Traveling device for smooth and stable movement on uneven and inclined surfaces

A traveling device, comprising:

• a truck member acting as a platform and having a loop frame, a pair of front and rear casters and a pair of left and right driving wheels for supporting the loop frame, said loop frame consisting of a pair of side frame parts, a front part and a rear part, each side frame part having a front section and a rear section divided by a bendable portion at which the side frame part is able to bend upwards and downwards, said bendable portions being formed at a pair of opposed lengthwise middle portions of the side frame parts, said pair of casters supporting a pair of lengthways middle portions of the front and rear frame parts, said pair of driving wheels supporting the pair of opposed lengthwise portions of the side frame parts, and allowing the truck member to move frontwards and backwards;
• and
• a body member having a front body portion which is supported by a pair of links, and a rear body portion which is supported by a pair of fixed arms, said each link having an upper end and a lower end, the lower end of each said link being connected to the front section of the respective side frame part, said each fixed arm having an upper end and a lower end, the lower ends of each fixed arm being connected to the rear section of the side frame part, characterized in that the loop frame is divided into a generally U-shaped front half-frame defined by the front frame part and the front sections of the side frame parts, and a generally U-shaped rear half-frame defined by the rear frame and the rear sections of the side frame parts;
• wherein said front half-frame has a pair of leading ends, which are opposed, respectively, to a pair of leading ends of the said rear half-frame, and the loop frame has a pair of supporting arms, each of which is protruding from one of the opposed leading ends of the front and rear half-frames;
• wherein a rotation axis of each said driving wheel is rotatably connected to the supporting arm, while the supporting arm is also connected to the other of the opposed leading ends of the front and rear half-frames at the bendable portion which is located below the rotation axis of the driving wheel;
• wherein said loop frame is formed into a horizontal form as seen from left and right sides, and wherein the upper and lower ends of the each link is rotatably connected so as to move generally parallel to a traveling direction into which the driving wheel is heading, whereby the upper end of each said fixed arm is fixed immovably, while the lower end of each said fixed arm is rotatably connected at the lower end so as to move generally parallel to the traveling direction.