JPH1121934A - Backhoe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backhoe, in which a feeling of physical disorder on operation is solved at the lifting operation of a boom. SOLUTION: A first restraining surface A1 and a second restraining surface A3 on the side fronter than the first restraining surface A1 are installed so that a bucket is not brought into contact with the frame of a driving section 15, and the lifting operation of a boom 4 is conducted when there is the elevation command of the boom 4 on the second restraining surface and the side fronter than the second restraining surface. When there is the elevation command of the boom 4 when the boom 4 is placed on the first restraining surface A1, the bucket is moved to the earth removal side by an arm 5 once, and the elevation operation of the boom 4 is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing a backhoe from coming into contact with an outer frame covering an operating portion and a bucket of the backhoe device.

[0002]

2. Description of the Related Art In a backhoe, in order to avoid contact between an outer frame covering a driving unit and a bucket, a traction surface is assumed, and the operation of pushing a bucket over the traction surface is automatically stopped. Has become. Then, when the bucket is positioned on the tread surface and there is a command to raise the boom, the bucket is temporarily moved to the earth discharging side in order to prevent the bucket from intruding into the operation section side beyond the tread surface. And then began to rise.

[0003]

In the above case, although the operation performed by the driver is merely an operation of raising the boom, the bucket first moves to the earth discharging side. It was undeniable that there was a sense of incongruity in the operation. SUMMARY OF THE INVENTION An object of the present invention is to avoid an uncomfortable operation on the restraint surface as described above.

[0004]

[Means for Solving the Problems]

[Structure] A characteristic structure of the invention according to claim 1 includes a position sensor for detecting a position of a bucket, and a control means for controlling the operation of the bucket based on the detection of the position sensor. Assuming a first restraint surface that can prevent the bucket from contacting the external frame at a spatial position away from the frame by a predetermined distance, and the bucket moves further outward than the first restraint surface toward the scraping side. To prevent approaching the driving section
Assuming a traction surface, when the control means issues an ascending command on the first traction surface, the bucket is moved to the unloading side, and then started to move upward.
If there is an ascent command on the check surface and outside this,
The point is that the bucket is configured to start the raising operation, and the operation and effect are as follows.

[Operation] In other words, two bounce surfaces are provided, and when there is a boom lift command on the second bounce surface located on the side distant from the operating section and outside thereof,
The bucket starts a lifting operation. However, when the bucket enters the first check surface beyond the second check surface due to the necessity of maintenance or the like, the bucket once moves to the earth discharging side and then moves upward even if there is a lift command.

[Effect] As a result, a feeling of strangeness in operation can be reduced.

[Structure] According to a second feature of the present invention, in the first feature of the present invention, the bucket is moved to the squeezing side beyond the second restraining surface by a squeezing command to the arm. The mode is provided with a check mode switching means capable of switching to a state in which the operation is permitted. The operation and effect are as follows.

[Operation] In other words, the driver can operate the bucket to the rake side beyond the second braking surface by the braking mode switching means.

[Effect] Thereby, operability at the time of maintenance or the like can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall side view of a backhoe. A swivel 2 is supported on a traveling device 1 of the rubber crawler type, and a backhoe 3 is provided in front of the swivel 2. The backhoe device 3 includes a boom 4 that is vertically oscillated by a hydraulic cylinder 11, an arm 5 that is oscillated back and forth by a hydraulic cylinder 12, and a bucket 6 that is oscillated by a hydraulic cylinder 13. ing.

The boom 4 of the backhoe device 3 includes a first boom portion 4a which is vertically swung and a first boom portion 4a.
The second boom portion 4b is swingably connected around the axis P1 at the front end of the second boom, and the support bracket 4c is swingably connected around the axis P2 at the front end of the second boom portion 4b. The arm 5 is connected to the support bracket 4c. An interlocking link 8 is laid across the first boom portion 4a and the support bracket 4c to form a parallel quadruple link, and the hydraulic cylinder 7 swings the second boom portion 4b to move the arm 5 and the The bucket 6 is moved left and right in parallel.

