Breathing mask supply tube release

A release comprises cylindrical first and second connectors having supply passages, one of which is mounted on the supply tube and the other of which is mounted on the mask. The first connector has a cylindrical chamber for receiving a cylindrical portion of the second connector to connect the connectors and operatively connect the tube to the mask to enable supply of breathing gas to the mask. The second connector has a groove formed in its outer surface for receiving a split spring ring carried by the first connector. The free ends of the arms of the split ring have cam surfaces. A spring is mounted on the second connector and is compressed by insertion of the second connector. An unlocking device comprises an electrically-actuated explosive device carried within the first connector and a wedge which is projected against the cam surfaces upon actuation to force the spring arms apart, to force the split ring out of the groove. This unlocks the couplings which are forced apart by the spring, connecting the mask wearer to ambient atmosphere through the mask supply passage.

FIELD OF THE INVENTION 
This invention relates generally to breathing masks and, more particularly, 
to a device for releasing a supply tube from a breathing mask to open the 
mask to ambient atmosphere. 
BACKGROUND OF THE INVENTION 
Pilots and other aircrew members are normally provided with a breathing 
mask, commonly called an oxygen mask, which is mounted on a protective 
helmet. The breathing mask is supplied with a pressurized supply of 
breathing gas, carried by the aircraft, through a supply tube. This 
arrangement enables the aircrew to function at altitudes where the ambient 
atmosphere is too "thin" to provide an adequate supply of oxygen to permit 
human functioning. 
The supply tube usually has a coupling for attachment to an aircraft supply 
port. This coupling is automatically disconnected upon ejection of the 
aircrew during an aircraft emergency. Thus the aircrew member is ejected 
with a length of supply hose dangling from the mask. 
If the ejection results in descent into a body of water, it is conventional 
for the aircrewman to remove the mask to prevent submersion of the 
dangling tube end into the water, thus enabling breathing of the ambient 
air or atmosphere. If the person is unconscious, injured or otherwise 
unable to manually release the mask, drowning will ensue due to oxygen 
deprivation or water inhalation. 
It is thus necessary to automatically remove the mask to prevent drowning 
of an unconscious person wearing the mask. 
U.S. Pat. Nos. 4,803,980 and 4,869,245 to Nowakowski et al both disclose 
explosive devices for disconnecting a mask from a helmet in response to an 
electrical signal generated by immersion of a detector in water. 
Arrangements of this type prevent drowning of the mask wearer due to 
immersion of the supply tube in water and are adequate for that purpose. 
However, there are certain circumstances where a mask release is inadequate 
to provide breathing access for the mask wearer and prevent drowning. In 
one application, the mask is attached to a chemical defense hood that is 
worn by the aircrewman beneath the helmet and is attached to the helmet. 
In this instance, any release of the mask from the helmet does not remove 
the mask from the wearer, since it remains attached to the hood that is 
trapped beneath the helmet. 
It is therefore desirable to provide a device which automatically provides 
breathing access to ambient atmosphere for the wearer of a helmet-mounted 
breathing mask while leaving the mask attached to the helmet. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a device for automatically 
providing access to ambient atmosphere for the wearer of a helmet-mounted 
breathing mask while leaving the mask attached to the helmet. 
In accordance with this invention, a release is provided for releasing a 
supply tube from a breathing mask which comprises a first connector 
mounted on the supply tube and having a supply passage, a second connector 
mounted on the mask and having a supply passage, the connectors 
interfitting to operatively connect the tube tothe mask by connecting the 
supply passages and a locking device having a locked position maintaining 
the first and second connectors connected and an unlocked position 
disconnecting the first and second connectors. The release includes an 
unlocking means to move the locking device to its unlocked position and 
biasing means for positively separating the first and second connectors 
when unlocked to open the mask supply passage to ambient atmosphere. 
In a preferred embodiment, the release comprises first and second 
connectors having supply passages, one of which is mounted on the supply 
tube and the other of which is mounted on the mask. The first connector 
has a cylindrical chamber for receiving a cylindrical portion of the 
second connector to connect the connectors and operatively connect the 
tube to the mask to enable supply of breathing gas to the mask. The second 
connector has a groove formed in its outer surface for receiving a split 
ring carried by the first connector. The split ring is formed of spring 
material and has a normal unstressed position occupying the groove. A 
spring is mounted in the first connector and is compressed by insertion of 
the second connector. An unlocking device comprises an 
electrically-actuated explosive device carried within the first connector 
and a conical plunger which is projected upon actuation against the cam 
surfaces to force the free ends of the split ring apart, expanding the 
split ring out of the groove. This unlocks the couplings which are forced 
apart by the spring, connecting the mask wearer to ambient atmosphere 
through the mask supply passage. 
