JP2011226104A - Descent device and descent method of long front at time of power abnormal stop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a descent device and a descent method, at the time of the power abnormal stop, of the long front allowed be in stoppage posture in which the front is lowered in the case of a power abnormal stop in the work machine having a long front.SOLUTION: In the descent device of the long front, a pilot-hydraulic-pressure pipeline 58 for emergencies is formed so as to be branched from pilot-valves 46 to 49 and a valve 52 provided in a discharge pipeline 53 of a pilot pump 23 and preventing the back run of the pilot pressure oil to the pilot pump 23. The descent device includes a coupler 61 which removably connects the pilot-hydraulic-pressure pipeline 58 for emergencies to a discharge pipeline 53A of a pilot pump 23A of an accompanying work machine 56. Pilot pressure oil is supplied to the work machine through the pilot-hydraulic-pressure pipeline for emergencies from the accompanying work machine and a control valve is switched to the arm descent direction. And hydraulic oil is circulated between a bottom room of an oil hydraulic cylinder for an arm drive and a rod chamber, so that the arm is lowered.

Description

  In the working machine such as a dismantling machine or a cement injection machine having a long front composed of a plurality of arms as an articulated front for working at a high place, a problem occurs in an engine and a hydraulic pump of a hydraulic power unit. In addition, the present invention relates to a device and a descending method for lowering a long front to make a resting posture for safety in the case of abnormal power stop such as engine stop due to running out of fuel.

  When performing dismantling work at high places such as a building or concrete injection, a working machine having an articulated front formed by connecting a plurality of long arms is used (see, for example, Patent Document 1).

JP 2008-272648 A

  In such a work machine having a long front, when the power or the engine of the hydraulic power unit fails or the engine stops due to running out of fuel, the front is lowered for safety and landing. It is preferable to have a resting posture. However, the conventional work machine has a problem that it does not have a means for lowering the front at the time of abnormal power stop, and has to leave the front standing until the power source recovers. .

  In view of the above-described problems, the present invention provides a working machine having a long front, and a descent device for abnormal power stop at a long front which can be in a resting posture in which the front is lowered at the time of abnormal power stop. And to provide a descent method.

The long front power lowering descent device according to claim 1 is:
A multi-jointed long front mounted on the upper swing body of the work implement, connected to a plurality of arms by a hydraulic cylinder so as to be rotatable, and a work tool attached to the tip arm;
A control valve for operating the hydraulic cylinder, a pilot valve for operating the control valve, and a pilot pump for supplying pilot pressure oil to the control valve via the pilot valve;
A relief valve provided between a hydraulic line between the control valve and the hydraulic cylinder and an oil tank, and a reverse valve provided in parallel with the relief valve for preventing excessive hydraulic pressure in the hydraulic line. In the descent device at the time of abnormal power stop of the long front in a work machine equipped with a stop valve,
A check valve provided between the pilot pump and the pilot valve to prevent backflow of pilot pressure oil to the pilot pump;
An emergency pilot hydraulic line provided by branching from between the check valve and the pilot valve to prevent backflow of pilot pressure oil to the pilot pump;
And a coupler provided in the emergency pilot hydraulic line so as to be able to take in the pilot pressure oil from the outside.

