JP4260279B2 - Continuous unloader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a continuous unloader for continuously unloading bulky pieces and easily loose pieces in a hold.
[0002]
[Prior art]
In general, a continuous unloader is used to continuously scrape and unload loose pieces in a hold with a large number of buckets attached to the unloader body, which is a rigid body. When handling loose objects that tend to harden due to moisture or pressure during voyage, if the ship is shaken and lifted during the scraping operation due to the influence of waves or a navigating ship, the bucket is pressed against the surface of the hard loose objects. There was a problem that the scraping part was damaged.
[0003]
As means for preventing an overload that acts on an unloader from a loose article during cargo handling, for example, methods such as Japanese Utility Model Publication No. 62-34909, Japanese Patent Application Laid-Open No. 7-48037, Japanese Utility Model Publication No. 4-32336 have been proposed. Yes.
[0004]
[Problems to be solved by the invention]
In Japanese Utility Model Publication No. 62-34909, the relief pressure of the boom hoisting cylinder is switched to the low pressure side during work, and when an upward load is applied to the excavation part, the entire boom is released upward, and the overload caused by pushing up the ship is overloaded. I try to prevent it.
[0005]
However, when the weight of the scraping part is large, there is a problem that the load acting on the bucket becomes too large. Also, if the ship descends after upswing, if the push-up force decreases and the relief valve closes, the scraping part will maintain the maximum ascending position, and it will not be able to continue scraping, or the surface will be scraped slightly. There will be no. As a result, when the ship frequently moves up and down, the continuity of cargo handling cannot be maintained, and there is a problem that the cargo handling efficiency is remarkably lowered.
[0006]
Japanese Patent Application Laid-Open No. 7-48037 detects a load acting on the scraping tip, and if this exceeds a certain value, the scraping portion is raised to avoid overload. It reacts to the overload acting on the part, but has no effect on the push-up force acting on the bucket bottom from the rose.
[0007]
In Japanese Utility Model Publication No. 4-32336, a spring and a limit switch are incorporated in the upper part of a bucket elevator, and when an excessive lateral load is applied, the limit switch is activated to stop further movement. Similar to that of Kaihei 7-48037, it is ineffective for upward push-up force from a rose.
[0008]
In the bucket elevator type continuous unloader, the bucket is protected from damage by controlling excessive push-up force acting on the bottom of the bucket by the lump or solid rose surface when the ship rises, and the scraping trajectory is made as flat as possible. It is intended to provide a continuous unloader that keeps the surface of the excavated surface to a minimum and prevents a decrease in cargo handling efficiency.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a continuous unloader according to the present invention has an L-shaped scraping portion attached to a swing arm that can be rotated by a hydraulic cylinder at a lower portion of a vertical elevator, and the load cell provided in the scraping portion. Detects the load between the bucket and the scraping frame, and controls the hydraulic cylinder pressure based on the detected load to limit the load on the scraping section. A sensor for inputting the length to the control device is provided, and the control device is
[0010]
(A) During normal excavation, when the downward load of the load cell decreases from a preset threshold value, the hydraulic circuit of the hydraulic cylinder is switched from the operation mode to the overload avoidance mode, and at the same time, the stroke length of the hydraulic cylinder at that time is stored.
(B) During the overload avoidance mode, if the stroke length of the hydraulic cylinder is equal to or less than the stored initial stroke length, the overload avoidance mode is continued. If the initial stroke length is exceeded, the overload avoidance mode is switched to the operation mode. It is characterized by comprising.
[0011]
According to such a configuration, when the ship flies up and down while unloading a loose article having a hard surface, the scraping portion avoids upward, so that the bucket and the unloader body are not damaged.
[0012]
In addition, the level of the scraping part before the control device switches from the operation mode to the overload avoidance mode is memorized and controlled so that it does not fall below that level. Will not drop past the initial level.
Therefore, excessive irregularities are generated on the surface of the rose, and subsequent work is not hindered.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 4, the unloader body 1 that is provided on a travelable machine base 51 that can be swung and raised is provided with a vertical elevator section 4 at its tip. The unloader scraping section 3 (hereinafter referred to as scraping section 3) provided in the vertical elevator section 4 continuously unloads the loose objects 9 in the hold 2a of the ship 2.
