Taylor Amarel ME 134 Section 6 Prof. PorumamillaNovember 28th, 2012 Partner: Kaitlin Thomas
Introduction:The purpose of this experiment is to research and design an innovative bike that serves a dualpurpose of a reclining chair and an off road bike. The purpose of this invention is to provideusers the ability to work or relax off the beaten track for an entire day while minimizing theamount of supplies needed.Our design was influenced by the research done with regards to cost of production, ease of use,safety, and bicycle functionality. These considerations were made priorities so that the finalproduct would be the most cost effective, quality product possible.
Analysis:Several designs were considered in order to best accomplish our goal. After preliminary reviewthree designs were chosen for further analysis.Design 1 (See Appendix A),reference here after asThe Final Design. Design 2 (See Appendix B), reference here after as Concept Frame Design.Design 3 (See Appendix C), reference here after as Suspended Seat Design.The Final Design was determined to be the best of the three designs. This design has the easiestand most cost effective modifications while excelling in ease of use, safety, and bicyclefunctionality.Concept Frame Design proved to be too complicated to manufacture and far toocostly to produce. Suspended Seat Design would have had significantly reduced bicyclefunctionality and the modifications were still not as practical as The Final Design.
Results:Criteria Concept Frame Final Design Suspended Seat Design DesignCost 1 7 8Functionality 7 7 3Aesthetics 6 10 4Safety 8 9 4Ease of Use 6 9 3Special Requirements 8 8 7Conversion Time 5 7 4 Table 1. A qualitative table of bike characteristic ratings with 10 being the best and 0 being the worst, these are estimates based on design and inherent advantages or disadvantages. Part Cost in Dollars Custom 3D Printed Frame 10000 Custom 3D Printed Handle Bars 2000 Standard Chain and Sprockets 100 Standard Shifters and Derailleur 100 Disk Brakes 75 Standard Wheels 100 Standard Cables 10 Chair Cloth 500 Custom Mounting Hardware 200 Assembly expense 1000 Total Cost 14085 Table 2.A cost break down of components and labor for the Concept Frame Design.
Part Cost in Dollars Specialized Mountain Bike Frame 200 Specialized Handle Bars 30 Standard Chain and Sprockets 50 Standard Shifters and Derailleur 35 V Brakes 30 Standard Wheels 100 Standard Cables 10 Custom Semi-Rigid Cloth 100 Extra member, mounting hardware, and cloth holder 300 Assembly expense 200 Total Cost 1055 Table 3.A cost break down of components and labor for the Final Design. Part Cost in Dollars Specialized Mountain Bike Frame 2000 Specialized Handle Bars 50 Standard Chain and Sprockets 50 Standard Shifters and Derailleur 35 V Brakes 30 Standard Wheels 100 Standard Cables 10 Custom made cloth 75 Mounting hardware 30 Assembly expense 300 Total Cost 2680Table 4.A cost break down of components and labor for the Suspended Seat Design.
Discussion:The three different designs all provide the ability to work or relax off road while still being afunctional mountain bike. The Final design provides a hammock by suspending a cloth betweenthe front fork and an extended frame member (See Appendix A). The Concept Frame designprovides and chair like platform by splitting in half and suspending cloth between the two framehalves (See Appendix B). The Suspended Seat Design provides a hanging seat by suspending asemi-rigid cloth between the front fork and pivoting frame member (See Appendix C).The Final Design was chosen for a number of reasons. For example, as can be seen in Tables 2,3and 4 the Final Design was the least expensive. Notably, The Concept Frame Design was notchosen because of the relatively high cost to manufacture. Table 2 shows that the 3D printing ofa custom composite bike frame and assembly would cost over $10,000 alone. While the FinalDesign scored well in various design criteria displayed in Table 1, the improvements did notwarrant the increase in cost. The Suspended Seat Design had a more reasonable cost butcompared to the Final Design the additional cost did not provide any significant benefit as can beseen in Table 1. Furthermore, The Suspended Seat Design scored low in safety due to relativeinstability of the seat compared to the other designs. Overall the final design had the highestcumulative score within the design criteria shown in Table 1.The Final Design was designed with many of the design criteria in mind. The frame for the FinalDesign is an off the shelf prefabricated specialized mountain bike frame. The use ofprefabricated parts greatly reduces the cost of manufacturing. Furthermore, the use of anunmodified frame inherently increases safety as compared to the Suspended Seat Design whichwould require modifying the frame. The Final Design uses the mountain bike frame and pre-tapped holes for mounting the additional frame member and hammock cloth contained in a waterbottle like case. The Final Design also makes use of components in multiple ways; the seat forthe bike is also used as a hammock hanger and head rest. By using parts in multiple ways boththe cost of parts and labor will be decreased for production. The Final Design may be folded byremoving the front tire, handlebars, and seat; by removing these parts the bike would be able tofit inside the trunk of a mid-sized sedan. By utilizing quick release screws it is unnecessary touse any tools for assembly, reconfiguration, and disassembly. Quick release screws arecommonly used on front bike tires and are hand tightened.
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