Valve device for mobile work machine having hydraulic load

Abstract

The invention relates to a valve arrangement for a mobile working machine (1) having a hydraulic load (47, 50), comprising at least one reversing valve (30, 31, 55, 64), which is connected to a pressure line (P1, P2, 56, 65) and a working line (A1, A2, 52, 54) of the hydraulic load (47, 50) and which comprises a hydraulic control line (C, 58, 63), which is designed to control the pressure line (P1, P2, 56, 65) and the working line (A1, A2, 52, 54) of the hydraulic load (47, 50). Transferring the at least one reversing valve (30, 31, 55, 64) into a first position; a pilot valve (32, 59), which is connected to the hydraulic control line (C, 58, 63); a pressure supply line (Pa, 66); and a pressure relief line (T, 62), the pilot valve (32, 59) being designed to alternately connect the hydraulic control line (C, 58, 63) to the pressure supply line (Pa, 66) and the pressure relief line (T, 62).

Description

[0001] The invention relates to a valve device, the use of such a valve device, a mobile working machine having the features of the preamble of claim 15 and a method for minimizing hydraulic losses in a mobile working machine.

[0002] Mobile hydraulic working machines, in particular construction machines, are used in various forms for demolition and dismantling work on construction sites. However, such mobile working machines are also used in underground engineering and in forestry. Examples of mobile working machines include cranes, excavators, such as also loading and unloading excavators (Umschlagbagger), as well as forestry machines and similar equipment. In the field of demolition, so-called long-boom excavators (English "longfront") or demolition excavators are mainly used. The long boom and the stick (Stiel) make the mobile hydraulic construction machine a good machine tool so that hydraulic attachments can be used for the corresponding objects at heights of more than 20 m. During the operation of the mobile hydraulic construction machine, the hydraulic hoses that form the hydraulic system of the attachment are subject to external influences due to aging processes or weather conditions, which external influences can cause damage to the hydraulic hoses. However, working in areas that are not fully known can also lead to other and many unforeseeable sources of damage due to mechanical effects on the hydraulic hoses from the outside. The operator of the excavator cannot see every part of the boom of the mobile hydraulic construction machine during operation, so that the hydraulic hose may be hooked, pierced, cut and crushed by, for example, sharp objects on the construction site, and thus may be damaged. Due to the inevitable aging process on the one hand and unforeseen external effects on the other hand, oil leakage from the hydraulic hose may occur during the normal operation of the construction machine. In particular, it is known from the publication EP 25 47 912 that the pipeline of the hydraulic system on the attachment is interrupted due to pipe rupture damage, and the attachment does not move uncontrollably, but stays in a fixed position and does not pose a safety risk on the construction site. However, it is dangerous to interrupt the hydraulic system only on the attachment side, because the long boom and boom of the mobile hydraulic construction machine also result in long hydraulic lines, which must be led to the end of the boom for the attachment, so that in the event of oil leakage, more than 400 liters of oil may flow out in less than half a minute, and this oil will fall on the ground at the construction site. This oil loss not only means additional costs due to the need to replace the lost oil, but also causes serious environmental pollution to the construction site.

[0003] A similar situation applies to harvesters used in forestry, which sometimes carry on long booms jaws for gripping tree trunks and which are equipped with hydraulic motors for rotating the jaws in addition to the hydraulic system for the jaws.

[0004] The object of the present invention is therefore to provide a reliable, relatively simple valve device and an environmentally friendly mobile working machine, as well as a method for minimizing hydraulic oil losses in the mobile working machine when a leak occurs in the working line, and a corresponding use of the valve device.

[0005] This object is achieved by a valve device having the features of claim 1 and a use having the features of claim 14 , by a working machine having the features of claim 15 and by a method for minimizing hydraulic oil losses in a mobile working machine having the features of claim 18 .

[0006] Therefore, a valve device for a mobile working machine with a hydraulic load is proposed, which valve device has:

[0007] at least one directional valve, which is connected to the pressure line and the working line of the hydraulic consumer and comprises a hydraulic control line which is designed to switch the at least one directional valve into a first position,

[0008] - a pilot valve, the pilot valve being connected to the hydraulic control pipeline,

[0009] - supply pressure lines, and

[0010] a pressure relief line, wherein the pilot valve is designed to connect the hydraulic control line alternately to a supply pressure line and a pressure relief line.

[0011] The valve device ensures that, when a leak occurs in the working line, the directional valve can be reliably switched to the blocking position and that oil is prevented from flowing out of the leak point to the greatest extent possible.

[0012] Preferably, the first position of the at least one directional control valve is a closed position, in which the oil flow is blocked in both directions. The pilot valve can then ensure that the directional control valve remains in the blocked position.

[0013] The at least one reversing valve is preloaded into a first position by a spring and has two pilot control lines, which are connected to a working chamber opposite the spring, a first pilot control line being connected to the pressure line and a second pilot control line being connected to the working line. The pilot control line enables the reversing valve to be switched to an open position when the hydraulic load is actuated. It is clear to a person skilled in the art that the pilot control line or the working chamber can also be an active surface that causes the reversing valve to move when pressure is applied.

[0014] The pilot valve may be a two-position three-way valve or a two-position four-way valve.

[0015] The pilot valve is electrically operable and connects the supply pressure line to the hydraulic control line in the rest position and connects the hydraulic control line to the pressure relief line in the control position. However, it is also conceivable to control the pilot valve in another way, in particular wirelessly.

[0016] Preferably, the pilot valve is electrically operated in the working position and can be switched electrically without electricity by an emergency shut-off switch. The emergency shut-off switch can be arranged in a manually operable manner in a working compartment of the work machine.

[0017] If the hydraulic load has two working lines, such as in a double-acting hydraulic cylinder, the valve device preferably comprises a first reversing valve and a second reversing valve, the first and second reversing valves being respectively connected to the pressure line and the working line of the common hydraulic load, and the hydraulic control lines being connected to one another, so that when the hydraulic control line is loaded with pressure by the pilot valve, the hydraulic control line pilot controls the two reversing valves to a closed position. Preferably, both reversing valves have the features described above. By connecting the control lines, the two reversing valves are controlled by a single pilot valve. It is also conceivable that two pilot valves can also be used. The pilot valves can then be electrically connected or wirelessly communicate with one another by radio or other means.

[0018] In one embodiment, it can be provided that the valve device includes a shuttle valve, which has a first and second flow inlet that can be blocked, and an outflow outlet that can be blocked. The first and second flow inlets of the shuttle valve that can be blocked are connected to the first pressure line of the first reversing valve, the second and second flow inlets of the shuttle valve that can be blocked are connected to the second pressure line of the second reversing valve, and the outflow outlet of the shuttle valve is connected to the supply pressure line, and the shuttle valve is configured so that the pressure line can be connected to the supply pressure line at a maximum pressure.

[0019] However, the supply pressure line can also be connected to the pressure line and the working line via branchings which are connected in parallel and each have a nonreturn valve which is arranged or designed such that the highest pressure prevailing in the lines is directed toward the supply pressure line.

[0020] The pressure relief pipeline may be a fuel tank pipeline (oil return pipeline) that can be connected to a fuel tank.

[0021] However, it is also conceivable that the pressure relief line is connected to the pressure line and the working line via branches, which are connected in parallel and each have a nonreturn valve, which opens towards the one of the lines with the lower pressure and thereby relieves the pressure when the pressure prevailing in the pressure relief line is loaded. In this embodiment, a return line is not required, which can be advantageous when the valve device is installed at a greater distance from the superstructure.

[0022] The first switching valve and / or the second switching valve may be a 2 / 2-way valve, which blocks the flow of hydraulic oil in two directions in a blocking position and allows the flow of hydraulic oil in two directions in a conducting position.

