JPH084044A - Interference preventive device of work machine - Google Patents

Abstract

PURPOSE:To distinguish jack up operation from operation other than this and make the interference preventive action of a bucket and an operating room proper by deciding whether or not a boom angle is more than a specific angle. CONSTITUTION:An abnormal intrusion decision sphere and an interference preventive sphere are set from the front of an operating room over to the lower part, and the memory portions 26, 27 of the operation device 23 of a controller are made to memorize this. Also, the tip coordinates of a bucket is calculated at the coordinates operation portion 24 of the operation device 23, and a boom angle deciding portion 25, it is decided whether or not a boom angle alpha is more than a specific angle. In addition, at a comparison operation portion 29, it is decided whether or not the bucket tip coordinates have intruded into each sphere, and when the tip of the bucket has intruded into the abnormal intrusion decision sphere, if it is alpha>=k, it is regarded as abnormal intrusion, and the interference direction action of a work machine is kept prohibited even after abnormal intrusion decision sphere retreat. Meanwhile, if it is alpha<k, it is decided as jack up operation, and automatic return to normal operation is made at the time point of the abnormal intrusion decision sphere retreat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interference preventing device for a working machine, which automatically stops the operation of the working machine when the working machine approaches the driver's cab, and avoids a collision between the two. The present invention relates to an interference prevention device for a working machine, which is suitable for use in a construction machine such as a small swing hydraulic excavator.

[0002]

2. Description of the Related Art FIGS. 12 to 14 are disclosed in Japanese Patent Application Laid-Open No. 5-272155 as a prior art of an interference prevention device for a work machine of this type. FIG. 12 is a side view of a hydraulic excavator, and FIG. FIG. 14 is a plan view thereof, and FIG. 14 is a side view showing the relationship between the bucket and the interference prevention area and emergency stop area set in the hydraulic excavator.

In FIGS. 12 and 13, reference numeral 1 denotes a traveling body, 2
Is a revolving structure having a driver's cab 2a and arranged above the traveling structure 1. The traveling structure 1 and the revolving structure 2 form a main body of the hydraulic excavator. 3 is a driver's cab 2a in the revolving structure 2
The first boom, which is rotatably connected to the right side of the
The second boom 5 rotatably connected to the tip of the boom 3
Is an arm rotatably connected to the tip of the second boom, 6
Is a bucket rotatably connected to the tip of the arm 5, and these booms 3, 4 and the arm 5 and the bucket 6 are
Constitutes the working machine 7. 8 is a boom cylinder for driving the first boom 3, 9 is an offset cylinder for driving the second boom 4, 10 is an arm cylinder for driving the arm 5, 11 is a bucket cylinder for driving the bucket 6, and is shown in FIG. Thus, the second boom 4 uses the offset cylinder 9 to connect the arm 5 and the bucket 6 to the first boom 3
Translate laterally with respect to. Each of these cylinders 8,
9, 10 and 11 are operated by operating levers and operating pedals (neither shown) arranged in the cab 2a. When an operator operates these operating levers or operating pedals appropriately, an instruction signal corresponding to the operation amount is given. The amount of pressure oil supplied to each cylinder 8, 9, 10, 11 is controlled based on Reference numeral 12 is a boom angle sensor provided on the fulcrum portion P of the first boom 3, and detects a relative angle between the swing body 2 and the first boom 3. Further, 13 is an offset angle sensor provided at a fulcrum portion of the second boom 4, and
And a relative angle between the second boom 4 and the second boom 4 is detected. Further, 14 is an arm angle sensor provided at a fulcrum of the arm 5, and detects a relative angle between the second boom 4 and the arm 5.

In FIG. 14, reference numeral 15 is an interference prevention region set from the front to the lower side of the driver's cab 2a, 16 is an emergency stop region set inside the interference prevention region 15 only in front of the driver's cab 2a, The interference prevention area 15 and the emergency stop area 16 are stored in a controller (not shown). This controller is provided with the sensors 12, 13,
Each angle signal detected by 14 is input, the posture of the work implement 7 is obtained from each angle signal, and when it is determined that the bucket 6 has entered the interference prevention area 15, an instruction signal from the operation lever or operation pedal is input. Regardless, the operation of each part of the working machine 7 is automatically stopped so that the bucket 6 does not come closer to the cab 2a.

