JPH07125981A - Automatic operating method for inverter-controlled scrap crane with lifting electromagnet - Google Patents

Abstract

PURPOSE:T o prevent the occurrence of the irregular winding of a hoisting rope and an inverter trip. CONSTITUTION:This automatic scrap crane with a lifting electromagnet 7 controls hoisting, traversing, and traveling motors with an inverter. It is provided with load gauges 23 and a deflection angle detecting device 24 detecting the crossing angle between the vertical direction of a crab and a hoisting rope. The landing of the lifting electromagnet 7 is detected and the displacement in the horizontal direction of the crane is corrected based on the output signals of them, then the crane is controlled for the hoisting, traversing, and traveling actions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic operation method of an inverter-controlled crane with a lifting electromagnet for loading and unloading scraps, and is particularly suitable for preventing irregular winding of a hoisting rope and inverter trip due to displacement of the hoisting electromagnet. Automatic operation method of an inverter-controlled clap crane with a simple lifting electromagnet.

[0002]

2. Description of the Related Art A state in which a conventional overhead crane with a lifting electromagnet is used for manual cargo handling will be described with reference to the drawings. FIG. 6 is an explanatory view of cargo handling of the crane. In the figure, 1 is a club, 2 is a rail on a girder, 3 is a scrap pile, 4 is a hoisting drum, 5 is a hoisting rope, 6 is a hook block, 7 is a hoisting electromagnet, 8 is an equalizer sheave, 9 Is a cable reel for supplying power to the lifting electromagnet 7. Further, it has an inverter for controlling the hoisting, traversing, and traveling motors not shown. The scrap piles 3 are piled up in a scrap yard in a pile shape and each has an inclined surface.

When the scrap is transported from the scrap pile 3 to the hopper (not shown), the driver visually checks the position of the scrap and the height of the pile from the driver's cab (not shown) provided on the crane, and the lifting electromagnet 7 is set. The club 1 is manually traversed and run so as to come to the optimum position A.

Then, the hoisting electromagnet 7 is unwound at a full speed until it does not collide with the floor, the hoisting electromagnet 7 is made to collide with the scrap pile 3 to press the scrap, and the hoisting electromagnet 7 is hung in a state in which the adsorption efficiency of the hoisting electromagnet 7 is improved. The upper electromagnet 7 is excited to adsorb scrap, and the hoisting rope 5 is hoisted and hoisted. In this case, due to the inclination of the scrap pile 3, the lifting electromagnet 7 is moved to the point Q.
Assuming that the hoisting rope 5 has slid down, the hoisting rope 5 is hung diagonally from the point A to the point Q as shown by the dotted line.

Therefore, in order to prevent the inverter from tripping due to overloading due to irregular winding of the hoisting rope 5 and diagonal hoisting, the driver moves the club 1 to a point B just above the hoisting electromagnet 7 and then winds the hoisting rope 5. It is driving to cut the ground.

[0006]

However, in order to automatically operate the conventional inverter-controlled crane with a lifting electromagnet for manual operation of a driver for scrap cargo handling, there are the following problems. That is, when the hoisting operation is performed while the position of the hoisting electromagnet 7 is deviated as described above, the hoisting rope 5 has W / cos θ (where W is the weight of the hoisting device itself and scrap attached to the hoisting device 7). The total of the weight, θ, is applied with a tension of an angle at which the line connecting the hook block 6 and the points A and B intersects with each other, and is also pulled in the B direction so that it is laterally (running) in the B direction while being rolled up. .

Therefore, a force in the reverse rotation direction is applied to the motor through a speed reducer (not shown), a starting current of a value larger than a set value flows in the inverter depending on the size of the angle θ, and the protection circuit operates.
The inverter trips. Even if the trip does not occur, problems such as load swing and irregular winding of the hoisting rope occur. Since such a problem cannot be solved, an inverter-controlled automatic crane with a lifting electromagnet for scrap only has not yet been put to practical use.

