1,198,983. Pump servocontrol; fluid regulation. JOSEPH LUCAS (INDUSTRIES) Ltd. Oct.13, 1967 [July 15, 1966], No.31879/66. Headings G3H and G3P . The output pressure of a swash-plate pump is maintained constant by means of piston 2 which is subjected on its left-side to output pressure and on its right-side to the pressure in a receiver nozzle 11 supplied by a discharge nozzle 8, the jet between these nozzles interacting with a control jet issuing from nozzle 14 supplied through restriction 13. A spring biases the piston to a maximum displacement position.