JPH06146331A - Backhoe - Google Patents

Abstract

(57) [Summary] [Purpose] A check surface is set in a space that is a predetermined distance away from the driving section, and when the bucket reaches the check surface, the backhoe device is automatically stopped, and the bucket and the driving section are separated. In the backhoe configured to avoid contact, when the bucket reaches the check surface by operating only the arm to the scraping side, the boom cannot be lifted unless the arm is reversely operated to the front side. To avoid. [Configuration] A first check surface A1 that is a predetermined distance away from an operating portion of the swivel base 2 and a second check surface A2 that is further away from the front are set in space, and the bucket 6 is set to a second check surface A2.
When the bucket 6 reaches the first restraint surface A1, the boom 5 is stopped. Further, the stop operation of the arm 5 on the second check surface A2 is released so that the bucket 6 can be operated up to the first check surface A1 by the arm 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backhoe for avoiding contact between an outer frame covering the outermost part of a driving part and a bucket.

[0002]

2. Description of the Related Art In a backhoe, an example of a structure for avoiding contact between an outer frame that covers the outermost part of a driving part and a bucket is disclosed in Japanese Patent Application Laid-Open No. 2-256722. In this structure, the check surface (the second set position in FIG. 3 of the publication) which is separated by a predetermined distance from the outer frame (3 in FIG. 3 of the publication) covering the outermost part of the driving section. Is set in the space and a position sensor for detecting the position of the bucket (8 in FIG. 3 of the above publication) of the backhoe is provided. Then, when the bucket tries to enter the operation unit side over the restraint surface based on the detection of the position sensor, the restraint means for forcibly returning the control valve of the hydraulic cylinder for the backhoe device to the neutral position and stopping the backhoe device. Is equipped with. With the above configuration, when the operator of the driving section is operating the backhoe device, even if the operation accidentally brings the bucket close to the driving section to a close distance and causes the bucket to collide with the external frame, When the check surface outside the frame is reached, the backhoe device automatically stops and contact is avoided.

[0003]

In the structure described above, as shown in FIG. 3 of the publication, a boom (
When only the arm (9 in FIG. 3 of the above-mentioned publication) is scraped into the driving part with 10) in the figure relatively lowered and stopped, the bucket reaches the check surface and the arm stops. Will be operated. If the boom is lowered in this way, the tip of the boom will be far away from the swivel base, and if the boom is swung in this state, the tip of the boom may contact the wall of the building. It is necessary to raise the boom sufficiently in advance.

However, when the boom is raised from a relatively lowered state as shown in FIG. 3 of the above publication, the boom rises while drawing an arc locus around the connecting point of the swivel base, so that the arm Even if the bucket is stopped, the bucket will approach the driving section. In this case, if the bucket is already located on the restraint surface as described above, the bucket will enter the restraint surface even if the boom is raised, and the boom cannot be raised. Therefore, in order to raise the boom in such a state, the boom cannot be raised until the arm is once moved away from the restraint surface, and there is room for improvement in terms of operability. According to the present invention, in the backhoe having the above-mentioned restraint surface set in the space, the boom cannot be lifted unless the arm is operated to the scraping side and then to the front side again. The purpose is to prevent the condition.

[0005]

A feature of the present invention is that the backhoe as described above is configured as follows. That is, the first check surface that is separated from the external frame that covers the outermost portion of the operating part provided on the swivel base forward by a predetermined distance, and the second check surface that is further separated from the first check surface in front of the space. Setting means, a position sensor for detecting the position of the bucket of the backhoe device, and based on the detection of the position sensor, when the bucket tries to enter the operation unit side beyond the second check surface, the arm for driving the backhoe device is driven. When the bucket tries to enter the operation unit side beyond the first restraint surface based on the detection of the arm restraint means for restraining restraint of the hydraulic cylinder to the scraping side, and the position sensor, the boom driving in the backhoe device is suppressed. Boom restraint means for stopping the hydraulic cylinder to prevent it from being restrained, and release means capable of stopping the restraint operation of the arm restraint means.

