Abstract: A roller assembly provides collision protection and stability to a mobile robot. The roller assembly includes a shaft forming an axis about which the roller assembly can rotate. The shaft has opposite ends configured to be supported by bearings in the robot. The roller assembly also includes an impact absorbing layer coaxially covering the shaft. It further includes a shell coaxially covering the impact absorbing layer having a lower coefficient of friction than the impact absorbing layer for providing low sliding friction.

Abstract: A cost effective bumper for a vehicle is provided that develops maximum resiliency of an inflated spare wheel to dampen shock of impacts so as to reduce injury to the occupants and reduce repair cost of the vehicle, without need for additional parts or cost. The bumper is especially suited to increase the safety of small automobiles, and storage of the spare wheel in the bumper assembly gives added room in the luggage compartment. The introduction of Hybrid power plants for small automobiles allows timely opportunities for new placements of engine components, to best accommodate the bumper assembly of the present invention.