EP1538343A2 - Locking cylinder - Google Patents

Abstract

The locking cylinder (20) has two load-holding descent brake devices (150.1, 150.2) in fluid connection with two working chambers (45, 33), so that when the first side (46) of the piston (22) is put under pressure, the piston is displaced in one direction. When it is subject to a counter-pressure lower than the working pressure, this acts on the other side (44) of the piston, displacing it in the opposite direction.

Description

The invention relates to a locking cylinder with a cylinder and a piston using a fluid Pressure medium movable parallel to the longitudinal axis of the cylinder is, and which is provided with a piston thread, the with the formation of a non-self-locking thread with a spindle thread of a spindle is engaged, the around a parallel to the longitudinal axis of the cylinder arranged Rotary axis is rotatable and the at least one outward has open locking recess, in the at least an acted upon by spring force of a spring Locking body can engage, against rotation secured around the axis of rotation of the spindle and relative to the Cylinder is mounted movably and by means of the Spring force of the spring in a locking position is convertible, in which he is in the locking recess the spindle engages, so that then a rotation of the Spindle is blocked around its axis of rotation, and where the Locking body using a fluid working medium against the spring force of the spring from the locking position in an unlocking position can be converted, in the spindle is rotatable about its axis of rotation about a To allow movement of the piston along the cylinder.

Such a locking cylinder is known from JP 083 034 10 A became known. There is a locking body large-volume locking piston provided by the central Through hole, a shaft of a ball screw extends and with a variety of concentric to Spindle arranged and towering along the spindle Teeth is integrally connected. In the locked position the teeth of the locking piston engage with opposite teeth of a gear rotatably with this concentrically receiving spindle is connected. As a result, a kind of toothed coupling is formed. Of the Locking piston points at his pointing away from the teeth Side a hollow section with an internal toothing, and the tooth flanks of the teeth of the internal teeth extend parallel to the axis of rotation of the spindle. The Internal gearing is engaged with a matching External toothing of a pinion, fixed with a End cover of the cylinder is connected. To this Way, the locking piston is parallel to the axis of rotation of Ball screw displaceable, but against rotation around stored the spindle axis blocked.

On the outer circumference of the locking piston is a circumferential Seal provided, which can be acted upon by a pressure medium Pressure medium space towards the end cap of the cylinder seals.

This construction of a locking unit is expensive and takes up comparatively much space. For unlocking or locking the design and large be compact and therefore weighty locking piston comparatively large forces needed and / or it must comparatively long locking or locking times in purchase be taken, which is also a corresponding Security risk means. The locking piston must be at his Outer circumference sealed with a circumferential seal what happens when moving the locking piston for the purpose the locking or unlocking to corresponding frictional forces leads, reducing the efficiency of this locking cylinder is limited.

The ball screw is so on the cylinder over a Ball bearing and one at the free end of the spindle shaft mounted plain bearing clamped clamped that a Movement of the spindle in the longitudinal direction of the cylinder is not is possible while rotating the spindle around its Longitudinal axis is possible. This is supported by the free end of the spindle shaft sliding on an inner surface of the End cap of the cylinder and the ball bearing is by means of an external thread of the ball screw screwed nut against a transverse to the cylinder running paragraph fixed.

This construction is limited to applications in which only comparatively small loads can be raised. For larger loads, however, it can cause wear come to the feeding of the plain bearing. It can to Formation and detachment of metal shavings or particles come, which the function of the locking unit to a blockade of the Locking piston. This means an unacceptable security risk.

The control of the locking piston having locking unit and controlling the movement of the piston take place in this construction via mechanically coupled Directional valves such that when lifting or in the Lowering the load to an undesirable lead of the Pistons can come. This means a difficult to control Piston movement. Especially at elevated pressures or Piston velocities may cause cavitation at the Piston seal and the piston rod come, what a Security risk means and what life span limited accordingly.

It is therefore an object of the invention to provide a locking cylinder to create, in particular, a higher Operational safety allows.

This object is according to a first solution thought or according to a particularly preferred embodiment of the The aforementioned locking cylinder by the following Characteristics solved:

The lock cylinder comprises a cylinder and a Piston, using one of two sides of the piston deliverable fluid pressure medium parallel to the longitudinal axis the cylinder is movable and the one with a piston thread that is under training one not self inhibiting thread with a spindle thread of a spindle is engaged, which is parallel to the longitudinal axis of the Cylinder arranged axis of rotation is rotatable and the at least one outwardly open locking recess in which at least one by means of a spring force Spring can engage engaged locking body, the against rotation about the axis of rotation of the spindle secured and axially parallel to the axis of rotation of the spindle slidably mounted on a head of the cylinder, and the spring force of the spring in a locking position is convertible, in which he in the Locking recess of the spindle to form a positive and bidirectional locking of the Spindle engages, so that then rotation of the spindle to its axis of rotation in opposite directions of rotation is blocked and wherein the locking body using a fluid working fluid against the spring force of Spring from the locking position into an unlocked position is convertible, in which the spindle to their Rotary axis is rotatable to longitudinal movement of the piston allow the cylinder and having multiple locking body as separately movable locking bolts are designed.

Characterized in that the locking body as a separately movable Locking bolts are designed, can jamming or tilting during locking can be avoided. in the Difference to the previously known prior art Such locking bolts simple and inexpensive can be produced and require only a minimal installation and Control room, so that the gained space beneficial for other elements and / or tasks can be used or an overall smaller and lighter locking cylinder can be provided.

Due to the above measures are only comparatively small locking and unlocking forces needed. This allows the locking cylinder in the area the locking unit overall space-saving or be carried out more easily. Also can be characterized significantly reduced locking and unlocking times to reach. Finally, when using the separately movable locking bolt no circumferential Seals between these and the cylinder wall needed.

In this way, so a locking cylinder be provided, which is simpler and more space-saving Locking construction higher operational safety allows and has a better efficiency.

In an advantageous development it can be provided that the locking bolts move independently of each other are arranged, ie in particular without mechanical Forced coupling between the locking bolts. According to a further embodiment variant can be provided that only uses two separate locking bolts become. This eliminates the risk of tilting or Further reduce deadlocks.

According to yet another embodiment variant can be provided that the locking bolt respectively in one towards the side of the locking recesses open bearing recess of the head of the cylinder with are stored small game.

It may be of particular advantage when it comes to the Locking bolt is about cylinder pin, the preferably have a circular cylindrical outer contour. It may therefore be particularly advantageous if the Locking bolts at their free locking ends each have a conical outer contour and / or if the cylinder bolts each in a cylindrical Inner contour bearing recess with little play are stored.

According to a further embodiment variant can be provided be that the locking bolts each one to their, the respective spring associated end open to the outside Have recess in which each as a compression spring designed spring is received with a spring section and there with one of their ends at each one Supported inside surface of the respective locking bolt is, with her other end to the head of the cylinder is supported.

According to a further embodiment variant can be provided be that the locking bolts each have a circumferential Have sealing surface in the unlocking of the has respective locking bolt, and in the Unlocking position of the respective locking bolt and then under the working means in the unlocked position exerted compressive forces on a rotating Sealing surface of the head of the cylinder sealing is applied.

According to a further embodiment variant can be provided be that the sealing surface at the same time a stop surface for Limitation of an unlocking stroke of the respective Locking bolt trains.

According to a further embodiment variant can be provided be that the sealing surface in the area of the spring associated end of the locking bolt is arranged.

According to a further embodiment variant can be provided be that the sealing surface at an annular end edge of the locking bolt at the spring associated End is arranged.

According to a further embodiment variant can be provided be that the locking bolt cross-section are designed so that closed at the respective Sealing surface of sealingly abutting sealing surface of respective locking bolt leakage of the working fluid along the respective locking bolt is prevented.

According to a further advantageous embodiment variant can be provided that the locking bolts each one Passage channel, which in the locked position in the region of the locking recess, preferably in the Locking recess opens and the other end with a preferably connected as a discharge channel serving channel is, so that the fluid working fluid in one movement the respective locking bolt from its unlocked position in its locking position from the respective locking recess in the aforementioned Channel can flow.

According to a further advantageous embodiment variant can be provided that the respective passage to his the locking recess associated end of the respective locking bolt a flow area which is much smaller than an effective area of the respective locking bolt on which the fluid Working means can attack to the respective locking bolt to convert into its unlocked position.

According to a further advantageous embodiment variant can be provided that the respective passage in the respective locking bolt to form a Support and conditioning level for each as a compression spring trained spring laterally expanded.