The lowering method for abnormal power stop of the long front according to claim 2 is:
A multi-jointed long front mounted on the upper swing body of the work implement, connected to a plurality of arms by a hydraulic cylinder so as to be rotatable, and a work tool attached to the tip arm;
A control valve for operating the hydraulic cylinder, a pilot valve for operating the control valve, and a pilot pump for supplying pilot pressure oil to the control valve via the pilot valve;
A relief valve provided between a hydraulic line between the control valve and the hydraulic cylinder and an oil tank, and a reverse valve provided in parallel with the relief valve for preventing excessive hydraulic pressure in the hydraulic line. In the descent method at the time of abnormal power stop of the long front in a work machine equipped with a stop valve,
A check valve provided between the pilot pump and the pilot valve, which prevents a backflow of pilot pressure oil to the pilot pump; and the check valve and the pilot which prevents a backflow of pilot pressure oil to the pilot pump There is provided an emergency pilot hydraulic line branched from the valve and a coupler provided in the emergency pilot hydraulic line so that pilot pressure oil can be taken from the outside. With
The companion work machine of the work machine is also provided with an emergency pilot hydraulic line and a coupler branched from the check valve and the pilot valve to prevent the backflow of the pilot pressure oil to its own pilot pump. Leave
When the power of the work machine is stopped, the emergency pilot hydraulic line of the work machine is connected to the emergency pilot hydraulic line of the work machine, and the emergency pilot hydraulic line of the companion work machine is set to these emergency pilot hydraulic lines, respectively. Connect directly through the provided coupler, or indirectly through a relay emergency pilot hydraulic line and coupler,
By operating the pilot pump of the companion work machine, the pilot pressure oil from the pilot pump of the companion work machine passes through the emergency pilot hydraulic pipelines of the companion work machine and the work machine, and the work during the power stop The control valve is supplied to the pilot valve of the machine and can be switched by the operation of the pilot valve of the work machine that is stopped.
It is generated in the oil chamber of the hydraulic cylinder corresponding to the arm by operating the pilot valve of the work implement that has been stopped corresponding to the arm from the upper arm and switching the corresponding control valve. Hydraulic oil is circulated between the bottom chamber and the rod chamber of the hydraulic cylinder, and the corresponding hydraulic cylinder is sequentially operated from the upper arm in the arm lowering direction to lower the long front. Features.

  According to the first aspect of the present invention, an emergency pilot hydraulic line is provided in the discharge line of the pilot pump and is branched from the check valve and the pilot valve provided in the discharge line of the pilot pump. And a coupler for detachably connecting this emergency pilot hydraulic line to the discharge line of the pilot pump of another work machine, so that the pilot line of the work machine where power is stopped and the other work machine Are connected by an emergency pilot hydraulic line, the corresponding control valve can be switched by operating the pilot valve corresponding to the arm.

  When the arm-corresponding control valve is switched in the arm lowering direction, the reverse of the parallel arrangement of the control valve and the relief valve between the hydraulic cylinder and the oil tank due to the hydraulic pressure in the hydraulic chamber of the hydraulic cylinder generated by the weight of the arm. The hydraulic oil circulates through the stop valve, and the arm for pilot valve operation descends. By sequentially performing such lowering of the arm from the upper arm, the long front can be in a safe resting position even in a stopped state due to power failure.

  According to the second aspect of the present invention, the work machine whose power is stopped and the pilot pipes of the companion work machine are connected by the emergency pilot hydraulic pipe, and the companion work is passed through the emergency pilot hydraulic pipe. The pilot pressure oil from the pilot pump of the machine is supplied to the pilot valve of the power stop working machine, and the corresponding control valve is switched by the operation in the arm lowering direction of the pilot valve corresponding to the upper arm. The hydraulic oil is circulated between the hydraulic cylinder and the oil tank through the control valve and the check valve by the hydraulic pressure generated in the oil chamber of the hydraulic cylinder by its own weight, thereby operating the hydraulic cylinder in the arm lowering direction. Since the long front is lowered by operating from the upper arm to the lower arm, power failure Even in the stopped state can be a long front and a safe resting posture.

It is a side view which shows an example of the working machine which has the elongate front used as the object of this invention. 1 is a hydraulic circuit diagram showing an embodiment of a long front power lowering descent device according to the present invention. It is a side view which shows the connection state of the pilot pipe line with the companion work machine at the time of the power stop in the working machine of this Embodiment. FIG. 3 is a hydraulic circuit diagram showing details of a part of the hydraulic circuit diagram of FIG. 2. It is a hydraulic circuit diagram which shows other embodiment of the descent | fall apparatus at the time of the abnormal power stop of the long front by this invention.

