Design And Fabrication Of Mechanical Lawn Mower

ABSTRACT

This work is titled design and fabrication of a lawn mower. A lawn mower is a machine that uses one or more revolving blades to cut a lawn to an even height. The blades may be powered either by hand; pushing the mower forward to operate the mechanical blade(s), or may have an electric motor or an internal combustion engine to spin their blades.

Two main styles of blades are used in lawn mowers. Lawn mowers employing a single blade that rotates about a single vertical axis are known as rotary mowers, while those employing a multiple blade assembly that rotates about a single horizontal axis are known as cylinder or reel mowers.

The blade sits within a casing called a deck, which keeps the grass and other objects from flying in all directions when struck. Typically, the deck rides on four wheels, with a motor sitting on top of it and a bag attached to it to collect the cut grass.

The aim of this work is to design and fabricate a machine that can be used to cut lawn grasses.

LIST OF SYMBOLS

G         =          Density

d          =          Diameter of the shaft

D         =          Diameter of the blade

W        =          Omega Angular Speed

J           =          Second Moment of inertia

M         =          Mass of the object

T          =          Torque

TI        =          Pie

V         =          Velocity

F          =          Cutting force

P          =          Power

s          =          Shear stress

å         =          Strain

L          =          Length

B         =          Breadth

H         =          Height

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0      INTRODUCTION

1.2      PROJECT MOTIVATION

1.3     BACKGROUND OF THE PROJECT

1.4     SCOPE OF THE PROJECT

1.5      IMPORTANCE OF THE PROJECT TO SOCEITY

1.6      AIM AND OBJECTIVE OF THE PROJECT

1.7      PURPOSE OF THE PROJECT

1.8      IMPROVEMENT IN ECONOMY

1.9     SIGNIFICANCE OF THE PROJECT

1.10   LIMITATION OF THE PROJECT

1.11   PROJECT ORGANIZATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1      DESCRIPTION OF A LAWN MOWER

2.2         HISTORICAL BACKGROUND OF THE PROJECT

2.3      REVIEW OF DIFFERENT TYPES MOWER

CHAPTER THREE

3.0     METHODOLOGY

3.1      MACHINE OPERATION

3.2      MATERIALS AND METHODS

3.3      METHODOLOGY ADOPTED FOR ASSEMBLING OF LAWN MOWER

3.4      METHODS OF USE

CHAPTER FOUR

RESULT ANALYSIS

4.0      CONSTRUCTION PROCEDURE AND TESTING

4.1      CASING AND PACKAGING

4.2      ASSEMBLING OF SECTIONS

4.3      TESTING OF SYSTEM OPERATION

4.4     ECONOMIC OF THE PROJECT

4.5      VIABILITY OF THE PROJECT

4.6      RELIABILITY OF THE PROJECT

4.7      MAINTAINABILITY

4.8      PROJECT EVALUATION

4.9      MAINTENANCE

4.10   RESULTS AND DISCUSSIONS

COST ANALYSIS

CHAPTER FIVE

5.0      CONCLUSION

5.1      RECOMMENDATION

CHAPTER ONE

1.0                                          INTRODUCTION

In the past, cutting of grasses in the schools, sports track, or field, industries hotels, pubic center, etc was done by cutlass this method of manual cutting is time consuming a s it is human effort that is needed for cutting, there was also inaccuracy in cutting level using the manual cutting system.

Apart from all these old method of cutting there is also risk of accident.The problems of the manual was meant to be overcome with the aid of this project (the construction of a mechanical lawn mower) which is used for cutting of grasses to equal height or level for speedy cutting.

This project lawn mower, is also the accident free as well, it reduced labour and also reduced number personnel that is needed in a particular operation, it also reduced man power as it an internal combustion engineer that dose the actual cutting while the operator provides the efforts, great portion of land can easily be cut with lawn mower.

Again to encourage beauty in our environment this project was embarked on to help in keeping our environment clean because most labourers are finding it difficult in handily tool for gasses cutting.  It is also used for cutting sports field, (like foot ball pitch as well as crowns in hotel and business premises so this project reduces human effort and should be encouraged in school, hotel, business area, etc although mowers can be of electric type too, but we decided to fabricate a mechanical type to overcome the problem of electricity and as such this our lawn mower can be used every where even were there is no electricity.

