GB1393524A - Coupling devices - Google Patents

Abstract

1393524 Pipe couplings; valves AVERY-HARDOLL Ltd 13 April 1972 [13 April 1971] 9296/71 Headings F2G and F2V In a quick-release coupling, e.g. for refuelling an aircraft on the ground, valve operation may be effected pneumatically or by means of a spring. The coupling may be secured to a fuel reservoir hydrant (not shown), by a bayonet connection, made by introducing rollers 18 into the axial parts of L-shaped slots in the hydrant. On rotating the housing 10, to lock the rollers 18 in the circumferential parts of the slots, tongues 24 are retained in the axial parts and prevent ring 19 from being rotated. Rod 73, which is mounted on housing 10, is thus carried away from stop 23, which is fixed to ring 19. The rod 73 is spring urged so that, on being removed from stop 23, it retracts axially away from snail cam 72, thus unlocking shaft 71 and the link arm assembly 70, 34 for the main valve member 32. On completing the bayonet connection, pip 43 opens a corresponding valve member in the hydrant and liquid, under reservoir pressure, flows through holes 44, duct 41 and out of holes 42 into space 38, where it exerts pressure on balancing piston 33, which is essentially insufficient to open the valve member 35. Space 38 is vented, through duct 48 and restrictor valve 45, to the interior 11 of the housing. To disenable the pneumatic control and prevent the valve member 32 from being opened inadvertently, when the coupling is released, port 55 in spool valve 56 is vented to atmosphere. However, as rod 73 retracts axially, it carries the spool 60 with it to connect port 55 to port 62 and thus provide a path, for compressed air, from port 53 to cylinder space 69. A remotely located changeover air valve is operated, through a dead man's control, to supply air to port 53 and to vent port 52 to atmosphere. Piston rod 34 is thus driven axially to open valve member 32 at a speed controlled by needle valve 64. When valve member 32 is open, cam 72 is positioned to prevent rod 73 from being moved, by handle 75A, clear of stop 23, so that the bayonet connection cannot then be released. On reversing the connections at ports 52 and 53, piston 35 returns the valve member 32 to the closed position, in which rod 73 can be moved, by handle 75A, to disenable the pneumatic control and allow the housing 10 to be rotated, relatively to the hydrant, to disengage the bayonet connection.