the first two pressure chambers 1 . 1' connects with each other.

It is clear that the necessary mechanical processing on the one hand, the inner peripheral surfaces 21a the cylinder 21 . 21 ' and on the other hand, the outer peripheral surfaces 22a The piston 22 . 22 ' - which are partly identical - is greatly facilitated by the two-sided open end tube shape of the middle parts:

On the one hand, the two-sided frontal accessibility facilitates the incorporation of the axial - except for a two-sided short initial piece - over the entire axial length 10 in the smallest possible distance from each other to be arranged annular grooves as locking recesses 4b with a very accurate cross-sectional contour.

On the other hand, this also facilitates the production of a smooth as possible, serving as a piston sealing surface, the outer peripheral surface 22a on a piston rod 22 . 22 ' ,

At the front in the 3a left end of the inner cross-section is slightly larger compared to the middle part for insertion of a local sealing sleeve 29 and the shoulder in the inner circumferential surface 21a at the right end of this tubular middle part 21d serves for the dense application of a local piston end piece 6 as in the 1a, b shown.

The cross-sectional shape of each of the locking recesses 4b and also the cross-sectional shape of the outer contour of the latching segments latching therein 4a - The one segment of a circular arc corresponding to the arc of the annular detent recesses 4b form - are best in 1c to recognize, together with the perspective views of these locking segments 4a in 5 :

The annular detent recesses 4b are preferably always in the same axial distance 19 arranged to each other.

Here it can be seen that each of the locking grooves 4b has a cross section which is in the axial direction 10 front end a front edge 4b1 that points to the axial direction 10 stands diagonally and to the longitudinal center 10 ' in the direction of extension 10 this approximates.

The tail flank 4b2 every latching groove 4b on the other hand, consists of a perpendicular to the axial direction 10 standing surface, in particular ring surface.

The outer end of the tail flank 4b2 and the rear end of the front edge 4b1 are over a particular parallel to the axial direction 10 running middle flank connected.

The outer contour of each of the locking segments 4a is designed analogously with a front edge 4a1 , a middle part and a tail flank 4a2 in terms of the inclination of the front edge 4a1 with the slope of the front edge 4b1 the locking ring groove 4b preferably matches.

The dimensions are also chosen so that the locking segment 4a in one of the annular detent recesses 4b can engage.

All mentioned flanks are of course due to the rotationally symmetrical design in the axial direction 10 considered annular or circular segment (on sides of the locking segments 4a) designed, in particular the 5 lets recognize.

In the present case, each piston end piece carries 6 . 6 ' in an incorporated in its outer circumference receiving annular groove 7 evenly distributed over the circumference of six such locking segments 4a , with respect to axial extent and radial extent exactly in the receiving annular groove 7 fit, so are axially guided by this and can be immersed in this preferably so far that they do not over the outer circumference of the piston end piece 6 . 6 ' protrude radially.

As the 5 as well as the 1a, b show, protrudes from the radially inner rear side of each of the locking segments 4a a fixedly connected, cylindrical guide extension 4a3 to the rear, ie radially inward from, in a corresponding cylindrical guide recess 13 of the piston end piece 6 . 6 ' is guided tightly in the radial direction.

The radially extending guide recesses 13 penetrate the annular or sleeve-shaped piston end pieces 6 . 6 ' from the inside to the outside and thus stand above its central interior 6c in connection with each other, which due to the sleeve shape, the piston end piece 6 . 6 ' from the rear end 6a to the front end 6b penetrates.

Also on the radially inwardly facing back of each of the locking segments 4a is on both sides next to the guide extension 4a3 one compression spring each 8th arranged, which acts in the radial direction and with its inner free end at the bottom of the receiving annular groove 7 supports, so the ring segments 4a apply radially outward.

Without further force so would in a piston tail 6 . 6 ' whose resting segments 4a at the axial position of an outer circumferential locking groove 4b due to the force of these springs 8th the resting segments 4a in the surrounding annular detent recess 4b engage, as for example in the cross-sectional view of 2 B . 2c to recognize this latched state once for the radially inner, first telescopic stage 50.1 ( 2 B) and once for the radially outer second telescopic stage 50.2 ( 2c ) demonstrate.

