BONGA UNIVERSITY

COLLEGE OF ENGINEERING AND TECHNOLOGY

DEPARTEMENT OF MECHANICAL ENGINEERING

COURSE TITLE: MACHINE DESIGN PROJECT I

GROUP ASSIGNMENT

NO NAME ID NO

1 SAMUEL GIRMA RU 2103/13

2 NEMOMSA REGGASA RU 2159/13

3 SANBATO LAMA RU 1775/13

4 MEGERSA TSEGAYE RU 2178/13

5 BURKA HAILU RU 2219/13

SUBMITTED TO INS: ERMIYAS T (Msc)

SUBMISSION TO: JAN, 2024

BONGA, ETHIOPIA
 ABSTRACT

The scissor jack, a mechanical device that provides vertical motion through the opening and
closing of a linked, crisscross pattern, has been a staple in the automotive and industrial
lifting equipment. This abstract aims to encapsulate the essence and significance of the scissor
jack in various applications, identifying its key components, historical development, and
fundamental principles of operation. The abstract will explore the mechanical function of the
scissor jack, elaborating on its ability to convert rotational motion into linear motion while
maintaining stability and load-bearing capability. Additionally, it will delve into the historical
origins and evolutionary advancements of the scissor jack, highlighting the innovations that
have shaped its modern-day iterations. Furthermore, the abstract will touch upon the practical
considerations and challenges associated with the scissor jack, including efficiency,
maintenance, and potential areas for improvement. By understanding its pivotal role in
facilitating vehicular maintenance, industrial operations, and beyond, this abstract aims to
underscore the enduring relevance and potential avenues for innovation within the realm of
scissor jack technology. In conclusion, the abstract will emphasize the ubiquitous nature of the
scissor jack, its impact on lifting and support applications and a fascinating design! It's a
marvel how such a simple mechanism can be so effective.

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 ACKNOWLEDGETMENT

First of all we would like to express our heartfelt thanks for our instructor INS: Ermiyas for his
consistent initiations and advices in doing this project work. Then, the role of our friend’s
involvement and support through this project also cannot be left unmentioned, since they have
gone through so many discouraging challenges with us. we would like to thank our family in
advising and encouraging us to attendee our education, and our university for its facilities such
as digital library, reference books, Wi-Fi and so on

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Table of Contents
ABSTRACT ................................................................................................................................................. ii

ACKNOWLEDGETMENT ........................................................................................................................ iii

CHAPTER ONE .......................................................................................................................................... 1

1 INTRODUCTION ................................................................................................................................ 1

1.1 Project Background ...................................................................................................................... 2

1.2 Problem Statement ....................................................................................................................... 2

1.3 Objectives ..................................................................................................................................... 4

1.3.1 General Objective ................................................................................................................. 4

1.3.2 Specific Objectives ............................................................................................................... 4

1.4 Scope ............................................................................................................................................ 5

1.5 Benefit of the Project .................................................................................................................... 5

1.6 Design Methodology .................................................................................................................... 7

CHAPTER TWO.......................................................................................................................................... 8

2 LITERATURE REVIEW ..................................................................................................................... 8

CHAPTER THREE .................................................................................................................................... 10

3 DETAIL DESIGN .............................................................................................................................. 10

3.1 Introduction ................................................................................................................................ 10

3.2 Main Components ...................................................................................................................... 10

3.3 General Design Considerations .................................................................................................. 11

3.4 Detail Design and Analysis Of Scissor Jack Component ........................................................... 12

3.4.1 Geometric Analysis ............................................................................................................ 12

3.4.2 Design of Lifting Member (Links) ..................................................................................... 14

CHAPTER FOUR ...................................................................................................................................... 25

4 WORKING PRINCIPLE AND MANUFACTURING PROCESS.................................................... 25

4.1 Working Principle ...................................................................................................................... 25

4.2 Manufacturing Process ............................................................................................................... 26

CHAPTER FIVE ........................................................................................................................................ 28

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5 CONCLUSION AND RECOMMENDATION ................................................................................. 28

5.1 Conclusion .................................................................................................................................. 28