According to a second solution thought or according to a particularly preferred embodiment of the input said locking cylinder, the invention task also by a locking cylinder with the following Characteristics solved:

The lock cylinder comprises a cylinder and a Piston, parallel by means of a fluid pressure medium to the longitudinal axis of the cylinder is movable and with a Piston thread is provided, the formation of a non-self-locking thread with a spindle thread a spindle is engaged, which is parallel to a Rotary axis arranged along the longitudinal axis of the cylinder is rotatable and the at least one outwardly open locking recess has, in the at least one by means of spring force engage a spring acted on locking body can, against a rotation about the axis of rotation of the spindle secured and axially parallel to the axis of rotation of the spindle slidably mounted on a head of the cylinder, and the spring force of the spring in a locking position is convertible, in which he in the Locking recesses of the spindle engages, so that then blocks rotation of the spindle about its axis of rotation is and wherein the locking body using a fluid working fluid against the spring force of the spring from the locking position into an unlocking position is convertible, in which the spindle about its axis of rotation is rotatable to move the piston along the Cylinder to allow, with the spindle at least is mounted two thrust bearings, one of which is preferably designed as a rolling bearing designed first thrust bearing is acting on the spindle in a first direction Axialkräfte record, and wherein a second thrust bearing destined to oppose in a second direction to the first direction acting on the spindle Axialkräfte record, and wherein the spindle relative to the cylinder is mounted axially movable and fixed with a from the second thrust bearing different support body connected, which is intended in the second To absorb axial forces acting on the spindle, and that the second thrust bearing with a in the direction of Longitudinal axis of the cylinder designed movable bearings is, by acting in the first direction spring forces a spring is applied, so that a resilient Storage of the spindle is effected.

By the above measures can even large loads be moved and / or large piston speeds be realized without it being worth mentioning Wear in the area of bearings comes, and it's an over long time safe operation of such locking cylinder guaranteed.

In this way, so a locking cylinder be provided with the space-saving design in Area of the spindle bearing and in the area of the locking unit allows a higher reliability.

According to an advantageous embodiment variant can be provided that the support body at its free end has a support surface located on an opposite Supporting surface of the head of the cylinder is supported, if the support body in the second direction on the spindle absorbs acting axial forces and preferably on the Cylinder transfers. Such an advantageous support especially in case of overload or damage occur.

According to a further advantageous embodiment can be provided that the support body at a loading the spindle with a certain limit axial force below and in the second direction on the Spindle operating axial force from the support surface the head of the cylinder is lifted, being in the lifted Condition the spindle on the second thrust bearing resilient is stored.

According to a further advantageous embodiment can be provided that the support body at a Actuation of the spindle in the second direction with an overload axial force that is equal to or greater than as the limit axial force on the support surface of the head of the Cylinder supported, whereby the overload axial forces be transferred to the cylinder or compensated there.

According to a further advantageous embodiment can be provided that upon application of the spindle with the overload axial force and starting from the lifted state of the support body, in which the spindle is acted upon by the operating axial force, the Support body, the second thrust bearing and the spindle opposite to that of the spring on the second Thrust bearing exerted spring forces in the second direction be moved axially until the support body on the Support surface of the head of the cylinder rests, so then acting on the spindle in the second direction Overload axial forces from the support body to the cylinder be transferred or compensated there.

According to a further advantageous embodiment can be provided that the support body as a cylinder bolt is designed.

According to a further advantageous embodiment can be provided that the support body coaxial with the axis of rotation the spindle is arranged.

According to a further advantageous embodiment can be provided that the second thrust bearing on the Support body is added.

According to a further advantageous embodiment can be provided that the second thrust bearing as a needle bearing is designed.

According to a further advantageous embodiment can be provided that the second thrust bearing one opposite a bearing capacity of the first thrust bearing smaller Carrying capacity.

According to a further advantageous embodiment can be provided that the first thrust bearing a first Ring bearing forms with a first bearing diameter and that the second thrust bearing with a second ring bearing forming a second supporting diameter, the smaller is considered the first bearing diameter of the first Ring bearing.

According to a further advantageous embodiment can be provided that the spring with a plate spring is designed.

According to a further advantageous embodiment can be provided that the spring under training of a Disk spring package is designed with several disc springs.

According to a further advantageous embodiment can be provided that the plate spring or the disc springs is received on the support body or are.

According to a further advantageous embodiment can be provided that the support body, the thrust bearing and the spring is arranged coaxially with the axis of rotation of the spindle are.

According to a further advantageous embodiment can be provided that the locking body as a locking bolt is designed.

According to a further advantageous embodiment can be provided that several locking body are provided and that the support body, the second Thrust bearing and the spring in a projection into one formed perpendicular to the axis of rotation of the spindle projection plane within a the locking body to Rotary axis of the spindle towards the inside limiting Projection are arranged, so "between" the Locking bodies.

According to a further advantageous embodiment variant can be provided that several locking body are provided, which are preferably elongated, in particular separately movable locking bolts are designed.

According to another idea or according to a solution Another particularly preferred embodiment of the The aforementioned locking cylinder is the Invention task also by a locking cylinder solved with the following features:

The lock cylinder comprises a cylinder and a Piston, using a two sides of the piston in a first working chamber and a second working chamber deliverable fluid pressure medium parallel to the longitudinal axis of the cylinder is movable, and that with a piston thread that is under formation of a non-self-locking Thread with a spindle thread of a spindle in Engaging, which is parallel to the longitudinal axis of the Cylinder arranged axis of rotation is rotatable and the at least one outwardly open locking recess in which at least one by means of a spring force Spring can engage engaged locking body, the against rotation about the axis of rotation of the spindle secured and firmly connected to the cylinder, however is mounted relative to this movable, and the help the spring force of the spring in a locking position is convertible, in which he is in the locking recess the spindle engages, so that then a rotation of the Spindle is blocked around its axis of rotation, and where the Locking body using a fluid working medium against the spring force of the spring from the locking position in an unlocking position can be converted, in which the spindle is rotatable about its axis of rotation about one To allow movement of the piston along the cylinder and control means for controlling the movement of the Piston and the locking body or the locking body are provided, and wherein at least one first load-holding lowering brake means with the first working chamber fluid-connected and that at least a second Load-holding lowering brake means with the second working chamber fluidly connected, wherein the at least two load-holding lowering brake means cause that when the Piston on his first page with the first Working chamber pressure fluid under training a working pressure, which is a displacement of the piston in a first direction causes, simultaneously in the second Working chamber on the second side of the piston through the pressure medium located in the second working chamber applied counter-pressure acts, which is smaller than that Working pressure in the first working chamber, leaving a uncontrolled advance of the piston in the first direction avoided, and vice versa, when the Piston on its second side with the second Working chamber pressure fluid under training a working pressure, which is a displacement of the piston in a second direction opposite to the first direction causes, at the same time in the first working chamber at the first side of the piston one through in the first Working chamber located pressure medium applied backpressure acts, which is smaller than the working pressure in the second Working chamber, so that an uncontrolled advance of the Piston is avoided in the second direction, and where the load-holding lowering brake means at a wanted Pressure relief for the purpose of holding the piston in one desired stroke position a return flow of the pressure medium lock out of both working chambers, allowing the piston to pass through located in the working chambers pressure medium in the desired stroke position is held.

This allows the piston as it moves along the Cylinder between the working in the working chambers Press quasi "clamp", leaving an uncontrolled Leading or uncontrolled movements of the piston with Safety can be avoided. Furthermore, it can both high and highest piston speeds driven without causing cavitation effects in the area of Piston seal and / or the piston rod comes, as well small to smallest piston speeds, d. H. it can can advantageously be driven in "creep".

In this way, so a locking cylinder provided with extended application and Possible applications as well as longer service life a higher Operational safety allows.

According to a preferred embodiment can be provided be that of the load-holding lowering brake means controlled backpressure depending on the respective one Move the piston along the cylinder Working pressure is controlled.

According to a preferred embodiment can be provided be that of the load-holding lowering brake means controlled backpressure depending on the respective one Move the piston along the cylinder Working pressure is controlled, so with increasing Working pressure of the simultaneously acting back pressure decreases.

According to a preferred embodiment can be provided be that the back pressure is inversely proportional to the Working pressure is controlled.

According to a preferred embodiment can be provided be that the load-holding lowering brake means each one first inlet for the pressure medium, an outlet for the Pressure medium and a control connection for the pressure medium wherein the inlet of the first load-holding lowering brake means fluidly connected to the first working chamber and the inlet of the second load-holding lowering brake means is fluidly connected to the second working chamber, and wherein the outlet of the first load-holding lowering brake means to the control terminal of the second load-holding lowering brake means fluidly connected and the outlet of the second load-holding lowering brake means with the control terminal the first load-holding lowering brake means is fluidly connected, and wherein with the inlet and the outlet of the respective Load-holding lowering brake means each a Rückströmsperrmittel fluidly connected, each having a flow of the Pressure medium from the outlet to the inlet of the respective Load-holding lowering brake agent allows, but one opposite direction respectively locks, and that optionally the outlet of the first load-holding lowering brake means and thus the control terminal of the second Load-holding lowering brake means or the outlet of the second Load-holding lowering brake means and thus the control connection the first load-holding Senkbrems agent with pressure medium be acted upon to a movement of the piston in the first direction or in the second direction due to the respective working pressure and at the same time Training the respective back pressure, the second Load-holding lowering brake means or via the first load-holding lowering brake means depending on the one at the respective Control port acting pressure to effect.