In practice, the locking segments 4a but not only by the force of the springs 8th but especially by means of a pressurization of the interior 6c of the piston end piece 6 which thereby also on the rear radially inner free end face of each of the guide extensions 4a3 acts, pressed radially outwards when the interior 6c acting as supply room 14 for the leadership recesses 13 serves, the butt-end 6 . 6 ' is pressurized.

This can be done by keeping the interiors 6c the piston end pieces 6 - how best in 1b to recognize - each part of a second, radially inner pressure chamber 2 . 2 ' are, which are also related to each other.

Here are the interiors 6c the two piston end pieces 6 characterized pressure-tightly connected to each other, that extending between the two in the axial direction a telescopic tube arrangement is present, with a supply outer tube 31 and a supply inner tube which can be displaced tightly therein 32 of which the first is close to a piston end piece 6 is attached and in its interior 6c and thus supply room 14 opens, and the other analog in the other piston tail 6 ' is attached, and in its interior 6c and supply room 14 ends.

Between the rear end 6a the axially rear piston end piece 6 6 ' and an axial through bore of the cylinder end piece 6 * is also a telescopic tube assembly consisting of supply outer tube 31 ' and more tightly guided supply inner tube 32 ' present, the latter one with connection opening in the outside of the cylinder end piece 6 ' communicating with that second pressure chamber 2 forms the second pressure chamber port 2'a.

This second pressure chamber connection 2'a and the two telescopic tube arrangements 31 . 32 . 31 ' . 32 ' are preferably central, that is concentric with the longitudinal center 10 ' arranged.

That in the axial direction 10 front piston tail 6 could be at the front end 6b also be closed and this butt-end 6 then have no sleeve shape but a cup shape, however, the sleeve shape is selected for manufacturing reasons, and this piston end piece 6 in the shoulder of a in the rear end face of the axially inner piston 22 introduced blind hole bore tightly inserted, in particular screwed.

In the 1a visible blind hole from the front end face of this inner piston 22 on the other hand serves only as an attachment for a not shown in the figures, on the front end of this piston rod 22 Applicable adapter part for adaptation to different interfaces of the loads to be picked up.

Thus, the front in the axial direction, second pressure chamber 2 Essentially, from the interior 6c of the front piston end piece 6 and the blind hole in the rear end of the piston rod 22 consists of one on the rear second pressure chamber connection 2a connecting room 15 formed by the interior of the first telescopic tube assembly 31 + 32, with the rear second pressure space 2 ' connected, essentially in the interior 6c the rear piston end piece 6 ' exists, and this in turn is over another connection space 15 ' formed by the interior of the second telescopic tube assembly 31 '+ 32', with the second pressure chamber port 2 ' connected.

The second pressure chamber connection 2a the front first pressure chamber 2 is through the mouth of the connecting space 15 in the front piston end piece 2 educated.

Thus, the contiguous radially inner, second pressure chamber 2 . 2 ' via the second pressure chamber connection 2 ' in the outside of the piston end piece 6 ' be pressurized, and the contiguous first pressure chambers 1 . 1' by the one or more in the outer peripheral surfaces of the cylinder end pieces 6 ' shown first pressure chamber connections 1'a ,

This can be used to drive the piston-cylinder unit 50 extend hydraulically and retract by the load and thereby the piston rods 22 . 22 ' at one of the desired annular locking recesses 4b of the respectively adjacent radially surrounding cylinder 21 . 21 ' latching positively, the thereby prevailing in the individual working conditions pressure conditions in 6 are shown:

In 6 is - for the individual pressure chambers 1 . 1' on the one hand and 2 . 2 ' on the other hand - the pressure curve from the beginning of the insert on the lifting and securing a on the working cylinder device 100 and thus the working cylinder unit 50 resting load until decommissioning the power cylinder device 100 shown.

In this case, the standstill pressure p0 is that pressure which in the first pressure chamber 1 . 1' must prevail, to - without mechanical position assurance - one on the working cylinder unit 50 seated load L Keep yourself at rest, so do not raise or lower further.

