DE102022126034A1 - Valve arrangement for work machines with oil-hydraulic tools - Google Patents

Abstract

The invention relates to a valve arrangement for a work machine with an oil-hydraulic tool (47), - with a first directional control valve (30), which is connected to a first pressure line (P1) and a first working line (A1), - with a second directional control valve (31) , which is connected to a second pressure line (P2) and a second working line (A2), - to a 4/2-way valve (32), which is connected to an inlet pressure line (Pa), a discharge line (T), a first control line (C ) and a blocked connection (D), - with a shuttle valve (33) with a first lockable inflow (34) and a second lockable inflow (35) as well as with an outflow (36), whereby - the 4/2-way valve (32) is electrically actuated and in a rest position connects the form pressure line (Pa) to the first control line (C) and in a controlled position connects the first control line (C) to the drain line (T).

Description

The present invention relates to a valve arrangement with the features of the preamble of claim 1 and a work machine with the features of the preamble of claim 7, a method for protecting a work machine and a use of a valve arrangement according to the invention.

Work machines with hydraulic systems, especially mobile hydraulic construction machines, are used in a variety of ways on construction sites for demolition and dismantling work, but also in civil engineering and forestry. So-called long-arm excavators or demolition excavators are used here. The long booms and sticks make mobile hydraulic construction machines a good tool for using hydraulic attachments for the respective purpose, even at heights of over 20 m. When operating mobile hydraulic construction machines, the hydraulic hoses, which represent the hydraulic system of the attachments, are exposed to external influences due to aging processes or weather, which can cause damage to the hydraulic hoses. However, other and much more unpredictable sources of damage include external mechanical influences on the hydraulic hoses caused by work in areas that are not entirely manageable. The excavator's operating personnel do not see every part of the handle of the mobile hydraulic construction machine during operation, so that hydraulic hoses can get caught on, for example, sharp objects on the construction site, be punctured, cut open and crushed and thus be damaged. Due to unavoidable aging processes and unforeseeable external influences, an oil leak in the hydraulic hoses can occur during regular operation of the construction machine. It is, among other things, from the disclosure document EP 25 47 912 It is known to interrupt lines of the hydraulic system on the attachment that are damaged due to broken pipes so that the attachment does not make uncontrolled movements, remains in a rigid position and there are no safety risks on the construction site. However, the hydraulic system is only interrupted on the side of the attachment, which is critical because the long booms and sticks of mobile hydraulic construction machines also require long hydraulic lines that have to be routed to the end of the stick to the attachment, which often results in an oil leak Over 400 liters of oil can escape in less than half a minute and hit the bottom of the construction site. The loss of oil not only means additional costs of replacing the lost oil, but also significant environmental pollution of the construction site.

The same applies to the use of harvesters in forestry, some of which carry tongs on long outriggers for grasping tree trunks, which, in addition to the hydraulic unit for the tongs, are also equipped with a hydraulic motor for rotating the tongs.

The invention is therefore based on the object of specifying a reliable, relatively simple valve arrangement and an environmentally friendly hydraulic work machine as well as a method for controlling such a work machine and a corresponding use of a valve arrangement.

This object is achieved by a valve arrangement with the features of claim 1 and by a work machine with the features of claim 7 as well as by a method for controlling a work machine with the features of claim 16 and a use with the features of claim 18.

• - mit einem ersten Wegeventil, insbesondere einem ersten 2/2-Wegeventil, das mit einer ersten Druckleitung P1 und einer ersten Arbeitsleitung A1 verbunden ist,
• - mit einem zweiten Wegeventil, insbesondere einem zweiten 2/2-Wegeventil, das mit einer zweiten Druckleitung P2 und einer zweiten Arbeitsleitung A2 verbunden ist,
• - mit einem 4/2-Wegeventil, das mit einer Vordruckleitung Pa, einer Abflussleitung T, einer ersten Steuerleitung C und einer zweiten Steuerleitung D verbunden ist,
• - mit einem Wechselventil mit einem ersten sperrbaren Zufluss und einem zweiten sperrbaren Zufluss sowie mit einem Abfluss, wobei
• - das 4/2-Wegeventil elektrisch betätigbar ist und in einer Ruhestellung die Vordruckleitung Pa mit der ersten Steuerleitung C verbindet und in einer angesteuerten Stellung die erste Steuerleitung C mit der Abflussleitung T verbindet,

können in der Ruhestellung des 4/2-Wegeventils sowohl das erste Wegeventil als auch im Wesentlichen gleichzeitig das zweite Wegeventil geschlossen werden. Die Ruhestellung ist bevorzugt stromlos, also mittels eines Notausschalters oder aufgrund einer elektrischen Abschaltung einnehmbar.Because a valve arrangement for a work machine is provided with an oil-hydraulic tool

• - with a first directional valve, in particular a first 2/2-way valve, which is connected to a first pressure line P1 and a first working line A1,
• - with a second directional valve, in particular a second 2/2-way valve, which is connected to a second pressure line P2 and a second working line A2,
• - with a 4/2-way valve which is connected to an inlet pressure line Pa, a discharge line T, a first control line C and a second control line D,
• - with a shuttle valve with a first lockable inflow and a second lockable inflow and with an outflow, whereby
• - the 4/2-way valve is electrically actuated and in a rest position connects the inlet pressure line Pa with the first control line C and in a controlled position connects the first control line C with the drain line T,

In the rest position of the 4/2-way valve, both the first directional valve and the second directional valve can be closed essentially at the same time. The rest position is preferably de-energized, i.e. can be assumed by means of an emergency stop switch or due to an electrical shutdown.

