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1 Cover Page
2 Contents
3/4 Project Objectives & Gantt Chart
5 Introduction
6-9 Product Design Specification
10 Identifying a Problem
11-13 Research Strategy
14-15 Product Research & Current Technology
16-18 Identifying the best materials suited to bicycle design
19 Components needed in a bicycle/ Bicycle Standards
20-21 Folding Mechanism
22-23 Folding Mechanism from a Brompton
24 Cycling Biomechanics
25 Ergonomics
26 Practicality
27-28 Pro Forma
29 DEVELOPMENT
30-31 Concept Sketches
32 Concept evaluation
33-35 3D Modelling & Detailed Drawing
36-37 EVALUATION
40 Bibliographies
41-45 Bicycle Visuals
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PROJECT OBJECTIVES
Planning
Creation of design brief
Creation of Gantt chart
Research
Creation of objectives
Creation of P.D.S
Identification of materials and recourses
Identification of possible verification strategy
Identify styles and standards
End of planning
Development
Concept generation
Concept A
Concept B
Concept C
Concept D
Concept evaluation
Development Report
Creation of prototype
3d cad model
Detailed drawings, part and assembly dwg
3d animation
Presentation
End of development
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EVALUATION
Identify strengths and weaknesses
Identify action taken for unforeseen circumstances
Review of project brief, have plans been met
Identify skills and knowledge gained
3 action points for consideration
Production of an oral presentation
End of evaluation and project
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Introduction
The history of the folding is a bit of a grey area for there is the issue of what
exactly constitutes a "folding" bike. There are a few historical references to
so-called folding bikes but the descriptions of them sound more like
"disassemble-able" bikes rather than true folders wherein the frame actually
collapses, there are competing claims from several inventors in different
countries vying to be the first inventor of the folding bike. Most of these
claims can't be documented in a convincing manner but that's not to say
that they aren't necessarily true.
The actual first inventor of the folding bike may never be known with absolute
certainty. One of the first credibly documented inventions of a folding bike is
by an American, Michael B. Ryan in his U.S. patent filing dated Dec 26, 1893
and issued on April 17, 1894 as patent number 518,330. A excerpt from the
patent reads "The principle object of my present invention is to produce a
bicycle, so constructed that it can be easily folded and thus take up less
space in length when not in use or when transported or stored."
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Product Design Specification
Title: - Folding Bicycle
1.0 Performance
1.1 The product must be height adjustable to promote ease of use.
1.2 The product must be sufficiently stable to promote safe use of the
product.
1.3 The product should be compact, foldable, and easily portable to
promote ease of use.
1.4 The product should ad heir to all British Standards for bicycle safety
2.0 Environment
2.1 materials surface`s are 99.9% corrosion resistant.
3.0 Product Life Span
3.1 The final product is expected to compete on the market for the next 25-
35years.
4.0 Shelf Life
4.1 Products should last 25-35 years
4.2 Products could be stored by distributors for up to twelve months.
5.0 Target Costs
5.1 The product should have an end-user cost of under £1200.
5.2 The cost of manufacture should be less than £500.
5.3 The cost of packaging and shipping should be no more than 10% of the
manufacturing cost.
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6.0 Quantity
6.1. Made to order
7.0 Maintenance
7.1 The final product is to be predominantly maintenance free, except for
periodic lubrication.
7.2 Any parts requiring lubrication should be easily accessible.
7.3 No special tools should be required for maintenance.
8.0 Marketing
8.1 Initially to be manufactured for the European market but increasing
globally within
12 – 18 months.
9.0 Packaging
9.1 Packaging and transport cost should be kept to a minimum, ideally below
6% of the unit cost.
10.0 Size and Weight Restrictions
10.1 Weight should not exceed 30 kg.
10.2 Stored height not to exceed 1200 mm.
11.0 Shipping
11.1 The final product will be shipped mainly by road within Europe however it
may be shipped by sea to future global markets.
12.0 Manufacturing Processes
12.1Main fibreglass moulds to be made by hand
12.2 Production capacity is available to produce 1,000 per year.
12.3 Where possible standard metric components and materials to be utilised
i.e. brake callipers, levers, housings.
