ME 4182 Coneptual Designs Team: GT Rack 2:00 pm September 14, 2005

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ME 4182 Coneptual DesignsTeam GT Rack 200
pm September 14, 2005

• Ryan Glenn
• Andrew Mrasek
• Japheth Nelson
• Manuel McMillan
• Brian Collins
• Hyun Lee

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Objectives

• Present bounding parameters gathered from field
  research.
• Present and discuss conceptual design proposals.

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Bounding Parameters

• Garage heights are not standardized on campus.
• The height varies from 6 6 to 8 2
• Newer garages allow access for taller vehicles.

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Bounding Parameters

• A sample of vehicle heights for 33 common compact
  to mid-sized cars.
• A mean height of 56.99 and a median height of
  56.80 was recorded for the sample.
• SUVs and Minivans were not included in the
  sample due to the limitations imposed by garage
  height.
• For the project a garage height range between
  66 and 7 will be considered allowing a range
  of 21.01 to 27.01 above the vehicle.

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Conceptual Designs

• 5 Conceptual Designs
• Retrofit Bike Carrier design with ratcheting
  hinge
• Rotisserie Carrier using quick release pivot
  clamps
• Roller Assist with torsion spring collapsible
  arms
• Rear Sliding bike carrier
• Pneumatic shock assisted bike carrier

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Retrofit Concept
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Retrofit Concept

• Pros ()
• Utilize existing bike carriers on the market
• Relatively low design complexity
• Ratchet mechanism assists in the raising or
  lowering of the bike
• Cons (-)
• Questionable pedal and handle bar clearance when
  lowered
• Support systems on existing carriers may not
  properly support the load of a bike laid on its
  side
• Potential for high moment on rack and clamp

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Rotisserie Concept
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Rotisserie Concept

• Pros ()
• High pivot point of rotation, good clearance
  between pedals and roof of vehicle.
• Minimized moment, since pivot axis of bicycle is
  near the center of gravity of the bike.
• Quick release pivot clamps are tried and proven
  means of locking the bike horizontally.
• Cons (-)
• High pivot point of rotation may limit overall
  vehicle height.
• Length of bike carrier is limited by the cross
  bar spacing.
• Potential cost may be expensive.

10
Roller Assist Concept
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Roller Assist Concept

• Pros ()
• Uses existing crossbars as a rail system to lower
  the bike.
• Adjustable torsion springs will aid in controlled
  lowering of the bike.
• Spring assist will allow the bike to raise with
  reduced effort.
• Cons (-)
• Since crossbars are used as a rail system, only
  one bike can be accommodated on the car.
• Kinematics involved in designing the spring
  linkages may be overly complex.

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Rear Sliding Concept
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Rear Sliding Concept Pros ()

• Pros()
• Sliding the bike off of the rear of the car can
  reduce height dramatically.
• Added bonus of the rear sliding mechanism would
  allow a user to load the bike at a lower level
  than roof height.
• Aesthetically the design mimics a standard fork
  mount bike carrier
• Cons (-)
• Roller wheels may damage paint surfaces on the
  rear of the car.
• Extendable slide rails may be difficult to
  package in a small space.
• Possibility of the extendable side rails damaging
  the paint finish of the car.

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Pneumatic Shock Concept
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Pneumatic Shock Concept

• Pros ()
• Compact design
• Controlled method of lowering the bike using the
  pump handle to increase internal shock
  pressure.
• Assisted raising of bike when bypass valve is
  released.
• Cons (-)
• Power and pressure required to raise and lower a
  bike is unknown.
• Pumping action used to lower the bike may be time
  consuming.