5.2 Recommendation ........................................................................................................................ 29

REFERNCE ............................................................................................................................................... 30

6 APPENDIX ........................................................................................................................................ 31

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Table 1specification table ........................................................................................................................... 11

Table 2 Standard Dimensions Of Square Trade Bolt And Nut .................................................................. 31

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Figure 1 design of methodology ................................................................................................................... 7

Figure 2 at maximum lifting ....................................................................................................................... 13

Figure 3c-type member .............................................................................................................................. 16

Figure 4 threade rod force analysis ............................................................................................................ 17

Figure 5 design of nut of threade rod diamensions .................................................................................... 20

Figure 6 design of pin diamensions ............................................................................................................ 21

Figure 7 base plate dimensions .................................................................................................................. 22

Figure 8 driving handle dimensions ........................................................................................................... 24

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 CHAPTER ONE

1 INTRODUCTION

When it comes to lifting heavy loads, the scissor jack shines as one of the most essential
mechanical components. Its versatility makes it widely used in various applications, from cars
to lifts. However, the cost of traditional jacks can be a significant concern for many people.
This has led to a growing interest in alternative jacks that are not only more affordable but also
readily available and compact. Some popular alternatives include hydraulic jacks, pneumatic
jacks, and floor jacks. Among these alternatives, the scissor jack stands out as a favorite for
lifting vehicles. In fact, you might already be familiar with this type of jack, as it often comes
packaged with cars for emergency road-side repairs. One of its key advantages is its
lightweight nature, allowing for easy transportation and storage.

The beauty of a scissor jack lies in its simplicity. Its design consists of several components,
including a carrier plate, upper arms, lower arms, base plate, middle pins, and the all-important
power screw. This power screw is the heart of the scissor jack, enabling it to lift heavy loads
effortlessly. By utilizing the power screw and the interaction between the screw and the
middle pin, the scissor jack converts rotational motion into linear motion. This nifty
mechanism allows for efficient lifting of loads, making it a go-to choice for the average
consumer or vehicle owner. Scissor jacks are available in a wide range of options to suit
different load requirements. Whether you need to lift a lighter load or tackle something more
substantial, there's a scissor jack out there that's perfect for the job.

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 1.1 Project Background

The scissor jack, a marvel of engineering, exemplifies the ingenuity of human design. By
utilizing the principle of force magnification, this simple device allows us to effortlessly lift
heavy loads with minimal effort. In this project, our objective is to create an efficient scissor
jack capable of raising a 15 KN load. With a screw-driven mechanism, the jack will be
manually operated and provide a maximum clearance of 0.35 meters and at minimum height
of clearance 0.15 meters under load. To ensure practicality and versatility, our design will
prioritize portability and ease of storage. Additionally, we aim to optimize user experience by
incorporating a removable crank handle for convenience. Safety is of utmost importance,
hence our design will adhere to a factor of safety of n = 3, utilizing standard mechanical design
techniques for all components. Throughout the development process, our design has
undergone several iterations to address potential failure modes. By meticulously analyzing
various scenarios, we are confident that our final design is both efficient and reliable.

This project serves as an opportunity to explore new approaches to product design, presenting
innovative solutions that optimize cost, performance, and customer satisfaction. A key
objective of our project is to minimize unnecessary costs associated with the scissor jack.
Through careful consideration and evaluation, we aim to eliminate overdesign without
compromising on performance. By achieving cost reduction alongside enhanced strength and
durability, we anticipate an increase in market demand for our product. To further streamline
production, we are exploring alternative manufacturing processes for the scissor jack. By
transitioning from casting to steel metal, we can reduce material usage while maintaining the
required strength. This not only enhances the product's sustainability but also contributes to
cost reduction.

1.2 Problem Statement

In today's modern era, most cars in our country are equipped with various types of car jacks.
We have observed that many of these jacks pose a significant challenge, particularly for
women, as they require a substantial amount of strength and energy to operate. Recognizing
this issue, our aim is to develop a practical and cost-effective solution for car owners who
encounter difficulties when using a car jack. To address this problem, an extensive research

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study was conducted to explore innovative ways of designing a car jack that is not only user-
friendly but also energy-efficient. While there are numerous approaches to tackle this
challenge, our comprehensive analysis indicates that the proposed car jack system offers the
most practical solution in consideration of various factors and their respective consequences.