That is, when the offset cylinder 9 is left offset and the bucket 6 is in front of the operator's cab 2a, the arm 5 is pulled (clouded) and the first boom 3 is moved.
The bucket 6 moves in a direction approaching the operator's cab 2a when a single raising operation or a combined operation is performed, but a solenoid valve is provided in the left offset pilot line of the hydraulic circuit, the boom raising pilot line, and the arm pulling pilot line. When the bucket 6 enters the interference prevention area 15, the controller outputs a control signal for operating each solenoid valve, and thereby the pressure oil in each pilot line described above is shut off. The left offset operation, the arm pulling operation, and the first boom raising operation are prohibited. Further, when the bucket 6 enters the emergency stop region 16 beyond the interference prevention region 15 due to a defective solenoid valve or the like, another solenoid valve provided in the conduit between the pilot pump and each directional switching valve Is operated by a control signal from the controller, the working machine 7 is urgently stopped regardless of the operation of the operation lever and the operation pedal, because the pressure oil supply from the pilot pump to each directional control valve is interrupted.

[0006]

By the way, in the above-mentioned conventional interference preventing device for a working machine, as shown in FIG. 14, the arm 5 is grounded in a folded posture, and in this state, the boom cylinder 8 is contracted and the boom is boomed. When the lowering operation of 3 is performed, the front of the traveling body 1 is lifted by the jack-up operation of the work implement 7, but when the traveling body 1 is lifted to a certain extent, the load of the pipe line connected to the rod side of the arm cylinder 10 is Since the pressure is increased and the relief valve provided in the pipeline is operated, the arm cylinder 10 is extended and the arm 5 moves in the pulling direction. At this time, if the bucket 6 is in the vicinity of the lower portion of the operator's cab 2a, the bucket 6 moves in the direction of the arrow in the figure and scratches the emergency stop region 16, so that all operations of the operation lever and the operation pedal are prohibited. Become. Therefore, in such a case, despite the fact that each part is functioning normally, it is considered that there is some kind of defect and all operations are prohibited. There was a problem that a great deal of time and labor was required to restore it.

The present invention has been made in view of the circumstances of the prior art as described above, and an object thereof is to make it possible to differentiate a jack-up operation from other operations and properly prevent interference between a bucket and a driver's cab. An object of the present invention is to provide an interference prevention device for a working machine.

[0008]

In order to achieve the above object, the present invention provides a main body having an operator's cab, and a first boom rotatably provided on the side of the operator's cab of the main body. A second boom movably connected to the first boom by an offset cylinder in a lateral direction, an arm rotatably connected to the second boom, and a arm rotatably with respect to the arm. The buckets are connected to each other, an actuator for driving a working machine including the first and second booms, an arm and a bucket, and at least a front side of the operator's cab and a side side of the first boom. A controller for determining whether or not the bucket has entered the interference prevention area, and when the bucket enters the interference prevention area, In the interference preventing device for a working machine, which prohibits the operation in the direction of interfering with the transfer chamber and allows the operation of the working machine in the interference direction when the bucket is retracted from the interference preventing area, A boom formed by a horizontal line in front of the main body and the first boom when an abnormal intrusion determination area is set inside the interference prevention area and the bucket enters the abnormal intrusion determination area beyond the interference prevention area. Only when the angle is equal to or larger than the specific angle, the operation of the working machine in the interference direction is continuously prohibited even after the bucket is retracted from the abnormal intrusion determination area.

