Brake systems |
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| 申请号 | US39185073 | 申请日 | 1973-08-27 | 公开(公告)号 | US3844624A | 公开(公告)日 | 1974-10-29 |
| 申请人 | ABEX CORP; | 发明人 | JONES R; | ||||
| 摘要 | A brake system in which brake control units are isolated for redundancy and including a comparator to detect unacceptable degradation in available fluid pressure. | ||||||
| 权利要求 | 1. In a braking system where brake pressure is applied by fluidoperated pistons in related brake cylinders: an accumulator for storing fluid under pressure; a reservoir for storing fluid not under pressure; a pump means communicating with said accumulator and said reservoir for delivering fluid from said reservoir to charge said accumulator with fluid; a continuously variable directional valve interposed between said brake cylinders, said accumulator, and said reservoir, said directional valve being settable in a first position allowing fluid from said accumulator to communicate with said brake cylinders, and being settable in a second position allowing fluid from said brake cylinders to communicate with said reservoir, and a null position blocking flow between the accumulator and brake cylinders and betWeen the brake cylinders and the reservoir; a control system line communicating with said accumulator, said reservoir and with said directional valve, capable of providing a first pilot pressure urging said directional valve to said first position, and capable of allowing flow of fluid from said accumulator to said reservoir; a main control valve interposed in said control system line to variably restrict or enlarge flow through said control system line from said accumulator to said reservoir to vary said first pilot pressure; an orifice interposed between said directional valve and said brake cylinders; a release means capable of providing a second force in opposition to the force of said first pilot pressure, and urging said directional valve to said second position; a control means which controls said main control valve so that when brake pressure is to be applied, said main control valve restricts flow through said control system line thereby increasing the force from said first pilot pressure above the force from said release means causing said directional valve to be set in said first position, and so that when brake pressure is to be released, said main control valve enlarges flow through said control system line thereby decreasing the force from said first pilot pressure below the force from said release means causing said directional valve to be set in said second position. 2. In a brake system where brake pressure is applied by fluid-operated pistons in related brake cylinders: an accumulator for storing fluid under pressure; a reservoir for storing fluid not under pressure; a pump means communicating with said accumulator and said reservoir for delivering fluid from said reservoir to charge said accumulator with fluid; a continuously variable directional valve interposed between said brake cylinders, said accumulator, and said reservoir, said directional valve being settable in a first position allowing fluid from said accumulator to communicate with said brake cylinders, and being settable in a second position allowing fluid from said brake cylinders to communicate with said reservoir, and a null position blocking flow between the accumulator and brake cylinders and between the brake cylinders and the reservoir; a control system line communicating with said accumulator, said reservoir and with said directional valve, capable of providing a first pilot pressure urging said directional valve to said first position, and capable of allowing flow of fluid from said accumulator to said reservoir; a main control valve interposed in said control system line to variably restrict or enlarge flow through said control system line from said accumulator to said reservoir to vary said first pilot pressure; a release means capable of providing a second force in opposition to the force of said first pilot pressure, and urging said directional valve to said second position; a control means which controls said main control valve so that when brake pressure is to be applied, said main control valve restricts flow through said control system line thereby increasing the force from said first pilot pressure above the force from said release means causing said directional valve to be set in said first position, and so that when brake pressure is to be released, said main control valve enlarges flow through said control system line thereby decreasing the force from said first pilot pressure below the force from said release means causing said directional valve to be set in said second position; and, a parking brake means interposed in said control system line between said main control valve and said reservoir which is capable of completely blocking flow from said accumulator to said reservoir thereby increasing the force from said first pilot pressure above the force of said release means causing said directional valve to be set in said first position applying braking pressure until the pressure in said braking cylinders iS substantially equal to the pressure of said accumulator. 3. A system as in claim 2 wherein said parking brake means includes a motorized valve which is normally closed, blocking fluid flow, and is maintained open during operation of said system by normal operating conditions. 