[0023] Furthermore, it is proposed to use the aforementioned valve device in a working line of a hydraulic consumer in a mobile working machine in order to block the working line if a leak occurs in the working line and to prevent hydraulic oil from escaping from the leak site to the greatest extent possible.

[0024] In addition, a mobile working machine is proposed, which has a substructure, an upper structure and a boom assembly, and a hydraulic system, which includes a hydraulic pump, a volume control valve, a hydraulic load and at least two hydraulic lines, wherein the volume control valve is designed to be able to adjust the oil flow through at least one of the hydraulic lines in order to control the hydraulic load. At least one of the hydraulic lines has a reversing valve, which is designed to close the hydraulic line when a leak occurs in the hydraulic line. The boom assembly can have two or more sections, in particular a boom and a stick. The reversing valve can be, for example, a slide valve, a seat valve, a plate valve or a similar valve.

[0025] Preferably, the reversing valve is arranged between the volume control valve and the hydraulic load, because, when a re-intake valve is installed in a bypass across the volume control valve, for example to prevent cavitation, hydraulic oil may also flow out from the leakage point when the volume control valve is closed.

[0026] Preferably, the mobile working machine comprises a valve device according to the above, and the reversing valve is a part of the valve device.

[0027] In one embodiment, the hydraulic load is a hydraulic cylinder, which is in particular double-acting. As explained above, a reversing valve is present in each hydraulic line. It is also conceivable that more than one reversing valve or more than one valve device is provided in order to provide protection for the hydraulic line at different positions. In addition, multiple control parts of the mobile working machine can each have such a valve device, that is, according to specific needs, multiple hydraulic lines leading to different hydraulic loads can be protected.

[0028] Furthermore, a method is proposed for minimizing hydraulic oil losses in the event of a leak in a working line in a mobile working machine as described above, the method comprising the following steps which are carried out in sequence:

[0029] a. When a leak occurs in the hydraulic line between the hydraulic load and the reversing valve, the reversing valve is moved to the shut-off position, thereby shutting off the hydraulic line,

[0030] b. Ensure that the cut-off position is maintained until the leak is eliminated,

[0031] c. After the leakage has been eliminated, the switchover valve and / or the valve arrangement is switched to an initial state before the leakage or to an initial position.

[0032] Unlike other valves or valve devices that close hydraulic lines, with this method, the mobile working machine can continue to operate and move except for the control part corresponding to the leaking line. With this method, it is possible to prevent a large amount of hydraulic oil from flowing out of the leakage position. Since it is ensured or can be ensured that the shut-off position is maintained until the leakage is eliminated and the hydraulic line is repaired, it is possible to reliably prevent the hydraulic oil from flowing out of the hydraulic line. Valves that do not have this ability are not suitable for use as emergency stop devices to prevent a large amount of hydraulic oil from flowing out of the leaking part. Preferably, the conversion of the reversing valve or valve device to a state such as before the leakage and shut-off of the pipeline is carried out without tools and without replacing or updating components / parts. Particularly preferably, the initial state is automatically achieved after being released, for example, by an operator. This release can include an input in the operating unit, an operation of a switch or the like.

[0033] Other possible embodiments of the valve device, the working machine, and the method are described below.

[0034] Because the valve device for working machines, in particular construction machines with hydraulic devices, is provided with:

[0035] a first directional valve, in particular a first 2 / 2-way valve, which is connected to the first pressure line and the first working line,

[0036] a second directional control valve, in particular a second 2 / 2-way valve, which is connected to the second pressure line and the second working line,

[0037] - a two-position four-way valve, the two-position four-way valve being connected to the pressure supply pipeline, the pressure relief pipeline, the first control pipeline and the second control pipeline,

[0038] a shuttle valve having a first flow inlet which can be blocked and a second flow inlet which can be blocked and an outflow, wherein

[0039] the 4 / 2-way valve is electrically actuatable and, in the rest position, connects the supply pressure line to the first control line and in the actuated position, connects the first control line to the pressure relief line,

[0040] In the rest position of the 2 / 4-way valve, both the first reversing valve and the second reversing valve can be closed substantially simultaneously. Preferably, the rest position can be placed without electricity, that is, can be placed in the rest position by an emergency shut-off switch or due to power failure.

[0041] Preferably, the second control line is permanently blocked and is connected to the supply pressure line in the actuation position of the 4 / 2-way valve.

[0042] If the first shutoff inlet of the shuttle valve is still connected to the first pressure line, the second shutoff inlet of the shuttle valve is still connected to the second pressure line, and the outlet of the shuttle valve is still connected to the supply pressure line, then in the idle position of the 4 / 2-way valve, the two 2 / 2-way valves are closed due to the pressure in the pressure line charged with the higher pressure. For this purpose, it is advantageously provided that the control line is connected to the first 2 / 2-way valve and the second 2 / 2-way valve so that the 2 / 2-way valves are pilot-controlled into the closed position when the control line is charged with pressure.

[0043] The emergency shut-off function is particularly simple and reliable when the 4 / 2-way valve is electrically actuated in the working position and can be switched electrically without power by means of an emergency shut-off switch. For this purpose, the emergency shut-off switch is particularly advantageously arranged in a manually actuable manner in the working compartment of the work machine. The emergency shut-off function can be provided in the event of a leak in the working line.

[0044] Because in the described type of working machine, it can be provided that the at least two hydraulic pipelines are respectively equipped with at least one reversing valve, in particular a 2 / 2-way valve, and the reversing valve is designed to close the hydraulic pipeline in an emergency. The at least one reversing valve of each hydraulic pipeline of the two hydraulic pipelines is arranged in the hydraulic pipeline in the area of ​​the cantilever, or in the area of ​​the lower structure, it is arranged in the hydraulic pipeline between the valve and the oil hydraulic device. As a result, when the hydraulic pipeline in the area of ​​the cantilever is ruptured, the hydraulic oil from the upstream hydraulic device of the working machine can be basically prevented from flowing out.

[0045] The reversing valve is preferably hydraulically pilot-controlled. The reversing valve has an opening pressure of between 1 bar and 10 bar, in particular between 1.5 bar and 5 bar, and particularly preferably of about 2 bar within the usual tolerance range. As a result, the pressure loss remains low. Further preferably, the reversing valve is designed for an operating pressure of between 200 bar and 450 bar, preferably between 300 bar and 450 bar, and in particular between 350 bar and 420 bar. Preferably, the pilot valve is designed for an operating pressure of up to 500 bar. Finally, preferably, the valve device is designed for a flow rate (volume flow) of 500 liters per minute (l / min) to 2500 l / min, the flow rate being in particular 600 l / min to 1500 l / min and particularly preferably 700 l / min to 1350 l / min.

[0046] The valve device is preferably designed in a modular manner, so that, for example, one directional valve can be mounted on one side of the cantilever and another directional valve can be mounted on another side of the cantilever, regardless of the specific form of the valve device.

[0047] An embodiment is particularly advantageous in which the reversing valve of the valve device can be connected directly to a shutoff valve or a quick-change connection of the work machine or can even replace the shutoff valve or quick-change connection. In the area of ​​the boom of an excavator, a ball valve is usually installed, which must be closed in order to change the auxiliary equipment. Instead of the ball valve, the valve device according to the invention can be installed, so that here, when the excavator is shut down, additional benefits are obtained by automatically closing the valve and working time is saved, while the operating safety is increased.

[0048] It is conceivable that the directional control valve is closed by operating the emergency shut-off switch and reopened by operating the emergency switch again after the leakage has been eliminated. However, the directional control valve can also be automatically controlled by a sensor that detects the pressure relief, or the directional control valve can be fully automatically closed during the pressure relief.

