DE10356596B3 - Locking cylinder for hydraulic system has load-holding descent brake devices connected to two working chambers - 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 The invention relates to a locking cylinder with a cylinder and a piston parallel with the aid of a fluid pressure medium to the longitudinal axis of the cylinder is movable, and provided with a piston thread is, with the formation of a non-self-locking thread with a spindle thread of a spindle is engaged, which is a parallel to the longitudinal axis The axis of rotation of the cylinder is rotatable and the at least one outwards has open locking recess, in the at least one means Spring force of a spring acted upon locking body can intervene, the secured against rotation about the axis of rotation of the spindle and is mounted movably relative to the cylinder and by means of Spring force of the spring can be converted into a locking position, in which it engages in the locking recess of the spindle, so that then blocks rotation of the spindle about its axis of rotation is, and wherein the locking body using a fluid Working means against the spring force of the spring from the locking position can be converted into an unlocked position, in which the spindle is rotatable about its axis of rotation to a movement of the piston along to allow the cylinder.

Such a locking cylinder is out of the JP 083 034 10 A known. There is provided as a locking body a large-volume locking piston, through the central passage opening, a shaft of a ball screw extends and which is integrally connected to a plurality of concentric with the spindle and arranged upstanding along the spindle teeth. In the locking position, the teeth of the locking piston are in engagement with opposite teeth of a gear which is rotatably connected to this concentric receiving spindle. As a result, a kind of toothed coupling is formed. The locking piston has on its side facing away from the teeth side a hollow portion with an internal toothing, and the tooth flanks of the teeth of the internal toothing extend parallel to the axis of rotation of the spindle. The internal gear is engaged with a matching external toothing of a pinion, which is fixedly connected to a cover plate of the cylinder. In this way, the locking piston is displaceable parallel to the axis of rotation of the ball screw, but stored blocked against rotation about the spindle axis.

At the outer periphery the locking piston is provided with a circumferential seal, the one pressurized fluid space to the end cover of the cylinder seals.

These Construction of a locking unit is complicated and stressed comparatively much space. For unlocking or locking the design huge and compact and therefore weighty locking piston are comparatively size personnel needed and / or it must be comparatively long locking or locking times are accepted, which also means a corresponding security risk. The locking piston must be on its outer circumference be sealed with a circumferential seal, what when moving the locking piston for the purpose of locking or unlocking to appropriate frictional forces leads, whereby the efficiency of this locking cylinder limited is.

The Ball screw is so on the cylinder via a ball bearing and a stored at the free end of the spindle shaft slide bearing clamped that movement of the spindle in the longitudinal direction of the cylinder is not possible is while a rotation of the spindle about its longitudinal axis is possible. This is supported the free end of the spindle shaft sliding on an inner surface of the End cap off the cylinder and the ball bearing is using one on an external thread the ball screw screwed nut against a transverse to Cylinder running paragraph fixed.

These Construction is limited to applications where only comparatively small loads can be raised. For larger loads can However, it is up to a wear come to the feeding of the plain bearing. It can contribute to education and detachment of metal shavings or particles come, which the function of the locking unit impair can, up to a blockade of the locking piston. This means an unacceptable Security risk.

The Control of the locking piston having locking unit and the control of the movement of the piston take place in this construction via mechanical coupled directional valves such that when lifting or at lowering the load to undesirably advance the piston can come. This means a piston movement that is difficult to control. Especially at elevated To press or piston speeds, it may cause cavitation at the Piston seal and the piston rod come, which is a security risk means and what limits the life accordingly.

It is therefore an object of the invention, a locking cylinder to create, which allows in particular a higher reliability.

This object is achieved according to a first solution idea or according to a particularly preferred embodiment of the above-mentioned locking cylinder by the following features:
The lock cylinder comprises a cylinder and a piston which is movable parallel to the longitudinal axis of the cylinder by means of a fluid pressure means which can be supplied to both sides of the piston and which is provided with a piston thread engaging a spindle thread of a spindle to form a non-self-locking thread which is rotatable about a rotation axis arranged parallel to the longitudinal axis of the cylinder and which has at least one outwardly open locking recess into which at least one locking element acted upon by spring force of a spring can engage, which is secured against rotation about the axis of rotation of the spindle and parallel to the axis of rotation the spindle is axially displaceably mounted on a head of the cylinder, and by means of the spring force of the spring in a locking position can be transferred, in which it into the locking recess of the spindle to form a positive and bidirectional Locking the spindle engages, so that then rotation of the spindle is blocked about its axis of rotation in opposite directions of rotation and wherein the locking body by means of a fluid working means against the spring force of the spring from the locking position can be converted into an unlocking position, in which the spindle about its axis of rotation is to allow movement of the piston along the cylinder and wherein a plurality of locking bodies are designed as a separately movable locking bolt.

Thereby that the locking body are designed as a separately movable locking bolt can jamming or tilting during locking can be avoided. In contrast to the prior art, such are known Locking bolt easy and inexpensive to produce and stress only a minimal installation and Control room, so that the gained space beneficial to others Elements and / or tasks can be used or a total smaller and lighter locking cylinder can be provided can.

conditioned through the aforementioned measures Only comparatively small locking and unlocking forces are needed. Thereby can the locking cylinder in the area of the locking unit in total space-saving or lighter running. Also can be thereby achieve significantly reduced locking and unlocking times. After all when using the separately movable locking bolt no circumferential seals between them and the cylinder wall needed.

On this way, therefore, a locking cylinder can be provided, the with simple and space-saving locking construction higher operational safety allows and having a better efficiency.

In Advantageous development can be provided that the locking bolt independently of each other are arranged movable, ie in particular without mechanical positive coupling between the locking bolts. According to a further embodiment can be provided that only two separate locking bolts be used. By doing so leaves to further reduce the risk of jamming or jamming.

According to one again another embodiment can be provided that the locking bolts each in a to the side of the locking recesses open towards Lagerausnehmung of the head of the cylinder are stored with little play.

From it may be particularly advantageous if it is the locking bolt to cylinder pin is, preferably a circular cylindrical outer contour exhibit. It may therefore be particularly advantageous if the locking bolt each at their free locking ends a conical outer contour and / or if the cylinder bolts each in one a cylindrical inner contour having bearing recess with low Game are stored.

According to one another embodiment can be provided that the locking bolts each one to their, having the end associated with the respective spring outwardly open recess, in which each designed as a compression spring spring with a spring section is recorded and there with one of their ends at each one palm the respective locking bolt is supported, with their other End is supported on the head of the cylinder.

According to one another embodiment can be provided that the locking bolts each have a circumferential sealing surface have, in the unlocking of the respective locking bolt points, and in the unlocked position of the respective locking bolt and then under the working means in the unlocked position exerted compressive forces at a circumferential mating surface of the head of the cylinder sealingly applied.

According to a further embodiment, it may be provided that the sealing surface at the same time a stop surface for limiting a Entriegelungshubes the respective locking bolt formed.

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

According to one another embodiment can be provided that the sealing surface on an annular end edge of the locking bolt is arranged at its end associated with the spring.

According to one another embodiment can be provided that the locking bolt closed cross-section are designed so that when sealing at the respective sealing surface adjoining sealing surface the respective locking bolt leakage of the working fluid is prevented along the respective locking bolt.

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

According to one further advantageous embodiment can be provided that the respective passageway at 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, attack on the fluid working medium can to the respective locking bolt in its unlocked position to convict.

According to one further advantageous embodiment can be provided that the respective passage in the respective locking bolt to form a support and Investment level for each formed as a compression spring spring laterally expanded.

