Cargo handling machinery and operation method thereof

Abstract

To provide a cargo handling machine and an operation method of the cargo handling machine capable of detecting or preventing overload operation in a simple manner.SOLUTION: A cargo handling machine includes: a boom 3 used for at least one of delivery and loading of bulk materials; a load measuring device 6 provided on a fulcrum part of the boom 3 for measuring at least a load of the boom 3; and a control device for monitoring whether the overload occurs at least on the boom 3 based on a measured result of the load measuring device 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a loading machine and an operating method for the loading machine. [Background technology]

[0002] Loading and unloading machines (raw material transport equipment) that discharge and stack bulk raw materials (bulk materials) include reclaimers, stackers, stack reclaimers, etc. When using such loading and unloading machines in steelworks, they handle large amounts of highly corrosive raw materials for steelmaking, and many of them are installed in outdoor environments near the coastal areas of the factories, which, combined with the aging of the equipment, has led to the occurrence of collapse accidents and similar damage problems.

[0003] The main cause of these problems is a decrease in strength due to corrosion and fatigue cracks in the main strength components. Iron-making raw materials such as iron ore and coal tend to accumulate on the structures and bucket wheels of loading and unloading machines, and when they absorb moisture such as rainwater, they become more adhesive and tend to accumulate even more. This accumulated raw materials promotes corrosion of the steel structures. In addition, the weight of the machine increases due to the accumulated raw materials, which places excessive loads on the structures. Continuing to operate under excessive loads for a long period of time will eventually cause fatigue cracks in the metal. When corrosion reduces the thickness of components, the stress generated in each component increases, increasing the risk of collapse failure such as fatigue cracks and buckling of the structure.

[0004] Anticorrosive coating is used as a corrosion prevention measure. To prevent overload operation, a structure with a buffer function in the wheel power transmission path (e.g., Patent Document 1) and a structure to prevent accumulation of raw materials (e.g., Patent Document 2) have been devised. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-20819 A [Patent Document 2] JP 2000-289856 A Summary of the Invention [Problem to be solved by the invention]

[0006] As in Patent Document 1, a structure having a buffer function in the wheel transmission path is useful for preventing excessive loads that occur accidentally during excavation, but it has the problem that it cannot prevent excessive loads that occur when raw materials are piled up in the structure. In addition, the structure of Patent Document 2, which uses steel pipes in the structure to prevent the accumulation of raw materials, is fundamentally different in structure from existing loading and unloading machinery such as reclaimers, stackers, and stack reclaimers. Therefore, although it may be possible to introduce it in new construction, there was an issue that it could not be applied to existing loading and unloading machinery. Furthermore, it was uneconomical to design strength members with a large corrosion allowance (higher safety factor for allowable stress) in order to prevent corrosion and fatigue cracks. Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a loading machine and an operating method for a loading machine that can easily detect or prevent overload operation. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a loading and unloading machine comprising a boom used for at least one of discharging and loading bulk raw materials, a load measuring device at a fulcrum of the boom for measuring at least the load of the boom, and a control device for monitoring whether or not an overload has occurred at least on the boom based on a measurement result of the load measuring device. According to one aspect of the present invention, there is provided a method for operating a loading machine, which measures a load on a fulcrum of a boom used for at least one of discharging and loading bulk materials, and monitors whether or not an overload has occurred on at least the boom based on the result of the load measurement. Effect of the Invention

[0008] According to one aspect of the present invention, there is provided a loading machine and an operating method for the loading machine that can simply detect or prevent overload operation. [Brief description of the drawings]

[0009] [Figure 1] 1 is a configuration diagram showing a loading machine according to an embodiment of the present invention. [Diagram 2] 1 is a graph showing the relationship between undulation height and cylinder load. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the following detailed description, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, identical or similar parts are given identical or similar symbols, and duplicated explanations are omitted. Each drawing is schematic and may differ from the actual one. In addition, the embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, structures, arrangements, etc. of the components as described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the claims.

