Abstract: A dashpot assembly has a movable cylindrical element mounted within a housing. The movable element has a chamber with a first opening for restricting flow of fluid into the chamber and a second opening for permitting rapid flow of fluid out of the chamber. An enlarged head is disposed inside the chamber and is coupled to a poppet with a spring coupled between the poppet and the movable element. When the poppet moves in a direction away from the movable element, the enlarged head closes the second opening and pulls the element. Fluid then flows into the chamber only through the restricted first opening, thereby damping the rate of movement of the poppet. When the poppet moves in a direction toward the movable element, the enlarged head opens the second opening and the spring is effective to move the element in the same direction; fluid flows unrestricted through the second opening, thereby permitting an undamped movement of the poppet.

Abstract: A closed center programmed valve system having a load sense fluid source for control of the raising and lowering of load means by a raise and a lower normally closed two stage valve assembly. Each of the second stages of the valve assemblies has a poppet with a parabolic contour which is dimensioned to provide substantially linear flow rate change for minimized shock when the respective valve is actuated to the valve closed state. The load sense for the load means is taken from the outlet of the raise second stage without the requirement of a separate actuated valve or land with a load sense signal being applied to the fluid source during the time the raise valve assembly is actuated to the valve open state.

Abstract: A dashpot assembly has a movable cylindrical element mounted within a housing. The movable element has a chamber with a first opening for restricting flow of fluid into the chamber and a second opening for permitting rapid flow of fluid out of the chamber. An enlarged head is disposed inside the chamber and is coupled to a poppet with a spring coupled between the poppet and the movable element. When the poppet moves in a direction away from the movable element, the enlarged head closes the second opening and pulls the element. Fluid then flows into the chamber only through the restricted first opening, thereby damping the rate of movement of the poppet. When the poppet moves in a direction toward the movable element, the enlarged head opens the second opening and the spring is effective to move the element in the same direction; fluid flows unrestricted through the second opening, thereby permitting an undamped movement of the poppet.

Abstract: A hydraulic oscillator in which a piston reciprocates between first and second positions in a cylinder. A reversing pilot valve controls fluid flow to ends of the cylinder and flow through first and second pilot passages control the reversing operation of the pilot valve. The cylinder has a pilot channel or groove coupled to a pilot supply line. The piston has (1) a first logic channel for fluidly coupling the pilot channel and first pilot passage as the piston approaches the second position and (2) a second logic channel for fluidly coupling the pilot channel and second pilot passage as the piston approaches the first position thereby to alternately reverse the pilot valve and produce the reciprocation of the piston.

Abstract: A programmed valve system for positioning control having a first two stage valve assembly operable for raising a load and a second two stage valve assembly for lowering the load. Each of the second stages has a poppet with a parabolic contour which is dimensioned with orifice parameters to provide substantially linear flow rate change for minimized shock when one of the second stage poppets closes and the other opens. In the raise assembly, the pilot stage outlet orifice has a cross-sectional area substantially larger than that of the inlet orifice so that the second stage poppet opens much more rapidly than the closing thereof thereby to minimize overshoot when the pilot stage is actuated to the open position.

Abstract: A closed center programmed valve system having a load sense fluid source for control of the raising and lowering of load means by a raise and a lower normally closed two stage valve assembly. Each of the second stages of the valve assemblies has a poppet with a parabolic control which is dimensioned to provide substantially linear flow rate change for minimized shock when the respective valve is actuated to the valve closed state. The load sense for the load means is taken from the outlet of the raise second stage without the requirement of a separate actuated valve or land with a load sense signal being applied to the fluid source during the time the raise valve assembly is actuated to the valve open state.

Abstract: A valve system for an unbalanced load having a first two stage valve assembly operable for raising the load and a second two stage valve assembly for lowering the load. Each of the second stages has a poppet with a parabolic contour which is dimensioned with orifice parameters to provide substantially linear flow rate change when the second stage poppet moves for substantially zero flow jerk. In addition, the raise valve assembly has a pilot line coupled directly to the load so that high pressure oil is instantly available to actuate the second stage poppet. The lower valve assembly has a dashpot to decrease the rate of opening of that second stage poppet.

Abstract: A feathering valve system for modulating the fluid inflow to a selected one of first and second chambers of a movable biased assembly. A controller is electrically coupled to a first and second solenoid operated pilot valve assemblies for selectively (1) maintaining the pilot valve assemblies in a valve closed state without bleed flow through the pilot orifices or (2) supplying a predetermined value electrical signal to either, but not both, of the valve assemblies for actuating one of the assemblies to an open position related to the value of the signal. Fluid under a substantially constant pilot pressure is applied under the poppets of both valve assemblies. Fluid flow is taken from above the poppet of an actuated valve assembly to a respective chamber whereby the movable assembly moves to a position which is a function of the actuating signal value.

Abstract: A feathering valve system for modulating the fluid inflow to a selected one of first and second spool ends of a spool valve assembly. A controller is electrically coupled to first and second solenoid operated pilot valve assemblies for selectively (1) maintaining the pilot valve assemblies in a valve closed state without bleed flow through the pilot orifices or (2) supplying a predetermined value electrical signal to either, but not both, of the valve assemblies for actuating one of the assemblies to an open position related to the value of the signal. Fluid under a substantially constant pilot pressure is applied under the poppets of both valve assemblies. Fluid flow is taken from above the poppet of an actuated valve assembly to a respective spool end whereby the spool moves to a position which is a function of the actuating signal value.

Abstract: An attachment for converting a farm tractor to a front end loader having front and upwardly extending frame members, a pair of boom arms and an implement. Hydraulic cylinders actuate the boom arms and implement. An electrohydraulic valve assembly is hydraulically coupled to the cylinders and is rigidly secured to the attachment outside of the cab. A switching assembly electrically switches the electrohydraulic valve assembly and is secured within the cab for easy access to the operator of the tractor. An electrical cable is coupled between the switching assembly within the cab and the electrohydraulic valve assembly outside of the cab.

Abstract: A tractor towed vehicle having a frame and hydraulic functions powered by a plurality of hydraulic devices. An electrohydraulic valve assembly is coupled to the devices and is rigidly secured to the frame of the towed vehicle. A switching assembly having a plurality of switches is adapted for electrically switching the valve assembly with a cable coupled between the switching assembly and the valve assembly. The switching assembly is disposed within the tractor cab for easy access of the plurality of switches to the operator of the tractor.

Abstract: A two stage solenoid actuated valve and method of actuation within a predetermined time interval. The valve provides fluid flow having a predetermined flow profile for displacement of a mass through a particular distance with a minimization of shock applied to the mass. The valve has a first and second stage in fluid communication each with the other. The first stage includes a solenoid valve and associated plug member for opening or closing flow through the first stage. The second stage includes a plug member having a predetermined contour head insertable within an orifice whose movement is responsive to the flow state of the first stage.

Abstract: A normally closed solenoid operated valve assembly having a poppet movable between a valve normally closed position seating in and closing in orifice and a valve normally open position. A movable armature has a reduced section for engaging and pulling the poppet to the open position. A range spring tends to bias the poppet closed until the upstream force of fluid is sufficient to overcome the spring force. The spring force may be adjusted to vary to a predetermined value the upstream force of fluid. To open the valve, a solenoid is energized to move the armature thereby to move the poppet to the open position.