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Title: Shutoff and exhaust valve for air brakes
Claims: I claim: 1. A valve comprising; a valve body having a hollow piston movable between first and second positions, said piston including an intermediate stepped portion, biasing means for normally biasing said piston to said first position, first and second ports communicating with one another past said stepped portion of said piston, third and fourth ports communicating with one another past one end portion of said piston, said piston having an opposite end portion communicating with atmosphere, movable valve means between said one end portion of said piston and said valve body for selectively blocking or establishing communication between said third and fourth ports and between said fourth port and the hollow interior of said piston past said one end portion thereof, said piston being movable from said first position to said second position under influence of pressure acting on said stepped portion thereof through said first port, in said first position of said piston said valve means being positioned for blocking communication between said third and fourth ports and between said fourth port and the hollow interior of said piston, in said second position of said piston said valve means being positioned for establishing communication between said third and fourth ports while blocking communication between said fourth port and the hollow interior of said piston upon application of pressure on said valve means through said third port and for establishing communication between said fourth port and the hollow interior of said piston while blocking communication between said third and fourth ports upon application of a higher to lower pressure differential across said valve means from said fourth port to said third port. 2. The valve of claim 1 wherein said valve body has a diaphragm valve member between said opposite end portion of said piston and atmosphere. 3. The valve of claim 1 wherein said valve body has a valve seat facing toward said one end portion of said piston and a bore extending from said valve seat to said fourth port, said third port being communicable with said bore past said valve seat, said valve means comprising a valve member of flexible material and including a valve member body portion having one side engageable with said seat and an opposite side engageable with said one end portion of said piston. 4. The valve of claim 3 wherein said valve member body portion includes a circumferential first lip extending longitudinally and radially outwardly therefrom adjacent said opposite side thereof and engaging said bore. 5. The valve of claim 4 including a circumferential second lip extending outwardly from said valve member body portion adjacent said one side thereof and engaging said valve body outwardly of said seat, and said second lip being stressed in said first position of said piston. 6. The valve of claim 3 including a circumferential lip extending outwardly from said body portion and engaging said valve body outwardly of said seat, and said lip being stressed in said first position of said piston. 7. The valve of claim 1 including a tractor-trailer air brake system including tractor service and emergency lines and trailer service and emergency lines, said first and second ports being respectively connected to said tractor emergency and trailer emergency lines, and said third and fourth ports being respectively connected to said tractor service and trailer service ports. 8. A valve including one port communicable past a seat and bore with another port, an elongated hollow member having one open end communicable with atmosphere and another open end positioned generally between said seat and said other port, a valve member of flexible material positioned between said seat and said other open end, said valve member being operative to establish communication between said ports while blocking communication between said ports and said other open end upon application of a higher to lower pressure differential across said valve member from said one port to said other port, and said valve member being operative to block communication between said ports while establishing communication between said other port and said other open end upon application of a higher to lower pressure differential across said valve member from said other port to said one port. 9. The valve of claim 8 including a circumferential lip extending outwardly from said valve member and engaging a surface of said valve outwardly of said seat, said lip normally being stressed in a direction tending to bias said valve member toward said other open end. 10. The valve of claim 9 including a second circumferential lip on said valve member engaging said bore between said ports and between said one port and said other open end. 11. The valve of claim 8 including a circumferential lip on said valve member engaging said bore between said ports and between said one port and said other open end. 12. The valve of claim 8 wherein said hollow member comprises a piston movable between a first position holding said valve member against said seat and a second position for releasing said valve member from engagement with said seat. 13. The valve of claim 12 including a circumferential lip extending outwardly from said valve member and engaging a surface of said valve outwardly of said seat, said lip being stressed in said first position of said piston in a direction tending to move said valve member away from said seat when said piston moves toward said second position. 14. The valve of claim 12 including a circumferential lip extending outwardly from said valve member and engaging said bore between said ports and between said one port and other open end. 15. In a tractor-trailer air brake system having tractor emergency and service lines and trailer emergency and service lines, a shutoff and exhaust valve respectively connecting said tractor and trailer emergency lines and said tractor and trailer service lines, said valve having a movable member which is movable between a first position blocking communication between said tractor and trailer service lines and a second position providing communication between said tractor and trailer service lines, biasing means for normally biasing said movable member to said first position, said movable member being movable to said second position under influence of a predetermined pressure acting thereon through said tractor emergency line, said valve having an exhaust port of establishing communication of said trailer service line with atmosphere, diaphragm valve means positioned between said tractor and trailer service lines and said exhaust port, said valve means being operative in said second position of said movable member to establish communication between said tractor and trailer service lines while blocking communication of said service lines with said exhaust port upon application of a higher to lower pressure differential across said valve means from said tractor service line to said trailer service line, and said valve means being operative in said second position of said movable member to block communication between said tractor and trailer service lines while establishing communication between said trailer service line and said exhaust port upon application of a higher to lower pressure differential across said valve means from said trailer service line to said tractor service line. 16. The system of claim 15 wherein said movable member comprises a piston having said exhaust port therein. 17. The system of claim 16 wherein said valve means includes a circumferential lip extending outwardly therefrom and engaging a surface of said shutoff and exhaust valve, said lip being resiliently stressed in said first position of said movable member in a direction tending to bias said valve means toward said movable member as said movable member moves toward said second position. 18. The system of claim 17 including a second outwardly extending circumferential lip on said valve means engaging a surface of said shutoff and exhaust valve between said tractor and trailer service lines and between said tractor service line and said exhaust port. 19. The system of claim 16 including an outwardly extending circumferential lip on said valve means engaging a surface of said shutoff and exhaust valve between said tractor and trailer service lines and between said tractor service line and said exhaust port. Other info: Inventors: Wheless, William B. (Owosso, MI, US) Application Number: 595581 Filing Date: 1975-07-14 Publication_date: 1976-08-03 Assignee: Midland-Ross Corporation (Cleveland, OH) Primary Class(es): 137/102 303/40 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Klinksiek, Henry T. Assistant Examiner: Attorney: Switzer; H. Duane |
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