ABSTRACT
A screw nut combination converts rotary motion into linear motion, and is used in several recent types of electrically driven linear actuator. The ASEA robot is an example of a lever system in which the upper arm and forearm are driven by screw nut systems, powered by DC motors via harmonic drive gearboxes. This is an interesting arrangement, incorporating several of the motion conversion systems, using rods instead of belts. Cams have been traditional way of obtaining motion profiles in high speed machinery in which large forces need to be generated. Typical applications include textile and printing equipment, shoe making machinery and dedicated machines such as bolt headers. The four-bar linkage may be used to produce special motion profiles by using points on the coupler plane or as a function generator. The Four-bar linkage includes springs and dampers, variators, conical pulley/disc systems, and cone pulley variable belt drive.
