Final Project @1@1
Final Project @1@1
COLLEGE OF ENGINEERING
NAME ID NUMBER
JULY 29,2022G.C
ASSOSA/ETHIOPIA
Design and simulation of semi-automatic floor cleaning machine
DECLARATION
This is to certify the thesis prepared by Eyasu Abrham,Fasil Biset and Daniel Alemayehu,
entitled Design and simulation of semi-automatic floor cleaning machine and submitted
in partial fulfillment of the requirements for the Degree of Science in Mechanical
Engineering complies with the regulations of the University and meets the accepted
standards with respect to originality and quality.
Mr.
Graduate Committee
Mr.
Mr.
1. Mr.
ABSTRACT
In modern days, Humans are emphasizing the use of machines in day-to-day activities,
which reduce the time and effort required. With the advancement of technology
automating floor cleaning machines are getting more attention of researchers to make life
of human kind comfortable. Floor cleaning has always been most time-consuming and
tedious work as it is being done manually. The concept is developing in economic
countries but in the case of our country, these machines are not yet popular due to high
price of machines, complexities in design, operating cost and adaptation of new
technology. Due to these reasons, most of the Public services, households and industries
are still using traditional floor cleaning methods.
The cleaning purpose is specifically carried out by continuous relative motion between a
scrubber and the floor surface. During the cleaning and moving operation of vehicle
mechanism such as, driven wheels and guide wheels for the dry tracking on the floor
surface to be cleaned, suction of water is carried out by vacuum pump; the scrubber
directing water towards rear end does scrubbing action. This machine is capable of
performing cleaning of floor in dry as well as wet condition, and it have storage box to
store a dust and dirt.
SOLID WORK 2017 is used for 2D and 3D modeling to show the design parts and sub
assemblies. The assembly of the machine is done to visualize what the machine looks like
on SOLID WORK software.
Key word, Semi -Automatic floor cleaning machine, design and simulation
ACKNOWLEDGMENT
We would like to express our deep sense of gratitude and indebtedness to our supervisor
Mr. Ayenewu lecturer of Mechanical Engineering for providing precious guidance,
inspiring discussions and constant supervision throughout the course of this work. His
timely help, constructive criticism, and conscientious efforts made it possible to present
the work contained in this project.
We want also to express our sincere thanks to Assosa university and alumnus graduates
for their support and commitment. We are also thankful to all the staff members of the
department of Mechanical Engineering and to all my well-wishers for their inspiration
and help.
TABLE OF CONTENT
Contents Pages
DECLARATION ................................................................................................................. i
ABSTRACT ........................................................................................................................ii
ACKNOWLEDGMENT ....................................................................................................iii
LIST OF TABLE .............................................................................................................. vii
LIST OF FIGURE ............................................................................................................viii
NOMENCLATURE ...........................................................................................................ix
CHAPTER ONE ..................................................................................................................1
1. INTRODUCTION ...........................................................................................................1
1.1 Background of History Cleaning ............................................................................... 2
1.2 Problem Statement .....................................................................................................2
1.3 Objectives .................................................................................................................. 3
1.3.1 General Objective ............................................................................................... 3
1.3.2 Specific Objective ............................................................................................... 3
1.4 Scope ..........................................................................................................................3
1.5 Limitation .................................................................................................................. 4
1.6 Significance of the Project .........................................................................................4
CHAPTER TWO .................................................................................................................5
2. LITERATURE REVIEWS ..............................................................................................5
2.1 Types of Floor Cleaning Machine ............................................................................. 6
2.1.1 Hardwood Floor Cleaners and Steam Cleaners .................................................. 6
2.2.1 Vacuum cleaners ................................................................................................. 9
2.2.4 Portable Dryers ................................................................................................. 12
2.2.5 General Cleaning Equipment May Include .......................................................12
2.4 The Nature of Cleaning ........................................................................................... 15
2.5 Methods of Floor Cleaning ......................................................................................16
2.6 Types of Floor ..........................................................................................................17
2.6.1 Cement Concrete Flooring ................................................................................ 17
2.6.2 Timber Floors (Wood Flooring) ....................................................................... 18
LIST OF TABLE
Table 1 : Cleaning chemicals are classified in the following categories ...........................14
Table 2 : Nature of Cleaning ............................................................................................. 15
Table 3 : Decision matrix for cleaning dirt on floor ..........................................................31
Table 4 : Decision matrix Move the dirt to the tank ......................................................... 32
Table 5 : Some of selected material for semi-automatic floor cleaning machine ............. 34
Table 6 : Material and their stress (Gupta) ........................................................................35
Table 7 : Design value for journal bearing ........................................................................41
Table 8 : Horse power for V-belt (from Gupta text book) ................................................ 50
Table 9 : Density for different belt materials .................................................................... 53
Table 10 : The values of coefficient of friction for various materials of belt and pulley ..53
Table 11 : The mechanical properties of these grades of carbon steel ..............................62
Table 12 : Standard dimension of radial ball bearing ....................................................... 68
Table 13 : Materials and their stress (Gupta) .................................................................... 70
Table 14 : Design result of machine component ...............................................................74
Table 15 : Calculated cost of the machine design components .........................................81
LIST OF FIGURE
Figure 1 : Hard wood floor cleaning machine ....................................................................6
Figure 2 : Bluetooth based automatic floor cleaning machine ..........................................8
Figure 3 : Remote operated Robotic cleaning machine ...................................................... 8
Figure 4 : Vacuum cleaners ..............................................................................................10
Figure 5 : Manual scrubbing machines ............................................................................. 11
Figure 6 : Cleaning Equipment ........................................................................................ 13
Figure 7 : Floor cleaning accidents ................................................................................... 17
Figure 8 : Timber floors .................................................................................................... 18
Figure 9 : Brick floors ...................................................................................................... 19
Figure 10 : Plaster floors ................................................................................................... 20
Figure 11 : Ceramic Tile ................................................................................................... 20
Figure 12 : Methodological Procedure .............................................................................25
Figure 13 : Overall function structure ............................................................................... 30
Figure 14 : a) Concept 1 scrubber b) Concept 2 sweep ......................31
Figure 15 : Geometrical layout of semi-automatic floor cleaning machine ......................33
Figure 16 : Axle .................................................................................................................35
Figure 17 : Free body diagram of the axle ........................................................................ 36
Figure 18 : The wheel assembly ........................................................................................43
Figure 19 : The hub with all its dimensions ...................................................................... 44
Figure 20 : The hub with all its dimensions ...................................................................... 51
Figure 21 : pulley and belt geometry .................................................................................55
Figure 22 : Free body diagram for shaft. ...........................................................................64
Figure 23 : Section view of middle scrubbing .................................................................. 69
Figure 24 : Section view of corner scrubbing ................................................................... 69
Figure 25 : Assemble Drawing ..........................................................................................76
NOMENCLATURE
P = Power
N = Speed in RPM
As = shear area
Z = viscosity.
N = journal speed.
β = contact angle.
f = coefficient of friction.
M= bending moment
Z= section modulus
Tc =centrifugal tension
σc = crushing stress
CHAPTER ONE
1. Introduction
In large floor area such as malls, colleges, railway stations, hospital cleaning is serious
issue; it sets aside a lot of effort for the manual human hand or needs more labor. In
modern days, interior decorations are becoming important in our life and Cleanliness
plays a crucial role in adding value to ambience of any workplaces. However,
maintaining clean environment involves tedious work and high work force. Hence, there
is a requirement of designing and developing of floor cleaning machine.