According to a second solution thought or according to a particularly preferred embodiment of the above-mentioned locking cylinder, the invention task is also solved by a locking cylinder having the following features:
The locking cylinder comprises a cylinder and a piston which is movable by means of a fluid pressure medium parallel to the longitudinal axis of the cylinder and which is provided with a piston thread which engages to form a non-self-locking thread with a spindle thread of a spindle which is parallel to the Rotary axis arranged along the longitudinal axis of the cylinder is rotatable and which has at least one outwardly open locking recess into which at least one acted upon by spring force of a spring locking body which is secured against rotation about the axis of rotation of the spindle and parallel to the axis of rotation of the spindle axially displaceable on a Head of the cylinder is mounted, and which is converted by means of the spring force of the spring in a locking position in which it engages in the locking recesses of the spindle, so that then a rotation of the spindle is blocked about its axis of rotation and wherein the Ver locking body by means of a fluid working means against the spring force of the spring from the locking position into an unlocking position is transferred, in which the spindle is rotatable about its axis of rotation to allow movement of the piston along the cylinder, wherein the spindle is mounted on at least two thrust bearings, of which a first thrust bearing preferably designed as a rolling bearing is intended to receive axial forces acting on the spindle in a first direction, and wherein a second thrust bearing is intended to receive axial forces acting on the spindle in a second direction opposite to the first direction, and wherein the spindle is mounted so as to be axially movable relative to the cylinder and is fixedly connected to a support body different from the second thrust bearing, which is intended to absorb axial forces acting on the spindle in the second direction, and in that the second thrust bearing is moved in the direction de Is designed for the longitudinal axis of the cylinder movable rolling bearing, which is acted upon by spring forces acting in the first direction of a spring, so that a resilient mounting of the spindle is effected.

By the aforementioned measures can even big ones Loads are moved and / or large piston speeds be realized without causing any significant wear in the area the camp is coming, and it's over ensures long-term safe operation of such locking cylinder.

On this way, therefore, a locking cylinder can be provided, the space-saving design in the spindle storage and in the area of the locking unit enables a higher level of operational safety.

According to an advantageous embodiment, it can be provided that the support body has at its free end a support surface which is supported on an opposite support surface of the head of the cylinder when the support body receives in the second direction acting on the spindle axial forces and preferably transferred to the cylinder. Such an advantageous support will occur in particular in an overload or damage case.

According to one further advantageous embodiment it can be provided that the support body in an admission the spindle with a certain limit axial force below and operating axial force acting on the spindle in the second direction from the support surface of the head lifted off the cylinder, wherein in the off-state, the spindle is resiliently mounted on the second thrust bearing.

According to one further advantageous embodiment can be provided that the support body in an admission the spindle in the second direction with an overload axial force equal to big or is larger as the limit axial force on the support surface of the head of the cylinder which supports the overload axial forces on the cylinder is transferred or be compensated there.

According to one 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 with the operating axial force is applied, the support body, the second thrust bearing and the spindle opposite to that of the spring on the second Thrust bearing exercised spring forces be axially displaced in the second direction until the support body to the support surface of the Head of the cylinder rests, so that in the second direction Overload axial forces acting on the spindle the support body on the Cylinder transferred or be compensated there.

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

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

According to one further advantageous embodiment it can be provided that the second thrust bearing is received on the support body is.

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

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

According to one further advantageous embodiment can be provided that the first thrust bearing a first ring bearing formed with a first bearing diameter and that the second thrust bearing forming a second ring bearing with a second bearing diameter, which is smaller than the first bearing diameter of the first ring bearing.

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

According to one further advantageous embodiment can be provided that the spring to form a cup spring package designed with several disc springs.

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

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

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

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

According to one further advantageous embodiment can be provided that several locking body provided are, as preferably elongated, in particular separately movable Locking bolts are designed.

According to a further solution idea or according to a further particularly preferred embodiment of the above-mentioned locking cylinder, the invention task is also solved by a locking cylinder having the following features:
The locking cylinder comprises a cylinder and a piston which is movable parallel to the longitudinal axis of the cylinder by means of a fluid pressure medium which can be supplied to a first working chamber and into a second working chamber and which is provided with a piston thread forming a non-self-locking Thread with a spindle thread of a spindle is engaged, which is rotatable about a parallel to the longitudinal axis of the cylinder axis of rotation and which has at least one outwardly open locking recess into which at least one acted upon by spring force of a spring locking body can engage, against rotation about secured the axis of rotation of the spindle and fixedly connected to the cylinder, but is mounted relative to this movable, and by means of the spring force of the spring in a locking position can be transferred, in which it engages in the locking recess of the spindle, d Ass then a rotation of the spindle is blocked about its axis of rotation, and wherein the locking body by means of a fluid working means against the spring force of the spring from the locking position can be converted into an unlocked position in which the spindle is rotatable about its axis of rotation to a movement of the piston along and wherein control means for controlling the movement of the piston and the locking body or the locking body are provided, and wherein at least a first load-holding Senkbrems means fluidly connected to the first working chamber and that at least a second load-holding Senkbrems-means is fluidly connected to the second working chamber, wherein the at least two load-holding Senkbrems means cause upon application of the piston on its first side with the pressure medium in the first working chamber to form a working pressure, a displacement of the piston in a he causes a simultaneously acting in the second working chamber on the second side of the piston through the located in the second working chamber pressure means back pressure which is smaller than the working pressure in the first working chamber, so that an uncontrolled advance of the piston in the first direction is avoided, and that, conversely, upon application of the piston on its second side with the pressure medium in the second working chamber to form a working pressure, which causes a displacement of the piston in a second direction opposite to the first direction, simultaneously in the first working chamber at the first side of the piston acting through the located in the first working chamber pressure medium back pressure 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 wherein the load-holding Senkbrems means at a desired pressure relief for the purpose of holding the piston in a desired stroke position lock a return flow of the pressure medium from both working chambers, so that the piston is held by the pressure medium in the working chambers in the desired stroke position.

Thereby let yourself the piston in its movement along of the cylinder between the pressures acting in the working chambers quasi "clamp", so that an uncontrolled Leading or uncontrolled movements of the piston avoided with certainty can be. Furthermore, can thereby both high and highest Piston speeds are driven, without causing cavitation effects in the area of the piston seal and / or the piston rod comes as also small to smallest piston speeds, d. H. it can can advantageously be driven in "creep".

On this way, therefore, a locking cylinder can be provided, with extended application and application possibilities as well as a longer service life a higher one Operational safety allows.

According to one preferred embodiment can be provided that of the load-holding lowering brake means controlled backpressure dependent from the respective, causing a movement of the piston along the cylinder Working pressure is controlled.

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

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

According to a preferred embodiment, it may be provided that the load-holding lowering brake means each have a first inlet for the pressure medium, an outlet for the pressure medium and a control port for the pressure medium, wherein the inlet of the first load-holding Senkbrems means with the first working chamber fluidly connected and the inlet of the second load-holding lowering brake fluid is fluidly connected to the second working chamber, and wherein the outlet of the first load-holding Senkbrems agent is fluidly connected to the control port of the second load-holding lowering means and the outlet of the second load hold-lowering brake means is fluidly connected to the control port of the first load-holding lowering brake means, and wherein each of the inlet and the outlet of the respective load-holding lowering brake fluid communication is a Rückströmsperrmittel, each having a flow of the pressure medium from the outlet to the Inlet of the respective load-holding lowering brake means permits, but which blocks in an opposite direction respectively, 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 Senkbrems- By means of and thus the control terminal of the first load-holding lowering brake means are acted upon with pressure medium to a movement of the piston in the first direction or in the second direction due to the respective working pressure and with simultaneous formation of the respective back pressure, via the second load-holding Senkbrems Means or over the first load-holding S Enkbrems means depending on the pressure acting on the respective control port pressure to effect.

According to one preferred embodiment can be provided that optionally the outlet of the first load-holding lowering brake means or the outlet of the second load-holding countershaft means in fluid communication with the locking body or the locking bodies is bringable, so that when an admission of the outlet of first load-holding lowering brake means or the outlet of the second Load-holding lowering brake means with pressure medium, this the locking body or the locking bodies supplied is to this or this in his or her unlocking position to convict.