[0011] A loading / unloading machine according to an embodiment of the present invention is a reclaimer that discharges bulk raw materials. For example, the reclaimer discharges iron ore, coal, and the like, which are raw materials for steelmaking, in a steelworks. In discharging, for example, the reclaimer excavates the bulk raw materials piled up in a yard and transports them to the next process.

[0012] As shown in Fig. 1, the cargo handling machine 1 includes a bucket wheel 2, a boom 3, an internal conveyor 4, a derrick cylinder 5, a load measuring device 6, a counterweight 7, an internal chute 8, a traveling device 9, an external conveyor 10, a cab 11, a swivel device 12, and a frame connection section 13. The boom 3 is used for at least one of discharging and stacking bulk materials, and in the case of a reclaimer, it is used for discharging bulk materials. The cargo handling machine 1 also includes a control device (not shown) that judges overload according to the measurement results of the load measuring device 6 in a monitoring process described later and controls the cargo handling machine 1 in accordance with this judgment. The control device is provided inside the cab 11 or the like or outside the cargo handling machine 1, and is composed of, for example, a computer, a PLC, or the like.

[0013] In the operating method of the cargo handling machine 1, the bucket wheel 2 provided at one end of the boom 3 is moved to a predetermined excavation position by the traveling operation by the traveling device 9, the rotating operation of the boom 3 by the swivel device 12, and the raising and lowering operation of the boom 3 by the hoisting cylinder 5 (moving process). The traveling device 9 is a self-propelled wheel or the like, and is connected to the reclaimer body via a frame connecting part 13. In the hoisting operation, the boom 3 is raised and lowered to adjust the height of the bucket wheel 2 (also called the hoisting height). The hoisting height is the height of the bucket wheel 2 from the ground surface, the vertical height of the bucket wheel 2 based on the state in which the boom 3 is in a horizontal position, etc., and can be set appropriately.

[0014] After the moving step, the cargo handling machine 1 rotates the bucket wheel 2 to scrape off the bulk materials piled up in the yard, thereby excavating (excavation step). The bulk materials scraped off by the bucket wheel 2 are transported to an internal chute 8 by an internal conveyor 4 provided along a boom 3. The bulk materials are then supplied from the internal chute 8 to an external conveyor 10, which transports them to the next step. Note that in the excavation step, at least one of the traveling operation, the turning operation, and the raising and lowering operation described above may be performed in parallel with the collection of the bulk materials by the bucket wheel 2.

[0015] Furthermore, in this embodiment, the control device monitors the load of the cargo handling machine 1 based on the measurement results of the load measuring device 6 (monitoring process). In the load monitoring, whether or not an overload occurs on at least the boom 3 is monitored based on the measurement results of the load measuring device 6. The load measuring device 6 is provided at the boom fulcrum portion which serves as the fulcrum of the boom 3, and measures the load applied to the boom 3 and the bucket wheel 2, and is, for example, a load cell. In the example shown in FIG. 1, the load measuring device 6 is provided at the other end side of the boom 3 where the counterweight 7 is provided, and at the lower end of the hoisting cylinder 5. The load cell is not particularly limited as long as it can measure the load applied at the fulcrum portion of the boom 3, and may be, for example, disposed at the connection portion with the hoisting cylinder 5 at the base of the boom 3. Also, a pin-type load cell may be used, and the pin-type load cell may be provided at the mounting pin portion of the hoisting cylinder 5. In the example shown in FIG. 1, the load measured by the load measuring device 6 is also referred to as a cylinder load. The monitoring process is performed in parallel with the excavation process, and the cylinder load applied to the boom 3 during excavation is measured.

[0016] The load measuring device 6 also measures the weight increase of the boom and bucket wheel due to the accumulation of bulk raw materials (also called raw material pile). In the loading machine 1, when bulk raw materials are spilled during the excavation process, raw material piles up on the frame of the boom 3 and the side of the bucket wheel 2, and the weight of the boom 3 and bucket wheel 2 increases, resulting in a load.

