Steering And Ground Speed Control Mechanism Of A Dual-Path Hydrostatic Drive Arrangement

In a vehicle equipped with a dual-path hydrostatic transmission for driving a pair of ground wheels of the vehicle, a steering and ground-speed control mechanism, comprising:

• an elongate gear support member mounted for pivoting about a first upright axis;
• a gear train including a steering input gear, an idler gear and a steering output gear, with said idler and output gears each being mounted to said gear support member for respectively rotating about a second upright axis and a third upright axis;
• a steering wheel being coupled to said steering input gear for selectively rotating the input gear in opposite directions from a centered position corresponding to a straight ahead driving condition of the vehicle;
• said hydrostatic transmission including first and second pumps respectively having first and second displacement control arms;
• a control plate arrangement including said output gear;
• first and second control rods extending crosswise to a line of centers of said input, idler and output gears and having first ends respectively pivotally connected to said control plate arrangement and being rotatable with said output gear, and having second ends respectively coupled to said first and second displacement control arms, with said first ends being so located relative to said third upright axis that rotation of said output gear will cause one of said control rods to pull on an associated one of said control arms and will cause another of said control rods to push on an associated other one of said control arms, and that swinging of said gear support member about said first upright axis selectively in opposite first and second directions from a neutral position, corresponding to a neutral position of said first and second displacement control arms will respectively increase the displacement of said first and second pumps respectively for increasing the drive speed of the pumps in forward and reverse driving operation.