Thus a release according to this invention provides for the positive 
release of the supply tube from the breathing mask while leaving the mask 
attached to the helmet. It also provides a release which is independent of 
the manual mask-to-helmet connector. 
These and further features of this invention are further explained in the 
following detailed description of the invention as illustrated in the 
attached drawings, in which:

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIG. 1 of the drawings, an aircrew eye respiratory 
protection (AERP) system 10 is provided for protecting an aircrewman from 
injury due to exposure to chemical and biological warfare agents. The AERP 
includes a protective hard helmet 12 having a protective face visor 14 and 
an underlying hood 16. 
A breathing, or oxygen mask, 18 is mounted to the hood for supplying 
breathing gas to the mask wearer through a supply tube 20 which is 
conventionally connected at its other end (not shown) to a supply port 
mounted in an aircraft. This mask 18 is sealed to the hood 16 to enable 
the supply of breathing gas which is required at high altitudes where the 
atmosphere is too "thin" to provide sufficient oxygen to enable the wearer 
to function. The secure supply of breathing gas is also required during a 
chemical or biological warfare attack to enable exclusion of toxic ambient 
air from the wearers breathing process. 
The supply tube incorporates a release coupling 22, for a purpose to be 
described later, and has a communication wire assembly 24 loosely wound 
around it. The communication wire assembly 24 extends from inside the mask 
18 to a connector (not shown) in the aircraft to conventionally provide 
the wearer with a communication link. 
In the event of an aircraft malfunction requiring the aircrew to exit the 
aircraft, the connections of the breathing gas supply tube 20 and the wire 
assembly 24 to the aircraft are automatically disconnected by conventional 
means as the aircrewman is ejected from the aircraft. Subsequent breathing 
of the aircrewman is from ambient atmosphere through now-open end (not 
shown) of breathing gas supply tube 20. 
The aircrewman is easily supplied with ambient air, which will contain 
sufficient oxygen, upon descent to earth. This arrangement is adequate to 
assure oxygen supply to the aircrewman, whether conscious or unconscious, 
so long as the descent is to dry land. However, the situation changes 
dramatically should the descent be into a watery environment, such as an 
ocean or a lake. 
In this case, the dangling free end of the supply tube 20 will become 
immersed in water due to gravity. If the aircrewman is conscious, he can 
merely remove the helmet and hood from his head and breathe the ambient 
air. This maneuver is not possible if the aircrewman is unconscious. The 
unfortunate result in this case is that the free end of tube 20 will 
become immersed in the water and the aircrewman will suffocate or drown 
via inhalation of water, unless other provisions are made to assure a 
supply of breathable gas. 
To assure breathing access to the ambient atmosphere, supply tube 20 
incorporates releasable coupling 22, which will now be described with 
reference to FIGS. 2-4. Coupling 22 includes a cylindrical inner member or 
connector 26 having a supply passage 28 that includes large radial holes 
30, only one of which is shown. The outer end of member 26 includes a 
shoulder 32 for conventional clamping attachment (not shown) to the mask 
18 or to the mask-end portion 20a of tube 20. 
Intermediate its ends, the outer surface 34 of member 26 includes a pair of 
spaced shoulders defining an annular groove 36 that receives an O-ring 38. 
Further inward, outer surface 34 incorporates a conical camming surface 40 
that terminates in another annular groove 42. 
The outer member or connector 43 of coupling 22 has a cylindrical outer end 
44 which terminates in an annular shoulder 46 for attachment to the remote 
end 20b of tube 20 by conventional clamping means (not shown). A 
cylindrical supply passage 48 opens into an enlarged chamber 50 at annular 
shoulder 52, which slidingly receives the inner end, or nozzle, 54 of 
member 26. 
Outwardly of chamber 50, member 43 has an outer casing 56 that houses a 
potted circuit board 58. Mounted at the outer end of casing 56 is a member 
60, which has circumferentially-spaced open chambers that house a 
plurality of electrical contacts 62. The casing 56 houses an explosive 
squib 64 for operating a decoupling actuator 66. 