During our research, it became evident that many car owners struggle with vehicle
breakdowns, particularly when it comes to changing tires (ChetanS.Dhamak, 2020). The
existing car jacks available in the market are manually operated and highly time-consuming.
Moreover, they require a significant amount of physical effort to rotate the jack properly.
Hence, this report emphasizes the urgency to develop a car jack that is not only efficient but
also requires minimal effort. We firmly believe that this revolutionary redesign should be
easily accessible to all car owners, without burdening them financially. Our innovative car
jack design offers a remarkable user experience by incorporating cutting-edge technology
while ensuring simplicity and affordability. By eliminating the need for manual rotations, our
car jack significantly reduces the physical strain on users during operation. With just a press of
a button, the jack will effortlessly lift the car, enabling quick and hassle-free tire changes.

In addition to its ease of use and convenience, energy efficiency is a paramount consideration
for any modern product. Our redesigned car jack prioritizes energy-saving functionality,
further improving its environmental impact. Additionally, by utilizing readily available and
inexpensive materials, we have ensured that the manufacturing cost remains reasonable,
allowing for wider adoption of this groundbreaking solution.

Different Types of Jacks

Jacks are used for lifting heavy weights by applying a force on it. The different names for the
jacks are given depending upon the design, utility, technology used and customization etc. (Jim
Ramirez, David Hetinger, 2005)Some of the important jacks used for lifting are given below:
1. Scissor jack.
2. Hydraulic jack.
3. House jack/Screw jack.
4. Pallet jack.
6. Pneumatic jack.

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 1.3 Objectives

1.3.1 General Objective

In this project, we aim to design a simple yet efficient scissor jack and analyze its structural
improvements. Our goal is to create a modified jack that exhibits stability and can withstand
heavy loads, even on uneven surfaces or slight inclines. Additionally, we strive to enhance the
existing car jack's functionality while considering the human factor in its design. Ultimately,
we aim to develop a mechanical scissor car jack capable of adjusting the load of a vehicle
according to specific specifications.

1.3.2 Specific Objectives

To achieve these objectives, we will focus on the following key areas:

 Designing a stable and robust scissor jack

 Ensuring the jack can handle varying terrains and inclinations

 Implementing structural modifications to enhance stability

 Improving the functionality of the existing car jack

 Enhancing user experience and ease of use

 Incorporating human-centric considerations in the design process

 Developing a mechanical scissor car jack with adjustable load capacity

 Identifying the optimal load specifications for different vehicles

 Designing a mechanism to allow for easy adjustment of the load capacity

By addressing these objectives, we aim to revolutionize the efficiency and usability of car
jacks, providing users with a reliable and user-friendly tool for lifting vehicles. Our focus is on
creating a practical and efficient solution that meets the needs of both professionals and
everyday users alike. Stay tuned as we embark on this exciting journey of innovation and
improvement in the world of car jacks.
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 1.4 Scope

The scissor jack is a widely used lifting mechanism in automotive and industrial applications,
but it faces several challenges related to its mechanical design, efficiency, and usability. Let's
dive into the core issues: One of the top priorities of a scissor jack is to lift heavy loads safely
and efficiently, without any buckling or failure under stress. Maintaining stable lifting and
lowering action is crucial to avoid any mishaps. (C. Sai Kiran and J. Sruthi, December 2018)
The process of raising or lowering a vehicle or heavy machinery using a scissor jack can
sometimes was a time-consuming affair. Finding ways to enhance the lifting speed while
prioritizing safety is of great concern to the users. When it comes to the physical design of a
scissor jack, finding the right balance between height adjustment and compactness is key. This
is especially crucial as there are often space limitations under vehicles where the jack needs to
operate.