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12.4 Castings and injection moulds for components produced by external
suppliers.
13.0 Aesthetics
13.1 The appearance is secondary to function.
13.2 Where possible the final appearance must promote confidence in the
function.
14.0 Ergonomics
14.1 All handles levers or controls to be easily accessed and should promote
product safety.
14.2 The design shall fit customer’s specifications.
14.3 The Folding Bicycle design must consider both Ergonomic and
Anthropometric information.
Both types of information are required to help the development of a Folding
Bicycle design, which shall fit in as naturally as possible with the user’s posture
and body movements.
15.0 Quality and Reliability
15.1 Quality should be such that products should not fail within a period of
three years and only 0 in 100 should fail within the first year.
16.0 Standards and Specifications
16.1 All components should adhere to the appropriate British and European
standards: e.g. BS EN ISO 4759-1 — Tolerances for fasteners. Bolts, screws,
studs and nuts.
17.0 Safety
17.1 Product stability is critically important during use.
17.2 The final solution should promote product safety and ease of use.
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18.0 Testing
18.1 Testing is to be carried out on 12% of units.
18.2 The prototype shall be tested under full load while being manoeuvred
over varying surfaces which replicate as far as possible the normal working
environment that the bike is required to perform in. This shall be carried out for
a pre-determined number of hours.
19.0 Disposal
19.1 Plastic parts should be marked to aid disposal.
19.2 All metallic parts should be 100% recyclable
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Identify a problem/ Commuting with a bicycle
Commuting by bicycle has always been a problem, unless you are travelling
the whole journey by bike it has to be carried on to a bus, train or car. The
solution to this is a folding bicycle that can be transformed from a road legal
bicycle to carryon piece of luggage with as little effort as possible.
The aim of this project is to produce a prototype that has all the qualities of a
rigid framed bike that can be folded down into a lightweight carryon piece
of luggage.
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Research Strategy
1. Mitchell Library
Electric Bicycles: A Guide to Design and Use (IEEE Press Series on Electronics
Technology) by William C. Morchin and Henry Oman
Bicycle Design: The Search for the Perfect Machine by Michael Burrows and
Tony Hadland
Bicycle Design by Mike Burrows
2. Dales Cycles
Check new bicycles and components that are available to see them first
hand and to look for ideas for concepts.
3. Internet
17 Bicycle (Japan) A-Bike (UK) Abio (USA/Canada) AezdaFoldingBicycles (Canada) Aiolos (Germany) Airframe (UK) Airnimal (UK) Aleoca (Singapore) Amiiva (France) Amxma (Taiwan) A.S. Bikes (UK) Asahi (Taiwan) Asama (Taiwan) Asia Bicycle Trading Company (Taiwan) Atala (Italy) Batavus (Netherlands) Bazooka (Canada) Be.Bike (Japan) Beixo (Netherlands) Belize Bicycle (Canada) Bernds (Germany) Bigfish (Slovenia) Bike-in-a-Bag (UK) Bike Friday (USA) Biomega (Denmark) Birdy (Germany) Blanc Marine (France) Breezer (USA) Bridgestone (Japan) Brompton (UK) Changebike (Taiwan) Checker Pig (Germany) Citizen Bike (USA) Clou (Austria) Dahon (USA) Daudbikes (UK) Dawes (UK) Dibar (Taiwan) Di Blasi(Italy) Doppelganger (Japan) Downtube (USA) Dynamic Bicycles (USA) Figmo (Taiwan) Flamingo(GraceGallant)(Taiwan) Fonta Cycles (Ireland) Fubi (Finland) Gazelle (Netherlands)
