EP1541876B1 - Lock cylinder - Google Patents

Abstract

The locking cylinder unit (20) includes a cylinder (21) and a piston (22), engaged with a spindle (35) by a non-self-locking thread (37). The spindle has at least one locking recess (38) containing a sprung locking body for locking bolts to engage in them. Several locking bodies are made in the form of separate movable locking bolts.

Description

The invention relates to a locking cylinder with 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 rotatable about a rotational 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 body acted upon by spring force of a spring can engage, which is secured against rotation about the axis of rotation of the spindle and movable relative to the cylinder is mounted and which is translatable by means of the spring force of the spring in a locking position in which it engages in the locking recess of the spindle, so that then rotation of the spindle is blocked about its axis of rotation, and wherein the locking body using a it is fluid working 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.

Such a locking cylinder has become known from JP 083 034 10 A. 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.

On the outer circumference of the locking piston, a circumferential seal is provided which seals a pressure medium acted upon pressure medium space to the end cap of the cylinder.

This construction of a locking unit is complicated and takes up comparatively much space. For unlocking or locking the design-related large and compact and therefore important locking piston comparatively large forces are needed and / or it must comparatively long locking or locking times are accepted, which also means a corresponding security risk. The locking piston must be sealed at its outer periphery with a circumferential seal, which leads to corresponding frictional forces when moving the locking piston for the purpose of locking or unlocking, whereby the efficiency of this locking cylinder is limited.

The ball screw is clamped to the cylinder via a ball bearing and arranged at the free end of the spindle shaft slide bearing clamped that a movement of the spindle in the longitudinal direction of the cylinder is not possible, while a rotation of the spindle about its longitudinal axis is possible. For this purpose, the free end of the spindle shaft slidably supported on an inner surface of the end cap of the cylinder and the ball bearing is fixed by means of a screwed onto an external thread of the ball screw nut against a transverse to the cylinder paragraph.

This design is limited to applications where only relatively small loads can be lifted. For larger loads, however, it can lead to wear up to the feeding of the plain bearing. This can lead to the formation and detachment of metal chips or particles, which may affect the function of the locking unit, up to a blockade of the locking piston. This means an unacceptable security risk.

The control of the locking piston having the locking unit and the control of the movement of the piston take place in this construction via mechanically coupled directional control valves such that it can come in the raising or lowering of the load to an undesirable advance of the piston. This means a piston movement that is difficult to control. Particularly at elevated pressures or piston speeds, cavitation may occur at the piston seal and the piston rod, which means a safety risk and correspondingly limits the service life.

It is therefore an object of the invention to provide a locking cylinder 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 which is translatable by means of the spring force of the spring into a locking position, in which it engages in the locking recess of the spindle to form a positive and bidirectional locking of the spindle, 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 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 and wherein a plurality of locking bodies are designed as a separately movable locking bolt.

The fact that the locking body are designed as a separately movable locking pin, jamming or tilting can be avoided in the lock. In contrast to the prior art, such locking bolts are simple and inexpensive to produce and require only a minimal installation and control room, so that the space gained can be used to advantage for other elements and / or tasks or provided an overall smaller and lighter locking cylinder can be.

Due to the above measures only relatively small locking and unlocking forces are needed. As a result, the locking cylinder in the region of the locking unit can be made more space-saving or lighter overall. This also allows significantly reduced locking and unlocking times. Finally, when using the separately movable locking bolt no circumferential seals between them and the cylinder wall needed.

In this way, therefore, a locking cylinder can be provided which allows for a simple and space-saving locking construction higher reliability and has a better efficiency.

In an advantageous development, it can be provided that the locking bolts are arranged to be movable independently of one another, that is to say in particular without mechanical positive coupling between the locking bolts. According to a further embodiment, it can be provided that only two separate locking bolts are used. This further reduces the risk of jamming or jamming.

According to yet another embodiment, it can be provided that the locking bolts are each mounted with a small clearance in a bearing recess of the head of the cylinder which is open towards the side of the locking recesses.

It may be of particular advantage if the locking bolts are cylindrical bolts, which preferably have a circular-cylindrical outer contour. It may therefore be particularly advantageous if the locking bolts each have a conical outer contour at their free locking ends and / or if the cylinder bolts are each mounted in a cylindrical recess having a cylindrical inner contour bearing recess with little play.

According to a further embodiment variant, it can be provided that the locking bolts each have an outwardly open recess relative to their respective spring, in which the spring configured in each case as a compression spring is received with a spring section and which there with one of its ends respectively at one Inner surface of the respective locking bolt is supported, with its other end is supported on the head of the cylinder.

According to a further embodiment, it can be provided that the locking bolts each have a circumferential sealing surface which points in the unlocking direction of the respective locking bolt, and in the unlocking position of the respective locking bolt and under the then exerted by the working means in the unlocking pressure forces on a circumferential counter-sealing surface of Head of the cylinder sealingly abuts.

