Abstract: An actuation device comprising:at least two thermal actuators (5A,5B) electrically supplied, each thermal actuator (5A,5B) comprising relevant thrust means (4A,6A,4B,6B) being movable to perform a predetermined stroke;at least a working means (12) moved by means of said thermal actuators (5A,5B) and connected with the thrust means (4B,6B) of one of said thermal actuators (5A,5B);where said working means (12;12A;18) is able to take at least three different steady working positions (I,II,III) in function of the presence of supply to a first (5B) or a second (5A) or both said thermal actuators (5A,5B).According to the invention, said first thermal actuator (5B) is free to move with respect to said second thermal actuator (5A) and means (6A,11) are provided for transferring the thrust produced by the second thermal actuator (5A) to the first thermal actuator (5B), and causing a change in the reciprocal positioning of one thermal actuator with respect to the other.

Abstract: Such switches have current connections for contacts. One contact may be a fixed contact and the other contact may be a mobile contact. A drive opens the mobile contact when a predetermined electric current intensity is exceeded. The electric drive is a thermoelectric drive. For that purpose, the contacts (2,3) are arranged in a closed housing (1) made of an insulating material and a disk-shaped resistive member (4) is arranged between the contacts (2,3). A switch of this type may also be advantageously designed as a bistable limiter.

Abstract: An actuator device varies its functional condition from a state of rest to a working state, both stable and has a body receiving a thermal actuator, an electric heater, electric contacting elements and a transmission shaft for the thrust generated by the actuator. A bistable kinematic mechanism uses inclined planes and/or cams.