JP2744569B2 - Backhoe - Google Patents

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 contacting an outer frame covering an outermost portion of a driving section with a bucket.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Hei 2-256722 discloses an example of a structure of a backhoe that avoids contact between an outer frame covering an outermost portion of a driving unit and a bucket. In this structure, a check surface (a second set position in FIG. 3 of the above-mentioned publication) which is separated by a predetermined distance from an external frame (3 in FIG. 3 of the above-mentioned publication) which covers the outermost part of the driving unit. 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 device is provided. Then, when the bucket attempts to enter the driving section side beyond the check surface based on the detection of the position sensor, the control valve of the hydraulic cylinder for driving the backhoe device is forcibly returned to the neutral position, and the backhoe device is stopped. Means. With the above configuration, when the operator of the driving unit is operating the backhoe device, even if the bucket is erroneously brought close to the driving unit side so as to collide with the external frame, the bucket is not moved to the outside. Upon reaching the restraining surface outside the frame, the backhoe device automatically stops and contact is avoided.

[0003]

In the backhoe, excavation work is performed with the boom (10 in FIG. 3 of the above publication) lowered relatively as shown in FIG. The lifting operation and the scraping operation of the arm (9 in FIG. 3 of the above-mentioned publication) are simultaneously performed, and the backhoe device is folded small and turned to start the next operation. In this case, if the operation of raising the boom and the operation of scraping the arm are performed simultaneously while the boom is relatively lowered and stopped as shown in FIG. When the arm is squeezed before being operated, the bucket may reach the check surface and the arm may be stopped first. In this state, the boom has not yet been raised enough, so the tip of the boom is protruding far ahead of the swivel, and when turning in this state, the tip of the boom contacts the walls of the building, etc. There is a possibility that.

[0004] Therefore, it is only necessary to raise the boom after the arm is stopped. However, the boom rises while drawing an arc trajectory around the connecting point of the swivel base. The bucket comes closer to the driving unit with the rise. In this case, as described above, if the bucket is already positioned on the check surface, the bucket will enter the check surface even if the boom is to be raised. No state. Therefore, in order to raise the boom in such a state, the operation of raising the boom cannot be performed unless the arm is operated once in a direction away from the tether surface, and there is room for improvement in operability. The present invention relates to a backhoe in which the restraining surface is set in space as described above,
It is an object of the present invention to prevent a situation in which, when a boom raising operation and an arm scraping operation are performed simultaneously, the boom raising operation cannot be performed unless the arm is again operated forward.

[0005]

The feature of the present invention resides in the following configuration of the above-mentioned backhoe. That is, [1] first setting means for setting, in space, a first restraint surface spaced a predetermined distance forward from an external frame covering an outermost portion of a driving unit provided on the swivel base, and a position of a bucket of the backhoe device. A first check that stops the backhoe device driving hydraulic cylinder and prevents the first cylinder from stopping when the bucket attempts to enter the driving unit side beyond the first check surface based on the detection of the position sensor and the position sensor. Means and a second further away from the first restraint surface.
Second setting means for setting the check surface on the space; detecting means for detecting that the operation of raising the boom of the backhoe device and the operation of scraping the arm have been performed simultaneously; A second restraint means for stopping the hydraulic cylinder for driving the arm when the bucket reaches the second restraint surface during the simultaneous operation of the arm scraping.

In the configuration of the above [1], the position sensor is a potentiometer for detecting the angle of the boom with respect to the swivel table, and the potentiometer for detecting the angle of the arm with respect to the boom. , The simultaneous operation of raising the boom and scraping the arm is detected.

[0007]

[Action]

[I] With the configuration described in [1] above, for example, as shown in FIG. 4, it is assumed that the raising operation of the boom 4 and the scraping operation of the arm 5 in the backhoe apparatus have started to be performed simultaneously. In this case, generally, as shown by the solid line in FIG.
The hydraulic cylinder for driving the arm 5 is stopped by the action of the second restraint means, and the arm 5 stops at that position. In this state, since the bucket 6 has not yet reached the first restraint surface A1, the raising operation of the boom 4 is continuously performed. Boom 4 like this
When the bucket 6 is moved upward, the bucket 6 approaches the first braking surface A1 side, and when the bucket 6 reaches the first braking surface A1, the hydraulic cylinder for driving the boom 4 is stopped. The boom 4 stops at that position.