1.2                                   PROJECT MOTIVATION

Early before now, West Africa as a whole, the peasant farmer depends on the hoe and cutlass for practically all farm operation.  There tools vary in shape and size from place to place in the high forest zone of Nigeria the small farmer must clear thick bush every three or four years.  All this job is being done either hoe or cutlass for weeding of farm land.  These farm operation depend entirely on the energy of the farmer using the tools which he has at this disposal.   This inability that facing the farmer, has triggered these project group to research into the lasting solution to the problem.

Also, with meant development in the country, daily labour in farm operation is highly exorbitant for the farmer to afford but with these project (mechanical lawn mower) this problem of high payment of local labour can lead to reduction importation cost from Germany USA of this machine Nigerian with high profitability to the farmers.

1.3                          BACKGROUND OF THE PROJECT

The lawn mower is a mechanical device that literally shaves the surface of the grass by using a rapidly rotating blade or blades. For centuries, grass was cut by workers who walked through pastures or fields wielding small, sharp scythes. In addition to being tiring and slow, manual cutting was ineffective—the scythes worked well only when the grass was wet. The first mechanical grass-cutting device appeared in 1830, when an English textile worker named Edwin Budding developed a mower allegedly based on a textile machine used to shear the nap off of cloth. Budding’s cylindrical mower was attached to a rear roller that propelled it with a chain drive, and it shaved grass with a curved cutting edge attached to the cylinder. He created two sizes, large and small. The large mower had to be drawn by horses, whose hooves were temporarily shod with rubber boots to prevent them from damaging the turf; the head gardener at the London Zoo was among the first to purchase this model. Budding marketed the smaller mower to country gentlemen, who would, he claimed, “find in [his] machine an amusing, useful and healthful exercise.”

Mechanized grass cutting was evidently slow to catch on, perhaps because Budding’s mower was quite heavy in addition to being inefficiently geared. Only two lawn mower manufacturers exhibited their machines at England’s Great Exhibition in 1851. However, several decades later the new machines experienced a surge in popularity due to the interest in lawn tennis that arose in England during the late Victorian period. Before the turn of the century, Budding’s initial designs were improved. Weighing considerably less than their predecessors and based on the side wheel design still used in today’s most popular mowers, these refined machines were soon visible in yards throughout England.

The earliest gas-driven lawn mowers were designed in 1897 by the Benz Company of Germany and the Coldwell Lawn Mower Company of New York. Two years later an English company developed its own model; however, none of these companies mass produced their designs. In 1902 the first commercially produced power mower, designed by James Edward Ransome, was manufactured and sold. Although Ransome’s mower featured a passenger seat, most early mowers did not, and even today the most popular models are pushed from behind.

Power mowers are presently available in four basic designs: the rotary mower, the power reel mower, the riding mower, and the tractor. Because the rotary mower is by far the most common, it is the focus of this entry. Pushed from behind, rotary mowers feature a single rotating blade enclosed in a case and supported by wheels. As the engine turns, it spins the blade. The blade whirls at 3,000 revolutions per minute, virtually 19,000 feet (5,800 meters) per minute at the tip of the blade where the cutting actually occurs. The best rotaries feature a horn of plenty (cornucopia) or wind tunnel shape curving around the front of the housing and ending at the discharge chute through which the mown grass flies out. Self-propelled models are driven by a chain or belt connected to the engine’s drive shaft. A gearbox usually turns a horizontal axle which in turn rotates the wheels. Some models have a big chain- or belt-driven movable unit that rises up off and settles down on the wheels.

1.4              SCOPE OF THE PROJECT

Based on the developing countries, technology in farm operation is highly increased.  It is clear that developments in farm machinery in West Africa started far back 1960.  This project must related to the social and ecological condition prevailing in different parts of this great region at the present time two trends a re apparent.

1. Increase in the use of tractors and large agricultural machinery of farms of large extent both in the high forest and savanna zones, but particularly in the latter.
2. The increased use of animal power and small machines on peasant farms operation in West Africa will become increasingly mechanized, and that stage of mechanization mechanized, and that stage of mechanization which lies between the hoe and cutlass on one hand and the tractor combine harvester on the other is referred to as intermediate technology.

1.5       IMPORTANCE OF THE PROJECT TO SOCEITY

Generally this project (mechanical lawn mower) has a great effect towards development and maintenance of any community in the societies which one nominated below.

1. Cutting grass of secondary primary and tertiary field thereby reducing human effort needed.
2. Great portion of farmland can easily cut or brushed with lawn mower in one day.
3. This project reduced number of personnel that needed in a particular farm operation.
4. To reduce manpower
5. To improve the economy of the country
6. Provisions of foreign exchange in the country
7. t reduce importation cost t o our country (Nigeria)
8. It encourage pupils, and student to be regular and the school because no more cutting of grass with cutlass by pupils or students.