[0006]

With the construction of the present invention, as shown in FIG. 3, for example, with the bucket 6 positioned in front of the swivel base 2 and the boom 4 relatively lowered, the arm 5 is swept to the swivel side (the swivel base). 2 side), the bucket 6 first reaches the second check surface A2 to move the arm 5 as shown by the solid line in FIG.
The hydraulic cylinder for use stops and the arm 5 cannot be operated to the scraping side beyond the second restraint surface A2 (corresponding to arm restraint means). In this state, the bucket 6 has not yet reached the first check surface A1, so that the hydraulic cylinder of the boom 4 can be operated. Therefore, it is not necessary to operate the arm 5 forward (away from the swivel base 2) when the arm 5 is stopped at the position shown by the solid line in FIG.
It is sufficient to raise the boom 4 as it is from the state shown by the solid line in FIG. When the boom 4 is lifted in this way, the bucket 6 approaches the side of the first check surface A1 accordingly. When the bucket 6 reaches the first check surface A1, the hydraulic cylinder for the boom 4 stops. Then, the boom 4 can no longer be raised (corresponding to boom restraint means). If the boom 4 can be lifted as described above, the tip of the boom 4 approaches the swivel base 2. Therefore, even if the boom 4 is swung in this state, the tip of the boom 4 does not come into contact with a building wall or the like.

As shown by the solid line in FIG. 3, when the arm 5 is operated to the scraping side and the bucket 6 reaches the second check surface A2, the check operation of the arm check means is stopped. As a result, when the bucket 6 reaches the second check surface A2 and the arm 5 is stopped as shown by the solid line in FIG. 3, the arm 5 is moved over the second check surface A2 as shown by the chain double-dashed line. Further, it can be operated to the scraping side, and the bucket 6 can be brought closer to the swivel base 2. As a result, when the boom 4 cannot be moved up due to the height limitation such as in a building and the excavation is performed only by operating the arm 5 and the bucket 6, the operation range of the arm 5 can be set wide. . Further, when carrying this backhoe by a truck or the like, there is a height limit when carrying it on the road. Therefore, with the boom 4 relatively lowered, the arm 5 is operated sufficiently to the scraping side, and the backhoe is tracked. It can be easily placed on the internet.

[0008]

As described above, in the backhoe in which the restraining surface is set in the space as described above, the boom can be lifted as it is without operating the arm to the scraping side and then the arm again to the front side. It was possible to smoothly shift to the turning state of the swivel by raising the boom, and it was possible to improve the operability of the backhoe. Further, even when the boom is relatively lowered, it is possible to switch to a state in which the arm can be sufficiently operated to the scraping side, so that it is possible to suppress deterioration in workability when performing work only with the arm and the bucket. The backhoe can be easily transported by truck, etc.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. (1) FIG. 7 shows the entire side surface of the backhoe, in which a rubber crawler type traveling device 1 supports a dozer 20 and a swivel base 2 above the dozer 20, and a backhoe device 3 is provided in front of the swivel base 2. There is. The backhoe device 3 is provided with a boom 4 which is rocked up and down by a hydraulic cylinder 11, an arm 5 which is rocked back and forth by a hydraulic cylinder 12, and a bucket 6 which is scraped and rocked by a hydraulic cylinder 13. Is configured. A hydraulic motor 14 is provided to drive the swivel base 2.

The boom 4 in the backhoe device 3 is shown in FIG.
As shown in FIG.
a, a second boom portion 4b that is swingably connected around an axis P1 at the front end of the first boom portion 4a, and the second boom portion 4b.
The support bracket 4c is swingably connected around the axis P2 at the front end of the boom portion 4b, and the arm 5 is connected to the support bracket 4c. The linkage links 8 are laid across the first boom portion 4a and the support bracket 4c to form a parallel four-link structure. By swinging the second boom portion 4b by the hydraulic cylinder 7, the arms 5 and The bucket 6 is configured so that it can be moved left and right in parallel.