If the boom 4 can be lifted as described above, the tip of the boom 4 approaches the swivel 2 and the tip of the boom 4 contacts the wall of the building or the like even when turning in this state. There is no danger. In this case, the operator of the driving unit only needs to perform the raising operation of the boom 4 and the scraping operation of the arm 5 at the same time, and the arm 5 stops first, and then the boom 4 moves up and stops. There is no need to re-operate the arm 5 forward (in a direction away from the swivel 2).

[0009] On the other hand, other than the state in which one of the boom 4, the arm 5, and the bucket 6 of the backhoe apparatus is operated alone, and the state in which the raising operation of the boom 4 and the scraping operation of the arm 5 are performed simultaneously. In normal working conditions,
The second check surface A2 has no relation to the control of the bucket 6,
The boom 4, the arm 5, and the bucket 6 can be normally operated inside and outside the second restraining surface A2. And
When the bucket 6 reaches the first restraining surface A1 as shown by the two-dot chain line, even if the bucket 6 is moved to the operation section side beyond the first restraining surface A1, this operation is performed by the action of the first restraining means. I can't.

In this case, if only the arm 5 is operated alone on the scraping side, as shown by a two-dot chain line in FIG.
By operating the bucket 6 to the driving unit side beyond the check surface A2,
The bucket 6 can approach the swivel 2. As a result, when the excavation is performed only by operating the arm 5 and the bucket 6 because the height of the boom 4 cannot be raised and the excavation is performed only by operating the bucket 5 as in a building or the like, the operation range of the arm 5 is restricted by the second check. There is no narrowing by the surface A2. Also, when transporting this backhoe by truck or the like,
Since there is a height restriction when transporting on a road, the backhoe can be placed on a truck or the like without difficulty by operating the arm 5 sufficiently on the scraping side with the boom 4 relatively lowered.

[II] In the case of the configuration as described in the above item [1], as a position sensor for detecting the position of the bucket 6,
For example, as shown in FIG. 8, a potentiometer 36 for detecting the angle of the boom 4 with respect to the swivel base 2 and a potentiometer 38 for detecting the angle of the arm 5 with respect to the boom 4 are often used. Therefore, by observing the change in the detection values of the potentiometers 36 and 38, it is possible to determine the state in which the boom 4 is being raised and the state in which the arm 5 is being scraped. Thus, the detecting means for detecting a state in which the raising operation of the boom 4 and the scraping of the arm 5 are simultaneously performed and the potentiometers 36 and 38 for detecting the position of the bucket 6 can be shared.

[0012]

According to the first aspect of the present invention, in the backhoe in which the restraining surface is set in a space, even if the arm is operated to the scraping side and the arm is not operated again to the front side, the operation of scraping the arm is performed. The operation of raising the boom can be performed while performing the operation, so that the turning state of the swivel table with the boom raised can be smoothly shifted, and the operability of the backhoe can be improved. Further, even when the boom is relatively lowered, the arm can be sufficiently operated to the scraping side, so that it is possible to suppress a decrease in workability when working only with the arm and the bucket, and to perform a backhoe on a truck or the like. Can be transported without difficulty. Claim 2
With this configuration, the potentiometer for detecting the position of the bucket can also be used as the detecting means for detecting that the simultaneous operation of raising the boom and squeezing the arm has been performed. Since it can be omitted, it is advantageous in terms of reduction of production cost.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (1) FIG. 8 shows the entire side surface of the backhoe. A traveling device 1 of rubber crawler type supports a dozer 20 and a swivel 2 above the dozer 20. A backhoe 3 is provided at the front of the swivel 2. I have. The backhoe device 3 includes a boom 4 that is driven to swing up and down by a hydraulic cylinder 11, an arm 5 that is driven to swing back and forth by a hydraulic cylinder 12, and a bucket 6 that is driven to swing by a hydraulic cylinder 13. It is configured. A hydraulic motor 14 is provided for driving the swivel 2 to turn.