[0049] Preferably, if at least two hydraulic lines of the working machine are located against the upper side of the boom in a protected area or are formed by a channel or a pressure medium pipe, and the corresponding switching valves are arranged in the protected area, the probability of damage to the hydraulic lines on the pressure side of the valve device and to the valve device itself, in particular during removal operation, is reduced. Preferably, the corresponding switching valves or 2 / 2-way valves are integrated in a valve block, which can be flange-mounted on the channel, for example.

[0050] Preferably, the at least two hydraulic lines directly supplying the implement are fixed to the implement at a first fixing point and to the boom assembly at a second fixing point, and a flexible hose elbow is formed between the two fixing points, and the at least one directional valve or 2 / 2-way valve is respectively arranged outside the flexible hose elbow in the region of the boom. The two directional valves are preferably hydraulically and / or electrically connected to each other.

[0051] If the second fastening point of each hose elbow is located on the respectively associated directional valve, additional fittings or passive leak-proof structures can be omitted in this area.

[0052] Preferably, the oil-hydraulic tool is an excavator tool, a demolition shear, a forestry tool or an underground engineering tool. For these tools and the common fields of application there is a particularly high risk of line ruptures due to damage occurring during operation. The safety device described here is particularly advantageous if the substructure is self-propelled.

[0053] The emergency situation which leads to the blocking of the 2 / 2-way valve is advantageously the rupture of at least one hose elbow, in particular a hose elbow directly in the vicinity of the implement mounted on the boom.

[0054] Preferably, such a work machine has a valve device having the features described above.

[0055] Furthermore, a method for protecting a work machine as described above is proposed, which method comprises the following steps which are carried out in sequence:

[0056] a. If a leak occurs in at least one hydraulic line between the oil hydraulic device and the valve, the at least one reversing valve or 2 / 2-way valve moves to a shut-off position (resting position) and thereby shuts off the at least two hydraulic lines,

[0057] b. After the leakage has been eliminated, the at least one directional valve or 2 / 2-way valve is switched into the initial position.

[0058] This effectively limits the amount of oil that can escape in the event of a hydraulic line rupture, while the hydraulic pump of the work machine continues to deliver oil. This prevents damage to the hydraulic pump due to idling. In addition, the method serves to protect against work and can save hydraulic oil (resource conservation).

[0059] The oil hydraulic device can in particular comprise a double-acting hydraulic cylinder, and in step b. the two hydraulic lines connected to the double-acting hydraulic cylinder are blocked.

[0060] The use of the valve device described above in a working machine prevents uncontrolled oil outflow from the hose rupture in the region of the hose elbow of the two working lines in the event of a hose rupture, thereby achieving particularly high reliability in emergency situations while achieving simple control.

[0061] In addition, a mobile hydraulic construction machine is proposed, which has an upper structure, a lower structure, a boom assembly preferably having a boom and an intermediate boom and a boom, an attachment connected to the boom, and a hydraulic system for moving the boom assembly and the attachment. The hydraulic system has at least one pump and an additional valve group, which is designed to be able to adjust the oil flow in at least two hydraulic lines connecting the attachment to the pump in order to control the attachment. Each of the hydraulic lines is respectively equipped with at least one emergency stop valve, which is designed to be able to close the hydraulic line in an emergency, and the at least one emergency stop valve is arranged in the hydraulic line in the area of ​​the boom assembly and / or in the hydraulic line on the flow side of the additional valve group away from the pump in the upper structure. The emergency stop valve can be formed by the valve device described above. The emergency stop valve can also include a shut-off device, such as, for example, a slide valve.

[0062] The emergency stop valve makes it possible to close the hydraulic line in the event of a leak and thereby prevent the hydraulic oil from escaping to the greatest extent possible. It is particularly simple to retrofit the emergency stop valve in the area of ​​the superstructure. It is advantageous to use an emergency stop valve in the area of ​​the boom, since this is particularly helpful if a leak occurs in the area between the boom assembly and the attachment.

[0063] The at least two hydraulic lines are preferably placed against the upper side of the rod in a protected area or formed by a channel, in which the corresponding emergency stop valve is located. "Protected area" means that the hydraulic lines are rigid tubes, in particular made of metal, which are protected against external influences. The protected area is to be distinguished from areas of the hydraulic lines that have flexible hoses, which can quickly tear or become damaged.

[0064] Preferably, the hydraulic line is fixed to the attachment at a first fixing point and to the boom at a second fixing point, and a flexible hose elbow is formed between the two fixing points. Preferably, the at least one emergency stop valve is arranged outside the flexible hose elbow in the area of ​​the boom assembly or the boom, respectively. In normal work with the mobile hydraulic construction machine, oil leaks often occur at the flexible hose elbow, because the hose elbow is prone to getting hooked at locations on the construction site due to its characteristics. However, such a hose elbow is indispensable for the use of construction machinery, because without the hose elbow the boom assembly and the attachment cannot perform large movements. The at least one emergency stop valve is closed, and thus the hydraulic line and the hydraulic system, to prevent further outflow of oil in the event of a leak.

[0065] The emergency stop valve is preferably an electrically controlled solenoid valve, which is particularly economical. The emergency stop valve is a two-way valve. As described above, the hydraulic system preferably comprises at least one return line, which connects the emergency stop valve to a hydraulic oil tank, from which the hydraulic system is supplied by the pump. In this case, no communication with the additional valve group is required, since the flow of hydraulic oil through the hydraulic line does not need to be interrupted in the region of the additional valve group.

[0066] In a further preferred embodiment, the mobile hydraulic construction machine comprises an emergency shutoff actuation device which communicates with the emergency stop valve and / or optionally additionally with the additional valve group and is provided to close the emergency stop valve when actuated.

[0067] The emergency shutdown operating device is preferably arranged in the cab of the mobile hydraulic machine. When the driver of the mobile hydraulic construction machine confirms that there is a leak, the driver can operate the emergency shutdown operating device and thereby prevent the hydraulic oil from continuing to flow out of the ruptured part.

[0068] The at least two hydraulic lines are preferably equipped with at least one sensor, which is configured to detect a leak in the at least two hydraulic lines, the at least one sensor communicating with the emergency stop valve and / or the additional valve group. In this case, the emergency stop valve can be closed automatically in the event of a leak or pressure relief in the hydraulic lines.

[0069] In a preferred embodiment, the mobile hydraulic construction machine is a long boom excavator having a digging height in the range of 15 m to 90 m and in particular a weight class between 25 t and 400 t, but it can also be a mini excavator of up to about 10 t or a mini excavator of up to about 18 t.

[0070] In addition, a method for controlling a mobile hydraulic construction machine is proposed, wherein the mobile hydraulic construction machine has an upper structure, a lower structure, a boom assembly with a boom, an attachment connected to the boom, and a hydraulic system for moving the boom assembly and the attachment, wherein the hydraulic system includes at least one pump and a valve group, in particular an additional valve group, and the mobile hydraulic construction machine also has at least two hydraulic pipelines connecting the attachment to the pump, and the valve group or the additional valve group is connected to the at least two hydraulic pipelines. The method comprises the following steps performed in sequence:

[0071] a) a leak is detected in one of the hydraulic lines between the accessory and the valve block or the additional valve block,

[0072] b) switching at least one emergency stop valve, which is respectively arranged in the area of ​​the boom assembly and / or in the superstructure on the flow side of the valve group or the additional valve group away from the pump, and thereby shutting off the at least two hydraulic lines.

[0073] The emergency stop valve is preferably a two-way valve and the hydraulic system comprises at least one oil return line, and the following operations are set in step b) of the method:

[0074] - The hydraulic line is connected to the oil return line via the emergency stop valve, the oil return line is connected to a hydraulic oil tank, and the hydraulic oil tank supplies the hydraulic system via the pump.