  FIG. 1 is a side view showing an example of a work machine 55 as an object of the present invention, and shows a case where the work machine 55 is a dismantling machine. The work machine 55 has an upper swing body 3 installed on a lower traveling body 1 via a swing device 2, and a hydraulic power unit 4 and a cab 5 as a hydraulic power source device are installed on the upper swing body 3 and an upper swing. An articulated front 6 is attached to the body 3. The multi-joint front 6 has a first arm 8 attached to the upper swing body 3 by a hydraulic cylinder 7 so as to be able to be lifted and lowered, and is pivotable around a pin 10 by a hydraulic cylinder 9 at the tip of the first arm 8. A second arm 11 to be attached and a third arm 14 attached to the tip of the second arm 11 so as to be rotatable around a pin 13 by a hydraulic cylinder 12 are provided. As shown in the figure, these arms 8, 11 and 14 have a total length longer than that of a general boom or arm used in a hydraulic excavator or the like so that dismantling work can be performed at a high place, and third. The tip of the arm 14 is configured to be able to reach a higher place. There are also cases where an articulated front is configured by combining two or four or more arms.

  A crushing tool 15 having a bowl-shaped crushing claw 15 a that is opened and closed by a hydraulic cylinder (not shown) is attached to the tip of the third arm 14 so as to be rotatable about a pin 16. Reference numeral 17 denotes a hydraulic cylinder having one end attached to the back surface of the third arm 14 for rotating the crushing tool 15. The other end of the hydraulic cylinder 17 is pin-connected to a link 18 pivotally attached to the third arm 14 and a link 19 pivotally attached to the crushing tool 15.

  In some embodiments, the first arm 8 may be composed of a single long one. In the present embodiment, however, the base end split arm 8a attached to the upper swing body 3 by a hydraulic cylinder 7 so as to be able to be lifted and lowered, An example is shown that includes a split arm for extension 8b that is added by adjusting the number of extension according to the length, and a tip split arm 8c that is detachably attached to the foremost end of the split arm for extension 8b. One end of the hydraulic cylinder 9 for rotating the second arm 11 is connected to the tip split arm 8c.

  FIG. 2 is a hydraulic circuit diagram of the working machine. 2, 55 is a hydraulic circuit included in the working machine shown in FIG. 1, 22A and 22B are main hydraulic pumps constituting the hydraulic power unit 4, and 23 is also a pilot pump. These hydraulic pumps 22A, 22B, and 23 are driven by an engine (not shown). Reference numeral 24 denotes an oil tank. Reference numeral 25 denotes a control valve set including control valves such as hydraulic cylinders 7, 9, 12, and 17 constituting the multi-joint front 6. The control valve set 25 includes control valves 26A and 26B for the hydraulic cylinder 7, a control valve 27 for the hydraulic cylinder 9, a control valve 28A and 28B for the hydraulic cylinder 12, a control valve 29 for the hydraulic cylinder 17, and a lower traveling body. 1 includes control valves 30 and 31 of travel motors (not shown) provided on the left and right of 1 and a control valve 32 of a swing motor (not shown) of the swing device 2.

  Reference numerals 34 and 35 denote hydraulic lines that connect the rod chamber 7a and the bottom chamber 7b of the hydraulic cylinder 7 and the secondary ports of the control valves 26A and 26B, respectively. Reference numerals 36 and 37 denote hydraulic lines that connect the rod chamber 9 a and the bottom chamber 9 b of the hydraulic cylinder 9 and the secondary port of the control valve 27, respectively. Reference numerals 38 and 39 denote hydraulic lines that connect the rod chamber 12a and the bottom chamber 12b of the hydraulic cylinder 12 to the secondary ports of the control valves 28A and 28B, respectively. Reference numerals 40 and 41 denote hydraulic lines that connect the rod chamber 17 a and the bottom chamber 17 b of the hydraulic cylinder 17 and the secondary port of the control valve 29, respectively.

