Motor actuator for centrally operated vehicular door latch

In combination with a door latch having

• a threaded spindle;
• a nut threaded on the spindle and axially displaceable thereby on rotation of the spindle;
• an input gear carried on and rotatable with the threaded spindle;
• and
• a coupling element connected to the nut and displaceable thereby to lock and unlock the latch, a power actuator comprising:
• a reversible electric motor having an output shaft defining a main axis and rotatable by the motor in either direction thereabout;
• an input wheel fixed on the output shaft and provided with an eccentric coupling pin;
• an intermediate wheel juxtaposed with the input wheel, rotatable relative thereto about the main axis, and provided with an eccentric pivot;
• an output wheel rotatable about the main axis, having a gear continuously meshing with the input gear of the threaded spindle, and provided with a pair of angularly offset abutments defining an orbit on rotation of the output wheel about the main axis;
• a coupling element mounted on the intermediate-wheel pivot, provided with respective angularly offset coupling formations engageable with the output-wheel abutments, and having a formation angularly engaging the input-wheel coupling pin;
• and
• means including a spring for urging the coupling element into a rest position with the coupling formations inside the orbit and the input wheel decoupled from the output wheel, the coupling element being movable angularly against a force of the spring about the eccentric pivot on rotation of the input wheel relative to the intermediate wheel to end coupling positions in each of which a respective one of the coupling formations engages the respective abutment and couples the input wheel to the output wheel for joint rotation about the axis.