SHANGALI RODRICK

PROJECT TITLE:

DESIGN AND MANUFACTURING

OF A

WHEELCHAIR-TRICYLE ATTACHMENT

Rodrick H. Shangali

B Sc. Mechanical. Eng

OVERVIEW OF PRESENTATION

• Introduction

• Background of the project

• Problem statement

• Project objectives

• Literature review

• Methodology

• Analysis

• Design

• Manufacturing and Testing

• Results

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INTRODUCTION

• A hand tricycle works in the same way as a bicycle as it

uses a chain system with pedals to drive the wheels.

• Except, in the case of a hand tricycle, the chain is

attached to hand pedals, allowing the user much more

efficient propulsion than would be provided from the

push rims on a wheelchair.

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BACKGROUND OF THE PROJECT

In most developing countries, people with disabilities do

not have the opportunity of adapted roads, ramps, or

handicapped accessible transportation.

As a result, wheelchair users often rely solely on their own

power for both long and short distance travel.

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CONTD…

Mobility aids currently used do not fully suit user needs;

wheelchairs are exhausting to push on rough ground,

while hand-powered tricycles, which are more efficient

to propel, but they are too large to use in the house.

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PROBLEM STATEMENT

The requirements of the two different environments exert mutually

exclusive functional demands on the wheelchair systems.

Crucial points being described are such as unable to use for

both indoor/ outdoor activities

Some of the designs are complex and expensive

Performance is low for manual wheelchair

They require large usage of human energy (increase tiredness)

and coverage of distance.

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PROJECT OBJECTIVE

MAIN OBJECTIVE

The main objective was to design and manufacture a cost

effective wheelchair tricycle attachment for easier

accessibility and increased performance to the wheelchair

user.

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CONTD…

SPECIFIC OBJECTIVES

The specific objective was to:

• Investigate the existing driving systems for both wheelchairs

and tricycles.

• Design and manufacture a wheelchair tricycle attachment

for better accessibility and performance of a wheelchair user.

• Test and evaluate the developed wheelchair tricycle

attachment.

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LITERATURE REVIEW

Each wheelchair user has his/her unique set of needs.

A wheelchair is required to take into account the

following wheelchair users requirements:

• Home environment as at rural, urban, crowded and flat areas.

• Disability, i.e. Amputee, Polio, Spinal Injury, etc.

• Lifestyle, i.e. do they work, travel long distances, keep to the

house, or participate in sports.

• Economic situation (ability to afford their daily living expenses)

(Ham (1998) and Cruz ( 2002)) SHANGALI RODRICK

CONTD…

The Clip-on Tricycle Attachment is an active style hand

powered drive allowing:

• Quickly convert the wheelchair into a tricycle

• It helps the user to travel greater distances with less effort,

• Easy to replace or repair and uses many standard bicycle parts.

• Assembling and dissembling for recycling or reuse.

• The tricycle drive, together with the wheelchair, is easy to carry

on most forms of transport. (Kirby and Cooper (2007))

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METHODOLOGY

a) Survey and data collection

b) Interviews involves Users, Manufactures,Experts,Centres for

disabled peoples Sponsors of disabled peoples for both

wheelchair and tricycle, Supplier and TBS Standards,

c) Information analysis

d) Observations, User’s ,Manufactures and Supplier’s

e) Design process/ procedures

f) Manufacturing, Testing and Evaluation

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PROJECT AREA

• The project was conducted at TATCOT in Moshi,

Tanzania.

• Also it involved collaboration and co-operation with

other company or societies, such as KASI in Moshi,

DAGE and TDTC, both in Dar-es- salaam.

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COLLECTED INFORMATION

DAGE:

ONE OF

THE

TRICYCLE

DESIGN

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ANALYSIS

Design Information and Responces

The assessment was to inspect the current state of

wheelchair technology from all angles through

interviewing the primary parties involved with

wheelchair design, manufacturing and users.

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CONTD…

The results were been grouped in terms of interviewed:

• Individual wheelchair users

• Wheelchair advocacy groups

• Wheelchair manufacturers.