[0075] Preferably, the method comprises the following steps between steps a) and b):

[0076] The valve group or the additional valve group is actuated and the at least two hydraulic lines are thereby blocked, after which step b) is carried out with a predetermined time delay.

[0077] Preferably, the method comprises detecting by observation by an operator or by a sensor arranged in the hydraulic line.

[0078] Preferably, the mobile hydraulic construction machine comprises an emergency shut-off operating device which communicates with the emergency stop valve and / or the valve group or the additional valve group, and the method comprises the following method steps after step a):

[0079] - The emergency shut-off operating device is manually operated by an operator.

[0080] The mobile hydraulic construction machine can be designed as described above.

[0081] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0082] Figure 1 A perspective view showing a mobile hydraulic construction machine,

[0083] Figure 2 Show Figure 1 A top view of a mobile hydraulic construction machine in

[0084] Figure 3 Show Figure 1 A schematic diagram of an embodiment of a hydraulic system for an attachment of a mobile hydraulic construction machine,

[0085] Figure 4 A schematic diagram showing another embodiment of a hydraulic system for an attachment,

[0086] Figure 5 The valve device of one embodiment is shown in the blocking position, and

[0087] Figure 6 A further embodiment of a valve arrangement is shown in the blocked position.

[0088] Figure 1 A mobile hydraulic construction machine 1 as a long boom excavator is shown according to a preferred embodiment, which has a substructure 2, which is connected to an upper structure 4 via a swivel mechanism 3 that can rotate about an axis of rotation S. By means of the swivel mechanism 3, a controlled swivel movement can be performed between the upper structure 4 and the substructure 2 about the axis of rotation S. In general, a distinction can be made between tire excavators and crawler excavators. The substructure 2 can have tires in the travel mechanism on the one hand, i.e. the tire excavator in question, which is suitable for weight classes up to 25 t, and on the other hand, the substructure can have tracks, i.e. the crawler excavator in question, which is suitable for all weight classes. Tire and crawler excavators are distinguished from other excavator types, such as dredgers, as self-propelled land vehicles. In this preferred embodiment, the long boom excavator 1 is implemented as a crawler excavator, which is generally suitable for weight classes between 25 t and 400 t that are common in demolition work. The superstructure 4 has a cab 5 at its end in the direction of travel F (straight ahead) and a counterweight 6 opposite the cab 5. Figure 1 and 2A three-section boom assembly 7 can be seen, which is fixed to the superstructure 4 beside or behind the cab 5. The boom assembly 7 has three sections 8, 9, and 10 arranged in sequence one after the other. The first section 8 is called the boom, the second section 9 is called the intermediate boom, and the third section farthest from the superstructure is called the boom 10, and the two sections arranged in sequence one after the other are rotatably supported by each other through a pin. The boom assembly 7 also includes a boom cylinder 11 and an intermediate boom cylinder 12, which can move the first section 8 and the second section 9 of the boom assembly 7. In addition, a boom cylinder 22 is provided, which can drive the boom 10 to move. An attachment 14 is fixed to the free end of the boom 10 through which the boom head pin 13 passes. This connection can preferably be established by a speed changer. The attachment 14 and the speed changer can also rotate around the rotation axis defined by the boom head pin 13. The attachment 14 is a gripper in this embodiment, but any hydraulic attachment, such as a scissors fork, can also be used.

[0089] The mobile hydraulic construction machine 1 includes a hydraulic system, which mainly uses hydraulic oil to drive the boom cylinder 11 and the intermediate boom cylinder 12 as well as the arm cylinder 22. The hydraulic oil flow and the movement caused by it are controlled and monitored by the main valve group of the hydraulic system, not shown, located in the upper structure 4. The main valve group includes a plurality of valves for adjusting the hydraulic oil supply to one of the hydraulic cylinders. In addition, the main valve group is also responsible for controlling the rotation drive of the rotating mechanism 3 and the hydraulic travel drive for the crawler tracks of the lower structure 2. In addition, the hydraulic system also includes an additional valve group 15, a hydraulic oil tank 16 and a hydraulic pump 17 located in the upper structure 4. The hydraulic pump 17 delivers hydraulic oil of the hydraulic system and is connected to the main valve group and the additional valve group 15 via a hydraulic connection structure. If the power of one pump is insufficient for the necessary use or the system is to be constructed redundantly, multiple pumps can be used in the hydraulic system. The additional valve group 15 controls and regulates the hydraulic oil flow sent to the attachment 14. The hydraulic pipeline 18 leads from the additional valve group 15 to the attachment 14. In Figure 1Only one hydraulic line 18 is shown, but multiple, but at least two hydraulic lines 18 can be used, depending on the attachment used and the type of construction machine. The type of attachment 14 and the movements that the attachment can perform define the number of hydraulic lines 18 (used and connected). The hydraulic lines 18 are formed in the region of the pins 19 of the boom assembly 7, i.e. between the superstructure 4 and the first segment 8 and between the first segment 8 and the second segment 9 and between the second segment 9 and the boom 10 by flexible hose lines arranged in an arc, which are also called boom hose elbows 20. A flexible hose elbow 21 is also formed between the first fixing point on the attachment 14 and the second fixing point on the boom 10. The flexible boom hose elbow 20 and the flexible hose elbow 21 make it possible for the individual segments of the boom assembly 7 to be able to rotate about the longitudinal axis of the pins 19 without interrupting or breaking the hydraulic lines 18. The hose elbow 21 and the boom hose elbow 20 are formed for each additional hydraulic line 18 not shown here. The part of the hydraulic line 18 that extends centrally along the sections of the boom assembly 7 away from the axis of rotation or the pin 19 is realized by a rigid metal pipe. The ends of the metal pipe are respectively connected to flexible hose lines to form the hydraulic line 18. The metal pipe forms a protected area in which the hydraulic line 18 is protected from damage from the outside. In the hydraulic line 18 shown, two emergency stop valves 23, 24 are provided between the additional valve group 15 and the attachment 14. The emergency stop valves 23, 24 of the at least two hydraulic lines 18 are divided into a first emergency stop valve 23 and a second emergency stop valve 24, and are Figure 1 Schematically shown as a rectangle in the figure. The first emergency stop valve 23 and the second emergency stop valve 24 can close the corresponding hydraulic pipeline 18 at the corresponding position. It can be ensured that the emergency stop valves 23, 24 located on the side of the additional valve group close to the oil leakage that has occurred can prevent the hydraulic oil in the hydraulic pipeline 18 between this emergency stop valve 23, 24 and the hydraulic pump 17 or the hydraulic oil tank 16 from flowing out. The first emergency stop valve 23 is arranged in the hydraulic pipeline 18 in the upper structure 4 on the flow side of the accessory valve group 15 away from the pump. The second emergency stop valve 24 is arranged in the hydraulic pipeline 18 outside the hose elbow 21 in the area of ​​the boom 10. In particular, as Figure 1As shown, a preferred position is one in which the position is located in the region of the boom head pin 13 directly before or after the flexible hose line in the flow direction. According to experience, the hose line usually leaks in the region of the boom head pin 13. The second emergency stop valve 24 located in the aforementioned position can keep the maximum possible amount of hydraulic oil in the hydraulic line 18 in the event of such a leak. If oil leaks in the hose elbow 21, the oil in the hydraulic line 18 can be kept in the hydraulic line 18 between the second emergency stop valve 24 and the additional valve group 15 by closing the second emergency stop valve 24 and preventing it from flowing out. It is conceivable to use additional emergency stop valves, which, for example, provide protection against leakage of the boom hose elbow 20 of the second section 9. Each hydraulic line 18 requires at least one emergency stop valve 23, 24. Even if the first emergency stop valve 23 leaks in the flexible hose line in the region of the boom head pin 13, it can prevent a large amount of hydraulic oil from flowing out. The emergency stop valves 23, 24 are clearly different from conventional pipe break protection devices, which are currently installed as standard in mobile hydraulic construction machines. The pipe break protection device, not shown, is installed on the attachment 14 and prevents uncontrolled movement of the attachment 14 in the event of a pipe break, in order to protect the operator and construction site personnel. The pipe break protection device maintains the pressure of the hydraulic oil in the working chamber of the hydraulic cylinder in the attachment 14 or installed in the attachment, and the attachment 14 can be kept in a fixed position. The emergency stop valves 23, 24 interrupt the hydraulic system at at least one point toward the additional valve group 15. The hydraulic oil in the hydraulic line between the break and the emergency stop valves 23, 24 flows out. However, the emergency stop valves 23, 24 prevent a large amount of hydraulic oil from flowing out, and thus contribute to environmental protection during demolition work.

