Improvements in or relating to fluid controlled safety devices for selector valves

摘要

1,070,924. Valves; change speed control. NATIONAL RESEARCH DEVELOPMENT CORPORATION. March 3, 1964 [March 4, 1963], No. 8503/63. Headings F2D and F2V. A safety control means for the supply of fluid under pressure from a common source of supply to separate supply lines, e.g. to actuate the cylinders associated with the brake bands of epicyclic gearing, comprises a group of two or more selector valves 4b, 7b or 9b each of which controls a separate supply line 13, 14 or 15, respectively, wherein on actuation of any selector valve to connect its supply line to the source of supply 11, fluid under pressure is also applied to the other valve or valves of the group to prevent actuation thereof whilst the selected valve remains in position to allow the flow of fluid to its associated supply line. The valves 4b, 7b and 9b are housed in bores 5, 8 and 10, respectively, and each has a piston 4a, 7a or 9a located above and joined to it by a hollow stem 17 and a freely movable piston 4c, 7c or 9c located below it. Each valve is moved axially in a bore by a solenoid energized actuator 1, 2 or 3, against the action of a spring 18. Normally each valve is disposed in its upper position and when, e.g., valve 4b is moved by the actuator 1, exhaust line 12 is closed and pressure inlet 11 is connected with supply line 13. Auxiliary line 19 also supplies fluid to chambers below piston 7c and valve 9b to counteract any action by energization of their actuators 2 and 3. Similar auxiliary lines 20 and 21 connect with supply line 14 and lines 22 and 23 connect with supply line 15. In a further embodiment a selected valve, e.g. controlling a reverse gear, is moved back to the normal position if another actuator is inadvertently energized.