First, the load bearing surface, usually the upper end of the vertically arranged working cylinder unit 50 , spaced below the load to be lifted L ,

Approaching the load pick-up point:

Therefore, the first pressure chamber 1 . 1' initially with a very low probing pressure p3, which is just sufficient to compensate for the weight of the telescopic stages and the internal friction and extend the first rod slowly without load, for example, 3 bar, applied, and thus raised without load until the concern of the load bearing surface of the working cylinder -Unit 50 at the load.

The pressure in the second pressure chamber 2 . 2 ' is kept lower, and so low that the latching projections, in particular latching segments 4a , with respect to the receiving annular groove 17 in the radially inwardly driven, deactivated position, in the presence of the springs 8th also taking into account their spring force.

The described start of the load pick-up point is at several cylinder units 50 successively with all - typically three - working cylinder units 50, which are to be used for the horizontal synchronous lifting of the load carried out.

Extend (lift load):

After all - typically three - cylinder units 50 to be used for horizontal synchronous lifting of the load, the load L have contacted at their respective load pick-up point, the load lifting can begin.

The following process descriptions will each typically be on one of the slave cylinder units involved in the synchronous vertical movement of the load to be held horizontally, typically three 50 described.

It goes without saying that the following is for the one cylinder unit 50 described process steps respectively parallel and synchronous also on all other working cylinder units involved in the horizontal vertical movement of the load 50 must be performed.

The pressure in the first pressure chamber 1 . 1' is increased to a lifting pressure p1 , which is higher than the standstill pressure p0, and maintain this lifting pressure p1 until the load is raised to the desired height. The fine adjustment of the lifting pressure p1 determines the lifting speed.

The pressure in the second pressure chamber 2 . 2 ' In any case, it remains lower than the lifting pressure p1 , in particular lower than the standstill pressure p0 and in particular also lower than the probing pressure p3 , preferably at the same base pressure p4 , which already when starting the load in the second pressure chamber 2 . 2 ' had prevailed.

Either the lifting of the load takes place on an axial lifting position, which, in particular about 20 mm, is above the desired desired lifting height, and / or by a difference which is less than the distance 9 in the axial direction 10 mutually adjacent locking recesses 4b ,

Alternatively, all, in the present case two, telescopic stages until reaching their inner mechanical end stops, namely the inner lower annular edges of the sealing sleeves 29 , ie to the maximum extension position, extended.

If a target lifting height to be approached, which should not be positively secured by mechanical locking, and thus made use of the function of the pilot-operated check valves, the target lifting height can be approached exactly before switching off, and the method described below Locking, securing and unlatching (before lowering to the set lifting height) can be dispensed with.

This procedural simplification is due to the invention mainly due to the fact that in case of unintentional pressure drop in the first pressure chamber, which is crucial for lifting and holding the load by increasing the pressure in the second pressure chamber - due to the volume reduction - the positive locking by hydraulic extension of the locking projections in the next achieved locking recesses in the second pressure chamber is automatically triggered. The second pressure chamber is completely enclosed by the first pressure chamber. Damage to the second pressure chamber by external influences is therefore excluded.

snap:

Because at the nominal lifting height all telescopic stages 50.1 . 50.2 the power cylinder unit 50 be positively locked, is from this state of at least one piston rod 22 . 22` slightly retracted by the pressure in the working space 1 . 1' is lowered until slightly below the standstill pressure p0 while at the same time the pressure in the second pressure chamber 2 . 2 ' is increased to such latching pressure p5 , which is a radial extension of the locking segments 4a causes, and for this purpose, preferably well above the instantaneous pressure in the first pressure chamber 1 . 1' lies.

As a result, the at least one piston rod 22 . 22` slightly retracted to the radially outwardly acted locking segments 4a these piston rods 22 . 22` in the next in the retraction following locking recess 4b engage.

Secured:

As soon as this is achieved-which is preferably automatically verifiable by means of corresponding sensors-the pressure in the working space can now be achieved in the now positively secured state 1 . 1' be lowered, preferably to zero.