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Gianetti Bikes (Italy) Giant (Taiwan) Giatex (Taiwan) Gitane (France) GoBike (Canada) Goericke (Germany) Goods-2-Go (Lite Ride) (Canada) Hasa Bike (Taiwan) Hercules (Germany) Hidesawa (Taiwan) High Minded Bicycle (China) Hodaka (Japan) Ignio (Japan) Iko (Germany) Italwin (Italy) Ixi (USA) Jango (Taiwan) Jee Ann (Taiwan) Kenhill (Germany) KHS (USA) Kinn-Ovations (USA) Koga Miyata (Netherlands) Komda (China) Kuwahara (Japan) Land Walker (Japan) Lapierre (France) Liyang (Taiwan) Lordan (Argentina) LucaBike (USA) Maderna Cycle Systems (Austria) Melon Bicycles (USA) Mezzo (UK) Ming Cycle (Taiwan) Mobiky (France) Montague (USA) Monty (Spain) Moulton Bicycle Company (UK) Murayama (Japan) Neobike (Taiwan) Ningxing Bicycle Company (China) Onipax (Taiwan) Onyerbike (Australia) Orbita (Portugal) Ori (Taiwan) Oyama (Taiwan) Pacific Cycles (Taiwan) Pacy (Germany) Panasonic (Japan) Panther (Germany) Pashley-Moulton (UK) Peerless Bicycles (China) Peregrine Bicycle Works (USA)Peugeot (France)PhoenixBicycle(China) Pinnacle Bikes (UK) Polygon (Indonesia) Power Kat (Taiwan) Pro Walker (Taiwan) Puma (Germany) Q-Bike (Taiwan) Quix (Germany) Rabbit Cycles (Germany) Raleigh (UK) Ridgeback Bikes (UK) Rodados Aurora (Argentina) Samchuly Bicycle (South Korea) San Eagle (China) Santosa (Taiwan) Saracen (UK) Schwinn (USA) SEC (Taiwan) Senan (China) Sette (USA) Shunde Qile (China) Sliding Bike Development (Taiwan) Slingshot (USA) Smartcog (Japan) Speed one Bike (Taiwan) SRS Bike (Taiwan) Strida (UK) Sun Bicycles (USA) Swift (USA) Tianjin Flying Pigeon (China) Tsan Ching Limited (Hong Kong) TW-Bents (Taiwan) Ubike (Taiwan) Utopia Velo (Germany) Vela.ca (Canada) Winora (Germany) Worksman Cycles (USA) Xootr (USA) Zed Cycles (UK) Zero Cycles (UK) Zerobike (Spain)
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4. Cycling Magazines
http://www.bikeradar.com/road/
http://www.bikemag.com/
http://www.bicycledoctor.co.uk/links_magazines.html
http://www.cyclingweekly.co.uk/
http://bicycledesign.net/page/28/
http://www.cycloc.com/cycloc-awards.html
http://www.vehiclemagz.com/3-best-cruiser-bicycle-design-for-city-
users/2011/04/
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Product Research & current technology
The folding bicycle market is a very large one that is increasing all the time.
People not only use them for convenience in their daily commuting to get to
and from work saving them the cost of fuel, parking and the stress of rush
hour traffic. People are becoming increasingly more environmentally
conscious therefore commuting by bicycle and not travelling in a car their
carbon foot print is extremely reduced and their personal health benefits
from cycling.
Brompton
The best known folding bicycle manufacturer is Brompton who have been
producing the folding bicycle since its inventor Andrew Richie patented it in
1975. Its design is quite simple using hinge joint and screwed clamps to hold
together the high tensile steel frame. The bicycle consists of three folding
joints when unfolding the Brompton as shown below. The final folded
package is 565×545×250 millimetres (22.2×21.5×9.8 in) and weighs between
9–12.5 kg (20–28 lb) depending on the configuration. The cheapest
Brompton’s start at £595.00 up to over £1000 so making it an unattainable
asset for the majority of commuting public.
http://www.brompton.co.uk/page.asp?p=3059:12/3/2011
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There are many other manufacturers of folding bicycles on the market that
look more modern and up to date; they have new features like disk brakes
and hidden cables. Many other different ways of folding a bike have been
thought up but with more engineering comes more problems. But aluminium
alloys and aluminium-matrix composites, titanium and magnesium alloys, and
carbon fibre composites now all compete with steel.
Dahon Curve D3
The world's biggest folding bike company is Dahon. Dr David Hon produce his
first folding bicycle in 1982 the design is very similar to the Brampton with the
low crossbar and high seat and handlebar posts. The aluminum frame`s are
made from custom drawn and double-butted Sonus 7005 aluminum tubing
which is an aerospace grade aluminum that is 5-10% stronger than 6061
aluminum by most measures. The steel frames are made from seamless 4130-
chromoly steel that has been work-hardened in a special machining process.
