JPH03128890A - Control method for steel plate lifting number selection - Google Patents

Abstract

PURPOSE:To certainly lift a designated number of steel plates by determining the exciting current of a lifting magnet in consideration of the plate width and position of a narrow steel plate of a plurality of piled steel plates including a steel plate narrower than the adsorbing surface width of the lifting magnet. CONSTITUTION:A correction exciting current is predetermined by a calculating circuit 5 with the plate width and position of a narrow steel plate of a plurality of piled steel plates including a steel plate narrower than the adsorbing surface width of a lifting magnet 11 as a parameter. The exciting current when only a steel plate wider than the adsorbing surface width of the lifting magnet 11 is lifted is taken as a standard exciting current. The standard exciting current is corrected by the correcting exciting current, whereby a designated number of steel plates can be precisely lifted, even if a plurality of piled steel plate include steel plates narrower than the adsorbing surface width of the lifting magnet 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling the number of suspended steel plates, and particularly to a method for controlling the number of suspended steel plates when lifting a specified number of steel plates by an overhead crane equipped with a lifting magnet.

[Prior Art] Overhead cranes equipped with lifting magnets are widely used to transport steel plates. Lifting magnet refers to a lifting device for a crane that is equipped with one or more electromagnets. In an overhead crane for transporting steel plates, one or more lifting magnets are suspended via chains from a lifting beam that is hoisted up by a trolley.

When transporting steel plates, it may be necessary to lift a specified number of steel plates from a stack of steel plates. In such a case,
The excitation current of the lifting magnet is adjusted so that the magnetic attraction force acting between the bottom surface of the lifted material and the top surface of the non-lifted material is smaller than the weight of the non-lifted material, so that the lifted material and the non-lifted material are separated. Separated. For example, in order to separate only the lifted material from the non-lifted material, first the lifting magnet to be used is selected according to the length of the lifted material. Next, the lifting magnet pitch is calculated from the size of the lifting material, etc., and the lifting weight to be applied to each lifting magnet is determined. Then, in consideration of the shared weight and the deflection of the steel plate during lifting, the excitation current of each selected lifting magnet is set according to the total thickness of the lifting material and the steel type.

Another method for selecting the number of suspended steel plates is disclosed in Japanese Patent Application Laid-Open No. 501547.
There is a method disclosed in No. 67. In this method, the magnetic poles in the lifting magnet are arranged alternately as N poles and S poles, or in a staggered manner.
This makes it possible to select the S pole from a wide range. Another method is the method disclosed in Japanese Utility Model Application No. 51105279. In this method, a suction attachment with a concave portion formed on the steel plate suction surface of each magnetic pole in a lifting magnet is attached, thereby making it possible to widely control the penetration density and depth of magnetic flux into the steel plate.

[Problems to be Solved by the Invention] As described above, the excitation current of the lifting magnet is set in advance so that the lifting magnet attracts only the suspended material and detaches the non-lifted material. At this time, the size of the hanging material, the number of hanging materials, etc. are taken into consideration.

However, when suspending multiple steel plates, including steel plates narrower than the width of the lifting magnet's suction surface, the attraction force generated on the suction surface depends on the width of the narrow steel plates and their stacking position, or the characteristics of the wide steel plates. to differ greatly. Figure 4 shows the first
The standard pattern shown in the figure (when lifting a steel plate wider than the suction surface width of the lifting magnet) and a
Examples are shown in which the excitation current-attractive force characteristics were actually measured for patterns to patterns d. As is clear from FIG. 4, the characteristics of pattern a and pattern b are significantly different from those of the standard pattern. In addition, the flow of magnetic flux in a lifted steel plate changes in a complicated manner depending on the width of the narrow steel plates and the stacking position thereof, and it is difficult to accurately estimate the excitation current that can be used for hanging. For these reasons, when hoisting a plurality of steel plates including narrow steel plates, even with the prior art described above, it was not possible to reliably separate the specified number of steel plates. For this reason, the crane operator adjusts the excitation current of the lifting magnet while observing the condition of the steel plates to be lifted, and uses trial and error to lift the specified number of steel plates. As a result, the working time for sorting the steel plates was increased, the working efficiency of the crane was reduced, and it was not possible to automate the sorting of the number of steel plates to be hung.

Therefore, it is an object of the present invention to provide a method for controlling the number of suspended steel plates that can reliably lift a specified number of steel plates even when lifting a plurality of steel plates, including steel plates whose width is narrower than the width of the suction surface of a lifting magnet. That is.

