Three state magnet valve

Abstract

A three-state magnet valve for control of fluid flow engageable with a source of fluid pressure for connecting the three-state magnet valve to a source of fluid pressure. The three-state magnet valve also has an application pilot solenoid valve having a fluid connection to a source of fluid pressure and is electrically connectable to a control module. The three-state magnet valve further has an application solenoid valve having a fluid connection to a source of fluid pressure and to an application pilot solenoid valve and a braking device. The application solenoid valve is also electrically connectable to a control module. The application solenoid valve is able to initiate a braking application upon receipt of a fluid signal from the application pilot solenoid valve and an electrical signal from a control module. The three-state magnet valve further has a release pilot solenoid valve having a fluid connection to a source of fluid pressure and to the application solenoid valve and is electrically connectable to a control module. The three-state magnet valve also has a release solenoid valve having a fluid connection to an exhaust to atmosphere and to the application solenoid valve and to the release pilot solenoid valve and to a braking device. The release solenoid valve is electrically connectable to a control module. The release solenoid valve is able to exhaust fluid pressure to atmosphere upon receipt of a fluid pressure signal from the release pilot solenoid valve and an electrical signal from a control module thereby exhausting fluid pressure from said braking device.

I claim:  
     
         1 . A three-state magnet valve for control of fluid flow, said three-state magnet valve comprising: 
 (a) a means engageable with a source of fluid pressure for connecting said three-state magnet valve to said source of fluid pressure;    (b) an application pilot solenoid valve having a fluid connection to said source of fluid pressure and electrically connectable to a control module;    (c) an application solenoid valve having a fluid connection to said source of fluid pressure and to said application pilot solenoid valve and a braking device and electrically connectable to such control module, said application solenoid valve initiating a braking application upon receipt of a fluid signal from said application pilot solenoid valve and an electrical signal from such control module;    (d) a release pilot solenoid valve having a fluid connection to said source of fluid pressure and to said application solenoid valve and electrically connectable to such control module; and    (e) a release solenoid valve having a fluid connection to an exhaust to atmosphere and said application solenoid valve and said release pilot solenoid valve and said braking device and electrically connectable to such control module, said release solenoid valve exhausting fluid pressure to atmosphere upon receipt of a fluid pressure signal from said release pilot solenoid valve and an electrical signal from such control module thereby exhausting fluid pressure from said braking device.    
     
     
         2 . A three-state magnet valve according to  claim 1 , wherein said braking device is a brake cylinder.  
     
     
         3 . A three-state magnet valve according to  claim 1 , wherein said means engageable with a source of fluid pressure for connecting said three-state magnet valve to said source of fluid pressure is a port.  
     
     
         4 . A three-state magnet valve according to  claim 1 , wherein at least one of said solenoid valves is of the 3-way, normally open type.  
     
     
         5 . A three-state magnet valve according to  claim 1 , wherein at least one of said solenoid valves is of the 3-way, normally closed type.  
     
     
         6 . A three-state magnet valve according to  claim 1 , wherein at least one of said solenoid valves is of the 2-way, normally open type.  
     
     
         7 . A three-state magnet valve according to  claim 1 , wherein at least one of said solenoid valves is of the 2-way, normally closed type.  
     
     
         8 . A method for wheel slip control using a three-state magnet valve, said method comprising the steps of: 
 (a) generating a signal in a control module;    (b) giving a command signal to at least one of a plurality of solenoid valves that allows a source pressure to be at least one of applied to, exhausted from and held stable at a braking device based on said signal generated.    
     
     
         9 . A method for wheel slip control using a three-state magnet valve according to  claim 8 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to de-energize said application pilot and said release pilot solenoid valves and allow said source of fluid pressure to enter said three state magnet valve and pilot at said application solenoid valve open to allow said source of fluid pressure to flow to said braking device.  
     
     
         10 . A method for wheel slip control using a three-state magnet valve according to  claim 8 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves which energizes said application pilot solenoid valve and allows a pilot pressure from said application solenoid valve to exhaust to atmosphere.  
     
     
         11 . A method for wheel slip control using a three-state magnet valve according to  claim 10 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to allow said application solenoid valve to close and hold said source pressure steady at such braking device.  
     
     
         12 . A method for wheel slip control using a three-state magnet valve according to  claim 8 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid valve and allow a pilot pressure to be supplied to said release solenoid.  
     
     
         13 . A method for wheel slip control using a three-state magnet valve according to  claim 12 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to open said release solenoid and allow a fluid pressure to exhaust from said braking device to atmosphere.  
     
     
         14 . A method for wheel slip control using a three-state magnet valve according to  claim 13 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to apply a pilot pressure to said application solenoid and allow said application solenoid to be closed and prevent said source pressure from exhausting to atmosphere.  
     
     
         15 . A method for wheel slip control using a three-state magnet valve according to  claim 8 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid valve and not energize said application pilot solenoid valve and allow a pilot pressure to hold said application solenoid valve open initially.  
     
     
         16 . A method for wheel slip control using a three-state magnet valve according to  claim 15 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to bias said release solenoid valve and hold said release solenoid valve closed.  
     
     
         17 . A method for wheel slip control using a three-state magnet valve according to  claim 16 , wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid and allow a pilot pressure to force said application solenoid valve closed and said release solenoid valve open allowing a fluid pressure to exhaust to atmosphere from said braking device while holding said source pressure steady.