The boom 4 in the backhoe 3 is shown in FIG.
As shown in the figure, the first boom part 4 is driven to swing up and down.
a, a second boom part 4b swingably connected around an axis P1 at a front end of the first boom part 4a, and a second boom part 4b.
A 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 link 4 is erected between the first boom portion 4a and the support bracket 4c to form a parallel quadruple link. The hydraulic cylinder 7 swings the second boom portion 4b, so that the arms 5 and The bucket 6 is configured so as to be able to move in parallel from side to side.

As shown in FIG. 7, the 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 22 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 2. The control valves 21 to 25 are of a three-position switching type and of a pilot operation type, and the flow rate can be controlled by adjusting the opening based on the pilot pressure. An electromagnetic proportional pressure-reducing valve type pilot valve 3 for generating a pilot pressure for opening degree operation is provided to each of the control valves 21 to 25.
1a, 31b, 32a, 32b, 33a, 33b, 34
a, 34b, 35a, and 35b are provided.

As shown in FIGS. 6, 7, and 8, the turntable 2 is provided with a right operation lever 9 and a left operation lever 10.
The right and left operation levers 9 and 10 are freely operable back and forth and left and right, and are provided with a potentiometer 15 for detecting a front and rear operation position of the right operation lever 9 and a potentiometer 16 for detecting a left and right operation position. A potentiometer 17 for detecting the operation position of the operation lever 10 in the front-rear direction and a potentiometer 18 for detecting the operation position in the left-right direction are provided. Operation signals from the potentiometers 15 to 18 are input to the control device 19. An operation pedal 26 is provided at a lower portion on the front side of the swivel base 2, and an operation signal from the operation pedal 26 is input to the control device 19.

With the above configuration, when the right operating lever 9 is operated forward or backward, the pilot valves 31a, 3
1b generates a pilot pressure, the control valve 21 is operated on the lower side or the upper side of the first boom portion 4a, and when the control valve 21 is operated on the right or left side, the pilot valves 33a and 33b generate the pilot pressure based on the operation, and the control valve 23 is operated on the earth discharging side or the scraping side of the bucket 6. When the left operating lever 10 is operated forward or backward, the pilot valve 32
a and 32b generate pilot pressure, and the control valve 22 is operated to raise or scrape the arm 5, and when it is operated to the right or left, the pilot valves 34a and 34b generate pilot pressure based on this, and 24 is operated to the right turning side or the left turning side. When the operation pedal 26 is depressed to the 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, each of the potentiometers 15 to 18 for the right and left operation levers 9 and 10 detects not only the operation direction of the right and left operation levers 9 and 10 but also the operation amount from the neutral position. I have. As a result, as the operation amounts of the right and left operation levers 9 and 10 increase, the pilot pressures of the pilot valves 31a to 34b increase and the control valve 21
-24 are operated to the large flow rate side. In other words, the larger the right and left operation levers 9 and 10 are operated, the more the hydraulic cylinder 11
13 and the hydraulic motor 14 are configured to operate at high speed.

(2) As shown in FIG. 6 and FIG.
, The backhoe device 3 is disposed on the right side, and the driver's seat 28 and the driving unit 27 including the right and left operation levers 9 and 10 are disposed on the left side. A vertical partition plate 29 with a window (corresponding to an outer frame that covers the outermost portion of the driving unit 27) is provided in the center of the swivel 2 at the left and right sides to separate the backhoe device 3 from the driving unit 27. A semicircular upper partition plate 30 (corresponding to an outer frame that covers the outermost portion of the operation unit 27) is fixed to the upper end of the partition plate 29 along the outside of the swivel 2.

As shown in FIG. 4, a front first restraining surface A1 separated from the upper partition plate 30 by a predetermined distance, and separated from the vertical partition plate 29 by a predetermined distance, is set in the control device 19. (Corresponding to the first setting means). In a range above a predetermined position D at a predetermined height from the ground G, the front second restraining surface A2 bulging slightly forward from the front first restraining surface A1.
Are set in the control device 19 (corresponding to a second setting unit). In this case, the bucket 6 is positioned at the position indicated by the solid line in FIG.
Is positioned, the first boom portion 4a
When the (boom 4) swings up and down around the support point 40 with the swivel 2, an arc-shaped trajectory in a side view drawn by the tip of the bucket 6 is defined as the front second restraint surface A2.