The second control line D is preferably permanently blocked and in the activated position of the 4/2-way valve is connected to the inlet pressure line Pa.

If the first lockable inflow of the shuttle valve is connected to the first pressure line P1, the second lockable inflow of the shuttle valve is connected to the second pressure line P2 and the outflow of the shuttle valve is connected to the inlet pressure line Pa, in the rest position of the 4/2-way valve both are 2/ 2-way valves closed due to the pressure in the higher pressure pressure line. For this purpose, it is advantageously provided that the control line C is connected to the first 2/2-way valve and the second 2/2-way valve in such a way that it pilots them into the closed position when the control line C is pressurized.

An emergency stop function can be achieved particularly easily and reliably if the 4/2-way valve is electrically actuated in a working position and can be de-energized using an emergency stop switch. The emergency stop switch is particularly advantageously arranged in a work cabin of the work machine so that it can be operated manually.

Because in a generic work machine it is provided that at least one directional valve, in particular a 2/2-way valve, is assigned to the at least two hydraulic lines, which is designed to close the hydraulic line in an emergency, the at least one directional valve being assigned to each of the two hydraulic lines in the area of the boom in the hydraulic line or in the area of the frame in the hydraulic line between the valves and the oil-hydraulic tool, if a hydraulic line breaks in the area of the boom, the leakage of hydraulic oil from the upstream hydraulics of the work machine can be largely prevented.

The directional control valves are preferably hydraulically pilot-controlled. In particular, they have an opening pressure between 1 bar and 10 bar, in particular between 1.5 bar and 5 bar and particularly preferably around 2 bar within the usual tolerances. This means that the pressure loss remains relatively low. The directional control valves are further preferably designed for working pressures between 200 bar and 500 bar, preferably between 300 bar and 450 bar and in particular 350 bar to 400 bar. Finally, the valve arrangement is preferably designed for a flow rate (volume flow) of 400 liters per minute (l/min) to 2500 l/min, in particular 600 l/min to 1500 l/min and particularly preferably 700 l/min to 1350 l/min .

The valve arrangement is preferably constructed modularly, so that, for example, one directional valve can be mounted on one side of the boom and the other directional valve on the other side of the boom.

A particularly advantageous embodiment is in which the directional control valves of the valve arrangement can be connected directly to the shut-off valves or quick-change connections of the work machine or can even replace them. Ball valves are often installed in the boom area of an excavator and must be closed to change the attachment. Instead of these ball valves, the valve arrangement according to the invention can be mounted, so that there is an additional benefit through the automatic closing of the valves when the excavator is switched off and a saving in working time, in addition to increased operational safety.

It is conceivable that the directional control valves are closed by pressing an emergency stop switch and, after the leak has been eliminated, are opened again by pressing the emergency switch again. However, it is also possible for the directional control valves to be automatically controlled by a sensor that detects a pressure drop or to close hydraulically fully automatically when the pressure drops.

If the at least two hydraulic lines of the work machine rest in a protected area on an upper side of the boom or are formed by channels and the respective directional control valve is arranged in this protected area, the probability of damage to the hydraulic lines on the pressure side of the valve arrangement and the valve arrangement itself is particularly high Demolition operations reduced. The respective directional valve or 2/2-way valve is preferably integrated in a valve block, which can be flanged to a channel, for example.

Preferably, the at least two hydraulic lines directly supplying the tool are each attached to the tool in a first attachment point and to the boom in a second attachment point and form a flexible hose bend between the two attachment points, the at least one directional control valve or 2/2-way valve is each arranged in the area of the boom outside the flexible hose bend. The two directional control valves are preferably connected to one another hydraulically and/or electrically.

If the second attachment point of each hose bend is on the assigned directional control valve, further fittings or passive leakage protection in this area are unnecessary.

Preferably, the oil-hydraulic tool is an excavator tool, a demolition shear, a forestry tool or a civil engineering tool. With these tools and their usual area of application, there is a particularly high risk of a line breaking as a result of damage during operation. The safety device described so far is particularly advantageous if the frame is self-propelled.

The emergency that leads to the 2/2-way valves being shut off is advantageously a breakage of at least one hose bend, particularly in the immediate vicinity of a tool mounted on the boom.

Such a work machine preferably has a valve arrangement with the features described above.

1. a. Wenn ein Leck in wenigstens einer der Hydraulikleitungen zwischen dem ölhydraulischen Werkzeug und den Ventilen auftritt, Bewegen des wenigstens einen Wegeventils bzw. 2/2-Wegeventils in eine Sperrstellung (Ruhestellung) und dadurch Absperren der wenigstens zwei Hydraulikleitungen,
2. b. Nach Beheben der Leckage, Überführen des wenigstens einen Wegeventils bzw. 2/2 Wegeventils in die Ausgangsstellung.

In addition, a method for protecting a work machine as described above is proposed, which has the following sequential steps:

1. a. If a leak occurs in at least one of the hydraulic lines between the oil-hydraulic tool and the valves, moving the at least one directional valve or 2/2-way valve into a blocking position (rest position) and thereby shutting off the at least two hydraulic lines,
2. b. After eliminating the leak, transfer the at least one directional valve or 2/2 directional valve to the starting position.

