Mobile work machine equipped with an emergency stop function in case of leaks in the operating piping.

Abstract

The present invention relates to a mobile work machine (33) comprising a substructure (34), a superstructure (36), a boom assembly (39), and a hydraulic system. The hydraulic system comprises a hydraulic pump (3), operating pipes (8, 10), a hydraulic load (5), a volume control valve (7) configured to adjust the oil flow in the operating pipes (8, 10) connected to the hydraulic load (5) in order to operate the hydraulic load (5), and bypasses (20, 21) that can bypass the volume control valve (7). A suction device (23) having a supply function is provided in the bypasses (20, 21). When overpressure is applied to the operating pipe (8), the bypass (20) is closed, and when low pressure is applied to the operating pipe (8), the bypass (20) is opened, allowing the operating pipe (8) or the hydraulic load (5) connected to the operating pipe (8) to draw hydraulic fluid through a supply pipe (12). The suction device (23) has an emergency stop function, or the hydraulic system includes an emergency stop device (32) which closes the piping in the bypass (20) or the supply pipe (12) when a leak is detected in the operating piping (8).

Description

Technical Field

[0001] The present invention relates to a mobile working machine having features of the superordinate concept of claim 1, the use of a valve or shut-off device in a mobile working machine having features of the superordinate concept of claim 10, and a method for minimizing the loss of hydraulic oil in a mobile working machine when a leak occurs in the working piping.

Background Art

[0002] Mobile work machines equipped with hydraulic systems, particularly construction machinery, are widely used at construction sites for demolition and removal work. However, such mobile work machines are also used in civil engineering and forestry. Examples of mobile work machines include cranes, excavators (such as loading excavators), and forestry machinery. In the demolition field, so-called long-arm boom excavators (or "long front" excavators) or demolition excavators are used. With their long booms and arms, mobile hydraulic construction machines are excellent tools that can use hydraulic attachments suited to their respective purposes, even at heights exceeding 20 meters. When operating mobile hydraulic construction machines, the hydraulic hoses that make up the hydraulic systems of the attachments and the hydraulic cylinders in the boom are exposed to external factors that can cause damage to the hydraulic hoses due to aging and weather. However, many more unpredictable causes of damage are external mechanical forces on the hydraulic hoses due to work in areas that cannot be fully monitored. Because excavator operators cannot see all parts of the boom of a mobile hydraulic construction machine while it is in operation, hydraulic hoses can be damaged at the construction site by, for example, getting caught on sharp objects, resulting in holes, tears, cuts, or crushing. Due to unavoidable aging and other unpredictable external influences, oil leaks from hydraulic hoses can occur during normal operation of mobile construction machines. European Patent Publication No. 2547912, for example, describes the method of shutting off the hydraulic system piping at the attachment when a pipe breaks, thereby preventing the attachment from moving uncontrollably and remaining stationary, thus avoiding safety risks at the construction site. However, in this case, the hydraulic system is only shut off on the attachment side, which is dangerous. This is because the long booms and arms of mobile hydraulic construction machines also require long hydraulic piping that needs to reach the attachment end of the arm, so if an oil leak occurs, in many cases more than 400 liters of oil will leak out in less than 30 seconds and reach the ground at the construction site.Oil leaks, which often involve high temperatures, not only mean additional costs for replenishing lost oil, but also serious environmental pollution at construction sites and, in many cases, serious dangers to human life.

[0003] The same applies to the use of logging machines in forestry, where some logging machines have a long boom with clamps attached to grip the tree trunk, and are equipped with a hydraulic motor to rotate the clamps in addition to a hydraulic unit for the clamps. [Overview of the project]

[0004] Therefore, the object of the present invention is to provide a mobile work machine in which the hydraulic system is configured to minimize the loss of hydraulic fluid in the event of a leak in the working pipe, the use of a valve or shut-off device in the mobile work machine, and a method for minimizing the loss of hydraulic fluid in the mobile work machine in the event of a leak in the working pipe.

[0005] This problem is solved by a mobile work machine having the features of claim 1, the use of a valve or shut-off device in a mobile work machine having the features of claim 10, and a method for minimizing the loss of hydraulic fluid in a mobile work machine when a leak occurs in the operating piping, having the features of claim 11.

