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Chapter 1

Introduction towheelchair

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1.1 Introduction to wheelchair

As we enter the second millennium since the time of Christ there is an

increasing mindfulness of the need to focus technology on helping

people. This has been in part on account of many countries currently

experiencing what is referred to as an “aging population,” that is the

number of children born has continued to reduce over a long period of

time. The result of this along with many other factors has caused the

need for a reducing number of care worers to care for an increasing

number of persons.!ne speci"c area of need is that of providing

increased freedom in terms of mobility for the elderly or disabled. The

reasons being to provide an optimum #uality of life for the disabled or

elderly, and to reduce the load on care worers, the two aspects being

closely lined by the conscious sense of being a “burden”.

Autonomy in the area of mobility has always been highly valued, but is

sometimes impaired by some form of disability. $n many cases this results

in reliance on some form of external transport mechanism. $n this regard

traditional wheelchairs and powered wheelchairs continue to play a vital

role. %owever wheelchairs to date provide a high level of mobility only in

arti"cial or “barrier free” environments. That is there remains a

signi"cant gap between the obstacle negotiating ability of a wheelchair

and that of the average able bodied person. This aspect is perhaps most

apparent when considering stair&climbing. 'hile modern architecture and

new policies continue to mae newly built areas as “accessible” as

possible to persons with a wide variety of disabilities steps will always be

a reality in the “real world”.

 This thesis focuses on the study of stair&climbing capable mechanisms for

the elderly or

(isabled people.

1.2 History

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 The earliest records of wheeled furniture was an inscription found on

a stone slate in China and a child*s bed depicted in a frie+e on a ree

vase, both dating bac to the -th century C/. The "rst records of 

wheeled seats being used for transporting the disabled date to three

centuries later in China0 the Chinese used their invented wheelbarrow tomove people as well as heavy obects. A distinction between the two

functions was not made for another several hundred years, around 2)2

C/, when images of wheeled chairs made speci"cally to carry people

begin to occur in Chinese art. 3ee "gure 1.1.

Fig.1.1.History of machine

4ater dates relate to /uropeans using this technology during the erman

5enaissance.

 The invalid carriage or ath Chair seems to date from around 16-7. $n

1886, wheelchairs

9:rolling chairs:; were introduced to Atlantic City so invalid tourists could

rent them to enoy the oardwal. 3oon, many healthy tourists also

rented the decorated :rolling chairs: and servants to push them as a

show of decadence and treatment they could never experience at home.

%arry

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?ig.1.)9'ooden wheelchair dating to the early part of the )7th century;

 The two saw the business potential of the invention and went on to

become the "rst mass&manufacturers of wheelchairs@ /verest and

 B: thic. The handrims have a diameter normally only

slightly smaller than the wheels they are attached to. ost wheelchairs

have two push handles at the top of the bac to allow for manual

propulsion by a second person.

!ther varieties of wheelchair are often variations on this basic design,

but can be highly customised for the userDs needs. 3uch customisations

may encompass the seat dimensions, height, seat angle 9also called seat

B

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dump or s#uee+e;, footrests, leg rests, front caster outriggers, adustable

bacrests and controls.

Types of wheelchair:

1.>.1 anual wheelchairs

 anual wheelchairs are those moved by the user or an attendant. Theself&propelled chairs usually have rear wheels of between )7 and )-inches in diameter "xed to an axle and positioned so that users canmove them by pushing down or pulling bac the push rims. The userscan therefore travel forward and bacward at speeds dictated by theamount of force they are able to apply.y controlling the push rims, users

can also turn left or right and negotiate small dips and rises that lieahead. To operate manual wheelchairs successfully, however, users musthave a good standard of muscular ability and coordination in their armsand shoulders. Alternative methods of propulsion include foot pedals andlevers wored by hand.3ee "g1.>.

?ig.1.>. anual wheelchairs

1.>.). anual Transit wheelchairs

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  anual transit chairs generally have small rear wheels without pushrims. These wheelchairs are most liely to be seen in buildings such asairports and hospitals where porters act as attendants. These are alsocalled manual transfer chairs.As shwon in "g.1.B.

?ig.1.B. anual Transit wheelchairs

1.>.>/lectric wheelchairs

  Eower 9/lectric; 'heelchairs are also called “motori+ed wheelchairs”and sometimes abbreviated /E' 9electric powered wheelchairs;.Eowered by an electric motor, these chairs are navigated by controlssystems. $ndividuals too wea to maneuver a manually poweredorstandard wheelchair bene"t from power chairs, as do individuals withheart andor breathing conditions. Eower electric wheelchairs are

intended for use in everyday life and there are power wheelchairs madespeci"cally for indoor and outdoor use.

/lectric powered wheelchairs are ideal for anyone who does not possessthe strength or ability to cope with a manual chair. 5echargeablebatteries mounted under the seat supply power to electric motors thatdrive either two or all four of the wheels. As with a car, the diFerent drive

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arrangements determine the way that the wheelchair moves andmanoeuvres.

$t is important to now for what conditions a chair is designed for. Gsingindoor electric wheelchair outdoors runs the ris of potential damage to

the frame, front fors, and motor could occur. The wheelchair industryhas standards for brae eHciency, energy eHciency, overall si+e, speedand acceleration, impact testing, obstacle maneuverability, and controlsystem ergonomics.

 The batteries come in three types@ wet&cell, gel&cell and A 9absorbedglass mat;.

• 'et&cell batteries are the lightest, cheapest and least liely to be

overcharged. They tend to lea, however, so cannot be taen on aplane.

• el&cell batteries are heavier but do not lea. They last longer than

wet&cell batteries and are accepted for air travel.

