1

PROJECT REPORT ON

A JACK CAR

Submitted in partial fulfillment of the

requirements for the award of the degree

of

BACHELOR OF TECHNOLOGY

in

MECHANICAL ENGINEERING

Submitted by

SAURAV BISWAS 2001413

SACHIN GOYAL 2001404

ROHIT SINGH KARKI 2001401

NISHANT MISHRA 2001368

Under the guidance of

Mr. GAGAN BANSAL

Assistant Prof. (ME Dept.)

DEPARTMENT OF MECHANICAL ENGINEERING

GRAPHIC ERA UNIVERSITY, DEHRADUN

MAY, 2013

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DEPARTMENT OF MECHANICAL ENGINEERING

CANDIDATES’ DECLARATION

I do hereby declare that the work which is being presented in this report entitled “A JACK

CAR” submitted towards the partial fulfillment of the requirements for the award of the

degree of Bachelor of Technology in MECHANICAL ENGINEERING from Graphic Era

University, Dehradun is an authentic record of my own work carried out under the

supervision of Mr. GAGAN BANSAL, Assistant Professor, Department of

MECHANICAL ENGINEERING.

Place: Dehradun Saurav Biswas

Date: Sachin Goyal

Rohit Singh Karki

Nishant Mishra

CERTIFICATE

This is to certify that the above statement made by the candidates is correct to the best of my

knowledge.

Date:

GAGAN BANSAL

Signature

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DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

This is to certify that the report entitled

A JACK CAR

Submitted By-

SAURAV BISWAS 2001413

SACHIN GOYAL 2001404

ROHIT SINGH KARKI 2001401

NISHANT MISHRA 2001368

may be accepted for the partial fulfilment for award of

Bachelor of Technology in MECHANICAL ENGINEERING.

Mr. ASHWINI KUMAR Mr. GAGAN BANSAL Mr. AMIR SHAIKH

Project Co-ordinator Project Guide Head of the

Department

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ACKNOWLEDGEMENT

Apart from our efforts, the success of any project depends largely on the encouragement and

guidelines of many others. We take this opportunity to express our gratitude to the people

who have been instrumental in the successful completion of this project.

We would like to show our greatest appreciation to Mr. GAGAN BANSAL, and Mr.

ASHWINI Assistant Professor, Department of Mechanical Engineering, Graphic Era

University, Dehradun. We can’t say thank you enough for his tremendous support and help.

Without his encouragement and guidance this project would not have materialized.

We express a deep sense of gratitude to Mr. AMIR SHAIKH, Head of the Department of

Mechanical Engineering, for providing an inspiration required for taking the project to its

completion.

We take this opportunity to thank our Honorable Chairman sir , Mr. KAMAL

GHANSHALA, for providing healthy environment in our college, which helped in

concentrating on the task.

We are also thankful to all the staff members, teaching and non-teaching for helping us

during this project. The guidance and support received from all the members who contributed

and who are contributing to this project, was vital for the success of the project. We are

grateful for their constant support and help.

SAURAV BISWAS

SACHIN GOYAL

ROHIT SINGH KARKI

NISHANT MISHRA

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CONTENTS

Title Page i. Candidates’ Declaration ii. Certificate iii. Acknowledgement iv. Contents v. List of Figures vi. List of Symbols vii. Abstract viii. CHAPTER 1: INTRODUCTION 1 1.1 Project Motivation 4 1.2 Back Ground 5 1.3 Problem Statement 7 1.4 Objective 8 1.5Scope 8 CHAPTER 2: LITERATURE REVIEW 9 2.2 Introduction 9 2.2 Terminology 9 2.3 Types of Car Jack 16 2.4 Screw Jack 18 2.5 Bevel Gear 27 2.6 Low Speed Geared DC Motor 27 2.7 Factors Determining The Choice Of Material 28 CHAPTER 3: CONSTRUCTION 31 3.1 Construction Phase 32 3.2 Lead Screw 33 3.3 Chassis 37 3.4 Specifications of Bevel Gear 38 3.5 Specifications of Dc Geared Motor 39 3.6 Switch 40 3.7 Cables 40 3.8 Battery 41 3.9 Prototype Model 42 CHAPTER 4:MERITS , DEMERITS & APPLICATIONS 44 4.1 Merits 44 4.2 Demerits 45 4.3 Applications 45 CHAPTER 5: FUTURE ASPECTS 46 CHAPTER 6: CONCLUSION 47 REFRENCES 48

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ABSTRACT

Now-A-Days, everybody is aware of the several complications and anomalies

that may or may not occur in a simple LMV. These complications include

unanticipated breakdown, flat tire, etc. or any such complication that renders the

vehicle to a halt and unusable. A crude solution for such complications that has

been implemented since a long time is a manually operated jack. Hence,

irrespective of its size and weight a jack that is used to lift the vehicle is one of

the most essential accessories that need to be constantly kept close at hand.