Household cleaning is a repetitive task carried out by number of people every day. It is
also considering the intensity of labor required and improving qualities to its optimum
level. The need of designing a new technological based vacuum cleaner, which could
overcome the short coming of existing vacuum cleaner. Therefore, this semi-automatic
cleaning machine is very simple in construction and easy to operate. Anybody can
operate this machine easily. The size of the machine is also portable, so we can transfer
from one place to another place very easily. This machine is applicable for various floor-
cleaning activities. Hence, there is a need of bringing revolution in the area of science
and technologies, which could help easily in repetitive tasks, which we perform daily.
One of the most common techniques for cleaning carpet involved beating rugs with
brooms to remove sand, dust, and soot; however, this method did not remove stains.
Effective stain removal methods did not emerge until the 1830s, when creative
homemakers recorded their secrets for the removal of ink, grease, and oil. One stain
removal method involved scrubbing carpet with lemon juice and a hot loaf of bread.
During the late 1860s and 1870s, carpet-cleaning techniques took a leap for the better
with the advent of the first manually operated vacuum cleaner. The vacuum cleaner made
it easier for people to manage their daily housecleaning. Ives W. McGuffey invented the
Whirlwind, or the first manually operated vacuum cleaner in 1868. The Whirlwind‖ was
lightweight, compact, and difficult to operate [1].
Other inventors designed their own manually operated vacuum cleaners in the United
States and Europe. By the 1880s, readers could find an array of professional cleaning
advice in various publications. One carpet cleaning method involved mixing water and
bull’s gall before scrubbing it with a flannel cloth and then rinsing it with cold water. The
vacuum cleaning industry went silent during the 1920s and 1930s, because carpet had
become unfashionable during this time. However, most people acknowledged that rugs
needed vacuuming before shampooing. Over the years, the carpet cleaning and flooring
industry has improved its system and chemicals to clean more efficiently [8].
problems during cleaning which tends to increase manual effort. In addition, many types
of floor cleaning machines are available in the market that possess high range and high
cost. Therefore, keeping the focus on weight as well as cost, they are not affordable to
everyone. Also cleaning is done traditionally by sweeping the floor, and this sweeping
could result a major health issue. There is all kinds of dust and dirt flowing around in the
room, hence there is need to design and develop a floor-cleaning machine, which is a
combination of many mechanisms and cost effective. Design and development of floor
cleaning machine will reduce the cleaning time, increase the quality of cleaning and
reduce the fatigue of workers and at the same time will be cost efficient offering the same
specifications as compared to readily available machines in the market.
1.3 Objectives
1.3.1 General Objective
The general objective of this project is to design semi-Automatic floor-cleaning machine,
which can achieve dry and wet cleaning simultaneous in a single run.
1.4 Scope
The scope of this project is to design and developing semi-automatic machine that could
clean Cement concrete, floors and ceramic floors specifically, which are commonly used
in our country. For this project, proper cleaning is achieved by motion of the scrubber.
Motion is delivering from a dc motor. Special type of brush is mounted on the scrubber,
to wipe the dirt away.
The brush is called nylon bristle brush. There is a corner brush that is installed on the
machine, which helps for cleaning corners. Vacuum pumps are also used, this vacuum
pump sucks only wet-dirt’s from the floor. Thus, lead to proper cleaning of the surface.
There may be oily surfaces in some cases to counter act this situation necessary
disinfectants and liquid detergent are used and mixed inside the water tank before being
sprinkled & 3-wheel drive mechanism is used for proper control of the machine.
1.5 Limitation
The project is concerned in designing the semi-automatic floor-cleaning machine, which
has inability to perform the cleaning task without the power source (electrical current).
Besides the project machine is designed only to clean indoor areas like ceramic and
cement floors.
The design of the floor-cleaning machine is designed more specifically to clean flat
surfaces, which means bumped areas may not be get cleaned well using the machine.
CHAPTER TWO
2. Literature Reviews
Traditionally floor is cleaned by hand using different hand made instruments. Initially
different reed brushes washed it. According to Egyptian houses were built of sun dried
mud bricks at times white washed and the floors were stamped earth. The floor of the
outdoor kitchen too was simply the ground-baked stone hard by the sun. Unless it was
raining, which happened only rarely, these floors were easy to keep clean by sweeping.
Like most ancient Egyptian tools, these brushes did not have long handles, which would
have rendered their use less irksome, and required bending low when employing them.
For the ease of human being’s different designs of brushes are evolved. Again, during the
age of monarchs’ carpets of different designs are utilized to cover the floor to keep it
clean. As the time passed new scientific era begins many new methods are used to clean
the floor. The first among those was the reciprocating action of brush actuated by
muscular force. The brush design is changed time to time depending upon the floor
structure and ease of washing personnel. As the electricity came into role vacuum cleaner
are invented to clean a dry surface. Moving forward different floor cleaning machines are
being invented to clean the floor with less application of muscular power. Then, the
concept of mobile robot came.
Mobile robots have the capability to move around in their environment. In contrast,
industrial robots are usually more-or-less stationary, consisting of a jointed arm (multi-
linked manipulator) and gripper assembly (or end effectors), attached to a fixed surface
for the help of humankind the first-floor cleaner was manufactured during 1980s. In that,
equipment the aim was to wash the floor with less power utilization. They are sweeping
mechanism of mop is actuated by a timing motor which was controlled by the dc circuit.
Here water is sprinkled on the mop and hence the wet mop is used to clean the debris
from the floor. However, the problem here was it could not use any chemical solvent or
disinfectant. Again, for soaking purpose only hot air is used. Again, for moving the
machine a worker has to be engaged. To overcome these conflicts current study was done
to enable the cleaner move automatically throughout any kind of room. The moping
mechanism is also modified to lessen the cost. In current study, the mop is continuously
revolving about an axis perpendicular to the motion of the cleaner, which also helps in
directing water on the floor backward. Instead of using a wet mop, a sprinkle mechanism
is used to make the floor wet which the mop scrubs. A vacuum cleaner was used to soak
dirty water from the floor surface and side by side cleaning the surface. For automatic
motion of the cleaner mobile cleaning machines are used . [10]
Bluetooth module is used for controlling the entire system with help of remote or mobile.
There is an application in mobile for Bluetooth connection between the system and
mobile. By using Bluetooth module, we can direct and turn the system as the user needs.
It works great and controlled manually based on the user convenience.
Bluetooth Module
Bluetooth wireless technology is a 2.4GHz ISM-band open industry standard for short-
range wireless communication, which is capable of voice and data.
Voice appliances such as mobile telephones are also used for data applications such as
information access or browsing. Trough voice recognition, computers can be controlled
by voice, and through voice synthesis, computers can produce audio output in addition to
visual output. Bluetooth wireless communication makes provisions for both voice and
data, and thus it is an ideal technology for unifying these worlds by enabling all sorts of
devices to communicate using either or both of these content types Bluetooth is split into
two sections: Bluetooth Specification and Bluetooth Profile. The Specification describes
how the technology works The Profiles describe how the technology is used.
c) Technical Features
Bluetooth operates in the unlicensed 2.4 GHz Industrial Scientific Medical (ISM)
frequency band as shown in Figure below. It uses 79 channels between 2.402 GHz to
2.480 GHz. It uses power of 1mW to100mW. The nominal range is 10 meters, but can be
extended to more than 100 meters by increasing the transmission power to 100mW. The
gross data rate is 1Mbps. Bluetooth uses a combination of packet and circuit switching
technologies for transmission.
