Abstract: A power regulating device for a hydrostatic pump with at least one pressure-loaded piston which adjusts a stroke-varying member and is controlled by a valve with two springs acting upon one side of the valve and a gauge piston loaded by the delivery pressure and a lever through which a force proportional to the delivery pressure acts upon the other side of the valve, is provided with an additional spring which acts upon the gauge piston via an intermediate member in the same direction in which the delivery pressure acts, and with a second pressure medium source arranged to act with a variable control pressure upon the intermediate member against the additional spring.

Abstract: An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a discharge rate which corresponds to the speed of rotation of the drive. A throttle valve is located in a discharge conduit of the auxiliary pump, and the pressure of the control fluid upstream of the throttle valve controls the displacement of a slide valve between two positions thereof in one of which the control slide controls the variable-output pump toward increasing the output thereof, while in the other of such positions the pump is controlled toward a reduced output thereof. In addition to the pressurized fluid, which acts on the control slide with a first force, a spring is provided which acts on the control slide with a second force opposing the first force.

Abstract: An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a rate corresponding to the speed of rotation of the drive into a discharge conduit in which a variable flow-through cross-sectional area throttle valve is located. The pressure in the discharge conduit upstream of the throttle valve controls the displacement of a control slide between the two end positions thereof in one of which the control slide controls the variable-output pump so as to increase the output thereof, while in the other of such positions of the control slide the pump is controlled so as to reduce the output thereof. The throttle valve is responsive to the pressure in the discharge conduit, but can be arrested in any position thereof when the drive is overloaded so that the flow-through cross-sectional area thereof is fixed, which results in a decrease of output of the variable-output pump when the drive is overloaded.

Abstract: A multiple pump assembly consisting of a series of two or more coaxial pumps the first of which is invariably a radial piston pump. The shaft of the prime mover drives the first pump by way of an Oldham coupling and an extension of this shaft extends through an axial bore of the pintle in the first pump to drive the rotary element of the second pump as well as any further pump of the assembly. If the second pump is also a radial piston pump, the two pumps may but need not have a common pintle. The slide block of each radial piston pump can be adjusted to change the rate of delivery of pressurized fluid. The fluid admitting and evacuating channels in the pintle or pintles may be formed by an electrochemical process, or the entire pintle may constitute a casting. The housing for the multiple pump assembly may include a discrete annular section for each pump or a single annular section for all of the pumps and cover members at the axial ends of the single section.