JPH07309451A - Bucket excavator for unloader - Google Patents

Abstract

PURPOSE:To provide a bucket excavator for an unloader by which the occurrence of excessive excavating reaction of a bucket can be prevented and a load applied to a bucket chain line can be maintained within a certain range. CONSTITUTION:When a detecting value (excavating reaction P1 of a bucket 9) of a pressure detector 18 exceeds a preset value, a shock absorbing hydraulic cylinder 15 is contractively driven by a bucket excavating reaction control part 19, and a rear guide sprocket 16 is upward moved, and a biting-in quantity of the bucket 9 is reduced, and the excavating reaction P1 of the bucket 9 is reduced. The excavating reaction P1 of the bucket 9 and a load applied to a bucket chain line 8 are accurately found according to the detecting value of the pressure detector 18 and a detecting value of a bucket load detector 10 by a bucket load control part 20 or the like, and traversing speed of an excavating part, a biting-in quantity of the bucket 9 or moving speed of the bucket 9 are controlled according to these, and the excavating reaction P1 of the bucket 9 and the load applied to the bucket chain line 8 are controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bucket excavator for an unloader, and is useful when applied to a case where a cutting reaction force of a bucket or a load applied to a bucket chain line is controlled.

[0002]

2. Description of the Related Art FIG. 8 is a side view showing a bucket excavator of an unloader according to a conventional technique. In the figure, 1 is a vertical boom, 2 is a parallel link, 3 is an L frame, 4 is a vertical column, 5 is a vertical frame, 5a is an upper mounting shaft, 5b is a swing hydraulic cylinder, 6 is an intermediate guide sprocket, and 7
Is a drive sprocket, 8 is a bucket chain line, 8a
Is a bucket chain, 9 is a bucket, 10 is a bucket load detector, 50 is a bottom frame, 50a is a connecting shaft, 50
b is a cylinder, 51 is a rear guide sprocket, 52 is a front guide sprocket, 53 is a load adjusting control unit, 1
1 is a bulk cargo loaded on a carrier.

Of these, the elevation boom 1 is provided on the upper part of the unloader, and the vertical column 4 and the like are moved up and down by the elevation movement. The parallel link 2 is provided parallel to the elevation boom 1 and performs an elevation operation together with the elevation boom 1. The L frame 3 supports the vertical column 4 at the lower end, and the upper end and the intermediate part are rotatably supported by the parallel link 2 and the tip ends of the elevation boom 1 so that the horizontal posture of the lower end is maintained. Has been done.

The upper end of the vertical frame 5 is connected to the lower end of the vertical column 4 via a shaft 5a, and the middle part is
A cylinder 5b whose one end is supported by the lower end of the vertical column 4.
Is connected to the other end of the cylinder 5 and is swung about the shaft 5b by the expansion and contraction of the cylinder 5b. Bottom frame 50
The rear end (the right end in FIG. 7) is connected to the lower end of the vertical frame 5 via a connecting shaft 50a, and the intermediate part is connected to the other end of the cylinder 50b whose one end is supported by the vertical frame 5. The cylinders 50b are connected to each other, and by the expansion and contraction of the cylinder 50b, the cylinders 50b are swung about the connecting shaft 50a to be held horizontally and have a substantially L shape together with the vertical frame 5. The bottom frame 50 also has a tension holding cylinder (not shown) built therein, and the tension holding cylinder expands and contracts in the longitudinal direction to hold the tension of the bucket chain 8a.

The drive sprocket 7 is provided in the upper end chamber of the vertical column 4 and engages with the bucket chain 8a to drive the bucket chain 8a so as to circulate in the direction of arrow A. The intermediate guide sprocket 6, the rear guide sprocket 51 and the front guide sprocket 52 are
Each of them is provided near the lower end of the vertical column 4, at the rear end of the bottom frame 50 (on the shaft 50a) and at the tip of the bottom frame 50. The bucket chain 8a engages with the bottom chain 50a. , Along the vertical frame 5 and the vertical column 4 so as to make circular movement in the direction of arrow A in a substantially L shape. A large number of buckets 9 are attached to the bucket chain 8a at a predetermined interval to form a bucket chain line 8 together with the bucket chain 8a, and move in a direction of arrow A along with the bucket chain 8a.