4. A system as in claim 3 wherein said normal operating conditions include a sufficient electrical supply as measured by either current or voltage. 5. In a brake system where brake pressure is applied by fluid-operated pistons in related brake cylinders: an accumulator for storing fluid under pressure; a reservoir for storing fluid not under pressure; a pump means communicating with said accumulator and said reservoir for delivering fluid from said reservoir to charge said accumulator with fluid; a continuously variable directional valve interposed between said brake cylinders, said accumulator, and said reservoir, said directional valve being settable in a first position allowing fluid from said accumulator to communicate with said brake cylinders, and being settable in a second position allowing fluid from said brake cylinders to communicate with said reservoir, and a null position blocking flow between the accumulator and brake cylinders and between the brake cylinders and the reservoir; a control system line communicating with said accumulator, said reservoir and with said directional valve, capable of providing a first pilot pressure urging said directional valve to said first position, and capable of allowing flow of fluid from said accumulator to said reservoir; a main control valve interposed in said control system line to variably restrict or enlarge flow through said control system line from said accumulator to said reservoir to vary said first pilot pressure; a release means capable of providing a second force in opposition to the force of said first pilot pressure, and urging said directional valve to said second position; a control means which controls said main control valve so that when brake pressure is to be applied, said main control valve restricts flow through said control system line thereby increasing the force from said first pilot pressure above the force from said release means causing said directional valve to be set in said first position, and so that when brake pressure is to be released, said main control valve enlarges flow through said control system line thereby decreasing the force from said first pilot pressure below the force from said release means causing said directional valve to be set in said second position; and, an emergency block valve interposed in said control system line between said main control valve and said directional valve which is normally closed, blocking fluid flow, and is maintained open during operation of said system by normal operating conditions; a moderating valve interposed in said control system line between said main control valve and said directional valve in parallel with said emergency block valve, which is normally closed, and is maintained open during operation of said system by abnormal operating conditions. 6. A system as in claim 5 including said braking pressure being applied to slow a pair of rotating axles which are affixed to wheels which roll upon a track, and said abnormal operating conditions which open said moderating valve include the skidding of any of the wheels upon the track. 7. A system as in claim 6 wherein said skidding is sensed by a difference in rotational speed between the axles. 8. A system as in claim 6 wherein said skidding is sensed by a difference in deceleration between the axles. 9. A system as in claim 6 wherein said moderating valve is a two position valve and said moderating valve is opened when abnormal skidding is detected, whereby said main control valve controls application of brake pressure. 10. A system as in claim 9 wherein said main control valve opens proportional to the magnitude of the abnormal operating condition. 11. In a brake system where brake pressure is applied by fluid-operated pistons in related brake cylinders: an accumulator for storing fluid under pressure; a reservoir for storing fluid not under pressure; a pump means communicating with said accumulator and said reservoir for delivering fluid from said reservoir to charge said accumulator with fluid; a shuttle valve communicating with said pump, said accumulator, and said reservoir, said shuttle valve allowing flow from said pump to said accumulator whenever the pressure between said pump and said shuttle valve is greater than the pressure between said shuttle valve and said accumulator, and allowing flow from said accumulator to said reservoir whenever the pressure between said accumulator and said shuttle valve is greater than the pressure between said shuttle valve and said pump; a continuously variable directional valve interposed between said brake cylinders, said accumulator, and said reservoir, said directional valve being settable in a first position allowing fluid from said accumulator to communicate with said brake cylinders, and being settable in a second position allowing fluid from said brake cylinders to communicate with said reservoir, and a null position blocking flow between the accumulator and brake cylinders and between the brake cylinders and the reservoir; a control system line communicating with said accumulator, said reservoir and with said directional valve, capable of providing a first pilot pressure urging said directional valve to said first position, and capable of allowing flow of fluid from said accumulator to said reservoir; a main control valve interposed in said control system line to variably restrict or enlarge flow through said control system line from said accumulator to said reservoir to vary said first pilot pressure; a release means capable of providing a second force in opposition to the force of said first pilot pressure, and urging said directional valve to said second position; a control means which controls said main control valve so that when brake pressure is to be applied, said main control valve restricts flow through said control system line thereby increasing the force from said first pilot pressure above the force from said release means causing said directional valve to be set in said first position, and so that when brake pressure is to be released, said main control valve enlarges flow through said control system line thereby decreasing the force from said first pilot pressure below the force from said release means causing said directional valve to be set in said second position. 