1.6       AIMS AND OBJECTIVES OF THE PROJECT

In the past, several investigation w ere made in the lawn mower industry at USA, Germany etc. Nigerian market, from which this production is a development of already existing ones.  It was localized to smite our environments condition aim and objectives of the investigation on the project are nominated below. The design objective is to come up with a mower that is portable, durable, easy to operate and maintain. It also aims to design a self- powered mower of electrical source; a cordless electric lawn mower. The heart of the machine is a battery-powered DC electric motor. It comprises of a system of speed multiplication pulleys which drive the cutting blades and the charging unit comprising of a 12V alternator and a lift mechanism meant to alter the height of cut. This is achieved by means of a system of pulleys with minimal slip effect; collapsible blades to reduce the common problem of wear. The use of collapsible blades and incorporation of an alternator for recharging the battery make the design unique such that no engine is involved. Performance test gave a cutting efficiency of 89.55% with 0.24kN human effort. Thus, the machine is considered highly efficient and is readily adaptable to different cutting conditions.

1.6.1    REDUCTION OF LABOUR COST

In application of lawn mower machine in any government field and farm land causes seriously reduction in number of labour needed in the maintenance of the yard, brushing and clearing of the grass but with aid of lawn mower machine, the job is easily performed without much wasting of time.  This project IMT can get the yard well cutted and cleared.

1.6.2                       IMPROVEMENT OF FOOD PRODUCTION

 Local farmer can embark on maintenance of 100 hectares of farm land with aid of lawn mower machine.  This project will extract some lazy farmer to embark on farming operation, also many people will developed interest and rendering agricultural engineering or course related to farm.

1.6.3    TIME FACTOR

The production of this project (lawn mower machine) brings reduction in man hour consumed in cutting of grass which is being improved using lawn  mower machine which employed some minute of an how for  the job.

1.7                               PURPOSE OF THE PROJECT

The purpose of the work is to fabricate a mechanical device that literally shaves the surface of the grass by using a rapidly rotating blade or blades.

1.9                                IMPROVEMENT IN ECONOMY.

Having farmer embark on large farm land for production of food to the citizen birth aid of lawn mower machine but not hand tools is bound so produce supply enough quantities food to market which extract improvement of country and also ensure stability and the foreign exchange.  Also boosting of employment to the youth of the town.

1.10                                         LIMITATION OF THE PROJECT

A 2001 study showed that some mowers produce the same amount of pollution (emissions other than carbon dioxide) in one hour as driving a 1992 model vehicle for 650 miles (1,050 km). Another estimate puts the amount of pollution from a lawn mower at four times the amount from a car, per hour, although this report is no longer available.

Mowers also create significant noise pollution, and could cause hearing loss if used without hearing protection. This can be avoided through the use of reel mowers or by using cheap, easily obtainable hearing protection such as earplugs or earmuffs.

1.11                     PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to this study. In this chapter, the background, project motivation, significance, objective limitation and problem of this study were discussed.

Chapter two is on literature review of the study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.

CHAPTER FIVE

CONCLUSION

Lawn mower is a machine that uses one or more revolving blades to cut a lawn to an even height. The blades may be powered either by hand pushing the mower forward to operate the mechanical blade(s), or may have an electric motor or an internal combustion engine to spin their blades. Some mowers also include other abilities, like mulching or collecting their clippings. An electrical Lawn Mower is more suitable & easy to use than the lawn mower with an engine, so we are making an electrical lawn mower with an electric motor, which is providing the high speed rotation to the blades. Cordless electric mowers are powered by a variable number (typically 1-2) of 12-volt rechargeable batteries. Typically, more batteries mean more run time and/or power. Batteries can be in the interior of the lawn mower or on the outside. If on the outside, the depleted batteries can be quickly swapped with recharged batteries. Cordless mowers have the maneuverability of a gasoline powered mower and the environmental friendliness of a corded electric mower

5.2                                                    RECOMMENDATION

The design of an electrical lawn mower contents a blades, bed knife, body frame, wheels, push handle, bag, & motor. The power system there are many Options, but we are using rechargeable battery powered motor, which is attached to the cutting blades. Sizing the battery will depend on what we are powering, specifically the motors. Like batteries, there is a range of motors to choose from. We went with 24 volt motor with integrated gear heads. We recommend that proper mentanence must be carried out whenever it is needed. In future we can add the Remote sensors to the Lawn Mower to operate it by the remote control.