Hydraulic control system

A hydraulic control system comprising:

• (a) variable output pumping means having an outlet and a signal inlet adapted to receive a signal pressure for varying the pumping means output;
• (b) a plurality of hydraulic valve control sections each of which comprises
• (i) a valve body defining an inlet connected to the pumping means outlet, at least one work port adapted for connection to a hydraulically actuated device and a signal pressure outlet;
• (ii) power spool means for selectively blocking and establishing fluid communication under variable pressure between the inlet and the associated work port;
• (iii) a signal pressure chamber;
• (iv) control means for establishing fluid communication between the work port and signal pressure chamber when the power spool means connects the inlet to the work port;
• (v) and check valve means constructed and arranged to permit the flow of hydraulic fluid only from the signal pressure chamber to the signal pressure outlet;
• (c) the signal pressure outlets of the respective valve sections being commonly connected to the signal inlet of the variable output pumping means, whereby the greatest signal pressure of the plurality of valve control sections is transmitted to and controls the pumping means.