Manufacturing method of an attraction plate for electromagnetic door locks

A manufacturing method of an attraction plate for electromagnetic door locks, comprising:

• a) providing an electric magnet in a long shape;
• b) providing a mounted body disposed at a corresponding side to the electric magnet with a positioning hole arranged in the middle thereof;
• c) providing an attraction plate with a thickness between 10-16 mm and a length in correspondence to the length of the electric magnet, said attraction plate including an attraction surface at a side facing the electric magnet;
• d) deciding a thickness of the attraction plate to determine a height of an arch portion arranged at the center on the attraction surface, the thickness of the attraction plate being inversely proportional to the height of the arch portion and the height being between 0.04-0.27 mm with the thickness of the attraction plate being between 10-16 mm;
• e) manufacturing the attraction plate according to pre-determined numbers of thickness and height in step d, the attraction plate having two corresponding convex-curve surfaces extending from the arch portion to both ends of the attraction plate, defining the arch portion a higher central region than both ends of the attraction plate;
• f) providing the attraction plate manufactured in steps c-e, which has an engaging hole correspondingly arranged to the positioning hole;
• and
• g) providing a bolt to fixedly screw the engaging hole to the positioning hole for placement of the attraction plate on the mounted body with the attraction surface thereof facing upward, defining both ends thereof as free ends.