The present invention has been devised in view of the above circumstances, and it is an object of the present invention to provide an automatic operation method of an inverter-controlled scrap crane with a lifting electromagnet, which prevents irregular winding of a hoisting rope and inverter trip. Has an aim.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a scrap crane with a hoisting electromagnet for controlling hoisting, traversing and traveling motors with an inverter, a load meter for detecting a hoisting load, a vertical direction of a club, and a hoisting rope. It has a deflection angle detection device that detects the intersecting angle of, and after performing the landing detection of the lifting electromagnet and the correction of the horizontal displacement of the crane based on these output signals, It is characterized by being able to traverse and run.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for automatically operating an inverter-controlled scrap crane with a lifting electromagnet according to the present invention (hereinafter referred to as the method of the present invention) will be described below with reference to the drawings. 1 is an explanatory view of a main part of a crane to which the method of the present invention is applied, FIG. 2 is a control block diagram of the crane, FIG. 3 is a flow chart illustrating the operation of the method of the present invention, FIG. 4 is a flow chart following FIG. 3, and FIG. It is an illustration figure explaining 1 cycle of scrap cargo handling. The same parts as those of the prior art will be described with the same reference numerals.

Generally, an inverter-controlled automatic crane with a lifting electromagnet includes a rope hanging length detector 21 for detecting the hanging length of the hoisting rope 5, and a position detector 22 for detecting the horizontal coordinate position of the lifting electromagnet 7. And a control unit 25 including a microcomputer.

On the other hand, the inverter-controlled scrap crane with a lifting electromagnet (hereinafter referred to as the crane of the present invention) 20 for carrying out the method of the present invention, in addition to the above, further includes a load meter 23 for detecting a hanging load, and a club. The deflection angle detection device 24 detects the angle θ at which the vertical direction of 1 and the hoisting rope 5 intersect.

The rope droop length detector 21 is, for example, an encoder, which is connected to the rotary shaft of the hoisting drum 4.
The length of the hoisting rope 5 fed from the hoisting drum 4, that is, the height of the hoisting electromagnet 7 is measured.

The rope droop length detector 21 may be a distance measuring device using a laser or an ultrasonic distance meter other than the above. The distance measuring device is composed of a laser or ultrasonic wave measuring device (not shown) installed at a proper position of the club 1 and a target (not shown) provided at a suitable position of the lifting electromagnet 7, and the laser light or the ultrasonic wave hits the target. It is configured to receive the returning light or sound waves and measure the distance.

The position detector 22 detects coordinate positions (addresses) which are set by subdividing the X-axis (transverse direction) and the Y-axis (traveling direction) of the scrap yard at predetermined distance intervals in advance. 11 and traveling motor 12
(See FIG. 2), each of which is provided with encoders 22a and 22b that are arranged in series.

In addition to the above, the position detector 22 is a large number of limit switches provided at the coordinate positions of a traverse rail and a traveling rail not shown in the drawing, and the limit switches are operated by a striker (not shown) attached to the crane. You may

The load cell 23 is a strain resistance type load cell of a metal resistance type or a semiconductor type, which is arranged at a proper position of the club 1. In addition to this, it may be an electric load cell 23 'attached to an electric circuit of the hoisting motor 11 and converting the power consumption of the hoisting motor 11 into a load and outputting the load (in FIG.
3 and FIG. 2 shows the electric load cell 23 ').

The load meter 23 has a load W1 when the lifting electromagnet weight WM is not applied to the hook block 6, that is, an unloaded load including the hook block 6 and the hoisting rope 5,
The load W2 when the weight WM of the hoisting electromagnet is applied, that is, (W1 + WM), and the load W when the scrap is adsorbed.
3, that is, (load W2 + adsorption scrap weight WS) is detected and output.

The deflection angle detecting device 24 is disclosed in, for example, Japanese Patent Laid-Open No. 63-63.
-225118, which is similar to the crane swinging tool deflection angle detecting device.

