This document outlines a student project to design and build a quick return mechanism. It will involve researching quick return devices, developing a mathematical model, and implementing the design. The project plan includes background research, proposing a design, performing analysis in software, fabrication, and testing. The timeline stretches from July to March. The methodology incorporates designing links, analyzing positions, modifying if needed, implementing, fabricating, and testing performance. References are provided to guide the design process.

1. PROJECT SEMINAR
PROJECT GUIDE: D.SRINIVAS RAO (ASSOCIATE HEAD)
BY : MD NASEERUDDIN SHAH 1604-11-736-072
IBRAHIM MD AMEENUDDIN 1604-11-736-075
MOHD JALEELUDDIN 1604-11-736-105
MD SOHAIL KURANI 1604-11-736-135

3.  Introduction
 Basic Concepts
 Defining the Problem
 Overcoming the Problem
 Design
 Analysis
 Fabrication
 Application
 Conclusion
 Project Plan
 Methodology
 Bibliography

4. Quick return mechanism, (QRM), is considered
one of the important mechanisms

5.  Mechanism : It transforms or transfer motion

6.  Link: Machine element which moves relative
to other elements (machine)
a) Rigid link
b) Flexible link
c) Fluid link

7.  Kinematic pair : When two links are joint they
constitute a pair
 Joints : Junction of links
Type of motions possible between links
• Revolute
• Sliding

8. Number of Links : 4
Number of Pairs : 4
Number of Fixed Links : 4

9.  Modification of a basic four bar chain
 It consists of one sliding pair, three turning
pair

10.  Method of obtaining different mechanisms by
fixing different links in a kinematic chain
 No. of Inversions possible = No. of links
 No. of Inversions for four bar mechanism = 4

11.  Pendulum Pump
 Oscillating Cylinder Engine

12.  Rotary Internal Combustion Engine
 Crank and Slotted Lever Quick Return Mechanism

13.  Whitworth Quick Return Mechanism

14. Lower Quick Return Ratio
Vibrations due to non linear velocity
Defining Problem
Rigid structure
Selection of material
Usage of Brass Bearings
Overcoming the problem

15. 1.Forces acting on each link
2.Selecting materials
3.Suitable cross section
4.Link lengths
5.Machine power
 Factors To Be Considered In Design
Design

16. Specifications and Calculations
Stroke =120mm
Q.R =3
No.of strokes/min =50
Length AC = 40mm
Length BC = = = 56.57mm
Length AP = = =84.85mm
Length PR = 20mm

17. Dynamic Analysis
Calculation Of Forces
F6 = Τsteel *d* w
F6 = 225*4*5
F6 = 4500N
F2 = F6
F5 =
F5 =
F5 =6364N
F4 = F5

18. Design of Crank
Maximum force acting on Crank = 4500 * Impact Load Factor
= 4500*2 = 9000N
Cross-sectional Area Of Crank = Max Load / Permissible Stress
= 9000/200 = 45mm2 ………..1
Considering Rectangular Cross-Section, b=2d.
C.S Area = b*d = 2d*d ………..2
Equating 1 and 2
2d*d = 45
d = 5mm
b = 10mm

19. Design Of Slotted Bar
Maximum Force acting on Slotted Bar = 6364 * Impact Load Factor
= 6364*2 = 12728N
Cross-sectional Area Of Crank = Max Load / Permissible Stress
= 12728/200 = 64mm2 ………..1
Considering Rectangular Cross-Section, b=2d.
C.S Area = b*d = 2d*d ………..2
Equating 1 and 2
2d*d = 64
d = 6mm
b = 12mm

20. Power Calculations
From Specifications
Mean Velocity = Stroke length * No. of strokes/mm
= 120*100
= 12 m/min
Power = Cutting Force * Mean Velocity
= 4500*(12/60)
= 900 watts (1.2 HP)
Including Friction and Inertia Forces 2HP Motor is
required.

