## 20 May 2017

### Mechanism and machine

What is the mechanism :

When one of the links of a kinematic link is fixed, then the chain is known as a mechanism.

A mishmash of a number of bodies assembles in such a way that it causes the constrained and predictable motion to the other is known as a mechanism.
Thus, the function of the mechanism is to transmit and modify a motion.

What is a machine :

Machine is a mechanism which receives energy and transforms it into some useful work.

A collection of mechanisms which, transmits and modifies available mechanical energy into some kind of desired work and also imparting definite motions to the parts is called machine.

It is neither a source of energy nor a producer of work that helps in proper utilization of the same. The motive power has to be derived from external sources.

Example :

A slider-crank mechanism converts the reciprocating motion of a slider into rotary motion of the crank or vice-versa. however, when it is used as an automobile engine by adding valve mechanism it is it becomes a machine which converts the available energy into the desired energy.

Some other examples of mechanisms are typewriter, clocks, watches, spring toys etc.

In each of these force or energy provided is not more than what is required to overcome the friction of the path and which is utilized just to get the desired motion of the mechanism not to obtain any useful work.

Some useful notes :

A machine is tangible, but the mechanism is not. Only the effect of the mechanism is observable.

In a simple way, a mechanism is a system that is followed by a machine to achieve the particular function while machine is a combination of tools and parts that performs specific functions at the expense of energy.

For Example :

We think a car is a machine. It made of various mechanisms such as the wipers, piston and crankshaft, differential.
All this parts are simple a mechanism following below :

• Wipers is a 4 link crank lever mechanism
• Piston and crankshaft is a slider crank mechanism
• Differential is a gear mechanism.

Thus a machine is made of number of mechanism to carryout a particular task.