That is, a sensor (not shown) having a sheave side (not shown) provided above the central portion of the hoisting electromagnet 7 and means mounted vertically to the club 1 and rotatable in two directions, traverse and running. A base, an inclinometer arranged on the upper surface of the sensor base to detect the traverse of the crane 20 and the inclination angle in the traveling direction, and an accelerometer (not shown) attached to the club 1 for detecting the traverse of the crane 20 and the acceleration in the traveling direction. And a detection rope, one end of which is connected to the lower end of the sensor base and the other end of which is connected to the detection rope take-up reel via a sheave-side sheave and a guide sheave disposed below the club 1.

The outline of the operation of the deflection angle detecting device 24 will be described below. When the crane travels sideways, the sheave on the lifting equipment side also shakes, which causes the detection rope and the sensor base to tilt at the same angle. This angle is detected by the inclinometer, and the control unit 25
It will be entered in (below). The acceleration applied to the club 1 by the swing of the sheave on the lifting tool side is detected by an accelerometer and input to the control unit. The control unit 25 is configured to calculate the traverse angle of the sheave on the lifting device side and the deflection angle in the traveling direction based on the input.

The control unit 25 includes a microcomputer, the detection signals of the above-mentioned detectors and meters 21, 22, 23, 24 are input, calculation, comparison and judgment are performed based on the detection signals, and the result is obtained. Based on this, the hoisting motor 10, the traverse motor 11, and the traveling motor 12 are controlled via the inverter 13, and the excitation of the hoisting electromagnet 7 is controlled via the hoisting electromagnet control panel 14.

Further, the control unit 25 is connected to a management CPU 26, which is a host computer, so that data such as the destination and load of the crane 20 can be transmitted and received.

Next, the operation of the method of the present invention will be described with reference to FIGS. In the description of the flowchart, S1 and S
2 ... indicates a step number. (1) In the instruction waiting state, a cargo handling command such as a cargo handling address of the scrap yard, a scrap loading hopper address, a scrap lifting weight, etc. is input to the control unit 25 from the management computer 26 to start, and lateral traveling is turned on (S1). The detectors 22a and 22b detect the command address (S2), and Y
If ES is reached, the vehicle is turned off laterally (S3). If NO, S
Return to 1. (2) Then, the lowering is turned on (S4). At this time, full speed or fine speed is selected based on a preset program depending on the type of scrap.

(3) The load W is detected by the load meter 23. If W <W2, that is, the load W is smaller than (unloaded load W1 + suspending electromagnet weight WM), it is detected that the suspending electromagnet 7 has landed on the scrap (S5). If NO, the process returns to S4. (4) The hoisting rope is tensioned by turning off the hoisting and switching the electric circuit so that the hoisting weak torque that allows hoisting with no load W1 is obtained (S6).

(5) At the same time, an excitation command is issued to the suspension electromagnet control panel 14 to turn on the excitation of the suspension electromagnet 7 (S7) to adsorb the scrap. (6) Next, the deflection angle θ of the lifting electromagnet 7 is detected based on the detection input of the deflection angle detection device 24 (S8). (7) When the hoisting rope 5 exceeds the permissible value of the deflection angle θ intersecting the club vertical line, the crane 20 is traversed so as to be within the permissible value and traveling position correction is performed (S9).

(8) It is confirmed whether the exciting current I of the suspension electromagnet 7 is a predetermined value I ₀ or more (S10). This is because the lifting electromagnet 7 is pulled out from the scrap pile in the overshoot or overexcite state. (9) If the exciting current I is greater than or equal to the predetermined value I _{0 in} S10 and the positional deviation amount is within the predetermined value in S8, the winding weak torque is turned off and the winding is turned on (S11). .

(10) Detecting the ground cutting of the lifting electromagnet 7 and W>
If W2, that is, the load W is larger than (the unloaded weight W1 + the lifting electromagnet's own weight WM) (S12), the winding is stopped when the winding reaches the predetermined winding height H1 (S13). If the predetermined winding height H1 has not been reached, the process returns to S11.

(11) The suspended scrap is traversed to the hopper (S15), and when it arrives at the loading address (S1).
6) Then, the sideways and traveling are turned off (S17), the lowering is turned on (S18), and when the predetermined release height H2 is reached (S19),
The scrap is released and the lower part is turned off (S20).

