JPS6010997B2 - How to prevent a bucket crane from falling over - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing a bucket crane from overturning.

During cargo handling operations in which solid waste loaded in storage bits or objects such as accumulated earth and sand, sand, and rocks are transported to a designated location using a bucket crane, the bucket is lowered to the required position and almost the entire weight of the bucket is removed. The system automatically detects that the bucket is supported by an object, stops lowering, and then closes the bucket to grab the object. However, if the surface of the object is sloped, the bucket may After the bucket comes into contact with an object, the bucket may rotate and fall until almost all of the bucket is supported by the object.

For this reason, a bucket crane has been proposed that uses a detection device that includes three or four detection ropes attached to the top of the bucket to detect the inclination of the bucket and prevent it from falling over (see Utility Model Application No. 19976/1983). However, in such a subordinate bucket crane, it is necessary to add a new bucket size detection device to the bucket. This invention was made in view of the above circumstances, and its purpose is to prevent the bucket from overturning by using information obtained from the support rope suspending the bucket, and to install a tilt detection device on the bucket. An object of the present invention is to provide a method for preventing a bucket from overturning that does not require any new addition.

The bucket overturn prevention method according to the present invention lowers the bucket to a required zero position using a bucket crane in order to pick up the accumulated objects and transport them to the required location, so that almost the entire weight of the bucket is supported by the objects. During automatic operation, which automatically detects the problem and stops lowering, and then closes the bucket and grabs the object, part of the bucket comes into contact with the object due to the load of the bucket on the support rope suspending the bucket. The system automatically detects when the lowered bucket has touched the object and when almost the entire weight of the bucket is supported by an object. The length of the support rope drawn out by the operator is monitored, and if the length of the drawn out rope reaches or exceeds a predetermined allowable line length by the time the bucket grasping operation is completed, automatically stops lowering.

Detection that a portion of the bucket has touched an object and that substantially the entire weight of the bucket has been supported by the object can be done by directly monitoring the bucket's hanging load on the support rope, or by directly monitoring the load of the bucket on the support rope. When lowering the bucket by dynamically braking the electric motor, the suspended load can also be indirectly monitored by the lowering speed of the bucket. The hanging load of the bucket on the support rope is approximately the weight of the bucket during constant-velocity lowering, and begins to decrease when a part of the bucket, such as a pawl, touches an object, and gradually decreases as the pawl or other part of the bucket bites into the object. decreases to almost zero when almost the entire weight of the bucket is supported by an object. Therefore, by monitoring the hanging load of the bucket, it is possible to detect that a portion of the bucket has contacted an object and that substantially the entire weight of the bucket has been supported by the object. When the support motor is dynamically braked, the lowering speed of the bucket is determined by the load, that is, the hanging load of the bucket, so the hanging load can be monitored based on the lowering speed. The lowering speed can be obtained from the rotation speed of the support motor. The length of the supporting rope to be pulled out is obtained from the amount of rotation of the supporting conch shell. At this time, the support winding and its rotation amount are constantly monitored.
The amount of lowering of the bucket converted from the amount of rotation when a part of the bucket contacts an object is memorized, and then the amount of lowering of the bucket converted from the amount of rotation that changes from moment to moment and the amount of lowering of the bucket that is stored are stored. The difference between the lowering amount and the length of the rope can be taken as the length of the rope, or the amount of rotation of the support winding drum after a part of the bucket comes into contact with the object can be taken directly and converted to the length of the rope. You can also do that. The allowable line extension is the maximum length of the support rope that can be drawn out after a part of the bucket contacts an object, and is the maximum length of the support rope that can be drawn out after the bucket touches the mirror slope of the object and then rotates and is just before falling. It is desirable that the length of the supporting lobe be equal to or somewhat smaller than this.

Next, an example of implementing the present invention using a computer will be described with reference to the drawings.

In FIG. 1, 21 is a support motor that hoists and lowers the bucket, 22 is an opening/closing motor that opens and closes the bucket, 23 is a lowering amount detector for the support rope suspending the bucket, and 24 is the support rope Hanging load detector, 25
26 is a crane control device that controls the support motor 21, opening/closing motor 22, etc., and 27 is a lowering amount detector 2.
3. An input/output device 28 is connected to the input/output device 27, and inputs signals from the hanging load detector 24 and limit switch 25 for bucket fully closed detection, and outputs control commands to the crane control device 26. This is a computer that controls automatic driving.

A control program shown in FIG. 2 is stored in the computer 28. The computer 28 controls the lowering of the bucket, the gripping operation, and the stop of lowering the bucket in accordance with the following procedure. Step (1' Issue a lowering start command.

In order to lower the bucket, a lowering start command is issued to the control device 26 through the input/output device 27.

Based on this, the control device 26 outputs a lowering start signal to operate the support motor 21, and lowering is performed. Step ■ Determine whether any part of the bucket has touched an object.

The suspension load signal B of the support rope is sent from the detector 24 through the input/output device 27 to the computer 28 every moment, and the computer 28 converts this signal into a suspension load G, and this value is greater than the suspension load setting value GI. Determine whether or not.