  43A and 43B are secondary hydraulic lines of the control valves 28A and 28B, that is, hydraulic lines 38 and 39 respectively connected to the rod chamber 12a and the bottom chamber 12b of the hydraulic cylinder 12, and a line 63A connected to the oil tank 24. , 63C, a relief valve device. These relief valve devices 43A and 43B prevent the hydraulic pressure in the hydraulic pipes 38 and 39 from becoming excessive when the hydraulic cylinder 12 reaches the stroke end. The circuit configuration will be described later. 43 is a relief valve device similar to these relief valve devices 43A, 43B, and is provided for the secondary hydraulic lines of the other control valves 26A, 26B, 27, 29. A holding valve 44 is provided on the bottom chamber 7b side of the hydraulic cylinder 7, and the configuration thereof will be described later.

  46, 47, 48 and 49 are hydraulically operated pilot valves for operating the hydraulic cylinders 7, 9, 12 and 17, respectively. Reference numeral 50 denotes a hydraulically operated pilot valve of the swing motor control valve 32.

  52 is provided in the discharge pipe 53 of the pilot pump 23 to prevent the backflow of pilot pressure oil to the pilot pump 23, and 54 is provided between the check valve 52 and the pilot valves 46 to 50. The gate lock valve 54 is a gate lock valve that cuts off the supply of pilot pressure oil from the pilot pump 23 to the pilot valves 46 to 50 during operation interruption to prevent erroneous operation.

  FIG. 3 shows the working machine 55 when there is a malfunction in the hydraulic power unit engine or the hydraulic pumps 22A, 22B, 23 of the working machine 55 which is the dismantling machine, or when the engine stops due to running out of fuel. This shows a state in which the pilot hydraulic line of the companion work machine 56 is connected to the pilot hydraulic line by an emergency pilot hydraulic line (hydraulic hose) 57 for relay. When the work machine 55 is a demolition machine that dismantles at a high place as in this embodiment, the companion work machine 56 can be a demolition machine for a foundation part of a building or a block generated by the demolition to a relatively large block. A crusher that crushes, a crusher that crushes the large block into smaller blocks, a sorter that sorts the crushed pieces by material, and a work that can perform leveling work, such as the hydraulic excavator shown in the illustration There are machines.

  As shown in FIG. 2, the pilot of the working machine 55 is connected to connect the pilot pipes of the working machine 55 and the companion working machine 56 via the relay emergency pilot hydraulic pipe 57 shown in FIG. Branching from the check valve 52 and the pilot valves 46 to 49 in the hydraulic line 53 (branching from between the check valve 52 and the gate lock valve 54 in the present embodiment), the emergency pilot hydraulic pipe A path 58 is provided, and a coupler 61 for connecting to the emergency pilot hydraulic line 58A of the companion work machine 56 is provided in the emergency pilot hydraulic line 58. Further, the companion work machine 56 also branches from between the check valve 52A provided in the discharge pipe 53A of the pilot pump 23A and the pilot valve assembly 62 (in this embodiment, the check valve 52A and the gate). Branching from between the lock valve 54A) and an emergency pilot hydraulic line 58A is provided. Further, a coupler 61A is provided for detachably connecting the emergency pilot hydraulic line 58A to the coupler 60A at one end of the relay emergency pilot hydraulic line 57. The pilot valve assembly 62 is provided to operate the companion work machine 56 such as traveling, turning, and front of the work machine.