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

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

According to a further embodiment, it may be provided that the sealing surface is arranged on an annular end edge of the locking bolt at its end associated with the spring.

According to a further embodiment, it may be provided that the locking bolts are designed to be cross-sectionally closed, so that leakage of the working fluid along the respective locking bolt is prevented when sealing surface of the respective locking bolt sealingly abutting the respective counter-sealing surface.

According to a further advantageous embodiment, it can be provided that the locking bolts each have a through channel, which opens in the locking position in the region of the locking recess, preferably in the locking recess and the other end is connected to a preferably serving as a discharge channel channel, so that the fluid working at a movement of the respective locking bolt can flow from its unlocking position into its locking position from the respective locking recess in the aforementioned channel.

According to a further advantageous embodiment, it can be provided that the respective passage channel has at its end of the respective locking bolt associated with the locking recess a Durchströmquerschnitt, which is much smaller than an effective surface 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, it can be provided that the respective passage in the respective locking bolt to form a Support and investment level laterally expanded for each spring designed as a compression spring.

It is understood that the above measures can be combined as desired in the feasibility of a locking cylinder of the type mentioned in order to provide a locking cylinder with correspondingly 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 slidably mounted therein piston 22. The piston 22 is sealed relative to the cylinder inner wall 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 allow a pressure-medium-assisted movement of the piston 22 in a direction of unlocking referred to as the second direction or unlocking direction 27 or in a direction also referred to as the first direction of extension 28.

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

The piston 22 forms a projection 32 which is non-rotatably connected to the piston rod 23. The piston 22 is designed as a tubular hollow body and has an internal thread 34, also referred to as a piston thread. This is engaged with a spindle thread designated as 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 achtgängige trapezoidal coarse thread, which together form a non-self-locking thread 37.

For attachment of the locking cylinder 20, the piston rod 23 at its free end a here designed with an eyelet fastener 25, and a correspondingly shaped fastener 26 is mounted opposite to the head 31 of the cylinder 21.

The pressure medium can be fed via the channels 48 and 49 on both sides 44 and 46 of the piston 22 into a first working chamber 45 and into a second working chamber 33 in order to achieve a movement of the piston 22 along the cylinder 21 in the retraction direction 27 or in the extension direction 28 can. In this case, the first working chamber 45 is sealed relative to the second working chamber 33 via the annular seal 68 of the piston 22.

In the area of the free end 67 of the spindle 35 facing away end 77 of the spindle 35, this is rotatably connected to a flange-shaped projection 65. This has in the region of its cylinder bottom side end a transversely or perpendicular to the axis of rotation 43 of the spindle 35 extending, here annular wall portion 79. This is mounted on the free end 67 of the spindle 35 side facing by a first thrust bearing 120, here in the form of a first ring bearing 127, which is designed here as a needle bearing 138, at a support and investment level of the cylinder extension 66. This as a rolling bearing 137 designed ring bearing 127 serves to absorb the forces acting in the extension direction 28 on the spindle 35 axial forces. In order to be able to absorb the axial forces acting on the spindle 35 in the retraction direction 27 in the opposite direction to the extension direction 28, two measures are taken:

For receiving the operating axial forces acting on the spindle 35 during normal operation of the locking cylinder 20 in the first direction 28, a second thrust bearing 121 is provided in the form of a second annular bearing 130 arranged at the head end 77 of the spindle 35. This thrust bearing 121 is also designed as a roller bearing 122 in the form of a needle bearing 123. It is on a coaxial with the axis of rotation 43 of the spindle 35 fixedly connected to the spindle 35 supporting body 124 received in the form of a cylinder pin 125 which extends in the direction of the cylinder bottom or head 31 of the cylinder 21 and the coaxial with the axis of rotation 43 spindle 35 is arranged ,

Adjoining the needle bearing 123 in the retraction direction 27 is a disc spring package 135, which consists of a plurality of disc springs 134, 136. In the embodiment shown, five disc springs 134 and five disc springs 136 are provided. In this case, the plate springs 134 and the plate springs 136 are each alternately successively preferably arranged such that in each case the spring travel of each plate spring 134, 136 is available for a resilient mounting of the spindle 35. The plate springs 134, 136 are selected in terms of their spring characteristics and arrangement such that in the regular driving operation, when the piston 22 is moved in the retraction direction 27, the case not on the self-locking thread 37 and the spindle 35 transmitted dynamic resulting forces absorbed, that are compensated, so that the support body 124 is always lifted from the head 31 of the cylinder bottom of the cylinder 21.