(12) Then, the winding is turned on (S21), and when the predetermined height H1 is reached (S22), the winding is turned off (S2).
3) One cycle is completed. The one cycle end signal is transmitted to the management computer 26 and waits for the next start instruction. (13) If the exciting current I is greater than or equal to the predetermined value I ₀ in S10 described in (8) above, hoisting ground cutting is performed, and if ground cutting is detected (S12), the rated exciting current I ₀ is switched to. (S2
4) If the release height is H2 in S19, the excitation is turned off (S25) and the reverse excitation is performed (S26). (14) After the time elapses for a predetermined time (S27), the winding is turned on (S21), the reverse excitation is turned off (S28), and one cycle is completed. Reverse excitation is turned off and the process returns to the next cycle instruction wait.

(15) In S13, the load W = W3-W2,
That is, the scrap weight WS is calculated (S29), input to the management computer 26 and recorded (S30).

FIG. 5 shows the hoisting speed and hoisting electromagnet 7 of the crane 20 according to the method of the present invention described in the above flow chart.
FIG. 4 is an exemplary diagram showing changes in the exciting current of the above with time.

In the illustrated example, the operation is as follows. That is, the crane 20 reduces the hoisting speed from before the landing point R and lands at the point R at time T1. When the hoisting is turned off and the landing is detected, the rope is tensioned by the hoisting weak torque until time T2.

Hoisting electromagnet 7 from time T1 to time T3
Is gradually increased from the rated current and maintained as it is from time T3 to time T4, and is decreased to the rated current from time T4.
The hoisting motor 10 is turned on from time T3, and after ground cutting at a low speed, the hoisting motor 10 is speeded up and turned off until time T5 at which a predetermined hoisting height is reached at time T4. Then, run sideways, release the excitation at a predetermined position to the release height, and release the excitation at time T6,
Reverse excitation is performed at time T7 to completely remove the attachment of scrap.

As described above, by carrying out the operating method of the present invention, during one cycle of scrap cargo handling, the operation interruption due to the irregular winding of the warp and the inverter trip is eliminated, and the smooth and efficient scrap cargo handling can be automated.

[0036]

As described above, the method of the present invention is applied to the winding,
In a scrap crane with a hoisting electromagnet that controls traverse and travel motors with an inverter, it has a load meter that detects the hoisting load and a swing angle detection device that detects the angle between the vertical direction of the club and the hoisting rope. Based on these output signals, after detecting the landing of the hoisting electromagnet and correcting the horizontal displacement of the crane, the ground hoisting and traverse,
It is characterized by running.

Therefore, automation can be performed in place of conventional cargo handling of scrap in a scrap yard in a bad environment, and since there is no irregular winding of rope or operation interruption due to inverter trip, it contributes to improvement of productivity. It will be extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of a crane to which the method of the present invention is applied.

FIG. 2 is a control block diagram of the crane.

FIG. 3 is a flowchart explaining the operation of the method of the present invention.

FIG. 4 is a flowchart following FIG.

FIG. 5 is an exemplary diagram illustrating one cycle of scrap cargo handling.

FIG. 6 is a view showing a conventional technique and is an explanatory view of cargo handling of a crane.

[Explanation of symbols]

 7 Hoisting electromagnet 10 Hoisting motor 11 Traverse motor 12 Traveling motor 13 Inverter 14 Hoisting electromagnet control panel 22 Position detector 23 Load meter 24 Swing angle detection device 25 Control unit 26 Management CPU

Claims (1)

[Claims] 1. A scrap crane with a hoisting electromagnet, which controls hoisting, traversing and traveling motors with an inverter,
It has a load meter that detects the hanging load and a swing angle detection device that detects the angle at which the vertical direction of the club intersects with the hoisting rope, and based on these output signals, detection of the landing of the hoisting electromagnet and After correcting the horizontal displacement of the crane,
An automatic operation method for an inverter-controlled scrap crane equipped with a lifting electromagnet, characterized in that it is capable of hoisting, traversing, and traveling.