[0009]

When the pulling operation of the arm and the raising operation of the first boom are performed individually or in combination while the offset cylinder is left offset, the tip of the bucket moves toward the operator's cab, and the sensor and valve If the equipment is functioning normally, it will automatically stop within the interference prevention area set around the operator's cab, and if the solenoid valve has a defect such as stick, abnormal intrusion set inside the interference prevention area. Enter the judgment area. At this time, when the boom angle is equal to or larger than the specific angle, it is determined that the work is abnormally intruded, and the operation of the work machine in the interference direction is continuously prohibited even after the bucket is retracted from the abnormal intrusion determination region. Also, if you ground the arm in a folded position and perform a jack-up operation in this state,
The main body stops after being lifted halfway, and instead the arm pulls and the bucket enters the abnormal intrusion determination area, but in this case, the bucket was not determined to be an abnormal intrusion and the bucket was evacuated from the abnormal intrusion determination area. At this point, the work machine is allowed to move in the interference direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a side view of a hydraulic excavator equipped with an interference prevention device for a working machine according to an embodiment of the present invention, FIG. 2 is a side view of the hydraulic excavator during a jack-up operation, and FIG. 3 is an interference prevention device of FIG. Is a block diagram showing the overall configuration of FIG. 4, FIG. 4 is a circuit diagram showing a hydraulic drive circuit, and FIGS. 5 to 11 are flowcharts showing the processing contents of the arithmetic unit.
The same reference numerals are given to the portions corresponding to.

As shown in FIG. 1, in the hydraulic excavator according to this embodiment, an interference prevention region 21 is set from the front to the lower part of the operator's cab 2a, and an abnormal intrusion determination region 22 is set inside the interference prevention region 21. These areas 21 and 22 are stored in the arithmetic unit of the controller described later. The interference prevention area 21 includes an upper interference prevention area 21a extending linearly forward of the upper portion of the cab 2a,
The lower interference prevention region 21b extends in an arc shape from the lower front side to the lower side of the operator's cab 2a, and the lower interference prevention region 21b has a curved shape with the rotation fulcrum P of the first boom 3 or its vicinity as a central axis. Has been formed. That is, when the boundary line between the normal area and the interference prevention area 21 is Z1, and the boundary line between the interference prevention area 21 and the abnormal intrusion determination area 22 is Z2, these boundary lines Z1, Z2 is formed concentrically with the rotation fulcrum P as the approximate center.

In FIG. 3, reference numerals 12, 13, and 14 denote the boom angle sensor, the offset angle sensor, and the arm angle sensor, respectively, and the relative angle signals between the working machine members detected by these sensors 12, 13, and 14, respectively. θ1, θ2, θ
3 is input to the arithmetic unit 23 built in the controller. The arithmetic unit 23 calculates the coordinate of the tip of the bucket 6 from the coordinate of the predetermined point on the working machine 7, for example, the tip of the arm 5, based on the angle signals θ1, θ2, θ3.
4 and the boom angle α detected by the boom angle sensor 12 (the horizontal line extending in front of the revolving structure 2 and the first
A boom angle determination unit 25 that determines whether or not the angle formed by the center line of the boom 3) is a specific angle k or more, an interference prevention region storage unit 26 and an abnormal intrusion determination region storage unit 27 that store the above-described regions. And a comparison calculation unit 29 that determines whether or not the bucket tip coordinates calculated by the coordinate calculation unit 24 are in the storage units 26 and 27, and outputs a predetermined control signal according to the result, and a comparison calculation. The drive control unit 30 outputs a predetermined control signal to the hydraulic drive circuit 31 based on the control signal from the unit 29. The hydraulic drive circuit 31 receives, in addition to the control signal from the drive control unit 30, an operating means for operating the working machine 7 arranged in the cab 2a, for example, an instruction signal from an operating lever 32, The amount of hydraulic oil supplied to each of the cylinders 8 to 11 is controlled based on these signals. When the bucket tip coordinates are calculated, for example, a coordinate system having the center of rotation P of the revolving unit 2 and the first boom 3 as the origin is set in advance, and the angle signals θ1, θ2, respectively.
The coordinate value of the tip of the arm 5 in this coordinate system may be calculated from θ3, and the coordinate value of the tip of the bucket 6 may be calculated from the coordinate value of the arm tip.