According to a preferred embodiment can be provided be that optionally the outlet of the first load-holding lowering brake means or the outlet of the second load-holding lowering brake means in fluid communication with the locking body or the locking bodies can be brought, so that upon expelling the outlet of the first Load-holding lowering brake means or the outlet of the second Load-holding lowering brake fluid with pressure medium, this the Supplied locking body or the locking bodies is to this or this in his or her unlocking position to convict.

According to a preferred embodiment can be provided be that between the outlet of the first load-holding lowering brake means and the outlet of the second load-holding lowering brake means at least one Rückströmsperrmittel is arranged, when an admission of the outlet the first load-holding lowering brake means with pressure medium a Pressure fluid flow to the outlet of the second load-holding lowering brake means prevented and vice versa an admission of the outlet of the second load-holding lowering brake means with pressure medium, a pressure medium flow towards the outlet of the first load-holding lowering brake means prevented, and in both cases a supply of the Pressure medium to the locking body or the locking bodies so that this or this in his or their unlocked position is or will be transferred.

According to a preferred embodiment can be provided be that the Rückströmsperrmittel a first inlet for the pressure medium, a second inlet for the Having pressure medium and an outlet for the pressure medium, wherein the first inlet of the Rückströmsperrmittels with the Outlet of the first load-holding lowering brake fluidly connected and wherein the second inlet of the Rückströmsperrmittels with the outlet of the second load-holding lowering brake means fluidly connected, and wherein the first inlet of the Rückströmsperrmittels and the second inlet of the Rückströmsperrmittels connected to each other via a fluid channel are in the one with the outlet of the Rückströmsperrmittels connected fluid channel opens at a confluence point, so that from the confluence a first channel part of the Fluid channel and a second channel part of the fluid channel branches off, and wherein a locking member for shutting off the first Channel part or the second channel part is provided, and wherein in the shut-off state of the second channel part of the first inlet of the Rückströmsperrmittels, the first Channel part and the outlet of the Rückströmsperrmittels fluid-connected, so that a pressure medium flow both from the first inlet of the Rückströmsperrmittels to the outlet of the Rückströmsperrmittels and the outlet the Rückströmsperrmittels to the first inlet of the Rückströmsperrmittels is permitted, and vice versa in the closed state of the first channel part of the second Inlet of Rückströmsperrmittels, the second channel part and the outlet of the non-return means are fluidly connected, so that a pressure medium flow both from the second Inlet of Rückströmsperrmittels to the outlet of the Rückströmsperrmittels and from the outlet of the Rückströmsperrmittels to the second inlet of the Rückströmsperrmittels is allowed.

According to a preferred embodiment can be provided be that the Rückströmsperrmittel a first inlet for the pressure medium, a second inlet for the Having pressure medium and an outlet for the pressure medium, wherein the first inlet of the Rückströmsperrmittels with the Outlet of the first load-holding lowering brake fluidly connected and wherein the second inlet of the Rückströmsperrmittels with the outlet of the second load-holding lowering brake means fluidly connected, and wherein the first inlet of the Rückströmsperrmittels and the second inlet of the Rückströmsperrmittels connected to each other via a fluid channel are in the one with the outlet of the Rückströmsperrmittels connected fluid channel opens at a confluence point, so that from the confluence a first channel part of the Fluid channel and a second channel part of the fluid channel branches off, and wherein a first locking member for shutting off the first channel part and a second locking member for shutting off the second channel part is provided, which is the first Channel part and the second channel part with respect to a Pressure fluid flow from the outlet of the Rückströmsperrmittels to the first inlet of the Rückströmsperrmittels and the Shut off the second inlet of the Rückströmsperrmittels and the a fluid flow from the first inlet of the Rückströmsperrmittels to the outlet of the Rückströmsperrmittels and from second inlet of the Rückströmsperrmittels to the outlet of Allow Rückströmsperrmittels.

According to a preferred embodiment can be provided be that the working fluid or the pressure medium the Supplied locking body or the locking bodies is to this or this in his or her unlocking position to convict and that at the same time the Pressure medium either the first working chamber or the second working chamber is supplied to a movement of the Piston in the first direction or in the second direction to effect.

According to a preferred embodiment can be provided be that the work equipment or the pressure medium first the locking body or the locking bodies is fed to this or these in his or her To transfer unlocking position and that then the Pressure medium either the first working chamber or the second working chamber is supplied to a movement of the Piston in the first direction or in the second direction to effect.

According to a preferred embodiment can be provided be that the respective Rückströmsperrmittel a Locking member for preventing a pressure fluid flow of the Inlet to the outlet of the respective load-holding lowering brake means characterized by the spring forces of a spring is acted upon, so that opening the Rückströmsperrmittels and thus a flow of pressurized fluid from the outlet to the inlet of the respective load-holding lowering brake means only after exceeding a limit pressure of the pressure medium whose value is determined by a spring characteristic of the depends on each spring.

It is understood that the above measures are in the context the feasibility of a locking cylinder of The aforementioned type can also be combined as desired can, to a locking cylinder with accordingly To be able to provide combined advantages.

Further aspects, features and advantages of the invention can be taken from the following description part in which two preferred embodiments of the Invention are described in more detail with reference to the figures:

Fig. 1

einen Längs-Querschnitt durch einen erfindungsgemäßen Verriegelungszylinder;

Fig. 2

einen vergrößerten Ausschnitt des Querschnitts gemäß Figur 1 im Bereich des dort rechts dargestellten Verriegelungsbolzens;

Fig. 3

einen Teilquerschnitt des Verriegelungszylinders längs der Schnittlinie 3-3 in Figur 1 zur Verdeutlichung der Zahl und Anordnung der Verriegelungsausnehmungen;

Fig. 4

einen vergrößerten Längs-Querschnitt im Bereich eines alternativen Ausführungsbeispiels eines Verriegelungsbolzens;

Fig. 5

einen hydraulischen Schaltplan gemäß einer ersten Ausführungsvariante der Erfindung;

Fig. 6

einen hydraulischen Schaltplan gemäß einer zweiten Ausführungsvariante der Erfindung.

Show it:

Fig. 1

a longitudinal cross section through a locking cylinder according to the invention;

Fig. 2

an enlarged section of the cross section of Figure 1 in the region of the locking bolt shown there on the right;

Fig. 3

a partial cross section of the locking cylinder along the section line 3-3 in Figure 1 to illustrate the number and arrangement of the locking recesses;

Fig. 4

an enlarged longitudinal cross section in the range of an alternative embodiment of a locking bolt;

Fig. 5

a hydraulic circuit diagram according to a first embodiment of the invention;

Fig. 6

a hydraulic circuit diagram according to a second embodiment of the invention.

The locking cylinder 20 shown in Figure 1 comprises a cylinder 21 and a longitudinally displaceable therein mounted piston 22. The piston 22 is opposite to Cylinder inner wall sealed by a ring seal 68 and is on its in the direction of the longitudinal axis 29 of the Cylinder 21 facing away from each other pages 44, 46 by a fluid pressure medium, preferably oil, acted upon, to a pressure fluid assisted movement of the piston 22 in one as a second direction or unlocking designated retraction direction 27 or in one as well first direction designated extension direction 28 to enable.

The piston 22 is fixedly connected to a piston rod 23, which, starting from its end face 44 coaxial with Cylinder longitudinal axis 29 extends. The cylinder 20 is on its the free end 67 of the spindle 35 associated side by a piston rod 23 receiving the lid 30th completed. On its other side is the cylinder 21st firmly connected to a step-shaped projection 66. This is in turn by a cylinder bottom 53 forming Cover or head 31 completed.

The piston 22 forms a projection 32, the rotation with the Piston rod 23 is connected. The piston 22 is as a designed tubular body and also has a Piston thread designated internal thread 34. This is engaged with a spindle thread as well designated external thread 36 of a spindle 35, on which the piston 22 is guided. The internal thread 34 of the piston 22 and the external thread 36 of the spindle 35 are preferably Designed as an eight-speed trapezoidal steep thread that together form a non-self-locking thread 37.

For attachment of the locking cylinder 20, the Piston rod 23 at its free end one here with an eyelet designed fastener 25, and a corresponding designed fastener 26 is opposite attached to the head 31 of the cylinder 21.