As shown in FIG. 6, a lateral restraint surface C is set in the control device 19 at a predetermined distance to the right from the side surface of the vertical partition plate 29 on the side of the backhoe device 3. As shown in FIG. 4, in a range above the predetermined position D, the front first and front second restraint surfaces A1 and A2, and a surface separated from the lateral restraint surface C by a predetermined distance forward or to the right are set, The surface of this space, the first and second front restraint surfaces A1, A2, and the horizontal restraint surface C
Between the front first check area B1 and the front second check area B
2. The lateral restraint area B3 is set in the control device 19. The front first and second front check surfaces A1, A as described above
2. Lateral restraint surface C, front first and second front restraint areas B1, B
2. The lateral restraint area B3 is set for the swivel base 2 and moves together with the swivel base 2 as the swivel base 2 turns.

(3) Next, the front first and second front check surfaces A
1, A2, the control of the backhoe device 3 with respect to the front first and second front restraint areas B1, B2 (states other than the state where the raising operation of the first boom portion 4a and the scraping operation of the arm 5 are performed simultaneously) ). As shown in FIGS. 7 and 8, a potentiometer 36 (corresponding to a position sensor) for detecting the vertical angle of the first boom portion 4a, a potentiometer 37 (corresponding to the position sensor) for detecting the left and right angle of the second boom portion 4b, A potentiometer 38 (corresponding to a position sensor) for detecting the front-rear angle of the arm 5 and a potentiometer 39 (corresponding to the position sensor) for detecting the front-rear angle of the bucket 6 are provided. Detection signals from these potentiometers 36 to 39 are provided. Is input to the control device 19.

In the control device 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 front-back 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 and the bottom of the bucket 6 are constantly calculated based on the lengths of the boom portion 4a, the second boom portion 4b, the arm 5, and the bucket 6 (Steps S1 and S1).
2). Then, by differentiating the detection values of the potentiometers 36 to 39, the moving direction and the moving speed of the tip and bottom of the bucket 6 are calculated (step S3).
S4).

As a result, as shown in FIG.
Is located in front of the swivel base 2 and the tip of the bucket 6 is closer to the swivel base 2 than the bottom (step S5), one of the first and second boom portions 4a and 4b, the arm 5, and the bucket 6 One is being operated, that is, a state other than a state in which the raising operation of the first boom portion 4a and the scraping operation of the arm 5 are performed simultaneously (step S
6). In this case, the front second restraint surface A2 and the front second restraint region B2 of FIG. 4 have no relation to the control of the bucket 6, and the first and second restraint surfaces A2 and B2 are in the first and second restraint regions B2. The second boom portions 4a, 4b, the arm 5, and the bucket 6 can be independently operated as usual, and the control of the bucket 6 is performed on the front first restraint surface A1 and the front first restraint area B1 as described below. It is done.

That is, the first or second boom portion 4a, 4
b, when the tip of the bucket 6 enters the front first restraint region B1 by the sole operation of the arm 5 and the bucket 6 (step S7), the pilot valves 31a to 32b, 35a, and 35b.
Is operated, regardless of the operation of the right and left operation levers 9, 10 and the operation pedal 26, the first and second boom portions 4a, 4a,
The operating speeds of the hydraulic cylinders 11 and 7 of 4b and the hydraulic cylinder 12 of the arm 5 are reduced (Step S8). In this case, as the leading end of the bucket 6 enters the front first restraining area B1 and approaches the front first restraining surface A1, the hydraulic cylinders 11, 7, and 12 are greatly decelerated. Conversely, when the first and second boom portions 4a, 4b and the arm 5 are operated in a direction in which the tip of the bucket 6 moves away from the front first restraint surface A1, the front first restraint is performed contrary to the aforementioned deceleration. In the area B1,
The operating speeds of the hydraulic cylinders 11, 7, 12 are increased, and are returned to the original speed when the hydraulic cylinders 11, 7, and 12 come out of the front first restraint area B1.