It is only important that the pressure in the second pressure chamber 2 is kept so high - and this is well below the Einrastdruck p5 can lie - that the locking elements 4a continue to be acted upon radially outward, even taking into account the possibly existing springs 8th and / or the friction losses and stiction between the securing segments 4a and the piston end piece 6 ,

Therefore, the pressure in the pressure chamber is preferably in the secured state 2 . 2 ' above the pressure in the first pressure chamber 1 . 1' , The supply spaces of the two pressure chambers 2 . 2 ' and 1 . 1' are then preferably by the inventively provided unlockable check valves closed. The pressure generation can then be turned off.

Freak out:

If the state of the support of the load at the desired lifting height to be terminated due to positive locking, so must first - so before such a retraction of the at least one piston rod 22 . 22 ' that the piston cylinder unit 50 out of engagement with the load device - first the locking segments 4a from the detent recesses 4b be disengaged.

After switching on the pressure generation, the pilot-operated check valves open automatically and allow the pressure oil supply to the first and second pressure chambers.

To the contact pressure in the axial direction between the rear edge 4a2 and the corresponding rear edge 4b2 the detent recess 4b cancel, the at least one piston rod 22 . 22` initially slightly further extended.

This is the pressure in the first pressure chamber 1 . 1' to a lifting pressure above the standstill pressure p0 raised, the further must be so high that on the rest segment 4a from radially outside, ie from the first pressure chamber 1 . 1' from acting forces are greater than all of the radially inward, so from 2 , inner pressure chamber 2 . 2 ' from acting forces, which is beyond the pressure in the second pressure chamber 2 . 2 ' also the power of the springs 8th could be.

Preferably, in this case, the pressure in the second pressure chamber 2 . 2 ' on the compared to the standstill pressure p0 much lower security pressure p4 set.

Retracting (sinking):

Once the hedging segments 4a are retracted into the radially retracted, deactivated position is for the intended retraction of the piston rods 22 . 22 ' the pressure in the first pressure chamber 1 . 1' now on a sink pressure p2 below the standstill pressure p0 lowered, the value of the sink pressure p2 is chosen depending on the desired descent rate.

In this state, it merely has to be ensured that a resultant force acts radially inwards on the latching segments 4a is exercised, even taking into account the then radially inwardly and radially outwardly acting pressures in the first pressure chamber 1 . 1' and second pressure chamber 2 . 2 ' ,

As a rule, this is the pressure in the second pressure chamber 2 . 2 ' clearly under pressure in the first pressure chamber 1 . 1' held and preferably the pressure in the second pressure chamber 2 . 2 ' at the level of the security pressure p4 maintained during the sinking pressure p2 in the first pressure room 1 '1' is much higher.

After the piston rods 22 . 22` have reached the fully retracted position, so their piston end pieces 6 . 6 ' on the bottom of the surrounding cylinder 21 . 21 ' can sit up, the pressure in both pressure chambers 1 . 1' and 2 . 2 ' be lowered to zero and thus also the at least one, the working cylinder unit 50 supplying pressure generator 16 . 17 be switched off.

Formation of the guide sleeve 29:

1a shows a 2-part design of the guide sleeve 29 , namely with a main part in the form of the sleeve part 29a and one from the free end in the axial direction 10 placed on it, end sleeve part 29b ,

These two sleeve parts 29a . b limit one to the inner circumference of the guide sleeve 29 open annulus 40 in the region of the transition between the two sleeve parts 29a . b in the assembled state of the power cylinder unit 50 from the outer circumference of the through the guide sleeve 29 extending therethrough 22 is closed.

As with such a guide sleeve 29 such a cylinder unit 50 usual, are initially once inside circumferential grooves in the guide sleeve 29 , here in the sleeve part 29a , provided in which axially offset in each case at least one rod seal 33 located.

Axially offset on both sides in each case at least one so-called leader tape 34 arranged in a likewise respectively in cross section correspondingly shaped inner circumferential groove, wherein the cross section of the guide belt 34 that of a flat rectangle is with its main extension direction in the axial direction 10 , and which is little or not elastic and the exact centric guidance of the piston rod 22 in the guide sleeve 29 Serves what the compressible, elastic rod seals 33 alone can not provide. This ensures that there is never any metallic contact between the chrome plated surface of the piston rod and the guide sleeves 29a . b can occur.

The annulus 40 is thus with respect to the rod seals 33 on the from the pressure room, which the rod seals 33 limit, formed opposite side.