As shown in FIG. 6, a control valve 21 for the hydraulic cylinder 11 of the first boom portion 4a of the boom 4,
Hydraulic cylinder 7 of second boom portion 4b of boom 4
A control valve 25 for the hydraulic cylinder 12 of the arm 5, a control valve 23 for the hydraulic cylinder 13 of the bucket 6, and a control valve 24 for the hydraulic motor 14 of the swivel base 2. The control valves 21 to 25 are of a three-position switching type and a pilot operation type, and the flow rate can be controlled by adjusting the opening degree based on the pilot pressure. Then, for each of the control valves 21 to 25, a pilot valve 3 of the electromagnetic proportional pressure reducing valve type that generates a pilot pressure for operating the opening degree
1a, 31b, 32a, 32b, 33a, 33b, 34
a, 34b, 35a, 35b are provided.

As shown in FIGS. 5, 6 and 7, the swivel base 2 is provided with a right operation lever 9 and a left operation lever 10.
The right and left operation levers 9 and 10 can be operated in the front-rear direction and the left-right direction, and are provided with a potentiometer 15 that detects an operation position of the right operation lever 9 in the front-rear direction and a potentiometer 16 that detects an operation position in the left-right direction. A potentiometer 17 that detects an operation position in the front-rear direction of the operation lever 10 and a potentiometer 18 that detects an operation position in the left-right direction are provided. Then, operation signals from the potentiometers 15 to 18 are input to the control device 19. An operation pedal 26 is provided at the lower front portion of the swivel base 2, and an operation signal from the operation pedal 26 is input to the control device 19.

With the above construction, when the right operation lever 9 is operated forward or backward, the pilot valves 31a, 3 are accordingly operated.
1b generates pilot pressure, the control valve 21 is operated to the down side or the up side of the boom 4, and when it is operated to the right or left, the pilot valves 33a and 33b generate pilot pressure based on this, and the control valve 23 moves to the bucket. 6 is operated to the soil discharge side or the scraping side. Further, when the left operation lever 10 is operated forward or backward, the pilot valves 32a and 32b generate pilot pressure based on this, and the control valve 22 is operated to the raising side or the scraping side of the arm 5 and to the right or left. Based on this, the pilot valves 34a and 34b generate pilot pressure, and the control valve 24 is operated to the right turning side or the left turning side. When the operation pedal 26 is stepped right or left, the pilot valves 35a and 35b generate pilot pressure based on this, and the control valve 25 is operated to the right or left swing side of the second boom portion 4b.

In the above operation, the potentiometers 15 to 18 for the right and left operation levers 9 and 10 detect not only the operation direction of the right and left operation levers 9 and 10 but also the operation amount from the neutral position thereof. There is. As a result, as the operation amount of the right and left operation levers 9 and 10 increases, the pilot pressure of the pilot valves 31a to 34b increases and the control valve 21 increases.
.About.24 are operated to the higher flow rate side. That is, the larger the right and left operating levers 9 and 10 are operated, the more hydraulic cylinder 11
13 to 13 and the hydraulic motor 14 are configured to operate at high speed.

(2) As shown in FIGS. 5 and 7, the swivel base 2
In FIG. 1, the backhoe device 3 is arranged on the right side, and the driver's seat 28, the driver unit 27 including the right and left operating levers 9 and 10 are arranged on the left side. A vertical partition plate 29 (corresponding to an external frame that covers the outermost portion of the driving unit 27) with a window for partitioning the backhoe device 3 and the driving unit 27 is provided in the left and right center of the swivel base 2. A semicircular upper partition plate 30 (corresponding to an outer frame that covers the outermost part of the operation unit 27) along the outside of the swivel base 2 is fixed to the upper end of the partition plate 29.

