ASSIGNMENT
MECHANICS OF MACHINES
➢SUBMITTED BY: ADIL SHAHBAZ
➢REGISTRATION NO: 2016-IM-113
➢SUBMITTED TO: SIR QASIM ALI RANJA
UNIVERSITY OF ENGINEERING AND TECHNOLOGY, LAHORE
(RCET Campus Gujranwala)
DEPARTMENT OF INDUSTRIAL AND MANUFACTURING ENGINEERING
ADIL SHAHBAZ (2016-IM-113)
1
FOUR BAR MECHANISM
The Simplest Mechanism built by using four element is called as four bar chain or four bar mechanism.
INVERSION:
The process of forming different mechanisms from a single chain by altering the fixed link (i.e., unfixing
the base link and fixing another).
Four bar mechanism with its three inversions are shown in this figure below:
INVERSIONS OF FOUR BAR MECHANISM:
1) CRANK ROCKER MECHANISM (BEAM ENGINE):
PURPOSE:
To Convert the rotatory motion to the reciprocating motion.
WORKING:
This is a part of the mechanism of a beam engine this is also known as Crank and liver
mechanism, which consist of four links, in this mechanism when the Crank rotates about a fixed
ADIL SHAHBAZ (2016-IM-113)
2
center A , the liver osillates about a fixed center D the end E of the liver CDE is connected to the
position rod which reciprocates due to the rotation of the crank.
Applications:
➢ WindSheild wipers
➢ Shaping Machine
2) DOUBLE CRANK MECHANISM(COUPLING ROD OF A LOCOMOTIVE):
PURPOSE:
This is used to transfer the rotary motion from one wheel to another wheel.
WORKING:
The mechanism of a locomotive which consist of four links, in this mechanism the link AB and BC act
as Crank and are connected to the respective wheels .In this the coupling rod link CD and the link AB
is fixed in order to maintain a consist center to center distance between them.
ADIL SHAHBAZ (2016-IM-113)
3
Applications:
➢ Coupling rod of locomotive
➢ Dwell Machines
3) DOUBLE ROCKER MECHASNISM(WATT’S INDICATOR MECHANISM):
WORKING:
A WATT'S indicator mechanism which consist of four links, the four links are A, AC, CE and BFD. The
displacement of the link BFD is directly proportional to the pressure of gas or steam which acts on
the indicator plunger. The full lines is shown as the initial position of the mechanism , in this the
dotted lines are shows as the position of the mechanism when the gas or steam pressure acts on the
indicator plunger.
Applications:
➢ Used in automobiles for steering the vehicle to change direction of movement of vehicle.
➢ Gear lever mechanism
ADIL SHAHBAZ (2016-IM-113)
4