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Abstract

The stretcher is a devise used to carry beach grass. It was created for use by the Friends of the Dunes by the Humboldt State University Engineering 215 class. The stretcher will be used by volunteers at the Humboldt Coastal Nature Center.

Background

The goal of the Friends of the Dunes is to conserve the natural diversity of coastal environments. One thing they do to obtain that goal is remove the invasive beach grass from the dunes in Arcata, CA. The Stretcher was designed to transport the beach grass at the Humboldt Coastal Nature Center from the dunes where it is being removed, to awaiting vehicles that will haul the beach grass offsite. The stretcher can be carried by two or more people, or the separate wheel and axel can be attached for use by one person.

Problem Statement and Criteria

Problem Statement The objective of The Stretcher is to supply a means to carry beach grass from the dunes where it is being removed to loading vehicles by the Nature Center’s volunteers. The volunteers need to be able to carry large amounts of grass a short distance either with two people carrying the load, or a single person.

Criteria The criteria were distinguished by our group in coordinance with the client in order to weigh different aspects of our alternative solutions to come up with the best solution possible.

Criteria Description Weight
Dune Impact Minimize impact on the dunes 6
Safety How safe the user is 8
Cost How much it costs to make and maintain the product 4
Ease of Use How easy the product is for the user 7
Durability How durable the product is 5
Maneuverability How maneuverable the product is 8
Environmental Appropriateness How environmentally appropriate the materials are 4

Design Description

The stretchbarow design consists of a stretcher with long, wooden handles that can be carried by two or four people. These handles can also be attached to a separate axel with two wheels so that it can be used as a wheelbarrow as well for more convenient use by a single person.

The Stetcher

The stretcher is made of four pieces of oak 2 x 2’s, making a rectangle. A drop cloth is attached to the center of the rectangle to create an area for the beach grass. The dowels are held together by screws, and the drop cloth is attached to the wooden frame by screws as well. The cloth drops down in the middle by about a foot to create more area for the grass so that it will not fall off the sides of the stretcher.

Wheels and Axle

Two wheelbarrow wheels are attached to a metal axle to be added to the stretcher for use as a wheelbarrow. The wheels are six inches apart to spread out the load of the weight so that it will be easier to use on sand.

Axle Attachment

On one end of the stretcher, both handles have curved brackets on the bottom side for the ends of the metal axle to slide into. These are placed six inches in from the ends of the handles.

Attachment and Removal Instructions

To put the axle onto the stretcher, one end of the axle can be put into the bracket on one of the handles, slid back as far as possible, and then the other end of the axle can be placed into the bracket on the other handle. The pins are then placed into the holes on each end of the axle outside of the handles to prevent any sliding or shifting of the axle.

To remove the wheels and axle, remove the pins from the axle and push it all the way to one side. Take out one end, and then pull it the opposite way to completely remove it.

Costs

Design Time Input

The design cost accounts for the total time the group spent on the project outside of class. The combined times sum up to about 200 hours, most of which can be attributed to Phase 5 of the design process. The figure below shows the distribution of hours allocated to each phase.

Design cost stretchbarrow.jpg


Cost of Materials

The materials cost consists of the total cost of materials needed to create the project. The total amount was ___ as displayed in the table below. A few of the materials were donated, so a projections cost was added for reference.

Results

The results of our testing out at the dunes

Constuction Process Steps

Instructions how to build the design and keys on replicating it.

File:Bpack bike trailer - demo 1.jpg
How construct the "Stretchbarrow"

Discussion and breakdown

References

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