JPH05196006A - Hydraulic controller - Google Patents

Abstract

PURPOSE: To prevent post-movement of a double-acting cylinder by connecting each action conduit extending from two rooms of the double-acting cylinder with a control pressure conduit with an attenuation throttle installed midway, and connecting a conduit loop installed with a valve to the control pressure conduit detouring around the attenuation throttle. CONSTITUTION: The double-acting hydraulic cylinder 1 of a track crane is supplied with pressure oil from a pressure supply source P through a control valve C and action conduits 4, 5. A load-retaining valve H to help hold a load F at e.g. the zero position of the control valve C is installed midway along the action conduit 4 connected to the piston head side room 2 of the cylinder 1. The adjustable attenuation throttle 13 to attenuate pressure fluctuation in downward movement of the load F or controlled open-close movement of a valve 6 is installed midway along the control pressure conduit 12 which connects two action conduits 4, 5. Here, a conduit loop 14 with a valve 15 which can be positioned at the cutoff position by the pressure of a spare control conduit 17 is furnished detouring around the attenuation throttle 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic control device of the type described in the preamble of claim 1.

[0002]

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION 800
0 Munich 80, published 7 June 1986, edited by Heilmeier and Weinline 7100
In hydraulic control systems, as is known from pages 1 and 2, the damping throttle provides a controlled closing movement or a controlled opening and closing movement of the load holding valve in order to damp the pressure fluctuations of the device and thus the vibrations of the load. Must be dampened. The function of the load retention valve is to have an undesired or unacceptable after-running of the hydraulic consumer under load after the hydraulic consumer has been shut down.
g) is to be prevented. A control device of this type equipped with a damping throttle can be used for all types of lifting with a change in the indication of the load direction, for example in lifting or extension cylinders of cranes, in particular vehicle cranes, in rotary piston cylinders or rack / pinion pivot cylinders. It is preferably used in the upper and pivoting means, such as in cable-winches or pivot mechanism drive means, when the oscillatory movement of the hydraulic consumer must be expected. The damping throttle is set so that in the case of an operatively warm pressure medium, when the load holding valve is opened and the hydraulic consumer is moved under load, it damps pressure fluctuations optimally. Within the load holding valve there is a working clearance associated with the movement of the relatively small pressure medium volume in the control pressure conduit. These volumes pass through the damping throttle and create a damping effect within the device.
The damping throttle provides a desired rapid closing movement of the load holding valve for stopping or positioning the load due to the setting of the selectively tight damping throttle to achieve optimum damping and / or in the case of cold pressure medium. May delay. As a result, the hydraulic consumer consumes harmful or dangerous after-motion after a stop under load.
run).

In this type of hydraulic control device, as is known from DE 3733740 A1, the load lowering valve consists of two throttle gaps arranged in parallel inside the control pressure conduit of the load lowering valve with the aid of laminar flow. Controlled through. The two throttle gaps are matched to each other in terms of their linear characteristic so that their summing characteristic substantially follows the desired characteristic curve in the operating range. Two
Throttle gaps change their gap height in response to temperature. A vibration damping action independent of the temperature of the pressure medium is thus aimed at. This principle is also suitable for load holding valves. The gap height of the two throttle gaps designed for optimum damping in the case of a cold pressure medium cannot exclude after-running of the hydraulic consumer when a load holding valve is present.

This type of hydraulic control device is often integrated in a hydraulic system with a safety shut-off function. This is a hydraulic consumer, or a component that is moved by it,
Is monitored for load limits, load moment limits or motion limits that must not be exceeded. The limit pressure or limit position sensor produces an electrical signal that opens a solenoid valve in the control circuit. This valve reduces the opening pressure for the control means of the control valve of the hydraulic consumer or for the main control means of the hydraulic system. Further movement of the hydraulic consumer above this critical limit should be prevented by no longer delivering effective pressure in this direction of movement or by limiting the amount of effective pressure medium. However, it often happens that the sensor responds to this safety limit only in a precise manner, or at best within a relatively narrow predetermined tolerance range. If the hydraulic consumer exceeds the tolerance range despite the response from the sensor, e.g. due to the backward movement of the hydraulic consumer under load, the sensor no longer responds and the hydraulic consumer is within the critical range. Can be controlled without any restrictions. In cranes, for example, this is particularly dangerous for vent cylinders or horizontal pivot cylinders, and above all, as has been found in practice, strong damping effects in the case of cold pressure media or by standard installed damping devices. See below.

