Abstract: A travel bag is provided. The travel bag comprising: a frame having at least three wheels attached thereto, each of the wheels being configured to be contact to a ground; a case being configured to have an empty space to receive objects and also being configured to be disposed on the frame; and a pivot axis being located on or above the frame, the pivot axis being defined by two contact points or a contact line connecting the case and the frame. The case disposed on the frame is allowed to pivot on the pivot axis to draw a trajectory of an arc or a circle. All of the wheels are configured to be maintained as being continuously contact to the ground, regardless of the case's pivoting around the pivot axis.

Abstract: A travel bag is provided. The travel bag comprising: a frame having at least three wheels attached thereto, each of the wheels being configured to be contact to a ground; a case being configured to have an empty space to receive objects and also being configured to be disposed on the frame; and a pivot axis being located on or above the frame, the pivot axis being defined by two contact points or a contact line connecting the case and the frame. The case disposed on the frame is allowed to pivot on the pivot axis to draw a trajectory of an arc or a circle. All of the wheels are configured to be maintained as being continuously contact to the ground, regardless of the case's pivoting around the pivot axis.