Cleaning equipment covers a wide range of products and items. The following
information is to help you decide which machine you may need to use. Electrical
equipment may cover.
The purpose of a vacuum cleaner is to collect all small pieces of litter and dust which is
embedded in the carpet. A vacuum cleaner is powered by a central motor, which drives a
fan creating suction.
The strength of suction is dependent on the power of the motor. They have a combination
of filters, which collect the dust and prevent it from being reticulated into the atmosphere.
The primary filter is the dust bag, which can be made either of fabric or of paper, which
is disposable.
Upright models
These are used by pushing backwards and forwards over the floor Older styles of upright
models have one motor which drives a belt which rotates the brush at the front. The brush
lifts the pile and the suction action, draws the dirt into the bag More modern models have
two motors, the main motor drives the fan and the second motor drives the brush which
rotates and sweeps the carpet as well as helping to lift the pile. The brush height can be
adjusted for different types of floor. The switch is usually located on the handle but can
also be foot operated.
Barrel style
The barrel vacuum cleaner is named because of its appearance. They are usually on
wheels with a flexible hose and have extension tubes with a nozzle attached. The nozzles
can be interchanged for different surfaces e.g., a brush nozzle would be used on hard
floor, where a flat nozzle would be used on carpet. The switch is located on top of the
barrel. The motor is attached to the base by clips and is removed when the vacuum
cleaner needs to be emptied. Most vacuum cleaners have a paper bag but many are also
used without the bag. When there is no paper bag, the secondary filter will block more
easily and this will cause the vacuum cleaner to age prematurely and becomes very messy
to empty.
Backpack
This is a vacuum cleaner where the body of the machine is carried on the back. It is worn
like a backpack and is strapped to the operator by straps and buckles. They are designed
to be used in areas where access is difficult e.g. in cinemas and theatres between all the
seats or in restaurants where there is a large amount of tables and chairs. They can be
heavy and hot if worn for an extended period. They are designed to be used on curtains
and air vents and periodically on carpets. The size of the machine limits the AMO of
suction that is generated. People who have bad backs should not use them.
The manual scrubbing machine requires the floor to be mopped first with wet
cleaning solution and then scrubbed with the machine using a bristle brush. The
wet solution can either be mopped away with clean water or suctioned with a wet
vacuum. Some models have a tank on the upright from which the cleaning
solution is dispensed by the operator.
The automatic scrubbing machine has simplified this method of cleaning as the
machine wets, scrubs and suctions in one pass. Inside the machine there are two
tanks:- the first has the cleaning solution and the second tank is empty. The
operator uses the switches and controls located on the handles and dispense the
cleaning solution. The brushes then scrub the floor as the machine moves forward.
At the back of the machine there is a squeegee attachment, which then passes over
the clean floor and suctions up the dirty cleaning solution in to the empty tank.
This makes large hard floor cleaning more efficient.
All machines are different but generally, they rotate between 150 and 650 rpm
(revolutions per minute) depending on what they are to be used for. These are classified
as slow machines many polishing machines are used in a side-to-side or "swing" motion.
The handle is lowered to move left and raised to move right some machines may have a
vacuum attached so they can polish and pick up dust at the same time. All machines
should have a protective skirting around. This helps to protect walls and furniture as well
as protecting them from chemical splash.
Blowers
Blowers are used outside to blow leaves and litter to a central point for pick up. Some
may also have a reverse action and can then vacuum up all the leaves and litter into a bag,
which is connected to the blower.
Buckets can be made of plastic or metals. There are single buckets and double bucket
systems. You may have a bucket purely to hold all your cleaning chemical bottles in or a
special long low bucket for window cleaning. Whichever type used, they must have a
strong handle and be heavy duty. Metal buckets may rust over time and leave marks on
the floors being cleaned. Castors may break, as may the mop wringer. Double bucket
systems are used for mopping and rinsing a floor. One bucket has the cleaning solution
and one has clean water for rinsing.
b) Mops
There are cotton mops, cotton/polyester blends, sponge mops, dust mops and microfiber
mops. Cotton and cotton polyester blends come in different weights. Female staff may
use a lighter one than a male. Cotton mops are used for mopping as they are more
absorbent and cotton/polyester ones are used for applying polishes to hard floor because
they are lint free and so do not leave particles. Microfiber mops do not require the use of
any chemicals. Sponge mops are not recommended for commercial heavy cleaning as
they disintegrate quickly.
C) Rakes
Rakes can be used for collecting leaves in outdoor areas but they are often used on carpet
to collect large amounts of litter (after parties when there may be streamers and balloons)
or after wet cleaning of long pile carpet to lift the pile. Specially designed carpet rakes
also exist.
Brooms are available in different widths and with different bristle types. Soft bristle
brooms are usually better on indoor hard floors and hard bristles better on outdoor areas.
The wider the broom, the larger the areas that can be swept in one pass.
Firstly, determine:
Detergents
Detergents used for cleaning are usually synthetic and are a byproduct of petroleum i.e.
they are manufactured in a laboratory and they are designed by chemists for specific
cleaning tasks They are usually slightly alkaline as they are designed to remove soil
which is acidic in nature Detergents are usually mixed with water at different dilution
rates in order to penetrate the soil and hold it in suspension until it can be rinsed away
Synthetic detergents have largely replaced the use of soap because unlike soap they have
a high tolerance to hard water and can be efficient at all temperatures. Soaps can leave a
scum film when used with hard water which can be redeposited on the surface that is
being cleaned Detergents can be formulated for floor cleaning Some may produce a high
foam (hand dish washing) and others a low foam (carpet cleaning detergents).
Method Tool
Air Movement Rubber bulb
Breath
Vacuum cleaner
Compressed air jet
Nylon bristle
Latex poultices
pencil eraser
accidental injury or death. Bad practice in floor cleaning is itself a major cause of
accidents
Durability:
Concrete floors possess good durability and resistance to abrasion and wear depending
upon the following factors:
on the floor surface that may result from absorption of oils is reduced by
increasing the density of floor finish.
Curing - Adequate curing is very essential to ensure good wear resistance.
Most brick floors were bedded directly on the earth or over a layer of sand or clay on a
bed of well-compacted rubble. Their surfaces are seldom level but this ‘defect’ will
usually contribute to the aesthetic value of a room. Many bricks are non-uniform
dimensions and of irregular thickness. It can be difficult to lift and reverse them and set
them to the level on a renewed base. If the joints between bricks have not been filled with
mortar, it is usually an advantage to leave them so. This will allow any moisture present
to evaporate through open joints instead of through bricks. Mechanical abrasive cleaning
methods can scar the surface and destroy the surface ‘skin’ coating making the bricks
more vulnerable to the absorption of dirt and erosion. Many old brick floors have worn to
a smooth hard surface and do not require further treatment. Here heavy silting on the
surface can be difficult to remove without saturating the bricks and introducing moisture
into the joints. Saturation can lead to efflorescence, which can also be difficult to remedy.
Surface dirt will usually respond to scrubbing with a bristle brush, using minimal
quantities of warm water and a little sulfate free detergent.
B) Plaster floors
Plaster was a sound, warm, economical and fireproof means of flooring and as a
lightweight material it was particularly suitable for finishing, mainly, upper floors.
Many such floors continued in use and were still being used A greater variety of
aggregates is usually visible in gypsum plaster floors compared with modern concrete,
especially after the surface has been wiped with a damp sponge .