The head tubes are CNC machined, the frames are TIG welded out of the
materials, like 4130-chromoly and double-butted 7005 aluminum alloy, all
Dahon bikes feature a second safety lock on every folding mechanism
providing an extra periphery of safety the price of a Dahon start at under
£300
http://www.dahon.com/12/3/2011
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Identify the best materials suited to bicycle the design
STEEL
As the most widely used material Steel constitutes for 95% of the worlds
bicycle manufacture the reason for this is simply because it is cheap, and the
stiffest, strongest and hardest structural material available. Different grades
of steel have different properties this being said all grades of steel have the
same measurement of stiffness which is called the Modulus of Elasticity. To
process the steel into a frame it is rolled from a steel strip then electro welded
into a tube ready for the construction of the frame by lugged brazing the
pieces of tube together.
Mike Burrows: BICYCLE DESIGN 2008 p.62
LUGGED BRAZING
Brazing is the joining of two pieces of metal with sockets called lugs with a
molten filler metal; this is probably the most versatile of the joining methods.
The temperatures used in the brazing process are comparatively low; the
Method itself is quite economical and quick. Frequently the joints are found
to be stronger than the metal that is being joined as they have a great tensile
Strength. The metals being joined are not themselves heated therefore
retaining their original metallurgical characteristics.
Mike Burrows: BICYCLE DESIGN 2008 p.65
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ALUMINIUM
All structural aluminium is alloyed with a small percentage of other elements
and designated into groups that have comparable main additives. The
groups run in progression from the 1000 series which is pure, to the 8000 series
that has lithium as the main supplement. Aluminium tubes use larger
diameters and multiple shapes like ovoid, triangular, box, etc. This is to
increase strength ratios. Aluminium is more corrosion-resistant than steel.
6061
Aluminium 6061 is silicone and magnesium based, it is the most common
grade used in bicycle building, quite strong, has good corrosion resistance
and welds well. To avoid cracking it subsequently requires specialised heat
treatment afterwards, this is accomplished by heating the whole frame at a
temperature of 450° for one hour, quenching in cold water to fully anneal the
welds, then reheating to 140°C for 30 minutes to gain a grade known as T6.
7005 and 7020
This grade is favoured with mass producers as 7005 and 7020 is a stronger
material than 6061. They have similar corrosion resistance and formability but
6061 has inferior welding characteristics. It doesn’t lose as much strength as
6061 but even if heat treated it can never return to full strength, this is (stress
corrosion) the cracking that occurs with regular flexing that any frame will
Encounter together with galvanic corrosion between the limitations of the
welds.
Mike Burrows: BICYCLE DESIGN 2008 p.67/68/69
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TITANIUM
With no loss of strength after welding and half the weight of steel but with a
modulus and tensile strength parallel to steel, titanium is favoured by bicycle
designers and builders. There is a drawback with titanium as it is only
available in a limited number of sizes, there is a lack of butted tubing, this is
due to the production of it being made for the aerospace industry, for
hydraulic pipes. With no loss of strength after welding
Mike Burrows: BICYCLE DESIGN 2008 p.71/72
CARBON FIBRE
A diamond is a very strong and hard substance. This is a direct result of its
microscopic structure, which comprises of each individual carbon atom
Being covalently bound to 4 other carbon atoms. Carbon is without doubt
one of the most versatile elements known to man, as can be seen by the fact
that it is the basis of life on this planet. Carbon forms the basic building block
of virtually all organic chemistry Almost all carbon fiber is made from a
common industrial fiber called polyacrylanitrile fiber, also known as
PAN. Most PAN fiber is used to make acrylic fiber. It is also used to make
carbon
Fiber with a pyrolizing process, which means it, is heated to ultra high
temperatures to remove all elements except the carbon. Most carbon fiber
is sold at this point and it has a tensile modulus of 33 million pounds per
square inch.
