Development of dual mode X-screw: a novel load-sensitive linear actuator with a wide transmission range

X-screw, a load-sensitive linear actuator that we have proposed, has many desirable characteristics, but one drawback is that the linear motion is much slower than a conventional lead screw because of the method X-screw uses to produce linear motion. When the axial load is small, the transmission efficiency of X-screw is approximately the same as that of a lead screw since the transmitted power is low in this case. Therefore we have developed a dual mode version of X-screw called "DM X-screw". This mechanism is able to automatically switch between lead screw mode and X-screw mode in response to the axial load. This feature makes it possible to apply DM X-screw to many mechanical systems. We have used this mechanism in a pantograph jack that makes use of its dual mode load-sensitive variable transmission properties. This jack can be operated with a small input force and unlike conventional jacks, several of these jacks can be used in combination to overcome the output force limitations of normal pantograph jacks.