Patent ID: 7810591

Claim:
A traveling device, comprising: a plurality of wheels disposed in parallel; a vehicle main body provided between the plurality of wheels and installed with a mechanism for driving the plurality of wheels; a handle that is mounted on the vehicle main body; a first support portion located on a lower rear side of the vehicle main body; a second support portion connected to the first support portion via a first rotary shaft; a caster connected to the second support portion via a second rotary shaft; an elastic member to elastically restrain the second support portion within a predetermined range; and a stop mechanism to limit movement of the second support portion toward the plurality of wheels, wherein a perpendicular is defined as a line extending from the first rotary shaft to a ground surface, wherein, when the vehicle main body is tilted to a horizontal position: (1) the second support portion is disposed in a predetermined position by the elastic member, (2) the caster is pulled away from the ground surface, and (3) the caster is disposed on the opposite side of the perpendicular as the plurality of wheels, wherein, when the vehicle main body is tilted to a predetermined angle such that the position of the second rotary shaft is located on the same side of the perpendicular as the plurality of wheels: (1) the plurality of wheels and the caster are brought into contact with the ground surface, and (2) the handle and vehicle main body support themselves, wherein, when the vehicle main body is tilted beyond the predetermined angle: (1) the plurality of wheels are pulled away from the ground surface, and (2) the caster is rotated without restraint so that the vehicle main body can be pulled by holding the handle, and wherein, when the caster comes into contact with the ground surface while the vehicle is traveling with a driver riding thereon, the second support portion is displaced from the predetermined position according to a reactive force exerted by the ground surface on the caster, such that the second rotary shaft is displaced away from the plurality of wheels.