The pressure medium is via the channels 48 and 49 on both Pages 44 and 46 of the piston 22 in a first working chamber 45 and in a second working chamber 33 can be fed to a Movement of the piston 22 along the cylinder 21 in Retraction direction 27 or in the extension 28 to reach can. In this case, the first working chamber 45 against the second working chamber 33 via the annular seal 68 of the Piston 22 sealed.

In the area of the free end 67 of the spindle 35 away pointing end 77 of the spindle 35, this rotation with connected to a flange-shaped projection 65. This one points in the Area of his cylinder bottom end a cross or at right angles to the axis of rotation 43 of the spindle 35 extending, here annular wall portion 79. This is pointing to the free end 67 of the spindle 35 Side through a first thrust bearing 120, here in the form of a first ring bearing 127, here as a needle bearing 138th is formed at a support and investment level of Cylinder approach 66 stored. This as a rolling bearing 137 designed ring bearing 127 serves to that in the extension direction 28 acting on the spindle 35 axial forces take. To the in the retraction 27th opposite to the extension direction 28 on the spindle To be able to absorb 35 acting axial forces are two Measures taken:

To record during a normal operation of the Locking cylinder 20 in the first direction 28 on the Spindle 35 acting operating axial forces, is a second Thrust bearing 121 in the form of a second ring bearing 130th provided at the head end 77 of the spindle 35th is arranged. This thrust bearing 121 is also as a Rolling 122 designed in the form of a needle bearing 123. It is fixed on a coaxial with the axis of rotation 43 of the spindle 35 with the spindle 35 connected support body 124 in the form a cylinder pin 125 is added, extending in the direction the cylinder bottom or head 31 of the cylinder 21st extends and the coaxial with the axis of rotation 43 spindle 35th is arranged.

At the needle bearing 123 closes in the retraction 27th a plate spring package 135, which consists of several disc springs 134, 136 exists. In the embodiment shown are five disc springs 134 and five disc springs 136 provided. In this case, the disc springs 134 and the disc springs 136th in each case alternately one after the other, preferably in such a way arranged that in each case the spring travel of each plate spring 134, 136 for a resilient mounting of the spindle 35 for Available. The disc springs 134, 136 are in terms their spring characteristics and arrangement chosen such that in the regular driving operation, when the piston 22 in Einfahrrichtung 27 is moved, it does not over the self-locking thread 37 and the spindle 35 transmitted collected dynamic resulting forces, d. H. be compensated so that the support body 124 always from lifted off the head 31 of the cylinder bottom of the cylinder 21 is.

However, if the piston 22 in the opposite direction, d. H. extended in the extension 28, acts on the spindle 35, a resultant axial force in the Extension direction 28, so that even with this piston movement the support body 124 is always lifted off the head 31.

Otherwise, in the case of holding the piston 22nd in a desired stroke position. Because then, how will will be explained in more detail below, the piston 22 of Pressure medium, which in the two working chambers 33 and 45 and with these fluid-connected channels 49 and 48th is held, "clamped", so even under allowable high static loads coming from the locking cylinder 20 are held or moved, the Support body 124 always from the head 31 of the cylinder 21st is lifted off. In this case, so using the Locking cylinder 20 to be held static load and in this regard, transferred to the spindle 35 Axialkräfte substantially over the piston 22 and the this pressurizing pressure and on the adjacent Cylinder walls added.

However, if a claim occurs, so z. Legs Leakage in the area or a break in a pressure medium line occurs, 27 acting in the retraction direction Overload axial forces occur that of the small Needle bearing 123 no longer received without destruction can be. Because this second needle bearing 123 has a relative to the carrying capacity or the supporting diameter of the first needle bearing 138 smaller capacity or smaller load-bearing diameter to meet the requirements to a space-saving design of the locking cylinder 20 in the locking and storage area too suffice. The wear the used disc springs 134 and 136 bill, so that when exposed to the overload axial forces a displacement of the spindle 35 in the retraction direction 27 while simultaneously squeezing the Disc springs 134, 136 occurs until the support body 124 with the existing at its free end support surface 129 the opposite support surface 131 of the head 31 of the Cylinder rests. The support body 124 is therefore supported then there, so that the acting overload axial forces then from the spindle 35 via the support body 124 on the Head 131 of the cylinder 21 are transferred without that the needle bearing 123 would be damaged.

Due to the arrangement and the selected spring characteristics of Disc springs 134, 136 is therefore a certain force given, that of a certain limit axial force corresponds, when it falls below the support body 124th is lifted and when they reach or exceed a displacement of the spindle 35 together with the Support body 124 in retraction 27 occurs until the Support body 124 bears against the head 31 of the cylinder 21.

The flange-shaped projection 65 is at the transversely to the Fulcrum 43 of the spindle 35 extending wall portion 79 with here a total of eight locking recesses 38.1 to 38.8 provided, which open to the cylinder bottom 53 toward the outside are. The locking recesses 38.1 to 38.8 are in each equal angular distances from each other on a imaginary circumference circle arranged such that each two Locking recesses arranged diametrically opposite each other are and therefore on a rotation axis 43 of the spindle 35th containing straight lines are arranged. Each locking recess 38 is conically tapering inwards Wall parts 70 designed and used to accommodate yourself outwardly conically tapered wall parts 72 of Locking bolt 40, 140. This is the conical tapered wall portions 72 having free end 57 of the respective locking bolts 40, 150 preferably such on the locking recesses 38 in the area of their conically tapered wall parts 70 designed coordinated, that a Durchströmspalt 71 formed for the pressure medium is. This Durchströmspalt 71 is in fluid communication with a gap 91 in the region of the radial edges both the flange-shaped projection 65 as well as this opposite part of the head 31 of the cylinder 21st is arranged. This gap 91 is in fluid communication with a switching channel 47, which in turn in fluid communication with channels 48 and 49 can be brought, via which the piston 22nd on its respective pages 44 and 46 with pressure medium can be acted upon.

A first embodiment of a locking bolt 40 is shown in Figures 1 and 2 and a second embodiment of a locking bolt 140th is illustrated in FIG. The locking bolt 40 is in contrast to the locking bolt 140 in Area of its free end 57 cross-sectionally closed designed while the locking bolt 140 as a hole nozzle 90 with an open to his free end 57 and concentric with its longitudinal axis 74 designed passageway 54 is provided. Except for this passage 54, however, the locking bolts 40 and 140 are identical designed, wherein like reference numerals like elements affect.

Each locking bolt 40, 140 is preferred as one elongated cylinder pin 125 rotationally symmetrical to designed its longitudinal axis 74. Every locking bolt 40, 140 has a circular cylindrical outer contour 50 and a circular cylindrical inner contour, so is as a Rotational hollow body designed. Every locking bolt 40, 140 also has a circular cylindrical recess 92 on, with parallel to the longitudinal axis 74 of the respective Locking bolt 40, 140 delimiting wall parts is designed and the to the the head 31 of the cylinder 21st opposite end 56 is open to the outside. These Recess 92 serves for receiving and lateral support a designed as a compression spring spring 39. This is in mounted state with a spring portion 93 in the Recess 92 recorded. In this case, the spring 39 is supported with one of its ends 95 on an inner surface 94 of a radially inwardly extending support and conditioning stage 60 of the locking bolt 40, 140 from. The other end 96 of the Spring 39 is supported on an inner surface of a corresponding one Support and conditioning stage 76 of the head 31 of the Cylinder 21 off.

At an axial distance from the inner surface of the support and Investment level 76 and offset in the extension 28, is a radially outwardly extending stop and Mating surface 98 for the locking bolt 40, 140 provided perpendicular to the bearing recess 75th limiting wall parts is arranged. Every locking bolt 40, 140 has at its head or spring side End 59 a ring end edge 99, which with a circumferential ring-sealing surface 97 is designed and the in Unlocking 27 of the respective locking bolt 40, 140 points. This ring sealing surface 97 is located sealing on the likewise circumferential stop and Mating surface 98 of the head 31 of the cylinder 21, when the respective locking bolt 40, 140 after a Actuation with the pressure medium in unlocking 27 exerted pressure forces in his Unlocking position has been transferred. Under the then effective pressure forces a sealing is achieved there, so no leakage of pressure fluid along the Outer surfaces of the respective locking bolt 40, 140th occurs. In addition, the stop and sealing counter surface limits 96 advantageous the respective Entriegelungshub the Locking bolt 40, 140.

