2.1Basic Concepts of Mechanisms(2) ink(构件) is a rigid body which possesses at lease two nodes which are points for attachment to other links Ternary link nodes nodes Binary link Quaternary linkLink（构件）:is a rigid body which possesses at lease two nodes which are points for attachment to other links. nodes Ternary link Binary link Quaternary link nodes 2.1Basic Concepts of Mechanisms(2)