As shown in FIG. 4, the hydraulic drive circuit 31 is provided.
Are a hydraulic pump 33 and a pilot pump 34 driven by an engine, a boom directional control valve 35 for controlling the flow of hydraulic oil supplied from the hydraulic pump 33 to the cylinders 8, 9 and 10, and an offset directional control valve. 36, an arm direction switching valve 37, a boom pilot valve 38 for operating the cylinders 8, 9 and 10, an offset pilot valve 39, an arm pilot valve 40, etc., and a bucket cylinder 11, a traveling motor, etc. Other actuators are omitted from the drawing. Each pilot valve 38, 39, 40 has a left chamber and a right chamber which communicate with the pilot pump 34, and the pressure oil discharged from the pilot pump 34 is converted into an instruction signal from the operation lever 32. Depending on these, these are supplied to the left or right chamber.

The boom direction switching valve 35 has pilot chambers on both left and right sides.
5 left pilot chamber and the boom pilot valve 3
The chamber on the left side of 8 is connected by a boom raising pilot line 41, and the chamber on the right side of the direction switching valve for boom 35 and the chamber on the right side of the pilot valve for boom 38 are connected by a boom lowering pilot line 42. There is. The offset directional control valve 36 also has pilot chambers on both left and right sides.
The pilot chamber on the left side of 6 and the chamber on the left side of the offset pilot valve 39 are arranged in the right offset pilot line 43.
The pilot chamber on the right side of the offset directional control valve 36 and the chamber on the right side of the offset pilot valve 39 are connected by a left offset pilot conduit 44. Further, the arm directional control valve 37 also has pilot chambers on both left and right sides. The pilot chamber on the left side of the arm directional control valve 37 and the chamber on the left side of the arm pilot valve 40 are arm pull pilot pipes. Road 45
And the right pilot chamber of the arm directional control valve 37 and the right chamber of the arm pilot valve 40 are connected by an arm pushing pilot conduit 46.

An electromagnetic proportional pressure reducing valve 47 for a boom is provided in the boom raising pilot line 41, and an electromagnetic proportional pressure reducing valve 48 for an arm is provided in the arm pulling pilot line 45, respectively. 47 and 48 have ports connected to the tank. These electromagnetic proportional pressure reducing valves 47 and 48 are used for the drive control unit 30 of the arithmetic unit 23.
Is operated in proportion to the current value of the control signal output from
Normally, when the maximum level current Ia is input to fully open the boom raising pilot line 41 and the arm pulling pilot line 45 and the current Ib having the minimum current value is input as the control signal, the boom raising pilot line 41 is input. Shut off the pressure oil from the arm pull pilot line 45 and return it to the tank.
When a current Ic whose current value is between the maximum level and the minimum level is input as the control signal, the boom raising pilot line 4
1 and the arm pulling pilot line 45 to reduce the pressure oil to reduce the pilot pressure. On the other hand, an offset electromagnetic switching valve 49 is provided in the left offset pilot conduit 44, and the electromagnetic switching valve 49 has a port connected to the tank. This electromagnetic switching valve 49 is also the arithmetic unit 2
The switching operation is performed by the control signal output from the drive control unit 30 of No. 3, and only when the control signal is input, the pressure oil in the left offset pilot conduit 44 is shut off and returned to the tank. Relief valves are provided in the bottom side and rod side pipelines of the cylinders 8, 9 and 10, respectively, and these relief valves operate when the load pressure in the corresponding pipelines increases, Return the pressure oil in the line to the tank.