As shown in FIGS. 1 and 5, in the swivel base 2, a backhoe device 3 is disposed on the right side, and a driver's seat 14 and an operation unit 15 including right and left operation levers 9, 10 and the like are disposed on the left side. Have been. At the left and right center of the swivel base 2, a vertical partition plate 16 with a window is provided to partition the backhoe device 3 and the operation unit 15, and an upper partition plate 17 along the outside of the swivel base 2 is provided at the upper end of the vertical partition plate 16. Has been fixed. Here, the vertical partition plate 16 and the upper partition plate 17 are referred to as an external frame.

Next, the operation structure of the hydraulic circuit structure, the backhoe device 3, the swivel 2 and the like will be described. As shown in FIG. 2, the control valve 21 of the hydraulic cylinder 11 of the first boom portion 4a (boom 4), the control valve 22 of the hydraulic cylinder 12 of the arm 5, the control valve 23 of the hydraulic cylinder 13 of the bucket 6,
The control valve 24 of the swivel motor 18 of the swivel 2, the control valve 25 of the hydraulic cylinder 7 of the second boom part 4 b, the right traveling device 1
, A control valve 27 of the left traveling device 1, a control valve 28 of a service port (not shown), and a control valve 29 of a hydraulic cylinder 51 for raising and lowering the dozer 19 shown in FIG.
Is provided, and hydraulic oil from the pump 20 is supplied to the control valve 2.
1 to 29.

The control valve 21 of the first boom portion 4a, the control valve 22 of the arm 5, the control valve 23 of the bucket 6, the control valve 24 of the swivel 2 and the control valve 25 of the second boom portion 4b are controlled by a pilot pressure based on pilot pressure. It is an operation type and a neutral return type. The control valves 26 and 27 of the right and left traveling devices 1, the control valve 28 of the service port, and the control valve 29 of the dozer 19 are mechanically operated and neutral return type operated by operation levers (not shown).

As shown in FIG. 3, the right operating lever 9 is configured to be operable in the front, rear, left and right directions, and a pilot valve 31a for generating a pilot pressure by a rear operation of the right operating lever 9;
A pilot valve 31b that generates pilot pressure by operating the right operating lever 9 in front, a pilot valve 33a that generates pilot pressure by operating the right operating lever 9 to the right, and a pilot that generates pilot pressure by operating the right operating lever 9 to the left. A valve 33b is provided.

Similarly, the left operation lever 10 is also configured to be operable in the front, rear, left and right directions. The pilot valve 32a generates a pilot pressure by the rear operation of the left operation lever 10, and the pilot pressure is generated by the front operation of the left operation lever 10. A pilot valve 32b which generates a pilot pressure by operating the left operating lever 10 to the right, and a pilot valve 34b which generates pilot pressure by operating the left operating lever 10 to the left are provided.

As shown in FIG. 3, there is provided an operation pedal 39 which can be freely operated to the left and right, and a pilot valve 35 which generates a pilot pressure by operating the operation pedal 39 to the left.
a, and a pilot valve 35b for generating a pilot pressure by operating the operation pedal 39 to the right. A pilot pump 30 for supplying pilot pressure to the pilot valves 31a to 35b is provided.

As shown in FIGS. 2 and 3, the pilot valves 31a and 31b of the right operating lever 9 and the first boom portion 4a
Control valve 21, the pilot valve 33a of the right operation lever 9,
The control valve 33b and the control valve 23 of the bucket 6 are connected via a pilot oil passage, and the pilot valves 32a and 32b of the left operation lever 10, the control valve 22 of the arm 5, and the pilot valves 34a and 34b of the left operation lever 10 are connected. And the control valve 24 of the swivel 2 are connected via a pilot oil passage. The pilot valves 35a and 35b of the operation pedal 39 and the control valve 25 of the second boom portion 4b are connected via a pilot oil passage.

