JPS5939016B2 - Grab bucket control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling the amount of grasping of a grab bucket, and more particularly to a method and apparatus for controlling the amount of grasping of a grab bucket for picking up loose materials such as coal, ore, and gravel.

Generally, when loading and unloading bulk materials such as coal, ore, and gravel from a ship or the like, a grab bucket as shown in FIG. 1 is used.

As shown in the figure, the grab bucket 2 has two symmetrical shells 2a.

2b, each shell 2a j 2b has a joint 4
It is rotatably joined at.

One end of an opening/closing rope 6 is connected to the joint portion 4 .

Moreover, one end of a shell hanging rope 3 at 3 b is connected to the bottom surface of each shell 2 at 2 b, and the other end of the shell hanging rope 3 at 3 b is connected to the support member 8.

One end of a support rope 10 is connected to the support member 8 .

The other end of the opening/closing rope 6 is wound around an opening/closing drum 16 connected to the rotating shaft of an opening/closing motor 14 via a roller 12 .

The other end of the support rope 10 is wound around a support drum 22 connected to a rotating shaft of a support motor 20 via a roller 18 .

The operation of such a grab bucket will be explained.

The opening/closing operation of the grab bucket is performed by driving the opening/closing drum 16 with the opening/closing motor 14 to wind up and unwind the opening/closing rope 6.

Moreover, when the opening/closing rope 6-way support rope 10 is wound up and unwound at a constant speed, the grab bucket moves up and down with its mouth closed or with its mouth open.

For such grab buckets, the rated load is usually determined, so from the perspective of equipment protection, it is necessary to control the gripping amount (hoisting load) of the grab bucket so that the gripping amount does not exceed the rated load. arise.

Conventionally, the following two methods have been adopted to control the amount of grab by such a grab bucket.

One of them is to adjust the baffle plate of the grab bucket according to the characteristics of the loose material, such as particle size, moisture content, etc.
This is a method of controlling the amount of one grab of the grab bucket so that it does not exceed the rated load.

However, when using this method, the variation in the amount of one grab of the grab bucket increases, so from the knowledge of equipment protection, the baffle plate is adjusted so that the amount of one grab is less than the rated load, which improves cargo handling efficiency. There is a problem in that the value decreases.

In addition, the average grip amount per grab is calculated from the detected value of the crane's in-machine belt wear and the number of reciprocations of the grab bucket, and if the grab amount exceeds the rated load, the grab This is a method of controlling the grasping amount by adjusting the slack length of the support rope at the time when the bucket grabs the loose object, that is, when the grab bucket is closed.

However, when using this method, the driver calculates the average gripping amount and then manually operates the sinking amount adjuster based on this to adjust the slack length of the support rope. It is not possible to grasp the exact amount of grip per grip, and as a result, the amount of sinking and the rated load do not necessarily match, and the amount of grip may exceed the rated load.
There is a problem.

The present invention has been made to solve the above-mentioned problems, and a first object thereof is to provide a grab bucket control method that improves equipment protection and cargo handling efficiency.

A second object of the present invention is to provide a device for implementing a grab bucket control method.

A first object of the present invention is to control the gripping amount of a grab bucket that reciprocates while being supported by a support rope wound by a support motor, and is opened and closed by winding or unwinding the opening/closing rope by the opening/closing motor. , after grasping an arbitrary amount, detecting at least one of the current value of the opening/closing motor and the current value of the support motor, and grasping the packet determined from the detected current value or the detected current value. Compare the amount with a predetermined target set value,
Based on the comparison results, when the amount of grab is small, the slack length of the support rope at the next grab is lengthened, and when the amount of grab is large, the slack length is determined to be shortened to adjust the sinking amount of the grab bucket. This is achieved by the first invention.

A second object of the present invention is to provide an opening/closing motor that opens and closes the grab bucket by winding up or unwinding the opening/closing rope, and a support motor that can reciprocate the grab bucket up and down by winding or unwinding the support rope. a current detector that detects the current value of at least one of the above, a gripping amount calculator that calculates the gripping amount of the grab bucket from the current value detected by the current detector, and a gripping amount calculator that calculates the gripping amount of the grab bucket from the current value detected by the current detector; Based on the signal from the comparator, the comparator compares the gripping amount and the preset setting value, and when the gripping amount is small, the slack length of the support rope at the next gripping becomes longer, and the gripping a sinking amount calculator that calculates the sinking amount of the grab bucket so that the length of the slack becomes short when the amount of slack is large; and a support motor control device that controls the support motor based on the calculation result of the sinking amount calculator. According to a second aspect of the present invention, the present invention includes:

The invention of cylinder 1 will be explained below.

The present invention calculates the gripping amount of the grab bucket from the current value of the motor, and based on this gripping amount, determines the slack length of the support rope during the next gripping to adjust the sinking amount.

By the way, the inventors investigated the relationship between the current flowing through the opening/closing motor and the support motor and the gripping amount of the grab bucket when the opening/closing motor and the support motor rotate at a constant speed, avoiding acceleration and deceleration of the opening/closing motor and the support motor. However, the results shown in FIGS. 2 to 4 were obtained.

FIG. 2 shows the relationship between the current value of the opening/closing motor and the amount of grip, and FIG. 3 shows the relationship between the current value of the support motor and the amount of grip.

Moreover, FIG. 4 shows the relationship between the current value and the gripping amount when the current flowing through the opening/closing motor and the current flowing through the support motor are added.

