Moving Parts - Representing Moving Parts in Engineering Diagrams

Representing Moving Parts in Engineering Diagrams

In technical drawing, moving parts are, conventionally, designated by drawing the solid outline of the part in its main or initial position, with an added outline of the part in a secondary, moved, position drawn with a phantom line (a line comprising "dot-dot-dash" sequences of two short and one long line segments) outline. These conventions are enshrined in several standards from the American National Standards Institute and the American Society of Mechanical Engineers, including ASME Y14.2M published in 1979.

In recent decades, the use of animation has become more practical and widespread in technical and engineering diagrams for the illustration of the motions of moving parts. Animation represents moving parts more clearly and enables them and their motions to be more readily visualized. Furthermore, computer aided design tools allow the motions of moving parts to be simulated, allowing machine designers to determine, for example, whether the moving parts in a given design would obstruct one another's motion or collide by simple visual inspection of the (animated) computer model rather than by the designer performing a numerical analysis directly.