2.1 Basic Concepts of Mechanisms 3) Joint(铰链或运动副) Joint: is a connection between two or more links(at their nodes), which allows some motion, or potential motion, between the connected links Joints(also called kinematic pairs) can be classified in several ways By the type of contact between the elements, line, point, or surface 2. By the number of degree of freedom allowed at the joint OthersJoint: is a connection between two or more links(at their nodes), which allows some motion, or potential motion, between the connected links. Joints (also called kinematic pairs) can be classified in several ways: 1. By the type of contact between the elements, line, point, or surface. 2. By the number of degree of freedom allowed at the joint. 3. Others 2.1Basic Concepts of Mechanisms(3) Joint (铰链或运动副)