[Means for solving the problem] The method for controlling the number of suspended steel plates of the present invention sets the excitation current of the lifting magnet in advance according to the number of suspended steel plates,
In the method of lifting a specified number of steel plates from a stack of steel plates by adsorbing them with a rich four-ring magnet, the narrow steel plates in a stack of multiple steel plates including steel plates whose width is narrower than the suction surface width of the lifting magnet are used. The corrected excitation current is determined in advance using the plate width and its position as parameters.

Then, the excitation current used when lifting only a steel plate wider than the width of the attraction surface of the lifting magnet is set as a reference excitation current, and the reference excitation current is corrected by the correction excitation current.

The reference excitation current is obtained by experimentally determining the excitation current-adsorption force characteristic using an actual machine or a simple experimental device. This result is stored, for example, in the -1 place computer as an arithmetic table. Then, during the steel plate lifting operation, the excitation current of the lifting magnet is determined based on the above calculation table according to the lifting conditions. Although it varies depending on the lifting conditions, the corrected excitation current is 11 to 2.
It becomes about 0 times. Note that the width narrower than the suction surface width of the lifting magnet is 1 to 50% smaller than the suction area of the lifting magnet, although it varies depending on the lifting conditions.
It means something narrow. Also, the maximum number of hanging sheets is, for example, 6.
It is one piece.

In the above method for controlling the number of suspended steel plates, when a plurality of steel plates including steel plates whose width is narrower than the width of the suction surface of the lifting magnet are stacked, the steel plate whose width is narrower than the width of the suction surface of the lifting magnet is placed on top. The correction excitation current is divided into four patterns: a pattern located at the top, a pattern located at the bottom, a pattern located in the middle, and a pattern where all narrow steel plates are used. The reference excitation current may be determined for each pattern and corrected according to the pattern.

FIG. 1 shows the above four patterns. In Figure 1, pattern (a) is a pattern in which a narrow steel plate is located in the middle, pattern (b) is a pattern located at the top, pattern (c) is a pattern located at the bottom, and pattern (d ) are all narrow steel plate patterns.

[Function] The excitation current of the lifting magnet is determined by taking into consideration the width and position of the narrow steel plates in a stack of multiple steel plates, including steel plates whose width is narrower than the width of the lifting magnet's attraction surface, so the specified number of sheets is determined. It is possible to obtain an excitation current that accurately separates the suspension.

Further, by patterning a stacked state of a plurality of steel plates including a steel plate whose width is narrower than the width of the suction surface of the lifting magnet, various stacked states of the steel plates can be consolidated.

[Example] The overhead crane for transporting steel plates used in this example has five lifting magnets arranged along the lifting beam. Each lifting magnet is equipped with 3x6 electromagnets. The width of the attraction surface of the lifting magnet is 1880 mm.

Using a lifting magnet having the above specifications, the coefficients for correcting the reference excitation current for patterns a and b shown in FIG. 1 were actually measured, and the results are shown in Table 1. FIG. 2 is a diagram showing this correction coefficient.

The narrow correction electromagnetic current is calculated by multiplying the reference excitation current by the narrow correction coefficient.

Narrow product width W2 W, = 900mm W, = 1400mm W, = 1880mm W1≧1880mm Wl: Top plate width 1400 W2 = 900 2.0 1.8 ] , 6 1.6 1.2 1.4 1. 2 1.4 Wt,: Bottom board width (Lnth board width) Table 1 ≧ 1880 W2 = 1880 W2 2.2 2.2 1.6 1. [i 1.0 1.0 1.0 1. O W2: Intermediate plate width The rules for correcting the reference excitation current using the diagram in FIG. 2 are as follows.

(2) For narrow width correction, in the case of pattern a and pattern b, the correction coefficient is determined from FIG.

(2) For pattern C, which has a narrow material only at the bottom (tnth sheet), the excitation current is calculated from the excitation current attraction force characteristics in the same way as when calculating the reference excitation current, without performing correction using the correction coefficient.

■ When there are multiple narrow width members in the steel plate except for the two and the bottom parts, the narrowest steel plate is used as the representative width of pattern a. This is because it is the narrowest steel plate or the neck.

(2) In the case of the d pattern, the correction coefficient is determined by combining (1) and (2) above. That is, if there is a steel plate with the narrowest width among the steel plates excluding the top and bottom, the correction coefficient is determined from FIG. 2 based on ■ and ■. If the narrowest steel plate is at the bottom, please refer to ■.