Ceramic tile is one of the most durable floor and wall materials, that easy to care for it,
clean and available in hundreds of styles, wide variety of shapes, sizes and colors Is a tile
made of clay, by subjecting it to burn under high temperatures, then fat his face with a
layer strong quartz or basalt, the thickness of this layer thin, very often, so a value of
neglected relative to the thickness of the tiles.
Properties of ceramic
Temperature
Ceramic is cold when used as flooring and can be quite uncomfortable during wintertime
in colder climates. (Because of the density of ceramic, it takes longer to heat or cool than
other flooring materials).
Hardness
While most consider the hardness of ceramic to be an added value, there is also a
downside. Because the ceramic material has no flexibility, the ceramic itself is more
prone than other floor types to surface cracking when heavy items are dropped.
Durability
Ceramic tiles are very durable and lighter than porcelain or real stone tile flooring.
Properly installed, ceramic flooring will last for 20+years.
Suitability
Ceramic flooring is very easy to maintain. It is smooth and non-porous. Because of its
durability and its resistance to moisture
Technical characteristics
2.7.1 Soiling
Soiling may be considered as solid particulate matter sitting on the surface of an object.
Soiling includes dust accumulated over time on the floor. It also encompasses particulate
mineral and other matter that was previously suspended in liquid (often water but also
possibly oil or grease) and hardened by evaporation after having come into contact with
the object. Soiling may be bonded to a floor either mechanically or via electrostatic
attraction, hydrogen bonding or Van der Waal’s forces. This definition would also
describe the intentional application of a paint layer. i.e. a finely ground mineral pigment
suspended in water or a drying oil. Soiling on the other hand is normally considered as an
accidental process.
2.7.2 Staining
Staining occurs when liquid matters are carried in to a porous substrate by capillary
action, darkening or discoloring the surface. Again, staining is distinguished from
intentional dyeing by being an accidental event. Staining differs from soiling in that any
particulate matter must generally be very small in order to penetrate the pores of the
substrate. Staining an also be caused by liquids, either because the liquids are themselves
colored e.g. ink or coffee – or because the liquid changes color because of a chemical
reaction with the substrate or due to subsequent degradation of the liquid – e.g. oxidation
and yellowing of an oil or fat.
2.7.3 Corrosion
Corrosion is a general term that can describe alteration and degradation of the original
composition of the surface, either by external or internal chemical processes. Corrosion is
often used to describe the degradation of inorganic materials such as metal, glass or stone.
In the corrosion of metals water, oxygen or other corrosive gasses react with the surface,
which is transformed from a metallic state to a mineral, usually an oxide, carbonate or
sulphate Corrosion may take place above ground or within the soil for an archaeological
object and the thickness of the corrosion layer will depend upon the environment as well
as the type of metals involved. Corrosion usually involves the migration of charged ions
into and out of the metal surface. As a result, the outer layers of the object are
transformed into an oxide while the surface becomes covered with a mixed layer of
corrosion products depending upon the environment. Transformations are necessarily
accompanied by significant change in volume. Thus, the internal corrosion becomes more
porous but may also be distorted by blisters and pits. If the corrosion takes place in the
soil then the external corrosion incorporates soil, grit and any other material that is in
close proximity to the corroding metal.
CHAPTER THREE
3.1 Design Methodology and Materials
3.1.1 Design Methodology
In order to design semi-automatic floor cleaning machine we consider the following
procedures:
Selection of material (with justification)
Preparation to manufacturing component drawing and assembly drawing
Design material of machine components such as belt, shaft, axial, wheel
etc.
To clean the floor, fiber cloth is attached to the wiper, addition to that there is provision
of water jet through nozzle. Considering the ergonomics, position of handle is fixed, for
ease of operation two switches are provided. The machine steel is chosen for most of the
components since it having required properties. It is also beneficial from cost and
availability criteria.This machine is simply operated by pushing the handle with less
effort as heavy load rollers are provided at the base. Designed machine operates on
battery which can be charged either on solar or by electric supply. It is mainly designed
to clean the Educational institutes, malls, hostels, colleges, hotels so that hectic work of
sweepers can be reduced to great extent.
The overall methodology steps we possess to do this project are showed in the
schematic diagram below.
Ability to produce and provide required accuracy of shape and size and also
necessary surface finish.
Simplicity of design
Low Cost
Good Appearance
Durability
Strength
Corrosiveness
Availability
Quality
Cost
Durability:-The parts of machine are chosen that they may last for longer period before
any sign of damage may be noticed.
Strength:-Before any construction work could be done, the behavior of stress action on
the machine parts should depend on the load that machine is to carry and this is very
essential.
Corrosiveness:-Machine parts must be prevented from moisture as to prevent corrosion
of the machine. This is achieved by painting the machine parts.
Availability:-This is one of the most important factors to be considered when selecting
materials. The materials must be readily available at low cost to ease the construction
work and maintenance. The parameters considered in this automatic floor cleaning
machine design include the following: -
Weight of equipment for portability
Simplicity of design
pump with a debris chamber attached to it. The next aim is to make the surface wet which
is carried out by sprinkling water on the floor. The aim is achieved by using a motor and
a sprinkler system. This system has a shower like outlet and a chamber whose outlet is
controlled by a D.C motor pump. To clean the surface scrubber has to move or scrub over
the floor. The dirt should be completely removed and the debris laden water will flow
towards the rear of the bot. the scrubber is fixed to the chassis using clamps. The
construction of the scrubber includes fixing one side to the motor and the other to the ball
bearing. The bearing is clamped to the chassis. At the rear of the system a vacuum
mechanism is used to suck the debris laden dirty water. This is also the same type of
pump and the chamber.
Water tanker
Wheels
Shafts
Scrubber
Pulley
Vacuum cleaner
V belt
Motor and other links
CHAPTER FOUR
Product Specification
Based on the above machine requirements specification of the product was specified as
follows:
Angle of v groove (2β) in pulley is usually 300-40o degree for our design we selected 38o
Function Structure
To simplify the design process and to get plenty of alternative concepts, it important to
establish function structures.
Here are some initial factors to consider when determining whether sweeping, scrubbing
or a combination of both is best for your plant or warehouse.
Concept 1: attaching scrubber on rotating shaft while scrubber rotates the debris on the
surface of the floor move easily to next sub function.
Concept 2: attaching sweep on rotating shaft while the sweep rotates it moves the debris
on the surface of floor.
To choose the best design concept, decision matrix was made and concept 1 was selected
After lifting up the dirt from floor surface, the next task will be move the dirt to the tank.
To accomplish the task two design concepts were considered.
Concept 1 Concept 2
Weight
Criteria
Cost 1.5 9 10
Simplicity 1 8 8
Manufacturability 1 7 8
Safety 2 9 7
Space utilization 1.5 8 5
Dust blowing up 2 9 6
Power consumption 1 8 8
Sum 58 52
To choose the best design concept, decision matrix was made and concept 1 was selected.
Store dirt in dirt container: using medium size tank that a single person can unload the
tank easily.
During the embodiment design, the overall layout design, component shapes and
materials has been determined.
Material Selection
Material selected in order to ensure that the component functions well i. e. failures do not
occur too frequently. Further reasons are to make full use of the materials and to obtain
cost effective components. When we talk about selecting materials for a component, we
take into account many different factors.
During the selection process we considered different factors such as corrosion, weight,
strength, cost, availability and manufacturability of the components.
Material selections
Materials used for axle/shaft should have the following core properties:
It should have high strength: therefore, to with stand forces applied on it.
It should have good machinability: for the easy of manufacturing
Good heat treatment properties: This provides the shaft with good surface
properties that can resist failures due to fatigue, wear and creep.