The tip of the bucket 6 is positioned at the first position in FIG.
It is assumed that the vehicle has reached the restraint surface A1 (step S9) (see the state of the two-dot chain line in FIG. 4). In this case, as shown in FIG. 3, even if the arm 5 is operated to the scraping side, the first boom part 4a is operated to the rising side, and the second boom part 4b is moved to the left swing side (the driving unit 27). Side), the tip of the bucket 6 enters the driving unit 27 side beyond the front first restraint surface A1. As a result, the front end of the bucket 6 is
1, the left operating lever 10 moves the arm 5 to the scraping side, the right operating lever 9 raises the first boom portion 4a, and the operating pedal 26 moves the second boom portion 4b to the left swinging side. The pilot valves 31a-32b,
The pilot pressure of 35a, 35b disappears, and the control valve 21,
The stop operation of the hydraulic cylinders 11, 7, 12 is performed by the steps 22, 25 (steps S10, S11, S12) (first step).
Equivalent to check means). Conversely, with the tip of the bucket 6 reaching the front first restraining surface A1, the raising operation of the arm 5, the lowering operation of the first boom portion 4a, and the right swing operation of the second boom portion 4b are performed by the bucket 6 These operations can be performed without any trouble because the tip is in the direction away from the front first restraint surface A1.

The operation of the bucket 6 by the hydraulic cylinder 13 in a state where the tip of the bucket 6 reaches the front first braking surface A1 is enabled under the following conditions. That is, as shown in FIG.
In a state where the tip of the bucket 6 is located on the front first restraining surface A1, if the posture of the bucket 6 is located within the set range F across the posture H orthogonal to the front first restraining surface A1 (step S13). , Within this set range F, the hydraulic cylinder 13
The vertical swing operation of the bucket 6 can be performed (step S14). Then, in a state where the bucket 6 is in the upward posture beyond the set range F and the tip thereof is located on the front first restraint surface A1, when the bucket 6 is swung downward, the tip of the bucket 6 becomes the first first restraint. In such a case, the bucket 6 may enter the driving unit 27 side beyond the surface A1.
Can only be rocked upward from the current state (step S15). Conversely, in a state where the bucket 6 is in a downward position beyond the set range F and the tip thereof is located on the front first restraint surface A1, when the bucket 6 is swung upward, the tip of the bucket 6 becomes the first first restraint. In such a case, the bucket 6 can only be operated to swing downward from the current state (step S).
16).

(4) Next, the case where the operation of raising the first boom portion 4a and the operation of scraping the arm 5 are performed simultaneously in step S6 of FIG. 1 will be described. In steps S3 and S4 in FIG. 1 described above, the detection values of the potentiometers 36 to 39 are differentiated to calculate the moving direction and the moving speed of the tip and bottom of the bucket 6, so that the first boom portion 4a Based on the differential values of the detection values of the potentiometer 36 and the potentiometer 38 of the arm 5, it is detected that the raising operation of the first boom portion 4a and the squeezing operation of the arm 5 have started to be performed simultaneously (step S6). Equivalent).

As shown in FIGS. 1 and 2, when the raising operation of the first boom portion 4a and the squeezing operation of the arm 5 begin to be performed simultaneously, the squeezing of the arm 5 is generally performed as shown by a solid line in FIG. By the operation, the tip of the bucket 6 enters the front second restraint area B2 (step S17). in this case,
Hydraulic cylinder 1 of arm 5 in the same manner as front first restraint area B1
2 is decelerated, and as the tip of the bucket 6 enters the front second restraint area B2 and approaches the front second restraint surface A2, the hydraulic cylinder 12 is greatly decelerated (step S18).

