When disconnected, the union nut remains with the
S1 half. The S4 half has a mounting flange for
attaching to a bulkhead or other structural member of
the aircraft.
All parts referred to in the following paragraphs
are identified in figure 2-39. The two halves of the
coupling may be connected by placing the tubular
valve (1) within the protruding nose (6) of the mating
half, and rotating the union nut in a clockwise
direction. The union nut must be rotated until its teeth
(5) fully engage the lock spring (8). A properly
tightened coupling will have compressed the lock
spring until a 1/16-inch minimum gap exists between
the inside lip of the spring retainer fingers and the
spring plate. Figure 2-40 shows the coupling both
properly connected and improperly connected.
The locking action may be followed by referring
to figure 2-39. Positive locking is assured by the
locking spring (8) with teeth, which engage ratchet
teeth on the union nut (5) when the coupling is fully
connected. The lock spring automatically disengages
when the union nut is unscrewed. An O-ring packing
(3) seals against leakage as the coupling halves are
joined. Positive opening of the valves occurs as the
halves are connected.
When the coupling halves are joined, the
protruding nose (6) of the S4 half contacts the sleeve
(4) of the S1 half. Simultaneously, the head of the
tubular valve (1) contacts the face of the poppet valve
(7), thus preventing air from entering the system.
Tightening the union nut pulls the coupling halves
together. This causes the nose of the S4 half to push
the sleeve into the S1 half, uncovering the ports to the
tubular valve. At the same time, the head of the
tubular valve depresses the poppet valve.
When the coupling halves are fully connected, the
sleeve and poppet valve have reached the positions
shown in the left-hand view of figure 2-40. The nose
of the S4 half has engaged the O-ring packing of the
S1 half, providing a positive seal.
Figure 2-40.—Quick disconnects properly and improperly connected.
2-29