Each locking pin 40, 140 is with little play in the cylindrical inner contour 98 having a bore or bearing recess 75 parallel to the axis of rotation 43, the Spindle 35 slidably mounted, so it can be based on the locking position shown in Figures 1, 2 and 4 41 in the extension or unlocking direction 28 using the pressure medium against the spring forces of the spring 39 in its unlocked position can be moved, or can vice versa after pressure relief in the area of its free Locking end 57 of its unlocked position automatically, d. H. by the spring 39th on the respective locking bolt 40, 140 exerted Return spring forces, again in its locking position 41 are transferred. The bearing recess 75 thus has an inner diameter that is slightly larger than the outer diameter of the locking bolt 40, 140th

In contrast to those shown in Figures 1 and 2 Locking bolt 40 is the illustrated in Figure 4 Locking bolt 140 designed as a hole nozzle 90 and has at its free end 57, that in the in FIG. 4 shown locking position 41 in the locking recess 38 projects, a central passageway 54. This passageway 54 is coaxial with the longitudinal axis 74 of the locking bolt 140 is arranged. The passageway 54 has a comparatively small flow cross section and goes towards his other end 59 in a likewise designed with cylindrical wall parts Channel section 78 via, which has a larger flow area having. The channel part 78 is in turn under training the support and abutment surface 60 in a recess 92 of the larger channel diameter 61 over, the slightly larger is as the outer diameter 62 in the above Recess 92 received spring 39. This is the Compression spring one end at the support and conditioning stage 60 of Locking bolt 140 and supports the other end the supporting and conditioning stage 76 of the lid or head 31 of the cylinder 21.

The locking pin 140 has at its free end 57th a perpendicular to its longitudinal axis 74 arranged Active surface 58 on which attack the fluid pressure medium can to the locking pin 140, starting from the in Figure 4 shown locking position 41 in a Unlock release position, in which he except Engagement with the locking recesses 38.1 to 38.8 is, so a rotation of the spindle 35 in a rotational direction 51 or an opposite direction of rotation 52 is not more blocked. The effective area 58 is much larger Flow cross section of the passage channel 54 in the area the free end 57 of the locking bolt 40, 140th As a result, a secure unlocking of the locking bolt 40, 140 allows. It can also be at a Pressure relief in the locking recesses 38, be it wanted, for the purpose of fixing the piston 22 with its piston rod 23 in a certain stroke position, or be it unintentional, for example in the event of a leak or in the event of total failure of the hydraulic system, the Locking bolt 40, 140 caused by the spring 39 exerted forces in its locking position 41st to be moved. It can in the case of locking bolts 140 located in the associated locking recess 38th located pressure medium through the passage 54 of the Locking bolt 140 through to the relief channel serving channel 55 flow. In contrast to is when using the locking pin 40 in the Movement from its unlocked position to the locked position 41 located in the associated locking recesses 38 located oil via the switching channel 47th and via the Rückströmsperrmittel 160 either in the Supply channel 86 or displaced in the return channel 87, depending after, in which position the locking member 171 of as a shuttle valve designed Rückströmsperrmittels 160th located.

In Figures 5 and 6 are hydraulic circuit diagrams illustrated in which particularly advantageous Control means and routes are used. The circuit According to the circuit diagram shown in Figure 5 can be advantageous for operation and operation of a locking bolt 40 equipped locking cylinder 20 is used become. It is understood, however, that the from the Wiring diagram according to Figure 5 resulting switching or Control elements also advantageous in connection with the used in Figure 4 locking bolt 140 can be.

A particularly advantageous control of the locking cylinder 20 can be achieved with the circuit according to FIG. 5, because this circuit and the control means used there make it possible that the pressure medium first the Locking bodies 42 is supplied to these in their To transfer unlocking position and that then the Pressure medium optionally the first working chamber 33 or the second working chamber 45 is supplied to a movement of the piston 22 in the first direction 28 or in the second To effect direction 27. This can reduce the wear in the Area of the locking bolt 40 and in the area of Locking recesses 38 are minimized and it can not jamming the locking bolts 40, come especially at low switching pressures.

In contrast, in the circuit according to FIG. 6 provided that the working fluid or the pressure medium the Locking bodies 142 is supplied to these in their Release unlocking position and that at the same time the pressure medium optionally the first working chamber 33 or the second working chamber 45 is supplied to a Movement of the piston 22 in the first direction 28 or in to effect the second direction 27.

Certain essential switching or control elements, in conjunction with both circuit variants can be used advantageously, are closer below described:

There are two each as load-holding lowering brake means 150.1, 150.2 designated load-holding lowering brake valves provided the effect that upon application of the piston 22 on its first side 46 with that in the first chamber 33rd located pressure medium to form a working pressure, the displacement of the piston 22 in a first Direction 28 causes, simultaneously in the second working chamber 45 on the second side 44 of the piston 22 a through the pressure medium located in the second working chamber 45 applied counter-pressure acts, which is smaller than that Working pressure in the first working chamber 33, leaving a uncontrolled advance of the piston 22 in the first Direction 28 is avoided, and vice versa at Actuation of the piston 22 on its second side 44th with that in the second working chamber 45 located Pressure medium to form a working pressure, the a displacement of the piston 22 in a second direction 27th opposite to the first direction 28 causes simultaneously in the first working chamber 33 at the first Side 46 of the piston 22 by a in the first Working chamber 33 located pressure medium exerted Counterpressure acts, which is smaller than the working pressure in the second working chamber 45, leaving an uncontrolled Advancing the piston 22 in the second direction 27 avoided and wherein the load-holding lowering brake means 150.1, 150.2 at a desired pressure relief for the purpose of holding the piston 22 in a desired stroke position a Return flow of the pressure medium from both working chambers 33, 45 lock so that the piston 22 through the into the working chamber 33, 45 located pressure medium in the desired Lift position is held securely.

Each load-holding counterbalance valve 150.1, 150.2 has a Inlets 153.1, 153.2, an outlet 154.1, 154.2 and one Control connection 155.1, 155.2 for the pressure medium, wherein the inlet 153.1 of the first load-holding lowering valve 150.1 is fluidly connected to the first working chamber 33 and wherein the inlet 153.2 of the second load-holding lowering valve 150.2 with the second working chamber 45 fluidly connected, and wherein the outlet 154.1 of the first Load-holding lowering brake valve 150.1 with the control connection 155.2 of the second load-holding lowering valve 150.2 fluidly connected and wherein the outlet 154.1 of the second Load-holding lowering brake valve 150.2 with the control connection 155.1 of the first load-holding lowering valve 150.1 fluid-connected, and with the inlet 153.1, 153.2 and the outlet 154.1, 154.2 of the respective load-holding lowering brake valve 150.1, 150.2 each a backpressure blocking agent 156.1, 156.2 fluidly connected, each one Flow of the pressure medium from the outlet 154.1, 154.2 to the inlet 153.1, 153.2 of the respective load-holding lowering valve 150.1, 150.2 allows, but in opposite direction respectively locks, and that optionally the outlet 154.1 of the first load-holding lowering valve 150.1 and thus the control terminal 155.2 of second load-holding counterbalance valve 150.2 or the outlet 154.2 of the second load-holding lowering valve 150.2 and so that the control terminal 155.1 of the first load-holding lowering valve 150.1 acted upon by pressure medium are to move the piston 22 in the first direction 28 or in the second direction 27 due to the respective Working pressure and with simultaneous training of the respective back pressure, via the second load-holding Senkbrems valve 150.2 or via the first load-holding lowering valve 150.1, preferably depending on the the respective control port 155.1, 155.2 acting pressure to effect.

In each case between the outlet 154.1 of the first load-holding Senkbrems valve 150.1 and the outlet 154.2 of the second Load-holding lowering brake valve 150.2 is at least one Rückströmsperrmittel 160, 161 arranged at a Actuation of the outlet 154.1 of the first load-holding Senkbrems valve 150.1 with pressure medium a pressure medium flow to the outlet 154.2 of the second load-holding lowering valve 150.2 prevented and vice versa in a Actuation of the outlet 154.2 of the second load-holding lowering valve 150.2 with pressure medium a pressure medium flow to the outlet 154.1 of the first load-holding Senkbrems valve 150.1 prevents and in both cases a Supply of the pressure medium to the locking body 42, 142nd allows, so that these in their unlocked position can be transferred.

It is further provided that the Rückströmsperrmittel 160, 161 a first inlet 164 for the pressure medium, a second inlet 165 for the pressure medium and an outlet 166 for the pressure medium, wherein the first inlet 164 of the respective Rückströmsperrmittels 160, 161 with the Outlet 154.1 of the first load-holding lowering valve 150.1 fluidly connected, and wherein the second inlet 165 of the respective Rückströmsperrmittels 160, 161 with the outlet 154.2 of the second load-holding lowering valve 150.2 fluidly connected, and wherein the first inlet 164 of the respective Rückströmsperrmittels 160, 161 and the second Inlet 165 of the respective Rückströmsperrmittels 160, 161st are connected to each other via a fluid channel 167, in the one with the outlet 166 of the respective Rückströmsperrmittels 160, 161 connected fluid channel 167 at a Occluence 168 opens so that from the confluence 168 a first channel part 169 of the fluid channel 167 and a second channel portion 170 of the fluid channel 167 branches off.

