KINEMATIC PAIR- RELATIVE MOTION

On the basis of nature of relative motion kinematic pairs can be classified as:
* Sliding Pair
* Turning Pair
* Rolling Pair
* Helical Pair
* Spherical Pair

Sliding Pair
If two links have sliding motion relative to each other.
Example:
A rectangular rod in a rectangular hole

Turning Pair
When one link has a revolving motion relative to other.
Example:
Circular shaft revolving inside a bearing

Rolling Pair
If links of pair have rolling motion relative to each other.
Example:
Ball and roller bearings

Helical Pair (Screw Pair)
When the links of a pair have turning as well as sliding motion.
Example:
nut-bolt

Spherical Pair
If one of the two links is spherical and it turns inside the other.
Example:
Ball and socket joint