12. A system as in claim 11 wherein a spring loaded check valve allowing flow from said pump to said shuttle valve is interposed between them. 13. A system as in claim 12 wherein a check valve allowing flow from said shuttle valve to said accumulator is interposed between them. 14. In a brake system where brake pressure is applied by fluid-operated pistons in related brake cylinders: an accumulator for storing fluid under pressure; a reservoir for storing fluid not under pressure; a pump means communicating with said accumulator and said reservoir for delivering fluid from said reservoir to charge said accumulator with fluid; a shuttle valve communicating with said pump, said accumulator, and said reservoir, said shuttle valve allowing flow from said pump to said accumulator whenever the pressure between said pump and said shuttle valve is greater than the pressure between said shuttle valve and said accumulator, and allowing flow from said accumulator to said reservoir whenever the pressure between said accumulator and said shuttle valve is greater than the pressure between said shuttle valve and said pump; a continuously variable directional valve interposed between said brake cylinders, said accumulator, and said reservoir, said directional valve being settable in a first position allowing fluid from said accumUlator to communicate with said brake cylinders, and being settable in a second position allowing fluid from said brake cylinders to communicate with said reservoir, and a null position blocking flow between the accumulator and brake cylinders and between the brake cylinders and the reservoir; a control system line communicating with said accumulator, said reservoir and with said directional valve, capable of providing a first pilot pressure urging said directional valve to said first position, and capable of allowing flow of fluid from said accumulator to said reservoir; a main control valve interposed in said control system line to variably restrict or enlarge flow through said control system line from said accumulator to said reservoir to vary said first pilot pressure; an orifice interposed between said directional valve and said brake cylinders; a release means capable of providing a second force in opposition to the force of said first pilot pressure, and urging said directional valve to said second position; a control means which controls said main control valve so that when brake pressure is to be applied, said main control valve restricts flow through said control system line thereby increasing the force from said first pilot pressure above the force from said release means causing said directional valve to be set in said first position, and so that when brake pressure is to be released, said main control valve enlarges flow through said control system line thereby decreasing the force from said first pilot pressure below the force from said release means causing said directional valve to be set in said second position; and, a parking brake means interposed in said control system line between said main control valve and said reservoir which is capable of completely blocking flow from said accumulator to said reservoir thereby increasing the force from said first pilot pressure above the force of said release means causing said directional valve to be set in said first position applying braking pressure until the pressure in said braking cylinders is substantially equal to the pressure of said accumulator; an emergency block valve interposed in said control system line between said main control valve and said directional valve which is normally closed, blocking fluid flow, and is maintained open during operation of said system by normal operating conditions; a moderating valve interposed in said control system line between said main control valve and said directional valve in parallel with said emergency block valve, which is normally closed, and is maintained open during operation of said system by abnormal operating conditions. 15. Brake systems as in claim 14 applying brake pressure to the wheels of a front and rear truck, each brake system including: opposed first and second check valves interposed between said shuttle valve and said accumulator and directional valve whereby fluid from said shuttle valve may only pass to said accumulator and directional valve when said first check valve is held open, and fluid may only pass from said accumulator and directional valve to said shuttle valve when said second check valve is held open; and, a selective means to alternately hold open either first or second check valve whereby either front or rear or both trucks can be disabled from braking. 