This means that if a hydraulic line breaks, the amount of oil escaping can be effectively limited, even if the hydraulic pump of the machine continues to deliver. Damage to the hydraulic pump due to idling can be prevented in this way. The process also serves occupational safety and hydraulic oil can be saved (resource protection).

In particular, the oil-hydraulic tool can comprise a double-acting hydraulic cylinder and the two hydraulic lines connected to the double-acting hydraulic cylinder in step b. be blocked off. This also prevents a further stroke of the hydraulic cylinder, which would otherwise release the unpressurized oil from the unpressurized working space into the environment.

When using a valve arrangement described above in a work machine to prevent oil from escaping uncontrollably from the hose break point in the event of a hose break in the area of a hose bend of the two working lines, a particularly high level of reliability is achieved with simple control in an emergency.

In addition, a mobile hydraulic construction machine having a superstructure, a substructure, a boom assembly, preferably with a boom and an intermediate boom as well as a stick, an attachment connected to the stick and a hydraulic system for moving the boom assembly and the attachment can be provided. The hydraulic system has at least one pump and an additional valve block, the additional valve block being designed to be able to regulate the oil flow of at least two hydraulic lines connecting the attachment to the pump in order to control the attachment. The hydraulic lines are each assigned at least one emergency stop valve, which is designed to close the hydraulic line in an emergency, the at least one emergency stop valve being arranged in the area of the boom assembly in the hydraulic line and/or in the superstructure on the flow side of the additional valve block remote from the pump.

The emergency stop valves allow the hydraulic lines to be closed in the event of a leak, thereby largely preventing hydraulic oil from escaping. It is particularly easy to retrofit the emergency stop valves in the superstructure area. The use of emergency stop valves in the arm area is advantageous as this is of great benefit in the event of a leak in the area between the boom assembly and the attachment.

Preferably, the at least two hydraulic lines lie in a protected area on an upper side of the handle or are formed by channels, with the respective emergency stop valve located in this protected area. A protected area means that the hydraulic lines are rigid pipes, especially made of metal, that are protected from external influences. These protected areas must be distinguished from areas of the hydraulic line with flexible hoses, which can quickly tear or be damaged.

The hydraulic lines are preferably each attached to the attachment in a first attachment point and to the handle in a second attachment point and form a flexible hose bend between the two attachment points, with the at least one emergency stop valve preferably being arranged in the area of the handle outside of the flexible hose bend. During regular work with mobile hydraulic construction machinery, oil leaks often occur on the flexible hose bends, as their nature makes them susceptible to, for example, getting caught on parts of the construction site. However, the hose bends are essential for the ver turning the construction machine, as without the hose bends no large movements of the boom assembly and the attachments would be possible. Closing the emergency stop valves and thus the hydraulic lines and the hydraulic system prevents further oil from escaping in the event of a leak.

The emergency stop valves are preferably electronically controlled solenoid valves, which are particularly cost-effective. The emergency stop valves can be 2-way valves and the hydraulic system then includes at least one return line which connects the emergency stop valves to a hydraulic oil tank from which the hydraulic system is fed by means of the pump. In this case, it is not necessary to communicate with the auxiliary valve block because the hydraulic oil flow through the hydraulic lines in the area of the auxiliary valve block does not have to be interrupted.

In a further preferred embodiment, the mobile hydraulic construction machine comprises an emergency stop actuation device which communicates with the emergency stop valves and/or optionally additionally with the additional valve block and is set up to close the emergency stop valves when actuated.

Preferably, the emergency stop actuation device is arranged in a driver's cab of the mobile hydraulic machine. If the driver of the mobile hydraulic construction machine detects a leak, he can activate the emergency stop device and thus prevent the hydraulic oil from continuing to leak at the breakage point.

Preferably, at least one sensor is assigned to the at least two hydraulic lines, which is designed to detect a leak in the at least two hydraulic lines, the at least one sensor communicating with the emergency stop valves and/or the additional valve block. In this case, the emergency stop valves can be closed automatically in the event of a leak and pressure drop in the hydraulic line.

In a preferred embodiment, the mobile hydraulic construction machine is a long-arm excavator that has a reach height in a range of 15 m to 90 m and in particular a weight class between 25 t and 400 t.

1. a) Detektieren eines Lecks in einer der Hydraulikleitungen zwischen dem Anbaugerät und dem Zusatzventilblock,
2. b) Schalten wenigstens eines Notstoppventils, das jeweils im Bereich der Auslegerbaugruppe und/oder im Oberbau auf der pumpenfernen Strömungsseite des Zusatzventilblocks in einer der wenigstens zwei Hydraulikleitungen angeordnet ist und dadurch Absperren der wenigstens zwei Hydraulikleitungen.

Furthermore, a method for controlling a mobile hydraulic construction machine having a superstructure, a substructure, a boom assembly with a stick, an attachment connected to the stick and a hydraulic system for moving the boom assembly and the attachment is provided, the hydraulic system having at least one pump and one Additional valve block, as well as at least two hydraulic lines connecting the attachment to the pump, the additional valve block being connected to the at least two hydraulic lines. The procedure includes the following sequential steps:

1. a) detecting a leak in one of the hydraulic lines between the attachment and the additional valve block,
2. b) switching at least one emergency stop valve, which is arranged in the area of the boom assembly and/or in the superstructure on the flow side of the additional valve block remote from the pump in one of the at least two hydraulic lines and thereby shutting off the at least two hydraulic lines.

