JPH0617453A - Back hoe - Google Patents

Abstract

PURPOSE:To make a bucket so as not to come into contact with a pipeline of the like being buried in the ground in the case where the ground is digged by a back hoe. CONSTITUTION:This back hoe is provided with three height sensors 20, 27 and 30 detecting a fact that a bucket 6 of a back hoe unit 3 is situated how far beneath from a machine body 2, and a setting means setting a higher a limiting position E than the lowest position of a mechanical limitation in this bucket 6. When the bucket reaches the limit position E, any operation of the bucket 6 to the down side going beyond this limiting position E is checked and prevented by way of stopping three hydraulic cylinders 7, 11 and 12. Subsequently, this checking action is artificially selected into an operating state and an unoperating state in a free operational manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for limiting excavation depth of a backhoe mounted on a backhoe.

[0002]

2. Description of the Related Art A backhoe equipped with a backhoe is a boom which is vertically swingably connected to a swivel base.
An arm that is swingably connected to the tip of the boom and a bucket that is swingably connected to the tip of the arm are main members. Further, the boom and the arm are generally configured to be swingable upward and downward to the mechanical operation limit.

[0003]

In the case of excavating work with a backhoe in an urban area, there has been an increasing demand in recent years to enable accurate excavation from the ground to a desired depth. This is because many types of pipes such as gas pipes, electricity and telephones are buried in urban areas, so when excavation work is performed in the vicinity of these pipes, it is necessary to accurately excavate them from the ground to the desired depth. This is because it is necessary to carry out the excavation work without the bucket coming into contact with the pipe. However, since the operator operating the backhoe in the above-mentioned backhoe is the operator sitting on the driver's seat of the swivel, the operator and the bucket are inevitably separated from each other. Therefore, when the operator in the driver's seat performs excavation work while visually observing the bucket and piping, it is difficult to operate the bucket accurately to the desired depth, and the bucket is operated incorrectly beyond the desired depth. If it does, the bucket may come into contact with the pipe. An object of the present invention is to enable a backhoe to perform an accurate excavation work at a desired depth from the ground.

[0004]

A feature of the present invention is that the backhoe as described above is configured as follows. That is, [1] a height sensor that detects how much the bucket of the backhoe device is located below the machine body, and setting means that sets a limit position higher than the lowest mechanical limit position of the bucket of the backhoe device. Then, when the bucket of the backhoe device reaches the limit position based on the detection of the height sensor, the operation of the bucket toward the descending side beyond the limit position is stopped by stopping the hydraulic cylinder for driving the backhoe device. The restraint means is provided, and the restraint means is provided with a switching means that can be manually switched between an operating state and an operation stop state. [2] In the configuration of [1] above, the setting means is configured to set the detection value of the height sensor when there is an artificial setting command as the limit position.

[0005]

[Action]

[I] With the configuration as described in [1] above, when excavating work in a work site where pipes are buried,
The depth from the ground to a position slightly above the pipe may be set at the limit position of the bucket. As a result, if the operator accidentally lowers the boom or arm and the bucket reaches the above-mentioned limit position, the hydraulic cylinder is stopped by the restraining means, so that the boom or arm should be further lowered. Also, this operation cannot be performed. On the contrary, when the excavation depth is not limited, such as in a work site where pipes and the like are not particularly buried, the check means may be switched to the operation stop state by the switch means. As a result, the bucket can be operated to the lowest position of its mechanical limit to perform excavation work.

[II] In the case of the construction of [1] above, it is important how to set the limit position of the bucket. Therefore, if it is configured as in the above item [2], the ground is first excavated a little with a backhoe, a scoop, etc., and the piping is exposed a little. Next, the backhoe bucket is slowly moved down, the tip of the bucket is brought to the position of the above-mentioned pipe, and at this time, the operator operates a switch to artificially issue a setting command. Then, based on this setting command, the position of the bucket at this time (the position when the tip of the bucket is at the position of the above-mentioned pipe) is set and stored as the limit position.
In this way, the bucket is actually taken to the limit position in advance, and the limit position is set and stored, so that the limit position can be set accurately. Further, by repeating the above operation, the limit position can be easily changed.