[0006] Accordingly, a mobile work machine is provided comprising a substructure, a superstructure, a boom assembly, and a hydraulic system, wherein the hydraulic system comprises a hydraulic pump, an operating pipe, a hydraulic load, a volume control valve configured to adjust the oil flow in the operating pipe connected to the hydraulic load to actuate the hydraulic load, and a bypass that can bypass the volume control valve, wherein a suction device having a supply or suction function is located in the bypass, and when overpressure is applied to the operating pipe, the bypass is closed, and when underpressure is applied to the operating pipe, the bypass is opened, and the operating pipe or the hydraulic load connected to the operating pipe is provided capable of supplying or suctioning hydraulic fluid through a supply pipe. The suction device has an emergency stop function, or the hydraulic system includes an emergency stop device, and the emergency stop function and the emergency stop device are configured to close the pipe or supply pipe in the bypass when a leak is detected in the operating pipe. "Supplying" means that hydraulic fluid flows through the supply pipe, which is done, for example, by suction or back pressure. The boom assembly may comprise two or more members, specifically one boom. Preferably, the boom assembly comprises one boom and one arm, the arm capable of supporting a (hydraulic) attachment.

[0007] An emergency stop function or device can prevent hydraulic fluid from being supplied to disabled (shut off) hydraulic lines, thus avoiding hydraulic fluid leakage. This is true even if the hydraulic pump of the work machine continues to operate. This prevents damage to the hydraulic pump due to dry running. Furthermore, this method is also beneficial for operational maintenance and allows for the saving of hydraulic fluid (resource conservation). All other functions of mobile work machines, especially excavators, remain available. It is not necessary to completely stop the work machine. This offers significant advantages.

[0008] An emergency that could lead to shutoff or emergency stop is a leak from the aforementioned operating piping, and is particularly effective if it is a rupture of at least one flexible manifold, in the immediate vicinity of a tool attached to the boom assembly or in the immediate vicinity of a hydraulic working cylinder of the boom assembly.

[0009] Preferably, the hydraulic load is a hydraulic cylinder that moves the boom assembly and / or hydraulic attachment. The hydraulic cylinder may be, for example, an arm cylinder, a bucket cylinder, a boom cylinder, an intermediate boom cylinder, or a hydraulic unit of an attachment. In particular, a hydraulic unit of an attachment is a hydraulic tool, such as a digging tool, demolition shears, a forestry tool, or a civil engineering tool. With these tools and their usual use, the risk of piping damage due to damage during operation is particularly high. In this regard, the emergency stop function described is particularly advantageous when the frame is self-propelled.

[0010] The hydraulic cylinder may be single-acting or double-acting. The volume control valve may be a 4 / 3 proportional valve. It is preferable that four connection points are provided. In the case of a double-acting hydraulic cylinder, the first connection point is connected to the first operating pipe connected to the first chamber of the hydraulic cylinder. The second connection point is connected to the second operating pipe connected to the second chamber of the hydraulic cylinder. The third connection point is connected to the pressure pipe extending from the hydraulic pump, and the fourth connection point is connected to the tank piping to the tank. A (primary) pressure limiting valve may be provided between the tank piping and the pressure piping.

[0011] This is advantageous when, in the bypass, a pressure limiting valve is positioned parallel to the suction device, or when the suction device has a (secondary) pressure limiting function.

[0012] In one effective embodiment, the bypass includes a branch point from the tank piping, and the supply pipe is the tank piping. Thus, hydraulic fluid can flow from the tank to the working piping via the bypass.

[0013] The effective location of the emergency stop device is in the bypass between the branching point from the operating piping (where the suction device is located) and the branching point connected to the piping where the pressure limiting valve is located. The pressure limiting valve remains active even when the bypass is shut off in the event of a leak, protecting the mobile work machine from damage. The location between the branching point connected to the piping where the suction device and the pressure limiting valve are located is particularly preferred.

[0014] Preferably, the emergency stop device, or the suction device having an emergency stop function, is configured to alternately switch between a shut-off state and an open state.

[0015] A suction device with an emergency stop function may include a check valve that can be closed manually, electrically, hydraulically, and / or pneumatically.

[0016] Preferably, the control unit operates a volume control valve, and the control unit is also connected to an emergency stop device and / or suction device, which activates the emergency stop device and / or suction device to close the piping when a leak is detected in the operating piping.

[0017] The hydraulic system may be configured to include pressure sensors and / or hydraulic circuits for detecting leaks in the working piping. Leaks may also be detected by, or only by, the user of the mobile work machine, and a signal may be sent to the control unit by activating an emergency stop device (emergency stop switch / operating unit). Preferably, the emergency stop device is located in the operator's cab of the mobile hydraulic machine. If a leak is detected, the operator of the mobile hydraulic (construction) machine can activate the emergency stop device to prevent further leakage of hydraulic fluid at the point of damage.