Thus, the need of keeping the jack available is undeniable. These days several

types of either manually operated or automatic jacks whether

lightweight/portable or heavy are widely used to fulfill their purposes in lifting

heavy as well as light equipments. There are only a few types of jacks that are

consistently used for lifting a vehicle during its repair work or any such purpose

viz. manually operated screw jacks, manually operated screw jacks, manually

operated hydraulic jacks etc. Even though they fulfill their purpose there is a

huge drawback to these kinds of jack i.e. they are manually operated and

consume a substantial amount of time and energy for their operation. Thus an

alternative for these jacks which is already integrated and automatic would

prove to be beneficial to the end user as well as the repairmen. One such

alternative is the Integrated Automated Screw Jack. This jack would be

permanently mounted on the chassis on the vehicle and will be automatically

operated which will evidently eliminate manually operating it to raise the

vehicle and would save valuable time.

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LIST OF FIGURES

FIGURE No. TITLE OF FIGURE PAGE No.

2.1 Screw jack 10

2.2 Pahl & Beitz Model of Design Process 14

2.3 A Car 15

2.4 House Jack 16

2.5 Graph b/w efficiency & Helix angle 21

2.6 Bevel Gear 27

2.7 Geared Motor 27

3.1 Prototype Mechanism 31

3.2 Lead Screw 33

3.3 Pitch Count 33

3.4 Major Diameter 34

3.5 Minor Diameter 35

3.6 Pitch Diameter 36

3.7 Types of Thread starts 36

3.8 Prototype Chassis 37

3.9 Bevel Gear Arrangement 38

3.10 Low Speed Geared DC Motor 39

3.11 Toggle Switch 40

3.12 Control Cables 40

3.13 12 V Car Battery 41

3.14 Lifted Front view of Prototype 42

3.15 Side View of Prototype 42

3.16 lift Provided by Prototype 43

3.17 Normal Stationary Position & Ground Clearance 43

.

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LIST OF SYMBOLS

η Efficiency

α Helix angle

ᵠ Angle of friction

μ Coefficient of friction

τ Torque

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CHAPTER 1

INTRODUCTION

1. INTRODUCTION:

Due to the difficulty of operating automobile jacks, various forms of electric

jacks have been proffered. With the development of such electric jacks has

gradually come an understanding of some of the problems associated therewith.

Due to the torque needed to lift something as heavy as most automobiles, direct

drive electric motors are not reliable; therefore, reduction gear drive

mechanisms of some sort should be employed, as a severe mechanical

advantage must be utilized. Direct motor-to-jack drive, with only two gears,

fails to accomplish this task. Electric jacks that are built into an automobile have

not been accepted due to expense and the need to at least lift each side of an

auto, if not all corners individually. If a system is chosen to individually lift

each corner of the auto, even greater expense in design, production, and cost is

encountered. Some have even entertained total encasement of a screw jack type

device. The invention relates to hydraulic jack and more specifically to an

automobile hydraulic jack system. In most of the garages the vehicles are lifted

by using screw jack. This needs high man power and skilled labors In the past

both hydraulic and pneumatic jack has been utilized in combination with the

structure of automobile. They have always utilized a separate jack for each of 4

wheels by having the jacks permanently installed on the vehicle. They are ready

to operation at all time. Lifting device has been installed on vehicle, such as air

lifting device. Various types of jack or lift devices has been installed on vehicle

which are turned in 1 fashion or another from a horizontal altitude into a vertical

altitude and then extended for the purpose of lifting the vehicle. It is an object of

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the invention to provide a novel screw jack system that only utilized screw

jacks, one that is mounted on chassis on side of car between two wheels and 2

jacks that is mounted on side of automobile between its side wheels. It is also an

object of invention to provide novel jack system that can be operated by driver

from inside the car. It is also an object of invention to. Now the project has

mainly concentrated on this difficulty, and hence such that the vehicles can be

lifted from the floor land without application of any impact force. By pressing

+the button in the dashboard, it activates the screw jack automatically.

It is believed that “Necessity is the mother of invention”. Here the necessity lies

in reducing the human effort applied during manual operation of the jacks and

hence the need of the invention. In day to day life it is very tedious job to

operate the jack manually and it is also a very time consuming work as well. To

reduce the human effort for operating any kind of jack separately. This will

most appropriately benefit senior citizens to provide a safe and simple

automatic screw jacking system without manual effort. To provide a novel

jacking system that can be operated from within the vehicle by means of a

dashboard control panel. There are certain mechanisms already available for the

same purpose which has a definite capacity to lift the car on 2 wheels viz. a

screw jack, hydraulic jack etc. But the general idea of the project is to minimize

the human effort while operating the jack. To provide a novel screw jacking

system that is directly and permanently incorporated into the vehicle frame in

such a way as to prevent the additional risk of damage or wear and tear.