[0007]

According to the present invention, when the excavation depth is limited, the limit position is set / changed, so that even if an operator accidentally lowers the bucket, the bucket is piped or the like. It became possible to perform excavation work without touching the ground, and it was possible to improve the workability of the backhoe. According to the second aspect of the invention, the limit position can be set by actually bringing the bucket to the limit position in advance, so that the limit position can be set accurately, and the bucket and the pipe and the like can be set. The accuracy of contact avoidance can be improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the entire side surface of the backhoe, in which a swivel base 2 (corresponding to a machine body) is supported on an upper portion of a rubber crawler type traveling device 1, and a backhoe device 3 is provided in a front portion of the swivel base 2. . 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. As shown in FIG. 1, 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 swingably connected around a front end axis P1 of the first boom portion 4a, and a swingable connection around a front end axis P2 of the second boom portion 4b. Support bracket 4c, 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, the arm 5 and the bucket 6 are horizontally moved in parallel.

As shown in FIG. 1, the control valve 21 for the hydraulic cylinder 11 of the boom 4 and the hydraulic cylinder 12 of the arm 5 are shown.
A control valve 22 for the hydraulic cylinder 13, 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. This control valve 21-2
Reference numeral 4 is a 3-position switching type electromagnetic proportional pressure reducing valve type capable of controlling the flow rate. In addition, the three-position switching control valve 2 for the hydraulic cylinder 7 of the second boom portion 4b of the boom 4 is used.
5 is provided.

As shown in FIGS. 1 and 2, 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 control valve 21 is operated to the descending side or the ascending side of the boom 4, and when the right operating lever 9 is operated to the right or the left, the control valve 23 is discharged to the earth side of the bucket 6. Or it is operated to the scraping side. When the left operation lever 10 is operated forward or backward, the control valve 22 is operated to the raising side or the scraping side of the arm 5, and when it is operated to the right or left, the control valve 24 is operated to the right turning side or the left turning side. It Further, by depressing the operation pedal 26 to the right or left, the control valve 25 is operated to the right or left swinging 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 control valve 21
.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.

As shown in FIGS. 2 and 1, an angle sensor 20 (corresponding to a height sensor) for detecting the vertical angle of the first boom portion 4a with respect to the swivel base 2 and the first boom portion 4a.
An angle sensor 30 (corresponding to a height sensor) that detects a right-and-left angle of the second boom portion 4b with respect to and a angle sensor 27 (corresponding to a height sensor) that detects a longitudinal angle of the arm 5 with respect to the support bracket 4c are provided. .

In the control device 19, the angle sensor 2
Detection values of 0, 27, 30 and the first and second boom parts 4
The angle sensor 27 from the ground G based on the lengths of a and 4b.
The height from the ground G to the position A at the tip of the hydraulic cylinder 12 is calculated by calculating the height up to the position and multiplying the calculated value by a coefficient. Then, the height from the ground G to the tip of the arm 5 is calculated from the calculated value of the height to the position of the angle sensor 27, the detected value of the angle sensor 27, and the length of the arm 5, and the calculated value is also calculated. Is multiplied by a coefficient to calculate the height from the ground G to the position B of the tip of the hydraulic cylinder 13. First
If the vertical angle of the boom portion 4a is small, the height from the ground G to the position B calculated above is a set value (bucket 6).
Height) will be a negative value. In this case, the negative value is the excavation depth from the ground G to the tip of the bucket 6.

The backhoe is constructed so that the upper limit of the operation of the backhoe device 3 can be set. Next, the control relating to the setting of the upper limit will be described. Figure 3
Further, as shown in FIG. 1, the swivel base 2 is provided with a push-on / push-off type upper limit switch 28. When the upper limit switch 28 is operated to the OFF position (step S1), the boom 4 and the arm It becomes a normal excavation work state in which 5 can be operated up to the mechanical operation limit.

When the work height is limited, such as inside a building, the right and left operating levers 9,
10 is operated to operate the tip of the boom 4 or the arm 5 to near the ceiling of the building, and at this time, the upper limit switch 28 is operated to the ON position (step S1). In this case, the controller 19 calculates the height from the ground G to the position A in FIG. 2 and the height from the ground G to the position B as described above (steps S2 and S3), 2
The higher one of the heights of the set is set as the upper limit position C (see FIG. 2) (step S4). A deceleration region D (see FIG. 2) is set between the upper limit position C and a position below the upper limit position C by a set distance (step S5).

Next, the operator operates the right and left operating levers 9 and 10.
Will be operated to operate. During this operation, the current height from the ground G to the position A and the height from the ground G to the position B are calculated (steps S6 and S).
7) When the height from the ground G to the position B is a plus value with respect to the above-mentioned set value (height of the bucket 6) (when the bucket 6 is located above the ground G) (step S8) ), The height of position A and the height of position B are compared as shown in FIG. 4 (step S9).