According to one preferred embodiment it can be provided 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, which when an admission of the outlet of the first Load-holding lowering brake means with pressure medium a pressure medium flow to Outlet of the second load-holding lowering brake means prevented and vice versa when an admission of the outlet of second load-holding lowering brake means with pressure medium, a pressure medium flow to the outlet of the first Load-holding counter-brake means prevented, and in both cases a Supply of the pressure medium to the locking body or the locking bodies permits, so that this or this is transferred to its unlocking position or become.

According to one preferred embodiment can be provided that the Rückströmsperrmittel a first inlet for the pressure medium, a second inlet for the pressure medium and an outlet for the Pressure means, wherein the first inlet of the Rückströmsperrmittels fluidly connected to the outlet of the first load-holding countershaft means and wherein the second inlet of the Rückströmsperrmittels with the outlet the second load-holding lowering brake means fluid-connected, and wherein the first inlet of the Rückströmsperrmittels and the second inlet of the Rückströmsperrmittels via a fluid passage are connected to one another with the outlet of the Rückströmsperrmittels Connected fluid channel opens at an orifice, so that from the confluence point 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 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 the Rückströmsperrmittels, the first channel part and the outlet of the backflow blocking means are fluid-connected, so that a pressure medium flow both from the first inlet of the non-return valve to the outlet the Rückströmsperrmittels as well as from the outlet of the Rückströmsperrmittels to the first inlet of the Rückströmsperrmittels is admitted, and vice versa in the locked state of the first channel part of the second inlet of the Rückströmsperrmittels, the second channel part and the outlet of the non-return valve fluid-connected, so that a flow of pressure medium from both of the second Inlet of Rückströmsperrmittels to the outlet of the Rückströmsperrmittels as well as from the outlet of the Rückströmsperrmittels to the second inlet of the Rückströmsperrmittels is allowed.

According to a preferred embodiment, it may be provided that the non-return valve comprises a first inlet for the pressure medium, a second inlet for the pressure medium and an outlet for the pressure medium, wherein the first inlet of the Rückströmsperrmittels is fluidly connected to the outlet of the first load-holding lowering brake means and wherein the second inlet of the non-return valve means is fluidly connected to the outlet of the second load-holding lowering brake means, and wherein the first inlet of the Rückströmsperrmittels and the second inlet of the Rückströmsperrmittels are interconnected via a fluid passage in which a connected to the outlet of the Rückströmsperrmittels Fluid channel opens at an orifice point, so that branches off from the estuarine a first channel part of the fluid channel and a second channel part of the fluid channel, and wherein a first locking member for shutting off the first channel part and a second locking member for shutting d It is provided to the second channel part, 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 allow the pressure fluid flow from the first inlet of the Rückströmsperrmittels to the outlet of the Rückströmsperrmittels and the second inlet of the Rückströmsperrmittels to the outlet of the Rückströmsperrmittels.

According to one preferred embodiment can be provided that the working fluid or the pressure medium the locking body or the locking bodies supplied is to convict this or this in his or her unlocking position and that at the same time the pressure medium optionally 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 cause.

According to one preferred embodiment can be provided that the working fluid or the pressure medium first the locking body or the locking bodies supplied is to this or this in his or her unlocking position to convict and that then the pressure medium either the first working chamber or supplied to the second working chamber is to move the piston in the first direction or in to effect the second direction.

According to one preferred embodiment can be provided that the respective Rückströmsperrmittel a locking member for preventing a flow of pressurized fluid from the inlet to the Outlet of the respective load-holding lowering brake means, which by spring forces a Spring is applied, so that opening the Rückströmsperrmittels and consequently a pressure medium flow from the outlet to the inlet of the respective load-holding lowering brake means only from above a limit pressure of the pressure medium is allowed, the value of a spring characteristic of the respective spring depends.

It It is understood that the above measures are within the scope of executability in a locking cylinder of the type mentioned also can be combined as desired, to a locking cylinder with accordingly combined To be able to provide advantages.

Further Aspects, features and advantages of the invention can the in the following part of the description, in which two preferred embodiments the invention are described in detail with reference to the figures:

It demonstrate:

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

2 an enlarged section of the cross section according to 1 in the area of the locking bolt shown on the right;

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

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

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

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

The in 1 shown locking cylinder 20 includes a cylinder 21 and a piston slidably mounted therein longitudinally 22 , The piston 22 is opposite the cylinder inner wall by a ring seal 68 sealed and is on his 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 medium-assisted movement of the piston 22 in a direction of retraction, also referred to as a second direction or unlocking direction 27 or in a direction of extension also called the first direction 28 to enable.

The piston 22 is fixed with a piston rod 23 connected, extending from its front 44 coaxial with the cylinder axis 29 extends. The cylinder 20 is at its free end 67 the spindle 35 assigned side by a the piston rod 23 receiving lid 30 completed. On the other side is the cylinder 21 firmly with a stepped approach 66 connected. This is in turn by a cylinder bottom 53 forming lid or head 31 completed.

The piston 22 forms an approach 32 , which rotates with the piston rod 23 connected is. The piston 22 is designed as a tubular hollow body and has a female thread, also referred to as a piston thread 34 on. This is engaged with an external thread, also referred to as a spindle thread 36 a spindle 35 on which the piston 22 is guided. The internal thread 34 of the piston 22 and the external thread 36 the spindle 35 are preferably designed as eight-speed trapezoidal coarse thread, which together form a non-self-locking thread 37 form.

For fastening the locking cylinder 20 has the piston rod 23 at its free end a here designed with an eyelet fastener 25 on, and a corre sponding designed fastener 26 is opposite to the head 31 of the cylinder 21 attached.

The pressure medium is through the channels 48 and 49 on both sides 44 and 46 of the piston 22 in a first working chamber 45 and into a second working chamber 33 fed to a movement of the piston 22 along the cylinder 21 in retraction direction 27 or in the extension direction 28 to reach. Here is the first working chamber 45 opposite the second working chamber 33 over the ring seal 68 of the piston 22 sealed.

In the area of the free end 67 the spindle 35 pointing away end 77 the spindle 35 This is rotatable with a flange-shaped approach 65 connected. This has in the region of its cylinder bottom end a transversely or perpendicular to the axis of rotation 43 the spindle 35 extending, here annular wall part 79 on. This one is on the free end 67 the spindle 35 pointing side through a first thrust bearing 120 , here in the form of a first ring bearing 127 , here as a needle bearing 138 is formed at a supporting and conditioning stage of the cylinder approach 66 stored. This as a rolling bearing 137 designed ring bearings 127 serves to, in the extension direction 28 on the spindle 35 to absorb acting axial forces. To the one in the retraction direction 27 opposite to the extension direction 28 on the spindle 35 To be able to absorb acting axial forces, two measures are taken:
To accommodate the during normal operation of the locking cylinder 20 in the first direction 28 on the spindle 35 acting axial thrust, is a second thrust bearing 121 in the form of a second ring bearing 130 provided at the head end 77 the spindle 35 is arranged. This thrust bearing 121 is also as a rolling bearing 122 in the form of a needle bearing 123 designed. It is on a coaxial axis of rotation 43 the spindle 35 firmly with the spindle 35 connected support body 124 in the form of a cylinder bolt 125 taken in the direction of the cylinder bottom or head 31 of the cylinder 21 extends and coaxial with the axis of rotation 43 spindle 35 is arranged.

To the needle bearing 123 closes in the retraction direction 27 a plate spring package 135 on, consisting of several disc springs 134 . 136 consists. In the embodiment shown are five disc springs 134 and five disc springs 136 intended. Here are the disc springs 134 and the cup springs 136 each alternately successively preferably arranged such that in each case the spring travel of each plate spring 134 . 136 for a resilient mounting of the spindle 35 is available. The disc springs 134 . 136 are chosen in terms of their spring characteristics and arrangement such that in regular driving when the piston 22 in retraction direction 27 which is moved by the non-self-locking thread 37 and the spindle 35 transmitted dynamic resulting forces are absorbed, ie compensated, so that the supporting body 124 always from the head 31 the cylinder bottom of the cylinder 21 is lifted off.