• - Verbindung der Hydraulikleitung mit der Rücklaufleitung mittels des Notstoppventils, wobei die Rücklaufleitung mit einem Hydrauliköltank verbunden ist, aus dem das Hydrauliksystem mittels der Pumpe gespeist ist.

Preferably, the emergency stop valves are 2-way valves and the hydraulic system includes at least one return line and the following is provided in step b) of the method:

• - Connection of the hydraulic line to the return line by means of the emergency stop valve, the return line being connected to a hydraulic oil tank from which the hydraulic system is fed by means of the pump.

• - Ansteuern des Zusatzventilblocks und dadurch Absperren der wenigstens zwei Hydraulikleitungen, wobei Schritt b) darauf mit einer vorgegebenen Zeitverzögerung erfolgt.

The method preferably comprises the following step between steps a) and b):

• - Activating the additional valve block and thereby shutting off the at least two hydraulic lines, with step b) then taking place with a predetermined time delay.

Preferably, the method includes detection by inspection by an operating personnel or by a sensor arranged in the hydraulic line.

• - Manuelles Betätigen der Notausbetätigungsvorrichtung durch das Bedienpersonal.

The mobile hydraulic construction machine preferably comprises an emergency stop actuation device which communicates with the emergency stop valves and/or the additional valve block and the method according to step a) comprises the following step:

• - Manual actuation of the emergency stop device by the operating personnel.

The mobile hydraulic construction machine can be designed as described above.

Two preferred embodiments of the invention are explained in more detail below with reference to the drawings. Identical or functionally identical components are provided with the same reference numerals in the figures.

• 1: eine räumliche Darstellung einer mobilen hydraulischen Baumaschine,
• 2: eine Draufsicht auf die mobile hydraulische Baumaschine aus 1,
• 3: eine schematische Darstellung einer Ausführungsform eines Hydrauliksystems eines Anbaugeräts der mobilen hydraulischen Baumaschine aus 1,
• 4: eine schematische Darstellung einer weiteren Ausführungsform eines Hydrauliksystems eines Anbaugeräts, sowie
• 5: eine Ventilanordnung einer Ausführungsform in Sperrstellung.

The figures show:

• 1 : a spatial representation of a mobile hydraulic construction machine,
• 2 : a top view of the mobile hydraulic construction machine 1 ,
• 3 : a schematic representation of an embodiment of a hydraulic system of an attachment of the mobile hydraulic construction machine 1 ,
• 4 : a schematic representation of a further embodiment of a hydraulic system of an attachment, as well as
• 5 : a valve arrangement of an embodiment in the blocked position.

The 1 shows a mobile hydraulic construction machine 1 in a preferred embodiment as a long-arm boom excavator with a substructure 2, which is connected to a superstructure 4 via a swivel mechanism 3 rotatable about a pivot axis S. With the help of the swivel mechanism 3, a controlled swivel movement between the superstructure 4 and the substructure 2 about the swivel axis S is possible. In general, a distinction can be made between mobile excavators and crawler excavators. The substructure 2 can, on the one hand, have tires in a chassis and is referred to as a mobile excavator, with mobile excavators only being used in the weight class up to 25 t, and, on the other hand, have chains, so that we are talking about crawler excavators, which are used in all weight classes come. As self-propelled land vehicles, mobile and crawler excavators are to be distinguished from other types of excavators such as floating excavators. In the preferred embodiment, the long-arm boom excavator 1 is implemented as a crawler excavator, which is in a weight class between 25 t and 400 t, which is typical for demolition work. The superstructure 4 has a driver's cab 5 at its end in the direction of travel F (straight alignment) and a counterweight 6 opposite the driver's cab 5 1 and 2 A three-part boom assembly 7 can be seen, which is attached to the superstructure 4 next to or behind the driver's cab 5. The boom assembly 7 has three links 8,9,10 lying one behind the other. A first link 8, called a boom, a second link 9, called an intermediate boom, and a third link furthest from the superstructure, which is called a stick 10, with two successive links being pivotally mounted on one another by means of bolts. The boom assembly 7 further includes a boom cylinder 11, which can move the first link 8, and an intermediate boom cylinder 12, which can move the second link 9 of the boom assembly 7. Furthermore, a handle cylinder 22 is provided, which can be driven to move the handle 10. An attachment 14 is attached to the free end of the handle 10, which is penetrated by a handle head bolt 13. This connection can preferably be made using a quick coupler. The attachment 14 and the quick coupler can also be pivoted about the pivot axis defined by the handle head bolt 13. The attachment 14 is a gripping tool in this embodiment, but all hydraulic attachments such as scissors can be used.

