MIL-DTL-25531F
3.6 Locking of parts. All threaded parts shall be locked by safety wiring, by self-locking nuts
conforming to MIL-DTL-32258, cotter pin, or other approved methods. Safety wire shall be
installed in accordance with NASM33540 and shall conform to NASM20995. The use of lock
washers, set screws or staking is not permitted unless specifically approved by the using service.
However, staking shall not be used where failure of the staking will allow any loose part in the
flow stream.
3.6.1 Coupling to fitting connection. Provision shall be made for positive locking of the hose
fitting to the coupling. The lock shall be of a reusable type.
3.7 Performance. The coupling shall function equally well with air flowing in either direction
and shall satisfy the applicable requirements when tested in accordance with 4.6.
3.8 Attachment. The force required to engage the coupling to the nipple shall not exceed 25
pounds. Attachment shall be made by inserting the coupling onto the nipple by virtue of the
handling ring (National Stock Number (NSN) 5340-01-323-5523) attached to the coupling
collar. The coupling shall be so constructed that in the unattached position it is ready for instant
connection to the aircraft nipple. It shall not be necessary to first retract the sleeve for
connection. The coupling shall also be so constructed that it will not become partially locked on
the nipple, allowing it to come off during the operation. Pulling on the hose normally connected
to the coupling shall not result in disengagement of the coupling.
3.9 Release. The coupling shall contain two methods of release from the aircraft nipple, a
primary and secondary release.
3.9.1 Primary. Primary release of the coupling shall be in pulling back on the handling ring and
not requiring a force of more than 30 pounds to release the coupling from the aircraft nipple.
This release shall leave the coupling in position for the next attachment.
3.9.2 Secondary. In the event the handling ring is not in use, disconnect can be made by simply
grasping the coupling sleeve and pulling it in the reverse direction. If for some reason a lanyard
is required such shall be constructed of a chain complying with or equivalent to RR-C-271, Type
1, Grade C, Class 5, Style 2, zinc coated, .15625 (Number 2) size with a T-type handle attached
to the free end. End connecting links shall be of equivalent welded and zinc coated steel wire.
The handle and 2 inch chain adjacent to the handle shall be covered with a heat resistant plastic
or rubber covering.
3.9.3 Safety device. An automatic pressure lock and a self-closing automatic mechanical safety
valve shall be provided for safety of operation. The pressure lock shall immobilize the primary
and secondary release when the coupling is in the engaged position and under pressure. The
pressure lock shall be so located that it is always accessible without disassembly of the coupling
for manual deactivation while the coupling is connected to the nipple. The automatic pressure
lock shall prevent disconnect of the coupling when the pressure is above 10 psi. It shall only be
necessary for the valve to sufficiently stop the air flow to prevent danger to operating personnel.
The device incorporated shall not be adversely affected by gravitational forces.
7
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business