[0018] In one preferred embodiment, the mobile work machine is a hydraulic construction machine, specifically a long-arm boom excavator having a reach height in the range of 15m to 90m and specifically in the weight class of 25t to 400t. However, it may also be a mini excavator up to about 10t or a small excavator up to about 18t.

[0019] Furthermore, the use of valves or shut-off devices in mobile work machines is provided. Mobile work machines are, - Substructure and, - Superstructure and, - Boom assembly and, - A hydraulic system comprising a hydraulic pump, an operating pipe, a hydraulic load, a volume control valve configured to adjust the oil flow in the operating pipe connected to the load in order to operate the hydraulic load, and a bypass that can bypass the volume control valve, wherein a suction device having a supply function is arranged in the bypass, and when overpressure is applied to the operating pipe, the bypass is closed, and when low pressure is applied to the operating pipe, the bypass is opened, allowing the operating pipe or the hydraulic load connected to the operating pipe to draw in or be supplied with hydraulic fluid via a supply pipe. If a leak is detected in the operating piping, the bypass piping or supply pipe is shut off, thereby blocking the volumetric flow rate of the hydraulic fluid in the direction of the operating piping.

[0020] The hydraulic system can be configured as described above.

[0021] Furthermore, a method is provided for minimizing hydraulic fluid loss in the event of a leak in the operating piping of the aforementioned mobile work machine. This method is: If a leak occurs in the operating piping, a. Moving at least one capacity control valve to the shut-off position and / or holding it in the shut-off position, thereby shutting off the operating piping from the pressure piping connected to the hydraulic pump, b. shutting off the bypass or supply pipe, thereby avoiding the hydraulic oil from flowing into the working pipe through the bypass;

[0022] Steps a and b can be executed substantially simultaneously or continuously in time. This method has particularly high reliability by operating easily in an emergency. The mobile working machine can be configured as described above.

[0023] Preferably, this method c. After solving the leakage, further comprising the step of releasing the shut-off of the volume control valve, opening the bypass or supply pipe, and enabling the hydraulic oil to flow into the working pipe through the bypass when the inside of the working pipe is at a low pressure.

[0024] This has the advantage that it can be restored to the original non-leaking state without using tools and / or without, for example, requiring the replacement of cartridges. The emergency stop function can be released again, for example, by newly operating the emergency switch after solving the leakage. Also, the valve and the shut-off device can be configured to be automatically operated by a sensor that detects a pressure drop, or the valve and the shut-off device can be completely automatically hydraulically closed when the pressure drops.

[0025] Preferably, after steps a and b are executed, the method - shutting off a second bypass through which the volume control valve can be bypassed, wherein a suction device having a supply function is arranged in the second bypass, and when an overpressure is applied to a second working pipe associated with a hydraulic load, the second bypass is closed, and when a low pressure is applied to the second working pipe, the second bypass is opened, enabling the second working pipe or the hydraulic load connected to the second working pipe to suck hydraulic oil through the supply pipe; - shutting off the supply pipe, which is performed to avoid the leakage of hydraulic oil from the first working pipe even when there is no leakage in the second working pipe.

[0026] It is also conceivable to block the supply pipe so that neither of the two bypasses can supply, suck, or replenish. In this case, the capacity control valve preferentially takes a state in which both operating pipes are deactivated and the pressure pipe is connected to the tank pipe. The hydraulic cylinder is preferably double-acting, and each operating pipe is connected to each chamber.

[0027] Also, it is conceivable to design a suction device having an emergency stop device and / or an emergency stop function such that two components associated with a single hydraulic load are hydraulically and / or electrically interconnected so that both bypasses can be extremely easily blocked in case of leakage.

[0028] Hereinafter, two preferred embodiments of the present invention will be described in more detail with reference to the drawings. In the drawings, the same or functionally identical components are denoted by the same reference numerals.

Brief Description of the Drawings

[0029] [Figure 1] It is a simplified schematic diagram showing an embodiment of a hydraulic system of a mobile working machine equipped with a hydraulic cylinder. [Figure 2] It is a further simplified schematic diagram showing an embodiment of a hydraulic system of a mobile working machine equipped with an additional emergency stop device. [Figure 3] It is a diagram showing an excavator.

