The Trailer Park Boys.

The amount of materials present in our waste stream grows everyday with only a fraction of these materials reclaimed through current recycling establishments. The objective of Cal Poly Humboldt and our group "The Trailer Park boys" in the Engineering 215 Introduction to Design class is to creatively upcycle materials in order to construct a bike trailer. The bicycle trailer will then be utilized by SCRAP Humboldt as an environmentally friendly alternative to collect and transport additional reusable materials back to Scrap Humboldt.

SCRAP Humboldt is a non-profit organization that strives to educate the local community about effective and imaginative reuse of waste materials through projects, as well as provide easy access to reclaimed materials. Being one of five creative reuse centers that are a part of the program SCRAP USA, SCRAP Humboldt opened their doors on April, 12, 2013 for the beginning of Humboldt County's first creative reuse center. The inventory for the store strictly runs on donations from the local community and is sold to customers for affordable prices.

Problem statement and criteria[edit | edit source]

SCRAP Humboldt needed a method of transporting donated items which would also serve as a functional example of effectively reusing upcycled material.

Criteria Weight Constraint
Safety 10 Must be visible at night, no sharp edges.
Usability 10 Easily and simplistically detachable.
Durability 9 Three year lifespan with appropriate maintenance
Useful Load 8 A minimum load capacity of one hundred pounds.
Size 8 The width cannot exceed thirty two inches, or the length cannot exceed 80 inches
Cost 7 Not to exceed three hundred dollars.
Environmental Justice 6 Greater than thirty five percent recovered materials by weight.
Aesthetics 5 More than four colors, and maintain a modular appearance.
Maintenance 5 Less than one hour of maintenance per 15 days of use.

Criteria and constrains are needed to determine the success of a solution. Criteria are weighted with 10 being most important and 0 being least important.

Description of final project[edit | edit source]

Here is a picture of the final design. It is about to be towed for testeing

This bike trailer is a fusion of repurposed goods. The trailer's intended purpose is to provide the capability to transport a minimum of 100 pounds of cargo from on location in Arcata, CA to the SCRAP Humboldt storefront where the donated goods can then be used for various projects or sold for personal project uses. The trailer was built from repurposed goods such as a wheelchair, electrical conduit, highway signs, and dry-suit material. The wheelchair frame is ideal for mounting the trailer's wheels because of the cantilevered hubs. This characteristic eliminates the axle that would stretch across the width of the trailer and potentially inhibit cargo space, as well as simplifying axle mounting. Electrical conduit was used for the rest of the frame because it has a high strength to weight ratio, is relatively easy to work with, is in abundant supply and is galvanized for weather resistance. A road sign was used to form the cargo bin because it has high reflectivity for safety, is lightweight, and is formed with relative ease. Due to the climate we live in, a cover to keep cargo dry was also incorporated into the design. The material for the cover was originally used for dry-suits and was donated to SCRAP Humboldt by Kokatat.

Costs[edit | edit source]

The cost analysis for the Upcycle Bicycle Trailer is split into design cost, implementation cost, and maintenance cost.

Design Cost[edit | edit source]

The Design Cost totals 387 hours. The pie chart displays the segregation by hours of each phase of the design process.

Implementation Cost[edit | edit source]

The following chart displays the cost of implementation separated into total retail costs and total cost for team Trailer Park Boys.
Item Quantity Retail price per item ($) Total Team price per item ($) Total
Wheel Chair 1 120.00 120.00 30.00 30.00
10' Galvanized E.M.T. 3/4" 10 11.00 110.00 0.00 0.00
10' Water Pipe 1 20.00 20.00 0.00 0.00
Road Sign 4'x5'x3/16" 1 28.50 28.50 28.50 28.50
Kokatat Cover 1 300.00 300.00 0.00 0.00
1/4" Bolts & Nuts 8 8.00 8.00 8.00 8.00
Pop Rivets 30 0.13 3.75 0.13 3.75
Heim Joint 1 15.00 15.00 15.00 15.00
Total Cost $605.25 $85.25

Maintenance Cost[edit | edit source]

The cost of maintenance analysis is restricted to the replacement of wearable parts and has been minimized through the simplistic nature of the design. The wheel bearings, tires, heim joint, and Kokatat cover are the primary components subject to continual wear through articulation, and will be the parts of interest. The wheel bearings and heim joints are commonly found at most general hardware stores and with adequate mechanical competence require no more than one hour of labor to replace collectively. The wheelchair tires, commonly found online, are of the "Snap On" design and could be both replaced with thirty minutes of labor. Chafing and tearing can be expected throughout the lifespan of the Kokatat cover and can be easily repaired using a Kokatat Field Repair Kit.

The following chart displays the cost of maintenance in frequency per year, hours per task, and total cost per operation per year.
Operating & Maintenace Frequency/Yr) Hrs Part Cost($)
Cleaning/Wiping Dirt 4 0.25 $5.00
Inspect and/or Replace Wheel Bearings 2 0.50 $20.00
Inspect and/or Replace Tires 1 0.50 $50.00
Repair Cover 1 0.50 $36.00
Inspect and/or Replace Heim Joint 1 0.25 $10.00
Total Cost 4.25hrs $121.00

Testing Results[edit | edit source]

We thought it would be a good idea to test our weight constraint as soon as we finished the project. Below are two pictures of the trailer (and Michael) being towed up and down a hill, and two pictures of the trailer displaying a visibility test during the night. The brake test was a success and the trailer itself didn't need brakes to bring the bicycle to a complete stop. It was also possible to tow the trailer with the 155 pound payload up hill. It may not be a pleasant or simple task to complete, but it is possible. The visibility test pictures speak for themselves. The unique element of the reflectivity that the road sign provides makes the trailer exceptionally visable.

Video[edit | edit source]


How to build[edit | edit source]

For a more in depth explanation on how to build a trailer similar to ours, here this link -> Instructions.

Discussion and next steps[edit | edit source]

There are minor concerns over the final design.

  • The hitch restricts the rider on right hand turns.
  • The cover and cloth lining could potentially mold due to Humboldt County's weather.

All minor concerns but thy should be taken into consideration.

Update October 2014[edit | edit source]

According to SCRAP Humboldt administration, since they have moved for a different location, not all projects are available on site. It was not possible to see and evaluate the bike trailer because, according to information from the SCRAP's staff, it is in the storage building since it is large. Also, according to the interview, the project is used during community events to show a creative and useful way of use upcycled materials.

References[edit | edit source]

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