The bucket load detector 10 is provided in the drive system of the drive sprocket 7, detects the load applied to the bucket chain line 8, and outputs a detection signal to the load adjusting control unit 53. The load adjustment control unit 53 inputs a detection signal from the bucket load detector 10 and prevents the bucket 9 from being overloaded according to the detection signal.
The traverse speed of the excavation section (hereinafter simply referred to as the excavation section) including the vertical column 4 and the bucket chain line 8, the biting amount of the bucket 9 with respect to the bulk cargo 11, or the traveling speed of the bucket chain line 8, that is, the movement of the bucket 9. Control the speed.

Therefore, according to the bucket excavating device of the unloader having the above-described structure, when the bucket 9 travels (travels) in the direction perpendicular to the plane of FIG. 8 and moves cyclically along the bucket chain line 8, the bucket 9 is moved to the front guide sprocket 52. Scrap the bulk load 13 while horizontally moving backward (toward the rear guide sprocket 51) after passing, and scoop up the bulk load 11 scraped when turning the opening upward through the rear guide sprocket 51. Then, it is received inside and conveyed to the inside of the vertical column 4 above, and at the time when the opening is turned downward via the drive sprocket 7, the internal bulk load 11 is discharged. In this way, the bulk cargo 11 is unloaded.

At this time, when the value detected by the bucket load detector 10 exceeds the set value, the load adjusting control unit 53 controls the traverse speed of the excavating unit to decrease, the amount of biting of the bucket 9 to decrease, or the bucket. The bucket chain line 8 is prevented from being overloaded by controlling the movement speed of the bucket 9 to be reduced.

[0009]

However, in the bucket digging device for the unloader according to the above-mentioned conventional technique, the weight of the bucket 9 and the bulk load 11 being conveyed by these buckets 9 is included in the detection value of the bucket load detector 10. , The excavation reaction force P ₁ when the bucket 9 scrapes the bulk load 11
Is included, and this excavation reaction force P ₁ alone cannot be grasped separately from the detected value.

Therefore, even if the detection value of the bucket load detector 10 is within the reference value, if the ratio of the excavation reaction force P ₁ in this detection value is large, that is, the excavation reaction force P ₁ is There is a case where it becomes excessive, and in such a case, the excavation reaction force P ₁ causes an arrow 5 to appear below the vertical column 4.
The bending force shown by 4 acts, and abnormal vibration may occur in the vertical column 4. In addition, when the detection value of the bucket load detector 10 exceeds the set value, when the avoidance operation for raising the vertical column 4 is performed, the total weight of the vertical column 4 is raised, and therefore the elevation boom 1 is raised. There is an uneconomical economy that requires a large driving force.

Therefore, in view of the above-mentioned prior art, the present invention prevents the generation of an excessive reaction force for excavating the bucket, and sets the load (weight of the bucket and the bulk load being conveyed by the bucket) on the bucket chain line within a certain range. An object of the present invention is to provide a bucket excavator for an unloader that can be retained inside.

[0012]

According to a first aspect of the present invention that achieves the above object, a bucket chain line having a bucket chain and a bucket attached to the bucket chain is driven vertically by a drive sprocket. In a bucket excavator of an unloader having a column and an excavation unit configured to cyclically move along a frame provided at a lower end of the vertical column, a lower end of the excavation unit and a downstream end of the bucket chain line in a moving direction. A guide sprocket arranged to occupy a portion of the guide chain and engaged with the bucket chain to guide the bucket chain in the direction of the vertical column; and a base end portion of which is swingably supported by the frame. , Swing arm that rotatably supports the guide sprocket at the tip, and the base end can swing to the frame While being supported, the tip portion is characterized in that a cushioning member connected to the guide sprocket with coordinated occupied in the moving direction downstream side of the bucket chain lines than the proximal portion.