Modes for Carrying Out the Invention

[0030] Figures 1 and 2 show the hydraulic control circuit 1 of a mobile work machine. A pump 3 driven by a motor 2 sends hydraulic fluid into a pressure pipe 4 to actuate a double-acting hydraulic cylinder 5. The control unit 6 of the hydraulic control circuit is shown in a simplified form. A volume control valve 7 is provided to actuate the hydraulic cylinder 5 hydraulically. The volume control valve 7 is configured as a 3 / 4-way valve, specifically a 3 / 4-way proportional valve, as shown in the figure. It has four connections A, B, P, and T. The first connection A is connected to the first operating pipe 8, which is connected to the first chamber 9 of the hydraulic cylinder 5. The second connection B is connected to the second operating pipe 10, which is connected to the second chamber 11 of the hydraulic cylinder 5. The third connection P is connected to the pressure pipe 4, and the fourth connection T is connected to the tank pipe 12 (also called the return pipe), which is connected to the tank 13.

[0031] In the first extreme state of the volume control valve 7, the first connector A is connected to connector P and pressure piping 4, while the second connector B is connected to the fourth connector T. In this case, the hydraulic fluid can flow from pressure piping 4 into the first chamber 9 of the hydraulic cylinder 5, while the second chamber 11 is connected to the tank 13 via connectors B and T. This causes the piston 14 of the hydraulic cylinder 5 to move in the first direction. In the neutral position (second extreme state) of the volume control valve 7 shown in the diagram, connectors A and B are deactivated, i.e., closed, and pressure piping 4 is connected to tank piping 12. The piston 14 of the hydraulic cylinder 5 remains in its current position because there is no inflow or outflow. This is a shut-off state. In the third extreme state of the volume control valve 7, connector P is connected to connector B, and connector A is connected to connector T. In this case, the hydraulic fluid flows from the pressure pipe 4 into the second chamber 11 of the cylinder 5, and the first chamber 9 is connected to the tank 13 via connections A and T. The hydraulic fluid then applies force to the piston 14 of the hydraulic cylinder 5, moving the piston 14 in a second direction opposite to the first direction. As described above, the volume control valve 7 is configured as a proportional valve. The hydraulic fluid flow coming from the pressure pipe 4 is distributed to chambers 9 and 11 by changing the valve state between three extreme states. As a result, it is possible to produce a predetermined speed of piston movement by controlling / adjusting the volume flow rate.

[0032] A branching point 15 is provided in the pressure piping 4 downstream of the outlet of pump 3 and upstream of the volume control valve 7, from which piping 16 branches off. Piping 16 is connected to tank 13 via a pressure limiting valve 17 that opens in the direction of tank 13.

[0033] The tank piping 12 is connected to the tank via a return flow filter 18. It is conceivable that a different filter, for example, using a different filter medium, may be used instead of the illustrated return flow filter. The return flow filter 18 can be bypassed by a bypass 19 equipped with a differential pressure valve 19 that opens toward the tank 13. Here, the return flow filter overriding pressure is in the range of 0.5 to 1.5 bar. Between the return flow filter 18 and the branching point to the pressure limiting valve 17, an optional spring-loaded check valve, shown here, is provided, which opens toward the tank 13 and generates a back pressure in the range of 3 to 8 bar, preferably about 5 bar.

[0034] The volume control valve 7 includes two bypasses 20 and 21. The first bypass 20 starts from the tank piping 12 between connection T and the branching point to the pressure limiting valve 17 and ends at the branching point 22 of the first operating piping 8. A check valve 23 is located in the first bypass 20. A secondary pressure limiting valve 24 is provided in the bypass 20 in parallel with the check valve 23. The secondary pressure limiting valve 24 is located in the piping that branches off from the first operating piping 8 between connection A and the branching point 22 of the first bypass 20, and this piping ends at the branching point 25 between the check valve 23 in the first bypass 20 and the branching point of the tank piping. The check valve 23 functions as a so-called supply valve or suction valve connected to the tank 13. When overpressure is applied to the first operating piping 8, the check valve 23 closes. However, when the first operating pipe 8 is under low pressure (relative to the back pressure of the spring-pressurized check valve or counterbalance valve in the illustrated embodiment), the suction valve opens, allowing the first operating pipe 8 or the first chamber 9 to be supplied from the tank piping 12 or tank 13, thus avoiding cavitation. Even when sufficient volumetric flow rate is not available to supply the hydraulic cylinder, the suction valve allows for problem-free operation.