[0090] Figure 3 A part of the hydraulic system, which is only shown schematically, is used in particular for controlling the movement of the attachment 14. The hydraulic valves of the additional valve group 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 group 15 with the necessary oil pressure in order to control the attachment 14 or its hydraulic cylinder. The additional valve group 15 is used to regulate the volume flow of the hydraulic oil through a total of four hydraulic lines 18 shown by way of example, and thus the movement of the attachment 14 can be controlled. For each hydraulic line 18, there is a first emergency stop valve 23 and a second emergency stop valve 24. The first emergency stop valve 23 and the second emergency stop valve 24 are respectively located in two different sections of the hydraulic line 18. Here it is shown at the flexible hose elbow 21 in the area of ​​the boom hose elbow 20 and the boom head pin 13 closest to the additional valve group.

[0091] On the one hand, in the superstructure 4, a first emergency stop valve 23 is arranged in a section of the corresponding hydraulic line 18 located on the flow side of the additional valve group 15 away from the pump, and on the other hand, a second emergency stop valve 24 is arranged in a boom assembly section of the corresponding hydraulic line 18, which is located outside the superstructure 4 and in the area of ​​the boom 10 outside the flexible hose elbow 21, as already explained above. The emergency stop valves 23, 24 are open during normal operation of the mobile hydraulic construction machine 1, so that the hydraulic oil can flow through the emergency stop valves 23, 24 without hindrance. The emergency stop valves 23, 24 are controlled by an emergency closing operating device 25. When the emergency closing operating device 25 is operated, the hydraulic line 18 is closed by the emergency stop valves 23, 24 to stop the hydraulic oil flow. The emergency stop operating device 25 communicates electrically with the additional valve group 15 to switch the emergency stop valves 23, 24.

[0092] After a leak is detected in one of the hydraulic lines 18 between the attachment 14 and the additional valve block 15, the emergency stop valves 23, 24 can be switched and the hydraulic line 18 can be blocked. Figure 3 2 and 3 respectively show the closed states of the emergency stop valves 23 and 24 , which can be achieved by operating the emergency closing operating device 25 .

[0093] In a preferred embodiment, the emergency stop valves 23 and 24 are electrically controlled solenoid valves.

[0094] In a preferred embodiment, the operator finds the leakage and operates the emergency shutdown operating device 25 accordingly, so that the emergency stop valves 23 and 24 are switched and the hydraulic pipeline 18 is cut off. The detection can also be performed by a sensor assigned to the hydraulic pipeline 18, so that the emergency shutdown operating device 25 can be automatically operated at this time.

[0095] In a preferred embodiment, the additional valve group 15 is first controlled by operating the emergency shutdown operating device 25, and the at least two hydraulic lines 18 are blocked by the additional valve group 15. Thereafter, the emergency stop valves 23, 24 are switched and the hydraulic lines 18 are closed with a predeterminable time delay.

[0096] Figure 4 Shows most of the Figure 3 Another embodiment of a part of a similar hydraulic system. The attachment 14 is in this case hydraulically piloted via a low-pressure line. The boom hose elbow 20 and the hose elbow 21 are not shown here. The differences are explained below. Figure 4In the embodiment shown in FIG. 1 , the first emergency stop valve 23 is implemented in the upper structure section of the hydraulic line 18 by a two-way valve 26, which can be connected to the hydraulic oil tank 16 of the hydraulic system via a return line 27. In one embodiment, during normal operation, the second emergency stop valve 24 in the boom assembly section by an electrically controlled solenoid valve is open, and the two-way valve 26 in the upper structure section allows hydraulic oil to flow from the additional valve group 15 to the attachment 14 via the hydraulic line in the first switching position.

[0097] After oil leakage is detected by an operator or a sensor, the emergency shutdown operating device 25 is operated to switch and close the second emergency stop valve 24 in the boom assembly section of the hydraulic pipeline 18, and switch the two-way valve 26 to the second switching position shown. In the second switching position, hydraulic oil flows from the additional valve group 15 into the hydraulic oil tank 16 via the return oil pipeline 27.

[0098] It is conceivable that more than two emergency stop valves 23 , 24 may be used per hydraulic line 18 .

[0099] In the two embodiments of the hydraulic system, one is an electrical pilot control and the other is a hydraulic pilot control, in which the detection of oil leakage can be carried out by an operator or a sensor. The emergency shutdown operating device 25 can be formed, for example, by an operating button located in the cab 5 or on the boom assembly 7 or can be accessed via a controller of the mobile hydraulic construction machine 1, which has the necessary operating elements for controlling the mobile hydraulic construction machine 1.

[0100] By operating the emergency closing operating device 25, the emergency stop valves 23 and 24 are switched and the flow of hydraulic oil is stopped. By re-operating the emergency closing operating device 25, the emergency stop valves 23 and 24 can be switched and reset to reopen the hydraulic pipeline 18 leading to the attachment 14. When the oil leakage on the hydraulic pipeline 18 has been eliminated, the switching and resetting of the emergency stop valves 23 and 24 are performed. When a leak is detected by a sensor, it is conceivable that an alarm can be output, based on which the operator can operate the emergency closing operating device 25. However, the emergency stop valves 23, 24 and / or the additional valve group 15 can also be automatically operated by a sensor that detects a pressure drop. In another embodiment, an emergency stop valve that automatically closes when the pressure in the hydraulic pipeline 18 drops can be set.

[0101] Finally Figure 5, a valve device with two emergency stop valves is shown. The valve device comprises: a first 2 / 2-way valve 30, which is connected to the first pressure line P1 and the first working line A1; a second 2 / 2-way valve 31, which is connected to the second pressure line P2 and the second working line A2; a 2 / 4-way valve 32, which here forms a component with the second 2 / 2-way valve 31 and is connected to the pressure supply line Pa, the pressure relief line T, the first control line C and the cut-off interface D; and a shuttle valve 33, which has a first inlet 34 that can be cut off, a second inlet 35 that can be cut off, and an outlet 36. The 2 / 2-way valve is an emergency stop valve of the form described above and can be installed and used accordingly.

[0102] The 2 / 4-way valve 32 can be electrically operated via an electrical conductor 37 and Figure 5 In the rest position shown in FIG, the supply pressure line Pa is connected to the first control line C and the pressure relief line T is connected to the permanently blocked (normally closed) port D of the 2 / 4-way valve 32. In the electrically operated position, the supply pressure line Pa is connected to the permanently blocked port D and is thus blocked. The control line C is connected to the pressure relief line T to be substantially depressurized thereby.

[0103] The control line C is connected to the first 2 / 2-way valve 30 and the second 2 / 2-way valve 31 , so that when the control line C is pressurized, the 2 / 2-way valves can be pilot-controlled into a closed position.