[0017] In the monitoring process, the control device judges whether or not the load on the cargo handling machine 1 is overloaded based on the applied load measured by the load measuring device 6. The overload judgment is performed using a threshold value obtained from the relationship between the applied load and the elevation height.

[0018] For example, overload can be determined based on the graph shown in Fig. 2. The graph shown in Fig. 2 shows the relationship between the hoisting height [m] and the cylinder load [tf (metric ton-force)] measured by the load measuring device 6. The cylinder load also changes depending on the hoisting height, and in the case of the cargo handling machine 1 shown in Fig. 1, the cylinder load decreases as the cylinder height increases, and the cylinder load and the hoisting height have a linear relationship as shown in Fig. 2.

[0019] In FIG. 2, the line D1 indicates the relationship between the undulation height and the cylinder load when there is no raw material pile and no excavation load. The line D2 indicates the relationship between the undulation height and the cylinder load when there is an allowable upper limit weight increase due to raw material pile and there is no excavation load. The line D3 indicates the relationship between the undulation height and the cylinder load when there is an allowable upper limit weight increase due to raw material pile and the discharge is performed at maximum capacity (when the excavation load is maximum). The excavation load is a load according to the excavation speed (mainly the rotation speed of the bucket wheel 2) and is a load according to the weight of the bulk raw material inside the bucket wheel 2 and on the internal conveyor 4. The applied load due to the allowable upper limit weight increase due to raw material pile is also called the maximum raw material pile load. In other words, the line D3 can be obtained by adding up the maximum raw material pile load and the maximum excavation load at each undulation height.

[0020] In other words, the cylinder load indicated by line D1 is the load due only to the weight of the machine body such as the boom 3 and bucket wheel 2, and if there are no abnormalities in the equipment or load measuring device 6, it will be the lower limit of the cylinder load measured by the load measuring device 6. If the measured cylinder load is less than the cylinder load of line D1, there is a possibility that the load is being applied from an unexpected direction. For this reason, when judging an overload, if the measured cylinder load is less than the cylinder load of line D1 at the same elevation height (overload range in Figure 2), it is judged to be an overload.

[0021] The maximum raw material pile load is taken into consideration when designing the machine, and is specified, for example, in ISO 5049 / 1. That is, the cylinder load indicated by the line D3 is the upper limit of the cylinder load that the cargo handling machine 1 can tolerate, and if the measured cylinder load exceeds the line D3 (the overload region in FIG. 2), it is determined to be overloaded. Also, the line D3, which is the upper limit of the cylinder load, may be set as a value at which the stress generated in each part of the structure of the cargo handling machine 1 due to the applied load caused by at least an increase in the weight of the boom 3 is equal to or lower than the fatigue limit.

[0022] Here, as a past knowledge, troubles such as the machine body floating up or the structural frame deforming or buckling occurred due to the load increase caused by the accumulation of raw materials on the boom 3 and bucket wheel 2. Since existing reclaimers cannot detect the load increase caused by the accumulation of raw materials on the boom 3 and bucket wheel 2, the load increase is only recognized when the capacity limit of the hoisting device such as the hoisting cylinder 5 is reached (motor trip, etc.), and measures such as cleaning are taken. The load on the reclaimer structure is dominated by the excavation force generated when the bucket wheel 2 discharges bulk raw materials and the weight increase due to the accumulation of raw materials on the side of the bucket wheel 2 and the frame of the boom 3. This is because the load on the bucket wheel 2 and the boom 3 generates a large bending moment because the point of application of the force is away from the center of the machine. Therefore, the load on the reclaimer structure can be accurately grasped by measuring the load on the fulcrum of the boom 3.

[0023] That is, in the monitoring process, the cylinder load during the excavation process is measured, and by determining overload using line D3 as the upper limit of the cylinder load, it is possible to detect abnormalities caused by the accumulation of raw materials before the above-mentioned trouble occurs. The limiting factor in the lifespan of a reclaimer is damage to the structure, such as cracks and deformation. Normally, this structure is designed not to cause metal fatigue, that is, so that the stress generated in each part for the expected load is below the fatigue limit. If it becomes possible to prevent unexpected loads, it will be possible to significantly extend the lifespan of the structure.

