Four-bar Mechanisms

A four-bar mechanism is a mechanism having four rigid links.
  • The fixed link is called the frame.
  • There is one rotating link called the driver or crank.
  • The other rotating link called the follower or rocker.
  • The fourth is a floating link that does not rotate about a fixed center and is called a connecting rod or coupler.
Drag the point at the end of the crank to operate the mechanism.

Open four-bar mechanism

Crossed four-bar linkage

Parallel four-bar mechanism