As shown in FIGS. 3 and 5, in the range above a predetermined position D at a predetermined height from the ground G, the front first check restraint which is separated from the vertical partition plate 29 by a predetermined distance in front (outward). The surface A1, the front second check surface A2 that is further away from the front first check surface A1, and the lateral check that is separated from the side surface of the vertical partition plate 29 on the backhoe device 3 side to the right (outward) by a predetermined distance. The surface C is set in the control device 19 (corresponding to setting means). In this case, when the boom 6 is moved up while the bucket 6 is horizontally positioned at the position shown by the solid line in FIG. 3, the trajectory drawn by the tip 6a of the bucket 6 is the front second check surface A2. Further, the front first and second front restraint surfaces A1 and A2, and the surface which is separated from the lateral restraint surface C by a predetermined distance to the front or right are set, and the surface of this space and the front first and second front restraint surfaces are set. The areas between A1, A2 and the lateral restraint surface C are set in the control device 19 as a front first restraint area B1, a front second restraint area B2 and a lateral restraint area B3.

When excavating the ground G by the backhoe device 3, the mechanical operating limit of the backhoe device 3 itself, that is, how close the backhoe device 3 can excavate to the traveling device 1 side, is obtained in advance. There is. Then, it is calculated which trajectory the tip 6a of the bucket 6 passes through when the operation limit is reached, and a trajectory having a margin (outer side) from the trajectory of the tip 6a of the bucket 6 corresponding to the operation limit is calculated. As a boundary surface E, as shown in FIG.
In the lower range, the boundary surface E is set in the control device 19. The boundary surface E is set so as to smoothly connect to the front first check surface A1. The front first and front second check surfaces A1 and A2, the horizontal check surface C, the front first and second check areas B1 and B2, the horizontal check area B3, and the boundary surface E as described above.
Is set for the swivel base 2, and moves with the swivel base 2 as the swivel base 2 turns.

(3) Next, the control of the backhoe device 3 with respect to the front first and second check surfaces A1 and A2 and the front first and second check areas B1 and B2 will be described. Figure 7
And as shown in FIG. 6, the boom 4 (first boom portion 4
a) a potentiometer 36 (corresponding to a position sensor) that detects the vertical angle, a potentiometer 37 (corresponding to a position sensor) that detects the horizontal angle of the second boom portion 4b,
Potentiometer 38 for detecting the front-back angle of the arm 5
(Corresponding to a position sensor), and a potentiometer 39 (corresponding to a position sensor) for detecting the longitudinal angle of the bucket 6.
Is provided, and each of these potentiometers 36 to 39 is provided.
The detection signal from is input to the control device 19.

In the controller 19, as shown in FIG. 1, the vertical angle of the first boom portion 4a, the horizontal angle of the second boom portion 4b, the longitudinal angle of the arm 5 and the bucket 6 based on the detection signals from the potentiometers 36 to 39. And the first
The positions of the tip 6a of the bucket 6 and the position of the bottom 6b of the bucket 6 are constantly calculated from the lengths of the boom portion 4a, the second boom portion 4b, the arm 5 and the bucket 6 (steps S1 and S2). And potentiometer 3
The moving direction and moving speed of the tip 6a and the bottom 6b of the bucket 6 are calculated by differentiating the detection values of 6 to 39.

As a result, as shown in FIG. 3, the bucket 6
When the front end 6a of the bucket 6 is closer to the swivel base 2 than the bottom portion 6b in the state where the front end 6a of the bucket 6 is located in front of the swivel base 2 (step S3), when the front end 6a of the bucket 6 enters the front second restraint region B2. (Step S4), the pilot valves 32a and 32b are operated and the operating speed of the hydraulic cylinder 12 of the arm 5 is decelerated regardless of the operation of the left operation lever 10 (step S5). In this case, bucket 6
As the leading end 6a of the above enters the front second check area B2 and approaches the front second check surface A2, the deceleration operation is greatly performed. On the contrary, when the arm 5 is operated in the direction in which the tip 6a of the bucket 6 moves away from the second front restraining surface A2, the hydraulic cylinder 12 of the arm 5 moves in the front second restraining region B2 contrary to the deceleration described above. The operating speed of is increased, and when it goes out from the second front restraint region B2, it is returned to the normal speed.