The cross section of the sleeve part 29b is designed so that he has the annulus 40 limited on the radial outside as well as on a front side.

From the annulus 40 to the free end of this end sleeve part 29b axially offset another inner circumferential groove is formed in which a scraper 38 sitting, which is also on the outer circumference of the piston rod 22 is applied and the penetration of dirt between the piston rod 22 and guide sleeve 29 should prevent.

In the event that both rod seals 33 fail and in the axial direction under load and mechanically locked piston rod 22 can no longer be unlocked and retracted, the annulus is used 40 to this, if necessary, an emergency seal 37 to bring in, as in the 1a1 to 1a4 , Detailed views 1a , shown:

In normal operation, so with intact rod seals 33 , is located according to 1a1 at least one placeholder ring 36 , For example, plastic such as silicone, which should only prevent deposition of dirt in the annular space, as in 1a1 and 1a2 shown above. However, preference is given in the annulus 40 a radially cut, additional guide band 34 arranged, with an appropriate material selection and dimensioning in normal operation assumes an additional leadership function. Because these guide bands 34 usually have a small radial thickness, can radially outward around the guide band 34 around a suitably sized support ring 41 in the annulus 40 be inserted to guide bands 34 to use with usual, small thickness.

That in the annulus 40 introduced additional guide band 34 can that in the figures 1a1 and 1a2 Guide band shown next to it 34 between the rod seals 33 and the annulus 40 , replace or as an additional guide band 34 to be available.

In case of failure of both rod seals 33 - This will virtually never occur in practice because of the internal, comprehensively protected arrangement without external effects - this annulus 40 opened by the screw connection 39 - as in 1a1 shown in the lower half - between the two sleeve parts 29a . b from the free end of the end sleeve part 29b ago performed, solved, and for pressing the sleeve part 29b from the sleeve part 29a into the through-tapped holes 35 of the end sleeve part 29b - as in 1a1 shown in the upper half - screws screwed in until this on the end face of the sleeve part 29a abut and further screw the end sleeve part 29b pull the trigger.

If the two sleeve parts 29a . b sufficiently far by axial displacement of the sleeve part 29b on the piston rod in the axial direction 10 are removed from each other, according to 1a2 the placeholder ring 36 , In particular, the radially slotted, additional guide band from the annulus 40 pushed out, bent and so between the two sleeve parts 29 a . b taken out.

Now, according to 1a3 the emergency seal 37 in the annulus 40 in this case, in the end sleeve portion 29b is designed to be inserted.

As in 1a3 pictured above, the emergency seal 37 preferably of a plurality of angular cross-section, elastically deformable, annular, but not circumferentially closed, sealing elements 37a . b exist whose respective ends are placed against each other with a very flat miter cut.

The one seal elements 37a have a V-shaped or roof-shaped cross section, which is designed so that they can be stacked in the axial direction. In the axial direction is at the end of the stack in each case a differently shaped cross-section sealing element 37b . c arranged, which in the axial direction 10 has an outer surface which is the peripheral edge of the annular space 40 fits and usually perpendicular to the axial direction 10 stands and thus as an adapter between the cross-sectional shape of the first, middle sealing elements 37a and the cross-sectional shape of the annulus 40 serves.

As in 1a3 shown below, the emergency seal 37 - Be in a less preferred embodiment, an elastic, finite thin strand of sealing material whose diameter is smaller than the radial width of the annular space 40 in the circumferential direction in several turns around the outer circumference of the piston rod 22 will be placed around in the annulus.

Because the unloaded cross-section of the emergency seal 37 , especially all in the annulus 40 inserted emergency sealing elements 37a . b . c is greater than the cross section of the annulus 40 , These are the subsequent axial approach and screwing the end sleeve part 29b to the sleeve part 29a according to 1a4 so spread and between the outer surface of the rod and the inside of the annulus presses that a reliable hydraulic seal is made. The same applies to the pressing together of the flat ends of each of the sealing elements 37a . b . c ,

This training of the sealing unit 5 and its seal sleeve 29 is in 1a by way of example only on the radially inner cylinder 21 ' opposite the piston rod running in it 22 shown, but in a multi-stage cylinder unit 50 this would be between cylinders 21 and piston rod 22` the other telescopic stages in this form available.

