A trolley includes a main frame, a wheel device, a support frame attached to a front side of the main frame, and a foldable seat assembly attached to a rear side of the main frame. When the seat assembly is in an extended status, a second pair of stands secured to a first pair of stands contact the ground...http://www.google.sh/patents/US5161811?utm_source=gb-gplus-sharePatent US5161811 - Trolley with a foldable seat assembly