To ensure smooth and consistent operation over time, proper attention must be given to
lubrication and maintenance procedures. Excessive wear or insufficient lubrication can lead to
malfunctions, which we definitely want to avoid! Addressing these challenges in innovative
ways is necessary to improve the overall performance, reliability, and user experience of the
scissor jack in various lifting applications. Let's find some solutions that can make lifting tasks
more efficient, safer, and hassle-free.

1.5 Benefit of the Project

At the heart of every engineering product lies the need for cost-effective manufacturing. It's crucial to
create a versatile and aesthetically pleasing product that can withstand the test of time without any
failures. This is precisely why we embarked on a journey to design and analyze a jack model that could
handle the actual service loads of various models in the automobile light motor vehicle. sector. The
automobile industry is uncompromising when it comes to their requirements. (Ermiyas getent, solomon
girma, jan, 2019)With numerous jack options available in the market, such as screw jacks, we carefully
selected the traditional scissor jack for light motor vehicle. purposes. Our primary focus was to
eliminate permanent welds, as they posed a higher risk of failure. Instead, we opted for rivets, reducing
the chances of any welding-related issues. Additionally, we employed special manufacturing processes
and redesigned special brackets to minimize material usage.

Considering the current landscape of cost reduction, it is essential to find cost-effective solutions that
offer long-term benefits. By reducing the number of parts through an efficient assembly process and

5
avoiding welding joints, our jack model not only exhibits less deflection but also provides greater
accuracy.

Let's dive deeper into the benefits:

 Cost Reduction: One of the most significant advantages of our project is the automatic reduction
in material costs. By rethinking traditional manufacturing methods and incorporating innovative
techniques, we have managed to optimize the use of materials without compromising on quality.
This cost reduction ultimately translates into a more affordable product for consumers.

 Enhanced Performance: Our jack model's design and manufacturing improvements have
resulted in a product with superior performance. The use of rivets instead of weld joints not only
prevents failures but also reduces deflection, providing a more stable and accurate lifting
mechanism. This improved performance ensures a reliable and efficient experience when using the
jack.

 Longevity and Reliability: With the removal of permanent welds and the introduction of robust
rivets, our jack model boasts increased longevity and reliability. The elimination of potential weak
points reduces the risk of failures, ensuring that the jack can withstand the demanding service
loads of various automobile models in the long run. This means fewer repairs and replacements,
saving both time and money for users.

 Versatility and Adaptability: Our versatile jack model is designed to cater to the needs of
various automobile L.M.V. sectors. Its adaptability ensures that it can seamlessly handle different
service loads, making it an ideal choice for a wide range of vehicles. Whether you need to change
a tire on your car or provide maintenance for larger commercial vehicles, our jack model is up to
the task.

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 1.6 Design Methodology

Figure 1 design of methodology

7
 CHAPTER TWO

2 LITERATURE REVIEW

(ChetanS.Dhamak, 2020) optimize and standardize the current toggle jack to make the task
easier and reliable and to avoid field failure. They mainly focused on designing and
standardization of scissor jack model of automobile L.M.V. sector and trying for weight
reduction of scissor jack with good strength. They conclude that for safe design of screw and
nut a bearing pressure need to be considered and if we take combination of different material
for each pair of screw and nut so we can find best suitable material for design at maximum
load.

(Jim Ramirez, David Hetinger, 2005)The paper will include a scissor jack of automobile
L.M.V. vehicle and other same type of variants. This proposed design of scissor jack after its
stress analysis concludes that. This is a common jack for the variant (satisfying the product
requirements). The proposed jack has the reduced weight (by changing the manufacturability).
Designing this new jack reduces the no of parts for simplifying the assembly process.

(Ermiyas getent, solomon girma, jan, 2019)In this project generally we analysis the
mechanical scissor jack is feasible or applicable is safe with safety factor 2 to 3. In addition,
all most all parts of the mechanical scissor jack can easily have manufactured in the workshop
in such manners On calculating the designs of various components of scissors jack by taking
four different materials.

(C. Sai Kiran and J. Sruthi, December 2018)In this paper, a scissor jack is modeled in
SOLIDWORKS and a structural analysis of scissor jack with a force of 2943 N is performed
in ANSYS software. The total deformation and von-mises stress of the scissor jack is
analysed.From the results, it is observed that the maximum deformation and the von-mises
stress of the scissor jack are within the limits. Therefore, modelled scissor jack is safe to use
and has long life.

