US Patent 10415681 Linear actuator

A linear actuator that includes a torque generator, a lead screw, a driven nut, an activation circuit and a push rod. The torque generator has an output shaft. The lead screw is operationally coupled to the output shaft of the torque generator. The driven nut has an internally threaded bore that threadably engages external threads of the lead screw in such a manner that frictional forces between the internal threaded bore and the external threads prevent movement between the driven nut and the lead screw when no torque is provided by the torque generator. The activation circuit is in communication with the torque generator. The activation circuit has at least one switch that is configured to be activated by the driven nut. The push rod is operationally coupled to the driven nut.