When the tip 6a of the bucket 6 reaches the front second check surface A2 and is about to be operated by the operation unit 27 side beyond the second front check surface A2 (step S6), The pilot pressures of the pilot valves 32a and 32b disappear, and the control valve 22 causes the hydraulic cylinder 12 of the arm 5 to stop (step S7) (corresponding to arm restraining means). In this state, the operation of the bucket 6 by the hydraulic cylinder 13 and the operation of the first boom portion 4a by the hydraulic cylinder 11 can be performed. Therefore, as in the above-described state shown by the solid line in FIG.
When the boom portion 4a is moved up, the tip 6a of the bucket 6 is moved up along the front second check surface A2.

As shown by the solid line in FIG. 3, the tip 6a of the bucket 6 is moved to the front second position by operating the arm 5 toward the driving section 27.
In the state where the check surface A2 is reached, the first boom portion 4a
If the hydraulic cylinder 11 is stopped (step S
8) Then, the timer starts counting the set time (step S17). Then, when the hydraulic cylinder 11 of the first boom portion 4a is stopped until the counting of the set time is completed (steps S18 and S19), the stop operation of the hydraulic cylinder 12 of the arm 5 is released (step S).
20) (corresponding to releasing means). As a result, from the state where the tip 6a of the bucket 6 reaches the front second check surface A2 as shown by the solid line in FIG. 3 and the arm 5 is stopped, as shown by the chain double-dashed line, the hydraulic cylinder 12 causes the arm 5 ( The bucket 6) can be operated toward the operation unit 27 side beyond the front second check surface A2.

As described above, when the tip end 6a of the bucket 6 enters the front first restraint region B1 by the raising operation of the first boom portion 4a or the operation of the arm 5 toward the operating portion 27 side (step S9), FIG. As shown in FIG.
31b, 32a, 32b, 35a, 35b are operated so that the first and second boom portions 4a, 4b and the hydraulic cylinders 11, 12 of the arm 5 are irrespective of the operation of the right and left operation levers 9, 10, the operation pedal 26. , 7 is decelerated (step S10). In this case, as the tip 6a of the bucket 6 enters the front first check area B1 and approaches the front first check surface A1, the deceleration operation is greatly performed. On the contrary, when the first boom portion 4a is operated to descend, when the second boom portion 4b is operated to the left and right center side of the swing range, and when the arm 5 is operated to the front side (the above operations are (The tip 6a of the bucket 6 is in the direction away from the front first check surface A1), the operating speed of the hydraulic cylinders 11, 12, 7 is increased in the front first check area B1 contrary to the deceleration described above. Then, when the vehicle goes out of the front first check area B1, the operation is returned to the normal speed.

When the tip 6a of the bucket 6 reaches the front first check surface A1 and is about to go over the front first check surface A1 to be operated by the operation unit 27 side (step S11), Pilot valves 31a, 31b, 32
a, 32b, 35a, 35b pilot pressure disappears,
The control valves 21, 22, 25 stop the first and second boom portions 4a, 4b and the hydraulic cylinders 11, 12, 7 of the arm 5 (step S12) (corresponding to boom restraining means).

As shown in FIG. 4, when the tip end 6a of the bucket 6 is located on the front first check surface A1, if the attitude of the bucket 6 is located within the setting range F with the horizontal H interposed ( In step S13), the bucket 6 can be vertically swung by the hydraulic cylinder 13 within the set range F (step S14). When the bucket 6 is in the upward posture exceeding the setting range F and the tip 6a thereof is positioned on the front first check surface A1, when the bucket 6 is swung downward, the tip 6a of the bucket 6 moves forward. 1 Check surface A
In this case, the bucket 6 can only be swung upward from the current state because it largely exceeds 1 and enters the operation unit 27 side (step S15). On the contrary, when the bucket 6 is in the downward posture exceeding the setting range F and the tip 6a thereof is located on the front first check surface A1, when the bucket 6 is rocked upward, the tip 6a of the bucket 6 moves forward. Since it greatly enters the operation unit 27 side beyond the first restraint surface A1, in such a case, the bucket 6 can only be swung downward from the current state (step S16).