However, if the piston 22 in the opposite direction, ie in the extension direction 28 is extended, it acts on the spindle 35 a resulting axial force in the extension direction 28 , so that even with this piston movement of the support body 124 always from the head 31 is lifted off.

Nothing else applies in the case of holding the piston 22 in a desired stroke position. Because then, as will be explained in more detail below, the piston 22 of pressure medium, located in the two working chambers 33 and 45 as well as with these fluid-connected channels 49 and 48 is held "clamped" so that even under allowable high static loads coming from the locking cylinder 20 to be held or moved, the support body 124 always from the head 31 of the cylinder 21 is lifted off. In this case, so that is using the locking cylinder 20 to be held static load and in this regard on the spindle 35 transmitted axial forces substantially over the piston 22 and the pressure medium acting on it and received via the adjacent cylinder walls.

However, if a claim occurs, so z. B. leakage in the area or a fraction of a pressure medium line occurs, can in the retraction 27 acting overload axial forces occur from the small needle bearing 123 can not be absorbed without destruction. Because this second needle bearing 123 has a relation to the carrying capacity or the supporting diameter of the first needle bearing 138 smaller carrying capacity or smaller load-bearing diameter to meet the requirements for the most space-saving design of the locking cylinder 20 in the locking and storage area. The wear the used disc springs 134 and 136 Invoice, so that when exposed to the overload axial forces a displacement of the spindle 35 in the direction of entry 27 while simultaneously compressing the disc springs 134 . 136 occurs until the support body 124 with the existing at its free end support surface 129 on the opposite support surface 131 Of the head 31 of the cylinder is applied. The supporting body 124 So then it supports there so that the acting overload axial forces then from the spindle 35 over the support body 124 on the head 131 of the cylinder 21 be transferred without the needle bearing 123 would be damaged.

Due to the arrangement and the selected spring characteristics of the disc springs 134 . 136 So a certain force is given, which corresponds to a certain limit axial force, when it falls below the support body 124 is lifted and upon reaching or exceeding a shift of the spindle 35 together with the support body 124 in retraction direction 27 occurs until the support body 124 on the head 31 of the cylinder 21 is applied.

The flange-shaped approach 65 is at the transverse to the axis of rotation 43 the spindle 35 extending wall part 79 with here a total of eight locking recesses 38.1 to 38.8 provided, which to the cylinder bottom 53 are open to the outside. The locking recesses 38.1 to 38.8 are arranged in each case at equal angular distances from each other on an imaginary circumferential circle such that in each case two locking recesses are arranged diametrically opposite one another and consequently on one the axis of rotation 43 the spindle 35 containing straight lines are arranged. Each locking recess 38 is with conically inwardly tapered wall parts 70 designed and used to accommodate outwardly conically tapered wall parts 72 from locking bolt 40 . 140 , This is the conically tapered wall parts 72 having free endings 57 the respective locking bolt 40 . 150 Preferably such on the locking recesses 38 in the area of their conically tapered wall parts 70 tuned designed that a Durchströmspalt 71 is designed for the pressure medium. This Durchströmspalt 71 is in fluid communication with a gap 91 in the area of the radial edges of both the flange-shaped approach 65 as well as the opposite part of the head 31 of the cylinder 21 is arranged. This gap 91 is in fluid communication with a switching channel 47 which, in turn, is in fluid communication with channels 48 and 49 can be brought, over which the piston 22 on its respective pages 44 and 46 can be acted upon with pressure medium.

A first embodiment of a locking bolt 40 is in the 1 and 2 illustrated and a second embodiment of a locking bolt 140 is in 4 illustrated. The locking bolt 40 is unlike the locking bolt 140 in the area of his free end 57 designed cross-sectionally closed, while the locking bolt 140 as a hole nozzle 90 with one to his free end 57 towards open and concentric with its longitudinal axis 74 designed passageway 54 is provided. Except for this passage 54 but are the locking bolts 40 and 140 designed identically, wherein like reference numerals refer to like elements.

Every locking bolt 40 . 140 is as a preferably elongated cylinder pin 125 rotationally symmetrical to its longitudinal axis 74 designed. Every locking bolt 40 . 140 has a circular cylindrical outer contour 50 and a circular cylindrical inner contour, so it is designed as a rotary hollow body. Every locking bolt 40 . 140 also has a circular cylindrical recess 92 on that with parallel to the longitudinal axis 74 of the respective locking bolt 40 . 140 bordering wall parts is designed and that to the head 31 of the cylinder 21 opposite end 56 is open to the outside. This recess 92 serves for receiving and lateral support of a designed as a compression spring spring 39 , This is in the assembled state with a spring section 93 in the recess 92 added. The spring is supported 39 with one of their ends 95 on an inner surface 94 a radially inwardly extending support and conditioning level 60 of the locking bolt 40 . 140 from. The other end 96 the feather 39 is supported on an inner surface of a corresponding support and installation level 76 Of the head 31 of the cylinder 21 from.

At an axial distance from the inner surface of the support and conditioning stage 76 and in the extension direction 28 offset, is a radially outwardly extending abutment and counterface 98 for the locking bolt 40 . 140 provided perpendicular to the bearing recess 75 limiting wall parts is arranged. Every locking bolt 40 . 140 has at its head or spring-side end 59 a ring front edge 99 on, with a circumferential ring sealing surface 97 is designed and the unlocking 27 of the respective locking bolt 40 . 140 has. This ring sealing surface 97 lies sealingly on the likewise circumferential stop and counter sealing surface 98 Of the head 31 of the cylinder 21 when the respective locking bolt 40 . 140 after being exposed to the pressure medium in Entriege ment direction 27 exerted pressure forces has been transferred to its unlocked position. Under the then effective pressure forces a seal is achieved there, so that no leakage of pressure fluid along the outer surfaces of the respective locking bolt 40 . 140 occurs. In addition, the stop and sealing counter surface limits 96 advantageous the respective Entriegelungshub the locking bolt 40 . 140 ,

Every locking bolt 40 . 140 is with a small clearance in a cylindrical inner contour 98 having bore or bearing recess 75 parallel to the axis of rotation 43 the spindle 35 slidably mounted, so it can be based on the in the 1 . 2 and 4 shown locking position 41 in extension or unlocking direction 28 using the pressure medium against the spring forces the feather 39 be moved to its unlocked position, or vice versa after pressure relief in the region of its free locking end 57 from its unlocked position automatically, ie by that of the respective spring 39 on the respective locking bolt 40 . 140 exerted return spring forces, back into its locked position 41 be transferred. The bearing recess 75 thus has an inner diameter which is slightly larger than the outer diameter of the locking bolt 40 . 140 ,

Unlike the ones in the 1 and 2 shown locking bolt 40 is the in 4 illustrated locking bolt 140 as a hole nozzle 90 designed and has at its free end 57 that in the in 4 shown locking position 41 in the locking recess 38 protrudes, a central passageway 54 on. This passageway 54 is coaxial with the longitudinal axis 74 of the locking bolt 140 arranged. The passageway 54 has a comparatively small flow area and goes towards its other end 59 in a likewise designed with cylindrical wall parts channel part 78 over, which has a larger flow area. The channel part 78 goes again under training of the support and contact surface 60 in a recess 92 of the larger channel diameter 61 over, which is slightly larger than the outer diameter 62 in the mentioned recess 92 recorded spring 39 , The pressure spring is at one end at the support and conditioning level 60 of the locking bolt 140 At the other end, it relies on the support and investment level 76 of the lid or head 31 of the cylinder 21 from.