The object of the invention is a hydraulic control device of the type mentioned above, in which undesired back movements of the hydraulic consuming device are eliminated under load despite a damping action for normal operation. Or to improve the hydraulic control device by means of a safety shut-off means with regard to the reliability of its safety function even under adverse conditions.

[0006]

According to the invention, said object is achieved by the features indicated in the characterizing part of claim 1.

If the hydraulic consumer, or rather the load, should be lowered by releasing the pressure medium from the working conduit containing the load holding valve, the opening pressure is delivered in the control pressure conduit and the load holding. The valve is opened in a controlled manner. The valve arranged in the conduit loop maintains its closed position; the pressure medium passes through the damping throttle and is damped. Whenever the hydraulic consumer is to be shut down, the control pressure conduit is depressurized until the load holding valve closes in a controlled manner and holds the load. In the case of cold and therefore viscous pressure media, the valve responds to the resulting pressure differential and assumes its through position in order to ensure a satisfactory and rapid closing of the load holding valve. The pressure medium bypasses the damping throttle. Similarly, in the case of a selectively throttled damping throttle to achieve the desired damping action and in the presence of an operationally warm pressure medium, the valve must be deactivated by the hydraulic consumer and The load must be held and responds whenever the damping throttle will prevent such effects. The responsiveness of the valve is such that under adverse operating conditions any after-running of the hydraulic consumer is prevented and when the damping throttle nevertheless requires damping action, for example the load is lowered. When is always adjusted to perform such an action. The hydraulic controller may automatically disable the damping throttle whenever there is an operating condition that is critical with respect to the movement of the hydraulic consumer along with the valve. This provides the benefits of a damping throttle that can be optimally adjusted for damping and the quick response and load retention benefits of the load retention valve in operating conditions where the damping throttle interferes with the controlled closure of the load retention valve. If a safe cut-off is ensured in the hydraulic system including the hydraulic control device, the hydraulic consumer cannot exceed the safety limit or pass the safety tolerance range even under adverse conditions.

In an embodiment according to claim 2, the second pressure difference at the valve is such that when the load holding valve has almost reached its load holding position and only a small amount of effective pressure medium has passed through it. Is adjusted to allow the pressure throttle to regain its maximum effect. The residual closing lift of the load-holding valve can be monitored again by means of a damping throttle, which can carry out an independent damping action when pressure oscillations occur.

In the embodiment of claim 3, the pressure in the control pressure conduit initially maintains the valve in the closed position when the load holding valve is open. This pressure overcomes the force permanently acting on the valve. Even with non-extreme pressure fluctuations, the valve element remains in the shut-off position, so that the damping throttle damps the load-holding valve play and pressure oscillations in the hydraulic system. If the pressure in the pressure control conduit is reduced by the damping throttle to such an extent that the permanently acting force moves the valve in a controlled manner to the through position.
The pressure reduction that allows a precise and controlled closing movement of the load holding valve is ensured by the pressure medium flowing through the valve.
Due to the pressure medium flowing through the damping throttle at any flow rate, the valve will only move to the through position under normal operation if any back movement of the hydraulic consumer must be of any concern. In contrast, when excessive pressure fluctuations are present, the valve may also be moved to the position for a short time in a controlled manner, thus supporting the damping action of the damping throttle by reducing the pressure peaks. But a permanent force will immediately return it to the blocking position.

The embodiment according to claim 4 has a simple structure. The pressure difference between the opening pressure and the elastic force acting on the valve element is passed through the damping throttle at an arbitrary flow rate. The responsiveness of the valve is adjusted by the choice of this pressure difference, so that the damping throttle operates mainly with non-extreme pressure fluctuations in the system, while the damping throttle allows the reliable stop of the hydraulic consumer to be under load. And, when needed in the presence of cold pressure medium, it is automatically ignored to the required limit.

The features of the embodiment of claim 5 are also important because the sliding valve does not leak oil without requiring any significant structural work and operates in a relatively temperature independent manner. is there.

In an embodiment of claim 6, the biased closed check valve also works under load, in the rising pressure window during movement of the hydraulic consumer, ie the pressure difference in the damping throttle causes the check valve to act. At the same time as it becomes larger than the acting permanent force, the pressure medium is such that the permanent force must close the closing check valve again and the residual pressure medium must flow through the damping throttle from the open side of the load holding valve. Flow off through the damping throttle until the pressure differential decreases. The desired effect here is to substantially stop the hydraulic consumer before the load-holding valve closes rapidly in a forceful motion and before the load-holding valve moves to its closed end position in a subsequent damped residual lift motion, The passage in the working conduit is already somewhat restricted in the working conduit. Thus, not only are pressure fluctuations suppressed or dampened, but the load holding valve is also very reliable in a controlled manner (especially in the case of safe shut-off operation) and from operating conditions (including cold pressure media). Independently and quickly beyond the safety limit or through the safety tolerance range, the movement of the hydraulic consumer closes so fast that no movement occurs.