When the right operating lever 9 is operated backward by the above structure, the pilot pressure from the pilot valve 31a causes
When the control valve 21 is operated on the ascending side of the first boom portion 4a (extending side of the hydraulic cylinder 11) and the right operating lever 9 is operated in advance, the pilot pressure from the pilot valve 31b causes
The control valve 21 is operated on the lowering side of the first boom portion 4a (the contracting side of the hydraulic cylinder 11). When the right operation lever 9 is operated to the right, the control valve 23 is driven by the pilot pressure from the pilot valve 33a to discharge the bucket 6 to the discharging side (the hydraulic cylinder 1).
When the right operating lever 9 is operated to the left and the right operating lever 9 is operated to the left, the control valve 23 is operated to the rake side of the bucket 6 (the extending side of the hydraulic cylinder 13) by the pilot pressure from the pilot valve 33b.

When the left operating lever 10 is operated backward, the control valve 22 is operated to the squeezing side of the arm 5 (extending side of the hydraulic cylinder 12) by the pilot pressure from the pilot valve 32a, and when the left operating lever 10 is operated forward. The control valve 22 is operated to the discharging side of the arm 5 (the contracting side of the hydraulic cylinder 12) by the pilot pressure from the pilot valve 32b. When the left operating lever 10 is operated to the right, the pilot valve 34
When the control valve 24 is operated to the right turning side of the swivel base 2 by the pilot pressure from a and the left operating lever 10 is operated to the left, the control valve 24 is swiveled counterclockwise by the pilot pressure from the pilot valve 34b. It is operated on the side.

When the operation pedal 39 is depressed to the left, the control valve 25 of the second boom portion 4b is operated to the left swing side (extension side of the hydraulic cylinder 7) by the pilot pressure from the pilot valve 35a. When the right stepping operation is performed, the control valve 25 of the second boom portion 4b is operated to the right swing side (the contraction side of the hydraulic cylinder 7) by the pilot pressure from the pilot valve 35b.

As the right and left operation levers 9 and 10 and the operation pedal 39 are largely operated from the neutral position, the pilot valve 3
The pilot pressures 1a to 35b are configured to increase. Thereby, the right and left operation levers 9, 10,
The larger the operation pedal 39 is operated from the neutral position, the larger the pilot pressure of the pilot valves 31a to 35b, and the more the control valves 21 to 25 are operated to the larger flow rate side. That is, as the right and left operation levers 9 and 10 and the operation pedal 39 are operated larger, the hydraulic cylinders 7, 11, 12, and 13 and the turning motor 18 operate at a higher speed.

Next, the first front restraint surface A1, the second front restraint surface A3, the lateral restraint surface A2, and the like set for the swivel 2 will be described. As shown in FIGS. 4 and 5, the vertical partition 1
6, a first front restraint surface A1 that is separated from the front edge portion of the upper partition plate 17 by a predetermined distance ahead of the front edge of the upper partition plate 17, and the first front restraint surface A
Further forward of the second front restraint surface A3 and the vertical partition plate 1
Lateral restraint surface A2 which is separated from the lateral side of 6 by a predetermined distance to the right
Are set in the control device 40 (see FIG. 3).

In this case, when the bucket pin 6a connecting the bucket 6 to the tip of the arm 5 is located on the first front restraint surface A1, the bucket 6 is swung so that the bucket 6 comes closest to the driving unit 15 side. Even so, the first front restraint surface A1 is set such that the tip of the bucket 6 is located on the trajectory C1 separated by a predetermined distance from the front edge of the vertical partition 16 and the front edge of the upper partition 17. I have. When the bucket pin 6a is located on the lateral restraint surface A2, the lateral restraint surface A2 is set such that the left lateral surface of the bucket 6 is located on a locus C2 separated from the vertical partition plate 16 by a predetermined distance.

