Control mechanism for a dual hydrostatic transmission vehicle drive system

In a vehicle having a dual hydrostatic transmission drive system, said dual hydrostatic transmission including first pump and motor units and second pump and motor including first pump and motor units and second pump and motor units for independent operation of said vehicle's drive wheels, said first and second pump units have a respective displacement control shaft extending from said pump units for independent displacement said respective pump units, a control mechanism comprising:

• a first lever fixably mounted to said first pump unit's control shaft;
• a second lever fixably mounted to said second pump unit's control shaft;
• a cross member having a generally horizontal orientation;
• a first connecting rod pivotally mounted to said first lever and pivotally mounted to one end of said cross member;
• a second connecting rod pivotally mounted to said second lever and pivotally mounted to the outer end of said cross member;
• a steering column fixably mounted to such cross member and extending generally vertically therefrom;
• support means for supporting said steering column, and allowing said steering column to be pivoted about said support means in a forward and rearward direction and allowing rotation of said steering column about the longitudinal centerline of such steering column, including, a first member having a generally cylindrical shape placed around a portion of said steering column;
• a plurality of pins fixably mounted in and extending through said steering column and first member;
• an elastromeric member having a generally cylindrical shape fixably mounted around a portion of said first member;
• housing open at opposing ends having said elastromeric member fixably mounted therein such that said steering column extends through said housings open ends;
• first means for fixably mounting said housing in said vehicle, whereby pivoting of said steering column causes said pump units to displace with a constant relative displacement, and rotation of said steering column causes said pump units to displace with a differential relative displacement.