The set value GI is preset to a value slightly smaller than the bucket's own weight, and if a part of the bucket comes into contact with an object, the hanging guard weight G will decrease and become below the set value GI, but if not. The hanging load G is approximately the weight of the bucket and is larger than the set value GI. Hanging load G is set value G
If it is less than I, proceed to the next step [3}'; if not, proceed to step '2 to check the hanging load G again.
Repeat step 1. Step [31] Store the amount of lowering of the support rope.

The support rope lowering amount signal A is sent from the detector 23 through the input/output device 27 to the computer 28 from time to time, and the computer 28 converts this signal into the lowering amount L, and uses this value as the lowering amount memory value. Store as LM.

Thereby, the amount of lowering when a part of the bucket comes into contact with an object is stored. Step '4) Determine whether or not the length L-LM of the supporting rope is greater than or equal to the allowable line drawing amount LL.

From the lowering amount L read every moment, the lowering amount memory value LM
Calculate the payout rope length L-LM by subtracting J. When the bucket is on the verge of falling, the line rope length L-LM
is equal to or greater than the allowable line width LL, so in this case the process proceeds to step (11) to stop the lowering, otherwise the process proceeds to the next step (5} one step).
J step (5) Determine whether almost the entire weight of the bucket is supported by the object.

The suspension load G that is input from time to time is compared with the suspension load set value G2.

The set value G2 is preset to a value close to zero, and if almost the entire weight of the bucket is supported by the object, the hanging load G will be less than the set value G2, so in this case, proceed to the next step If not, return to step ① to check the line out rope length again. Step ■Issue a lowering stop command.

When a lowering stop command is issued to the control device 26 through the input/output device 27, the control device 26 outputs a lowering stop signal based on this, and stops the support motor 21.

Step [7] Issue a command to start sinking and grabbing.

When a command to start sinking and grabbing is issued to the control device 26 through the input/output device 27, the control device 26 outputs a lowering signal and a bucket closing signal based on this command, and so-called sinking and grabbing is performed in which the bucket closes while descending.

Step '8': It is determined whether the exposed rope length L-LM is greater than or equal to the allowable customer payout amount LL.

There is a risk that the supporting rope will be fed out even during sinking and the feeding rope length L - LM will exceed the allowable line drawing amount LL, causing the bucket to overturn, so a check similar to step [41] is performed.

If the length L-LM of the pulling rope is equal to or greater than the allowable line drawing amount LL, the process proceeds to step (11); otherwise, the process proceeds to the next step. Determine whether the step side bucket is fully closed.

When the bucket is completely closed, a fully closed bucket signal C is sent from the limit switch 25 to the computer through the input/output device 27.

If the fully closed signal C is output, proceed to the next step (10), and if it is not output, check the length of the rope again L - L.
Return to step ■ to check M. step o
o Issue a sinking and grabbing stop command.

When a sinking and grabbing stop command is issued to the control device 26 through the input/output device 27, the control device 26 outputs a lowering stop signal and a bucket opening/closing stop signal based on this command.

This completes the bucket grasping operation. Step (1
1) Issue a lowering stop command.

Similar to step [6}, a lowering stop command is issued to stop the support motor.

This causes the bucket to stop just before tipping over. Step (12) Issue a warning signal that the bucket is about to overturn.

Based on this signal, it is possible to flash a warning lamp, sound a warning buzzer, or take other necessary measures.

As explained in detail above, according to the present invention, after automatically detecting that a part of the lowered bucket has come into contact with an object, the length of the support rope that is paid out during lowering is determined. By monitoring it, it is possible to judge whether the bucket is on the verge of overturning, and if the above-mentioned rope length reaches or exceeds the allowable rope length, the system automatically lowers the rope. By stopping the bucket, it is possible to prevent the bucket from falling over.

In addition, it detects that part of the bucket has come into contact with an object due to the load applied to the support rope that suspends the bucket, and that almost the entire weight of the bucket is supported by the object, and the line of the support rope is determined. By monitoring the length of the rope, it is determined whether the bucket is on the verge of tipping over, so information obtained from the support rope can be used to prevent the bucket from tipping over. There is no need to add it to

[Brief explanation of the drawing]

The drawing shows an example of implementing this invention using a computer,
FIG. 1 is a block diagram, and FIG. 2 is a flowchart showing a control procedure by a computer. L-LM... Length of the rope to be delivered, LL... Amount of payout allowed by the customer. Figure 1 Section 2 Mouse

Claims (1)

[Claims] 1. A bucket crane lowers the bucket to the required position in order to pick up the piled objects and transport them to the required location, and automatically detects that almost the entire weight of the bucket is supported by the object. During the automatic operation in which the bucket is stopped and the object is grasped by closing the bucket, a part of the bucket comes into contact with the object due to the hanging load of the bucket, which is applied to the support rope suspending the bucket, and almost all of the bucket After automatically detecting that the entire weight is supported by an object and automatically detecting that a part of the lowered bucket has touched the object, the supporting rope is unwound. The system monitors the length of the payout rope, and if the length of the payout rope reaches or exceeds a predetermined allowable payout amount by the time the bucket grabs the bucket, the system automatically lowers the rope. How to stop a bucket crane from tipping over.