[0104] The 2 / 2-way valve 30 and the 2 / 2-way valve 31 are preloaded into the closed position (NC) by a spring 39 in the illustrated static state. The two valves are controlled by the supply pressure in the connecting line P1 or P2 and the working line A1 or A2. For this purpose, a pilot control line 40 is provided in the 2 / 2-way valve 30, which extends from the pressure line P1 to a working chamber (not shown) opposite the spring 39, and a further pilot control line 41 extends from the working line A1 to the same working chamber. The geometric design of the spring 39 and the movable valve element and the working chamber (not shown) is selected so that the 2 / 2-way valve 30 is switched into the open position against the force of the spring 39 at a supply pressure of approximately 2 bar. In this way, no electrical actuation of the directional control valve 30 is required and is not provided. The directional control valve is purely pressure-controlled. The same applies to the 2 / 2-way valve 31, in which the pilot control line 42 extends from the pressure line P2 and the pilot control line 44 from the working line A2 to the corresponding working chamber. This valve is also pressure-controlled and is set to open, for example, when a supply pressure of 2 bar is applied.

[0105] That is to say, in Figure 5In the rest position shown in FIG. 1 , both 2 / 2-way valves 30 and 31 are closed. If pressure builds up in the pressure line P1 or P2, the corresponding 2 / 2-way valve is pilot-controlled into the open position via the pilot control line 40 or 43. At the same time, however, a higher pressure is applied to the outflow 36 of the shuttle valve 33 via the connection 34 or 35 of the shuttle valve 33, respectively, which then acts on the pressure supply line Pa and is applied to the control line C via the 4 / 2-way valve 32 in the rest position, which in turn conducts the higher pressure to the spring side of the 2 / 2-way valve 30 or 31 and thereby pilot-controls the movable valve element of the 2 / 2-way valve 30 or 31 into the closed position. The corresponding control surfaces of the 2 / 2-way valves 30 and 31 are dimensioned so that the 2 / 2-way valve 30 or 31 remains closed when the same pressure is present in the control line C and the pilot control line 40 or 43.

[0106] In order to start the operation of the working machine from this current position of the valve arrangement with the hydraulic device 47 connected to the working lines A1 and A2, an operating voltage of, for example, 24 V is applied to the electrical line 37, in which the normally closed emergency stop switch 45 is connected in series. As a result, the 4 / 2-way valve 32 is switched to the working position in which the control line C is connected to the pressure relief line T and the pressure supply line Pa is connected to the blocked connection D.

[0107] If pressure is now applied to the pressure line P by the hydraulic system of the working machine, for example, the corresponding pressure is applied to the 2 / 2-way valve via the pilot control line 40. The shuttle valve 33 now directs this pressure to the outflow port 36 and the pre-pressure line Pa as described above, but in the 2 / 4-way valve 32 this pre-pressure line is switched to the connection D and is thus blocked. The control line C is connected to the pressure relief port T and is therefore pressure-free. As a result, there is no pressure in the control line C that can counteract the opening of the 2 / 2-way valve 30. The 2 / 2-way valve 30 is switched to the open position. A return flow is formed from the hydraulic device 47, which leads to a pressure increase in the working line A2. This pressure increase causes the 2 / 2-way valve 31 to open via the pilot control line 44, so that the valve device described so far is hydraulically conductive and the hydraulic device 47 can operate in the usual manner.

[0108] The corresponding statements apply to the reverse case. If the pressure line P2 is initially acted upon by hydraulic pressure, first the 2 / 2-way valve 31 opens and then the pressure increase in the working line A1 causes the 2 / 2-way valve 30 to also open.

[0109] The valve device can be fixed, for example, on the boom or arm of the excavator. The pressure lines P1 and P2 can be fixedly installed on the boom or arm as hard lines and connected to the valve device. The valve devices can be constructed as valve groups / valve blocks respectively. Here, the valve groups are preferably fixed on one side of the boom or arm respectively. This is, for example, the position where a ball valve is usually installed. Flexible hose elbows 48 and 49 extend from the valve device to the hydraulic device 47, and the hose elbows can be omitted for movable hydraulic devices. If, as described in detail above, during operation, the hose elbows 48, 49 are hooked on protruding steel bars, for example when dismantling a building, and are thereby torn, a large amount of hydraulic oil will flow out of the ruptured area in a conventional hydraulic system. In this case, the operator of the operating machine can operate the emergency shutdown switch 45, thereby switching the two-position four-way valve 32 without electricity. At this time, the result is achieved in Figure 5 . When the pressure in the hydraulic line drops below the opening pressure of the 2 / 2-way valve due to leakage, the valve closes automatically. Any hydraulic pressure generated by the hydraulic system in the pressure line P1 or P2 is now present at the shuttle valve 33. The higher of the two pressures is applied to the outflow port 36 and transmitted to the control line C. The control line C now brings the 2 / 2-way valve 30 or 31 into the closed position together with the spring force of the spring 39. The result that can be achieved is that in the event of a rupture in the hose elbows 48, 49 and the actuation of the emergency switch 45, the hydraulic system can be completely closed in the valve device so that no further hydraulic fluid can flow out of the hydraulic system.

[0110] It should be emphasized here that the valve device does not replace the function of a conventional hose rupture protection structure, which can be additionally arranged directly on the two connections of the hydraulic device 47 in order to prevent, for example, a cantilevered or suspended load from suddenly falling when the hose elbow 48, 49 ruptures. Such a hose rupture protection structure automatically responds to high volume flows that exceed a specified limit value. This protection structure is basically an automatic volume flow control non-return valve. However, the non-return valve cannot prevent a large amount of hydraulic fluid from escaping from the hydraulic system itself when the hose elbow 48, 49 ruptures in the case of a hose rupture.

[0111] The 2 / 2-way valves 30 and 31 can be of identical construction, but are preferably selected so that one has a larger opening cross section than the other, in order to adapt to different volume flows, for example in double-acting hydraulic devices.

[0112] Figure 6Another schematic diagram of a valve device with an emergency stop valve is shown. A double-acting hydraulic cylinder 50 of a hydraulic load has two chambers. A first chamber 51 is connected to a first working line 52. A second chamber 53 is connected to a second working line 54. The two working lines 52, 54 are connected to a volume control valve not shown on one side of the superstructure, which controls the volume flow through the working lines 52, 54. The volume control valve can be part of an additional valve group. The valve device shown includes a first two-position two-way valve 55, which has a port P connected to a first pressure line 56 and a port A connected to the first working line 52. In the first position of the two-position two-way valve 55, the oil flow from the port A to P and from the port P to A is cut off. In the second position, the valve 55 allows free oil flow from A to P and vice versa from P to A. The two-position two-way valve 55 is preloaded by a spring 57 in the first position (resting position, closed position) shown. The two-position two-way valve 55 has a control line 58, which is connected to a pilot valve 59. The control line 58 is connected to a working chamber (shown by a rectangle) located on the side where the spring 57 is located. According to the specific technical implementation, the spring 57 can be located in the working chamber. The two-position two-way valve 55 is also controlled by the supply pressure in the first pressure line 56 and the first working line 52. For this purpose, a pilot control line 60 is provided in the two-position two-way valve 55, which extends from the first pressure line 50 to the working chamber opposite to the spring 57. This is a schematic diagram. The pilot control line 60 can be the active surface of the piston of the reversing valve. Another pilot control line 61 extends from the first working line 52 to the same working chamber. Here, the active surface of the reversing valve can also be connected to the first working line to form a schematically shown function. The geometric design of the spring 57 and the movable valve element is selected such that the 2 / 2-way valve 55 switches into the open position against the force of the spring 57 at a supply pressure of approximately 2 bar in the first working line 52 or the first pressure line 56. In this way, no electrical actuation of the 2 / 2-way valve 55 is required and is not provided. The 2 / 2-way valve is purely pressure-controlled. The 2 / 2-way valve 55 can be switched into the second, closed position by actuation via the control line 58. The closing pressure of the spring can be approximately 4-6 bar, preferably 2 bar.