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A. USER RESPONCE

In all, 30 physically disabled people who were interviewed:

Causes of physical disability

• Polio was the most common disability observed. Most polio survivors

interviewed contracted the virus early in life.

• Survivors of birth defects and polio, who made up 63% of people interviewed,

had been disabled for nearly their whole life.

• In comparison to the spinally injured, who became disabled typically later in life

(~20 years old), birth defect and polio survivors had their entire life to

acclimatise to being disabled.

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Causes of disability

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23%

63%

14% Birth

Defect

Polio

Spinal

Injury

Pre-wheelchair mobility

• As a result of the majority of interviewees becoming

disabled early in life with a birth defect or polio, most had to

resort to crawling as a means of mobility before

obtaining a wheelchair or tricycle.

• 66% of the interviewees were crawling before obtaining

their current mobility aid.

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Travel before current mobility aid

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0%

20%

40%

60%

80%

Crawling Cane Crutches Push cart

No. of

Inte

rvie

wee

Means of transportation before current WC/trike

CONTD…..

• The average age of obtaining a first wheelchair or

tricycle was 15-20 years old.

• As a result, most people who went to school or had a

job before the age of 22 were forced to crawl as a

means of travel, while others were simply unable to

attend school or obtain a job because of distance.

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Age when first mobility aid obtained

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0%

10%

20%

30%

40%

50%

60%

70%

0-20 21-30 31-40 40-49 50+

No. of

Inte

rvie

wee

Aged when first mobility aid obtained

Mobility aid usage after obtaining

wheelchair or tricycle

• Most of the interviewees needed to travel multiple

kilometers per day, with 50% travelling between 0 to

5km.

• For long distances, a tricycle requires much less power

than a wheelchair. As a result, tricycles were observed

to be more popular than wheelchairs

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Daily travel distance

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0%

10%

20%

30%

40%

50%

0 to 5 Km 6 to 10

Km11 to 15

Km 16 to19Km >20 km

No

. o

f In

terv

iew

ee

Distance travel to work/ school

Wheelchair or tricycle purchasing

ability

• One major problem observed during the assessment

was the inability of many people to purchase their

own mobility aid.

• Only 17% of those interviewed were able to purchase

their own mobility aid

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Sources of funds for current mobility

aid

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0% 10% 20% 30% 40% 50% 60% 70%

Yourself/family

Gov't

NGO/Church/Mosque

Hospital

Business/Donation

Chair manufac.

No. of Interviewee

Wh

o p

aid

fo

r cu

rre

nt

WC

/tri

ke

Locations of wheelchair/Tricycle repair

• Bicycle shops were the most common location of wheelchair and

tricycle repair reported during the assessment. Part availability

was a serious issue in how repairable chairs were.

• The most common complaint about chairs was that spare parts

are not available.

• Tricycles are easily repaired at bicycle shops because they are

primarily built from bicycle parts.

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Distribution of mobility aid repair

locations

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At manufact 23%

Bicycle shop 63%

Yourself 14%

B. Manufacturer Responce

• Decrease prices of WTTC wheelchairs to compete with tricycles.

Right now there is a $100US price difference between WTTC

chairs and Tanzanian tricycles. UWZ is able to produce

wheelchairs for just $140US.

• Use of bicycle parts and outsourcing lowers prices and also makes

the wheelchairs and tricycles easier to repair by bicycle workshops.

• The strength of many wheelchair and tricycle designs should be re-

calculated to determine if they can sustain stresses caused by

environments in developing countries.

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CONTD ……

• Bearings should be correctly mounted, as to not shorten their life.

A wheelchair with tricycle attachment should be investigated as a

possible product for WTTC graduates to produce.

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C. Advocacy Group Responce

• Most of the organizations interviewed do not purchase

wheelchairs or tricycles, and instead rely on donations. Those that

do buy chairs are reported below, along with details about how

many WCs they buy and how much the organizations spend on

chairs and tricycles.