[0035] The second bypass 21 of the capacity control valve is configured similarly to the first bypass 20 and protects the second operating piping 10 or the second chamber 11 from overload and cavitation. The bypass piping 26 of the second bypass 21 is connected to the tank piping 12 at a branch point 27 located on the tank side, between the branch point to the pressure limiting valve 17 and the branch point to the first bypass.

[0036] Furthermore, the suction valve may generally be connected to the return piping of an open hydraulic circuit (for example, piping that returns directly to the tank). The suction valve and the secondary pressure limiting valve can be combined into a single cartridge. By integrating the pressure limiting function and the supply function into a single valve, miniaturization is possible.

[0037] An operating unit 28, configured as a joystick, can be connected to a control unit 29 to control the volume control valve 7. The latter is connected to the volume control valve 7 via signal lines 30 and 31.

[0038] The two operating pipes 8 and 10 can be formed in the form of channels, pressure medium pipes, or flexible hoses. Flexible hoses are essential for movable hydraulic cylinders. As explained in detail above, if a flexible hose gets caught on a protruding rebar and breaks during operation, for example during building demolition, a conventional hydraulic system would experience a large amount of hydraulic fluid leakage from the point of damage.

[0039] If the return oil passes through the return flow filter 18 due to the return flow filter overcoming pressure before reaching the tank 13, the filter back pressure always acts on the suction valve 23, opening this valve when a leak occurs in the associated operating piping, and the oil is then immediately pushed out (by the aforementioned filter back pressure). If an optional spring-pressurized check valve (generally a counterbalance valve) is also provided, the oil leak from the aforementioned fault point in the operating piping will be further exacerbated. In this case, when a leak occurs, there is no suction from the tank via the suction valve, and pre-pressurization is generated in the bypass circuit (suction circuit) by, for example, a small standby transport rate (3-10 liters / min) of a control pump or constant-speed pump that is running but not adjusted to high output by a control command, causing oil to leak out. When a non-faulty hydraulic circuit is operating, the pump is adjusted to high output up to the maximum discharge rate depending on the operating intensity. From the aforementioned fault point in the operating piping, the return oil flows out from the functional part that was activated when the suction valve opened, rather than through the existing path where it returns to the tank via the return flow filter through the counterbalance valve.

[0040] To prevent this, the present invention provides an emergency stop device or emergency stop function. The emergency stop device or emergency stop function prevents hydraulic fluid from flowing to the damaged area in the operating piping in the event of an emergency, and also prevents hydraulic fluid from reaching the damaged area via a bypass that bypasses the volume control valve and leaking out of the leak in the operating piping.

[0041] Figure 1 shows a first embodiment of the emergency stop device. In all cases, the check valve 23 is configured as a controllable valve. Here, the check valve 23 must be configured to switch from the open position to the closed position regardless of whether there is opening pressure when the hose is damaged. This closing member can be moved to the closed position by hydraulic, mechanical, electrical, or pneumatic means.

[0042] If the supply function is not achieved by the check valve, the present invention is configured such that, in the event of damage, a valve or valve device that provides the supply function is controlled, operated, or moved accordingly to prevent the flow of hydraulic fluid through a bypass to the damaged operating pipe.

[0043] Furthermore, in such an emergency, it is necessary to ensure that the damaged operating pipe between the damaged area and the pressure pipe 4 is shut off or blocked. This means that the user of the mobile work machine does not operate the operating unit 28 for controlling the hydraulic cylinder. The user may be instructed to do so. To ensure that the shutoff of the damaged operating pipe is maintained even if the operating unit is operated, the control unit may be instructed not to transmit the fact that the operating unit has been operated to the capacity control valve. Alternatively, the operating unit may be locked, for example. It is also conceivable that the control or state change of the capacity control valve may be prevented in other ways. It is also conceivable that in an emergency, the capacity control valve may automatically transition to a state where the damaged operating pipe is blocked. Furthermore, it is conceivable that the operating pipe may be closed using an additional valve or valve device or shutoff device that is controlled, operated, or moved in response to the emergency.