A surface which is separated from the second front restraint surface A3 and the lateral restraint surface A2 by a predetermined distance forward or to the right is set, and a space between the space and the second front restraint surface A3 and the lateral restraint surface A2 is set. , The front restraint area B1 and the lateral restraint area B2 are set in the control device 40. Front and side restraint surfaces A1, A as described above
3, A2, front and side restraint areas B1 and B2 are set for the swivel base 2 and move together with the swivel base 2 as the swivel base 2 turns. .

As shown in FIGS. 1 and 4, a connecting portion between the swivel base 2 and the first boom portion 4a has a first
Angle sensor 36 for detecting the vertical angle of boom portion 4a
Is provided at a connection portion between the first and second boom portions 4a and 4b, and the second boom portion 4b with respect to the first boom portion 4a is provided.
Is provided with an angle sensor 37 for detecting the left-right angle of the camera. The connecting portion between the support bracket 4c and the arm 5 has a second
An angle sensor 38 for detecting the front-rear angle of the arm 5 with respect to the boom portion 4b is provided. These angle sensors 36, 37, 38 are called position sensors.

The angle sensors 36, 37, 3 as described above
8 is input to the control device 40, and based on the detection values of the angle sensors 36, 37, 38, the front and side restraint surfaces A1, A3, A2, the front and side restraint areas B1, The control device 40 detects the position of the bucket pin 6a with respect to B2.

As shown in FIG. 3, a pilot oil passage connecting the pilot valve 31a of the right operating lever 9 and the control valve 21 of the first boom portion 4a (operating the control valve 21 of the first boom portion 4a upward). Pilot oil passage), a pilot oil passage connecting the pilot valve 32a of the left operating lever 10 and the control valve 22 of the arm 5 (a pilot oil passage for operating the control valve 22 of the arm 5 to the scraping side), and an operation pedal. Each of the pilot oil passages (the pilot oil passages for operating the control valve 25 of the second boom portion 4b to the left oscillating side) connecting the pilot valve 35a of FIG. -Type pressure control valves 41, 42, 4
3 are provided.

Therefore, the pilot pressure is reduced by the pressure control valves 41, 42 and 43 (the maximum pressure is the value set by the right and left operating levers 9 and 10 and the operating pedal 39), and the right and left operating levers are reduced. 9, 10, regardless of the operation position of the operation pedal 39, the control valve 21 of the first boom portion 4a
Of the control valve 22 of the arm 5, the opening of the control valve 25 of the second boom portion 4b on the left swing side can be arbitrarily changed. By setting the pilot pressure to zero by the pressure control valves 41, 42, 43, the hydraulic cylinder 11, the arm 5 and the arm 5 of the first boom portion 4a can be operated regardless of the operation positions of the right and left operation levers 9, 10 and the operation pedal 39. The hydraulic cylinder 12 of the second boom portion 4b can be stopped.

When the bucket pin 6a is to be operated toward the operation section 15 beyond the front restraint surfaces A1 and A3, the operation is prevented from being restrained. Next, this restraint will be described with reference to FIGS. 7 will be described. Control device 4
At 0, the vertical angle of the first boom portion 4a based on the detection values of the angle sensors 36, 37, 38, and the second boom portion 4b
The position of the bucket pin 6a is always detected from the left-right angle of the arm, the front-rear angle of the arm 5, and the respective lengths of the first boom portion 4a, the second boom portion 4b, and the arm 5 (step S1).

Thus, when the bucket pin 6a enters the front restraint area B1 shown in FIGS. 4 and 5 (step S2), the right operation lever 9 is operated backward to operate the first boom portion 4 (step S2).
a (step S3), the bucket pin 6
a approaches the second front restraint surface A3. In this state, the pilot pressure of the pilot valve 31a is reduced by the pressure control valve 41 shown in FIG.
a (the extension speed of the hydraulic cylinder 11) is decelerated, and the bucket pin 6a is moved to the second front restraint surface A.
As the vehicle approaches 3, the ascending speed of the first boom portion 4 a (the extension speed of the hydraulic cylinder 11) is reduced more (step S <b> 7). Bucket pin 6a is on the second front restraint surface A
The case where the number has reached 3 (step S4) will be described later.