According to a second aspect of the present invention that achieves the above object, in the bucket excavator of the unloader of the first configuration, the buffer member is a buffer cylinder, the pressure detector of the buffer cylinder, and A control means for controlling the expansion and contraction of the buffer cylinder based on the detection value of the pressure detector to control the excavation reaction force of the bucket.

A third structure of the present invention which achieves the above object is, in the bucket excavating device of the unloader of the first structure, the buffer member is a buffer cylinder, and a pressure detector of the buffer cylinder and a drive are provided. Apply the bucket load detector on the sprocket and the excavation reaction force of the bucket or the bucket chain line by controlling the traverse speed of the excavation section, the amount of biting of the bucket or the moving speed of the bucket based on the detection values of these detectors. And a control means for controlling the load.

[0015]

According to the first aspect of the present invention, when the excavation reaction force of the bucket increases, the excavation reaction force causes the cushioning member to contract and the cushioning member and the swing arm to swing upward. As a result, the guide sprocket moves upward, and along with this, the guide sprocket side of the bucket chain line that occupies the lower part of the frame moves upward, which reduces the biting amount of the bucket and reduces the bucket reaction force. To do. Thus, excessive excavation reaction force of the bucket is prevented, and abnormal vibration of the vertical column portion is surely prevented. Further, even when a strong thrusting force is applied to the bucket from the floor of the hold or the like during excavation of a bottom load, the guide sprocket moves upward in the same manner as above, so that the thrusting force is absorbed and the structure is increased. Things are protected. Furthermore, the tension of the bucket chain can be maintained by the urging force of the buffer member.

According to the second aspect of the present invention, the excavation reaction force of the bucket is detected by the pressure detector. When this detected value exceeds the set value, the buffer cylinder is contracted and driven by the control means, and at the same time, the buffer cylinder and the swing arm swing upward. As a result, the guide sprocket moves upward, and accordingly, the guide sprocket side of the bucket chain line that occupies the lower part of the frame moves upward, which reduces the biting amount of the bucket and reduces the bucket excavation reaction force. Decrease. Thus, excessive excavation reaction force of the bucket is prevented, and abnormal vibration of the vertical column portion is surely prevented. The guide sprocket also moves upward in the same manner as above even when a strong thrust force is applied to the bucket from the floor of the hold, etc. when excavating the bottom load and the detected value of the pressure detector exceeds the set value. For,
As a result, the thrust force is absorbed and the structure is protected.

According to the third aspect of the present invention, the excavation reaction force of the bucket is detected by the pressure detector. When the detected value exceeds the set value, the control means performs the deceleration control of the traverse speed of the excavation unit, the reduction control of the biting amount of the bucket by the raising operation of the excavation unit, or the deceleration control of the moving speed of the bucket, Bucket excavation reaction force is reduced.
Thus, excessive excavation reaction force of the bucket is prevented,
Abnormal vibration of the vertical column portion is reliably prevented.
Further, the control means subtracts the detection value of the pressure detector (the excavation reaction force of the bucket) from the detection value of the bucket load detector to thereby apply the load on the bucket chain line (the weight of the bucket and the bulk load being conveyed by the bucket). ) Is accurately obtained, and the traverse speed control of the excavation section, the bite amount control of the bucket by the ascending / descending operation of the excavation section, or the bucket speed control is performed so as to keep this load within a certain range. In this way, the fixed-quantity dispensing operation of bulk cargo is realized easily and surely.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. The same parts as those in the conventional technique (FIG. 8) are designated by the same reference numerals, and a detailed description thereof will be omitted.

