Switch having a safety element

A switch having a first and at least a second external terminal, and a temperature-dependent switching mechanism that makes, as a function of its temperature, an electrically conductive connection between the first and second external terminals, the switching mechanism comprising a switching member which changes its geometrical shape between a closed position and an open position as a function of temperature and, in its closed position, carries the current flowing through the switch, and an actuating member which is permanently connected electrically and mechanically in series with the switching member, wherein the switch comprises a safety element which, when a given safety temperature is exceeded for the first time, keeps the switch in its open condition irrespective of its subsequent temperature, and wherein the actuating member comprises a spring element whose displacing force is largely temperature-independent, and wherein the switching member has a creeping phase and a temperature-dependent displacing force that is higher than the displacing force of the spring element, when the switching member is in the creeping phase.

A switch having a first and at least a second external terminal, and a temperature-dependent switching mechanism that makes, as a function of its temperature, an electrically conductive connection between the first and second external terminals, the switching mechanism comprising a switching member which changes its geometrical shape between a closed position and an open position as a function of temperature and, in its closed position, carries the current flowing through the switch, and an actuating member which is permanently connected electrically and mechanically in series with the switching member, wherein the switch comprises a safety element which, when a given safety temperature is exceeded for the first time, keeps the switch in its open condition irrespective of its subsequent temperature, and wherein the safety element is a compression spring that acts on the actuating member, and wherein the compression spring is in its compressed condition before the safety temperature is exceeded for the first time, and is retained in that position by fusible solder, which liquefies after the safety temperature has been reached so that the compression spring is permitted to relax.