[0014]
As shown in FIG. 1, the scraper 3 mainly includes a large number of buckets 5 attached to an endless chain 13 at regular intervals, a swing arm 6, a swing cylinder 7, a tilt cylinder 8, and spckets 15 and 16 at both front and rear ends. The chain 13 is stretched over drive sprockets (not shown) provided on the tops of the front and rear spckets 15 and 16 and the vertical elevator 4.
[0015]
The swing arm 6 and the scraping frame 31 are supported in an L shape by a swing cylinder 7 bridged between the vertical elevator unit 4 and the swing arm 6. The scraping frame 31 is tilted by a tilt cylinder 8 bridged between the frame 31 and a tilt arm 32 parallel to the swing arm 6.
As shown in FIG. 1, the swing cylinder 7 includes a swing cylinder hydraulic circuit 19, and the tilt cylinder 8 includes a tilt cylinder hydraulic circuit 20.
[0016]
The head side hydraulic line 25 and the rod side hydraulic line 26 in the swing cylinder hydraulic circuit 19 are connected to the hydraulic pump 18 via the direction switching valve 24. In addition, the float valve 22 is provided in the branch line 33 branched from the head side hydraulic line 25, and the float valve 21 is connected to the bypass line 35 connected to the rod side hydraulic line 26 and the distribution line 34 on the outlet side of the hydraulic pump 18. And an electromagnetic proportional pressure control valve 23 in order.
[0017]
As shown in FIGS. 2 and 3, the guide roller 11 attached to the bucket 5 is engaged with the guide rail 11 suspended via the connecting member 36 below the scraping frame 31. , Load cells 14a and 14b are provided. Then, the weight of the bucket and the weight of the scraped pieces are input to the control device 17 from these load cells 14a and 14b. Further, the stroke length of the swing cylinder 6 is input to the control device 17 from a stroke sensor 37 provided in the swing cylinder 6.
[0018]
On the other hand, the threshold value (the weight of the bucket and the set weight of scraped pieces, etc.) is input to the control device 17 in advance, and the downward load of the load cells 14a, 14b is the value of the threshold value set in advance. When it further decreases, the operation mode is automatically switched to the overload avoidance mode, and the float valves 21 and 22 are switched from the closed position to the open position. At the same time, the stroke length of the swing cylinder 7 at that time, that is, the initial stroke length Is to be remembered.
[0019]
Further, during the overload avoidance mode operation, the control device 17 continues the overload avoidance mode if the stroke length of the swing cylinder 7 is equal to or less than the stored initial stroke length, and from the overload avoidance mode when the initial stroke length is exceeded. A function to automatically switch to the operation mode is provided.
[0020]
As shown in FIG. 6, in normal cargo handling, the bucket elevator hoisting device (not shown) and the swing cylinder 7 are operated, and the scraping portion 3 is bitten by a certain depth D from the surface of the loose article 9. The posture is fixed with, and the rose 9 is scraped off by the lateral movement of the unloader. In this state, the float valves 21 and 22 and the direction switching valve 24 of the swing cylinder hydraulic circuit 19 are all in the closed position, the pressure oil to the swing cylinder 7 is shut off, and the swing cylinder 7 is in the fixed position. Is held (S ₁ ).
[0021]
However, when the vessel 2 rises and an upward reaction force acts on the bucket 5, the total value of the detection values of the load cells 14a and 14b decreases from the threshold value.
That is,
Total value of load cell detection value <threshold value (1)
(S ₂ ), the operation mode is automatically switched to the overload avoidance mode. Then, the float valves 21 and 22 are switched from the valve closing position to the valve opening position according to a command from the control device 17 (S ₃ ), and at the same time, the electromagnetic wave is set so that the total value of the load cells 14 a and 14 b becomes a preset threshold value. The proportional pressure control valve 23 is controlled.
[0022]
Then, pressure oil whose pressure is controlled by the electromagnetic proportional pressure control valve 23 acts on the rod side of the swing cylinder 7, and the scraping unit 3 has an upward force generated by the cylinder force and the weight of the scraping unit 3. The resultant force of the downward load due to the weight of the scraped piece is applied. The load between the bucket 5 and the surface of the loose article is controlled thereby (S ₄ ), and thereafter the scraping portion 3 avoids upward according to the magnitude of the pressing force from the loose article 9.