It should have good wear resistance properties especially when there is a
necessity to use the axle with journal bearings and similar parts.
So, meet these requirements carbon steel is selected. It has carbon content 0.35-0.45%
and 0.6-0.9% manganese.
∑F x =0
R1 + R2 =294.3N
294.3
Therefore R1 = R2 = 2
=147.2N
��
Mmax = 4
147.2�×700��
= 4
= 25760N-mm
= 25.76 Nm
�y
σb = ��
=160Mpa is the allowable bending stress
����
σb = �
z=πd3 / 32
25.760
160MPa = πd3 / 32
25.760∗32
d= 160π∗106
=0.01179m= 11.79mm
We can take the diameter as much as we want as far as it is greater than 11.79mm to meet
other requirements.
The shear stress is applied at the wheel positions and it is due to the shear force of
147.2N.
��
�=
��
Where,
=147.2 *4/400π
= 0.468MPa
So the shear stress applied on the axle is less than the allowable stress, which implies
the axle is safe for shearing.
=5.88Nm
Formula P= 2πNT / 60
N= Speed in RPM
P=power
T=Torque
Design tip: for optimal continuous performance, DC motors typically operate at 70-90%
of its no load speed.
For design purpose the selected motor (550W) delivers 4.94N-M torque continually at
1410 RPM which is between 70-90% of its no-load speed.
550W motor torque = 4.94 N-M at 1410 RPM.
Then at 360 RPM Torque will be 14.6 N-M.
Hence, here 550W motor at 360 RPM can be used.
4.2.3 Bearing design
As we are looking for a component that are with by far manufacturability by local and
the raw materials are abundantly available with low cost, the first thing to be decided is
to see the properties of materials around us and select the suitable one. There are two
types of bearings commonly used for different machine components; sliding bearings
or rolling type bearings. Each of the above has its own merits and demerits with respect
to the other. Generally for low power operation requirements the sliding bearings have
the following advantages over the rolling one:
Rolling bearings may eventually fail from fatigue while sliding bearings are less
sensitive to fatigue
Sliding bearings requires less space in radial direction
Good damping ability
less noise level
less sensitive to sever alignments
low cost
highly available
However, in some cases where higher speed and power transmission required the rolling
bearings show the following advantages
Can support combined radial and axial load/thrust load
Less sensitive to interruption of lubrication
No self-excited instability
Good low temperature starting.
Can seal lubrication with in bearing and be life time lubricated
Looking closer to the working environment, the users’ economy and operating skill and
the above physical and mechanical comparisons, it is reasonable if the sliding bearings
are selected though it has some drawbacks that are not considerable limitations for
operation.
Hence the sliding bearings are selected the one used for the cleaner must possess;
Compression strength to resist permanent deformation
Suitability, ability to accommodate misalignments of journals
Low coefficient of friction and oiliness
Must be soft enough for the hard abrasive particles (dust, grit etc), that may interfere
its operation.
Resistance to corrosion so that it can with stand oxidation
Good heat conductivity to help the dissipation of heat generate3d
Low thermal expansion so that the clearance doesn’t change if bearing is to operate in
wide range of temperature.
Material selection
The common sliding bearing materials are:
Metals (Babbitt metal, Bronze, Cast iron, Silver etc.)
Non-metals (carbon graphite, rubber, wood, plastic)
The bearing for the cleaner wheel may be made from any one of the above recommended
materials. However, it is necessary to analysis the bearing especially for heat dissipation
capacity of the bearing by assuming particular material. Therefore, the bearing for the
wheel is designed considering cast iron journal type bearing.
Analysis
Assumptions
The design of journal bearing involves many variable; such as viscosity, Z; load per unit
projected area of bearing, p; the journal speed, N; bearing dimensions radius, r; clearance,
C; contact angle, ; length, l; and the performance variables: coefficient of friction, f;
bearing surface temperature, t ; heat generated and dissipated, Qg and Qd; the maximum
film thickness, ho.
Assuming radius of wheel 200 mm and the maximum good upper body strength
push horizontal force needed to move on the wheel maximum up to 50kg =490N,
where 1kg=9.81N.at the speed of 0.4m/s .The speed of the journal N will be
calculated as
� 0.4
�= == = 2rad/sec
� 0.2
When 1rad/s=9.5493rpm from this N will be calculated to be 19.1rpm
The maximum resultant assumed to be the resultant of the vertical weight and the
horizontal traction forces.
2
Load on the bearing F W F
2
R
W = (147.22 + 4902)0.5
=511.6N
Where: - F=R1 = R2 = 147.2N are reaction forces on the axle ends, which are
applied on the bearing, and d represents journal (axle) diameter.
�
Determine the bearing length by choosing �
ratio of 2
The minimum value of the bearing modulus k at which the oil film will break is given
by:
��
3K= �
= 7=K=2.33..................................................................................... (4.2)
Since the calculated value of the bearing characteristics number is greater than the
maximum requirement K= 2.33, therefore the bearing will operate under hydrodynamic
conditions.
Where k= factor to correct leakage. It depends on the ratio of l/d, k=0.002 for l/d ratios
of 0.75 to 2.8
� = 0.011
Heat generated �� = µ��
� �
�� = �. �. � �. � �� � �� �����…(�) �ℎ��� � =
����������� �� ��������, � = ���� �� �ℎ� ������� �� �,
= �������� �� �ℎ� ������� �� �/��2
× ��������� ���� �� �ℎ� ������� �� ��2 = � (� × �),
� = ������� �������� �� �/� = ���/60
, � �� �� ������, ���
���
� = ����� �� �ℎ� ������� �� �. �. �. Where � = 60 ........................ (4.4)
�� = 0.12����
Heat dissipated Qd=C.A(tb-ta)=C.l.d(tb-ta), A=ld............................................(4.5)
Where C=heat dissipation coefficient. For unventilated air C is in the
range of 140-420 w/m2/oC. Take C=180 w/m2/oC
�� = 0.72����
It has been seen that the heat generated is smaller than the heat dissipated which implies
that the bearing is safe, that is it doesn’t need artificial cooling.
C
Recommended value of C for bearings is 0.001
d
Where d is diameter of axle, d= 20mm, => db= (20 + 0.03) mm
Bearing outer diameter do= 40mm
The wheel hub is the one which have direct contact with the axle. It is fixed with the axle
using nail through hole provided both in the hub and the axle.
Since we have chosen carbon steel for the axle, we should choose a comparable material
for the hub too. This is to reduce wear of parts due to hardness difference. Therefore, we
choose the same material for the axle.
��
Shear stress = ��
= 160MPa
160=147.2/As
As=147.2/160=0.92mm
And we have A s = L * t
We have
570
σc allow = σt = 2
= 285mpa Where 570= ultimate tensile strength of carbon steel
Fc
σc = Ac Where Fc=Fr=147.2N reaction force at the support of the axle
πdl
Ac = 2
π×200×20
Ac = 2
= 6280mm2
147.2N
σc = 6280mm2 = 0.02mpa
The value is very less than the allowable shear stress. So, it is safe for crushing.
��
�� =
��
Ft= 147.2���
�� = 2�� = 12560��2
147.2
Therefore �� = 12560 = 0.01���
The allowable tearing stress is less than allowable bearing stress of the material. So, the
hub is safe for tearing.
Generally, the hub with such a material is safe enough. Strength is not critical here.