Mike Burrows: BICYCLE DESIGN 2008 p.73/74
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Components needed in a bicycle/ Bicycle Standards
Bicycle Standards
Listed below are the parts covered by different Standards:
Handle Bars BS 6102-1
Brakes BS 6102-1
Front Light BS 6102-3
Chain BS 6102-1
Fork BS 6102-1
Tubes/Tyres BS 6102-5
Pedals BS 6102-1
Saddle BS 6102-1
Rear Light BS 6102-3
Chain Guard BS 6102-1
Brake blocks BS 6102-16
Frame BS 6102-1
Wheels BS 6102-6
There are many parts of the Standard covering bikes and accessories. The full
title of the main part is BS 6102-1 Cycle. Specification for bicycles safety
requirements. It's referred to in UK legislation, and manufacturers have to
build bicycles to this Standard to ensure that they are safe and durable.
Different parts of the Standard are shown on the diagram and are used by
The manufacturers to ensure test methods, specifications and dimensions are
followed accurately.
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http://www.bsieducation.org/Education/14-19/topic-areas/bicycles/bicycle-
spec.shtml:18/03/2011
Folding Mechanism
A mechanism for folding a bicycle, comprising an upper grip of a U shaped
trough-like construction having a handle with a pulling eye on a top portion
thereof, a hole provided at a bottom of said upper grip, two side wall each
having an elliptic hole opened through a middle portion thereof, and a hook
with a mouth provided in front of each of said elliptic holes;
A lower grip of a U shaped construction having two sides, wherein each of
said sides has an upper through hole provided at an upper portion thereof
and a lower through hole provided at a lower portion thereof, said upper
and lower grips being linked together by means of a connecting pin which is
passed through one of said elliptic holes, via said two upper through holes
and coming out of said another elliptic hole, such that said upper grip is able
to turn around on said lower grip; an upper tube base of a funnel-like
structure comprising a circular adapter which has a hanger mounting on a
surface thereof, a depressed surface provided in a front part of said circular
adapter, a holder provided in a front part of said depressed surface, two
positioning holes respectively provided on a right and a left side of a rear part
of said circular adapter, and a contact rim formed at a bottom periphery of
said circular adapter;
A lower tube base comprising a base disc attached thereto, wherein said
base disc has a ring groove surrounding along an inner part thereof, two
inserting holes provided in a front part thereof, and two fixing holes provided
in a rear part thereof, wherein a fixing rod is inserted through one of said two
fixing holes of said base disc, said two positioning holes of said circular
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adapter, and then said another fixing hole of said base disc so as to enable
relative motion of said circular adapter with respect of said base disc,
wherein a supporting rod is inserted through one of said two lower through
holes of said lower grip, said two inserting holes of said base disc, and then
said another lower through hole of said lower grip so as to enable mutual
latching between said lower and upper grips; and an adjustable set pin
which is a screw rod with threads screwing to a thread hole provided on said
connecting pin, said adjustable set pin having a fixing end at an end terminal
thereof, wherein said fixing end of said adjustable set pin penetrates through
a spring and said hole of said upper grip, therefore an extending length of
said adjustable set pin out of said hole is adjustable by turning said adjustable
set pin, depending on a relative motion between said Threads of said
adjustable set pin and said thread hole of said connecting pin; when folding,
letting said contact rim of said circular adapter coupled to said ring groove
and said fixing end of said adjustable set pin in contact with said upper grip
upwards with a finger inserting into said pulling eye and bringing said hook on
said upper grip towards said hanger provided on said upper tube base, at
this moment said spring being in compressed state, after said hook having
reached position above said hanger and said finger being released from said
pulling eye, said spring restoring a normal state thereof And said hook
engaging tightly with said hanger and latching both said upper and lower
tube bases.
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This is the folding mechanism from a Brompton
Tightening lever Fixing Clamp
The hinge has a simple joint
On crossbar
The same joint is used on the handlebar
Post.
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This is the rear joint with the shock
absorber that folds round and
under the crank.
The rear carrier has small wheels for when the bike is folded for easier mobility
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Cycling Biomechanics
Biometrics is the science of how the body powers the bicycle by the external
force’s the cyclist uses in opposition to the bicycle. Essentially the cyclist is the
engine so it is important that the power is introduced with optimal and
efficient delivery. Positioning is essential not only for comfort and maximum
performance but to decrease the chance of injury to the rider therefore all
variables related with ride position and equipment set up are essential.