In the circuit according to Figure 5 is also a locking member 171 for shutting off the first channel part 169 or the second channel portion 170 is provided, and wherein in the locked State of the second channel part 170 of the first inlet 164 of the Rückströmsperrmittels 160, the first channel part 169th and the outlet 166 of the non-return valve 160 fluid-connected, so that a pressure medium flow both from the first inlet 164 of Rückströmsperrmittels 160th to the outlet 166 of Rückströmsperrmittels 160 and the Outlet 166 of Rückströmsperrmittels 160 to the first Inlet 164 of the non-return valve 160 is allowed, and vice versa, in the locked state of the first Channel portion 169, the second inlet 165 of the Rückströmsperrmittels 160, the second channel part 170 and the outlet 166 of Rückströmsperrmittels 160 are fluidly connected, so that a pressure medium flow both from the second inlet 165 of the Rückströmsperrmittels 160 to the outlet 166 of Rückströmsperrmittels 160 as well as the inlet 164 of the Rückströmsperrmittels 160 to the second inlet 165 of the Rückströmsperrmittels 160 is allowed.

In the circuit according to FIG. 5, it is further provided that the respective Rückströmsperrmittel 156.1, 156.2 a Blocking member 173.1, 173.2 to prevent a flow of pressure medium from the inlet 153.1, 153.2 to the outlet 154.1, 154.2 of the respective load-holding lowering brake means 150.1, 150.2, which by spring forces of a spring 174.1, 174.2 is applied, so that opening the Rückströmsperrmittels 156.1, 156.2 and thus a pressure medium flow from the outlet 154.1, 154.2 to the inlet 153.1, 153.2 of the respective load-holding lowering brake means 150.1, 150.2 only after exceeding a limit pressure of the Pressure medium is possible, its value of one Spring characteristic of each spring 174.1, 174.2 depends. These springs 174.1 and 174.2 are also good in FIG the lower ends of the two load-holding lowering valves 150.1, 150.2 can be seen.

In contrast to the circuit of Figure 5 can be provided according to a circuit according to Figure 6, that a first locking member 172.1 for shutting off the first Channel part 169 and a second locking member 172.2 to Shut off the second channel part 170 is provided, the the first channel part 169 and the second channel part 170 with regard to a flow of pressure medium from the outlet 166 of the Backflow blocking means 161 to the first inlet 164 of the Rückströmsperrmittels 161 and the second inlet 165 of the Rückströmsperrmittels 161 shut off and a pressure fluid flow from the first inlet 164 of the Rückströmsperrmittels 161 to the outlet 166 of Rückströmsperrmittels 161 and from the second inlet 165 of the Rückströmsperrmittels 161 to Allow outlet 166 of the Rückströmsperrmittels 161.

Hereinafter, the operation of the lock cylinder 20 described in more detail:

In the rest position of the example shown in FIG Locking cylinder 20, ie while holding the piston 22nd and the piston rod 23 in a desired stroke position, this is already through the use of the load-holding lowering brake valves 150.1, 150.2 hydraulically secured. These are via the channel 48 and the channel 49 with the pressure medium working spaces 45 and 33 of the cylinder 21 fluidly connected, the pressurization of the piston 22 on his to the piston rod end side facing 44 and / or its side facing the cylinder bottom 53 side 46 enable.

Allow the load-holding lowering brake valves 150.1 and 150.2 So already a backup of the respective stroke position of the Piston 22 with the piston rod 23 relative to the cylinder 21, both when using the locking cylinder 20 for the transmission of compressive forces as well as for Transmission of tensile forces.

In addition to the hydraulic backup using the Load-holding lowering brake valves 150.1, 150.2 is one mechanical securing of the locking cylinder 20 via the locking unit 56 possible. This additional mechanical security engages especially when a Leakage or failure or similar damage to the hydraulic system occurs. Because then they attack Locking bolts 40, 140 in the locking recesses 38, so that a positive and bidirectional Locking the spindle 35 and thus of the piston 22 in the given stroke position is given. These intervention or Blocking position of the cylinder bolts 40, 140 is in the Moment reaches, in which an unwanted, in the Channels 48 or 49 and thus also in the switching channel 47th impacting pressure relief occurs. Because then the will respective locking bolts 40.1, 40.2; 140.1, 140.2 by the mechanical force of the compression springs 39 against the pressed previously rotating flange-shaped projection 65, until the respective locking bolt 40.1 and 40.2 or 140.1 and 140.2 in the next possible locking recess 38 engages and thereby further rotation of the Spindle 35 blocked.

The operation of the lock cylinder will be described below 20 using the circuit shown in Figure 5 described: For example, a movement of the piston 22 and thus the piston rod 23 relative to the cylinder 22 in the To reach extension direction 28, the here with Flow channel 86 designated channel with pressure medium charged, d. H. it will be using one in the figures not shown pump through the flow channel 86 the Supplied pressure medium.

Up to a certain pressure, that of the spring characteristic the spring 174.1 of the backflow 156.1 depends Pressure medium initially not in the channel 49 and thus not get into the working space 33, but passes first via the first inlet 164 into the first channel part 169 of the as a shuttle valve designed Rückströmsperrmittels 160, whereby the blocking means 171 under opening a Flow path via the discharge point 168 in the Fluid channel 167 and from there via the outlet 166 in the Switching channel 47 under substantially simultaneously Closing the second channel part 165 in the in FIG. 5 Locking position shown on the left is moved.

At the same time to the control terminal 155 of the second Load-holding counterbalance valve 150.2 leading channel 88.1 with Applied pressure medium. However, it does pending pressure medium pressure still no opening of the second Load-holding lowering brake valve 150.2. Because an opening of Load-holding lowering brake means 150.1 and 150.2 are counteracted adjustable spring forces of a respective spring 80.1 or 80.2. Consequently, the respective load-holding lowering brake means opens 150.1 and 150.2 only from a certain, on the respective control connection 155.1 or 155.2 pending Fluid pressure, depending on the springs 80.1 or 80.2 set spring forces or spring characteristics. These spring forces or spring characteristics are preferably adjusted so that the load-holding lowering brake means 150.1, 150.2 open only when the Rückströmsperrmittel 156.2 or 156.1 opens, d. H. here, when the respective Rückströmsperrventil against the Spring force of the respective spring 174.2 or 174.1 opens to a movement of the piston 22 in the extension direction 28 and to effect in the retraction direction 27.

The pressure medium then flows through the first then Switching channel 47 to the pressure medium spaces in the region of free ends 57 of the locking bolts 40 and causes that these from the locking position 41 shown in FIG the direction 27 is transferred to its unlocked position become. Once the sealing surfaces 97 of the locking bolt 40 abut against the mating surfaces 98, it gets lost a further supply of pressure medium in the flow channel 86 there to another pressure rise, which leads that the spring-loaded Rückströmsperre 156.1 opens. Then can the pressure medium through the channel 49 in the first Working chamber 49 flow to a movement of the piston 22nd and thus the piston rod 23 in the extension direction 28 too cause.

At the same time that is the control port 155.2 of the second Load-holding counterbalance valve 150.2 leading channel 88.1 with Pressure medium of a corresponding pressure applied, whereby, depending on the currently in the flow channel 86th acting pressure, the load-holding counterbalance valve 150.2 more or less wide opens to a pressure medium flow of the second working space 45 via the channel 48 and over the second load-holding lowering brake valve 150.2 in the in FIG. 5 shown arrow direction in the return channel 87 to enable.

The control takes place in such a way that the here of the Load-holding lowering brake means 150.2 counter-pressure set depending on the movement of the piston 22 along the Cylinder 21 causing working pressure in the flow channel 86 is controlled, with increasing working pressure of the simultaneously acting back pressure decreases, and indeed preferably inversely proportional to the working pressure. In this way, it is always achieved during driving that the piston 22 with one of its current direction of movement opposing force is "clamped", which an uncontrolled advance of the piston 22 prevented becomes.

Should then the piston in a desired Stopping position are preferably both the Supply passage 86 and the return passage 87 pressure relieved. This closes both the return valves 156.1 and 156.2 as well - due to the then also in the Control channels 88.1 and 88.2 occurring pressure relief - the two load-holding lowering valves 150.1 and 150.2, so that in the working chambers 33 and 45 located Pressure medium can not escape from it. The piston 22 is so then between the ones on both its sides 44 and 46 clamped existing pressure columns and in its current Fixed stroke position.

A pressure relief on the channels 86 and 87 affects also in the switching channel 47 accordingly, so that the Locking bolt 40 by acting on them Spring forces of the springs 39 in the direction 28 of their Entriegelungsstellung in the shown in the figures Locking position 41 can be transferred. there This can be in the pressure medium spaces before the free Locking ends 57 of the locking pin 40 located Pressure medium via the channel 47 and the shuttle valve 160th here flow back into the flow channel 86.

