US Patent 7178653 Electromagnetic clutch

In an electromagnetic clutch, an electromagnetic coil is energized to couple a rotor and an armature plate to each other. Each leaf spring extends in a direction so as to intersect at an obtuse angle with the rotating direction of the armature plate, and accordingly, when the power of the driving source is transmitted to the armature plate through the rotor, a compressive force acts upon the leaf spring. The leaf spring has an inclined portion, and the armature plate is pressed against the rotor by the compressive force. Each leaf spring has a first extended portion located between the first coupling portion and inclined portion thereof and a second extended portion located between the second coupling portion and inclined portion thereof.