Showing posts from July, 2020

What is COUPLING in mechanical engineering - ITI ONLINE NOTE

 Couplings  1- Shaft transportation problem are usually available up to 7 meters length more length causes as. 2- To have greater length, it is necessary to join two or more pieces of shafts by means of couplings . 3- Connect the ends of two shafts together.  4- Transmit power from one shaft to other shaft.  5- Reduce the vibrations.  6- Provide mechanical flexibility. 7- Permit misalignment of shafts. Requirements of couplings  1- It should be easy to connect or disconnect.  2- It should transmit full power of shaft. 3- It should hold the shafts in perfect alignment.  4- It should have no projecting parts.  Types of couplings  1- Rigid Couplings . 2- Flexible Couplings . Rigid couplings  1- It is used to connect two shafts which are perfectly aligned.  Types of rigid couplings  1- Sleeve or muff coupling .  2- Clamp or split muff couplings .  3- Flange coupling.   > Protected type . > Un protected type . > Marine type  Sleeve or muff coupling 1- Sleeve or muff coupling is th


LUBRICANT-COOLANT-LUBRICATION i)- With the movement of two mating parts of the machine, heat is generated.  ii)- If it is not controlled the temperature may rise resulting in total damage of the mating parts.  iii)- Therefore a film of cooling medium with high viscocity is applied between the mating parts which is known as a ‘ lubricant ’. iv)- A ‘ lubricant ’ is a substance having an oily property is available.  v)- The property available in the form of fluid, semi-fluid, or solid state.  vi)- lubricant is the lifeblood of the machine. vii)- It is keeping the vital parts in perfect condition and prolonging the life of the machine.  viii)- It saves the machine and its parts from corrosion, wear and tear, and it minimizes friction. Purposes of using lubricants:- 1)- Reduces friction. 2)- Prevents wear. 3)- Prevents adhesion. 4)- Aids in distributing the load. 5)- Cools the moving elements. 6)- Prevents corrosion. 7)- Improves machine efficiency. Properties of lubricants a)- Viscosity, b


INTRODUCTION OF FASTENERS i)- All big or small machines are made by joining different parts.  ii)- There are so many methods to assemble the machines parts with each other these are called fasteners.  iii)- The process by which these are assembled is called fastening.  iv)- There are three main methods of fastening: (a) Temporary fastening , (b) Semi-permanent fastening , (c) Permanent fastening (a) Temporary Fastening :  i)- This is a type of fastening by which different parts of machine can be opened or re-assembled without any damage.  ii)- In this neither job nor fastener is damaged like nut and bolt, key, screw and pin etc. (b) Semi-permanent Fastening:   i)- In this method there is no risk of damage to job but fastener is damaged.  ii)- This system is used where there is a chance of opening of the parts due to some reason, For example soldering and riveting etc is Semi-permanent Fastener. (c) Permanent Fastening:  i)- This is a such type of fastener which becomes part of a mac


WORK-POWER-ENERGY 1. WORK i)- Work is said to be done by a force ii)- When its point of application moves in its own direction and is measured by the product of the force and the displacement of the force in its own direction. iii)- The work is measured by the product of the force applied and the distance through which the body is displaced. iv)- Applied force ‘F’ moves a body through a distance’s. Work done = Force Applied x Distance Moved. 2. UNITS OF WORK i)- Units of work are the combined units of force and displacement.  ii)- Force may be expressed in absolute as well as practical units. iii)- Absolute units of work are  joule . iv)- The S.I. unit of work is 1 joule which is the work done by a force of moving the body through a distance of 1 metre.  v)- Therefore joule = 1 N x 1 metre = 1 N.m( 1 joule) 1)- 1 dyne x 1 cm = 1 erg 2)- 1 newton x 1 metre= 1 joule 3)- 1 foot x 1 Pound = 1 foot Pound 4)- 1 gram x 1 cm = = 1 gram cm 5)- 1 kg x 1 metre = 1 kg metre 6)- 1 foot x 1 pou


What is screw thread? i)- A screw thread is a rigid of uniform section formed helical on the surface of a cylindrical body. ii)- An external screw thread is formed on the outer surface of cylindrical part. for example:- Bolts, Screws, Studs, Threaded spindles etc. iii)- An internal screw thread is formed on the inner surface of a hollow cylindrical part. for example:- Nuts, Threaded lids etc. iv)- External thread and internal threads are assembled together for different engineering uses. Use of Screw Threw


Prevention of corrosion i)- Rusting is in its simplest form, allowing it to eat away from iron at a slow pace. ii)- Corrosion is similar to rust, but is used only to describe the corrosion of iron and its alloys. iii)- Corrosion is a chemical process in which iron reacts with oxygen in the presence of moisture or water to produce Ferris oxide and hydroxide (called corrosion). iv)- Rusting causes slow corrosion of iron and its alloys. This results in material weakening and eventual failure.


INTRODUCTION OF POWER TRANSMISSION:- i)- To start small or big machines some type of power is required like electric motor and engine etc.  ii)- This power produces a rotational energy and to transfer this rotational energy from one place to another place . iii)- It is a different accessories are required like pulleys, belts, chains and gears, etc. iv)- The process of transfer of energy from one place to another place or from one device to another device is known as power transmission.  v)- We know that energy can be produced by running electric motor, oil or steam engine etc.  vi)- With that energy a machine or shaft can be operated. vii)- In this system to move the shaft slow or fast different shape of small and big diameter pulleys or gears are fitted with this to pulley or gear. viii)- motor shaft is called driver pulley or prime mover. The pulley rotated by driver pulley with the help of rope or belt is called driven pulleys or follower.  ix)- The direction of


TAP i)- Tap are used for internal threading propose used.  ii)- They are made from high carbon steel or high speed steel. iii)- Threads are cut on the surface, and are accurately finished.


SPEED & VELOCITY REST:- i)- The body occupies the same position with respect to its surroundings at all moments. The body is said to be called at REST.  MOTION:- i)- The body it change its position with respect to its surroundings the body is said to be called at MOTION.   ii)- The body motion may be moves in a straight line or it may be circular when it moves in a curved path. 


SHEET METAL  i)- Sheet metal is any metal such as iron,steel,aluminium,copper,brass,tin plates etc. ii)- It can be easily rolled in to thin sheet. iii)- A wire gauge is used to measure the thickness of sheet.