Patent attributes
A motor-driven actuator extends and retracts a piston rod. The actuator includes a housing, an electric motor having a motor shaft, a piston rod slidably extendable and retractable with respect to the housing, a speed-reduction stage coupled to the motor shaft and rotating a drive shaft parallel to the motor shaft, a speed and direction-change stage coupled to and driven by the drive shaft and rotating a wheel gear substantially perpendicular to the motor shaft, and a driving stage coupled to and driven by the wheel gear and extending and retracting the piston rod relative to the housing along a direction parallel to the motor shaft. The actuator also includes a position detector detecting when the piston rod is in the extended and retracted positions. Preferably, the position detector includes Hall effect sensors and a permanent magnet mounted on a piston driving the piston rod.