If the following four conditions are satisfied, all hanging patterns including narrow width are satisfied.

0 Here, an apparatus for carrying out the method of the present invention will be explained along with its operation.

FIG. 3 is a block diagram showing an example of a control device for carrying out the method for controlling the number of suspended steel plates according to the present invention.

First, in the upper control computer 1, the lifting magnet 1 is
The number of used lifting magnets (only one is shown in FIG. 3) and the beam pitch (the distance between adjacent lifting magnets) are determined, and the results are used as a lifting magnet selection signal S5. It is outputted to the lifting magnet lifting part discriminating circuit 3 and the excitation current calculation circuit 2 as a result. In addition, the upper control computer 1 also calculates the size of steel plates, the number of suspended plates,
A reference excitation current I for each lifting magnet Il based on the number of lifting magnets used, the beam pitch, and the stacking pattern of the steel plates. 0 and the correction current setting value T ea+ Ich based on the deflection of the steel plate and other factors. Note that the reference excitation current Ion here is an excitation current that has already been corrected by 1 based on the stacking pattern of the steel plates. The obtained reference excitation current I O
n is the correction current setting value I Ca+
Ich is output to correction current calculation circuits 4.5 and 6, respectively. In the excitation current calculation circuit 2, for example #1
Assuming a lifting magnet as a representative, the reference excitation current l from the host computer 1. 1 and lifting magnet selection signal S1,. from the initial setting excitation current I. (1
) is required. And the initial setting excitation current■. (2) is set in the setting current selection circuit 8. Furthermore, the host computer 1 sends the planned lifting weight W to the lifting failure determination circuit 17.
PLMID, its maximum value WPLmax and minimum value W
P.L. 1o, the board thickness to be lifted TPLMID, its maximum value TPL□8X, and its minimum value TPL□. Output.

Meanwhile, the lifting beam is lowered from the trolley of the overhead crane. When the lifting magnet 11 lands on the uppermost steel plate of the stacked steel plates, the excitation current is transmitted from the setting current selection circuit 8 to the excitation current control device 9 to the electromagnetic coil of the lifting magnet 11. 2 is supplied as MI, and suction/adsorption of the steel plate is started.

When all the lifting magnets II attract the steel plate, hoisting is started. The hoisting control device 10 receives the signal PSL from the setting current selection circuit 8 and the hoisting position sensor 2.
The hoisting motor 30 is controlled by the signal PSM from 2.

In the process of hoisting, the ground breaking sensor I2 detects the separation of the lifted material and the non-lifted material, that is, the ground breaking for each lifting magnet 11. Signal 5 from ground cutting sensor 12
Reference numeral 11 is manually inputted to the excitation current calculation circuit 2, the set current calculation timing circuit 7, and the ground cut order determination circuit 14. The ground breaking order determination circuit 14 discriminates which lifting magnet 11 has been ground broken.

The setting current calculation timing circuit 7 receives the signal from the hoisting position sensor 22 and the ground cutting signal Sl+ manually.
A current correction start timing signal SGf is output to the excitation current calculation circuit 2. When the current correction start timing signal SGf is manually inputted, the excitation current calculation circuit 2 calculates a correction current for the excitation current due to deflection and other factors. The corrected excitation current is maintained until the steel plate is completely lifted. After complete lifting, the excitation current during transport is increased to more strongly attract the steel plate and transport it to a predetermined position. These corrected excitation currents are the lifting magnet suspension selection current I. It is supplied as R1 from the excitation current calculation circuit 2 to the set current selection circuit 8, and further supplied to the electromagnetic coil of the lifting magnet 11 via the excitation current control device 9.

For each lifting magnet 11, the magnetic flux sensor 13 detects the magnetic flux passing through the steel plate from the electromagnet, and the detected magnetic flux 521 is manually inputted to the suspension failure determination circuit 17 via the magnetic flux-plate thickness conversion circuit 15. If a thin plate occurs during the suspension, or if the number of suspended plates is large, this is detected by the suspension load sensor 16 and the suspension failure determination circuit 17.

Based on this detection result, in the case of a thin plate, lifting is performed again by a signal from the beam try control circuit 19. Furthermore, when there are a large number of steel plates to be hung, the excess steel plates are cut off by a signal from the cutting control circuit 18 based on signals from the suspension failure determination circuit 17 and the thin plate detection circuit 20.