It has been found that the embodiment of claim 7 is practically useful. With such an adjustment, the rearward movement of the hydraulic consumer under load is prevented even in the case of tight settings of the cold pressure medium and the damping throttle.

In the embodiment of claim 8, a relatively strongly biased closing check valve allows a substantially unobstructed action of the damping throttle. Because it is only effective if there is an unacceptable risk of movement of the hydraulic consumer, and it is immediately switched off again when this risk is eliminated after a strong controlled closing movement of the load holding valve. Because it does.

Another advantageous embodiment emerges from claim 9. Especially in vehicle cranes, strong vibrations of load can be practically observed. These vibrations cause long lasting pressure fluctuations in the hydraulic system and make the crane more difficult to operate. Therefore, the damping effect of the motion damping throttle is no longer satisfactory. Due to the bypass conduit and the obstructing throttle passage arranged therein and the throttle passage cooperating with it in the control pressure conduit, an additional hydraulic damping device very effectively and quickly damps the load holding for damping the pressure fluctuations. Incorporated into the control circuit of the valve, the amount of pressure medium flowing off through the bypass conduit interferes with the amplitude of the pressure oscillations to the extent that pressure fluctuations are soon dampened. The inclusion of different pressures (pressures prevailing then in the control circuit of the load-holding valve) into the pre-control means of the valve subjected to a permanent force leads to critical operating conditions (cold pressure medium and / or tightly set movements). It provides the benefit of a load retention valve that is closed immediately even under damping throttle).

The permanently acting force may be relatively small in the embodiment of claim 10 because it is supported by the pressure in the bypass conduit. This improves the response characteristics of the valve. Since the valve participates in damping the pressure fluctuations, this has the additional benefit that the dimensional difference between the throttle passage and the obstructing throttle passage can be made very small, so that the amount of pressure medium flowing out through the bypass conduit is , Can be kept as small as desired.

The features of claim 11 are also important. The volume flow required for valve damping and pre-control is
In fact, it must be possible to flow off through the bypass conduit in order to contribute to the damping action.
If the control valve, which establishes the connection between the tank and the two working conduits or the tank and the working conduit with the load holding valve in the zero position, is integrated in the hydraulic control device, the bypass conduit is preferred. Is connected to said conduit.
Alternatively, the bypass conduit can also be directly connected to the tank. In such cases, a directional control valve with a blocked zero position may also be used. And also, a directional control valve with an inflow controller can be used because of its effective damping action, but it usually has a rather long transient response, which is itself adventurous for oscillating controllers. Is.

Furthermore, the embodiment of claim 12 is such that the bypass check valve for controlled opening bypasses the damping throttle for the immediate controlled opening of the load holding valve desired for certain applications. It is convenient because it enables it. In the case of pressure oscillations during the movement of the hydraulic consumer, this check valve is kept closed by the pressure in the control pressure conduit at any flow rate, so that the control pressure medium must flow through the damping throttle. I won't.

An embodiment which is structurally simple is described in claim 13. The check valve is integrated in the valve and ensures a controlled opening of the load holding valve without causing delay.

The embodiment of claim 14 is characterized by a particularly effective damping of pressure fluctuations in the hydraulic system.
The operation of the closed check valve is advantageously influenced by the pressure accumulator.

Furthermore, the embodiment of claim 15 is advantageous. A check valve provided at this point prevents the control pressure medium from flowing off to the other working conduit, or
Prevents pressure fluctuations in the control pressure circuit from propagating into the other working conduit. Furthermore, the check valve forces the pressure medium from the pressure accumulator to flow off through the bypass conduit for effective damping action.

The embodiment of claim 16 is that the simple safety shut-off device cannot even be deceived under adverse operating conditions such as a strong damping action by a cold pressure medium or a tightly set damping throttle, and the load holding valve is It has the particular importance of being independent as it closes as desired without any discernible back movement. At the safety shut-off point, the closed check valve may be biased less strongly, while within the safety shut-off tolerance range it may be biased to a greater extent. The reliability of the safety shut-off action is also ensured under completely right conditions for normal operation, which are particularly disadvantageous for the safety shut-off action.