FIG. 1 is a side view showing a bucket excavating device for an unloader according to an embodiment of the present invention, FIG. 2 is an enlarged view showing a portion near a rear guide sprocket in FIG.
2 is a view taken along the line III-III in FIG. 2, FIG. 4 is an enlarged side view showing the vicinity of the bottom frame of FIG. 1 and showing a state during normal operation, and FIG. FIG. 7 is an enlarged side view showing the vicinity of the bottom frame and showing a state during overexcavation reaction force avoidance operation, FIG. 6 is a block diagram showing details of the bucket load control unit shown in FIG. 1, and FIG. It is a flowchart which shows the processing content of each part in the bucket load control part shown in FIG.

In these figures, 1 is a boom for elevation and 2 is a boom.
Is a parallel link, 3 is an L frame, 4 is a vertical column, 5 is a vertical frame, 5a is an upper mounting shaft, 5b is an oscillating hydraulic cylinder, 6 is an intermediate guide sprocket, 7 is a drive sprocket, 8 is a bucket chain line, 8a Is a bucket chain, 9 is a bucket, 10 is a bucket load detector, 12 is a bottom frame, 12a is a connecting shaft, 12b is a rocking cylinder, 13 is a rocking arm, 14 is an arm mounting shaft, 15 is a buffer hydraulic cylinder, and 15a. Is a cylinder mounting shaft, 16 is a rear guide sprocket, 16a is a rotating shaft, 17 is a guide roll base, 17a is a roller, 18 is a pressure detector, 19 is a bucket excavation reaction force control unit, 20 is a bucket load control unit, 2
Reference numeral 0a is a calculation unit, 20b is a load determination unit, 20c is a control instruction unit, 21a is a vertical column lateral movement system control unit, 21b is a boom and elevation system control unit, 21c is a bucket speed system control unit, 11
Is a bulk cargo loaded on a carrier.

As shown in FIGS. 1 to 3, the bottom frame 12 has its rear end (the right end in FIG. 1) deflected upward,
The rear end of this deflector is connected to the lower end of the vertical frame 5 by the connecting shaft 1.
The intermediate portion is connected to the other end of the swing cylinder 12b, one end of which is supported by the vertical frame 5, and the swing shaft 12a is expanded and contracted to center the connection shaft 12a. It is rocked and held horizontally, and forms a substantially L shape with the vertical frame 5. The bottom frame 12 also has a tension holding cylinder (not shown) built-in, and the tension holding cylinder expands and contracts in the longitudinal direction to hold the tension of the bucket chain 8a. The front guide sprocket 52 is rotatably provided at the tip of the bottom frame 12 and engages with the bucket chain 8a to guide the bucket chain 8a rearward (toward the rear guide sprocket 16).

The rear guide sprocket 16 is disposed below the deflecting portion of the bottom frame 12 and is engaged with the bucket chain 8a to move the bucket chain 8a upward (toward the vertical column 4). invite. The swing arm 13 is swingable to the bottom frame 12 via an arm attachment shaft 14 provided at the lower end of the bottom frame 12 so as to project from both side surfaces of the bottom frame 12 (see FIG. 3). While being supported, the rear guide sprocket 16 is rotatably supported at the tip end portion which is located rearward of the base end portion (downstream side in the moving direction of the bucket chain line 8). The shock-absorbing hydraulic cylinder 15 has a base end portion swingably supported by the bottom frame 12 via cylinder mounting shafts 15a (see FIG. 3) projectingly provided on upper portions of both side surfaces of the bottom frame 12, respectively. The tip end portion is located rearward of the base end portion (downstream side in the moving direction of the bucket chain line 8) and is coupled to the tip end portion of the swing arm 13.

The solid line in FIG. 2 (however, the chain line for the bucket chain line 8) is the state when the buffer hydraulic cylinder 15 is extended and driven (FIG. 4 corresponds to the state at this time). The chain double-dashed line is the buffer hydraulic cylinder 15.
Is the state when the contraction drive is performed at all (FIG. 5 corresponds to the state at this time). That is, when the state shown by the solid line changes to the state shown by the chain double-dashed line, the buffer hydraulic cylinder 1
When 5 is contracted and driven, the buffer hydraulic cylinder 15 and the swing arm 13 swing upward, and the rear guide sprocket 16 moves upward. Of course, in the state indicated by the chain double-dashed line, the rear guide sprocket 16 is configured so as not to interfere with the connecting shaft 12a of the vertical frame 5 and the bottom frame 12.