A primary object of the present invention is to provide a motorized screw jack

for automobiles that can be used during inclement weather. Another object of

the present invention is to provide a motorized screw jack that is driven by the

electric power source from the 12 volt battery of any automobile. Yet another

object of the present invention is to provide a motorized screw jack that a motor

is provided for the rotation of a displacement screw, clockwise and counter

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clockwise in order to provide for the raising and lowering of the frame portion

of the screw jack. Still yet another object of the present invention is to provide a

motorized screw jack for automobiles that provides an upper limit switch

positioned in a sealed housing that as the jack moves in an upward direction a

driving element on one portion of the upper structure makes contact with a

biased displacement element on the opposing portion of the upper structure

driving a contact of the biased element into a contact of a fixed contact to

complete the limiting circuit. Another object of the present invention is to

provide a motorized screw jack for automobiles that provides a lower limit

switch that as the jack moves in a downward direction the displacement screw

comes in direct contact with a limit switch roller and drives a contact of a bias

displacement element into a fixed contact to complete the limiting circuit. An

object of the electric screw jack apparatus is to use electrical power already

available to elevate an automobile. Another object of the electric screw jack

apparatus is to incorporate a screw jack in electrically elevating an automobile.

An added object of the electric screw jack apparatus is to employ gear reduction

drive between the motor and the screw jack. A further object of the electric

screw jack apparatus is to ensure a fail-safe coupling between the gear reduction

drive and the screw jack. And, an object of the electric screw jack apparatus is

to gain electrical power from the battery from an automobile. Yet another object

of the electric screw jack apparatus is to provide for an inexpensive multiple

jack size utilization with a motor and gear reduction member change. A further

object of the electric screw jack apparatus is to be integrated.

Screw jack is one of the most widely used accessories for lifting vehicles and

light or heavy equipments. It is relatively cheaper than its counterparts and most

widely and readily available. It is made up of High Carbon Steel and other

alloying elements which impart strength and ductility. It is rigid in construction

but flexible in its pattern of usage. Flexible in a sense that it can used for a

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variety of purposes ranging from lifting of cars to elevating foundations of a

house for which screw jacks of very high capacity can be used.

1.1 PROJECT MOTIVATION

An automotive jack is a device used to raise all or part of a vehicle into the air

in order to facilitate repairs. Most people are familiar with the basic car jack

(manually operated) that is still included as standard equipment with most new

cars. These days, a car jack is an important tool to have in our vehicle due to

unknown upcoming event such as flat tire in our journey. Even so, people who

like to rotate their tires themselves or who may install snow tires before the

winter and remove them in the spring need to use a jack to perform the job.

Changing a flat tire is not a very pleasant experience.

Women may be able to drive a five-ton truck, but need a man's help if they must

change a tire. Women have a much lighter skeleton that means, among other

things, she can’t pull more forces as well as men and are at greater risk of

skeletal injuries.

Working near a vehicle that is supported by a car jack can be fatal. In Australia,

over the last four years at least 19 people have been crushed and killed by a

vehicle while they were working. All the deaths were men and involved the

vehicle being lifted or supported in the wrong way .On average, 160 injuries are

associated with car jacks each year. Injuries have ranged from amputation to

fractures and crush injuries. The correct use of jacks can prevent death or

injury.

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Available car jacks, however, are typically manually operated and therefore

require substantial laborious physical effort on the part of the user. Such jacks

present difficulties for the elderly and handicapped and are especially

disadvantageous under adverse weather conditions.

In today’s scenario basic problem arises with the families is of unloading the

luggage to get the car jack out of the car.

1.2 BACKGROUND

In the repair and maintenance of automobiles (car), it is often necessary to raise

an automobile to change a tire or access the underside of the automobile.

Accordingly, a variety of car jacks have been developed for lifting an

automobile from a ground surface. Available car jacks, however, are typically

manually operated and therefore require substantial laborious physical effort on

the part of the user. Such jacks present difficulties for the elderly and

handicapped and are especially disadvantageous under adverse weather

conditions.

Furthermore, available jacks are typically large, heavy and also difficult to

store,transport, carry or move into the proper position under an automobile. In

addition, to the difficulties in assembling and setting up jacks, such jacks are

generally not adapted to be readily disassembled and stored after automobile

repairs have been completed. Suppose car jacks must be easy to use for

pregnant women or whoever had problem with the tire in the middle of

nowhere.

In light of such inherent disadvantages, commercial automobile repair and

service stations are commonly equipped with large and hi-tech car lift, wherein

such lifts are raised and lowered via electrically-powered systems. However,

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due to their shear size and high costs of purchasing and maintaining electrically-

powered car lifts, such lifts are not available to the average car owner.

Engineering is about making things simpler or improving and effective. Such

electrical-powered portable jacks not only remove the arduous task of lifting an

automobile via manually-operated jacks, but further decrease the time needed to

repair the automobile. Such a feature can be especially advantageous when it is

necessary to repair an automobile on the side of a roadway or under other

hazardous conditions.

There also reports on car jacks which lead to a serious number of

accidents.These are due of safety features that are on conventional car jacks are

not enough. A specified jack purposed to hold up to 1000 kilograms, but tests

undertaken by Consumer Affairs has revealed that is fails to work after lifting

250 kilograms and may physically break when it has a weight close to its 1000

kilograms capacity. Whilst no injuries have been reported to date, Ms Rankine

has expressed concerned about the dangers associated with the use of a vehicle

jack that does not carry the weight it is promoted to hold. Tests have proven that

the jack has the propensity to buckle well under the weight it is promoted to

withstand, and it doesn’t meet the labeling or performance requirements of the

Australian Standard for vehicle jacks.