[0023]
Further, since the control device 17 stores the initial stroke length of the swing cylinder 7 when the float valves 21 and 22 are switched from the valve closing position to the valve opening position (S ₅ ), the lifting force of the loose article 9 is reduced. When the swing arm 6 is lowered and the swing cylinder 7 is extended to the stored initial stroke length (S ₆ ), the overload avoidance mode is automatically switched to the operation mode, and the float valves 21 and 22 are opened. To the valve closing position (S ₇ ).
[0024]
Accordingly, when the ship 2 is lifted and the pushing force from the loose article 9 becomes excessive, the scraping portion 3 is lifted by a height H avoiding overload (see FIG. 7), and the ship 2 is lowered or separated. When the surface of the object 9 changes softly and the push-up force decreases, the scraping portion 3 does not descend below the original height level (see FIG. 8). For this reason, the surface of the scraped material 9 that has been scraped off can maintain a flat surface except for a portion that has been raised to avoid overload.
[0025]
On the other hand, the tilt cylinder 8 is a device for changing the inclination of the scraping unit 3, and by controlling the pressure of the tilt cylinder 8 at the bottom preparation stage where the bucket 5 of the scraping unit 3 contacts the ship bottom. It acts to bring the bucket row into contact with the ship bottom evenly. Since the tilt cylinder hydraulic circuit 20 connected to the tilt cylinder 8 has the same configuration and function as the swing cylinder hydraulic circuit 19 connected to the swing arm cylinder 7, detailed description thereof is omitted. However, in the overload avoidance mode, each valve on the tilt cylinder hydraulic circuit 20 side remains in the normal excavation position in order to prevent the surface to be excavated from inclining.
[0026]
【The invention's effect】
As described above, according to the present invention, the bucket and the unloader main body are not damaged even when the ship fluctuates and floats while unloading a rose having a hard surface.
Also, since the control device memorizes the height position (level) before switching from the operation mode to the overload avoidance mode, and the control device controls so that it does not fall below that, when the ship descends after shaking up However, the excavation bucket does not descend beyond the initial level.
[0027]
Therefore, excessive irregularities are generated on the surface of the rose, and subsequent work is not hindered. In particular, when the variation in the surface hardness of loose objects is large, or when there is no function of the present invention, the scraped part sinks in the soft part, resulting in irregularities on the surface to be excavated, which adversely affects the subsequent work. It will be.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram applied to a continuous unloader of the present invention.
FIG. 2 is a side view of a scraping portion.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is a side view of a continuous unloader during cargo handling.
FIG. 5 is a control flow diagram.
FIG. 6 is an explanatory view showing a normal excavation position of the scraping portion.
FIG. 7 is an explanatory view showing the position of a scraping portion when the ship is raised by a height H;
FIG. 8 is an explanatory diagram showing the position of the scraping portion when the ship descends from its original position.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 Scraping part 4 Vertical elevator part 6 Swing arm 7 Hydraulic cylinder 14a, 14b Load cell 17 Control apparatus 19 Hydraulic circuit 37 Sensor

Claims (1)

At the lower part of the vertical elevator, there is an L-shaped scraping part attached to a swing arm that can be rotated by a hydraulic cylinder, and the load between the bucket and the scraping frame is detected by a load cell provided in the scraping part. A bucket elevator type continuous unloader provided with a control device for limiting the load of the scraping part by controlling the pressure of the hydraulic cylinder by the load is provided with a sensor for inputting the stroke length of the hydraulic cylinder to the control device, and the control device The
(A) During normal excavation, when the downward load of the load cell decreases from a preset threshold value, the hydraulic circuit of the hydraulic cylinder is switched from the operation mode to the overload avoidance mode, and at the same time, the stroke length of the hydraulic cylinder at that time is stored.
(B) During the overload avoidance mode, if the stroke length of the hydraulic cylinder is equal to or less than the stored initial stroke length, the overload avoidance mode is continued. If the initial stroke length is exceeded, the overload avoidance mode is switched to the operation mode. A continuous unloader characterized by comprising.

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