FLYWHEEL

Flywheel=> "A flywheel is an inertial energy-storage device. It absorbs mechanical energy and serves as a reservoir, storing energy during the period when the supply of energy is more than the requirement and releases it during the period when the requirement of energy is more than the supply".

Fly wheel of an i.c engine

The main function of a fly wheel is to smoothen out

Screw jack assembly

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MECHANICAL GEARS IN NATURE

PREVIOUSLY IT IS BELIEVED TO BE ONLY MAN-MADE GEAR MECHANISM IS PRESENT. BUT RECENTLY A NATURAL EXAMPLE OF GEAR MECHANISM HAS BEEN DISCOVERED IN A COMMON PLANT-HOPPING INSECT FOUND IN GARDENS ACROSS EUROPE.

This insect has hind-leg joints with curved cog-like strips of opposing ‘teeth’ that intermesh, rotating like mechanical gears to synchronize the animal’s legs when it launches into a jump.

Each gear tooth has a rounded corner at the point it connects to the gear strip; a feature identical to man-made gears such as bike gears – essentially a shock-absorbing mechanism to stop teeth from shearing off. 

The gear teeth on the opposing hind-legs lock together like those in a car gear-box, ensuring almost complete synchronicity in leg movement - the legs always move within 30 ‘microseconds’ of each other, with one microsecond equal to a millionth of a second.

Insect gears closer view

“These gears are not designed; they are evolved - representing high speed and precision machinery evolved for synchronisation in the animal world.”

PTU'S PREVIOS YEAR QUESTION PAPERS

New tab is added on the blog with the name of PTU  PREVIOUS YEAR QUESTION PAPERS .
Here you find the previous year question papers of ptu in pdf document. the question papers are added semester wise and subject wise. you can download zip file of question papers of a subject by clicking on the subject name....
If any error occurs please type it in comments,,,

FOR MORE VISIT REGULAR ON www.ctmechanical.blogspot.com

UNIVERSAL JOINT

Universal joint is considered to be one of the old flexible couplings.A universal joint in its simplest form consists of two shafts yokes at right angles to each other and a four point cross which connects to the yokes. A universal joint can operate at high misalignment angles i.e upto 15 degrees, therefore it is used in for the power transmission in trucks, cars etc.There are various types of universal joints.

A Universal joint

Working animation of universal joint

SPACE SHUTTLE

EMM, Iron carbon diagram video

LATHE MACHINE

Lathe machine is a very common and useful machine.
This machine can perform  various operations like cutting, sanding, knurling, drilling, turning etc on the workpiece .There are various types and sizes of lathe machine according to the type of requirement and work. The parts of all lathe machines are identical to each other with little bit difference..
Basic parts of the lathe machine-

Diagram of lathe machine showing its various parts.

HAPPY INDEPENDENCE DAY TO ALL..........

EME WORKING OF A FOUR STROKE PETROL ENGINE

WORKING OF A FOUR STROKE PETROL ENGINE

In this post we will learn about the working of a four stroke petrol engine.

The working of a four stroke petrol engine is based upon the otto cycle.

A Four stroke petrol engine is consisting of four processes or strokes, i.e 1.Suction,2.Compression,3.Power and 4.exhaust.

1.Suction stroke:- Suction stroke is also called as intake stroke.In suction stroke the air and fuel mixture enters in the cylinder through inlet valve and the  piston moves from TDC to BDC.This stroke completes when the piston reaches at bottom dead centre or outer dead centre. This whole process can be shown on pv. diagram in line 1 to 2.

SUCTION STROKE

2.Compression stroke:- In compression stroke both the valves i.e intake and exhaust valves are closed.in this process the piston returns to the top of the cylinder compressing the air or fuel-air mixture into the combustion chamber of the cylinder head. During the compression stroke the temperature of the air or fuel-air mixture rises by several hundred degrees. This is shown in p.v diagram by the line from 2to3.

COMPRESSION STROKE