LIST OF REFERENCE NUMBERS

1,1 '

first pressure chamber

1a, 1'a

first pressure chamber connection

2, 2 '

second pressure chamber

2a, 2'a

second pressure chamber connection

3.3 *

face

4

Position assurance

4a

Locking element, locking projection, locking segment

4a3

Leadership extension

4a1,4b1

Front-edge

4a2,4b2

Rear-edge

4b

Securing element, snap-in recess

5.5 '

Rod sealing unit

6.6 '

Piston Tail

6 *

Cylinder Tail

6a

rear end

6b

front end

6c

inner space

7

Pick-up groove, receiving ring groove

8th

compression spring

9

axial distance

10

axial direction, axial direction

10a

Deploying direction

10 '

longitudinal center

11

Radial direction, transverse direction

12

Circumferential direction

13

Guide recess

14

Supply room

15

Marriage Room

16

pressure generator

17

pressure generator

18

Distance Sensor

19

distance

20

control

21, 21 '

cylinder

21a

Inner peripheral surface

21b

Cylinder interior

21c

Cylinder floor

21d

midsection

22, 22 '

piston rod

22a

Peripheral surface, outer circumference, piston sealing surface

23

throttle

24

throttle

25

pressure sensor

26

pressure sensor

27

tank

28

Over-pressure valve

29

grommet

30

Through Hole

31

Supply outer tube

32

Supply inner tube

33

rod seal

34

guide band

35

threaded hole

36

Placeholder ring

37

Emergency seal

37a, b, c

Sealing element

38

scraper

39

screw

40

annulus

41

support ring

50

Working cylinder unit, hydraulic cylinder unit

50.1,50.2

telescopic stage

51

fastening device

51 a, b

plate

52

Through Hole

100

Working cylinder device

L, L '

extension length

Claims (18)