Depending on, in which current rotary position the Spindle 35 and thus the locking recesses 38 at a current holding stroke position of the piston 22, then grab the locking pin 40 either in the Locking recesses 38 or lie on the to the head 31 of the cylinder 21 indicative end face of the the locking recesses 38 containing ring approach 65, which is between two immediately adjacent Locking recesses 38 are located. In such a, Any stop-stroke position of the piston 22, it is in Normally not relevant, whether the locking pin 40th or 140 engage in the locking recesses 38. Of course, something else applies in the case of one Leakage or damage in the pressure medium system. Then rotates the locking recesses 38 containing Approach slightly further until the locking bolts 40, 140 in the nearest locking recess 38th engage. In the illustrated and described embodiments However, it can only be a very small Hub of the piston 22 come, which is in the millimeter range and which is completely sufficient under safety aspects.

If the piston 22 and thus the piston rod 23 starting from the stroke position shown schematically in Figure 5 relative to the cylinder 21 in the opposite direction, d. H. be moved in the retraction 27, the Return channel 87 acted upon by pressure medium. Then it will be the locking member 171 of the shuttle valve 160 through the inflowing pressure medium in the right in Figure 5 shown Lock direction shifted so that then over the second inlet 165 in the second channel part 170 incoming Pressure medium via the discharge point 168 turn in the fluid channel 167 and from there into the switching channel 47th can flow, in which case the first channel portion 169 of the Fluid channel 159 is shut off by the locking means 171.

After unlocking the locking pin 140 or after these are transferred to their unlocked position, opens spring-loaded return flow 156.2, so that then Pressure medium can flow into the working chamber 45 to the To move piston 22 in the retraction 27. simultaneously depending on the current working pressure, now in the supply channel 87, the first load-holding lowering brake valve 150.1 via the with the control connection 155.1 fluid-connected control channel 88.2 controlled so that in the Working chamber 33, a back pressure is formed, the is less than the operating pressure in the working chamber 45, so that the movement of the piston 22 in the retraction direction 27 without an undesirable lead of the same he follows.

The operation of the lock cylinder will be described below 20 using the circuit shown in Figure 6 described in more detail:

As already mentioned above, the operation and Function of the load-holding lowering brake means 150.1, 150.2 same as explained by the example of the circuit according to FIG. 5, then that in this respect to the preceding parts of description can be referenced.

When the locking cylinder 20 via the flow channel 86th or the return passage 87 acted upon by pressure medium At the same time this will lead to an admission of the switching channel 47 with pressure medium. This way the fluid pressure medium through the switching channel 47, the gap 91 and the Durchströmspalt 71 in the locking recesses 38, so that through the training in it Oil pressure, the locking pin 140 against the spring force the respective spring 39 from that shown in FIG Locking position 41 in the not in the figures shown unlocked position can be pressed. It comes it also leads to a controlled leakage through the Throughflow channel 54 of each locking pin 40. If so For example, the flow channel 86 with a pressure medium flow can be applied pressure medium over the connected in parallel with the load-holding lowering brake valve 150.1 Rückströmsperre 156.1 in the channel 49 and from there in reach the first working chamber 33 and at the same time over the first check valve 84 of the Rückströmsperrmittels 161st get into the switching channel 47. The pressure medium flows so then via the first inlet 164 of the Rückströmsperrmittels 161 in the first channel part 169 of the fluid channel 159 and there via the estuary 168 in the branched off Fluid channel 167 and again from there into the switching channel 47th In this case, the second check valve 85 of the Rückströmsperrmittels 161 closed, d. H. whose locking member 172.2 locks the second channel part 170.

As soon as the locking bolts 140.1 and 140.2 at further Oil supply can be transferred to its unlocked position, can the piston 22 due to a simultaneous Apply pressure to the bottom of the cylinder 53 pointing side 46 in the extension direction 28 move. As soon as the pressure medium flow in the flow channel 86 is preferred drops to zero, both close Rückströmsperren 156.1 and 156.2 and both load-holding lowering brake valves 150.1 and 150.2. Almost at the same time the locking bolts 140 by the springs 39 in Extension direction 28 shifted so that it depends on the current position of the locking recesses 38 there can engage, so that in the locking position 41 the spindle 35 and thus the piston 22 both hydraulically as well as mechanically locked.

Is based on the above reached stroke position the piston 22 moves this back in the retraction direction be, the return passage 87 with pressure medium be charged, d. H. the pressure medium can be there be supplied. The pressure medium can then over the Check valve 156.2 enter the channel 48 and from out there in the working chamber 45, so that the piston rod side end facing side 44 of the Piston 42 can be acted upon with pressure medium. At the same time arrives from the return passage 87 a branched pressure medium flow through the second check valve 85 of the Rückströmsperrmittels 161 turn in the Switching channel 47, while the first check valve 84th is closed. This leads in the same way as already explained above, that the locking bolts 140 automatically, d. H. without additional switching, in their unlocked position to be transferred. Then moved the piston 22 and thus the piston rod 23 in Einfahrrichtung 27, wherein as well as in the above Explained in connection with the circuit according to FIG. 5, in FIG the working chamber 33 acts a back pressure, which is smaller as the working pressure in the working chamber 45, so that again no uncontrolled advance of the piston 22 in the retraction 27 may occur.

It is therefore a characteristic process feature according to the shown in Figure 6 that the pressure means for Purposes of retraction and / or for the purpose of extension the piston 22 at least one side 44 or 46 of the Piston 22 and at the same time the locking pin 40th is supplied, wherein the locking pin 40 counter the spring force of the spring 39 from the locking position 41 is transferred to the unlocked position, so that then the spindle 35 in a rotational direction 51st or in an opposite direction of rotation 52 can rotate with the result that the piston 22 corresponding to the Direction of rotation 51 or 52 in the extension direction 28 or in Einfahrrichtung 27 is moved.

The pressure fluid flowing back through the channel 55 can, depending after which of the channels 86 or 87 pressurizes is, either via the check valve 82 or via the check valve 83 in the channel 86 or in the Channel 87 are returned.

Claims (12)