(R, jan, 2018)The paper will incorporate a scissor jack of automobile L.M.V. vehicle and other
same type of variations. This proposed plan of scissor jack after its stretch stress stretch push
investigation concludes that. Typically a common jack for the variant (satisfying the item

8
requirements).The proposed jack has the decreased weight (by changing the
manufacturability). Designing this modern jack decreases the no. of parts for rearranging the
get together process. Only bolt joints are actuated.

(Richard G. Budynas, 2011) We should to use that for c-type link elements of that’s
diamension such width, length or diametres and out of four materials AISI 1045gradedSteel is
also good for carrying maximum load but in comparison to mild steel it is more.GS -52.3 cast
steel is also falls under the safe limit so it can also be consider for manufacturing purpose of
scissors jack. In this Paper, we concluded that all four materials fallsunder the safe limit,
which is very important to avoid the failure.

(www.google.com) we can observe scissor jack elements, analyses of there elements, analysis
of force and bulk link and the selection of material and their property. another to that we can
search books about us title, journals , and research papers in our design of us project.

(www.google.com/youtube, 2017) we can seen some videos about design, assemble, working
condition and SOLIDWORK part drawing videoes.

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 CHAPTER THREE

3 DETAIL DESIGN

3.1 Introduction

In this chapter the material selection and the analysis of the force analysis. In this section we will be
selecting a material and computing/designing each part dimension from the given design specification.

3.2 Main Components

 LINK: The scissor jack consists of a set of linked arms, often in a diamond shape,
which extend and retract in a scissor-like motion. This scissor mechanism provides the vertical
lifting action when the jack is operated.

 THREADE ROD(SCREW): The lead screw is turned by a crank handle and contains
screw threads that convert the rotary motion of the handle into linear motion, causing the
lifting arms to extend or retract, in turn raising or lowering the jack's lifting platform.

 BASE PLATE: This is the sturdy bottom plate of the jack that provides stability and
support. It ensures that the jack remains steady and secure during the lifting process.

 UPPER PLATE: The upper part of the jack where the load is placed for lifting. It's
designed to evenly distribute the weight of the load during the lifting process. This is the part
that rises or lowers as the jack operates.

 CRANK HANDLE: The crank or handle is used to turn the lead screw. As the handle
is rotated, it causes the screw threads to extend or retract, initiating the vertical lifting or
lowering action of the scissor jack.

Each of these components plays a critical role in the operation of the scissor jack, collectively
enabling the vertical lifting or lowering of heavy objects, such as a vehicle during maintenance
or repair work.

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Design of mechanical scissor jack

Table 1specification table

PARAMETRES VALUE UNIT

Force or Weight 15000 N

Maximum Height of scissor 350 Mm

Minimum Height of scissor 150 Mm

3.3 General Design Considerations

 Type of load and stress caused by load

 Motion of parts or kinematics of the machine
 Selection of material –it is important that the designer should select appropriate and
most important material. By identifying characteristics of material like strength,
durability, flexibility, resistance to heat, machinability, welded or hardness.
 Convenient and economical features 
 Use of standard parts because of related to cost
 Safety operation
 Workshop facilities
 Cost of construction

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 3.4 Detail Design and Analysis Of Scissor Jack Component

3.4.1 Geometric Analysis

Scissor jacks are usually made of materials that are very strong and are suitable for
withstanding heavier loads on it.Evaluation and selection narrows down the range of
candidates to find the ‘best’ design for the purpose. There are so many steps are there in the
design process. Specifically we design the single mechanical scissor jack.
components such as it’s:
 upper link
 lower link
 base plate
 power screw
 fixed nut (screw housing)
 main nut(protective)
 driving handle

Scissor car jack where it’s maximum lifting capacity of 350mm and a minimum height of
150mm, to find a suitable length of links and the degree of angle of a maximum and minimum
height.

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 Hmax = 350mm

l = 30mm

y =20 mm

Figure 2 at maximum lifting

At the maximum height of the scissor jacks.