[0024] As described above, in this embodiment, the cargo handling machine 1 is used so that the cylinder load according to the elevation height is between the straight lines D1 and D3 shown in FIG. 2. In the monitoring process, when the overload is judged to be overloaded, that is, when it is judged that the amount of raw materials accumulated exceeds the allowable amount, the cargo handling machine 1 in operation may be stopped in an emergency manner by an interlock or the like. When the overload is judged to be overloaded, an alarm or a display may be issued to notify the operator of the overloaded state. In this way, overload operation can be easily prevented. Therefore, the machine body can be protected from overload and fatigue cracks and deformation / buckling of the structure can be prevented, so that the service life of the cargo handling machine 1 can be significantly improved.

[0025] Furthermore, when the measured cylinder load is a value between the lines D1 and D2 in FIG. 2, the stress on the structure is within the allowable range, that is, the normal use range, and the load increase due to the accumulation of raw materials is also small, so there is no need to limit the machine operation. However, when the measured cylinder load is a value between the lines D2 and D3, the cylinder load between the lines D2 and D3 (alarm range in FIG. 2) is within the normal use range, so there is no risk of machine damage, but depending on the cutting load, the load increase due to the accumulation of raw materials may exceed the allowable value. For this reason, an alarm or display may be issued to the operator that the cylinder load is in the alarm range. Also, the alarm or display may be issued when the loading machine 1 is stopped. In this way, the operator can recognize that cleaning is necessary, and it can be used as a guide for cleaning.

[0026] That is, when determining whether an overload occurs based on the cylinder load, the relationship between the cylinder load and the undulation height, which is the upper and lower limits of the overload, is obtained in advance (for example, a linear formula as shown in FIG. 2 or a separately set table, etc.), and the occurrence of an overload can be detected by using this relationship as a threshold value to determine whether an overload has occurred. From the viewpoint of only detecting the occurrence of an overload due to raw material accumulation, it is also possible to make the determination using only the upper limit value indicated by line D3. Furthermore, by obtaining the relationship of line D2 (the relationship between the undulation height and the cylinder load in the absence of an excavation load in a state where there is an allowable upper limit amount of weight increase due to raw material accumulation) in advance, and further using this relationship as a threshold value, it is possible to determine whether the amount of raw material accumulation is large. The monitoring step is preferably performed continuously while the excavation step is being performed, thereby making it possible to constantly monitor for the occurrence of overload.

[0027] <Modification> Although the present invention has been described above with reference to specific embodiments, it is not intended that the invention be limited by these descriptions. By referring to the description of the present invention, other embodiments of the present invention including various modifications in addition to the disclosed embodiments will be apparent to those skilled in the art. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments including these modifications described herein, either alone or in combination.

[0028] For example, in the above embodiment, the cargo handling machine 1 is a reclaimer, but the present invention is not limited to such an example. The cargo handling machine 1 is not limited to such an example as long as it is equipped with a boom 3 and generates a raw material pile on the boom 3. For example, the cargo handling machine 1 may be a stacker that has a boom 3 and stacks bulk raw materials, or a stack reclaimer that has both the functions of a reclaimer and a stacker.

[0029] In the above embodiment, the load measuring device 6 measures the cylinder load, but the present invention is not limited to this example. The load measuring device 6 may be any device capable of measuring at least the weight increase and strain of the boom 3. The device configuration and installation position are not limited to the above embodiment. For example, the load measuring device 6 may be a strain gauge that measures the strain of the fulcrum of the boom 3. In this case, the load can be obtained from the measured strain to determine overload as in the above embodiment. In addition, when determining overload from strain, as described later, the measured strain can be used for the determination. Note that the strain gauge can be easily attached to existing cargo handling machines 1, so the present invention can be widely applied.

