The reciprocating screw is a form of three-dimensional cam pair, which is characterized by two threaded grooves with the same pitch but opposite rotation direction. Connect both ends with transition curves. By rotating the screw, the sliding block placed inside the spiral groove is pushed back and forth axially by the side of the spiral groove.

The application scope of reciprocating screws includes: robots, CNC machine tools, conveyors, aircraft components (such as ailerons), medical equipment (such as X-ray equipment), and printing machinery (such as offset printing machines), and so on.