As can be understood from these figures, the current value flowing through each motor and the gripping amount are approximately proportional, and the current value of the opening/closing motor, the current value of the support motor, or the current value of the opening/closing motor and the support motor is By detecting any one of the added current values, the gripping amount can be determined from the relationship between the current value and the gripping amount.

Note that, as is clear from FIG. 4, it is preferable to detect the amount of packets grabbed using the total value of the currents of the opening/closing motor and the support motor.

The amount of grip at any given grip is compared with a predetermined target set value, and if the amount of grip exceeds the target set value, the slack length of the support rope is determined at the next time of grip. If the gripping amount is less than the target set value, the slack length of the support rope can be increased to increase the sinking amount at the next gripping, and the gripping amount will be near the target set value. The amount can be controlled.

Note that there is a nearly proportional relationship between the motor current value and the gripping amount, so convert the target set value into a current value in advance and directly compare the motor current value and the target set value. You can do it like this.

In addition, by setting the target value to be the maximum lifting load of the crane and the rated grasping amount of loose materials determined by the type of grab bucket used, unreasonable force will not always be applied to the crane during cargo handling operations. Cargo handling can be carried out with maximum efficiency.

Next, an embodiment of the second invention will be described in detail.

This embodiment is shown in FIG. As shown in the figure, resistors R1 and R2 are connected to the opening/closing motor 14 and the support motor 20, and each resistor R1JR2 is connected to a current detector 24.

The current detector 24 detects the current value of the opening/closing motor 14, the current value of the support motor 20, or the current value of the opening/closing motor 14 and the support motor 20.

Therefore, it is not necessary to connect to the opening/closing motor 14 and the support motor 20 as shown in the figure, and it may be connected only to the opening/closing motor 14 or the support motor 20.

The current detector 24 is a gripping amount calculator 2 that calculates the gripping amount of the grab bucket from the current value detected by the current detector 24.
6.

The gripping amount calculator 26 calculates the gripping amount of the grab bucket by, for example, multiplying the detected current value by a proportionality constant.

The gripping amount calculated by the gripping amount calculator 26 is input to a comparator 28, and is compared with a preset value set by a gripping position setting device 30 provided on the operation desk.

The comparator 28 calculates the difference between the calculated gripping amount and the set value, and a signal corresponding to this difference is input to the sinking amount calculator 32.

The amount of sinking calculator 32 calculates the amount of sinking based on the signal input from the comparator 28, and manually inputs the amount to the support motor control device 34 connected to the support motor 20.

The support motor control device 34 adjusts the amount of slack in the support rope by rotating the support motor 20 forward or reverse at the next time of gripping, based on the calculation result input from the sinkage amount calculation device 32.

As a result, if the gripping amount is larger than the set value at any gripping time, the sinking amount is controlled to be smaller in the next gripping, and if the gripping amount is smaller than the set value, the sinking amount is reduced in the next gripping. controlled to increase
The amount of grip on the grab bucket 1 is controlled to be close to a set value, for example, the rated load.

As explained above, according to the present invention, the amount of grasping of the grab bucket is controlled by the amount of slack in the support rope when the grab bucket is closed, and the amount of slack in the support rope when grabbing the grab bucket is set to a predetermined target. Since the value is determined based on the value and the current value of the motor during hoisting, the amount of grab buckets grabbed is controlled near the target set value, equipment is protected, and operation can be performed at maximum cargo handling efficiency. Even if the packet is allowed to free fall until it lands, there is no problem with subsequent control, and during such control, no wasted time occurs when the packet falls.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional grab bucket, FIGS. 2 to 4 are diagrams showing the relationship between the motor current value and the grab amount of the grab bucket, and FIG. 5 is a diagram of a conventional grab bucket according to the second invention. FIG. 2 is a block diagram showing one embodiment. 2... Grab bucket, 6... Opening/closing rope, 14... Opening/closing motor, 10...
Support rope, 20...Support motor, 24...
...Current detector, 26...Gripping amount calculator, 2
8...Comparator, 32...Sink amount calculator, 34...Support motor control circuit.

Claims (1)

[Scope of Claims] 1. In controlling the gripping amount of a grab bucket that reciprocates while being supported by a support rope wound by a support motor and is opened and closed by winding or unwinding the opening/closing rope by the opening/closing motor. After grasping the amount, detect at least one of the current value of the opening/closing motor and the current value of the support motor, and detect the detected current value or the grasped amount of the packet obtained from the detected current value. Compare with a predetermined target setting value, and based on the comparison result,
A grab characterized in that when the amount of grasping is small, the slack length of the support rope at the time of the next grasping is lengthened, and when the amount of grasping is large, the slack length is determined to be short to adjust the amount of sinking of the grab bucket. A method for controlling the amount of a bucket to grasp. 2. Detecting the current value of at least one of the opening/closing motor that opens and closes the grab bucket by winding or unwinding the opening/closing rope and the support motor that can reciprocate the grab bucket by winding or unwinding the support rope. a current detector; a gripping amount calculator that calculates the gripping amount of the grab bucket from the current value detected by the current detector;
A comparator that compares the gripping amount calculated by the gripping amount calculator with a preset setting value, and based on the signal from the comparator, when the gripping amount is small, the support rope for the next gripping When the slack length of the grab bucket becomes long and the gripping amount is large, a sinking amount calculating unit calculates the sinking amount of the grab bucket so that the slack length becomes short, and the support A grasp amount control device for a grab bucket, including a support motor control device for controlling a motor.