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

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, which is located in the two working chambers 33 and 45 and with these fluid-connected channels 49 and 48, held "clamped", so that even under permissible high static loads, which are to be held or moved by the locking cylinder 20, the support body 124 is always lifted from the head 31 of the cylinder 21. In this case, therefore, the static load to be retained by means of the locking cylinder 20 and the axial forces transmitted thereto to the spindle 35 are received essentially via the piston 22 and the pressure medium acting on it and via the adjacent cylinder walls.

However, if a claim occurs, so z. B. leakage occurs in the area or a fraction of a pressure medium line, 27 acting overload axial forces can occur in the retraction direction, which is no longer received by the small needle bearing 123 without destruction can be. Because this second needle bearing 123 has a relation 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 for a space-saving design of the locking cylinder 20 in the locking and storage area. The wear the used disc springs 134 and 136, so that upon application of the overload axial forces a displacement of the spindle 35 in the retraction 27 with simultaneous compression of the disc springs 134, 136 occurs until the support body 124 with the present 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 then supported there so that the acting overload axial forces are then transferred from the spindle 35 via the support body 124 on the head 131 of the cylinder 21 without the needle bearing 123 would be damaged.

By 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 at which falls below the support body 124 is lifted and upon reaching or exceeding a displacement of the spindle 35 together with the Support body 124 in the retraction 27 occurs until the support body 124 bears against the head 31 of the cylinder 21.

The flange-shaped projection 65 is provided on the transverse to the axis of rotation 43 of the spindle 35 extending wall portion 79 with here a total of eight locking recesses 38.1 to 38.8, which are open to the cylinder bottom 53 out to the outside. The locking recesses 38.1 to 38.8 are in arranged at equal angular distances from one another on an imaginary circumferential circle such that in each case two locking recesses are arranged diametrically opposite each other and consequently are arranged on a line containing the axis of rotation 43 of the spindle 35. Each locking recess 38 is configured with conically inwardly tapering wall portions 70 and serves to receive outwardly conically tapered wall portions 72 of locking bolts 40, 140. Here, the tapered wall portions 72 having free end 57 of the respective locking bolt 40, 150 is preferably designed in such a manner on the locking recesses 38 in the region of their conically tapered wall parts 70, that a Durchströmspalt 71 is formed for the pressure medium. This Durchströmspalt 71 is in fluid communication with a gap 91 which is arranged in the region of the radial edges of both the flange-shaped projection 65 and the opposite part of the head 31 of the cylinder 21. This gap 91 is in fluid communication with a switching channel 47, which in turn can be brought into fluid communication with channels 48 and 49, via which the piston 22 can be acted upon by pressure medium on its respective sides 44 and 46.

A first embodiment of a locking bolt 40 is shown in Figures 1 and 2 and a second embodiment of a locking bolt 140 is illustrated in Figure 4. The locking pin 40 is in contrast to the locking pin 140 in the region of its free end 57 designed to be cross-sectionally closed, while the locking pin 140 as a hole nozzle 90 with an open towards his free end 57 and concentric with its longitudinal axis 74 through-channel 54 is provided. Except for this passage 54, however, the locking bolts 40 and 140 are identical, wherein like reference numerals refer to like elements.

Each locking bolt 40, 140 is designed as a preferably elongated cylinder pin 69 rotationally symmetrical to its longitudinal axis 74. Each locking bolt 40, 140 has a circular cylindrical outer contour 50 and a circular cylindrical inner contour, is thus designed as a rotary hollow body. Each locking bolt 40, 140 also has a circular cylindrical recess 92 which is formed with parallel to the longitudinal axis 74 of the respective locking bolt 40, 140 delimiting wall parts and which is open to the head 31 of the cylinder 21 opposite end 56 to the outside. This recess 92 serves to receive and lateral support of a designed as a compression spring spring 39. This is received in the mounted state with a spring portion 93 in the recess 92. 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 support and contact stage 76 of the head 31 of the cylinder 21.

Offset at an axial distance from the inner surface of the supporting and contact stage 76 and in the extension direction 28, a radially outwardly extending abutment and counter-sealing surface 98 for the locking pin 40, 140 is provided, which is arranged perpendicular to the wall portions bounding the bearing recess 75 , Every locking bolt 40, 140 has at its head or spring-side end 59 a ring end edge 99, which is designed with a circumferential annular sealing surface 97 and in the unlocking 27 of the respective locking bolt 40, 140 has. This ring-sealing surface 97 is sealingly against the likewise circumferential abutment and counter-sealing surface 98 of the head 31 of the cylinder 21, when the respective locking pin 40, 140 has been transferred into its unlocked position after being subjected to the pressing forces exerted by the pressure medium in unlocking 27 , 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 abutment and Abdichtgegenfläche 96 advantageously limits the respective Entriegelungshub the locking pins 40, 140th

Each locking bolt 40, 140 is slidably mounted parallel to the axis of rotation 43 of the spindle 35 with little clearance in the bore or bearing recess 75 having a cylindrical inner contour 98, that is, starting from the locking position 41 shown in FIGS. 1, 2 and 4. or unlocking 27 are moved by means of the pressure medium against the spring forces of the spring 39 in its unlocked position, or vice versa after pressure relief in the region of its free locking end. 57 are automatically transferred from its unlocked position, ie by the force exerted by the respective spring 39 on the respective locking bolt 40, 140 restoring spring forces, again in its locking position 41. The bearing recess 75 thus has an inner diameter slightly larger than the outer diameter of the locking bolt 40, 140.

