Kinematic Link and classification of kinematic links of mechanism.

All the rigid bodies forming the network of a machine are called “links”, Thus, crank, sliding block, rocker arm, connecting link and the ram are the links of a shaping machine.

Let us consider the connecting rod of an internal combustion engine where its big end connected to the crank pin and die small end to the piston pin. Since, it is not our interest to study the shape of a connecting rod, but its two ends represented as small circles.

These ends of the connecting rod which are connected to neighbouring links of the mechanism are its elements.

Classification of Kinematic Links of a Mechanism.

The part of a machine which moves relative to other part is called kinematic link. The different types

1. Rigid Link:-
A link which does not undergo any deformation while transmitting the motion is called rigid link. In actual practice there Is no rigid link. But when the deformation of link is not appreciable then they can be treated as rigid link.

  • The shape or size never changes

Examples: Connecting rod, crank of a reciprocating engine.

2.Flexible link:-
A link which deforms partly without effecting the transmission of motion is called flexible link.The dimensions are changed upto a certain limit.

In flexible link we have one tight side and slack side(loose). So that it deforms partly upto certain limit(permissible limit).
Examples:- Ropes, belts, chains, wires etc.

3. Fluid Link:-
This link is formed by a fluid in a closed vessel. The motion is transmitted through the fluid by pressing only.

  • It is formed by having the fluid and motion is transmitted through the fluid by applying pressure or compression.
  • when the fluid is applied with some force the weight on the other side is lifted.
  • With this more weight can be lifted by applying less force.

Examples: Hydraulic jack, hydraulic press, fluid brakes are examples of fluid link

Floating Link:-
A link which is not connected to the frame is called floating link