Taylor AmarelME 134 Section 6Prof. Porumamilla

November 28th, 2012

Partner:Kaitlin Thomas

Introduction:

The purpose of this experiment is to research and design an innovative bike that serves a dual purpose of a reclining chair and an off road bike. The purpose of this invention is to provide users the ability to work or relax off the beaten track for an entire day while minimizing the amount 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 final product would be the most cost effective, quality product possible.

Analysis:

Several designs were considered in order to best accomplish our goal. After preliminary review three designs were chosen for further analysis. Design 1 (See Appendix A), reference here after as The 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 easiest and most cost effective modifications while excelling in ease of use, safety, and bicycle functionality. Concept Frame Design proved to be too complicated to manufacture and far too costly to produce. Suspended Seat Design would have had significantly reduced bicycle functionality and the modifications were still not as practical as The Final Design.

Results:

Criteria Concept Frame Design

Final Design Suspended Seat Design

Cost 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.

Table 2. A cost break down of components and labor for the Concept Frame Design.

Table 3. A cost break down of components and labor for the Final Design.

Table 4. A cost break down of components and labor for the Suspended Seat Design.

Part Cost in DollarsCustom 3D Printed Frame 10000Custom 3D Printed Handle Bars

2000

Standard Chain and Sprockets 100Standard Shifters and Derailleur 100Disk Brakes 75Standard Wheels 100Standard Cables 10Chair Cloth 500Custom Mounting Hardware 200Assembly expense 1000Total Cost 14085

Part Cost in DollarsSpecialized Mountain Bike Frame 200Specialized Handle Bars 30Standard Chain and Sprockets 50Standard Shifters and Derailleur 35V Brakes 30Standard Wheels 100Standard Cables 10Custom Semi-Rigid Cloth 100Extra member, mounting hardware, and cloth holder 300Assembly expense 200Total Cost 1055

Part Cost in DollarsSpecialized Mountain Bike Frame 2000Specialized Handle Bars 50Standard Chain and Sprockets 50Standard Shifters and Derailleur 35V Brakes 30Standard Wheels 100Standard Cables 10Custom made cloth 75Mounting hardware 30Assembly expense 300Total Cost 2680

Discussion:

The three different designs all provide the ability to work or relax off road while still being a functional mountain bike. The Final design provides a hammock by suspending a cloth between the front fork and an extended frame member (See Appendix A). The Concept Frame design provides and chair like platform by splitting in half and suspending cloth between the two frame halves (See Appendix B). The Suspended Seat Design provides a hanging seat by suspending a semi-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 2,3 and 4 the Final Design was the least expensive. Notably, The Concept Frame Design was not chosen because of the relatively high cost to manufacture. Table 2 shows that the 3D printing of a custom composite bike frame and assembly would cost over $10,000 alone. While the Final Design scored well in various design criteria displayed in Table 1, the improvements did not warrant the increase in cost. The Suspended Seat Design had a more reasonable cost but compared to the Final Design the additional cost did not provide any significant benefit as can be seen in Table 1. Furthermore, The Suspended Seat Design scored low in safety due to relative instability of the seat compared to the other designs. Overall the final design had the highest cumulative 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 Final Design is an off the shelf prefabricated specialized mountain bike frame. The use of prefabricated parts greatly reduces the cost of manufacturing. Furthermore, the use of an unmodified frame inherently increases safety as compared to the Suspended Seat Design which would 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 water bottle like case. The Final Design also makes use of components in multiple ways; the seat for the bike is also used as a hammock hanger and head rest. By using parts in multiple ways both the cost of parts and labor will be decreased for production. The Final Design may be folded by removing the front tire, handlebars, and seat; by removing these parts the bike would be able to fit inside the trunk of a mid-sized sedan. By utilizing quick release screws it is unnecessary to use any tools for assembly, reconfiguration, and disassembly. Quick release screws are commonly used on front bike tires and are hand tightened.

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