  FIG. 4 is a hydraulic circuit diagram showing an example of the hydraulic circuit around the control valve by extracting the control valves 28A and 28B. 12 is a hydraulic cylinder for rotating the third arm 14 relative to the second arm 11 as described above, 28A and 28B are control valves thereof, 38 and 39 are secondary ports and hydraulic pressure of the control valves 28A and 28B. This is a hydraulic line between the rod chamber 12a and the bottom chamber 12b of the cylinder 12. 63A and 63B are hydraulic lines connecting the secondary ports of the control valves 28A and 28B and the oil tank 24, respectively. 43A and 43B are the relief valve devices shown in FIG. 2, and each of the relief valve devices 43A and 43B is a relief valve 64 provided between the hydraulic pipes 38 and 39 and the pipe 63A connected to the oil tank 24, respectively. , 65 and check valves 66, 67 provided in parallel to the relief valves 64, 65, respectively. These relief valves 64 and 65 prevent the hydraulic pressure in the hydraulic lines 38 and 39 from becoming excessive after the stroke end of the hydraulic cylinder 12 or the like.

  FIG. 5 shows a configuration of the holding valve 44 shown in FIG. The holding valve 44 prevents the front 6 from being lowered due to breakage of the hydraulic line 35. This holding valve 44 is provided in connection with a port 71 on the bottom chamber 7b side, which is an oil chamber on the side from which hydraulic oil flows when the first arm 8 descends and the hydraulic cylinder 7 contracts.

  Such a holding valve 44 includes a hydraulically operated switching valve 72, a pilot operated check valve 73 provided between the switching valve 72 and the port 71 of the bottom chamber 7b, the switching valve 72 and the pilot operated valve. A check valve 74 connected in parallel to the series connection circuit with the check valve 73 and a relief valve 75 for preventing the hydraulic pressure in the bottom chamber 7b from becoming excessive. Pilot pressure oil from the pilot valve 46 applied to the operation chambers of the control valves 28 A and 28 B when the hydraulic cylinder 7 is contracted is supplied to the operation chamber 72 a of the hydraulically operated switching valve 72 through the pilot line 76 and the port 77. Is done.

  In the holding valve 44, when the hydraulic cylinder 7 is extended, hydraulic oil is supplied to the bottom chamber 7b through the hydraulic line 35, the port 78, and the check valve 74 by switching the control valves 28A and 28B.

  When the hydraulic cylinder 7 is contracted, the control valves 28A and 28B are switched in the opposite direction, and simultaneously, pilot pressure oil from the pilot valve 46 is supplied to the operation chamber 72a through the pilot line 76 and the port 77. As a result, the hydraulic operation switching valve 72 is switched to the lower position (communication position). At this time, since the pilot pressure applied to the pilot operation check valve 73 becomes the tank pressure, the pilot operation check valve 73 communicates also in the reverse direction. For this reason, the hydraulic oil in the bottom chamber 7b flows out through the pilot operation check valve 73 and the hydraulic operation switching valve 72 to the oil tank 24 through the hydraulic line 35 and the control valves 28A and 28B.

  In the holding valve 44, when the control valves 28A and 28B are not switched, the pilot pressure oil is not supplied to the operation chamber 72a of the hydraulic operation switching valve 72, so that the hydraulic line 35 is damaged and the hydraulic oil flows out. In this case, the hydraulic oil in the bottom chamber 7b is blocked by the pilot operation check valve 73, so that the hydraulic cylinder 7 does not contract and the first arm 8, that is, the front 6 does not descend. Such a holding valve 44 is also provided on the bottom chamber 9b side of the hydraulic cylinder 9 or the bottom chamber 12b side of the hydraulic cylinder 12 where the arm 11 or 14 may be lowered due to breakage of the hydraulic line 37 or 39. Also good.