16. Brake systems as in claim 14 applying brake pressure to the wheels of a front and rear truck, including: a differential pressure analyzer means interposed between said front and rear braking systems so as to be able to sense the pressure of the fluid in both the front and rear brake cylinders and produce an emergency signal when the difference between the pressure of said front and rear brake cylinders exceeds a predetermined value. 17. A brake system as in claim 14 including: a suspension system containing a fluid under pressure where said pressure increases as the weight carried by said suspension system increases; And, an overload relief valve communicating with said accumulator, said reservoir, said control system line and pressure from said suspension system and capable of providing a path for fluid flow from said accumulator to said reservoir parallel to the path through said main control valve, and which is urged closed by a bias spring and pressure from said suspension system thereby blocking fluid flow between said accumulator and said reservoir, and which is urged open by pressure from said control system line thereby allowing fluid to flow from said accumulator to said reservoir. 18. A brake system as in claim 17 which requires a pressure in said control system line to be the maximum amount necessary to stop a suspension system carrying its minimum weight in order to overcome said bias spring force and open said overload relief valve. 19. A brake system as in claim 18 which requires pressure in said control system line to be the maximum amount necessary to stop a suspension system carrying a load in order to overcome the combined forces of said bias spring and said pressure from said suspension system wherein the maximum amount of pressure in said control system line is proportional to the pressure in said suspension system. 20. A brake system as in claim 19 wherein said overload relief valve regulates the control system line pressure when said emergency block valve is closed. 21. A brake system as in claim 20 wherein said moderating valve operates to proportionally release pressure when skidding is detected. 22. Brake systems as in claim 20 applying brake pressure to the wheels of a front and rear truck of a railroad car, so that the brake pressure applied to each truck is proportional to the load carried by each suspension system of the respective truck. 23. A brake system as in claim 22 wherein the load on each suspension system varies due to passenger or cargo distribution in the car. 24. Brake systems as in claim 17 applying brake pressure to the wheels of a front and rear truck, each brake system including: opposed first and second check valves interposed between said shuttle valve and said accumulator and directional valve whereby fluid from said shuttle valve may only pass to said accumulator and directional valve when said first check valve is held open, and fluid may only pass from said accumulator and directional valve to said shuttle valve when said second check valve is held open; and, a selective means to alternately hold open either first or second check valve whereby either front or rear or both trucks can be disabled from braking. 25. Brake systems as in claim 17 applying brake pressure to the wheels of a front and rear truck, including: a differential pressure analyzer means interposed between said front and rear braking systems so as to be able to sense the pressure of the fluid in both the front and rear brake cylinders and produce an emergency signal when the difference between the pressure of said front and rear brake cylinders exceeds a predetermined value. 26. Brake systems as in claim 15 applying brake pressure to the wheels of a front and rear truck, including: a differential pressure analyzer means interposed between said front and rear braking systems so as to be able to sense the pressure of the fluid in both the front and rear brake cylinders and produce an emergency signal when the difference between the pressure of said front and rear brake cylinders exceeds a predetermined value. 27. Brake systems as in claim 24 applying brake pressure to the wheels of a front and rear truck, including: a differential pressure analyzer means interposed between said front and rear braking systems so as to be able to sense the pressure of the fluid in both the front and rear brake cylinders and produce an emergency signal when the difference between the pressure of said front and rear brake cylinders exceeds a predetermined value. 28. A brake system as in claim 14 including a brake mode valve interposEd between and communicating with said accumulator, and said directional valve and said control system line including an electrical control means which is capable of closing said brake mode valve, thereby blocking fluid flow from said accumulator to said directional valve or said control system line. 29. A brake system as in claim 28 including a pneumatic means to override said brake mode valve and open said brake mode valve thereby allowing fluid flow from said accumulator to said directional valve or said control system line when abnormal operating conditions are sensed. 30. A brake system as in claim 29 used in a train wherein said pneumatic means includes an air equalization pipe connecting all the cars of the train and where said abnormal operating conditions include less than full air pressure is said air equalization pipe. |
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