In contrast to the locking bolts 40 shown in FIGS. 1 and 2, the locking bolt 140 illustrated in FIG. 4 is configured as a hole nozzle 90 and has a free end 57 which projects into the locking recess 38 in the locking position 41 shown in FIG central passageway 54. This through-passage 54 is arranged coaxially with the longitudinal axis 74 of the locking bolt 140. The through-passage 54 has a comparatively small through-flow cross-section and, in the direction of its other end 59, merges into a channel part 78 which is likewise designed with cylindrical wall parts and which has a larger flow cross-section. The channel part 78 in turn, forming the support and contact surface 60 in a recess 92 of the larger channel diameter 61, which is slightly larger than the outer diameter 62 of the spring 39 received in said recess 92. The compression spring is at one end to the support And investment level 60 of the locking bolt 140 and is supported at the other end of the support and investment stage 76 of the lid or head 31 of the cylinder 21 from.

The locking bolt 140 has at its free end 57 a perpendicular to its longitudinal axis 74 arranged active surface 58 to which the fluid pressure medium can act to transfer the locking bolt 140, starting from the locking position 41 shown in Figure 4 in an unlocking position, in which he is out of engagement with the locking recesses 38.1 to 38.8, ie a rotation of the spindle 35 in a rotational direction 51 or an opposite direction of rotation 52 is no longer blocked. The active surface 58 is much larger than the flow cross-section of the through-channel 54 in the region of the free end 57 of the locking bolt 40, 140. This enables a secure unlocking of the locking bolt 40, 140. In addition, it can be at a pressure relief in the locking recesses 38, it is intended, for the purpose of fixing the piston 22 with its piston rod 23 in a certain stroke position, or be it unintentionally, for example in the event of leakage or a total failure of the hydraulic system, the locking bolt 40, 140 are moved due to the forces exerted by the spring 39 forces in its locking position 41. In this case, in the case of the locking bolts 140, the pressure medium located in the associated locking recess 38 can flow through the through-passage 54 of the locking bolt 140 into the channel 55 serving as the relief channel. In contrast, when using the locking pin 40 in their movement from their unlocking position into the locking position 41 located in the associated locking recesses 38 Ö1 displaced via the switching channel 47 and the Rückströmsperrmittel 160 either in the flow channel 86 or in the return channel 87, depending after, in which position the locking member 171 of designed as a shuttle valve Rückströmsperrmittels 160 is located.

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

A particularly advantageous control of the locking cylinder 20 can be achieved with the circuit of Figure 5, because this circuit and the control means used there make it possible that the pressure medium is first supplied to the locking bodies 42 in order to convert them into their unlocked position and then the pressure medium either 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. 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 the locking bolts 40 can not become jammed, in particular at low switching pressures.

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

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

There are two designated as a load-holding Senkbrems means 150.1, 150.2 load holding Senkbrems valves are provided which cause when pressurizing the piston 22 on its first side 46 with the in the first chamber 33 pressure medium to form a working pressure, the causing 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, a counter pressure exerted by the pressure medium in the second working chamber 45 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 is avoided, and that conversely upon application of the piston 22 on its second side 44 with the pressure medium in the second working chamber 45 to form a working pressure, the displacement of the piston 22 in a second direction 27 opposite to the first direction 28 causes, at the same time in the first working chamber 33 on the first side 46 of the piston 22 a pressure exerted by the pressure medium in the first working chamber 33 acts counterpressure, 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 Senkbrems means 150.1, 150.2 at a desired pressure relief for the purpose of holding the piston 22 in a desired stroke position a backflow of the pressure medium from both working chambers 33, lock 45, so that the Piston 22 through the in the working chamber 33, 45 located pressure medium is held securely in the desired stroke position.