The mobile hydraulic construction machine 1 includes a hydraulic system which, among other things, drives the boom cylinder 11 and the intermediate boom cylinder 12 as well as the arm cylinder 22 using hydraulic oil. The hydraulic oil flow and the associated movements are controlled and controlled by a main valve block (not shown) of the hydraulic system located in the superstructure 4. The main valve block includes valves that regulate a supply amount of the hydraulic oil to one of the hydraulic cylinders. Furthermore, the main valve block is responsible for controlling a hydraulic swivel drive of the swivel mechanism 3 and a hydraulic travel drive for the chains of the substructure 2. Associated with the hydraulic system and located in the superstructure 4 are also an additional valve block 15, a hydraulic oil tank 16, and a hydraulic pump 17 The hydraulic pump 17 delivers the hydraulic oil of the hydraulic system and is connected to the main valve block and the auxiliary valve block 15 via a hydraulic connection. Several pumps can be used in the hydraulic system if the performance of one pump is not sufficient for the required use or if the system is to be designed redundantly. The additional valve block 15 controls and regulates a hydraulic oil flow to the attachment 14. Starting from the additional valve block 15, hydraulic lines 18 lead to the attachment 14. In the 1 Only one hydraulic line 18 is shown, but depending on the attachment used and the type of construction machine, there may be several, but at least two, hydraulic lines 18. The type of attachment 14 and the movement it can perform define the number of (used and connected) hydraulic lines 18. The hydraulic line 18 is in the area of bolts 19 of the boom assembly 7, between the superstructure 4 and the first link 8, and between the first link 8 and the second link 9 and between the second link 9 and the handle 10, formed by flexible hose lines that are arranged in an arc, also called boom hose bends 20. A flexible hose bend 21 is also formed between a first attachment point on the attachment 14 and a second attachment point on the handle 10. The flexible boom hose bends 20 and the flexible hose bend 21 make it possible for the individual Links of the boom assembly 7 can pivot about the longitudinal axis of the bolts 19 without the hydraulic line 18 being interrupted or tearing. The hose bend 21 and the boom hose bends 20 are formed for each additional hydraulic line 18, not shown here. The parts of the hydraulic line 18, which run centrally along the links of the boom assembly 7 away from the pivot axes or the bolts 19, are realized by rigid metal tubes. The ends of the metal pipes are each connected to a flexible hose line to form the hydraulic line 18. The metal pipes represent a protected area in which the hydraulic line 18 is protected from external damage. In the hydraulic line 18 shown there are two emergency stop valves 23, 24 between the additional valve block 15 and the attachment 14. The emergency stop valves 23, 24 of the at least two hydraulic lines 18 are divided into first emergency stop valves 23 and second emergency stop valves 24 and are in the 1 shown schematically as a rectangle. The first emergency stop valve 23 and the second emergency stop valve 24 can close the corresponding hydraulic line 18 at the respective position. This can ensure that the emergency stop valve 23, 24 located on the side close to the additional valve block in the event of an oil leakage prevents the hydraulic oil located between this emergency stop valve 23, 24 and the hydraulic pump 17 or the hydraulic oil tank 16 in the hydraulic lines 18 from escaping. The first emergency stop valve 23 is located in the superstructure 4 on the flow side of the additional valve block 15 remote from the pump. The second emergency stop valve 24 is located in the hydraulic line 18 in the area of the stem 10 outside the hose bend 21. Particularly preferred is a position that is immediately in front of or in the direction of flow. behind the flexible hose line in the area of the handle head bolt 13, as shown in 1 is shown. Experience has shown that leaks in the hose lines often occur in the area of the handle head bolt 13. The previously described position of the second emergency stop valve 24 makes it possible to maintain the maximum possible amount of hydraulic oil in the hydraulic lines 18 in such a leakage event. If there is an oil leak in the hose bend 21, the oil can remain in the hydraulic line 18 between the second emergency stop valve 24 and additional valve block 15 in the hydraulic lines 18 by closing the second emergency stop valve 24 and leakage is prevented. It is conceivable to use additional emergency stop valves, which, for example, protect against leakage of the boom hose bends 20 of the second link 9. At least one emergency stop valve 23.24 is required per hydraulic line 18. Even the first emergency stop valve 23 prevents the majority of the hydraulic oil from escaping if the flexible hose line leaks in the area of the handle head bolt 13. The emergency stop valves 23,24 clearly differ from conventional pipe rupture protection devices, which are now installed as standard in mobile hydraulic construction machines. The pipe burst protection devices, not shown, are installed on the attachment 14 and prevent uncontrolled movements of the attachment 14 in the event of pipe bursts in order to protect operating personnel and construction site personnel. They maintain the pressure of the hydraulic oil in the attachment 14 or the working spaces of the hydraulic cylinders installed therein and allow the attachment 14 to remain in a rigid position. The emergency stop valves 23, 24 interrupt the hydraulic system at at least one point towards the additional valve block 15. The hydraulic oil in the hydraulic line between the break point and the emergency stop valve 23,24 escapes. However, the emergency stop valve 23,24 prevents large amounts of hydraulic oil from escaping and thus contributes to environmental protection during demolition work.

The 3 shows a part of a hydraulic system, shown only schematically, which is used to control movement of the attachment 14. The hydraulic valves of the additional valve block 15 are electrically pilot-controlled to move the attachment 14, which is not shown in the figure. The hydraulic pump 17 supplies the additional valve block 15 with the required oil pressure to control the attachment 14 or its hydraulic cylinder. The additional valve block 15 regulates the volume flow of the hydraulic oil through the four hydraulic lines 18 shown as examples and can thus control a movement of the attachment 14. There are a first emergency stop valve 23 and a second emergency stop valve 24 per hydraulic line 18. The first emergency stop valves 23 and the second emergency stop valves 24 are each located in two different sections of the hydraulic line 18. The boom hose bends 20 closest to the additional valve block and the flexible hose bends 21 in the area of the stick head bolt 13 are shown.

