Stairway with fail safe power lift for lading, the infirm, wheelchair patients, and the like

摘要

A combined stairway and power lift installable as a unit between upper and lower levels and including a fluid-powered lifting platform propelled along the stairs over an underlying pressure sensing mat extending beyond the approaches to the stairs and operable to disable the power to the lift and lock the lift stationary whenever and so long as a weight or pressure remains on the mat. Extendable and retractable barriers crosswise on the transverse edges of the lift must be held positively in a barricading position while the lift is en route between levels. The power system includes devices automatically operable to accelerate and decelerate the lift smoothly and shocklessly between zero and full speed while approaching and departing from a floor level as well as safety equipment for safeguarding against travel of the lift under all unsafe contingencies.