The guide roll base 17 is the bottom frame 1
2 is provided at the lower end of the front end portion. The guide roll base 17 has a plurality of rollers 17a arranged downward along the moving direction of the bucket chain 8a and is adjustable so as to extend downward by a certain height. The roller 17a contacts the bucket chain 8a. Contact this bucket chain 8a
To guide you. As shown in FIG. 4, the guide roll base 1
7 extends downward and pushes down the bucket chain line 8, so that the bucket chain line 8 is parallel to the bottom frame 12 (a portion excluding the deflection portion) between the guide roll base 17 and the rear guide sprocket 16. The lower limit position of the rear guide sprocket 16 is set. Therefore, as shown in FIG. 5, when the rear guide sprocket 16 moves upward, the bucket chain line 8 inclines upward toward the rear guide sprocket 16 between the guide roll base 17 and the rear guide sprocket 16. Therefore, the biting amount of the bucket 9 during this period is reduced, and the excavation reaction force P ₁ of the bucket 9 is reduced.

The pressure detector 18 is provided to buffer the hydraulic cylinder 15, the drilling reaction force P ₁ of the bucket 9 by detecting the hydraulic pressure of the cushioning hydraulic cylinder 15 that varies depending on the excavation reaction force P ₁ of the bucket 9 To detect.

As shown in FIG. 6, the bucket load control unit 20 has a calculation unit 20a, a load determination unit 20b, and a control instruction unit 2.
It has 0c. As shown in S100 to S106 of FIG. 7, the calculation unit 20a inputs detection signals from the pressure detector 18 and the bucket load detector 10 (see S100), and the bucket 9 of the bucket 9 is detected based on the detection value of the pressure detector 18. The excavation reaction force P ₁ is calculated, and the bucket load detector 10
Of the load on the bucket chain line 8 (the bucket 9 and the bulk load 11 being conveyed by these buckets) by obtaining the difference between the detected value of the
Weight) of the load determination unit 20b.
(S101).

The calculation result from the load determination unit 20b in the arithmetic unit 20a, i.e. enter the value of the load applied to the excavation reaction force P ₁ and the bucket chain line 8 of the bucket 8, excavation reaction force P ₁ is the upper limit set value of the bucket 8 It is determined whether or not (see S102). If it is determined that the upper limit set value is exceeded, the determination result is output to the control instruction determination unit 20c, while if it is determined that the upper limit set value is not exceeded, the bucket chain line 8 is subsequently operated. It is determined whether the load deviates from a certain range (S103).
reference). If it is determined that the deviation is not within the certain range, the process returns to the first process (see S100), while if it is determined that the deviation is not within the certain range, the load applied to the bucket chain line 8 is continuously applied. Is above the upper limit set value (if the upper limit set value is not exceeded, it means that the lower limit set value is exceeded) (S10
4) The result of this determination is output to the control instruction unit 20c.

In the control instruction unit 20c, when the load determination unit 20 determines that the excavation reaction force P ₁ of the bucket 9 exceeds the upper limit set value, or when the excavation reaction force P _{1 of the} bucket 9 is exceeded.
Is determined not to exceed the upper limit set value and the load applied to the bucket chain line 8 exceeds the upper limit set value (see S102, S103, S104), the vertical column lateral movement system control unit 21a. To the boom / elevation system control section 21b or to the bucket speed system control section 21c (see S105). In response to this, the vertical column lateral movement system control unit 21a,
In the boom / elevation system control unit 21b or the bucket speed system control unit 21c, the traverse speed deceleration control of the excavation unit, the bucket 9 is performed.
And the moving speed deceleration control of the bucket 9 are performed.