The embodiment of claim 17 provides a simple construction of the safety shut-off device, since each sensor, just like the relief valve, only needs a power supply means which can be easily accommodated. The relief valve has small dimensions and can be integrated in the directional control valve or control means without any problems.

In all of the embodiments described above, the valve as well as the additional components can be mounted directly in the block of the load holding valve. However, by mounting the unit on the load-holding valve as a retrofit unit, or placing it elsewhere in the control circuit of the load-holding valve and modifying a previously operating or previously designed control device, It can also be renovated.

In the following, embodiments of the inventive subject matter will be described with reference to the accompanying drawings.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A load arm carrying a load F, for example, a vent cylinder of a vehicle crane.
r), a hydraulic consumer V for exercising, for example a double-acting hydraulic cylinder, can be found in a hydraulic controller S as shown in FIG. A double-acting hydraulic cylinder having two chambers 2, 3 separated by a piston is supplied with pressure medium from a pressure source P from a tank T. A control valve C is installed to control the hydraulic power consumption device V.
In the illustrated embodiment, this is the reduced pressure zero position (reli).
4 / with an embedded zero position)
It is a three-way control slide. The chambers 2, 3 of the hydraulic power consumption device V are connected to the control valve C via working conduits 4, 5. When pressure acts on the working conduit 4, the load F is lifted and the pressure medium is discharged through the other working conduit 5. When the pressure acts on the other working conduit 5, the hydraulic consumer V is moved (lowered) under the load F and the pressure medium is discharged through the working conduit 4. One of the working conduits 4 has a load holding valve H arranged therein, which serves to hold the load F, for example in the zero position of the control valve C. The load holding valve H is provided with a valve 6 which is continuously adjustable between a passing position and a closing position with respect to the control valve C according to a conventional manner and has a valve member 7 having an open position (not shown). The valve member 7 has a spring 7'in the closed position (not shown).
Loaded by Furthermore, the pre-control pressure transmitted via the control line 9 acts on the side of the control valve C in the closing direction. In the open position, in contrast, the pre-control pressure acts in the control line 8 branching from the action line 4 between the valve 6 and the hydraulic consumer V. Furthermore, a control pressure conduit 12 is provided. The pressure in the control pressure conduit acts on the valve member 7 in the opening direction. The control pressure conduit 12 branches from the working conduit 5 in this embodiment. However, it is also possible to supply pressure to the control pressure conduit 12 from an independent pressure source or pressure control device.

The load holding valve H is bypassed (for lifting purposes) by a bypass line 10 having a check valve 11 which opens in the direction of the hydraulic consumer V.

Pressure fluctuations during the downward movement of the load F and, in the present embodiment, an adjustable damping throttle 13 which damps the controlled opening and closing movement of the valve 6 is included in the control pressure conduit 12. The conduit loop 14 is a control pressure conduit 12
Bypass the damping throttle 13 provided in the. The conduit loop 14 is arranged in FIGS. 1 to 5 with a valve having a valve element 16 and a reversible 2/2 way slide valve between a passing position a and a closing position b. Valve element 16
Is acted upon by a permanent force f of the spring 18 which can be adjusted freely towards the threaded position a. In contrast, valve element 1
6 is acted upon by the pressure in the precontrol conduit 17 towards the shut-off position b. The pre-control conduit 17 branches off from the conduit loop 14 between the valve 15 and the other working conduit 5.

The force f is a little less than the force acting on the valve element 16 through the (open) pressure in the precontrol conduit 17.

To lower the load F, the working conduit 5 is acted upon by the pressure by the control valve C. Since the check valve 11 closes, the valve 6 must be opened in a controlled manner. This is achieved through the control pressure conduit 12 and the damping throttle 13. The pressure in the control pressure conduit 12 holds the valve 15 in the closed position via the pre-control conduit 17, so that the pressure medium passes across the controlled opening actuation damping throttle 13. If pressure fluctuations are later observed in the hydraulic system during the downward movement, at least in the case of non-extreme pressure fluctuations, the valve 15 remains in its closed position. Effective play of valve 6 (for example, several 1 / 10m
During the range m), the pressure medium is damped by the damping throttle 13.