When the position A is higher and the position A is within the deceleration region D (step S10), the position shown in FIG.
The control valves 21, 25 of the hydraulic cylinders 11 and 7 for the first and second boom portions 4a and 4b are operated so that the opening degrees of the control valves 21 and 25 are closed.
The operating speed of is decelerated (step S11). When the position A is higher and the position A has reached the upper limit position C (step S12), even if the right operation lever 9 is operated to the upward side of the first boom portion 4a,
Further, even if the operation pedal 26 is operated to the ascending side of the second boom portion 4b (the left and right center side of the swing range), the control device 19 operates the control valves 21 and 25 of FIG. 1 to the neutral position,
The operation of the hydraulic cylinders 11 and 7 to the upward side is blocked (step S13). On the contrary, the operation from the upper limit position C to the lower side of the first and second boom portions 4a and 4b can be performed.

On the contrary, when the position B is high and the position B is within the deceleration area D (steps S9 and S14),
Regardless of the operating position of the left operating lever 10, the control valve 2 of FIG.
The opening degree of 2 is operated to the closing side, and the operating speed of the hydraulic cylinder 12 for the arm 5 is decelerated (step S1).
5). Then, similarly, the opening degrees of the control valves 21 and 25 of FIG. 1 are also operated to the closing side, and the first and second boom portions 4a and 4b are
The operating speed of the hydraulic cylinders 11, 7 for use is decelerated (step S16).

When the position B is high, the position B
Has reached the upper limit position C (step S1
7) Even if the left operation lever 10 is operated to the rising side of the arm 5, the control device 19 operates the control valve 22 of FIG. 1 to the neutral position to prevent the hydraulic cylinder 12 from being operated to the rising side. (Step S18). On the contrary, the operation from the upper limit position C to the descending side of the arm 5 can be performed as usual. Then, when the operation proceeds to step 13 and the right operation lever 9 is operated to the ascending side of the first boom portion 4a, the operation pedal 2
Even if 6 is operated to the ascending side of the second boom portion 4b (left and right center of the swing range), the control device 19 operates the control valves 21 and 25 of FIG.
The operation of 1, 7 on the ascending side is blocked. On the contrary, the operation from the upper limit position C to the lower side of the first and second boom portions 4a and 4b can be performed.

During this work, the upper limit switch 28 is turned off.
If the operation is continued at the N position, the process returns from step S19 to step S6 of FIG. 3 and the upward restraint of the boom 4 and the arm 5 is always performed as described above. Then, if the upper limit switch 28 is operated to the OFF position during this work, the process moves from step S19 to step S1 of FIG. 3, the upper limit position C is erased (step 20), and the normal excavation work state is restored.

Further, when it is desired to change the upper limit position C during work, the upper limit switch 28 is once turned on from the ON position.
Operate to the FF position. Then, the tip of the boom 4 or the tip of the arm 5 may be operated to a desired height and the upper limit switch 28 may be operated to the ON position again. As a result, the upper limit position C is newly set, and the deceleration region D is set for the new upper limit position C.

This backhoe is constructed so that the lower limit of the operation of the backhoe device 3 can be set. Next, the control relating to the setting of this lower limit will be described. Figure 5
Further, as shown in FIG. 1, the swivel base 2 is provided with a push-on / push-off type lower limit switch 29 (corresponding to a switching means), and if this lower limit switch 29 is operated to the OFF position (step S21). ), The boom 4 and the arm 5 are in a normal excavation work state in which the boom 4 and the arm 5 can be lowered to their mechanical operation limits.

When excavating to a desired depth, the right and left operating levers 9 and 10 are operated to lower the bucket 6 from the ground G to a desired depth, and at this time, the lower limit switch 29. Is operated to the ON position (corresponding to an artificial setting command) (step S21). In this case, the control device 19 calculates the depth from the ground G to the position B in FIG. 2 (negative value with respect to the set value (height of the bucket 6) described above) as described above (step S22). The depth is set as the lower limit position E (corresponding to the limit position) (step S23) (corresponding to setting means).