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1.3 PROBLEM STATEMENT

Available jacks present difficulties for the elderly, women and are especially

disadvantageous under adverse weather conditions. These presently available

jacks further require the operator to remain in prolonged bent or squatting

position to operate the jack.

Doing work in a bent or squatting position for a period of time is not ergonomic

to human body. It will give back problem in due of time. Moreover, the safety

features are also not enough for operator to operate the present jack. Present car

jack do not have a lock or extra beam to withstand the massive load of the car.

This is for the safety precaution in case if the screw break.

Furthermore, available jacks are typically large, heavy and also difficult to

store, transport, carry or move into the proper position under an automobile.

Suppose car jacks must be easy to use for pregnant women or whoever had

problem with the tire in the middle of nowhere.

The purpose of this project is to encounter these problems. An electric –

pneumatic car jack system Which would comprise of 4 electro-pneumatic jacks

attached with the chassis at the four corners each operating individually would

be developed. Operator only needs to press the button from the controller

without working in a bent or squatting position

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1.4 OBJECTIVES

In order to fulfill the needs of present car jack, some improvement must be

made base on the problems statement:

To design and implement a car jack system that is safe, reliable and able

to raise and lower the height level when framed with the chassis of a car

individually at each corners .

To develop a car jack system that is powered by internal car power and

fully automated working individually with a button system.

1.5 SCOPES

I. The developed automatic car jack can only withstand below

II. The developed automatic car jack must be operated on a flat surface.

III. The developed A jack car is only a prototype and not readily functioning

as commercial product.

IV. The design is based on current screw jack & cars in the market.

V. The developed A jack car is for all individual person.

VI. The developed A jack car can only work by using the internal car power

(12V)

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CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

The main purpose of this literature review is to get information about the project

from the reference books, magazines, journals, technical papers and web sites.

In this chapter the discussion will be made base on all the sources.

2.2 TERMINOLOGY

In this section, all the terminology on this project is presented.

2.2.1 Jack

A mechanical jack is a device which lifts heavy equipment. The most common

form is a car jack, floor jack or garage jack which lifts vehicles so that

maintenance can

be performed. Car jacks usually use mechanical advantage to allow a human to

lift a vehicle. More powerful jacks use hydraulic power to provide more lift

over greater distances. Mechanical jacks are usually rated for a maximum lifting

capacity (for example, 1.5 tons or 3 tons).

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Fig :2.1 Screw jack

2.2.2 Design

To design is either to formulate a plan for the satisfaction of a specified need or

to solve a problem. If the plan results in the creation of something having a

physical reality, then the product must be functional, safe, reliable, competitive,

usable,manufacturable, and marketable. .

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These terms are defined as follows:

I. Functional: The product must perform to fill its intended need and

customer expectation.

II. Safe: The product is not hazardous to the user, bystanders, or surrounding

property. Hazards that cannot be ‘designed out’ are eliminated by

guarding (a protective enclosure); if that is not possible, appropriate

directions or warning are provided.

III. Reliable: Reliability is the conditional probability, at a given confidence

level,that the product will perform its intended function satisfactorily or

without failure at a given age.

IV. Competitive: The product is a contender in its market.

V. Usable: The product is ‘user friendly’ accommodating to human size,

strength.Posture, reach, force, power and control.

VI. Manufacturable: The product has been reduced to a ‘minimum’ number

of parts.Suited to mass production, with dimensions, distortion, and

strength under control.

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VII. Marketable: The product can be bought, and service (repair) is available.

It is important that the designer begin by identifying exactly how to

recognize a satisfactory alternative, and how to distinguish between two

satisfactory alternatives in order to identify the better. From this,

optimization strategies can be formed or selected.

Then the following tasks unfold:

Invent alternative solution

Establish key performance metrics

Through analysis and test, simulate and predict the performance of each

alternative, retain satisfactory alternatives, and discard unsatisfactory

ones.

Choose the best satisfactory alternatives discovered as an approximation

to optimality.

Implement the design

The characterization of a design task as a design problem can introduce the idea

that, as a problem, it has solution. The design of the project is explained as

follows:

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Configuration:

Bevel gear arrangment,

bearing, housing

lead screw (the power screw)

Function: Elevating & Lowering

Power Source: Electrically

Characteristic:

Positioning precision,

Safely self-locking,

Heavy duty,

Uniform lifting speed,

small sizes,

easy installation,

low noise,

long life,

security and environment protection.

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2.2.2.1 Flow Chart of Design & optimization Process

Fig : 2.2 Pahl & Beitz Model of design Process

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2.2.3 CAR

An automobile, autocar, motor car or car is a wheeled motor vehicle used

for transporting passengers, which also carries its own engine or motor. Most

definitions of the term specify that automobiles are designed to run primarily on

roads. The term motorcar has also been used in the context of electrified rail

systems to denote a car which functions as a small locomotive but also provides

space for passengers and baggage. These locomotive cars were often used on

suburban routes by both interurban and intercity railroad systems. Most

automobiles in use today are propelled by an internal combustion engine, fueled

by deflagration of gasoline (also known as petrol) or diesel. Both fuels are

known to cause air pollution and are also blamed for contributing to climate

change and global warming.