If the load F should be stopped, then
The pressure in the other working conduit 5, and thus the control pressure conduit 12, is relieved. If the pressure at the valve member 7 cannot be relieved quickly enough due to the controlled closing of said valve member via the damping throttle 13, the spring 18 bypasses the damping throttle 13 via the conduit loop 14. The valve element 16 into the threading position a, so that the valve closes rapidly. This prevents any after-running of the hydraulic consumer V. Valve 15
Whenever the damping throttle 13 delays a controlled closing movement due to the viscosity of the cold pressure medium, or whenever the damping throttle 13 is set very tight for sufficient damping action, validate. Furthermore, when there is excessive pressure fluctuation in the control pressure conduit 12, the valve 15 can be switched to the short passageway to participate in the damping action and pass the pressure peak. Even before the pressure in the control pressure conduit 12 is completely relieved, the spring 18 moves the valve 15 to the closed position. The residual pressure is released through the damping throttle 13. The valve 15 performs the auxiliary closing function in the same way as with the rising pressure window.

The hydraulic control system S shown in FIG. 2 is an additional conduit loop 19 of the control pressure conduit 12 which has a non-return valve 20 opening towards the valve 6 in a controlled manner between the controlled opening of the valve 6. It differs from the embodiment shown in FIG. 1 by having one arranged to prevent any delay. In the case of pressure fluctuations during the downward movement, the check valve 20 is held in the closed position, so that the momentum of the control pressure medium passes through the damping throttle 13. The other functions of the hydraulic control device shown in FIG. 2 are the same as those shown in FIG.

In the embodiment shown in FIG. 3, the check valve 20 is structurally integrated with the valve 15 'and its valve element 16'. The function is the same as that in the embodiment shown in FIG.

The hydraulic control S according to FIG. 4 differs from the embodiment of FIG. 2 by having an additional damping device X for pressure fluctuations in the system. The damping device X includes a throttle passage D ₁ in the control pressure conduit 12 and a control pressure conduit 1
Bifurcate at 2 to 21 and block throttle passage D
_And a bypass conduit 22 having _two . The disturbing throttle passage D ₂ is larger than the throttle passage D ₁ . The bypass conduit 22 is connected (at 23) to the working conduit 4 or is directly connected to the tank T, as indicated by the dashed line 24, so that the working conduit 5 and thus the control pressure conduit 12 are under pressure. At this time, the pressure medium steadily flows out through the bypass conduit 22. The passages D ₁ and D ₂ connected in series have an additional damping effect on the pressure fluctuations as the control pressure medium flows away.

In the opening direction, the damping throttle 13 is bypassed by the check valve 20. Conduit loop 14
Is arranged with its valve element 16 ", which ensures a rapid closing of the valve 6 under adverse operating conditions (cold pressure medium and / or tight regulation of the damping throttle 13). Valve element 16 "is a load toward the through position a by the pressure in the spring 18 and the pilot control conduit 26 having a permanent force. Downstream of disturbance throttle passage D _2, the pilot control conduit 26 is a bypass conduit 22 from the control pressure conduit 12 to the shut-off position b by means of the predominant pressure present between the connection point of the bypass conduit 22 and the damping throttle 13. Is pressed. The force f regulated by the spring 18 may be relatively small in this embodiment because the spring 18 is supported by the pressure in the pre-control conduit 26. At the opening pressure of 20 bar required in the valve 6, the setting of the spring 18 to a pressure value of 15 bar will result in any backlash in the case of a cold pressure medium and / or an overly tightly regulated motion damping throttle 13 ( It is sufficient to ensure a rapid closing of the valve 6 without causing any after-running. Valve 1
Since 5 ″ supports damping of pressure fluctuations, the obstructing throttle passage D ₂ need only be slightly larger than the throttle passage D ₁ so that the amount of pressure medium flowing off through the bypass conduit 22 is in the desired manner. Is kept small at.

The function of the hydraulic control device S according to FIG. 4 is substantially the same as that in FIG.

In the modified embodiment shown in FIG. 5, the check valve 20 as shown in FIG. 4 is structurally integrated with the valve element 16 "of the valve 15"". The pressure pre-control of valve 15 "" is performed in the same manner as that in FIG.

The valves 15, 15 ', 15 ", 15"' do not necessarily have to be sliding valves, but sliding valves have the advantage of virtually oil-free operation. The desired function may also be achieved by a seat valve or a biased openable check valve.

Furthermore, the pressure medium is, for example, cold, or when the pressure prevailing on the open side of the valve 6 rises excessively, either because of a delayed pressure reduction or because the pressure is not reduced sufficiently quickly. Can be actuated by a magnet at any time and operated by a remote control via a thermostat or a pressure control device 15,1
It is also possible to configure 5 ', 15 ", 15"'.

