# How many inversions are possible for the four bar linkage?

## How many inversions are possible for the four bar linkage?

By fixing each link at a time we get as many mechanisms as the number of links, then each mechanism is called ‘Inversion’ of the original Kinematic Chain. Inversions of four bar chain mechanism: There are three inversions: 1) Beam Engine or Crank and lever mechanism.

**What do you mean by the inversions of kinematic chain?**

Kinematic Inversions • Process of obtaining different mechanisms from the same kinematic chain, by fixing different links in turn, is known as kinematic inversion. • Four inversions are possible from four-bar kinematic chain.

### What is inversion mechanism?

Inversion is the method of obtaining different mechanism from single kinematic chain by fixing different links in turn.

**How is the length of a Grashof linkage determined?**

A Grashof linkage is a planar four-bar linkage with s + l p + q where s = length of the shortest link l = length of longest link p and q are the lengths of the two remaining links. For linkages of this type continous relative motion between the shortest link and its adjacent links is possible.

#### How is Grashof’s law broken into two parts?

By Grashof law, for at least one link to be capable of making a full revolution, the sum of the lengths of the shortest link and the largest link is less than or equal to the sum of the lengths of the other two links. s + l ≤ p + q The condition can be broken into two parts: 1. s + l < p + q 2. s + l = p + q What happens if ‘s + l > p + q’?

**How is the Grashof criterion used in kinematics?**

Grashof Criterion. Grashof’s Criterion (sometimes called Grashof’s Law, Grashof’ Rule, or Grashof’s Criterion) helps predict whether one Part can, or cannot, rotate continuously. The Grashof Criterion is applied to four-bar kinematic-chains that are joined with Pin-Joints.

## How are inversions obtained in a kinematic chain?

In such kinematic chain , the links become collinear atleast once per revolution of input crank. In this case, the inversions obtained are same as in the case S + L < P + Q. which are :- double crank, double rocker and crank rocker.