But to meet other requirements we may change the hub thickness and length as
required. As checked in the previous analysis
2. Design of Arms
1. Compressive stress when arms are in the lower half of the wheel
2. Tensile stress when arms are in the upper part of the wheel
3. Bending stress due to the tangential force developed at the circumference of the
wheel.
In the preceding analysis the wheel diameter has been assumed to be 200mm. So,
subtracting the outer hub diameter from the wheel diameter, the length of the arm will
be 200mm – (40+ (2*t)) mm = 160mm.The total number of arms recommended for a
wheel with a diameter of 200mm is 12.
Material for the wheel should full fill certain property requirements that are necessary to
with stand the above three critical stress and be able to easily couple to the hub of the
wheel. Therefore the material selected for the arm of the wheel is carbon steel used so far.
For a cantilever beam the bending moment and stress relation is:
�
�� = � ………………………………………………….(4.6)
��
Where �� = �� = �� = 160��� i.e yield stress=320 and safety factor =2
294.3
M= bending moment M= �� × � =11760 N-mm where �� = 4
= 73.5N
�
�� = �
� .ra3 .ra3
=Z , i.e. for half of the arms Z 6
�� 32 32 ……………………….. (4.7)
ra = 5 mm => da =10 mm
3. Designs of the Rims
The rim of the wheel critically subjected to three main stresses: tearing, shearing,
bending stress at the rim part between consecutive arms ends.
Assumptions
For shearing it is assumed only parts of the rim with area equals to the projection of the
end of the arm end is subject.
In case of tearing it is assumed that only the part between two arms is assumed to be
subject to. The bending is critical when the part of the rim at the middle of two
consecutive arms is in contact to the ground.
From the angle of application of the force Fb the horizontal component of this force is
not significant as compared to the vertical component. Assuming only the two arms are
subjected to the load, Wt =294.3N
Fby = Wt / 4 = 73.5N
And considering the rim portion as a cantilever fixed at the middle ‘o’
�
�� =
�
��� �
�� =
�
��2
And � = �
So, rim cross section.
A belt provides a convenient means of transferring power from one shaft to another.
Belts are frequently necessary to reduce the higher rotational speeds of electric motors
to lower values required by mechanical equipment (Spotts 1985). The belt driver relies
on frictional effects for its efficient operation. When the belt connecting two pulleys is
stationary the tensions in the two portions of the belt are equal but when torque is
applied to the driving pulley, one portion of the belt is stretched and the other portion
becomes slack.
Following are the various important factors upon which the selection of a belt drive
depends:
Speed of the driving and driven shafts
Power to be transmitted
Position of shaft
Service conditions.
Types of belt drives
Depending on speed the belt drives are usually classified into the following three groups:
1. Light drives: These are used to transmit small powers at belt speeds up to about 10
m/s as in agricultural machines and small machine tools.
2. Medium drives: These are used to transmit medium powers at belt speeds over10
m/s but up to 22 m/s, as in machine tools.
3. Heavy drives: These are used to transmit large powers at belt speeds above 22 m/s
as in compressors, crushers and generators.
Based on shape belts can be classified as:
A. Flat belt. The flat belt is mostly used where a moderate amount of power is to be
transmitted, from one pulley to another when the two pulleys are not more than 8
meters apart.
B. V-belt. The V-belt is mostly used where a great amount of power is to be
transmitted, from one pulley to another, when the two pulleys are very near to
each other.
C. Circular belt or rope. The circular belt or rope is mostly used where a great
amount of power is to be transmitted, from one pulley to another, when the two
pulleys are more than 8 meters apart.
Since huge amount of power transmitted by floor cleaning machine V-belt type
has been selected.
The procedure for selecting a V-belt drive is dependent on the motor horse power and the
speed (rpm) rating. V-belts are rated from class A to E.
A Up to 0.7 75 13 8 1.06
B 2-15 125 17 11 1.89
C 7.5-75 200 22 14 3.43
D 20-150 355 32 19 5.96
E 30-350 500 38 23 -
Table 4.6 Dimensions of standard V-grooved pulleys according to IS: 2494–1974. (All
dimensions in mm).
(r1+r2)2
We know that the pitch length of the belt, L = π(r1 + r2) + 2x+ x
The amount of power transmitted by belt depends upon the following factors:
The arc of contact between the belt and the smaller pulley.
2. Since the V-belts are made endless and there is no joint trouble, therefore
the drive is smooth.
2. Cotton or fabric belts. Most of the fabric belts are made by folding Convass or
cotton duck to three or more layers (depending upon the thickness desired) and
stitching together. They are impregnated with some filler like linseed oil in order
to make the belt water-proof and to prevent injury to the fibers. The cotton belts
are cheaper and suitable in warm climates, in damp atmospheres and in exposed
positions.
3. Rubber belt. The rubber belts are made of layers of fabric impregnated with
rubber composition and have a thin layer of rubber on the faces. These belts are
very flexible but are quickly destroyed if allowed to come into contact with heat,
oil or grease. One of the principle advantages of these belts is that they may be
easily made endless.
4. Balata belts. These belts are similar to rubber belts except that balata gum is used
in place of rubber. These belts are acid proof and water proof and it is not affected
by animal oils or alkalis. The balata belts should not be at temperatures above
40°C because at this temperature the balata begins to soften and becomes sticky.
The strength of balata belts is 25 per cent higher than rubber belts.
The ultimate strength of balata belt varies from 21 to 35 MPa and a factor of safety may
be taken as 8 to 10. However, the wear life of a belt is more important than actual
strength. It has been shown by experience that under average conditions an allowable
stress of 2.8 MPa or less will give a reasonable belt life. An allowable stress of 1.75 MPa
may be expected to give a belt life of about 15 years.
Canvass 1220
Rubber 1140
Balata 1100
Coefficient of friction between belt and pulley
The coefficient of friction between the belt and the pulley depends upon the following
factors:
The material of belt
tanned
Cotton 0.22 0.15 0.12 0.25 0.28 0.27 0.3
woven
Rubber 0.3 0.18 - 0.32 0.35 0.4 0.42
From the above table 4.8 balata v-belt type with cast iron pulley material of dry type
which has coefficient of friction (=0.35) has been selected.
Center distance (adjustment for center distance must be provided or use idler
pulley) nominal range D2 < C < 3(D2 + D1)
Power rating for one belt as a function of size and speed of the smaller sheave
Number of belts
The included angle (2β) for the V-belt is usually from 30° to 40°. For our design
we have been taken (2β)= 38
�2�2
�1 = , D1=36mm
�1
140−36
= 2� 200 = 0.26���
� = 15.1°
Where:
α- is angle of lap
β - is angle of contact
�1 = 180° − 2� = 149.8°
�1 = 2.6 ���
�2 = 180° + 2� = 210.2°
�2 = 3.66 ���
When pulleys have different angles of contact (�) then the design will refer to a pulley
for which the value of (� × �) is small.
Since (�. �) for smaller pulley is small, therefore the design is based on smaller pulley.
���1
Belt speed (V)= 60
= 4.26�/�
=200*10−6 �2 × m×1100kg/�3
=0.22kg/m
Since the belt continuously run over the pulley, therefore some centrifugal force is caused
whose effect is to increase the tension on both the tight and slack sides.
r = Radius of pulley over which the belt runs in meters, and TC = Centrifugal tension
acting tangentially at P and Q in newton’s.
Maximum (total) tension in belt- it is equals to the total tensions in tight side of the belt.
T= T1+�� or
= 800N- 4N=796N
When centrifugal tension is neglected than T=T1, i.e. tension in the tight side of the belt.