As shown in FIG. 3, the bottom portion 6 of the bucket 6 is in a state in which the bucket 6 is located in front of the swivel base 2.
When b is closer to the swivel base 2 than the tip 6a (step S
3), as in the case of the tip 6a as shown in FIGS. 1 and 2, the hydraulic cylinder of the arm 5 is decelerated and stopped based on the bottom 6b of the bucket 6 (step S).
5, S7), and the first and second boom portions 4a, 4
b, deceleration operation and stop operation of the hydraulic cylinders 11, 12, 7 of the arm 5 (steps S10, S12) are performed.
When the bottom portion 6b of the bucket 6 reaches the front first check surface A1, the bottom portion 6b is positioned on the front first check surface A1 in an upward posture in which the bucket 6 exceeds the setting range F. When the bucket 6 is rocked downward, the bucket 6
In this case, the bucket 6 has a large amount of force, since a exceeds the front first restraining surface A1 and enters the driving section 27 side.
Can only be swung upwards from the current state.

(4) Next, the lateral restraint surface C and the lateral restraint area B
The control of the backhoe device 3 with respect to No. 3 will be described.
In the control device 19, similarly to the above, 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 and the bucket 6, and the first boom portion in response to the signals from the potentiometers 36 to 39. The position of the left lateral side surface of the bucket 6 is constantly calculated from the lengths of the bucket 4a, the second boom portion 4b, the arm 5, and the bucket 6.
Then, the moving direction and moving speed of the left lateral surface of the bucket 6 are calculated by differentiating the detection values of the potentiometers 36 to 39.

When the bucket 6 is located on the right side of the operating portion 27 as shown by the solid line in FIG. 5, the second boom portion 4b is swung to the operating portion 27 side by the hydraulic cylinder 7 to swing the bucket. When the left lateral surface of 6 enters the lateral restraint area B3, the pilot valves 35a and 35b are operated and the second boom portion 4b is operated regardless of the operation of the operation pedal 26.
The operating speed of the hydraulic cylinder 7 is decelerated. In this case, as the left lateral side surface of the bucket 6 enters the lateral restraint area B3 and approaches the lateral restraint surface C, the deceleration operation is greatly performed.
On the contrary, when the second boom portion 4b is operated in the direction in which the left lateral side surface of the bucket 6 moves away from the lateral restraint surface C, contrary to the deceleration described above, the second boom portion 4b moves in the lateral restraint area B3. The operating speed of the hydraulic cylinder 7 is increased and then returned to the normal speed when the hydraulic cylinder 7 exits the lateral restraint region B3. When the left lateral side surface of the bucket 6 reaches the lateral restraint surface C and is about to be operated toward the operating unit 27 side beyond the lateral restraint surface C, the pilot valves 35a, 3
The pilot pressure of 5b disappears, and the control valve 25 stops the hydraulic cylinder 7 of the second boom portion 4b.

(5) Next, the control of the backhoe device 3 in the region below the predetermined position D will be described. As described above, in the portion above the predetermined position D shown in FIG. 3, the front first and second front restraint regions B1 and B2 and the lateral restraint region B3 are provided.
Is set, but such a thing is not set in the portion below the predetermined position D. Therefore, until the tip 6a of the bucket 6 reaches the boundary surface E, the hydraulic cylinders 11, 12, of the backhoe device 3 are moved at a speed based on the operation of the right and left operation levers 9, 10, and the operation pedal 26.
7 is operated. When the tip 6a of the bucket 6 is about to be operated toward the traveling apparatus 1 beyond the boundary surface E, the pilot valves 31a to 32b, 35a, 3 are used.
The pilot pressure of 5b disappears and the control valves 21, 22, 25
The hydraulic cylinders 11, 12, 7 of the backhoe device 3
Is stopped.

