US 12,441,589 B2
Steel plate lifting method with use of lifting magnet, lifting magnet, and method for manufacturing steel plate by using lifting magnet
Yuki Takaki, Tokyo (JP); Yusaku Takemura, Tokyo (JP); Atsushi Kurimoto, Tokyo (JP); and Ayaka Kawai, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 18/275,553
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Dec. 15, 2021, PCT No. PCT/JP2021/046215
§ 371(c)(1), (2) Date Aug. 2, 2023,
PCT Pub. No. WO2022/180993, PCT Pub. Date Sep. 1, 2022.
Claims priority of application No. 2021-031240 (JP), filed on Feb. 26, 2021.
Prior Publication US 2024/0101396 A1, Mar. 28, 2024
Int. Cl. B66C 1/08 (2006.01)
CPC B66C 1/08 (2013.01) 10 Claims
OG exemplary drawing
 
1. A steel plate lifting method for using a lifting magnet configured to lift at least one steel plate to be lifted from among a plurality of stacked steel plates, the lifting magnet including a plurality of electromagnet coils that are each independently ON/OFF controllable and voltage-controllable, a magnetic pole that is excited by application of a voltage to the electromagnet coils, a control device that controls to lift the at least one steel plate, a magnetic flux sensor that measures an amount of passing magnetic flux pa in the magnetic pole, and a weight measurement means that measures the weight of the at least one steel plate that is lifted, and the steel plate lifting method comprising:
determining, based on a total thickness of the at least one steel plate to be lifted, an electromagnet coil to be used for lifting the at least one steel plate;
calculating an amount of passing magnetic flux Φr in the magnetic pole in a case where magnetic flux flowing out of the magnetic pole passes through only the at least one steel plate to be lifted when the electromagnet coil is used;
determining an application voltage to be applied to the electromagnet coil used for lifting the at least one steel plate, based on the amount of passing magnetic flux Φr;
applying the application voltage to the electromagnet coil to lift only the at least one steel plate to be lifted from among the plurality of stacked steel plates; and
checking, by the control device, whether or not the number of the at least one steel plate lifted matches the number of the at least one steel plate determined to be lifted in advance by determining whether or not a difference between the calculated amount of passing magnetic flux Φr in the magnetic pole and the measured amount of passing magnetic flux Φa in the magnetic pole is equal to or less than a threshold after applying the application voltage to the electromagnet coil and starting lifting of the at least one steel plate with the lifting magnet before moving the lifting magnet with which the at least one steel plate is lifted, the amount of passing magnetic flux Φr in the magnetic pole being calculated by the control device, and the amount of passing magnetic flux Φa in the magnetic pole being measured by the magnetic flux sensor,
wherein when the difference is equal to or less than the threshold and the number of the at least one steel plate lifted matches the number of the at least one steel plate determined to be lifted in advance, the control device further checks whether or not the number of the at least one steel plate lifted matches the number of the at least one steel plate determined to be lifted in advance, based on the weight of the at least one steel plate measured by the weight measurement means.