We know that ratio of driving tension for the belt drive give the following relation
between the tight side and slack side tensions, in terms of coefficient of friction angle of
contact.
�1
2.3log �2
=� × �1������ = 2.4
�1
log �2
=2.4/2.3=1.04
�1
�2
=antilog (1.04) =11.02
T2=72.5N
=3082.11W=3.082KW
0,55��
n =3.8845�� = 0.14 ≈ 1
� �1+�2 �2+�1 2
L= 2
+ 2� +
4�
� 36+140 140+36 2
L= 2
+ 2 × 200 + 4�200
L=716mm
4.2.6 Pulleys
Pulleys used for the v-belt drive mechanism, as specified previously first of all should
have to satisfy the geometric requirements. Then to take care of strength, reliability and
durability necessities the selection of material for the pulley should be based on such
considerations in addition to cost, availability and manufacturability requirements.
Pulley materials
Commonly used pulley materials are metals which include cast iron, steel, aluminum etc.,
and to light duties non-metallic pulleys are used such as plastic, paper and wood are the
commonest of the non-metallic pulleys. Metallic pulleys are most of the times used for
high power rating and greater load capacity transmissions. They are most reliable and
durable pulleys against variable working environment.
Nonmetallic pulleys made of wood or plastic on the other side are used for less power
rating and minimum load operations. They are naturally susceptible to difficult failures;
however, with proper care and provision they are giving service for acceptable life with
accurate transmission. The cleaner belt system is required to transmit very low power and
load but with high accuracy and efficiency, therefore, the wooden pulley can be used
properly with great advantages and can perform as good as enough to achieve by the
rotation.
Cast iron is selected as a material for both small and large pulleys. Pulley material must
have the following properties
Dimensions of pulley
i. The diameter of the pulley (D) may be obtained either from velocity ratio consideration
or centrifugal stress consideration. We know that the centrifugal stress induced in the rim
of the pulley, σt = ρ.ν2 where ρ = Density of the rim material = 7200 kg/m3 for cast iron
ν = Velocity of the rim = πDN / 60, D being the diameter of pulley and N is speed of the
pulley.
�1 �2
Speed ratio= �2 = �1
�2�2
�1 = �1
, D1=36mm
ii. If the width of the belt is known, then width of the pulley or face of the pulley (B) is
taken 25% greater than the width of belt. ∴ B = 1.25 b ; where b = Width of belt.
For a 5 mm thickness v-belt , the width is taken as between 35 to 65 mm. we took a 5mm
thickness and a 40 mm belt width for the design.
B = 1.25 *b =1.25*40=50mm. i.e. 50mm width pulley is used for our design.
A shaft is a rotating member, usually of circular cross section, used to transmit power or
motion. It provides the axis of rotation, or oscillation, of elements such as gears, pulleys,
flywheels, cranks, sprockets, and the like and controls the geometry of their motion.
Shafts are the elements that support rotating parts like gears and pulleys and in turn are
themselves supported by bearings resting in the rigid machine housings. The shafts
perform the function of transmitting power from one rotating member to another support
by it or connected to it. Thus, they are subjected to torque due to power transmission and
bending moment due to reactions on the members that are supported by them. Shafts are
to be distinguished from axles which also support rotating members but do not transmit
power. Axles are thus subjected to only bending loads and not to the torque.
Shafts are always made to have circular cross-section and could be either solid or hollow.
The shafts are classified as straight, cranked, flexible or articulated. Straight shafts are
commonest to be used for power transmission. Such shafts are commonly designed as
stepped cylindrical bars, that is, they have various diameters along their length, although
constant diameter shafts would be easy to produce. The parts carried by axle or shaft are
fastened to them by means of keys or splines and for this purpose the shaft and axle are
provided with key ways or splines. The bearings that support the shafts or axle may be of
sliding contact or rolling contact type.
Shaft Material
Good machinability.
Shafts could be made in mild steel, carbon steels or alloy steels such as nickel, nickel-
chromium or chrome-vanadium steels.
Heavily loaded shafts are often made in alloy steels which because of their high strength
would result in smaller diameters. These steels are amenable to heat treatment and
Stresses in Shafts
The following stresses are induced in the shafts:
Shear stresses due to the transmission of torque (i.e. due to torsional load).
Bending stresses (tensile or compressive) due to the forces acting upon machine
elements like gears, pulleys etc. as well as due to the weight of the shaft itself.
Stresses due to combined torsional and bending loads.
Maximum permissible working stresses for transmission Shafts
According to American Society of Mechanical Engineers (ASME) code for the design of
transmission shafts, the maximum permissible working stresses in tension or compression
may be taken as;
(a) 112 MPa for shafts without allowance for keyways.
(b) 84 MPa for shafts with allowance for keyways.
The maximum permissible shear stress may be taken as
(a) 56 MPa for shafts without allowance for key ways.
(b) 42 MPa for shafts with allowance for keyways.
A shaft with key ways used for horizontal shaft impact stone crusher.
Shaft Design for Stress ;The material used for ordinary shafts is carbon steel of grades
40 C 8, 45 C 8, 50 C 4 and 50 C 12. The mechanical properties of these grades of carbon
steel are given in the following table 4.9.
It is not necessary to evaluate the stresses in a shaft at every point; a few potentially
critical locations will suffice. Critical locations will usually be on the outer surface.
Possible Critical Locations, axial locations where:
Yield strength=350mpa
Power is constant=0.55KW
For shafts purchased under definite physical specifications, the permissible shear
stress (τ) may be taken 0.18 σu, whichever is less.
Mass of pulley=19.5N
T2=72.5N, R2=0.07m
60 × � 60 × 550
�= = = 14.59�� = 14596��� = 14.596��
2� × �2 2� × 360
888.1N 49.1N
19.6N65
= T1+T2+Pully weight
=796+72.5+19.6=888.1N
WA + W + WD − RB − RC = 0
Taking moment at B;
RC = 38N………………………….……… (4.9)
RB +RC =956.8
RB = 956.8 − 38.
RB = 918.8N
MB + MC = 0
Bending moment at A
MA = RB (0.065) = 59.9Nm
Bending moment at D
MD = RC (0.1m) = 3.8Nm
M = MA = 59.9Nm
Te = M2 + T2
Te = 59.92 + 14.590
Te = 3588 + 212.8
Te = 61.6Nm
π
Te = × τ × d3
16
16Te
d3 =
π(τ)
3
d= 4.901m3
=0.01698m=17mm
d = 17mm ≈ 25mm
The length of the key is obtained by considering the key in shearing and crushing.
Considering shearing of the key, Shearing strength (or torque transmitted) of the key
T == F ∗ 2 = (l × w) × τ × 2 = l × 7mm × 44 N
d d 25
2 ×
mm 2
T = l ∗ 3850N……………………………… (4.10)
T=16 × τ × d3 =16 × 42 N
π π
× 253
mm2
∴ T=T
So l ∗ 3850N=128854.4N mm
l =34mm
=l × 2 × 70 N
t d 5 25
T=l× 2 × σc × 2 2 × = l 2187.5N………. (4.12)
mm 2
128854.4Nmm= l 2187.5N
l=59mm
l =59mm=0.059m
From the standard dimension of radial ball bearing based on shaft diameter from (Gupta)
material used for bearing carbon steel.
Scrubbing of surface is necessary for proper cleaning. For different type of floors
different types of scrubbers are to be used. For stone flooring soft cloths, for cement
floors hard plastics are used.