FIG 2.3 A Car

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2.3 TYPES OF CAR JACK

2.3.1 House Jack Or Screw Jack

A house jack, also called a screw jack is a mechanical device primarily used

to lift buildings from their foundation for repairs or relocation. A series of jacks

are used and then wood cribbing temporarily supports the structure. This

process is repeated until the desired height is reached. The house jack can be

used for jacking carrying beams that have settled or for installing new structural

beams. On the top of the jack is a cast iron circular pad that the 4” × 4” post is

resting on. This pad moves independently of the house jack so that it does not

turn as the acme-threaded rod is turned up with a metal rod. This piece tilts very

slightly but not enough to render the post dangerously out of plumb.

Fig 2.4 House jack

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2.3.2 Hydraulic jack

Hydraulic jacks are typically used for shop work, rather than as an emergency

jack to be carried with the vehicle. Use of jacks not designed for a specific

vehicle requires more than the usual care in selecting ground conditions, the

jacking point on the vehicle, and to ensure stability when the jack is extended.

Hydraulic jacks are often used to lift elevators in low and medium rise

buildings.

A hydraulic jack uses a fluid, which is incompressible, that is forced into a

cylinder by a pump plunger. Oil is used since it is self lubricating and stable.

When the plunger pulls back, it draws oil out of the reservoir through a suction

check valve into the pump chamber. When the plunger moves forward, it pushes

the oil through a discharge check valve into the cylinder. The suction valve ball

is within the chamber and opens with each draw of the plunger. The discharge

valve ball is outside the chamber and opens when the oil is pushed into the

cylinder. At this point the suction ball within the chamber is forced shut and oil

pressure builds in the cylinder.

In a bottle jack the piston is vertical and directly supports a bearing pad that

contacts the object being lifted. With a single action piston the lift is somewhat

less than twice the collapsed height of the jack, making it suitable only for

vehicles with a relatively high clearance. For lifting structures such as houses

the hydraulic interconnection of multiple vertical jacks through valves enables

the even distribution of forces while enabling close control of the lift.

In a floor jack (aka 'trolley jack') a horizontal piston pushes on the short end of

a bellcrank, with the long arm providing the vertical motion to a lifting pad,

kept horizontal with a horizontal linkage. Floor jacks usually include castors

and wheels, allowing compensation for the arc taken by the lifting pad. This

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mechanism provide a low profile when collapsed, for easy maneuvering

underneath the vehicle, while allowing considerable extension.

2.3.3 Pneumatic Jack

A pneumatic jack is a hydraulic jack that is actuated by compressed air - for

example, air from a compressor - instead of human work. This eliminates the

need for the user to actuate the hydraulic mechanism, saving effort and

potentially increasing speed. Sometimes, such jacks are also able to be operated

by the normal hydraulic actuation method, thereby retaining functionality, even

if a source of compressed air is not available.

2.4 Screw Jack

Screw jack is a portable device consisting of a screw mechanism used to raise or

lower the load. There are two types of jacks most commonly used,

1] Hydraulic

2] Mechanical

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2.4.1 Merits of Screw jack –

1] Can be used to lift a heavy load against gravity.

2] Load can be kept in lifted position.

3] Due to leverage obtained by handle force required to raise load is very less &

can be applied manually also

2.4.2 Demerits of screw jack –

1] Chances of dropping of load

2] Tipping or slipping of load.

3] This failure is not “SAFE FAIL”& can cause serious accidents.

2.4.3 Reasons of Accidents –

1] Load is improperly secured on jack.

2] The screw jack is overloaded.

3] Center of gravity is off center with axis of jack.

4] Jack is not placed on hard & level surface.

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2.4.6 Efficiency of screw jack

The efficiency of square threaded screws may be defined as the ratio between

the ideal effort (i.e. the effort required to move the load, neglecting friction) to

the actual effort (i.e. the effort required to move the load taking friction into

account).

We know that the effort applied at the circumference of the screw to lift the

load is

P = W tan (α + φ) ...(i)

where W = Load to be lifted,

α = Helix angle,

φ = Angle of friction, and

μ = Coefficient of friction between the screw and nut = tan φ.

If there would have been no friction between the screw and the nut, then φ will

be equal to zero.

The value of effort P0 necessary to raise the load, will then be given by the

equation,

P0 = W tan α [Substituting φ = 0 in equation (i)]

This shows that the efficiency of a screw jack, is independent of the load

raised.In the above expression for efficiency, only the screw friction is

considered.

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Fig : 2.5 Graph b/w Efficiency & Helix Angle

2.4.5 Over Hauling and Self Locking Screws

We have seen that the effort required at the circumference of the screw to lower

the load is

P = W tan (φ – α)

and the torque required to lower the load,

In the above expression, if φ < α, then torque required to lower the load will be

negative. In other words, the load will start moving downward without the

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application of any torque. Such acondition is known as over hauling of screws.

If however, φ > α, the torque required to lower the load will be positive,

indicating that an effort is applied to lower the load. Such a screw is known as

self locking screw. In other words, a screw will be self locking if the friction

angle is greater than helix angle or coefficient of friction is greater than tangent

of helix angle i.e. μ or tan φ > tan α.