Working cylinder device (100) with at least one multi-stage telescopic working cylinder unit (50), in particular hydraulic cylinder unit (50), with per telescopic stage (50.1, 50.2) - a cylinder (21, 21 ') with a cylinder bottom (21c ) at the rear end and in the particular circular opening at the front, open end of the cylinder interior (21 a) attached, annular rod sealing unit (5), - one close by the rod sealing unit (5) and its annular rod seal (33) axially displaceable piston rod (22, 22 ') which protrudes axially outward from the cylinder (21, 21') over part of its length and whose outer peripheral surface (22a) is formed as a smooth piston sealing surface (22a) and abuts on the rod sealing unit (5), thereby inside the cylinder (21, 21 ') between the rod sealing unit (5), the piston rod (22, 22') and the cylinder (21, 21 ') trained first tightly closedb aren pressure chamber (1, 1 '), which has a first pressure chamber connection (1a, 1'a), - a mechanical position assurance (4) for the axial position of the piston rod (22, 22') relative to the cylinder (21, 21 ') by means of cooperating securing elements (4a, b), wherein the rod sealing unit (5) comprises a rod sealing sleeve (29), which in its inner circumference the at least one annular rod seal (33) and in particular at least one annularly circulating guide band (29). 34) for engagement with the piston rod (22), characterized in that - the rod sealing sleeve (29) comprises two axially successive sleeve parts (29a, b), - releasably connected to each other, in particular from the freely accessible end face of the at the free end of the cylinder (21) arranged sleeve part (29b) are bolted together, - in the transition region between the two sleeve parts (29a, b) to the inner circumference of the rod sealing sleeve (29) towards open annular space (40) is present, in particular of the two sleeve parts (29 a, b) on the one hand and the outer circumference of the extending therethrough piston rod (22) on the other hand limited. Working cylinder device (100) after Claim 1 , characterized in that - the at least one annular rod seal (33) and in particular the at least one annular guide band (34) away from the end adjacent the free end, sleeve part (29b), in particular in the facing away from the free end sleeve part (29a ) are arranged and / or - the remote from the free end sleeve part (29 a) on the cylinder (21) releasably secured, in particular screwed, is. Working cylinder device (100) according to one of the preceding claims, characterized in that - a, in particular axially acting, pressing device between the two sleeve parts (29a, b) is arranged, - in particular in the form of axial threaded through-holes (35) through the end-side sleeve part (29b) through the press-off screws (39) from the free end side are screwed. Working cylinder device (100) according to one of the preceding claims, characterized in that in the annular space (40) - either a placeholder ring (36), in particular in the form of an additional guide strip (43) - or an axially compressible emergency seal ( 37) is arranged, - in particular in each case radially cut-through shape. Working cylinder device (100) according to one of the preceding claims, characterized in that - at least one piston-side securing element (4a) in the rear region of the piston rod (22, 22 ') is arranged and - at least one cylinder-side securing element (4b) in the axial direction ( 10) is arranged a plurality of successively on or in the inner circumferential surface (21a) of the cylinder (21, 21 ') axially away from the rod sealing unit (5). (positive position assurance) Working cylinder device (100) according to any one of the preceding claims, characterized in that - the at least one mechanical position assurance (4) is a positive position assurance (4), by the interaction of the securing elements (4a, b) and the detent recesses ( 4b) comes about by the locking projections (4a) in the locking recesses, in particular fit, retract, - in particular the detent projections (4a) on the outer circumference of the piston rod (22) and the detent recesses (4b) on the inner circumference of Cylinders (21) are arranged. Working cylinder device (100) according to one of the preceding claims, characterized in that - the at least one piston-side securing element, in the form of the at least one latching projection (4a), protrudes outward over the outer contour of the piston-sealing surface (22a) in the radial direction (11) at least in its latched position and / or - the at least one piston-side securing element , in the form of at least one latching projection (4a), in the radial direction (11) relative to the piston rod (22) between a latched and a disengaged position movable, in particular displaceable or pivotable, is. Working cylinder device (100) according to one of the preceding claims, characterized in that - the at least one piston-side detent projection (4a), in the first pressure chamber (1, 1 ') is arranged and in particular in the first pressure chamber (1, 1' ) located radially outer surface of the latching projection (4a) is greater than the in the first pressure chamber (1, 1 ') located radially inner surface of the latching projection (4a), - in particular by the radial inner surface of each piston-side latching projection (4a) a guide projection (4a3) strives radially inward and guided in a guide recess (13) tight in the radial direction, so that the freely accessible radially inner end face of the guide projection (4a3) not directly with the first pressure chamber (1 , 1 ') is in communication and / or - the at least one cylinder-side detent recess (4b), on or in the inner peripheral surface (21a) of the cylinder (21, 21') is arranged fixed in position. (Second, inner pressure chamber, red) Working cylinder device (100) according to one of the preceding claims, characterized in that - in the interior of the piston rod (22, 22 '), in particular of the piston end piece (6), a supply space (14) is present and - at least one, in particular all, guide recess (13) with the supply space (14) is connected and form a second pressure chamber (2, 2 '), - the second pressure chamber (2, 2') with a second pressure chamber connection ( 2a, 2'a) in the outer surface of the surrounding cylinder (21, 21 ') via a connecting space (15) is connected. (Control elements) Working cylinder device (100) according to one of the preceding claims, characterized in