Further, in the control instruction section 20c, the load determination section 2
At 0, the excavation reaction force P of the bucket 9 ₁Exceeds the upper limit setting
It is judged that it has not been made and whether it is on the bucket chain line 8
When it is judged that the load exceeds the lower limit setting value (S1
02, S103, S104), the vertical column horizontal transfer
Speed-up instruction to the dynamic system control section 21a, boom boom-and-elevation system control section 2
1b motion instruction or bucket speed system control unit 21c
To increase the speed (see S106). According to this
Direct column traverse movement system control unit 21a, boom elevation system control unit
21b or bucket speed system controller 21c
Speed increase control of the section, increase control of the bite amount of the bucket 9
Control for increasing the moving speed of the bucket or bucket 9 is performed.

The operating conditions, adjustment range and combination of each control when controlling the excavation reaction force P ₁ of the bucket 9 and the load applied to the bucket chain line 8 as described above are determined by the operating method and the capability of each device. , Strength, etc.

The bucket excavation reaction force control unit 19 inputs a detection signal from the pressure detector 18, and when this detection value exceeds the set value, the buffer hydraulic cylinder 15 is supplied as shown in FIG.
To drive the rear guide sprocket 16 upward and tilt the bucket chain line 8 between the guide roll base 7 and the rear guide sprocket 16 to reduce the excavation reaction force P ₁ of the bucket 9.

Therefore, according to the bucket excavating device having the above-described structure, when the bulk load 11 is unloaded in the same manner as the bucket excavating device according to the prior art (see the section of "Prior Art"), the cutting excavation of the bucket 9 is prevented. When the force P ₁ increases and exceeds the upper limit set value, the vertical column lateral movement system control unit 21a, the boom / elevation system control unit 21b, or the bucket speed system control unit 21c responds to an instruction from the bucket load control unit 20. ,
The traverse speed acceleration control of the excavation part, the reduction control of the biting amount of the bucket 9 or the movement speed acceleration control of the bucket 9 is performed,
The excavation reaction force P ₁ of the bucket 9 is reduced. Thus, the excessive excavation reaction force P ₁ of the bucket 9 is prevented, and the abnormal vibration of the vertical column 4 is reliably prevented.

When the load applied to the bucket chain line 8 becomes large or small and deviates from a certain range, the vertical column lateral movement system control unit 21a and the boom / elevation system control unit are instructed according to an instruction from the bucket load control unit 20. 21b or the bucket speed system control unit 21c performs the traverse speed deceleration or acceleration control of the excavation unit, the decrease or increase control of the bite amount of the bucket 9, or the movement speed deceleration or acceleration control of the bucket 9, and the bucket chain line 8 Such load is kept within a certain range. Thus, the fixed amount dispensing operation of the bulk cargo 11 can be realized easily and surely.

Since the bucket excavation reaction force control unit 19 for controlling the buffer hydraulic cylinder 15 is provided, when the excavation reaction force P ₁ of the bucket 9 is normal, the bucket chain line 8 is parallel to the bottom frame 12 as shown in FIG. When the bucket 9 bites into the bulk load 11 and unloading is performed while the digging reaction force P ₁ of the bucket 9 increases and exceeds the set value, the bucket digging reaction force control unit 19 causes the buffer hydraulic pressure to increase. The cylinder 15 is contracted and driven, and the rear guide sprocket 15 moves upward (see FIG. 5), so that the excavation reaction force P _{1 of the} bucket is reduced. Thus, the excessive excavation reaction force P ₁ of the bucket 9 can be prevented, and the abnormal vibration of the vertical column 4 can be reliably prevented. Further, when a strong push-up force acts on the bucket 9 from the floor of the hold or the like at the time of excavating the bottom load and the detected value of the pressure detector 18 exceeds the set value, the rear guide sprocket 16 is operated in the same manner as above. Since it moves upward, the thrust force is absorbed thereby, and the structure can be protected. Further, the bucket excavation reaction force control 19 is used to extend and retract the buffer hydraulic cylinder 15 to thereby expand and contract the bucket chain 9.
The tension of can be maintained. This is particularly effective when the bottom frame 12 has a fixed length without a tension holding cylinder.