Conversely, when the right operating lever 9 is operated forward to lower the first boom portion 4a (step S3), the bucket pin 6a is separated from the second front restraint surface A3, so that the bucket pin 6a is moved. Even if it is located in the second front restraint surface A3 and the front restraint area B1, the first boom portion 4a is lowered at a speed corresponding to the previous operation position of the right operation lever 9 regardless of this (step). S8) (As shown in FIG. 3, the pressure control valve 41 is not provided in the pilot oil passage of the pilot valve 31b of the right operation lever 9).

When the bucket pin 6a has entered the front restraint area B1 (step S2), the left operating lever 1
When the arm 5 is squeezed after the operation of 0 (step S9), the bucket pin 6a is brought into a state of approaching the second front restraint surface A3. In this state, the pilot pressure of the pilot valve 32 a is reduced by the pressure control valve 42 shown in FIG. 3, and the scraping speed of the arm 5 (the extension speed of the hydraulic cylinder 12) regardless of the operation position of the rear operation of the left operation lever 10. ) Is decelerated, and the bucket pin 6a
As the vehicle approaches the second front restraint surface A3, the speed at which the arm 5 is squeezed (the speed at which the hydraulic cylinder 12 extends) is increased (step S12). Bucket pin 6a is second
When the front control surface A3 is reached (step S10), the pilot pressure of the pilot valve 32a is set to zero by the pressure control valve 42 shown in FIG. Is operated to the neutral position, and the arm 5 (hydraulic cylinder 12) stops (step S1).
1).

Conversely, when the left operating lever 10 is operated forward and the arm 5 is operated to the earth discharging side (step S9), the bucket pin 6a is separated from the second front restraint surface A3, so that the bucket pin 6a Is located in the second front restraint plane A3 and the front restraint area B1, regardless of this, the arm 5 is operated to the earth discharging side at a speed corresponding to the operation position of the front operation of the left operation lever 10 ( Step S13) (As shown in FIG. 3, the pressure control valve 42 is not provided in the pilot oil passage of the pilot valve 32b of the left operating lever 10).

Next, when the bucket pin 6a reaches the second front restraint surface A3 by the raising operation of the first boom portion 4a (steps S3 and S4), the bucket pin 6a is moved by the scraping operation of the arm 5 to the second position. The case where the front restraint surface A3 has been reached (steps S10 and S11) will be described. FIG.
As shown in the figure, an electromagnetically operated switching valve 44 is provided in a pilot oil passage between the pressure control valve 41 (the pilot valve 31a of the right operation lever 9) and the control valve 21. The switching valve 44 has a first position 44a and a second position 44b. In the first position 44a, the pilot pressure of the pilot valve 31a is supplied only to the control valve 21, and the second position 44
b, the pilot pressure of the pilot valve 31a is changed to the left operating lever 1 via the control valve 21 and the pilot oil passage 45.
0 and is supplied to a pilot oil passage between the pilot valve 32b and the control valve 22.
It has been operated to the position 44a.

For example, when the bucket pin 6a reaches the second front restraint surface A3 by the raising operation of the first boom portion 4a (steps S3 and S4), the bucket pin 6a is moved to the second front by the scraping operation of the arm 5. When the vehicle reaches the restraint surface A3 (steps S10 and S11), when the right operation lever 9 is operated backward to perform the raising operation of the first boom portion 4a,
The switching valve 44 shown in FIG.
Simultaneously with the operation at 4b, the pressure control valve 41 slightly increases the pilot pressure from zero.

