Answer:
The planer four bar linkage is the type of closed chain linkage and it is also simple movable linkage system. It is also known as "four-bar" linkage.
In this type of four bar linkage the re-volute joints are mainly designed to handle the transverse load easily as compared to load acting on the length of the link.
The planer four bar linkage are mainly constructed when the four types of links are mainly constructed in the loop format by using the joints. These joints are basically configure so that the links can easily move in the parallel plane system.