Next, an example will be explained in which a specified number of steel plates are lifted by the above-mentioned device.

Table 2 shows examples of lifting by comparing the conventional method and the method of the present invention.

The lifting conditions in Table 2 are as follows.

(1) There were five rich ink magnets for toilet use, and all five were set to the same current value in the table.

(2) Refink McNett pitch is +800111
It is 111.

(3) The bottom numerical value of the size combination indicates the size of the non-lifted steel plate located next to the lifted steel plate.

(4) The corrected excitation current is the reference excitation current x narrow width correction coefficient.

(5) The contents of the case are as follows.

Case (1) is a test case of pattern (C) (2) is a test case of pattern (a) (3) is pattern (b)
Test case (4) is the test of pattern (d). 5 As is clear from Table 2, in case (1), that is, when only the lowest steel plate among the suspended steel plates is a narrow material, the conventional excitation current / I was able to hang it up using a method based on adsorption properties (weight calculation method). However, in other cases it was impossible to lift. On the other hand, according to the method of the present invention, the specified number of steel plates could be lifted in all cases, even if the steel plates to be lifted included narrow C-width materials.

This invention is not limited to the above embodiments.

For example, in the above embodiment, in the case of the d pattern, the above
The correction coefficient was determined by combining (1) and (2). However, in the case of the d pattern, the excitation current attraction force characteristics are determined,
The excitation current may be directly calculated in this manner.

This is because if all the steel plates to be lifted are narrow, it is easy to understand the excitation current-attraction force characteristics.

[Effects of the invention] (]) Even if there are multiple stacked steel plates including steel plates whose width is narrower than the suction surface width of the lifting magnet,
The specified number of steel plates can be lifted accurately. (2) As a result, the cycle time of the crane can be improved.

(3) The area for selecting the number of hanging steel plates has been expanded.

(4) Work time for separating steel plates has been shortened, crane work efficiency has improved, and it has become possible to automate the selection of the number of steel plates to be hung.

(5) When the stacked state of steel plates is patterned, the various stacked states of the steel plates are consolidated, and the control for selecting the number of suspended steel plates can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a stacking pattern of a plurality of steel plates including narrow steel plates, Fig. 2 is a line diagram showing an example of a correction coefficient, and Fig. 3 is a control device implementing the method for controlling the number of suspended steel plates of the present invention. FIG. 4 is a block diagram showing an example of this, and FIG. 4 is a characteristic curve diagram showing an example of exciting current-attractive force characteristics. DESCRIPTION OF SYMBOLS 1... Upper level integrated control device, 2... Excitation current calculation circuit, 3... Lifting magnet lifting part determination circuit,
4... Deflection correction current calculation circuit, 5... Lifty
8 Nkumacnet part-specific correction current calculation circuit, 6... Lifting magnet feature layer-specific correction current calculation M path, 7.
... Set current calculation timing detection circuit, 8... Set current selection circuit, 9... Excitation current selection circuit, 1o... Hoisting control device, 11... Lifting magnet].
12... Ground cutting sensor, 13... Magnetic flux sensor, 14
...Lifting magnet feature order determination circuit, 15
...Magnetic flux plate thickness conversion circuit, 16... Lifting load sensor, 17... Full suspension judgment circuit, 18... Separation control circuit, 19... Retry control circuit, 20... Thin plate detection circuit .

Claims (1)

[Claims] 1. In a method in which the excitation current of the lifting magnet is set in advance according to the number of sheets to be lifted, and a specified number of steel sheets from a stack of steel sheets are attracted and lifted by the lifting magnet, A corrected excitation current is determined in advance using the width and position of the narrow steel plate in a stack of multiple steel plates including narrow steel plates as parameters, and excitation is performed when lifting only the steel plate that is wider than the width of the lifting magnet's attraction surface. A steel plate hanging number selection control method, characterized in that the current is a reference excitation current, and the reference excitation current is corrected by the correction excitation current. 2. A stacked state in which multiple steel plates, including steel plates narrower than the width of the lifting magnet's suction surface, is placed in a pattern where the steel plate narrower than the width of the lifting magnet's suction surface is located at the top, and at the bottom. The reference excitation current is divided into four patterns: a pattern located in the center, a pattern located in the middle, and a pattern in which all narrow steel plates are used, and the corrected excitation current is obtained for each of these patterns, and the reference excitation current is corrected according to the pattern. 1. The method for controlling the number of suspended steel plates according to 1.