In mechanical engineering, a kinematic chain is an assembly of rigid bodies connected by joints to provide constrained motion that is the mathematical model for a mechanical system. As the word chain
The JPL mobile robot ATHLETE is a platform with six serial chain legs ending in wheels.
The arms, fingers, and head of the JSC Robonaut are modeled as kinematic chains.
A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage to multiply force.
Kinematic chain
…Six-bar linkage Simple machines Six degrees of freedom…
The screw's self-locking property is the reason for its wide use in threaded fasteners like bolts and wood screws
Illustration of a four-bar linkage from Kinematics of Machinery, 1876