The locking bolt 140 indicates at its free end 57 one perpendicular to its longitudinal axis 74 arranged effective area 58 on, which can attack the fluid pressure medium to the locking bolt 140 starting from the in 4 shown locking position 41 in an unlocking position, in which he out of engagement with the locking recesses 38.1 to 38.8 stands, so a rotation of the spindle 35 in one direction of rotation 51 or an opposite direction of rotation 52 no longer blocked. The effective area 58 is much larger than the flow cross-section of the through-passage 54 in the region of the free end 57 of the locking bolt 40 . 140 , As a result, a secure unlocking of the locking bolt 40 . 140 allows. In addition, it can thereby at a pressure relief in the locking recesses 38 if desired, for the purpose of fixing the piston 22 with his piston rod 23 in a certain stroke position, or it is unintentional, for example in the event of leakage or total failure of the hydraulic system, the locking bolt 40 . 140 conditioned by the spring 39 exerted forces in its locking position 41 to be moved. It can in the case of locking bolts 140 located in the associated locking recess 38 located pressure medium through the passageway 54 of the locking bolt 140 through to the channel serving as a discharge channel 55 stream. In contrast, when using the locking bolt 40 during their movement from their unlocking position into the locking position 41 located in the associated locking recesses 38 located oil via the switching channel 47 and via the non-return valve 160 either in the flow channel 86 or in the return channel 87 displaced, depending on the position in which the locking member 171 designed as a shuttle valve Rückströmsperrmittels 160 located.

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

A particularly advantageous control of the locking cylinder 20 is with the circuit according to 5 achievable because this circuit and the control means used there make it possible that the pressure medium first the locking bodies 42 is supplied to convert them into their unlocked position and that then the pressure medium optionally the first working chamber 33 or the second working chamber 45 is fed to a movement of the piston 22 in the first direction 28 or in the second direction 27 to effect. As a result, the wear in the area of the locking bolts 40 and in the area of the locking recesses 38 can be minimized and it can not jamming the locking bolt 40 , especially at low switching pressures come.

In contrast, in the circuit according to 6 provided that the working fluid or the pressure means the locking bodies 142 is supplied to convert them into their unlocked position and that at the same time the pressure medium optionally the first working chamber 33 or the second working chamber 45 is fed to a movement of the piston 22 in the first direction 28 or in the second direction 27 to effect.

Certain essential to the invention switching or control elements that can be advantageously used in conjunction with both circuit variants are described in more detail below:
There are two as load-holding Senkbrems agent 150.1 . 150.2 designated load-holding lowering brake valves are provided, which cause when pressurized the piston 22 on his first page 46 with the one in the first chamber 33 located pressure medium to form a working pressure, a displacement of the piston 22 in a first direction 28 causes, at the same time in the second working chamber 45 on the second page 44 of the piston 22 a through the in the second working chamber 45 located pressure applied means acting back pressure, which is smaller than the working pressure in the first working chamber 33 , leaving an uncontrolled advance of the piston 22 in the first direction 28 is avoided, and vice versa upon application of the piston 22 on his second page 44 with the in the second working chamber 45 located pressure medium to form a working pressure, a displacement of the piston 22 in a second direction 27 opposite to the first direction 28 causes, simultaneously in the first working chamber 33 on the first page 46 of the piston 22 one by the one in the first working chamber 33 Pressure applied means located back pressure acts, which is smaller than the working pressure in the second working chamber 45 , leaving an 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 stroke position, a return flow of the pressure medium from both working chambers 33 . 45 lock so that the piston 22 through that into the work chamber 33 . 45 located pressure fluid is held securely in the desired stroke position.

Each load-holding lowering valve 150.1 . 150.2 has an inlet 153.1 . 153.2 , an outlet 154.1 . 154.2 and a control terminal 155.1 . 155.2 for the pressure medium, wherein the inlet 153.1 the first load-holding lowering valve 150.1 with the first working chamber 33 fluidly connected and wherein the inlet 153.2 the second load-holding lowering valve 150.2 with the second working chamber 45 fluidly connected, and wherein the outlet 154.1 the first load-holding lowering valve 150.1 with the control terminal 155.2 the second load-holding lowering valve 150.2 fluidly connected and wherein the outlet 154.1 the second load-holding lowering valve 150.2 with the control terminal 155.1 the first load-holding lowering valve 150.1 fluidly connected, and being connected to 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 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 valve 150.1 . 150.2 allows, but in the opposite direction blocks each, and that optionally the outlet 154.1 the first load-holding lowering valve 150.1 and thus the control connection 155.2 the second load-holding lowering valve 150.2 or the outlet 154.2 the second load-holding lowering valve 150.2 and thus the control connection 155.1 the first load-holding lowering valve 150.1 can be 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 valve 150.2 or via the first load-holding lowering brake valve 150.1 , preferably depending on the at the respective control terminal 155.1 . 155.2 effecting pressure.

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

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 the respective Rückströmsperrmittels 160 . 161 with the outlet 154.1 the first load-holding lowering valve 150.1 fluidly connected, and wherein the second inlet 165 the respective Rückströmsperrmittels 160 . 161 with the outlet 154.2 the second load-holding lowering valve 150.2 fluid-connected, and wherein the first inlet 164 the respective Rückströmsperrmittels 160 . 161 and the second inlet 165 the respective Rückströmsperrmittels 160 . 161 via a fluid channel 167 connected to each other, into the one with the outlet 166 the respective Rückströmsperrmittels 160 . 161 connected fluid channel 167 at a confluence point 168 opens so that from the confluence 168 a first channel part 169 of the fluid channel 167 and a second channel part 170 of the fluid channel 167 branches.

In the circuit according to 5 is also a locking member 171 for shutting off the first channel part 169 or the second channel part 170 provided, and wherein in the locked-off state of the second channel part 170 the first inlet 164 the Rückströmsperrmittels 160 , the first channel part 169 and the outlet 166 the Rückströmsperrmittels 160 fluidly connected, so that a pressure medium flow from both the first inlet 164 the Rückströmsperrmittels 160 to the outlet 166 the Rückströmsperrmittels 160 as well as from the outlet 166 the Rückströmsperrmittels 160 to the first inlet 164 the Rückströmsperrmittels 160 is permitted, and wherein, conversely, in the locked state of the first channel part 169 , the second inlet 165 the Rückströmsperrmittels 160 , the second channel part 170 and the outlet 166 the Rückströmsperrmittels 160 fluidly connected, so that a pressure medium flow from both the second inlet 165 the Rückströmsperrmittels 160 to the outlet 166 the Rückströmsperrmittels 160 as well as from the inlet 164 the Rückströmsperrmittels 160 to the second inlet 165 the Rückströmsperrmittels 160 is allowed.

In the circuit according to 5 is further provided that the respective Rückströmsperrmittel 156.1 . 156.2 a locking member 173.1 . 173.2 for inhibiting a flow of pressurized fluid from the inlet 153.1 . 153.2 to the outlet 154.1 . 154.2 the respective load-holding lowering brake means 150.1 . 150.2 characterized by the spring forces of a spring 174.1 . 174.2 is acted upon, so that opening the Rückströmsperrmittels 156.1 . 156.2 and thus a flow of pressurized fluid from the outlet 154.1 . 154.2 to the inlet 153.1 . 153.2 the respective load-holding lowering brake means 150.1 . 150.2 is only possible from a limit pressure of the pressure medium is exceeded, the value of a spring characteristic of the respective spring 174.1 . 174.2 depends. These feathers 174.1 and 174.2 are also good in 1 at the lower ends of the two load-holding lowering brake valves 150.1 . 150.2 seen.

Unlike the circuit according to 5 can according to a circuit according to 6 be provided that 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, which is the first channel part 169 and the second channel part 170 with regard to a pressure medium flow from the outlet 166 the Rückströmsperrmittels 161 to the first inlet 164 the Rückströmsperrmittels 161 and to the second inlet 165 the Rückströmsperrmittels 161 shut off and the one pressure fluid flow from the first inlet 164 the Rückströmsperrmittels 161 to the outlet 166 the Rückströmsperrmittels 161 and from the second inlet 165 the Rückströmsperrmittels 161 to the outlet 166 the Rückströmsperrmittels 161 allow.