[0044] Figure 2 shows a second embodiment of the emergency stop device 32 with two different mounting positions. Only one of these mounting positions is used. In the first mounting position, the emergency stop device 32 is located in the bypasses 20, 21 between the branch point 25 to the secondary pressure limiting valve 24 and the check valve 23. In an emergency, the emergency stop device 32 blocks the flow of hydraulic fluid through the tank piping 12 to the damaged working pipe. The emergency stop device 32 may be an additional valve, valve gear, or shutoff device as understood applicable. Examples of shutoff devices include slide valves, ball valves, etc. A 2 / 2-way valve, held in the open position by a spring in the neutral (stationary) position, is shown as the emergency stop device 32. This is an electrically or electronically controlled solenoid valve, controllable by the control unit 29. In an emergency, the control unit can move the 2 / 2-way valve to the closed position, shutting off the bypasses 20, 21 connected to the tank piping 12 and avoiding the supply. This position ensures that the pressure limiting function remains active even if the piping is shut off by the emergency stop device 32.

[0045] In the second mounting position, the emergency stop device 32 is located in the bypasses 20 and 21 between the branch point from the tank piping 12 and the branch point 25 to the secondary pressure limiting valve 24. When the supply function and pressure limiting function are implemented together in a common device, the emergency stop device can be installed on one side or the other side of the bypass of that device. Generally, it is conceivable that the emergency stop device may be installed somewhere in the bypass, regardless of how the supply function and pressure limiting function are technically implemented. It is also conceivable that the emergency stop device may be installed outside the bypass, i.e., in the tank piping, between the branch point to the bypass and the return flow filter, specifically between the branch point to the bypass and the branch point to the pressure limiting valve. This is because the pressure limiting function remains active. When the emergency stop device is installed between the branch point to the bypass near the filter and the branch point to the pressure limiting valve, the emergency stop device can shut off the supply to both suction valves and the flow of hydraulic fluid to both bypasses. This embodiment may be particularly low-cost. In this case, it is preferable that both bypass pipes have a single (common) connection to the tank piping, the connection between the volume control valve and the tank piping is located between the emergency stop device and the filter, and the piping from the volume control valve to the tank has a branch point to the pressure limiting valve. The joint of the two bypass pipes is located on the side of the connection between the volume control valve and the tank piping away from the filter. This ensures that the emergency stop device shuts off only the control unit affected by the leak, while other functions and control units remain available.

[0046] The first bypass, the second bypass, and the associated emergency stop devices are preferably configured identically. If each bypass is provided with one emergency stop function, they can be configured identically. However, due to space limitations or other structural constraints, it is conceivable that the emergency stop devices, or the check valves having emergency stop functions, may be configured differently.

[0047] Generally, it is conceivable to use an emergency stop device or a check valve with an emergency stop function that automatically closes if a leak occurs in the operating piping and the pressure drops as a result. It is also conceivable to use a sensor that detects such a pressure drop and notifies the control unit. The control unit then determines whether an emergency has occurred or whether appropriate action needs to be taken. It may also be effective for the user of the mobile work machine to, for example, use an emergency stop button to identify the damaged area and transmit that information to the control unit, which then takes appropriate action.

[0048] Furthermore, in the event of an emergency, it may be beneficial if, when an emergency stop device or check valve with an emergency stop function closes the bypass piping on one bypass, the same action is automatically performed on the other bypass of the same hydraulic cylinder.

[0049] It is particularly preferable that the emergency stop device, or a check valve with an emergency stop function, can be returned to a neutral state without requiring significant effort. This allows, for example, the shut-off device to reopen the piping, or the valve or valve mechanism to return to a neutral position, thus eliminating the need to replace parts.

[0050] Figure 3 shows a mobile work machine 33 in a preferred embodiment, specifically as a long-arm boom excavator, with a substructure 34. The substructure 34 is connected to the superstructure 36 via a slewing device 35 that is rotatable around a pivot axis S. The slewing device 35 enables controlled slewing motion between the superstructure 36 and the substructure 34 about the pivot axis S. Generally, excavators can be distinguished into mobile excavators and crawler excavators. The substructure 34 can be equipped with tires on the vehicle body, in which case it is called a mobile excavator, and mobile excavators are used only in the weight class up to 25 tons (t). On the other hand, the substructure 34 can be equipped with chains, in which case it is called a crawler excavator, and is used in all weight classes. Mobile and crawler excavators are distinguished as self-propelled land vehicles from other types of excavators, such as amphibious excavators. In a preferred embodiment, the long-arm boom excavator is realized as a crawler excavator belonging to the weight class of 25 tons (t) to 400 tons (t), typical for demolition work. The superstructure 36 has a cab 37 at its front end in its direction of travel F (straight direction), and a counterweight 38 is positioned opposite the cab 37. Figure 3 shows a three-stage boom assembly 39 fixed to the superstructure 36 either to the side or behind the cab 37. The boom assembly 39 comprises three continuous members 40, 41, and 42. The first member 40 is called the boom, the second member 41 is called the intermediate boom, and the third member, which is furthest from the superstructure, is called the arm 42. Here, two continuous members are bolted together so as to be swivelable relative to each other. The boom assembly 39 further includes a boom cylinder 43 that can move the first member 40 and an intermediate boom cylinder 44 that can move the second member 41 of the boom assembly 39. Furthermore, a driveable arm cylinder 45 is provided to move the arm 42. An attachment 47 is fixed to the free end of the arm 42 through which an arm head bolt 46 passes. This connection can be advantageously made by a quick hitch.The attachment 47 and the quick hitch are also swivelable around a pivot axis defined by the arm head bolt 46. In this embodiment, the attachment 47 is a gripping tool, but any hydraulic attachment, such as scissors, can be used.

