ELECTRIC ACTUATORS

摘要

An electric actuator having an output member movable from a first variable position to a second variable position; an electric motor operable to control a spring system to exert an output force on the output member when in its second position; means for generating an electrical signal when the output member is about to leave the second position as it returns to the first position; and a motor-control electrical circuit which recognises the generation of the electrical signal and thereafter operates the electric motor to a pre-determined degree to move the output member a corresponding predetermined distance back to the first position so that there is preserved a substantially constant distance between the first and second positions.