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Sliding pair :

When the two elements of a pair are connected in such a way that one can only slide relative to the other, the pair is known as a sliding pair. The piston and cylinder, cross-head and guides of a reciprocating steam engine, ram and its guides in shaper, tail stock on the lathe bed etc. are the examples of a sliding pair. A little consideration will show that a sliding pair has a completely constrained motion.

Inversions of Double Slider Crank Chain :

1. Elliptical trammels.

2. Scotch yoke mechanism.

3. Oldham’s coupling.

When one of the links is fixed in a kinematic chain, it is called a mechanism. So we can obtain as many mechanisms as the number of links in a kinematic chain by fixing, in turn, different links in a kinematic chain. This method of obtaining different mechanisms by fixing different links in a kinematic chain is known as inversion of the mechanism.

Quick return mechanism

Applications:

An Oldham's coupling is used for connecting two parallel shafts whose axes are at a small distance apart.

Used to transmit motion and power.

Types of Constrained Motions :

Following are the three types of constrained motions:

Inversions of double slider crank chain:
i.Scotch Yoke mechanism.
ii.Oldham’s coupling.
iii. Elliptical trammel.