  In this work machine 55, when the engine of the hydraulic power unit 4 and the pumps 22A, 22B, and 23 are defective, or when the engine must be stopped due to an abnormal power stop such as the engine being stopped due to running out of fuel, FIG. As shown in FIG. 3, the emergency pilot hydraulic line 58A of the companion work machine 56 is connected to the emergency pilot hydraulic line 58 of the work machine 55, and the emergency pilot hydraulic line 57 and couplers 60, 61 for relaying. Connection is made by coupling 60A and 61A. Then, the pilot valves are operated in the order of the pilot valves 49, 48, 47, and 46, and the hydraulic cylinders 17, 12, 9, and 7 are sequentially operated and stopped. Thereby, as indicated by arrows 83, 84, 85, 86 in FIG. 1, the crushing tool 15, the third arm 14, the second arm 11, and the first arm 8 are lowered in this order, and the crushing tool 15. The articulated front 6 is laid down in the state 6X where has landed.

  The flow of hydraulic oil in this arm lowering operation will be described with reference to FIG. 4 taking an example when the third arm 14 is lowered. First, when the arm 14 is in the standing state, hydraulic pressure is generated in the bottom chamber 12 b due to the weight of the arm 14 and the crushing tool 15. Therefore, the pilot valve 48 is operated to switch the control valve 28A to the right position, and at the same time, the control valve 28B is switched to the left position, and the secondary hydraulic line 39 is communicated with the oil tank 24 through the hydraulic lines 63A and 63B. . As a result, the hydraulic oil generated in the bottom chamber 12b causes the hydraulic oil in the bottom chamber 12b to flow into the hydraulic line 39, the control valves 28A and 28B, the hydraulic lines 63A and 63B, the check valve 66, the hydraulic line 38, It circulates in the flow path of the rod chamber 12a. Further, due to the difference in cross-sectional area between the rod chamber 12a and the bottom chamber 12b, a part of the hydraulic oil flowing out from the bottom chamber 12b does not return to the rod chamber 12a but flows down from the hydraulic lines 63A and 63B to the oil tank 24. Due to the flow of hydraulic oil around the hydraulic cylinder 12, the hydraulic cylinder 12 contracts and the arm 14 descends as indicated by an arrow 84. Similarly, the lowering of the crushing tool 15, the second arm 11, and the first arm 8 causes the hydraulic cylinders 17, 9, and 7 to operate in the lowering direction by the weight of the portion to be rotated.

  As described above, according to this embodiment, the engine of the hydraulic power unit 4 of the work machine 50, the hydraulic pumps 22A and 22B, and the pilot pump 23 are malfunctioned, or the power is abnormally stopped such as when the engine stops due to running out of fuel. Even in the event, the long front can be in a safe resting position.

  Further, when the present invention is implemented, the couplers 61 and 61A are directly connected by lengthening the emergency pilot hydraulic line 58 of the work machine 55 or the emergency pilot hydraulic line 58A of the companion work machine 56. Thus, the pilot pressure oil can be supplied from the companion work machine 56 to the work machine 55. However, in this embodiment, since the emergency pilot hydraulic pipe 57 for relay is provided and the emergency pilot hydraulic pipes 58 and 58A are indirectly connected, the emergency pilot hydraulic pipe is used. There is no need to prepare a long path 58, 58A, and an emergency pilot hydraulic line 57 for relay having a suitable length is prepared as necessary, thereby making a suitable connection to the work site. be able to. Also, a plurality of relay emergency hydraulic pipes 57 may be prepared and added according to the distance between the work machines 55 and 56.

  Although the present invention has been described with reference to one embodiment, the present invention can be applied to the pilot valves 46 to 50 that operate the pilot valve with an electric lever and supply pilot pressure oil to the control valve. is there.

  1: Lower traveling body, 2: Turning device, 3: Upper turning body, 4: Hydraulic power unit, 5: Cab, 6: Articulated front, 7, 9, 12, 17: Hydraulic cylinder, 8: First arm, 11: 2nd arm, 14: 3rd arm, 15: Crushing tool, 22A, 22B: Main hydraulic pump, 23: Pilot pump, 24: Oil tank, 25: Control valve assembly, 26A, 26B, 27, 28A , 28B, 29-32: control valve, 34-41: hydraulic line, 43, 43A, 43B: relief valve device, 44: holding valve, 46-50: hydraulically operated pilot valve, 52, 52A: check valve 53, 53A: Discharge pipe, 54, 54A: Gate lock valve, 55: Working machine, 56: Companion working machine, 57: Emergency pilot hydraulic pipe for relay, 58, 58A: Emergency pad Lot hydraulic line, 60, 60A, 61, 61A: coupler, 64, 65: relief valve, 66, 67: check valve, 72: hydraulically operated switching valve, 73: pilot operated check valve, 74: check Valve, 75: Relief valve, 76: Pilot line

