US Patent 7419181 Foldable carriage body for carrying a seat

A seat carriage body comprises a front leg, a rear leg, a push rod, and position fixing means. An upper end of the front leg is turnably connected to an upper end of the rear leg through a first shaft. A front end member of the push rod is connected to the front leg such that it can be displaced along the front leg at the time of a folding operation. A middle part of the push rod is turnably connected to the rear leg through a second shaft. The position fixing means fixes a positional relation among the front leg, the rear leg and the push rod in both open and folded states.