2. It makes the flow of water towards the rear side where vacuum pump is fixed.
Material for scrubbing component
Required properties of material for the scrubbing component
Easy manufacturing
Good bending strength
Cheaper and abundantly available
Therefore through all the above necessity under consideration material selected for
the scrubbing component.
Plastic
Circular cross section
do −di 150−25
Thickness (t) = 2
= 2
=62.5mm
About 4.1 Nm torque is require for both middle and side scrubber to perform the task. We
need to make sure the scrubber is covered by the bucket. Beside the bucket should
perfectly prevent dirt and water from splashing in to the interior of the cleaner. The
reason why we need to use the bucket is because of these two reasons, first as mentioned
above it has to prevent the dirt and water from splashing into the parts and second and
most importantly it has to collect the dirt for the suction through the vacuum cleaner to
the tanks.
Excellent material insures at the bucket is not easily damaged and have a long service life
even in harsh conditions. Considering different criteria we select a sheet metal made
bucket. The length of the bucket is similar to the length of the scrubber.
Material:-Mild steel
Cross section :-rectangular hollow section standard dimension 30mm by 50mm
Where 539.35N is the total sum of the tension pulley load and weight of the, middle and
side scrubber.
49� + 956.5 − �� − �� = 0
�� + �� = 1005.5�……………………….….. (4.13)
Taking moment at A;
�� = 855.1�……………………………………..…… (4.14)
�� + �� = 1005.5�
�� = 1005.5� − 855.1�
�� = 150.4�
Bending moment at C
�� = �� (100��) = 85510���
Bending moment at B
� = �� = 85510���
��
�� =
��
317
�� = 2
=158.5mpa
�
�� =
�
b = 30
85510���
158.5��� = = 539.4��3
�
� ℎ3 − ℎ13
�=
6 ℎ
30 503 − ℎ13
�=
6 50
30 503 − ℎ13
539.4 =
6 50
ℎ13 = 119606��3
3
ℎ1 = 119606�3
ℎ1 = 49.27��
ℎ − ℎ1 50 − 46.27
�= = = 1.865�� = 2��
2 2
The handle simply a tube of 20mm diameter, the two ends are welded to the side frame.
It is banded in L-shape. The handle as a whole makes 300 with the horizontal. It has
effective height of 700mm, which is normal for average of man.
CHAPTER FIVE
Design Result And Cost Analysis
Length 700mm
Width 300mm
Frame Thickness 7.9mm
Width 725mm
Length 750mm
Middle scrubber Length 450mm
Inside diameter 30mm
Outside diameter 150mm
Corner scrubber Length 100mm
Inside diameter 30mm
Outside diameter 150mm
1. Prepare the main support frame attached the wheel shaft with the bearing on the lower
part of the frame and insert the wheels on the shaft, then join the caster wheel to the front
of the frame.
2. Prepare the main support frame and attach the bearing and the input shaft with the
pulley into the main frame.
3. Placed the shaft on the supporting frame through the bearing by fixing it with the large
pulley and the scrubber on it.
5. Attached the wheel shaft with the lower part of the frame and insert the wheels on the
shaft.
6. Insert the tank on the frame and attach them on the main frame then connect the pipe
with tank and dust collector. Finally we insert the prepared handle.
Cost of axle
mb = 0.00005495m3*7850kg/�3 = 0.4313575kg
$1=52birr
Cost =m*cost/kg
Cost of pulley
Mass=volume*density
cost=3.37birr/kg*1010kg/m3=300birr
Cost of belt
Cost of shaft
Mass=volume*density
ms = Vs * ƍs
Vb = 0.000414788m3
mb = 0.000414788m3*7870kg/m3
mb = 3.264kg
$1=52birr
Cost =m*cost/kg
=3.264kg *78birr/kg=254.592birr
Cost of key
V=l*w*t
V=0.000002065 m3
M=0.0162kg
$1=52birr
Cost =m*cost/kg
Cost of frame
Mass=volume*density
mf = Vf * ƍf
Af = 1500-1196= 304mm2
L= length of frame
W= width of frame
Vf = 0.0008968m3
mf = 0.0008968m3*7850kg/�3
mb = 7.03988 kg
$1=52birr
Cost =m*cost/kg
Cost of handle
Mass=volume*density
mh = Vh * ρh
Vb = 0.000094247m3
mb = 0.000094247m3*7850kg/m3
mb = 7.398kg
$1=52birr
Cost =m*cost/kg
CHAPTER SIX
This design can be used to clean any kind of flat space as the motors selected can
consume much less power so it will be the power saving and cost saves too. Effective
power given to the brush does number of cleaning tasks. The need of this project is
satisfied and with the help of machine, cleaning of the floor can be done easily. The
machine is flexible and effortlessly operated. The time required for cleaning has been
reduced.
During the design time, each of the major parts of the machine was well designed and
evaluated numerically and stress analysis gained from each part was safe. 2D and 3D
drawings are done depending on the values gained from the design analysis. Finally, the
assembly of the machine is done to visualize what the machine looks like by Solid work
2017 software and how mechanism of the machine is worked by simulation, thus the
product developed is fully operational and gives desired motion.
Thus, by using manually operated floor cleaning machine a clean surface i.e. free from
dirt and dust is achieved. As the desired effect is for dry and wet cleaning is done
simultaneously .The human efforts is also reduced to a great extent. The work of
sweeping and wiping is also saved. Overall, the concept is very much helpful and there is
scope of a lot of development in mechanical parts.
6.2 Recommendation
The machine is not capable of cleaning stair of any building because the machine
works on only flat surfaces so for the future, it is expected to add some futures
and mechanism be to solve this kind of problems.
Regular Maintenance for brush on scrubber is required.
The driving mechanism of the machine is operated manual labor, this will create a
stress on the operator to move the machine, so we recommend integrating
electrical driving system to the current design.
The machine cannot clean rough and bump surfaces so we recommend
developing such mechanisms to overcome this problem.
Finally, yet importantly, we recommend that by upgrading the motor capacity and power
delivering system to the scrubber we can make the machine to be used outside the indoor
to, like to clean towns and rough roads like Asphalts.
REFERENCE
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(2020). ’Design and Fabrication of Manually Operated Floor Cleaning Machine’.
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on teaching mechanical engineering design in Turkey. International Journal of
Technology and Design Education, 28(3), 843-866.
[5]. Khurmi, R. S., & Gupta, J. K. (2005).A textbook of machine design. S. Chand
publishing.
[6]. Liu, K., & Wang, C. (2013). A technical analysis of autonomous floor cleaning
robots based on US granted patents. European International Journal of Science and
Technology, 2(7), 199-216.
[7]. Riaz, M., Nur, O.,Willander, M., & Klason, P. (2008).Buckling of ZnO nanowires
under uniaxial compression. Applied Physics Letters, 92(10), 103118.
[8]. Roshan, D., Bhosle, O., Bhosale, G., Borse, A., & Bandsode, T. (2020).Bluetooth
Operated Vacuum and Floor Cleaner using Android Mobile.
[9]. JGUPTA, a textbook of machine design, eurasia: eurasia publishing house (pvt.) ltd.,
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[10].https://www.researchgate.net/publication/271156448_Design_and_Development_of
Floor_Cleaner_Robot_Automatic_and_Manual.
[11].https://www.hfmmagazine.com/articles/3468-floor-cleaning-machines-offer-
advanced-options
[12] .https://www.tennantco.com/en_us/solutions/robotic-cleaning-machines.
[13]. https://en.m.wikipedia.org/wiki/Floor_cleaning
[14] . https://www.researchgate.net/publication/324528763
ASSEMBLE DRAWING