Patent ID: 8487725

Claim:
An electromagnetic contact device, comprising: a case including an extinction chamber, and a contact point portion accommodated in the extinction chamber and having a movable contact point and a fixed contact point; and an extinction cover mated with and mounted on the case for covering the extinction chamber; wherein the extinction cover is mounted on the case to seal the extinction chamber, the extinction cover has an engaging-force-increased portion strengthening an engaging force with the case, and an engaging-force-decreased portion weakening the engaging force with the case, said engaging-force-increased portion comprises two pairs of engaging portions and engaging holes engaging the engaging portions, respectively formed on one side of the extinction cover and the case, said engaging-force-decreased portion comprises one pair of engaging portion and engaging hole engaging the engaging portion, formed on a side opposite to the engaging portions and engaging holes, and in response to an increase in internal pressure in the extinction chamber due to an arc gas generation, the extinction cover disengages from the case at the engaging-force-disengaged portion and provides a gap with respect to the case linking the extinction chamber to external air, and the engaging-force-increased portion maintains engagement with the case.