Locking cylinder (20) with a cylinder (21) and a piston (22), which by means of a two sides of the piston (22) in a first working chamber (33) and in a second working chamber (45) can be fed fluid pressure medium parallel to the longitudinal axis (29 ) of the cylinder (21) is movable, and which is provided with a piston thread (34) which, forming a non - self - locking thread (37) with a spindle thread (36) of a spindle (35) is engaged, which is parallel to the The longitudinal axis (29) of the cylinder (21) arranged rotation axis (43) is rotatable and at least one outwardly open locking recess (38) into which at least one acted upon by spring force of a spring locking body (42, 142) can engage, against a Rotation about the axis of rotation (43) of the spindle (35) secured and fixedly connected to the cylinder (21), but is mounted relative to this movable, and by means of the spring force of the spring (39) in a Verriegelun position (41), in which it engages in the locking recess (38) of the spindle (35), so that then rotation of the spindle (35) about its axis of rotation (43) is blocked, and wherein the locking body (42, 142 ) by means of a fluid working means against the spring force of the spring (35) from the locking position (41) into an unlocking position is transferred, in which the spindle (35) about its axis of rotation (43) is rotatable to a movement of the piston (22) along the cylinder (21) to allow, and wherein control means for controlling the movement of the piston (22) and the locking body (42, 142) and the locking body (42, 142) are provided,
characterized in that at least a first load-holding Senkbrems means (150.1) with the first working chamber (33) is fluidly connected and that at least a second load-holding Senkbrems means (150.2) with the second working chamber (45) is fluidly connected, wherein the at least two load-holding lowering brake means (150.1, 150.2) cause, when the piston (22) is acted upon on its first side (46) with the pressure medium in the first working chamber (33) to produce a working pressure which is a displacement of the piston ( 22) in a first direction (28), at the same time in the second working chamber (45) on the second side (44) of the piston (22) by the located in the second working chamber (45) pressure means acting back pressure acts, which is smaller as the working pressure in the first working chamber (33), so that an uncontrolled advance of the piston (22) in the first direction (28) is avoided, and vice versa upon application of the piston (22) on its second side (44) with the in the second working chamber (45) located pressure means to form a working pressure, which causes a displacement of the piston (22) in a second direction (27) opposite to the first direction (28) in that in the first working chamber (33) on the first side (46) of the piston (22) a counterpressure exerted by the pressure medium in the first working chamber (33) acts, which is smaller than the working pressure in the second working chamber (45). such that uncontrolled advance of the piston (22) in the second direction (27) is avoided, and wherein the load-holding lowering brake means (150.1, 150.2) at a desired pressure relief for the purpose of holding the piston (22) in a desired Lift position a backflow of the pressure medium from both working chambers (33, 45) lock, so that the piston (22) is held by the pressure in the working chambers (35, 45) in the desired stroke position , Locking cylinder according to claim 1, characterized in that the back pressure controlled by the load holding lowering brake means (150.1, 150.2) is controlled as a function of the respective working pressure causing movement of the piston (22) along the cylinder (21). Locking cylinder according to claim 2, characterized in that the back pressure controlled by the load-holding lowering brake means (150.1, 150.2) is controlled as a function of the respective working pressure causing movement of the piston (22) along the cylinder (21), so that increasing working pressure of the simultaneously acting back pressure decreases. Locking cylinder according to claim 3, characterized in that the back pressure is controlled inversely proportional to the working pressure. Locking cylinder according to one of claims 1 to 4, characterized in that the load-holding Senkbrems means (150.1, 150.2) each have a first inlet for the pressure medium (153.1, 153.2), an outlet for the pressure medium (154.1, 154.2) and a control terminal (155.1, 155.2) for the pressure medium, wherein the inlet (153.1) of the first load-holding Senkbrems means (150.1) with the first working chamber (33) is fluidly connected and the inlet (153.2) of the second load-holding Senkbrems means (150.2 ) is fluidly connected to the second working chamber (45), and wherein the outlet (157.1) of the first load-holding lowering brake means (150.1) is in fluid communication with the control port (155.2) of the second load-holding lowering brake means (150.2) and the outlet (15) 154.1) of the second load-holding lowering brake means (150.2) is fluid-connected to the control port (155.1) of the first load-holding lowering brake means (150.1), and wherein with the inlet (153.1, 153.2) and the outlet (154.1, 154.2) of jew In each case a Rückströmsperrmittel (156.1, 156.2) is fluidly connected, each having a flow of the pressure medium from the outlet (154.1, 154.2) to the inlet (153.1, 153.2) of the respective load-holding lowering brake Means (150.1, 150.2), but which blocks an opposite direction respectively, and that optionally the outlet (154.1) of the first load-holding lowering brake means (150.1) and thus the control terminal (155.2) of the second load-holding lowering brake means ( 150.2) or the outlet (154.2) of the second load-holding lowering brake means (150.2) and thus the control port (155.1) of the first load-holding lowering brake means (150.1) are acted upon with pressure medium to a movement of the piston (22) in the First direction (28) or in the second direction (27) due to the respective working pressure and with simultaneous formation of the respective back pressure, via the second load-holding Senkbrems means (150.2) or via the first Lasth Old lowering brake means (150.1) depending on the pressure acting on the respective control port (155.1, 155.2) pressure to effect. Locking cylinder according to claim 5, characterized in that optionally the outlet (154.1) of the first load-holding lowering brake means (150.1) or the outlet (154.2) of the second load-holding lowering brake means (150.2) in fluid communication with the locking body (42, 142 ) or the locking bodies (42, 142) can be brought, so that upon exposure of the outlet (154.1) of the first load-holding lowering brake means (150.1) or the outlet (154.2) of the second load-holding lowering brake means (150.2) Pressure means, this the locking body (42, 142) and the locking bodies (42, 142) is supplied to transfer this or these in his or her unlocked position. Locking cylinder according to claim 5 or 6, characterized in that between the outlet (154.1) of the first load-holding lowering brake means (150.1) and the outlet (154.2) of the second load-holding lowering brake means (150.2) at least one Rückströmsperrmittel (160, 161 ) is arranged, which upon application of pressure to the outlet (154.1) of the first load-holding lowering brake means (150.1) prevents pressure medium flow to the outlet (154.2) of the second load-holding lowering brake means (150.2) and vice versa upon application the outlet (154.2) of the second load-holding lowering brake means (150.2) prevents a pressure fluid flow to the outlet (154.1) of the first load-holding lowering brake means (150.1) with pressure medium, and in both cases a supply of the pressure medium to the locking body or . The locking bodies (42, 142) permits, so that this or this is transferred to its unlocking position or be. Locking cylinder according to claim 7, characterized in that the non-return valve means (160) has a first inlet (164) for the pressure medium, a second inlet (165) for the pressure medium and an outlet (166) for the pressure medium, wherein the first inlet (164 ) of the return flow blocking means (160) is fluidly connected to the outlet (154.1) of the first load-holding lowering brake means (150.1), and wherein the second inlet (165) of the return flow blocking means (160) is connected to the outlet (154.2) of the second load-holding lowering brake Is fluidly connected by (150.2), and wherein the first inlet (164) of the Rückströmsperrmittels (160) and the second inlet (165) of the Rückströmsperrmittels (160) via a fluid channel (167) are interconnected, in which a with the outlet (166 ) of the Rückströmsperrmittels (160) connected fluid channel (167) at an orifice (168) opens, so that from the orifice (168) a first channel part (169) of the fluid channel (167) and a second Duct member (170) of the fluid channel (167) branches off, and wherein a locking member (171) for shutting off the first channel part (169) or the second channel part (170) is provided, and wherein in the shut-off state of the second channel part (170) of the first inlet (164) of the backflow blocking means (160), the first channel portion (169) and the outlet (166) of the backflow blocking means (160) are fluidly connected such that pressurized fluid flow from both the first inlet (164) of the backflow blocking means (160) to the outlet (16) 166) of the non-return valve means (160) and from the outlet (166) of the non-return means (160) to the first inlet (164) of the non-return means (160), and conversely in the shut-off condition of the first channel part (169) the second inlet (166) 165) of the backflow blocking means (160), the second channel portion (170) and the outlet (166) of the backflow blocking means (160) are fluidly connected such that pressurized fluid flow from both the second inlet (165) of the non-return valve means (160) to the outlet (166) of the non-return means (160) and from the outlet (166) of the non-return means (160) to the second inlet (165) of the non-return means (160). Locking cylinder according to claim 7, characterized in that the non-return valve means (161) has a first inlet (164) for the pressure medium, a second inlet (165) for the pressure medium and an outlet (166) for the pressure medium, wherein the first inlet (164 ) of the Rückströmsperrmittels (161) is fluidly connected to the outlet (154.1) of the first load-holding lowering brake means (150.1), and wherein the second inlet (165) of the Rückströmsperrmittels (161) with the outlet (154.2) of the second load-holding Senkbrems- Is fluidly connected by (150.2), and wherein the first inlet (164) of the Rückströmsperrmittels (161) and the second inlet (165) of the Rückströmsperrmittels (161) via a fluid channel (167) are connected to one another with the outlet (166 ) of the Rückströmsperrmittels (161) connected fluid channel (167) opens at an orifice (168), so that from the orifice (168) a first channel part (169) of the fluid channel (167) and a second A first locking member (172.1) for shutting off the first channel part (169) and a second locking member (172.2) for shutting off the second channel part (170) is provided, the first channel part (17). 169) and the second channel portion (170) shut off fluid flow from the outlet (166) of the backflow blocking means (161) to the first inlet (164) of the backflow blocking means (161) and the second inlet (165) of the backflow blocking means (161) and the one pressure medium flow from the first inlet (164) of the backflow blocking means (161) to the outlet (166) of the backflow blocking means (161) and from the second inlet (165) of the backflow blocking means (161) to the outlet (166) of the backflow blocking means (161). Locking cylinder according to claim 5, characterized in that the working means or the pressure means to the locking body (142) or the locking bodies (142) is supplied to transfer this or these in his or her unlocking position and that at the same time the pressure medium optionally the first Working chamber (33) or the second working chamber (45) is supplied to cause a movement of the piston (22) in the first direction (28) or in the second direction (27). Locking cylinder according to claim 5, characterized in that the working means or the pressure means first the locking body (42) and the locking bodies (42) is supplied to transfer this or these in his or her unlocking position and then that the pressure medium optionally the first working chamber (33) or the second working chamber (45) is supplied to cause a movement of the piston (22) in the first direction (28) or in the second direction (27). Locking cylinder according to claim 11, characterized in that the respective Rückströmsperrmittel (156.1, 156.2) a locking member (173.1, 173.2) for preventing a flow of pressure medium from the inlet (153.1, 153.2) to the outlet (154.1, 154.2) of the respective load-holding Senkbrems- Means (150.1, 150.2) acted upon by spring forces of a spring (174.1, 174.2), such that opening of the non-return valve means (156.1, 156.2) and consequently a flow of pressure medium from the outlet (154.1, 154.2) to the inlet (153.1, 153.2) of the respective load-holding lowering brake means (150.1, 150.2) is made possible only when a limit pressure of the pressure medium is exceeded, the value of which depends on a spring characteristic of the respective spring (174.1, 174.2).

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