Each load-holding lowering brake valve 150.1, 150.2 has an inlet 153.1, 153.2, an outlet 154.1, 154.2 and a control connection 155.1, 155.2 for the pressure medium, wherein the inlet 153.1 of the first load-holding lowering valve 150.1 fluidly connected to the first working chamber 33 and wherein the inlet 153.2 of the second load-holding lowering valve 150.2 is fluidly connected to the second working chamber 45, and wherein the outlet 154.1 of the first load-holding lowering valve 150.1 is fluidically connected to the control port 155.2 of the second load-holding lowering valve 150.2 and wherein the outlet 154.1 of the second load-holding lowering brake valve 150.2 is fluidically connected to the control port 155.1 of the first load-holding lowering valve 150.1, and wherein with the inlet 153.1, 153.2 and the outlet 154.1, 154.2 of the respective load-holding lowering valve 150.1, 150.2 each a backpressure blocking means 156.1, 156.2 is fluidly connected, each having a flow of the pressure medium of 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 the opposite direction respectively blocks, 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 lowering brake valve 150.2 or the outlet 154.2 of the second load-holding Senkbrems valve 150.2 and thus the control port 155.1 of the first load-holding Senkbrems valve 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 training of the respective counterpressure, which is effected via the second load-holding lowering brake valve 150.2 or via the first load-holding lowering brake valve 150.1, preferably as a function of the pressure acting on the respective control connection 155.1, 155.2.

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

It is further provided that the non-return means 160, 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 respective non-return means 160, 161 with the outlet 154.1 of first load-holding counterbalance valve 150.1 is fluidly connected, and wherein the second inlet 165 of the respective Rückströmsperrmittels 160, 161 fluidly connected to the outlet 154.2 of the second load-holding Senkbrems valve 150.2, and wherein the first inlet 164 of the respective Rückströmsperrmittels 160, 161 and the second Inlet 165 of the respective Rückströmsperrmittels 160, 161 are connected to each other via a fluid channel 167, into which a connected to the outlet 166 of the respective Rückströmsperrmittels 160, 161 fluid channel 167 opens at an orifice 168, so that from the discharge 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.

In the circuit according to FIG. 5, a blocking member 171 is provided for shutting off the first channel part 169 or the second channel part 170, and in the shut-off state of the second channel part 170 the first inlet 164 of the non-return means 160, the first channel part 169 and the outlet 166 of FIG Backflow blocking means 160 are fluidly connected, so that a pressure medium flow from both the first inlet 164 of the Rückströmsperrmittel 160 to the outlet 166 of Rückströmsperrmittel 160 and the outlet 166 of the Rückströmsperrmittel 160 to the first inlet 164 of the Rückströmsperrmittel 160 is allowed, and vice versa, in the locked state of the first Portion 169, the second inlet 165 of the Rückströmsperrmittels 160, the second channel portion 170 and the outlet 166 of the Rückströmsperrmittels 160 fluidly connected, so that a pressure fluid flow from both the second inlet 165 of the Rückströmsperrmittel 160 to the outlet 166 of the Rückströmsperrmittels 160 as well as from the inlet 164 of the Rückströmsperrmittels 160 to the second inlet 165 of the Rückströmsperrmittel 160 is allowed.

In the circuit according to FIG. 5, it is further provided that the respective non-return blocking means 156.1, 156.2 has a blocking 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 lowering brake means 150.1, 150.2, which is acted upon by spring forces of a spring 174.1, 174.2, so that an opening of the Rückströmsperrmittels 156.1, 156.2 and consequently a pressure medium flow from the outlet 154.1, 154.2 to the inlet 153.1, 153.2 of the each 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 which depends on a spring characteristic of the respective spring 174.1, 174.2. These springs 174.1 and 174.2 are also well visible in Figure 1 at the lower ends of the two load-holding lowering valves 150.1, 150.2 there.

In contrast to the circuit according to FIG. 5, according to a circuit according to FIG. 6 it can be provided that a first blocking element 172.1 is provided for shutting off the first channel part 169 and a second blocking element 172.2 is provided for shutting off the second channel part 170 which comprises the first channel part 169 and the first channel part 169 second passage portion 170 with respect to a flow of pressurized fluid from the outlet 166 of the Rückströmsperrmittels 161 to the first inlet 164 of the Rückströmsperrmittels 161 and the second inlet 165 of the Rückströmsperrmittels 161 shut off and the one Druckmittelströmung from the first inlet 164 of Rückströmsperrmittels 161 to the outlet 166 of Rückströmsperrmittels 161 and the second inlet 165 of Rückströmsperrmittels 161 to the outlet 166 of Rückströmsperrmittels 161 allow.

The operation of the locking cylinder 20 is described in more detail below:

In the rest position of the locking cylinder 20 shown by way of example in FIG. 1, that is to say when holding the piston 22 and the piston rod 23 in a desired stroke position, this is already hydraulically secured by the use of the load-holding Senkbrems valves 150.1, 150.2. These are fluidly connected via the channel 48 and the channel 49 with the pressure medium working chambers 45 and 33 of the cylinder 21, the pressurization of the piston 22 on its side facing the piston rod end 44 and / or on its side facing the cylinder bottom 53 side 46th enable.