[0051] The mobile hydraulic construction machine is equipped with a hydraulic system that uses hydraulic fluid to drive, in particular, the hydraulic cylinders of the boom cylinder 43, intermediate boom cylinder 44, arm cylinder 45, and optionally the auxiliary equipment 42. The hydraulic system includes at least one valve block 48, a hydraulic fluid tank 49, and a hydraulic pump 50, all located within the superstructure 36 (also called the upper carriage). The hydraulic pump 50 delivers the hydraulic fluid to the hydraulic system and is connected to at least one valve block 48 by hydraulic connections. Multiple pumps can be used in a single hydraulic system if the capacity of a single pump is insufficient for the required application or if redundancy is needed in the system. At least one valve block 48 controls and regulates the flow of hydraulic fluid to the hydraulic cylinders described above. From at least one valve block 48, operating pipes 51 lead to the hydraulic cylinders.

[0052] In Figure 3, the hydraulic system is shown in its simplest and most schematic form. For example, only one operating pipe 51 is shown, but depending on the type of attachment and construction machine used, there may be at least two hydraulic pipes 51 per hydraulic cylinder. The number of hydraulic pipes (used or connected) is determined by the type of attachment 47 and the movements it can perform. Thus, an attachment may have hydraulic cylinders to perform operations such as opening and closing, or it may have hydraulic cylinders, such as bucket cylinders, to move the attachment relative to the arm. Hydraulic cylinders may be single-acting or double-acting.

[0053] The hydraulic piping is formed by channels fixed to the top of the boom assembly or by flexible hose piping, depending on its location and destination. In areas where movement is required, the hose piping is arranged in a curved shape. These areas are called flexible manifolds 52 and differ from fixed, rigid manifolds that can be purchased as separate parts. The flexible manifolds 52 allow the individual members of the boom assembly 39 to pivot relative to each other without the hydraulic piping 51 being cut or damaged.

[0054] The emergency stop device or control unit equipped with the emergency stop function described above can be incorporated into the hydraulic system of the mobile work machine described above. In this case, the emergency stop device can be used on, for example, one work cylinder, multiple work cylinders, or all work cylinders of an attachment, arm, boom, etc., to prevent a large amount of hydraulic fluid from leaking out in the event of a hose failure. This makes it particularly easy and reliable to avoid damage caused by a large amount of hydraulic fluid leaking out when a leak occurs in the hydraulic piping. In addition, since the other functions of the mobile work machine are maintained, it is possible to move the work machine, for example, to repair a leak. This is a particularly significant advantage when the leak is located away from the superstructure, for example in the boom assembly area, specifically in the arm or bucket, and the user cannot reach that location when the leak occurs.

Claims

1. A mobile work machine (33) comprising a lower structure (34), a superstructure (36), a boom assembly (39), and a hydraulic system, wherein the hydraulic system comprises a hydraulic pump (3), operating pipes (8, 10), a hydraulic load (5), a volume control valve (7) configured to adjust the oil flow in the operating pipes (8, 10) connected to the hydraulic load (5) in order to operate the hydraulic load (5), and bypasses (20, 21) that can bypass the volume control valve (7), wherein a suction device (23) having a supply function is arranged in the bypasses (20, 21), and when overpressure is applied to the operating pipe (8), the bypass (20) is closed, and when low pressure is applied to the operating pipe (8), the bypass (20) is opened, allowing hydraulic fluid to be supplied to the operating pipe (8) or the hydraulic load (5) connected to the operating pipe (8) via a supply pipe (12), A mobile work machine (33) characterized in that the suction device (23) has an emergency stop function, or the hydraulic system includes an emergency stop device (32), and the emergency stop function and the emergency stop device (32) are configured to close the piping in the bypass (20) or the supply pipe (12) when a leak is detected in the operating piping (8).

