Product+Contract+v3


 * GEARED WHEELCHAIR**

2.009 Team Yellow Product Contract Updated: 11/03/06

advantage to traverse multiple terrains and surfaces more easily.
 * Product Description:** A pair of replacement wheels that offers wheelchair users a mechanical
 * Intended Customers:** Wheelchair users
 * Market:** Retrofit wheelchair accessories


 * **Customer Need** || **Product Attribute(s)** || **Engineering Specification(s)** ||
 * Eases traversal of wide array of surfaces and slopes || Mechanical advantage || Reduce force input by 25% relative to the input required by a standard wheel to achieve the achieve the same force output ||
 * || Anti-rollback feature || Can counter a backward torque of at least 130N*m ||
 * Ability to shift between configurations at any time || Change shifter setting while in motion || Binary: yes ||
 * || Change shifter setting while stationary || Binary: yes ||
 * || Time required for user to change shifter setting || Less than 2 seconds ||
 * || Time required for user to engage/disengage uphill feature || Less than 2 seconds ||
 * || Time required for user to engage brake || Less than 1 second ||
 * || Location of shifter adaptable to user’s dominant hand || Binary: yes ||
 * || Number of hands required to shift || 1 ||
 * Reduces sliding friction between user’s hands and parts of moving wheels || Amount of sliding friction between user’s hands and parts of moving wheels || No rotational sliding friction between user’s hands and parts of moving wheels ||
 * Unobtrusive appearance || Appearance similar to standard manual wheelchair || 80% of general public cannot tell the difference between our product and standard manual wheelchair from a distance of 15 feet ||
 * Easily transportable || Added weight || Less than 10 lbs of total additional weight ||
 * || Time for wheel release || Added time for wheel release is less than 5 seconds relative to standard wheels ||
 * || No impact on wheelchair ability to collapse || Added time to fold wheelchair is less than 5 seconds relative to standard wheels ||
 * Maintains ergonomics of standard manual wheelchair || Size of rim || Rim diameter is within 2 inches of standard wheelchair ||
 * || Rotational backlash in rim || Less than 10 degrees of rotational backlash in rim ||
 * || Location of brake || Brake interface is within 6inches of hand rim ||
 * Maintains maneuverability of traditional wheelchair || Wheels can be driven forwards and backwards || Binary: yes ||
 * || Wheelchair width || Modified wheelchairs with widths that fall in the 25th to 75th percentile have a clearance of 4inches through an ADA specified thruway ||
 * Lasts as long as standard manual wheelchair || Product lifetime || Lasts 1.5 million rotations of the wheel (~5 years) with a wheelchair occupant of 250lbs ||