A split spring locking ring 68 is confined in an enlarged annular groove 
70. As best shown in FIG. 5, locking ring 68 Contains a plurality of 
circumferentially-spaced notches 72 which define inwardly depending 
locking fingers 74. Ring 68 is split radially to provide a slot 75 in ring 
68. As illustrated in FIG. 3, the outside diameter of ring 68 is smaller 
than the inside diameter of groove 70, while fingers 74 extend 
sufficiently into groove 42 to lock inner member 26 to outer member 43. In 
the locked condition of FIG. 2, a coil spring 76 is compressed between 
inner member end 54 and the shoulder 52 of chamber 50. O-ring 38 is 
compressed to provide a seal between groove 36 and the surface defining an 
aperture 77 in an annular flange 78 carried by outer member 43. 
Casing 56 contains a cylindrical satellite chamber 80 which houses squib 64 
and decoupling actuator 66. Actuator 66 has a central nose 82 sized to fit 
within slot 75 in its unstressed state, as shown in FIG. 5. From nose 82, 
a conical camming surface 84 extends rearwardly and outwardly to an outer 
shoulder 85 and an annular groove 86 which houses an O-ring that seals 
against the annular wall of chamber 80. Axially outwardly of groove 70, 
outer member 43 includes a compound stop surface 88 that is profiled to 
match the nose 82 and camming surface 84 of actuator 66. 
As shown in FIG. 3, casing 56 includes a radially-extending annular battery 
chamber 90 which houses a stack of conventional wafer batteries 92 and is 
closed by a cap 94. Batteries 92, contacts 62, circuit board 58 and squib 
64 are conventionally electrically interconnected so that completion of a 
circuit by connecting contacts 62 will provide an electrical charge to 
fire squib 64. 
Operation will now be described. Coupling 22 is assembled by inserting 
nozzle 54 through the aperture 77 to engage and begin compressing spring 
76. Camming surface 40 will engage fingers 74 and expand spring split ring 
68 outwardly into groove 70 until O-ring 38 enters and sealingly engages 
the periphery of aperture 77. Then spring fingers 74 will register with 
and enter groove 42 to lock members 26 and 43 together, with spring 76 
compressed. The sections 22a and 22b are now operatively connected to 
enable the supply of breathing gas through coupled passages 28 and 48, 
which are sealed by O-ring 38, to mask 18. A substantial compressive force 
is stored in spring 68. 
Should the aircrewman be forced to eject from his aircraft and descend into 
water, coupling 22 will automatically separate as follows. When contacts 
62 are immersed in water, an electrical circuit will be completed and 
squib 64 will fire in a well-known manner. 
The explosive force provided by the firing of squib will drive actuator 66 
further into slot 75. Conical camming surface 84 will expand split ring 68 
outwardly into groove 70. This expansion continues until the motion of 
actuator 66 is stopped by engagement with stop surface 88. The inner 
diameter of the fingers 74 of the expanded ring 68 is now larger than the 
outside diameter of inner member 26. 
This expanded condition of the split ring 68 is maintained by the 
cylindrical surface of actuator shoulder 85 which is wedged into slot 75, 
as shown in phantom lines in FIG. 5. This enables spring 76 to forcefully 
expel inner member 26 from outer member 43, thus separating coupling 22 
and enabling the supply of ambient air to mask 18 through the end of 
nozzle 54 and radial holes 30. 
FIG. 6 illustrates an alternate to the split spring ring previously 
described. In this embodiment a split ring 100 would have the same outer 
ind inner dimensions so as to directly replace split ring 68. Split ring 
100 comprises a pair of arms 102 and 104 that are pivoted together by a 
pin 106. Opposite pivot pin 106, the arms 102 and 104 terminate in 
respective chamfered surfaces 108 and 110 to form an axially converging, 
radially extending "V". The arms are aperture adjacent these chamfered 
surfaces to receive shear pins 112 and 114 that would be carried in mating 
apertures in casing 56 adjacent slot 70 to close the split in ring 100. 
Nozzle 54 would be inserted in chamber 50 and then pins 112 and 114 would 
be inserted to maintain engagement of locking tabs 116 and 118 in groove 
42. An actuating member shaped like member 66 could be used, but, 
preferably, a ball 120 would utilized. 
Firing of squib 64 would drive ball 120 against chamfered surfaces -08, 110 
and drive arms 102 and 104 apart, shearing pins 112 and 114 in the 
process. Thereafter, spring 76 would expel inner member 26, separating 
coupling 22 as described above. 
Thus, this invention provides a coupling for a breathing mask supply hose 
that automatically separates upon water contact to enable the supply of 
ambient air to the mask.