Independent metering valve assembly for multiple hydraulic load functions

Abstract

A hydraulic system, particularly suitable for use in a work machine, is provided with a hydraulic pressure source. A first hydraulic load is associated with a first load function. A second hydraulic load is associated with a second load function. An independent metering valve assembly includes a plurality of independently and electronically controllable valves. The independent metering valve assembly includes an inlet fluidly coupled with the pressure source, a first outlet fluidly coupled with the first hydraulic load, and a second outlet fluidly coupled with the second hydraulic load. The hydraulic system is configured such that the independent metering valve assembly may operate and drive multiple hydraulic load functions.

1 . A hydraulic system, comprising: 
 a hydraulic pressure source;    a tank;    a first hydraulic load associated with a first load function;    a second hydraulic load associated with a second load function; and    an independent metering valve assembly including a single first independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the first hydraulic load, a single second independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the second hydraulic load, and a single third independently controllable infinitely variable valve structured and arranged to control flow from one of the first and second independently controllable infinitely variable valves to the tank; said first and second independently controllable infinitely variable valves having inlets concomitantly fluidly connected to the hydraulic pressure source through a common inlet,    wherein said first load is independently and separably operable relative said second load through said independent metering valve assembly.    
   
   
       2 - 5 . (canceled)  
   
   
       6 . The hydraulic system of  claim 1 , including a single fourth independently controllable infinitely variable valve structured and arranged to control flow between the other of said one of the first and second independently controllable infinitely variable valves and said tank.  
   
   
       7 . The hydraulic system of  claim 1 , including a first pressure sensor fluidly coupled with an outlet of said first independently controllable infinitely variable valve and a second pressure sensor fluidly coupled with an outlet of said second independently controllable infinitely variable valve.  
   
   
       8 . The hydraulic system of  claim 7 , said independent metering valve assembly including said first pressure sensor and said second pressure sensor.  
   
   
       9 . The hydraulic system of  claim 1 , said pressure source being a hydraulic pump.  
   
   
       10 .- 19 . (canceled)  
   
   
       20 . A hydraulic system, comprising: 
 a hydraulic pressure source;    a tank;    a first hydraulic load associated with a first load function;    a second hydraulic load associated with a second load function; and    an independent metering valve assembly consisting essentially of: a first independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the first hydraulic load, a second independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the second hydraulic load, and a third independently controllable infinitely variable valve structured and arranged to control flow to the tank from one of the first and second valves; and    said first and second valves having inlets fluidly connected to the hydraulic pressure source through a common inlet to said metering valve assembly;    wherein said first load is independently and separably operable relative to said second load through said independent metering valve assembly.    
   
   
       21 . A hydraulic system, comprising: 
 a hydraulic pressure source;    a tank;    a first hydraulic load associated with a first load function;    a second hydraulic load associated with a second load function; and    an independent metering valve assembly consisting essentially of: a first independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the first hydraulic load, a second independently controllable infinitely variable valve structured and arranged to control flow between the hydraulic pressure source and the second hydraulic load, a third independently controllable infinitely variable valve structured and arranged to control flow to the tank from one of the first and second valves, and a fourth independently controllable infinitely variable valve structured and arranged to control flow to the tank from the other of the first and second valves; and    said first and second valves having inlets fluidly connected to the hydraulic pressure source through a common inlet to said metering valve assembly;    wherein said first load is independently and separably operable relative to said second load through said independent metering valve assembly.