Tricycle Frame
Redesign
Team Members:
Fiona Hughes, Gina Policelli, and
Jodie Wu
Overall Goals
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Problems
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Current frame design is too weak to support necessary weight and
retain functionality in the given conditions
Current frames are “one size fits all” (not adjustable for user)
Current tricycles are too large to be used indoors or on public
transportation
Difficult to make the frame
Goals
To improve on the design of the
tricycle frames so that they are
better suited and more
convenient for the user
Increase…easier and cheaper
to build and repair
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http://web.mit.edu/sp.784/www/projects.html
Functional Requirements
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Strength: The trike frame should be strong enough to support the
rider and some cargo.
Robustness: The trike should be robust, appropriate for the
conditions it will be used in.
Easily Built and Repaired: It should be easy to make and repair,
and the shops should be able to produce it with the tools they
already have.
Manufacturable: The trike frame should be made from parts that
are cheap and readily available.
Adjustable: The trike should be able to accomodate people of
different ages, disabilities, and sizes. It should be easy to get in and
out of.
Lightweight: The trike frame should be light and compact.
Low Cost: It should be affordable to produce and to buy.
Design Strategy:
Symmetric Frame
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Current Frame: Asymmetric
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Proposed Strategy:
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slows down the production process
difficult to repair
Inaccuracies in bending  takes time to adjust, inefficient
Create a design in which the right and left sides of the tricycle
are identical
The new frame will be built with a single jig
Develop a design that increases the strength and stability of
current tricycle
Advantages:
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Increase production rate
New frame easier to repair
Eliminates the need to adjust jig for each side
Establishes uniformity and improves quality
Design Strategy:
Use of Bike Frame
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Current Frame: Built from scratch
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Proposed Strategy:
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All bending and welding is done by trike manufacturer
Only stock steel is used
Investigate the use of bike frame and integrating these parts into
the overall design of the tricycle frame
Look into the unconventional use of common, readily accessible
products (threaded pipe fittings, etc.)
Advantages:
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Less welding
Less bending
Minimization of cost and manufacture time
Easy to build
http://www.askadavid.org/photos/photos6
Increases accuracy of manufacturing
9/bicycle_with_tomatoes.jpg
Design Strategy:
Adjustable
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Current Frame: “one size fits all”
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Proposed Strategy:
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Frame is not adjustable
Does not cater to different people’s needs (different sizes, ages,
and disabilities)
Adjust height of seat
Adjust distance from seat to hand crank
Create removable storage space/bin
Make a design that is scaleable to the user
Advantages:
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More suitable and useful for different types of people
More functional and versatile for the user
Evaluation of Strategies
Parameters
Symmetric Bike Frame Adjustable
Strength x 2
Robustness x 2
+
+
+
0
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Repairable
Manufacturable
+
+
+
0
-
Adjustability x 3
-
-
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Low Cost
0
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-
Total
+3
0
+1
Chosen Strategy
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Symmetric and Adjustable Frame
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Symmetric: If the symmetric frame cannot be
made, we will investigate how to make it easier to
build while increasing strength.
Adjustable: If we cannot make the frame
adjustable, we will at least make it scaleable for
different users.
In order to accomplish this, we will work
closely with the community partners and
explore the possibilities.