# Difference Between Kinematic Pair and Kinematic Chain

## Difference Between Kinematic Pair and Kinematic Chain

Comparison between Kinematic Pair and Kinematic Chain

### Summary:

The Major Difference Between Kinematic Pair and Kinematic Chain that, In Kinematic Pair Two elements connected together. Whereas in Kinematic Chain Four or more than four elements connected together.

### Comparison Chart

Kinematic Pair Kinematic Chain
Two elements connected together Four or more than four elements connected together
Have constrained relative motion with respect to each other The motion of any point on the link with respect to any other point follows a definite direction
Each pair has two links The chain has a minimum of four links. The first link and last link are connected to form a closed chain
Kinematic pair is a part of the chain. Kinematic Chain is not a part of the Kinematic pair.
Examples: Cylinder and Piston, Crank and connecting rod and Piston and connecting rod Examples: Four bar chain, Slider crank chain, and Double crank chain

### Kinematic Pair

• The two links or elements of a machine, when in contact with each other, are said to form a pair.
• If the relative motion between them is completely or successfully constrained (i.e. in a definite direction), the pair is known as kinematic pair.

### Kinematic Chain

• When the kinematic pairs are coupled in such a way that the last link is joined to the first link to transmit definite motion (i.e. completely or successfully constrained motion), it is called a kinematic chain.
• In other words, a kinematic chain may be defined as a combination of kinematic pairs, joined in such a way that each link forms a part of two pairs and the relative motion between the links or elements is completely or successfully constrained.
• For example, the crankshaft of an engine forms a kinematic pair with the bearings which are fixed in a pair, the connecting rod with the crank forms a second kinematic pair, the piston with the connecting rod forms a third pair and the piston with the cylinder forms the fourth pair. The total combination of these links is a kinematic chain.