Accordingly, the pilot pressure of the pilot valve 31a of the right operating lever 9 is supplied to the control valve 21 (upward side) of the first boom portion 4a, and at the same time, the control valve 22 of the arm 5 (upstream side). ), The first boom portion 4a is raised at the lowest speed (the hydraulic cylinder 1).
1 is expanded at the lowest speed) (step S
5) The arm 5 is slowly moved to the discharging side (the hydraulic cylinder 12
Is slowly contracted) (step S6).

When the above operation is performed, as shown in FIG. 4, the first boom portion 4a is raised, and at the same time, the angle D between the second boom portion 4a and the arm 5 is gradually increased. And the bucket pin 6a is
The bucket pin 6a rises along the front restraint surface A3 (while detecting the position of the bucket pin 6a based on the detection values of the angle sensors 36, 37, 38, etc., the bucket pin 6a is moved to the second front restraint surface A3). Pressure control valve 4 so that it is always
1 controls the pilot pressure). Simultaneously, when the right operation lever 9 is operated leftward to rake the bucket 6, the bucket 6 can be maintained horizontal.

As described above, in the case of normal control, the second control
The intrusion of the bucket 6 into the driving unit side is to be prevented by the front restraint surface A3. However, when the driving unit side is to be entered by the driver's intention, a changeover switch provided in the driving unit, etc. The check mode can be changed by the check mode switching means 46 utilizing the. As a result, when the bucket 6 enters the driving section, the first front check surface A1
Is reached, the following control is performed (step S14). That is, when the right operation lever 9 is operated later (step S15), the bucket 6 is moved to the earth discharging side by the arm 5 (step S16). Next, when the bucket pin 6a reaches the second restraint surface A3, the first boom portion 4a is to be lifted (step S1).
8). When the right operation lever 9 is operated forward (step S1)
5) As described above, the first arm portion 4a descends at a speed corresponding to the operation position (step S19).
When the bucket 6 is in the region between the first front restraint surface A1 and the second front restraint surface A3, the control mode is the same as that in the case where the bucket 6 is in the front restraint region B1.

When the bucket pin 6a is operated to the operation section 15 side beyond the lateral restraint surface A2, the operation is prevented from being restrained, and the restraint will be described below. In the control device 40, the angle sensor 3
6, 37, 38, the vertical angle of the first boom portion 4a, the horizontal angle of the second boom portion 4b, the front-back angle of the arm 5, the first boom portion 4a, and the second boom portion 4b.
The position of the bucket pin 6a is always detected based on the length of the arm 5 and the arm 5.

When the operation pedal 39 is depressed to the left and the second boom portion 4b is swung to the left while the bucket pin 6a has entered the lateral restraint area B2, the bucket pin 6a approaches the lateral restraint surface A2. The state is reached (steps S20 to S22). In this state, the pilot pressure of the pilot valve 35a is reduced by the pressure control valve 43 shown in FIG. 3, and the left swing speed of the second boom portion 4a (regardless of the operation position of the left pedal operation of the operation pedal 39) ( The extension speed of the hydraulic cylinder 7) is reduced.
As the bucket pin 6a approaches the lateral restraint surface A2, the second
The left swing speed (extension speed of the hydraulic cylinder 7) of the boom portion 4a is greatly reduced (step S24). When the bucket pin 6a reaches the lateral restraint surface A2, the pilot pressure of the pilot valve 35a is set to zero by the pressure control valve 43 shown in FIG. 3, and the control valve 25 is operated regardless of the operation position of the left pedal operation of the operation pedal 39. Is moved to the neutral position and the second
The boom portion 4b (the hydraulic cylinder 7) stops (step S23).

Conversely, when the operation pedal 39 is depressed to the right and the second boom portion 4b is pivoted to the right, the bucket pin 6
a is separated from the lateral restraint surface A2, so that even if the bucket pin 6a is located in the lateral restraint surface A2 and the lateral restraint area B2, the bucket pin 6a corresponds to the operation position of the right depressing operation of the operation pedal 39 regardless of this. The second boom portion 4b is swung to the right at the speed at which the pressure control valve 4b is connected to the pilot oil passage of the pilot valve 35b of the operation pedal 39 as shown in FIG.
3 is not provided) (step S25).
When an operation other than the swing operation of the second boom portion 4b is performed in the lateral restraint area B2, the vertical movement operation of the first boom portion 4a is performed at an operation speed corresponding to each operation position.
Then, the swing operation of the arm 5 is performed (step S26).
To S29).

