PURPOSE: To strengthen opening force of a movable contact, to improve yield strength against slightest fusion of a contact, to increase the opening speed, to extend the service lives of movable and fixed contacts, and to make the contacts usable for high electric power by installing a back up spring in a movable contact spring.
CONSTITUTION: When electric current is applied to an electromagnet 4 and a core 4d draws an armature 15, a movable contact spring 8 bends left through a card 16 and a movable contact 5b parts from a fixed contact 11 and starts to have a contact with a fixed contact 12, and while the contacting force of a movable contact 5a becomes high, the tip part of a back up spring 22 comes to the middle part of the spring 8 and finally the armature 15 comes to have a touch with the core 4d and thus driving operation ends. Then, when electric current to the electromagnet 4 is stopped, the spring 8 together with the springs 22 returns to the original state with strong parting force and the contact 5a is parted from the contact 12 and the contactor 5b has a touch with the contact 11. The parting force can be increased to 28 g from 20g, and fusion of the contacts is hardly caused and consequently long service lives and high capacity are achieved.
HANADA HIROTSUGU
MATSUNO KESAFUMI
