US Patent 10028870 Powered wheelchair

The invention relates to a powered wheelchair for transporting a person, comprising a seat frame for supporting the person, a pair of opposing main wheel assemblies, including a first main wheel assembly and a second main wheel assembly connected to the seat frame, and a third main wheel assembly arranged spaced apart from the pair of opposing main wheel assemblies and connected to said seat frame. The powered wheelchair further comprises a support wheel arrangement for supporting the powered wheelchair, said support wheel arrangement having a main beam and a front support wheel unit capable of being applied to a ground surface. The main beam is rotatably connected to said third main wheel assembly at a third connection point and connected via a guiding mechanism to the first main wheel assembly at a first connection point. The main beam has a first portion adapted to cooperate with said guiding mechanism when said first portion passes through a part of the guiding mechanism upon movement of the main beam relative to the guiding mechanism, to maintain said support wheel arrangement in a supporting position, in which the front support wheel unit is applied to the ground surface.