The following is the operation of the lock cylinder 20 described in more detail:
In the in 1 shown as an example rest position of the locking cylinder 20 So while holding the piston 22 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 over the channel 48 or the channel 49 with the pressure medium working spaces 45 and 33 of the cylinder 21 fluidly connected, which is a pressurization of the piston 22 on its side facing the piston rod end 44 and / or on his to the cylinder bottom 53 pointing side 46 enable.

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

In addition to hydraulic locking by means of the load-holding lowering brake valves 150.1 . 150.2 is a mechanical security of the locking cylinder 20 via the locking unit 56 possible. This additional mechanical protection is particularly effective when leakage or failure or similar damage to the hydraulic system occurs. Because then grab the locking bolts 40 . 140 in the locking recesses 38 a, allowing a positive and bidirectional locking of the spindle 35 and thus the piston 22 given in the given stroke position. This engagement or blocking position of the cylinder bolt 40 . 140 is achieved in the moment in which an unwanted, in the channels 48 or 49 and thus also in the switching channel 47 impacting pressure relief occurs. Because then the respective locking bolt 40.1 . 40.2 ; 140.1 . 140.2 by the mechanical force of the compression springs 39 against the previously rotating flange approach 65 pressed until the respective locking bolt 40.1 and 40.2 respectively. 140.1 and 140.2 in the next possible locking recess 38 engages and thereby the further rotational movement of the spindle 35 blocked.

The operation of the lock cylinder will be described below 20 using the in 5 Shown circuit shown:
For example, a movement of the piston 22 and thus the piston rod 23 relative to the cylinder 22 in the extension direction 28 to reach, here is the flow channel 86 designated channel acted upon with pressure medium, ie it is by means of a pump not shown in the figures through the flow channel 86 supplied the pressure medium.

Up to a certain pressure, which depends on the spring characteristic of the spring 174.1 the backflow stop 156.1 depends on the pressure medium can not initially in the channel 49 and therefore not in the workspace 33 arrive, but first passes through the first inlet 164 in the first channel part 169 designed as a shuttle valve Rückströmsperrmittels 160 , whereby its blocking means 171 opening a flow path over the confluence 168 in the fluid channel 167 and from there via the outlet 166 in the switching channel 47 while substantially simultaneously closing the second channel part 165 in the in 5 Locking position shown on the left is moved.

At the same time, it becomes the control terminal 155 the second load-holding lowering valve 150.2 leading channel 88.1 pressurized with pressure medium. However, the pending pressure medium pressure still causes no opening of the second load-holding Senkbrems valve 150.2 , Because an opening of the load-holding lowering brake means 150.1 and 150.2 takes place against adjustable spring forces of a respective spring 80.1 respectively. 80.2 , Consequently, the respective load-holding lowering brake means opens 150.1 and 150.2 only from a certain, at the respective control terminal 155.1 respectively. 155.2 pending pressure medium pressure, depending on the springs 80.1 respectively. 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 only open when the Rückströmsperrmittel 156.2 respectively. 156.1 opens, ie here, when the respective Rückströmsperrventil against the spring force of the respective spring 174.2 respectively. 174.1 opens to a movement of the piston 22 in the extension direction 28 or in the retraction direction 27 to effect.

The pressure medium then flows through the switching channel first 47 to the pressure medium spaces in the area of the free ends 57 the locking bolt 40 and causes them from the locked position shown 41 in that direction 27 be transferred to their unlocked position. Once the sealing surfaces 97 the locking bolt 40 at the mating surfaces 98 abutment, it comes under a further supply of pressure medium in the flow channel 86 there to a further increase in pressure, which causes the spring-loaded Rückströmsperre 156.1 opens. Then the pressure medium over the channel 49 in the first working chamber 49 flow to a movement of the piston 22 and thus the piston rod 23 in the extension direction 28 to effect.

At the same time, it becomes the control terminal 155.2 the second load-holding lowering valve 150.2 leading channel 88.1 pressurized with a corresponding pressure, whereby, depending on the currently in the flow channel 86 acting pressure, the load-holding lowering brake valve 150.2 more or less wide opens to a flow of pressure medium from the second working space 45 over the canal 48 and via the second load-holding lowering valve 150.2 in the in 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 set backpressure depends 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, preferably inversely proportional to the working pressure. In this way, it is always achieved during driving that the piston 22 is "clamped" with one of its current direction opposite acting force, causing an uncontrolled advance of the piston 22 is prevented.

If the piston is then to be stopped in a desired stroke position, it is preferable to have both the flow channel 86 as well as the return channel 87 depressurized. 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 brake valves 150.1 and 150.2 so that's in the working chambers 33 and 45 located pressure medium can not escape from it. The piston 22 So it's between those on both sides 44 and 46 clamped existing pressure columns and fixed in its current stroke position.

A pressure relief at the channels 86 and 87 also affects the switching channel 47 accordingly, so that the locking bolts 40 by the spring forces of the springs acting on them 39 in that direction 28 from its unlocked position to the locking position shown in the figures 41 can be transferred. This can be in the pressure fluid spaces before the free locking ends 57 the locking bolt 40 located pressure medium over the channel 47 and the shuttle valve 160 here in the flow channel 86 flow back.

Depending on which current rotary position the spindle is 35 and thus the locking recesses 38 at a current holding stroke position of the piston 22 are located, the locking bolts engage 40 then either in the locking recesses 38 or are these at the head 31 of the cylinder 21 indicative end face of the locking recesses 38 containing ring approach 65 at, extending between two immediately adjacent locking recesses 38 are located. In such, any holding stroke position of the piston 22 is it in Normally not relevant, if the locking bolts 40 or 140 in the locking recesses 38 intervention. Of course, something else applies in the event of leakage or damage in the pressure medium system. Then it rotates the locking recesses 38 approach still slightly further until the locking bolt 40 . 140 in the nearest locking recess 38 engage. In the embodiments shown and described, however, it can only be a very small stroke of the piston 22 come, which lies in the millimeter range and which is completely sufficient under security aspects.

Should the piston 22 and with it the piston rod 23 starting from the in 5 schematically illustrated stroke position relative to the cylinder 21 in the opposite direction, ie in the retraction direction 27 be moved, the return channel 87 pressurized with pressure medium. Then the locking member 171 the shuttle valve 160 by the inflowing pressure medium in the in 5 shifted blocking direction shown on the right, so that then over the second inlet 165 in the second channel part 170 inflowing pressure medium over the discharge point 168 again in the fluid channel 167 and from there into the switching channel 47 can flow, in which case the first channel part 169 of the fluid channel 159 through the blocking means 171 is locked.

After unlocking the locking bolts 140 or after these are transferred to their unlocked position, opens spring-loaded Rückströmsperre 156.2 so that then pressure medium into the working chamber 45 can flow to the piston 22 in retraction direction 27 to move. At the same time, in turn, depending on the current working pressure, now in the flow channel 87 , the first load-holding lowering brake valve 150.1 over the with the control terminal 155.1 fluid-connected control channel 88.2 so controlled that in the working chamber 33 a back pressure is formed which is smaller than the operating pressure in the working chamber 45 so that also the movement of the piston 22 in the retraction direction 27 without an unwanted advance of the same takes place.

The operation of the lock cylinder will be described below 20 using the in 6 shown circuit 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 the example of the circuit according to 5 explained, so that reference can be made in this respect to the above description parts.