21. Design For Power Transmission
 RPM of the Crank = No. of Strokes per minute
 To Convert 1400rpm motor motion into 100rpm motion V-Belt drive
 For given loads Phosphor Bronze Bushings of required thickness should
be used at Pin Joints between the links
 Due to large fluctuations in loads Vibrations are induced.
 To minimize these Vibrations, Cast Iron or Wooden Frame should be used

22.  Positional Analysis
 Velocity Analysis
 Acceleration Analysis
 Force Analysis
Analysis of Quick Return
Mechanism

23. Data Acquisition System
 System takes the analog output from the various sensors and
converts them into digital values.
 Digital analogous value is fed into the processing unit.
 The computer uses software called KDM (Kinematics and
Dynamics Of Machines).
The needed values and their characteristic curves are plotted
by the software and the output is recorded.

24. Analysis Softwares
Motion simulation softwares
CAE tools
 Catia
 UG-NX
 NX I-DEAS
 SolidWorks
To study planar mechanism kinematics
 MatLab
 Simulink
 MapleSim
 SolidWorks

25. Software Analysis Procedure
 Modeling the linkage using the motion simulation
application (SolidWorks).
 Import the model into Ansys
 Analyse the meshed model in Ansys (Structural)
 Study planar mechanism kinematics (position,
velocity and acceleration) of the model using
SolidWorks

26.  Position analysis includes
the position of links at
different crank angle
 From this we can
determine the extreme
positions of the mechanism
Position Analysis

27.  Velocity Analysis
deals with variation
in velocity of
slider at different
instances
Velocity Analysis

28. Ground length = 25mm
 When crank radius
tends to ground length
, QRR tends to infinite
Crank radius = 10mm
 When ground length
tends to crank radius
length , QRR tends to
infinite
QRR Vs Crank Radius , QRR Vs Ground length

29. Fabrication
Fabrication is an industrial term refers to building metal
structures by cutting, machining and drilling.
The fabrication of quick return mechanism unit involves:
 Cutting
 Drilling
 Machining
 Welding
 Grinding
 Carpentry work

30. Fabrication of Crank and Connecting Rod
 The cutting operation can be carried out
in workshop
 For better accuracy , ease and surface
finish shaping machine is preferred
 Drilling of holes at ends of both sides
 The holes are drilled with respect to
suitable dimensions by using drilling
machine

31. Fabrication of Slider
 Wood is cut in suitable dimension
The carpentry operations are performed here
Fabrication of Frame
 A frame has to withstand the load of the crank as well
as the connecting rod to avoid disturbance
A wood plank may be chosen to avoid breakage and
also prevent noise
The frame is to be cut into required dimensions using
handsaw and chisel
The frame is to be tightened with the help of adhesives
and screws for rigid support
Grinding may be done for a smooth surface finish

32.  Machine tools
 Shaping machines
 Power-driven saws
 Slotter machines
Applications

33. Conclusion
The purpose of the project is to design and construct a
kinematic quick return device. Beginning with general
research into quick return devices, the project has to follow
a methodology of determining the design space, building a
mathematical model and then implementing that model. The
design process as a whole has to be experienced from start
to finish and is to be incorporated as a multitude of
different aspects of engineering. Designing this mechanism
will be an excellent experience in tackling a design project
where the majority of constraints are self-imposed. The
final design produced will be an effective one. Hopefully,
with a little work, the mechanism will be operational and
seen by future kinematics students for years to come.

34. ACTIVITY TIMELINE
Project Approval July
Consulting Guide & Background
Research
August
Proposing A New Design August
Design Specifications September
Software Learning October & November
Software Implementation And
Analysis
February
Presenting The Project March
PROJECT PLAN

35. Methodology
 Design of links
 Analysis of links at various positions
 Remodification of links (If required )
 Implementation
 Fabrication
 Performance test

36. BIBLIOGRAPHY
 Theory of Machines by R.S. Khurmi and J.K.Gupta
 Design of Machine Elements by R.S. Khurmi and J.K.Gupta
 Theory of Machines by Ratan
 Manufacturing Technology by P N Rao
http://www.morldtechgossips.com/2012/05/fabrication-of-
slider-crank-unit.html