All links must be equal

∑
13
∑

:- Wherw F1 and FR was Force of link and Force on threaded rod respectively.

At the minimum height of the jack.

( ) ( )

3.4.2 Design of Lifting Member (Links)

These members are made from simple c-shape. The web of the lifting member is cut out near the pin
connections to allow proper serviceability of the scissor jack at its maximum and minimum heights.

Figure 3 Lifting member

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The life span of the jack will depend greatly on the type of materials used for each component to avoid
failure.

We select GS-52.3 cast steel material to design bolts because of:

 High level of ductility

 High strength

 Wear resistance

 Ease of producing component parts

 Economical.

For GS-52.3 cast steel:

From dimension and force analysis:

design stress the total result of yield strength over factory safety

15
 Figure 3c-type member

a = 7t

h = 5t

b = 3t

16
 Buckling of links

Effective length=l*c {c=1 therefore for pine to pine connection}

( )

TREADED ROAD

Figure 4 threade rod force analysis

axial force of trade rod

Material Selection For Traded Rod

 Cast Steel Gs-52.3

 High level of ductility
 High strength
 Wear resistance
 Ease of producing component parts

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 ⁄㎜

⁄㎜

Design stress ⁄㎜

㎜²

√ √ ㎜

 From Standard Table Of Screew dc=19mm

Ac=284mm²

MD=24.5mm

Dn=24mm

P=5mm

Depth of trade 2.75mm

 Checking for self Locking

Helix angle (ά)

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 Effort to raise the weight

Tuning moment to raise ㎜

Effort to minimize the height

Tuning moment for minimize the weight ( ) ( ) ㎜

√ √

do=37mm
G=28mm
N=8mm
dc=19mm without any consideration of clerance

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DESIGN OF NUT (THREAD ROD)

Figure 5 design of nut of threade rod diamensions

Material selection:-
 Cast iron
 Safe bearing pressure 12.6 – 17.6Mpa
 σy =276Mpa and
 σnt = 414Mpa

⁄( )

Shear Stress onthe Nut Threads Rod

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DESIGN OF PIN

Figure 6 design of pin diamensions

 steel a 1144 grade to design bolts

 stess ultimate = 565MPa = 565N/mm2
 yield stress = 310Mpa = 310N/mm2
 factory of safety = 3

 shear stress due to maximum applied force

then

d=18mm
w=36mm
diameter of heads is

therefore in this result of stess yield is greater than shear stress then

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DESIGN OF BASE PLATE

Figure 7 base plate dimensions

Material selection
 steel 1045 grade to design base plate






if and from standard table

width of link = (a)

width of the base plate (x)
=

UPPER PLATE
Material selection
 tensile stress = 1241Mpa
 yield stress 965Mpa
 young modulus E = 210Gpa
from standard table of C type material

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for calculating bulk link 29.1cm2

checking for bending stress

∑ -f =0

My=7500*x
at x=0; My=0
at x = 50mm
My = 7500*50 = 375 N.m
My = 7500 *25mm 187.5N.m
for maximum moment of Y axis 375 N.m

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DRIVING HANDLE

For ASTM A36 mildsteel

Mans power = 180N

Figure 8 driving handle dimensions

This implise the tuning moment for raise the weight is and the momet of
the handle by which means of mans power . So the equation and analysis
is correct and relable.

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 CHAPTER FOUR

4 WORKING PRINCIPLE AND MANUFACTURING

PROCESS

4.1 Working Principle

A scissor jack operates on a straightforward mechanical principle, where a mechanical

advantage is gained by the extension and retraction of a collapsible framework. Here's an
exploration of the working principles behind a scissor jack. The scissor jack consists of a
diamond shape assembly of linked metal struts, forming a geometric pattern that resembles the
shape of a pair of open scissors. The connected links combine to create a collapsible assembly
capable of vertical motion.

When the scissor jack is engaged, rotating a central screw or turning a handle, the linked struts
extend from their collapsed position, resulting in a vertical elevation of the jack's lifting
platform. This extension operation exploits the mechanical principle of transmitting force and
converting rotation into linear motion.

