Abstract: A system and method for machinery performing work with hydraulic actuators. Radial hydraulic pumps are aligned end-to-end along a common driveshaft axis to form a multi-pump assembly having a plurality of piston/cylinder units extending in a radial direction. Two or more piston/cylinder units are associated with one another to form multiple piston/cylinder groups. A plurality of control valves combines individual output flows from the two or more associated piston/cylinder units into respective common output flows for each respective piston/cylinder group. A plurality of flow control devices varies the common output flow from each respective piston/cylinder group by throttling inlet flow to the two or more associated piston/cylinder units in each respective piston/cylinder group. Each respective common output flow is directed from each respective piston/cylinder group to a hydraulic actuator on the heavy machinery to control its direction of movement.

Abstract: A system and method for machinery performing work with hydraulic actuators. Radial hydraulic pumps are aligned end-to-end along a common driveshaft axis to form a multi-pump assembly having a plurality of piston/cylinder units extending in a radial direction. Two or more piston/cylinder units are associated with one another to form multiple piston/cylinder groups. A plurality of control valves combines individual output flows from the two or more associated piston/cylinder units into respective common output flows for each respective piston/cylinder group. A plurality of flow control devices varies the common output flow from each respective piston/cylinder group by throttling inlet flow to the two or more associated piston/cylinder units in each respective piston/cylinder group. Each respective common output flow is directed from each respective piston/cylinder group to a hydraulic actuator on the heavy machinery to control its direction of movement.

Abstract: A radial piston pump has a plurality of cylinders within which pistons reciprocally move. Each cylinder is connected to a first port by an inlet passage that has an inlet check valve, and is connected to a second port by an outlet passage that has an outlet check valve. A throttling plate extends across the inlet passages and has a separate aperture associated with each inlet passage. Rotation of the throttling plate varies the degree of alignment of each aperture with the associated inlet passage, thereby forming variable orifices for altering displacement of the pump. Uniquely shaped apertures specifically affect the rate at which the variable orifices close with throttle plate movement, so that the closure rate decreases with increased closure of the variable orifices.

Abstract: A radial piston pump has a plurality of cylinders within which pistons reciprocally move. Each cylinder is connected to a first port by an inlet passage that has an inlet check valve, and is connected to a second port by an outlet passage that has an outlet check valve. A throttling plate extends across the inlet passages and has a separate aperture associated with each inlet passage. Rotation of the throttling plate varies the degree of alignment of each aperture with the associated inlet passage, thereby forming variable orifices for altering displacement of the pump. Uniquely shaped apertures specifically affect the rate at which the variable orifices close with throttle plate movement, so that the closure rate decreases with increased closure of the variable orifices.

Abstract: A pilot operated valve has a main poppet that selectively controls flow of fluid between first and second ports in response to pressure in a control chamber on one side of the main poppet. The main poppet has an aperture extending between the control chamber and the first port. A pilot piston slides within the aperture and has the pilot passage with a pilot orifice and a first disk spring biases the pilot piston with respect to the main poppet. A pilot valve element selectively engages the pilot orifice to open and close the pilot passage and thereby controls motion of the main poppet. Forces from the first disk spring and a pressure differential between control and pilot chambers alter a position of the pilot valve seat with respect to the main poppet. The change in position compensates for effects on valve operation due to variation of the pressure at the two ports.

Abstract: A hydraulic valve has a main poppet that engages and disengages a valve seat to control the flow of fluid between an inlet and an outlet. Movement of the main poppet is governed by a pilot valve element the opens and closes a pilot passage in the main poppet. The pilot valve element is slideably received in a bore in an armature. The armature is biased toward the main poppet by a first spring and a second spring biases the pilot valve element outward from armature bore and toward the main poppet. The second spring has a lesser spring rate than the first spring. Upon engagement of the pilot valve element with the main poppet continued application of the engaging force causes the second spring to collapse and the pilot valve element to slide within the armature, thereby absorbing some of the force that could otherwise adversely affect the valve.

Abstract: A distributed hydraulic system locates a control assembly, that has electrohydraulic valves and a electronic controller, adjacent the respective hydraulically powered actuator controlled by that assembly. The control assembly includes a manifold block with ports to that the pump, tank return and actuator fluid conduits connect. One or more pressure ports are provided on the manifold block at which to sense pressure at different locations therein. A controller housing, in addition to containing an electronic function controller, also contains a separate pressure sensor for each pressure port, and is mounted against the manifold block so that each pressure sensor connects to a pressure port. The manifold block also has a pair of exterior walls that extend on opposites sides of the controller housing to protect the electronic controller. Other features that facilitate distributing the hydraulic control adjacent the actuators are provided.

Abstract: A pair of hydraulic cylinders 10 which are coupled to a driven member, placed parallel to each other and extend/contract in synchronization with each other, and a control valve 20 which controls hydraulic fluid supplied to or discharged from the hydraulic cylinder 10 are provided. An elastic support mechanism 50 which supports the control valve 20 to each hydraulic cylinder between the paired hydraulic cylinders 10; metallic piping 30 and the metallic piping 40 which connect the control valve 20 with the respective hydraulic cylinders 10 and leads the hydraulic fluid controlled by the controlling valve 20; and curved portions 31c, 32, 41c, 42a which are provided at some midpoints of the piping and flexibly deform in accordance with relative deformation of each hydraulic cylinder 10 are provided. A difference in relative displacement of each hydraulic cylinder with respect to the control valve 20 is absorbed by deformation produced in the elastic support mechanism 50 and the curved portions.

Abstract: Operation of an electrically operated valve is calibrated by applying a gradually increasing electric current to the valve. While that is occurring pressure at either the inlet or outlet of the valve is measured to detect when the valve opens. When the valve opens the level of the electric current then being applied to the valve is employed to determine an initial current level to use subsequently whenever the valve is to be opened.

Abstract: A hydraulic valve assembly includes a pilot operated proportional poppet valve in which the main poppet moves in response to pressure in a first control chamber. The pressure in a first control chamber is governed by a pilot poppet and movement of the main poppet controls fluid flow between a first inlet and a first outlet. A shadow poppet valve has a shadow poppet that controls fluid flow between a second inlet and a second outlet in response to pressure in a second control chamber. The first and second control chamber are connected together whereby the pilot operated proportional poppet valve and the shadow poppet valve open and close together. A unique hydraulic system utilizing a plurality of these hydraulic valve assemblies to operate two operators alternately in parallel or in series is described.