When the locking cylinder 20 over the flow channel 86 or the return channel 87 is acted upon with pressure medium, this now leads simultaneously to a loading of the switching channel 47 with pressure medium. As a result, the fluid pressure medium passes through the switching channel 47 , the gap 91 and the Durchströmspalt 71 in the locking recesses 38 such that by the oil pressure forming therein the locking bolts 140 against the spring force of the respective spring 39 from the in 6 shown locking position 41 are pressed into the unlocking position, not shown in the figures. At the same time there is a controlled leakage through the flow channel 54 each locking bolt 40 , So if, for example, the flow channel 86 is acted upon by a pressure medium flow, pressure medium via the parallel to the load-holding Senkbrems valve 150.1 switched backflow lock 156.1 in the channel 49 and from there to the first working chamber 33 arrive and can at the same time via the first check valve 84 the Rückströmsperrmittels 161 in the switching channel 47 reach. The pressure medium then flows through the first inlet 164 the Rückströmsperrmittels 161 in the first channel part 169 of the fluid channel 159 and from there via the estuary 168 in the branched fluid channel 167 and again from there into the switching channel 47 , Here is the second check valve 85 the Rückströmsperrmittels 161 closed, ie their locking member 172.2 locks the second channel part 170 ,

Once the locking bolts 140.1 and 140.2 are transferred to their unlocked position with further oil supply, the piston can 22 due to a simultaneous application of pressure medium on his cylinder bottom 53 indicative page 46 in the extension direction 28 move. As soon as the pressure medium flow in the flow channel 86 preferably drops to zero, close both the Rückströmsperren 156.1 and 156.2 as well as both load-holding lowering brake valves 150.1 and 150.2 , Almost simultaneously, the locking bolts 140 through the springs 39 in the extension direction 28 shifted so that it depends on the current position of the locking recesses 38 can snap into place there, so that in the locked position 41 the spindle 35 and thus the piston 22 both hydraulically and mechanically locked.

Is based on the above reached stroke position of the piston 22 this can be moved back in the retraction direction, the return channel 87 be acted upon with pressure medium, that is, the pressure medium can be supplied there. The pressure medium can then via the check valve 156.2 in the channel 48 arrive and from there into the working chamber 45 such that the side facing the rod end is side 44 of the piston 42 can be acted upon with pressure medium. At the same time passes from the return channel 87 a branched pressure medium flow via the second check valve 85 the Rückströmsperrmittels 161 again in the switching channel 47 while the first check valve 84 is closed. This leads in the same way, as already explained above, that the locking bolt 140 automatically, ie transferred without additional switching operation in their unlocked position. Then the piston moves 22 and with it the piston rod 23 in retraction direction 27 , wherein as well as above in connection with the circuit according to 5 explained in the working chamber 33 a back pressure acts, which is smaller than the working pressure in the working chamber 45 , so that again no uncontrolled advance of the piston 22 in the retraction direction 27 can occur.

It is therefore a characteristic process feature according to the in 6 shown circuit that the pressure means for the purpose of retraction and / or for the purpose of extending the piston 22 at least one page 44 or 46 of the piston 22 and at the same time the locking bolt 40 is supplied, wherein the locking bolt 40 against 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 one direction of rotation 51 or in an opposite direction of rotation 52 can turn with the consequence that the piston 22 according to the direction of rotation 51 or 52 in the extension direction 28 or in the retraction direction 27 is moved.

That through the channel 55 Backflowing pressure medium can, depending on which of the channels 86 or 87 is pressurized, either via the check valve 82 or over the check valve 83 in the channel 86 or in the channel 87 to be led back.

20

lock cylinders

21

cylinder

22

piston

23

piston rod

24

recess

25

fastener

26

fastener

27

retraction

(second Direction, Ent

riege development direction)

28

of extension

(first Direction)

29

Longitudinal axis of 21

30

cover

31

head (Cover)

32

approach

33

first working chamber

34

inner thread (Piston

thread)

35

spindle

36

external thread

(Spindle thread)

37

Not self-locking

thread

38

lock

recess may

38.1

to

38.8

lock

recess may

39

feather

40

locking bolt

40.1

locking bolt

40.2

locking bolt

41

locking position

42

locking body

43

Rotation axis of 35

44

first page of 22

45

second working chamber

46

second page of 22

47

switching channel

48

channel

49

channel

50

Outer contour of 40

51

direction of rotation

52

direction of rotation

53

cylinder base

54

Through channel

55

channel

56

locking unit

57

free The End

from 40 . 140

58

effective area

59

spring-sided The End

from 40 . 140

60

Support and support investment

step

61

Channel diameter

62

outer diameter

from 39

63

ring seal

64

ring seal

65

approach

66

approach

67

free end of 35

68

ring seal

69

cylinder bolt

70

Wall part of 38

71

throughflow

72

wall part

73

free lock

end of 40 . 140

74

longitudinal axis

from 40 . 140

75

bearing recess

(Drilling)

76

Support and support investment

step

77

End of 35

78

channel part

79

Wall part of 65

80.1

feather

80.2

feather

82

check valve

83

check valve

84

first return

Valve

85

second return

Valve

86

forward channel

87

Return channel

88.1

switching channel

88.2

switching channel

89

Inner contour of 75

90

hole nozzle

91

gap

92

recess

93

spring section

94

Inside surface of 60

95

End of 39

96

End of 39

97

Sealing surface

stop surface

98

Against sealing surface

99

front edge

120

first thrust

121

second thrust

122

roller bearing

123

needle roller bearings

124

support body

125

cylinder bolt

126

feather

127

first section bearings

128

free end of 124

129

support surface

130

second section bearings

131

support surface

132

diameter

133

diameter

134

Belleville spring

135

Belleville spring assembly

136

Belleville spring

137

roller bearing

138

needle roller bearings

140

locking bolt

140.1

locking bolt

140.2

locking bolt

142

locking body

142.1

locking body

142.2

locking body

150.1

first Load Holding

Over-center agent

150.2

second Load Holding

Over-center agent

153.1

Admission of 150.1

153.2

Admission of 150.2

154.1

Outlet of 150.1

154.2

Outlet of 150.2

155.1

control connection

from 150.1

155.2

control connection

from 150.2

156.1

Rückströmsperrmittel

156.2

Rückströmsperrmittel

159

fluid channel

160

Rückströmsperrmittel

161

Rückströmsperrmittel

164

first inlet

from 160 . 161

165

second inlet

from 160 . 161

166

Outlet of 160 . 161

167

fluid channel

168

opening point

from 167

169

first channel part

from 159

170

second channel part

from 159

171

Locking member of 160

172.1

first locking member

from 161

172.2

second locking member

from 161

173.1

Locking member of 156.1

173.2

Locking member of 156.2

174.1

feather

174.2

feather

Claims (12)

