DISPOSITIV DI ARRESTO ANTI GUASTOAPPLICABILE AD ATTUATORI PARTICOLARNTE AD ATTUATORI A IONATI ELETTRICA CAMENTE

摘要

An actuator has a fail-safe mechanism operable by a spring. The spring is normally held inoperable by electrical means so that the fail-safe mechanism is independent of the normal operation of the actuator. The fail-safe mechanism is rendered operative by failure of the electrical supply so that the spring rotates a cam plate which is coupled with the switch plate so as to move the output shaft to a predetermined fail-safe position by the stored energy of the spring force.