2.4.6 Efficiency of Self Locking Screws

We know that the efficiency of screw,

and for self locking screws, φ ≥ α or α ≤ φ.

∴ Efficiency for self locking screws,

From this expression we see that efficiency of self locking screws is less than ½

or 50%. If the efficiency is more than 50%, then the screw is said to be

overhauling.

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Note: It can be proved as follows:

Let W = Load to be lifted, and

h = Distance through which the load is lifted.

∴ Output = W.h

2.4.6 Screw jack has following parts :-

1] FRAME

2] SCREW

3] NUT

4] HANDLE

5] CUP

6] SET SCREW

7] WASHER

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2.4.6.1 FRAME –

• FRAME SIZE - Most of the times frame is conical in shape and hollow

internally to accommodate a nut & screw assembly. The hollow conical shape

insures a safe & complete resting of a jack on ground. If it is provided with legs

like structure , it quite possible that in case of uneven distribution load may fail

down because all legs will not touch ground.

• FORCE ANALYSIS – The force by a load is directed by a cup to screw then

is directed by cup to screw then to threads of screw to nut then to frame so it is

always compressive in nature.

• MANUFACTURING PROCESS – The complex shape of frame leads us to

use a ’Casting’ process for manufacturing. For all this purpose We need to

select a cast iron as material for frame. We select a FG200 as material for frame

such as it contains carbon precipitates as “graphite flakes” as graphite is soft in

nature it improves its ability to resist a compressive load.

FG200 = Graphite flakes Gray cast iron with ultimate tensile strength of

200N/mm2

2.4.6.2 SCREW –

• SCREW SIZE – Screws is nothing but a member having Helical groove

around periphery of solid bar. It can be around 22 to 100mm diameter for

square power screws & 24 to 100mm for trapezoidal power screws.

• THREAD PROFILE – The screw or power screw thread is always a square

type because it has more efficiency than trapezoidal threads and there is no

radial thrust on screw i.e. no Bursting Pressure, so motion is uniform.

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• Square threads usually turned on lathes using single point cutting tool. It

leads us to use free cutting steel.

• Square threads are weak in roots. Wear of thread surface lead us to use

“Unalloyed free cutting steel”.

We select “25C12S14 UNALLOYED FREE CUTTING STEEL”

It indicates - 025% carbon, 1.2% manganese, 0.14%sulphur

It has tensile strength of 560N/mm2 with 10% elongation. Sulphur gives

resistance to wear & 0.25% carbon gives it sufficient strength to compensate

weakness in roots. also easy in cutting due to manganese.

2.4.6.3 NUT –

• As we know there always a relative motion between screw and nut, which

cause a friction. The friction causes wear if some material is used for screw &

nut it will wears both components. So one out of two has to be softer than other

so as to ease of replacement. The size & shape of screw is costlier than nut, so

generally we use softer material for nut than screw.

• Phosphor bronze is ideal material for nut which is a copper alloy having

0.2%phospher which increases tensile strength. Ultimate tensile strength for this

is 190mpa and coefficient of friction is 0.1 Bearing pressure is 10mpa.

• Advantages of phosphor bronze are,

1] Good corrosion resistance.

2] Low coefficient of friction

3] Higher tensile strength than copper brass.

34

2.4.6.4 HANDLE –

• Handle is subjected to bending moments.

• So plain carbon steel with 0.3%carbon i.e. 30C8 can be selected.

• Yield strength in tension is 400mpa

2.4.6.5 CUP –

• Shape of cup is again complex and so economical to manufacture by Casting

process, hence material will be cast iron with grade FG200.

2.4.6.6 SETSCREW –

• Purpose of set screw is to resist motion of nut with screw. 5

• It can be of commercial steel.

2.4.6.7 WASHER –

• Washer is to provide uniform force of tightening nut over screw force by

enlarging area under actions of force. We can use commercial steel.

35

2.5 Bevel Gear

The bevel gears are used for transmitting power at a constant velocity ratio

between two shafts whose axes intersect at a certain angle.

Fig: 2.6 Bevel gear

2.6 DC Geared Motor

Fig 2.7 DC geared Motor

36

2.7 Materials

Materials require for the manufacturing of a components depends upon the

following factors:

FACTORS DETERMINING THE CHOICE OF MATERIALS

The various factors which determine the choice of material are discussed

below.

1. Properties:

The material selected must posses the necessary properties for the proposed

application. The various requirements to be satisfied can be weight, surface

finish, rigidity, ability to withstand environmental attack from chemicals,

service life, reliability etc.

The following four types of principle properties of materials decisively affect

their selection

a. Physical

b. Mechanical

c. From manufacturing point of view

d. Chemical

The various physical properties concerned are melting point, Thermal

Conductivity, Specific heat, coefficient of thermal expansion, specific gravity,

electrical Conductivity, Magnetic purposes etc.

The various Mechanical properties Concerned are strength in tensile,

compressive shear, bending, torsional and buckling load, fatigue resistance,

impact resistance, elastic limit, endurance limit, and modulus of elasticity,

hardness, wear resistance and sliding properties.

37

The various properties concerned from the manufacturing point of view are.