Locking cylinder ( 20 ) with a cylinder ( 21 ) and a piston ( 22 ), using either side of the piston ( 22 ) into a first working chamber ( 33 ) and into a second working chamber ( 45 ) deliverable fluid pressure medium parallel to the longitudinal axis ( 29 ) of the cylinder ( 21 ) is movable, and with a piston thread ( 34 ), which forms a non-self-locking thread ( 37 ) with a spindle thread ( 36 ) a spindle ( 35 ) is engaged, which is parallel to the longitudinal axis ( 29 ) of the cylinder ( 21 ) arranged rotary axis ( 43 ) is rotatable and the at least one outwardly open locking recess ( 38 ), in which at least one acted upon by spring force of a spring locking body ( 42 . 142 ) can engage, which against rotation about the axis of rotation ( 43 ) of the spindle ( 35 ) and secured to the cylinder ( 21 ), but is mounted relative to this movable, and by means of the spring force of the spring ( 39 ) in a locking position ( 41 ) is convertible, in which he in the locking recess ( 38 ) of the spindle ( 35 ) engages, so that then a 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 ) can be converted into an unlocking position, in which the spindle ( 35 ) about its axis of rotation ( 43 ) is rotatable to a movement of the piston ( 22 ) along the cylinder ( 21 ), and wherein control means for controlling the Movement of the piston ( 22 ) and the locking body ( 42 . 142 ) or the locking body ( 42 . 142 ), characterized in that at least one first load-holding lowering brake means ( 150.1 ) with the first working chamber ( 33 ) is fluid-connected and that at least one second load-holding lowering brake 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 ) on its first page ( 46 ) with the one in the first working chamber ( 33 ) pressure medium to form a working pressure, the displacement of the piston ( 22 ) in a first direction ( 28 ), simultaneously in the second working chamber ( 45 ) on the second page ( 44 ) of the piston ( 22 ) by the in the second working chamber ( 45 ) applied pressure medium acting back pressure acts, which is smaller than the working pressure in the first working chamber ( 33 ), so that an uncontrolled advance of the piston ( 22 ) in the first direction ( 28 ) and, conversely, when the piston is pressurized ( 22 ) on its second page ( 44 ) with the one in the second working chamber ( 45 ) pressure medium to form a working pressure Ar, the displacement of the piston ( 22 ) in a second direction ( 27 ) opposite to the first direction ( 28 ), at the same time in the first working chamber ( 33 ) on the first page ( 46 ) of the piston ( 22 ) by the in the first working chamber ( 33 ) applied pressure medium acts which is smaller than the working pressure in the second working chamber ( 45 ), so that an 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 stroke position, a return flow of the pressure medium from both working chambers ( 33 . 45 ), so that the piston ( 22 ) by the in the working chambers ( 35 . 45 ) located pressure medium is held in the desired stroke position. Locking cylinder according to claim 1, characterized in that the of the load-holding lowering brake means ( 150.1 . 150.2 ) controlled back pressure depending on the respective, a movement of the piston ( 22 ) along the cylinder ( 21 ) causing working pressure is controlled. Locking cylinder according to claim 2, characterized in that the of the load-holding lowering brake means ( 150.1 . 150.2 ) controlled back pressure depending on the respective, a movement of the piston ( 22 ) along the cylinder ( 21 ) working pressure is controlled, so that decreases with increasing working pressure of the simultaneously acting back pressure. Locking cylinder according to claim 3, characterized that the back pressure is controlled inversely proportional to the working pressure is. Locking cylinder according to one of claims 1 to 4, characterized in that the load-holding lowering brake 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 lowering brake means ( 150.1 ) with the first working chamber ( 33 ) is fluidly connected and the inlet ( 153.2 ) of the second load-holding lowering brake means ( 150.2 ) with the second working chamber ( 45 ) is fluidly connected, and wherein the outlet ( 157.1 ) of the first load-holding lowering brake means ( 150.1 ) with the control connection ( 155.2 ) of the second load-holding lowering brake means ( 150.2 ) is fluidly connected and the outlet ( 154.1 ) of the second load-holding lowering brake means ( 150.2 ) with the control connection ( 155.1 ) of the first load-holding lowering brake means ( 150.1 ) is fluidly connected, and wherein with the inlet ( 153.1 . 153.2 ) and the outlet ( 154.1 . 154.2 ) of the respective load-holding lowering brake means ( 150.1 ., 150.2 ) each 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 in 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 connection ( 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 connection ( 155.1 ) of the first load-holding lowering brake means ( 150.1 ) can be 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 lowering brake means ( 150.2 ) or via the first load-holding lowering brake means ( 150.1 ) depending on the at the respective control terminal ( 155.1 . 155.2 ) acting 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 ), so that when 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 ) with pressure medium, this the locking body ( 42 . 142 ) or the locks bodies ( 42 . 142 ) is supplied to convert this or this in his or her unlocking 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 ( 154.2 ) at least one Rückströmsperrmittel ( 160 . 161 ) is arranged, which at a loading of the outlet ( 154.1 ) of the first load-holding lowering brake means ( 150.1 ) with pressure medium, a pressure medium flow to the outlet ( 154.2 ) of the second load-holding lowering brake means ( 150.2 ) and vice versa when the outlet ( 154.2 ) of the second load-holding lowering brake means ( 150.2 ) with pressure medium, a pressure medium flow to the outlet ( 154.1 ) of the first load-holding lowering brake means ( 150.1 ) prevented, and in both cases a supply of the pressure medium to the locking body or the locking bodies ( 42 . 142 ), so that this or these is transferred to his or her unlocking position or will be. Locking cylinder according to claim 7, characterized in that the Rückströmsperrmittel ( 160 ) 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 ( 160 ) with the outlet ( 154.1 ) of the first load-holding lowering brake means ( 150.1 ) is fluidly connected, and wherein the second inlet ( 165 ) of the Rückströmsperrmittels ( 160 ) with the outlet ( 154.2 ) of the second load-holding lowering brake means ( 150.2 ) is fluidly connected, 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 connected to one another with the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) connected fluid channel ( 167 ) at a confluence point ( 168 ), so that from the confluence point ( 168 ) a first channel part ( 169 ) of the fluid channel ( 167 ) and a second channel part ( 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 locked state of the second channel part ( 170 ) the first inlet ( 164 ) of the Rückströmsperrmittels ( 160 ), the first channel part ( 169 ) and the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) are fluidly connected, so that a flow of pressure medium from both the first inlet ( 164 ) of the Rückströmsperrmittels ( 160 ) to the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) as well as from the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) to the first inlet ( 164 ) of the Rückströmsperrmittels ( 160 ) is permitted, and vice versa in the locked state of the first channel part ( 169 ) the second inlet ( 165 ) of the Rückströmsperrmittels ( 160 ), the second channel part ( 170 ) and the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) are fluidly connected so that a flow of pressurized fluid from both the second inlet ( 165 ) of the Rückströmsperrmittels ( 160 ) to the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) as well as from the outlet ( 166 ) of the Rückströmsperrmittels ( 160 ) to the second inlet ( 165 ) of the Rückströmsperrmittels ( 160 ) is allowed. Locking cylinder according to claim 7, characterized in that the Rückströmsperrmittel ( 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 Rückströmsperrmittels ( 161 ) with the outlet ( 154.1 ) of the first load-holding lowering brake means ( 150.1 ) is fluidly connected, and wherein the second inlet ( 165 ) of the Rückströmsperrmittels ( 161 ) with the outlet ( 154.2 ) of the second load-holding lowering brake means ( 150.2 ) is fluidly connected, 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 ) at a confluence point ( 168 ), so that from the confluence point ( 168 ) a first channel part ( 169 ) of the fluid channel ( 167 ) and a second channel part ( 170 ) of the fluid channel ( 167 ) branches off, and wherein a first locking member ( 172.1 ) for shutting off the first channel part ( 169 ) and a second blocking member ( 172.2 ) for shutting off the second channel part ( 170 ) is provided, which 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 Rückströmsperrmittels ( 161 ) to the first inlet ( 164 ) of the Rückströmsperrmittels ( 161 ) and to the second inlet ( 165 ) of the Rückströmsperrmittels ( 161 ) and the one pressure medium flow from the first inlet ( 164 ) of the Rückströmsperrmittels ( 161 ) to the outlet ( 166 ) of the Rückströmsperrmittels ( 161 ) and from the second inlet ( 165 ) of the Rückströmsperrmittels ( 161 ) to the outlet ( 166 ) of the Rückströmsperrmittels ( 161 ) allow. Locking cylinder according to claim 5, characterized in that the working means or the pressure means the locking body ( 142 ) or the locking bodies ( 142 ) is supplied to transfer this or this 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 a movement of the piston ( 22 ) in the first direction ( 28 ) or in the second direction ( 27 ) to effect. Locking cylinder according to claim 5, characterized in that the working means or the pressure medium first the locking body ( 42 ) or the locking bodies ( 42 ) is supplied in order to transfer this or this in his or her 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 direction ( 27 ) to effect. Locking cylinder according to claim 11, characterized in that the respective Rückströmsperrmittel ( 156.1 . 156.2 ) a blocking member ( 173.1 . 173.2 ) for preventing fluid flow 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 an opening of 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 ) is only possible from a limit pressure of the pressure medium is exceeded, whose value from a spring characteristic of the respective spring ( 174.1 . 174.2 ) depends.