Controls for hydrostatic systems

In a control for a hydrostatic drive system with a primary energy source and with at least two adjustable pumps driven by a common power source and at least one adjustable consumer of hydrostatic energy and with a pump adjusting piston connected with the adjusting element of each of the at least two pumps and capable of sliding in a pump adjustment cylinder, where the load on the pump adjustment cylinder of each of the at least two pumps is regulated by means of a separate servo control valve, and a constant pump connected to and driven by the power source in common with said at least two adjustable pumps;

• a delivery line connected to and receiving fluid from said constant pump, a restrictor in said delivery line, a signal-pressure line connected to the delivery line in front of the restrictor, a control-signal line connected to each servo control valve, a relief valve jet in said control-signal line and connected to and regulated by said signal pressure line, the improvement characterized in that the control-signal line is bifurcated between the relief valve jet and each servo control valve and an additional restrictor is located in the bifurcated control-signal line to provide a pressure gradient and means are provided for operatively connecting the two sides of the bifurcated signal line to the separate servo control valves whereby to control the loading of the pump adjusted cylinder.