When the tip 6a of the bucket 6 is located on the boundary surface E, the hydraulic cylinder 13 of the bucket 6 can be operated, and the tip 6a of the bucket 6 can be moved on the boundary surface E as well. You can do it. Therefore, when the soil on the ground G near the traveling device 1 is scraped off by the bucket 6, the bucket 6 may be lifted so that the tip 6a of the bucket 6 moves upward on the boundary surface E. is there. In this way, the tip 6a of the bucket 6 smoothly moves from the boundary surface E to the front first check surface A1 and enters the front first check area B1, and the backhoe device 3 decelerates as described above. Is done.

[Other Embodiments] In the above-mentioned embodiment, the operation positions of the right and left operation levers 9 and 10 are set to the potentiometer 15.
18 is a type in which the pilot operated control valves 21 to 25 are electrically detected by the electromagnetic proportional pressure reducing valve type pilot valves 31a to 35b, and the present invention is applied to this type. The present invention may be applied to a backhoe having the following configuration. That is, the operating positions of the right and left operating levers 9 and 10 are adjusted without adjusting the pilot valves 31a to 35b of the electromagnetic proportional pressure reducing valve type described above.
5 to 18 is a type for electrically detecting and operating the control valves 21 to 25 of the electromagnetic proportional pressure reducing valve type based on the detected value.
Also, without equipping the above potentiometers 15-18,
This is a type in which a pilot valve (not shown) is directly mechanically operated by operating the right and left operation levers 9 and 10, and the control valves 21 to 25 are switched and operated by pilot hydraulic oil from the pilot valve.

In the various types of backhoes as described above, when the first boom portion 4a is stopped for the set time as shown in steps S17 to S20 of FIG. 1, the stop operation of the hydraulic cylinder 12 of the arm 5 is performed. Is not released, but a state in which the arm 5 is stopped by the front second check surface A2 and a state in which the arm 5 is not stopped by a changeover switch (not shown) provided in the operating unit 27 Alternatively, it may be configured so that the switching operation can be performed artificially.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a front half flow of control in front first and second check surfaces and front first and second check regions.

FIG. 2 is a diagram showing a flow of the latter half of the control in the front first and second check surfaces and the front first and second check regions.

FIG. 3 is a schematic side view of a backhoe showing front first and second check surfaces and front first and second check regions.

FIG. 4 is a side view in which the tip of the bucket reaches the front first check surface.

FIG. 5 is a schematic plan view of a backhoe showing front first and second control surfaces, front first and second control areas, lateral control surfaces, and lateral control areas.

FIG. 6 shows hydraulic cylinders for the backhoe device, control valves,
Diagram showing the relationship between the pilot valve, right and left operating levers, etc.

FIG. 7: Side view of the entire backhoe

[Explanation of symbols]

 2 Swivel base 3 Backhoe device 4 Boom 5 Arm 6 Bucket 11,12 Hydraulic cylinder 27 Operating part 29,30 External frame 36,37,38,39 Position sensor A1 1st check surface A2 2nd check surface

Claims (1)

[Claims] 1. An operating unit (2) provided on a swivel base (2).
7) A first check surface (A1) that is separated from the outer frames (29) and (30) that covers the outermost side of the outer surface by a predetermined distance, and a second check surface that is further separated from the first check surface (A1). Setting means for setting the check surface (A2) in space and position sensors (36), (37), (38), (39) for detecting the position of the bucket (6) of the backhoe device (3).
And the position sensors (36), (37), (38), (3
When the bucket (6) tries to enter the operation unit (27) side beyond the second check surface (A2) based on the detection of 9), the hydraulic pressure for driving the arm (5) in the backhoe device (3). Arm restraint means for restraining the operation of the cylinder (12) toward the scraping side, and the position sensors (36), (37), (38), (3).
When the bucket (6) tries to enter the operation unit (27) side beyond the first check surface (A1) based on the detection of 9), the hydraulic pressure for driving the boom (4) in the backhoe device (3). A backhoe provided with boom restraining means for stopping the cylinder (11) to prevent it from restraining, and releasing means capable of stopping the restraining operation of the arm restraining means.