Folding Bicycle 1

FOLDING BICYCLE

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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FOLDING BICYCLE

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 There are a few historical references to so-called folding bikes but the descriptions of them sound more like "disassemble-able" bikes rather than true folders wherein the frame actually collapses,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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FOLDING BICYCLE

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 2535years. 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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FOLDING BICYCLE 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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FOLDING BICYCLE 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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FOLDING BICYCLE

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-cityusers/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 4130chromoly 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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FOLDING BICYCLE http://www.bsieducation.org/Education/14-19/topic-areas/bicycles/bicyclespec.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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FOLDING BICYCLE 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-cyclingresearch/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

FOLDING BICYCLE

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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FOLDING BICYCLE 

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

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

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.

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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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FOLDING BICYCLE 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/bicyclespec.shtml:18/03/2011 24http://www.cyclinganalysis.com/annotated-bibliography-cyclingresearch/general-reviews-biomechanics-cycling

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Drawing sets

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