As the central screw or lifting mechanism turns, the parallel linkage of the scissor assembly
causes the struts to separate and extend. This extension process results in the lifting platform
ascending vertically, gradually elevating the load to the desired height through the application
of mechanical force.

The scissor jack's lifting platform supports the load, providing a stable surface for raising or
lowering the object. A locking mechanism, often integrated into the scissor jack's design, helps
maintain the lifted position securely, ensuring stability and safety during load handling.By
leveraging mechanical advantage through the scissor mechanism's geometric configuration,
the scissor jack enables the efficient application of force to lift heavy loads.

The interconnected struts further distribute the load, which enhances stability and minimizes
the risk of buckling or imbalance during elevation.Once the lifting operation is completed,
reversing the rotation of the central screw or handle causes the scissor assembly to retract,
collapsing back to its compact, stowed position. This retraction maneuver facilitates efficient
storage and ease of transport for the jack.
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While scissor jacks offer efficient and reliable vertical lifting, it's important to understand their
load-bearing limitations and to adhere to recommended safety precautions during operation.
Ensuring proper weight capacity, stable ground support, and secure load placement are critical
for safe and effective use of scissor jacks.

In summary, a scissor jack operates on the mechanical principles of force transmission, linear
motion, and mechanical advantage, enabled through the extension and retraction of an
interconnected scissor assembly. This fundamental mechanical process allows for efficient and
controlled vertical lifting of heavy objects, providing a practical and versatile solution for
various lifting application

4.2 Manufacturing Process

The manufacturing process of a mechanical scissor jack involves several key steps, from the
initial design and material selection to assembly and quality control. While the exact process
may vary based on the specific design and manufacturing facility, here's a general outline of
the manufacturing process for a mechanical scissor jack.

Design and Material Selection: The process begins with the design phase, where we can
create detailed specifications and drawings for the scissor jack. This includes determining load
capacities, dimensions, and functional requirements. (xin zhoa and zhung MA, Augest, 2016)
Material selection is also a critical part of the design, as it impacts the strength and durability
of the jack.

Material Preparation: Once the design is finalized, raw materials are sourced and prepared
for manufacturing. Common materials used for scissor jacks include steel and other high-
strength alloys. The materials are cut, shaped, and pre-processed to the required dimensions.

Machining and Fabrication: The components of the scissor jack, such as the base, link
members, and rod or screws, are manufactured through various machining processes. This
may include milling, drilling,boring, threading and welding to achieve the desired shapes and
features.

Surface Finishing:, surface finishing processes like grinding, polishing, and coating may be
applied to enhance the appearance and corrosion resistance of the jack parts.

Assembly: The machined and finished components are assembled to form the scissor jack.
This includes fitting the lead screw, attaching the lifting platform, and integrating the threaded
26
nut for the lifting mechanism. Other components, such as handles and safety mechanisms, are
also installed during assembly.

Quality Control and Testing: Once assembled, the scissor jack undergoes rigorous quality
control inspections and testing to ensure it meets safety and performance standards. This may
involve load testing, dimensional checks, and functional assessments to verify its lifting
capacity and operational reliability.

27
 CHAPTER FIVE

5 CONCLUSION AND RECOMMENDATION

5.1 Conclusion

The scissor jack is not only a reliable and efficient lifting tool, but it's also an affordable and
compact solution. Its easy operation and convenient storage make it a favorite among vehicle
owners and roadside repair enthusiasts alike. So, when you're in need of a reliable lifting
companion, look no further than the trusty scissor jack. Our project encompasses the
refinement of a crucial mechanical device, the scissor jack, through meticulous design and
engineering. By adhering to rigorous standards of safety, efficiency, and cost-effectiveness, we
aim to deliver a product that meets the needs of both industry professionals and consumers.
Through constant iteration and innovation, we endeavor to provide a new standard in scissor
jack design, bridging the gap between functionality and practicality. The development of a
user-friendly and cost-effective car jack is an essential step towards enhancing the overall
experience for car owners. By addressing the challenges faced by users during vehicle
breakdowns and tire changes, our redesigned car jack offers a practical and efficient solution
that is within reach for all car owners. Let us embrace this innovative approach,
revolutionizing the way we handle car maintenance and ensuring a smoother journey for all
drivers. Our project offers a host of benefits that address the specific requirements of the
automobile industry. Combining cost-effective manufacturing techniques with enhanced
performance, longevity, and versatility, our jack model stands as a testament to innovation and
reliability. Embracing these advancements will undoubtedly contribute to a more efficient and
seamless experience for both industry professionals and vehicle owners alike.

