US Patent 7188858 Foldable stroller

A stroller having a novel frame geometry that provides a more direct structural tie between the front and the rear wheels. The two rear legs (bottom members) of the frame are disposed at a relatively small angle to the horizontal and remain close to that shallow angle as the stroller is folded, with all four wheels on the ground. The rear leg assembly is pivotally linked to the front leg assembly, so that the front leg assembly collapses onto the rear leg assembly when the stroller is folded. The front legs and the rear legs preferably have a similar profile so that they generally nest when folded. The front legs and the rear legs preferably have oval or oblong cross-sections, which enhances their vertical load strength.