Castability,

Weldability,

Brazability,

orge ability,

erchantability,

urface properties,

hrinkage,

Deep drawing etc.

2. Manufacturing Case:

Sometimes the demand for lowest possible manufacturing cost or surface

qualities obtainable by the application of suitable coating substances may

demand the use of special materials.

3. Quality Required:

This generally affects the manufacturing process and ultimately the material.

For example, it would never be desirable to go for casting of a less number of

components which can be fabricated much more economically by welding or

hand forging the steel.

38

4. Availability of Material:

Some materials may be scarce or in short supply. It then becomes obligatory for

the designer to use some other material which though may not be a perfect

substitute for the material designed.

The delivery of materials and the delivery date of product should also be kept in

mind.

5. Space Consideration:

Sometimes high strength materials have to be selected because the forces

involved are high and the space limitations are there.

.

6. Cost:

As in any other problem, in selection of material the cost of material plays an

important part and should not be ignored.

Some times factors like scrap utilization, appearance, and non-maintenance of

the designed part are involved in the selection of proper materials.

39

CHAPTER 3

CONSTRUCTION

Worm and worm gear, bearing, housing and lead screw (the power screw).

Here in this project the lead screw is driven by the help of a worm gear

assembly which is automated by a help of a 12v dc low speed geared motor, as

we can see in the picture shown below:

Fig :3.1 Prototype mechanism

40

3.1 CONSTRUCTION PHASE

Now let us discuss the construction phase step by step:

First of all the jack with the above said dimensions is coupled with the

geared dc speed motor.

Now the motor is connected with a 12v dc supply keeping in mind the

power consumption of the motor the battery or the supply should be

capable enough to drive the motor.

Now this assembly is fixed with the help of nuts & bolts and welding

process as required with the frame of our vehicle. Here in our project we

have fixed the jack only in one place as we are trying to display the

concept so we have not placed the jack in all the four sides of the vehicle.

The frame is covered as required at the last, so that the display of the

concept is as same as in actual vehicle.

A 2-way switch has been used in order to drive the motorised jack.

The construction of our model has been kept as simple as possible

keeping in mind the abstract of the project and also keeping in mind the

cost limitation of the project so as to justify the prototype model concept

and to utilize the maximum resources available to us.

41

3.2 LEAD SCREW

The lead/ power screws (also known as translation screws) are used to convert

rotary motion into translatory motion In case of screw jack, a small force

applied in the horizontal plane is used to raise or lower a large load.

3.2.1Thread Form:

The lead screw having Acme threads having 29°thread angle.

Fig : 3.2 Lead Screw

3.2.2Thread Pitch:

The thread pitch is the axial distance from one thread groove to the next-

5.0mm

Fig :3.3 Pitch count

42

3.2.3 Major Diameter:

It is the largest diameter of an external or internal screw thread. The screw is

specified by this diameter. It is also known as outside or nominal diameter

The major diameter can be measured with a micrometer, caliper or steel rule.

Major diameters are generally the first numbers found in thread designations-

Major Diameter :20mm

2022

Fig : 3.4 Major Diameter

3.2.4 Minor Diameter:

It is the smallest diameter of an external or internal screw thread. It is also

known as core or root diameter.

The minor diameter can be measured with a micrometer, caliper or steel rule

Minor Diameter :17.2mm

43

Fig : 3.5 Minor Diameter

3.2.5 Pitch Diameter

It is the diameter of an imaginary cylinder, on a cylindrical screw thread,the

surface of which would pass through the thread at such points as to make equal

the width of the thread and the width of the spaces between the threads. It is

also called an effective diameter. In a nut and bolt assembly, it is the diameter at

which the ridges on the bolt are in complete touch with the ridges of the

corresponding nut.

Pitch Diameter:19.5mm

44

Fig : 3.6 Pitch Diameter

3.2.6 Hand of Thread:

The thread is of 1 start

Fig : 3.7 Types of thread starts

45

3.3 Chassis

The frame which supports an automobile is called Chassis.

The prototype of chassis is made up of cast iron hollow pipe material of

thickness 2mm and cross setion of 2 inch × 1 inch. The total length and width

of this rectangular frame is 3 feet × 2 feet.

The shape of the prototype chassis is close to the original chassis.

Fig 3.8 Prototype Chassis

46

3.4 Specifications of Bevel Gear

The bevel gear assembly shaped like right circular cone their imaginary vertices

must occupy the same point.

Fig : 3.9 Bevel Gear Arrangement

Pitch- 5.0mm

No of teeth Pinion 10

No. of teeth Gear 21

Major diameter of Pinion : 40 mm

Major diameter of gear : 90 mm

Minor Diameter of pinion :30 mm

Minor Diameter of gear : 80 mm

47

3.5 Specifications of DC Low Speed Geared Motor

Rated Voltage : 12V

Rared Speed : 50 RPM( max)

Rated Power :0 .15 hp

Rated Load : 60 watts

Rated Torque : 10 N-m

Mounting : M-6 screw holes

Shaft : 10mm shaft with 2 flats where flat is 6.6mm & threaded end to fit

a M-6 tightening nut.