In the embodiment shown in FIG. 6, the hydraulic control device S has a damping throttle 13 in the direction away from the valve 6.
It has a closed check valve as a valve 15 ^IV for bypassing the valve.
The check valve blocking element 16 ^IV is biased towards the seat 28 by a bias-adjustable spring 18. The closing check valve causes the permanent force f of the spring 18 to flow away from the valve 6.
Open against. The spring 18 is set to a bias value that is slightly less than the value of the force acting on the blocking element 16 ^IV through the opening pressure. At an opening pressure of about 40 bar, the spring 18
Force of at least 15 bar and is preferably about 25 bar. The function of the hydraulic control device S is equivalent to the function of the embodiment shown in FIG. But also the second
It is also possible to dispense with the check valve 20 in the conduit loop 19 of FIG. The functioning of the hydraulic control device S according to FIG. 6 is therefore equivalent to the functioning of the embodiment shown in FIG. 1, except that the damping device X is additionally provided in FIG.

Unlike the embodiment shown in FIG. 4, the bypass conduit 22 of the damping device X is connected to a return conduit 24 which is directly connected to the tank T. One working conduit 4 is here also connected to the return conduit 24 via a relief valve 27. Furthermore, a filter 29 is arranged in the control pressure conduit 2. Furthermore, a non-return valve 32, which shuts off towards the other working conduit 5, is arranged on the side of the control pressure conduit 12 facing the other working conduit 5 (not shown). Furthermore, the pressure accumulator 31 is additionally connected at the connection point 21 via the conduit 32. The damping device X including the accumulator 31 can also be omitted. Furthermore, it is possible to provide a damping device X that does not have the pressure accumulator 31.

If the control pressure conduit 12 for closing the load holding valve H is not acted upon by pressure, the check valve 32 is closed. The pressure in the control pressure conduit 12 is released through the bypass conduit 22 into the return conduit 24. If the pressure difference increases at the damping throttle 13 to such an extent that the controlled closing movement of the valve 6 is delayed due to, for example, a cold pressure medium or a tight adjustment of the damping throttle 13, the force f of the spring 18 is overcome and overcome. The check valve for control closure is opened. The valve element 7 of the valve 6 of the load holding valve H is
It performs a strong lift in the closing direction until it is almost in the closed end position. The load and hydraulic consuming device is stopped. If any, a negligible amount of working pressure medium now only flows off the valve 6. The spring 18 acts on the blocking element 16 ^IV , the pressure difference dampening the throttle 13
After being correspondingly reduced in, contact with the seat 28 again.
The control pressure medium is used to lift the remaining lift of the valve element 7.
It is propelled through the damping throttle 13 through t).
The controlled closing movement of the valve 6 takes place in two stages which are continuous with one another in a coordinated manner, the first longer stage being caused by the closing check valve and the second shorter stage being caused by the damping throttle 13. No appreciable after-running of the hydraulic consumer is observed in this case. The response characteristic of the load holding valve H is required for damping and adjusted for optimal damping so that the damping throttle is not overridden under adverse operating conditions, possibly causing back movement. It can be adjusted more or less. This is particularly advantageous, for example, when back movement of the hydraulic consumer or of the components actuated by it in the safety circuit is to be prevented or only allowed to a precisely determined limit.

FIG. 7 illustrates the incorporation of a hydraulic control S in a hydraulic system K having a safety shut-off device A, for example a crane. The safety shut-off device A prevents further movement of the hydraulic consumer device V at the load limit, the load moment limit or the limit of movement in the direction in which such limit is reached. The hydraulic power consumption device V in FIG. 7 is, for example, a vent cylinder of a crane. The reference point 33, which is outlined in the hydraulic consumer V, must not pass beyond the limit indicated by the shaded area 34. Instead of motion limits, pressure or moment limits can also be monitored. The sensor 43 senses the reference point 33 and generates a signal as soon as the reference point 33 reaches the shadow area 34. If the line-shadow area 34 is again separated by the reference point 33 in one direction or the other, no signal is generated anymore.

The working conduits 4 and 5 are connected to a control valve C which is constructed as a directional control valve and is supplied with pressure medium by a pump P and at the same time is connected to a tank T.
A control means, for example in the form of a suction controller Z, which supplies the control valve C with the amount of pressure medium required to completely control the hydraulic consumer V in response to the load pressure, is arranged on the suction side of the control valve C. It For this purpose, the control means Z is actuated in the closing direction by the pressure upstream of the control valve C through the preliminary control conduit 41, while it is controlled by the control conduit 37.
Through the load pressure in the working conduit 5 and in the opening direction by the control spring 42. This is the conventional pressure balance principle.

