Patent ID: 6951259

Claim:
A vehicle comprising: a steering operation device for turning said vehicle right or left, wherein the manipulated degree of said steering operation device from its position for making said vehicle travel straight is increased so as to increase the turning angle of said vehicle; a pair of right and left unsteerable running-driving wheels disposed at one of front and rear portions of said vehicle coaxially to each other, wherein said right and left running-driving wheels are differentially driven by manipulating said steering operation device for turning said vehicle right or left so that a turning center of said vehicle moves along a line extended axially of said right and left running-driving wheels; a traveling and steering transmission system including a hydrostatic transmission which includes mutually fluidly connected pump and motor, wherein said traveling and steering transmission system is coupled to said steering operation device and to said right and left running-driving wheels, such that manipulation of said steering operation device causes the hydrostatic transmission to increase the rate of rotation of one of said right and left running-driving wheels and decrease the rate of rotation of the other of said right and left running-driving wheels; a pair of right and left steerable running wheels disposed at the other of front and rear portions of said vehicle, wherein said right and left steerable running wheels are revolved laterally by manipulating said steering operation device for turning said vehicle right or left; and a steering mechanism interposed between said pair of steerable running wheels and said steering operation device, said steering mechanism including a pair of gear trains, each of the gear trains including mutually meshing first and second gears, wherein said first gear interlocks with said steering operation device, wherein said second gear interlocks with each of said steerable running wheels, and wherein said first and second gears of said pair of gear trains in said steering mechanism turn laterally so as to revolve said pair of steerable running wheels laterally according to manipulation of said steering operation device so that each of said steerable running wheels turns perpendicular to a radial line from said turning center of said vehicle, each of said gear trains including a rod pulled and pushed by manipulation of said steering operation device, wherein said first gear is an irregularly circular driving gear which is pulled and pushed by said rod so as to rotate, and wherein said second gear is an irregularly circular driven gear which meshes with said first gear so as to be rotated integrally with the turning of each of said steerable running wheels.