Patent GB-1177368-A (GB)
Title: Improvements in or relating to drivers' brake valve arrangements
IPC: B60T15/18
Filed: 1967-04-07
Abstract: 1,177,368. Drivers' brake valves. KNORRBREMSE G.m.b.H. 7 April, 1967 [7 April, 1966], No. 16170/67. Heading F2F. In a driver's brake valve comprising a relay valve 7 controlled by two pressure regulators 3, 3<SP>1</SP> arranged at the driver's positions of a rail vehicle and including a valve arrangement 31, 38, 39, 41 actuated by a control piston 23 to control main brake pipe pressure a means operable automatically on initiation of a brake release operation to cause delivery of filling charges comprises a nozzle 15 and a second piston 16 in a passage between the compressed air source 1 and the piston chamber 27. The second piston controls an air discharge valve 18 controlling the pressure in a back control chamber 19 acting on the control piston 23 and a double valve 8, 9 also in the passage is controlled by a further piston 10 loaded on one side by the pressure controlled by the regulators 3 and on the other side by the pressure in the piston chamber 27. The pressure regulators 3, 3<SP>1</SP> are arranged on the two drivers' cabs of a rail vehicle in which a main reservoir pipe 1 is permanently charged with compressed air, the relay valve 7 being connected to a main air pipe 21. In modifications, the arrangement may include a filling charge valve, an equalizer, a quick-acting brake valve and/or shut-off devices for separating the relay valve 7 from the main air pipe 21 or for shutting down the relay valve 7. Operation.-In the brake release condition the regulators 3, 3<SP>1</SP> control the regulating pressure level in control pipe 5 and cylinder space 6. The piston 10 controls the double valve 8, 9 so that compressed air is admitted from space 11 or compressed air is discharged via release nozzle 13 to control the regulated pressure level in space 12 and control chamber 27. For braking the pressure in space 6 is reduced, so that piston 10 opens valve 9 to permit discharge to atmosphere, at a controlled rate, of the compressed air in space 12 and control chamber 27. This causes the control piston 23 to move to the right carrying with it a piston 29, and a valve pipe 30 attached thereto, until the pipe 30 disengages from sealing plate 31, thereby allowing compressed air in a space 22 and the main air pipe to discharge to atmosphere via pipe 30. The prevailing pressure in a backcontrol chamber 19 is reduced via a nozzle 20 to a level corresponding to the adjusted braking step, whereupon the parts move to the position shown to interrupt the discharge of air from the space 22 and main air pipe 21. To release the brakes the pressure in space 6 is increased so that piston 10 opens valve 8 to allow the flow of compressed air from cylinder space 14 into space 12 and control chamber 27. The reduced pressure in space 14 lifts piston 16 to open air-discharge valve 18 to vent the backcontrol chamber 19. The resulting pressure differential on piston 23 causes it to be moved to the left, the piston 29 and pipe 30 being also carried along by stop 28, sealing plate 31 is unseated and the engagement of stop pipe 24 with stop part 40 causes the unseating of sealing ring 39. This allows a high-speed filling charge of compressed air to flow from the main reservoir pipe through a large flow cross-section into space 22 and main air pipe 21. At the same time nozzle 34 clears the projection 33 and compressed air flows from control chamber 27 into space 35 and reservoir 37. The piston 29 therefore moves relative to piston 23 to open valve 31, 38. At a predetermined pressure level in space 6, valve 8 is closed interrupting the pressure rises in space 12 and control chamber 27, the pressures in spaces 14, 17 are equalized and piston 16 descends to close the air discharge valve 18. A pressure build up in the backcontrol chamber 19 via nozzle 20 occurs until this corresponds to the pressure in control chamber 27 so that piston 23 moves to the right to close nozzle 34 and valve 39, 41 is closed, thereby completing the high-speed filling charge. The pressure in space 35 gradually discharging through nozzle 36 holds the piston 29 in the left-hand end position relative to the piston 23 so that valve 31, 38 remains open temporarily to continue a low-speed filling charge until atmosphere pressure is reached in chamber 35.