FOLDING BICYCLE

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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 There are a few historical references to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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