Instead of the suction controller, the control means Z
Is also a main controller that regulates the suction pressure or flow rate in the common supply conduit in response to the maximum demand or priority of the selected hydraulic consumers when there are multiple hydraulic consumers supplied by the same pump P. Can also be configured by.

Located in the control conduit 37 is a relief valve 36, which is preferably configured as a solenoid valve with a solenoid 38 and a shut-off spring 39 for the valve element 40.
Solenoid 38 receives a signal from sensor 43 into conduit 35 and depressurizes control conduit 37 at the same time reference point 33 enters shaded area 34. The control means Z interrupt the further supply to the control valve C. The pressure in the working conduit 5 is no longer increased. When the safety shut-off device A responds, the load-holding valve H shown on the left side of FIG. 6 is thus such that the hydraulic consumer device V is not allowed to make any movement while its reference point 33 passes through the shaded area 34. It must be closed quickly. The valve 15 ^IV of the left load holding valve H is adjusted by its spring 18 so that it guarantees a rapid closing of the load holding valve H which is coordinated with the shaded area 34.

The load holding valve H shown on the right side of FIG. 7 serves for load holding purposes in other directions of movement of the hydraulic consumer V. This is not shown in FIG. 7, but the direction of movement of the hydraulic consumer V can also be monitored by the safety shut-off device A. In this case, one working conduit 4 also has a control means Z.
Must be in pressure control communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a hydraulic control device in a load holding position.

FIG. 2 is a diagram showing a modified embodiment of the hydraulic control device in the load holding position.

FIG. 3 is a diagram showing a modification of the details of FIG.

FIG. 4 is a diagram showing another embodiment of the hydraulic control device.

FIG. 5 is a diagram showing a modification of the details of FIG.

FIG. 6 is a diagram showing yet another embodiment of the hydraulic control device.

FIG. 7 is a diagram showing a hydraulic control device having a safety cutoff device.

[Explanation of symbols]

 S hydraulic control device V hydraulic consumption device H load holding valve C control valve X damping device 4 working conduit 5 working conduit 12 control pressure conduit 13 damping throttle 14 conduit loop 15 valve 16 valve element 17 preliminary control conduit 18 spring 19 conduit loop 20 reverse Stop valve 22 Bypass conduit 31 Accumulator 32 Check valve 36 Relief valve 43 Sensor

Claims (17)