Next, the tip of the bucket 6 is moved to the front second restraint surface A.
When the number reaches 2 (step S19), the hydraulic cylinder 12 of the arm 5 is stopped (step S20) (corresponding to the second braking means). Then, the raising operation of the first boom portion 4a is continuously performed as it is. With the raising operation of the first boom portion 4a, the tip of the bucket 6 moves upward along the front second restraint surface A2. It goes. In this manner, the tip of the bucket 6 moves upward along the front second restraining surface A2, and as shown in FIGS. 1 and 3, the tip of the bucket 6 moves from above the second restraining surface A2 to the first first restraint. Area B
1 (step S7), the hydraulic cylinder 11 of the first boom portion 4a is decelerated in the same manner as described above (step S8), and the tip of the bucket 6 is moved to the front first braking surface A.
1, the hydraulic cylinder 11 of the first boom portion 4a
Is stopped (step S11).

Further, the bucket 6 is operated by operating the arm 5 alone.
It is assumed that the raising operation of the first boom portion 4a and the scraping operation of the arm 5 start to be performed at the same time in a state in which the tip of the arm extends beyond the front second restraint surface A2 and enters the driving unit 27 side (steps S17 and S21). In this case, the hydraulic cylinder 12 of the arm 5 is immediately stopped (Step S).
20), only the raising operation of the first boom portion 4a is performed. Then, when the tip of the bucket 6 enters the front first restraint area B1 (step S7), the hydraulic cylinder 11 of the first boom portion 4a is decelerated (step S8). Reaches the front first restraint surface A1, the hydraulic cylinder 11 of the first boom portion 4a is stopped (step S11).

(5) Next, the lateral restraint surface C and the lateral restraint area B
3 will be described.
In the control device 19, as described above, the vertical angle of the first boom portion 4a, the left and right angle of the second boom portion 4b, the front-back angle of the arm 5 and the bucket 6 based on signals from the potentiometers 36 to 39, and the first boom portion The position of the left side surface of the bucket 6 is constantly calculated based on the length of the bucket 4, the second boom portion 4 b, the arm 5, and the length of the bucket 6.
The moving direction and moving speed of the left lateral side of the bucket 6 are calculated by differentiating the detection values of the potentiometers 36 to 39.

When the bucket 6 is positioned on the right side of the operation unit 27 as shown by the solid line in FIG. 6, the second boom portion 4b is oscillated by the hydraulic cylinder 7 toward the operation unit 27, and 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 operation speed of the hydraulic cylinder 7 is decelerated. In this case, the more the left lateral side of the bucket 6 enters the lateral restraint area B3 and approaches the lateral restraint surface C, the greater the speed reduction operation.

Conversely, the left lateral side of the bucket 6 is the lateral restraint surface C
When the second boom portion 4b is operated in a direction away from the vehicle, the operating speed of the hydraulic cylinder 7 of the second boom portion 4b is increased in the lateral restraint region B3, contrary to the above-described deceleration. When the vehicle leaves the lateral restraint area B3, the speed is returned to the original speed and the operation is performed. When the left lateral side of the bucket 6 reaches the lateral restraint surface C and is about to be operated to the operating unit 27 side even slightly beyond the lateral restraint surface C, the pilot valve 3
The pilot pressure of 5a and 35b disappears, and the control valve 25 stops the hydraulic cylinder 7 of the second boom portion 4b.

(6) Next, control of the backhoe device 3 in a region below the predetermined position D will be described. As described above, in the area above the predetermined position D shown in FIG. 4, the front first and second front restraint surfaces A1, A2, the lateral restraint surface C,
The front first and second front restraint areas B1 and B2 and the horizontal restraint area B3 are set for this, but in the area below the predetermined position D, only the front first restraint surface A1 is set. Therefore, the hydraulic cylinders 11, 12, and 7 of the backhoe device 3 operate at a speed based on the operations of the right and left operation levers 9, 10 and the operation pedal 26 until the tip of the bucket 6 reaches the front first restraining surface A1. Is done. When the tip of the bucket 6 reaches the front first restraint surface A1, the bucket 6
Such that the tip of the vehicle enters the driving section 27 side beyond the front first restraint surface A1 cannot be performed.