2. The mobile work machine according to claim 1, characterized in that the hydraulic load (5) is a hydraulic cylinder for moving the boom assembly (39) and / or the hydraulic attachment (47).

3. The mobile work machine according to claim 1 or 2, characterized in that a pressure limiting valve (24) is arranged in parallel with the suction device (23) in the bypass (20), or the suction device has a pressure limiting function.

4. The mobile work machine according to any one of the preceding claims, characterized in that the bypass (20) is provided with a branching point from the tank piping, and the supply pipe (12) is the tank piping.

5. The mobile work machine according to claim 3 or 4, characterized in that an emergency stop device (32) is provided in the bypass (20, 21) between a branching point (22) from the operating pipe (8) and a branching point (25) connected to the pipe in which the pressure limiting valve (24) is located.

6. The mobile work machine according to any one of the preceding claims, characterized in that the emergency stop device (32), or the suction device (23) having an emergency stop function, is configured to alternately switch between a shut-off state and an open state.

7. The mobile work machine according to any one of the preceding claims, characterized in that the suction device (23) having an emergency stop function includes a check valve that can be closed manually, electrically, hydraulically, and / or pneumatically.

8. A mobile work machine according to any one of the preceding claims, characterized in that a control unit (29) operates the volume control valve (7), and the control unit (29) is also connected to the emergency stop device (32) and / or the suction device (23), and when a leak is detected in the operating pipe (8), the emergency stop device (32) and / or the suction device (23) are operated to close the pipe.

9. The mobile work machine according to any one of the prior claims, characterized in that the hydraulic system includes a pressure sensor and / or a hydraulic circuit for detecting leaks in the operating pipe (8).

10. The use of valves or shut-off devices in a mobile work machine (33), The aforementioned mobile work machine (33) is - Substructure (34) and, - Superstructure (36) and, - Boom assembly (39), - A hydraulic system comprising a hydraulic pump (3), operating pipes (8, 10), a hydraulic load (5), a volume control valve (7) configured to adjust the oil flow in the operating pipes (8, 10) connected to the load (5) in order to operate the hydraulic load (5), and a bypass (20) that can bypass the volume control valve (7), wherein a suction device (23) having a supply function is arranged in the bypass (20), and when overpressure is applied to the operating pipe (8), the bypass (20) is closed, and when low pressure is applied to the operating pipe (8), the bypass (20) is opened, allowing the operating pipe (8) or the hydraulic load (5) connected to the operating pipe (8) to draw hydraulic fluid through a supply pipe (12). In the event that a leak is detected in the operating pipe (8), the bypass pipe (20) or the supply pipe (12) is shut off, thereby blocking the volumetric flow rate of the hydraulic fluid in the direction of the operating pipe (8).

11. A method for minimizing hydraulic fluid loss in a mobile work machine (33) when a leak occurs in the operating pipe (8) described in any one of the preceding claims 1 to 9, If a leak occurs in the aforementioned operating pipe (8), a. The steps of moving at least one capacity control valve (7) to the shut-off position and / or holding it in the shut-off position, thereby shutting off the operating pipe (8) from the pressure pipe (4) connected to the hydraulic pump (3), b. A method comprising the step of shutting off the bypass (20) or the supply pipe (12) thereby preventing the hydraulic fluid from flowing into the operating pipe (8) via the bypass (20).

12. c. The method according to claim 11, further comprising the step of releasing the shutoff of the volume control valve (7) after resolving the leak, opening the bypass (20) or the supply pipe (12), and allowing hydraulic fluid to flow into the operating pipe (8) via the bypass (20) when the pressure inside the operating pipe (8) is low.

13. After steps a. and b. have been performed, - A step of shutting off a second bypass (21) that can bypass the volume control valve (7), wherein a suction device having a supply function is arranged in the second bypass (21), and when an overpressure is applied to the second operating pipe (10) associated with the hydraulic load (5), the second bypass (21) is closed, and when a low pressure is applied to the second operating pipe (10), the second bypass (21) is opened, allowing the second operating pipe (10) or the hydraulic load (5) connected to the second operating pipe (10) to draw hydraulic fluid through the supply pipe (12), The method according to claim 11 or 12, further comprising the step of shutting off the supply pipe (12), the shutting off being done to prevent hydraulic fluid from leaking from the first operating pipe (8) even if there is no leak in the second operating pipe (10).

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