Next, the operation of this embodiment will be mainly described with reference to FIGS.
This will be described with reference to the flowchart shown in. For normal operation in which there is no risk of contact between the tip of the bucket 6 and the cab 2a, that is, when the bucket 6 is located outside the interference prevention area 21 set around the cab 2a, The arm electromagnetic proportional pressure reducing valves 47, 48 and the offset electromagnetic switching valve 49 are all in the positions shown in FIG. In this state, for example, when the boom operating lever 32 is tilted to the left side in FIG. 4, the pressure oil discharged from the pilot pump 34 flows from the chamber on the left side of the boom pilot valve 38 to the boom raising pilot conduit 41 and the boom. Solenoid proportional pressure reducing valve 4
After being supplied to the pilot chamber on the left side of the boom direction switching valve 35 via 7, the boom direction switching valve 35 starts to operate. Then, when the boom direction switching valve 35 is switched from the neutral position to the left side position, the pressure oil of the hydraulic pump 33 is supplied to the bottom side of the boom cylinder 8 via the boom direction switching valve 35, and the boom cylinder 8 extends. Then, the first boom 3 rises. On the contrary, when the boom operation lever 32 is tilted to the right side in FIG. 4, the pilot pump 3
The pressure oil discharged from No. 4 is supplied from the chamber on the right side of the boom pilot valve 38 to the pilot chamber on the right side of the boom direction switching valve 35 via the boom lowering pilot conduit 42, and the boom direction switching valve 35 operates. Start. Then, when the boom direction switching valve 35 is switched from the neutral position to the right position, the pressure oil of the hydraulic pump 33 is supplied to the rod side of the boom cylinder 8 via the boom direction switching valve 35, and the boom cylinder 8 expands and contracts. The first boom 3 descends. Similarly, the offset cylinder 9 expands and contracts according to the amount of operation of the offset operation lever 32, and the arm 5 and the bucket 6 are laterally right- or left-offset with respect to the first boom 3, and the operation lever 32 is also operated. The arm cylinder 10 expands and contracts in accordance with the operation amount of, and the arm 5 is pulled or pushed.

At this time, the arithmetic unit 23 first determines whether or not the abnormality processing flag is set, as shown in step S-1 of FIG. 5, and if the flag is not set, the procedure is performed. At S-2, the relative angle signals θ1, θ2, θ3 from the boom angle sensor 12, the offset angle sensor 13, and the arm angle sensor 14 are input to the coordinate calculation unit 24, and then at step S-3, the relative angle signals θ1, θ.
After calculating the coordinates of the tip of the arm 5 from 2, 3
At -4, the bucket tip coordinates are calculated from the arm tip coordinates. Next, in step S-5, the comparison calculation unit 29 compares the bucket tip coordinates with the abnormal intrusion determination area storage unit 27, and determines whether the tip of the bucket 6 is inside the abnormal intrusion determination area 22. In other words, it is determined whether the tip of the bucket 6 has entered the boundary line Z2.

When the result of the determination in step S-5 is NO, that is, when the tip of the bucket 6 has not entered the abnormal intrusion determination area 22, the process proceeds to step S-6, and the comparison calculation section 29 coordinates. The bucket tip coordinates calculated by the computing section 24 and the interference prevention area storage section 26 are compared to determine whether or not the tip of the bucket 6 is inside the interference prevention area 21, that is,
It is determined whether the tip of the bucket 6 is between the boundary line Z1 and the boundary line Z2. When the determination result in step S-6 is NO, the tip of the bucket 6 is outside the interference prevention area 21, and in this case, the process proceeds to step S-7 and the normal processing is performed. In the case of this normal processing, as shown in FIG. 6, the drive control unit 30 outputs the maximum level current Ia to the boom electromagnetic proportional pressure reducing valve 47 and the arm electromagnetic proportional pressure reducing valve 48, and the offset electromagnetic switching valve 49. No switching signal is output to the boom raising pilot line 41, the arm pulling pilot line 45, and the left offset pilot line 44 are fully opened. Therefore, the cylinders 8, 9 and 10 perform normal operation according to the operation amount of the corresponding operation lever 32.