[Another Embodiment] In the above embodiment, the bucket 6
The front first and front second restraint surfaces A1 and A2 and the horizontal restraint surface C are set on the basis of the tip, bottom and left lateral side of
The potentiometer 39 in FIG. 8 is omitted, and the end of the arm 5 (bucket 6
First and front second check surfaces A on the basis of
1, A2 and the lateral restraint surface C may be set.

In the above-described embodiment, the operating positions of the right and left operating levers 9, 10 and the operating pedal 26 are electrically detected by the potentiometers 15 to 18, and the pilot valves 31a to 35b of the electromagnetic proportional pressure reducing valve type are used. The present invention is applied to the operation type control valves 21 to 25, and the present invention is applied to this type. However, the present invention may be applied to a backhoe having the following configuration. That is, the operation positions of the right and left operation levers 9, 10 and the operation pedal 26 are electrically detected by the potentiometers 15 to 18 without the provision of the above-described pilot valves 31a to 35b of the electromagnetic proportional pressure reducing valve type. A type in which the control valves 21 to 25 of the electromagnetic proportional pressure reducing valve type are operated based on the detected value. Also, without the potentiometers 15 to 18 described above, the right and left operation levers 9 and 1 are provided.
0, a type in which a pilot valve (not shown) is directly mechanically operated by operating the operation pedal 26, and the control valves 21 to 25 are switched by a pilot pressure from the pilot valve.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a middle flow of control in front first and second front restraint surfaces and front first and second front restraint areas.

FIG. 3 is a diagram showing a flow of the latter half of the control in the front first and second front restraint surfaces and the front first and second front restraint areas.

FIG. 4 is a schematic side view of the backhoe showing the first and second front restraint surfaces and the first and second front restraint areas.

FIG. 5 is a side view in a state where the tip of the bucket has reached the first and second front restraint surfaces.

FIG. 6 is a schematic plan view of the backhoe showing the first and second front restraint surfaces, the first and second front restraint regions, the lateral restraint surface, and the horizontal restraint region.

FIG. 7 shows each hydraulic cylinder, control valve,
Diagram showing the relationship between the pilot valve, right and left operating levers, etc.

FIG. 8 is an overall side view of the backhoe.

[Explanation of symbols]

 2 Swivel base 3 Backhoe device 4 Boom 5 Arm 6 Bucket 7, 11, 12, 13 Hydraulic cylinder 27 Operating unit 29, 30 External frame 36, 37, 38, 39 Position sensor 36, 38 Potentiometer A1 First braking surface A2 Second Check surface

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-306535 (JP, A) JP-A-4-333730 (JP, A) JP-A-5-272155 (JP, A) JP-A-3-302 156037 (JP, A) JP-A-3-228929 (JP, A)

Claims (2)

(57) [Claims] An operating unit (2) provided on a swivel (2).
A first setting means for setting in space a first restraining surface (A1) spaced a predetermined distance forward from the outer frames (29) and (30) covering the outermost surface of (7), and a bucket of the backhoe device (3); A position sensor (3) for detecting the position of (6)
6), (37), (38), and (39), and the position sensors (36), (37), (38), and (3).
Based on the detection of 9), when the bucket (6) attempts to enter the operating section (27) side beyond the first restraint surface (A1), the hydraulic cylinder (7) for driving the backhoe device (3), (11) A first restraint means for stopping (12), (13) and restraining it, and a second restraint surface (A2) further away from the first restraint surface (A1). Second setting means for setting the position on the space; detecting means for detecting that the raising operation of the boom (4) of the backhoe device (3) and the scraping operation of the arm (5) are simultaneously performed; When the boom (4) is raised and the arm (5) is squeezed simultaneously based on the detecting means, the bucket (6)
Reaches the second restraint surface (A2), the second hydraulic cylinder (12) for driving the arm (5) is stopped.
Backhoe with check means. 2. The position sensors (36), (37),
(38) and (39) are potentiometers (36) for detecting an angle of the boom (4) with respect to the swivel (2), and a potentiometer (36) for detecting an angle of the arm (5) with respect to the boom (4). 38)
The detecting means includes the potentiometers (36) and (3).
2. The backhoe according to claim 1, wherein a simultaneous operation of raising the boom (4) and scraping the arm (5) is detected based on a change in the detected value of (8).