What is a Mechanism???

Mechanisms are nothing but arrangement of links(rigid bodies) which are connected by joints (collectively called as linkages) in an orderly manner so that a particular required function is done.(to know about links:http://daytodaymechas.blogspot.com/2013/06/what-are-kinematic-links-and-it-types.html)


Let us try to understand what is mechanism using few examples

1.A 2 bar open loop mechanism

A 2 bar open loop mechanism - Mainly used for robotics arms. (Created using SolidWorks)

 This is called as  2 bar open loop mechanism. It is called so because it has two links and a connected by a joint(which satisfies basic definition of a mechanism). Only one link is grounded so this a open loop mechanism. This can be used as an robotic arm that can write or pick up things by connecting servo motors(or any actuators) in each joints.

2.Closed Loop 4 bar mechanism

A closed loop 4 bar mechanism - Rotational input is given to the input link(Created using SolidWorks)

The output link rotates because of the input motion(Created using SolidWorks)

The above diagram represents a closed loop four bar mechanism. This is called as closed loop mechanism because all the links are so connected to for a closed chain. Here the left most link acts as input links and the right most link acts as output. 4 bar mechanisms are used in many places like car suspension, waste dumper truck etc. Modification of 4 bar mechanism is also used in many applications.

4 bar mechanism is car suspension system