Patent ID: 7493975

Claim:
A four-wheel vehicle comprising: a prime mover; a pair of left and right steerable wheels; a pair of left and right non-steerable driving wheels; a transmission system for transmitting power of the prime mover to the pair of left and right non-steerable driving wheels and for independently controlling rotational speeds of the left and right non-steerable driving wheels; a steering operation device for steering the pair of left and right steerable wheels, wherein the steering operation device is operatively connected the transmission system so as to control a differential rotation of the left and right non-steerable driving wheels; a pair of left and right gear assemblies interposed between the steering operation device and the respective left and right steerable wheels, wherein, in each of the gear assemblies, a first non-circular gear operatively connected to the steering operation device meshes with a second non-circular gear operatively connected to each of the left and right steerable wheels, and wherein, by operating the steering operation device for turning the vehicle, the left and right steerable wheels are able to be directed in the substantially traverse direction of the vehicle; a link member extended leftward and rightward from the steering operation device and pivoted at a lateral center thereof; and a pair of left and right link rods fore-and-aft extended from respective left and right ends of the link member and connected to the respective left and right first non-circular gears.