2.1 Basic Concepts of Mechanisms(9) * Kinematic chain(运动链): an assemblage of links and joints. If these links are connected in such a way that no motion is possible a locked chain(structure) result Mechanisn(机构): a kinematic chain in which at lease one link has been grounded",or attached to the frame of reference which itself may be in motion) the links in the kinematic chain move upon each other with definite relative motion Machine (NL ap): a combination of resistant bodies arranged to compel the mechanical forces of nature to do work accompanied by determinate motion*Kinematic Chain（运动链）: an assemblage of links and joints. If these links are connected in such a way that no motion is possible, a locked chain(structure) result. Mechanism（机构）: a kinematic chain in which at lease one link has been “grounded”, or attached, to the frame of reference(which itself may be in motion); the links in the kinematic chain move upon each other with definite relative motion. Machine（机器）: a combination of resistant bodies arranged to compel the mechanical forces of nature to do work accompanied by determinate motion. 2.1Basic Concepts of Mechanisms(9)