that - both the first pressure chambers (1, 1 ') and the second pressure chambers (2, 2'), in particular each pressure chamber (1, 1 ', 2, 2 ') with one, preferably each one, pressure generator (16, 17) are in communication, in particular via a, in particular adjustable, throttle (23, 24), and preferably one, in particular with respect to the closing pressure adjustable and / or unlockable, check valve, and - there is a controller (20) controlling each of the pressure generators (16, 17) and / or each adjustable restrictor (23, 24) and each adjustable and / or releasable check valve. A power cylinder apparatus (100) according to any one of the preceding claims having a plurality of power cylinder units (50), characterized in that - a controller (20) comprises all the power cylinder units (50) and / or all pressure generators (16, 17) and / or all adjustable valves, in particular all adjustable throttles (23, 24), all adjustable and / or unlockable check valves and all adjustable overpressure valves (28) controls, and - either all first pressure chambers (1,1 ') of all working cylinder units (50 ) with a first distributor chamber (51), which communicates with a first pressure generator (16) and all second pressure chambers (2, 2 ') of all working cylinder units (50) with a second distributor chamber (52), with a second Pressure generator (17) is connected, are connected interruptibly, or - all pressure chambers (1,1 ', 2, 2') of all working cylinder units (50) with a first distribution chamber (51) with a pressure generator (16) in combination stands, are connected interruptible. A method for operating a power cylinder device (100) comprising a multi-part sealing sleeve (29) with a radially inwardly open annular space (40) at the boundary between the sleeve parts (29a, b), in particular according to one of the preceding claims, characterized in that, for the subsequent sealing of the rod sealing unit (5) with respect to the piston rod (22) secured under load, mechanically secured in its extended position - the end sleeve part (29b) is released from the other sleeve part (29a) and axially pushed away the annular space (40) an emergency seal (37) is inserted, - the end-side sleeve part (29b) to the other sleeve part (29a) is axially approximated and braced in contrast. Method according to Claim 12 , characterized in that the end-side sleeve part (29b) is detached from the other sleeve part (29a) by activating a press-off device. Method according to Claim 12 or 13 , characterized in that prior to insertion of the emergency seal (37) and after the axial spacing of the end-side sleeve part (29b) a slotted guide band (36) axially pushed out of the annular space (40) and removed from the piston rod (22), especially by bending. Method according to one of the preceding method claims, characterized in that the mechanical securing of the axial position of the extended piston rod (22, 22 ') is achieved by - in the first pressure chamber (1, 1') the pressure of the lifting pressure (p1 ) is reduced to a sinking pressure (p2) which acts on the piston rod (22, 22 ') with a force which is less than the sum of a counter-force acting on the piston (22, 22') and the internal friction Forces of the working cylinder unit (50) until the piston (22, 22 ') is axially retracted so far that the positively cooperating securing elements (4a, b) engage each other, so engage, in particular the at least one locking Projection (4a) can engage in one of the latching recesses (4b) and - the interlocking is effected. Method according to one of the preceding method claims, characterized in that for securing the engagement of the securing element (4a), in particular of the latching projection (4a), in particular of the latching segment (4a) is effected by the latching - Both the radial outer side and a part of the radially inner side of this radially movable securing element (4a), in particular the first pressure chamber (1, 1 '), with the sink pressure (p2) is applied, and - the remaining part of Radial inside of the securing element (4a) is particularly the second pressure chamber (2, 2 '), with a latching pressure (p3) and optionally an additional, in particular mechanically effected, latching force (F3) is acted upon, wherein - latching Pressure (p3) and the optionally existing latching force (F3) in relation to the sinking pressure (p2) are chosen so that there is a, on the securing element (4a) radially acting resultant force directed radially outward is, esp On the other hand, if the detent force (F3) is present, the detent pressure (p3) is selected to be higher than the descent pressure (p2). Method according to one of the preceding method claims, characterized in that for extending the piston rod (22, 22 ') out of the cylinder (21, 21') - the first pressure chamber (1, 1 ') has a lifting pressure ( p1) which acts on the piston (22, 22 ') with an extension force which is greater than the sum of a counter-force acting on the piston (22, 22') and the internal friction forces of the working cylinder Unit (50) until a predetermined target extension length is reached, and in particular A1: either the second pressure chamber (2, 2 ') to the tank (27) is open, so that fluid from the tank in the enlarging during extension second pressure chamber (2, 2 ') can flow in, in particular can be sucked, A2: or the second pressure chamber (2, 2') to the tank (27) is closed, but with the first pressure chamber (1, 1 ') during the Ausfahren, in particular severely throttled, is connected. Method according to one of the preceding method claims, characterized in that for controlled retraction the piston rod (22, 22 ') acted upon by a counter-force directed in the retraction direction into the cylinder (21, 21') - first according to one of the steps A1 or A2 is proceeded, - then the detent pressure (p3) and the optional detent force (F3) in relation to the prevailing in the first pressure chamber (1, 1`) lifting pressure (p1) are selected so that results in a force acting on the securing element (4a) resulting force, which is directed radially inward, in particular by a throttle (23) in the pressure chamber port (1a) to the first pressure chamber (1, 1 ') is set accordingly, wherein this is maintained until the piston rod (22, 22 ') has reached the predetermined extension length (L), in particular the fully retracted extension length (L).

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