Team 8 UH

Technical Problem Statement The objective of this project is to design and validate a purely mechanical, retractable stair-climbing mechanism that can integrated into a standard checked suitcase. The system must safely transport a 70 lb load over typical 7–8 inch stair risers while reducing user-applied pulling force to below 187 N. The mechanism must fully retract within airline dimensional limits (L + W + H ≤ 62 inches), maintain a minimum structural safety factor of 2 under worst-case loading, and remain stable during stair ascent and descent. The major challenge is transferring the suitcase’s weight through a deployable tri-wheel  with a retractable/folding  mechanism (figure 2)  without structural failure, tipping, or excessive user effort. During stair climbing, concentrated reaction forces occur at stair edges, generating bending in the axle, shear in locking interfaces, and moment loading on the hinge structure. The design must balance mechanical advantage, packag...

  Background and Motivation Many travelers regularly encounter stairs in places such as airports, train stations, subways, and hotels when elevators are unavailable or out of service. In these situations, moving a large suitcase becomes difficult and unsafe. Most checked suitcases weigh up to 50 lb and are designed to roll only on flat surfaces. When faced with stairs, users must lift the full weight of the suitcase while maintaining balance on narrow steps, which increases physical strain and the risk of injury. According to the American Academy of Orthopedic Surgeons, this has resulted in 85,000  people being sent to the emergency room due to luggage related injuries as recently as 2017.  This  problem is especially challenging for smaller or petite users and those with  limited lifting strength. Of  those who suffered from luggage related shoulder injuries, around 60% were female and over the age  of 50. A  mechanical solution that assists user...