US Patent 10392041 Folding chassis for manually driven carrier vehicles

Disclosed is a foldable chassis of manually driven carrier vehicles capable of self-locking in unfolded position. The chassis includes a frame having a reference plane, an actuator attached pivotally to said frame, a first mechanism comprising said actuator and a platform attached pivotally to said frame, and a second mechanism comprising said actuator and two arms, each attached to said frame pivotally around a first axis and configured for attaching a wheel arrangement rotatable around a second axis. Said first and second mechanisms configured to move independently of each other between at least a first position, in which said platform generally perpendicular to said frame and said wheel arrangements generally perpendicular to said reference plane, and a second position, in which said platform adjacent to said frame and said wheel arrangements adjacent and parallel to said reference plane.