Claims (2)

A multi-jointed long front mounted on the upper swing body of the work implement, connected to a plurality of arms by a hydraulic cylinder so as to be rotatable, and a work tool attached to the tip arm;
A control valve for operating the hydraulic cylinder, a pilot valve for operating the control valve, and a pilot pump for supplying pilot pressure oil to the control valve via the pilot valve;
A relief valve provided between a hydraulic line between the control valve and the hydraulic cylinder and an oil tank, and a reverse valve provided in parallel with the relief valve for preventing excessive hydraulic pressure in the hydraulic line. In the descent device at the time of abnormal power stop of the long front in a work machine equipped with a stop valve,
A check valve provided between the pilot pump and the pilot valve to prevent backflow of pilot pressure oil to the pilot pump;
An emergency pilot hydraulic line provided by branching from between the check valve and the pilot valve to prevent backflow of pilot pressure oil to the pilot pump;
A descent device for abnormal power stop at a long front, comprising a coupler provided in the emergency pilot hydraulic line so as to be able to take in pilot pressure oil from the outside. A multi-jointed long front mounted on the upper swing body of the work implement, connected to a plurality of arms by a hydraulic cylinder so as to be rotatable, and a work tool attached to the tip arm;
A control valve for operating the hydraulic cylinder, a pilot valve for operating the control valve, and a pilot pump for supplying pilot pressure oil to the control valve via the pilot valve;
A relief valve provided between a hydraulic line between the control valve and the hydraulic cylinder and an oil tank, and a reverse valve provided in parallel with the relief valve for preventing excessive hydraulic pressure in the hydraulic line. In the descent method at the time of abnormal power stop of the long front in a work machine equipped with a stop valve,
A check valve provided between the pilot pump and the pilot valve, which prevents a backflow of pilot pressure oil to the pilot pump; and the check valve and the pilot which prevents a backflow of pilot pressure oil to the pilot pump There is provided an emergency pilot hydraulic line branched from the valve and a coupler provided in the emergency pilot hydraulic line so that pilot pressure oil can be taken from the outside. With
The companion work machine of the work machine is also provided with an emergency pilot hydraulic line and a coupler branched from the check valve and the pilot valve to prevent the backflow of the pilot pressure oil to its own pilot pump. Leave
When the power of the work machine is stopped, the emergency pilot hydraulic line of the work machine is connected to the emergency pilot hydraulic line of the work machine, and the emergency pilot hydraulic line of the companion work machine is set to these emergency pilot hydraulic lines, respectively. Connect directly through the provided coupler, or indirectly through a relay emergency pilot hydraulic line and coupler,
By operating the pilot pump of the companion work machine, the pilot pressure oil from the pilot pump of the companion work machine passes through the emergency pilot hydraulic pipelines of the companion work machine and the work machine, and the work during the power stop The control valve is supplied to the pilot valve of the machine and can be switched by the operation of the pilot valve of the work machine that is stopped.
It is generated in the oil chamber of the hydraulic cylinder corresponding to the arm by operating the pilot valve of the work implement that has been stopped corresponding to the arm from the upper arm and switching the corresponding control valve. Hydraulic oil is circulated between the bottom chamber and the rod chamber of the hydraulic cylinder, and the corresponding hydraulic cylinder is sequentially operated from the upper arm in the arm lowering direction to lower the long front. The long front power descent method when abnormal power stops.

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