On the one hand, the first emergency stop valves 23 are arranged in the superstructure 4, in a superstructure section of the respective hydraulic line 18, which is located on the flow side of the additional valve block 15 remote from the pump, and on the other hand, the second emergency stop valves 24 are in a boom assembly section of the respective hydraulic line 18, which is located outside of the superstructure 4 and is located in the area of the handle 10 outside the flexible hose bends 21, as already described above. The emergency stop valves 23,24 are open during regular operation of the mobile hydraulic construction machine 1, so that the hydraulic oil can flow unhindered through the emergency stop valves 23,24. The emergency stop valves 23, 24 are controlled by an emergency stop actuation device 25. If the emergency stop actuation device 25 is actuated, the hydraulic lines 18 are closed by means of the emergency stop valves 23, 24 and the hydraulic oil flow is stopped. The emergency stop actuation device 25 communicates electronically with the additional valve block 15 and switches the emergency stop valves 23, 24.

After a leak has been detected in one of the hydraulic lines 18 between the attachment 14 and the additional valve block 15, the emergency stop valves 23, 24 are switched and the hydraulic lines 18 are shut off. In the 3 The closed state of the emergency stop valves 23, 24 is shown, which is achieved by actuating the emergency stop actuation device 25.

In a preferred embodiment, the emergency stop valves 23, 24 are electronically controlled solenoid valves.

In a preferred embodiment, the leak is discovered by the operating personnel and the operating personnel then actuates the emergency stop actuation device 25 and the emergency stop valves 23, 24 are switched and shut off the hydraulic lines 18. The detection can also be carried out by a sensor which is assigned to the hydraulic lines 18 and the emergency stop actuation device 25 can then be actuated automatically.

In a preferred embodiment, the additional valve block 15 is first activated by actuating the emergency stop actuation device 25 and the additional valve block 15 blocks the at least two hydraulic lines 18. The emergency stop valves 23, 24 are then switched and the hydraulic lines 18 are closed with a predeterminable time delay.

The 4 shows a further embodiment of a part of the hydraulic system, predominantly analogous to 3 . In this case, the attachment 14 is hydraulically pilot-controlled by a low-pressure line. The boom hose bends 20 and the hose bends 21 were not drawn. The differences are discussed below. In the in 4 In the embodiment shown, the first emergency stop valves 23 in the superstructure section of the hydraulic lines 18 are implemented by 2-way valves 26, which can be connected to the hydraulic oil tank 16 of the hydraulic system via a return line 27. During regular operation, the second emergency stop valves 24, which in one embodiment are electronically controlled solenoid valves, are open in the boom assembly section and the 2-way valves 26 in the superstructure section are in a first switching position, which flows hydraulic oil from the additional valve block 15 via the hydraulic line 18 to the attachment 14 leaves.

After an oil leak has been detected by operating personnel or a sensor, the second emergency stop valves 24 in the boom assembly section of the hydraulic lines 18 are switched and closed by actuating the emergency stop actuation device 25 and the 2-way valves 26 switch to a second switching position shown, in which hydraulic oil flows from Additional valve block 15 flows into the hydraulic oil tank 16 via the return line 27.

It is conceivable to use more than two emergency stop valves 23.24 per hydraulic line 18.

In both versions of the hydraulic systems, one electrical and one hydraulically pilot-controlled, an oil leak can be detected by operating personnel or a sensor. The emergency stop actuation device 25 can, for example, be designed as an actuation button in the driver's cab 5 or on the boom assembly 7 or be accessible via a control of the mobile hydraulic construction machine 1, which has the necessary controls for controlling the mobile hydraulic construction machine 1. By actuating the emergency stop actuation device 25, the emergency stop valves 23, 24 are switched and the hydraulic oil flow is stopped. By activating the emergency stop actuation device 25 again, the emergency stop valves 23, 24 can be switched back and the hydraulic lines 18 to the attachment 14 can be opened again. The emergency stop valves 23, 24 are switched back when the oil leak in the hydraulic lines 18 has been eliminated. If the leak is detected using a sensor, it is conceivable that an alarm is issued, whereupon the operating personnel can actuate the emergency stop actuation device 25. However, it is also possible for the emergency stop valves 23, 24 and/or the additional valve block 15 to be automatically controlled by the sensor that detects a drop in pressure. In a further embodiment, it is provided to use emergency stop valves which close automatically when there is a pressure drop in the hydraulic line 18.

In the 5 Finally, a valve arrangement of an embodiment of an emergency stop actuation device is shown. The valve arrangement includes a first 2/2-way valve 30, which is connected to a first pressure line P1 and a first working line A1, a second 2/2-way valve 31, which is connected to a second pressure line P2 and a second working line A2 4/2-way valve 32, which is shown here in an assembly with the second 2/2-way valve 31 and which is connected to an inlet pressure line Pa, a discharge line T, a first control line C and a blocked connection D, as well as a shuttle valve 33 with a first blockable inflow 34 and a second blockable inflow 35 and with an outflow 36.

The 4/2-way valve 32 can be electrically actuated via an electrical line 37 and connects in the in 5 In the rest position shown, the inlet pressure line Pa is connected to the first control line C and the drain line T is connected to the permanently blocked port D of the 4/2-way valve 32. In an electrically controlled position, the inlet pressure line Pa is connected to the permanently blocked port D and is therefore shut off. The control line C is connected to the drain line T and is therefore essentially depressurized.