Next, the operator operates the right and left operating levers 9 and 1.
The excavation work is performed by operating 0, and the current height (depth) from the ground G to the position B is calculated during the excavation work (step S24). And the ground G
When the height from the position B to the position B is a negative value with respect to the set value (the height of the bucket 6) described above (when the bucket 6 is located below the ground G) (step S
25) If the position B has reached the lower limit position E (step S26), even if the right operation lever 9 is operated to the lower side of the first boom portion 4a, the left operation lever 10 is scratched by the arm 5. Even if it is operated to the retracted side or the operation pedal 26 is operated to the descending side of the second boom portion 4b (the left and right center side of the swing range), the control device 19 causes the control valve 21,
22 and 25 are operated to the neutral position, the hydraulic cylinder 7,
The operation of 11, 12 to the descending side is blocked (step S
27, S28) (corresponding to the restraint means). On the contrary, the operation from the lower limit position E to the ascending side of the first and second boom portions 4a and 4b and the arm 5 can be performed.

During this excavation work, the lower limit switch 2
If the 9 is still in the ON position, step S29
Then, the process returns to step S24, and the above-described restraint on the descending side of the boom 4 and the arm 5 is always performed. If the lower limit switch 29 is operated to the OFF position during this work,
The process moves from step S29 to step S21, the lower limit position E is erased (step 30), and the normal excavation work state is restored.

If it is desired to change the lower limit position E during excavation work, the lower limit switch 29 is operated once from the ON position to the OFF position. Then, the bucket 6 may be operated to a desired depth and the lower limit switch 29 may be operated to the ON position again. As a result, the lower limit position E is newly set. As described above, the upper limit position C and the lower limit position E shown in FIG. 2 can be set independently of each other, and it is possible to set one and not the other.
The deceleration area D is set only for the upper limit position C, and is not set for the lower limit position E.

[Other Embodiment] In the above embodiment, the tip of the bucket 6 is actually lowered to a desired depth,
The lower limit switch 29 was operated to the ON position to set the lower limit position E, but a volume type setting switch (corresponding to setting means) for generating a voltage corresponding to the depth from the ground G.
Is provided to control the voltage from the setting switch 19
It may be configured such that the depth corresponding to this voltage is set to the lower limit position E. In this case, the operator can arbitrarily set the lower limit position E by operating the setting switch, and the lower limit switch 29 as in the above-described embodiment.
The lower limit position E can be changed at any time in the ON position without operating the switch to the OFF position. Then, such a volume type setting switch may be provided for setting the upper limit position C.

In the embodiment described above, the angle sensor 2
0, 27, 30 allow the first and second boom portions 4a,
4b and the angle of the arm 5 is detected, an angle sensor (not shown) for detecting the angle of the bucket 6 with respect to the arm 5 is provided at the connection point between the arm 5 and the bucket 6 shown in FIG. You can go. In this case, as shown in FIG. 2, the bucket 6 is prevented from exceeding the lower limit position E when the first boom portion 4a is operated to the descending side and the arm 5 is operated to the scraping side. Then, based on the detection value of the angle sensor that detects the angle of the bucket 6 with respect to the arm 5, the bucket 6 with respect to the arm 5 is moved so that the back surface of the bucket 6 moves in parallel along the lower limit position E.
The angle may be controlled. This allows
A parallel excavation surface along the lower limit position E is obtained.

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 configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a linked state of hydraulic cylinders, control valves, right and left operating levers, upper and lower switches, etc. of a backhoe.

[Fig. 2] Overall side view of the backhoe

FIG. 3 is a diagram showing a flow of a first half of control for an upper limit position.

FIG. 4 is a diagram showing a flow of the latter half of the control for the upper limit position.

FIG. 5 is a diagram showing a control flow for a lower limit position.

[Explanation of symbols]

 2 Airframe 3 Backhoe device 6 Bucket of backhoe device 7, 11, 12 Hydraulic cylinder 20, 27, 30 Height sensor 29 Switching means E Limit position

Claims (2)

[Claims] 1. Bucket (6) of a backhoe device (3)
Height sensors (20), (27), (30) that detect how far below the fuselage (2) is, and the minimum mechanical limit of the bucket (6) of the backhoe device (3). Setting means for setting a limit position (E) higher than the position, and the height sensors (20), (27), (3)
When the bucket (6) of the backhoe device (3) reaches the limit position (E) based on the detection of 0), the operation of the bucket (6) to the descending side beyond the limit position (E) is performed. , A check means for stopping by stopping the hydraulic cylinders (7), (11), (12) for driving the backhoe device (3), and artificially putting the check means into an operating state and a non-operating state. A backhoe provided with a switching means (29) that can be freely switched. 2. The detection values of the height sensors (20), (27), (30) when an artificial setting command is given,
The backhoe according to claim 1, wherein the setting means is configured to set the limit position (E).