When the result of the determination in step S-6 is YES, the process proceeds to step S-8, and the comparison calculation section 29 determines whether or not the bucket tip coordinates are within the lower interference prevention area 21b. When the result of the determination in step S-8 is NO, that is, when the tip of the bucket 6 is in the upper interference prevention area 21a, the process proceeds to step S-9 and the stop process A is performed. In this case, as shown in FIG. 7, the drive control unit 30 controls the boom electromagnetic proportional pressure reducing valve 47 and the arm electromagnetic proportional pressure reducing valve 4.
After outputting a current Ic having a current value between the maximum level and the minimum level to 8, the minimum level current Ib is output, whereby the pressure oil in the boom raising pilot line 41 and the arm pulling pilot line 45 is squeezed. After reducing the pilot pressure by means of this, the pressure oil in these pilot conduits 41, 45 is shut off and returned to the tank. The drive control unit 30 also outputs a switching signal to the offset electromagnetic switching valve 49 to shut off the pressure oil in the left offset pilot conduit 44 and return it to the tank. Therefore, the operation levers 32 are operated in a direction in which the tip of the bucket 6 approaches the operator's cab 2a, and pressure oil is supplied from the pilot pump 34 to the boom raising pilot conduit 41, the arm pulling pilot conduit 45, and the left offset pilot conduit 44. Even if supplied, since the pilot pressure does not build up in these pipe lines 41, 44, 45, the working machine 7 automatically stops and the first
The raising operation of the boom 3, the pulling operation of the arm 5, and the left offset operation are prohibited.

On the other hand, when the result of the determination in step S-8 is YES, that is, when the tip of the bucket 6 is in the lower interference prevention area 21b, the process proceeds to step S-10 and the stop processing B is performed. . In this case, as shown in FIG. 8, the drive control unit 30 outputs the maximum level current Ia to the boom proportional electromagnetic pressure reducing valve 47 to fully open the boom raising pilot conduit 41, but the arm proportional electromagnetic reducing valve 48. The minimum level current Ib is output to the offset solenoid switching valve 4
A switching signal is output to 9 and the arm pull pilot line 45
And the pressure oil in the left offset pilot line 44 is shut off and returned to the tank. Therefore, the tip of the bucket 6 is located in the cab 2
Even if each operation lever 32 is operated in the direction of approaching a, the pulling operation of the arm 5 and the left offset operation are prohibited, and the working machine 7 is automatically stopped, but the raising operation and the lowering operation of the first boom 3 are included. Other operations are permitted. At that time, the first
When the boom 3 is moved up or down, the tip of the bucket 6 rotates within the lower interference prevention area 21b around the rotation fulcrum P of the first boom 3, so the operation of the first boom 3 continues after the automatic stop. Even if it does, the tip of the bucket 6 does not interfere with the cab 2a.

When the result of the determination in step S-5 is YES,
That is, when the tip of the bucket 6 is within the abnormal intrusion determination area 22, the process proceeds to step S-11, and the boom angle determination unit 2
5 determines whether or not the boom angle α of the first boom 3 is equal to or greater than the specific angle k. When the determination result in step S-11 is NO, that is, when the first boom 3 is lowered until the boom angle α becomes smaller than k as in the jack-up operation, the process proceeds to step S-12 and the stop processing is performed. C is performed. In this case, as shown in FIG. 9, the drive control unit 30 outputs a minimum level current Ib to the boom electromagnetic proportional pressure reducing valve 47 and the arm electromagnetic proportional pressure reducing valve 48, and outputs a switching signal to the offset electromagnetic switching valve 49. Is output, and the stop processing A described above is output.
In the same manner as the above, all operations in the interference direction are prohibited, the work implement 7 is stopped urgently, and an alarm such as sounding a buzzer or lighting a lamp is issued to notify the operator of the abnormal intrusion determination area 2
Notify that you have entered 2. Therefore, as shown in FIG. 2, during the jack-up operation, after the traveling body 1 is partially lifted, the relief valve provided in the rod-side conduit of the arm cylinder 10 operates to prevent the bucket 6 from interfering with the lower portion. Abnormal intrusion determination area 22 beyond the area 21b
Even if it invades inside, in this case, the stop processing C is performed without being considered as an abnormal intrusion. The stop process A, the stop process B, and the stop process C described above are automatically released at the position where the tip of the bucket 6 is retracted to the outside of the interference prevention area 21, and the above-described normal process is performed again.