-

Fig : 3.10 Low Speed Geared DC Motor

48

3.6 Switch

A switch is used in order to start or stop the entire operation of the screw jack.

The type of switch that is used is known as a toggle switch.

Fig : 3.11 Toggle Switch

3.7 Cables

Control cables are used in order to connect the battery to the motor and the

switch

Fig : 3.12 control cables

49

3.8 Battery

Lead–acid batteries, invented in 1859 by French physicist Gaston

Planté, are the oldest type of rechargeable battery. Despite having a

very low energy-to-weight ratio and a low energy-to-volume ratio, their

ability to supply high surge currents means that the cells maintain a

relatively large power-to-weight ratio. These features, along with their

low cost, make them attractive for use in motor vehicles to provide the

high current required by automobile starter motors.

Fig : 3.13 12 V Car Battery

50

3.9 Prototype Model

Fig 3.14 Lifted Front view of Prototype

Fig 3.15 Side view of prototype

51

Fig 3.16 lift Provided by Prototpe

Fig 3.17 Normal Stationary Position & ground Clearance

52

CHAPTER 4

MERITS, DEMERITS & APPLICATION

4.1 MERITS

Simpler Design: As all the components are pre-engineered only slight

modification is required

Almost zero maintenance

Cost of power transmission is minimum as it uses internal car power with

12V geared motor

Self locking Property of Power Screw reduces chances of accident.

Repairing is easy.

Replacement is easy

Manual Power not required.

If in case extra lift is required small manual screw loosening has to be

done.

The loaded light vehicles can be lifted easily

53

4.2 DEMERITS

The possible disadvantages of this invention may be as below, but if compare

with effective it is negligible.

Elements of this system have to manufactured separately to a high degree

of precision which increases the overall manufacturing cost of the system.

The entire system is subjected to mechanical friction, hence regular

lubrication must be provided

Intial cost in design modifications

Additional protection against rust and corrosion is required.

4.3 Applications

The innovation has several advantages and wide scope of applications:

It would be useful for car owners for onsite tyre replacement

It would be helpful for mechanics for reparing of parts on chassis

anywhere by lifting the car on integrated jacks.

It can be used in all types of LMV’s & with slight modifications on

SUV’s & LUV’s also.

54

CHAPTER 5

FUTURE ASPECTS

FUTURE ASPECTS:

This innovation would help the women elders and other fellow folks to

easily change the tires when stuck in the middle of nowhere.

This innovation would save time of installing a manual jack and

unloading the vehicle as the problem of unloading would be minimized.

It would help in washing of the lower body of the car as it would raise the

car by about 2 feet.

It would help the mechanic to repair on road as the innovation would

increase the road clearance of the car and would be easily repaired.

As the innovation is new and never been used anywhere in the world we

would work on this so we could PATENT our innovation.

Since a jack has always been an integral part of any operation related to

servicing of the vehicle therefore with some substantial modifications

like, by increasing the required torque and power capacity of the jack it

can be used also for HMVs. Some modifications can also be implemented

into the designing of the vehicle chassis to accommodate the jack. This

will not only be an efficient design but also be rugged.

55

CHAPTER 6

CONCLUSION

The present invention is a vehicle screw jack jack positioned on a each side

between the front and rear wheels with an electric dc geared motor drive

arrangement for the operation of lifting and descending of the vehicle to its

position for operation. The jack has gear configured for a low speed of

operation. Switches and are used to control the direction of movement of the

jack. Releasing the switches during operation stops the jack in the present

position. This invention relates to a jacking arrangement for automobiles

whereby a lifting jack is secured on the lower part of the chassis of a vehicle.

The jack has a screw jacks configuration with a a low speed geared motor motor

.The extension of the jack is limited by a switch handle which is configured for

cutting off the current flow as the switch is closed by the action of a power

screw approximately reaching a maximum extension position. Simultaneously,

a switch handle is depressed changing the polarity of the current flow through

the motor thereby positioning the motor for the retraction of the jack. At the

instant prior to the jack reaching a maximum retracted position, polarity switch

handle is depressed again reversing the polarity of the motor. In-place vehicle

jack assemblies of the pivoted lever type configured for being permanently

mounted at the front and rear of the vehicle frame structure are described. Each

of the jack assemblies comprises a unitary device which is independently

operable by an electrical motor, and independently selectively controlled at the

jack or remotely from the control compartment of the vehicle.

56

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Number 6,695,289 B1, 2004.

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“Motor driven scissor jack for automobiles,” U.S Patent Number

4653727, 1987.

3. John Norman (2009), Fire Department Special Operations.

4. Rodriguez, Daniel G. "Automatic Jacking System for an Automotive

Vehicle." U.S. Patent Number 6,991,221, 2006.

5. Integrated Automated Jacks for 4-wheelers P.S. Rana1, P.H. Belge1, N.A.

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8. William H. Crowse, “Automobile Engineering”.

9. Mechanisms In Modern Engineering Design Vol. V. Part I.

10. Elements Of Workshop Technology – VOL II -S. K. Hajra Choudhury.

11. R.S. Khurmi & J.K. Gupta ‘A Textbook Of Machine Design’-XIV Edition3