Kinematic Pair:
It has two element or link joined together which have relative motion between them. The motion between the link is completely or successfully constrained.
Classification of Kinematic Pair :
1. Types of contact
2. Type of constraint
3. Type of relative motion
1. Types of contact
Lower Pair :
If pair in motion has a surface/Area contact between its element it is called a lower pair.
Example: shaft rotating in bearing, piston reciprocating in a cylinder.
Higher Pair :
If pair in motion has a line or point contact between its element it is called a higher pair.
Example: Cam and follower ball and roller bearing Shaft rolling on a Flat Surface.
2. Types of constraint
Closed Pair :
If the element of the pair are held together called closed pair.
Example: mechanically, they All lower pairs
Unclosed Pair :
If the element of the pair are not held together mechanically, they called unclosed pair.
Example: Cam and follower pairs.
3. Types of Relative motion:
Sliding Pair :
The two element have a sliding motion relative to each other.
Example: Piston and cylinder.
TurningPair :
The two element connected suchatrheat one element revolve around the other.
Example: Piston and cylinder
Rolling Pair :
When one element is free to roll on other, it form the rolling pair.
Example: Motion of wheel on surface.
Screw Pair :
In this type of pair the contacting surface are having thread. This is also known as helical pair.
Example: A bolt and nut arrangement, Screw jack.
Spherical Pair :
When one link in the form of a sphere turns inside a fixed link, it is a Spherical Pair.
Example:Ball and Socket Joint.