Saddle height alters variables of muscle length, joint angles and the energy
output that the muscles force down to drive the bicycle. Increased saddle
height equals greater ease of pedalling; this is directly related to the length of
the crank. The crank length when increased will enhance torque when
decreased it adds to muscular tension this is remedied by the saddle being
adjusted relative to the crank length to compensate either way. The
recommended standard for cyclists is to select an angle where the kneecap
of the leading leg is directly over the pedal axle when the cranks are
horizontal.
http://www.cyclinganalysis.com/annotated-bibliography-cycling-
research/general-reviews-biomechanics-cycling
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Ergonomics
Ergonomics also known as the Human Factor which is the science of
understanding the human interaction with equipment, environment, systems
and products, it draws on human biology, psychology, design and
engineering. It’s intended to expand and relate knowledge and techniques
to optimise system performance whilst still protecting the health and safety of
the persons concerned.
The ergonomics of a bicycle consists of seating position to the pedals and the
handlebars there are many different kinds of seats and handle grips that are
designed for the ease and comfort of the user.
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Practicality
The folding bicycle is a genius gadget for commuters to travel to and from
their work place with the ease of transition from cyclist to passenger. It has
the practical solution to storing it by its ability to fold meaning there is no
need for a padlock or chain as it can quite easily be kept under a work desk
or in a cupboard, it also making it possible for someone who may not be able
to have a bicycle for recreational use due to storage in their home if it is only
a small dwelling.
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Pro Forma
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Milestones
End of Planning 25/3/2011-12:15pm
End of Development & Testing 13/5/2011- 12:15pm
End of Evaluation 27/5/2011- 12:15pm
Materials and resources required for the development of project
Microsoft word:- home access, college
Microsoft excel- home access, college
Microsoft PowerPoint- home access, college
Microsoft Project- home access, college
Autodesk: Inventor- home access, college
o :3D max- home access, college
o : CAD workstation- home access, college
Printing Facilities- home access, college
3D printing facilities college
Drawing facilities home access, college
Modelling equipment home access, college
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Library college, Mitchell
Internet home access, college
Physical research Dales cycles,
Deliverables with each of these milestones:
Milestone Deliverables
End of Planning All relevant research, standards, materials
End of Development Materials, CAD drawings and prototype
End of Evaluation Prototypes for testing
Materials tested and ready for construction
Fabrication complete
All assembled parts tested & inspected
Date:
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DEVELOPMENT
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Concepts
Concept A
Concept A is a recumbent bicycle design with 3
hubbless wheels, two angled rear wheels for stability
and a direct drive crank on the front wheel with a
ratchet bearing for coasting. The two rear wheels are
attached to the frame by a pivot which allows the
bicycle to be steered via the rear wheels. The frame
is carbon fibre to help with keeping the weight down.
Concept B
Concept B is an A frame bicycle with hubbless
wheels with the rear being driven by a rubber
belt and crank. This design folds in two places
making it even more compact, it has an
ergonomic saddle and crank for the riders
ease and comfort
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Concept C
Concept C is a racing frame bicycle
with hubbless wheels with the rear
wheel being driven by a belt. This
bicycle has a higher ridding position.
The frame consists of three parts, the
crossbar which connects from the
saddle to the steering, the front steering
and wheel and the lower part of the frame with the crank and rear wheel.
Concept D
Concept D is a recumbent bicycle with hubbless
wheels being driven directly from the front with a
ratchet bearing on the crank so the bicycle can
freewheel. The frame has a carbon fibre casing,
ergonomic seat and handle grips it also has a built
in front and rear light.
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Concept Evaluation
Concepts are rated from 1-5.
Concept A and D have the highest rating and the two designs are
recumbent, parts of each can be integrated with each other making a more
aesthetically pleasing design.
