Control apparatus for several drive assemblies consisting of hydrostatic drive units

A control apparatus for a plurality of drive assemblies including hydrostatic drive units comprising:

• one or more first hydraulic pumps each having a total output control device and a capacity adjusting device;
• an output-preferred hydraulic pump having an adjustable output control device and a capacity adjusting device;
• a prime mover for driving said first output-preferred hydraulic pumps;
• said adjustable output control device including an adjusting piston connected to the capacity adjusting device of said one or more first hydraulic pumps, and a spool valve for controlling the pressure action of said adjusting piston on one side of said adjusting piston, said spool valve being connected on one side to a pressure line from said one or more first hydraulic pumps and said spool valve being acted upon on an opposing side by an adjustable spring;
• a first lever acting upon said adjustable spring, said first lever being supported by an adjustable fulcrum support means forming first and second lever arms, the length of said arms being adjustable;
• and
• a measuring piston which presses against said first lever to counteract the force of said adjustable spring acting upon the spool valve, said measuring piston being connected to a pressure line from said output-preferred hydraulic pump for controlling the action of the measuring pump.