Patent ID: 8237536

Claim:
A thermal protector, comprising: a pair of terminals for connection with an external circuit, the pair of terminals located in a conduction area; a pair of fixed contacts constituting a switch part of an electric circuit formed in the pair of terminals, the pair of fixed contacts located in an overlapping portion of the conduction area; a movable plate composed of an elastic plate provided with a single movable contact at a first end of the movable plate, the single movable contact located in the overlapping portion and opposed to the pair of fixed contacts, the moveable plate operable for generating a prescribed contact pressure to the pair of fixed contacts by urging the single movable contact to directly contact each of the pair of fixed contacts, the pair of fixed contacts are operable to electrically insulate the pair of terminals when the single movable contact is not in direct contact with the pair of fixed contacts, and are operable to electrically conductively couple the pair of terminals when the single movable contact is in direct contact with the pair of fixed contacts; and a bimetal element engaged with the movable plate, the bimetal element being inverted in a direction of bending backward at a prescribed temperature so that the bimetal element drives the movable plate to switch on/off the pair of fixed contacts via the single movable contact, wherein the movable plate is disposed in a direction so that a second end of the movable plate distal to the first end of the movable plate extends away from the fixed contacts and extends beyond the conduction area and extends beyond the overlapping portion in a direction that is different from and not adjacent to the conduction area, wherein Joule heating generated in the conduction path is directly conveyed from the movable contact to the movable plate and bimetal element is never received from the conduction path by radiation and convection, and the bimetal element is structured in such a way that a first end of the bimetal element is engaged with the first end of the movable plate provided with the single movable contact, and a second end of the bimetal element is engaged with the second end of the movable plate and wherein an overlap ratio of an inversion area of the bimetal element to the conduction area is equal to ⅓ or less.