CONCEPT SAFETY DESIGN MAINTANANCE COST RESULT
CONCEPT A 4 4 4 3 192
CONCEPT B 3 3 4 3 108
CONCEPT C 4 3 4 3 144
CONCEPT D 4 4 4 3 192
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Modelling
The crank was modelled by extruding a circle then to
model the teeth for the cog an ellipse was extruded
and subtracted from the circles edge. The crank legs
were an extruded circle that was revolved 90 degrees
then lofted to the required size and diameter. Finally
the hole and thread tool so the pedal could be fitted.
The wheel was an extruded circle with a square hole
that was circular patterned for the crank to fit.
The front of the frame was modelled by drawing
the outer shape with arcs to the size that was
needed then extruding the shape to the required
size. Once extruded the model was shelled
leaving a thickness of 3mm making sure the wheel
and tyre had enough clearance to rotate freely.
The end was lofted 30mm to oval shape of the
frame tubing.
The tubing was an oval that was swept
along a path of the frames shape for either
side of the folding part of the bicycle, they
are exactly the same shape so when folded
they sit neatly together.
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The rear steering housing is two
revolved ellipses that sit at an angle
to hold the rear wheels in place. It
is fixed in place with a pin from the
rear part of the frame with bearings
on connecting part.
The seat was a revolved arc as was the
backrest, the handle grips were made with a
series of arcs being lofted to the correct shape
required then the hole tool was used so they
would fit on the handlebars.
The brake callipers were
drawn to the correct
shape and size then
extruded with a circle for
the brake blocks to be
fitted to by threading a
hole the same diameter
as the brake blocks.
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Recumbent Frame
Carbon fibre is now considered one of the ultimate materials to construct
high-quality bicycle frames from. It is lighter than Aluminium, stronger than
steel and when properly laid-up, has the stiffness desired in a performance
bicycle. Carbon fibres are just like rope and present their greatest strength
when under tension. To work properly, carbon fibre must be arranged in a
configuration and series so that loads run along its length; it has numerous
different grades based on the material’s strength. The “modulus” —used in
most bicycles use intermediate grades. The greater the modulus the better,
as the modulus increases the fibres gain tensile strength, but can also be
more difficult to work with. A foam mould of the frame is made and the
carbon fibre applied and bonded until cured cast aluminium lugs are
bonded to the frame to let bearings be fitted where they are needed for the
crank and steering.
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EVALUATION
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Evaluation
In the planning stage of this project I started with researching all different
types of bicycle design and materials. For this part of the project I feel that
my research was probably my strongest point as I found all of information
that that is required to properly build a road legal folding bicycle, allot of
concepts from design forums that gave me fresh ideas for my model.
The development stage of the project was my weakest part, firstly when
sketching my concept I took far too long as I kept changing each sketch
instead of sticking to each idea and moving on. This had a knock on effect
to the rest of the project as when I started my 3D CAD model time was
running out and some of the parts for my model were quite complex so to try
and keep on schedule I had to sacrifice them for more basic parts that took
less time to model. Having to do this didn’t affect much more than the
aesthetics of the final model as the majority of my objectives were met to my
project brief.
On completion of this project the skills I have gained are knowing where to
look for the correct information relating to the task ahead and how deep to
research thing without getting distracted from the important thing by going in
a different direction than is required for the task at hand, once a plan has
been set to try to stick to it. I am quite happy with the end result of my work
but feel I let myself down as I know I could do allot better.
If I were to undertake a similar project I would stick to the project schedule
meticulously, once I had my concepts in place they would not be altered
and when I started my modelling they would be as they were in my concept
sketches and not being modified as I was modelling them.
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Bibliography
14 http://www.brompton.co.uk/page.asp?p=3059:12/3/2011
15 http://www.dahon.com/12/3/2011
16 Mike Burrows: BICYCLE DESIGN 2008 p.62
Mike Burrows: BICYCLE DESIGN 2008 p.65
17 Mike Burrows: BICYCLE DESIGN 2008 p.67/68/69
18 Mike Burrows: BICYCLE DESIGN 2008 p.71/72
Mike Burrows: BICYCLE DESIGN 2008 p.73/74
19http://www.bsieducation.org/Education/14-19/topiareas/bicycles/bicycle-
spec.shtml:18/03/2011
24http://www.cyclinganalysis.com/annotated-bibliography-cycling-
research/general-reviews-biomechanics-cycling
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Drawing sets
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