The load-holding lowering brake valves 150.1 and 150.2 thus already make it possible to secure 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 and for the transmission of tensile forces ,

In addition to the hydraulic securing by means of the load-holding lowering brake valves 150.1, 150.2, a mechanical securing of the locking cylinder 20 via the locking unit 56 is possible. This additional mechanical protection is particularly effective when leakage or failure or similar damage to the hydraulic system occurs. Because then engage the locking pin 40, 140 in the locking recesses 38, so that a positive and bidirectional locking of the spindle 35 and thus of the piston 22 is given in the given stroke position. This engagement or blocking position of the cylinder bolts 40, 140 is reached at 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 pressed by the mechanical force of the compression springs 39 against the previously rotating flange-shaped projection 65 until the respective locking pin 40.1 and 40.2 or 140.1 and 140.2 in the next possible locking recess 38 engages and thereby blocks the further rotational movement of the spindle 35.

The operation of the lock cylinder 20 will be described below using the circuit shown in FIG. 5.

In order to achieve, for example, a movement of the piston 22 and thus of the piston rod 23 relative to the cylinder 22 in the extension direction 28, the channel designated here with feed channel 86 is subjected to pressure medium, ie. H. it is supplied by means of a pump not shown in the figures through the flow channel 86, the pressure medium.

Up to a certain pressure, which depends on the spring characteristic of the spring 174.1 of the non-return valve 156.1, the pressure medium can not initially enter the channel 49 and thus not in the working space 33, but first passes through the first inlet 164 in the first channel part 169 of as a shuttle valve designed Rückströmsperrmittels 160, whereby the blocking means 171 opening a flow path through the discharge point 168 in the fluid channel 167 and from there via the outlet 166 in the switching channel 47 with substantially simultaneous closing of the second channel part 165 in the blocking position shown on the left in Figure 5 is moved.

At the same time, the channel 88.1 leading to the control connection 155 of the second load-holding lowering brake valve 150.2 is subjected to pressure medium. However, the pending pressure medium pressure still causes no opening of the second load-holding lowering valve 150.2. For 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 or 80.2. Consequently, the respective load-holding lowering brake means 150.1 and 150.2 opens only from a certain, prevailing at the respective control port 155.1 or 155.2 pressure medium pressure, depending on the set on the springs 80.1 and 80.2 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 respectively 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 cause movement of the piston 22 in the extension direction 28 and in the retraction 27.

The pressure medium then flows initially through the switching channel 47 to the pressure medium spaces in the region of the free ends 57 of the locking bolt 40 and causes them to be transferred from the locking position 41 shown in the direction 27 in its unlocked position. As soon as the sealing surfaces 97 of the locking bolts 40 bear against the counter-sealing surfaces 98, a further supply of pressure medium into the flow channel 86 causes a further increase in pressure, which causes the spring-loaded backflow barrier 156.1 to open. Then, the pressure medium can flow via the channel 49 into the first working chamber 49 to a movement of the piston 22nd and thus to cause the piston rod 23 in the extension direction 28.

At the same time leading to the control port 155.2 of the second load-holding lowering valve 150.2 channel 88.1 pressurized fluid of a corresponding pressure, whereby, depending on the currently acting in the flow channel 86 pressure, the load-holding Senkbrems valve 150.2 opens more or less wide, to allow a pressure medium flow from the second working space 45 via the channel 48 and the second load-holding lowering valve 150.2 in the direction of arrow shown in Figure 5 in the return passage 87.

The control takes place in such a way that the counterpressure set here by the load-holding lowering brake means 150.2 is controlled in the supply channel 86 as a function of the working pressure in the supply channel 86 causing the piston 22 to move along the cylinder 21, the counterpressure acting simultaneously decreasing as the working pressure increases, and preferably inversely proportional to the working pressure. In this way, it is always achieved during driving that the piston 22 is "clamped" in a force acting counter to its current direction of movement, thereby preventing an uncontrolled advance of the piston 22.

If the piston is then to be stopped in a desired stroke position, preferably both the flow channel 86 and the return channel 87 are pressure-relieved. This closes both the two return valves 156.1 and 156.2 as well as - due to the then occurring in the control channels 88.1 and 88.2 pressure relief - the two load-holding lowering valves 150.1 and 150.2, so that the pressure medium located in the working chambers 33 and 45 can not escape therefrom. The piston 22 is then clamped between the pressure columns present on its two sides 44 and 46 and fixed in its current stroke position.

A pressure relief at the channels 86 and 87 also has an effect in the switching channel 47, so that the locking bolts 40 can be transferred from their unlocking position into the locking position 41 shown in the figures by the spring forces of the springs 39 acting on them , Here, the located in the pressure medium spaces in front of the free locking ends 57 of the locking bolt 40 pressure fluid via the channel 47 and the shuttle valve 160 here flow back into the flow channel 86.