In the state where the bucket pin 6a has entered the lateral restraint area B2, the bucket pin 6a can be moved regardless of whether the first boom portion 4a is raised or lowered or the arm 5 is moved to the scraping side or the earth discharging side. Does not approach the lateral restraint surface A2, so that the bucket pin 6a is
2, the operation of raising and lowering the first boom portion 4a and the operation of the arm 5 on the scraping side and the earth discharging side can be performed freely.

[Another Embodiment of the Invention] As described above, the restraint mode switching means 46 is provided, but this switching means 46 may not be provided. In the embodiment of the invention described above, FIG.
As shown in FIG. 5 and FIG. 5, the front and lateral restraint surfaces A1 and A2 are set based on the position of the bucket pin 6a, but an angle sensor (not shown) is also provided at the position of the bucket pin 6a. The front and side restraint surfaces A1 and A2 may be set for the position of the front end of No. 6. In this case, the trajectories C1 and C2 shown in FIG. 5 are the front and lateral restraint surfaces of the present invention.

The operating positions of the right and left operating levers 9 and 10 and the operating pedal 39 are electrically detected by a potentiometer (not shown), and a pilot valve (not shown) of the electromagnetic proportional pressure reducing valve type is operated. The type of operation of the pilot-type control valves 21 to 25 and the operation positions of the right and left operation levers 9 and 10 and the operation pedal 39 are electrically detected by a potentiometer (not shown), and electromagnetically detected based on the detected values. The present invention is also applicable to a type in which a control valve (not shown) of a proportional pressure reducing valve type is operated. Further, the present invention can be applied to a backhoe in which the driving unit 15 is arranged on the right side of the swivel base 2 and the boom 4 (first boom portion 4a) of the backhoe device 3 is arranged on the left side of the swivel base 2.

[Brief description of the drawings]

FIG. 1 is an overall side view of a backhoe.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic cylinder, a control valve, and the like of the backhoe device.

FIG. 3 is a hydraulic circuit diagram showing right and left operation levers, operation pedals, pilot valves, pilot oil passages, and the like.

FIG. 4 is a side view showing a front restraint surface and a front restraint area.

FIG. 5 is a plan view showing front and side restraint surfaces and front and side restraint areas.

FIG. 6 is a flowchart showing control in a front restraint surface and a front restraint area.

FIG. 7 is a flowchart showing control when a boom raising command is issued on the first front braking surface.

FIG. 8 is a flowchart showing control in a lateral restraint region and the like.

[Explanation of symbols]

 5 Arm 6 Bucket 15 Operating Unit 16, 17 External Frame 36, 37, 38 Position Sensor 46 Restriction Mode Switching Means A1 First Restriction Surface A3 Second Retraction Surface

Claims (2)

[Claims] 1. A position sensor for detecting the position of a bucket, and a control means for controlling the operation of the bucket based on the detection of the position sensor is provided, and is separated outward by a predetermined distance from an external frame covering the driving unit. In the space position, a first restraining surface that can prevent the bucket from contacting the outer frame is assumed, and the bucket moves to the scraping side further outward than the first restraining surface and approaches the driving unit. Assuming a second check surface to be blocked, when a control unit issues an ascending command on the first check surface, the bucket starts moving upward after moving once to the earth discharging side. (2) A backhoe configured to start a lifting operation when a lifting command is issued on the restraint surface and outside the restraining surface. 2. A traction mode switching means capable of switching to a state in which a bucket is allowed to move to a rake side beyond the second traction surface in accordance with a traction command to the arm. The described backhoe.