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 5.2 Recommendation

The scissor jack's weight capacity should exceed the weight of the vehicles it will be used to
lift. As a safety precaution, it's advisable to select a jack with a weight capacity that
comfortably exceeds the gross weight of the heaviest vehicle it will be used for. Look for a
scissor jack made of high-quality materials, such as steel or other strong alloys, with robust
construction. A durable and sturdy jack will provide safety and longevity. Ensure that the
scissor jack's lifting range is appropriate for the vehicles it will be used with. This is
particularly important for vehicles with higher ground clearance. Consider the weight and
portability of the scissor jack, especially if it will be used for roadside tire changes or
emergency repairs. A lightweight yet sturdy scissor jack can be more practical for such
scenarios. Look for a scissor jack with smooth and easy operation. This includes a user-
friendly crank or handle and a mechanism that functions reliably. Consider the extended height
of the jack and its stability under load. A stable base and extended height can facilitate easier
and safer lifting of the vehicle. Ensure that the scissor jack includes safety features such as
locking mechanisms, safety bars, or any other features that prevent it from collapsing when
loaded. Safety should always be a priority. Read user reviews and seek recommendations from
automotive professionals to gauge the overall quality and reliability of the scissor jack you are
considering. Look for jacks that comply with relevant safety and quality standards, as this
ensures that the product has been manufactured to a recognized standard of quality and
reliability. Consider the ease of maintenance and care of the scissor jack. A jack that is easy to
maintain will help ensure its long-term performance and longevity.

These recommendations can help guide you in selecting a scissor jack that best suits your
specific requirements and ensures safe and reliable lifting for automotive maintenance and
repair. It's important to research and consider different options before making a purchase to
ensure that the selected scissor jack meets your needs and safety standards.

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 REFERNCE

[1]C. Sai Kiran and J. Sruthi. (December 2018). Design And Stractural analysis Of Scissor Jack.
DEpartment of Mechanical Engineering. Haydembad ,India: CVR JOumal science and
Technology.

[2] ChetanS.Dhamak. (2020). Mechanical Scissor Jack. paper on design and optimization of
mechanical scissor jack, 54-61.

[3] Ermiyas getent, solomon girma. (jan, 2019). DESING PROJECT OF SCISSOR JACK. Gonder:
UNIVERSTIY OF GONDAR Dep OF Mechanical ENg.

[4] Jim Ramirez, David Hetinger. (2005). SCISSOR JACK DESIGN PROJECT. Roma, Itali.

[5] R, S. (jan, 2018). DESIGN AND ANALYSIS OF SCISSOR JACK. MATERIALS AND METHODS,
1571 - 1573.

[6](2011). Shigley’s. In J. K. Richard G. Budynas, Mechanical Design Ninth Edition (pp. 1010-1011).
NY, America: Raghothaman Srinivasan.

[7]Shubham Sukale1, Alimoddin Patel2, Digambar Date3 Vikramsinh Mane4. (june, 2019). Design
and Analysis of Scissor Jack for Light Motor Vehicle. osmanabad ,India: International Journal
Of Science And Technology Institute.

[8] www.google.com. (n.d.). scissor jack elements.

[9]www.google.com/youtube. (2017). enginering academy. assembly of mechanical scissor jack.

[10] xin zhoa and zhung MA. (Augest, 2016). Optimisation of Scissor jack Dampers parametres and
performance under the constrain of human comfort. shangai, china.

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 6 APPENDIX

Table 2 Standard Dimensions Of Square Trade Bolt And Nut

according to IS: 4694-1968 (Reaffirmed 1996)

31