On the other hand, the determination result in step S-11 is YES.
In other words, if the tip of the bucket 6 crosses the boundary line Z2 and enters the abnormal intrusion determination region 22 due to a defect in each of the sensors 12 to 14, the electromagnetic proportional pressure reducing valves 47, 48, the electromagnetic switching valve 49, or the like. Then, the procedure proceeds to step S-13, and the abnormality processing is performed. In this case, as shown in FIG. 10, the drive control unit 30 outputs a minimum level current Ib to the boom electromagnetic proportional pressure reducing valve 47 and the arm electromagnetic proportional pressure reducing valve 48, and outputs a switching signal to the offset electromagnetic switching valve 49. Is output, and all the operations in the interference direction are prohibited, and the work implement 7 is stopped urgently, as in the stop processing A described above. Further, the abnormality processing flag is set, and an alarm such as sounding a buzzer or lighting a lamp is issued to notify the operator that there is some abnormality.

When the abnormality processing flag is set in step S-13, even if the tip end of the bucket 6 is retracted from the abnormal intrusion determination area 22 to the outside of the interference prevention area 21, the raising operation of the first boom 3 is performed. The pulling operation and the left offset operation of the arm 5 remain prohibited, and normal work cannot be performed. In such a case, with the engine stopped, the sensor or valve causing the defect is replaced with a normal one, and then the engine is restarted to return to step S-1. As described above, this procedure S
In -1, it is determined whether or not the flag for the abnormality processing is set. In this case, since the flag remains set, the procedure proceeds from step S-1 to step S-14 and the restoration processing is performed. As shown in FIG. 11, in the return processing, the drive control unit 30 causes the boom electromagnetic proportional pressure reducing valve 4 to operate.
7 and the electromagnetic proportional pressure reducing valve 48 for the arm have a minimum level current I.
By outputting b and a switching signal to the electromagnetic switching valve for offset 49, the state in which all the operations in the interference direction are prohibited is maintained, and, for example, when the abnormality recovery signal is turned on from the reset switch, the abnormality processing is performed. The flag is reset, the return process is completed, and the process returns to step S-2.

As described above, in the above embodiment, if there is any defect in the sensor or valves, the bucket 6
Is automatically stopped in the abnormal intrusion determination area 22, and the operation of the work implement 7 in the interference direction is continuously prohibited until the return processing is performed, so that the bucket 6 can be reliably prevented from colliding with the operator cab 2a. . Further, even if the tip of the bucket 6 enters the abnormal intrusion determination area 22 during the jack-up operation, in this case, it is not determined to be an abnormal intrusion, and a normal operation is performed when the tip of the bucket 6 is retracted from the abnormal intrusion determination area 22. Since the automatic recovery is performed, the waste of spending a great deal of time and labor for repairing the abnormality can be eliminated and the work efficiency can be improved even though each component is functioning normally.

Further, the tip of the bucket 6 has an interference prevention area 2
Even when the first boom 3 is automatically stopped by invading the first boom 3, if the tip of the bucket 6 is located in the lower interference prevention area 21b set from the lower front side to the lower side of the cab 2a, the first boom 3 is raised or lowered. Bucket 6 even if operated
Since the front end of the first boom rotates inside the curved lower interference prevention area 21b and does not interfere with the cab 2a, the raising and lowering operations of the first boom 3 can be continued without interrupting the work. Furthermore, since the curved shape of the lower interference prevention area 21b enables the lowering operation of the first boom 3 after the automatic stop, it is not necessary to provide a solenoid valve for prohibiting the boom lowering operation in the boom lowering pilot conduit 42. The increase in cost can be suppressed.

[0026]

As described above, according to the present invention,
An abnormal intrusion determination area is set inside the interference prevention area that keeps the work machine from operating in the interference direction.When jacking up, even if the tip of the bucket intrudes into the abnormal intrusion determination area, Therefore, the jack-up operation and the other operations are differentiated, and it is possible to provide a work machine interference prevention device with high work efficiency.