The control line C is connected to the first 2/2-way valve 30 and the second 2/2-way valve 31 so that it pilots them into the closed position when the control line C is pressurized.

The 2/2-way valve 30 and the 2/2-way valve 31 are in the rest position shown biased into the closed position by means of a spring 39 (N C). Both valves are controlled via the inlet pressure in the connecting lines P1 or P2 and the working lines A1 or A2. For this purpose, a pilot control line 40 is provided in the 2/2-way valve 30, which runs from the pressure line P1 to a working space (not shown) opposite the spring 39. Another pilot line 41 runs from the working line A1 to the same work area. The spring 39 and the geometric design of the movable valve member and the working space, not shown, are selected so that the 2/2-way valve 30 switches into the open position against the force of the spring 39 at approximately an inlet pressure of 2 bar. Electrical actuation of the directional control valve 30 is not required and is not intended. It is purely pressure controlled. The same applies to the 2/2-way valve 31, in which a pilot control line 43 runs from the pressure line P2 and a pilot control line 44 runs from the working line A2 to a corresponding working space. This valve is also pressure-controlled and opens, for example, when the pressure is 2 bar.

In the in 5 In the rest position shown, the two 2/2-way valves 30 and 31 are closed. If pressure builds up in the pressure lines P1 or P2, the respective 2/2-way valve is piloted into the open position via the pilot lines 40 and 43, respectively. At the same time, however, the higher pressure is applied to the drain 36 of the shuttle valve 33 via the connections 34 and 35 of the shuttle valve 33. This higher pressure is then present on the inlet pressure line Pa and is fed via the 4/2-way valve 32, which is in the rest position, to the control line C, which in turn directs this higher pressure to the spring side of the 2/2-way valves 30 and 31 and thus the movable valve members of the 2/2-way valves 30 and 31 are piloted into the closed position. The respective control surfaces of the 2/2-way valves 30 and 31 are dimensioned such that the 2/2-way valves 30 and 31 remain closed at the same pressure in the control line C and in the pilot control lines 40 and 43.

In order to be able to put the working machine into operation from this position of the valve arrangement with a hydraulic tool 47 connected to the working lines A1 and A2, the electrical line 37, in which a normally closed emergency stop switch 45 is also connected in series, is supplied with an operating voltage of For example, 24 V is applied. This switches the 4/2-way valve 32 into the working position in which the control line C is connected to the outlet T and the inlet pressure line Pa is connected to the blocked port D. If pressure is now applied from the hydraulic system of the work machine, for example to the pressure line P1, the 2/2-way valve is subjected to the corresponding pressure via the pilot control line 40. The shuttle valve 33 then directs this pressure, as described above, to the drain 36 and the inlet pressure line Pa, which, however, is connected to port D in the 4/2-way valve 32 and is therefore blocked. The control line C is connected to the drain T and is therefore unpressurized. This means that there is no pressure in the control line C that would counteract the opening of the 2/2-way valve 30. The 2/2-way valve 30 switches to the open position. A backflow arises from the hydraulic unit 47, which leads to an increase in pressure in the working line A2. This increase in pressure causes the 2/2-way valve 31 to open via the pilot control line 44, so that the valve arrangement described so far is hydraulically permeable and the hydraulic unit 47 can be operated in the usual manner.

The same applies in the opposite case. If the pressure line P2 is first pressurized with hydraulic pressure, the 2/2-way valve 31 opens first and then the 2/2-way valve 30 opens due to the pressure increase in the working line A1.

The valve arrangement can, for example, be attached to a boom or arm of an excavator. The pressure lines P1 and P2 can then be firmly mounted as pipelines on the boom or arm and connected to the valve arrangement. The valve arrangements can each be designed as a valve block. The valve blocks are preferably each attached to one side of the boom or stick. For example, where ball valves are traditionally installed. From the valve Arrangement to the hydraulic unit 47 run flexible hose bends 48 and 49, which are indispensable for movable hydraulic units 47. If, during operation, as described in more detail above, a hose bend 48, 49 gets stuck on a protruding metal iron, for example when a building is being demolished, and thereby tears off, in conventional hydraulic systems a large amount of hydraulic oil would escape from the break point. In such a case, the operator of the work machine can actuate the emergency stop switch 45 and thus de-energize the 4/2-way valve 32. It then falls into the in 5 rest position shown. If the pressure in the hydraulic line falls below the opening pressure of the 2/2-way valve due to the leak, the valve closes automatically. Any hydraulic pressure generated by the hydraulic system in the pressure lines P1 and P2 is then applied to the shuttle valve 33. The higher of the two pressures is applied to the terminal 36 and passed on to the control line C. The control line C then brings both 2/2-way valves 30 and 31 into the closed position together with the spring force of the springs 39. As a result, if a hose bend 48, 49 breaks and the emergency switch 45 is actuated, the hydraulic system in the valve arrangement is completely closed, so that no further hydraulic fluid can escape from the hydraulic system.

It should be emphasized here that the valve arrangement does not replace the function of a conventional hose rupture protection device, which can additionally be provided directly on the two connections of the hydraulic unit 47 in order, for example, to prevent a boom or a suspended load from suddenly breaking when a hose bend 48, 49 breaks falls down. Such hose rupture devices respond automatically to a high volume flow that exceeds specified limit values. They are basically self-acting, volume flow controlled check valves. However, in the event of a hose break, these cannot prevent large amounts of hydraulic fluid from escaping from the hydraulic system itself if a hose bend 48, 49 breaks.