Depending on in which current rotational position, the spindle 35 and thus the locking recesses 38 are at a current holding stroke position of the piston 22, the locking bolts 40 then engage 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 annular shoulder 65, which are located between two immediately adjacent locking recesses 38. In such, any holding stroke position of the piston 22, it is not relevant in the normal case, whether the locking pin 40 or 140 engage in the locking recesses 38. Of course, something else applies in the event of leakage or damage in the pressure medium system. Then, the locking recesses 38 containing the rotates Approach still slightly further until the locking pins 40, 140 engage in the nearest locking recess 38. In the embodiments shown and described, however, it can only come to a very small stroke of the piston 22, which is in the millimeter range and which is completely sufficient in terms of safety.

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. are moved in the retraction 27, the return passage 87 is acted upon by pressure medium. Then, the blocking member 171 of the shuttle valve 160 is displaced by the inflowing pressure medium in the locking direction shown on the right in Figure 5, so that then the inflowing via the second inlet 165 in the second channel part 170 pressure medium via the discharge point 168 again in the fluid channel 167 and from there from flowing into the switching channel 47, in which case the first channel part 169 of the fluid channel 159 is shut off by the blocking means 171.

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

The operation of the locking cylinder 20 will now be described in more detail using the circuit shown in FIG. 6.

As already mentioned above, the mode of operation and function of the load-holding lowering brake means 150.1, 150.2 is the same as explained with reference to the example of the circuit according to FIG. 5, so that reference may be made to the above description parts.

If the locking cylinder 20 is acted upon via the flow channel 86 or the return channel 87 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, so that the locking bolt 140 against the spring force of the respective spring 39 from the locking position shown in FIG be pressed in the figures not shown unlocking position. At the same time there is a controlled leakage through the flow passage 54 of each locking bolt 40. Thus, 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 156.1 into the channel 49 and reach there into the first working chamber 33 and can pass through the first check valve 84 of the Rückströmsperrmittels 161 in the switching channel 47 at the same time. The pressure medium flows so then via the first inlet 164 of the Rückströmsperrmittels 161 in the first channel portion 169 of the fluid channel 159 and from there via the discharge point 168 in the branched fluid channel 167 and again from there into the switching channel 47. The second check valve 85 of the Rückströmsperrmittels 161 is closed, ie whose blocking member 172.2 obstructs the second channel part 170.

As soon as the locking bolts 140.1 and 140.2 are transferred to their unlocking position upon further supply of oil, the piston 22 can move in the extension direction 28 due to a simultaneous application of pressure medium on its side facing the cylinder bottom 53. As soon as the pressure medium flow in the flow channel 86 preferably drops to zero, both the two backflow shutters 156.1 and 156.2 and both load hold lowering brake valves 150.1 and 150.2 close. Almost at the same time, the locking bolts 140 are displaced by the springs 39 in the extension direction 28, so that they can latch 38 depending on the current position of the locking recesses 38, so that locked in the locking position 41, the spindle 35 and thus the piston 22 both hydraulically and mechanically are.

If, starting from the previously reached stroke position of the piston 22, this is moved back in the retraction direction, the return passage 87 can be subjected to pressure medium, ie the pressure medium can be supplied there. The pressure medium can then pass through the check valve 156.2 in the channel 48 and from there into the working chamber 45, so that the side facing the piston rod end side 44 of the piston 42 can be acted upon with pressure medium.

At the same time, a branched-off pressure medium flow from the return passage 87 via the second check valve 85 of the return flow blocking means 161 again reaches the switching passage 47, while the first check valve 84 is closed. This leads in the same way, as already explained above, to the fact that the locking bolt 140 automatically, d. H. be transferred to their unlocked without additional switching operation. Then, the piston 22 and thus the piston rod 23 moves in the retraction direction 27, wherein also, as explained above in connection with the circuit of Figure 5, in the working chamber 33, a back pressure acts, which is smaller than the working pressure in the working chamber 45, so that, in turn, no uncontrolled advance of the piston 22 in the retraction direction 27 can occur.

It is thus a characteristic feature of the method according to the circuit shown in Figure 6 that the pressure means for the purpose of retraction and / or for the purpose of extending the piston 22 at least one side 44 or 46 of the piston 22 and at the same time the locking pin 40 is supplied, wherein the Locking bolt 40 is transferred against the spring force of the spring 39 of the locking position 41 in the unlocked position, so that then the spindle 35 can rotate in a rotational direction 51 or in an opposite direction of rotation 52 with the result that the piston 22 according to the direction of rotation 51 or 52 is moved in the extension 28 or in the retraction 27.

The pressure medium flowing back through the channel 55 can be either via the check valve 82 or 82, depending on which of the channels 86 or 87 is pressurized be returned via the check valve 83 in the channel 86 or in the channel 87.

