DEVICE FOR HEAT PROTECTION OF ELECTRIC APPLIANCE AGAINST OVER-HEATING Russian patent published in 1997 - IPC

FIELD: electric engineering. SUBSTANCE: device has housing, first and second fixed contacts which have constant space between them and are located on plate which does not conduct heat and electric current. Said contacts are connected in overlapping to third spring-loaded contact by means of fusible material which fusion temperature is equal to temperature for switching heating appliance off. Said first and second fixed contacts have vertical terminals. Fusible current-conducting material is inserted between contacting planes of two fixed and third contact. Latter contact is spaced from vertical terminal of second fixed contact by distance which is greater than overlap of third contact and first fixed contact. Third contact is connected to first end of cylindrical spring which another end is connected to vertical terminal of second fixed contact. Point of connection is spaced from terminal by half of outer diameter of spring. It is mounted for rotation around axis which runs through connection point of second end of spring in parallel to opposite sides of fixed contacts. Spring axis is shifted from vertical direction by angle which conforms to equation , where β is angle between spring axis and vertical direction, a is length of contact overlap of third and first fixed contact, H is distance between connection point of second end of spring with respect to upper plane of second fixed contact. In addition housing may have bottom which is made from material which conducts heat, and vertical wall. In this case plates are fixed between housing and bottom, while vertical wall presses first fixed contact to it. EFFECT: increased functional capabilities. 2 cl, 1 dwg