GB1080670A - Fluid flow control valves - Google Patents

Abstract

1,080,670. Fluid-pressure brakes; valves. WAGNER ELECTRIC CORPORATION. Dec. 30, 1965 [Jan. 4, 1965 (2)], No. 55271/65. Headings F2F and F2V. Brake system.-A treadle-actuated application valve 9, Fig. 1, has a pair of inlet ports each connected by a separate auxiliary reservoir and a check valve to a main reservoir 3 charged by a compressor 2; the valve 9 is also provided with an emergency port that is either vented or open to the main reservoir 3 depending upon the position of a manual valve 24. A tractor valve (not shown) has three lines 5, 22 and 25 leading thereto, the lines 5, 25 being connected to the main reservoir 3 and the latter including a manual valve 25a similar to valve 24; line 22 is connected to a two-way valve 21 supplied from the two outlet ports of the valve 9 which ports are also connected to the brake motors 13, 19 on separate tractor axles. Application valve.-With the manual valves 24, 25a in the charging position fluid from the main reservoir 3 enters a control port 36, Fig. 2, and flows to a chamber 87 there lifting an emergency piston 84 against its spring 91. Fluid also flows through reservoirs 10, 16 and via inlet ports 34, 32, into piston inlet-chamber 57 and inlet chamber 27, respectively, and the parts occupy the positions shown. A manually-applied force on the metering spring 83 moves the reaction and emergency pistons 71, 84 against a return spring 73, the latter causing movement of a piston 52 against a further return spring 70 so that tubular elements 89, 69 simultaneously seat on valve members 67, 60 and isolate outlet chambers 72, 56 from atmosphere; the element 89 is integral with the emergency piston 84. Continued motion of this piston assembly unseats the members 67, 50 to establish communication between inlet and outlet ports 32, 33 and 34, 35. When the reaction force of the fluid pressure in chamber 72 equals the manually applied force, all the pistons move upwardly to " lap " the members 67, 50; " feel " is also imparted to the operator. Should the pressure in the main reservoir fall, the emergency spring 91 extends due to reduced pressure in chamber 87 to cause both valve members 67, 50 to open. The valves may also be operated by actuating valve 24 to vent the emergency chamber 87. The element 89 (Fig. 3, not shown) may be slidably arranged inside a further element 102 integral with the reaction piston 71 and only co-operates with the valve member 67 in emergency conditions. The piston 52 (Fig. 4, not shown) carries the tubular element 202 which coacts with valve member 50 and the tubular member depending from valve member 67 has a lostmotion connection with the piston 52. The emergency piston 84 (Fig. 5, not shown) is formed with a stepped extension 304 open to the pressure in outlet chamber to ensure a " lapped " position of the elements and valve members during emergency operation. In another form, the downward movement of the reaction piston 451, Fig. 6, and a relay piston-rod 498 causes a seat 469 on the emergency piston 464 to engage the valve member 448 and the rod 498 to pass through the relay piston 489 and bring a seat 500 near to the valve member 486. Further motion of the reaction piston 451 opens both valve members 448 and 486. The pressure in outlet chamber 452 passes via a passage 496 to act on and cause the relay piston 489 to abut and move the rod 498 so that seat 500 engages and then unseats the member 486. The reaction and emergency pistons 451, 468 may each embody seat portions which are telescopically arranged to separately coact with the valve member 448 during normal and emergency conditions, respectively.