DESIGN AND MANUFACTURING OF A...
Transcript of DESIGN AND MANUFACTURING OF A...
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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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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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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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.
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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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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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