Actuator

A valve for controlling pressurized air flow to an inflatable air cell in a vehicle seat, the valve comprising:

• a valve chamber communicating with a spigot and having a valve chamber opening,
• a valve piston which is movable between a position in abutment on a valve seat around the valve chamber opening and a retracted position pulled away from the valve seat to open the valve chamber opening, and
• an actuator comprising:
• a sliding body moveable along a guide between a rest position and a retracted position,
• a spring resting on a support body and acting on the sliding body to exert a bias force urging the sliding body to the rest position, and
• a SMA wire having opposite ends being mechanically and electrically connected to a respective one of two stationary contacts and forming a loop between the opposite ends which is connected to the sliding body, wherein the SMA wire is arranged to, when activated by electric energy supply, pull the sliding body away from the rest position to the retracted position,
• wherein the guide is fixed to a first end portion of an elongated mounting bar, the support body is fixed to an intermediate portion of the elongated mounting bar, and a contact holding body in which the two contacts are incorporated is fixed to a second end portion, opposite to the first end portion, of the elongated mounting bar,
• wherein the sliding body of the actuator is coupled to the valve piston such that, upon activation of the actuator by electric energy supply to the SMA wire, the valve piston is pulled away from the position in abutment on the valve seat by movement of the sliding body from the rest position to the retracted position,
• wherein an end portion of the sliding body, facing towards the support body, is provided with a stud extending in a direction parallel to a longitudinal direction of the elongated mounting bar towards the intermediate portion thereof, the stud being arranged to be received in an interior of the spring, which is formed as a helical compression spring,
• and wherein the stud is provided with a frustoconical outer end portion, and the support body has a socket arranged to receive the stud.

An actuator comprising:

• a sliding body moveable along a guide between a rest position and a retracted position,
• a spring resting on a support body and acting on the sliding body to exert a bias force urging the sliding body to the rest position, and
• a SMA wire having two opposite ends being mechanically and electrically connected to a respective one of two stationary contacts and forming a loop between the opposite ends which is connected to the sliding body, wherein the SMA wire is arranged to, when activated by electric energy supply, pull the sliding body away from the rest position to the retracted position,
• wherein the guide is fixed to a first end portion of an elongated mounting bar, the support body is fixed to an intermediate portion of the elongated mounting bar, and a contact holding body, in which the two contacts are incorporated, is fixed to a second end portion, opposite to the first end portion, of the elongated mounting bar, and wherein the SMA wire is arranged to extend from a first one of the two stationary contacts along the elongated mounting bar to a first connector which is incorporated in the sliding body and to which the SMA wire is connected, from there extends to turn around in a 180 degrees curve to a second connector which is incorporated in the sliding body next to the first connector and to which the SMA wire is connected, and from there back along the elongated mounting bar to a second one of the two stationary contacts.