[0035] Note that without providing the bucket excavation reaction force control unit 19, may be directly buffer the hydraulic cylinder 15 is contracted when the excavation reaction force P ₁ when the increased drilling reaction force P ₁ of the bucket 9. Even in such a configuration, when the excavation reaction force P ₁ of the bucket 9 becomes large, the excavation reaction force P ₁ causes the buffer hydraulic cylinder 15 to contract and the buffer hydraulic cylinder 15 and the swing arm 13 to swing upward. Since the rear guide sprocket moves upward and the excavation reaction force P ₁ of the bucket 9 is reduced, the excessive excavation reaction force P ₁ of the bucket 9 is prevented and the abnormal vibration of the vertical column 4 is surely generated. Can be prevented. Further, even when a strong push-up force acts on the bucket 9, the rear guide sprocket 16 moves upward and absorbs the push-up force, so that the structure can be protected. Furthermore, the tension of the bucket chain 9 can be maintained by the urging force of the buffer hydraulic cylinder 15.

When the bucket excavation reaction force control unit 19 is not provided, the buffer hydraulic cylinder 15 is provided so as to automatically expand and contract by the excavation reaction force P ₁ of the bucket 9 and the thrust force from the floor of the hold, etc. The buffer hydraulic cylinder 15 when the reaction force control unit 19 is provided is provided so as to operate under the control of the bucket excavation reaction force control unit 19 at a higher pressure than when the bucket excavation reaction force control unit 19 is not provided.

[0037]

As described above in detail with reference to the embodiments, according to the present invention, when the excavation reaction force of the bucket increases, the excavation reaction force causes the cushioning member to contract and the cushioning member and the swing arm to move upward. Rocks to move the guide sprocket upwards, reducing the excavation reaction force of the bucket.
Excessive excavation reaction force of the bucket can be prevented, and abnormal vibration of the vertical column can be reliably prevented. Further, even when a strong push-up force acts on the bucket, the guide sprocket moves upward in the same manner as described above, so that the push-up force is absorbed and the structure can be protected. Furthermore, the tension of the bucket chain can be maintained by the urging force of the buffer member.

Further, since the buffer cylinder is provided as the buffer member, and the pressure detector of this buffer cylinder and the control means for controlling the expansion and contraction of the buffer cylinder according to the detection value of this pressure detector are provided, When the excavation reaction force increases and the detected value of the pressure detector exceeds the set value, the buffer cylinder is contracted and driven by the control means, and along with this, the buffer cylinder and the swing arm swing upward, and the guide sprocket moves upward. Since the excavation reaction force of the bucket is reduced due to the movement, it is possible to prevent the excavation reaction force of the bucket from being excessive, and it is possible to reliably prevent the abnormal vibration of the vertical column portion. Also, when a strong thrust force acts on the bucket and the detected value of the pressure detector exceeds the set value, the guide sprocket moves upward in the same manner as above, so the thrust force is absorbed and the structure is protected. can do.

Further, a cushioning cylinder is provided as a cushioning member, the pressure detector of the cushioning cylinder, the bucket load detector provided on the drive sprocket, and the excavation reaction force of the bucket or the bucket load detector based on the detection values of these detectors. By including the control means for controlling the load applied to the chain line, when the excavation reaction force of the bucket becomes large and the detection value of the pressure detector exceeds the set value, the control means causes
Deceleration control of the traverse speed of the excavation part, reduction control of the biting amount of the bucket by raising operation of the excavation part, or deceleration control of the moving speed of the bucket is performed, and the excavation reaction force of the bucket decreases, so that an excessive bucket Excavation reaction force is prevented from being generated, and abnormal vibration of the vertical column can be surely prevented. Further, by the same control means, the load applied to the bucket chain line is accurately obtained from the difference between the detection value of the bucket load detector and the detection value of the pressure detector, and the traverse speed of the excavating section is kept so as to keep this load within a certain range. Since the control, the bite amount control of the bucket by the raising / lowering operation of the excavating unit, or the speed control of the bucket is performed, the fixed amount dispensing operation of the bulk load can be easily and surely realized.