• A batteries are heavy and expensive, but they are suitable forairplanes, are shoc&resistant and lea&proof, and do not re#uiremaintenance.

 The above batteries may have to be charged by a separate unit, but

most modern electric wheelchairs can simply be plugged into an electricsocet.Apart from the choice of batteries, there are options for managingthe direction and speed of electric wheelchairs. any have a small oystic that is mounted at the end of an arm rest or on a bar that swingsin front of the user once he or she is seated. !thers have tubes intowhich the users blow or suc to control the chair*s movements.

 The level of disability experienced by electric wheelchair owners is alsoreIected in the design of other features. These include

• tilting mechanisms0

• reclining bacs0

• seat, leg and arm elevators.

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ost of these functions are controlled by small electric motors and allowusers to mae themselves as comfortable in the chair as possible. Asshown in "g.1.2.

?ig.1.2.electric wheelchair.

1.>.B 'heelbase

A wheelbase chair, otherwise nown as a scooter, has four small wheelsextending from a low platform. The type of chair mounted on thisplatform varies according to the disability and needs of the user0 someare even molded from a cast taen of the user*s most appropriate sittingposition.

!ne of the advantages of the wheelbase machine is that the chair canswivel and allow the user to mount and dismount from either side. Adisadvantage is that the user must maintain a rigid posture when driving. This means that wheelbase chairs are rarely suitable for the severelydisabled.

 The controls of the wheelbase chair are mounted on a frame thatcurves upward from the front of the platform to a height and position

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convenient for the user. A hori+ontal steering bar is attached across thetop of the frame.as shown in "g.1.-.

?ig.1.- wheelbase.

  1.>.2 3ports chairs

3ince the 1=67s, disabled athletes have had an increasing array of speciali+ed wheelchairs to help them achieve the most from their chosensport. These chairs can loo very diFerent from each other, but whatthey usually have in common is

• lightweight frames made from composite material0

• solidity 9which means that they do not fold;0 and

• enhanced stability for sudden turns 9this is achieved by using

angled wheels;.

3ports wheelchairs or recreation wheelchairs are specially designed forathletes with disabilities who are competing in sports that re#uire agilityand speed such as basetball, tennis, rugby or racing. These very speci"cchairs usually do not fold and are not used in everyday life. (epending

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on the sport, the chairs vary in design. The handcycle replaces theconventional bicycle with hand&powered peddles instead of leg poweredpeddles. Court chairs come with a variety of features including@ frontbumpers, wings, spoe protectors, castor protectors, adustable tricfootrests, and more. 5acing chairs are for exactly that, racingJ Their slee

designs allow competitors to rush across the "nish line. All terrainwheelchairs enable exploration of oF&road, unpaved, bumpy, gravelareas. The si+e truly depends on the sport. There are many modi"cationsand adustable features on this type of wheelchair. 3ports wheelchairsare made from lightweight metals in order for the occupant to power it#uicly and easily. aterials such as carbon steel frames, adustablefootrests, adustable tension upholstery, aluminum pushrims, stainlesssteel or titanium axles are features of these very speci"c wheelchairs,see "g.1.6.

?ig.1.6.sport chairs.

1.>.2 3tand&up

3tand&up wheelchairs are "tted with a hydraulic pump that lifts andtilts the seat, thereby enabling the user to :stand up: and yet be fullysupported. This is an invaluable feature if the user needs to reach anitem on a shelf either at home or while out shopping. 3ee "g.1.8.

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?ig.1.8.stand&up wheelchair

1.>.- 3tair&climbing wheelchairs

Climbing stairs is the ultimate test for a wheelchair, and there are anumber of solutions available.

• attery&operated supports at the bac that act as stabilisers as the

chair climbs.

• A series of Iexible wheels turning within rubber tracs that grip the

steps.

• $ndependent stair&climbing wheelbases onto which the wheelchair

is fastened.

ost stair&climbing chairs do still need a third party attendant.

Alternatively, the wheelchair user must be able to grasp a suitablehandrail. The iot made a lot of headlines a few years ago, but it is nolonger sold.as shown in "g.1.=.

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?ig.1.= 9The nationDs "rst stair&climbing wheelchair, the iot)

1.>.6 each wheelchairs

A beach wheelchair is immediately recogni+able because of its broadwheels that enable it to ride smoothly over sand without sining. 3omebeach resorts now provide not only wheelchair accessibility but also oFerbeach wheelchairs to disabled clients.see "g.1.17.

1)

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?ig.1.17.beach wheelchair.

1.4 Motivation

  The presence of stairs will most likely always be a reality in the real world, because of 

the high level of spatial efficiency they provide when connecting areas of differing vertical

elevations.

Stairs do present an increased degree of danger compared to such as gentle slopes but this

must to some degree by necessity be simply taken into account. For example in the planning

of any new buildings the target users should be considered. learly for public amenities,

such as wheelchair users should be considered.

!n some places where they do not take this consideration in mind a problem for typical

wheelchair will be appear that is it can not climb the stair so the person will not be able

toreach the desired location .

This problem motivate us to think of a new type of wheelchair that has the ability of 

climbing the stairs.

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1.5 Objectives.

1. /ase of movement.). !vercome the obstacles faced during movement.

>. 3tair&climbing ability.B. Autonomous stair&climbing possible 9autonomous stair&climbing

wheelchair only;.2. 3uitable to most outdoor stairs and some indoor stairs.-. 3imple operation 9non&trac based stair&climbing mechanisms;.6. /ase the movement in the rugged places.

1.6 Methodology

  "e studied different types of wheelchair theoretically and reali#ed their abilities,

applications and the differences between them, !n order to get the maximum number of 

advantages and trying to avoid their disadvantages.

1B