Abstract: There is disclosed an hydrostatic transmission having a control and regulating device for adjusting the driving torque with superimposed output power limit regulation, the transmission comprising a drive unit comprising an hydraulic pump having a variable output, and an hydraulic motor arranged to be operated by the hydraulic pump; a servo-adjusting device arranged to control the output of the hydraulic pump in order to adjust the working pressure in the transmission, said device comprising a servo piston arranged for two-way adjustment of the hydraulic pump in two directions, and a control valve arranged to subject the servo-piston to an adjusting pressure so that the piston can adjust the operation of the hydraulic pump; a servo-valve spool provided in said control valve and arranged, in dependence upon the desired direction of adjustment of the hydraulic pump, to be subjected on the one hand to a control pressure and on the other hand to the working pressure prevailing in the transmission or a regulating p

Abstract: An output control apparatus for a hydrostatic drive in open circuit is described which has a device for regulating the delivery of the hydraulic pump. In addition to conventional output control by way of an output valve, the arrangement of an additional control piston which acts on the spool of the output valve provides the possiblity of adjusting the delivery as a function of the restoring pressure of a load during its working movement in a return direction, with reduced power consumption.