[Brief description of drawings]

FIG. 1 is a side view showing a bucket excavator of an unloader according to an embodiment of the present invention.

FIG. 2 is an enlarged side view showing the vicinity of a rear guide sprocket in FIG. 1 in an extracted manner.

FIG. 3 is a view taken along the line III-III in FIG.

FIG. 4 is an enlarged side view of the vicinity of the bottom frame extracted from FIG. 1, showing a state during normal operation.

5 is an enlarged side view of the vicinity of the bottom frame extracted from FIG. 1, showing a state during an excessive excavation force avoidance operation. FIG.

6 is a block diagram showing details of the bucket load control unit shown in FIG. 1 and the like.

FIG. 7 is a flowchart showing the processing contents of each part in the bucket load control part shown in FIG.

FIG. 8 is a side view showing a bucket excavator of an unloader according to a conventional technique.

[Explanation of symbols]

1 Suspended boom 2 Parallel link 3 L frame 4 Vertical column 5 Vertical frame 5a Upper mounting shaft 5b Swing hydraulic cylinder 6 Intermediate guide sprocket 7 Drive sprocket 8 Bucket chain line 8a Bucket chain 9 Bucket 10 Bucket load detector, 11 Bulk load 12 Bottom frame 12a Connection shaft 12b Swing cylinder 13 Swing arm 14 Swing arm 14 Arm mounting shaft 15 Buffer hydraulic cylinder 15a Cylinder mounting shaft 16 Rear guide sprocket 16a Rotating shaft 17 Guide roll base 17a Roller 18 Pressure detector 19 Bucket excavation reaction force control unit 20 Bucket load control unit 20a Calculation unit 20b Load determination unit 20c Control instructing unit 21a Vertical column lateral movement system control unit 21b Boom and elevation system control unit 21c Bucket speed system control unit P ₁ Excavation reaction force

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Kimoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Prefecture Mitsubishi Heavy Industries Hiroshima Works

Claims (3)

[Claims] 1. A bucket chain line, comprising a bucket chain and a bucket attached to the bucket chain, is circulated along a vertical column and a frame provided at the lower end of the vertical column driven by a drive sprocket. A bucket excavating device for an unloader having a constructed excavating portion, wherein the excavating portion is disposed so as to be occupied at a lower end portion of the excavating portion and a downstream end portion in a moving direction of the bucket chain line, and engages with the bucket chain. A guide sprocket for guiding the bucket chain in the direction of the vertical column, and a base end portion of which is swingably supported by the frame,
A swing arm that rotatably supports the guide sprocket at the tip portion, and a base end portion that is swingably supported by the frame,
A bucket excavating device for an unloader, comprising: a shock-absorbing member whose distal end is located downstream of the base end in the moving direction of the bucket chain line and which is connected to the guide sprocket. 2. The bucket excavating device for an unloader according to claim 1, wherein the buffer member is a buffer cylinder, and the pressure detector of the buffer cylinder and expansion / contraction of the buffer cylinder based on a detection value of the pressure detector. Controlling means for controlling the excavation reaction force of the bucket by controlling the bucket excavation device of the unloader. 3. The bucket excavating device for an unloader according to claim 1, wherein the buffer member is a buffer cylinder, a pressure detector of the buffer cylinder, a bucket load detector provided on the drive sprocket, and both of these detectors. And a control means for controlling the excavation reaction force of the bucket or the load applied to the bucket chain line by controlling the traverse speed of the excavation section, the biting amount of the bucket or the moving speed of the bucket based on the detection value of the excavator. An unloader bucket excavator.