[Claims] 1. A double-acting hydraulic power consumption device (V), comprising:
A hydraulic power consumption device (V) secured in at least one direction of action by a load holding valve (H, H ₁ ) which can be actuated by pressure through two working conduits (4,5) and can be hydraulically opened and closed in a controlled manner. ), A control pressure conduit (12) which is connected to the control connection of the load holding valve (H) and can be selectively actuated, and the control pressure conduit (1
In a hydraulic control device (S) having a damping throttle (13) located at 2), the control pressure conduit (12) is in parallel with the damping throttle (13) on the valve (15, 1).
5 ', 15 ", 15"', 15 ^IV ) placed on it,
During a controlled closure of the load holding valve (H), the valve is responsive to pressure from a shut-off position (b) to a through position (a), a predetermined viscosity dependence and / or in the damping throttle (13). Alternatively, the hydraulic control device is capable of automatically performing reverse rotation with a first pressure difference depending on adjustment. 2. The hydraulic control device according to claim 1, wherein
The valve (15,15 ', 15 ", 15"", 15 ^IV )
Is capable of automatically reversing from the through position (a) to the shut-off position (b) in response to a pressure with a second predetermined pressure difference smaller than the first pressure difference. Hydraulic control device. 3. A hydraulic control device according to either claim 1 or claim 2, wherein the control pressure conduit (12) has a conduit loop (14) arranged therein and bypassing the damping throttle (13) and the through loop (14). Said valve (15,15 ', 15 ", 15) having valve elements (16,16', 16", 16 "') adapted to be moved between position (a) and said shut-off position (b); ″ ″) Arranged on it, and said valve elements (16, 16 ′, 16 ″,
16 ″ ′) on the side of the damping throttle facing away from the load holding valve (H), the control pressure conduit (1
2) is adjusted to a value less than the value of the opening pressure force of the load holding valve (H) acting towards its shut-off position (b) by the opening pressure prevailing in it and acting on the valve element. Its passing position (a) due to permanent force (f)
And a hydraulic control device. 4. The hydraulic control device according to claim 3,
For the valve element (16, 16 ', 16 ", 16"') being loaded by a spring (18), the spring (18) for a force value corresponding to about 15 bar on the valve element. Is adjusted by an opening pressure of, for example, 20 bar. 5. The hydraulic control device according to claim 1, wherein the valve (15, 1)
5 ', 15 ", 15"' are said valve elements (16, 1)
6 ', 16 ", 16"") is a sliding valve having a piston slide forming a hydraulic control device. 6. A hydraulic control device according to claim 1, wherein the control pressure conduit (12) has a conduit loop (14) arranged therein and bypasses the damping throttle (13) and is closed. A valve (15 ^IV ) configured as a stop valve, the blocking element (16 ^IV ) adapted to be moved between the through position and the shut-off position having a flow direction away from the load holding valve (H). )
With a blocking element (16 ^IV ) having a permanent force (f), eg an adjustable spring (1).
8) which is set to a value less than the force value of the opening pressure of the load holding valve (H) acting on the blocking element (16 ^IV ), elastically biasing towards its shut-off position. And a hydraulic control device. 7. The hydraulic control device according to claim 3 or 6, wherein the permanent force (f) opens the load holding valve, and the damping throttle (13) and the load holding valve (H). Between 10% and 50% of the value of the opening pressure force required in the control pressure conduit (12) between
A hydraulic control device characterized by being limited to a small value. 8. A hydraulic control device according to claim 6,
The spring (18) with an opening pressure of 35 to 40 bar.
Is set to a value of force corresponding to about 25 bar in said blocking element (16 ^IV ). 9. The hydraulic control device according to claim 1, wherein the throttle passage (D
₁ ) on the side of the damping throttle (13) facing away from the load holding valve (H), the control pressure conduit (1)
2) and a bypass conduit (22) is provided in the throttle passage (D ₁ ) and the damping throttle (1).
3) A hydraulic control device branching from the control pressure conduit (12) and having an obstructing throttle passage (D ₂ ) larger than the throttle passage (D ₁ ). 10. A hydraulic control device according to any one of claims 1 to 5 and claim 9, wherein the valve element (16 ″, 1) of the valve (15 ″, 15 ″ ″).
6 ″ ′ is the control pressure conduit (1) between the damping throttle (13) and the throttle passage (D ₁ ).
2) acted towards its shut-off position (b) by the pressure prevailing in 2) and prevailing in said bypass conduit (22) by said permanent force (f) and downstream of said blocking throttle passage (D ₂ ). A hydraulic control device characterized in that it is acted toward the through position (a) by the pressure existing in the. 11. The hydraulic control device according to claim 9, wherein the bypass conduit (22) is the load holding valve (H).
A hydraulic control device characterized in that the hydraulic control device is connected to the one working conduit (4) that includes or directly to the tank (T). 12. The hydraulic control device according to claim 1, wherein the damping throttle (13) is provided in a flow direction toward the load holding valve (H).
A hydraulic control device comprising an open check valve (20) for bypassing the valve. 13. A hydraulic control device according to any one of claims 1 to 5 and claim 12, wherein the open check valve (20) is the valve (15 ′, 15 ″ ″).
A hydraulic control device characterized in that it is structurally integrated in, preferably in its valve element (16 ', 16 "). 14. The hydraulic control device according to claim 1, claim 6 to claim 9, or claim 11 or claim 12, wherein the pressure accumulator (31) is the throttle passage (D ₁ ). And a damping throttle (13) connected to the control pressure conduit (12). 15. The hydraulic control device according to claim 14, wherein the check valve (32) for shutting off in the flow direction opposite to the other working conduit (5) comprises the throttle passage (D ₁ ).
And a hydraulic pressure control device provided in the control pressure conduit (12) between the other working passage (5) and the other working passage (5). 16. Hydraulic control system according to at least one of claims 1 to 15, characterized in that the working conduit (4,5) is a control valve (C), preferably a directional control valve, on the inlet side. A safety shut-off device (A), which is preferably actuable by a working pressure medium via control means (Z) in response to a respective demand, and at least one lift, load moment Or load pressure sensor (43) and control means (Z)
At least one relief valve (36) for said valve element (16, 16 ', 16 ", 1
6 ″ ′) and the permanent force (f) acting on the blocking element (16 ^IV ) is the opening control pressure of the load holding valve (H),
With respect to the setting of the damping throttle (13) and the response characteristic of the safety cutoff device (A), the load holding valve (H) can move into its load holding position when the safety cutoff device (A) responds. The hydraulic control device is characterized in that 17. Hydraulic control system according to claim 16, wherein the sensor (43) is configured as an electrical or electronic sensor and the relief valve (36) is configured as a solenoid valve actuable by the sensor (43). A hydraulic control device characterized in that