[0113] The pilot valve 59 connected to the control line 58 can be configured as a two-position three-way valve. However, it is also conceivable that a two-position four-way valve can be used. Shown here is a two-position three-way valve with a first interface A1 in a first position, which is switched to a virtual position / reactive state (blind) and connected to a pressure relief line 62. The second interface A2 is connected to a control line 63, which controls a second two-position two-way valve 64 and is connected to the control line 58 of the first two-position two-way valve 55 in a branch. Thus, the two two-position two-way valves 55, 64 are controlled by the second interface A2. The second two-position two-way valve 64 is similarly constructed to the first two-position two-way valve 55 and is arranged between the second pressure line 65 and the second working line 54. The control line 63 of the second two-position two-way valve 64 acts similarly in the direction of action of the spring, and when the control line 63 is loaded with pressure, the valve 64 is switched to a closed position.

[0114] The third port A3 of the pilot valve 59 is connected to the supply pressure line 66. In the first position of the 2 / 3-way valve, hydraulic oil flow from port 3 to port 2 is allowed to pass. The control line 63 is loaded with the hydraulic oil pressure from the supply pressure line 66. In the second position of the 2 / 3-way valve, port 3 is switched to the virtual position and hydraulic oil flow from port 2 to port 1 is allowed to pass. Pressure is released in the control line 63 and thus also in the control line 58, and hydraulic oil flows out into the pressure relief line 62. The pilot control valve 59 is preloaded into the first position by a spring. The pilot control valve 59 can be electrically operated by an electrical conductor 67. A normally closed emergency stop switch 68 is connected in series in the electrical conductor 67, and an operating voltage of, for example, 24V is loaded to the emergency stop switch. As a result, the pilot valve 59 is switched to a working position in which the control line 63 is connected to the pressure relief line 62 and the supply pressure line 66 (also called the preload line) is connected to the blocked port A3. Furthermore, the pilot control valve 69 has an optional emergency operating device, which is designed such that the pilot control valve 59 can be switched into the working position by operating the emergency operating device.

[0115] Figure 6 , a first position of the pilot valve 59 is shown, which is not the working position.

[0116] That is to say, in Figure 6In the rest position shown in FIG, both 2 / 2-way valves 55 and 64 are closed. If pressure builds up in the pressure line 56 or 65, the corresponding 2 / 2-way valve 55, 64 is piloted into the open position via the corresponding pilot control line 60 or 69. At the same time, however, the highest pressure applied via the supply pressure line 66 to a total of four ports A1, A2, P1, P2 of the two 2 / 2-way valves acts on the port A2 of the pilot valve 59 and thus on the control lines 58, 63, which in turn conduct this higher pressure to the spring side of the 2 / 2-way valves 55 and 64 and thus pilot the movable valve elements of the 2 / 2-way valves 55 and 64 into the closed position. The respective control surfaces of the 2 / 2-way valves 55 and 64 are dimensioned such that the 2 / 2-way valve 55 or 64 remains closed when the same pressure prevails in the control line 58 , 63 and the pilot control line 60 , 61 or 69 , 70 .

[0117] For this purpose, the supply pressure line 66 is connected to the two working lines 52, 54 and the two pressure lines 56, 65. A branching off of the four lines 52, 54, 56, 65 is provided in parallel, in each of which a non-return valve 71 is provided, which opens in the direction of the supply pressure line 66 when a correspondingly high pressure is applied. If, for example, the pressure line 56 is acted upon by the highest pressure, the non-return valve 71 in the line branching off from the pressure line 56 opens, and the non-return valve 71 connected in parallel therewith closes as a result, since the pressure prevailing there is lower. As explained above, the hydraulic oil pressure of the pressure line 56 is conducted into the supply pressure line 66 and this pressure is provided to the control lines 63, 58.

[0118] In order to start the operation of the working machine from this position of the valve device with the hydraulic load 50 connected to the working lines 52 and 54, the operating voltage is applied to the electrical line 67 and the 3 / 2-way valve 59 is switched to the working position. If pressure is now applied to the pressure line 56 by the hydraulic system of the working machine, for example, the 2 / 2-way valve 55 arranged in this line is acted upon by the pilot control line 60 with the corresponding pressure. As described above, the non-return valve 71 assigned to the pressure line now transmits this pressure to the supply pressure line 66, which, however, is switched to the connection A3 in the pilot valve 59 and is thus blocked. The control line 63 is connected to the pressure relief line 62. In order to depressurize the control line, the pressure relief line 62 is connected to the two working lines 52, 54 and the two pressure lines 56, 65. Branches to the four lines 52, 54, 56, 65 are arranged in parallel, in each of which a non-return valve 71 is arranged, which opens in the direction of the corresponding one of the four lines 52, 54, 56, 65 when a correspondingly higher pressure is applied. If, for example, a higher pressure is applied to the pressure relief line 56 than in the pressure line 65, the non-return valve 71 in the line branching off from the pressure line 65 opens and the pressure in the control lines 63, 58 can be reduced, so that at least a lower pressure exists in the control lines 63, 58 than in the working line 56, which pressure counteracts the opening of the 2 / 2-way valves 55, 64. If, for example, a return flow is generated from the hydraulic consumer 50, the return flow leads to a pressure increase in the working line 54. This pressure increase causes the 2 / 2-way valve 64 to open via the pilot control line 70, so that the valve arrangement described hereto is hydraulically conductive and the hydraulic consumer can be operated in a conventional manner.

[0119] The corresponding description also applies to the reverse situation. If hydraulic pressure is first applied to the pressure line 65, the 2 / 2-way valve 64 first opens, and then due to the pressure increase in the working line 52, the 2 / 2-way valve 55 also opens.

[0120] The valve device can be fixed, for example, on the superstructure of the mobile working machine, or in the case of an excavator, on the boom or the stick. The pressure lines 56 and 65 can now be fixedly mounted on the boom or the stick as hard lines and connected to the valve group. The valve devices can be configured as valve groups respectively. Preferably, the valve groups are respectively fixed on one side of the boom or the stick. This is, for example, the position where a ball valve is usually installed. It is also conceivable that the valve device is arranged in the superstructure. Depending on how the hydraulic load is constructed, one or more working lines are provided. The hydraulic load can also be, for example, a boom cylinder 11, an intermediate boom cylinder 12 or a stick cylinder.

[0121] The flexible hose elbow 50 extends from the valve device in an arc shape to the hydraulic load 50. These areas are called flexible hose elbows and are different from hard pipe elbows that can be obtained as components and have a fixed, rigid geometry. Such flexible hose elbows are indispensable for movable hydraulic devices. If, as described in detail above, during operation, the hose elbow hooks onto protruding steel bars, for example when dismantling a building, and is thereby torn, in a conventional hydraulic system a large amount of hydraulic oil will flow out of the ruptured area. In this case, the operator of the operating machine can operate the emergency shut-off switch 68 and thereby switch the pilot valve 59 without electricity. At this time, entering Figure 6 . If the pressure in the hydraulic line drops below the opening pressure of the 2 / 2-way valve due to a leak, the valve closes automatically. The higher of the two pressures in the pressure line 56 or 65 and the leak-free working line acts on the supply pressure line 66 and is transmitted to the control lines 58, 63. The control lines 58, 63 now bring the 2 / 2-way valves 55, 64 together with the spring force of the spring 57 into the closed position. This has the result that in the event of a leak in the working line, for example in the event of a rupture in a flexible hose elbow and the actuation of the emergency switch 68, the hydraulic system can be completely closed in the valve arrangement so that no more hydraulic fluid can flow out of the hydraulic system.