[0030] Furthermore, in the above embodiment, the overload is judged according to the measured cylinder load, but the present invention is not limited to such an example. The overload may be judged according to a load other than the cylinder load, or according to other indicators such as strain. The load used to judge the overload may be at least equivalent to the load of the boom 3. In addition, if the measured load does not affect the elevation height, a threshold value for the load may be set uniformly regardless of the elevation height. For example, the load measuring device 6 may be installed at a position where the load of a part of the cargo handling machine 1 including the boom 3 can be measured, or may be installed on the frame connecting portion 13 that connects the traveling device 9 to the machine frame. By installing the load measuring device 6 on the frame connecting portion 13, all loads applied to the machine can be monitored.

[0031] Furthermore, in the above embodiment, the monitoring process is performed in parallel with the excavation process, but the present invention is not limited to this example. The monitoring process may be performed during the moving process or when the loading machine 1 is in a non-operating state. In this case, the applied load without the excavation load is measured, and the applied load due to the accumulation of raw materials is known. For example, in the case where the cylinder load and the undulation height have the relationship shown in FIG. 2, if the measured cylinder load is a value between the line D1 and the line D2, the amount of accumulated raw materials is acceptable, and therefore, the bulk raw materials can be discharged in a normal state where the upper limit of the excavation speed is the maximum excavation speed. However, if the cylinder load is a value higher than the line D2, the bulk raw materials can be prevented from being discharged by taking measures such as cleaning without dispensing, or by taking measures to set the upper limit of the excavation speed lower than the maximum excavation speed.

[0032] Furthermore, in the above embodiment, the allowable upper limit weight increase due to the accumulation of raw materials is specified by ISO 5049 / 1, etc., but the present invention is not limited to such an example. The allowable upper limit weight increase due to the accumulation of raw materials may be set individually for each cargo handling machine 1, taking into consideration economic efficiency and the usage environment. [Explanation of symbols]

[0033] 1. Cargo handling machinery 2 Bucket Wheels 3. Boom 4. In-machine conveyor 5. Dinghy cylinder 6 Load measuring device 7 Counterweight 8. In-flight Shootout 9 Running gear 10 External conveyor 11. Cab 12 Swivel 13 Frame connection

Claims

1. a boom for use in at least one of discharging and loading bulk materials; a load measuring device for measuring at least the load of the boom at a fulcrum portion of the boom; a control device that monitors whether or not an overload is occurring on at least the boom based on a measurement result of the load measuring device; Equipped with The load measuring device measures at least the load of the boom as the load, The control device determines that an overload has occurred when the applied load measured by the load measuring device is greater than a preset threshold value, The threshold value is a value according to the elevation height of the boom, and is set as the sum of the maximum raw material pile load, which is the load due to the allowable upper limit weight increase due to raw material pileup, and the maximum excavation load, which is the load when the excavation load is at its maximum, in a loading machine.

2. The cargo handling machine according to claim 1 , wherein the threshold value is set as a value at which a stress generated in each part of the structure by the applied load is equal to or lower than a fatigue limit.

3. The cargo handling machine according to claim 1 or 2, wherein the control device brings the cargo handling machine in an operating state to an emergency stop when it is determined that an overload has occurred.

4. The cargo handling machine according to any one of claims 1 to 3, wherein the load measuring device is a load cell or a strain gauge.

5. The cargo handling machine according to any one of claims 1 to 4, which is a reclaimer, a stacker or a stack reclaimer.

6. measuring a load at a support portion of a boom used for at least one of discharging and loading bulk materials; monitoring whether or not an overload occurs on at least the boom based on the load measurement result; When measuring the load, at least a load weight of the boom is measured as the load, When monitoring whether or not the overload has occurred, it is determined that an overload has occurred if the measured applied load is greater than a preset threshold value; A method for operating a loading and unloading machine, wherein the threshold value is a value according to the elevation height of the boom and is set as the sum of a maximum raw material pile load, which is the load due to the allowable upper limit weight increase due to raw material pileup, and a maximum excavation load, which is the load when the excavation load is at its maximum.

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