The 2/2-way valves 30 and 31 can be identical in construction, but they are preferably chosen so that one of the 2/2-way valves has a larger opening cross section than the other in order to be adapted to the different volume flows, for example in double-acting hydraulic units.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2547912 [0002]

Claims (18)

Valve arrangement for a work machine with an oil-hydraulic tool (47), - with a first directional control valve (30) which is connected to a first pressure line (P1) and a first working line (A1), - with a second directional control valve (31), which is connected to a second pressure line (P2) and a second working line (A2), - with a 4/2-way valve (32) which is connected to an inlet pressure line (Pa), a discharge line (T), a first control line (C) and a blocked connection (D), - with a shuttle valve (33) with a first lockable inflow (34) and a second lockable inflow (35) and with an outflow (36), whereby - The 4/2-way valve (32) is electrically actuated and in a rest position connects the inlet pressure line (Pa) to the first control line (C) and in a controlled position connects the first control line (C) to the drain line (T). Valve arrangement according to Claim 1 , characterized in that the first lockable inflow (34) of the shuttle valve (33) with the first pressure line (P1), the second lockable inflow (35) of the shuttle valve (33) with the second pressure line (P2) and the outflow (36) of the shuttle valve (33) is connected to the inlet pressure line (Pa). Valve arrangement according to Claim 1 or 2 , characterized in that the control line (C) is connected to the first 2/2-way valve and the second 2/2-way valve so that it pilots them into the closed position when the control line (C) is pressurized. Valve arrangement according to one of the preceding claims, characterized in that the 4/2-way valve (32) is electrically actuated in a working position and can be de-energized by means of an emergency stop switch (45). Valve arrangement according to Claim 4 , characterized in that the emergency stop switch (45) is arranged to be operated manually in a work cabin of the work machine. Valve arrangement according to one of the preceding claims, characterized in that the first directional valve (30) is a 2/2-way valve and/or the second directional valve (31) is a 2/2-way valve. Work machine comprising a frame and a boom, and an oil-hydraulic tool carried by the boom, and a hydraulic system comprising a hydraulic pump, valves, at least two hydraulic lines (P1, P2; A1, A2) and at least one hydraulic actuator (47), the valves are designed to be able to regulate an oil flow of the at least two hydraulic lines (P1, P2; A1, A2) connecting the actuator to the hydraulic pump to control the actuator (47), characterized in that the at least two hydraulic lines (P1, P2; A1, A2) are each assigned at least one directional valve (30, 31), which is designed to close the hydraulic line (P1, P2; A1, A2) in an emergency, the at least one directional valve (30, 31) being each of the both hydraulic lines (P1, P2; A1, A2) in the area of the boom in the hydraulic line (P1, P2; A1, A2) or in the area of the frame in the hydraulic line (P1, P2; A1, A2) between the valves and the oil-hydraulic Tool is arranged. working machine Claim 7 , characterized in that the at least two hydraulic lines (P1, P2; A1, A2) rest in a protected area on an upper side of the boom or are formed by channels and that the respective directional control valve (30, 31) is arranged in this protected area. working machine Claim 7 or 8th , characterized in that the at least two hydraulic lines (P1, P2; A1, A2) are each attached to the tool in a first attachment point and to the boom in a second attachment point and form a flexible hose bend (48, 49) between the two attachment points , wherein the at least one directional control valve is arranged in the area of the boom outside the flexible hose bend (48, 49). working machine Claim 9 , characterized in that the second attachment point of each hose bend (48, 49) is located on the respectively assigned directional control valve (30,31). Working machine according to one of the preceding Claims 7 until 10 , characterized in that the oil-hydraulic tool is an excavator tool, a demolition shear, a forestry tool or a civil engineering tool. Working machine according to one of the preceding Claims 7 until 11 , characterized in that the frame is self-propelled. Working machine according to one of the preceding Claims 7 until 12 , characterized in that the emergency is a break of at least one hose bend (48, 49). Working machine according to one of the preceding Claims 7 until 13 , characterized in that the first directional valve (30) is a 2/2-way valve and / or the second directional valve (31) is a 2/2-way valve. Working machine according to one of the preceding Claims 7 until 14 , having a valve arrangement according to one of Claims 1 until 6 . Method for protecting a working machine according to one of the preceding Claims 7 until 15 which comprises the following sequential steps: a. If a leak occurs in at least one of the hydraulic lines (A1, 48; A2, 49) between the oil-hydraulic tool and the directional control valves (30, 31), moving the at least one directional control valve into a blocking position and thereby shutting off the at least two hydraulic lines, b. After eliminating the leak, transfer the at least one directional control valve to the starting position. Procedure according to Claim 16 , characterized in that the oil-hydraulic tool comprises a double-acting hydraulic cylinder (47) and the two hydraulic lines (A1, 48; A2, 49) connected to the double-acting hydraulic cylinder (47) in step b. be blocked off. Use of a valve arrangement according to one of the preceding Claims 1 until 6 in a work machine to prevent oil from escaping uncontrollably from the hose break point in the event of a hose break in the area of a hose bend (48, 49) of the two working lines (A1, A2).

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