[0122] It should be emphasized here that the valve device does not replace the function of a conventional hose rupture protection structure, which can be additionally arranged directly on the two connections of the hydraulic device 50 in order to prevent, for example, cantilevered or suspended loads from suddenly falling down in the event of a hose elbow rupture. Such hose rupture protection structures automatically respond to high volume flows that exceed a specified limit value. Such protection structures are essentially automatic volume flow-controlled non-return valves. However, in the event of a hose rupture, the non-return valve cannot prevent a large amount of hydraulic fluid from escaping from the hydraulic system itself when a hose elbow ruptures.

[0123] The 2 / 2-way valves 55, 64 can be of identical construction, but are preferably selected so that one of the 2 / 2-way valves has a larger opening cross section than the other 2 / 2-way valve in order to adapt to different volume flows, for example in double-acting hydraulic devices or backflow-sensitive auxiliary devices (e.g. hydraulic hammers).

Claims

1. A valve device for a mobile working machine (1) having a hydraulic load (47, 50), the valve device comprising: at least one reversing valve (30, 31, 55, 64), which is connected to a pressure line (P1, P2, 56, 65) and a working line (A1, A2, 52, 54) of a hydraulic load (47, 50), and comprises a hydraulic control line (C, 58, 63) which is designed to switch the at least one reversing valve (30, 31, 55, 64) to a first position, - a pilot valve (32, 59), which is connected to the hydraulic control line (C, 58, 63), - Supply pressure line (Pa, 66), and -Pressure relief line (T, 62), wherein: The pilot valve (32, 59) is designed to connect the hydraulic control line (C, 58, 63) alternately to a pressure supply line (Pa, 66) and a pressure relief line (T, 62).

2. The valve device according to claim 1, characterized in that The first position of the at least one reversing valve (30, 31, 55, 64) is a closed position and blocks the flow of oil in both directions.

3. A valve device according to any one of the preceding claims, characterized in that The at least one reversing valve (30, 31, 55, 64) is preloaded into a first position by a spring and has two pilot control lines (40, 41, 43, 44, 60, 61, 69, 70), the pilot control lines being connected to a working chamber opposite to the spring (39, 57), the first pilot control line (40, 43, 60, 69) being connected to the pressure line (P1, P2, 56, 65), and the second pilot control line (41, 44, 61, 70) being connected to the working line (A1, A2, 52, 54).

4. A valve device according to any one of the preceding claims, characterized in that The pilot valve (32, 59) is a two-position three-way valve or a two-position four-way valve.

5. The valve device according to any one of the preceding claims, characterized in that The pilot valve (32, 59) is electrically operable and is capable of connecting the supply pressure line (Pa, 66) to the hydraulic control line (C, 58, 63) in a static position, and is capable of connecting the hydraulic control line (C, 58, 63) to the pressure relief line (T, 62) in a control position.

6. A valve device according to any one of the preceding claims, characterized in that The pilot valve (32, 59) is electrically actuated in the operating position and can be switched electrically free by means of an emergency shut-off switch (45, 68).

7. The valve device according to claim 6, characterized in that The emergency shutoff switch (45, 68) is manually operable and is arranged in a working cabin of the working machine.

8. A valve device according to any one of the preceding claims, characterised in that The valve device comprises a first reversing valve (30, 55) and a second reversing valve (31, 64), wherein the first reversing valve and the second reversing valve are respectively connected to a pressure line (P1, P2, 56, 65) and a working line (A1, A2, 52, 54) of a common hydraulic load (47, 50), and each of the hydraulic control lines (C, 58, 63) are connected to each other so that when the hydraulic control lines are loaded with pressure, the hydraulic control lines (C, 58, 63) can pilot control the two reversing valves to a closed position.

9. The valve device according to claim 8, characterized in that The valve device comprises a shuttle valve (33), the shuttle valve having a first shutoff inlet (34), a second shutoff inlet (35) and an outlet (36), the first shutoff inlet (34) of the shuttle valve being connected to a first pressure line (P1) of a first reversing valve (30), the second shutoff inlet (35) of the shuttle valve being connected to a second pressure line (P2) of a second reversing valve (31), and the outlet (36) of the shuttle valve being connected to a supply pressure line (Pa), and the shuttle valve (33) being configured so that the pressure lines (P1, P2) can be connected to the supply pressure line (Pa) at a maximum pressure.

10. The valve device according to any one of the preceding claims 1 to 8, characterized in that The pressure supply line (66) is connected to the pressure lines (56, 65) and the working lines (52, 54) via branches, the branches being connected in parallel and each having a check valve (71), the check valve being arranged so as to be able to direct the highest pressure existing in the lines (52, 54, 56, 65) toward the pressure supply line (66).

11. Valve device according to any one of the preceding claims, characterized in that The pressure relief pipeline (T) is a fuel tank pipeline that can be connected to a fuel tank.

12. The valve device according to any one of the preceding claims 1 to 10, characterized in that The pressure relief line (62) is connected to the pressure line (56, 65) and the working line (52, 54) via branches, the branches being connected in parallel and each having a non-return valve (72) which can open towards one of the lines (52, 54, 56, 65) with a lower pressure when the pressure present in the pressure relief line (62) is applied.

13. A valve device according to any one of the preceding claims, characterised in that The first reversing valve (30, 55) and / or the second reversing valve (31, 64) is a 2 / 2-way valve.

14. Use of a valve device according to any of the above claims in a working line of a hydraulic load (47, 50) in a mobile working machine so that when a leak occurs in the working line (52, 54, A1, A2), the working line is blocked and the outflow of hydraulic oil from the leak point is prevented to the greatest extent possible.

15. A mobile working machine (1), comprising a substructure (3), an upper structure (4) and a boom assembly (7), and a hydraulic system, the hydraulic system comprising a hydraulic pump (17), a volume control valve (15), a hydraulic load (47, 50) and at least two hydraulic lines (18, 52, 54, 56, 65, A1, A2, P1, P2), the volume control valve being designed to be able to regulate the oil flow through at least one of the hydraulic lines (18, 52, 54, A1, A2) in order to control the hydraulic load (47, 50), characterized in that: At least one of the hydraulic lines (18, 52, 54, 56, 65, A1, A2, P1, P2) has a reversing valve (30, 31, 55, 64), which is designed to close the hydraulic line (18, 52, 54, 56, 65, A1, A2, P1, P2) when a leak occurs in the hydraulic line.

16. The mobile working machine according to claim 15, characterized in that: The reversing valve (30, 31, 55, 64) is arranged between the volume control valve and the hydraulic load (47, 50).

17. The mobile working machine according to claim 15 or 16, characterized in that: The mobile working machine comprises a valve arrangement according to any of the preceding claims, and the changeover valve (30, 31, 55, 64) is part of the valve arrangement.

18. A method for minimizing hydraulic oil losses in a mobile working machine (1) according to any one of claims 15 to 17 when a working line (52, 54, A1, A2) leaks, the method comprising the following steps which are carried out in sequence: a. when a leak occurs in the hydraulic line (52, 54, A1, A2) between the hydraulic load (47, 50) and the reversing valve (30, 31, 55, 64), the reversing valve (30, 31, 55, 64) is moved to the shut-off position, thereby shutting off the hydraulic line (52, 54, A1, A2), b. Ensure that the cut-off position is maintained until the leak is eliminated, c. After the leakage has been eliminated, the switching valve (30, 31, 55, 64) and / or the valve arrangement is switched to an initial state before the leakage.

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