Claims (16)

1. Locking cylinder (20) with a cylinder (21) and a piston (22), which is movable parallel to the longitudinal axis (29) of the cylinder (21) with the help of a fluid pressure medium able to be fed to both sides of the piston (22) and which is provided with a piston thread (34), which with formation of a non-self-locking thread (37) is disposed in engagement with a spindle thread (36) of a spindle (35), which is rotatable about an axis (43) of rotation arranged parallel to the longitudinal axis (29) of the cylinder (21) and which has at least one outwardly open locking recess (38), in which at least one locking body (42, 142) loaded by means of spring force of a spring can engage, the locking body being secured against rotation about the axis (43) of rotation of the spindle (35) and mounted on a head (31) of the cylinder (21) to be axially displaceable parallel to the axis (32) of rotation of the spindle (35) and being transferable with the help of the spring force of the spring (39) to a locking setting (41) in which it engages in the locking recess (38) of the spindle (35) with formation of a mechanically positive and bidirectional locking of the spindle (35) so that rotation of the spindle (35) about its axis (43) of rotation is then blocked in opposite rotational directions, and wherein the locking body (42, 142) is transferable with the help of a fluid working medium against the spring force of the spring (35) from the locking setting (41) to an unlocking setting in which the spindle (35) is rotatable about its axis (43) of rotation so as to enable movement of the piston (22) longitudinally of the cylinder (21), characterised in that several locking bodies (42, 142) are formed as separately movable locking pins (40, 140).
2. Locking cylinder according to claim 1, characterised in that the locking pins (40, 140) are arranged to be movable independently of one another.
3. Locking cylinder according to claim 1 or 2, characterised in that two separate locking pins (40, 40.1, 40.2; 140, 140.1, 140.2) are provided.
4. Locking cylinder according to one of claims 1 to 3, characterised in that the locking pins (40, 140) are each mounted with a small play in a respective bearing recess (75), which is open towards the side of the locking recesses (38), of the head (31) of the cylinder (21).
5. Locking cylinder according to one of claims 1 to 4, characterised in that the locking pins (40, 140) are cylinder pins (69).
6. Locking cylinder according to one of claims 1 to 5, characterised in that the locking pins (40, 140) each have a conical outer contour (50) at their free locking ends (73).
7. Locking cylinder according to claim 5 or 6, characterised in that the cylinder pins (69) are each mounted with a small play in a bearing recess (75) having a cylindrical internal contour (89).
8. Locking cylinder according to one of claims 1 to 7, characterised in that the locking pins (40, 140) each have a recess (92) which is outwardly open at its end (56) associated with the respective spring (39) and in which the respective spring (39), which is formed as a compression spring, is received by a spring section (93), the spring being supported there by one of its ends (95) in each instance against an inner surface (94) of the respective locking pin (40, 140), wherein its other end (96) is supported against the head (31) of the cylinder.
9. Locking cylinder according to one of claims 1 to 8, characterised in that the locking pins (40, 140) each have an encircling sealing surface (97) which faces in the unlocking direction (27) of the respective locking pin (40, 140) and which in the unlocking setting of the respective locking pin (40, 140) and under the pressure forces then exerted by the working medium in the unlocking setting sealingly bears against an encircling counter-sealing surface (98) of the head (31) of the cylinder (21).
10. Locking cylinder according to claim 9, characterised in that the sealing surface (97) at the same time forms at abutment surface for limitation of an unlocking stroke of the respective locking pin (40, 140).
11. Locking cylinder according to claim 9 or 10, characterised in that the sealing surface (97) is arranged in the region of the end (59), which is associated with the spring (39), of the locking pin (40, 140).
12. Locking cylinder according to claim 11, characterised in that the sealing surface (97) is arranged at an annular end edge (39) of the locking pin (40, 140) at the end (59) thereof associated with the spring (39).
13. Locking cylinder according to one of claims 9 to 12, characterised in that the locking pins (40, 140) are formed to be closed in cross-section so that when the sealing surface (97) of the respective locking pin (40, 140) sealingly bears against the respective counter-sealing surface (98) leakage of the working medium along the respective locking pin (40, 140) is prevented.
14. Locking cylinder according to one of claims 1 to 12, characterised in that the locking pins (140) each have a passage channel (54) which in the locking setting (41) opens in the region of the locking recess (38) and is connected at the other end with a channel (55) so that the fluid working medium can flow out of the respective locking recess (38) into the channel (55) on movement of the respective locking pin (140) from its unlocking setting to its locking setting (41).
15. Locking cylinder according to claim 14, characterised in that the respective passage channel (54) has at its end (57), which is associated with the locking recess (38), of the respective locking pin (140) a throughflow cross-section which is very much smaller than an effective area (58) of the respective locking pin (140) at which the fluid working medium can engage in order to transfer the respective locking pin (140) to its unlocking setting.
16. Locking cylinder according to one of claims 14 and 15, characterised in that the respective passage channel (54) in the respective locking pin (140) laterally widens with formation of a supporting and contact step (60) for the respective spring (29), which is constructed as a compression spring.

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