• For few organizations are able to purchase chairs, but

international NGOs like Lilana funds are willing to subsidize

purchases.

•

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ANALYSIS

• Feedback from current wheelchair and tricycle users, and

assessing the pitfalls of current mobility aid technology.

• A next-generation wheelchair should be designed in the

future. The most versatile type of mobility aid would be a

wheelchair with a tricycle attachment.

• The tricycle attachment concept was very popular with

interviewees and wheelchair workshops. This new type of

wheelchair would meet the short and long distance

mobility needs of Tanzania’s disabled.

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CONCEPT 1

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CONCEPT 2

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Evaluation and Concept Ranking. The evaluation and ranking of the concepts using Rating and

Weighting Matrix Method was through the following criteria;

• Easy to manufacture

• Low production cost

• Reasonable product price

• Easy to operate

• Simple design

• Efficiency

• Ergonomics

• Aesthetics

• Weight

• Availability of material

• Safety

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CONTD…

To fully serve wheelchair users, the following features should be

included in the next-generation African wheelchair with tricycle

Attachment

• 3-wheeled: A three-wheeled design is best suited for the rough

terrain of both urban and rural Tanzania. Three wheels are always

in contact and kinematically constrained with the ground, making

the chair very stable on rough surfaces.

• Foldable frame: For trips longer than what is possible with the

tricycle attachment, the wheelchair must be stowable on busses.

Allowing the frame to fold gives the chair the functionality of a 3-

wheeler with the packability of a folding 4-wheeler.

SHANGALI RODRICK

CONTD…

• Stowable tricycle attachment: The wheelchair should

have an area or fixture on which to stow the tricycle

attachment. This area could possibly be on the back of

the chair. The rider should have the option of keeping

the tricycle attachment affixed to the chair, as there may

be situations where leaving it alone might not be safe or

feasible.

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DESIGNS

All the design sketches, parts and assembly was done

Under design package , solidwork 2005 and solidwork

2012.

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MANUFACTURING

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CONTD…

MAIN

FRAME

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CONTD…

PAINTING

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TESTING THE ATTACHMENT TO

FIT

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ATTACHEMENT MOUNTING

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ELEVATION POINT(TRICYCLE)

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The bill of material was formulated depend on detail

and assembly drawing of various components, table

below shows requirement and cost of various

components of the designed wheelchair tricycle

attachment.

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Bill of quantity (BOQ)

Table .Bill of Quantities (BOQ) S/N Name Specification/Size Quantity Unity Price Amount (T.shs)

1 Used bike frame Gear front frame

assembly

2 pc 50,000 100,000

2 Pedal hub bearing

assembly

1 pc 10,000 10,000

3 pedal 1Pair (L= 170mm) 2 pc 10,000 20,000

4 Bike chain Length (1820 mm) 1 pc 5,000 5,000

5 Bike sprocket 30 teeth 1 pc 5,000 5,000

6 Bike sprocket changer 28,20,12 and 10

teeth

1 pc 5,000 5,000

7 Bolts and nuts M 12x25mm 3 Kg 2,000 6,000

8 Bolts and nut M8x58.1mm 3 Kg 2,000 6,000

9 Tyre 1 pc 10,000 10,000

10 Brake assembly 1 pc 8,000 8,000

11 Round rod 2 pc 20,000 40,000

12 Flat bar 10x2x50 2 pc 15,000 30,000

13 Wheelchair 3 wheeler 1

14 Shaft 2 pc 40,000 80,000

TOTAL COST 325,000/=

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Cost Estimate of the Designed

Wheelchair tricycle attachment Cost estimate of the Wheelchair tricycle attachment is

calculated based on the costs incurred to which a profit

margin is added. Product costing at TDTC is guided by

the following formula

From the basic formula, Let

A= Contingency (100% of material cost)

B= Machine charge (10% of material cost)

C= Labour charge (30% of material cost)

D= Overhead cost/institutional cost [15% of (A+B+C)]

Thus; cost of the pin mill machine will be T.Shs 500,000

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Thank you for

listening