[Brief description of drawings]

FIG. 1 is a side view of a hydraulic excavator including an interference prevention device for a working machine according to an embodiment of the present invention.

FIG. 2 is a side view of the hydraulic excavator during a jack-up operation.

FIG. 3 is a block diagram showing an overall configuration of the interference prevention device of FIG.

FIG. 4 is a circuit diagram showing a hydraulic drive circuit provided in the interference prevention device of FIG.

5 is a flowchart showing processing contents of an arithmetic unit provided in the interference prevention device of FIG.

6 is a flowchart showing a normal process of the arithmetic unit of FIG.

7 is a flowchart showing a stop process A of the arithmetic device of FIG.

8 is a flowchart showing a stop process B of the arithmetic device of FIG.

9 is a flowchart showing a stop process C of the arithmetic device of FIG.

10 is a flowchart showing an abnormal process of the arithmetic device of FIG.

11 is a flowchart showing a return process of the arithmetic device of FIG.

FIG. 12 is a side view of a hydraulic excavator including an interference prevention device for a working machine according to a conventional example.

FIG. 13 is a plan view of the hydraulic excavator.

FIG. 14 is a plan view showing the relationship between the bucket and the interference prevention area and the emergency stop area set in the hydraulic excavator.

[Explanation of symbols]

 2 Revolving structure 2a Operator's cab 3 1st boom 4 2nd boom 5 Arm 6 Bucket 7 Working machine 8 Boom cylinder 9 Offset cylinder 10 Arm cylinder 12 Boom angle sensor 13 Offset angle sensor 14 Arm angle sensor 21 Interference prevention area 21a Top interference prevention Area 21b Lower interference prevention area 22 Abnormal intrusion determination area 23 Arithmetic device 24 Coordinate operation section 25 Boom angle determination section 26 Interference prevention area storage section 27 Abnormal intrusion determination area storage section 29 Comparison operation section 30 Drive control section 31 Hydraulic drive circuit 32 Operation Lever 47 Electromagnetic proportional pressure reducing valve for boom 48 Electromagnetic proportional pressure reducing valve for arm 49 Magnetic switching valve for offset

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koji Nishimura, 650 Jinrachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory (72) Inventor Shudo Yamada 20 Ishigane, Toyama-shi, Toyama Prefecture (72) Inventor Takashi Matsuda 20 Ishigane Co., Ltd., Toyama City, Toyama Prefecture (72) Inventor Toshiyuki Ishizaka 20 Ishigane Co., Ltd., Toyama City, Toyama Prefecture

Claims (2)

[Claims] 1. A main body having a cab, a first boom rotatably provided on a side of the cab of the main body, and a lateral movement by an offset cylinder with respect to the first boom. A second boom connected to the second boom; an arm rotatably connected to the second boom; a bucket rotatably connected to the arm; An actuator for driving a working machine configured with a bucket, and an interference prevention area set at least in front of the operator's cab and on a side facing the first boom are stored, and the bucket is stored in the interference prevention area. A controller that determines whether the bucket has entered, and when the bucket enters the interference prevention area, prohibits an operation in a direction in which the work machine interferes with the cab, and the bucket is When retracted from the interference prevention area, in the interference prevention device of the working machine, which allows the operation of the working machine in the interference direction, an abnormal intrusion determination area is set inside the interference prevention area,
Only when the boom angle formed by the horizontal line in front of the main body and the first boom is equal to or greater than a specific angle when the bucket enters the abnormal intrusion determination area beyond the interference prevention area, An interference preventing device for a work machine, wherein the operation of the work machine in the interference direction is continuously prohibited even after the work machine is retreated from the abnormal intrusion determination area. 2. The interference prevention region according to claim 1, wherein the interference prevention region is set in a curved shape from the lower front side to the lower side of the cab, and the center axis of the curved face and the rotation fulcrum of the first boom are substantially formed. An interference prevention device for working machines characterized by matching.