Battery powered stair-climbing wheelchair

Abstract

A self-propelled battery-powered wheelchair replaces an ordinary wheelchair and provides improved access to homes. The wheelchair includes stair climbing, slope climbing, and reclining while requiring only minimal driver skill and strength. Operation on level ground is similar to the operation of a conventional wheelchair. Support for normal operation is provided by a rear caster and wheels on the front corners. Its compact width and length enable negotiating narrow doorways and turning in small spaces. To ensure stability on stairs, moveable skids are mounted to the four corners of the wheelchair. Parallelogram linkages move the front skids down and forward during climbing. Another parallelogram linkage moves the caster and rear skids up and at an angle during climbing. The wheelchair is steerable on stairs as needed to align with the stair path and accommodate slightly spiraling stairs. The wheelchair accommodates stair steps of different riser heights and tread lengths. A pair of spoked or spider wheels with small wheels at the ends of the spokes are rotably mounted to the sides of the wheelchair. The spider wheels engage the stairs to propel and stabilize the wheelchair during climbing of stairs. Methods are provided to monitor and control the pitch attitude of the wheelchair and nearness of wheelchair supporting components to the stairs. Motion and control are provided by electric motors, sensors, a computer, and driver inputs. Propulsion power for conventional level operation, slope climbing, and stair climbing operation is transmitted through the same motors and wheels.

Dependencies are inferred from the claim text.